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

An optical pick-up apparatus for recording and/or reproducing information from first through third recording media, comprising:

• a first light source to emit a light beam having a wavelength corresponding to the first recording medium when the first recording medium is accessed;
• a second light source to emit a light beam having a wavelength corresponding to the second recording medium when the second recording medium is accessed;
• a third light source to emit a light beam having a wavelength corresponding to the third recording medium when the third recording medium is accessed;
• a dichroic beam splitter having first through third input surfaces to receive the light emitted from the first through third light sources, respectively, and an output surface through which the light beams received by the first through third input surfaces are transmitted toward the first, the second, and the third recording media, respectively;
• a converging device to converge each of the light beams transmitted through the output surface of the dichroic beam splitter toward the respective first through third recording media;
• and
• first through third photodetectors to respectively receive the light beams reflected from the respective first through third recording media and which pass through the dichroic beam splitter,
• wherein:
• the dichroic beam splitter comprises:
• a first slant reflection surface to transmit the light beam emitted from the first light source, and to reflect the light beam emitted from the second light source, toward the output surface;
• and
• a second slant reflection surface to transmit the light beam emitted from the first light source, and to reflect the light beam emitted from the third light source, toward the output surface, and
• each of the first and the second slant reflection surfaces comprises repeatedly stacked dielectric layers, each having a refractivity different from an adjacent one of the dielectric layers.

An optical pick-up apparatus for recording and/or reproducing information from first and second recording media, comprising:

• a first light source to emit a light beam having a first wavelength when the first recording medium is accessed, and a second light source to emit a light beam having a second wavelength when the second recording medium is accessed, the first and the second wavelengths corresponding to the first and second recording media;
• a dichroic beam splitter having first and second input surfaces to receive the light beams emitted from the first and second light sources, respectively, and an output surface through which the light beams received by the first and second input surfaces are transmitted toward the first and second recording media, respectively;
• a converging device to converge each of the light beams transmitted through the output surface of the dichroic beam splitter to the respective first and the second recording media;
• and
• first and second photodetectors to respectively receive the light beams reflected from the respective first and second recording media and which pass through the dichroic beam splitter,
• wherein:
• the dichroic beam splitter includes a slant reflection surface consisting of repeatedly alternated stacks of first and second dielectric layers, each of the first and second dielectric layers having corresponding first and second thicknesses such that the slant reflection surface transmits and reflects the light beams emitted from the first and second light source to the output surface,
• the first and second light sources emit light beams having wavelengths of approximately 419 nm and 650 nm, respectively, and
• the first dielectric layer has a refractivity of 1.38 and a thickness of 0.3λ1, and the second dielectric layer has a refractivity of 2.3 and a thickness of 0.5λ1, wherein λ1 indicates a reference wavelength of approximately 1040 nm.

An optical pick-up apparatus for recording and/or reproducing information from first and second recording media, comprising:

• a first light source to emit a light beam having a first wavelength when the first recording medium is accessed, and a second light source to emit a light beam having a second wavelength when the second recording medium is accessed, the first and the second wavelengths corresponding to the first and second recording media;
• a dichroic beam splitter having first and second input surfaces to receive the light beams emitted from the first and second light sources, respectively, and an output surface through which the light beams received by the first and second input surfaces are transmitted toward the first and second recording media, respectively;
• a converging device to converge each of the light beams transmitted through the output surface of the dichroic beam splitter to the respective first and the second recording media;
• and
• first and second photodetectors to respectively receive the light beams reflected from the respective first and second recording media and which pass through the dichroic beam splitter, wherein:
• the dichroic beam splitter includes a slant reflection surface consisting of repeatedly alternated stacks of first and second dielectric layers, each of the first and second dielectric layers having corresponding first and second thicknesses such that the slant reflection surface transmits and reflects the light beams emitted from the first and second light source to the output surface,
• the first and second light sources emit light beams having wavelengths of approximately 410 nm and 650 nm, respectively, and
• the first dielectric layer has a refractivity of 1.38 and a thickness of 0.15λ1, and the second dielectric layer has a refractivity of 2.3 and a thickness of 0.25λ1, wherein λ1 indicates a reference wavelength of approximately 660 nm.

An optical pick-up apparatus for recording and/or reproducing information from first and second recording media, comprising:

• a first light source to emit a light beam having a first wavelength when the first recording medium is accessed, and a second light source to emit a light beam having a second wavelength when the second recording medium is accessed, the first and the second wavelengths corresponding to the first and second recording media;
• a dichroic beam splitter having first and second input surfaces to receive the light beams emitted from the first and second light sources, respectively, and an output surface through which the light beams received by the first and second input surfaces are transmitted toward the first and second recording media, respectively;
• a converging device to converge each of the light beams transmitted through the output surface of the dichroic beam splitter to the respective first and the second recording media;
• and
• first and second photodetectors to respectively receive the light beams reflected from the respective first and second recording media and which pass through the dichroic beam splitter,
• wherein:
• the dichroic beam splitter includes a slant reflection surface consisting of repeatedly alternated stacks of first and second dielectric layers, each of the first and second dielectric layers having corresponding first and second thicknesses such that the slant reflection surface transmits and reflects the light beams emitted from the first and second light source to the output surface,
• the light beams emitted from the first and the second light sources have wavelengths of approximately 410 nm and 780 nm, respectively, and
• the first dielectric layer has a refractivity of approximately 1.38 and a thickness of 0.15λ1, and the second dielectric layer has a refractivity of approximately 2.3 and a thickness of 0.25λ1, wherein λ1 indicates a reference wavelength of approximately 660 nm.

An optical pick-up apparatus for recording and/or reproducing information from first and second recording media, comprising:

• a first light source to emit a light beam having a first wavelength when the first recording medium is accessed, and a second light source to emit a light beam having a second wavelength when the second recording medium is accessed, the first and the second wavelengths corresponding to the first and second recording media;
• a dichroic beam splitter having first and second input surfaces to receive the light beams emitted from the first and second light sources, respectively, and an output surface through which the light beams received by the first and second input surfaces are transmitted toward the first and second recording media, respectively;
• a converging device to converge each of the light beams transmitted through the output surface of the dichroic beam splitter to the respective first and the second recording media;
• and
• first and second photodetectors to respectively receive the light beams reflected from the respective first and second recording media and which pass through the dichroic beam splitter,
• wherein:
• the dichroic beam splitter includes a slant reflection surface consisting of repeatedly alternated stacks of first and second dielectric layers, each of the first and second dielectric layers having corresponding first and second thicknesses such that the slant reflection surface transmits and reflects the light beams emitted from the first and second light source to the output surface,
• the light beams emitted from the first and the second light sources have wavelengths of approximately 410 nm and 780 nm, respectively, and
• the first dielectric layer has a refractivity of approximately 1.38 and a thickness of 0.3λ1, and the second dielectric layer has a refractivity of approximately 2.3 and a thickness of 0.5λ1, wherein λ1 indicates a reference wavelength of approximately 600 nm.

An optical pick-up device to record and/or reproduce information from a plurality of recording media of different formats, one of which is to be accessed at a given time, the optical pick-up device comprising:

• first, second, and third light sources to emit light beams of different wavelengths corresponding respectively to the plurality of recording media, depending upon which one of the plurality of recording media is to be accessed;
• a dichroic beam splitter including first and second slant reflection surfaces oblique to the light beams of the first, second, and third light sources and which selectively reflect and transmit the light beams of first, second, and third light sources based upon the wavelengths of the light beams of the first, second, and third light sources;
• a converging device to converge each of the light beams transmitted from the dichroic beam splitter to the recording media;
• and
• a plurality of photodetectors to respectively receive the light beams reflected from the plurality of recording media and which pass through the converging device and the dichroic beam splitter and are incident upon the at least one slant reflection surface,
• wherein:
• the first slant reflection surface comprises repeatedly alternated stacks of first and second dielectric layers, wherein the first and second dielectric layers have different refractivities, the first slant reflection surface transmits the light beam emitted from the first light source, and reflects the light beam emitted from the second light source, toward the output surface, and
• the second slant reflection surface comprises repeatedly alternated stacks of third and fourth dielectric layers, wherein the third and fourth dielectric layers have different refractivities, the second slant reflection surface transmits the light beam emitted from the first light source, and reflects the light beam emitted from the third light source, toward the output surface.

An optical pick-up device to record and/or reproduce information from a plurality of recording media of different formats, one of which is to be accessed at a given time, the optical pick-up device comprising:

• first and second light sources to emit light beams of different wavelengths corresponding respectively to the plurality of recording media, depending upon which one of the plurality of recording media is to be accessed;
• a dichroic beam splitter including a slant reflection surface oblique to the light beams of the first and second light sources and which selectively reflects and transmits the light beams of the first and second light sources based upon the wavelengths of the light beams of the first and second light sources;
• a converging device to converge each of the light beams transmitted from the dichroic beam splitter to the recording media;
• and
• a plurality of photodetectors to respectively receive the light beams reflected from the plurality of recording media and which pass through the converging device and the dichroic beam splitter and are incident upon the at least one slant reflection surface,
• wherein the slant reflection surface consists of repeatedly alternated stacks of first and second dielectric layers, wherein the first and second dielectric layers have corresponding first and second thicknesses, the slant reflection surface transmits the light beam emitted from the first light source, and reflects the light beam emitted from the second light source.