Note: Descriptions are shown in the official language in which they were submitted.
FIELD OF THE INVENTION
This invention relates generally to the
examination of fluid specimens and more particularly to
an improved transparent slide for receiving ana retaining
a thin film of a specimen before and during optical
examination.
, ~
cr/,,~
-- 1 --
BACKGRO~ND OF THE INVE~TION
A common means of preparing liquid specimens for micrOscoQic
examination has been to place a small quantity of the ~luid on a
flat, transparent slide plate and then placing a thin flat
transparent cover slip over the specimen. The cover slip press2s
against the plate and spreads the fluid into a thin film in the
; space between the two elements. Thereafter, the liquid is
retained in the space between the two elements by capillary
action, that is, by the attraction of the liquid molecules for
each other and for those of the solid materials forming the slide
and cover slip. It Is the space formed between the two elements
in which sample specimens are retained that is hereinafter
referred to as the capillary chamber. The thus prepared slide
with the specimen is then placed on a microscope stage and is
microscopically examined through the transparent cover slip.
; One purpose for which a specimen so prepared is examined is
to permit quantitative microscopic analysis of particulate matter
in the fluid. Fluids which are typically examined by such
procedures include urine, blood, spinal fluid, sputum and cell
cultures. When the specimen has been spread to a film of
generally uniform thickness, the technician is able to count the
number of solid particulars, cells and the like in a given area
of the specimen and this count is indicative of the content of
the specimen per unit volume thereof. Tne actual volume of fluid
confined beneath a given area of the cover slip is dependent upon
several variables, among them being the size of the drop of
liquid applied to the slide plate, the viscosity of the fluid,
the force applied in squeezing tne cover slip against the plate
and the ~latness of the two elements in their confronting
relationship. The distribution of solid particles in the
specimen, particularly larger particles, can be affected by tne
squeezing action, and slippage can occur between the cover slip
and the plater thereby possibly adversely affecting the accuracy
of the examination. Because the thickness of sample depends on
the amount of sample placed on the slide, as much as a 50-200
error can be introduced.
Wet mount slides of the type mentioned above have commonly
been made of glass and normally a single specimen can be examined
by one combination of plate and covee slip. Also, a relatively
significant amount of dexterity, manipulation and skill is
necessary to apply the specimen on the plate, place the cover
slip thereon and handle the prepared slide until examination is
completed. If an excess amount of the specimen is placed on the
plate, it may be forced out of the space between the plate and
the cover slip when they are positioned together. Removing the
excess specimen without physically disturbing the position of two
elements requires some skill. Furthermore, the entrapment of air
between the plate and the cover slip can form undesirable bubbles
which interfere with the accuracy of the examination. Another
limitation oE conventional wet mount slides has been the general
impracticality of applying more than one SQecimen per slide. The
contamination due to the intermixing of specimens is unavoidable
where the spreading of the samples beneath the cover slip is
uncontrolled. The cover slip also serves to protect the specimen
from contamination by the technician, the objective of the
microscope, and the enviro~ment.
Tne results of any analysis done by a technician are
necessarily dependent on the skill and experience of that
technicianO For consistency, uniformity, and reproducability of
results, it is important that sample sizes for a particular fluid
be controlled both by the amount of specimen analyzed, and the
depth of tne capillary chamber for optimum accuracy.
Efforts have been made to provide unitary liquid specimen
holders which overcome the disadvantages of the two-part slide
mentioned above. Two of such examples of prior art are the U.S.
Patents issued to White, ~o. 3,961,346 and Elkins, No. 3,777,283
(referred to as the '346 White patent and the '283 Elkins patent,
respectively). Both attempts have been less than completely
satisfactory in dealing with the problems previously discussed.
In the device of the '346 White patent, the two surfaces forming
the capillary chamber are not parallel thereby resulting in a
variation in the density of the particulate matter, depending
upon the lateral position within the chamber. To deal with tne
problem of air bubble entrapment in the capillary chambers, the
devices of the '346 White patent and '283 Elkins patent both make
use of s~oothly curved side walls to prevent any sharp corners
where bubbles might collect. However, because both systems are
closed systems, when the specimen is introduced into the chamber,
undesirable air bubbles aee often formed which are difficult to
remove.
~ .
- ~.2~
The devices in both the '346 White patent and '283 Elkins
patent are one piece molded plastic devices with no possibility
of adjustment of the thickness of the capillary chamber, that is,
the spacing between the plate and cover slip. The capillary
chambers of such slides can convenien~ly be molded with a spacing
of 0.005 inch (0.127mmj to about 0.~15 inch (0.381 mm), and it -
has not been practical to directly mold a slide having smaller
spacing, even though a thinner specimen chamber could at times be
desirable.
The removal of excess sample remains a problem with both the
inventions of the '346 White patent and '283 Elkins patent since
both require manual manipulation and/or towelling oEf of the
excess by the techniclan. ;
The U.S. Patent No. 2,039,219 to Hausser discloses a wet
mount examination slide wherein the slide plate, formed in a base
member, is surrounded by overflow channels. The Hausser cover
slip, however, has no positive interconnection means to the base
member and, consequently, the relative and exact positioning of
cover slip to plate surface is difficult to maintain while
charging the examination chamber.
The present invention allows excess sample to flow freely out
of the capillary chamber and into a trough on the slide while
avoiding the problems inherent in Hausser.
SUMMARY OF THE INVENTION
Broadly speaking, this invention relates to a transparent
laboratory slide which may be described as an open system wherein
the capillary specimen chamber is open on all sides and wherein
the two surfaces of the chamber are parallel, thereby
faci1itating an accurate count of the substance of interest in
the fluid being examined.
The invention provides a multiple universal transparent slide
apparatus formed with parallel plate and cover slip surfaces
which may be precisely spaced by varying distances as desired to
accommodate fluids of different viscosity, while obviating the
bubble formation problem o known slides.
A base element is formed with a plurality of platforms having
flat surfaces which perform the function of the slide plate of
the previous two piece slide and cover slip combination. A
V-shaped groove sloping away from the outward facing platform
surface provides for introduction of the specimen fluid into the
chamber, one side of which is the platform surface. A multiple
element cover slip is adapted to removably attach to the base
member and provide precise spacing as desired between the
un~erside oE each cover slip element and the corresponding
platform surface. An open space is provided between parts of the
cover slip and sides of the platorm which raise the platform
surface above the bottom wall of the base element so that each
: , .
~oe
transparent slide is an open system wherein it is very
unlikely that bubbles can form in the capillary chamber
when the specimen is introduced into it. The releasable
attaching means between the base and cover slip elements
are preferably male and female peg and socket elements
which fit toge-ther in such a way that with slight height or
thickness changes in one of the elements, the chamber
: spacing may be made larger or smaller as desired for the
particular fluid being examined.
: 10 In summary of the above, therefore, the present
invention may be considered as providing a dual member
transparent laboratory slide consisting of: a base member
having a bottom wall with an upper surface, the base m2mber
being integrally formed with at least one plate surface
spaced above the upper surface, a fluid receiving surface
communicating with the plate surface, and a first
interconnecting means; a cover member formed with at least
` one cover slip having a lower surface adapted to be located
in spaced confronting parallel relationship with respect to
the plate surface, the cover member being integrally formed
with second interconnecting means complementary with the
first interconnecting means, the first and second
interconnecting means being adapted to removably attach the
cover member to the base member; and the first and second
Y interconnecting means being adapted to be shaped and
configured to selectively provide a predetermined spacing
between the plate surface and the cover slip to thereby
-- 7 --
lcm/~
A
..
form a capillary chamber therebetween of selecta-
predetermined spacing, and also providing substanti2
rigid positioning of the cover slip and plate sur~--
against lateral movement, the capillary chamber being G-
on all sides and wherein the cover slip covers onl
portion of the fluid receiving surface where
communicates with the platP surface.
The present invention may be distinguished --
the closest prior art since it obviates the problem of
bubble entrapment since all four sides of the base ele -
platforms are open to allow the escape of any air
capillary chambers of this invention are uniqr-
characterized by this lack of side walls. Also, the ra
platforms of the base element create troughs between
platorms where excess sample is free to overflow~
upper and lower surfaces of the capillary chambers
parallel to each other providing a uniform densit~
!
accura~e inspection.
~ .
~- BRI~F D~SCRIPTION OF THE DRAWI~GS
The objects, advantages and features of ts
invention will be more readily apparent from the follc-
detailed description when read in con~unction with
accompanying drawing, in which:
- 7a -
lcm/,!
,
394
FIGURE 1 is an exploded view of one embodiment of the base
and cover slip members of the transparent slide of the present
invention;
~ IGURE 2 is a top view of the slide of FIGURE 1 with a
portion of the cover slip broken away;
FIGURE 3 is a bottom vie-~ of the cover slip of FIGURE l;
FIGURE 4 is an enlarged sectional view taken along line 4-4
of FIGURE 2;
:,.. .
FIGURE 5 is a plan view of a second embodiment of the base
and cover slip members joined by a hinge means;
' ,
: FIGURE 6 is an end elevational view of the embodiment of
FIGURE 5;
'
FIGURE 7 is a perspective view of a third embodiment of the
base and cover slip members, in assembly, comprising the
transparent slide of ~he present invention;
FIGURE 8 is an exploded view of the third embodiment of
transparent slide shown in FIGURE 7; and
FIGURES 9 to 11 are cross-sectional views of the assembled
transparent slide, taken along the lines 9 - 9, 10 - 10 and 11 -
11 of FIGURE 7, respectively.
DESCRIPTION OF THE PREFERRED EMBOûIME~TS
With reference now to the drawing, FIGURE 1 shows cover
member 11 in position above base member 12 for removable
engagement therewith. The cover member 11 is formed with a
plurality of cover slips 13 which are very thin, in the ordee Oe
0.004 inch (0.1 mm) to 0.0099 inch (0.25 mm). As shown in the
drawing, cover slips 13 are spaced side by side longitudinally on
the cover member 11, separated by supporting elements 14 which
are substantially .thicker than the cover slips and spaced from
the lower surface of the cover slips by side walls 17. Cover
slips 1~ are positioned on opposite sides of the c~ver 11,
separated b~ ribs 15 which are relatively narrow but typically of
the same thickness as supporting elements 14. Pegs 16 extend
downwardly from the supporting elements and provide part of the
means for interconnecting the cover 11 with the base member 12.
Base member 12 is formed with a bottom wall 21 having an
upper surface 22 and socket elements 23 projecting upwardly from
surface 22. Sockets 23 are formed with holes 24 therein which
are adapted to receive pegs 16 with supporting elements 14
resting on the top bearing surfaces 25 of the socket elements.
The outside dimensions of bottom wall 21 are defined by edge 26
which completely surrounds the bottom wall and functions as a
stiffening element for the base member 12. The base member 12 is
also formed with a plurality of platform surfaces or slide plates
27 spaced above upper surface 22 of the bottom wall by means of
vertical walls 31, 32 and 33. Communicating with plate 27 is
fluid receiving surEace 34 which is triangularly shaped and
slopes away from the plate as is shown clearly in FIG~ES 1 and
4. Each 1uid receiving surface 34 is defined by walls 35 and 36
whic'n, together with Eluid receiving surface 34 further defines
the ~luid receiviny groove or passage 37. It should be noted
that the inner ends of walls 35 and 36 do not meet because the
surfaces 27 and 34 are continuous through narrow passage 37
(FIGURE 2).
When the laboeatory slide o this invention is to be used,
cover element 11 is mounted to base 12, pegs 16 Erictionally
engaging holes 24 in socke~ elements 23 with sUpporting surfaces
14 resting upon rim 25 of the sockets. In this position, the
bottom of cover slips 13 are spaced above plates 27 by a
predetermined distance. That spacing is preferably in the range
of 0.001 inch ~0.0~54 mm) and 0.00~ inch ~0.1 rnm), but the
structure is not so limited. This spacing constitutes a
capillary specimen chamber wherein ~luid to be examined is
retained be~ween the cover slip and the platform surface by
capillary action of that fluid. Thus the spacing may be that
which is appropriate ~or any particular fluid. The base and
cover slip members are so constructed that the distance 41
(FIGURE ~) between adjacent plates is greater than the width of
supporting elements 14 of tne cover member and the s~acing 42
between opposite plates is greater than the width oE ribs 15.
With this construction, it is readily apparent that the
laboratory slide of this invention is an open system whereby all
sides of the plate communicate with the external environment and
there is no possibility of air being trapped within the capillary
chamber when fluid is introduced tnerein.
As has been alluded to above, because fluids to be
microscopically examined differ significantly in their viscosity,
it is often desirable to employ laboratory slides where the
capillary c~ambers are not all of the same spacing. By means Oe
the pcesent structure, it is possible to provide slides which are
suited to specific ~luids without any change in the principles of
the invention. One means Eor providing a different capillary
chamber spacing is to increase or decrease the height of socket
elements 23. From FIGURE 4 it is apparent that an increase in
height of the socket element 23, without any change in the cover
membe~ 11, will increase the s~acing between cover slip 13 and
plate 27 to accommodate a fluid of greater viscosity.
Conversely, shortened socket element 23 will narrow the capillary
chamber for lower viscosity fl~ids. Alternately, the thickness
of support surface 14 can be increased or decreased with the same
effect. It should be noted that only one of the two members, the
base member or the cover me~ber, need to be formed with elements
of different si2es to change the capillary chamber thickness.
The other member can be standard for all examination purposes.
Another means by which to provide different capillary chamber
11
spacing is to ma~e holes 24 blind and varying the length of pegs
16. In that event, making the pegs longer would increase the
chamber spacing and supporting elements 14 would not necessarily
rest upon the tops of sockets 23.
One simple interconnecting means, a peg and socket
combination, are shown and described. However, there are m~ny
other interconnecting means which could be used to provide the
desired releasable retention between the two mem~ees, togetner
with flexibility as to the capillary chamber spacing.
In accordance with known microscopic examination techniques,
the laboratory slide o~ this invention provides both low powèr
with a magnification factor of about 10 and high power with a
magnificatlon of 45 to 55. It is also possible to employ the
slide o~ this invention for oil immersion whereby the
magnification factor can be increased to 100. As is well known,
the cover slip protects the objective of the microscope from
becoming contaminate~ by contact with ~he fluid being examined.
In the same way that it provides protection for the ~icroscope
and the fluid, it can support a drop of oil into which the
objective can be placed for increased magnification without
contaminating either the objective or the fluid under
examination. Because of the fact that the cover slip of this
laboratory slide can be made very thin, its optical
characteristics are excellent and generally better than those of
the one piece molded slides previously available.
~ 7hen the laboratory slide of this invention is to be used for
examination of fluids, and the base member and cover elements
12
~,
have been secured together, it may be seen that the outer edge 42
o the cover slip extends slightly over the narrow portion of
fluid receiving surEace 34 where it communicates through passage
37 with plate surface 27. It should be noted that the fluid
receiving surfac~ may have various shapes but preferably is
triangular so that its innermost apex 34a serves as a locator for
,a pipette,,en,d,;,,the,f,l~uid receiving surface 34 communicates with
plate 27 and is configured as to facilitate fluid migration into
the specimen chamber by capillary action. With reference to
FIGURE 2, ~he slide should be tilted to a somewhat vertical'~ -
position so ,that f,luid receiving areas on one side open upward.
A drop of fluid placed in one fluid receiving area will migrate
by capillary action into the capillary chamber beneath cover slip
13 and on top of plate surface 27 and the air which is normally
between these two surfaces can escape in any direction from
between them.
Several different,specimens may be placed in the laboratory
slide, one specimen in each of the numbered areas so that several
may be examined on one laboratory slide. Upon completion of the
examination of the fluids in the specimen chambers, the slide may
be disposed of. ~or indexing purposes the numerals may be
provided on the unde,r side of fluid receiving surface 34, but
that convenience is not necessary. Although users normally find
the multiple slide arrangement to be desirable, it i~s possible
that some people would want a single or possibly a dual slide
1,3
configuration. This invention is not limited to any particular
number of slides.
It should be noted that the capillary chamber can be made
with any desired spacing between the plate and the cover slip and
is not limited by the molding process as is true oE some of the
prior art devices. By fabricating the plate and cover sllp
separately, the spacing of the capillary chamber can be made
significantly thinner than those of prior art, thus allowing a
single layer of specimen to be viewed. This structure enhances
the accuracy of examinations made. When the fluid is placed in a
chamber, excess fluid can be conveniently removed by tilting the
slide and allowing such excess to fall off. The liquid in the
capillary chamber will be retained therein by capillary a~tion~
The material of both elements of the slide of this invention
is preferably plasticr being optically transparent, having the
desired degree of wettability and can be conveniently injection
molded. Examples of plastics which are satisfactory for this
purpose include cellulose ester compositions such as cellulose
acetate and cellulose acetate butyrate. A number of other
plas~ics could also be satisfactory.
Referring now to FI~URES 5 and 6, the base 120 and cover
members 110 could be molded as a single integral piece with a
plastic hinge 140 between them. In this way, the elements would
never become separated from one another and the cover element 110
could easily be folded over onto the base member 120 so that the
pegs 150 engage the socket elements 145.
14
3~
Although hinges o~ simple strips of plastic could be affixed
along either the long or short sides of the slide and cover slip,
for accuracy of fabr1cation, it is presently preferred to place
the hinges 140 alon~ the long edges in order to reduce tooling
costs.
The embodiment of FIGURES 5 and 6 is particularly useful in
an application of the present invention wherein specimens are
placed on the ~late surface 127 and the hinged cover slip 110 is
attached. This application is of particular usefulness in
instances such as those that arise in the field of bacteriology
(i.e. in testing for gonorrhea) where a series of stains must be
applied to a specimen before microscopic viewing.
Grid marks or lines to indicate different examination fields
might be incorporated in the fabrication of the cover or base
member. A portion of the slide might be formed of frosted
plastic for application of indicia for identification purposes.
~ n the third embodiment of this invention, shown in FIGURES 7
- 11, the examination areas defined by the plurality of plate
surfaces and confronting cover slips, are each substantially
coextensive with the width W of the transparent slide~ That is
to say, each examination area is over twice as large, in area, as
the first and second embodiments heretofore described in FIGURFS
1 - 6 ~- even though the overall width of the transparent slide
in the third embodiment of FIGURES 7 - 11 is the same as that of
the FIGURES 1 - 6 embodiments. The enlarged examination area is
especially suitable in the examination of specimens requiring
-
.
larger examination areas such as parasites in stool samples and
monoclonal antibodies in blood plasma.
~ lore particularly, the slide of the FIGURES 7 - 11 embodiment
is designated generally by the numeral 200. The cover member is
designated by the numeral 202 and the base member as 204.
The covee member is formed with a plurality of cover slips
208, each having a lower surface 209 located ln spaced
confronting relationship to a plurality of plate surfaces 210 in
the base member 204 when the cover and base members 202, 204 are
assembled by respective first and second complementary post (or
peg) and socket interconnecting means 212, 214.
The post and socket interconnecting means 212, 214 removably
interconnect, or attach, the cover and base mebmers 202, 204. In
the interconnected position (i.e., the fully assembled position
shown in FIGURES 7 and 9 - 11), the cover slips 209 are spaced a
predetermined distance 215 from the plate surfaces 210, the
~pacing 215 between plate surface 209 and cover slip 210
tpreferably about O. 0254 mm to 0.1 mm) being reproducibly
achieved by means of predetermining the dimensions of the
thic~ness of supporti~g surfaces 2i6 which separate cover slips
208, and/or the height of sockets 214. Thus, when the supporting
surfaces 216 lie in abutment with the top rim 223 of the sockets
214 (the pegs or posts 212 frictionally engaging the holes 219 of
the sockets 214, as described with reference to the FIGURE 1 - 5
embodiment), the spacing 215 is predetermined to very close
tolerances. When either of the socket height or thickness of
supporting surface 216 is changed, spacing 215 will be varied.
16
Each plate surface 209 has a fluid receiving surface 222
shaped in the same menner as described with reference to FIGURE 1
- 5. The supporting surEaces 216 are formed on opposite sides of
cover slips 208 and extend below the cover slip lower surface 209
tsee FIGURE 11).
The covee member 202 does not have a rib element as in FIGURE
1 - 5 since the cover slips 209 extend entirely from side to side
of the cover member 202 and together with plate surfaces 210
(which also extend entirely from side to side of base member
204 -- except for fluid receiving area 222) define an examination
area over twice the size of the examination area of the FIGURE 1
- S embodiment.
It is to be noted that in the thir? embodiment of this
invention, the examination chamber is open along all sides, as in
the FIGURE 1 - 5 embodiment, so that excess fluid deposited in an
examination chamber may overflow into side channels 224. This
third embodiment is thus an open system as with the FIGURE 1 - 5
embodiment~ In the FIGURE 1 - 5 embodiment, however, the
overflow fluid can be deposited no~ only into side channels, but
into an end channel, defined by vertical walls 33, as well.
,
