Abstract: An optical pickup is configured such that light split by a light-splitting element is received by light-receiving elements provided on a light-receiving surface of a light-receiving unit, has on the light-receiving surface of the light-receiving unit quartered light-receiving portions that detect position-adjustment light and configured by equal quartering so as to be arranged in two dimensions, and in which the position of the light-splitting element is adjusted based on the position-adjustment light received by each of the quartered light-receiving portions.

Abstract: An optical pickup includes a plurality of light sources, an objective lens, a diffractive optical element, and a light-detecting unit. The various light sources emit light of wavelengths that are different from each other. The objective lens focuses light on an optical disc. The diffractive optical element includes a diffracting portion and a light-blocking portion. The diffracting portion diffracts return light reflected from a first recording layer of the optical disc where information is being read or written. The light-blocking portion blocks stray light reflected from a second recording layer of the optical disc that is different from the first recording layer. The light-detecting unit receives the diffracted light of the diffractive optical element and generates an output signal to generate a tracking error signal based on this diffracted light. Furthermore, the light-blocking portion includes a plurality of light-blocking patterns which block light of wavelengths that are different from each other.

Abstract: The liquid crystal element includes a pair of transparent substrates, a liquid crystal arranged between the substrates, a diffraction pattern including concentric diffraction electrodes formed on one substrate, and a phase shift pattern including concentric phase shift electrodes formed on the other substrate. The diffraction pattern includes a first region being of a constant range in a radial direction from a center and having a wide electrode interval, a second region being arranged on the outer side of the first region and having a narrow electrode interval, and a third region being arranged on the outer side of the second region and including a single diffraction electrode. An additional electrode facing the phase shift electrode is arranged in a gap between the diffraction electrodes in the first region.

Abstract: An optical pickup apparatus includes a plurality of laser light sources, a single objective lens, and a beam shaping mirror. The beam shaping mirror causes each of the laser beams to be incident on a transmission surface, reflects the beam from a reflection surface being unparallel to the transmission surface and causes the beam to emerge from the transmission surface, thereby to convert a light intensity distribution of the beam of each of the wavelengths from an elliptic shape into a circular shape. The beam shaping mirror is made of a liquid crystal, which forms the transmission surface and the reflection surface, and is electrically driven so that a refractive index of the liquid crystal may be held constant irrespective of the wavelengths of the beams each of which enters the beam shaping mirror.

Abstract: The liquid crystal element includes a pair of transparent substrates, a liquid crystal arranged between the substrates, a diffraction pattern including concentric diffraction electrodes formed on one substrate, and a phase shift pattern including concentric phase shift electrodes formed on the other substrate. The diffraction pattern includes a first region being of a constant range in a radial direction from a center and having a wide electrode interval, a second region being arranged on the outer side of the first region and having a narrow electrode interval, and a third region being arranged on the outer side of the second region and including a single diffraction electrode. An additional electrode facing the phase shift electrode is arranged in a gap between the diffraction electrodes in the first region.

Abstract: The present invention aims to correct the spherical aberration and ensure the working distance and furthermore to obtain satisfactory recording and reproducing property by shaping the optical spot formed on the disc surface. A liquid crystal element for correcting spherical aberration includes diffraction electrodes for converting the light beam to a divergent light when reproducing a CD, and phase shift electrodes for providing a phase difference to the light beam when reproducing a BD. When reproducing a BD, voltage is applied to the diffraction electrodes as well as the phase shift electrodes to diverge the light beam and lower the light intensity of the central portion, thereby shaping the optical spot formed on the disc.

Abstract: An optical pickup device includes a beam shaping mirror. The mirror has a first optical surface on which a wavelength selection film is formed and a second optical surface on which a diffraction grating is formed. The wavelength selection film transmits a first laser beam and reflects a second laser beam. Light intensity distribution of the first laser beam is converted from an elliptic shape to a circular shape by reflecting the first laser beam transmitted by the wavelength selection film and input to the beam shaping mirror by the diffraction grating, then transmitting it by the wavelength selection film and outputting it from the beam shaping mirror. The diffraction grating diffracts the first laser beam in order that directions of the first and second laser beams which are output from the beam shaping mirror become the same.

Abstract: An optical pickup device includes a beam shaping mirror. The mirror has a first optical surface on which a wavelength selection film and a diffraction grating are formed, and a second optical surface that is composed of a reflecting surface. The wavelength selection film passes a first laser beam and reflects a second laser beam. A light intensity distribution of the first laser beam is converted from an elliptic shape to a circular shape by operation in which the first laser beam which passes the wavelength selection film and is input to the beam shaping mirror, is reflected on the second optical surface, passes the wavelength selection film and is output from the mirror. The second laser beam is diverged by the diffraction grating. Directions of the first and second laser beams which are output from the mirror are made the same by diffraction of the second laser beam.

Abstract: An optical pickup device in which light via a beam shaping mirror is input to an objective lens and the light is directed to an optical disc, includes a collimator lens which changes the light input to the beam shaping mirror into infinite system light and the beam shaping mirror includes a diffraction grating which changes the infinite system light into finite system light.

Abstract: An optical pickup device for reducing comma aberration, spherical aberration, and astigmatism while entering a beam light having an ideal intensity distribution to the objective lens is provided. In an optical pickup device for emitting beam lights having different wavelengths from light sources, transmitting the beam lights through a common collimator lens and an objective lens and irradiating the beam lights onto an optical disc, one of the beam lights is converted to an infinite light and exit from the collimator lens, and the other beam light is converted to a finite light and exit from the collimator.

Abstract: An optical pickup apparatus includes a plurality of laser light sources, a single objective lens, and a beam shaping mirror. The beam shaping mirror causes each of the laser beams to be incident on a transmission surface, reflects the beam from a reflection surface being unparallel to the transmission surface and causes the beam to emerge from the transmission surface, thereby to convert a light intensity distribution of the beam of each of the wavelengths from an elliptic shape into a circular shape. The beam shaping mirror is made of a liquid crystal, which forms the transmission surface and the reflection surface, and is electrically driven so that a refractive index of the liquid crystal may be held constant irrespective of the wavelengths of the beams each of which enters the beam shaping mirror.

Abstract: A spherical aberration correcting device includes liquid crystal, a first transparent electrode and a second transparent electrode. The first transparent electrode works as a common electrode. The second transparent electrode has different electrode patterns for a first region and a second region that surrounds the first region. The electrode pattern in the first region is a concentric interference pattern. The electrode pattern in the second region has a plurality of concentric regions. The plurality of concentric regions can be supplied potentials independently.

Abstract: An optical pickup device includes at least a laser light source an objective lens, a photo detector, and a spherical-aberration compensating element. The spherical-aberration compensating element is configured so that a holographic polymer-dispersed liquid crystal formed by dispersing liquid crystal molecules in a polymer resin in a predetermined pattern is interposed between a pair of transparent substrates facing each other through transparent electrodes. Additionally, at least two or more spherical-aberration compensating elements are provided on an optical axis closer to the laser light source than the objective lens.

Abstract: Optical pickup device equipped with liquid crystal diffraction element is provided with liquid crystal diffraction element control portion, which includes detecting portions for detecting light quantities of 0 order light and 1st order light from signal of photo detector for receiving the 0 order light and 1st order light generated by liquid crystal diffraction element, processing portion for determining light quantity ratio of 0 order light to 1st order light from light quantities obtained by detecting portions and for deciding whether or not difference between light quantity ratio and prescribed light quantity ratio is within predetermined range and for determining correction value of voltage to be applied to transparent electrodes if difference is not within predetermined range, and voltage control portion for controlling the voltage value to be applied to transparent electrodes based on process result of processing portion.

Abstract: A liquid crystal element includes a first transparent electrode (14) and a second transparent electrode (15), which have different concentric split areas (14a-14d) and (15a-15e), each of the split areas (14a-14d) of the first transparent electrode (14) faces two areas out of the split areas (15a-15e) of the second transparent electrode (15), and on the other hand, each of the split area (15a) and the split area (15e) out of the split areas (15a-15e) of the second transparent electrode (15) faces only one area, i.e., the split area (14a) and (14d) of the first transparent electrode (14), and each of the other split areas (15b-15d) faces two areas out of the split areas (14a-14d) of the first transparent electrode (14).