Chong-Sam Chung

Bio: Chong-Sam Chung is an academic researcher from Samsung. The author has contributed to research in topics: Lens (optics) & Light beam. The author has an hindex of 15, co-authored 174 publications receiving 1091 citations.

Compatible optical pickup

Abstract: An optical pickup which is compatible with at least one high density recording medium that uses a blue-violet beam and at least one lower density recording medium, the optical pickup including: an optical unit to selectively emit one of a plurality of beams with different wavelengths onto one of the at least one high density recording medium and the at least one lower density recording medium, and to receive the respective beam reflected from the respective recording medium; and a holographic objective lens to focus the respective beams emitted by the optical unit on a recording surface of the respective recording medium, the holographic objective lens including a first holographic lens region and a second holographic lens region located inside the first holographic lens region, wherein holographic patterns of the first and second holographic lens regions respectively produce a first effective numerical aperture (NA) for the at least one high density recording medium and at least one additional effective NA suitable for the at least one lower density recording medium.

Lens device comprising light blocking means and an optical pickup apparatus using the lens device

Abstract: A lens device which can be used as an objective lens in an optical pickup apparatus includes an objective lens provided along a light path facing a disc and having a predetermined effective diameter, and light controlling means provided along the light path for controlling the light in an intermediate region between near and far axes of an incident light beam, thus providing a simplified and inexpensive device for using discs of differing thickness in a single disc drive, by reducing the spherical aberration effect.

Compatible optical pick-up apparatus for recording and reproducing information from recording media having different formats

Abstract: An optical pick-up apparatus for recording and reproducing information from recording media using a first, second, and third light source to emit light beams having various wavelengths corresponding to a first, second and third recording media, respectively. A dichroic beam splitter has a first, second, and third input surface for receiving the light beams emitted from the first, second and third light sources, respectively, and an output surface through which the light beams received through the input surfaces is transmitted toward the first, second, and third recording media. A converging device converges the light beams transmitted through the output surface of the dichroic beam splitter toward the first, second, and third recording media, and a photodetector receives light beams reflected from the first, second, and third recording media that has been transmitted through the dichroic beam splitter.

Optical pickup having an objective lens compatible with a plurality of optical disk formats

Abstract: An optical pickup compatible with a plurality of optical recording media each using light of a different wavelength. The optical pickup includes at least one light source, an objective lens having a function of focusing light emitted from the light source into the optimal light spot on an information recording surface of one of the plurality of the optical recording media, and a light detector to detect light transmitted through the objective lens after being reflected from the information recording surface of the optical recording medium on which the light spot is formed. The objective lens has an inner area, an annular lens area and an outer area such that the annular lens area divides the inner area from the outer area and has a ring shape centered at a vertex. The inner area, the annular lens area and the outer area have aspherical surface shapes to focus light transmitted through the inner area and the outer area into a single light spot by which information can be read from the information recording surface of a relatively thin first optical recording medium and scatter light transmitted through the annular lens area located between the inner area and the outer area so that information cannot be read from the information recording surface of the first optical recording medium, during reproduction of the first optical recording medium. The inner area and the annular lens area transmit light into a single light spot by which information can be read from the information recording surface of a relatively thick second optical recording medium and scatters light transmitted through the outer lens area so that information cannot be read from the information recording surface of the second optical recording medium, during reproduction of the second optical recording medium.

Phase compensator and compatible optical pickup using the phase compensator

Abstract: A compatible optical pickup for recording and/or reproducing information on/from multiple kinds of optical discs having different thicknesses by selectively using source lights of respective different wavelengths corresponding to a kind of disc and using a common objective lens. At least one phase compensator, which compensates a phase of a light having a particular wavelength to correct for spherical aberration due to a thickness difference between the kinds of optical discs and/or chromatic aberration due to a wavelength difference between the required source lights, is positioned between the source lights and an entrance pupil of the objective lens. Each phase compensator compensates light of at least one wavelength and passes light of at least one other wavelength without significant relative phase alteration. By using two phase compensators, the optical pickup may be made compatible with at least three kinds of optical discs.

Uniform illumination system

Abstract: A compact and efficient optical system featuring planar multi-layered LED light source arrays concentrating their polarized or unpolarized output within a limited angular range. The optical system manipulates light emitted by a planar light emitters such as electrically-interconnected LED chips. Each light emitting region in the array is surrounded by reflecting side-walls whose output is processed by elevated prismatic films, polarization converting films, or both. The optical interaction between light emitters, reflecting sidewalls and the elevated prismatic films create overlapping virtual images between emitting regions that contribute to the greater optical uniformity. Practical illumination applications of such uniform light source arrays include compact LCD of DMD video image projectors, as well as general lighting, automotive lighting, and LCD backlighting.

Method and device for manipulating color in a display

Abstract: Embodiments include methods and devices for controlling the spectral profile and color gamut of light produced by an interferometric display. Such devices include illuminating a display with selected wavelengths of light. Embodiments also include a display comprising separate sections that output different predetermined colors of light. Other embodiments include methods of making the aforementioned devices.

Liquid crystal lens element and optical head device

Abstract: There is provided a liquid crystal lens element having a lens function capable of performing spherical aberration correction including a power component equivalent to a focal point change of the stable incident light in accordance with the voltage applied. One (12) of the two transparent substrates (11, 12) has a transparent electrode (15) and a Fresnel lens surface (17) while the other (11) of the two transparent substrates has a phase correction surface (18) and a transparent electrode (16). Thus, by arranging the Fresnel lens surface (17) and the liquid crystal layer (13) between the two transparent electrodes (15, 16), the substantial refraction factor distribution of the liquid crystal layer (13) is changed according to the voltage applied, so that positive/negative power is given to the wavefront transmitting through the liquid crystal layer (13), the Fresnel lens surface (17), and the phase correction surface (18).

Dynamic identification of other users to an online user

Abstract: Informing a user of a large scale network dynamically of other network users includes determining dynamically an online context of the user. Other users presently within the online context of the user are identified and trait information is stored that is related essentially only to the user or to the other users in a users store associated with the online context. The user is informed dynamically of the other users based on the stored trait information, such as, for example, an age or other demographic identifier, or information indicative of an expertise, interest, preference, user type and/or other quality of the user or of the other individual.

Thin illumination system

Abstract: The present invention introduces a new class of thin doubly collimating light distributing engines for use in a variety of general lighting applications. Output illumination from these slim-profile illumination systems whether square, rectangular or circular in physical aperture shape is directional, square, rectangular or circular in beam cross-section, and spatially uniform and sharply cutoff outside the system's adjustable far-field angular cone. Some embodiments provided include thin light distributing engines which provide input light collimated in one meridian and a light distributing element that maintains input collimation while collimating output light in the un-collimated orthogonal meridian, in such a manner that the system's far-field output light is collimated in both its orthogonal output meridians. The present invention can also include optical films that process the engine's doubly collimated output illumination so as to increase its angular extent one or both output meridians without changing beam shape or uniformity.