Method and apparatus for detecting extraneous solid substances contained in liquid

An improvement of a method and an apparatus for detection of an extraneous solid substance which may exist in a transparent liquid wherein a sealed transparent container filled with the transparent liquid is rotated to cause rotation of the extraneous solid substance mixed and floated in the liquid. Light is projected through the container and the intensity of the light passed through said container is measured. The invention is characterized in that an optical fiber line-circle converter has its linear end formed into two or more straight files which may be set on the same or different level lines, respectively. The present method and apparatus can detect more precisely the extraneous substance moving in an irregular motion in the transparent liquid.

The present invention relates to a method for inspecting an extraneous 
solid substance which may exist in a transparent liquid filled in a sealed 
transparent container. 
BACKGROUND OF THE INVENTION 
For inspecting solids which may exist in a liquid such as medicine, food 
and drink, cosmetic, chemicals, reagent or the like, filled in sealed, 
transparent containers, for example, ampoules, vials, bottles or the like, 
and to select the containers, there are known various methods for 
inspection the liquid utilizing the photoelectric element rather than 
relying simply on the a naked eye inspection. 
Among these known methods for inspecting a liquid, the present invention 
attempts to improve the liquid testing method for determining the 
intensity of a penetrated light wherein light is projected, for example, 
through an ampoule) by measuring the degree of the screening of said light 
due to extraneous substances existing within a liquid by a photoelectric 
element. In such a case the light is screened by extraneous substances and 
the light received by the photoelectric element is decreased relative to 
the amount that is present when an extraneous substance is absent. 
Therefore, whether the amount of extraneous substances in a liquid is 
large or small, can be determined according to the decrease of light 
received by the photoelectric element. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a means whereby it is possible to 
precisely detect the extraneous substances being moved in a peculiar 
motion in the liquid. Namely, the present invention relates to a method 
for detecting the existence of solids in a transparent liquid by rotating 
a sealed, transparent container filled with a transparent liquid, to 
rotate solids which may exist in the liquid, projecting light in to the 
container, and measuring the intensity of the light which is passed 
through said container and not intercepted due to the substances. The 
method is characterized in that a linear end of an optical fiber 
line-circle converter is formed into two or more straight files. 
Another object of this invention is to provide an optical fiber line-circle 
converter which is constructed to avoid the dispersion of brightness 
caused by the varied position of the substance to be detected in the 
container, and which has in particular, linear ends formed into an even 
number of straight files. 
A further object of this invention is to provide an optical fiber 
line-circle converter capable of detecting more precisely an extraneous 
solid substance moving in peculiar motions, which comprises forming a 
linear end of said converter into two or more files set on different level 
lines respectively, so that the image of the extraneous substance can be 
received at different distances from the image lens.

DETAILED DESCRIPTION OF THE INVENTION 
In the arrangement diagram shown in FIG. 1, a lamp or light projecter 1 is 
lighted to provide parallel rays of light from a condenser lens 2 placed 
in front thereof, and the parallel rays of light are projected against an 
ampoule 12 to be inspected which is 3. The turntable 3 is rotated at a 
high speed and then stopped suddenly, so that extraneous substances 
existing in the ampoule fixed on the turntable are rotated together with 
the liquid in the ampoule. Projected images of the extraneous substances 
are then made on the straight ends 5 and 5' of optical fiber 6 of a 
scanner 11 by an image lens 4, which interrupt the direct rays of light 
from the lamp 1 thrown onto the light-receiving faces of the optical 
fibers. Thus, darkened areas caused by the screening of the projected 
light is transmitted to the circular end 7 through the optical fibers 6. 
The condition of the circular end 7 is minutely picked up by a rotating 
scan head 8, and transmitted to the light-receiving face of a 
photoelectric element 9 where it is there converted into electrical pulse 
signals. The amplified signals are produced in an amplifier 10. Thus, the 
presence of an extraneous solid substance in the ampoule is detected and 
converted to electrical pulse signals. By utilizing these signals the 
selection of the ampoule on the basis of solid impurities can be carried 
out. 
In the scanner, a plurality of minute light-receiving faces are arranged in 
a straight lines. These light-receiving faces each have an area at least 
corresponding to the size of the image of the extraneous substance 
predetermined as the minimum limit to be caught by a bundle of the optical 
fibers of the optical fiber line-circle converter. The faces are arranged 
in a straight file, which is so made up that scanning is carried out in 
turn on these minute light-receiving faces one by one. 
The optical fiber system scanner will be described with reference to the 
enlarged, oblique view in FIG. 2. FIG. 2 shows an embodiment of the 
scanner 11 equiped with an optical fiber line-circle converter utilizable 
in the scanner, in which converter the light-receiving portions thereof 
are arranged for two straight files. This optical fiber system scanner has 
a number of optical fibers 6, for example as slender as 100.mu. in 
diameter, a rotary scanning head 8 and a photoelectric element 9. These 
plural optical fibers are at one end thereof arranged into two straight 
files, i.e. linear end 5 and 5', and at the other end the fibers are 
arranged circularly so as to form a circular end 7 (a line-circle 
conversion structure). One end of the rotary scanning head 8, which is 
made of optical fiber, rotates and scans along said circular end 7 and the 
other end of this scanning head 8 is optically connected to the 
light-receiving face of the photoelectric element 9. Through an ampoule, 
which has come to a sudden stop from a high speed rotation, the light from 
the light source is thrown to the light-receiving faces of minute cross 
section in the linear ends 5 and 5', and gives a constant brightness to 
the light-receiving faces. When the projected image of any extraneous 
substance existing in the ampoule crosses the linear ends 5 and 5', the 
light-receiving faces of the optical fibers are darkened, because the 
direct rays of light from the source are screened by the extraneous 
substances. Such a bright or dark state at the linear ends 5 and 5' is 
transmitted to the circular end 7 through the optical fibers 6, and the 
rotating scanning head 8 picks up the brightness and darkness of each one 
of the optical fibers at the circular end 7 while it is rotated. These 
conditions are then converted to the intensity of an electric current by 
the photoelectric element. Based on these electrical signals, the 
inspection and selection of the object may be carried out properly in a 
known manner. 
According to the above-mentioned embodiment of the present invention, the 
screening of the light on the light-receiving faces of the optical fibers 
due to the extraneous substances is utilized for measurement and, 
therefore, signals having a higher S/N ratio can be obtained even when an 
extraneous substance having a small refractive power exists, whereby a 
highly accurate determination can be achieved. Since the size of the 
projected image which is the same as the diameter of each one of the 
optical fibers is the size of the minimum extraneous substance which can 
be detected, the minimum size of a catchable extraneous substance can be 
freely changed by adjusting the magnification of the image lens. 
In FIG. 3, the files A and B may be directly adjacent to each other or 
interruped by, for example, a fixed means etc. 
When it is desired to detect a minute extraneous substance having for 
example a minimum size of 10.mu., an optical fiber having corresponding 
diameter, 10.mu., should be employed. However, the smaller the optical 
fiber is, the more difficult it is to manufacture the scanning device. 
Then, the detection is achieved generally by optically enlarging the image 
of the minute extraneous substance. In such a case, there can not be 
avoided lowering of focal depth due to the optical enlargement, and so, it 
is difficult to detect the minute extraneous substance moving to change 
the position thereof. 
In the present invention, since there is provided a level difference H, 
which may be selectively determined between the light-receiving faces of 
the linear end A and that of B, it is possible to receive an image of the 
extraneous substance at two positions different in the distances from the 
image lens, respectively. Even when the focal depth is lowered by optical 
enlarging, it is easier to focus on the image, because it is possible to 
focus at two or more points. 
Also, when the extraneous substance is moved by a distance equal to the 
radius of the container to be inspected, an optical image of the 
extraneous substance can be clearly focussed either the end A or the end 
B; that is, the focusing area of the extraneous substance can be extended. 
Thus, the present method exhibits an excellent effect for the precise 
detection of the extraneous substance moving in an irregular motion. 
According to the foregoing statements, the present invention is 
characterized in that the light-receiving portions of an optical fiber in 
an optical fiber line-circle converter are at one end arranged in two or 
more straight files of linear displacement so that a large number of the 
optical fibers 6 may be used and, therefore, the number of chances for 
catching the light received on the optical fibers in every single 
revolution of a rotating scan head is increased. It may be expected in 
this invention that substantially the same effect is obtained as that 
achieved when the revolutions of the rotary scanning member are increased 
as compared with a conventional scanner in which the ends of optical 
fibers are formed into an single linear end. Additionally, in this 
invention two or more plural lines having linear ends are formed so that 
the number of light-receiving positions for the object is increased, thus 
providing many chances of catching the images of extraneous substances in 
accordance with the increased number of said positions. Moreover, the 
measurement does not undergo any influence of the dispersion in brightness 
effected by the position of the object. For example, when there is the 
dispersion in brightness between the upper portion and lower portion of 
the object, in a conventional scanner having a single linear end, the 
difference of brightness between the upper and lower portions of the 
object is immediately shown in electrical signals, which is apt to be 
mistaken for the signals based upon the extraneous substances, because the 
optical fiber of the lowermost end and the optical fiber of the uppermost 
end at the linear end 5 and 5', are adjacent to each other on the circle 
end 7. On the other hands, the present invention does not undergo the 
influence of the dispersion in brightness, because the optical fiber 
line-circle converter has one end thereof into two or more files, then, 
for example, in cases of the two lines of linear ends, the optical fiber 
line-circle converter can be made into a structure such that an optical 
fiber of the uppermost end in the first line of the linear end and the one 
of uppermost end in the second line, and then the lowermost end in the 
second column and the lowermost end in the first column are respectively 
adjacent to each other at the circular end. 
As described above, the desirable effects are obtained by forming the 
linear end of the optical fiber line-circle converted into even number of 
files.