DE2738658A1 - COMPACT OPTICAL VIEWING DEVICE FOR INFORMATION STORED IN MICROFORM - Google Patents

Description

The invention relates to a device for projection and for viewing information stored in microform. The invention particularly relates to a Compact viewing device in which micro images projected from a microfiche or microfilm be reflected several times and directed onto a screen.

Some embodiments of the present invention are an improvement of the UB -PS 3 94-1 467 better known. Contraption; the content of this patent specification is hereby incorporated into the present Registration made. As set out in this US-ratentschrift, is in a microfiche reader a projected cone of light folded by successively striking a number of reflective surfaces is reflected until it finally hits the viewing screen falls. The number of reflective surfaces will be different from the outside! '' Laugh formed of a solid body. This solid body has the i'orm of a trapezoid. A dar reflective Surfaces of the trapezoid have a dual function. Once we form a reflective surface and in addition, it lets light, which has been reflected again, pass through and for image generation falling the screen. This is done by choosing certain angles of the reflective surfaces achieves that the light rays initially fall on this two-function surface at an angle, which is larger than a certain critical angle for total internal reflection. This critical angle depends in turn on the refractive index of the material from which the trapezoid is made. This well-known

809811/0723

- Io -

- Io -

Device uses a Fresnel lens, which for the operation of the device is not important, but is only used to produce a brighter and to generate a more evenly illuminated image, especially at the edges.

According to the present invention, a similar one becomes The effect is achieved by folding a cone of light several times before it hits a screen. According to the present invention, however, there is no solid body designed as a trapezoid and also no other body made of translucent material is required. Instead, one also becomes two Functional area defined by a series of prisms which form a prism sheet. The prism sheet can perform the two functions described and in addition to focusing the serve the final image on the screen.

An advantage of the present invention over the known device is that it allows manufacturing of devices allowed, which have much less weight and can also be manufactured more cheaply are. Instead of a relatively heavy and expensive, massive plastic block (the trapezoid) reflective surfaces used, which are formed by flat mirrors in the form of sheets or plates which can be manufactured cheaply and arranged relative to one another. In addition, requires the use of a solid block increases the throwing distance of the light cone for one of the same size Viewing area. When using a solid block of transparent material with a refractive index η is the throwing distance η times the straight

809811/0723 ¹¹

Invention required throw. For example, if the device according to said US Pat. No. 3,941,467 using a trapezoid made of polymethyl methacrylate (n ■ 1.5) a throw of about 22.9 cm (9 inches), the throwing distance is for one according to the invention Device only about 15.24 cm (6 inches). Due to the smaller throwing distance, it can be the same Screen size the device can be made more compact.

Further advantages and features of the invention emerge from the claims in connection with the following description various embodiments and the drawing. In the latter show:

Figure 1 is a schematic view of a simple arrangement of folding mirrors,

Figure 2 is a partially schematic representation of the device of Figure 1 in the folded state,

Figure 3 is a perspective view of the viewing device of Figures 1 and 2 in the open position,

FIG. 4 shows a view similar to FIG. 1 of a modified embodiment,

FIG. 5 shows a view of a device according to US Pat. No. 3,941,467,

FIG. 6 shows a view similar to FIG. 1 of a further embodiment which has a prism sheet contains, which fulfills two functions,

- 12 -

809811/0723

FIG. 7 an enlarged view of the section marked in FIG.

FIG. 8 a modification of a prism sheet,

FIG. 9a is a view similar to FIG. 7, which illustrates the use of two prism blades, if a mirror is placed immediately behind the first prism sheet in the optical path is,

Figure 9b is a view similar to Figure 9a showing the use of a second pair of prism blades illustrates

Figure Io is a view similar to Figure 2, which shows a complete viewing device constructed according to the principles shown in FIG is,

Figure 11 is a partially schematic sectional view along the line 11-11 of Figure Io, two Ilicro-image projection lenses over two parallel tracks of a film strip from a Philips cassette are arranged

Figure 12 is a partially schematic view similar to the figure showing a viewing device shows which both with a Fhilips cassette as well as a standard microfiche of 16 cm (4 inches) by 12.54 cm (6 inches),

- 13 -

80981 1/0723

FIG. 13 is a partially schematic view of a further embodiment of the invention,

FIG. 14 shows the embodiment of FIG. 13 in the open Position,

FIG. 15 shows a further embodiment of the invention,

Figure 16 shows the embodiment of Figure 15 in a folded Position,

FIG. 17 shows a viewing device of FIG. 15, however with a different folding of the screen and a mirror,

Figure 18 shows a further embodiment of the invention and

FIG. 19 shows a view of the embodiment of FIG. 18, but with an additional mirror and a foldable one Umbrella.

In the figure 1 is a device for viewing information stored in microform, for example on a Microfiche, shown schematically. The reference numeral denotes a projection lens which is a micro image from a microfiche or other photographic Projected a reduction, the microfiche itself not being shown. The principal ray of the lens or the cone of light projected from the lens system has the reference numeral 12 and falls on a first mirror 14-. The main beam then falls on a second mirror 16, then on a third mirror 18 and finally to Image generation and viewing on the screen 2o. Pivoting or rotating members 22 and 24 are on the last mirror

- ΛΗ- -

809811/0723

and attached to the screen 2o, as indicated in the drawing. As can be seen in Figure 2, the device folded by first the screen 2o around the pivot point 24 and then around the Pivot point 22 is rotated. The reference numeral 26 generally designates the displayed elements of the Viewing device. Figure 3 is a perspective view of the general shape and proportion of the viewing device when it is in its deployed working or viewing position.

Figure 4 shows another embodiment which that of Figures 1 to 3 is similar, but in which the viewing screen before projecting The cone of light is located, the main axis of which is identified by the reference numeral 12. One recognizes a certain Relationship with the embodiments of the figures 1 to 4 of a foldable viewing device according to US-IS 3 667 839 by Artaud. In this viewer is a foldable arrangement is shown in which light is projected onto two reflective surfaces falls, and then forms an image on a viewing screen. The device of Figures 1 to 4 of this However, registration has the advantage of an additional reflective surface, whereby one receives greater magnification. In addition, the species the folding to make the device more compact.

In FIG. 5, 3o generally designates the most important optical elements of the device according to the aforementioned US Pat. No. 3,941,467 to kapany. The reference number 31 denotes a solid or massive block transparent haterial through which a cone of light

809811/0723 " ^ ~

is projected, the vertex of which bears the reference numeral 32. The Lichtkregel represents light, which comes from a micro image. The main ray 33 strikes a first reflective surface 3 ^. From there it falls under a greater than that critical angle with respect to the normal to the surface 35 of the solid body and becomes from there reflected to the reflective surface 37. Coming from here, the light passes vertically through the Surface 35 can be viewed from. It will pointed to the elongated, dashed lines in the region of the vertex 32 of the light cone. These elongated lines illustrate the refractive effect to which light is subject when it enters the transparent material 31 from the air.

In Figures 6 and 7, a compact optical viewing device is shown, which also has a Has surface that has two functions, but which both in terms of size is also more advantageous and superior in terms of cost. The main ray can be seen in FIG 12 of the projected light cone, which carries a micro-image to be viewed. The beam hits first on the reflective surface and then on a prism sheet 44. He is then on the surface of the prism sheet is totally reflected inside, as in the case of the surface 35 of the device by Kapany, and hits then onto the second mirror 16. From there it exits perpendicular to the prism sheet and falls onto the Screen 46. As shown in FIG. 6, the light coming from mirror 16 passes through in a straight line through prism 44, however, the reader will understand that

809811/0723 -I6-

(ί is the light coming from the mirror 16 is refracted, as shown in Figure 7 when it passes through the prism sheet.

In Figure 7 is an enlarged section of the screen 4-6 and the prism sheet 44 of FIG. There is an air gap 48 between these two. The prism sheet 44 is more protruding by a plurality Hippen defines which are on a surface of the leaf and which, like the leaf itself, are are transparent. Each rib has two surfaces which are generally flat in cross-section, though one or both surfaces of each of these ribs can be curved. These protruding ribs are in the entire prism sheet shown straight or flat and parallel to each other. However, the above can also be used Ribs are used which have an elliptical contour, the axis of the light cone a of the two focal points of the enclosed ellipses.

Another form of prismatic structure is shown in FIG. The prism sheet 44 must not be confused with a Fresnel lens, with which it only has external similarities. The individual ribs which form the prism sheet have an elliptical contour, although they are similar in cross section to the embodiment described above. The ribs have the reference numeral 5o, while the reference numeral 52 denotes the point of intersection of the main ray 12 of the light cone with the prism sheet. It can be seen that point 52 is a focal point of the nested elliptical ribs.

809811/0723

In Figures 9a and 9b there are two and four prism sheets, respectively shown. If only a single prism sheet is used in the viewing device is, as for example in Figures 6 and 7 "is the Viewing screen placed adjacent to the flat surface of the bill of sale. If, however Light that has passed through the first prism sheet and is to be reflected afterwards must a second prism sheet may be provided so that the direction of the light rays is not changed. If however, the thickness of the prism sheet is too large, the image on the fluoroscopic screen will be due to the intersection of the light rays shown in Fig. 9a is strongly distorted. This distortion will however Negligibly small for the eye if the number of prisms is large, e.g. if 2oo prisms per 2.54 cm (1 inch) are provided. The distortion produced is not resolved by the human eye.

To enhance the image on the screen, a second pair of prism blades can be placed next to it the first prism sheets and be provided in alignment with them, thereby causing the intersection of the light beams is canceled again, as shown in Figure 9b. Εε it goes without saying that with all described Embodiments in which only a pair of prism sheets is provided, the optical Beam path improved by adding an additional pair of prism blades, as in Figure 9b can be.

In FIG. 9a, a prism sheet 54 has surfaces 56 and 58 of a typical rib. An air gap 6o

- 13 -

809811/0723

is provided between the flat surfaces of the prism sheet 54 and a second prism sheet 62. Surfaces 64 and 66 of a typical rib of fin sheet 62 correspond to surfaces 56 and 58. You can now see that the surface 58 is parallel to surface 64 while surface 56 is parallel to surface 66. Furthermore For example, either or both of the homologous surfaces 58 and 64 may be curved to effectively form a Form lens. Similarly, either or both of the homologous surfaces 56 and 66 can also be curved to similarly define a lens.

Figures Io and 11 show a further embodiment in which two projection lenses are used will. In FIG. 11, 12 and 12 'denote the main axes of two projected cones of light, from each corresponding to a corresponding part of 2 parallel tracks of optical film of a Philips cassette is equivalent to. The viewing device bears the reference numeral 28 ', while 26 again denotes the auxiliary devices of a typical viewing device.

FIG. 12 shows a further embodiment which is similar to the embodiments described above but which is designed as a compact viewing device incorporating both a microfiche, e.g. in the standard size of 16 cm (4 inches) by 15 »24 cm (6 inches), as well as an alternative Philips cassette. The microfiche 7o uses a projection lens lo, while the cassette 72 uses a

80981 1/0723 - 19 -

Projection lens Io 'is used. You can see that the Mirror 11 is pivoted out of the optical path when the cassette 72 is used. To this Either the microfiche or the cassette can be used for projection.

In FIGS. 13 and 14 there is yet another modification of a compact viewing device shown. A first mirror 76 receives a cone of light, which is from a cassette or a is projected onto other carriers of reduced-scale information. At 78 there is a second Mirror and 8o is a third mirror. As before, a prism sheet 44 is again provided, and a viewing screen bears the reference numeral 46. The principal ray again bears the reference numeral 12. This device works similarly to the previously described embodiments. In this embodiment, however, the reflective surfaces are, in particular the first and second surfaces arranged substantially parallel to one another. As before light falls on the prism sheet 44 at an angle greater than the critical or critical angle is and is reflected, while light rays, which are essentially perpendicular to the prism sheet, pass through and are visible on the screen 46.

The embodiment of FIG. 14 differs from that of FIG. 13 in that it has pivot points 86 and 88 and an additional mirror 82 which is coupled to the screen 84. When the screen is not in use, it is pivoted clockwise about pivot point 88,

809811/0723 _ _2o .

- 2ο -

it lies parallel to the mirror 82, and then become these two elements are pivoted about the pivot point 36 in a clockwise direction. Furthermore, a pair is parallel and spaced apart prism sheets 54 and 62 are provided, their effect and The arrangement is as described with reference to FIG.

A further embodiment is shown on the basis of FIGS. 15 and 16 described. A first, second and third mirror have the reference numerals 9o, 92 and 94. The viewing screen bears the reference number 96, while the main beam of the light cone, which comes in from a cassette or from an information store is projected, again bears the reference numeral 12. The screen has a pivot point 98, at which it is connected to the upper edge of the mirror 94, while the lower edge of the mirror has a pivot point loo, which is located on the left section of the mirror 92 in FIG. One transparent pane, e.g. a glass plate, has the reference symbol Io2. The operation of this device goes from FIG. 15. To fold the device up when not in use for viewing the screen 96 is rotated clockwise so far

rotated axis 98 until it is parallel to mirror 94. These two elements then become rotated counterclockwise about a pivot point loo until they are parallel to the mirror 92. the Glass plate Io2 serves to protect the interior of the device when it is folded, cf. Figure 16.

- 21 -

809811/0723

Figure 17 shows a similar construction, the main difference being in the type of folding to the Storage and the use of two prism leaves with a dual function. A mirror 93 is adjacent to the last reflective surface and a mirror 94 forms the latter reflective surface. The screen again bears the reference numeral 96 and the main beam bears again the reference numeral 12. In order to fold the device of FIG. 17, the mirror 94- so becomes to the right moves that its lower portion slides on the top of the viewer, the screen 96 is pivoted clockwise about the axis loo.

FIG. 18 shows a further embodiment of a compact viewing device according to the invention shown. A first reflective surface is labeled Ho (with any small Mirrors near the apex of the projected cone of light are neglected), a second reflective Surface bears the reference number 112, while 44 again denotes a prism sheet, which is associated with a spaced screen 46. There is a slot 113 for receiving one Microfiches are provided, but it should be understood that the elements 26 can be modified so that Instead of a hikrofiche, a Philips cassette can be used, which contains the optical information contains. One of the stored micro information projected cone of light contains a principal ray 12 and hits surfaces Ho and 112, like it is shown. A reflective surface 114 is as in the drawing, arranged so that it extends to the top left to the left end of the frismatic sheet

809811/0723 -22-

extends. The dual function of the prism sheet 44 is the same as that described above.

FIG. 19 shows a modification of the device 18, this modification being an additional mirror 115 and a screen 116 differentiates which is articulated on the upper side of the mirror 115 via a pivot point 12o, the Mirror 115 in turn has a lower pivot point 122. The optical effect of this embodiment of Figure 19 is evident. To fold this device, the screen 116 is about the axis 12o im Rotated clockwise until it is parallel to mirror 115, and then the two Elements pivoted about pivot point 122 clockwise towards the top of the device.

The prism sheets, e.g. the prism sheets 44 of Figure 7 and the prism sheets 5 ^ - »62 of Figure 9a, which have been described in connection with most of the exemplary embodiments can be shaped similarly as it relates to Figures Io and 11 originally filed in the United States on August 13, 1976 Patent application Ser.No. 714,225 entitled "Light Channeling Devices" which is hereby made the subject of the present application. A batch of in general Rectangular metal disks will be distorted or bent so that the disks are relative to each other slip. A set of edges of these disks thus assume a staggered arrangement, as shown in FIG of the said application is shown, with the exception that the edges are not biased as is is indicated by the reference numeral 72, but that

809811/0723 - 23 -

rather, they are rectangular, as in the figure Io is shown. In addition, these edges are not as far apart as shown in FIG instead, they have been offset by an amount, by an edge cross-section to produce, which is the same as that of the prism sheet 44 of Figure 7 of this application. the The edges of the panes are polished into mirrors. The resulting disk array can now be saved as either Casting mold or used as a master for electro-forming. The mirror-polished ends of the disc result the desired optically flat surfaces of the individual ribs of the prism sheet, such as the flat surfaces 56 and 58 of the prism sheet 54 of FIG. 9a this registration.

809811/0723

Claims (1)

EXPECTATIONS 1. Optical projector for projecting a cone of light from an illuminated micro-image, marked through a variety of reflective surfaces, which fold the cone of light and one surface of which reflects light, which under one Angle strikes them that is greater than the critical or critical angle, but which light can pass through leaves, which is noticeable at an angle that is smaller than the critical or limit angle, characterized in that said reflective surface consists of a prism sheet (44) exists, next to which, but parallel to this, a screen (46) is arranged at a distance. 809811/0723 - 2 - POSTAL CHECK ACCOUNT MUNICH 196858-807 DRESDNER BANK MUNICH, ACCOUNT NUMBER 7 7O6OO5 ORIGINAL INSPECTED 2. irojector according to claim 1, characterized in that that the prisms form a surface of a transparent sheet (44). 3. Optical projector for projecting a cone of light from an illuminated micro-image goes out, with a first reflective surface, which a projected light cone under one of 9o ° different angle intersects, with respect to the axis of the cone, with a second reflective one Surface which is arranged at an acute angle to the first reflective surface, with a third reflective surface, which make an obtuse angle with the first reflective Surface, with the second reflective surface generally parallel to the sides of the projected light cone and all light coming from the first reflective surface reflects, which is noticeable at a larger angle than the critical angle, but which allows light to pass through, which is smaller than the critical angle, characterized in that the second reflective surface is formed by a series of prisms (44), the apex surface of which is generally the third reflective Surface (16) faces and its bases parallel to the second reflective surface are. 4. A projector according to claim 3 »characterized by a second set of prisms (62 ^N i which are identical to the first set of prisms (54), the vertices of the elements of the second prism set (62) being opposite to the direction of the vertices 809811/0723 of the first set of prisms (54 ·) are arranged and the first set of prisms and the second set of prisms each form a plane which is parallel to each other are. 5. Projector according to claim 3 or 4, characterized in that that the optical path of a cone of light falling on the reflective surface, passes through air everywhere except during its passage through the prisms. 6. Projector according to claim 1 or 2, characterized in that the optical path of the light cone, which hits the reflective surface runs through air everywhere except during the Passage through the prisms. 7. Optical element for fulfilling two functions, characterized by a large number of prisms on a surface of a sheet, the prisms and the sheet being transparent. 8. Optical element according to claim 7, characterized in that that the prisms are straight and parallel to each other. 9 «Optical element according to claim 7 or 8, characterized characterized in that the sides of the prisms are isosceles in cross-section. lo. Optical element according to one of Claims 7 to 9 » characterized in that the sides of the prisms are arranged at an angle of 90 ° to one another are. 809811/0723 .4. 11. A projector according to claim 4, characterized by a third set (62) and a fourth set (54) of Prisms which are identical to the first set of prisms (54) and the second set of prisms (72), wherein the third and fourth sets are arranged relative to one another in the same way as the first set relative to the second sentence and where the third and the fourth set of prisms each define a plane and the planes of the first, the second, the third and fourth set of prisms are arranged parallel to each other. 12. Optical element according to claim 7 * characterized in that that the prisms have an elliptical contour when viewed from above, with the elliptical prisms (5o) are nested in one another and have a common focal point. 13. Optical projector for projecting a cone of light from an illuminated micro-image, characterized in that that a pair of reflective surfaces is provided which intersect the light cone and reflect, the point of intersection of the center (12) of the light cone with the first reflecting area further away from the vertex of the light cone than the intersection of the center of the light cone with the second reflective surface is that a third reflective surface is provided is, which is pivotably mounted at its one edge about an axis which is perpendicular to the axis of the light cone is that the third reflective surface carries a screen (46) on the opposite Edge of the third reflective surface is hinged and in a position parallel and adjacent the third reflective surface can be pivoted, 80981 1/0723 lind that the axes of the two pivot points are parallel are to each other. 14. Optical projector for projecting a cone of light coming from an illuminated micro-image, thereby characterized in that a first mirror and a second mirror are substantially parallel to one another are arranged that the second mirror with an edge next to the edge of a third mirror is arranged that the first and the third mirror form an obtuse angle with each other that a Prism sheet is arranged in the plane of the second mirror and next to this that the prism sheet opposite the third mirror, and that a viewing screen is parallel next to that Prism sheet is arranged at a distance from this. 15- Optical projector to project one of one illuminated micro image coming light cone, characterized in that a first and a second Mirrors are arranged essentially parallel to each other that the first mirror with an edge is arranged next to the edge of a third mirror that the first and the third mirror Form an obtuse angle with each other that a first prism sheet in the plane of the second mirror and is arranged next to this that the prism sheet is arranged opposite the third mirror that a second prism sheet next to and parallel to the first prism sheet, but at a distance from it is arranged that a fourth mirror around its one edge about an axis perpendicular to the axis of the Light cone is arranged pivotably and on 809811/0723 its opposite edge pivotally carries a screen which is in a position parallel to the fourth mirror can be pivoted up to this, and that the axes of the two pivot points are parallel are to each other. 16. Optical projector to project one of one illuminated micro image coming light cone, characterized in that a first and a second Mirrors are arranged essentially parallel to one another, that a third mirror is essentially perpendicular to the first two mirrors is arranged that a screen at an angle to the third Mirror is arranged that the screen is hinged to an edge of the third mirror, and that the third mirror is hinged to either the first or the second mirror. 17. Optical projector to project one of one illuminated micro image coming light cone, characterized in that a first and a second mirror are arranged substantially perpendicular to each other that a prism sheet is generally perpendicular to the second mirror is arranged that a third mirror at an acute angle to the plane of the Prism sheet is arranged that the plane of the third mirror essentially through the intersection the first two mirrors runs, and that a screen parallel to the prism sheet in one Is arranged at a distance next to this. 18. Optical projector to project one of one illuminated micro image coming light cone, characterized in that a first and a second mirror are generally arranged at right angles to each other, 809811/0723 that a prism sheet is arranged substantially at right angles to the second mirror, that a third mirror is arranged at an acute angle to the plane of the prism sheet that the The plane of the third mirror essentially through the intersection line of the first and the second mirror runs that at a distance next to the first prism sheet parallel to this a second prism sheet arranged that a fourth mirror with an edge next to the intersection of the third Mirror and the prism sheets is hinged, which is a screen on the other edge of the fourth mirror is articulated, and that the two pivot axes are parallel to each other. 19. Optical device, characterized by two prism sheets, the flat surfaces of which in one Spaced from each other and arranged parallel to each other, and that the homologous surfaces of the protruding ribs or prisms of these two sheets arranged parallel to each other in cross section are. 20. Optical projector for projecting one of one Illuminated micrograph coming light cone, characterized by a multitude of reflective Surfaces that cut and fold the light cone and one of which is reflective surface light, which occurs at an angle, the greater as a critical angle, while it reflects light incident at an angle that is smaller than the critical angle, characterized in that said reflective 809811/0723 -8- -s- Surface is formed by a prism sheet that a second prism sheet parallel to the first
Prism sheet is arranged at a distance next to this, that a last reflective surface is provided, which is arranged on its one edge about an axis perpendicular to the axis of the light cone pivotable, that the last reflective surface carries a screen that is on the opposite edge of the last reflective surface is pivotably articulated that the screen in a
Position parallel to and next to the last reflective surface is pivotable, and that the two pivot axes are parallel to each other. 809811/0723