OPTICAL DEFLECTION DEVICE, IMAGE DISPLAY DEVICE, SIGNAL DEVICE, IMAGE RECORDING MEDIUM, AND IMAGE REPRODUCTION METHOD

Abstract

[Problem] Propagation of parallel light inside thin glass or plastic material had not been considered to be feasible because of difficulties in producing parallel light with large aspect ratio and in light-guiding it into thin material. For this reason, there had been a problem that holograms of edge-lit reproduction type were not being brought to practical use.

[Means for Solution] A compact, simple collimator optics has been successfully made by placing a holographic diffraction grating close to a diverging light source to propagate it at the critical angle inside the medium. By making an array of this diffraction grating it has become possible to propagate parallel light of any aspect ratio inside a thin plate. Hitherto unrealized image display devices and signal devices have become possible by using the holographic diffraction gratings as described in the foregoing, or other diffraction optical elements, to introduce light from a plurality of light sources, in combination with edge-lit reproduction type image holograms.

Claims

1.-27. (canceled)

28. An optical deflection device wherein, comprising a plurality of light sources, a transparent medium of optical refractive index 1.3 or greater, and a plurality of holographic diffraction gratings placed on a part of the said transparent medium without interposition of an air gap, each of the said plurality of light sources having the same angle of divergence and the same wavelength components of emitted light and being placed in a position facing each of the said holographic diffraction gratings, each of the said holographic diffraction gratings deflecting the diverging light incident from each of the said light sources as parallel light with a specified angle in excess of the critical angle of the said transparent medium, and the said parallel light propagating inside the said transparent medium, each of the said holographic diffraction gratings being placed without any gap in the direction perpendicular to the light-guiding direction of the said parallel light in the said transparent medium.

29. An optical deflection device described in claim 28 wherein imparting to each of the said holographic diffraction gratings an optical function of diffusing light, as described in the foregoing, not in the direction perpendicular to, but only along, the propagation direction of the said parallel light propagating inside the said transparent medium.

30. An optical deflection device wherein comprising at least two light sources, a transparent medium of optical refractive index 1.3 or greater, holographic diffraction gratings or refractive optical functional elements facing each of the said light sources and arranged with separations matching those among the light sources, and barrier walls placed in a manner which prevents incidence of light from the said light sources into neighboring holographic diffraction gratings or refractive optical functional elements, the said holographic diffraction gratings being placed on a part of the said transparent medium without interposition of any air gap, the said holographic diffraction gratings or the said refractive optical functional elements deflecting the diverging light incident from each of the said light sources as parallel light with a specified angle in excess of the critical angle of the said transparent medium, and the said parallel light propagating inside the said transparent medium.

31. An optical deflection device described in claim 30 wherein placing in the optical path of the said parallel light an optical functional element described in the foregoing, which does not have a diffusing function in the direction perpendicular to, but only along, the propagation direction of the said parallel light propagating inside the transparent medium.

32. An optical deflection device described in claim 28 wherein carrying an inscription of at least one item of information describing the displayed color, wavelength, angle of illumination, angle of divergence or data for inverse compensation, for the image recording medium with which the said optical deflection device is to be engaged.

33. An optical deflection device described in claim 30 wherein carrying an inscription of at least one item of information describing the displayed color, wavelength, angle of illumination, angle of divergence or data for inverse compensation, for the image recording medium with which the said optical deflection device is to be engaged.

34. An image reproduction method for viewing a hologram image by attaching, without interposition of an air gap, an edge-lit hologram produced by a separate process on to the face of a transparent medium of optical refractive index 1.3 or greater that is a cylinder or a partial cylinder with curvature, by illuminating with at least two light sources and holographic diffraction gratings or refractive optical functional elements facing each light source upon preventing illumination by light from adjacent light sources, by using the said holographic diffraction gratings or refractive optical functional elements to make light from the said light sources to be incident to the said transparent medium at an angle in excess of the critical angle of the said transparent medium, and by making the said edge-lit hologram be illuminated by light propagating inside the said transparent medium to reproduce a hologram image.

Description

BRIEF EXPLANATION OF THE FIGURES

[0121] FIG. 1 An illumination device for an edge-lit reproduction hologram (First Embodiment) in which the present invention is applied

[0122] FIG. 2 An illumination device for a full color edge-lit reproduction hologram (Second Embodiment) in which the present invention is applied

[0123] FIG. 3 An illumination device for a time-sequential edge-lit reproduction hologram (Third Embodiment) in which the present invention is applied

[0124] FIG. 4 A switching device with an edge-lit reproduction hologram display function (Fourth Embodiment) in which the present invention is applied

[0125] FIG. 5 A cylindrical edge-lit reproduction device (Fifth Embodiment) in which the present invention is applied

[0126] FIG. 6 A rotating cylinder edge-lit reproduction device (Sixth Embodiment) in which the present invention is applied

[0127] FIG. 7 A depth-wise multilayered edge-lit reproduction device (Seventh Embodiment) in which the present invention is applied

[0128] FIG. 8 An example of a positioning device for light sources and holographic diffraction gratings, in which the present invention is applied

[0129] FIG. 9 An example of barriers placed between holographic diffraction gratings by applying the present invention

[0130] FIG. 10 An example of louver films placed between holographic diffraction gratings by applying the present invention

[0131] FIG. 11 An example of a place where traffic signals are installed that require control of the viewing angles

[0132] FIG. 12 An example of the configuration of a traffic signal in which the present invention is applied

[0133] FIG. 13 An example of a place where it is appropriate to install a cylindrical traffic signal of the present invention

[0134] FIG. 14 An example of the configuration of a cylindrical traffic signal of the present invention

[0135] FIG. 15 An example of the edge-lit light-introduction path of the present invention

[0136] FIG. 16 First example of the cylindrical edge-lit light-introduction path of the present invention

[0137] FIG. 17 Second example of the cylindrical edge-lit light-introduction path of the present invention

[0138] FIG. 18 An example of the edge-lit light-introduction path of the present invention

[0139] FIG. 19 An example of the cylindrical edge-lit light-introduction path of the present invention

[0140] FIG. 20 Diagram explaining the compensation in the present invention to obtain uniform brightness of the hologram image

[0141] FIG. 21 Diagram explaining the compensation in the present invention for the distortion of the hologram image

[0142] FIG. 22 Diagram explaining the cylindrical display of the present invention

EXPLANATION OF NOTATIONS

[0143] 101, 201, 801 - - - transparent substrate [0144] 102, 202 - - - recording medium for image hologram [0145] 103, 203, 803 - - - medium for reflection holographic diffraction grating [0146] 104, 204, 804 - - - holographic diffraction grating [0147] 105, 205, 805 - - - LED [0148] 106 - - - LED substrate [0149] LA, LB, LC, LD, LE, LF - - - LED [0150] HA, HB, HC, HD, HE, HF - - - holographic diffraction grating [0151] 700, 710, 730, 750 - - - cylindrical hologram display [0152] 701, 711, 731, 751 - - - cylinder [0153] 704, 715, 735, 755 - - - light source [0154] 761 - - - conical mirror