High-environmental-resistance Jisso Structure for a Slim Optical Head with a Resin Housing

Ochi, Manabu; Satake, Mitsuo; Kawamura, T.; Izumi, Katsuhiko; Ide, Tomohiro; Oozeki, Yoshio

doi:10.1299/kikaic.74.753

Cited by 2 publications

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“…The position deviation of the beam spot on the detector becomes the sum of two components, as shown in equation 3: Δ1 is due to the displacements and tilts with respect to their optical axes of the optical components, and Δ2 is due to their axial displacements. Δ1 is given as the second component of the output polar vector calculated by adding and subtracting the products of a ray transfer matrix chain representing the transfer from each optical component to the detector with its small displacement and tilt vector (Ochi et al, 2008).…”

Section: Formulation Of Position Deviation Of Beam Spot On Detectormentioning

confidence: 99%

“…To do that, we adopt our previously proposed method that can passively compensate for the reversible optical misalignment due to temperature change. This method is to arrange the bond position and direction of each component in order to tend to displace or tilt a desired amount in a desired direction with temperature variations (Ochi et al, 2006(Ochi et al, , 2008. This method allows the effects of displacement and tilt of each component on the optical misalignment to balance each other out.…”

Section: Introductionmentioning

confidence: 99%

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Heat- and humid-proof adhesive joints for optical pickup

Ochi

Kitada

Konishi

2019

JAMDSM

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Our previously proposed method for arranging adhesive joints for an optical assembly was adopted to resist long-term exposure to severe environments. This method is expected to passively compensate for permanent optical misalignment due to long-term exposure to hot and humid conditions by arranging the bonding direction and position of each optical component in order to tend to displace or tilt a desired amount in a desired direction over time. We calculated the beam spot deviation on a detector, which is an indicator of misalignment of the optical assembly due to heat, humidity, and time effects on adhesive joints. We arranged to adhesively bond the laser diode to the holder from the top so that the laser diode could be lifted up due to the moisture expansion of the adhesive joint over time. The developed adhesive joints arrangement had a great advantage in that upward displacement of the laser diode compensates for beam spot deviation caused by tilt of the prism and displacement of the detector along the warp deformation of the housing. The calculated and measured results showed that the beam spot deviation was within about ±5 % after the optical pickup was left at 60 °C and 90 %RH for 336 hours. It is concluded that our method for arranging adhesive joints of each component effectively compensates for passively permanent optical misalignment that occurs after long-term exposure to hot and humid conditions.

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Section: Formulation Of Position Deviation Of Beam Spot On Detectormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat- and humid-proof adhesive joints for optical pickup

Ochi

Kitada

Konishi

2019

JAMDSM

Self Cite

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“…It is noted that the refractive indexes, curvature radiuses, and gap values must be sign-changed each time the laser beam is folded (Gerrard and Burch, 1975). Using paraxial approximation, the incident angle deviation of laser beam onto objective lens θO ( f ) can be given as the second component of the output polar vector calculated by adding and subtracting the products of a ray transfer matrix chain representing the transfer from each optical component to the objective lens with its small displacement and tilt vector (Ochi et al, 2008).…”

Section: Formulation Of Incident Angle Deviation Of Laser Beam Onto Omentioning

confidence: 99%

Analysis of beam spot deviation considering vibration of components in optical pickup

Ochi

Kimura

Satake

2018

Mechanical Engineering Journal

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An optical disc drive uses an optical pickup to read and write data by focusing a laser beam on the data plane of a rotating disc. The pickup is required to keep the beam spot on the current track. The latest trend of replacing metal pickup housing with plastic easily excites elastic deformation modes of the pickup housing. Optical components mounted on the housing are vibrated at the mode frequencies of the housing as well. These vibrations tilt the incident angle of a laser beam entering the objective lens and results in the displacement of the beam spot on the data plane. Our purpose in this paper is to improve the accuracy of a vibration model for optical pickups by considering the effect of the elastic deformation modes of the housing in addition to the commonly used mechanical dynamics of an objective lens actuator in order to predict stability in a tracking servo system. The effect of the elastic deformation modes of the housing was formularized as the incident angle deviation and was calculated by adding and subtracting the products of a ray transfer matrix chain representing the transfer from each optical component to the objective lens with its small displacement and tilt vector. This new vibration model reproduced an increased gain around a frequency of 20 kHz in the measured open-loop transfer function of the tracking servo system with 4% error in frequency, which was entirely unexpected in the context of existing vibration models for optical pickups. The calculated results also identified the most influential vibration modes of the housing and estimated the effectiveness of stiffening the housing with 17% error.

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High-environmental-resistance Jisso Structure for a Slim Optical Head with a Resin Housing

Cited by 2 publications

References 0 publications

Heat- and humid-proof adhesive joints for optical pickup

Heat- and humid-proof adhesive joints for optical pickup

Analysis of beam spot deviation considering vibration of components in optical pickup

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