摘要:
An optical system for illuminating a sample with a line beam comprises a light source (24), a beam shaper (30) for transforming the beam of light emitted by the light source into an intermediate astigmatic image and an imaging system for transforming the intermediate astigmatic image into a final astigmatic image and for illuminating the sample. The beam shaper provides different non-unity magnifications in a lateral plane and in a transversal plane, and comprises a toroidal entrance surface for implementing the angular magnification and angular reduction and a toroidal exit surface with finite radii of curvature. The invention enables the use of existing beam shaping apparatus, normally used to make a light output have a more circular cross section, in combination with the imaging system, in order to provide line beam illumination of a sample.
摘要:
An optical beam shaper comprises a polarization-dependent phase adjustment member which applies a phase pattern of equal magnitude and opposite sign to two orthogonal polarization states. In a preferred embodiment the beamer shaper is a dif tractive element made of a birefringent material, such as a photo-polymerizable liquid crystal polymer frozen in a uniaxial alignment, said dif tractive element comprising a plurality of zones, each zone having a stepped thickness defining a plurality of steps. The beam shaper can be used to introduce astigmatism to a polarized light beam or to undo the astigmatism to a beam with an orthogonal polarization state. The beam shaper is advantageously used within a detection device, such as a fluorescence scanner.
摘要:
An optical identifier (1) can be used as a Physical Unclonable Function for producing a speckle pattern, as a response, upon being challenged with a light beam, as a challenge. This property can be used for identification of the optical identifier or of an object attached thereto, for the authentication of an information carrier or for generation of transaction keys. Since the response obtained in response to given challenge is highly sensitive to the relative position of the optical identifier, light beam source and detector for the speckle pattern, this relative position has to be accurately adjusted to reliably obtain the same response to a given challenge. To this aim, an optical identifier is proposed having an alignment area (3) for splitting an incident beam into distinct beams (6, 7) which can be detected as alignment signals (10a, 10b, 10c, 10d) on a detector (8) and used for the monitoring and for the adjustment of said relative position.
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 different formats of optical record carrier. The device includes a first radiation source (16), a second radiation source (70) and a third radiation source (72) arranged to emit radiation beams having a predetermined first, second and third, different, wavelength. The device further includes a redirector (15) for redirecting the second and third radiation beams. The redirector (15) includes a diffraction structure arranged to redirect the second radiation beam from the second input optical path (48) along the second output optical path (50) and to redirect the third radiation beam from the third input optical path along the third output optical path, so as to improve the colinearity of the second and third output optical paths with respect to a first output optical path of the redirector.
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:
The invention relates to an information carrier containing a non-clonable optical identifier (2) having an optical scattering medium (3) for being challenged by a light beam (5) and for scattering said light beam (5). In order to provide a secure information carrier (1), it is proposed that it further comprises a light absorbing means (3, 4) for reducing the intensity of said light beam (5) so that an integration time for obtaining a response signal by integrating the scattered light beam (8) is extended.
摘要:
An optical arrangement of at least a coherent light source (1), a strongly scattering object (5) (the PUF), and a pixe-lated photo-detector (6), wherein the pixels are comparable in size with the bright and dark patches of the speckle pattern produced by coherent radiation traversing the scattering object (5). Quantitively, the pixel size should be roughly λ/NA, where λ is the wave-length, and (i) NA=a/z for free-space geometry, with a being the beam radius and z being the distance between the exit surface of the PUF (5) and the pixelated detector (6), or (ii) NA is the numerical aperture of a lens (7) in an imaging geometry. In a preferred embodiment of the invention, there are tentative requirements that the pixels should be at least smaller than ηmaxλNA and preferably larger than ηmaxλ/NA, where (in an exemplary embodiment) ηmax=5 and ηmin=0.05, say. It will be understood by a person skilled in the art that the present invention is concerned with the optical arrangement of the PUF (5) and the photo-detector (6), rather than the photo -detector (6) per se.
摘要:
The invention relates to an optical pickup apparatus comprising a photodetector (302) which comprises a first segment (A) and a second segment (B), and an optical element (301) intended to receive an incident light beam, said optical element (301) comprising:—a first portion (L) comprising diffraction means for generating a first 0th diffraction order light beam (A(0)) on said first segment (A), and a first non-0th diffraction order light beam (B(+1)) on said second segment (B),—a second portion (R) comprising diffraction means for generating a second 0th diffraction order light beam (B(0)) on said second segment (B), and a second non-0th diffraction order light beam (A(+1)) on said first segment (A) Use: Optical pickup apparatus
摘要:
Tracking system for guiding an optical beam on tracks on an optical disc, said tracking system comprising a photodetector (A1, A2) for detecting optical beams derived from said optical beam, said photodetector generating a first output signal (A) and a second output signal (B), said tracking system comprising first processing means for generating a first differential signal (PP(DC)) corresponding to the low-frequency part of a difference between said first and second output signals. The tracking system comprises second processing means for generating a tracking error signal (PP(AC/DC)) defined by the addition of said first differential signal (PP(DC)) to a second differential signal (PP′(AC)), said second differential signal corresponding to a fraction of the difference in amplitude of the high-frequency components of said first and second output signals. Use: Optical disc player/writer.