Abstract: Devices, systems, and methods are provided for using a light detection and ranging (LIDAR) receiver optical design. A vehicle anamorphic LIDAR system may include a group of rotationally symmetric lenses, a first cylindrical lens, and a second cylindrical lens, wherein the first cylindrical lens is arranged between the group of rotationally symmetric lenses and the second cylindrical lens, wherein the vehicle anamorphic LIDAR system is associated with a first focal length in a first direction associated with a scene field of view, and a second focal length in a second direction perpendicular to the first direction and associated with an instantaneous field of view, and wherein the first focal length is different than the second focal length.

Abstract: An optical fiber splitter device comprising at least two optical fibers of different lengths is disclosed for partial or complete compensation of the optical path difference between waves interfering to generate a hologram or an interferogram. Various implementations of this fiber splitter device are described in apparatuses for holographic and interferometric imaging of microscopic and larger samples.

Abstract: A method for planning a technical system by providing a number of engineering objects in which each engineering object describes a technical component of the technical system, includes types that refer to a function of the engineering object and information about to what which domain of a plurality of domain each type belongs to and includes electrical information that includes a schematic symbol description, an electrical behavior and electrical characteristics, a number of coherence requirements for the technical system are provided, where the coherence requirements include object patterns defining objects of a same kind to be grouped together and a required order of a sequence of the objects in the object patterns, an engineering object is selected, a schematic is generated by placing the schematic symbol description of the selected engineering object and associated engineering objects of an object pattern belonging to the selected engineering object on a plan, and electrical connections between all object

Abstract: The invention relates to optical communication methods and systems. In particular, the invention relates to an optical communication method and system which is configured to create a multiplexed beam from an incident beam, wherein the multiplexed beam comprises a predetermined number of spatial modes simultaneously generated and multiplexed together in a fashion that is independent of wavelength. The spatial modes have two degrees of spatial freedom. The multiplexed beam is de-multiplexed downstream from multiplexing thereof in the communication system in a simultaneous fashion independent of wavelength to yield the predetermined number of spatial mode. The modes are used in optical communication as channels or as bits in a bit (de) encoding scheme.

Abstract: In various embodiments, wavelength beam combining laser systems incorporate etalons to establish external lasing cavities and/or to combine multiple input beams into a single output beam.

Abstract: A frequency swept laser source for TEFD-OCT imaging includes an integrated clock subsystem on the optical bench with the laser source. The clock subsystem generates frequency clock signals as the optical signal is tuned over the scan band. Preferably the laser source further includes a cavity extender in its optical cavity between a tunable filter and gain medium to increase an optical distance between the tunable filter and the gain medium in order to control the location of laser intensity pattern noise. The laser also includes a fiber stub that allows for control over the cavity length while also controlling birefringence in the cavity.

Abstract: High-power, phased-locked, laser arrays as disclosed herein utilize a system of optical elements that may be external to the laser oscillator array. Such an external optical system may achieve mutually coherent operation of all the emitters in a laser array, and coherent combination of the output of all the lasers in the array into a single beam. Such an “external gain harness” system may include: an optical lens/mirror system that mixes the output of all the emitters in the array; a holographic optical element that combines the output of all the lasers in the array, and an output coupler that selects a single path for the combined output and also selects a common operating frequency for all the coupled gain regions.

Abstract: In various embodiments, wavelength beam combining laser systems incorporate optics having optical power along the non-WBC direction (and/or the slow-diverging axis) of the combined multi-wavelength beam proximate to or combined with the partially reflective output coupler in order to correct pointing variation in the non-WBC direction (and/or the slow-diverging axis).

Abstract: A wavelength tunable silicon-on-insulator (SOI) laser comprising: a laser cavity including: a semiconductor gain medium having a front end and a back end, wherein a mirror of the laser cavity is located at the back end of the semiconductor gain medium; and a phase-tunable waveguide platform coupled to the front end of the semiconductor gain medium, the phase-tunable waveguide platform comprising: a first resonator and a second resonator; at least one resonator being a phase-tunable resonator; wherein the first resonator is any one of: an MMI device including a pair of reflective surfaces defining a resonator cavity therebetween such that the device is configured to act as a Fabry-Perot filter; a ring resonator; or a waveguide Fabry-Perot filter; and wherein the second resonator is any one of: an MMI device including a pair of reflective surfaces defining a resonator cavity therebetween such that the device is configured to act as a Fabry-Perot filter; a ring resonator; or a waveguide Fabry-Perot filter.

Abstract: A method for the production of a holographic sensor which comprises a support medium supporting a reflection hologram wherein the support medium interacts with its physical or chemical environment to create an optical response which is a change in one or more optical properties of the hologram, the method comprising the steps of: a) introducing a colloidal dispersion of a recording material into the support medium; and b) ablating the colloidal particles of the recording material using a pulsed laser to form the holographic element in the support medium. The method of production can be used to introduce a reflection holographic grating into a hydrophobic support medium, in particular, polydimethylsiloxane (PDMS), which possesses an extraordinary ability to swell in the presence of both liquid and/or gaseous low molecular weight hydrocarbons and organic solvents and thus has many applications as a holographic sensor.

Abstract: Laser apparatus includes an output coupler, a gain medium for generating laser light, a rear optical element, and an input coupler. The input coupler is arranged to direct a pump beam to the gain medium and to define an optical path between the output coupler and the rear optical element. The rear optical element is a spatial light modulator arranged to act as an intra-cavity digital holographic mirror which can be digitally addressed. The spatial light modulator displays selectively a gray-scale image of a hologram thereby to phase-modulate laser light in the cavity, thus making it possible to generate an output laser beam having a desired characteristic. The apparatus includes a computer arranged to generate at least one hologram corresponding to a desired output beam characteristic, and a driver circuit responsive to an output from the computer to generate a corresponding gray-scale image of the hologram on the spatial light modulator.

Abstract: A laser device includes a pump source, a ring resonator, a gain medium disposed in the ring resonator, and a holographic output coupler to partially transmit the laser radiation. The gain medium is configured to receive radiation from the pump source and generate laser radiation.

Abstract: This disclosure provides systems, methods and apparatus, including a display device that includes an overlying holographic film. In one aspect, the holographic film includes a hologram that is configured to turn light incident on the film. The light is turned towards the display device at desired angles. The display can be formed of interferometric modulators and the turned light can be reflected off the display, and towards a viewer, to form an image. For light that is incident on the film at angles outside of a view cone, the holographic film is provided with holographic light turning features that turn this light so that it is reflected off the display at angles within a view cone of the display.

Abstract: In the conventional contaminant particle/defect inspection method, if the illuminance of the illumination beam is held at not more than a predetermined upper limit value not to give thermal damage to the sample, the detection sensitivity and the inspection speed being in the tradeoff relation with each other, it is very difficult to improve one of the detection sensitivity and the inspection speed without sacrificing the other or improve both at the same time. The invention provides an improved optical inspection method and an improved optical inspection apparatus, in which a pulse laser is used as a light source, and a laser beam flux is split into a plurality of laser beam fluxes which are given different time delay to form a plurality of illumination spots. The scattered light signal from each illumination spot is isolated and detected by using a light emission start timing signal for each illumination spot.

Abstract: A substrate includes a diffracting structure providing a hologram (20, 6). The diffracting structure encodes a holographic image so that thatholographic image is produced in response to reference light being incident on a major surface of the substrate at an angle of incidence with respect to the said major surface of the substrate, wherein the angle of incidence is no more than 20°.

Abstract: Methods and systems for a compressive optical display and imager using optical scanning and selection and three-dimensional beamforming optics. Standard pixel data can generate a compressed image data set having custom pixel sizes, locations, and intensities. A 3-D beamformer optic adjusts its focus to produce the largest focused beam spot on the display screen corresponding to an image zone compressed pixel. Using scan mirror angular controls, display image space is painted using minimal numbers of laser beam spots whose sizes depend on the compressed sensed image. The imager includes movable reflecting optics to reflect an optical image and controllable imaging optics to pass the reflected optical image toward a digital micromirror that reflects +/?? optical beams into +/? ? optical beam paths. A controller controls reflecting optics and agile front end imaging optics to receive an electronic image signal corresponding to detected +/?? optical beams.

Abstract: High-power, phased-locked, laser arrays as disclosed herein utilize a system of optical elements that may be external to the laser oscillator array. Such an external optical system may achieve mutually coherent operation of all the emitters in a laser array, and coherent combination of the output of all the lasers in the array into a single beam. Such an “external gain harness” system may include: an optical lens/mirror system that mixes the output of all the emitters in the array; a holographic optical element that combines the output of all the lasers in the array, and an output coupler that selects a single path for the combined output and also selects a common operating frequency for all the coupled gain regions.

Abstract: In one implementation, a system includes a multi-core processor and an optical display with a plurality of hogels. Each hogel is configured to radiate light in a plurality of directions, with controllable intensities in each of the plurality of directions. The multi-core processor is coupled to the optical display and configured to control the hogels. The multi-core processor includes at least two cores, an on-chip memory, and a master processor in a single integrated circuit package. The master processor may be a general-purpose on-chip processor, such as a core in the multi-core processor, that is used to coordinated operations of the other cores. Each of the cores is configured to receive hogel data and to generate signals for a corresponding subset of the plurality of hogels.

Abstract: Exemplary embodiments provide methods for patterning large areas, beyond those accessible with the limited single-area exposure techniques, with nanometer scale features. The methods can include forming a grating pattern to make a first interferometric exposure of a first portion of a photosensitive material disposed over a substrate by interfering two or more laser beams, wherein the two or more laser beams comprise an apodized intensity profile having a continuous intensity variation. The method can further include aligning and overlapping the grating pattern to expose a second portion of the photosensitive material such that the first portion and the second portion form a continuous grating pattern.

Abstract: A method and a device for scanning-microscopy imaging of a specimen (28) are described. Provision is made that a plurality of specimen points are scanned by means of a scanning beam (14) in successive scanning time intervals, the intensity of the radiation emitted from the respectively scanned specimen point is repeatedly sensed within the associated scanning time interval, an intensity mean value is determined, as a mean value image point signal, from the intensities sensed in the respectively scanned specimen point, and the mean value image point signals are assembled into a mean value raster image. Provision is further made for additionally determining an intensity variance value, as a variance image point signal, from the intensities sensed in the respectively scanning specimen points, and for assembling the variance image point signals into a variance raster image signal.

Abstract: A laser detection method and apparatus for detection of laser beams can each perform operations for producing an interference image from detected light radiation, recording the interference image, and processing the recorded interference image in order to detect laser radiation. In order to allow more robust and faster laser detection, the apparatus and method can detect a spatially defined point distribution from the interference image, and transform the point distribution such that a grid interval remains between a point grid in the point distribution, and a fixed position, which is independent of a position in the original image, is associated with the point grid. The apparatus and method can further detect a grid interval in the point grid that was transformed, and detect the position of the point grid from the point distribution by filtering with the assistance of the grid interval.

Abstract: An apparatus for reading and writing holograms from and to a holographic storage medium uses an object beam and a reference beam both having a first coherence length and being guided along separate optical branches of an optical setup to be imaged to the holographic storage medium. The apparatus includes one or more elements for reducing the coherence length of the reference beam to a second coherence length for reading out a hologram from the holographic storage medium, wherein the second coherence length is shorter than the first coherence length.

Abstract: A wavelength combining apparatus includes first and second optical devices. The first optical device collects and collimates or focuses light from multiple laser light sources. The second optical device includes multiple nonparallel dichroic surfaces to combine light received from the first optical device.

Abstract: Included are a semiconductor device unit in which a semiconductor optical amplifier and a first semiconductor photo detector being configured to monitor a part of an input light input to the semiconductor optical amplifier or a part of an output light output from the semiconductor optical amplifier are integrated on a mutually same substrate, and a passive waveguide unit connected to the semiconductor device unit and in which a first passive waveguide being configured to cause the input light to be input to the semiconductor optical amplifier or to cause the output light to be output from the semiconductor optical amplifier and a second passive waveguide branching from the first passive waveguide and being configured to cause a part of the input light or a part of the output light to be input to the first semiconductor photo detector are provided on a mutually same substrate.

Abstract: High-power, phased-locked, laser arrays as disclosed herein utilize a system of optical elements that may be external to the laser oscillator array. Such an external optical system may achieve mutually coherent operation of all the emitters in a laser array, and coherent combination of the output of all the lasers in the array into a single beam. Such an “external gain harness” system may include: an optical lens/mirror system that mixes the output of all the emitters in the array; a holographic optical element that combines the output of all the lasers in the array, and an output coupler that selects a single path for the combined output and also selects a common operating frequency for all the coupled gain regions.

Abstract: A module 1 movable over the original surface 110 of the original reader 100 has a metal sheet frame 4 disposed in the vicinity of its gravitational center and having a substantially channel-like shape. A first and a second optical systems 2 and 3 and a drive source 6 assembled to be integral with a flat part 40 of the metal sheet frame 4. Thus, a reduced-size, improved quality and improved-accuracy original reader to be used for facsimile devices and image scanners is obtained.

Abstract: A holographic reconstruction system and method for the three-dimensional reconstruction of object light points of a scene. The system includes spatial light modulation means which modulate light waves capable of interference with at least one video hologram, focusing means which focus the modulated light waves so that a viewer can view the reconstructed object light points of the scene from a visibility region that is thereby produced by focusing, and deflection means which position the visibility region by aligning the modulated light waves. The holographic reconstruction system includes deflection control means for controlling the deflection means to sequentially adjust the visibility region to different contiguous viewing positions, and light controlling means for switching the light waves in synchronicity with the deflection control means.

Abstract: An image projector having one or more broadband lasers designed to reduce the appearance of speckle in the projected image via wavelength diversification. In one embodiment, a broadband laser has an active optical element and a nonlinear optical element, both located inside a laser cavity. The broadband laser generates an output spectrum characterized by a spectral spread of about 10 nm and having a plurality of spectral lines corresponding to different spatial modes of the cavity. Different individual spectral lines effectively produce independent speckle configurations, which become intensity-superimposed in the projected image, thereby causing a corresponding speckle-contrast reduction.

Abstract: Compositions capable of simultaneous two-photon absorption and higher order absorptivities are provided. Compounds having a donor-pi-donor or acceptor-pi-acceptor structure are of particular interest, where the donor is an electron donating group, acceptor is an electron accepting group, and pi is a pi bridge linking the donor and/or acceptor groups. The pi bridge may additionally be substituted with electron donating or withdrawing groups to alter the absorptive wavelength of the structure. Also disclosed are methods of generating an excited state of such compounds through optical stimulation with light using simultaneous absorption of photons of energies individually insufficient to achieve an excited state of the compound, but capable of doing so upon simultaneous absorption of two or more such photons. Applications employing such methods are also provided, including controlled polymerization achieved through focusing of the light source(s) used.

Abstract: A solid-state imaging device includes: a pixel portion configured to convert light into an electric signal; a substrate where the pixel portion is formed; an optical communication unit configured to convert a signal read out from the pixel portion into an optical signal, and outputs the optical signal, which is disposed in one surface where the pixel portion is formed of the substrate; and a light shielding portion configured to shield, of signal light to be output from the optical communication unit, light that directs to the pixel portion, and light to be leaked from the optical communication unit, which is disposed around the optical communication unit.

Abstract: A optical apparatus (201) for use in an laser imaging system (200) is provided. The optical apparatus (201) includes one or more optical elements (215) that are configured to create an intermediate image plane (217) in the laser imaging system (200). A diffractive optical element (216) is then disposed at the intermediate image plane (217) to reduce speckle. The diffractive optical element (216) includes a periodically repeating phase mask (218) that can be configured in accordance with steps, vortex functions, Hermite-Gaussian functions, and so forth. Smooth grey-level phase transitional surface (337) can be placed between elements (333,334) to improve brightness and image quality. The periodically repeating phase mask (218) makes manufacture simple by reducing alignment sensitivity, and can be used to make applicable safety standards easier to meet as well.

Abstract: A laser device includes a pump source, a ring resonator, a gain medium disposed in the ring resonator, and a holographic output coupler to partially transmit the laser radiation. The gain medium is configured to receive radiation from the pump source and generate laser radiation.

Abstract: A card authentication is performed. An authentication chip for performing authentication by a copy-disabled hologram chip is attached to a card and when or after the card is introduced into a handling device, the authentication chip information is read to perform authentication. Read may be performed in a planar shape but a linear shape can reduce the processing load. An arbitrary straight line or a curved line may be used as a read line shape by modifying the read position in association with the card movement when the card is placed to be read. When the card introduced to a terminal device is an unauthorized one, the card is ejected or an alarm is issued when the card is introduced inside.

Abstract: Non-rigidly coupled, overlapping, non-feedback optical systems for spatial filtering of Fourier transform optical patterns and image shape characterization comprises a first optical subsystem that includes a lens for focusing a polarized, coherent beam to a focal point, an image input device that spatially modulates phase positioned between the lens and the focal point, and a spatial filter at the Fourier transform pattern, and a second optical subsystem overlapping the first optical subsystem includes a projection lens and a detector. The second optical subsystem is optically coupled to the first optical subsystem.

Abstract: An image generating apparatus is provided, which has a plurality of image generating optical paths and means for simultaneously deflecting a received plurality of light beams of primary illumination light having coherence properties. The received light beams are assigned to the respective optical paths. The means for deflecting simultaneously optically couples each of the received light beams into a respective assigned optical path and irradiates intermediate faces of illumination units of each respective optical path with the respective assigned light beam. The means for deflecting is configured so that, during the process of irradiating, each of the light beams subsequently in time irradiates different portions of the respective assigned intermediate faces.

Abstract: High-power, phased-locked, laser arrays as disclosed herein utilize a system of optical elements that may be external to the laser oscillator array. Such an external optical system may achieve mutually coherent operation of all the emitters in a laser array, and coherent combination of the output of all the lasers in the array into a single beam. Such an “external gain harness” system may include: an optical lens/mirror system that mixes the output of all the emitters in the array; a holographic optical element that combines the output of all the lasers in the array, and an output coupler that selects a single path for the combined output and also selects a common operating frequency for all the coupled gain regions.

Abstract: An apparatus for producing a duplicate hologram recording medium includes: a positioning section configured to place the duplication master and the duplicate hologram recording medium at predetermined relative positions; an angle selective plate arranged between the duplication master and the duplicate hologram recording medium, the angle selective plate having an angle selective film whose transmittance changes in accordance with an incidence angle of a light beam; and a duplicating-reference-beam generating and radiating section generating a duplicating reference beam, and radiating the duplicating reference beam at such an incidence angle that the duplicating reference beam is transmitted through a predetermined region of a recording layer of the duplication master and is reflected by the angle selective film.

Abstract: The present invention provides a planar lighting device (1) including: a laser light source (12) which emits a linearly-polarized laser beam; an optical member (13) which receives the laser beam, then parallelize the laser beam, and emits the parallelized laser beam; and a first plate-shaped light guide (20) which receives the parallelized laser beam from an end face portion (20d) and emits the parallelized laser beam from a first major surface (20b). The first light guide includes an optical element (20a) which receives the linearly-polarized parallelized laser beam propagated through the first light guide and emits at least a part of the linearly-polarized parallelized laser beam in a direction substantially vertical to the first major surface. The present invention also provides a liquid crystal display device (3) using the planar lighting device (1) as a backlight lighting device.

Abstract: A system for making small modifications to the pattern in standard processed semiconductor devices. The modifications are made to create a small variable part of the pattern against a large constant part of the same pattern. In a preferred embodiment the exposure of the variable and constant parts are done with the same wavelength in the same combined stepper and code-writer. The invention devices a way of writing variable parts of the chip that is automatic, inexpensive and risk-free. A system for automatic design and production of die-unique patterns is also shown.

Abstract: A pulsed multiple colour laser system is disclosed having particular application for incorporation into a digital holographic printer for producing RGB colour reflection holograms. A Nd:YLF crystal 1 in a laser cavity is excited to produce an emission at 1313 nm which is frequency converted by doubling to 656.5 nm and by tripling to 437.7 nm. In a separate cavity a similar Nd:YLF crystal 1a is synchronously or asynchronously excited to produce an emission at 1047.1 nm (or at the related line of 1053 nm) which is frequency converted by doubling to 523.6 nm (or 526.5 nm). The emissions at 437.7 nm and 656.5 nm are combined co-linearly with the emission at 523.6 nm (or 526.5 nm) to produce a single RGB pulsed laser beam.

Abstract: An optical system (20) for efficiently collimating an elliptical light beam includes a light source (21), a first lens (22), a second lens (23), and a third lens (24). The light source is adapted for providing an elliptical light beam defining different diverging angles in different directions, wherein any cross-section of the elliptical light beam emitted from the light source defines a long axis and a short axis which are perpendicular to each other. The first lens, the second lens, and the third lens are used for reconfiguring the elliptical light beam, thus obtaining a round light beam having equivalent short axis and long axis, and equivalent diverging angles in both horizontal direction and vertical direction. Optical centers of the first lens, the second lens, and the third lens commonly define a common optical axis along which the elliptical light beams travels.

Abstract: In a method for production of documents with a hologram and a document with a hologram, wherein, in a first step, a hologram is exposed in a photographic film and, in a second step, the photographic film is applied to a document support, the individualisation of the holograms first occurs during the gluing or after the gluing to the printed personal document or to the protective film provided for the surface protection of the document. It is thus possible to produce in a secure and economical fashion documents with individual holographic information of greater visibility and with further novel security features.

Abstract: Provided are an illumination system capable of eliminating laser speckle and a projection system employing the illumination system. The illumination system includes a laser light source having at least one laser, and a first diffractive optical element to divide a laser beam emitted from the laser light source into a plurality of partial beams and to time-average the partial beams through a periodical movement to eliminate speckle. Accordingly, the illumination system can eliminate speckle of the beams emitted from the laser light source and the projection system employing the illumination system can achieve a high quality image.

Abstract: A light show device includes a light source configured to generate a light beam having a substantially constant diameter, a container having a substantially transparent portion, a plurality of mirrors, each mirror connectable or connected to the container rotatably about at least one axis, and a particulate source configured to create inside the container a substantial suspension of particulates, where the device is configured to allow a reflection of the light beam between at least a majority of the mirrors.

Abstract: A laser projection device suitable for displaying full color images is disclosed. The LPD includes a variety of techniques for modulating laser beams produced by one or more lasers with image data to controllably produce the image using a modified raster scan.

Abstract: A method and arrangement for producing a hologram of an object uses light, having photon packets, to illuminate the object and to serve as a reference light. Each photon packet includes a plurality of photons correlated in a quantum-mechanical manner and jointly form a multi-photon Fock state. Some of the photon packets may be used for illuminating the object, and some may be used as a reference light. Photon packets arriving from the object may be made to interfere with the reference light in an interference field, and the brightness distribution in the interference field or a part thereof may be registered by a detector. A light source emitting a plurality of mutually coherent rays of photon packets may be used for generating the packets, some of the rays being used for illuminating the object, and some of the rays being used as a reference light or for forming same.

Abstract: The exposure amounts of R, G, and B laser light emitted from a fabrication light source are so adjusted that the diffraction efficiency at R, G, and B wavelengths in an optical element is commensurate with the light intensity at the R, G, and B wavelengths in the light emitted from a reproduction light source. For example, when the light intensity of the light emitted from the reproduction light source is increasingly low at the B, G, and R wavelengths in this order, the exposure amounts of the R, G, B, laser light emitted from the fabrication light source are so adjusted that the diffraction efficiency in the optical element is increasingly high at the B, G, and R wavelengths in this order. In this way, the hue of the light (reproduction light) obtained from the reproduction light source via the optical element can be adjusted to the hue desired with every reproduction light source used, while the most use is made of the light emitted from the reproduction light source actually used.

Abstract: Described is an optical device for combining multiple light sources in an optical projection system. One embodiment of the optical device includes at least two light sources having first and second wavelengths, and an optical element for substantially diffracting the first and second wavelengths of the two light sources and combining them into a single beam of light.

Abstract: Disclosed is a method of producing a hologram through a two-beam laser interfering exposure process, which comprises emitting a coherent laser light with a pulse width (?) ranging from greater than 900 femtoseconds to 100 picoseconds and a laser power of 10 ?J/pulse or more using a solid-state laser as a light source, dividing the pulses light from the laser into two beams, controlling the two beams temporally and spatially in such a manner that the two beam are converged on a surface of or inside a workpiece for recording a hologram while matching the respective converged spots of the two beams with one another temporally and spatially to create the interference therebetween so as to record a surface-relief hologram on the surface of the workpiece or an embedded hologram inside the workpiece in an irreversible manner.

Abstract: A reflection-type laser projector (100) projects modulated laser beams outputted from a laser projection unit (40), on a screen, wherein a reflector (112) as a constituent of the screen (110) has reflection characteristics of reflecting, among the incident light, only laser beams of three colors of red, blue, and green, which are projected from the laser projection unit (40) and light in the neighboring wavelength band, and transmitting light in other wavelength bands, thereby preventing pictures on the screen (110) from becoming hard to be seen due to effects of indoor illumination or light from outdoors.