Information-bearing devices and projection display systems therefor

• US 3,895,866 A
• Filed: 11/29/1972
• Issued: 07/22/1975
• Est. Priority Date: 12/03/1971
• Status: Expired due to Term

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: Alfred De Quervain, Peter Wild
• Inventors: Wild, Peter, de Quervain, Alfred
• Primary Examiner(s): Aegerter, Richard E.
• Assistant Examiner(s): Mirabito, A. J.
• Application Number:
  US05/310,263
• Time in Patent Office: 965 Days
• Field of Search: 353/120,122,30 350/16LC
• US Class Current: 353/30
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G03B 21/005 Projectors using an electronic spatial light modulator but not peculiar thereto
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 9/3108 by using a single electronic spatial light modulator

Abstract

In the disclosed system a projector optically displays the information content of a transparency. In the transparency a liquid crystalline substance is sandwiched between two transparent plates. Transparent electrodes on the inner faces of the plates are energized to vary the electrical fields to which portions of the substance are subjected. The variation in the fields changes the optical properties of the substance at specific locations. Thus, voltages applied to the electrodes impart optical changes and hence dynamic, i.e. varying, optical in formation to the transparency. Static, i.e. fixed, optical information is added to the varying information by superposing an optical image on the image formed by the substance. This can be done by cementing a film onto the outer surface of the plate or by etching the outer surface of the plate. When the image content of the transparency is projected onto a projection surface it can carry information similar to a display panel. The static information can be formed from spacers mounted between the plates.

Claims

1. A unitary, optically projectable, composite transparency having an electrically variable, optically readable information content and arranged to be interposed between a projector and a display means, the transparency comprising a first portion bearing static optical information, said first portion including distinct indicia, a second portion bearing dynamic information in intimate contact with the first portion and including a liquid crystalline substance having regions whose optical states can be selectively changed, and control means coupled to the liquid crystalline substance for selectively changing the optical states of the regions.

2. An apparatus as in claim 1, wherein said liquid crystalline substance is a nematic liquid crystal.

3. An apparatus as in claim 1, wherein said liquid crystalline substance is a cholesteric liquid crystal.

4. An apparatus as in claim 1, wherein said liquid crystal substance is a mixture of between 85 and 97% nematic liquid crystal and cholesteric liquid crystal.

5. An apparatus as in claim 1, wherein said second portion further includes a pair of light-permeable plates sandwiching the liquid crystalline substance between them, and a pair of spacers between the plates for spacing the plates a distance of 5 Mu to 50 Mu from each other.

6. An apparatus as in claim 1, wherein said second portion includes a plurality of light-permeable electrically conductive electrode means responsive to said control means for establishing and varying potentials within the third and fourth regions.

7. An apparatus as in claim 5, wherein said plates include surfaces facing the liquid crystalline substance, and wherein said second portion includes a plurality of light-permeable electrically conducting electrode means mounted on the surfaces of said plates facing the liquid crystal substance and responsive to said control means for establishing and changing potentials within the third and fourth regions.

8. An apparatus as in claim 6, wherein said electrode means include a plurality of strips forming a matrix.

9. An apparatus as in claim 7, wherein said electrode means include a plurality of elongated electrodes forming a matrix.

10. An apparatus as in claim 5, wherein said spacers include glass fibers having a diameter corresponding to the distance between said plates.

11. An apparatus as in claim 6, wherein said plates each include surfaces facing away from said liquid crystalline substance, said first portion being disposed on one of the surfaces facing away from the liquid crystal substance.

12. An apparatus as in claim 7, wherein spacers are at least partially formed from glass fibers whose diameters correspond to the distance between the plates.

13. An apparatus as in claim 11, wherein said first portion includes a transparent film and an adhesive securing said transparent film to the surface of one of the plates facing away from said substance.

14. An apparatus as in claim 7, wherein said first portion includes a lacquer layer located between the two plates and spacing the plates from each other.

15. An apparatus as in claim 7, wherein said electrode means each include an end contact area near the marginal portions of said plates.

16. An apparatus as in claim 15, further comprising spring contact elements connected to said contact areas.

17. An apparatus as in claim 15, wherein said control means includes electricAl means for contacting said contact areas.

18. A unitary, optically projectable, composite transparency having an electrically variable, optically readable information content and arranged to be interposed between a projector and a display means, the transparency comprising, in combination, a first static information bearing portion, and a second dynamic information bearing portion disposed in intimate contact with the first portion, the second portion including a liquid crystalline substance, a pair of light-permeable plates sandwiching the liquid crystalline substance between them, a plurality of light-permeable electrically conductive electrode means mounted on the surfaces of said plates facing the liquid crystalline substance for establishing and changing potentials within the liquid crystalline substance, and a plurality of spacers disposed between the plates for spacing the plates a distance of 5 Mu to 50 Mu from each other, the spacers being at least partially formed from glass fibers whose diameters correspond to the distance between the plates, at least a portion of said plurality of spacers also forming a part of said first portion.

19. An apparatus as in claim 8, wherein the proportion of the plurality of said spacers forming a part of said first portion are light-impermeable and electrically non-conductive.

20. An apparatus as in claim 18, wherein said proportion of said spacers which form part of said first portion are foils exhibiting colors and passing light corresponding to the colors which they exhibit, said foils being electrically non-conductive.

21. An apparatus as in claim 20, wherein said foils are of different colors.

22. An apparatus as in claim 1, wherein said distinct indicia are different colors.

23. An apparatus as in claim 1, wherein said distinct indicia are different symbols.

24. An optical projection system for projecting an image on a display, comprising, a unitary optically-projectable composite transparency having an electrically-variable optically-readable information content, said transparency including a first portion bearing static information, said first portion including distinct indicia, a second portion bearing dynamic information in intimate contact with the first portion, the second portion including a liquid crystalline substance having regions whose optical states can be selectively changed, control means coupled to the crystalline substance for selectively changing the optical states of the regions, and means for illuminating the transparency to project an image of the information content thereof.

25. An apparatus as in claim 24, wherein said liquid crystalline substance is a nematic liquid crystal.

26. An apparatus as in claim 24, wherein said liquid crystalline substance is a cholesteric liquid crystal.

27. An apparatus as in claim 24, wherein said second portion further includes a pair of light-permeable plates sandwiching the liquid crystalline substance between them, and a pair of spacers between the plates for spacing the plates a distance of 5 Mu to 50 Mu to each other.

28. An apparatus as in claim 27, wherein said plates include surfaces facing the liquid crystalline substance, and wherein said second portion includes light-permeable electrically conducting electrode means mounted on the surfaces of said plates facing the liquid crystal substance for establishing and changing potentials within the liquid crystal substance so as to establish and change particular optical characteristics of said substances.

29. A unitary, optically projectable composite transparency having an electrically variable, optically readable information content and arranged to be interposed between a projector and a display means, the transparency comprising, in combination, a first static information bearing portion, and a second dynamic information bearing portion in intimate contact with the first portion, the second portion including a liquid crystalline substance, a pair of light-permeable plates sandwiching the liquid crystalline substance between them, a plurality of light-permeable electrically conductive electrode means mounted on the surfaces of said plates facing the liquid crystalline substance for establishing and changing potentials within the liquid crystalline substance, and a pair of spacers between the plates for spacing the plates a distance of 5 Mu to 50 Mu from each other, the first portion including a metal layer sandwiched between one of the plates and the electrode means on said plate, said metal layer being insulated from said electrode means by an insulating layer, said last-mentioned metal layer being light-impermeable.

30. An apparatus as in claim 29, wherein the metal layer is made of gold about 1 Mu thick and the insulating layer is a silicon oxide layer approximately 1 Mu thick.

31. A unitary, optically projectable composite transparency having an electrically variable, optically readable information content and arranged to be interposed between a projector and between a display means, the transparency comprising, in combination, a first static information bearing portion, and a second dynamic information bearing portion in intimate contact with the first portion, the second portion including a liquid crystalline substance, a pair of light-permeable plates sandwiching the liquid crystalline substance between them, a plurality of light-permeable electrically conductive electrode means mounted on the surfaces of said plates facing the liquid crystal substance for establishing and changing potentials within the liquid crystalline substance, and a pair of spacers disposed between the plates for spacing the plates a distance of 5 Mu to 50 Mu from each other, the first portion including a thin metal layer located between one of said plates and the electrode means on the one of said plates, an insulating layer separating the metal layer from said electrode means, said metal layer being light-permeable and colored.