A Very Small Holographic Optical Pick-up Head with a Movable Single-Assembly Optical System

Kadowaki, Shin-ichi; Komma, Yoshiaki; Nishino, Seiji; Hori, Yasuhiko; Katô, Makoto

doi:10.1143/jjap.31.542

Cited by 7 publications

(2 citation statements)

References 1 publication

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“…For its superior optical stability against objective lens shift and/or tilt, an optical pickup that integrates all optical components into the moving head has been desired. 1) To realize such an integrated optical pickup, there are two issues that must be solved. The first is to miniaturize the optical system in the moving head.…”

Section: Introductionmentioning

confidence: 99%

Integrated Catadioptric Pickup with Ferrofluidic Cooling Structure

Onozawa¹,

Yamanaka²,

Okuda³

et al. 2006

jjap

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We have developed a novel integrated catadioptric pickup with a ferrofluidic cooling structure for digital versatile discs (DVDs). To miniaturize the optical system, we made the catadioptric system on a moving head. The catadioptric system consists of a holographic catadioptric lens (HCL), a reflective mirror, a laser diode (LD), and a photodiode IC (PDIC). The HCL has a holographic surface, an aspherical mirror and two aspherical surfaces. This system realized the integration of all optical components into the moving head. The height of the optical system was 8.6 mm including the working distance. To realize efficient heat transfer without sacrificing the motion of the moving head, we developed a cooling structure in which gaps between magnets and coils are filled with ferrofluid. The thermal characteristics were as good as those of conventional optical pickups, proving that the ferrofluidic cooling structure has superior cooling performance. The ferrofluid did not sacrifice the motion of the moving head because of its fluidity.

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Section: Introductionmentioning

confidence: 99%

Integrated Catadioptric Pickup with Ferrofluidic Cooling Structure

Onozawa¹,

Yamanaka²,

Okuda³

et al. 2006

jjap

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“…A beamsplitter like an HOE leads the reflected beam from the disk onto the photodetectors (PDs) in the photo-IC. On the other hand, in spite of its superior characteristics such as optical stability against the objective lens shifts and/or tilts, the DIOS-type optical pick-up has not been commercial reality yet [1]. There are two problems with the DIOS-type pick-ups: (1) poor heat dissipation and (2) limitation in size reduction.…”

Section: Introductionmentioning

confidence: 99%

A novel integrated catadioptric pick-up with ferrofluid cooling structure

et al. 2004

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We propose an integrated catadioptric pick-up (ICPU) with ferrofluid cooling structure for optical disks like DVD. An objective lens and a holographic optical element (HOE) are integrated into a single optical element, called holographic catadioptric lens (HCL). This enables the integration of all optical components including a laser diode (LD) into a moving part of the ICPU. The gaps between the moving part and the fixed optical base are filled with a high-thermal-conductivity ferrofluid, which is supported by magnetic field. With this configuration, Joule heat generated in the moving part is effectively dissipated to the optical base through the ferrofluid without sacrificing the motion of the moving part for its fluidity. The optical characteristics and the cooling performances are applicable to the future extremely small optical disk systems.

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A Holographic Optical Element for an Integrated Optical Head

Kmma

Kadowaki

Nishino

et al. 1996

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Diffraction ef~:ciencies of a reflection-type blazed holographic optical element (HOE) are analyzed and optimized L0r use in a totally integrated optical head. The HOE, consisting of four-step phase levels, was fabricated by a double-etching process. By controlling each etching depth, signal light power efficiency was maximized to 16% and the power ratio of noise components relative to signal light power was suppressed to 21%. Diffraction efiiciencies were made uniform over the entire HOE in oblique positioning by controlling the respective step widths of the HOE.

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A Very Small Holographic Optical Pick-up Head with a Movable Single-Assembly Optical System

Cited by 7 publications

References 1 publication

Integrated Catadioptric Pickup with Ferrofluidic Cooling Structure

Integrated Catadioptric Pickup with Ferrofluidic Cooling Structure

A novel integrated catadioptric pick-up with ferrofluid cooling structure

A Holographic Optical Element for an Integrated Optical Head

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