U.S. patent application number 10/486097 was filed with the patent office on 2004-09-09 for capacitive proximity sensor for detecting component belts, component feeding device and method for detecting component belts.
Invention is credited to Pallas, Dirk.
Application Number | 20040175257 10/486097 |
Document ID | / |
Family ID | 7694921 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040175257 |
Kind Code |
A1 |
Pallas, Dirk |
September 9, 2004 |
Capacitive proximity sensor for detecting component belts,
component feeding device and method for detecting component
belts
Abstract
The invention relates to a capactive proximity sensor for
detecting component belts, comprising at least two electrically
conductive sensor surfaces (151, 152) which are arranged opposite
each other on a non-conducting substrate having a low dielectricity
number, whereby the component belts which are to be detected are
detected in the millimetre range as a result of the low dielectric
number of the substrate material and the geometric arrangement of
the sensor surfaces (151, 152).
Inventors: |
Pallas, Dirk; (Landsberg,
DE) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O.BOX 8910
RESTON
VA
20195
US
|
Family ID: |
7694921 |
Appl. No.: |
10/486097 |
Filed: |
February 9, 2004 |
PCT Filed: |
August 8, 2002 |
PCT NO: |
PCT/EP02/08905 |
Current U.S.
Class: |
414/222.02 ;
324/658 |
Current CPC
Class: |
H03K 17/955
20130101 |
Class at
Publication: |
414/222.02 ;
324/658 |
International
Class: |
B65H 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 9, 2001 |
DE |
10139158.7 |
Claims
1. Capacitive proximity sensor for detecting component tapes, said
sensor having an electrically non-conducting substrate made of low
dielectric constant material, and at least two electrically
conductive sensor surfaces (151, 152) implemented facing one
another on the substrate, so that because of the dielectric
constant of the substrate material and the arrangement of the
sensor surfaces (151, 152) on the substrate, component tapes (200)
to be detected can be detected in the millimeter range.
2. Capacitive proximity sensor according to claim 1, wherein the
dielectric constant of the substrate material is between 3 and 4
and the detection distance between 0.1 and 25 mm.
3. Capacitive proximity sensor according to claim 1 or 2, wherein
the sensor surfaces (151, 152) are disposed in a single plane.
4. Capacitive proximity sensor according to one of claims 1 to 3,
wherein the sensor surfaces (151, 152) are implemented in a meander
or interdigitated pattern and the meanders or fingers of the sensor
surfaces are intermeshed with a predetermined clearance with
respect to one another.
5. Capacitive proximity sensor according to claim 4, wherein the
predetermined clearance of the sensor surfaces with respect to one
another is constant for the entire sensor.
6. Capacitive proximity sensor according to one of claims 1 to 5,
wherein a first sensor surface is an essentially rectangular basic
surface having an extension disposed thereon in a first direction,
wherein the extension has a plurality of fingers in each case, and
wherein facing said extension there is disposed a second sensor
surface which is provided with fingers so as to leave a
meander-shaped interspace (300) between the first sensor surface
and second sensor surface.
7. Capacitive proximity sensor according to claim 6, wherein the
sensor (150) has a symmetrical structure with respect to the
rectangular basic surface relative to the first direction, so that
altogether the first sensor surface (151) has extensions
respectively in and counter to the first direction, of which the
extension disposed in the first direction faces the second sensor
surface (152) and the extension disposed counter to the first
direction faces the third sensor surface (153) which is implemented
and disposed symmetrically with respect to the second sensor
surface (152).
8. Capacitive proximity sensor according to one of claims 1 to 5,
wherein a first sensor surface is an essentially rectangular basic
surface having two extensions disposed thereon in a first
direction, the extensions each having a plurality of fingers which
are disposed facing the fingers of the other extension in each
case, and a second sensor surface being disposed between the
extensions which is provided with fingers facing the first sensor
surface and the second sensor surface in such a way that a
meander-shaped interspace (300) remains between the first sensor
surface and the second sensor surface.
9. Capacitive proximity sensor according to claim 8, wherein the
sensor (160) has a symmetrical structure with respect to the
rectangular basic surface relative to the first direction, so that
altogether there are formed the first sensor surface (161) with two
extensions respectively in and counter to the first direction, the
second sensor surface (162) between the two extensions disposed in
the first direction and a third sensor surface (163), similar to
the second sensor surface (162), disposed between the two
extensions disposed counter to the first direction.
10. Capacitive proximity sensor according to claim 7, 9 or 10,
wherein the first sensor surface is electrically connected to a
reference potential.
11. Capacitive proximity sensor according to claim 7 or 9, wherein
the sensor (150, 160) in the first direction is essentially made
twice as long as an object to be detected.
12. Component feeding device with a component transporting device
by means of which components can be transported in a feeding
direction to an unloading position, and a sensor by means of which
the presence or absence of objects can be detected, wherein the
sensor is a capacitive proximity sensor according to one of claims
1 to 11 which is disposed in proximity to the unloading
position.
13. Component feeding device according to claim 12, wherein the
objects are components and/or coupling elements suitable and used
for joining component tapes together.
14. Component feeding device according to claim 13, wherein the
coupling elements are conductive and can be connected to a
reference potential.
15. Component feeding device according to one of the preceding
claims, wherein the sensor is integral with a feeding channel
through which the components can be transported to the unloading
position.
16. Component feeding device according to one of the preceding
claims, additionally having an evaluation device by which a sensor
output signal can be processed.
17. Component feeding device according to claim 16, wherein the
evaluation device is set up in such a way that digital filtering of
the output signal is performed.
18. Method for detecting component tapes by means of a feeding
device according to one of claims 12 to 17, wherein an electric
field is applied between the sensor surfaces of the capacitive
proximity sensor, the field applied is detected using the
capacitive proximity sensor, the field detected is analyzed by an
evaluation device, and from the analyzed field it is determined
whether there is an object between the sensor surfaces.
19. Method according to claim 18, wherein a component disposed in a
component tape and/or a splicing strip for joining two component
tapes is detected as the object to be detected.
20. Method according to claim 18 or 19, wherein by means of a
capacitive proximity sensor according to claim 7, 9, 10 or 11 a
first field detected between the first sensor surface and the
second sensor surface and a second field detected between the
second sensor surface and the third sensor surface are compared
with one another in order to determine environmentally caused
disturbances in the field applied between the sensor surfaces, and
the disturbances determined are taken into account in the analyzing
of the detected field.
Description
[0001] Capacitive proximity sensor for detecting component tapes,
component feeding device and method for detecting component
tapes
[0002] The invention relates to a capacitive proximity sensor for
detecting component tapes, a component feeding device and a method
for detecting component tapes in which the component tapes to be
detected are detected by means of a field.
[0003] The invention further relates to a component detection
device for component feeding devices, a component feeding device
and a method for feeding components by means of a component feeding
device.
[0004] In the automatic component placement machine, e.g. for SMD
components, the components to be inserted are transported by means
of feeding devices to pick-up positions from which they can be
unloaded and inserted on a printed circuit board e.g. using a
revolver head. The components are often disposed in component
tapes. These are provided with a cover tape which is peeled back in
the feeding device at least at the component pick-up position in
order to enable the components to be unloaded. Although a large
number of components are disposed in each component tape, it may
also happen during operation that a component tape becomes empty
and a new component tape has to be made available to the feeding
device. In this case the end of the old component tape is joined to
the start of the new component tape, e.g. using a splicing element
which can be a metal strip.
[0005] In order to ensure an optimum placement process, it is
necessary to reliably detect the joints in the component tapes and
the end of the tape. For this purpose splice sensors are already
known from EP 967 851 or EP 859 543. These concepts each teach a
splice sensor which is mounted on the feeding device. However, the
distance between the splice sensor and the pick-up position is very
great, with the result that serious inaccuracies occur in
determining the components still present in the component tape or
in determining the position of the joint in the component
tapes.
[0006] Also known is a method whereby, for example, components to
be fed to an automatic placement machine are detected by means of a
light barrier while they are passing through a component feeding
device. For this purpose, for example in a component feeding
channel in the component feeding device, an opening is formed in
two opposite walls of said feeding channel so that an optical
measuring path of the light barrier can be routed through the
opening. Components transported along the feeding channel can be
detected by this means if they interrupt the measuring path of the
light barrier. However, detecting components by means of a light
barrier has several disadvantages. For example, when using a light
barrier as a detector for the components, an optical measuring path
must always be provided. This can be provided either by
implementing two mutually aligned openings in opposite walls of the
feeding channel or by implementing one opening and appropriately
mounting a reflex mirror on the feeding channel wall opposite said
opening.
[0007] However, problems may arise at the opening or openings
therefore required in the feeding channel while the components are
being transported through the feeding channel. For example,
components may become stuck at the edge region of the openings,
thereby making further transportation of the components along the
feeding channel impossible, whereas the measuring path of the light
barrier is simultaneously interrupted, indicating that components
are continuing to be transported.
[0008] Particularly in the context of increasing component
miniaturization, it is difficult to detect components by means of a
light barrier. The smallest components of the current generation
have a diameter of just a few tenths of a millimeter. Consequently,
the openings through which the components in the feeding channel
are to be detected using the light barrier must have an even
smaller diameter than the diameter of the components. However, such
openings are very difficult and costly to manufacture.
[0009] The object of the present invention is therefore to create a
sensor for detecting component tapes, a component feeding device
and a method for detecting component tapes in which detection can
be performed inexpensively and with a high degree of accuracy.
[0010] This object is achieved by a capacitive proximity sensor
having the features detailed in claim 1, a component feeding device
having the features detailed in claim 12 and a method for detecting
component tapes having the features detailed in claim 18. Preferred
embodiments of the invention are claimed in the dependent
claims.
[0011] The capacitive proximity sensor according to the invention
can be manufactured easily and inexpensively, as at least two
conductive sensor surfaces can be easily and inexpensively
implemented, e.g. by etching, on an electrically non-conducting
substrate, e.g. printed circuit board material. In addition, the
capacitive proximity sensor according to the invention can also be
implemented with very small dimensions, so that it can be disposed
in a feeding channel in the component feeding device in close
proximity to, or directly at, the component pick-up position. This
allows the joint between two component tapes to be detected in
close proximity to, or directly at, the pick-up position, thereby
enabling precise insertion of the end of the empty component tape
and the start of the spliced-on component tape. Because of the
small or non-existent distance of the sensor in the component
feeding device from the pick-up position, a high degree of
detection accuracy is ensured.
[0012] According to the invention, the relative permittivity of the
substrate material is selected such that optimum detection of
components and/or splicing elements is possible, it being critical
for success according to the invention that a low permittivity is
selected, i.e. much lower than for normal printed circuit board
material which has a relative permittivity .epsilon..sub.r of
between 10 and 20.
[0013] Preferably the material from which the substrate is made has
a dielectric constant or relative permittivity .epsilon..sub.r of
between 3 and 4. This ensures that optimum transmission of the
electrical signals applied to one sensor surface to the other
sensor surface can take place.
[0014] To make the capacitive proximity sensor according to the
invention as flat as possible, the sensor surfaces can be disposed
in a single plane. This makes it even easier to integrate the
capacitive proximity sensor into a component feeding device.
[0015] The sensor surfaces are implemented in a meander or
interdigitated pattern, thereby increasing the capacitance of the
capacitive proximity sensor and therefore improving its
sensitivity.
[0016] It is also possible to implement the capacitive proximity
sensor symmetrically about an axis of symmetry, one sensor surface
extending over the entire capacitive proximity sensor and at least
another two sensor surfaces being provided which are symmetrically
disposed relative to one another about the axis of symmetry.
[0017] The capacitive proximity sensor according to the invention
is particularly suitable for detecting component tapes or
components in the component tapes or splicing elements connecting
component tapes, as the combination of the low dielectric constant
of the sensor's substrate material and the spatial arrangement of
the sensor surfaces on the substrate provides millimeter range
detection for component tapes. The dielectric constant is
specifically between 3 and 4 and the detection distance is between
0.1 and 25 mm.
[0018] The sensor can be adapted to suit the type of component
tapes to be detected by varying these two parameters, i.e. the
dielectric constant of the substrate material on the one hand and
the spatial arrangement of the sensor surfaces on the other.
[0019] By implementing the sensor surfaces in an interdigitated
comb or meander pattern on the substrate, the capacitance of the
sensor can be maximized, thereby increasing the sensitivity.
[0020] In an axially symmetrical embodiment of the sensor with
three sensor surfaces, a first sensor surface being disposed facing
both the second sensor surface and the third sensor surface,
differential detection of the objects to be detected, such as
component tapes, components and/or component tapes splicing
elements, is possible. This enables environmental effects such as
atmospheric humidity, temperature and pressure to be eliminated
from the measurement result. In addition, it is also possible using
sensors which are suitable for differential measurement to detect
the direction in which the objects to be detected pass the
sensor.
[0021] In this differential embodiment, the sensor surface disposed
facing the other two sensor surfaces in particular can be connected
to a ground terminal through which a reference potential is applied
to the sensor which improves the elimination of disturbance
variables.
[0022] Particularly suitable is a sensor which is essentially
implemented twice as long as the objects to be detected in the
longitudinal detection direction.
[0023] According to the invention a component feeding device is
also created which has a sensor according to the invention, said
sensor being disposed in close proximity to the pick-up position.
The sensor can be integrated, for example, in the feeding channel
in which the component tapes are guided. In addition, there can be
provided an evaluation device by which the output signal of the
sensor can be e.g. digitally processed. It is also possible for the
evaluation device to be constituted by a microcomputer present in
the component feeding device.
[0024] The component feeding device according to the invention can
be implemented in such a way that the coupling elements used or
suitable for joining component tapes can be connected to ground
during detection of said coupling elements, thereby making a more
precise measurement possible.
[0025] According to the invention there is also created a method
for detecting component tapes by means of a feeding device
according to the invention, whereby an electric field is applied to
the sensor surfaces of a capacitive proximity sensor according to
the invention, the applied field is detected using the capacitive
proximity sensor and the detected field is analyzed by an
evaluation device. On the basis of the analysis result of the
evaluation device it is determined whether an object is present
between the sensor surfaces.
[0026] It is thereby possible, by analyzing the detected field, to
distinguish between different objects to be detected, such as
components, component tapes, blanks or gaps in component tapes
and/or splicing elements for joining two component tapes, as the
different objects to be detected also cause different changes in
the field detected compared to the electric field applied.
[0027] If a symmetrically designed capacitive proximity sensor is
used, it is additionally possible to perform a differential
measurement, as claimed, for example, in claim 20, in which
disturbances such as variations in atmospheric pressure,
temperature or humidity can be taken into account when analyzing
the detected field, thus providing a more accurate measurement
result.
[0028] Using the component detection device according to the
invention it is possible to detect, in a contactless manner by
means of an electromagnetic sensor, components which are being
transported by means of component feeding devices in a feeding rail
to an unloading point of the component feeding device, or splicing
elements joining component tapes to one another, said
electromagnetic sensor being linked to a control device. A signal
is emitted by the control device if the number of components in the
feeding channel falls below a predetermined minimum number or the
splicing element is detected.
[0029] The electromagnetic sensor can be a coil, for example. It is
possible to dispose this coil under the feeding channel. In
addition, the control device can have an excitation device which
can bring the coil into resonance with the feeding rail if the
number of components in the feeding channel falls below the
minimum. This allows particularly sensitive detection of components
in the feeding channel in a contactless manner. The components
present in the feeding channel are taken into account when
resonance is produced in the coil. If the number of components in
the feeding channel falls too sharply, the conditions for resonance
cease to be present, and the corresponding signal is emitted by the
control device.
[0030] It is also possible to select the conditions for resonance
of the coil in such a way that resonance obtains if the minimum
number of components is present in the feeding channel.
[0031] The coil can be, for example, an elongated flat toroidal
coil disposed along the feeding device.
[0032] However, a plurality of potential surfaces disposed under
the feeding channel can also be used as the sensor, any variation
in the voltage present between the potential surfaces being
detected by the control device. On the basis of the voltage
variation it is possible to evaluate whether the number of
components in the feeding channel has fallen below the minimum, the
components being detected on the basis of their dielectric
properties. The potential surfaces can be successively disposed,
for example, under the feeding channel in a well in the feeding
rail in the feeding direction. It is also possible to implement the
potential surfaces facing one another in an interdigitated manner,
so that a rectangular or curvilinear meander-shaped interspace
remains between the potential surfaces.
[0033] In addition, the electromagnetic sensor can be disposed on
two different sides along the feeding channel, both the upper and
lower side of the feeding channel as well as an arrangement along
the lateral surfaces of the feeding channels being possible
options. It is also possible to dispose the electromagnetic sensor
on two different adjacent sides along the feeding channel.
[0034] The component detection device according to the invention
has a feeding rail. In the feeding rail there is provided a recess
which is used as the feeding channel for the components. The
feeding channel is provided with a cover except at an unloading
point so that a component delivered to said unloading point can be
removed from the feeding rail by means of a handling device, the
components being transported along the feeding rail in the feeding
direction e.g. by means of a tape or directly in the feeding
channel.
[0035] A sensor is mounted below the feeding channel. This sensor
can be disposed, for example, in a cutout in the feeding rail. The
sensor extends in the feeding direction below the feeding
channel.
[0036] For example, an elongated flat toroidal coil can be used as
a sensor. According to the invention, this toroidal coil is linked
to a control device (not shown). The toroidal coil can be brought
into resonance under the feeding channel in the feeding rail by the
control device.
[0037] As the triggering event for the emission of a signal, it is
possible to evaluate not only the event of the onset of resonance
of the oscillatory system comprising sensor and feeding rail as
well as feeding rail cover and the components in the feeding
channel, but also the event of the discontinuation of resonance of
this system by means of the control device. On the basis of the
triggering event, the control device can output the signal
indicating that the number of components in the feeding channel is
less than a predefined minimum.
[0038] It is also possible to use a capacitive sensor as the
sensor, two or more potential surfaces being disposed below the
feeding channel to provide said sensor. By means of the control
device, steady-state voltages or predetermined oscillations are
impressed on these potential surfaces and the voltages or
oscillations present on the potential surfaces after application or
impressing are simultaneously detected. From the difference between
the impressed voltage or oscillation and the detected voltage or
oscillation it is possible to determine whether a sufficient number
of components are present in the feeding channel. For this purpose,
for example, a predetermined minimum difference between the
impressed signal and the detected signal can be specified. It is
also possible to detect changes, particularly capacitance
variations which are attributable to variations in permittivity in
the measurement field or space of the sensor. This is the case, for
example, when components and/or splicing elements pass through the
sensor's measurement field.
[0039] The arrangement according to the first preferred embodiment
of the invention is also suitable for use with an ultrasonic sensor
as the sensor for the component detection device according to the
invention, said ultrasonic sensor being disposed at the location
shown in the figure under the feeding channel of the feeding rail.
The ultrasonic sensor can be tuned, for example, to a
component-filled feeding rail or feeding channel or to an empty
feeding channel. The reflection of the sound waves in the
ultrasonic range is varied by the presence or absence of the
components. Using the control device it is possible to analyze this
variation and, if the number of components is less than a
predetermined minimum in the feeding channel, to emit the
signal.
[0040] A second preferred embodiment of the component detection
device according to the invention differs from the first preferred
embodiment in that sub-sensors are disposed on two different sides
of the feeding channel, the different sides of the feeding channel
possibly being opposite sides as well as adjacent sides of the
feeding channel. This embodiment according to the invention is
particularly suitable for using a plurality of potential surfaces
and as a capacitive sensor for detecting components, as this
arrangement between the sub-sensors and/or the potential surfaces
provides a more homogeneous field distribution than that provided
by the first preferred embodiment of the component detection device
according to the invention.
[0041] A third preferred embodiment of the component detection
device according to the invention differs from the second preferred
embodiment of the component detection device according to the
invention in that at least one of the two sub-sensors is comprised
of more than one piece on one side of the feeding channel. This is
implemented in the third preferred embodiment of the component
detection device according to the invention by a four-part
sub-sensor disposed below the feeding channel. Compared to the
sensor types described above, this embodiment lends itself
particularly to the use of a magnetoresistive sensor. For this
purpose there is disposed in the cover of the feeding channel a
permanent magnet or a field coil, for example, by which a magnetic
or electromagnetic field can be generated. In the feeding rail
there is disposed a plurality of Hall sensors which detect the
changed flux density of the field generated by the permanent magnet
or field coil in response to the components moved along the feeding
channel. The Hall sensors are linked to the control device to
enable the detected field variation to be analyzed so that the
signal can be emitted by the control device if the number of
components in the feeding channel falls below a predetermined
minimum number.
[0042] With the third preferred embodiment of the component
detection device according to the invention it is also possible to
dispose a single Hall sensor under the feeding channel in the
feeding rail.
[0043] This component feeding device according to the invention has
a framework. Disposed on said framework is a feeding rail as
described in greater detail above in connection with the
embodiments of the component detection device according to the
invention. The feeding rail basically extends from an unloading
point at which components 200 transported along the feeding channel
in the feeding direction can be removed from the component feeding
device by a handling device, the components being supplied from a
magazine which is disposed in a magazine housing of the component
feeding device according to the invention. The sensor of the
component detection device according to the invention is preferably
disposed under the feeding channel in the proximity of the
unloading point for the components of the component feeding device
according to the invention. However, the other arrangements for the
electromagnetic sensor explained in connection with the different
embodiments of the component detection device according to the
invention are also possible.
[0044] One embodiment of the electromagnetic sensor according to
the invention is particularly suitable for capacitive detection of
components or splicing elements in the feeding channel. For this
purpose the sensor has two sub-sensors which are essentially
disposed facing one another in an interdigitated pattern so as to
leave a meander-shaped interspace in one sensor plane between the
sub-sensors. Because of the intermeshing of the two sub-sensors,
the sensor is very sensitive to permittivity variations in its
vicinity. The sensor is therefore suitable for sensitive detection
of tiny components in the feeding channel.
[0045] The common feature of all the embodiments according to the
invention is that, in order to detect components in the feeding
channel of a component feeding device, no openings need to be
provided in the feeding rail or feeding rail cover to enable
components to be detected in said feeding channel. This is
advantageous particularly in the case of small or very small
components, as the openings for these components can only be
manufactured with the required precision at very high cost.
[0046] The invention will now be described in greater detail with
reference to the accompanying drawings, in which:
[0047] FIGS. 1a and 1b show a first embodiment of the capacitive
proximity sensor according to the invention,
[0048] FIGS. 2a and 2b show a second embodiment of the capacitive
proximity sensor according to the invention,
[0049] FIGS. 3a and 3b show further embodiments of the capacitive
proximity sensor according to the invention,
[0050] FIG. 4 shows an axially symmetrical embodiment of the
capacitive proximity sensor according to the invention, and
[0051] FIG. 5 shows a further axially symmetrical embodiment of the
capacitive proximity sensor according to the invention.
[0052] For all the embodiments of the invention, two or more sensor
surfaces are for example etched onto a substrate such as FR4 or
printed circuit board material. The substrate in conjunction with
the sensor surfaces forms a capacitive sensor or a capacitive
coupling element. The sensor according to the invention is simple
and inexpensive to manufacture, easily contacted electrically and
can be integrated or mounted for example in a tape channel of a
feeding module for placement systems on the upper or and/or lower
side. For example, to detect the splice between two component
tapes, the sensor according to the invention is made approximately
as wide as the component tape sprocket holes 210 used to transport
the component tape by means of a pin wheel whose pins engage in the
holes 210. The sensor is disposed for example below or above the
position of these holes 210 in the tape channel of the feeding
module. As soon as a splice at which a splicing element is located
passes the sensor according to the invention, either data
transmission between the sensor surfaces of the capacitive
proximity sensor according to the invention is disturbed or an
oscillator connected to the transmitter surfaces of the capacitive
proximity sensor is influenced.
[0053] To perform analysis, an evaluation device is provided which
can be designed as a discrete circuit and/or can be implemented by
means of programming in a computer present in the feeding module or
in the placement system. For the analysis, the type of material of
the object to be detected is essentially irrelevant. It is merely
necessary for the material of the object to be detected to have a
different relative dielectric constant than that of the component
tape material.
[0054] It would also be possible by this means to detect the end of
a component tape. The tape end can also be detected by disposing
the sensor outside the feeding module at another part of the
placement system and guiding the tape past the sensor so that the
end of the tape can be detected. FIGS. 1a and 1b show a preferred
embodiment of the inventive capacitive proximity sensor 110 and its
arrangement relative to a tape channel of a feeding device (not
shown) for component tapes 310, 320, the sensor 110 according to
the invention having two sensor surfaces each of interdigitated
comb design and with the teeth facing one another so as to leave a
clearance between the teeth in each case. The sensor surfaces of
the sensor 110 are disposed on a substrate (not shown) in this
manner. FIG. 1a illustrates the position of the sensor 110
according to the invention relative to a component tape 200 that
can be transported in the tape channel 310, 320 of the feeding
module. The component tape 200 has sprocket holes 210 along its
longitudinal direction, and component pockets in which components
240 can be accommodated.
[0055] As shown in FIG. 1b, the inventive capacitive proximity
sensor 110 is disposed in the lower section 320 of the feeding
channel 310, 320. This enables in particular components 240 in the
component tape 200 to be easily detected. It is also possible to
dispose the sensor 110 above the component tape 200 on/in the
feeding channel 310, 320.
[0056] FIGS. 2a and 2b illustrate an embodiment of the capacitive
proximity sensor according to the invention which is suitable for
detecting splicing elements 230 used to join two component tapes
200, the inventive capacitive sensor 120 being disposed in the
region of the sprocket holes 210 of the component tape 200 on the
upper side 310 and/or the lower side 320 of the tape channel of a
component feeding module, as the splicing element 230 is also
mounted on the sprocket holes 210 of the component tape 200. This
provides easy detection of the splicing element 230 by means of the
inventive capacitive proximity sensor 120 according to this
embodiment.
[0057] FIGS. 3a and 3b depict further embodiments of the sensor
surfaces of the capacitive proximity sensor according to the
invention. FIG. 3a shows an embodiment wherein a plurality of
parallel sensor surfaces are disposed one after the other in the
longitudinal direction of the component tape 200, said sensor
surfaces of the sensor 130 each being connected alternately in the
transport direction of the component tape 200 to one of two
connecting leads of the sensor 103 so that, viewed in the transport
direction of the component tape 200, one or more bar-like sensor
surfaces disposed crosswise to the transport direction are provided
with alternate sensor connection or polarity.
[0058] FIG. 3b shows an inventive capacitive proximity sensor 140
provided with two sensor surfaces which extend parallel to one
another in the transport direction of the component tape 200 over a
plurality of sprocket holes 210.
[0059] FIGS. 4 and 5 depict axially symmetrical sensor surfaces of
a capacitive proximity sensor according to the invention. The
embodiment of the invention according to FIG. 4 has an axially
symmetrical capacitive proximity sensor 150. This has a first
sensor surface 151 extending in a first direction over
approximately the entire length of the sensor 150. The first sensor
surface 151 is symmetrical about an axis perpendicular to the first
direction. It has an interdigitated or comb-like structure, the
teeth or fingers essentially pointing in a second direction
perpendicular to the first direction.
[0060] The capacitive proximity sensor 150 shown in FIG. 4 is
additionally provided with a second sensor surface 152 and a third
sensor surface 153 which are likewise of interdigitated or
comb-like design and disposed symmetrically about the axis of
symmetry of the sensor 150 in such a way that the fingers of the
second sensor surface or the fingers of the third sensor surface
are disposed facing those of the first sensor surface. This
produces a meander-shaped interspace between the fingers or teeth
of the first sensor surface and the second sensor surface or third
sensor surface. This structure is particularly suitable for
differential detection of components and/or splicing elements. The
measuring result can be improved still further by electrically
connecting the first sensor surface 150, as illustrated in FIG. 4,
to a reference potential.
[0061] In the embodiment of the capacitive proximity sensor 160
depicted in FIG. 5, a structure similar to that shown in FIG. 4 has
been selected. However, the first sensor surface 161 of the sensor
160 has two interdigitated or comb-like extensions in and counter
to the first direction of extension which are spaced facing one
another crosswise with respect to the direction of extension.
Within the interspace of the extensions of the first sensor surface
160 which are disposed in or counter to the first direction there
is disposed a second sensor surface 162 and a third sensor surface
163. The second sensor surface 162 and the third sensor surface 163
are implemented and disposed symmetrically about the axis of
symmetry of the sensor 160. They have a bar-like structure with
interdigitated or comb-like extensions essentially perpendicular to
the first direction of the capacitive proximity sensor 160 in such
a way that a meander-shaped interspace is left between the second
sensor surface and the first sensor surface 161 and between the
third sensor surface 163 and the first sensor surface 161 in each
case.
[0062] For all the embodiments of the invention it is advantageous
to dispose the sensor surface essentially in one plane.
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