摘要:
In an optical scanning device (10) capable of scanning an information plane of an optical record carrier (5) of different types such as BD, DVD and CD, the diameter of the radiation spot on the detector (7) is dependent on the numerical aperture of the objective system (4) that is used for scanning the record carrier An optimal design of the optical detection system for scanning a BD, result in a small radiation spot for the other types such as DVD and CD. By implementing an optical element (13) that increases the diameter of the radiation spot in the situation a DVD or CD is scanned, the influence of stray light is reduced and the tracking signals are improved
摘要:
An optical scanning device (1) includes a radiation source (7), a detector (23) and a beam splitter (9). The radiation source (7) provides an incident radiation beam (4, 20) along a first optical path (19a) for scanning an information layer (2) of an optical record carrier (3). The detector (23) detects at least a portion of the radiation beam (22) reflected from the optical record carrier (3). The beam splitter (9) transmits the incident radiation beam (4) received from the radiation source along the first optical path (19a) towards the optical record carrier. The beam splitter (9) also transmits the reflected beam (22) received from the optical record carrier (3) along a second, different optical path (19b) towards the detector. The optical scanning device further includes a beam-deflecting element (30; 130; 230; 330; 630; 830; 930) positioned on the second optical path (19b) between the beam splitter (9) and the detector (23). The beam-deflecting element (30; 130; 230; 330; 630; 830; 930) is arranged to controllably deflect the path of the reflected radiation beam (22) for adjusting the lateral position of said reflected radiation beam incident upon the detector (23) over a predetermined range.
摘要:
An optical scanning device for scanning an information layer (2) of an optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam of a first polarization along a first optical path, and a second radiation beam of a second, different polarization along a second, different optical path. An objective lens system, having an optical axis (19a), is arranged to converge the radiation beams on the information layer A beam-deflecting element (30) comprising a birefringent material is orientated such that each of said polarized radiation beams experiences a different index of refraction upon passing through the birefringent material, and is arranged to refract at least the first radiation beam towards the optical axis.
摘要:
A optical scanning device (1) for scanning an information layer (2) with a radiation beam (25) in a writing mode and a reading mode comprises a radiation source (7) for emitting the beam and an objective lens (10) for converging the beam so as to form a scanning spot (19) in the information layer. The device also includes a scanning spot power switch (20) for switching the size of the cross-section of the beam between a first size at the writing mode and a second, larger size at the reading mode so as to switch the rim intensity of the beam between a first intensity level (Irim,writing) at the writing mode and a second, higher intensity level (Irim,reading) at the reading mode, thereby switching the light power of the scanning spot between a first power level (Pwriting) at the writing mode and a second, lower power level (Preading) at the reading mode.
摘要:
An optical scanning device (1) for scanning an information layer (2) of an optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam along a first optical path, and a second radiation beam along a second, different optical path. An objective lens system (8) converges the radiation beams on the information layer A beam-deflecting element (30) is arranged to refract said second radiation beam towards the optical axis of the lens system. The beam-deflecting element includes at least one fluid (A). A controller is provided to vary the configuration of the fluid to control the amount of refraction provided by the beam deflector element over a predetermined range.
摘要:
An optical scanning device (1) for scanning at least one information layer (2) of at least one optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam (4) comprising a first wavelength, an objective lens system (8) for converging the first radiation beam on a respective information layer (2), an information detector (23) for detecting at least a portion of the first radiation beam (22) reflected from the respective information layer, for determining information on said layer, and a spherical aberration detection system. The spherical aberration detection system includes an aberration detector (24) for detecting at least a portion of the reflected first radiation beam for determining spherical aberration of the first radiation beam, and a diffractive element (26) for diffracting at least a portion of the reflected first radiation beam towards the aberration detector (24), and for transmitting at least a portion of the reflected first radiation beam towards the information detector (23). In a first mode of operation the grating is arranged to introduce a phase change to an incident portion of a radiation beam for transmitting that portion towards the information detector (23). In a second mode of operation the grating is arranged to introduce a phase change to an incident portion of the reflected first radiation beam for diffracting that portion towards the aberration detector (24).
摘要:
An illumination device comprising a light source (2), an electro-wetting based optical element (1, 10), arranged in front of the light source to allow refraction of a beam of light emitted from said light source, and driving means (9) arranged to operate said optical element between at least two predefined states, said states being adapted to result in refracted beams having different light intensity distribution. According to this design, the electrowetting based optical element can be used to dynamically alter the light intensity distribution of the illumination device between a number of predefined states.
摘要:
The invention relates to an optical system comprising a fluid chamber 1 and a birefringent part. The fluid chamber comprises first and second fluids 10, 12 having different indices of refraction, the interface between the fluids forming a meniscus 14. The birefringent part is capable of varying characteristics of a first radiation beam 3b and a second radiation beam 3c, the first and second radiation beams having different polarisations. Variation in the configuration of the meniscus causes variation in the characteristics of the first radiation beam and the second radiation beam. Variation in the configuration of the meniscus may be controlled by electrowetting.
摘要:
An optical scanning device for scanning an optical record carrier comprising an information layer. Crosstalk cancellation is provided using a phase modulating element (40, 140) for generating a non-rotationally-symmetric phase profile in a subsidiary radiation beam. The phase profile varies with an azimuthal angle measured about the optical axis of the beam portion, the phase profile varying such that successively different phases are introduced in at least five locations which are each at successive azimuthal angles (φ1, φ2, φN) and each at a given radial distance from the optical axis, wherein the phase profile is such that the phases introduced, when taken in modulo 2π form, successively cycle through 0 to 2π at least twice, whereby the subsidiary beam spot is provided with an intensity distribution on the information layer which overlaps that of the side-lobe of the main beam spot.
摘要:
A device (1) for scanning an optical disc (6), the disc (6) comprising substantially parallel data tracks (10). The device (1) comprises an optical unit for creating track light spots (12) on the data tracks (10) and a plurality of detector light spots on a plurality of signal detectors. The device further comprises a focus error unit for with a beam manipulating element (21, 22, 22a, 92) for providing for at least one of the reflected beams a first optical path (24) to a first segmented detector (8a) and a second optical path (25) to a second segmented detector (8b). The lengths of the first optical path (24) and the second optical path (25) exhibit a difference (Dd), such that an intensity distribution of a first detector light spot on the first segmented detector (8a) is equal to an intensity distribution of a second detector light spot on the second segmented detector (8b) when the at least one track light spot is correctly focussed and that the intensity distribution on the first segmented detector (8a) differs from the intensity distribution on the second segmented detector (8b) when the at least one track light spot is not correctly focussed. The difference (Dd) is substantially less than a quotient of a distance between two adjacent detector light spots (Ds) and a numerical aperture (NA) of the lens (7). A dimension (D1) of a light detecting area of the segmented detectors in a direction of adjacent detector light spots is less than the distance (Ds) between two adjacent detector light spots.