The target structure of this invention is comprised of a thin optically transparent lightguide sheet, preferably two sheets bonded together with flat sides. The thin sheet material is chosen to make a good pocket-size lightguide and provide an adequate tradeoff to cost, manufacturing ease, and internal reflective loss, and may be colored to provide an optical filter enhancing contrast of the viewed image by rejecting unwanted light. At the entrance edge of the target are side-by-side formations generating optically the lens and axicon function, and separately the reference lens function. The exit edges of the sheets are either flat and perpendicular to the faces, or at such an angle as to direct images at a prescribed angle with respect to the face of the sheet(s). The entrance edge of the one sheet is formed with a curve to produce the optical lens and axicon functions, the shape of which can be chosen to enhance any difference occuring between the images when the incoming beam is not on center. The other sheet is similarly designed to the lens function that produces a single image reference line. The exit ends of each lightguide are made in several ways depending on where the images are to be viewed. The output ends may be viewed from the edge of the target, as for drop ceiling rail alignment, and the images appear directly on the ends.
CROSS-REFERENCE TO RELATED APPLICATION
This invention relates to laser alignment systems such as disclosed in U.S. patent applications Ser. No. 08/520,853 and Ser. No. 08/520,852 (now U.S. Pat. No. 5,710,647 issued Jan. 20, 1998) both filed Aug. 30, 1995, and to an improved passive portable target for such systems.
This disclosure concerns methods for transmitting a signal in an optical system. In one example, the method begins when an optical signal is generated. Then, the optical signal is manipulated such that the optical signal defines a substantially annular intensity profile, where power of the optical signal varies in the intensity profile. Finally, the optical signal is launched into an input face of an optical fiber such that a predetermined part of the intensity profile of the optical signal is located proximate an optical axis associated with the optical fiber.
An optical system for high speed transmission of optical data. The system may condition light signals from a source for projection into an optical medium that is to convey the signals with high speed to another place. This conditioning may result in the light having an annular intensity distribution or profile. Much of the intensity of the light is near the periphery of the optical medium. This medium may be an optical fiber. This annular distribution may be attained with an optical element having a slope discontinuity or light from it being defocused to a certain extent at the optical medium. Either of these characteristics or both of them may used in the optical system so it can transmit light signals at very high rates.
