U.S. patent number RE30,476 [Application Number 05/953,283] was granted by the patent office on 1981-01-13 for devices for the fold-free stretching and holding of liquid crystal films.
This patent grant is currently assigned to Bayer Aktiengesellschaft. Invention is credited to Friedrich Jennen, Hermann Linden.
United States Patent |
RE30,476 |
Jennen , et al. |
January 13, 1981 |
**Please see images for:
( Certificate of Correction ) ** |
Devices for the fold-free stretching and holding of liquid crystal
films
Abstract
A frame for holding and stretching liquid crystal films for
thermographic diagnosis of cutaneous and subcutaneous disorders. A
foil coated with the liquid crystal is held and stretched by the
frame. The frame comprises an .[.outer.]. .Iadd.inner
.Iaddend.member 1 which is secured to .[.inner.]. .Iadd.outer
.Iaddend.member 2 by clips 3 registering in openings 8. The frame
members are contoured so the stretching is effected without
formation of folds.
Inventors: |
Jennen; Friedrich
(Bergisch-Gladbach, DE), Linden; Hermann (Cologne,
DE) |
Assignee: |
Bayer Aktiengesellschaft
(Leverkusen, DE)
|
Family
ID: |
27185964 |
Appl.
No.: |
05/953,283 |
Filed: |
October 20, 1978 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
581323 |
May 27, 1975 |
|
|
|
Reissue of: |
703152 |
Jul 7, 1976 |
04079529 |
Mar 21, 1978 |
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Current U.S.
Class: |
38/102.2; 40/780;
160/380 |
Current CPC
Class: |
G01K
13/20 (20210101); G01K 11/165 (20130101); A61B
5/015 (20130101) |
Current International
Class: |
A61B
5/00 (20060101); G01K 13/00 (20060101); G01K
11/16 (20060101); G01K 11/00 (20060101); D05C
001/04 (); G09F 001/12 (); A47G 005/00 () |
Field of
Search: |
;38/102,102.1,102.91,102.2 ;160/378,380 ;350/16LC
;40/152,156,155,1R,125G |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lawson; Patrick D.
Attorney, Agent or Firm: Sprung, Felfe, Horn, Lynch &
Kramer
Parent Case Text
This application is a continuation of Ser. No. 581,323, filed May
27, 1975, now abandoned.
Claims
What is claimed is:
1. A device for the fold-free stretching and holding of liquid
crystal films, comprising a substantially rectangular outer frame
having an .[.external.]. .Iadd.inner .Iaddend.centering edge and an
insertable inner frame comprising an .[.inner.]. .Iadd.external
.Iaddend.centering edge, wherein the inner boundary of the
.[.inner.]. .Iadd.outer .Iaddend.frame is in the form of a
stretching collar, the surface of the collar facing the inner
.[.frame.]. centering edge being bevelled, the lower edge of the
stretching collar being rounded off and its surfaces being smooth,
the surface of the stretching collar facing away from the inner
.[.frame.]. centering edge being bevelled at a steeper angle than
that surface facing the inner .[.frame.]. centering edge, and
wherein the .[.outer.]. .Iadd.inner .Iaddend.frame comprises a
stretching groove which cooperates with the stretching collar and
the surface of the .[.outer.]. .Iadd.inner .Iaddend.frame directed
towards the .[.inner edge.]. .Iadd.stretching collar .Iaddend.of
the .[.inner.]. .Iadd.outer .Iaddend.frame is bevelled parallel to
the bevel of the stretching collar, the corners of the inner
.[.boundry.]. .Iadd.boundary .Iaddend.of the outer and inner
.[.frame.]. .Iadd.frames .Iaddend.being rounded off, the outer
frame being insertable in the .[.inner.]. .Iadd.outer
.Iaddend.frame by cooperation of the inner and external centering
edges and cooperation of stretching collar and stretching
groove.
2. A device as claimed in claim 1, wherein clips arranged on the
.[.inner.]. .Iadd.outer .Iaddend.frame engage in openings formed in
the .[.outer.]. .Iadd.inner .Iaddend.frame.
3. A device as claimed in claim 1, wherein a double adhesive tape
is arranged on the inside of the outer frame.
4. A device as claimed in claim 2, wherein a double adhesive tape
is arranged on the inside of the outer frame.
5. A device as claimed in claim 1, wherein said corners are rounded
with a radius of 20 to 25 mm.
6. A device as claimed in claim 4 wherein said corners are rounded
off with a radius of 20 to 25 mm.
7. A device as claimed in claim 2, wherein the clips are spaced
from and disposed outwardly of the .[.inner.]. .Iadd.outer
.Iaddend.frame stretching collar.
8. A device as claimed in claim 7, wherein the clips are disposed
intermediate the .[.inner.]. .Iadd.outer .Iaddend.frame stretching
collar and the inner .[.frame.]. centering edge.
9. A device as claimed in claim 6, wherein the clips are spaced
from and disposed outwardly of the .[.inner.]. .Iadd.outer
.Iaddend.frame stretching collar.
10. A device as claimed in claim 9, wherein the clips are disposed
intermediate the .[.inner.]. .Iadd.outer .Iaddend.frame stretching
collar and the inner .[.frame.]. centering edge.
11. A device according to claim 2, wherein said corners are rounded
off with a radius of 20 to 25 mm and the clips are spaced from and
disposed outwardly of the .[.inner.]. .Iadd.outer .Iaddend.frame
stretching collar.
12. A device as claimed in claim 11, wherein the clips are disposed
intermediate the .[.inner.]. .Iadd.outer .Iaddend.frame stretching
collar and the inner .[.frame.]. centering edge.
13. A device according to claim 1, the inner frame being inserted
in the outer frame, and a liquid crystal film being held in the
frame by being drawn over the rounded edges of the stretching
collar.
14. A device according to claim 2, the inner frame being inserted
in the outer frame, and a liquid crystal film being held in the
frame by being drawn over the rounded edges of the stretching
collar.
15. A device according to claim 7, the inner frame being inserted
in the outer frame, and a liquid crystal film being held in the
frame by being drawn over the rounded edges of the stretching
collar.
16. A device according to claim 8, the inner frame being inserted
in the outer frame, and a liquid crystal film being held in the
frame by being drawn over the rounded edges of the stretching
collar.
Description
This invention relates to a device for the foldfree stretching and
holding of liquid crystal films.
Liquid crystal films intended to be used for thermographic
diagnosis of cutaneous or sub-cutaneous disorders, for example
breast cancer tumours, have to be stretched without any folds. At
the same time, they must not be overstretched. The most common
method of stretching and fixing very thin liquid crystal films is
to insert the films into smooth frames and bond them in position.
This method is time-consuming and, once the film has been inserted,
any errors in its positioning cannot be corrected.
The object of the invention is to provide a frame in which a liquid
crystal film can be automatically stretched free from any folds
without at the same time being destroyed, the film being fixed in
position once it has been stretched across the frame.
According to the invention there is provided a device for the
fold-free stretching and holding of liquid crystal films,
consisting of a substantially rectangular outer frame having an
.[.external.]. .Iadd.inner .Iaddend.centering edge for an
insertable inner frame comprising an .[.inner.]. .Iadd.external
.Iaddend.centering edge, wherein the inner boundary of the
.[.inner.]. .Iadd.outer .Iaddend.frame is in the form of a
stretching collar, the surface of the collar facing the .Iadd.inner
.Iaddend.centering edge being bevelled, the lower edge of the
stretching collar being rounded off and its surfaces being smooth,
whilst the surface of the stretching collar facing away from the
.Iadd.inner .Iaddend.centering edge is also bevelled, but at a
steeper angle than that surface facing the .Iadd.inner
.Iaddend.centering edge, the corners of the inner boundary of the
outer and inner frames being rounded off, and wherein the outer
.Iadd.inner .Iaddend. frame comprises a stretching groove which
cooperates with the stretching collar and the surface of the
.[.outer.]. .Iadd.inner .Iaddend.frame directed towards the inner
.Iadd.centering .Iaddend.edge of the .[.inner.]. frame is bevelled
parallel to the bevel of the stretching collar.
The particular advantage of the device according to the invention
is that a liquid crystal film may be placed loosely over the frame
in its open position, after which the frame can be closed. The
liquid crystal film is carefully stretched by being drawn over the
rounded edges of the stretching collar. By virtue of the fact that
the surfaces are smooth (through the polished surfaces of the
injection mould), the liquid crystal film slides over the surface
of the stretching collar during stretching without being damaged.
The corners of the inner boundary of the outer frame and inner
frame are rounded off in such a way that the liquid crystal film
cannot develop any fold in this zone either. After stretching, the
film is kept in its stretched position by the frame.
In a preferred embodiment of the device according to the invention,
clips are arranged on the outer frame which are designed to engage
in corresponding openings formed in the inner frame. By virtue of
this measure, the inner and outer frame are held together and the
liquid crystal film is fixed in its stretched position. The outer
and inner frames can only be taken apart using special tools. This
measure precludes unauthorized removal of the liquid crystal
film.
In another embodiment of the device according to the invention, a
double adhesive tape is arranged on the inside of the outer frame.
This is another safeguard against removal of the liquid crystal
film from the frame.
One exemplary embodiment of the device according to the invention
is described in more detail in the following with reference to the
accompanying drawings, wherein:
FIG. 1 shows the two frame parts assembled to each other viewed
from the under side.
FIG. 2 shows the lower .[.outer.]. .Iadd.inner .Iaddend.frame part
in more detail and again viewed from the under side.
FIG. 3 shows a cross section through the .[.outer.]. .Iadd.inner
.Iaddend.frame part along line C--D in FIG. 2.
FIG. 4 shows the upper .[.inner.]. .Iadd.outer .Iaddend.frame part
from the under side.
FIG. 5 represents a cross sectional view along A--B.
FIG. 6 is a cross section along C--D in FIG. 4.
FIG. 7 shows a cross sectional view when the two frame parts are
assembled.
The frame device according to FIG. 1 comprises two registering
parts, the .[.outer.]. .Iadd.inner .Iaddend.frame 1 and the
.[.inner.]. .Iadd.outer .Iaddend.frame part 2. The .[.outer.].
.Iadd.inner .Iaddend.part 1 fits snugly in the .[.inner.].
.Iadd.outer .Iaddend.part 2. When pressed against each other the
clips 3 projecting from the .[.inner.]. .Iadd.outer .Iaddend.frame
2 snap into corresponding apertures 3a in the .[.outer.].
.Iadd.inner .Iaddend.frame 1 so that the two frame parts are firmly
fixed to each other. The screen area 12 is defined (circumscribed)
by the inner rim .[.5.]. .Iadd.14 .Iaddend.of .[.outer and.]. inner
frame .[.parts.]. .Iadd.1. .Iaddend.The corners 9 of the inside
rims of the outer and inner frame parts are rounded off at a radius
of 20-25 mm.
Referring to FIG. 6, the .[.inner.]. .Iadd.outer .Iaddend.frame
part 2 is provided at its inner edge with a particularly formed
bead or stretching collar 4. Stretching collar 4 is defined by
three faces: Face 8 having a steep slope seen from a direction
perpendicular to the screen plane, followed by a rounded lower part
or curved face 7 which changes over again into an ascending plane
face (with respect to the screen plane 12). The face 6 has a
moderate slope compared with face 8. This particular contour of the
peripheral bead or stretching collar is important for stretching
the foil. The angle between the face 8 and the surface normal of
the screen plane 12 is about 5.degree.. The ascending face 6
includes with the surface normal an angle of about 45.degree.. The
radius of the curved face 7 is about 1.2 mm. The bevelled face 6 is
turned to the inner centering edge 5 whereas face 8 is turned away
from edge 5 and faces to the screen plane. The inner centering edge
or rim 5 is provided by the part of the .[.inner.]. .Iadd.outer
.Iaddend.frame 2 which is bent 90.degree. from the screen
plane.
The profile of the .[.outer.]. .Iadd.inner .Iaddend.frame 1 is
adapted to the profile of the .[.inner.]. .Iadd.outer
.Iaddend.frame 2. The registering relationship is shown in FIG. 7.
Note in particular that the external centering edge 13 of
.[.outer.]. .Iadd.inner .Iaddend.frame 1 is contiguous to the inner
centering edge 5 of the .[.inner.]. .Iadd.outer .Iaddend.frame 2,
and the peripheral stretching groove 11 cooperates with stretching
collar 4 of the .[.inner.]. .Iadd.outer .Iaddend.frame 2, when both
parts are assembled, shown in FIG. 7. The inner rim of the
.[.outer.]. .Iadd.inner .Iaddend.frame part 1 is rounded of as
shown at 14.
Referring to FIG. 2, the ribs 15 in the lower frame part are only
serving for reinforcement. Openings 15a are provided for mounting
of the assembled frames on holder for study of the liquid crystal
films. Both frame parts are made for instance from polystyrene by
injection molding technique.
A foil coated with liquid crystals is assembled within the two
frame members in the following manner: The foil is first loosely
put onto the .[.outer.]. .Iadd.inner .Iaddend.frame member 1, the
foil being cut to a rectangular format in such a manner that the
foil projects over the inner rim 14 of .[.outer.]. .Iadd.inner
.Iaddend. frame 1 and ends within face 16 (see FIG. 3) between the
openings 3a for the .[.cramps.]. .Iadd.clips .Iaddend.3 and the
external centering edge 13. Then the .[.inner.]. .Iadd.outer
.Iaddend.frame member 2 is fitted to the .[.outer.]. .Iadd.inner
.Iaddend.frame member 1 and both parts are pressed together so that
the clips 3 are snapped into the openings 3a in the .[.outer.].
.Iadd.inner .Iaddend.frame 1. When pressing both frame members
together, the clips are protruding through the foil. In this
assembling step the foil is slightly pulled over the inner rounded
rim 14 of .[.outer.]. .Iadd.inner .Iaddend.frame 1 and the contour
faces of the stretching collar 4. By pressing the foil into the
stretching groove 11 of the .[.outer.]. .Iadd.inner .Iaddend.frame
part in the assembling step, the foil is moderately stretched in
the screen plane. Surprisingly, it has been found that creases and
warping can be strictly avoided in this way. This is a necessary
requirement for obtaining a high image quality when using a liquid
crystal foil for medical diagnostic purposes. On the other hand the
stretching effect must not be too much in order to prevent the foil
from tearing. Further to prevent tearing the contour faces 6, 7, 8
(FIG. 7) of the stretching collar 4 should be very smooth. This is
easily achieved by polished surfaces in the injection molding form.
Regarding the delicate problem of achieving an absolutely smooth
foil surface in the screen plane, the frame members according to
the invention constitute a unique solution for this particular
object.
A further improvement for securing the foil may be achieved by
providing adjacent faces in the region beneath clip 3, for instance
face 16 (FIG. 3) with double sided adhesive tape 17 (FIG. 7) so
that the marginal zone of the foil sticks to either one of the
frame parts 1 and 2.
Normally the clips 3 provide for a reliable connection between the
two frame members. With higher requirements the two frame members
may also be welded to each other.
* * * * *