Claims
- 1. A recording medium to which laser light is emitted, comprising a plurality of concavo-convex pits having three or more different levels of height or depth, each of said different levels representing a different recorded data value, and
- wherein a minimum value of the dimension of said concavo-convex pits measured along the direction normal to said recording medium is less than one eighth of the wavelength of said laser light.
- 2. A recording medium to which laser light is emitted, comprising a plurality of concavo-convex pits having three or more different levels of height or depth, each of said different levels representing a different recorded data value, and
- wherein a maximum value of the dimension of said concavo-convex pits measured along the direction normal to said recording medium is more than one fourth of the wavelength of said laser light.
- 3. A recording medium comprising a plurality of concavo-convex pits having three or more different levels of height or depth, each of said different levels representing a different recorded data value,
- wherein the different recorded value is reproduced by an evanescent wave in accordance with a determination of a degree which said concavo-convex pits influences said evanescent wave.
- 4. A recording medium according to claim 3, wherein said concavo-convex pits include four different levels of height or depth.
- 5. A recording medium according to claim 3, wherein said concavo-convex pits have a pit density which is approximately an inverse of a square of a wavelength or less of a light used to read information recorded in said recording medium.
- 6. A recording medium according to claim 3, wherein a minimum value of the dimension of said concavo-convex pits measured along the direction normal to said recording medium is less than one eighth of the wavelength of said laser light.
- 7. A recording medium according to claim 3, wherein a maximum value of the dimension of said concavo-convex pits measured along the direction normal to said recording medium is more than one fourth of the wavelength of said laser light.
Priority Claims (1)
Number |
Date |
Country |
Kind |
4-285756 |
Oct 1992 |
JPX |
|
Parent Case Info
This is a division of application Ser. No. 08/139,573, filed Oct. 20, 1993, now U.S. Pat. No. 5,463,609, issued on Oct. 31, 1995.
US Referenced Citations (12)
Foreign Referenced Citations (26)
Number |
Date |
Country |
0356201 |
Feb 1990 |
EPX |
0369671 |
May 1990 |
EPX |
0385337 |
Sep 1990 |
EPX |
0423662 |
Apr 1991 |
EPX |
0438054 |
Jul 1991 |
EPX |
0469879 |
Feb 1992 |
EPX |
257808 |
Mar 1986 |
FRX |
3620301 |
Jan 1987 |
DEX |
56-140536 |
Nov 1981 |
JPX |
58-102347 |
Jun 1983 |
JPX |
59-36347 |
Feb 1984 |
JPX |
60-020331 |
Feb 1985 |
JPX |
63-257921 |
Oct 1988 |
JPX |
1112552 |
May 1989 |
JPX |
1144252 |
Jun 1989 |
JPX |
1179225 |
Jul 1989 |
JPX |
2-179951 |
Jul 1990 |
JPX |
224445 |
Sep 1990 |
JPX |
2-308423 |
Dec 1990 |
JPX |
3-141032 |
Jun 1991 |
JPX |
3-201230 |
Sep 1991 |
JPX |
4-14620 |
Jan 1992 |
JPX |
4-26978 |
Jan 1992 |
JPX |
4-62090 |
Feb 1992 |
JPX |
5-34129 |
Feb 1993 |
JPX |
2111200 |
Jun 1983 |
GBX |
Non-Patent Literature Citations (2)
Entry |
Search Report for European Appl. 93117152.4, mailed Aug. 17, 1995. |
Journal of Applied Physics, vol. 66, No. 10, Nov. 15, 1989, Werner Hickel et al., "Surface Plasmon Microscopic Characterization Of External Surfaces", pp. 4832-4836. |
Divisions (1)
|
Number |
Date |
Country |
Parent |
139573 |
Oct 1993 |
|