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TECHNICAL AREA
This invention relates broadly to equipment and methodologies which are
based upon or which utilize light as an energy form to obtain
condition-indicative response data for evaluation or analysis purposes.
Somewhat more particularly, the invention relates to calibration methods
and apparatus for use in or with optical response methods and apparatus in
tissue examination and analysis; in particular, human tissue, examined in
situ and in vivo. More particularly still, the invention relates to
methods and apparatus for calibrating the performance of optical probes
utilized in such examination procedures, which are generally of a type
having light-sending portions and light-receiving portions which cooperate
together to inject light energy of a selected character into a selected
tissue area and to detect or collect the light energy emerging from one or
more selected positions on the tissue specimen or body.
BACKGROUND OF THE INVENTION
The utilization of light energy and the principles of physics involved
therewith for purposes of examination and analysis of living tissue, in
particular human tissue, is rapidly becoming recognized as a highly
promising and useful methodology. One particularly advantageous such
modality is described in my earlier, co-pending application Ser. No.
542,022, now U.S. Pat. No. 4,570,638, in which preferred embodiments and
concepts are disclosed for carrying out such optical (i.e., light-physics)
procedures, in the in vivo examination of human anatomy, in particular
diagnostic breast examination. Reference is made to such co-pending
application for a more complete discussion and disclosure of the apparatus
and methodologies involved (such application being incorporated herein by
reference).
One aspect or attribute of the methods and apparatus disclosed in the
above-mentioned co-pending application comprises a manually-operated
optical instrument by which light-response data is obtained from the
living human tissue being examined. That instrument, which may be referred
to as a "probe" (although not in a limiting sense), comprises basically a
pair (or more) of probe terminals or active operating portions which are
movable relative to one another for use in examination procedures by
placing the selected portion of the body between the two such terminal or
operative portions and bringing the latter close enough together to gently
bear against opposite sides of the examination area. At least one of the
terminal portions has a light-emitting member or element, for example, the
end of a fiber optic bundle or cable, and at least one other such probe
terminal includes at least one light-receiving sensor, detector, or other
"receptor". In general, the instrument operates by pulsing light energy
from the emitting element and detecting such energy, after dispersion,
"scatter", and other such effects within the tissue under examination, at
the sensor or collector located in the other part of the probe. While it
will be understood that the actual nature of the two (or more) probe
terminal portions is considerably more comprehensive than the apparatus
just described, including for example, other light-sensors or collectors
located at other positions as well as other possible light sources and/or
positions, the basic nature of the apparatus is generally as just
described.
In the use of such optical response instrumentation, it is inherently of
the greatest importance that the response data which it produces be and
remain consistent and comparable, and remain so throughout the useful life
of the instrument in generating data for evaluation. That is, the sending
and receiving characteristics of the light source and light receptors used
in any two given different instruments may and probably will be at least
somewhat different, and will probably change with time and usage as well.
The same is true with respect to the electronic components generally, used
in the data-conditioning and processing circuits, etc. Thus, if reliable
data is to be obtained, and if that data is to be meaningfully compared
with other data taken at different points in time and/or by different
instruments, it is essential to provide a way in which correlation may be
assured for all such data, e.g., a way in which calibration of the sending
and receiving characteristics of all such instruments may be reliably
determined and maintained.
SUMMARY OF THE INVENTION
The present invention provides methods and apparatus for achieving the
above-described calibration of the light-emitting or light-injecting
portions of optical probe terminals with respect to the light-collecting
receptor portions of such probe terminals, for optical instrumentation of
the general type discussed above.
In a first sense, the present invention provides calibration or test
apparatus for insertion between two opposing optical terminals of the same
test instrument, with the two such terminals being moved toward one
another and seated in the opposite ends of the calibration apparatus.
The invention also provides calibration or correlation methodology by which
a sequence of light-emission and light-reception steps are conducted after
the aforementioned apparatus has been so positioned, by which the results
obtained are in effect compared to previously-determined standards, and
variations are rapidly perceived and compensated or corrected.
In a somewhat more particular sense, the apparatus provided by the
invention comprises wideband attenuation and diffusion means, including a
succession of sequentiallydisposed diffusion chambers interconnected by
particularlydisposed apertures for passage of proportioned amounts of
light energy along a labyrinthine path extending between the two probe
terminals.
In a further sense, the apparatus of the invention includes a calibration
device generally of the aforementioned character but having one or more
sample cells disposed within the device and along the optical path
therewithin, by which selected tissue samples may be examined by the
selectively dispersed and attenuated light passed through the device,
and/or such light may be subjected to one or more known media constituting
test standards.
Further still, the calibration device preferably has means for removably
receiving a standard type of sample cell, whereby different such cells may
be used at different times in the same calibration device, one cell being
removed and another being substituted for it, with the calibration device
itself remaining in place at all times for testing.
In a physical sense, the calibration apparatus in accordance herewith is
preferably structured in the form of a modular device, with removable and
interchangeable components, for additionally facilitating flexibility in
calibration procedures.
In addition to the above, the invention provides novel methodology for
calibration optical test apparatus and correlating optical test
information (data) obtained by use of such apparatus, pursuant to which
the data obtained from any and all test instruments used at any and all
times is made to be directly compatible and comparable, for accurate and
meaningful interpretation and for obtaining meaningful data bases and
compilations, and for analysis, greatly agumenting the usefulness of all
such data and extending the knowledge obtainable therefrom.
The foregoing major attributes of the present invention will be seen more
comprehensively, and in more detail, by consideration of the ensuing
specification and the appended drawings, setting forth particular
preferred embodiments of the underlying invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the appended drawings:
FIG. 1 is a side elevational view of an exemplary optical probe or
instrument in connection with which the invention is described;
FIG. 2 is an end elevation of part of the structure shown in FIG. 1, as
seen from along the plane II--II thereof and viewed in the direction of
the arrows;
FIG. 3 is an end elevation of another part of the structure shown in FIG.
1, as seen from along the plane III--III thereof and viewed in the
direction of the arrows;
FIG. 4 is an enlarged, sectional side-elevational view of a first form of
calibration instrument provided herewith;
FIG. 5 is a fragmentary sectional elevational view taken along the plane
V--V of FIG. 4.
FIG. 6 is a sectional side-elevational view of a second form of calibration
instrument in accordance with the invention, taken generally along the
compound plane VI--VI of FIG. 4;
FIG. 7 is an overhead plan view of the apparatus shown in FIG. 6;
FIG. 8 is a sectional plan view taken along the compound plane VIII--VIII
of FIG. 6; and
FIG. 9 is a sectional plan view taken along the plane IX--IX of FIG. 6.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to FIG. 1, the optical response instrument depicted there
for purposes of illustration comprises basically a pair of cooperative
component members 12 and 14 (which may be referred to variously as "probe
terminals", "component heads", etc.) which are mounted upon an
interconnecting guide member 16, along which at least one of the heads or
terminal members is slidably adjustable while remaining at all times in a
consistent orientation with respect to the other such component or head.
The guide or support 16 may incorporate length-measurement indicia or
read-out means, so that the relative distance between the two component
members 12 and 14 may readily be determined at any given position of
adjustment since, as disclosed in the aforementioned co-pending
application, the particular separation distance between the two component
members 12 and 14 is very important in each different test or examination
situation as an indication of optical path length, and this distance will
of course vary from one patient or subject to another. Each of the two
component members 12 and 14 is coupled by respective cables 18 and 20 back
to a source (not shown) of required optical and/or electrical energy, as
well as to various information-storage and processing means, all as
disclosed in the aforementioned co-pending application. As there
disclosed, the two connecting cables 18 and 20 may include either or both
optical and electrical conductors, e.g., fiber optic bundles and/or
current-carrying wires.
More particularly, each of the component members 12 and 14 include
light-emitting and/or light-detecting elements which, depending upon the
particular details of the preferred embodiment involved, may constitute
electrically-operated elements or optical components, e.g., fiber-optic
bundles. That is, the actual light energy to be injected may be conducted
to the component head through a fiber-optic bundle and injected into the
tissue under examination from the end of the fiber-optic bundle itself;
conversely, light detection may be accomplished by use of an
electrically-responsive light detector (e.g., a silicon photo-voltaic
cell, silicon photo-diode, lead-sulfide cell, etc.) The point is, such a
detector may be located either at the optical probe heads or terminals or
at the opposite end of their connecting cables, within an equipment
console, cabinet or the like. In the latter event, the component heads or
members 12 and 14 will nonetheless emit and detect light energy, but will
include only fiber-optic cable ends, as opposed to electrically-operated
detectors such as photodiodes and the like.
Examples of typical structural configurations and relationships for the
probe terminals or component members, 12 and 14 are shown in FIGS. 1, 2,
and 3. Referring particularly to these figures, probe terminal 12 is
depicted as including a source of light energy, in this example the end of
a fiber-optic bundle 22, as well as light detection means, in the
illustrated example comprising a pair of photo-voltaic cells 24a and 24b.
Both he fiber-optic bundle 22 and the two photo-voltaic cells are provided
access to the area immediately beyond the probe terminal (e.g., the
specimen or subject from whom data is to be obtained) through an aperture
plate 26 serving to otherwise close the operative end of the probe
terminal. Immediately behind the aperture plate 26, a
perpendicularly-positioned septum 28 extending between the rearward
surface of the aperture and the front surface of a structural wall 30 in
which the photo-voltaic detectors 24a and 24b are mounted serves to
isolate the fiber-optic bundle from the detectors. Both the fiber-optic
bundle 22 and suitable electrical connecting wire 32 from the optical
detectors emerge from the probe terminal 12 and together constitute the
coupling cable 18 noted above.
The probe terminal 14 is, in general, similar to probe terminal 12
described just above, except that in the embodiment illustrated this probe
terminal houses only optical detectors rather than light sources (although
as stated above various such arrangements, provided for purposes not
integrally related to the present invention, may be encountered and are
within the scope of the present invention). In the illustrated embodiment
of probe terminal 14, the four detectors 34a, 34b and 36a, 36b are mounted
in a structural wall or detector deck 38 analogous to the structural wall
30 noted above in connection with probe terminal 12, discussed above, and
like the photo-voltaic cells 24a and 24b are recessed somewhat inwardly of
the end extremity of the probe terminal. As in the case of probe terminal
12, probe terminal 14 also preferably includes a septum 40 which isolates
the two detector sets (i.e., set 34a and 34b, and set 36a and 36b) from
one another. The end extremity of probe terminal 14 may be closed by a
desired aperture plate or filter disc 42, although this is not strictly
necessary where the probe terminal includes only light-detector elements
rather than a mixture of light-emission and light-detection elements.
A first embodiment of a test instrument calibration apparatus in accordance
with the invention is illustrated in FIGS. 4 and 5. As seen there, the
calibration apparatus 50 includes a generally tubular body 52 having a
shape and internal diameter at each opposite end sized to receive the
forward ends of probe terminals 12 and 14. Preferably, the open ends of
the tubular body 52 are annularly relieved, as at 54, to the extent
required to enable insertion of the endmost extremity of the probe
terminals, thus substantially precluding the escape of light from between
the inside of the terminal body and the outside environment, past the
inserted end of the probe terminal. In the embodiment illustrated in FIGS.
4 and 5, and with reference to the probe terminal embodiments discussed
above, the annular relief 54 is sized to receive the forwardmost end
extremity of probe terminal 14, whereas the opposite end 56 of the tubular
body 52 is intended to receive the forwardmost end of probe terminal 12.
More particularly, in the embodiment illustrated in FIG. 5, the end 56 is
deeply recessed, or counterbored, to receive a cup-like insert member 58,
which preferably telescopes into the tubular body 52 sufficiently to
provide the aforementioned recessed are 56, which is to receive the end
extremity of the probe terminal 12. Preferably, the axial extent (depth)
of recess 56 should be on the same order of magnitude as that of recess
54, at the opposite end of the tubular housing. Insert cup 58 should fit
snugly against the recessed side walls of the tubular housing 52, so as to
block the passage of light therebetween.
Extending diametrically across the insert cup 58 is a septum member 60
which divides the cup into a first and second diffusion chamber 62 and 64,
respectively. Beyond the insert cup 58, the remainder of the interior of
tubular body 52 defines a further diffusion chamber 66. Diffusion chamber
62 communicates optically with diffusion chamber 64 through a pair of
spaced apertures 68a and 68b extending through the bottom extremity of the
septum 60. In an analogous manner, diffusion chamber 64 communicates with
chamber 66 through an interconnecting aperture 70; however, in this
instance there is but one aperture 70 and it is located between
(essentially midway) the two septum apertures 68a and 68b. As illustrated,
the septum apertures are preferably located near the bottom of the septum,
i.e., near the innermost end or wall 72 of the insert cup 58, through
which aperture 70 extends. As will be noted, aperture 70 is located close
to, but off, the axial centerline of the tubular body 52, on which the
septum 60 is aligned.
As indicated above, the calibration apparatus 50 may be considered as
comprising a sequence of diffusion chambers communicating with one another
and extending between the light source and the light receivers or
collectors of the optical probe or test instrument. In this respect, the
active ends of the probe terminals 12 and 14 are, as noted above,
effectively sealed from ambient light by their close-fitting insertion
into the opposite ends of the tubular housing 52 and, in the embodiment
under discussion, a seal 72, of soft, black sponge-rubber or the like, is
preferably provided atop the septum 60. As explained more fully below, the
desired arrangement is for the septum 24 in optical probe terminal 12 to
be in coplanar alignment with septum 60 such that one in effect
constitutes an extension of the other, and the light source is effectively
isolated from all parts of the tubular body 52 except for the first
diffusion chamber 62 thereof. It is important to note that all insides
surfaces of the diffusion chambers 62, 64 and 66 should be randomly
textured, as by sandblasting, to produce a highly-diffusion surface;
furthermore, this surface should preferably be flashed (plated or
otherwise covered) with a thin layer of gold, or an optical equivalent,
for minimum absorption and optimum diffusion qualitites.
For the many reasons described and discussed in the above-mentioned and
incorporated co-pending application Ser. No. 542,022, in at least certain
technologies and methodologies which may be carried out by use of optical
test instruments such as that depicted generally by the numeral 10 in the
drawings and discussed above, it is highly desirable to utilize a "near"
light receiver or detector located in or reasonably close to the same
probe terminal as that in which the light source is located. This near
receiver corresponds to the photo-voltaic cells 24a and 24b noted above,
which are thus positioned in alignment with the second diffusion chamber
64 when the correlation chamber 50 and the two probe terminals 12 and 14
are in their desired positions of relative alignment, i.e., with the
septum 24 of probe terminal 12 in coplanar alignment with the septum 60 of
the calibration chamber, in which position the end extremity of the fiber
optic bundle 42 is aligned with the first diffusion chamber 62. Further,
in the desired positioning relationship between probe terminal 14 and end
54 of the calibration chamber, septum 54' should also be aligned in a
coplanar fashion with septum 60 of the correlation apparatus and septum 54
of probe terminal 12. In this relationship, each of the sets of detectors
34a, 34b and 36a, 36b will be aligned with opposite ones of the first and
second diffusion chambers 62 and 64, in which position one such set of
detectors will be in essentially direct alignment with the aperture 70, in
the bottom of chamber 64, which as stated above is nearly axial with
calibration chamber. In order to help insure proper relative positioning,
an appropriate indicator mark on the outside of each of the two probe
terminals and of the tubular body 52 of the calibration device may be
helpful, e.g., embossed or printed arrow markers, pointers, or the like,
which are to be moved into positions of mutual alignment by rotation of
the calibration device into its proper position between the two probe
terminals.
The use of the calibration, or correlation, apparatus 60 is described below
following disclosure of a second (and preferred) embodiment in the
immediately-ensuing paragraphs. It is to be noted here, however, that
although the embodiment of the device 60 is described above as containing
an open air-filled interior, the various "diffusion chambers" are not
necessarily restricted to that media (i.e., air). On the contrary, any of
such chambers may in fact contain other media, for example water, carbon
tetrachloride, fused quartz, etc., depending upon the particular nature of
the calibration/correlation process which is required, as dictated by the
particular use being made of the optical probe instrument. With respect to
such usage of non-air media in the chambers any of the latter may simply
be permanently filled with the desired media and sealed; alternatively,
the chambers may be configured to receive a given type of sample cell
containing the desired media, or specially-shaped sample cells may be made
to fit the confines of chambers such as those shown in the embodiment
illustrated herein. Such cells may be made to be removable and
interchangeable, so that different types of media may be used in
successive, interrelated calibration sequences. Generally, it will be
desired to place such media-filled sample cell in at least the first
chamber 62, so that the injected light encounters (passes through) the
media before encountering other chambers or outlet apertures. Additional
media may also be located in other chambers, however.
FIGS. 6-9, inclusive, illustrate a second and most preferred embodiment of
calibration apparatus in accordance with the invention. In this
embodiment, the overall calibration apparatus is designated generally by
the numeral 100 (FIG. 6) and preferably comprises three different modules
102, 104, and 106, which are made so as to interfit with one another but
are preferably secured together in a manner permitting separation from one
another, as by the retention set-screws designated 108 and 110. Desired
mutual alignment of the modules is established and maintained by a guide
pin 112 permanently mounted in the center module 104 to project in
opposite directions from the ends thereof and engage in appropriate
recesses in the ends of modules 102 and 106.
Module 102 may be referred to as an injector coupling module, and is
analogous in some ways to the upper portion of the calibration apparatus
50 discussed above. More particularly, the injector coupling module 102
defines an open, generally cylindrical recess portion 114, which may be
disposed at an angle, as shown, with respect to the longitudinal axis of
the overall apparatus to accommodate optical response instruments whose
heads are angled in a complementary manner to facilitate usage. The inner
boundary of recess 114 is an apertured reflector plate 116, whose aperture
arrangement is illustrated in FIG. 7 and includes (in the example under
discussion) four equally-spaced apertures 118, 119, 120 and 121. The
arrangement and sizing of these apertures should be such as to accommodate
the location and size of the light sources and receptors in the particular
probe terminal with which the injector module 102 is designed to mate.
Thus, while the calibration device 50 described above was configured for
use with the particular form of probe terminal 12 illustrated in FIGS. 1
and 2, which has a single fiber-optic bundle 22 as the light-injection
source, the injector coupling 102 is designed to be used with a similar
but somewhat different form of probe terminal (more particularly described
in co-pending application Ser. No. 827,526, filed Feb. 10, 1986), which
has a pair of oppositely-disposed and mutually-spaced fiber-optic bundles
or other light emission means constituting duplicate light-injection
sources, each such cable ending (or other source) being aligned with one
of the openings 119, 121 in the reflector plate 116. The "near" detectors
in the alternate form of probe terminal under discussion are positioned
for alignment with the openings 118, 120 in the reflecting plate, being
equally-spaced along an axis (probe diameter) which is perpendicular to
that along which the light-injection sources are positioned. Thus, the
apertures 118, 119, 120 and 121 in the reflector plate 116 are in effect
arranged in quadrature.
Accordingly, light from the probe terminal injection sources enters the
injector coupling module 102 through openings 119 and 121, and
communicating with those openings is a centrally-located diffusion or
sample chamber 122 established by parllel septa 124 and 126 which extend
as chords across the circular internal cross section of injector module
102, parallel to a diameter thereof (FIGS. 6 and 8). In addition to the
central diffusion chamber 122, the septa 124 and 126 thus also define
oppositely-spaced lateral diffusion chambers 128 and 130, each of which
has one rectilinear side defined by the particular septa involved and one
curvilinear (semi-circular) side defined by the adjacent inner sidewall of
the tubular housing 103 constituting the outer wall of the injector
coupling 102. Chambers 128 and 130 thus are in alignment with the "near"
detector apertures 118 and 120, repectively, noted above. The top of all
three such diffusion chambers is defined by the aforementioned reflector
plate 116 which closes each chamber except to the extent of the apertures
118-120 inclusive, as noted above. A soft, resiliently deformable seal 125
(FIG. 6) seats atop the septa 124 and 126 and extends around the inside
edge of the tubular housing 103 in a shoulder provided there, for mounting
and seating the reflector plate 116 in place atop injector module 102. The
seal 125 also operates to seal the end portions of the optical probe to
the injector module, at the same time sealing the periphery of each
light-injecting or light-detecting optical cable bundle, light source, or
detector in the probe, as the case may be.
The septa 124 and 126 preferably constitute an integral part of a septal
insert 132, which includes a circularly-shaped base portion 134 from which
the septa 124 and 126 project upwardly. Base portion 134 preferably has a
stepped periphery defining a shoulder 135 for closely interfitting with
the complementary end extremities of housing 103, to which the septal
insert should be releasably secured (in any desired conventional manner).
The base portion 134 also defines a generally oval central aperture 136
(FIG. 8) through which part of the injected light may pass, as described
more fully below. Further, each of the parallel septa 124, 126 define a
pair of spaced angularly-disposed, light-passage apertures 138, 138a, and
140, 140a, respectively near the point where the septa join the circular
base 134 (FIGS. 6 and 8), the axis of such apertures preferably being
tilted on an angle of about thirty degrees with respect to the plane of
the base 134, as discussed more fully hereinafter. The opposite end
extremities 125 and 127, respectively (FIG. 8) of the septa 124 and 126
preferably project at least slightly beyond the innermost edge of the
shoulder 135 and are received within closely-fitting corresponding
recesses formed in the inside wall surfaces of the tubular housing 103.
As seen in FIG. 6, each of the two diffusion chambers 128 and 130 includes
an apertured attenuation plate 142, 144, respectively, extending between
the tubular outer peripheral wall of housing 103 and the nearest septa 124
or 126 and located toward the top of each such chamber, a short distance
below the reflector plate 116. Each such attentuaion plate may be mounted
in the desired position by seating in an appropriate slot formed in each
of the septa, as indicated, and the circularly-curved outer periphery of
the attenuation plates should contact the similarly-curved inner wall
surface of the tubular housing 103. Each of the attenuation plates 142,
144 should have a small number (e.g., three) of small apertures 146 (FIGS.
6 and 8), which in a preferred embodiment correlate to the optical
response process described in co-pending application Ser. No. 542,022, are
on the order of about 0.020 inch in diameter and spaced about 0.050 inch
apart.
As already indicated, the injector coupling module 102 seats atop and nests
into the top of the calibrator module 104 (FIG. 6). Basically, the latter
comprises a tubular housing 105 having centrally-apertured closure plates
148, 150 at each opposite end, which may be permanently secured in
position. Preferably, the opposite ends of the tubular housing 105 are
annularly recessed in the manner illustrated, so as to provide an annular
seat for telescopingly receiving the respective ends of the modules 102
and 106. The respective closure plates 148 and 150 are receivable within
such annular recesses, such that the inserted ends of the modules 102 and
106 abut the outer surfaces of the closure plates, with the alignment pin
112 projecting outwardly through each such closure plate, so that its
respective ends 111 and 113 are receivable within complementary recesses
in the end surfaces of the respective modules 102 and 106.
The inner surface of each of the closure plates 148 and 150 defines a
generally rectangular, step-sided recess 149, 151, respectively, (FIGS. 6
and 9). These recesses extend in a first direction toward tubular wall 105
to form a generally rectangular closed (blind) recess 152(a) (FIG. 9), and
also extend in the opposite direction outwardly through one side of the
closure plates and through the adjacent tubular wall 105 to define the top
and bottom of an access opening 152. This opening also includes the entire
rectangular area of tubular wall 105 located between recesses 149 and 151;
that is, such wall portion is also cut away. Accordingly, access opening
152 actually extends through one side of tubular housing 105 and across
the longitudinal axis thereof, along a diameter of the housing and of the
top and bottom closure plates 148 and 150.
The cross-sectional shape of access opening 152 is of a size and shape to
closely receive a sample cell designated 154 in FIG. 6, which may be a
conventional laboratory cuvette. Accordingly, such a sample cell may be
inserted into position within the interior of the calibration module 104
by insertion through the access opening 152 in the tubular wall thereof,
and may be withdrawn from such position in the opposite manner. While in
the inserted position, the sample cell will be disposed in a generally
concentric position intersecting the longitudinal axis of the calibration
module. Both of the closure plates 148 and 150 have a central, axial
aperture, designated 156 and 158, respectively. The upper such aperture
156 is axially aligned with the oval aperture 136 in the injector module
102 when these two modules are fitted together in their nested operating
position, illustrated in FIG. 6. Beneath the lower aperature 158 is
disposed an exit aperture plate 160, which is secured in place over the
circular end opening defined by closure plate 160, as for example by
seating within an appropriate annular recess formed in the edge thereof.
The exit aperture plate 160 is closed at its center, i.e., in alignment
with aperture 158, but it defines a small number (e.g., two) of somewhat
smaller exit apertures 162 and 164 which are radially spaced from is
center, near its outer periphery (FIGS. 6 and 9).
As previously indicated, the detector module 106 (FIG. 6) is received
within the recessed end extremity of the calibrator module 104,
continguous to the exit aperture plate 160 noted just above. Basically,
the detector module 106 is similar in many respects to the injector module
102, except for having no septal insert. Instead, detector module 106
basically comprises a tubular housing 107 which is received within the
recessed end extremity of calibrator module 104, contiguous to the exit
aperture plate 160. Preferably, detector module 106 has an appropriate
guide opening formed in the upwardly-facing end extremity of its tubular
housing 107, to receive the projecting end extremity 113 of the guide pin
112, and in this manner a desired orientation of the detector module may
be obtained analogous to the orientation of injector module 102.
The detector modules 106, while having no septal insert, nonetheless should
have a reflector plate 166 at its lower end opening. Reflector plate 166
is analogous to reflector plate 116, at the inlet to the injector module
102, and may be similarly seated upon a soft, resilient elastomeric seal
168 of an annular shape. While similar or analogous to the inlet reflector
plate 116, the exit or outlet reflector plate 166 should have an array of
outlet apertures 170 whose size, shape, and pattern is representative of
the optical probe member or probe terminal with which the detector module
is to mate. Generally speaking, such an optical probe may be expected to
have the characteristics of the probe terminal 14 illustrated in FIGS. 1
and 3 hereof, although it is to be noted that other arrangements and
details for optical probe terminals with which the present invention is
equally usable are certainly possible. One such alternate form of probe
terminal is shown in the above-noted co-pending application Ser. No.
827,526, which is commonly owned with the present application. The
characteristics of such a probe may include optical cable endings used
directly as light receptors, rather than the electrically-operative
photo-voltaic cells or photo-diodes referred to above in connection with
the apparatus of FIG. 3. Of course, the light received by such a direct
cable-end receptor will typically be coupled to | | |
