JPS6210418B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microfissure reader, and more particularly to a compact microfissure reader in which the projected microimage of the microfissure is reflected several times before hitting an observation screen.

Many of the embodiments of the present invention represent improvements on the device shown in Kapany et al., US Pat. No. 3,941,467. As described in that patent, the microfissure reader folds a projected conical light beam by sequentially reflecting it off a plurality of reflective surfaces until it impinges on a viewing screen. The plurality of reflective surfaces are defined by several external surfaces of the trapezoidal solid. One of the trapezoidal reflective surfaces serves a dual function, forming one of the reflective surfaces and subsequently passing the reflected light for final image formation on the viewing screen. The method taken by Kapany et al. to achieve such a result was to select a certain angle of the reflective surface so that the first ray of light striking the bifunctional surface was below a certain critical angle for total internal reflection. It is designed to hit the target at a large angle of incidence. The critical angle depends on the refractive index of the material of which the trapezoid is made. Kapany
The configuration also uses a Fresnel lens. It is not essential to the operation of the device and is only used to provide a brighter and more evenly illuminated picture, especially at the edges.

According to the invention, a similar effect occurs in that the light cone is effectively folded back several times before hitting the viewing screen, but instead of a solid trapezoid or other block of light-transparent material. There is no need to adopt. Instead, a similar bifunctional surface is defined by a series of prisms defining one prism sheet. The prism sheet performs a similar function to the bifunctional surface of Kapany et al. and also serves to focus the final image onto the viewing screen. The present invention
The advantage over the configuration of Kapany et al. is that it provides a considerable reduction in weight and cost. Therefore,
Instead of relatively heavy and expensive hard plastic blocks (trapezoids), the reflective surfaces are defined by plane mirrors in the form of sheets or panels that are inexpensively made and positioned relative to each other.

Furthermore, since Kapany et al. use a solid block made of a transparent material, it is necessary to make the projection distance of the light cone longer for the same size observation area. , the projection distance is n times the projection distance required to implement the present invention. For example, if the viewing distance of Kapany et al.'s model is 9 inches (228.6
mm), the present invention requires a projection distance of about 6 inches (152.4 mm). The smaller the projection distance, the more compact the viewing device will be for a given size viewing screen.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Referring first to FIG. 1, a microfissure reader or observation device constructed in accordance with one embodiment of the present invention is schematically illustrated. 10 is a projection lens or lens system for projecting microimages from a microfissure (not shown) or other reduced photographs. The chief ray of the light cone projected from the projection lens 10 is indicated at 12 and first strikes the mirror 14. The light beam then strikes a second mirror 16 and then a third or final mirror 18 for final imaging and viewing on a viewing screen 20. Pivot elements 22 and 24 are positioned as shown relative to mirror 18 and viewing screen 20.

As shown in Figure 2, the device first moves to pivot 2.
4 and then around pivot 22. 26 is the element of the observation device (cassette 72,
Audio speaker 73, electronic circuit 74, battery 7
5, drive device 77, and motor 79) are shown as a whole.

The perspective view of FIG. 3 shows the general shape and size proportions of the viewing device in the extended or viewing position.

FIG. 4 shows another embodiment similar to that shown in FIGS. 1 to 3, except that there is a viewing screen in front of the projected light cone, whose principal axis is indicated at 12. This is Artaud's US Patent No.
No. 3,667,839, the collapsible viewing device shown in FIGS. 1 to 4 of that patent is similar to the embodiment of FIGS. Although a collapsible arrangement is shown that impinges on two reflective surfaces, the apparatus shown in FIGS. In addition, the folding action is different in order to make the device more compact.

Figure 5 shows the previously mentioned U.S. patent of Kapany et al.
The prior art device of No. 3941467 is shown. 30 indicates the main optical elements as a whole. 31 denotes a solid block of transparent material through which a light cone whose apex is indicated at 32 is projected. The light cone represents the light from the microimage. The chief ray is 33
, which falls on the first reflective surface 34 . From there it impinges at a critical angle or more with respect to the normal to the solid surface 35 and is then reflected onto a reflective surface 37 . From here the light becomes visible perpendicularly out from the surface 35. A widening dotted line adjacent to the cone apex 32 will be observed. They illustrate the bending effect that light undergoes when it passes through transparent material 31 from air.

Referring now to FIGS. 6 and 7, there is shown an embodiment of a compact optical observation device that employs bifunctional surfaces and is advantageous in terms of both size and cost. In FIG. 6, reference numeral 12 designates the central ray of the projected light cone carrying the micro-image to be observed;
4 and then the prism sheet 44.
It then undergoes total internal reflection at the top surface of the prism sheet, as in the case of surface 35 of the Kapany et al. device in FIG. It then exits perpendicularly toward the prism sheet and then toward the viewing screen 46. Although the light is shown passing straight through the prism sheet 44 in FIG. 6, it will be appreciated that the light from the mirror 16 is refracted as shown in FIG. 7 as it passes through the prism sheet 44.

FIG. 7 is an enlarged view of a portion of the screen 46 and prism sheet 44 of FIG. 6, and 48 indicates the gap between the prism sheet 44 and the visible screen 46. Prism sheet 44 is defined by a plurality of ridges on one surface thereof, and the sheet is transparent. Each ridge has two sides, and the cross section of each side is generally straight, although one of the two sides may be curved. In the illustrated prism sheet, all the ridges are straight and parallel to each other.

However, a ridge with an elliptical contour may also be employed, such that the axis of the light cone defines one of the two foci of the nested ellipse. FIG. 8 shows one such embodiment of a prism sheet.
Prism sheet 44 should not be confused with the externally similar Fresnel lens. The individual ridges making up the prism sheet are similar in cross-section to the previous embodiment, but are oval in profile. The ridge is indicated by 50 and 52 indicates the intersection of the ray 12 of the light cone with the prism sheet. It will be appreciated that point 52 is one focal point of a single elliptical ridge.

Referring now to Figures 9a and 9b, 2
and four prisms are shown respectively. When a single prism sheet is employed in the reader as shown in FIGS. 6 and 7, the viewing screen is placed adjacent to the flat surface of the prism sheet. However, if the light passing through the first prism sheet is subsequently reflected, it is necessary to include a second prism sheet in order not to change the direction of the light rays. However, if the thickness of the prism sheet is too thick, the image on the rear projection screen will be severely distorted due to intersecting light rays, as shown in FIG. 9a. However, if the number of prisms is large, e.g. 200 prisms per inch (200 prisms/25.4 mm), the distortion becomes negligible to the eye and the resulting distortion cannot be resolved by the human eye. right.

To improve the image on the screen, a second pair of prism sheets may be placed in close proximity to the first pair of prism sheets, thereby canceling out the intersection of the rays, as shown in Figure 9b. I can do it. It should be noted that in all of the embodiments illustrated as using a pair of prism sheets, the optical system can be improved by adding a prism pair as shown in Figure 9b.

In FIG. 9a, the first prism sheet 54 is shown and includes surfaces 56 and 58 in its representative raised portions. Air gap 60 is between the flat surface of prism sheet 54 and the flat surface of second prism sheet 62. Surfaces 64 and 66 on the typical ridges of prism sheet 62 correspond to surfaces 56 and 58. Surface 58 is parallel to surface 64 and surface 56 is parallel to surface 66. Additionally, one or both of the homologous surfaces 58 and 64 may be curved to effectively define the lens. Similarly, one or both of homologous surfaces 56 and 66 may be curved.

10 and 11 show another embodiment employing two projection lenses. In FIG. 11, 12 and 12' indicate the principal axes of the two projected light cones, each light cone corresponding to a respective portion of two parallel tracks carried by optical film on the Philips cassette 72. . The leader is indicated generally by 28'.

FIG. 12 shows another embodiment similar to the previous embodiment, which is a standard 4" x 6" (101.6mm x 101.6mm)
A compact reader is shown that is capable of accommodating a microfissile or a Philips cassette, such as a 152.4 mm (152.4 mm) microfissure. The microfissure is indicated at 70 and uses a projection lens 10, while the cassette is indicated at 72 and uses a projection lens 10'. Cassette 7
It should be understood that when using the mirror 11, the mirror 11 is pivoted out of the optical path. In this way, microfissures or cassettes can be used for projection.

Referring now to FIGS. 13 and 14, another embodiment of a compact viewing device is shown. 76
is a scaled depiction of a first mirror that receives a projected light cone from a cassette or other optical information carrier. 78 indicates a second mirror, and 80 indicates a third mirror. As before, 44 indicates a prism sheet, and 46 indicates an observation screen. The chief ray is indicated by 12. The operation of the device is similar to that described above with respect to the other embodiments. However, the reflective surfaces, particularly the first and second reflective surfaces, are substantially parallel. As previously mentioned, light striking the prism sheet 44 above the critical angle will be reflected, and light rays substantially perpendicular to the prism sheet will pass through and be observed on the screen 46.

The embodiment of FIG. 14 differs from the embodiment of FIG. 13 in that it includes an additional mirror 82 coupled to a viewing screen 84 and pivots 86,88. When the screen is not in use, it is folded clockwise about pivot 88 until it is parallel to mirror 82, and then both elements are folded clockwise about pivot 86. In addition, a pair of parallel prism sheets with a gap shown by 54 and 62 are employed, and their operation and arrangement are as follows.
This is similar to what was said regarding the figure.

Other variations are shown in FIGS. 15 and 16, where 90 is a first mirror, 92 is a second mirror, 94 is a third mirror, 96 is a viewing screen, and 12 is a cassette or other. shows the principal axis ray of the light cone projected from the information storage device. The viewing screen includes a pivot 98 connecting the screen to the top of the mirror 94;
The bottom of mirror 94 has a pivot 100 located on the left side of mirror 92 in FIG. 102 indicates a transparent sheet such as a glass plate. The operation of the apparatus will be clear from FIG. When folding the device when no viewing is to be performed, the screen 96 is pivoted clockwise about the axis 98 until it is parallel to the mirror 94. These two elements are then pivoted counterclockwise about pivot 100 until they are parallel to mirror 92. The glass plate 102 is for protecting the inside of the device when it is in the folded state.

Figure 17 shows a similar configuration, the main differences being the folding method and the use of two bifunctional prism sheets. Mirror 93 is next to the last reflective surface and mirror 94 is the last reflective surface. Reference numeral 96 indicates an observation screen, and reference numeral 12 indicates a chief ray. When folding the device shown in Figure 17, mirror 9
4 to the right and its bottom slides along the top of the viewing device, the viewing screen 96 rotates clockwise about the axis 100.

Referring to FIG. 18, another embodiment of a compact reader according to the present invention is shown. 110
denotes the first reflective surface (ignoring any small mirrors near the apex of the projected light cone), and 112 denotes the second
44 represents the reflective surface of the observation screen 46
2 depicts a prism sheet having a gap associated with the prismatic sheet. 113 indicates a groove into which a microfissure is inserted. It will be appreciated that element 26 has been modified to include a flip cassette carrying optical information instead of a microfiche. The projected light cone from the stored micro-information has a chief ray indicated by 12 as previously discussed and impinges on surfaces 110 and 112 as shown. The reflective surface 114 is positioned as shown and extends upwardly to the left as shown in FIG. 18 until it abuts the left edge of the prism sheet. Prism 44-2
Functional effects are the same as described above.

FIG. 19 shows a modification of the device shown in FIG. 18, except that another mirror 115 and a viewing screen 116 have been added, the screen 116 being attached to the top of the mirror 115 by a pivot 120,
15 has a lower pivot 122. 1st
The optical effect of the example in FIG. 9 will be clear. When folding the device, the screen 116 is rotated clockwise about the axis 120 until it is parallel to the mirror 115, and then these two elements are folded clockwise about the pivot 122 towards the top of the device.

44 of FIG. 7 employed in many of the embodiments described above.
and prism sheets such as 54 and 62 in Figure 9a are "Light
10 and 11 of U.S. Pat. No. 3,728,422 and U.S. Pat. No. 3,728,422. A number of generally rectangular shims made of metal are bent to slide over each other and thus
It is assumed that the staggered relationship shown in the figure exists (except that the ends of one set of shims are square as shown in FIG. 10 rather than offset as shown at 72). Furthermore, the edges are not too far apart from each other as shown in FIG. 11, but are instead separated so that the end cross-section is similar to that of the prism sheet of FIG. 7 of the present application. or,
The ends of the shims are mirror polished. As a result, the shim assembly can be employed as a mold or as a master for electroforming. The mirror-polished ends of the shims produce the desired optically flat surfaces of the individual ridges of the prism sheet, such as the flat surfaces 56, 58 of the prism sheet 54 of FIG. 9a of this application.

The present invention also relates to a microfissure and a cassette carrying distributed sub-images of each original information, and/or
It can be used with lensesettes that are integrated with a microfisseur. For more information on such techniques, see, for example, U.S. Pat.
No. 3995288, No. 3967289, No. 3806708 and No.
Reference may be made to No. 3704068. The present invention can be used for both still images and moving images. These uses are also within the scope of this invention.

It should be noted that the prism sheet should be made as thin as possible, and that the prism sheet should be supported or positioned so that it does not warp with changing surroundings or conditions of use.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a simple folding mirror configuration according to the invention. 2 is a partial schematic diagram of the device of FIG. 1 in a folded state; FIG. Figure 3 is the first
FIG. 3 is a perspective view of the observation device of FIG. 2 in an open position; FIG. 4 shows a modification of FIG. 1. Fifth
The figure shows the prior art device shown in U.S. Pat. No. 3,941,467 to Kapany et al. FIG. 6 shows an embodiment similar to FIG. 1, but employing a prism sheet that performs two functions. FIG. 7 is an enlarged view of a part of FIG. 6. FIG. 8 shows a modification of the prism sheet. Figure 9a is a diagram similar to Figure 7, with the mirror in the first
This shows how two prism sheets are used when placed immediately after the prism sheet in the optical path. 9th
Figure b is similar to Figure 9a and shows the use of the second pair of prism sheets. FIG. 10 is a diagram similar to FIG. 2, showing a complete observation device constructed according to the principles shown in FIG. FIG. 11 is a cross-sectional view along line 11--11 of FIG. 10 showing two lenses for projection micro-images based on two parallel tracks placed on a Philips cassette filmstrip. Figure 12 shows a portion of a diagram similar to Figure 10, showing a Philips cassette and a standard 4" x 6"
This shows a reader that can be used for both microfishes (mm). FIG. 13 is a partial view of another embodiment of the invention. FIG. 14 shows the device shown in FIG. 13 in an open position. FIG. 15 shows still another modification of the present invention. FIG. 16 shows FIG. 15 in a folded position. FIG. 17 shows the same type of viewing device as shown in FIG. 15, except that the viewing screen is foldable and the mirrors are different. FIG. 18 shows yet another embodiment. FIG. 19 is a diagram of the reader of FIG. 18 with the addition of a mirror and a folding viewing screen.

Claims (1)

[Claims] 1. An optical projection device of the type that projects a cone of light from an illuminated micro-image, comprising a plurality of reflective surfaces that capture and fold the cone of light, one of the reflective surfaces at an angle greater than a critical angle. reflects incident light at a critical angle but transmits incident light at an angle smaller than a critical angle, the one reflective surface is defined by a prism sheet, and the observation screen is parallel to and adjacent to the prism sheet. An optical projection device characterized in that there is a gap from the prism sheet.