Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates to a display or ind;~t3~g2 ~/
device using a disk having contrasting opposite sides for
selective display, in a viewing direction for use in displays
or indicators, and utilizing at least one optic fibre end which
is displayed to the viewing location in one ~isk orientation~
which, in most embodiments corresponds to the display in the
viewing direction of the lighter side of the disk. lhe view;ng
direction coincides with intended viewing locations. In onq
alternative of the present invention the disk is designed to
obscure a single fibre encl ir. the other position of the disk.
In another alternative of the invention there are two fibre
bundle ends and one will be displayed and one obscured in each
position of the disk. In the latter alternative the color of
the light emitted by each fibre end will be chosen having regard
to the color of the side of the disk simultaneously displayed.
The term 'disk' herein defines a relatively flat body
defining a median plane. It need not be circular. In preferred
aspects herein the disk is elongated with parallel sides and
preferably rounded ends.
By the term 'optic' fibre herein is included a single large fibre or a
bundle of fibres arranged: at one e~ld~to receive light fro~ a source,
to conduct light to the vicinity of the disk described herein.
In this application there is no discussion of the disk-remote
end of the fibre or the source of illumination, both of which
may be conventional.
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'Forward' herein is from the device toward the
intended ~iewing location and 'rearward' is in the opposi~e
direction.
The type of display device with which the invention
is concerned provides a disk orpattern area from an array of
disks for viewing from a viewing location which is at the centre
o~ possible viewing positions whose locus is a cone with its
apex at the disk or pattern area. The cone need not be a
surface oE revolution although it usually will be. The subject
display or in~icating device will be adapted to rotate about
180~ between limiting positions to display a contrasting pattern
areas to the vie~ing location in two limiting positions of disk
rotation. In the main embodiment the disk will display a light
side in an ON limiting position and a dark side in an OFF lirniting
position and in the ON position the light side will be visible
due to reflected ambient light. In addition in the ON position
the disk or pattern area will be adapted to allow the light
from an or optic fibre to supplement the reflected
ambient light.
Such a device is disclosed in European Patent Application
86,401,583.9 filed July 16, 1986, Publication number 0,210.913.
(application '913 hereafter)~ In application '913 a electro-
magnetically driven disk rotates on its diameter to display a
brighter or a darker side. An optic fibre end is placed behind
the disk which is apertured so that in its 'ON' attitude the
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light from the fibre shines through the disk to augment the
effect of the reflected ambient light~ while in the 'OFF'
attitude of the disk the disk or an appendage thereo~ masks
the fibre to viewers. A disadvantage of the apertured disk
was that, if near 180~ rotation was used, the fibre must be
at least the radius of the disk rearward of it, meaning that
the cone of light from the disk was very small or the aperture
must be too large reducing the disk's ambient light reflectant
area. If substantially less than 180~ rotation was used special
appendages to the disk had to be provided to mask the fibre to
the viewer in the OFF position.
Patent 5,055,832 (Patent '832 hereafter) dated October
8, 1991, and commonly owned with this application overcomes the
specified disadvantages of application '913 by providing a
contrastingly colored disk rotatable through approximately 180~
and provided with a radially inwardly directed notch extending
in from a peripheral edge to a location near to but on one side
of the disk axis. When the lighter side of the disk was displayed
~; the fibre shone through the inner end of the notch to attract
the viewer's attention. When the darker side of the disk was
displayed, the fibre end was obscured by an area of the disk. The
described arrangement of the notch could be used because the
permanent magnet, rotatable with the disk, and driven to cause
such rotation, was located at one axial end of the disk, so that
the drive core did not tend to interfere with disk rotation nor
did automatic winding techniques used for winding the energizing
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CA 02087234 1998-02-16
coil for the drive coil, tend to interfere with the fibre or its mount, thus allowing the use of the
centrally directed notch.
However other disks are driven by a pair of cores having ends displaced transversely
relative to the pivotal axis and acting on a magnet within the plan view area of the disk itself to
rotate the disk through approximately 180 . The construction required that the one edge of the
disk, approximately midway axially therealong, to rotate past the core and core mounts between
limiting positions. An example ofthis is shown in U.S. Patent 4,577,427 dated March 25, 1986
(Patent '427 hereafter) and commonly owned with the present application. Since one edge of a
disk driven by two cores had to be notched to allow the disk to rotate past the cores and core
mounts, and since the automatic winding techniques were desireable for the cores, a spacing was
required between the core and the optic fibre. Thus the nearly centrally directed notch could not
10 be used.
By 'axial end' of the disk it is assumed that the disk dimensions may be referred to as
'axial, width and thickness' instead of the usual 'length, width and thickness' and 'axial' means,
measured parallel to the disk pivotal axis.
This invention therefore provides a disk rotatable about 180 between two limiting
.
posltlon wherem It dlsplays,
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respectively, its contrasting sides to a viewing location.
An optic fibre is located to be near the ou~side edge of the
disk and rearward thereof in one of the disk's limiting
positions and, near such edge, at one axial end of the disk.
The disk is shaped to obscure such fibre end (to the viewing
location) in one (usually the O~F) position of the disk. On
the opposite side of the disk axis at a location being the
mirror image, across the disk axis, of the disk area which
obscures the fibre end, is a cut out forming a continuation
of the edge of the disk what allows the disk, rotating in
either direction between limiting positions to pass the fi.bre
and its mount or support. Since the cores are no closer than
midway along the axis of the disk and the fibre is at one end,
there is sufficient spacing for automatic winding of the cores.
The 'corner' location of the cut out at one axial end
of the disk and at maximum spacing from the axis has advantages
beyond good spacing from the core.
The notch for passing the fibre mount is to be made
as small and preferably as far from the center as possible since
it derogates from the display area and hence the appearance of
the disk. For minimum notch area the notch is preferably
defined by one edge parallel to the rotational axis. The other
edge is preferably about 90~ thereto. If the pivotal axis of
the disk is at an angle to the perpendicular to the fibre optic
axis the transverse edge will or may be angled to be slightly
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above or below 90~.
Preferably for a number of applications, such as bus
signs the disk is made longer in the axial than in the radial
direction as best shown in patent "~27.
When the non-notched edge of the disk is covering the
fibre end the lighter side of the disk ~aces the fibre end.
Reflection of the light of the fibre, back from the disk rnay
with some disk backgrounds create random light reflections for
the viewer and derogate from the appearance of the indicator
or display. The area on the lighter disk side, which receives
the disk radiation is therefore sometimes darkened to absorb
the light and absorb such random reflections. This is a
reduction of the area of the bright side of the disk which may
be tolerated in some applications.
The permanent magnet is preferably mounted, within
the periphery of the disk in plan view. The magnet is preferably
mounted so that in each limiting position one pole of the magnet
rests close to one of the drive cores. Although the magnetic
force, between the permanent magnet and the drive core will,
at adequate spacing, vary inversely as the square of the distance
between them, there is a lower limit to the proximity to which
the magnets may be brought. This is because, with the cores
used (althou~h they are of reiatively hi~h r~m~n~nre) the permanent disk
magnet, at a certain proximity, will overcome the core magnetism
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and latch to the core. Ihus the spacing at a limiting position
must be sufficient to avoid this. (For the wide variations of
core materials and consequent remanent magnetism, and the wide
variety of permanent magnets and spacing this distance must be
empirically determined). For tolerance control purposes the
spacing once determined should therefore be maintained by a
projection of the core mount (not the core itself to avoid
bringing disk layer thickness into the calculation). For
tolerance control purposes, the fibre end shollld not be used as
a stop. ~lence a means must be provided for locating the fibre
end rearward of the disk in that limiting position where the
disk area obscures the fibre.
In drawings which illustrate a preferred embodiment
of the invention.
Figure 1 is a perspective vie~ from the front of
display or indicator elements in accord with the invention.
Figure 2 is an end, partially sectional~view of an
element of Figure 1.
Figure 3 is a rear perspective view of a strip of
display or indicating elements as shown in Figure 1.
Figure 4 is a partial side view of the ele~ents of
Figure 1 with some components missing.
Figure 5 is a partial end view showing the relation
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of the magnetic members.
Figure 6 is a sectional side view showing the
relative location of the fibre end to the other components.
Figure 7 demonstrates the insertion of a fibre
bundle in its mount.
Figure 8 demonstrates the geometry of the cut-out.
Figure 9 shows a perspective view from the front of
elements each with two fibres.
Fi~ure 10 and 11 show schematically the disk of Figure
9 in respectively contrasting orientations.
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Figure 1 shows the frame 10 running longitudinally
along direction L and such frame at each end, in the preferred
embodiment, is provided with rneans defining mounting grooves
12 which allow a plurality of frames 10 to be mounted side by
side on transverse coupling members received in grooves 12, to
form an array. The transverse direction is indicated by lines
T - T. An analogous method of mounting longitudinally extending
display frames is shown in U.S. Pat. No. 3,942,274 dated Mar.
9, 1976 to Winrow although, in that patent, the transverse
grooves are forwardly directed.
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~ It will be understood that the letters L, T, define
- a display plane in such a device and that the perpendicular P
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to such plane (Fig. 6) ls directed toward the viewing location
and is the reverse of the intended viewing direction. When
speaking of intended viewing clirections and locations it must
be realized that these are in the centre of a cone of viewing
positions which will vary in various applications where within
such cone the display or indicator is clearly displayed.
It will also be noted that in the preferred (but not all) applications.
the disks are at an angle A to the intended viewing direction so that their pivot
axes may overlap. Ihis angle would normally ~e between 3~ and
10~ but will be selected to be small enough so that the disk
faces may be seen from the intended viewing location. For
example if the elements were on a sign over a freeway, the
intended viewing direction for a car driver might be at 5~
above the horizontal. Thus the di.rection P and the direction of
the optic fibres would be at a descending angle of 5~ to catch
the eye of the motorist while the angle A~ would be (say) 3~
below this.
In the drawings, the frame 10 defines transverse walls
14 at each end and located between adjacent ones of the
longitudinally disposed disks 16. Each transverse wall 14 is
provided with a forwardly directed mounting projection 18.
Adjacent mounting projections 18 are provided with facing wells
20 to receive the disk 16 spindles 22. As best shown in Fig. 4
the facing wells 20 of adjacent projections 20 are displaced in
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the forward direction to til~ the disk pivot axis to the
vertical a sufficient degree so that the wells 20 on opposite
sides of a projection 18 overlap in a vertical direction (that
is are laterally displaced frorn each other relative to the
row direction). The wells, as previously explained will
normally be displaced to produce an angle A of the spindle axes
to the vertical of about 3~.
In the preferred form of the invention the disk is
of the type disclosed in U.S. Pat. Nos. 3,87~,945 ('945 here-
after) dated Mar. 18, 1975 and (its divisional) 3,953,274 ('3274
hereafter) dated April ~7, 1976, both commonly owned with this
application and both naming as inventors Winrow et al. The disk
is thus made of 3 layers laminated together, the middle layer
- is apertured in the shape of and to receive a magnet of
approximately the thickness of such middle layers. It will be
;~ obvious that this method of construction allows the preferred
assymetric dispositlon of the magnet to the extent desired with-
out inconvenience since the middle layer is merely punched at
the selected location and the magnet inserted during the
construction of the disk. In the patented construction, moreover,
the middle layer is shaped to provide projecting spindles which
form the mounting spindles of the disk. (It should be noted
that each of the outer layers may have sub-layers. The outer layer
; ~IJI .~~ tot~ ~rkside is usually dark tape thereover to produCe
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the dark outer surface on the ultimate cl:isk. The opposite
side of the disk wlll customarily have a sub-layer of vinyl
colored to the bright color required and sub-layer being an
outer transparent protective casing. In general however the
disk is assembled as a three layer la~lination, the rnyler-dark
covered sub-layers being applied as a single layer to one side
of the central layer and the vinyl-protective coverirlg sub-layers
being applied as a single layer to the other side of the central
layer.
Although the inventive aspects defined herein are
suited to the previously patented laminar disk, it must be
emphasized that in the broad aspects of the invention, including
the aspect of tilting the disk axes relative to the row axes
and the aspect of stopping the disk with a contact inward of
the disk edge are not limited to use of the patented disk.
The disk 14, preferably constructed as defined in U.S.
Patents '945 and '3274 comprises a lamination of three layers.
Each of the two layers 24 and 26 may be made from two sub-
layers. The light side layer 24 is usually an inner sub-layer
of vinyl colored for the light color designed with an outer
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transparent protective sub-layer. The dark side layer 26 is
usually a single layer of tape to pro~ide the dark color. The middle layer
28 is preferably of mylar to correspond to that of the magnet 30. The mylar
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la~er has s~lfficient strength that it supports the extending
stub shafts 22 which are formed as an integral part of the
middle layer. The stub shafts 22 may be inserted in wells
20 by slightly bending the resilient (due to the resiliency
of the mylar) disk to achieve insertion.
As best shown in FIG. l the middle layer 28 is
provided with a slot shaped to receive the permanent magnet
30 which is preferably made of the copper nickel-iron alloy
cunife magnetized to provide a magnetic axis in the med:ian
plane of the disk transverse to the pivot axis defined by
spindles 20. The poles '~' and 'S' of the permanent magnet
are indicated in the drawings.
The recess in the middle layer 28 of the disk and
the magnet therein are preferably located so that it is
transverse to the pivotal axis and displaced to be all on one
side of the pivotal axis at about the midway point between the
stubs 22. On the edge opposite the outer (here 'N' pole of
~ the magnet) is provided a notch 36 for a purpose to be hereafter
- discussed.
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The disk is preferably made longer than it is wide
to take advantage of the fact that in many applications, such
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as bus signs, there is more available space in the vertical
than in the horizontal dimension so that the height of the disks
is increased to give greater visibility.
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The shape of the disk is a compromise. An oval disk
terMinating in semicircles at each end would give a better
visual impression than a rectangle for disks collectively
defining a diagonal. However, the oval disk does not use as
much of the available display area as desired. Therefore, the
compromise shape with c-lrved end and corners as shown is used.
As noted the use of overlapping wells and angled
spindles allows more complete use of the available display
space in a row by allowing the disks to be placed more closely
together.
Actuation for the disk to turn it to one or the other
orientation is provided by a reversible magnetic field forming
means, exterior to the disk and acting on the permanent magnet
30. The exterior field forming means in the preferred embodiment
is provided by a pair of core members 38 of high carbon, steel,
having a relatively high remanence. The core members 38 are
fixed in position on each side of the frame and extend through
bores therein to project rearwardly of the frame, as shown and
forwardly to the vicinity of the disk (and magnet) locus when
the disk is displaying one or the other of its contrasting sides
in the viewing direction. The molded plastic frame provides
on each side inwardly facing abutments 40 each of which partially
surrounds a core 38 adjacent the core forward end. As shown in
FIG. 2 the forward end of each abutment 40 has a forwardly and
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inwardly sloping surface which is located forward of the
forward end of core member 38 and provides a pair of stops
or knuckles ~2 shaped to contact the disk 16 inwardly of
its edge. The disk contacting surface of the knuckles or
stops 42 is as small as possible in humid conditions surface
tension will ~old the dot in place if the contact area is
too large.
The contact is made inwardly of the clisk 16 edge
because the construction of the disk sometimes leaves a small
(not visible) accretion of adhesive or tacky material at the
edge. The inwardly displaced contact does not contact such
material and the risk of the disk sticking is therefore reduced.
A knuckle 42 stops the disk at a limiting position
which is a location spaced from the core 38 end because it is
preferred to use high carbon steel for the pole pieces. This
;~ material, although of relatively high remanence is of lower
remanence than some core materials (such as vicalloy) previously
used in controlling display disks. With the high carbon steel
cores 38, therefore, care must be taken that the spacing between
the ends of cores 38 and the permanent magnet 30 of the disk is
such that the permanent magnet cannot alter the magnetic
polarization of the core 38 and to cause latching of the disk.
Accordingly, knuckles 42 are shaped to achieve the desired
spacing which will be determined in accord with the cores 38
'~ and magnet 30 used~
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The disk opposite magnet 30 is provided with the
notch 36 shaped to clear core 38 and abutment 40 during
rotation of the disk.
It should be noted that, although the spacing of
the core end from the magnet in stopped position is irnportant,
this is customarily achieved by measures exterior to the disk.
Preferably during assembly the frame 10 is rnaintained in a
clamp while tooling associated with the clamp inserts the
cores to a stop intrinsic to the tooling and clamp. The core
38 is then held in place by friction.
In accord with the novel features introduced by this
invention the optic fibre arrangement in the device will now
be discussed. With the exception of the core notch 36 and
the fibre cut-out 110 the disk is preferably sy~metrical about
the pivotal axis.
The cut-out 110 is located on the same edge as notch
36 and as far as possible from the core notch 36 and is thus
located at one axial end of the disk. Thus if the disk were
square or rectangular, both of which are within the scope of
the invention the cut-out 110 would be located in a corner of
the disk and the position shown is analogous to the corner
given the disks rounded ends.
~ A bore 114 in the rear wall of casing 10 is continued
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on each side of the rear wall in a forward boss 116 and a
rearward boss 118. Since the direction of the ~~ic fibre is quite important,
the bore 114 is a close ~it for the fibre ferruLe. rLhe optic fibre 122 (which is
itself a lar~e bundle of tiny fibres) or may be a single large fibre particularlY
ifof plastic with suitableoptic qualities is covered by a plastic protectlve
sheath 123 and extends from a ]ight source, not shown, to
a metal ferrule which encloses the bunclle leaving its radiation
output end 128 open. The ferrule comprises a wider rearward
cylinder 126 and a narrower Eorward cylinder 12~, defining
between them the forwardly facing shoulder 130. The t'hinner
cylinder 124 makes a friction fit with the walls of the bore
114 and the outer wall 132 of the rear 'boss acts as a stop
for shoulder 130 to deterr,1ine the location of the output fibre
end 128. The location of fibre end 128 is not particularly
; critical but (to avoid acting as a stop for the disk) it must
be rearward of the area 13~ (which is a mirror image of the
cut-out 110 across the pivotal axis) when area 13~ 'blocks the
light from the fibre end 128 in the OFF limiting position.
Fibre end 128 must be then rearward of the disk because
disk magnet 30 to core 38 spacing is critical and this is
determined by stops 42 acting on the disk surface.
The GUt-out 110 is dimensioned to allow the light from
the fibre end to reach the viewing location in the ON limiting
position of the disk. The notch area is kept to a minimum
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because it detracts from the appearance of the dot in the ON
position. Thus in the preferred shape of the cut-out the edge
136 is parallel to the pivotal axis and the edge 138 is
approximately perpendicular thereto. If the display element
were to have the pivotal axis perpendicular to the viewing
direction a true perpendicular edge 138 would be used with the
location of edge 138 (as in the preferred embodiment) chosen
to clear the fibre optic and its support when travelling between
limiting positjonS, and in the ON position to al].ow passage
of the radiation from the optic fibre end in the desired cone
about the viewing direction. (In most cases the specified
cone for the optic fibre used has a 15~ included angle, that
is a surface of revolution 7 1/2~ from the intended viewing axis).
Where, as here, the pivotal axis of the disk slopes
at 3~-10~ to the plane L-T of the array, the edge 138 for a
cut-out in the top corner must slope at a little greater than
90~ (see Figure 8) to edge 136 to clear the fibre bundle and
mount, and if a lower corner fibre and cut-out were provided
than the edge 138 could be slightly less than 90~ to edge 136
and still clear the fibre end mount and allow passage of the
radiation cone from the fibre.
The mirror image area 13~ of the disk blocks the light
from the fibre from the viewer in the OFF position of the disk.
It is found that with certain finishes for the inside of frame
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10 a certain arnount of light from the fibre is sometimes
reflected from the lighter side of the disk and then randomly
reflected about the disk-wall in casing 10 so that some of
this radiation reaches the viewer with a consequent derogation
in ~he sign appearance. Accordingly the area 134 on the
lighter side of the disk, is preferably provided wi~h a
blackened absorbing coating to greatly reduce reflection. For
this purpose the further derogation from the disk appearance
in ON position because of the blackened area is accepted. For
specific purposes the blackened area may be larger or smaller
than cut-out 110.
Cores 38 project rearwardly of the frame and mount
energizing windings 46 which magnetize the cores in the desired
; polarity. The bridging member 48 of iron having soft magnetic
qualities is attached to the cores 38 rearwardly of windings 46
to complete the magnetic circuit between the cores 38. Terminal
posts 50 are mounted to project rearwardly from the frame
corresponding to each core 38 and designed at their rearward
end for connection to an electrical circuit, not shown. The leads
52 to the windings 46 are preferably soldered to terminal posts
50 at the latter's rearward end. The windings 46 are connected
in series so that energization to the paired terminal posts will
magnetize the paired cores 38 so that one core forward end is
r h and the other south. These polarities are simultaneously
reversed to rotate the disk.
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The windings ~6, and cores 38 are preferably wound
by automatic machinery requiring a minimum radius about each
core for the winding head. It is such radius that requires
that the boss 1]8 for the fibre be as far as possib'e from
the nearest core, in this case in the 'corner' of the disk for
a central core notch. This is also the reason why the cut-out
110 for the fibre cannot, in any preferred arrangement, be
combined with the core notch. The extended bosses 118 and 116
for the fibre ferrule are, in turn required to provide a degree
of accuracy to the radiation from the optic fibre.
In other constructions than the 'sandwich dot' of U.S.
patents '945 and '3274 the core could be at one axial end of the
disk and the fibre and fibre notch could be at the other axial
end of the disk. However with the sandwich dot, the magnet is
dropped in a well, to be surrounded with a sandwich layer so
cannot be too close to a corner.
The permanent magnet 30 is preferably a relatively
flat metal magnet made of cunife with its magnetic axis
and location as indicated. The lacation and orientation mean
that the radially outward pole 'N' in the drawing is the driven
element for operation of the device while the radially inward
pole takes no material part in the operation.
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In many applications it would be adventageous to
use a flat ~agnet with its polar axis perpendicular to the
plane of the disk. However metal magnets are not usually
suitable when so magneti~ed and plastic magnets may be so
magnetized but are too weak when used with the sandwich dot.
With the disk axes sloped, as shown in FIG. 4 the
assymetric arrangement of the disk, as shown in FIG. 1 aids
in the operation of the disk. As noted, with any of the disks,
a notch and cut-out removed from one side and the magnet is
displaced toward the other. The weight bias in favour of the
magnet displacement side together with the axia~ tilt assists
the disk to start to turn as soon as the core is reversed to
release at from a limiting position. This renders operation
of the disk more certain.
As illustrated in FIG. 5 the permanent magnet 30,
in its rest limiting position of FIG. 2 has its outer edge 31
(corresponding to the N pole) within a 45~ truncated core whose
axis is perpendicular to the disk rest position and which expands
from the core end in the direction of the disk. The location
of the outermost edge 31 of the permanent magnet is indicated
E the boundaries of the cone, as they appear in FIG. 5 are
defined as CR and CL respectively. It will be obvious that
the o~lter edge 31 of the permanent magnet is well within this
cone. The practical result is that on reversal of the core
magnetism the repulsive force from the core on the magnet is
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more nearly perpendicu]ar to the disk than parallel, giving
a good starting torque to the disk and avoiding the necessity
of providing an extra bias magnet. The cores 38 are of course
located so that the same effect occurs when the disk is in
i~s opposite limiting position to that shown in FIG. 2, that
is with the N end of the permanent magnet to the le~t and the
notch to the right. Obviously the geometrical relationship
will hold true where as shown the cores 38 are symmetrically
disposed with respect to the pivotal axis.
As previously noted the feature just described, and that
relating to the stop for the disk inboard of the disk apply
to disks used singly as well as to a plurality of disks in
rows; and both features apply to disks whether or not their
pivotal axes are perpendicular to the viewing direction or at
a slight angle to the perpendicular.
In operation the disk is rotatable approximately 180~
between its ON position (with the notch 36 and cut-out 110 to
the left in Figure 1) and OFF position with the notch and cut-
out to the right in Figure 1, rotation being in the sense which
moves the notch 36 and cut-out 110 farthest from the viewing
location, i.e. to the rear of the pivot axis. The cores are
magnetized as indicated in FIG. 2 (indicated by the dotted 'N'
and 'S'). The fibre ends 128 will each be constantly illuminated.
The disk would have rotated to and remained in the ON position
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of the middle disk in E'igure 1. The light from the fibre
shines through cut-out 110 to capture the attention of the
viewer within a cone about the intended viewing direction.
The lighter side of the disk will be displayed and will
usually correspond to the color of the fibre radiation. The
opposite darker side of the disk will usually correspond to
the color of the frame and associated hardware. When windings
46 are energi~ed to reverse the polarity of the cores the disk,
under the control of the radially outward here IN' pole of
permanent magnet 30 will rotate (counter-clockwise in Figure 2),
with the notch passing one then the other core 38 and its mount
and the cut-out passing the fibre top, 128 and ferrule 124
until the non-notched edge of the disk is resting on the left
hand stop 42. The disk is now in the OFF position with the
area 134 blocking, to the viewer, the light from the optic
fibre and the dark side of the disk displayed. The disk will
remain in that position until the polarity of the cores is
again switched, at which time it will again rotate to the ON
position rotating so that the notch and cut-out again pass
rearward and farthest from the viewer.
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In all aspects of the invention the polarity of
the permanent magnet may be reversed and the operations and
advantages will be the same, the positions of the disk being
obtained by opposite magnetizations of the cores.
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As an alt~rnative to the preferred embodiment
Figure 9 shows a second optic fibre with end 128A with
supporting boss 116A (aligned rear boss is not shown the
second fibre has a location at the opposite axial end of
the disk and the opposite side of the pivotal axis ~rorn fibre 128
with supporting bosses 116A (rear boss 118 is not shown)
from bosses 116, 118 with an additional cut-out llOA
to clear the fibre bundle and boss 116A. With this
arrangement, the disk will display one fibre 128 in one
limiting position and the other ~ibre 128A in the other
limiting position. Thus, for exaMple (Figure 10) one fibre
128 and its co-displayed side 24 may display red to the
viewer and in the other disk orientation (Figure 11) the
other fibre 128A and its co-displayed disk side 26 green.
The array background will have whatever color is most suitable.
The electromagnetic drive will be the same as that described
in relation to Figure 1.
The application has discussed the use of the disk
with a 'corner' notch for an optic fibre in terms of the
preferred disk form of patent '427. However many alternatives
are considered within the scope of the invention. As
previously stated the axes may be parallel to the array instead
of slanted as in patent '427. The axes may bear any orientation.
The magnetic drive may be different, for example on a magnet
or the end of the disk as in patent '832.
23-
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