Microfiche inspection apparatus

A microfiche viewer structured for examining new microfiche film. The film is typically still in roll form as it comes from the microfiche camera. Plural magnifications of the microfiche image are selectively available; one, to reproduce a whole fiche upon the viewing screen for general observation of photographic quality, the other, to reproduce perhaps four frames of a whole microfiche for detailed observation of quality. The apparatus is structured for convenience in viewing. The different magnifications are obtained by selectively interposing objective lenses of different focal length in the light path adjacent to the microfiche film on the side opposite to that occupied by a light source. Motor driven film transport means are provided atop the apparatus proper.

BACKGROUND OF THE INVENTION 
This invention pertains to optical viewers for microfiche. 
Microfiche viewers of single frames are known to the art. Except for making 
a hard copy from microfiche, such a viewer is required to present a 
transient optical image at substantially the size of the original document 
to one who wishes to read the information involved. 
In simple terms, microfiche viewers may be considered as a "magic lantern" 
slide projector of antiquity with the addition of a built-in screen. 
However, today sophisticated microfiche film-positioning means are required 
to successively present single frames from the microfiche. An over-view of 
the whole fiche is not desired. 
The art has made provision for infrequently altering the magnification of 
viewers. This has been for the purpose of properly reproducing fiche that 
were originally optically reduced by specific ratios, such as 24 or 48. 
Alteration has usually required removing one objective lens and replacing 
it with another of different focal length. 
SUMMARY OF THE INVENTION 
Microfiche inspection apparatus requires means to rapidly and 
all-conveniently accomplish an in-focus change of the magnification of the 
reproduction from a low value that allows cursory inspection of the whole 
microfiche to a high value for detailed inspection of one or a very few 
frames to detect small imperfections. Also, means to rapidly and 
conveniently transport the film from one end of the roll to the other are 
desirable. Such means are provided. 
A lever system for each objective lens that is simultaneously actuated by a 
single manual control conveniently mounted on the side or the front of the 
over-all enclosure is provided. 
Auxiliary condensing lenses to provide full-field illumination of a whole 
fiche for the reproduction thereof, or of only a very few frames for the 
reproduction thereof may also preferably be linked to the same lever 
system. 
A pair of electric motors provide transport for the reel of fiche film from 
one end to the other. Manual or automatic control is available. 
A transparent platen that automatically opens whenever the film is moved is 
also provided.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIG. 1 numeral 1 indicates an enclosure which houses the major portion 
of the optical system of the device of this invention. It is preferably 
light-tight. A viewing screen 2 is inclined at an angle to the vertical 
for convenient viewing by an operator at the front of the enclosure. The 
screen is translucent, since the image is impressed upon it from the rear. 
The screen may have a gray tone to provide the best contrast in the image 
in the presence of ambient light. One suitable material for the screen is 
glass, frosted, and having optically directional characteristics to direct 
the light forward to the operator. A thickness of 4 mm is appropriate. The 
screen may be any size, but a height of 56 cm and a width of 84 cm is 
typical. 
A lower support 3 positions enclosure 1 at a height where an operator 
standing or seated upon a stool is positioned to conveniently view screen 
2. 
A lamphouse 4 centrally surmounts enclosure 1. At the top it contains a 
high intensity light source, typically incandescent, while below it 
contains a selectable plurality of condensing lenses. 
The microfiche film 5 to be examined is positioned directly beneath the 
lamphouse. The film may be a single microfiche, having the usual size of 
15 cm wide by 10.5 cm high, but more frequently it is a whole roll of 
microfiches. These are usually exposed in a camera and processed on a 
strip 15 cm wide by 120 meters maximum length. 
An upper transparent platen 6 is disposed above film 5 and can be raised, 
while lower transparent platen 16 is fixed. See FIGS. 2 and 6. 
When the microfiche are in roll form the film is typically wound on a reel 
7, which is mounted on a spindle 8. The latter may also be the shaft of a 
controllable slow speed motor 9. Alternately, a small d.c. motor having a 
pinion and a separate shaft for spindle 8 with a gear and a toothed belt 
between the two may be employed. A spped reduction ratio of ten to one is 
suitable. 
A take-up reel 10, upon shaft 11 of motor 12 or the alternate structure 
mentioned, is disposed on the opposite side of lamphouse 4 from the prior 
assembly in a complementary structure for reeling the roll of microfiche 
film after it has been optically inspected. Both motors are reversible, so 
any desired back-and-forth translation of the microfiche film is possible. 
As will be later detailed, a change in objective lenses accomplishes the 
change in magnification for alternate inspection purposes as previously 
mentioned. This is accomplished by the operator swinging handle 14 about 
90.degree. in one embodiment. Alternately, an equivalent linkage that is 
activated by a knob that is mounted on the front control panel 15 may be 
used. 
In any event, a separate image focus knob 17 is mounted on the right side 
of the control panel. 
Frame 18, at the rear of the upper part of enclosure 1 supports elements 
within lamphouse 4. 
In FIG. 2 the path of microfiche film 5 is shown as chiefly defined by 
reels 7 and 10, rollers 20, upper platen 6, and lower platen 16. All of 
these elements are mounted on a table 21, which in turn is supported by a 
plurality of ball bearings also bearing upon the top surface of enclosure 
1. By manual manipulation this allows any frame of the microfiche to be 
positioned in the optical path for reproduction on screen 2. The motion of 
the table is horizontally, transverse of the optical axis. 
An electro-actuator 22 provides the mechanical force for raising upper 
platen 6 when film 5 is translated; thereby to prevent scratching when the 
film is in motion. When the film is stationary the two transparent platens 
are together, to provide a flat microfiche film at a fixed focal position 
along the optical path. Constantly in-focus reproduction of the microfiche 
image regardless of the magnification utilized and regardless of 
subsidiary factors is highly desirable and the structure of this invention 
contributes to this. 
In FIG. 2 long focal length lens 24 is shown in the optical path. This path 
originates with source of light 25, passes through condensing lens system 
19, 62, 38, film 5, objective lens 24, small inclined mirror 25', large 
inclined mirror 26, and screen 2. The latter two elements are to be seen 
in FIG. 1. The axis of the optical path is shown by dashed line 27 in FIG. 
2. Preliminary mirror 13 deflects the illumination 90.degree.. 
An important part of the inspection apparatus is a precision means for 
selectively entering lenses of different focal length into the optical 
path. Swinging handle 14 rotates shaft 30 when the handle is moved in an 
arc. About 90.degree. rotation is typical. Gear 31 is fastened to shaft 
30, the latter being journaled in "U" mounting 32. Pinion 33 meshes with 
gear 31 a provides about a two-to-one step-up in speed of rotation. Pinion 
33 is fastened upon shaft 34, which is also journaled in mounting 32. 
Shaft 34 turns 180.degree. and "detents" into position because clamps 29 & 
29'are spring loaded by tension spring 51 to clamp onto the flattened 
portion of the shaft each time it rotates 180.degree.. 
Arm 35 is rigidly attached to shaft 34. In FIG. 3 it is shown at top dead 
center, which is one position where it stops because of the clamping 
action on shaft 34. It also stops at bottom dead center. 
The mass of the lenses 24 and 27 is slowed-down at the ends of the travel 
involved in changing the magnification of the apparatus by the simple 
harmonic motion of arm 35. The elastic bounce-back of the mass of the 
lenses does not rotate shaft 34 flats out of clamp 29 & 29' because of 
this dead center configuration. The same situation obtains 180.degree. 
removed when arm 35 is at bottom dead center. 
Arm 35 is connected to and actuates rod 36. Rod 36 has stud 37 centrally 
located along the length thereof. This allows adjustment of the length of 
the rod upon disconnection of one end thereof and rotation of one part 
with respect to the other. Such adjustment insures that the objective 
lenses shall be accurately transversely centered upon optical axis 27. 
Rod 36 is pivotally attached to arm 38, which in turn is attached to shaft 
39. Arm 40 is also attached to shaft 39 at the lower extremity thereof and 
carries long focal-length lens 24 at its cantilevered extremity. Various 
optical parameters may be selected for embodiments of this invention. 
However, a magnification of 44 times is a desirable parameter when lens 24 
is employed. This is accomplished by employing a lens having a focal 
length of the order of 200 mm and an aperture of 5.6, located 
approximately 20 cm below film 5. 
Lens 24 is focused from the front panel by turning knob 17. This knob is 
attached to rod 42, the forward portion of which is threaded and revolves 
in internal threads in front panel 15. Rod 42 is thus translated axially 
as well as being rotated when knob 17 is turned. Rod 42 is terminated at 
arm 43, where incremental swinging of that arm occurs upon the rotation of 
rod 42. This results in axial translation of rod 44, which is provided 
with length adjustment by telescoping under the control of fasteners 45. 
Lever 46 is provided with a fulcrum intermediate the attachment of rod 44 
thereto, while the other end of lever 46 translates shaft 39 vertically. 
This translation accordingly translated lens 24 along optical path 27 and 
thus alters the focus of the image of the microfiche upon screen 2. 
In-focus adjustment is thus possible. 
Wide-angle lens 47 is positioned vertically within approximately 15 mm of 
film 5. The lens is provided with a floating spring mount. Springs 48 urge 
the lens mount upward against lower platen 16. This insures in-focus 
performance of this lens without the need for adjustment by the operator. 
The lens may have a focal length of 35 mm. 
A black planar light baffle 49 is attached to the structure of lens 47 and 
moves horizontally with it. The baffle prevents spurious light from the 
initial part of the optical system from impinging upon mirror 25' and 
thereby causing spurious illumination and loss of contrast in the 
reproduced image on screen 2. 
Shaft 39 and related elements are journaled or supported by frame 50, which 
may be a casting. 
For the high magnification mode of operation greater convergence of the 
light beam by the condensing lens system is desirable. Two additional 
condensing lenses are thus inserted in the condensing part of the optical 
system. 
This is mechanically accomplished by arm 52, which is attached to shaft 55. 
Upon an upward prolongation of this shaft a pair of horizontal arms 53 and 
54 carry additional condensing lenses for insertion into the optical path 
when lens 47 is used. An additional heat-absorbing glass (not shown), may 
also be inserted directly in front of illuminating lamp 25. 
As shown in FIG. 4, arm 53 and its prolongation 59 are in line when lens 19 
is in optical-use position. It is not necessary that shaft 55 stop in a 
precise position because the position of lens 19 is not sensitive to small 
changes in the angular relationship of arms 53 and 59. 
Although this angular relationship is not important, the combined lengths 
of arms 53 and 59 is important. Accordingly, adjusting stud 67 is provided 
at the center of arm 59. This is the same structure as adjusting stud 37 
in prior arm 36. 
The positioning of the horizontally disposed additional condensing lens 62 
is shown in elevation in FIG. 5. Pin 60 is loose in its hole. The weight 
of lens 62 causes bracket 63 to pivot about stud 64 under the influence of 
gravity until lens-carrying bracket 63 comes to rest against adjustable 
stop 65, which is supported by the main frame of the device. Again, the 
rotational position at which shaft 55 comes to rest is not critical. Arm 
61 is the prolongation of arm 54. 
The previously mentioned platen 6, 16, is detailed in FIG. 6. 
The top transparent glass member 6 lifts vertically upward without rocking 
by virtue of the structure provided. Proper optical design does not 
provide a large vertical space for this lifting, and so a straight-up 
movement provides the largest platen-open space, with the smallest 
probability of scratching the microfiche film when it is translated from 
one fiche to the next, or when it is translated a distance occupied by 
many fiches to exhibit a particular one. 
The rectilinear motion achieved also prevents abrasion of the film when the 
upper member is lowered down upon the film to perform the 
film-straightening platen function. 
Short arm 70 in FIG. 6 lifts the rear of the upper platen 6 and long arm 71 
lifts the front of the upper platen. The arms are both raised by roller 
72. Normally, the structure shown in FIG. 6 is duplicated directly behind 
it, so that the upper platen is lifted at its four corners. Roller 72 is 
raised when arm 73 rotates, as shown by arrow 74. The pivots for these 
arms, i.e., stationary fulcrum points 75 and 76, are at a distance from 
roller 72 in each case the same fraction as the distances from the roller 
to the lifting points 77 and 78; thus the lifting points each move upward 
the same amount. 
Upon the manipulation of suitable push-buttons that are provided electrical 
control 56 exercises forward and reverse rotational control of motors 9 
and 12. Appropriate reeling of film 5 can thus be accomplished. Typically, 
this is arranged with a forward rotation of one motor with a reverse 
rotation on the other motor, with joint control of the motors to insure 
even translation of the film. 
Similarly, a connection from electrical control 56 to actuator 22 energizes 
the same when either or both of the motors are energized, to lift platen 
6. The reverse is also true. Thus, possible scratching of the film is 
automatically prevented and the microfiche is automatically clamped by the 
platen when the film is stationary, thus being is focus.