Optical disk

Claim 2

An optical disk comprising: a disk plate having a light reflective layer; a tracking guide spirally formed on said light reflective layer of said disk plate so as to establish a guide path for a laser beam irradiating said optical disk, said tracking guide including plural guide segments separated from one another along said guide path so as to define a respective plurality of flat light-reflective regions between adjacent ones of said guide segments, each said guide segment being defined by a groove having a predetermined depth h 0 ; and preformation pits formed by said light reflective layer of said disk plate and defined in respective ones of said light reflective regions, said preformation pits having a depth h 0 of substantially the same dimension as the predetermined depth h 0 of each said groove of said guide segment.

Claim 3

An optical disk according to claim 1, wherein the depth h 0 of each said groove of said guide segments and said preformation pits is given by: {(2n-1)/8-1/10}λ≦h.sub.0 ≦{(2n-1)/8+1/10}λ, where n is an integer and λ is a wavelength of a laser beam irradiating said optical disk.

Claim 4

An optical disk according to claim 1, wherein the depth h 0 of each said groove of said guide segments and said preformation pits is given by: (1/40)λ≦h.sub.0 ≦(9/40)λ, where λ is a wavelength of the laser beam irradiating said optical disk.

Claim 5

An optical disk according to claim 1, wherein the depth h 0 of each said groove of said guide segments and said preformation pits is about λ/8, respectively.

Claim 6

An optical disk according to claim 1, wherein each of said preformation pits has a width substantially the same as that of said groove grooves of said guide segments.

Claim 7

An optical disk according to claim 1, wherein each of said guide segments has a width W 0 /2, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective regions of said optical disk.

Claim 8

An optical disk according to claim 1, wherein each of said preformation pits has a width of W 0 /2, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective regions of said optical disk.

Claim 9

An optical disk according to claim 1, wherein each of said preformation pits has a width smaller than that of said groove of said guide segments.

Claim 10

An optical disk according to claim 8, wherein each of said preformation pits has a width W 0 /3, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective regions of said optical disk.

Claim 11

An optical disk according to claim 1, further comprising information pits formed by removing the light reflective layer in said groove of selected ones of said guide segments.

Claim 12

An optical disk according to claim 1, wherein each guide segment has a V-shaped section.

Claim 13

An optical disk according to claim 1, wherein each said guide segment has a U-shaped section.

Claim 14

An optical disk according to claim 1, wherein each said guide segment has an inverted trapezoid section.

Claim 15

An optical disk comprising: a disk plate having a light reflective layer; a tracking guide spirally formed on said light reflective layer of said disk plate so as to establish a guide path for a laser beam irradiating said optical disk, said tracking guide including plural guide segments separated from one another along said guide path so as to define a respective plurality of flat light-reflective regions between adjacent ones of said guide segments, each said guide segment being defined by a ridge having a predetermined height h 0 ; and projections formed by said light reflective layer of said disk plate and projecting from predetermined ones of said light-reflective regions, said projections also having a height h 0 of substantially the same dimension as the predetermined height h 0 of said ridge of each said guide segment.

Claim 16

An optical disk comprising: a disk plate having a light reflective layer; a tracking guide spirally formed on said light reflective layer of said disk plate so as to establish a guide path for a laser beam irradiating said optical disk, said tracking guide including plural guide segments separated from one another along said guide path so as to define a respective plurality of flat light-reflective regions between adjacent ones of said guide segments, each said guide segment being defined by a ridge having a predetermined height h 0 ; and projections formed by said light reflective layer of said disk plate and projecting from predetermined ones of said light-reflective regions, said projections also having a height h 0 of substantially the same dimension as the predetermined height h 0 of said ridge of each said guide segment.

Claim 17

An optical disk according to claim 14, wherein the height of each said ridge and said first projections is given by: {(2n-1)/8-1/10}λ≦h.sub.0 ≦{(2n-1)/8+1/10}λ, where n is an integer and λ is a wavelength of a laser beam irradiating said optical disk.

Claim 18

An optical disk according to claim 14, wherein the height of each said ridge and said projections is given by: (1/40)λ≦h.sub.0 ≦(9/40)λ, where λ is a wavelength of the laser beam irradiating said optical disk.

Claim 19

An optical disk according to claim 14, wherein the height of each said ridge and said projections is preset at about λ/8 each.

Claim 20

An optical disk according to claim 14, wherein each said projection has a width substantially the same as that each of said ridge.

Claim 21

An optical disk according to claim 14, wherein each of said guide segments has a width W 0 /2, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective regions of said optical disk.

Claim 22

An optical disk according to claim 14, wherein each said projection has a width W 0 /2, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective regions of said optical disk.

Claim 23

An optical disk according to claim 14, wherein each of said projections has a width smaller than that of said ridge of each said guide segment.

Claim 24

An optical disk according to claim 21, wherein each of said projections has a width W 0 /3, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective of said optical disk.

Claim 25

An optical disk according to claim 14, further comprising information pits formed by removing the light reflective layer on said ridge of predetermined ones of said guide segments.

Claim 26

An optical disk comprising: a disk plate having a light reflective layer; a tracking guide spirally formed on said light reflective layer of said disk plate so as to establish a guide path for a laser beam irradiating said optical disk, said tracking guide including plural guide segments separated from one another along said guide path so as to define a respective plurality of flat light-reflective regions between adjacent ones of said guide segments, each said guide segment being defined by a groove having a predetermined depth h 0 ; plural recesses formed by said light reflective layer of said disk plate and located in predetermined ones of said flat light-reflective regions, each said recess having a depth h 0 of substantially the same dimension as the predetermined depth h 0 of each said groove; and wherein said flat light-reflective regions include flat bridge sections defined (i) between said recesses and an adjacent one of said grooves, and (ii) between adjacent ones of said recesses said bridge sections representing code information.

Claim 27

An optical disk comprising: a disk plate having a light reflective layer; a tracking guide spirally formed on said light reflective layer of said disk plate so as to establish a guide path for a laser beam irradiating said optical disk, said tracking guide including plural guide segments separated from one another along said guide path so as to define a respective plurality of flat light-reflective regions between adjacent ones of said guide segments, each said guide segment being defined by a groove having a predetermined depth h 0 ; plural recesses formed by said light reflective layer of said disk plate and located in predetermined ones of said flat light-reflective regions, each said recess having a depth h 0 of substantially the same dimension as the predetermined depth h 0 of each said groove; and wherein said flat light-reflective regions include flat bridge sections defined (i) between said recesses and an adjacent one of said grooves, and (ii) between adjacent ones of said recesses said bridge sections representing code information.

Claim 28

An optical disk according to claim 24, wherein the depth d 0 of each said groove and said recesses is given by: {(2n-1)/8-1/10}λ≦h.sub.0 ≦{(2n-1)/8+1/10}λ, where n is an integer and λ is a wavelength of a laser beam irradiating said optical disk.

Claim 29

An optical disk according to claim 24, wherein the depth h 0 of each said groove and said recesses is given by: (1/40)λ≦h.sub.0 ≦(9/40)λ, where λ is a wavelength of the laser beam irradiating said optical disk.

Claim 30

An optical disk according to claim 24, wherein the depth h 0 of each said groove and said recesses is preset at about λ/8, respectively.

Claim 31

An optical disk according to claim 24, wherein each of said recesses has a width substantially the same as that of said groove.

Claim 32

An optical disk according to claim 24, wherein each of said guide segments has a width W 0 /2, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective regions of said optical disk.

Claim 33

An optical disk according to claim 24, wherein each of said recesses has a width W 0 /2, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective regions of said optical disk.

Claim 34

An optical disk according to claim 24, wherein each of said recesses has a width smaller than that of said groove.

Claim 35

An optical disk according to claim 31, wherein each of said recesses has a width W 0 /3, where W 0 is a spot diameter of the laser beam irradiating said flat light-reflective regions of said optical disk.

Claim 36

An optical disk according to claim 24, further comprising information pits formed by removing the light reflective layer in predetermined ones of said groove of said guide segments.