Abstract: A modular system of LED lighting provides for the use of LED lighting modules that are connectable using a interconnect module that provides structural rigidity. The LED lighting modules provide a sealed connection between adjoining LED modules, allowing their use under environmental conditions that may involve transient exposure to liquids such as water. Variants of the module allow using interconnect modules that allow flexible connections where rigidity is of less concern. Mounting features integrated into the interconnect modules allow mounting the interconnected lighting units to an installation site as desired.

Abstract: A message board lighting fixture has semiconductor based lighting elements for illumination and an integrated electronic message board display for displaying content to occupants of a transit vehicle or other area. The lighting fixture may include a concave fixture frame having a reflective interior, with lighting elements positioned along the length of the frame to provide area illumination. The electronic display may be mounted on a projecting frame substantially centrally within the cavity of the concave fixture frame, and may be augmented with additional semiconductor based lighting elements for backlighting. A detachable lens cover may have a diffusive portion and a separate transparent region over the electronic display area.

Abstract: A light source device and a light source system using the same are provided. The light source device includes a lens and a light source disposed under the lens. The lens has a light-emitting top surface and a bottom surface having a hole that is surrounded by an inner wall surface and an inner top surface. The inner top surface and a projection area of thereof onto the light-emitting top surface are flat surfaces. The light source has an illumination area, wherein an opening of the hole covers a projection area of the illumination area onto the bottom surface. The light source system includes a plurality of the light source device disposed in a honeycomb arrangement, wherein the light source devices are spaced apart from each other.

Abstract: In accordance with a first aspect of the present inventive subject matter, a lighting device includes light-emitting elements arranged in lines that are extended in parallel with one another, the light-emitting elements being divided into groups each including the same number of light-emitting elements, a first connecting electrode is disposed adjacent to one end portion of the lines extended, a second connecting electrode is disposed adjacent to another end portion of the lines extended, and the light-emitting elements within each group are electrically connected in series with one another by metallic wires and electrically connected in series to the first connecting electrode and to the second connecting electrode. The groups each include the same number of light-emitting elements that are electrically connected in parallel between the first connecting electrode and the second connecting electrode.

Abstract: Multiple-tier omnidirectional solid-state emission source capable of dispersing light in flexible distributions or custom-intensity distributions which throw more light forward, to the side alternatively, or in all directions. This optical light control requires multiple-surface manipulation of the directions of the light energy bundles emerging from solid-state light sources. Producing uniform light up to 325 degrees in the vertical direction through the combined implementation of multi-stage light guiding for remote source elongation and multiple-tiers of TIR, refraction, and scatter for remote source emission and control. Combining the efficient light production of an LED chip with that of a directly coupled optic results in high efficiency custom distribution to direct light where required.

Abstract: A high-efficiency LED lamp is disclosed. Embodiments of the present invention provide a high-efficiency, high output solid-state lamp. The lamp includes an LED assembly, and an optical element or diffuser disposed to receive light from the LED assembly. The optical element includes a primary exit surface for the light, wherein the primary exit surface is at least about 1.5 inches from the LED assembly. In example embodiments, the optical element is roughly cylindrical in shape. An LED lamp according to some embodiments of the invention has an efficiency of at least 150 lumens per watt. In some embodiments, the lamp has a light output of at least 1200 lumens. In some embodiments, the LED lamp produces light with a color rendering index (CRI) of at least 90 and a correlated color temperature of from 2800 to 3000 K.

Abstract: A circular LED illumination lens for short throw lighting, for example, as part of a set of such devices installed on mullions in reach-in refrigerator cabinets, to uniformly light access across the rectangular door and shelves. The len has an upper surface with a cavity for the LED, an upper surface the shape of a toroid, generated by an elliptical arc, that serves to magnify the light rays from the LED in an outboard direction, and the minor axis tilted about 17 degrees relatives the center axis of the LED which serves to direct the rays at the center of the shelves. The upper surface also preferably includes a spherical dimple to direct light away from the center axis.

Abstract: The invention relates to alighting apparatus comprising a light emission unit (2) for emitting light (3) from an emission surface (4) in a main emission direction (6), and an outcoupling unit (7) for coupling the light out of the light emission unit. The outcoupling unit comprises a first surface (8) having a first central region (9) optically coupled to the emission surface and a first peripheral region (10) enclosing the first central region, and a second surface (11) opposite to the first surface. The peripheral regions can be structured, wherein the ratio of a) the area of the emission surface to b) the area of the first surface or the second surface is smaller than 0.5. This configuration can significantly decrease the likelihood of reabsorption of light by the emission surface, thereby increasing the efficiency of extracting light out of the lighting apparatus.

Abstract: A lens adjusts light emitted from a light source that emits the light in upward directions whereby light intensity of the adjusted light at a lateral side of the light source is increased. The lens includes a bottom surface and a top surface extending from an edge of the bottom surface. A first cavity recesses upwardly from the bottom surface for receiving a light source therein. An inner surface of the first cavity acts as a light inputting surface. A first dispersing portion protrudes downwardly from a top end of the light inputting surface. The light inputting surface collects light from the light source, the first dispersing portion disperses part of light from the light inputting surface and transmits the light to lateral sides of the light inputting surface and lateral sides of the top surface to illuminate.

Abstract: The present application provides light emitting diode (LED) lighting including a white LED and a red LED. Chromaticity of the white LED has a color temperature of between about 2800 K to about 3700 K within a range according to ANSI C78. 377-2008 standard, and a range of the color temperature corresponds to a higher range than a chromaticity locus defined by blackbody radiation.

Abstract: According to one embodiment, an illumination device includes a first light-transmissive member, a first chassis, and a first semiconductor light emitting unit. The first light-transmissive member has first and second member ends. The first chassis includes a first base portion, first and second side portions. The first base portion is separated from the first light-transmissive member and has first and second base ends. The first side portion extends from the first base end toward the first member end and has first and second end portions. The second side portion extends from the second base end toward the second member end and has third and fourth end portions. A distance between the first and third end portions is shorter than a distance between the second and fourth end portions. The first semiconductor light emitting unit is provided between the first and second side portions.

Abstract: To provide a back light unit that reduces an uneven brightness and has a spatially uniform brightness distribution. According to an aspect of the present invention, the back light unit comprises an LED and a light guide plate for guiding light from the LED to a liquid crystal panel side, wherein a recess is provided on the back surface side of the light guide plate, wherein a plurality of LEDs are housed in the recess, and wherein a light amount limiting member is provided at a position facing the recess on s light exit surface side of the light guide plate. The light amount limiting member is configured, for example, by applying an ink with a predetermined optical property to a transparent sheet.

Abstract: A light fixture for use in low voltage outdoor lighting systems includes a lens assembly with a cylindrical diffuser lens disposed on top of a lens support, and a reflector hood with a crown portion and a flared portion. The lens and reflector hood are attached by means of a resilient ring with an annular channel that fits over the upper edge of the lens. When the lens and ring are pushed into crown portion of the hood, the ring is compressed to create an interference fit that holds the lens within the crown portion. A second resilient ring may be placed over the lower edge of the lens to produce a similar interference fit with the upper portion of the lens support. In one embodiment, a molded plastic hood liner is attached to the inner surface of the hood to provide a reflective surface.

Abstract: A surface light source device includes an organic electroluminescent element including a luminescent layer and a light-emitting surface structure layer disposed on one of the surfaces of the organic electroluminescent element. In the surface light source device, the light-emitting surface structure layer includes a concave-convex structure provided on a surface thereof on the side toward a device light-emitting surface, and the concave-convex structure includes a plurality of concave portions having oblique surfaces and flat portions disposed around the concave portions. The flat portions and/or the concave portions have a size difference in one or more of their width, height, depth, and spacing, the size difference being larger than the difference that causes interference of one or both of emitted light and reflected light.

Abstract: A light emitting device that can reduce the illuminance unevenness on an illuminated surface. First light flux controlling member 103 controls the distribution of light emitted from light emitting element 102. Second light flux controlling member 105 has second incidence surface 201 onto which the light emitted from first light flux controlling member 103 is incident and second emission surface 202 that is located on a side opposite to second incidence surface 201 and emits the light incident from second incidence surface 201. Also, at least one surface of second incidence surface 201 and second emission surface 202 refracts the light having an optical path on a virtual cross-section including optical axis P1 of light emitting element 102 and being incident onto second incidence surface 201 or second emission surface 202 more to the optical axis P1 side than when being incident onto a plane perpendicular to optical axis P1.

Abstract: Disclosed is a thin LED lens including a lens body being an inverted frusto-conical shaped structure, a light exit surface formed on a non-frustum end of the lens body, and an accommodating chamber formed at a frustum end of the lens body, characterized in that the accommodating chamber has a primary accommodating chamber and at least one secondary accommodating chamber disposed around the primary accommodating chamber, such that the primary accommodating chamber and the secondary accommodating chamber are arranged in a concentric and radial shape, and the secondary accommodating chamber is in form of a circular groove. The thin LED lens can be made thinner to achieve the effects of facilitating the manufacture, reducing the material, and providing a better light distribution.

Abstract: An apparatus including: an illumination source; and a climate controlled enclosure having at least one light diffusion element situated within the enclosure, the at least one light diffusion element being in photonic communication with the illumination source, and the illumination source being remote to the enclosure. The disclosure also provides a method of using the apparatus to illuminate the interior of the apparatus and optionally the contents of the apparatus.

Abstract: A display apparatus for an electric hob may have a colored, such as reddish-brown, hob plate, which may be composed of glass ceramic and have an inhomogeneous transmission profile for light with high transmission in the region of wavelengths of greater than 700 nm and with low transmission in the region below 700 nm. The display apparatus may have one light source with a defined output spectrum. The color locus of the light source may be shifted to the left starting from white and have a blue tinge. This configuration may provide a display that is visible or that correspondingly lights up as a substantially white illuminated display through the colored cover.

Abstract: A luminaire includes an LED based illumination device with a light emitting area and an optical element that is configured to produce a hybrid emission pattern with a spot beam emitted within a predetermined far field angle and a background level spherical emission pattern. The optical element, for example, may be configured with an input port and an output port, and a perimeter that increases in size from the input port to a maximum perimeter and decreases from the maximum perimeter to the output port. The optical element receives an amount of light from the LED based illumination device at the input port, emits a first portion of the light from a curved, semitransparent sidewall, and emits a second portion of the light at the output port, wherein the emission area of the output port is less than a maximum perimeter of the optical element.

Abstract: An LED light bulb, mainly comprising: an LED module, provided with a first connection portion; a circuit driving module, provided with a second connection portion, said first connection portion is connected to said second connection portion; and a lamp hood covered over said LED module. As such, said LED module or said circuit driving module can be replaced readily when they are found broken down, without the need to discard entire set of LED light bulb, hereby eliminating unnecessary waste, in achieving both cost effectiveness and environment protection.

Abstract: A lens is provided in an asymmetric shape including at least two curved surfaces with different light distribution angles. Therefore, uniformity ratio of illuminance and coefficient of utilization (CU) may be increased while reducing dazzle. When a lighting apparatus including the lens is used as a street light, light directly incident to a driver is minimized, thereby reducing dazzle to the driver. During a night drive, brightness at a far forward position of the driver may be increased. In addition, light emitted toward a street may be increased while reducing light emitted toward a sidewalk. As a result, uniformity ratio of illuminance and coefficient of utilization (CU) may be increased. Also, light pollution may be reduced.

Abstract: A light guiding structure includes a light transmissive body and microstructures; the light transmissive body includes an upper conical groove and a lower accommodating groove, and the upper conical groove has a curved surface with a continually varied slope; the microstructures are disposed on the light transmissive body. A lighting device includes a circuit board, a light source and the aforesaid light guiding structure; the light source and the light guiding structure are disposed on the circuit board, and the light source is accommodated within the lower accommodating groove.

Abstract: A hybrid lens for a solid state light source device is provided. The hybrid lens includes a first component and a second component. The first component has a first side and a second side oppositely disposed thereto. The first side is positioned facing a solid state light source. The second component is attached to the first side of the first component. The first component includes a flame retardant material, such as a glass or a filled polymer. The second component includes a non-flame retardant material, such as an unfilled polymer.

Abstract: A modular LED light unit for mounting to an object to illuminate distally located objects comprises a circuit board supporting a plurality of LED lights and a light permeable front cover. The circuit board includes a plurality of apertures with the LED lights being reverse mounted to the circuit board such that each LED light is located by and extends into a separate one of the apertures. The front cover includes an outer surface and an inner surface and at least one optical structure located on the outer surface or inner surface. At least one of the LED lights is axially aligned with the optical structure whereby light emitted from the aligned LED lights is directed into the optical structure.

Abstract: An LED package structure is disclosed, which comprises an LED chip and a frame for receiving the LED chip, and the frame comprises a bottom wall, a first sidewall and a light exiting wall. The LED chip is disposed on the bottom wall, the first sidewall is obliquely disposed in a light exiting direction of the LED chip, and light rays emitted from the LED chip are reflected by the first sidewall and then exit from the light exiting wall. An LCD device is further disclosed. According to the LCD device and the LED package structure thereof of the present disclosure, light rays emitted from the LED chip are reflected by the first sidewall and then exit from the light exiting wall. This can increase the light mixing distance for the LED chip and avoid occurrence of light emission blind areas, thus eliminating the hot spot phenomenon.

Abstract: A LED based lighting apparatus comprising a low cost stamped frame comprising structural elements, LED attach region at a predetermined tilt angle and heat sink region enabling a lamp with uniform lighting distribution is disclosed.

Abstract: The present invention therefore provides for the use of a light-diffusing polycarbonate sheet based on a composition comprising A) 99.9 to 80% by weight of polycarbonate and B) 0.1 to 20% by weight of diffusing pigment selected from at least one from the group of the silicone resins and the acrylate resins as a light cover, preferably in LED light applications.

Abstract: A method for making a light emitting diode is provided. In the method, a substrate having an epitaxial growth surface is provided. A first semiconductor layer, an active layer, and a second semiconductor layer are grown on the epitaxial growth surface in sequence. The first semiconductor layer, the active layer, and the second semiconductor layer constitute a source layer. A metallic plasma generating layer is then formed on a surface of the source layer away from the substrate. A first optical symmetric layer is then disposed on a surface of the metallic plasma generating layer. a second optical symmetric layer is then disposed on a surface of the first symmetric layer away from the substrate. A first electrode is applied to electrically connect the first semiconductor layer. A second electrode is applied to electrically connect the second semiconductor layer.

Abstract: An illumination apparatus includes a light source unit comprising at least one light source module comprising a plurality of light-emitting device chips and a lead frame on which the light-emitting device chips are mounted and which connects the mounted light-emitting device chips; a diffusion cover having an interior space in which the light source module is accommodated and diffusing light emitted from the light source module; and an installation portion formed adjacent to the diffusion cover to install the light source module.

Abstract: A light emitting diode includes a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a third optical symmetric layer, a metallic layer, a fourth optical symmetric layer, and a first optical symmetric layer, and a second optical symmetric layer stacked with other in the listed sequence. The light emitting diode further includes a first electrode electrically connected with the first semiconductor layer and a second electrode electrically connected with the second semiconductor layer. A refractive index of the third optical symmetric layer or the fourth optical symmetric layer is in a range from about 1.2 to about 1.5. A refractive index difference between the source layer and the first optical symmetric layer is less than or equal to 0.3. A refractive difference between the second optical symmetric layer and the substrate is less than or equal to 0.1.

Abstract: A miniature SMD-HPLED replaceable lamp (10) comprising a main body (1) which can be alternatively made of ceramic or metallic material, an electrical connector (20) housed in said main body (1) and a PCB (3a) embedding an HPLED lighting source. The connector (20) is suitably designed both for assuring an electrical continuity between PCB (3a) and an external power supply and locking it in a slot (2) formed on said main body (1).

Abstract: A light emitting diode includes a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a first optical symmetric layer, a metallic layer, and a second optical symmetric layer stacked on the substrate in that sequence. A first electrode is electrically connected to the first semiconductor layer, and a second electrode is electrically connected to the second semiconductor layer. A first effective refractive index n1 of the second optical symmetric layer, a second effective refractive index n2 of an integrated structure satisfy |n1?n2|?0.5, wherein the integrated structure includes the substrate, the first semiconductor layer, the active layer, the second semiconductor layer, and the first optical symmetric layer.

Abstract: This disclosure relates to LED based lighting systems, such as surface mounted lighting systems and lighting systems that can connected to an existing grid structure. These lighting systems can be utilized in many settings, for example, as primary lighting systems for a commercial building and for retrofit lighting improvement purposes. Devices according to the present disclosure provide lighting systems capable of mounting to an existing surface, such as a T-bar ceiling structure. These devices can further comprise modular elements which facilitate connections of multiple lighting body components, allowing for multiple lighting arrangements and providing a cost effective and easily configurable lighting design. In some embodiments, multiple lighting components can be attached together by movable joints, allowing further user control over light distribution from the lighting systems.

Abstract: Proposed is a lighting module 100 and an illumination device 200 comprising such a module. The lighting module comprises an array of LEDs 120 mounted on a substrate 110 and an optical structure 130 encompassing the LED array for approximating in operation the LED array as a single homogeneous light source. The optical structure comprises an optical element 140 arranged to provide a luminous intensity profile as a function of a deviation angle a which is substantially constant between ??max and ?max, wherein ?max is a maximum deviation angle provided by the optical element and substantially zero at angles outside that range. This is especially advantageous for optimizing the trade off between creating a single homogenous light source and maintaining the entendue of the light source. An additional advantage of the optical element 140 is that, except for fresnel reflections on both surfaces, it has no backscattering like a diffuser has, which results in a very low optical loss.

Abstract: An optical semiconductor lighting apparatus including a housing with a first end portion and a second end portion that is open, a light source module disposed in the housing, a fan disposed adjacent to the light source module in the housing, the fan rotating in a first direction to blow air toward the light source module, and a reflector disposed adjacent to the second end portion of the housing, the reflector enhancing an illumination scope. A moving path, in which at least a portion of the air drawn into the housing by the fan externally flows through the light source module, is formed in the housing.

Abstract: An optical arrangement and a solid-state lighting system comprise an optical element having at least one lens where the lens has a faceted surface defining a plurality of facets. An LED light source comprises a plurality of LED chips and is arranged relative to the faceted surface such that the plurality of facets are disposed asymmetrically relative to the plurality of chips such that mixing of light from the plurality of LED chips occurs via the surface.

Abstract: A method for making a light emitting diode is provided. In the method, a substrate having an epitaxial growth surface is provided. A buffer layer, a first semiconductor layer, an active layer, a second semiconductor layer are grown on the epitaxial growth surface in sequence. The first semiconductor layer, the active layer, and the second semiconductor layer constitute a source layer. A third optical symmetric layer, a metallic layer, a fourth optical symmetric layer, and a first optical symmetric layer are then disposed on a surface of the second semiconductor layer away from the substrate in the listed sequence. The substrate and the buffer layer are removed to expose the first semiconductor layer. A first electrode is applied on an exposed surface of the first semiconductor layer and a second electrode is applied to electrically connect with the second semiconductor layer.

Abstract: A semiconductor structure includes a first semiconductor layer, a active layer, a second semiconductor layer, a third optical symmetric layer, a metallic layer, a fourth optical symmetric layer, and a first optical symmetric layer stacked in sequence. The first semiconductor layer, the active layer, and the second semiconductor layer constitute a source layer. A refractive index of the third optical symmetric layer or the fourth optical symmetric layer is in a range from about 1.2 to about 1.5. A refractive index difference between the source layer and the first optical symmetric layer is less than or equal to 0.3.

Abstract: The present invention relates to luminaires and, in particular, to luminaires comprising light emitting diodes. In one embodiment, the present invention provides a luminaire comprising at least one light emitting diode, a reflector offset from the centerline of the luminaire and a collimator adapted to direct light from the least one light emitting diode along an axis offset from the vertical axis of the light emitting diode.

Abstract: A light emitting diode includes a substrate, a source layer, a metallic plasma generating layer, a first optical symmetric layer, a second optical symmetric layer, a first electrode, and a second electrode. The source layer includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked on a surface of the substrate in series. The first electrode is electrically connected with the first semiconductor layer. The second electrode is electrically connected with the second semiconductor layer. The metallic plasma generating layer is disposed on a surface of the source layer away from the substrate. The first optical symmetric layer is disposed on a surface of the metallic plasma generating layer away from the substrate. The second optical symmetric layer is disposed on a surface of the first optical symmetric layer away from the substrate.

Abstract: A light emitting diode includes a first semiconductor layer, an active layer, a second semiconductor layer, a third optical symmetric layer, a metallic layer, a fourth optical symmetric layer, and a first optical symmetric layer, a first electrode, and a second electrode. The first semiconductor layer includes a first surface and a second surface opposite to the first surface. The active layer, the second semiconductor layer, the third optical symmetric layer, the metallic layer, the fourth optical symmetric layer, and the first optical symmetric layer are stacked on the second surface in sequence. The first electrode covers and contacts the first surface. The second electrode is electrically connected with the second semiconductor layer. The first semiconductor layer, the active layer, and the second semiconductor layer constitute a source layer.

Abstract: An LED based lamp has an optically transmissive enclosure connected to a base. The base may include a heat sink. A substrate is positioned in the enclosure and supports a plurality of LEDs where the periphery of the substrate has alternating recessed portions and protruding portions that define a plurality of laterally extending projections. One LED is located on each of the projections to increase the amount of down light generated by the lamp.

Abstract: A light source unit of a light engine is disclosed, wherein the light source unit includes a plurality of LED sub light source units each comprising at least one LED and an optical device corresponding to the at least one LED, the optical device is configured to modify a beam from each LED to be an approximately collimated beam.

Abstract: A light source module including a substrate, a plurality of light emitting devices installed on the substrate, and a plurality of lenses installed on the substrate to cover the plurality of light emitting devices, respectively, and each of the plurality of lenses having a pair of open end portions facing one another, the plurality of lenses arranged such that an open end portion of one lens faces an opened end portion of an adjacent lens is provided.

Abstract: A light emitting device includes: a substrate; a semiconductor light emitting element provided on the substrate; a sealing member which covers the semiconductor light emitting element; and a lens having a plurality of convex parts and a concave part. The light emitting device emits light having a non-concentric luminance distribution made up of a plurality of bright regions and a plurality of dark regions, the non-concentric luminance distribution being observed on a plane which is parallel to the substrate. This makes it possible to provide (i) a display device which has a thin body and hardly causes unevenness in luminance and in chromaticity, and (ii) a light emitting device and (iii) a surface illuminant suitable, which are suitable for use in the display device.

Abstract: A lighting circuit substrate is arranged in a cap so that one surface of a lighting circuit substrate and a flat portion of a cap projection are arranged so as to face each other. Also, lighting circuit components are mounted on the one surface of the lighting circuit substrate, and the lighting circuit components are arranged within the cap projection. Arrangement is such that a clearance between the lighting circuit substrate and the flat portion of the cap projection becomes larger than the height of a component whose projecting dimension from the lighting circuit substrate is the largest from among the lighting circuit components.

Abstract: Solid state lighting devices include elongated heatsinks with multiple raised features each including a major surface non-parallel to a longitudinal direction of the heatsink. A device-scale heatsink including raised features may include at least a portion of a threaded rod or tube, with threads thereof forming the raised features. Raised features may also be formed by stamped and bent emitter support elements arranged to support solid state light emitters, with the emitter support elements inserted into recesses of an elongated heatsink body.

Abstract: An optical waveguide includes a body of optically transmissive material having a width substantially greater than an overall thickness thereof and including a first side, a second side opposite the first side, a central bore extending between the first and second sides and adapted to receive a light emitting diode, and extraction features on the second side. A light diverter extends into the central bore for diverting light into and generally along the width of the body of material. The extraction features direct light out of the first side and wherein at least one extraction feature has an extraction surface dimension transverse to the thickness that is between about 5% and about 75% the overall thickness of the body of material.

Abstract: A luminaire having a waveguide suspended beneath a mounting element, the waveguide has a first surface proximal to the mounting element, a second surface distal to the mounting element, and an edge between the first and the second surfaces. At least one cavity extends into the waveguide from the first surface to the second surface. A LED component is coupled to the waveguide so as to emit light into the cavity. LED support structures are also disclosed.

Abstract: A lens for controlling an illuminance distribution to realize high luminous flux efficiency by maintaining a required beam angle and uniformity on an illumination surface having a particular shape, such as a square shape, and a light-emitting diode (LED) package including the lens are provided. The lens includes an incidence surface onto which light emitted from a light-emitting device is incident, and an emission surface through which the light incident onto the incidence surface is emitted. An illuminance controller, which includes at least two optical devices, is disposed on the emission surface to control an illuminance distribution of the emission surface.