Abstract: A light emitting device includes: a base having an upper face; a light emitting element mounted on the upper face of the base; one or more bonding members disposed on the upper face of the base outward of the light emitting element; a light transmissive member bonded to a portion of the upper face of the base by the one or more bonding members; and a protective film that continuously covers the light emitting element, the upper face of the base, lateral faces of the one or more bonding members, and a lower face of the light transmissive member. A gap is located between the upper face of the base and the lower face of the light transmissive member and configured to allow a space in which the light emitting element is mounted to communicate with an outside of the light emitting device, wherein the gap is defined by the upper face of the base, the lower face of the light transmissive member, and the one or more bonding members.

Abstract: The present disclosure provides a glass plate including a main surface having a plurality of minute deformed portions which are recesses or projections, wherein, where an average value of lengths of two sides adjacent to each other of a minimum quadrilateral with four right angles surrounding each minute deformed portion is defined as a dimension, an average value of the dimensions of the plurality of deformed portions is 3.2 to 35.5 ?m. The glass plate satisfies a condition a1 that a ratio of deformed portions A1 having the dimensions of 0.5 to 3.0 ?m with respect to the plurality of deformed portions in terms of number is less than 5%, and/or a condition d1 that a coefficient of variation of the dimensions is 40% or less. This glass plate is suitable for suppressing sparkle and is highly practical, when disposed on an image display device.

Abstract: A light-emitting element includes: a first electrode serving as an anode; a second electrode serving as a cathode; a light-emitting layer, of a first wavelength range, provided between the first electrode and the second electrode; an oxide layer provided between the light-emitting layer of the first wavelength range and the first electrode of the first electrode and the second electrode; and an oxide layer provided between the oxide layer and the second electrode, and having contact with the oxide layer. Either the oxide layer or the oxide layer whichever farther away from the light-emitting layer of the first wavelength range is made of a semiconductor. A density of oxygen atoms in the oxide layer is lower than a density of oxygen atoms in the oxide layer.

Abstract: An electronic device is provided. The electronic device includes a panel and an optical element. The optical element is disposed on the panel. The optical element includes a first surface away from the panel. The first surface has a microstructure, and the microstructure has an arithmetical mean deviation of the profile (Ra). The optical element has a thickness. In addition, the arithmetical mean deviation of the profile (Ra) and the thickness conform to the following formula: 0.00001?arithmetical mean deviation of the profile/thickness?0.0104.

Abstract: A particularly-formed multi-layer micron-sized particle is provided that is substantially transparent, yet that exhibits selectable coloration based on its physical properties. The disclosed physical properties of the particle are controllably selectable refractive indices to provide an opaque-appearing energy transmissive material when pluralities of the particles are suspended in a substantially transparent matrix material. Multiply-layered (up to 30+ constituent layers) particles result in an overall particle diameter of less than 5 microns. The material suspensions render the particles deliverable as aspirated or aerosol compositions onto substrates to form layers that selectively scatter specific wavelengths of electromagnetic energy while allowing remaining wavelengths of the incident energy to pass.

Abstract: An optical film (210) includes a microstructured surface (211) comprising a plurality of prismatic structures (230), the microstructured surface (211) defining a reference plane (241-242) and a thickness direction (243) perpendicular to the reference plane; wherein the plurality of prismatic structures includes a plurality of facets (231), each facet having a facet normal direction forming a polar angle with respect to the thickness direction and an azimuthal angle along the reference plane, and wherein the microstructured surface has a surface azimuthal distribution of the plurality of facets that is substantially uniform, and wherein the microstructured surface has a surface polar distribution of the plurality of facets that has an off-axis peak polar distribution.

Abstract: Lighting devices having optical waveguides for controlled light distribution are provided. A lighting device includes a housing, a light emitter disposed in the housing, and a waveguide at least partially disposed in an opening of the housing. The waveguide includes a light input surface defining coupling features, wherein the light emitter is disposed adjacent the light input surface and emits light into the coupling features. The waveguide further includes a light transmission portion disposed between the light input surface and a light extraction portion, wherein light from the light emitter received at the light input surface propagates through the light transmission portion toward the light extraction portion. The waveguide further includes the light extraction portion, which comprises at least one light redirection feature and at least one light extraction feature that cooperate to generate a controlled light pattern exiting the lighting device.

Abstract: A lightguide component for illumination devices having first and second exit surfaces at opposite sides, the lightguide component including: a light-receiving portion to receive light emitted from a light source; a lightguide layer having a first principal face at the first exit surface side and a second principal face at the second exit surface side; and a light distribution controlling structure having a plurality of internal spaces. Each of the plurality of internal spaces includes a first slope to direct a portion of light propagating in the lightguide layer toward the first exit surface via total internal reflection, and a second slope at an opposite side from the first slope, and the lightguide component is configured to emit first light having a first intensity distribution through the first exit surface and to emit second light having a second intensity distribution through the second exit surface.

Abstract: A reflective display body configured such that the up-down direction of display content on a display surface can be changed. The reflective display body includes a light diffusion control layer, a display device, and a reflective layer. The light diffusion control layer has a diffusion angle width of 5° or more and 80° or less in which a haze value (%) is 90% or more as measured when one surface of the light diffusion control layer is irradiated with light rays at an incident angle of ?70° to 70° with respect to the normal direction of the one surface being 0°. The light diffusion control layer has an acute angle of 7° or more and 83° or less.

Abstract: Provided are an optical element, including a plurality of optically anisotropic layers, each of which has an in-plane alignment pattern in which orientations of optical axes derived from a liquid crystal compound change continuously and rotationally along at least one in-plane direction, in a thickness direction, in which the optically anisotropic layers each have regions where lengths over which the orientations of the optical axes rotate by 180° in the one direction are different from each other, and at least one of the plurality of optically anisotropic layers is an inclined optically anisotropic layer having a region where a plurality of pairs of bright lines and dark lines in a cross-sectional image are present and the pairs of the bright lines and the dark lines are inclined at inclination angles which are different from each other with respect to a normal line of an interface of the optically anisotropic layer.

Abstract: According to one or more embodiments described herein, a coated article may comprise: a transparent substrate having a major surface, the major surface comprising a textured or rough surface inducing light scattering; and an optical coating disposed on the major surface of the transparent substrate and forming an air-side surface, the optical coating comprising one or more layers of material, the optical coating having a physical thickness of greater than 300 nm, wherein the coated article exhibits a maximum hardness of about 10 GPa or greater as measured on the air-side surface by a Berkovich Indenter Hardness Test along an indentation depth of about 50 nm or greater.

Abstract: An LED filament comprising a plurality of LED filament units, each of the plurality of LED filament units includes a LED chip with an upper surface and a lower surface opposite to the upper surface of the LED chip, and a light conversion layer comprising a top layer and a base layer, and the base layer comprises an upper surface and a lower surface opposite to the upper surface of the base layer, where the top layer with an upper surface and a lower surface opposite to the upper surface of the top layer is disposed on at least two sides of each of the LED chips, the lower surface of each of the LED chips is close to the upper surface of the base layer, and the upper surface of the top layer is away from each of the LED chips.

Abstract: An electronic device includes a display panel and a viewing angle control unit disposed opposite to the display panel. The viewing angle control unit includes a first substrate; a second substrate disposed opposite to the first substrate; a plurality of protrusions disposed between the first substrate and the second substrate; and a plurality of shielding units disposed between the first substrate and the second substrate and disposed corresponding to the plurality of protrusions. One of the shielding units forms a first projection on the first substrate, one of the protrusions forms a second projection on the first substrate, and the second projection falls within the first projection.

Abstract: An electronic device may be provided with a display. The display may be overlapped by an antiglare film. The antiglare film may have a rough surface to diffuse incident light, thereby reducing glare. Additionally, the antiglare film may have a smooth portion that forms a transparent window and allows light to pass through undiffused. The electronic device may include a light-based component, such as a camera, that receives undiffused light through the transparent window. By overlapping the light-based component with the transparent window, the light-based component may receive the light in an unimpeded manner, thereby making more accurate measurements of the light. The display may have one or more display layers, such as opaque masking layers or polarizers, with openings that are aligned with the transparent window. The light-based component may receive the light through these openings so that the light is not absorbed or polarized before reaching the component.

Abstract: Examples are disclosed that relate to backlight modules, displays including a backlight module, and methods for assembling a backlight module. In one example, a backlight module for a display comprises light sources affixed to a printed circuit and a light guide plate. An adhesive affixes the printed circuit to the light guide plate. The light guide plate comprises a body and a plurality of projections extending from the body, with the plurality of projections retaining two or more of the light sources between the projections and the body of the light guide plate.

Abstract: A diffusion sheet structure includes a transparent substrate and a diffusion film. The transparent substrate includes a first upper surface and a first lower surface. The diffusion film is disposed on the transparent substrate and includes a plurality of nano diffusion particles, and has a second upper surface and a second lower surface. The second lower surface is connected to the first upper surface. Janus material in a diffusion sheet is used in the present disclosure to replace diffusion particles of prior art, which not only retains original function of diffusing light, but also has excellent thermal conductivity, thereby improving thermal uniformity, making the liquid crystal display panel be heated uniformly, and reducing influence of temperature on liquid crystal material during lighting, thereby improving the problem of local area whitening.

Abstract: A light emitting element array is provided and includes substrate; light emitting elements arrayed to substrate; first anisotropic diffusion layer facing substrate with light emitting elements interposed between first anisotropic diffusion layer and substrate; and second anisotropic diffusion layer, wherein first anisotropic diffusion layer and second anisotropic diffusion layer are layered, first anisotropic diffusion layer and second anisotropic diffusion layer each include a region in an in-plane direction including a high refractive index region and a low refractive index region in a mixed manner, and absolute value of first angle formed by boundary between high refractive index region and low refractive index region of first anisotropic diffusion layer and direction perpendicular to substrate is different from absolute value of second angle formed by boundary between high refractive index region and low refractive index region of second anisotropic diffusion layer and direction perpendicular to substrate

Abstract: An optical adhesive including a viscoelastic or elastomeric adhesive layer and a cured polymer layer immediately adjacent the viscoelastic or elastomeric adhesive layer is described. The viscoelastic or elastomeric adhesive layer a refractive index less than 1.570 and the cured polymer layer has a refractive index of at least 1.570. An interface between the viscoelastic or elastomeric adhesive layer and the cured polymer layer is structured. The cured polymer layer has a storage modulus of at least 2000 MPa at 20° C. and a glass transition temperature of no more than 65° C.

Abstract: An optical system including a lighting component and a switchable diffuser in optical communication with the lighting component. The optical system may further include a low absorbing optical component. At least one outer surface of the switchable diffuser and/or the low absorbing optical component includes light redirecting structures. When the switchable diffuser is in a first state and the optical system produces a light output, the light redirecting structures are configured to increase the full width at half-maximum (FWHM) of the light output of the optical system in at least one direction by at least 5 degrees relative to that of an otherwise equivalent optical system that does not include the light redirecting structures.

Abstract: An electronic device may display image content via a tile-based display by controlling light emission from display pixels of the tile-based display. Based on image data associated with the image content, a processing circuitry of the tile-based display may receive a potential tile boundary. The processing circuitry may resample the image data based on geometry of the tile boundary and positions of the display pixels on the tile-based panel. After resampling the image data, the processing circuitry may adjust gain of the tile boundary display pixels according to a gain mask to compensate for the tile boundary.

Abstract: Lighting devices having optical waveguides for controlled light distribution are provided. A lighting device includes a housing, a light emitter disposed in the housing, and a waveguide at least partially disposed in an opening of the housing. The waveguide includes a light input surface defining coupling features, wherein the light emitter is disposed adjacent the light input surface and emits light into the coupling features. The waveguide further includes a light transmission portion disposed between the light input surface and a light extraction portion, wherein light from the light emitter received at the light input surface propagates through the light transmission portion toward the light extraction portion. The waveguide further includes the light extraction portion, which comprises at least one light redirection feature and at least one light extraction feature that cooperate to generate a controlled light pattern exiting the lighting device.

Abstract: A laminate used under an environment irradiated with external light includes a light diffusion control film having an internal structure in the film. The internal structure includes a plurality of regions having a relatively high refractive index in a region having a relatively low refractive index. The laminate further includes an ultraviolet absorbing layer located further on the external light incident side than the light diffusion control film. The light diffusion control film contains a hindered amine-based compound.

Abstract: The present invention relates to a nano-protrusion forming method and a base material having a nano-protrusion surface formed by the method. The method includes forming an anti-reflective layer including nano-protrusions having a width of several nm to several tens of nm, and/or an anti-glare layer including protrusions having a width of several tens of nm to several ?m, by a wet etching process using an acid solution without using a nano-mask.

Abstract: Provided is a black light-shielding member, which has an excellent effect of anti-reflection that based on low glossiness and has a high blackness. A black light-shielding member including a substrate film, a resin-made light-shielding layer having a concave-convex shape formed on at least one surface of the substrate film, and a blackened layer formed on the resin-made light-shielding layer is produced. By adjusting an arithmetic mean surface roughness Ra of the surface on which the light-shielding layer and the blackened layer are formed to be 0.25 ?m or more, and the maximum thickness of the blackened layer is less than the said Ra, a blackness with an L value of 12 or less is achieved.

Abstract: An image processing system is disclosed, comprising: an M-lens camera, a compensation device and a correspondence generator. The M-lens camera generates M lens images. The compensation device generates a projection image according to a first vertex list and the M lens images. The correspondence generator is configured to conduct calibration for vertices to define vertex mappings, horizontally and vertically scan each lens image to determine texture coordinates of its image center, determine texture coordinates of control points according to the vertex mappings, and P1 control points in each overlap region in the projection image; and, determine two adjacent control points and a coefficient blending weight for each vertex in each lens image according to the texture coordinates of the control points and the image center in each lens image to generate the first vertex list, where M>=2.

Abstract: A privacy display comprises a polarised output spatial light modulator, reflective polariser, plural polar control retarders and a polariser. A birefringent surface relief diffuser structure is arranged to transmit light from the display with high transparency and provide diffuse reflection of ambient light to head-on display users. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss and with low diffusion, whereas off-axis light has reduced luminance and increased diffusion. Further, overall display reflectivity is reduced for on-axis reflections of ambient light, while reflectivity is increased for off-axis light. The visibility of the display to off-axis snoopers is reduced by means of luminance reduction, increased frontal reflectivity and diffusion of ambient light. In a public mode of operation, the liquid crystal retardance is adjusted so that off-axis luminance and reflectivity are unmodified.

Abstract: A light diffusion control member includes a first light diffusion control layer and a second light diffusion control layer. The first light diffusion control layer and the second light diffusion control layer each has a regular internal structure that includes a plurality of regions having a relatively high refractive index in a region having a relatively low refractive index. The first light diffusion control layer and the second light diffusion control layer are laminated so that an angle between two respective vectors determined based on the regular internal structure in the first light diffusion control layer and the second light diffusion control layer is more than 0° and 90° or less.

Abstract: The present invention provides an optical film structure, which comprises a base layer, a plurality of optical layers, and a prism layer. A first optical structure is disposed below the base layer such that the first optical structure can concentrate and alter an incident light source. By using the structure of the plurality of optical layers, the ineffective polarized light of the light source can be converted into effective polarized light. Furthermore, the first optical structure adjusts a focal point of the incident light source and thus increasing the luminous flux and brightness of the light source.

Abstract: The present invention provides a display panel and a display device. The display panel includes an array substrate, a color film substrate disposed on the array substrate, and a photochromic glass layer disposed on the color film substrate. A color change region is formed when an ultraviolet laser irradiates the photochromic glass layer, and the color change region filters passing lights. The display panel further includes a plurality of scattered particles distributed on the photochromic glass layer.

Abstract: The present invention provides a new member having a low refractive index as a substitute for an air layer, for example. The laminated film roll of the present invention includes a long laminated film roll including: an ultra-low refractive index layer having a refractive index of 1.20 or less; and a resin film, wherein the ultra-low refractive index layer is stacked on the resin film. The method of forming the long laminated film roll of the present invention includes steps of: preparing a liquid containing microporous particles; coating a resin film with the liquid; and drying the liquid applied on the resin film, for example.

Abstract: A platform for design of a lighting installation generally includes an automated search engine for retrieving and storing a plurality of lighting objects in a lighting object library and a lighting design environment providing a visual representation of a lighting space containing lighting space objects and lighting objects. The visual representation is based on properties of the lighting space objects and lighting objects obtained from the lighting object library. A plurality of aesthetic filters is configured to permit a designer in a design environment to adjust parameters of the plurality of lighting objects handled in the design environment to provide a desired collective lighting effect using the plurality of lighting objects.

Abstract: The optical assembly comprises: a first optical film having a first surface; an adhesive disposed on the first surface of the first optical film, wherein the adhesive comprises a photo-curable portion and a thermally-curable portion mixed with the photo-curable portion, wherein the weight ratio of the thermally-curable portion of the adhesive to the adhesive is less than 5%; and a second optical film comprising a photo-curable material, wherein the adhesive is bonded to the second optical film through the bonding between the photo-curable portion of the adhesive and the photo-curable material of the second optical film.

Abstract: An optical film including a first film substrate and a coating layer formed on the first film substrate. The coating layer of this optical film contains a binder resin and fine particles with an average size of 0.5 ?m or more and 10.0 ?m or less and a standard deviation in size that is less than ½ of the average size.

Abstract: A beam homogenizer for transforming a beam of laser-radiation into a flat-top intensity distribution having brighter or darker edges comprises a first lens array, a second lens array, and a positive lens. The first lens array includes a plurality of lens elements that are separated by gaps having no optical power. Brighter or darker edges are produced by selecting a distance between the first and second lens arrays that is less than or greater than the focal length of lens elements in the second lens array.

Abstract: An optical lens module includes a lens assembly and a plastic barrel. The lens assembly includes a plurality of lens elements and is disposed in the plastic barrel. The plastic barrel includes an object-end portion, an image-end portion, an outer tube portion, an inner tube portion and at least one reflection reduction area. The image-end portion includes an image-end opening. The inner tube portion includes a plurality of parallel inner surfaces and a plurality of inclined inner surfaces, wherein the parallel inner surfaces are parallel to the central axis, and each of the inclined inner surfaces has an angle with the central axis. The reflection reduction area is disposed on one of the inclined inner surfaces closest to the image-end opening, wherein the reflection reduction area and the plastic barrel are integrally formed by an injection molding method.

Abstract: An optical device, such as a diffuser, can include a substrate; and a diffuser surface, in which the diffuser surface has an index of refraction greater than about 1.8. A method of making and using the optical device is also disclosed.

Abstract: An embodiment of a method of manufacturing a cover lens for an electronic display includes etching a first surface geometry on a first surface of the cover lens. In the embodiment, the method includes determining a plurality of angles of refraction at the first surface from light generated from the electronic display based on the first surface geometry. In the embodiment, the method includes determining a second surface geometry for a second surface of the cover lens based on the plurality of angles of refraction at the first surface. In the embodiment, the method includes etching the second surface geometry on the second surface of the cover lens.

Abstract: A display device and an optical film are provided. The optical film is disposed on the display surface of the display device, and includes an anti-glare layer and an anti-reflection layer. The anti-glare layer has a first light-incident surface and a first light-exit surface. The anti-reflection layer is disposed on the first light-exit surface. The anti-reflection layer has a second light-incident surface and a second light-exit surface facing away from each other. The second light-incident surface faces the first light-exit surface of the anti-glare layer. The specular reflectance of the optical film is smaller than or equal to 0.14% for a light ray incident to the second light-exit surface at an incident angle ranging from 10 degrees to 30 degrees.

Abstract: An anti-glare film is attached on a surface of a display, and includes an anti-glare layer. The anti-glare layer is set to have a sparkle value of 10 or less, which is defined based on a value of a standard deviation of luminance distribution of the display under a state in which the anti-glare film is attached on the surface of the display, a value of specular gloss of 40% or less, which is measured with 60-degree specular gloss, and a value of transmission image clarity of 40% or less, which has an optical comb of 0.5 mm. Consequently, satisfactory anti-glare property can be provided while appropriately suppressing sparkle on the display.

Abstract: A polarizing plate and an optical display including the same are provided. A polarizing plate includes a display region and a non-display region surrounding the display region and includes: a polarizer; and a bonding layer, a first polarizer protective film, and a functional coating layer sequentially stacked on a surface of the polarizer. The bonding layer includes a printed layer therein to correspond to the non-display region. The polarizing plate has a haze of about 0.1% to about 5% as measured on the functional coating layer and a reflectance difference of about 2.4% or less between the display region and the non-display region, or the polarizing plate has a haze of about 20% to about 40% as measured on the functional coating layer and a reflectance difference of about 1.5% or less between the display region and the non-display region.

Abstract: An optical element includes a first resin portion, a second resin portion provided in contact with the first resin portion, an adhesion portion, a first base material, and a second base material, the first resin portion, the second resin portion, and the adhesion portion being provided between the first base material and the second base material. The adhesion portion is in contact with the second resin portion and one of the first base material and the second base material. When an elastic modulus of the first resin portion is denoted by E1, an elastic modulus of the second resin portion is denoted by E2, and an elastic modulus of the adhesion portion is denoted by E3, the optical element satisfies a relationship of E3<E2<0.9×E1.

Abstract: According to some embodiments, a transparent screen includes a first transparent substrate having a first transparent substrate index of refraction and including a surface relief pattern, a partially reflective coating formed on the surface relief pattern, and a second transparent substrate bonded over the partially reflective coating with an optical adhesive having the first transparent substrate index of refraction.

Abstract: A structure for extracting light, which improves light extraction efficiency by enhancing a scattering effect and improves power efficiency and thus increases the lifetime of an organic electroluminescent lighting device, is provided, and an organic electroluminescent lighting device including the structure for extracting light is also provided.

Abstract: According to an aspect, there is provided a display unit for generating a display output, comprising a first light source; a first back polarizer arranged to polarize light from the first light source in a first polarization direction; a second light source; a second back polarizer arranged to polarize light from the second light source in a second polarization direction that is orthogonal to the first polarization direction; a first substrate; a second substrate; a liquid crystal layer positioned between the first substrate and the second substrate, wherein the first substrate, second substrate and liquid crystal layer are arranged to receive light from the first light source that has been polarized by the first back polarizer and receive light from the second light source that has been polarized by the second back polarizer; and a front polarizer arranged to polarize light, the front polarizer being for polarizing light that has passed through the liquid crystal layer; wherein operating the first light sour

Abstract: According to the present invention, a light guiding laminate including a light guide plate with good visibility and an anisotropic optical film, and a planar light source device including the light guiding laminate and a light source are provided.

Abstract: A planar illumination device includes a light source substrate, a lens, a diffuser, and a spacer. The light source substrate includes a plurality of light-emitting devices two-dimensionally arrayed thereon. The lens receives light emitted from the light source substrate. The diffuser receives light emitted from the lens. The spacer is integrated with the diffuser and disposed between the lens and the diffuser.

Abstract: An exemplary embodiment provides a display device including: a display panel; and an anti-reflective layer configured to overlap the display panel, wherein the anti-reflective layer includes: a nano-pattern layer configured to include a plurality of nanostructures; and a low-refraction layer configured to cover the nanostructures, wherein the nanostructures are irregularly disposed.

Abstract: A detection method for an image acquisition device, a detection device for an image acquisition device, an electronic device and a computer readable storage medium are disclosed. The image acquisition device includes a light source and a diffuser, the diffuser is configured to scatter light emitted by the light source and the light emitted by the light source is irradiated on at least partial area of a scene, the image acquisition device includes: acquiring an image of the scene; determining an effective area of the image; and determining whether or not the diffuser is in an abnormal working state according to information of the effective area.

Abstract: Provided is a light unit including a plurality of LED light sources formed on a PCB, a resin layer stacked on the PCB to diffuse and guide emitted light forwards, and a diffusion plate having an optical pattern printed thereon to shield light emitted from the LED light sources. The optical pattern is composed of a diffusion pattern implemented as at least one layer, or a combination of the diffusion pattern layer and a light shielding pattern. The light unit forms an optical pattern for shielding or diffusing light on a surface of a light diffusion plate of the back-light unit, and combines a diffusion pattern and a metal pattern to attain uniformity of light and realize a yellow-light shielding effect, thus leading to a reliable light quality.

Abstract: Provided is a light unit including a plurality of LED light sources formed on a PCB, a resin layer stacked on the PCB to diffuse and guide emitted light forwards, and a diffusion plate having an optical pattern printed thereon to shield light emitted from the LED light sources. The optical pattern is composed of a diffusion pattern implemented as at least one layer, or a combination of the diffusion pattern layer and a light shielding pattern. The light unit forms an optical pattern for shielding or diffusing light on a surface of a light diffusion plate of the back-light unit, and combines a diffusion pattern and a metal pattern to attain uniformity of light and realize a yellow-light shielding effect, thus leading to a reliable light quality.