33results about How to "Speckle suppression" patented technology

The invention discloses a device and method for inhibiting laser speckles and a laser display projection system. The device comprises a plurality of noncoherent lasers, an optical fiber coupler and an optical fiber bundle. Multiple paths of light beams output by the lasers are coupled into sub optical fibers of the optical fiber bundle through the optical fiber coupler. The light beams transmitted in the sub optical fibers are called sub light beams. The adjacent sub light beams of the same frequency output by the output end of the optical fiber bundle have the preset distance in space. The sub light beams of the same frequency irradiate a screen at different angles through a projection system due to the set preset distance, so that speckle patterns observed by human eyes are independent from one another. According to the device, the coherence of the light beams is lowered through the noncoherent lasers, and thus the speckle contrast is lowered; the sub light beams are distributed according to the angle diversification of the speckles at the output end of the optical fiber bundle, and the independent speckles are superposed in the space to lower the speckle contrast; the speckle inhibiting effects of the two methods can be superposed, and the speckle contrast is lowered to a greater extent.

To provide an illumination device and a projection type image display device that illuminate an area to be illuminated (image formation area) under conditions where speckle noise is less noticeable.

An illumination device according to the present invention includes: a light source 11 that emits coherent light; an optical scanning section 15 that scans the coherent light emitted from the light source 11; and an optical path conversion system 21 configured to allow the coherent light scanned by the optical scanning section 15 to illuminate an area to be illuminated sequentially in an overlapping manner. An incident angle of the coherent light that enters respective points of the area to be illuminated changes with time.

A method and apparatus for printing a pattern of periodic features into a photosensitive layer, including the steps of providing a substrate bearing the layer, providing a mask, arranging the substrate such that it has a tilt angle with respect to the substrate in a first plane orthogonal thereto, providing collimated light for illuminating the mask pattern so as to generate a transmitted light-field composed of a range of transversal intensity distributions between Talbot planes separated by a Talbot distance, and so that said transmitted light-field has an intensity envelope in the first plane, illuminating the mask with said light whilst displacing the substrate relative to the mask in a direction parallel to the first plane and to the substrate, wherein the tilt angle and the intensity envelope are arranged so that the layer is exposed to an average of the range of transversal intensity distributions.

The invention discloses a low-coherence chaotic laser for laser display and relates to the field of light sources for laser display. The laser mainly comprises a TO package laser housing having threepins at the outer side. A laser chip is fixed to a support frame in the TO package laser housing. A cemented lens is fixed to the light-emitting window of the TO package laser housing and is formed bycombining a collimating lens and a transflective lens which are successively placed along an optical path and are fixed in such a way of clinging to each other. The contact inner sides of the collimating lens and the transflective lens are plated with a transflective film. The laser exit center of the laser chip is located at the focal length of the collimating lens. A laser beam is collimated bythe collimating lens and then passes through the transflective lens. The transflective film on the transflective lens transmits a part of the laser beam, and reflects the other part of the laser beamback to the laser chip. Thus, a feedback is provided for the laser chip to form a chaotic laser, thereby reducing the coherence of the laser, achieving speckle suppression, and facilitating the structure optimization and integration of a laser display system.

A beam modulated by a video signal scans a projected region. A spot size of the beam in the projected region is set to be smaller than a width of one pixel in a direction vertical to a scanning direction. A group of pixels disposed in the scanning direction is scanned by the beam a plurality of times to display one screen. A scanning position of the beam with regard to the group of the pixels is shifted in the direction vertical to the scanning direction for every scanning turn to display one screen.

The invention discloses a radar image spot noise suppression method based on the correlation loss convolutional neural network. The method comprises steps that a radar image is inputted into the trained convolutional neural network to obtain the spot noise suppression result image; the training method of the convolutional neural network includes steps that spot noise is superimposed to a remote sensing image to obtain the image after spot noise superimposition, and the image after spot noise superimposition is inputted into the convolutional neural network to obtain a training output image; error loss is obtained according to a mean square error of the remote sensing image and the training output image, and correlation loss is obtained through utilizing a correlation coefficient between the remote sensing image and the training output image; reverse propagation is performed through utilizing the error loss and the correlation loss, and weight parameters of the convolutional neural network are updated; the trained convolutional neural network is obtained. The method is advantaged in that the error loss and the correlation loss are utilized, the weight parameters of the convolutionalneural network are updated, and thereby the radar image spot noise suppression effect of the network is effectively improved.

The invention discloses a three-dimensional morphology measurement method for inhibiting speckles on the basis of wide-spectrum laser. The method comprises the following steps: a step of outputting a wide-spectrum laser source to the surface of a measured object for scanning; a step of extracting center point pixel coordinates of light spots of scanned images; and a step of converting the center point pixel coordinates to obtain three-dimensional point-cloud data of the measured object. According to the method, the wide-spectrum light source is output when a laser is at a coherent collapse state, for carrying out accurate three-dimensional surface morphology measurement, such that the speckles are effectively inhibited from a hardware perspective, the technical problem that high-frequency useful information in the images are filtered is solved, the image sharpness is improved, and the application field is wide.

An embodiment of the invention relates to the technical field of semiconductor lasers, and more particularly to a semiconductor laser driving method and driving circuit for solving the problems of complicated structure and high cost as a speckle eliminating device is added mostly outside a laser in the prior art. In the embodiment of the invention, driving signals are generated in accordance with driving periods of a semiconductor laser, one driving period includes a high level duration segment and a low level duration segment, and driving signals in the high level duration segment of one driving period are composed of N pulses, where N is an integer greater than one; peak values of at least two of the N pulses are not equal, and/or at least two pulse intervals in N-1 pulse intervals formed by the N pulses are not equal; and the driving signals are outputted to the semiconductor laser. Therefore, the speckle suppression or elimination can be performed without the addition of a speckle eliminating device, and the structural complexity is reduced.

The invention discloses a laser light source device, a projection system and a control method of the projection system. According to the device, a laser beam is coupled into a multimode optical fiberfor transmission by adopting an optical coupling component, and the laser beam passing through the multimode optical fiber can generate random propagation time change, so that the time coherence of the laser is destroyed; then the laser beam passing through the multimode optical fiber enters an electro-refractive index changing component again, and a control signal is applied to the electro-refractive index changing component, so that the refractive index of a medium at the incident position of the laser beam is changed, and a spatial phase difference is generated at different positions by a light spot when the laser is emitted so as to reduce the spatial coherence of the laser; and the laser beam passing through the electro-refractive index changing component is incident to a light homogenizing component to further homogenize the laser beam. According to the laser light source device provided by the embodiment of the invention, the time and space coherence of the laser can be reducedat the same time, and speckles generated by the laser are effectively inhibited.

The invention provides a static laser speckle reduction method combining a multimode optical waveguide and a diffractive optical device. The method comprises the following steps that Step 1, a laser beam is collimated and then input into the diffractive optical device, the diffractive optical device outputs the incident collimated laser beam as diffraction beams with different diffraction orders;Step 2, the diffraction beams with the different diffraction orders are focused by a lens, the focused beams are input into the multimode optical waveguide, the multimode optical waveguide modulates the transmission delay of different diffracted beams, so that the diffraction beams of all diffraction orders are output from the multimode optical waveguide at the delay difference delta T; Step 3, the diffraction beams output at different delays are collected by an imaging lens and imaged on a projection screen, the projection screen is provided with a rough surface, an image on the projection screen is received and processed by a digital camera, and the static laser speckle suppression is achieved. The static laser speckle reduction method combining the multimode optical waveguide and the diffractive optical device has the advantages that the reliability is high, electric energy supply is not needed, the response time is short, no mechanical running mechanism is needed, the system is simple, the size is small, and the cost is low.

The invention discloses an optical measuring system based on an integrating sphere. The system comprises an incident laser, a beam narrowing mirror, the integrating sphere, an energy meter, a photoelectric tube, a fiber coupler, a computer, an oscilloscope and a spectrometer. The integrating sphere is provided with a light in port and three light out ports. The beam narrowing mirror is arranged atthe light in port, and the energy meter, the photoelectric tube and the fiber coupler are arranged at the three light out ports. An output end of the energy meter is connected to the computer, and anoutput end of the photoelectric tube is connected to the oscilloscope. An output end of the fiber coupler is connected with to spectrometer, an inner wall of the integrating sphere is coated with a diffuse reflection coating, and at the same time, a diffuse reflection plate is arranged on the inner wall of the integrating sphere. A micro DC motor is mounted outside an integrating sphere shell, and a rotor of the micro DC motor passes through the integrating sphere shell to connect the diffuse reflection plate. When the system is applied, the energy parameters, time parameters and spectral parameters of the laser can be measured synchronously, the laser speckle can be effectively suppressed, the parameter measurement accuracy can be improved, and the manufacturing cost can be reduced.

The invention provides a speckle suppression device based on frustrated total internal reflection light splitting. The speckle suppression device comprises a first glass substrate, a patterned nano film, a bonding layer, a spacer, a second glass substrate and a Dove prism. A beam of laser enters the speckle suppression device through the Dove prism, is transmitted for multiple times through the first glass substrate and the bonding layer and is totally reflected for multiple times through the second glass substrate, a frustrated total internal reflection phenomenon occurs on the patterned nano-film, and finally a group of incoherent emergent laser beams with the same light intensity are formed, and the purposes of destroying laser coherence and inhibiting speckles are achieved. Compared with the prior art, the speckle suppression device provided by the invention has the advantages of zero power consumption, static state, small size and the like.

The invention discloses a laser speckle suppression element and a suppression method, which are used for improving the speckle suppression efficiency and enhancing the speckle suppression effect. Theelement is made of a light-transmitting material and comprises an array formed by a plurality of light-transmitting areas; the transverse size of the light-transmitting area is smaller than the spatial resolution of human eyes; the difference value of the longitudinal sizes of the adjacent light-transmitting areas enables the optical path difference of the laser beams penetrating through the adjacent light-transmitting areas to be not smaller than the coherence length of the laser beams; thus, the time coherence between the adjacent sub laser beams can be destroyed, the spatial coherence of the laser can be destroyed, the adjacent sub laser beams become non-correlated light, spatial superposition of multiple independent speckles can be achieved within the resolution of human eyes, and effective inhibition of the speckles is achieved.