Automatic microfilm retrieval system

An automatic microfilm retrieval system for retrieving contents of a dictionary or the like recorded on a microfilm and displaying them on a screen is disclosed. Said microfilm includes a retrieval cord and divided into a plurality of unit regions to be displayed on said screen at the same time and further includes a cord added to each of said unit regions and representing an index word whose contents are included in each of said unit regions. A plurality of said unit regions are assembled into a plurality of groups. To each of said groups are added cords representing first and last index words included in each of said groups. Provision is made of a subtracter which functions to compare said cords read out by a reading head with key inputs obtained by depressing keys provided on a key board and control movements of a movable stage holding said microfilm thereon, thereby retrieving said microfilm.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an automatic microfilm retrieval system which 
makes use of a microfilm bearing contents of a dictionary or the like 
recorded thereon and which can automatically retrieve a film portion 
bearing an index word in response to an input signal obtained by 
depressing keys. 
2. Description of the Prior Art 
Heretofore it has been the common practice to record an English-Japanese 
dictionary, for example, on a microfilm in a reduced scale, automatically 
retrieve a microfilm portion bearing a desired index word by depressing 
keys corresponding to such index word and project the retrieved microfilm 
portion on a screen in an enlarged scale. In this case, it is important to 
carry out successive steps of depressing the keys corresponding to the 
desired index word and retrieving the film portion bearing the index word 
in a rapid and reliable manner with the aid of a device which is simple in 
construction. 
In the conventional microfilm retrieval system, in order to obtain a signal 
for retrieving a film portion, a signal representing the relation between 
an index word and a microfilm portion bearing the index word recorded 
thereon must be stored beforehand in a memory. This signal thus stored in 
the memory causes the index word corresponding to the depressed keys to 
convert into a signal corresponding to the microfilm portion bearing the 
index word and this signal is used for retrieving the microfilm. 
In such conventional system, it is indispensable to use the memory, so that 
the system becomes complex in construction and very troublesome in 
operation of storing beforehand the above mentioned signal in the memory, 
that the system is constructed such that at first the input signal 
produced by depressing the keys is converted into a position representing 
signal and then the signal thus converted is used to retrieve the 
information on the microfilm, thereby limiting the retrieving speed, and 
that, in the case of replacing the existing microfilm by another kind of 
microfilm, provision must be made of a memory corresponding to such 
microfilm. 
SUMMARY OF THE INVENTION 
An object of the invention, therefore, is to provide an automatic microfilm 
retrieval system which can retrieve informations recorded on a microfilm 
in a rapid and reliable manner without requiring any memory and hence is 
simple in construction. 
A feature of the invention is the provision in an automatic microfilm 
retrieval system comprising a stage movable in X and Y directions, a 
microfilm disposed on said stage and bearing contents of a dictionary or 
the like recorded thereon, an optical system and reading head arranged 
above and opposed to said microfilm, a screen and a key board provided 
thereon with a number of keys corresponding to index words to be 
retrieved, a microfilm portion corresponding to index words selected by 
depressing said keys being projected on said screen, the improvement 
comprising a retrieval cord recorded on said microfilm, the surface of 
said microfilm being divided into a plurality of unit regions to be 
displayed on said screen at the same time, a cord added to each of said 
unit regions and representing an index word whose contents are included in 
each of said unit regions, a plurality of said unit regions being 
assembled into a plurality of groups, cords added to each of said groups 
and representing first and last index words included in each of said 
groups, and a subtracter comparing said cords read out by said reading 
head with key inputs obtained by depressing said keys and controlling 
movements of said stage and retrieving said microfilm disposed thereon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows one embodiment of an automatic microfilm retrieval system 
according to the invention. In the present invention, if keys 1a of a key 
board 1 corresponding to the spelling of an index word to be selected are 
depressed, a stage 3 with a microfilm 2 disposed thereon is moved in X and 
Y directions so as to bring the index word selected by the depressed keys 
1a into alignment with the optical axis of an optical system 4 and the 
contents of a dictionary or the like recorded on the microfilm 2 is 
projected on a screen 5. 
More particularly, on the microfilm 2 are recorded not only the contents of 
the dictionary or the like but also retrieval bar-cords to be described 
later. These retrieval bar-cords are read out by a bar-cord reading 
mechanism 6 so as to effect the retrieval operation. In addition, the 
optical system 4 is connected to an automatic focus adjusting mechanism 7 
which functions to automatically bring the image projected on the screen 3 
in focus. The key board 1 is also provided with an OK key to be described 
later. 
FIG. 2 shows the microfilm 2 shown in FIG. 1. An embodiment in which an 
English-Japanese dictionary of 1395 pages is recorded on a microfilm 
(microfiche) of 100.times.125 mm.sup.2 (effective size of 90.times.115 
mm.sup.2) in a reduced scale will now be described. In this case, a rate 
of reduction is 1/43 and each half page 10-1-1, 10-1-2, ) . . . of the 
dictionary is recorded on the microfilm 2. Each half page is divided into 
substantially four square regions. But, each half page is not always 
divided into four regions depending on the arrangement of letters. One of 
these four square regions is projected on one visual field of the screen 
5. 
In the present embodiment, at the side of each square region is arranged a 
first bar-cord 11-1, 11-2 . . . representing the spelling of a first index 
word included in each square region. Such first bar-cord may represent a 
main index word included in each square region instead of the first index 
word included in each half page. This first bar-cord is composed of 100 
bits, 1 bit being represented by black and white, for example. Since 
English alphabet consists of 26 letters, 1 letter can be expressed by 5 
bits, and as a result, the first bar-cord can represent one word 
consisting of at most 20 letters which are sufficiently long letters for 
the English-Japanese dictionary. 
Then, on the microfilm 2 are recorded second bar-cords 12-1-1, 12-1-2, . . 
. , each composed of 200 bits with respect to each half page 10-1-1, 
10-1-2, . . . , composed of a group of four square regions. First 100 bits 
A of the second bar-cord represent the first index word of each half page 
and succeeding 100 bits B represent the last index word of each half page. 
Near each of these second bar-cords is arranged a stop signal S which is 
used for determining a retrieval position. In addition, provision is made 
of a third bar-code for each line of the half page, that is, provision is 
made of a third bar-cord 13-1, 13-2, . . . composed of 200 bits for one 
line of the half page 10-1-1, 10-1-2, . . . , 10-1-n, a third bar-cord 
13-2 composed of 200 bits for the next line of the half page 10-2-1, 
10-2-2, . . . , 10-2-n. 
Similar to the above described second bar-cords for each half page, in the 
case of line 1, for example, the first 100 bits A of the third bar-cord 
13-1 represent the first index word of the first half page 10-1-1 and the 
succeeding 100 bits B represent the last index word of the last half page 
10-1-n. Near each of these third bar-cords is arranged the stop signal S. 
The measures similar to the above are also taken for the succeeding lines. 
Each of the above described bar-cords is arranged along the retrieval 
direction. 
In the present invention, the microfilm 2 bearing the contents of the 
dictionary and bar-cords is used for the purpose of automatically 
retrieving the contents of the dictionary in the following manner. In the 
first place, let it be assumed that the bar-cord reading mechanism 6 is 
located at a position on the film 2 designated by reference numeral 14 in 
FIG. 2. If the English word "GREEK" is to be retrieved, for example, at 
first, that key 1a of the keyboard 1 which corresponds to a letter "G" is 
depressed. As a result, the microfilm 2 is moved in a direction shown by 
an arrow Y to cause the reading mechanism 6 to read out the third bar-cord 
13-1. As described above, each bar-cord is arranged along the moving 
direction of the microfilm 2, so that any other scanning for reading out 
the bar-cords is not required. As described above, in the third bar-cord 
13-1 are written the first and last index words of the first and last half 
page of the dictionary. If an index word beginning from "G" is included in 
the line 1 from 10-1-1 to 10-1-n, the movement of the microfilm 2 in the Y 
direction is stopped at the line 1. 
If the index word beginning from "G" is not included in the line 1 from 
10-1-1 to 10-1-n, the microfilm 2 is further moved in the Y direction to 
cause the reading mechanism 6 to read out the third bar-cord 13-2 on the 
line 2. If the index word beginning from "G" is not included in the line 
2, the microfilm 2 is still further moved in the Y direction. In this way, 
the microfilm 2 is continuously moved. If the index word beginning from 
"G" is included in the line m from 10-m-1 to 10-m-n, for example, the 
movement of the microfilm 2 in the Y direction is stopped at the position 
of the stop sign S on the line m. 
FIG. 3 shows the line m and its vicinity in an enlarged scale. If a key 1a 
corresponding to "R" is depressed, the input letters obtained by 
depressing the key become "GR". 
If the index word beginning from "GR" is not included in the line m, the 
microfilm 2 is further moved in the Y direction to cause the reading 
mechanism 6 to read out the third bar cord 13-(m+ 1) ) on the line (m+1). 
If the index word beginning from "GR" is included in the line (m+1), the 
movement of the microfilm 2 in the Y direction is stopped at the position 
of the stop sign S. 
As shown in FIG. 3, the line (m+ 1) includes therein index words from "GIVE 
AND TAKE" to "HAIR", so that the index word beginning from "GR" is not 
included in the line (m+ 1) at all. As a result, the microfilm 2 is moved 
in the X direction and stopped at the half page 10-(m+ 1)-23 including 
therein the word beginning from "GR". 
Then, the key corresponding to "E" is depressed to obtain an input "GRE". 
If the input becomes "GRE", the microfilm 2 is further moved in the X 
direction to cause the reading mechanism 6 to read out second bar-cords 
12-(m+ 1)-24, 12-(m+ 1)-25, . . . corresponding to each half page. If the 
index word beginning from "GRE" is included in the half page 10-(m+ 1)-34, 
the movement of the microfilm 2 in the X direction is stopped at the 
position of the stop signs S of the second bar-cord 12-(m+ 1)-34 
associated with the half page 10-(m+ 1)-34. If a key corresponding to "E" 
is depressed, an input "GREE" is obtained. If an index word beginning from 
"GREE" is not included in the half page 10-(m+ 1)-34, the microfilm 2 is 
further moved in the X direction to cause the reading mechanism 6 to read 
out a second bar-cord 12-(m+ 1)-34 associated with the half page 10-(m+ 
1)-34. If the index word beginning from "GREE" is included in the next 
half page 10-(m+ 1)-35, the movement of the microfilm 2 in the X direction 
is stopped at the position of the stop sign S of the second bar-cord 
12-(m+ 1)-35 associated with the next half page 10-(m+ 1)-35. 
If a key corresponding to "K" is depressed, an input "GREEK" is obtained. 
In this case, it is uncertain whether or not an index word beginning from 
"GREEK" is included in this half page or becomes deviated from this half 
page when the next key is depressed, so that the microfilm 2 is not moved. 
If a key "OK" showing the absence of the key input is depressed, it is 
found out that "Greek" is included in this half page 10-(m+ 1)-35. Then, 
the microfilm 3 is moved again in the Y direction to retrieve this half 
page and is stopped at a first bar-cord 11-K showing "GREEK". 
If the bar-cord which coincides with the key input is absent, the microfilm 
2 is stopped at a position where the input cord exceeds the bar-cord. 
After the above described automatic retrieving operation has been 
completed, the retrieved portion is projected on the screen 5. 
The above described movement of the microfilm 2 is controlled in the 
following manner. As shown in FIG. 4, each bar-cord represents each letter 
such that the first 5 bits represent the capital letter and that the next 
succeeding 5 bits represent the 2nd letter. To each letter is assigned a 
binary number in the order of ABC and these numbers constitute cords for 
each letter. The letters supplied as the key input are coded in the same 
rule. The cords supplied as the key input is subtracted from the first 10 
bits of the bar-cord with respect to a number of figures of the letters 
supplied as the key input, for example, with respect to the input 
2.times.5=10 bits when the two letters "GR" are supplied as the input and 
the movement of the microfilm 2 is controlled on the basis of a positive 
value, negative value or zero resulted from the subtraction. 
But, at the end of the input, if the "OR" key is depressed, operation on 
the total figures of the bar-cord may be effected. 
As described above, the movement of the microfilm 2 is classified into the 
following three conditions. 
(1) The microfilm 2 is rectilinearly moved in X or Y direction. 
(2) The microfilm 2 changes its direction of movement from X direction to Y 
direction or vice versa. 
(3) The microfilm 2 becomes stopped to await the next key input. 
The movement of the microfilm 2 under the above conditions can be 
controlled in the following manner. 
If the bar-cord such as the second bar-cord for each half page and the 
third bar-cord for each line is composed of two bar-cords A, B, at first 
the bar-cord A is subtracted from the input cord and then the bar-cord B 
is subtracted from the input cord. If the remainder of the former 
subtraction is positive and the remainder of the latter subtraction is 
negative, the index word is present on the half page corresponding to the 
second bar-cord or on the line corresponding to the third bar-cord. As a 
result, the direction of movement of the manuscript 2 is changed from the 
direction Y to the direction X and vice versa and then the microfilm 2 is 
continuously moved. If both the remainders of the former and latter 
subtractions are positive, the wanted index word is present on the 
succeeding half page or line. As a result, the rectilineal movement of the 
microfilm 2 is continued. 
If the remainder of the former subtraction is positive and the remainder of 
the latter subtraction is zero or both the remainders of the former and 
latter subtractions are zero, it is uncertain whether or not the index 
word is present on the half page or line concerned. As a result, the 
microfilm 2 is stopped to await the next key input. Next, if the microfilm 
2 is moved in the Y direction in each half page, the first par-cord 
represents only one index word. As a result, if the remainder of the 
subtraction of the bar-cord from the input cord is positive, the movement 
of the microfilm 2 is continued. If the remainder of the subtraction of 
the bar-cord from the input cord is negative or zero, the microfilm 2 is 
stopped. 
FIG. 5 shows a block diagram of one embodiment of the above described 
automatic microfilm retrieval system according to the invention. The 
spelling of an input index word obtained by depressing a key 1a of a key 
board 20 is supplied to an encoder 21 which functions to convert the index 
word into a cord which is then stored in a register 22. A bar-cord signal 
on a microfilm read out by a bar-cord reading mechanism 23 is supplied to 
a memory 24 which functions to store the bar-cord signal therein. The 
content of the register 24 and the content of the memory 24 are delivered 
to a subtractor 25 which functions to subtract the content of the memory 
24 from the content of the register 22. 
As described above, the number of figures of the operation is controlled by 
whether or not an OK key 26 is depressed. The remainder of this 
subtraction is delivered to a stage movement controller 27 which functions 
to operate a stage driving device 28 so as to move the stage 3 shown in 
FIG. 1. 
In the present embodiment, the retrieval operation is started from a 
position 14 shown in FIG. 2 and located at the upper left end of the 
microfilm 2. It is not always necessary to start the retrieval operation 
from the position 14. It is possible to start the retrieval operation from 
any desired position on the microfilm 2. In this case, if the remainder of 
the subtraction effected in the subtracter 25 is negative, this negative 
value causes the stage movement controller 27 to reverse through the stage 
driving device 28 the movement of the stage 3. It is preferable to 
manually retrieve the index word when a number of index words each having 
the same spelling are arranged side by side on the microfilm 2. 
In the present embodiment, the key input has been supplied to the system 
after the end of the stage movement for the sake of convenience in 
explanation, but all of the key inputs corresponding to the spelling of 
one index word may be supplied at the same time without awaiting the end 
of the stage movement and the OK key 26 may be depressed. 
The above mentioned control operations may easily be carried out with the 
aid of a microcomputer. 
The following Table 1 shows a capacity of a microfilm having a size of 
100.times.125 mm.sup.2 and bearing an English-Japanese dictionary recorded 
thereon with rates of reduction of 1/43 and 1/70, respectively. 
Table 1 
______________________________________ 
Microfilm size 100 .times. 125 mm.sup.2 
Microfilm effective size 
90 .times. 115 mm.sup.2 
Dictionary size (1 page) 
80 .times. 155 mm.sup.2 
Rate of reduction 
1/43 1/70 
Size of 1 page on 
1.86 .times. 3.6 mm.sup.2 
1.14 .times. 2.2 mm.sup.2 
microfilm 
Number of pages included 
1,395 3,600 
on 1 microfilm 
______________________________________ 
As seen from the Table 1, one volume of the English-Japanese dictionary is 
included on one microfilm with the rate of reduction of 1/43. 
The following Table 2 shows the minimum line width of a letter used in the 
dictionary and a letter used in newspapers. 
Table 2 
______________________________________ 
Dictionary 
Newspaper * 
______________________________________ 
Minimum line width 
60 .mu.m 120.mu.m 86 .mu.m 
Length of letter 
1.3 mm 1.8 mm 1.3 mm 
______________________________________ 
In the above Table 2, numerical values mentioned in the right column * are 
the minimum line width and length of letter of that letter in the 
newspaper which is reduced to the letter in the dictionary. As seen from 
the Table 2, it is clear that the letter in the newspaper is larger in 
width than the letter in the concise dictionary. 
The following Table 3 shows the relation between the resolution and the 
visual field on respective reading objective lenses having magnifications 
of 20X and 40X, respectively. 
Table 3 
__________________________________________________________________________ 
Reading objective lens 
20X 40X 
__________________________________________________________________________ 
NA 0.4 0.63 
Reading out 
Number of visual fields 
30 mm 30 mm 
One side of square 
21.2 mm 21.2 mm 
visual field 
Real visual field 
1.06 mm 0.53 mm 
Minimum line width 
60 .mu.m 
86 .mu.m 
60 .mu.m 
86 .mu.m 
of letter 
Writing in 
Resolvable rate of 
1/30 
1/43 1/49 1/70 
reduction 
One side length of 
31 mm 
45 mm 
25.9 mm 
37.1 mm 
original visual field 
__________________________________________________________________________ 
As seen from the Table 3, if use is made of an objective lens having 20X 
and number of visual field of 30 mm, then it is possible to record the one 
side of the original at most 31 mm with 60 .mu.m of the minimum line width 
of the letter and record the one side of the original at most 45 mm with 
86 .mu.m of the minimum line width of the letter. As a result, it is 
necessary to use a letter whose minimum line width is at least 86 .mu.m in 
order to record one side of 40 mm of the dictionary on the microfilm. 
Thus, it is possible to prepare a microfilm by using reduced newspaper 
letters. If the dictionary letter per se is used, an objective lens having 
20X and number of visual field of 37 mm must be designed. The capacity of 
the microfilm for including the dictionary letters therein becomes 1/2 
times smaller than that of the present embodiment. In addition, the 
longitudinal letter line is wider in width than the transverse letter 
line, so that it is possible to increase the capacity of the microfilm for 
including the letters thereon by recording the longitudinal letter line 
with a rate of reduction which is two times larger than that of the 
transverse letter line. This can be effected by a lenticular lens arranged 
in the transverse direction. 
FIG. 6 shows one modified embodiment of the microfilm shown in FIGS. 2 and 
3. 
In the present embodiment, each half page 30-1, 30-2, . . . is divided into 
four regions 31-1, 31-2, . . . each constituting the minimum unit. These 
four regions 31-1, 31-2, . . . are provided with bar-cords 32-1, 32-2, . . 
. and bar-cords 33-1, 33-2, . . . , respectively. One bar-cord is used as 
a reading bar-cord when the retrieval operation in the Y.sub.1 direction 
is effected, while the other bar-cord is used for reading bar-cord when 
the retrieval operation in the Y.sub.2 direction is effected. In addition, 
each column 34-1, 34-2, . . . of the four regions constitutes a group. 
Each group is provided with two bar-cords 35-1, 36-1, . . . and 35-2, 
36-2, . . . , respectively, either of these two bar-cords may be read out. 
In the present embodiment constructed as above described permits to start 
the retrieval operation from any position on the microfilm 2. In the above 
described embodiment, use has been made of a microfiche as the microfilm, 
but a strip-shaped microfilm may also be used. In addition, in the above 
described embodiment, provision has been made of a bar-cord corresponding 
to the first index word to each divided region, but provision may also be 
made of bar-cords corresponding to the first and last index words. 
As stated hereinabove, the system according to the invention has a number 
of advantages. In the first place, it does not require any memory for 
converting the key input into a position signal and hence is simple in 
construction and does not require any troublesome operation of preparing 
the contents stored in the memory. Secondly, the system does not require 
any special scanning mechanism for reading out the bar-cords and hence is 
simple in construction. Third, the system can judge the retrieval 
operation by the key input concerned in the course of the retrival 
operation and hence can effect the automatic retrieval operation at a high 
speed. Finally, the retrieval cords are recorded together with the 
contents of the dictionary on the microfilm, so that any operation other 
than the film changing operation is not required when the microfilm is 
changed into a new one. 
FIG. 7 shows another modified embodiment of the microfilm shown in FIGS. 2 
and 3. In the present embodiment, a page 40 of an English-Japanese 
dictionary bearing letters whose longitudinal line is larger in width than 
the transverse line is recorded on a microfilm. In the first place, as 
shown in FIG. 7, the left and right columns of half page of the dictionary 
40 are divided into 8 original visual fields 41, each having a transverse 
length of 40 mm and a longitudinal length of 20 mm. 
Then, as shown in FIG. 8, the above mentioned one original visual field 41 
is reduced into 1/2 scale in the transverse direction only with the aid of 
a cylindrical lens to obtain a square visual field. This square visual 
field is then reduced with a rate of reduction of 1/30 and the reduced 
visual field thus obtained is recorded on a microfilm. In FIG. 8, the 
visual field reduced to 1/30 scale is shown in an enlarged scale. 
Even though the transverse width of the original visual field 41 is reduced 
into 1/60 scale and the longitudinal width thereof is reduced into 1/30 
scale, the longitudinal line width is at least 2 times larger than the 
transverse line width, so that the reduced original visual field can be 
reproduced into a sufficiently enlarged scale by means of an objective 
lens having a magnification of 20X. In addition, in this case, use may be 
made of an objective lens having a visual field number of 19 mm, that is, 
use may be made of a microscope lens in general. 
If a dictionary is recorded on a microfilm in the manner as above 
described, it is possible to include 1455 pages of the dictionary in one 
sheet of the above mentioned microfilm having the size of 100.times. 125 
mm.sup.2 with an extremely high record density. FIG. 9 shows an optical 
lens for effecting the recording step shown in FIG. 8 and FIG. 10 shows an 
optical lens for reproducing an information recorded on a microfilm on a 
screen. A recording optical lens shown in FIG. 9 is composed of a 
reflecting member 53, a cylindrical lens 54 for effecting a 1/2 reduction 
in the transverse direction only and a camera optical system 55 for 
effecting a 1/30 reduction in both longitudinal and transverse directions. 
The image of one original visual field 41 is recorded through the 
reflecting member 53, cylindrical lens 54 and camera optical system 55 on 
a microfilm 6 with a transverse reduction rate of 1/60 and a longitudinal 
reduction rate of 1/30. 
The reproducing optical lens shown in FIG. 10 is composed of a projection 
optical system 57 for effecting magnification of 20X in longitudinal and 
transverse directions, reflecting member 8, cylindrical lens 59 for 
effecting magnification of 2X in the transverse direction only and screen 
60. The information recorded on the microfilm 56 is reproduced and 
projected through the projection optical system 57, reflecting member 58 
and cylindrical lens 59 on a screen 60. That is, the reproduction optical 
system is composed of a lens system having a ratio between longitudinal 
and transverse magnifications which is an inverse number with respect to a 
ratio between longitudinal and transverse reduction rate used when the 
image of one original visual field 41 is recorded on the microfilm 56. 
As stated hereinbefore, the present embodiment permits to record the image 
of one original visual field 41 on the microfilm 56 with a rate of 
reduction which is larger in the transverse direction than in the 
longitudinal direction based on the recognition that in general letters, 
signs, etc. have a longitudinal line which is wider in width than a 
transverse line. As a result, the record density per unit area of the 
microfilm becomes large. In addition, when the record on the microfilm is 
reproduced on the screen, it is possible to use a magnifying lens having a 
small visual field number, thereby making the reproduction optical system 
less expensive. 
Left and right columns of half page of the English-Japanese dictionary may 
be divided into 8 original visual fields, respectively, each having one 
side of 40 mm in length. In this case, one original visual field is 
reduced in the transverse direction into 1/2 scale and then is reduced in 
both the longitudinal and transverse direction into 1/30 scale. As a 
result, it is possible to include 1455 pages on one microfilm having a 
size of 100.times. 125 mm.sup.2. In addition, the information thus 
recorded on the microfilm can be reproduced in an enlarged scale with the 
aid of an objective lens having a magnification of 20X and visual field 
number of 30 mm. 
FIG. 11 shows another embodiment of an automatic microfilm retrieval system 
according to the invention. In the present embodiment, if keys 1a of a key 
board 1 corresponding to the spelling of an index word to be selected are 
depressed, a stage 3 with a microfilm 2 disposed thereon is moved in X and 
Y directions so as to bring the index word selected by the depressed keys 
1a into alignment with the optical axis of an optical system 4 and the 
contents of a dictionary or the like recorded on the microfilm is 
projected on a screen 5. At the same time, the pronunciation of the index 
word is effected from a speaker 70. 
FIG. 12 shows a block diagram of the system shown in FIG. 11. The spelling 
of an input index word obtained by depressing a key 1a of a key board 1 is 
supplied to an encoder 21 which functions to convert the index word into a 
cord which is then stored in a register 22. A bar-cord signal on a 
microfilm read out by a cord reading mechanism 23 is supplied to a memory 
24 which functions to store the bar-cord signal therein. The content of 
the register 22 and the content of the memory 24 are delivered to a 
subtractor 25 which functions to subtract the content of the memory 24 
from the content of the register 22. 
As described above, the number of figures of the operation is controlled by 
whether or not an OK key 26 is depressed. The remainder of this 
subtraction is delivered to a stage movement controller 27 to operate a 
stage driving device 28 so as to move the stage 3 shown in FIG. 11. 
In the present embodiment, the cord of the index word delivered from the 
key board 20 and stored in the register 22 is supplied to a phonetic sign 
memory 70 which functions to convert the cord of the index word into an 
array of the phonetic sign cords. That is, the phonetic sign memory 79 
functions to store the cord of the phonetic sign of each index word. If a 
cord corresponding to the English word "phoneme", for example, is stored 
in the register 22, a cord corresponding to "founi:m" is delivered from 
the phonetic sign memory 79 to a sound synthesizer 80. The sound 
synthesizer 80 is of a well known one which functions to pronounce a 
phonetic sign which is delivered thereto. The output from the sound 
synthesizer 80 is supplied through an amplifier 81 to a speaker 70 which 
functions to pronounce the contents stored in the register 22, that is, 
pronounce the index word selected by depressing the keys. In the case of 
English language, for example, the number of the phonetic signs inclusive 
of stress sign, etc. is about 60, so that the pronouncing mechanism 
becomes relatively simple in construction. 
In the present embodiment, the index word per se corresponding to the key 
input obtained by depressing the key has been pronounced. Alternatively, 
one portion of the content corresponding to the index word may also be 
pronounced. 
As stated hereinbefore, the present embodiment can store the phonetic sign 
only necessary for phonetically synthesizing in the sound synthesizer 80, 
so that it is possible to make the store capacity small and as the memory, 
a magnetic bubble, semiconductor memory, etc. may be used and hence the 
system becomes small in size. In addition, the system requires few 
mechanically operable members and hence is long in life. 
FIG. 13 shows a further embodiment of an automatic microfilm retrieval 
system according to the invention. In the present embodiment, provision is 
made of memory writing in keys 90 and memory reading out keys 91 on the 
key board 1. If the index word which has once been retrieval is to be 
stored in a memory, after the key input corresponding to the index word 
has been obtained by depressing the key, the memory writing in key 90 is 
depressed so as to store the index word in the memory. If the index word 
whose contents are stored in the memory is to be retrived, the memory 
reading out key 91 is depressed, as a result, it is possible to retrieve 
the index word whose contents are stored in the memory. 
In the present embodiment, provision is made of four memories and hence 
four memory writing in keys 90 and four memory reading out keys 91 are 
provided on the key board 1. But, it is sufficient to provide at least one 
memory. 
FIG. 14 shows a block diagram of the system shown in FIG. 13. If a memory 
writing in key 90 is depressed, the content in the register 22 is written 
into a memory 92. If the index word of the content in the memory 92 is to 
be retrieved, a memory reading out key 91 is depressed. Then, the content 
in the memory 92 is supplied to the subtracter 25 which functions to 
compare the content in the memory 92 with the content in the memory 24, 
that is, with the barcord which has been read out. The above comparison is 
basically the same as that previous comparison in which the content in the 
register 22 is compared with the content in the memory 24. But, it is 
clear that the operation must be effected under the same condition as the 
OK key is always depressed, that is, the operation must be effected with 
respect to all figures of the memory (with respect to 100 bits in the 
present embodiment). 
In the embodiment shown in FIG. 14, only one memory has been shown for the 
sake of simplifying the drawing, but in the embodiment shown in FIG. 13, 
provision is made of four memories. 
The stored index word may be displayed. In this case, it can easily 
recognize what kind of word is stored in the memory. 
In the present embodiment, the cord representing the index word has been 
stored in the memory, but the spelling of the word before encoding may be 
stored. In addition, that position per se of the index word at which it is 
located may be stored. It is a matter of course that the record on the 
microfilm is not limited to the English-Japanese dictionary. In addition, 
the index words corresponding to the key input obtained by depressing the 
key may be written into the memory 92 in succession so as to be 
automatically stored therein. 
As stated hereinbefore, the present embodiment is capable of storing at 
least one word to be retrieved and retrieving such word by depressing a 
given key only one time, whereby the present embodiment is convenient in 
the case of comparing the meanings of a plurality of words with each 
other. 
FIG. 15 is an enlarged plan view of a further modified embodiment of the 
microfilm shown in FIGS. 2 and 3. 
In the present embodiment, the contents of a dictionary or the like are 
recorded on portions 100-1, 100-2, . . . , with respect to each column, 
provision is made of bar-cord 111-1, 111-2, . . . showing the first and 
last exhibit words of that column. The cord 111-1, for example, shows the 
first and last exhibit words included in the column 100-1. In addition, 
signs 112:1, 112-2, . . . are bar-cords corresponding to each exhibit word 
and a bar-cord showing the phonetic sign of the exhibit word. The bar-cord 
showing the exhibit word is composed of 100 bits, for example. English 
alphabet is composed of 26 letters, so that 1 letter can be represented by 
5 bits. The bar-cord of 100 bits can express the exhibit word composed of 
20 letters. In addition, there are 60 different kinds of the phonetic 
signs, is that if 6 bits represent 1 phonetic sign and the bar-cord 
representing the phonetic sign can represent 120 bits, the bar-cord can 
represent 20 phonetic signs. 
FIG. 16 shows a block diagram of a modified embodiment of the system shown 
in FIG. 11. 
If the bar-cord 111:1, for example, is read out, this read out bar-cord 
111-1 is compared with the input spelling obtained by depressing the key 
so as to judge whether or not the input word obtained by depressing the 
key is present in the column 110-1. If such input word is absent in the 
column 110-1, the next bar-cord 111-2 is read out. On the contrary, if 
such input word is present in the column 110-1. those bar-cords 112-1, 
112-2, . . . showing the spelling of each word in the column 110-1 are 
read out in succession until such bar-cord coincides with the input 
spelling obtained by depressing the key. 
In the present embodiment, if the desired word is retrieved, the phonetic 
sign of the index word retrieved in the memory 24 is directly supplied to 
a sound synthesizer 30 which functions to deliver an output sound signal 
for pronouncing the phonetic sign upon receipt of the input code of the 
phonetic sign in a well known manner. The output from the sound 
synthesizer 30 is supplied through an amplifier 31 to a speaker 70 which 
when driven functions to pronounce the index word. 
If the phonetic sign cords recorded on the microfilm are made large in 
number, it is possible to pronounce a part of the content of the 
manuscript and the present embodiment, therefore, may be applied to a 
cookery book. 
As stated hereinbefore, the present embodiment is capable of recording the 
phonetic sign on the microfilm and hence making the memory small in 
capacity without storing the pronunciation of the index word in a separate 
memory. 
FIG. 17 shows a still further modified embodiment of the microfilm shown in 
FIGS. 2 and 3. FIG. 18 shows an initial position determining mark shown in 
FIG. 18. A microfilm 2 is successively retrieved by a third bar-cord 13-1 
in Y direction. By taking such retrieval operation of the microfilm 2 into 
consideration, an initial position determining mark 116 is formed into a 
region located in front of the third bar-cord 13-1 viewed in the Y 
direction of the microfilm 2 (a region located at left upper in FIG. 17) 
and lying on a center line of the third bar-cord 13-n successively 
arranged in the Y direction, the region being larger than the third 
bar-cord. The region where the initial position determining mark 116 is 
formed has a size such that a position determining mechanism which makes 
use of a conventional mechanical switch, for example, can reliably locate 
the bar-cord reading head 6 (FIG. 1) at any position within this region 
116. 
The present embodiment permits the microfilm 2 to move in a manner such 
that the bar-cord reading head 6 can scan the above mentioned region 116. 
When the reading head 6 arrives at the center line of the third bar-cord 
13-n, the movement of the microfilm 2 is stopped. In this way, it is 
possible to determine the initial position of the microfilm 2 in an 
extremely precise manner. 
In the present embodiment, the initial position determining mark 116 is 
formed by directly printing a given pattern on the microfilm 2. If the 
moving direction (reading direction) caused by an initial direction 
determining key (not shown) is given, the given pattern may composed of a 
moving direction reversing portion 117 located at one end of the X moving 
direction and a pair of movement stop portions 118, 119 located at the 
center part of the mark 116. 
If the initial moving direction is not specified or if the overrun is 
considered, provision is made of an another moving direction reversing 
portion 120 located at a position opposite to the reversing portion 117 
with respect to the pair of movement stop portions 118, 119 located at the 
center part of the mark 116. 
In the present embodiment, the movement direction reversing portions 117, 
120 are formed of thick black-thick black bar lines and the pair of 
movement stop portions 118, 119 located at the center part are formed of 
thick black-thin black bar-lines. A signal produced when the center pair 
of movement stop portions 118, 119 are read out in the order of thin 
black-thick black is disregarded. 
That is, as shown in FIG. 18, if the bar-cord reading head 6 is located at 
a position A of the initial position determining mark 116 under the 
condition that the microfilm 2 is disposed on the stage driving device, at 
first the microfilm 2 is reversed and then stopped at its initial 
position. If the microfilm 2 is located at a position B, the microfilm 2 
is moved in the X direction and stopped at its initial position. If the 
microfilm 2 is located at the optimum position such as a position C, at 
first the microfilm 2 is reversed and then stopped at its initial 
position. 
FIG. 19 is a block diagram of a device for determining an initial position 
of a microfilm according to the invention. A signal from an initial 
position determining key 121 is supplied through a gate 122 to a stage 
driving device 28 for driving the stage 3 (FIG. 1). The stage driving 
device 28 functions to move the stage 3 in a predetermined direction, in 
the present example, X direction. The initial position determining mark 
116 formed on the microfilm 2 is optically read out by a bar-cord reading 
head 6. The signal read out is stored in a memory 24. This signal read out 
from the initial position determining mark 116 and stored in the memory 24 
is supplied to a subtracter 25 and compared with a pattern information 
stored beforehand in a memory 123 exclusively used for reading out to 
generate a signal for discriminating moving direction and stopping 
operation, thereby stopping the movement of the stage 3 at a given initial 
position of the microfilm 2. 
As stated hereinbefore, in the present embodiment, the relative position 
between the stage 3 and the bar-cord reading head 6 is not determined for 
the purpose of determining the initial position of the microfilm 2. On the 
contrary, in the present embodiment, a relatively large initial position 
determining mark 116 formed of a given pattern is directly provided on the 
microfilm 2. In the first place, the microfilm 2 is moved so as to locate 
the reading head 6 within the mark 116. Then, this mark 116 is optically 
read out by the reading head 6 so as to determine the relative position 
between the reading head 6 and the microfilm 2. As a result, the device 
according to the invention can determine the initial position of the 
microfilm 2 in an extremely simple and precise manner. 
In the present embodiment, the initial position determining mark 116 has 
been formed of a pattern for determining the position in the X direction. 
Alternatively, the initial position determining mark 116 may be formed of 
a pattern for determining the position in the Y direction or a pattern for 
determining the position in the X and Y directions. The initial position 
determining mark 116 has been utilized when the microfilm 2 is 
incorporated into the system. Alternatively, the initial position 
determining mark 116 may be utilized after the microfilm has been 
incorporated into the system or before the microfilm 2 is incorporated 
into the system. In addition, a plurality of initial position determining 
marks 116 may be provided on a plurality of positions of the microfilm 2 
and prior to the use of the microfilm 2 the mark 116 nearest to the 
cord-bar reading head 6 is utilized to determine the initial position of 
the microfilm 2. 
In the present embodiment, the initial position determining mark 116 and 
the retrieval bar-cord have been read out by the same bar-cord reading 
head 6. Alternatively, the mark 116 and bar-cord may be read out by 
separate reading heads. 
In addition, the initial position determining mark 116 may be formed of 
various constructions, but must be provided with at least a pattern 
representing a boundary of the regions viewed in the scanning direction. 
FIG. 20 shows contents of a dictionary and bar-cords recorded on a 
microfilm. In the case of reading out bar-cords 131-1, 131-2, 131-3, ... 
and contents of a dictionary 132-1, 132-2, 132-3, ... by a light spot in a 
direction shown by an arrow 133, there occurs no problem when the reading 
out operation is effected along the centers of the bar-cords 131-1, 131-2, 
131-3, ... as shown by an arrow 133. But, if the reading direction is 
slightly deviated from the direction shown by the arrow 133 toward a 
direction shown by an arrow 134, for example, the displacement of the 
reading position from its correct positions becomes gradually increased, 
thereby rendering the reading out operation of the bar-cord 113-3 
impossible. 
FIG. 21 shows construction of the bar-cord 131-1 shown in FIG. 20. In FIG. 
21, reference numeral 140 designates a retrieval bar-cord representing an 
index word and formed of a conventional one. In the present embodiment, in 
addition to this retrieval bar-cord 140, provision is made of a reading 
position correcting mark 141 for detecting and correcting the reading 
positions, a reference mark 142 having a width which is the same as that 
of the center part of the reading position correcting mark 141 and 
correcting the reading position and a starting bar-cord 145 for starting 
correction of the reading position. 
If the bar-cords are read out at their centers as shown by an arrow 144, 
signals shown in FIG. 22A are obtained. If the bar-cords are read out 
along their loci deviated from their centers as shown by arrows 145, 146, 
signals shown in FIGS. 22B, 22C are obtained, respectively. 
As seen from FIG. 21 and FIGS. 22A, 22B and 22C, the pulse width of the 
signals obtained from the reference mark 142 is not changed in response to 
the reading position thereof. But, the pulse width of the signals obtained 
from the reading position correcting mark 141 becomes changed in response 
to the reading position thereof. 
FIG. 23 shows a block diagram of a device for correcting the reading 
position of the microfilm reading device which makes use of the above 
described change in pulse width of the signals obtained from the reading 
position correcting mark 141. 
A microfilm 2 on which are recorded the above described bar-cords and marks 
is read out by a light detector 151 to produce the signals shown in FIGS. 
22A, 22B, 22C. These signals are supplied through a conventional 
change-over device 152 to a retrieval signal processing device 153 which 
functions to compare the input signals with a key board input to produce a 
retrieval output for retrieving the microfilm bar-cords and marks with the 
aid of a suitable driving mechanism. 
If the reading position correction starting bar-cord 143 is read out by the 
light detector 151, the change-over device 152 becomes changed over in 
response to the reading operation of the light detector 151. Then, the 
change-over device 152 functions to supply the next input, that is, the 
signal which has read out the reading position correcting reference mark 
142 to a memory 154. The memory 154 function to convert the input signal 
into a digital signal corresponding to the pulse width of the input signal 
and store the digital signal therein. Subsequently, the change-over device 
152 is changed over again to supply the next arriving signal, that is, the 
signal which has read out the reading position correcting mark 141 to a 
comparator 155. The comparator 155 functions to convert its input signal 
into a digital signal corresponding to the pulse width of the input signal 
and retain the digital signal in a register provided in the comparator 
155. In addition, the comparator 155 functions to compare the value of the 
digital signal with the value which has been stored in the memory 154, 
that is, subtract the former value from the latter value. The above 
mentioned value of the digital signal which has been retained in the 
register provided in the comparator 155 corresponds to the deviation of 
the reading position, so that the result of the subtraction effected in 
the subtractor 155 represents the amount of deviation of the reading 
position. The output from the subtraction 155 is supplied to a light 
detector driving mechanism 156 which becomes operated in response to the 
value of the result of subtraction effected in the subtractor 155 to move 
the light detector 151, thereby bringing the light detector 151 into 
alignment with the center 144 of the bar-cords. 
At the end of the above mentioned operations, the change-over device 152 is 
again changed over to supply the next reading out signal, that is, the 
signal corresponding to the retrieval bar-cord 140 to the retrieval signal 
processing device 153 so as to effect the retrieval operation. 
In the present embodiment, provision has been made of the reference mark 
152. If the reference mark 152 is absent and the reading speed is 
different, even when the same position of the reading position correcting 
mark 141 is read out, the signals to be obtained becomes different from 
each other. As a result, it is impossible to detect which position has 
been read out by the light detector 151. In the present embodiment, 
provision is made of the reference mark 142 and the signal which has read 
out the reference mark 142 is compared with the signal which has read out 
the position detecting mark 141. If these two marks are read out at the 
same speed, even when the reading speed is different, it is possible to 
detect the reading position. As a result, if the reading speed can 
correctly be defined the reference mark 142 may be omitted. 
In the present embodiment, provision has been made of one of the reading 
position correcting marks 141, 142 for every one retrieval word bar-cord 
140. Alternatively, provision may be made of a plurality of reading 
position detecting marks 141, 142 or may be interposed between the 
bar-cords, for example, between the bar-cord 131-1 and the bar-cord 131-2 
shown in FIG. 20 or one of the reading position correcting marks 141, 142 
may be provided for a plurality of retrieval bar-cords 140. 
In the present invention, the position of the light detector 151 has been 
moved for the purpose of correcting the reading position. Alternatively, 
the microfilm 2 may be moved. In addition, a light deflector may be 
inserted into a light receiving path of the light detector 151 and the 
light deflector may be oscillated so as to correct the reading position. 
FIG. 24 shows another embodiment of the reading position correcting mark 
shown in FIG. 21. The reading position correcting mark shown in FIG. 24 is 
of step-shaped one instead of frustum-shaped one shown in FIG. 21. 
A reading position correcting mark 30 shown in FIG. 25 is of rectangular 
one inclined to the center line 163. In the present embodiment, the 
reading position is detected by difference in reading timing T with 
respect to the reference mark 161. 
FIG. 26A shows signals obtained when the bar-cords are read out at their 
locus deviated from their center as shown by an arrow 162, FIG. 26B shows 
signals obtained when the bar-cords are read out at thin center as shown 
by an arrow 163 and FIG. 26C shows signals obtained when the bar-cords are 
read out at their locus deviated from their center as shown by an arrow 
164. 
In the embodiments shown in FIGS. 21 and 25, the reading out operation has 
been effected in one direction only. If the starting cord 143 (FIG. 21) is 
arranged at both sides of the reading position correcting mark 141, the 
reading out operation may be effected in two directions. 
In addition, in the present embodiment, the cord or mark has been optically 
recorded on the microfilm. As the above mentioned minute cord reading 
device, use may be made of a magnetic device or the like for reading out 
records. In this case, the deviation of the reading position may be 
detected by changing the strength of magnetization in a direction 
perpendicular to the reading direction instead of changing the width and 
the like of the cord. In the present embodiment, the reading position 
correcting mark 141 has been provided independently of the retrieval 
bar-cord 140, but the retrieval bar-cord 140 may also be used as the 
reading position correcting mark 141.