1. A signal conversion circuit which is used for a multiple-primary color liquid crystal display device that includes pixels each configured with a red-sub pixel, a green-sub pixel, a blue-sub pixel, and yellow-sub pixel, and that performs color display using four primary colors of red displayed by the red-sub pixel, green displayed by the green-sub pixel, blue displayed by the blue-sub pixel, and yellow displayed by the yellow-sub pixel, and which is configured to convert an input three-primary color video signal into a multiple-primary color video signal corresponding to the four primary colors, wherein
the signal conversion circuit performs signal conversion such that a gray scale level of the yellow-sub pixel is higher than a gray scale level of the green-sub pixel in at least some cases from among cases in which a red gray-scale level r, a green gray-scale level g, and a blue gray-scale level b which are displayed by the three-primary color video signal satisfy a relationship of r>g>b,
each of the red-sub pixel, the green-sub pixel, the blue-sub pixel, and the yellow-sub pixel can perform display 256 gray-scale levels from a gray scale level of 0 to a gray scale level of 255,
each of the red gray-scale level r, the green gray-scale level g, and the blue gray-scale level b, which are displayed by the three-primary color video signal, is equal to or greater than 0 and equal to or less than 255,
at least some cases include a case in which the red gray-scale level r is 255 and the green gray-scale level g is equal to or greater than 1 and equal to or less than 128, and
in a case in which the red gray-scale level r is 255 and the green gray-scale level g is equal to or greater than 1 and equal to or less than 128, The signal conversion is performed such that the gray scale level of the green-sub pixel becomes equal to or less than 80.
2. The signal conversion circuit according to claim 1,
wherein, in the case in which the red gray-scale level r is 255 and the green gray-scale level g is equal to or greater than 1 and equal to or less than 128, the signal conversion is performed such that the gray scale level of the green-sub pixel becomes 0.
3. The signal conversion circuit according to claim 1,
wherein, in at least some cases, the signal conversion circuit performs the signal conversion such that a color, obtained when the pixel is viewed from a front direction when display is performed based on the multiple-primary color video signal, is substantially equal to a color obtained when the pixel is viewed from a 60\xb0 oblique direction.
4. A multiple-primary color liquid crystal display device comprising:
a signal conversion circuit according to claim 1; and
a liquid crystal display panel to which a multiple-primary color video signal generated by the signal conversion circuit is sent.
5. The multiple-primary color liquid crystal display device according to claim 4,
wherein the liquid crystal display panel includes a vertical alignment type liquid crystal layer, and includes the red-sub pixel, the green-sub pixel, the blue-sub pixel, and the yellow-sub pixel, and
wherein, in each of the red-sub pixel, the green-sub pixel, the blue-sub pixel, and the yellow-sub pixel, when a predetermined voltage is applied to the liquid crystal layer, liquid crystal molecules which are included in the liquid crystal layer incline to a plurality of orientations.
6. A signal conversion circuit which is used for a multiple-primary color liquid crystal display device that includes pixels each configured with a red-sub pixel, a green-sub pixel, a blue-sub pixel, and yellow-sub pixel, and that performs color display using four primary colors of red displayed by the red-sub pixel, green displayed by the green-sub pixel, blue displayed by the blue-sub pixel, and yellow displayed by the yellow-sub pixel, and which is configured to convert an input three-primary color video signal into a multiple-primary color video signal corresponding to the four primary colors, wherein
the signal conversion circuit performs signal conversion such that a gray scale level of the yellow-sub pixel is higher than a gray scale level of the green-sub pixel in at least some cases from among cases in which a red gray-scale level r, a green gray-scale level g, and a blue gray-scale level b which are displayed by the three-primary color video signal satisfy a relationship of r>g>b,
each of the red-sub pixel, the green-sub pixel, the blue-sub pixel, and the yellow-sub pixel can perform display 256 gray scale levels from the gray scale level of 0 to the gray scale level of 255,
each of the red gray-scale level r, the green gray-scale level g, and the blue gray-scale level b, which are displayed by the three-primary color video signal, is equal to or greater than 0 and equal to or less than 255,
at least some cases include a case in which the red gray-scale level r is 80 and the green gray-scale level g is equal to or greater than 1 and equal to or less than 40, and
in a case in which the red gray-scale level r is 80 and the green gray-scale level g is equal to or greater than 1 and equal to or less than 40, the signal conversion is performed such that the gray scale level of the green-sub pixel becomes equal to or less than 25.
7. The signal conversion circuit according to claim 6,
wherein, in the case in which the red gray-scale level r is 80 and the green gray-scale level g is equal to or greater than 1 and equal to or less than 40, the signal conversion is performed such that the gray scale level of the green-sub pixel becomes 0.
8. The signal conversion circuit according to claim 6,
wherein, in at least some cases, the signal conversion circuit performs the signal conversion such that a color, obtained when the pixel is viewed from a front direction when display is performed based on the multiple-primary color video signal, is substantially equal to a color obtained when the pixel is viewed from a 60\xb0 oblique direction.
9. A multiple-primary color liquid crystal display device comprising:
a signal conversion circuit according to claim 6; and
a liquid crystal display panel to which a multiple-primary color video signal generated by the signal conversion circuit is sent.
10. The multiple-primary color liquid crystal display device according to claim 9, wherein
the liquid crystal display panel includes a vertical alignment type liquid crystal layer, and includes the red-sub pixel, the green-sub pixel, the blue-sub pixel, and the yellow-sub pixel, and
in each of the red-sub pixel, the green-sub pixel, the blue-sub pixel, and the yellow-sub pixel, when a predetermined voltage is applied to the liquid crystal layer, liquid crystal molecules which are included in the liquid crystal layer incline to a plurality of orientations.
11. A signal conversion circuit which is used for a multiple-primary color liquid crystal display device that includes pixels each configured with a red-sub pixel, a green-sub pixel, a blue-sub pixel, and yellow-sub pixel, and that performs color display using four primary colors of red displayed by the red-sub pixel, green displayed by the green-sub pixel, blue displayed by the blue-sub pixel, and yellow displayed by the yellow-sub pixel, and which is configured to convert an input three-primary color video signal into a multiple-primary color video signal corresponding to the four primary colors, wherein
the signal conversion circuit performs signal conversion such that a gray scale level of the yellow-sub pixel is higher than a gray scale level of the green-sub pixel in at least some cases from among cases in which a red gray-scale level r, a green gray-scale level g, and a blue gray-scale level b which are displayed by the three-primary color video signal satisfy a relationship of r>g>b,
the signal conversion circuit comprising:
a multiple-primary color conversion unit that generates the multiple-primary color video signal based on the input three-primary color video signal; and
a correction unit that corrects a red gray-scale level r1, green gray-scale level g1, signal obtained by the multiple-primary color conversion unit,
the multiple-primary color conversion unit includes a color component extraction unit which extracts a red component, a green component, a blue component, a yellow component, a magenta component, a cyan component, and a white component from the input three-primary color video signal, and
at least some cases in which the signal conversion is performed such that the gray scale level of the yellow-sub pixel is higher than the gray scale level of the green-sub pixel include a case in which the gray scale level y0 of the yellow component extracted by the color component extraction unit is equal to or greater than 1 and equal to or less than 200.
12. The signal conversion circuit according to claim 11, further comprising:
a look-up table that includes a correction value corresponding to a gray scale level y0 of the yellow component which is extracted by the color component extraction unit,
wherein the correction unit corrects the red gray-scale level r1, the green gray-scale level g1, and the yellow gray-scale level y1 with reference to the look-up table.
13. The signal conversion circuit according to claim 11,
wherein, in at least some cases, the signal conversion circuit performs the signal conversion such that a color, obtained when the pixel is viewed from a front direction when display is performed based on the multiple-primary color video signal, is substantially equal to a color obtained when the pixel is viewed from a 60\xb0 oblique direction.
14. A multiple-primary color liquid crystal display device comprising:
a signal conversion circuit according to claim 11; and
a liquid crystal display panel to which a multiple-primary color video signal generated by the signal conversion circuit is sent.
15. The multiple-primary color liquid crystal display device according to claim 14, wherein
the liquid crystal display panel includes a vertical alignment type liquid crystal layer, and includes the red-sub pixel, the green-sub pixel, the blue-sub pixel, and the yellow-sub pixel, and
in each of the red-sub pixel, the green-sub pixel, the blue-sub pixel, and the yellow-sub pixel, when a predetermined voltage is applied to the liquid crystal layer, liquid crystal molecules which are included in the liquid crystal layer incline to a plurality of orientations.
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 pickup device for irradiating an information recording layer of an optical recording medium with a light beam and detecting a reflected light beam reflected on said information recording layer, said optical pickup device comprising:
an objective lens for focusing said light beam onto said information recording layer;
a lens driver for moving the position of said objective lens in response to a drive signal supplied thereto;
a photo-detector having a plurality of light receiving areas, each said light receiving area receiving said reflected light beam and generating an output signal in accordance with the received light beam;
a signal generator for generating a single or a plurality of servo signals from the output signals of said photo-detector;
a drive signal generator for generating a first focus drive signal for activating said lens driver to move said objective lens in a direction closer to said information recording layer, or a second focus drive signal for activating said lens driver to move said objective lens in a direction away from said information recording layer, and supplying said first focus drive signal or said second focus drive signal to said lens driver as said drive signal; and
a controller for executing a switching process for switching the drive signal supplied to said lens driver from said first focus drive signal to said second focus drive signal when the level of said servo signal changes by a predetermined range or more during a period in which said drive signal generator supplies said first focus drive signal to said lens driver.
2. An optical pickup device according to claim 1, wherein said signal generator includes a focus error signal generator for generating a focus error signal whose level varies in accordance with the distance between a current position of said objective lens and a focal position of said objective lens, and outputting said focus error signal as said servo signal.
3. An optical pickup device according to claim 2, further comprising:
a waveform adjuster for determining parameters for adjusting the waveform of said focus error signal during a period in which said drive signal generator supplies said first focus drive signal or said second focus drive signal to said lens driver.
4. An optical pickup device according to claim 2, wherein said controller executes said switching process after a positive peak and a negative peak are detected in said focus error signal.
5. An optical pickup device according to claim 2, further comprising:
a first level comparator for comparing a threshold set between a positive peak and a negative peak of said focus error signal with the level of said focus error signal,
wherein said controller determines, based on a result of the comparison by said first level comparator, whether or not the level of said focus error signal changes by said predetermined range or more in said switching process.
6. An optical pickup device according to claim 5, further comprising a waveform adjuster which includes a peak detector for detecting a positive peak value and a negative peak value of said focus error signal; and a calculator for calculating parameters, using said positive peak value and negative peak value, for adjusting the waveform of said focus error signal during a period in which said drive signal generator supplies said first focus drive signal or said second focus drive signal to said lens driver.
7. An optical pickup device according to claim 6, wherein said calculator calculates an offset value as one of said parameters for said focus error signal using a sum of said positive peak value and said negative peak value, and calculates a gain coefficient as one of said parameters for said focus error signal using an inverse of a difference between said positive peak value and said negative peak value.
8. An optical pickup device according to claim 6, wherein:
said peak detector detects a first set of said positive peak value and said negative peak value of said focus error signal generated during a period in which said first focus drive signal is supplied to said lens driver, and detects a second set of said positive peak value and said negative peak value of said focus error signal generated during a period in which said second focus drive signal is supplied to said lens driver, and
said calculator calculates said parameters using said first and second sets.
9. An optical pickup device according to claim 5, further comprising:
a second level comparator for comparing the level of said focus error signal with a threshold,
wherein said threshold is set at a value between a positive peak value and a negative peak value of said focus error signal and closer to said negative peak value than said positive peak value, and said peak detector detects said negative peak value based on a result of the comparison by said second level comparator during a period in which the level of said focus error signal is lower than said threshold.
10. An optical pickup device according to claim 5, further comprising:
a third level comparator for comparing the level of said focus error signal with a threshold,
wherein said threshold is set at a value between a positive peak value and a negative peak value of said focus error signal and closer to said positive peak value than said negative peak value, and said peak detector detects said positive peak value based on a result of the comparison by said third level comparator during a period in which the level of said focus error signal is equal to or higher than said threshold.
11. An optical pickup according to claim 1, wherein:
said controller executes first said switching process for switching the drive signal applied to said lens driver from said first focus drive signal to said second focus drive signal, executes a second switching process for switching the drive signal from said second focus drive signal to said first focus drive signal after the lapse of a predetermined time from the execution of first said switching process, and executes a third switching process for switching the drive signal from said first focus drive signal to said focus error signal after said second switching process.
12. An optical pickup device according to claim 11, further comprising a sum signal generator for adding output signals from said photo-detector to generate a sum signal,
wherein said controller switches the drive signal supplied to said lens driver from said second focus drive signal to said first focus drive signal when the level of said sum signal changes by a predetermined range or more in said second switching process.
13. An optical pickup according to claim 12, further comprising:
a fourth level comparator for comparing the level of said sum signal with a threshold,
wherein said controller determines, based on a result of the comparison by said fourth level comparator, whether or not the level of said sum signal changes by said predetermined range or more in said second switching process.
14. An optical pickup device according to claim 11, wherein:
said controller switches the drive signal supplied to said lens driver from said second focus drive signal to said focus error signal when the level of said focus error signal changes by a predetermined range or more in said third switching process.
15. An optical pickup device according to claim 14, further comprising:
a fifth level comparator for comparing the level of said focus error signal with a predetermined threshold,
wherein said controller determines, based on a result of the comparison by said fifth level comparator, whether or not the level of said focus error signal changes by said predetermined range or more in said third switching process.
16. An optical pickup according to claim 1, wherein:
said controller executes second switching process for switching the drive signal from said second focus drive signal to said focus error signal when the level of said focus error signal changes by a predetermined range or more after executing first said switching process for switching the drive signal supplied to said lens driver from said first focus drive signal to said second focus drive signal.
17. An optical pickup according to claim 16, further comprising:
a sixth level comparator for comparing the level of said focus error signal with a predetermined threshold,
wherein said controller determines, based on a result of the comparison by said sixth level comparator, whether or not the level of said focus error signal changes by said predetermined range or more.
18. An optical pickup according to claim 1, wherein said signal generator includes a sum signal generator for adding the output signals of said photo-detector to generate a sum signal, and outputting said sum signal as said servo signal.
19. An optical pickup according to claim 18, wherein said controller executes said switching process after a positive peak of said sum signal is detected.
20. An optical pickup according to claim 18, further comprising:
a seventh level comparator for comparing a threshold set between a positive peak value and a negative peak value of said sum signal with the level of said sum signal,
wherein said peak detector detects said positive peak value and said negative peak value of said focus error signal based on the result of the detection by said seventh level comparator during a period in which the level of said sum signal is equal to or higher than said threshold.
21. An optical pickup according to claim 18, further comprising:
an eighth level comparator for comparing a threshold set between a positive peak value and a negative peak value of said sum signal with the level of said sum signal,
wherein said controller determines, based on a result of the comparison by said eighth level comparator, whether or not the level of said sum signal changes by said predetermined range or more.
22. An optical pickup device according to claim 18, further comprising:
a waveform adjuster for determining parameters for adjusting the waveform of said sum signal during a period in which said drive signal generator supplies said first focus drive signal or said second focus drive signal to said lens driver.
23. An optical pickup device according to claim 22, wherein said waveform adjuster includes a peak detector for detecting said positive peak and said negative peak of said sum signal, and a calculator for calculating said parameters using said positive peak value and negative peak value.
24. An optical pickup device according to claim 23, wherein:
said calculator calculates an offset value of said sum signal as one of said parameters using a sum of said positive peak value and said negative peak value, and calculates a gain coefficient for said sum signal as one of said parameters using an inverse of a difference between said positive peak value and said negative peak value.
25. An optical pickup device according to claim 5, wherein:
said optical recording medium includes two of said information recording layers, and
said threshold is set to be equal to or larger than a minimum value of said focus error signal corresponding to one target layer of said information recording layers, and to be less than a minimum value of said focus error signal corresponding to the other layer of said information recording layers.
26. An optical pickup device according to claim 5, wherein:
said optical recording medium includes two of said information recording layers, and
said threshold is set to be equal to or lower than a positive peak value of said focus error signal corresponding to one target layer of said information recording layers, and to be larger than a positive peak value of said focus error signal corresponding to the other layer of said information recording layers.
27. An optical pickup device according to claim 5, further comprising:
a sum signal generator for adding the output signals of said photo-detector to generate a sum signal,
wherein said threshold is set to be variable over time in response to the level of the sum signal generated by adding the output signals of said photo-detector.
28. An optical pickup device according to claim 27, wherein said threshold has a distribution proportional to a level distribution of said sum signal.
29. An apparatus for reading data from an optical storage medium, comprising:
an optical pickup device for irradiating an information recording layer of an optical recording medium with a light beam and detecting a reflected light beam reflected on said information recording layer, said optical pickup device including:
an objective lens for focusing said light beam onto said information recording layer;
a lens driver for moving the position of said objective lens in response to a drive signal supplied thereto;
a photo-detector having a plurality of light receiving areas, each said light receiving area receiving said reflected light beam and generating an output signal in accordance with the received light beam;
a signal generator for generating a single or a plurality of servo signals from the output signals of said photo-detector;
a drive signal generator for generating a first focus drive signal for activating said lens driver to move said objective lens in a direction closer to said information recording layer, or a second focus drive signal for activating said lens driver to move said objective lens in a direction away from said information recording layer, and supplying said first focus drive signal or said second focus drive signal to said lens driver as said drive signal; and
a controller for executing a switching process for switching the drive signal supplied to said lens driver from said first focus drive signal to said second focus drive signal when the level of said servo signal changes by a predetermined range or more during a period in which said drive signal generator supplies said first focus drive signal to said lens driver; and
a decoder for decoding said reproduced signal output from said optical pickup device.