Abstract: An embodiment resin composition for shielding electromagnetic waves, based on a total weight of the resin composition, includes 20 to 80 wt % of thermoplastic resin, 1 to 50 wt % of a conductive filler, and 0.1 to 30 wt % of an additive.

Abstract: A silicon substrate is disposed parallel with an optical disc. A prism for transmitting an incident beam is installed on the silicon substrate. A diffraction grating on a side surface of the prism. A beam splitter for partially reflecting and partially transmitting the laser beam is positioned inside of the prism to be slanted. The beam irradiated from the laser light source is reflected by the beam splitter after having transmitted through the diffraction grating. The reflected beam focuses onto the optical disc via a selective light-transmitting part formed on the upper surface of the prism. The beam is totally transmitted through an inner circular portion of the selective light-transmitting part and half transmitted through a peripheral portion of the selective light-transmitting part.

Abstract: An optical pickup system reproduces an information signal stored on an optical disk including a recording surface. The optical pickup system comprises an objective lens for focusing a light beam, having a P and an S polarizing components, on the recording surface, a first prism provided with an inclined and a side surfaces and a second prism provided with a side surface, wherein the second prism includes a light source for generating the light beam, a first detector and a first and a second 1/4 .lambda. plates, and a first prism includes a second detector and a polarizing film for transmitting only the P-polarizing component of the light beam to the recording surface. In the optical system, the first detector attached at the side surface of the second prism facing the second 1/4 .lambda. plate from outside, for receiving a part of the light beam impinging thereon and reflecting the remaining part of the light beam to the direction of the second 1/4 .lambda.

Abstract: An optical pickup system reads an information signal stored on a recording surface of an optical disk. The optical pickup system comprises a light source for generating a light beam, an optical detector for detecting the information signal off the optical disk, an objective lens for focusing a portion of the light beam impinged thereonto on the optical disk, and converging the light beam reflected by the optical disk on the optical detector and a knife edge provided with a parallelopiped base, made of a material transparent to the light beam, a first and a reflection layers formed on the parallelopiped base, wherein the second reflection layer reflects the portion of the light beam to the objective lens and the first reflection layer reflects the light beam reflected from the optical disk to the optical detector to thereby allowing the optical pickup system to read the information signals off the optical disk.

Abstract: An optical pickup system for selectively detects an information signal from, e.g., a pair of optical disks loaded on a disk tray, wherein each of the optical disks may have a different thickness. The optical pickup system includes a light source for generating a first and a second light beams having a different wavelength from each other, a first wavelength .lambda..sub.1, and a second wavelength .lambda..sub.2, and a beam splitter provided with a first and a second parts, wherein the first light beam impinging onto the first part is partially reflected to the first optical disk, and the second light beam impinging onto the second part is partially reflected to the second optical disk, thereby allowing the optical pickup system to detect an information signal from the respective optical disks.

Abstract: Disclosed is an optical pickup apparatus being manufactured with ease and utilizing the intensity of a laser beam effectively. The optical pickup apparatus comprises a polygonal prism having an upper surface, an incline surface, and a bottom surface. A laser beam emitted from laser source is reflected by the incline surface of the prism and is converged on an optical disc. Then, the reflected laser beam reflected by the optical disc is transmitted through the incline surface of the prism and is reflected by a Fresnel lens at the bottom surface of the prism and finally is focused on the photodetector. The optical pickup apparatus records and reproduces information on and from the optical disc and performs as a focusing servo and a tracking servo of the objective lens by utilizing data of the reflected information beam received by the photodetector.

Abstract: An optical pickup system reads an information signal stored on a recording surface of an optical disk. The optical pickup system comprises a light source for generating a light beam including a P and an S polarization component with a wavelength .lambda..sub.1, a 1/4.lambda.

Abstract: Beams generated from first and second laser light sources are reflected by a beam splitter to proceed toward an optical disc. The laser beams focus onto the optical disc via a selective light-transmitting part installed in front of the optical disc and an objective lens. The selective light-transmitting part is formed by an inner circular part for transmitting only the laser beam of first wavelength and a peripheral part for transmitting only the laser beam of second wavelength. The beam having transmitted through the inner circular part forms the larger beam spot on the disc while that having transmitted through the peripheral part forms the smaller beam spot, so that double beam focuses of different sizes can be formed by a single optical pickup device.

Abstract: A beam generated from a laser light source are reflected by a beam splitter to proceed toward an optical disc. The beam focus onto the optical disc via a selective light-transmitting part installed in front of the optical disc and an objective lens. The beam is totally transmitted through an inner circular portion of the selective light-transmitting part and half transmitted through a peripheral portion of the selective light-transmitting part. The beam transmitted through the inner circular portion forms the larger beam spot on the disc while the beam transmitted through the peripheral portion forms the smaller beam spot, so that spherical aberration to be occurred due to change of the thickness of the optical disc is minimized by using the beam with smaller numerical aperture which has transmitted through the inner circular portion of the selective light-transmitting part.

Abstract: An optical pickup system reads an information signal from stored on a recording surface of an optical disk. The optical pickup system includes a light source for generating a light beam including a P and an S polarization component with a wavelength .lambda..sub.1, a 1/4.lambda. plate for changing the polarization component of the light beam transmitted therethrough, an optical detector for detecting the information signal off the optical disk, and a beam splitter, provided with a first and a second surface, the first surface being capable of reflecting one of the polarization components to the optical disk through the 1/4.lambda. plate and transmitting the light beam reflected from the optical disk changed its polarization component by passing through the 1/4.lambda. plate to the second surface being capable of reflecting the light beam impinging thereon to the detecting means, thereby allowing the optical pickup system to read the information signals off the recording surface.

Abstract: An optical pickup system for regenerating information stored on an optical disk including a pair of recording surfaces thereon, is provided with a pair of light sources, a detector, an objective lens, a signal detection unit, and a beam splitter having a first and a second recording surface. In this system, when the first light source is used for reproducing an information signal on the first recording surface of the optical disk, the first light beam transmitted through the second surface of the beam splitter is used for detecting the focusing error signal of the first recording surface of the optical disk. When the second light source is used for detecting the focusing error signal of the second recording surface of the optical disk, the second light beam reflected from the second surface of the beam splitter is utilized for reproducing an information signal on the second recording surface with the first light source turned off.

Abstract: An optical pickup system reads an information signal from stored on one of a first and a second optical disks alternatively to be loaded on a disk tray, wherein each of the optical disks may have a different thickness. The optical pickup system includes a light source for generating a first and a second light beams having a different wavelength from each other, a first wavelength .lambda..sub.1, and a second wavelength .lambda..sub.2, and an objective lens provided with a first and a second parts, wherein the surface of the first part is coated with a first dielectric film capable of transmitting only the first light beam emitted from the light source, whereas the surface of the second part is coated with a second dielectric film capable of transmitting only the second light beam, but totally reflecting the other light beams impinging thereon, thereby allowing the optical pickup system to detect an information signal from the respective optical disks.

Abstract: An optical pickup system for reading information stored on a first or a second optical disk, each of the optical disks having a different thickness and selectively loaded on a disk tray, is provided with a light source for generating a first or a second light beam depending on the optical disk selectively loaded, each of the first and the second light beams having a different wavelength from each other, .lambda..sub.1, .lambda..sub.2, a knife edge, an optical device including a first and a second parts, an objective lens and a detector. In the above system, if one of the optical disks is selected to be loaded on a disk tray, the light source selects a light beam from the first and the second light beams based on the thickness of the selected optical disk.

Abstract: Disclosed is an optical pickup apparatus being manufactured with ease and utilizing the intensity of a laser beam effectively. The optical pickup apparatus comprises a polygonal prism having an upper surface, an incline surface, and a bottom surface. A laser beam emitted from laser source is reflected by the incline surface of the prism and is converged on an optical disc. Then, the reflected laser beam reflected by the optical disc is transmitted through the incline surface of the prism and is reflected by a Fresnel lens at the bottom surface of the prism and finally is focused on the photodetector. The optical pickup apparatus records and reproduces information on and from the optical disc and performs as a focusing servo and a tracking servo of the objective lens by utilizing data of the reflected information beam received by the photodetector.

Abstract: A both-sided optical disc player for recording/reproducing information on a both-sided disc includes a disc deck having a turntable being shaft-supported by a spindle motor to be rotated for driving the disc and an optical pickup slidably connected on the upper portion of the disc deck. A disc tray guides the disc to the turntable for loading the disc onto the disc deck. A clamp apparatus pressively supports the both-sided disc on the turntable. The both-sided disc seated on the turntable is transferred up and down centering about the optical pickup by a transfer apparatus to reproduce respective sides of the both-sided disc. Thus, trembling of the optical pickup is significantly reduced to realize stable recording/playback operations.

Abstract: Disclosed is an optical pickup having simplified constitution. A light source for radiating laser beam for reading an optical disc is comprised. A beam splitter for separating the laser beam radiated from the light source into transmitting light and reflecting light and for separating light from the optical disc into transmitting light and reflecting light is provided. Installed is an objective lens for converging light from the beam splitter to form a focus on the optical disc and for forwarding light from the optical disc to the beam splitter. A micro fresnel lens attached on one side of the beam splitter is included. The micro fresnel lens generates astigmatism and converges the incident light from the beam splitter. A photodetector receives light from the micro fresnel lens, reproduces information recorded on the optical disc and detects a focus error. The manufacture of the optical pickup is advantageous and the product has improved quality.

Abstract: An integrated optical pickup system for reproducing an information signal stored on a recording surface of an optical disk is comprised of a first optical glass substrate, integrated with a semiconductor laser, a reflection collimating lens, a transmission off axis diffractive object lens and a reflection layer, for impinging a converged light beam onto the optical disk and collimating the converged light beam after being reflected from the recording surface and a second glass substrate, integrated therein with a twin focusing beam splitter and a photo detector, for guiding the collimated light beam from the first glass substrate to the photo detector, thereby allowing the integrated optical pickup system to reproduce the information signal off the recording surface of the optical disk.

Abstract: When a laser beam from an optical pickup is incident on an optical disc, the optical disc comprises a protective layer, a first recording layer having a desired pattern, a coating layer by which one part of the laser beam is reflected with a predetermined reflectance and through which the other part is transmitted, a dielectric layer, a second recording having a desired pattern and formed under the dielectric layer, and a reflective layer by which the laser beam is totally reflected, according to that order from a top of the disc. The disc has the coating layer having the predetermined reflectance between the first and second recording layers, thereby the light amount of the laser beam reflected from the coating layer for reading information of the upper first recording layer becomes larger than the light amount of the laser beam transmitted through the coating layer for reading information of the lower second recording layer.

Abstract: An optical pickup system for alternatively detecting an information signal from, e.g., a pair of optical disks loaded on a disk tray is described, wherein each of the optical disks may have a different thickness. The optical pickup system includes a light source for generating a light beam and an optical device provided with a first and a second parts, wherein a portion of the light beam impinging onto the first part is focused onto the first optical disk, and the remaining portion of the light beam impinging onto the second part is focused onto the second optical disk, thereby allowing the optical pickup system to detect an information signal from the respective optical disk.

Abstract: An optical pickup system for reproducing information signals stored on a first and a second optical disks loaded on a disk tray is described wherein each of the optical disks has a different thickness. The optical system includes a light source for generating a parallel light beam and an optical device provided with a first and a second part, wherein a portion of parallel light beam impinging onto the first part is focused onto the first optical disk, and the remaining portion of the parallel light beam impinging onto the second part is focused onto the second optical disk, thereby allowing the optical pickup system to read the information signals off the respective optical disk.