Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Scanner Utilizing Light Pipe with Diffuser
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a scanner and more particularly to
scanners
that include light shaping variable diffusers incorporated in light pipe
systems.
2. Description of Related Art
Presently, conventional scanning systems, such as bar code recognition
systems,
use point source illumination, such as light emitting diodes (LEDs) and point
reading.
These systems often include bar code illuminators that scan along a series of
bar codes.
Such bar code illuminators can be used in hand held housings that can be swept
back
and forth across a bar code until the bar code is processed by a detector
system in the
bar code recognition system. Alternatively, the bar code illuminator can be
placed in a
stationary system and the bar code itself can be moved back and forth across
the bar
code illuminator until the detector system processes the bar code.
Unfortunately, such bar code illuminators require bulky housing and fixturing.
In the case of laser scanner illuminators, such systems require moving
mechanical parts,
such as vibrating or rotating mirrors and collecting optics. Another
disadvantage of
laser scanners is an eye safety problem that can be hazardous to a users of
the laser
scanner.
A diffuser can be useful in scanning systems. Unfortunately, present diffusers
only diffuse light at one diffusion angle. In particular, present diffusers do
not
gradually vary the diffusion angle across an axis of the diffuser.
Furthermore, present
diffusers do not gradually vary the diffusion angle depending on a location on
the
diffuser.
There is also presently a failure to recognize the usefulness of diffusers in
various applications. For example, there is a failure to recognize the
usefulness of a
diffuser in a scanner application. Additionally, there is a failure to
recognize the
usefulness of diffusers in other applications, such as encoders and sensors.
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Current encoders can be used to encode data that represents the position or
movement of an object. These encoders can be used, for example, on steering
wheels
in automobiles to count the number of revolutions a steering wheel is turned.
These
encoders can also be used, for example, on DC motors and other motors that
have
linear states for robotic applications where objects are moved with extreme
precision.
In such an application, the encoder can be used to calculate the number of
turns that a
motor makes to determine the distance that a shield has moved.
Unfortunately, such encoders are relatively bulky and take up excessive space
in
a system in which they are employed. For example, such encoders cannot be
employed
in a relatively planar manner.
A similar problem exists for scanners, such as scanners used in barcode
readers.
Because of the need for light projection and focusing, current scanners take
up
excessive space in systems and housings in which they are employed. For
example,
such scanners, like the encoders, cannot be employed in a relatively planar
manner.
SUMMARY OF THE INVENTION
The present invention provides a scanner. The scanner can include a light
source emitting light to a light pipe and a detector array. The light source
can emit
light through the light pipe to the detector array. The light pipe can include
a reflective
surface and a diffuser. The reflective surface can reflect light, directly or
indirectly
towards the diffuser and the diffuser can diffuse light out of the light pipe.
The light
pipe can further include a reflective groove that reflects light from the
reflective surface
towards the diffuser. The diffuser can diffuse the light to an object that
reflects the
light to the detector array. The object may be a bar code, paper money, or any
other
object that can be scanned. The diffuser may be a variable diffuser.
The variable diffuser can include a holographic medium and a diffusion pattern
that gradually varies in diffusion angle across the holographic medium so that
the
variance in diffusion angle is imperceptible to the naked eye. The diffusion
pattern can
include many diffusion patterns with different angles, the diffusion patterns
overlapping
each other to create a gradually varying diffusion angle. The diffusion
patterns may
overlap each other by 10 percent of the area of each diffusion pattern and the
diffusion
patterns may vary across an axis of the holographic medium.
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A variable diffuser master may be used to create the variable diffuser. The
variable diffuser master can be created by a system using a light source that
projects
light, a mask located in the path of the light projected from the light source
and an
opening in the mask, the opening being variable in size and the opening
passing light
through the mask. The system can include a plate where the opening in the mask
passes
light through the mask to the plate and the light source can project light
through the
opening in the mask onto sequential overlapping portions of the plate. The
system can
also include a blocker that blocks some of the light projected from the light
source. The
system can further include a first shield with an opening in the path of the
light and a
second shield with an opening located in between the mask and the plate. The
distances
between and the sizes of the components of the system can be varied as
sequential light
projections are made onto the plate in order to achieve gradually varying
diffusion
patterns on the plate. This plate with gradually varying diffusion patterns
can be used
to create a variable holographic diffuser with such a pattern so that
variances between
varying diffusion patterns are imperceptible.
The variable diffuser may also be used in a device for sensing light or a
sensor.
The sensor can include a waveguide, a light source, a device for collimating
light and a
light detector. The device for collimating light may be a collimating lens and
the
waveguide can preserve the collimation of the light. The device for
collimating light
may also be a variable diffuser located within the waveguide where the
variable diffuser
collimates the light before the light exits the waveguide. The light source
and the
detector may both be located on the same side of the waveguide on a printed
circuit
board. An encoder can be located in between the waveguide and the detector.
The
waveguide can include metalized ends and a side containing facets.
By using the variable diffuser and/or waveguides and light pipes in sensors
and
scanners, the sensors and scanners can be reduced to sizes that were not
obtainable
without the use of variable diffusers and light pipes. Additionally, improved
accuracy
of scanning and sensing can be obtained through the use of variable diffusers
and light
pipes due reduced size and more precise diffusion patterns. Furthermore, more
visually
accurate displays can be obtained through the use of variable diffusers
because
variations between different diffusion angles are imperceptible.
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BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiments of the present invention will be described with
reference to the following figures, wherein like numerals designate like
elements, and
wherein:
Fig. 1 is an exemplary illustration of a method of manufacturing a variable
diffuser;
Fig. 2 is an exemplary illustration of a plate;
Fig. 3 is an exemplary illustration of a mask;
Figs. 4-7 are exemplary illustrations of varying widths of a slit on a mask;
Fig. 8 is an exemplary illustration of overlapping diffusion patterns;
Fig. 9 is an exemplary illustration of a direction of movement of a plate;
Fig. 10 is an exemplary illustration of various diffusing patterns;
Fig. 11 is an exemplary illustration of a direction of movement of a plate;
Fig. 12 is an exemplary illustration of various diffusing patterns;
Figs. 13-16 are exemplary illustrations of varying widths and heights of a
slit;
Fig. 17 is an exemplary illustration of diffusion patterns;
Fig. 18 is an exemplary illustration of a direction of movement of a plate;
Fig. 19 is an exemplary illustration of diffusing patterns;
Fig. 20 is an exemplary illustration of a direction of movement of a plate;
Fig. 21 is an exemplary illustration of diffusing patterns;
Fig. 22 is an exemplary diagram of a system for manufacturing a variable
diffuser;
Figs. 23-26 are exemplary illustrations of varying dimensions of a slot and a
blocker;
Fig. 27 is an exemplary illustration of resulting diffusion patterns on a
plate;
Fig. 28 is an exemplary illustration of a symmetric variable diffuser;
Fig. 29 is an exemplary illustration of an asymmetric variable diffuser;
Fig. 30 is an exemplary illustration of a variable diffuser in a backlight
display;
Fig. 31 is an exemplary illustration of a sensor;
Fig. 32 is an exemplary illustration of a sensor according to another
embodiment;
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Fig. 33 is an exemplary illustration of a sensor according to another
embodiment;
Fig. 34 is an exemplary illustration of a bar code scanner;
Fig. 35 is an exemplary illustration of a scanner according to another
5 embodiment;
Fig. 36 is an exemplary illustration of a scanner according to another
embodiment;
Fig. 37 is an exemplary illustration of a scanner according to another
embodiment;
Fig. 38 is an exemplary illustration of a light pipe system;
Fig. 39 is an exemplary illustration of a light pipe system according to
another
embodiment;
Fig. 40 is an exemplary illustration of a light pipe system; and
Fig. 41 is an exemplary illustration of a light pipe system according to
another
embodiment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Fig. 1 is an exemplary diagram of a system 100 for manufacturing a variable
diffuser or a variable diffuser master plate according to a first embodiment.
The
variable diffuser master may be used to create subsequent variable diffusers
on
holographic mediums by imprinting a pattern on the variable diffuser master
onto the
holographic mediums. The system 100 can include a collimated light source such
as a
laser 110, an objective lens 120, a cylindrical lens 130, a mask 140 and a
plate 150.
All of the components of system 100 can be located along an axis x. The plate
150 may
= be located a distance d along axis x from the mask 140. In operation, the
laser 110 may
project light through the objective lens 120, the cylindrical lens 130 and the
mask 140 to
the plate 150 to create a diffusion or speckle characteristic on plate 150.
The objective
lens 120, the lens 130 and the mask 140 can be varied in size, shape, and
distance from
each other depending on a shape of speckle desired on the plate 150.
The cylindrical lens 130 can be varied to get a specific footprint, or
diffuser
angle on the plate 150. The plate 150 can be a glass plate coated with a
photosensitive
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or photoresistant material which may be water resistant. The distance d may be
varied
to obtain a specific speckle pattern.
Fig. 2 is an exemplary illustration of the plate 150 of Fig. 1. The plate 150
as
well as the entire system 100 may be located on an x, y and z coordinate
system. For
example, the plate 150 may be located a distance d away from the mask 140
along the x
axis.
Fig. 3 is an exemplary illustration of the mask 140 of Fig. 1. The mask 140
can
include a first side mask 310 and a second side mask 320 located a distance w
from
each other. The first side mask 310 and the second side mask 320 can be used
in
combination to create a opening or slit 330 of width w in the mask 140. The
first side
mask 310 and the second side mask 320 may vary in distance from each other
along the
y axis of Fig. 2. In operation, the distance w between the side masks 310 and
320 can
be varied to affect the distribution of light projected from the laser 110
onto the plate
150. This variance can create a variable angle of diffusion along the plate
150. For
example, a larger distance w between the side masks can create a larger angle
of
diffusion on the pate 150. A smaller distance w between the side masks can
create a
smaller angle of diffusion on the plate 150.
In other words, the slit width w can be varied to control the amount of light
that
passes through the slit 330. A smaller width w will result in less light
passing through
the slit 330, which directly corresponds to the profile obtained on the plate
150. A
narrower width w can create a narrower elliptical angle and a wider width w
can create
a wider elliptical profile.
By exposing and then moving the plate 150 and varying the width w, a variety
of
different angles can be recorded on the same plate. These adjustments can be
made in a
stepwise manner to obtain a proper distribution angle on the plate 150.
Accordingly,
diffusion angles can be varied in a stepwise manner so that the diffusion
patterns on the
plate 150 overlap. Thus, a variable diffuser can be created that has a gradual
diffusion
pattern, which means no perceptible break in diffusion angles.
Additionally, the plate 150 may be repositioned along any of the axes of Fig.
2
and the width w of the slit 230 may be adjusted so that when light is
projected from the
laser 110 onto the plate 150, the angle of diffusion can vary at different
positions on the
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plate 150. Furthermore, the plate 150 may be repositioned in increments so
that light
projected from the laser 110 overlaps in incremental positions along the plate
150 as the
width w of the slit 230 is varied. This overlap along the plate 150 may result
in a
variance of the angle of diffusion. The resulting diffuser created on the
plate 150 can
then diffuse light at different angles at different positions so that the
variance in
diffusion angles is imperceptible to the naked eye. For example, the light
projected
onto the plate 150 can overlap by 10 percent of the area of the light
projected onto the
plate 150. Accordingly, the resulting plate is a variable diffuser that
diffuses light at
varying angles in a gradual manner.
Figs. 4-7 are exemplary illustrations of varying widths w of slit 230 on the
mask
140. For example, the width w of slit 230 may be varied to achieve slits of
width 0.2
mm, 0.5 mm, 1 mm and 3 mm as shown in Figs. 4-6 respectively. Fig. 8 is an
exemplary illustration of resulting overlapping diffusion patterns 810-860 on
plate 150
from the varying widths of slit 230. In operation, the plate 150 can move
along the y
axis while the width w of slit 230 is varied to achieve diffusion patterns 810-
840.
Fig. 9 is an exemplary illustration of a direction of movement of plate 150
along
the y axis as the slit 230 changes in width. According to a preferred
embodiment, the
plate 150 moves along the y axis horizontally incrementally, or in steps. At
each
incremental change, the light is projected onto the plate 150 to create
overlapping or
varying diffusion patterns on the plate 150. According to another embodiment,
the
movement of the plate 150 and the variance of the width of the slit 230 may be
automated so that the slit 230 varies in width while the plate 150 is moved to
create a
variable diffusing pattern on the plate 150. Fig. 10 is an exemplary
illustration of
various diffusing patterns that may be created on plate 150. Diffusing
patterns 1-4, 5-8,
9-12 and 13-16 correspond to slit widths 0.2 mm, 0.5 mm, 1 mm and 3 mm
respectively.
Fig. 11 is an exemplary illustration of a direction of movement of plate 150
along the z axis as the slit 230 changes in width. According to a preferred
embodiment,
the plate 150 moves along the z axis vertically incrementally, in steps, or
automatically
as disclosed according to Fig. 9. Fig. 12 is an exemplary illustration of
various
diffusing patterns that may be created on plate 150 according to vertical
movement.
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Figs. 13-16 are exemplary illustrations of varying widths w and heights h of
slit
230 on mask 140. In this embodiment, additional side masks may be used to vary
the
height of slit 230. For example, the width w and height h of slit 230 may be
varied to
achieve slits of dimensions 0.2 x 4 mm, 0.2 x 8 mm, 0.2 x 16 mm and 0.2 x 32
mm as
shown in Figs. 13-16 respectively. Fig. 17 is an exemplary illustration of
resulting
diffusion patterns 810-860 on plate 150 from the varying widths of slit 230
according to
Figs. 13-16 respectively. As the length of the slit is changed, the major
angle of the
diffuser is changed.
Fig. 18 is an exemplary illustration of a direction of movement of plate 150
along the y axis as the slit 230 changes in dimension. According to a
preferred
embodiment, the plate 150 moves along the y axis horizontally incrementally,
in steps
or continuously. The plate 150 may move along the y axis continuously by use
of an
automated system. At each incremental change, the light is projected onto the
plate 150
to create varying or overlapping diffusion patterns on the plate 150. Fig. 19
is an
exemplary illustration of various diffusing patterns that may be created on
plate 150.
Fig. 20 is an exemplary illustration of a direction of movement of plate 150
along the z axis as the slit 230 changes in dimension. According to a
preferred
embodiment, the plate 150 moves along the z axis vertically incrementally, in
steps, or
continuously as disclosed according to Fig. 9 for proper projection of light
onto the
plate 150. Fig. 21 is an exemplary illustration of various diffusing patterns
that may be
created on plate 150 according to vertical movement.
Fig. 22 is an exemplary diagram of a system 2200 for manufacturing a variable
diffuser according to another embodiment. The system 2200 can include a laser
2210,
an objective lens 2220, a first shield 2230, a mask 2240, a blocker 2250, a
second
shield 2260 and a plate 2270. All of the components of system 100 can be
located
along an axis x. The first shield can include a slot 2235 and the second
shield can
include a slot 2265. Fig. 22 illustrates the second shield 2260 and the plate
being
located at various positions Pl-P4 along the x axis. The system 2200 can be
located on
a similar coordinate system to that illustrated in Fig. 2. In operation, the
laser 2210
may project light through the objective lens 2220, the first shield 2230, the
mask 2240,
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the blocker 2250 and the second shield 2260 to the plate 2270 to create a
diffusion
characteristic on plate 2270.
Figs. 23-26 are exemplary illustrations of varying dimensions of the slot 2253
and the blocker 2250 which can vary according to the locations P4-PI
respectively. For
example, Fig. 26 illustrates that there may be a very large or no shield 2230
and a very
small or no blocker 2250 used for position P1. The variance of resulting
speckles on
the plate 2270 may be created sequentially and/or overlapping and
incrementally or
continuously as disclosed according to the previous figures. Fig. 27 is an
exemplary
illustration of resulting varying diffusion or speckle patterns on plate 2270
from the
varying dimensions and locations Pl-P4 of the elements of system 2200. Larger
circles
represent larger angles.
The above-disclosed systems can be used to various types of variable diffusers
that gradually change diffusion angle throughout the diffuser. A gradual
change in
diffusion angle means that the incremental change in diffusion angle is
imperceptible to
the naked eye. This gradual change is created by overlapping diffusion
patterns. The
gradual change may also be created by an automated continual creation of the
diffusion
patterns by continually moving a plate while changing at least a slit in a
mask. Various
types of variable diffusers that can be created can include symmetric and
asymmetric
variable diffusers.
Fig. 28 is an exemplary illustration of a symmetric variable diffuser 2800.
The
symmetric variable diffuser can have symmetrical variance in a diffusion angle
along
the diffuser. For example, the diffuser may vary gradually from 3 degrees at
the edge
of the diffuser to 20 degrees at the center of the diffuser and back to 3
degrees at the
opposite edge of the diffuser.
Fig. 29 is an exemplary illustration of an asymmetric variable diffuser 2900.
The asymmetric variable diffuser can have a gradual asymmetrical variance in a
diffusion angle along the diffuser. For example, the diffusion angle can vary
gradually
from a lower angle at one end to a higher angle at another end. In another
example, the
diffusion angle can vary at different locations along the variable diffuser
depending on
the intended application of the variable diffuser.
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Fig. 30 is an exemplary illustration of a variable diffuser in a backlight
display
3000. The backlight display 3000 can include a variable diffuser 3010 and
light sources
3020 and 3030 located at opposing ends of the variable diffuser 3010. In
operation, the
light sources 3020 and 3030 may provide light to the backlight display 3000.
The
5 variable diffuser 3010 can reflect light at varying angles along a vertical
axis along the
backlight display 3010. For example, the vertical angle may vary from 20
degrees at
the center of the variable diffuser 3010 to 3 degrees at the edges of the
variable diffuser
3010. Additionally, the backlight display may comprise only one light source
3020 at
one edge of the variable diffuser 3010. In such an embodiment, the variable
diffuser
10 3010 may vary a diffusion angle in an asymmetric manner along the vertical
axis of the
variable diffuser 3010.
Fig. 31 is an exemplary illustration of an encoder or sensor 3100. The sensor
3100 may include a light source 3110 such as an LED, light 3115 projected from
the
light source 3110, a collimating lens 3120, an encoder disk 3140, holes 3150
in the
encoder disk 3140 and a detector 3130 such as a photodetector. In operation,
the light
source 3110 projects light 3115 to the collimating lens 3120. The collimating
lens 3120
collimates the light 3115 for projection to the encoder disk 3140. The encoder
disk
3140 can rotate about an axis of the encoder disk 3140. The detector 3130
detects the
light 3115 that passes through the holes 3150 of the encoder disk 3140. When
the
encoder disk 3140 rotates, the detector 3130 can detect variances in the light
3115.
Additionally, the holes 3150 may be aligned in a specific pattern. By aligning
the holes
3150 in a specific pattern, the detector 3130 can detect variances in the
light 3115 to
determine the position of the encoder disk 3140. The detector 3130 can send
signals to
an external system to allow the system to determine when, to what extent and
with what
velocity the encoder disk 3140 rotates about its axis. The external system can
also
determine the position of the encoder disk 3140 from the signals sent from the
detector
3130. The systems disclosed are not limited to encoder disks. The systems
disclosed
may be used with a moving sheet or any other device that may be useful in a
sensor.
Fig. 32 is an exemplary illustration of a sensor 3200. The sensor.3200 may
.include a light source 3210 such as an LED, light 3215 projected from the
light source
3210, a collimating lens 3220, a waveguide 3230 such as a holographic
lightpipe, an
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encoder disk 3240, holes 3250 in the encoder disk 3240, a detector 3260 such
as a
photodetector and a printed circuit board (PCB) 3270. The waveguide 3230 may
be
supported on the PCB 3270 by pins 3280. The waveguide 3230 can have ends 3233
and 3236. The ends 3233 and 3236 may be metallized in order to reflect light
3215.
Additionally, the ends 3233 and 3236 may be positioned at an angle between 30
and 50
degrees from the bottom of the waveguide 3230. The light source 3210 and the
detector 3260 may lie substantially in the same plane and may both be attached
to the
PCB 3270.
In operation, the light source 3210 projects light 3215 to the collimating
lens
3220. The collimating lens 3220 collimates the light 3215 for projection
through the
waveguide 3230 to the encoder disk 3240 and then to the detector 3260. The
waveguide retains the collimation of the light 3215 and passes the light to
the encoder
disk 3240. The encoder disk 3240 can rotate about an axis of the encoder disk
3240.
The detector 3260 detects the light 3215 that passes through the holes 3250 of
the
encoder disk 3240. When the encoder disk 3240 rotates, the detector 3260 can
detect
variances in the light 3215 in the same manner as disclosed for sensor 3100.
Fig. 33 is an exemplary illustration of a sensor 3300 according to another
embodiment where similar elements correspond to element numbers of Fig. 32. As
illustrated, the sensor 3300 does not need to use a collimating lens 3220. The
sensor
3300 may use a variable diffuser in the form of a variable reflector, a
metalized groove
or facets 3310 located within the waveguide 3230. The facets or variable
diffuser may
be located at the bottom 3380 of the waveguide 3230. 'The facets 3310 can
collimate
the light 3215 as it passes through the waveguide 3230. For example, the
variable
diffuser can be located on the bottom of the waveguide 3230 and can employ
varying
angles of reflection to result in a collimated light leaving the deflector to
the encoder
disk 3240. Additionally, the waveguide 3230 does not need to adjust the light
3215 180
degrees as illustrated. The waveguide 3230 may guide the light 3215 out the
side of the
waveguide 3230 so the encoder disk 3240 and the detector 3260 can be located
at the
side of the waveguide 3230. Furthermore, the waveguide 3230 may guide the
light
3215 so that the light can be guided out of the top of the waveguide 3230 to
an encoder
disk 3240 and a detector 3260 located above the waveguide 3230.
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The disclosed encoders may be used in, for example, automotive applications to
detect, for example, the number of revolutions a steering wheel is turned. The
disclosed encoders may also be used in, for example, robotics applications to
determine
the amount of movement of a robotic arm. Accordingly, the disclosed encoders
have a
wide variety of applications for any situation where it is desirable to
determine the
position or movement of an object.
Fig. 34 is an exemplary illustration of a scanner 3400. The scanner 3400 may
include a housing 3410, light sources 3420, light 3425 emitted from the light
sources
3420, lenses 3430, a focusing lens 3440 and a detector array 3450. The light
sources
3420 may be surface mount light emitting diodes (LEDs). All of the components
of
scanner 3400 may be attached to the housing 3410 as illustrated in Fig. 34.
In operation, the light sources 3420 emit light 3425 that is projected through
the
lenses 3430. The lenses 3430 may have a diffraction grating which directs the
light
3425 to a barcode 3460 where the light 3425 is reflected back to a focusing
lens 3440.
The focusing lens 3440 can focus and expand the light 3425 onto a detector
array 3450.
The detector array 3450 can then detect the pattern of the barcode 3460.
Fig. 35 is an exemplary illustration of a scanner 3500 according to another
embodiment. The scanner 3500 can include light sources 3510, light 3515
emitted from
the light sources 3510, a light pipe or waveguide 3520, a focusing lens 3530,
and a
detector array 3540. The light sources 3510 may be surface mount LEDs.
Additionally, the light pipe 3520 can include sides that comprise a metalized
surface
3522, a total internal reflection (TIR) groove 3524, and a variable diffuser
3526.
In operation, the light sources 3510 can emit light 3515 that enters the light
pipe
3520. The light 3515 can be reflected off of the metalized surface 3522 to the
TIR
grooves 3524. The TIR grooves 3524 can reflect and redirect the light 3515 to
the
variable diffuser 3526. The variable diffuser 3526 can then focus the light
3515 onto an
object such as a barcode 3550. The variable diffuser 3526 can be implemented
so that
the portion of the variable diffuser 3526 farther away from the center of the
scanner
3500 redirects the light 3515 at an angle greater than the portion of the
variable diffuser
3526 closer to the center of the scanner 3500. Accordingly, the variable
diffuser 3526
may have a smaller angle of diffusion farther from the center of the scanner
3500 and a
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larger angle of diffusion closer to the center of the scanner 3500. Therefore,
the light
3515 can be more efficiently directed towards the barcode 3550. The barcode
3550 can
then reflect the light to the focusing lens 3530. The focusing lens 3530 can
focus the
light onto the detector array 3540 where the detector array 3540 can detect
the pattern
on the barcode 3550.
By reducing the size of the scanner 3400 down to the size of the scanner 3500,
a
more compact design can be realized. Additionally, the smaller scanner 3500
can be
more accurate because the light 3515 has less distance to travel before being
detected by
the detector array 3540.
Fig. 36 is an exemplary illustration of a scanner 3600 according to another
embodiment. The scanner 3600 can include light sources 3610, light 3615
emitted from
the light sources 3610, a light pipe 3620 and a detector array 3630. The light
sources
3610 may be surface mount LEDs. Additionally, the light pipe 3620 can include
sides
that comprise a metalized surface 3622, a total internal reflection (TIR)
groove 3624,
and a variable diffuser 3626.
In operation, the light sources 3610 can emit light 3615 that enters the light
pipe
3620. The light 3615 can be reflected off of the metalized surface 3622 to the
TIR
grooves 3624. The TIR grooves 3624 can reflect and redirect the light 3615 to
the
variable diffuser 3626. The variable diffuser 3626 can then focus the light
3615 onto a
detector array 3630. The variable diffuser 3626 can be implemented so that the
portion
of the variable diffuser 3626 farther away from the center of the scanner 3600
redirects
the light 3615 with a diffusion angle greater than the portion of the variable
diffuser
3626 closer to the center of the scanner 3600. Accordingly, the variable
diffuser 3626
may have a smaller angle of diffusion farther from the center of the scanner
3600 and a
larger angle of diffusion closer to the center of the scanner 3600.
Fig. 37 is an exemplary illustration of a scanner 3700 according to another
embodiment. The scanner 3700 can include light sources 3710, light 3715
emitted from
the light sources 3710 and a light pipe 3720. The light sources 3710 may be
surface
mount LEDs. Additionally, the light pipe 3720 can include sides that comprise
a
metalized surface 3722 and a reflective variable diffuser 3724.
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In operation, the light sources 3710 can emit light 3715 that enters the light
pipe
3720. The light 3715 can be reflected off of the metalized surface 3722 to the
reflective
variable diffuser 3724. The reflective variable diffuser 3724 can reflect and
redirect the
light 3715 out of the light pipe 3720. In a preferred embodiment, the variable
diffuser
can collimate the light 3715 before the light 3715 exits the light pipe 3720.
Accordingly, the variable diffuser 3724 can be implemented as a symmetric
variable
diffuser so that the portion of the variable diffuser 3724 farther away from
the center of
the scanner 3700 redirects the light 3715 with a diffusion angle greater than
the portion
of the variable diffuser 3724 closer to the center of the scanner 3700.
Therefore, the
variable diffuser 3724 may have a smaller angle of diffusion farther from the
center of
the scanner 3700 and a larger angle of diffusion closer to the center of the
scanner
3700.
Fig. 38 is an exemplary illustration of a light pipe system 3800. The light
pipe
system 3800 can include a light source 3810, light 3815 emitted from the light
source
3810 and a light pipe 3820. The light source 3810 may be a surface mount LED.
Additionally, the light pipe 3820 can include at least one side that comprises
a metalized
surface 3822 and a variable diffuser 3824 in the form of a reflective variable
diffuser.
In operation, the light source 3810 can emit light 3815 that enters the light
pipe
3820. The light 3815 can be reflected off of the metalized surface 3822 to the
variable
diffuser 3824. The variable diffuser 3824 can reflect and redirect the light
3815 out of
the light pipe 3820. In a preferred embodiment, the variable diffuser 3824 can
collimate the light 3815 before the light 3815 exits the light pipe 3820.
Accordingly,
the variable diffuser 3824 can be implemented so that the portion of the
variable
diffuser 3824 farther away from the light source 3810 redirects the light 3815
with a
diffusion angle greater than the portion of the variable diffuser 3824 closer
to the light
source 3810. Therefore, the variable diffuser 3824 may have a smaller angle of
diffusion closer to the light source 3810 and a larger angle of diffusion
farther from the
light source 3810.
Fig. 39 is an exemplary illustration of a light pipe system 3900 according to
another embodiment. The light pipe system 3900 can include a light source 3910
located at a side of the light pipe system, light 3915 emitted from the light
source 3910,
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a light pipe 3920 and a detector array 3940. The light source 3910 may be a
surface
mount LED. Additionally, the light pipe 3920 can include at least one side
that
comprises a reflective sheet such as a metalized surface 3922 and a variable
diffuser
3924.
5 In operation, the light source 3910 can emit light 3915 that enters the side
of the
light pipe 3920. The light 3915 can be reflected off of the diffuser surface
3924. The
variable diffuser 3924 can redirect the light 3915 out of the light pipe 3920
to the
detector array 3940. Accordingly, the variable diffuser 3924 can be
implemented so
that the portion of the variable diffuser 3924 farther away from the light
source 3910
10 redirects the light 3915 with a diffusion angle greater than the portion of
the variable
diffuser 3924 closer to the light source 3910. Therefore, the variable
diffuser 3924 may
have a smaller angle of diffusion closer to the light source 3910 and a larger
angle of
diffusion farther from the light source 3910.
Fig. 40 is an exemplary illustration of a light pipe system 4000 according to
15 another embodiment. The light pipe system 4000 can include a light source
4010, light
4015 emitted from the light source 4010 and a light pipe 4020. The light
source 4010
may be a surface mount LED and may be located at the side of the light pipe
4020.
Additionally, the light pipe 4020 can include a variable diffuser 4022 in the
form of a
reflective variable diffuser.
In operation, the light source 4010 can emit light 4015 that enters the light
pipe
4020. The variable diffuser 4022 can reflect and redirect the light 4015 out
of the light
pipe 4020. Accordingly, the variable diffuser 4024 can be implemented so that
the
portion of the variable diffuser 4022 farther away from the light source 4010
redirects
the light 4015 with a diffusion angle greater than the portion of the variable
diffuser
4022 closer to the light source 4010. Therefore, the variable diffuser 4024
may have a
smaller angle of diffusion closer to the light source 4010 and a larger angle
of diffusion
farther from the light source 4010.
Fig. 41 is an exemplary illustration of a light pipe system 4100 according to
another embodiment. The light pipe system 4100 can include a light source 4110
located at a side of the light pipe system, light 4115 emitted from the light
source 4110,
a light pipe 4120 and a light shaping diffuser 4140. The light source 4110 may
be a
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surface mount LED. Additionally, the light pipe 4120 can include at least one
side that
comprises a reflective sheet such as a metalized or total internal reflection
(TIR) surface
4122 and a variable diffuser 4124.
In operation, the light source 4110 can emit light 4115 that enters the side
of the
light pipe 4120. The light 4115 can be reflected off of the diffuser surface
4124. The
variable diffuser 4124 can redirect the light 4115 out of the light pipe 4120
through the
light shaping diffuser 4140. The light shaping diffuser 4140 can than shape
the light
exiting the light pipe 4120. Accordingly, the variable diffuser 4124 can be
implemented so that the portion of the variable diffuser 4124 farther away
from the light
source 4110 redirects the light 4115 with a diffusion angle greater than the
portion of
the variable diffuser 4124 closer to the light source 4110. Therefore, the
variable
diffuser 4124 may have a smaller angle of diffusion closer to the light source
4110 and
a larger angle of diffusion farther from the light source 4110.
The scanners disclosed are not limited to barcode scanning. For example, the
scanner 3500 can be used as a currency or bill acceptor. In operation,
currency may be
fed into, for example, a vending machine. The scanner 3500 can then scan the
currency to validate the currency and to determine the value of the currency.
In such an
embodiment, the barcode 3550 of Fig. 35 can be replaced with the currency for
proper
operation. The detector array 3540 can be used to detect characteristics of
the
currency.
The variable diffusers can be used in various applications, such as elevator
floor
number displays, roadside signs, airport departure signs, store signs, exit
signs,
architectural lighting, gas station signs, automotive displays, cockpit
displays, medical
sensors, sensor illumination, sources for sensors in machine vision, global
positioning
system units, bank terminals, toys or industrial applications.
This invention is not limited to the specific combinations of elements
illustrated.
The elements illustrated may be interchangeable to achieve the benefits of
each
embodiment among the other embodiments. For example, a form of the light pipes
disclosed in Figs. 37-40 may be combined with the sensor 3300 in Fig. 33 to
achieve
proper collimation before sending light through the encoder 3240 to the
detector 3260.
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17
As many changes therefore may be made to the embodiments of the invention
without
departing from the scope thereof. It is considered that all matter contained
herein be
considered illustrative of the invention and not in a limiting sense.
