JPS6083225A - High-density code - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates generally to optical recording devices, and more particularly to codes for recording data on a source medium.

[Conventional technology]

In high-density optical recording, it is often desirable to pre-record a tarok or pilot signal on the source medium. This signal is read by the optical system when the data is read. To read this prerecorded pilot signal or clock, data must be recorded such that a null appears in the frequency spectrum upon reading the data. The clock frequency is chosen to match the null in frequency of the data.

This kind of code that generates a null in the frequency spectrum is the so-called quad phase (quaaphas).
e) There is a code. In this gradient sign, two pits of a binary code are encoded as one symbol. In optical recording, these two bits are encoded by writing the hole corresponding to the bit pattern in the first half of the symbol, inverting the bit pattern in the second half of the symbol, and writing the hole corresponding to the one in the second half of the symbol. Ru. Therefore, each symbol is 411.7! ] occupies symbol position 2. binary number 1
0 means cutting 2 holes at symbol positions 1 and 2 and 2 spaces at symbol positions 4 and 7. For binary number 01, symbol position 1 has a hole, symbol positions 2 and 6 have no holes, and symbol position 4 has a hole. The binary number 10 has 2 holes in positions 2 and 6, and 1 in position 1.
and 4 have no holes, and the binary number 11 is at positions 1 and 2.
has hole 7 in position 4 and no hole.

Quad-phase coding uses frequency F corresponding to 14 frequencies of symbol position it. Create a null Z within the data frequency spectrum. This frequency corresponds to the frequency of the binary data. That is, four symbol positions correspond to two bits of binary data.

For high-density optical recording, it is desirable to place the symbol positions 7 close together such that the hole size, ie, its diameter, is larger than one symbol position. This means that
Obviously, when reading and decoding a symbol, the problem arises that the signal of the symbol spreads to adjacent symbol positions.

This problem is exaggerated by the laser read beam optics commonly used in optical recording systems. These beam spots are not sharply defined beams, but have the shape of a Gaussian curve with a power half-width 7 equal to g, the diameter of the hole created when writing with that spot. For a plurality of holes or a group of holes, the half-power width of the readout signal corresponds to the diameter of the holes.

Therefore, the read signal power is considered to be extended beyond the top diameter of the hole.

These two problems, namely symbol position spacing and read signal overlap and hole diameter, are combined to
Limit the bit density in light-year records.

There are a large number of solid block codes that generate nulls w, -r in the frequency spectrum. However, conventional techniques have not provided a methodology for detecting symbols that measure maximum recording density within an optical recording environment.

[Summary of the invention]

The present invention includes maintaining a predetermined spacing between monoholes, or between monoholes and poles, or between groups of holes, within a fixed block code having symbols that include at least two balls. By having symbols with more symbol positions and more holes, it is possible to encode with more bits per symbol. By maintaining the spacing between monoholes, the minimum Furthermore, symbols can be decoded correctly.As a result, more bits can be recorded in a smaller area.

The spacing between monoholes, etc. must be a multiple of the symbol position. Applicants therefore specify at least two symbol positions as the minimum spacing. That is, it is set as D-2 (or higher). The choice of D=2, D=3, D=4, etc. depends on the characteristics of the particular optical recording environment.

In general, if the specific gravity of the expected hole diameter is 1-1 for the numeral size, D must also be thick.
.

In a code family that has nulls in its frequency spectrum to allow the use of prerecorded clocks, the number of holes in a symbol must be a multiple of 20, or 2.4.6.8. The inventor has determined that the diameter of the laser bot is approximately 0.
．． 8 microns, the following pre-clock compatible codes allow maximum bit densities in optical recording of less than 8 bits for pole diameters less than and greater than 1.45 microns, respectively. Decided.

The first code is a 4/]5 code and the second is a 6/'18 code. The first code essentially consists of 155 position symbols and has four hole numbers with the following content: There must be at least 2 empty symbol positions between holes or groups of holes. Historically, there must be 155 position holes and 4 holes in a row within a symbol or adjacent to the removed symbol boundary. It must never contain a pattern with 6 holes 7 in a row. The second code consists of 188 position symbols containing 6 holes with the following content 2: at least 6 spaces between holes or groups of holes. There must be a position.Furthermore, the positions 17 and 18 are
Holes and patterns with 6 and 5 holes in a row or 4 holes in a row in the first 4 positions to be removed must never be included.

The requirement to specify a limit on the number of holes in operation is
Reduces the load on laser diodes commonly used in optical recording systems.

[Embodiments of the invention]

In multiple optical recording systems, the encoded seven symbols represent binary data. In Glock codes with a fixed number of holes, traditionally the signal received from the valley symbol position and the signal received from each of the other symbol positions are The hole position is determined by comparing N high signals and selecting N high signals as the hole position.

(N is the predetermined value of the number of holes in a symbol.) For example, if a symbol has 4 positions, and 2 positions must contain holes, the conventional The optical reader compares the power of the signal associated with the hole at each of the four positions and selects the two higher power positions as the positions where the hole is located.

The horizontal axis in FIG. 1 indicates the symbol pattern 01010010Y written on the original medium. Here, 1 corresponds to a hole and 0 corresponds to a space. In this regard, spaces are shown as protrusions on the horizontal axis and holes are shown as recesses on the horizontal axis. Show one symbol across these eight positions. The vertical axis of FIG. 1 indicates the strength 2 of the signal generated by the holes in the conventional optical reading optics and electronic system.

(If the signal is observed in reflection, the signal caused by the hole will actually be the inverse of the power of the reflected beam, whereas the beam from one side of the disk will be ], the signal is a function proportional to the received laser power.) The dotted curve shown in the figure is the strength of the read signal associated with each of the holes. The shape of these curves is approximately that of a square, and the half-power width of the signal approximately corresponds to the hole diameter. In this figure, the hole diameter is 0.9 microns, and the width of the symbol positions, ie, the distance between symbol centers, is 0.6 microns. The solid lines in the figure indicate the sum of 2 signals caused by adjacent holes.

The figure shows that at no point does the sum of the signals produced by a hole or adjacent holes reach such a level that the peaks produced by the holes themselves are indistinguishable. The symbol pattern shown in FIG. 1 can be read correctly by the optical system because it can correctly identify the beaks 7 associated with holes and also determine the valleys associated with spaces.

However, changes in the sensitivity of the medium and changes in the optical recording system (light intensity, beam aberration) lead to variations in hole diameter. Occasionally, holes with a larger diameter are folded in. For example, in FIG. 2, the hole diameter is 1.25 microns. Similar to FIG. 1, the same symbol pattern RO 101DO10'Y is shown along the horizontal axis. Again, the dotted line indicates the signal generated by a hole, and the solid line indicates the sum of the signals generated by adjacent holes. Looking at this figure, it can be seen that there is a very slight slack in the signal strength between the holes in the 101 pattern. When determining whether this space is a hole or a space, a conventional analog comparison system would incorrectly determine that this space is a hole (not a hole). , only identifies three holes in the symbol, so the last hole in the diagram may be read as a space.

The first two figures show a symbol pattern produced by a single isolated hole, a pattern known as a monohole. Figure 6 shows the hole signal pattern generated by two holes written in one row.
The signal pattern shown in Figure 3 along the phase axis is 0110
It is 1001. The hole diameter is 1.25 microns and the symbol spacing is 0.6 microns. 2
When holes are written adjacent to a hole, they overlap and look like one large, long pole as shown in the figure. This large, long hole produces a signal of somewhat lower intensity than the signal produced by a single hole, as shown in the figure. The signal generated by a group of two holes is compared with the signal generated by two subsequent monoholes.

In this figure, the dotted line indicates the signal 2 generated by the hole itself. The conventional monohole pattern has a Gaussian curve in shape, but the signal due to the 2 ff< hole has Gaussian edges and a flat top. The solid line shows the total signal from nearby holes.

If the device detects the symbol position *V using four high signals, the signal strength generated by the hole pattern 101 at these positions at positions 2, 6, 4, and 5, including the spaces, would be equal to all at position 2.6 since it is higher than the signal produced by the monohole at position 8.
．． Holes at 4, and 5, and spaces at other positions will be falsely detected.

In FIG. 4, the symbol pattern 01100 is shown along the horizontal axis.
1 [10 beg. In this N, the hole diameter is 1.25 microns and the symbol position distance is 0.6 microns. Since the signal due to the double hole and the signal due to the subsequent monohole do not converge in this space to a signal that is roughly equal to or higher than the signal produced by the monohole itself, the reader uses six Hole position 2 can be decoded correctly. Correct decoding is possible even when the signal produced by a double hole is greater in strength than the signal produced by a subsequent monohole and overlaps with significant signal power six positions apart.

The above process can also be extended to groups of six holes in a row. However, the signal power generated by the six holes in one row is much larger than the signal power generated by two holes in one row.Referring again to FIG. The pattern produced by the one with holes in the first six positions is similar to the pattern shown, and the reader has two holes made only in positions 2 and 6 of the symbol. 1.2.3
, and spaces in positions 4 and 5, with holes in positions 4 and 5.

As shown in FIGS. 6 and 4, at least one nitrogen location is required between adjacent nodes. Otherwise, adjacent symbols with intervening patterns 11 D 1 and 1011 Y would be identified as holes due to lack of space. These patterns also occur when there is an extra position between the non-poles, and whether the signal strength of the hole or not exists at this extra position is determined by the position where it is possible to have hole 2 in the comparison building. It is irrelevant because it can be included as υ/dot of 1.

An analysis of Figures 1 to 4 has shown that the presence of two spaces between poles and between hole groups enables correct symbol decoding.

When the size of the hole diameter increases relative to the size of the symbol position, the same reasoning applies to having three spaces between holes or rows of holes and at least two empty positions at symbol boundaries. is shown to be even more advantageous.

In determining the code that yields the maximum bit density, it is desirable to examine only codes that encode powers of two bits, ie, 2 bits, 4 bits, 8 bits, 16 bits, etc. For example, a cut-phase code encodes 2 bits and has 4 symbol positions and a binary hole in the symbol. so-called two out ofei
ght position code (TIF) is
The symbol has fft'Y in the 8th position, and the information is encoded in 4 bits Z. Generally, to encode 2 bits of information in a symbol, the code must have at least 4 different hole patterns.To decode 4 bits of information in a symbol, the code must have at least 4 different hole patterns. It must have 16 different hole patterns. Similarly, to encode 8 bits of information, the code must have at least 256 different patterns.

Up to a certain limit, the more holes in a symbol, the greater the number of possible patterns that the symbol can accommodate. For example, a symbol with 4 positions allows only 4 different patterns, provided there is only one hole per symbol. That is, the hole is at position 1.2
．． 6 or 4. However, if two holes are allowed in the symbol, the six patterns will be 5 (
Becomes Noh. That is 1100 1010 1001 01100101 0
011 (C-S phase code-'C-C1010 and 0
101 patterns are excluded. This allows nulls in the periodic mantissa spectrum, so the pattern at the first two positions is
This is because the condition of being reversed at the position must be followed. It will be appreciated that finding a code that optimizes the number of bits encoded in a given unit space 1)11 is difficult and complex.

FIG. 5 shows the worst-case IOT zeroing for various codes as determined by the inventor. The horizontal axis in FIG. Hole size parameter (/
Bear) Show the result of missing division.

For the laser spot size used, the hole diameter is 0.
．． Below 95 microns, hole size calculations depend on the specific optics and hole size. This calculation formula is complex, not suitable for this analysis, and well known to those skilled in the art. However, when the hole size exceeds 0.95 microns, Σ becomes about % of the hole diameter. Therefore,
The dimension of the horizontal axis has a proportional relationship to the hole diameter,
Generally related to a factor of 5/7 of the hole diameter. Furthermore, the dimension of the horizontal axis is inversely proportional to the symbol position interval. Bit density is constant, i.e. 1.2
The symbol position spacing, which is kept at microns/bit, varies inversely with the number of positions within a symbol. Therefore, the horizontal axis dimension changes in proportion to the number of symbol positions of the splash number.

The vertical axis in the figure shows the ratio of the worst case eye opening to the signal generated in the reader by the monohole. Eye opening is defined as the difference between the amplitude of the signal due to a monohole and the amplitude of the total signal due to adjacent holes measured in one space (FIGS. 1 to 4). Formulas for calculating the eye pattern from a given ladle pattern, hole size, spot size, etc. are well known to those skilled in the art. The worst-case eye can be determined by examining the code pattern 7 in which the distance between holes or groups of holes is the minimum. A smaller eye increases the likelihood of decoding errors due to the unavoidable noise in the system.

Worst case eye pattern for a given code? Having determined the methodology for determining, the inventor further provides the following comparison criteria. The codes being compared must have the same bit density. That is, the number of binary representations encoded into a unit length on the medium must be the same.

As a standard comparative example, 1.2 microns per bit (
bit/1.2 micron). It would make sense to compare the numbers in the same way even though the actual lengths and spacings are different. If there are '2 bits to be encoded, the entire symbol is 2.4 microns long (1.2 microns/bit x 2 bits). If 4-bit encoded, the symbol length is 4.8 microns. For 8 bits, a symbol is only 6 microns long.

All codes shown in FIG. 5 have a bit density of 1.2 microns/bit, and the half power width of the read spot is approximately 0.2 microns/bit.
It is 8 microns. These all have a null 7 in the frequency spectrum. The first solid line in the figure shows the worst-case eye opening for the D=1 code. Here,
D-1 means that at least one symbol position exists between monoholes, between monoholes and hole groups, or preferably between hole groups. The second solid line is the worst case zeroing of the sign for D=2. The sixth solid line is for D=3. Moreover, the dotted line connects the optimal 8-bit codes for each D class. Eye openings were determined for the following hole diameter sizes: (110,95 microns t2N, 25 microns (311,4,5 microns). The TOON code shown with a small circle (0) is the so-called 2 out
It is of 9 code. This is explained previously 2
Adding the 9th empty position to out of 3 code (TOEF) makes them the same. (TOON code and TO
EF code encodes 4 bits '1''.)T
The OI code is indicated by a square (b). Use an inverted triangle ()7 to show 6 out of 12code. (This code encodes 8 bits.)
f 15code 'l:i indicates. In nikawara, it is encoded in 8 bits. ) 6'0utof18CO in a triangle
Indicates de. (This encodes an 8-pin.
Generate the best eye out of 15 codes. That is, the worst case eye opening is 0.
A 95 micron hole diameter has a monohole amplitude of 0.6, and a 1.25 micron hole diameter has a monohole amplitude of 0.3. On the other hand, other codes produce worse Eike for similar diameters. If the hole is 1.45 microns or larger, t5 out of 18code will produce a better eye. This also produces the best eye with higher bit density for smaller holes.

Figure 5 shows that for a given bit density, in most cases the worst case eye is 4 out of 15.
It shows what you can get with the code. In some cases, 6 out of i8c'oae loads the laser, which may be more desirable. Applicant's code has the potential to achieve the highest binary bit density in optical recording or 8-bit preclock compatible block codes.

Applicant's 4 out of 15 code has a limit of 15 symbol positions that must not always have holes.

By using equal numbers of holes in each odd and even position, nulls must be created in the frequency spectrum to realize a pre-clock system. The number of different patterns possible from these limitations is 441.
becomes. Since the number of required patterns is only 256, some of these 441 patterns are removed. The first to be removed are those that do not add to the restriction of D = 2, that is, those that have at least two spaces between monoholes or between monoholes and hole groups, or between hole groups. Next removed is the pattern that places the highest load Z on the laser diode of a conventional optical recording device.The laser diode of most optical recording devices is Under Azusa's condition, the pattern with 6 holes (1) near the Numboru boundary (in the -row) and the pattern (7) with all 4 holes in the -row are removed. Ru.

Table 1 shows a specific set of 256 patterns that the inventors believe will produce this optimal bit code for laser diode optical recording.

Table 14/15 (a=2) code, pre-clock compatible code 1
2 3 4 5 6 7 8 9 10 a b c
d eO× × × × 1 × × × × 2 : K XXX 3 XX XX 4 xx xx 5 a , X a allo , x x × , 7 XX' A11×××X 12 x × × X 16 A××× 14×××× 15 X -X
x X 19xx X X 20 × × × X 21 × × × ××× 30 X x X X 31 XX X X 32 X X XX 33 X X XX 34 x x X X 35 XX X x x 41 x x x X 42XX XX 43 × X X X 44 × X × X 45 × × × X 46 xx x x 4.7 x x x 52 × × × X XX 65 × × X X 66 X XX 6 7 8 9 10, a b
c d e75 x x x 35 x x x x 86 x x x x 87x xx x 88x X X X X 96 x X X X 97 X X X x 98×X XX 99, 'X xx , 100' 105 × × × 7 106 x X x A107 X X X X 108 x X X A109 x X x x llo × X x A111 X X a, b
c d e113 X X × X 1i4. X, x x x 115 x x x x 116 x x x x 117 x x x x 118 x x x /I × X X X 125 x x x x T)6. XX x X 127 X XX X 128 X X X X 129 7 X x X 130 X X x X 131 X X
c d e132 x x x x 133 x x x x 134 x x x x 135 xx, x x 136 x x x 142 × × × 151 x x
x 'x 152 'X 'X X X 153 x x x x 1b4 X x 161 X × A, 162 x x x X 163 X X X X 164 x x x 5 6 7 8 9 iQ a-b
c d e170 X XX X 171 X x x X 172 X X x X 173 X x X X 174 x x x X 180 x X X X 181 × × × X 182 x x x X 183 x x x X 184 X X × X 185 x x x 9× X XX 190 X x x X 191 X X X X 192 x x x x 19ro X × × XX 200 x x x x 2o1 XX X X 202 X X X X 2O3x x X X 204 c.
d e208X x XX 209 X x X X 210 X x x X 211 X x x X 212 X x x 18× ××× 219 x XX ′ 220 X X X X 221 x ×x x ′)22 8 9 10 a b c
d e227 X × x X 228 X x X X 229 x × X X 230 X × XX 231 x X X X 232 x x x x x 237 x x x x 238 x x x x 259 x x x x 240x xx x 241 x x x x 242 x x x abcde246 X X
X X 247 XX X X 248 x x x X 249 1K XXXX 250 X X X In the of 18 code, there should be no holes in the 17th and 18th positions.

Furthermore, is it necessary to generate nulls in the frequency spectrum? These limitations leave 3136 different possible patterns. If those patterns that do not satisfy the restriction of D=3 are removed from these patterns, 316 patterns remain. Next, patterns with 6 and 5 holes in one row and patterns with 4 holes in the first 4 positions are removed, resulting in the 256 required patterns shown in Table 2. (Due to page size limitations, only 16 of the 18 symbol positions are shown. There are absolutely no holes in the last two positions.

] Table 2 6/18 (Higu → code, pre-clock compatible code 0
XXX xx x lxxx XX X 2xxxx xx x 6 xxx x x x 4x xx x x x llXXX XX X 12×××××× 16XXX × X × 12345678910abcdef i4Xxx × X X 20XX XX N × 21 x x x x ×× 22XX XX ' ゞ23XX XX '' 24XX XX X ゞ25XX X × XX 26××Xx xx 27xx xx xx 28XX 32Xx xxxx Yu 2345267891D a b c d e f3
5 XX X 42X'X XXXX 45 X XX X X × 44XXX XX X 45 X ' x X X X 46X x X X 51 X XX X X X l 2 3 4 5 6 7 8 9 10 a b
c d e f52 × × × × × × 53xx X × XX 54xx XX XX 55XX x × × x 56Xx XXXX 57 × × × × × xxxx 63X xx xx X 64 × × × × × X 65 × × × × × ゞ66 × × × × × X 67 × xx xxx 68 × × × × × One------
−−−−−−−−−− 71 x X XXX X 72x 'xx × xx 76 × × X × × × 74×××× A75x XXX XX 76X XX ×××× 79X X XX × X 8Q X X x XX X 81 × × × × × × 82×' XX XXX 88× N X × × X 89X xxx × × 1 2 3 4 5 6 7 8 9 10 a b
c de f9Qx XXX XX 91X XX xxx 92X X xxxx X X 101 × × × × × × iQ2. xxxx XX 106 × × × × × X 1Q4 × xxx xx 1Q5xxxx '
c d e f109xxx xxx 110×××゛××× 111XXX x xx 112XXX x xx 113xxx X XX 114xxx xx 115xxx xxx 116xxx X X ゞ117xxx xx ゞ118xx xxxx 119xx xxx x 120xx xxx x 121xx xx xx 122xx xx, xx 125xx xx ×x 124xx xx xx 125Xx X X ゝ126xx x xxx 127xx x xxx l 2 3 4 5 6 7 8 9 10 a 'b
c d e f128XX XXXX 129XX X'XX X 130XX xx , , 131XX xx XX 132 × X XX × X 133XX X XXX 134XX × XX 7 XXXX 138 × X x xxx 139Xx XXXX 140XX XX XM 141xx x x xx 142Xx XXXX 143XX xxxx 144X xxxx x 145X xxx x x 146'X xxx x 150x xxx ×x 151x xxx xx 152X XXX XX 15, lSx xx ×xx 154x x xxxx 155x x XXXX 156 x x x x 163 x x x x XX 164 X X X X X X 165 x x x x x x 12345678910abcde f166 x x
x x x X 167 x x x x x x 168 x x x x x x 169 x x x X 174 x x x X ) < X 175 x xx x XX 176 x x x x x X x x XX 182 X X X X XX 183 X X X XX × IB4 x x x x x x 1 2 3 4 5 6 7 8 9 1Q a b
c d e f185 x x x x x x 13 (5x x x x x x 187 x x x x x x 188 x x x x x x x 192 x x , x x x x 193 x x x x x x 194 x x x x x x X 199 x x x x X X 200 X X X X X X 201 X x X X X 206×××××× 207 X X XX X X 2O3x xx X X X 209 X X X X X XX X X 214 X X x x ×x 215 X X xx x X 216 X X X X X x x X 222 X X X X X X 12345 678910abcdef223 X X
X X X X 224 X X X X X X 225 x x x x x X 226 x x x X X X X 231 x x x x X X 232 X X X X XX XX 259 X x x x x X 240 X X x x x X 241 × × × × × X 12345 678910abcdef242 × ×
× × × X 245 x x x x y X 244 x X XX XX 245 x, X 250 x X x x x x 251 x x x x x x 252 X The apparatus is shown in FIG. The laser disk 10 includes a disk of optically reflective material, in which holes are formed by heat to reduce the reflectance on the surface of the disk at the holes. The disk 10 is copied by a copying process.
It typically includes groups (grooves, not shown) made in the base. The depth of the groups is determined according to the clock frequency. After this, the substrate surface is coated with an optically reflective material suitable for recording on that surface in the form of holes according to the invention. The disk 10 is rotated while recording and reading mall line data.

The laser 14 is used for recording and reading data.

In record mode, the radar is operated at higher power than in queue mode. The power is at a level that heats holes in the reflective material of disk 10.

In this respect, the hole writing K can be performed by the laser itself, such as a laser diode, receiving a pulse, or by the beam of a laser, such as in the form of a gas laser, being deflected from the optical disk 10. It's okay. In read mode, the laser operates continuously at lower power, which is not sufficient to change the reflective properties of optical disc 10. This laser is placed under the control of a laser controller 16. control 1
6 controls the power level of the laser, its pulse output, and Haheem deflection. Sent from the write data encoder 18. A data encoder 18 receives binary data to be written on the optical disc 10 and encodes the binary data in accordance with the present invention.
Out of 15 or 6 Out of 18 encoded data and control 1
Send to 6. A radar control 16 controls the radar 14 to write data on the rotating optical disk 10.

In both the re-entry mode and the reading mode, the reading device 20
The reflection of the radar beam from the optical disk 10 is detected.

The device for this detection is conventionally a photodiode, which converts light into an electrical signal. The output of the reading device 20 is
The signal is supplied to a servo device 24, which maintains the position of the laser 14 and reading device 20 relative to the tracks on the optical disk. The output of reader 20 is also sent to data decode 22 and read-after-write verification circuit 26. The read-after-write verification circuit 26
To verify that the data was written correctly on the 0, the data written onto the disk and the data read from the disk are compared during the write. If the data is not correctly populated on disk 10, a rewrite is initiated or an error correction device is used. In read scatter mode, the data given to data decoding is 4 ou
tofi5 code or 6out of 8c
ode is decoded into an 8-bit binary code, which is the original data.

In the preferred embodiment, error correction (not shown) is performed on 8-bit binary data.

In summary, the first code of Applicant's invention includes a symbol having 15 equally spaced positions within the symbol to encode 8° bits of binary data. The holes may be differentiated around the symbol and have a diameter that exceeds the symbol position spacing. Exactly 4 holes and only 4 holes appear within each symbol. For every hole appearing in an even numbered position, a hole appears in an odd numbered position. The opposite also holds true. This creates a null in the frequency spectrum, and the prerecorded clock signal can be read and decoded by other electronic systems, not shown here. There are no holes in these 15 positions. At least two symbol positions appear between monoholes, between a monohole and a group of holes, or between a group of holes.

Although not external to the present invention, the launch value is 441 to 25.
In order to reduce the number to 6, the following restrictions are added. All symbols with four consecutive holes are removed. Positions 1.2 and 6, or 2.3 and 4, or 1
2. All symbols with 6 holes at 16 and 14 are removed.

The code for 6 out of 8 in the application similarly has D=3, and the last two spaces of the name symbol (symbol LL).
It consists of 2 spaces)° in i1. Symbols with 5 or 6 holes in a row and 4 holes in positions 1 to 4 in a row are removed.

A specification of elements of the preferred embodiment is set forth in Claim 6J.

shall not be considered as a limitation to four.

[Brief explanation of the drawing]

Figures 1 to 4 are graphs showing the relationship between the symbol position and the strength of the code detected by the reading optical system of the optical disc ML recording system, and Figure 5 is the worst case eye opening for the monohole amplitude. FIG. 6 is a block diagram of an optical recording device for implementing the preferred embodiment code. Explanation of symbols 10...Laser disc 12...Motor 14.-
・Laser 16...Laser limited edition! Device 18...
Data encoding 20...Reading device 22...Data decoding 24...Servo 26...Actual verification device. Agent Tanzai 99.1 Song I Dinghan) and 1\6 Hoonzonn lawsuit) and buff-/

Claims (1)

Claims: (1) A high-density code, the high-density code for encoding optical recording of binary data including a fixed block code, the high-density code including a fixed block code; : with a symbol having a predetermined number of positions 7; with each singill having a predetermined number of holes greater than 2; with a predetermined position between monoholes, or between a monohole and a group of holes, or between a group of holes. in each symbol having a number of symbol positions of 1, said predetermined (first) number being greater than or equal to 2; and a second predetermined number of empty symbol positions at the boundaries of said symbols; , wherein the predetermined second number is 1 less than the predetermined first number, and each non-pol is equal to or less than the predetermined first number. The high-density code is the fixed block code. (2. In Claim 1, the high-density code is the high-density code for recording and reading coded binary data on an optical recording medium, and the optical recording medium is in a certain state. The optical recording is of a type in which a hole is created in the medium to indicate 1-, and shows a complement state when there is no hole, and a type that further has a null Z in the frequency spectrum when recording or reading. The optical medium may also include a pre-recorded clock number 4j to assist in loading and reading the data, wherein the high-density clock number is 8 in two symbols. said symbol having 15 equally spaced positions within said symbol to encode 7 binary bits of data; the restriction that exactly 4 holes, and only 4 holes, appear in each symbol; and; For each hole appearing in an even numbered position, there is a restriction that a hole appears in an even numbered position; A restriction that said 15 positions never have a hole; Between monoholes, or between a monohole and a group of holes, or between holes. (3) Claim 2 further provides that the four holes are never consecutive. (4) In claim 2, furthermore, the groups of six holes are arranged at positions 1.2 and 6, positions 2. 6, and 4, or positions 12, 16, and 14. (5) In claim 6, the group of three holes further comprises: The cylinder density code has a restriction that it is not recorded in positions 1.2 and 6, positions 2.6 and 4, or positions 12.16 and 14. (6) Claim 1 An optical recording/reading device for recording and reading a density code, comprising: an optical disk device; a device for driving the disk; a laser device for emitting a laser beam onto the disk; a device for controlling the laser beam; a device for optically detecting the laser beam after it hits the disk; a device for encoding data into a predetermined format; The device for controlling the encoder is configured to record the encoded data on the disk by heat-treating holes on the disk according to the predetermined format. a device for encoding, the device for controlling the device being responsive to the device; a device for decoding the encoded data, the device being responsive to the device for detecting laser beam interference; The predetermined format is a two-symbol recording/reading device, wherein the symbol has 15 consecutive positions equally spaced within the symbol, and the symbol position is:
Hole heat treatment can be performed in the optical disc by the laser device at successive positions of the symbol on the disc, each heat treated hole being:
the symbol being each pole having a diameter greater than or equal to the length of the symbol position on the optical disc; each symbol having exactly 4 holes and only 4 holes; 2 at even positions; With each symbol that has two holes at odd-numbered positions; With each symbol that does not have a hole at the 15 positions; Between monoholes, or between a monohole and a hole group, or between a hole group. , in each symbol having at least two positions, a monohole includes a hole at a symbol position that has no hole at an adjacent position, and a hole group includes a hole at a symbol position that has no hole at an adjacent position; The optical recording/reading device includes the predetermined format Z with each symbol being a group. (7) The optical recording/reading device of claim 6, further comprising each symbol having never four consecutive holes. (8) In claim 6, furthermore, 6 recorded at symbol positions 1.2 and 6, non-pol positions 2.6 and 4, or symbol positions 12.16 and 14.
The optical record never has a group of holes/
reading device. (9) Percentage Allowance In claim 7, furthermore, symbol positions 1.2 and 6, symbol positions 2.6 and 4,
Or said optical recording/reading device which never has a group of six holes recorded at symbol positions 12, 13 and 14. (10)% Permissible In claim 1, the cylinder density code is the local density code for recording and reading binary data on an optical recording medium, and the optical recording medium indicates a certain state. Create a hole 2 in the medium for
The optical recording medium is of a type that exhibits a complement state when there is no hole, and further has a null in the frequency spectrum upon recording or reading,
The optical medium may include a pre-recorded clock signal 2 to assist in writing and reading the data, the high density code encoding eight binary bits of data in two symbols. said symbol having 18 equally spaced positions within said symbol in order to; with the restriction that exactly 6 holes and only 6 holes appear in each symbol; for each hole appearing in an even position; , a restriction that holes appear in odd-numbered positions; a restriction that the 17th and 18th positions never have a hole; The high density code with the limitation that 6 positions appear. (11) In claim 10, furthermore, 5
2. Said high-density code with the limitation that 2 or 6 holes are never recorded consecutively. The high-density code according to claim 10, with a limitation that four hole groups are not recorded at positions 1, 2, 6, and 4. 03) The high-density code according to claim 11, having the restriction 2 that four hole groups are not recorded at positions 1, 2, 6, and 4. ■ In the optical recording/reading device for recording and reading high-density codes as set forth in claim 1: an optical disk device; a device for driving the disk; and a device for driving the disk; 1- a laser device; a device for controlling the laser device; a device for optically detecting the laser beam after it collides with the disk; and 2. encoding data into a predetermined format. In the apparatus for recording the encoded data on the disc, the apparatus for controlling the recording apparatus may record the encoded data on the disc by heat treating holes on the disc according to the predetermined format. , the device for encoding, which is the device for controlling the device for encoding; responsive to the device for detecting the laser beam to decode the encoded data; said optical recording/reading apparatus comprising: said predetermined format being two symbols, said symbol having 18 equally spaced consecutive positions in said symbol', said symbol position being , the symbol positions comprising consecutive positions on the disc that can be heat treated holes in the optical disc by the laser device, each heat treated hole having a diameter 7 equal to or greater than the length of the symbol on the optical disc. each symbol being a heat treated hole; each symbol having exactly 6 holes and only 6 holes; each symbol having 6 holes in even positions; 6 holes in odd positions; With each symbol having holes 2; 17th and 1
For each symbol that does not have a hole 2 in the 8th position: between monoholes, or between a monohole and a group of holes, or between a group of holes, for each symbol that has at least 6 symbol positions, a monohole has an adjacent position. The monohole includes a symbol position where no hole exists,
The optical recording/reading device includes the predetermined format Z, wherein each symbol is a group of holes including more than one hole in adjacent positions. (15) The optical recording/reading device according to claim 14, further comprising each hole 7 having never 5 or 6 consecutive holes. (16) The optical recording/reading device according to claim 15, wherein each symbol never has a group of four holes recorded at positions R1, 2, 6, and 4. Q7) The optical recording/reading device according to claim 16, further comprising each symbol having four hole groups recorded at symbol positions 1, 2, 6, and 4.