66 results about "Beam homogenizer" patented technology

There is provided a beam homogenizer which can unify the energy distribution of a linear laser beam in a longitudinal direction. In the beam homogenizer including cylindrical lens groups for dividing a beam, and a cylindrical lens and a cylindrical lens group for condensing the divided beams, the phases, in the longitudinal direction, of linear beams passing through individual cylindrical lenses of the cylindrical lens group for condensing the divided beams are shifted, and then, the beams are synthesized, so that the intensity of interference fringes of the linear beam on a surface to be irradiated is made uniform.

A laser beam is concentrated using an objective lens and radiated on a amorphous silicon film or polycrystalline silicon film having a grain size of one micron or less, the laser beam being processed from a continuous wave laser beam (1) to be pulsed using an EO modulator and to have arbitrary temporal energy change while pulsing ; (2) to have an arbitrary spatial energy distribution using a beam-homogenizer, filter having an arbitrary transmittance distribution, and rectangular slit; and (3) to eliminate coherency thereof using a high-speed rotating diffuser. In this manner, it is possible to realize a liquid crystal display device in which a driving circuit comprising a polycrystalline silicon film having substantially the same properties as a single crystal is incorporated in a TFT panel device.

A system for homogenizing the intensity profile of light includes a plurality of fiber coupled light sources for emitting fiber output beams from fiber output ends, and a light pipe optically coupled to the fiber output beams for producing a uniform light pipe output beam, an interleaver that transmits a first set of fiber output beams and reflects a second set of fiber output beams so that the principal rays of the fiber output beams propagate in a common plane, a first optical element for converging the principal rays, and a second optical element for telecentrically imaging the beams into the light pipe such that the principal rays of the beams propagate parallel to each other and the beams are focused in the light pipe in a focal plane transverse to the direction of propagation.

An optical system (in FIGS. 1A and 1B) wherein a rectilinear laser beam of homogeneous energy distribution is defined for annealing a non-single crystalline semiconductor film (a surface to-be-irradiated 1108), is constructed of reflectors (1106, 1107 etc.) easily and inexpensively without including lenses of transmission type. The rectilinear laser beam can be defined having a length of at least 600 (mm) which corresponds to the shorter latus of a large-sized substrate for mass production.

A method and apparatus for producing with a gas discharge laser an output laser beam comprising output laser light pulses, for delivery as a light source to a utilizing tool is disclosed which may comprise a beam path and a beam homogenizer in the beam path. The beam homogenizer may comprise at least one beam image inverter or spatial rotator, which may comprise a spatial coherency cell position shifter. The homogenizer may comprise a delay path which is longer than, but approximately the same delay as the temporal coherence length of the source beam. The homogenizer may comprise a pair of conjoined dove prisms having a partially reflective coating at the conjoined surfaces of each, a right triangle prism comprising a hypotenuse face facing the source beam and fully reflective adjoining side faces or an isosceles triangle prism having a face facing the source beam and fully reflective adjoining side faces or combinations of these, which may serve as a source beam multiple alternating inverted image creating mechanism. The beam path may be part of a bandwidth measuring the bandwidths of an output laser beam comprising output laser light in the range of below 500 femtometers at accuracies within tens of femtometers. The homogenizer may comprise a rotating diffuser which may be a ground glass diffuser which may also be etched. The wavemeter may also comprise a collimator in the beam path collimating the diffused light; a confocal etalon creating an output based upon the collimated light entering the confocal etalon; and a detector detecting the output of the confocal etalon and may also comprise a scanning mechanism scanning the angle of incidence of the collimated light entering the confocal etalon which may scan the collimated light across the confocal etalon or scan the etalon across the collimated light, and may comprise an acousto-optical scanner. The confocal etalon may have a free spectral range approximately equal to the E95 width of the beam being measured. The detector may comprise a photomultiplier detecting an intensity pattern of the output of the confocal etalon.

A cylindrical lens array cannot be manufactured so that each cylindrical lens has the same radius of curvature and the same accuracy in the surface. Therefore, when the laser annealing is performed using the cylindrical lens array, the beam spots divided by the cylindrical lens array cannot be superposed completely in the same surface. As a result, there is a region where the energy is attenuated in the edge portion of the rectangular beam to be formed, and therefore the intensity distribution of the laser beam becomes inhomogeneous. In the present invention, the cylindrical lens array is used in combination with the optical waveguide. After dividing the laser beam in a predetermined direction by the cylindrical lens array, the divided beams are combined, and then the laser beam is incident into the optical waveguide that acts upon the same direction as the predetermined direction. This can correct the variation in the intensity of the laser beam due to the processing inaccuracy of the cylindrical lens array.

The present invention provides a beam homogenizer being equipped with an optical waveguide having a pair of reflection planes provided oppositely, having one end surface into which the laser beam is incident, and having the other end surface from which the laser beam is emitted in the optical system for forming the beam spot. The optical waveguide is a circuit being able to keep radiation light in a certain region and to transmit the radiation light in such a way that the energy flow thereof is guided in parallel with an axis of the channel.

The present invention provides a beam homogenizer being able to form a rectangular beam spot having homogeneous energy distribution in a direction of its major axis without using the optical lens requiring to be manufactured with high accuracy. In addition, the present invention provides a laser irradiation apparatus being able to irradiate the laser beam having homogeneous energy distribution in a direction of its major axis. Furthermore, the present invention provides a method for manufacturing a semiconductor device being able to enhance crystallinity in the surface of the substrate and to manufacture TFT with a high operating characteristic. The beam homogenizer, one of the present invention, is to shape the beam spot on the surface to be irradiated into a rectangular spot having an aspect ratio of 10 or more, preferably 100 or more, and comprises an optical waveguide for homogenizing the energy distribution of the rectangular beam spot in the direction of its major axis.

The energy distribution of the beam spot on the irradiated surface changes due to the change in the oscillation condition of the laser or before and after the maintenance. The present invention provides an optical system for forming a rectangular beam spot on an irradiated surface including a beam homogenizer for homogenizing the energy distribution of the rectangular beam spot on the irradiated surface in a direction of its long or short side. The beam homogenizer includes an optical element having a pair of reflection planes provided oppositely for reflecting the laser beam in the direction where the energy distribution is homogenized and having a curved shape in its entrance surface. The entrance surface of the optical element means a surface of the optical element where the laser beam is incident first.

An optical pulse extender includes a delay loop formed by a plurality of mirrors and a graded reflectivity beamsplitter. The mirrors and the beamsplitter are configured and aligned such that a pulse to be broadened makes a predetermined number of round trips in the delay loop and is incident on a different zone of the beamsplitter after each round trip. The different zones of the beamsplitter have different reflection values and different transmission values. These values are selected such that the pulse extender delivers a plurality of temporally and spatially separated replica pulses each thereof having about the same energy. The delivered replica pulses together provide an extended pulse having a longer duration than the input pulse. The replica pulses may be passed through a beam homogenizer to spatially homogenize the temporal characteristics of the extended pulse.

A means of achieving a spatially uniform output beam from a laser diode array with minimal design complexity is provided. The means is comprised of one or more optical elements located adjacent to the output of the diode array, the optical element(s) reducing the divergence of the output of the individual emitters of the diode array in at least one axis to within an acceptable range, preferably within the range of 0.1 to 10 degrees. The means is further comprised of a diffusing element, the output of the emitters passing through the optical element(s) prior to passing through the diffusing element. The diffusing element, preferably either a holographic diffuser or an engineered diffuser™ which provides control over the light diffusion angles, smoothes out the ripples formed by the overlapping output beams of the emitters in order to achieve the desired spatially uniform beam.

A projection system having a prescribed relationship between the condenser and the projection lens is disclosed, where an imager gate normally coinciding with a projection object plane is between and spaced away from a condenser back focal plane and a condenser image plane. The condenser images an extended source onto the condenser image plane. A pixilated panel or film defining a graphic image is located at the imager gate. The magnification of the condenser is chosen so the image of the source is essentially the same size as the pixilated panel. Positioning the imager gate away from the condenser image plane provides blurring of any brightness non-uniformities across the area of the source, providing a relatively uniform illumination pattern whose outer shape matches the shape of the imager gate.

PCT No. PCT/US95/00540 Sec. 371 Date Oct. 15, 1996 Sec. 102(e) Date Oct. 15, 1996 PCT Filed Jan. 23, 1995 PCT Pub. No. WO95/19811 PCT Pub. Date Jul. 27, 1995The invention includes the use of a beam homogenizer (scattering surface) at the input aperture of a tapered optical fiber to avoid hot spots (2) in the tapered section which would otherwise destroy the fiber (10).

A medical laser apparatus with a beam homogenizer for producing a uniform output beam profile. The beam homogenizer comprises a light pipe which expands the laser beam and mixes the laser light through total internal reflection as well as an optical diffuser to provide further control of the intensity distribution of the laser beam.

The inhomogeneous energy distribution at the beam spot on the irradiated surface is caused by a structural problem and processing accuracy of the cylindrical lens array forming an optical system.

According to the present invention, in the optical system for forming a rectangular beam spot, an optical system for homogenizing the energy distribution of the shorter side direction of a rectangular beam spot of a laser light on an irradiated surface is replaced with a light guide. The light guide is a circuit that can confine emitted beams in a certain region and guide and transmit its energy flow in parallel with the axis of a path thereof.

An effect of interference is eliminated and intensity of a laser beam is homogenized. The beam homogenizer 100 includes reflecting mirrors 103 and 104 which are provided so that reflecting surfaces thereof face each other. The laser beam LB propagates through a space between the reflecting mirrors 103 and 104 while being reflected therebetween, so that intensity distribution of the laser beam LB is homogenized, but the laser beam LB also interferes. The first reflecting mirror 103 and the second reflecting mirror 104 are oscillated in a direction perpendicular to a direction in which the laser beam LB is scanned, intensity distribution of the laser beam LB in an oscillation direction is temporally averaged.