What is claimed is:
1. A layout method for an LSI having a plurality of cells, comprising:
a cell arrangement processing step of performing automated arrangement of cells on a chip on the basis of a netlist, which has a plurality of cells and connection data therefor, and cell timing conditions data;
a global wiring processing step of generating wiring connecting said cells with alleviating conditions for short circuits between wiring;
a timing optimization processing step of optimizing a timing of the cells in accordance with the signal propagation time of the wiring connecting said automatically arranged cells;
a congestion rate analysis processing step of seeking a congestion rate of said wiring, and detecting regions for which the congestion rate is higher than a reference level;
a cell rearrangement processing step of performing rearrangement processing of said cells in small regions for which the congestion rate is higher than the reference level, said chip being divided into a plurality of small regions; and
a detailed wiring processing step of generating wiring connecting the cells, after said cell rearrangement processing, such that short circuits between wiring are forbidden.
2. The LSI layout method according to claim 1, further comprising a clock tree generation step of generating a clock tree with respect to the arranged cells, after said cell arrangement processing and before said cell rearrangement processing.
3. The LSI layout method according to claim 2, wherein the clock tree generation step is executed once again after said cell rearrangement processing.
4. The LSI layout method according to claim 1, wherein said cell rearrangement processing step includes a processing which enlarges gaps between a plurality of neighboring cells or cell rows.
5. The LSI layout method according to claim 1, wherein said cell rearrangement processing step includes a processing which shifts a plurality of neighboring cells in at least one of a leftward or rightward direction, upward or downward direction, an oblique direction, and a rotational direction.
6. The LSI layout method according to claim 1, wherein said cell rearrangement processing step includes a processing which inverts the orientation of cells.
7. The LSI layout method according to claim 1, wherein said cell rearrangement processing step includes a processing which substitutes cells with different cells whose logic characteristics are the same and whose connection pin positions are different.
8. The LSI layout method according to claim 1, wherein said cell rearrangement processing step is performed while maintaining timing relationships of cells.
9. The LSI layout method according to claim 1, wherein said wiring congestion rate analysis step determines said congestion rate in accordance with at least one of the total surface area of cells in said small regions, the total number of cell connection pins, the total number of connection wires, and the total number of through wires.
10. The LSI layout method according to claim 1, wherein said wiring congestion rate analysis step determines said congestion rate in accordance with a value produced by dividing the total number of connection wires in said small regions by the total number of cell connection pins.
11. The LSI layout method according to claim 1, wherein said timing optimization processing involves at least one of: substitution of cells with different cells which differ with respect to at least one of cell output drive capability, cell delay time, and cell input load capacitance; insertion of a buffer in wiring connecting cells; and elimination of a buffer from wiring connecting cells.
12. The LSI layout method according to claim 1, wherein, in a case in which, after said cell rearrangement processing, wiring congestion rate analysis is performed once again and the reference level is not exceeded by the congestion rate, said detailed wiring processing is performed.
13. The LSI layout method according to claim 12, wherein, in a case in which the result of the congestion rate analysis after said cell rearrangement processing indicates the existence of regions for which the congestion rate exceeds the reference level, the size of said small regions is increased to perform the cell rearrangement processing once again.
14. An LSI layout system for performing layout of an LSI having a plurality of cells, comprising:
automated arrangement unit for performing automated arrangement of cells on a chip on the basis of a netlist, which has a plurality of cells and connection data therefor, and cell timing conditions data;
global wiring processing unit for generating wiring connecting said cells with alleviating conditions for short circuits between wiring;
timing optimization processing unit for optimizing a timing of the cells in accordance with the signal propagation time of the wiring connecting said automatically arranged cells;
congestion rate analysis processing unit for seeking a congestion rate of said wiring, and detecting regions for which the congestion rate is higher than a reference level;
cell rearrangement processing unit for performing rearrangement processing of said cells in small regions for which the congestion rate is higher than the reference level, said chip being divided into a plurality of small regions; and
detailed wiring processing unit for generating wiring connecting the cells, after said cell rearrangement processing, such that short circuits between wiring are fobidden.
15. The LSI layout system according to claim 14, further comprising a clock tree generation unit for generating a clock tree with respect to the arranged cells, after said cell arrangement processing and before said cell rearrangement processing.
16. The LSI layout system according to claim 15, wherein the clock tree generation is performed once again after said cell rearrangement processing.
17. The LSI layout system according to claim 16, wherein said cell rearrangement processing unit performs the cell rearrangement processing while maintaining timing relationships of cells.
18. An LSI layout program for making a computer perform layout of an LSI having a plurality of cells, comprising:
an automated cell arrangement program for performing automated arrangement of cells on a chip on the basis of a netlist, which has a plurality of cells and connection data therefor, and cell timing conditions data;
a global wiring processing program for generating wiring connecting said cells with alleviating conditions for short circuits between wiring;
a timing optimization processing program for optimizing timing of the cells in accordance with the signal propagation time of the wiring connecting said automatically arranged cells;
a congestion rate analysis processing program for seeking a congestion rate of said wiring, and detecting regions for which the congestion rate is higher than a reference level;
a cell rearrangement processing program for performing rearrangement processing of said cells in small regions for which the congestion rate is higher than the reference level, said chip being divided into a plurality of small regions; and
a detailed wiring processing program, for generating wiring connecting the cells, after said cell rearrangement processing, such that short circuits between wiring are denied.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An optical head for recording or reproducing information with respect to an information recording surface of a first information recording medium, an information recording surface of a second information recording medium, and an information recording surface of a third information recording medium, the first information recording medium, the second information recording medium, and the third information recording medium having protective substrate thicknesses different from each other, the optical head comprising:
a light source configured to output laser light of a first wavelength \u03bb1, laser light of a second wavelength \u03bb2, and laser light of a third wavelength \u03bb3, the first wavelength \u03bb1, the second wavelength \u03bb2, and the third wavelength \u03bb3 being different from each other; and
an objective lens configured to converge the laser light of the first wavelength \u03bb1, the laser light of the second wavelength \u03bb2, and the laser light of the third wavelength \u03bb3 on the information recording surface of the first information recording medium, the information recording surface of the second information recording medium, and the information recording surface of the third information recording medium, wherein
the first wavelength \u03bb1 satisfies a condition: 390 nm\u2266\u03bb1\u2266430 nm,
the second wavelength \u03bb2 satisfies a condition: 630 nm\u2266\u03bb2\u2266680 nm,
the third wavelength \u03bb3 satisfies a condition: 750 nm\u2266\u03bb3\u2266810 nm,
at least one surface of the objective lens is provided with a diffraction structure having a step for giving an optical path length difference with respect to the laser light to be incident on the objective lens,
the diffraction structure is configured to generate normal diffracted order light which is converged on the information recording surface of the third information recording medium, and unwanted diffracted order light which is collected at a position away from the information recording surface of the third information recording medium, from laser light of the third wavelength \u03bb3 transmitted through the objective lens, and
a distance from a convergent point of the normal diffracted order light, to a virtual collecting point formed by virtual diffracted order light between the convergent point of the normal diffracted order light and a collecting point of the unwanted diffracted order light is twice or more of a pull-in range of a focus error signal to be obtained in recording or reproducing information with respect to the third information recording medium,
a third focus error signal to be detected based on the virtual diffracted order light is generated between a first focus error signal to be detected based on the normal diffracted order light and a second focus error signal to be detected based on the unwanted diffracted order light,
the diffraction structure forms a plurality of virtual collecting points respectively formed by a plurality of virtual diffracted order lights between the convergent point of the normal diffracted order light and the collecting point of the unwanted diffracted order light,
the third focus error signal includes a plurality of third focus error signals to be detected based on the virtual diffracted order light, and
a distance between a zero-cross point of the third focus error signal closest to the first focus error signal, out of the plurality of the third focus error signals, and a zero-cross point of the first focus error signal is twice or more of the pull-in range of the first focus error signal to be obtained in recording or reproducing information with respect to the third information recording medium.
2. The optical head according to claim 1, wherein
an amplitude of at least one of the third focus error signals is larger than an amplitude of the second focus error signal.
3. The optical head according to claim 1, wherein
a distance between a zero-cross point of the third focus error signal having a larger amplitude than an amplitude of the second focus error signal, out of the plurality of the third focus error signals, to the zero-cross point of the first focus error signal is twice or more of the pull-in range of the first focus error signal to be obtained in recording or reproducing information with respect to the third information recording medium.
4. An optical head for recording or reproducing information with respect to an information recording surface of a first information recording medium and an information recording surface of a second information recording medium, the first information recording medium and the second information recording medium having protective substrate thicknesses different from each other, the optical head comprising:
a light source configured to output laser light of a first wavelength \u03bb1 and laser light of a second wavelength \u03bb2, the first wavelength \u03bb1 and the second wavelength \u03bb2 being different from each other; and
an objective lens configured to converge the laser light of the first wavelength \u03bb1 and the laser light of the second wavelength \u03bb2 on the information recording surface of the first information recording medium and the information recording surface of the second information recording medium, wherein
the first wavelength \u03bb1 satisfies a condition: 390 nm\u2266\u03bb1\u2266430 nm,
the second wavelength \u03bb2 satisfies a condition: 630 nm\u2266\u03bb2\u2266680 nm,
at least one surface of the objective lens is provided with a diffraction structure having a step for giving an optical path length difference with respect to the laser light to be incident on the objective lens,
the diffraction structure is configured to generate normal diffracted order light which is converged on the information recording surface of the second information recording medium, and unwanted diffracted order light which is collected at a position away from the information recording surface of the second information recording medium, from laser light of the second wavelength \u03bb2 transmitted through the objective lens, and
a distance from a convergent point of the normal diffracted order light, to a virtual collecting point formed by virtual diffracted order light between the convergent point of the normal diffracted order light and a collecting point of the unwanted diffracted order light is twice or more of a pull-in range of a focus error signal to be obtained in recording or reproducing information with respect to the second information recording medium,
a third focus error signal to be detected based on the virtual diffracted order light is generated between a first focus error signal to be detected based on the normal diffracted order light and a second focus error signal to be detected based on the unwanted diffracted order light,
the diffraction structure forms a plurality of virtual collecting points respectively formed by a plurality of virtual diffracted order lights between the convergent point of the normal diffracted order light and the collecting point of the unwanted diffracted order light,
the third focus error signal includes a plurality of third focus error signals to be detected based on the virtual diffracted order light, and
a distance between a zero-cross point of the third focus error signal closest to the first focus error signal, out of the plurality of the third focus error signals, and a zero-cross point of the first focus error signal is twice or more of the pull-in range of the first focus error signal to be obtained in recording or reproducing information with respect to the third information recording medium.
5. An objective lens for converging laser light of a first wavelength \u03bb1, laser light of a second wavelength \u03bb2, and laser light of a third wavelength \u03bb3 on an information recording surface of a first information recording medium, an information recording surface of a second information recording medium, and an information recording surface of a third information recording medium, the first information recording medium, the second information recording medium, and the third information recording medium having protective substrate thicknesses different from each other, and the first wavelength \u03bb1, the second wavelength \u03bb2, and the third wavelength \u03bb3 being different from each other, wherein
at least one surface of the objective lens is provided with a diffraction structure having a step for giving an optical path length difference with respect to the laser light to be incident on the objective lens,
the first wavelength \u03bb1 satisfies a condition: 390 nm\u2266\u03bb1\u2266430 nm,
the second wavelength \u03bb2 satisfies a condition: 630 nm\u2266\u03bb2\u2266680 nm,
the third wavelength \u03bb3 satisfies a condition: 750 nm\u2266\u03bb3\u2266810 nm,
the diffraction structure is configured to generate normal diffracted order light which is converged on the information recording surface of the third information recording medium, and unwanted diffracted order light which is collected at a position away from the information recording surface of the third information recording medium, from laser light of the third wavelength \u03bb3, and
the diffraction structure gives a lens effect such that a distance from a convergent point of the normal diffracted order light, to a virtual collecting point formed by virtual diffracted order light between the convergent point of the normal diffracted order light and a collecting point of the unwanted diffracted order light is twice or more of a pull-in range of a focus error signal to be obtained in recording or reproducing information with respect to the third information recording medium,
a third focus error signal to be detected based on the virtual diffracted order light is generated between a first focus error signal to be detected based on the normal diffracted order light and a second focus error signal to be detected based on the unwanted diffracted order light,
the diffraction structure forms a plurality of virtual collecting points respectively formed by a plurality of virtual diffracted order lights between the convergent point of the normal diffracted order light and the collecting point of the unwanted diffracted order light,
the third focus error signal includes a plurality of third focus error signals to be detected based on the virtual diffracted order light, and
the diffraction structure gives a lens effect such that a distance between a zero-cross point of the third focus error signal closest to the first focus error signal, out of the plurality of the third focus error signals, and a zero-cross point of the first focus error signal is twice or more of the pull-in range of the first focus error signal to be obtained in recording or reproducing information with respect to the third information recording medium.
6. An optical disc device comprising:
the optical head of claim 1;
a motor configured to drive and rotate an information recording medium; and
a controller configured to control the optical head and the motor.
7. A computer comprising:
the optical disc device of claim 6;
an input unit configured to input information;
an arithmetic unit configured to compute based on information reproduced from the optical disc device andor information input from the input unit; and
an output unit configured to output the information reproduced from the optical disc device, the information input from the input unit, andor a result of computation by the arithmetic unit.
8. An optical disc player comprising:
the optical disc device of claim 6; and
a decoder configured to convert an information signal to be obtained from the optical disc device into image information.
9. An optical disc recorder comprising:
the optical disc device of claim 6; and
an encoder configured to convert image information into an information signal to be recorded by the optical disc device.