Claims
- 1. An erasable display medium for displaying images in response to a signal current, comprising:
- a heating resistive layer having a first layer as a current path area for said signal current and a second layer as a converting area for converting said signal current into thermal energy;
- a conductive layer formed on said second layer of said heating resistive layer, said conductive layer comprising a current returning portion for returning said signal current to a ground portion; and
- an erasable thermochromic layer comprising a low molecular weight organic material having particles dispersed in a macro-molecular matrix material, wherein said erasable thermochromic layer is formed on said conductive layer for forming an image having an opaque portion and a transparent portion by said thermal energy being passed through said conductive layer.
- 2. The erasable display medium of claim 1, further comprising a background layer formed between the conductive layer and the erasable thermochromic layer, said background layer having a coloring material dispersed therein and generating a color corresponding to said transparent image.
- 3. The display medium of claim 2 wherein said background layer has carbon black dispersed therein.
- 4. The display medium of claim 1 whose heating resistive layer comprises at least two layers.
- 5. The display medium of claim 1 having a patterned contact resistance reducing layer on the heating resistance layer, said patterned contact resistance reducing layer comprising a dielectric resin and conducting particles.
- 6. The display medium of claim 1 allowing overwriting by a writing tool having a thermal point.
- 7. The display medium of claim 1 having a protective layer on the erasable thermochromic layer.
- 8. The display medium of claim 7, in which said protective layer has a thickness from 40 .mu.m to 50 .mu.m and a transparency in the visible light area of at least 15 percent, and functions as a support.
- 9. The display medium of claim 7 in which said protective layer has a thickness from 0.1 .mu.m to 20 .mu.m and a critical surface tension of not more than 30 dyne/cm.
- 10. A display medium of claim 1, wherein said first layer of said heating resistive layer comprises at least one conductive material dispersed in a binding component.
- 11. A display medium of claim 10, wherein said first layer of said heating resistive layer has a volume resistivity between 10.sup.-3 .OMEGA.cm and 10.sup.4 .OMEGA.cm, a thickness between 0.5 .mu.m and 200 .mu.m, and a heat resistance of at least 105.degree. C.
- 12. A display medium of claim 1, wherein said second layer of said heating resistive layer comprises one of a ceramic, a mixture of ceramics, a mixture of conductive filler and dielectric filler in heat resistant resin, and a mixture of ceramics and metallic materials.
- 13. A display medium of claim 12, wherein said second layer of said heating resistive layer has a volume resistivity between 10.sup.-1 .OMEGA.cm and 10.sup.8 .OMEGA.cm, a thickness between 50 nm and 20 .mu.m, and a heat resistance of at least 250.degree. C.
- 14. A display medium of claim 1, wherein said conductive layer comprises metal or conductive ceramic.
- 15. A display medium of claim 14, wherein said conductive layer has a volume resistivity of at least 10.sup.-2 .OMEGA.cm and a thickness between 50 nm and 5 .mu.m.
- 16. A display medium of claim 1, wherein said organic material has between 35 and 600 carbon atoms in a straight chain and wherein said macro-molecular matrix material and said organic material have a weight ratio between 2:1 and 30:1.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3-355579 |
Dec 1991 |
JPX |
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Parent Case Info
This application is a continuation, of application Ser. No. 07/995,336, filed Dec. 23, 1992, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5157011 |
Okabe et al. |
Oct 1992 |
|
5158926 |
Hotta et al. |
Oct 1992 |
|
Foreign Referenced Citations (2)
Number |
Date |
Country |
429010 |
May 1991 |
EPX |
2-258287 |
Oct 1990 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
995336 |
Dec 1992 |
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