Abstract: A high intensity light projector for stage, architectural and similar applications includes a controllable image quality projection gate providing advanced visual effects. The projection gate, capable of selectively scattering or transmitting incident light, may be constructed of an array of scattering liquid crystal material in combination with infrared and ultraviolet reduction means which provide in the high intensity beam, a stable thermal environment by minimizing the absorption of light by the projection gate. Additional thermal efficiency is provided by supplemental cooling means. Color control is also provided in the form of dichroic filter wheels forming cooperating adjustable low, high and band width filters including saturation control. A color measuring feedback sensor is also provided. An intensity measuring feedback sensor controls a spatially-modulated, variable-density, reflectively-coated dimming wheel. A programmable gobo system has provisions for gobo selection, orientation, and rotation.

Abstract: A projector particularly for projecting light in infinite colors, comprising a pair of light sources arranged side by side and inserted in a single luminaire, a single dimmer element, a single color changer and a single diffuser element being arranged after the lamps, in order to obtain in output a light beam determined by the sum of the light beams emitted by the light sources arranged side by side.

Abstract: A discharge lamp and a headlight for a motor vehicle are proposed. A moving member is provided, which is movable between at least two positions, for switching over between different light distributions. It comprises at least one optically active element, preferably a lens, which generates an image of the gas discharge which is shifted away from the actual location thereof. A switch-over between two different light distributions is made possible by a movement of the moving member between the two positions in the headlight, such that the gas discharge seems to be shifted by the switch-over for a respective region of the reflector, whereby different light distributions are created. Preferably, the moving member is the outer bulb of the discharge lamp, on which two lenses are arranged and which is rotatable about the optical axis.

Abstract: A rotating lamp shade display system including a carousel having a main body portion having an upper surface and an underside for receiving a plurality of shades on upper surface, a main body portion rotating means is mounted to the underside of said main body portion whereby said main body portion rotates about said rotating means. A plurality of said shades are placed on the main body portion for display.

Abstract: Illumination angle adjuster (42) for condensing illumination light from a light generator (41) toward a workpiece (25) includes a simple-structured optical member of condenser lens (44). With the simple arrangement, illumination angle of the illumination light to the workpiece (25) can be easily changed by moving the condenser lens (44) along an optical axis of an optical system (37).

Abstract: A vehicle lamp unit is disclosed that utilizes a high intensity discharge bulb for high beam, low beam and fog/driving lamps. The lamp uses reflectors and shields to selectively block light emitted from the HID bulb and to direct the light into a desired pattern. A control device is utilized to move the shields into various desired light blocking positions. Lamps of various shapes can be fabricated using the shield system by using optics to direct light into diverse preferred patterns.

Abstract: An illuminated revolving lamp device having a rotating translucent member surrounding a source of light and bearing colored patterns thereon, and a second translucent member formed with grating portions of various transmissiveness, the second translucent member adjacent first translucent member such that when the display device is viewed from a fixed location, a changing display of colors and shapes is observed.

Abstract: A lighting fixture projects a light beam for spot lighting in theater stages, cinema and television studios and the like. The fixture includes a light source at one end of a housing having a light beam exit aperture at the opposite end thereof, the light source and aperture being arranged generally concentric with a longitudinal or optical axis of the lighting fixture. One or more beam-shaping blades, and preferably also other light beam influencing elements, such as one or more lenses, an iris, and/or a pattern or gobo, are arranged along the path of the light beam along the longitudinal axis through the housing from the light source to the aperture. The position of the beam-shaping blade or blades, and preferably of all the light beam influencing elements, is adjustable relative to the longitudinal axis. The fixture produces a well-defined light beam or light cone with a geometry, angle of conicity and focal point that may be altered manually or by remote control.

Abstract: A dual reflector lighting system having an adjusting assembly for independently adjusting an inner reflector and an outer reflector relative to a gaseous discharge lamp. The lighting system includes a housing having a ballast assembly mounted therein. An elongated tubular adjusting member has one end thereof connected to the bottom of the housing. A lamp socket for receiving a gaseous discharge lamp is mounted to the other end of the adjusting member. The lamp socket is electrically connected to the ballast assembly. The system includes both an outer reflector and an inner reflector mounted coaxially about the gaseous discharge lamp. The outer reflector is mounted to the tubular adjusting member for movement relative thereto to adjust the outer reflector relative to the gaseous discharge lamp. The inner reflector is connected to the adjusting member for adjusting the inner reflector relative to the gaseous discharge lamp.

Abstract: A protective arrangement for a source of electromagnetic energy, such as an output light, is provided with a light port for issuing the output light and a displaceable shutter having a first position that overlies the light port and thereby limits access to the output light. In a second position, the displaceable shutter permits ready access to the light port. The displaceable shutter is arranged to default to the first position, whereby protection of personnel from the output light is effected. This can be achieved by configuring the displaceable shutter to be affected by gravity, or in environments where the equipment is portable or its orientation in use can be varied, by a resilient biasing element, such as a spring. An indicator arrangement is provided to provide indication that light is being emitted from the light port.

Abstract: For a concertina lamp (1) with a minimum of one concertina arm (2) and a minimum of two lamps (6, 12) attached to concertina arm rods (5) lying behind each other, a lampshade (4) is provided for each lamp (6, 12), which is attached to the same concertina arm rod (5) as the respective lamp (6, 12) and all lampshades (4) are telescopically designed so that they overlap each other at least partially while the concertina arm (2) is retracted.

Abstract: A combination color filter having at least two dual-hue color-changing absorptive substrates. A desired hue and saturation is achieved by using light absorbing gels for a plurality of selected hues, preferably the three subtractive primary colors. The unique arrangement of transparent part, saturation parts and continuously graded saturation parts allow fast color bumping between any two primary colors without flash of white and presence of other intervening colors.

Abstract: A dual reflector lighting system having an adjusting assembly for independently adjusting an inner reflector and an outer reflector relative to a gaseous discharge lamp. The lighting system includes a housing having a ballast assembly mounted therein. An elongated tubular adjusting member has one end thereof connected to the bottom of the housing. A lamp socket for receiving a gaseous discharge lamp is mounted to the other end of the adjusting member. The lamp socket is electrically connected to the ballast assembly. The system includes both an outer reflector and an inner reflector mounted coaxially about the gaseous discharge lamp. The outer reflector is mounted to the tubular adjusting member for movement relative thereto to adjust the outer reflector relative to the gaseous discharge lamp. The inner reflector is connected to the adjusting member for adjusting the inner reflector relative to the gaseous discharge lamp.

Abstract: A diffusing dimmer includes an arm formed of non-transparent material and having a first end and a second end. The first end includes a mounting attachment. An extension portion of light diffusing material is connected to the second end and extends outwardly from the second end to a terminal edge formed in the light diffusing material. A pair of diffusing dimmer arms may be mounted in a light fixture movable toward each other in overlapping relationship to gradually diffuse and eventually block a light beam which projects lighting effects from the fixture. Also, rapid movement of the arms provides a strobing effect.

Abstract: A new and improved lighting display comprising a base having an upwardly facing top surface. The top surface is reflective and has a plurality of spaced apart apertures therein. A light is positioned in each of the apertures such that a light beam from each light shines upwardly away from the reflective top surface. A frame is supported on the base and extends over the apertures. Ornaments are hung from the frame over each of the apertures whereby the light beams may be dispersed by the ornaments during use. In specific embodiments of the invention, light displays for use in motor vehicles as supplemental stop lights and turn signal lights is provided. In other specific embodiments, an ornamental light display is provided for decorative purposes.

Abstract: A light beam projector device having a light source and a reflector arranged to direct the light originating from the light source in such a manner as to form a light beam, said reflector having a curved concave reflecting surface with a geometrical focus where the light source is positioned, at least a first tubular wall made of a material able to filter color from the light and arranged when set in an active position to laterally embrace the light source so as to be traversed by the light before it reaches the reflector, the tubular wall being arranged with its axis substantially coinciding with the axis of the reflector, actuator means for axially moving the tubular wall into an active position or to an inactive position below the reflector where it does not interfere with the radiation emitted by the light source and directed towards the reflector, and to intermediate positions in which only a part of the tubular wall is traversed by the light, and a second tubular wall or tubular wall segment positioned

Abstract: An illuminator for a high energy remote lighting system includes a light source for generating light energy and a selectively positionable light output modifying apparatus having a plurality of light output modifying elements, each element corresponding to a predetermined position of at least a portion of the apparatus. At least some of the light output modifying elements of the apparatus are configured to filter light energy to provide either dimmed or colored light. The illuminator can be implemented in a system having a plurality of area control panels, each control panel generating a control signal indicative of a corresponding light characteristic, the illuminators each being coupled to a corresponding one of the area control panels to receive the control signal and to output a particular type of light in response thereto.

Abstract: Architectural luminaries utilize a common optical engine having a lamp coupled to an ellipsoidal reflector, a field stop aperture, and image-projecting lenses A color wheel, gobo wheel, and mechanical dimmer may also be included. A microlens element converts a spotlight optical engine into a wash light optical system. A multiple lens array provides variable diffusion. The optical engine is combined with an X-Y scanning mirror beam direction system in a substantially recessed housing for mounting in the ceiling of a building. The optical engine is combined with a pan-and-tilt yoke for greater range of coverage with an exposed luminaire.

Abstract: Apparatus for modifying a beam of light, comprising at least one set of blades moveable across the beam, wherein each set of blades is arranged into a first subset of blades and a second subset of blades, and wherein the respective subsets of blades are axially spaced from each other. The apparatus is particularly suitable in apparatus comprising a light source and means for directing and/or focusing the light, and may be embodied (a) in a color changer for changing the color of light in a light beam, (b) in a diaphragm for varying the aperture, and (c) in dimmer apparatus for dimming light beam.

Abstract: A lighting fixture configured to image a high-intensity beam of light at a distant location with a variable beam spread and a variable image distance. The lighting fixture includes an illuminator mounted on a front projection system. The illuminator includes an elliptical reflector defining two focal points. A lamp is at one of the reflector's focal points, while an aperture of the front projection system is at the reflector's other focal point. The front projection system includes a tubular housing having shutter blades moveably positionable in the aperture to obstruct light passing through the second focal point. A rear lens receives and transmits light emitted by the illuminator, while a front lens is configured to receive light transmitted by the first lens and project it at the distant location. The lenses are contained within the housing.

Abstract: A lighting conduit system for collecting sunlight and distributing it inside a building structure to provide natural lighting to the inside of the building structure. The lighting conduit system includes a plurality of interconnected elongate tubular conduits adapted for mounting inside a building structure. Each of the conduits has a lumen in communication with the lumens of the other conduits to permit passage of light between the lumens of the conduits. The conduits include a plurality of fixture conduits each comprising spaced apart and generally concentric inner and outer sleeves each having upper and lower portions. The lower portions of the inner and outer sleeves each comprise a translucent material to permit passage of light in the lumen of the respective conduit through the lower portions of the inner and outer sleeves. The conduits also include a terminal conduit with an outer end adapted for extending outside of the building structure.

Abstract: A head lamp for a vehicle wherein an actuator is made to be able to be moved to a leveling actuation range corresponding to output from a vehicle body sensor and to a beam change position B out of a leveling actuation range when a beam changing switch is set to a drive beam position, and if the actuator is moved to the beam change position B at least a part covering a lower half of a discharge lamp of the hood is moved back to switch it from a passing beam state to a drive beam state. The actuator for leveling actuation indispensable to be provided for the head lamp for a vehicle having the discharge lamp as a light source, makes it possible also to switch between the passing beam state and drive beam state, thereby dissolving problems of large size and high cost of the head lamp.

Abstract: An array of disks faces a viewing direction is composed of disk's rotatable about an axis approximately perpendicular to the viewing direction between alternating orientations where bright and dark sides are respectively displayed in the viewing direction. There is provided a row of LED's located forwardly of the array and out of the normal viewing path located to illuminate the disks of said array. Masking means prevents direct illumination from said LED's being visible in the viewing direction.

Abstract: Overlapping lenses for use in a light fixture provided to project a beam of light in a first beam shape having a first cross-sectional geometry. A first lens device is supported in the fixture and movable into a position to interrupt the beam of light for selecting beam shape by altering the first projected beam shape from the first cross-sectional geometry to a second cross-sectional geometry different from the first geometry. The first lens device includes at least one lenticular lens element having lens lenticules oriented in a first direction. A second lens device, separate from the first device, is supported in the fixture and movable into a position to interrupt the beam of light for selecting beam shape by altering the second projected beam shape from the second cross-sectional geometry to a third cross-sectional geometry different from the first and second geometries.

Abstract: An image projector is provided with a light source and a light valve positioned downstream of the light source. An optical path is defined between the light source and the light valve. To accommodate various image viewing formats, a plurality of optical integrators is positioned between the light source and the light valve. Each of the plurality of optical integrators is movable laterally of the optical path and is positionable in the optical path. Light from the light source is transmitted to the light valve through the particular optical integrator positioned in the optical path. Each optical integrator is constructed to produce a unique display format for the light transmitted therethrough to the light valve, in order the accommodate different display formats such as standard and letter-box without wasting light.

Abstract: An illumination device for an interior space, such as that of a motor vehicle, for example, has a light source (2) and an opposing reflector system (3) located at a distance across the interior space, wherein the reflector system includes a reflector unit having multiple reflectors (8, 13, 14, 15, 16) each capable of being brought into a position in a beam path (7) of light from the light source (2). The light source (2) can be placed in a center control panel (4) of the motor vehicle, while the reflector system (3) can be placed on a vehicle ceiling located opposite the center control panel (4).

Abstract: A lighting apparatus includes a discharge arc lamp illumination source, an elliptical reflector completely surrounding the illumination source for collecting and projecting light from the illumination source, a shutter for dimming the amount of light generated by the illumination source and emanating from the lighting apparatus. The shutter is mechanically operable to defined an optical passageway therethrough of variable cross sectional area. The shutter includes a plurality of shutter blades mounted in a movable relationship relative to each other in response to user input. The shutter blades is movable to define the optical passageway of variable cross sectional area to dim the amount of light from the illumination source passing therethrough over the range of from about 0 to 100%.

Abstract: A highly compact, light weight automated luminaire is disclosed having a head unit mounted on a support structure which provides pan and tilt of the head unit. The latter includes beam controlling optics providing precise control over beam parameters including color. Groups of the instruments are remotely controlled from a digital controller such as a PC connected by cable or a wireless link to the instruments. The lights each include processors for processing comands from the digital controller. By reason of its light weight and compactness, the luminaire is suitable for many applications barred to conventional automated lighting fixtures.

Abstract: A compact and efficient theatrical light that includes four mirrors, a gobo apparatus a colorchanger/dowser/diffusion system, and a lens system. The light beam is reflected four times, each time by 90 degrees. The second reflection is perpendicular to the plane formed by the initial path of the beam and the path after the first reflection. The gobo, the lens system and the colorchanger/dowser/diffusion system are located between the second and the third mirrors. This achieves a very compact, but fully capable light which may be attached to and protected by a truss system when in use and when in transport.Also discussed is a simple color changer/dowser/diffusion system with color glass panels mounted to tracks and moveable into and out of the optical path by cables connected to each panel.

Abstract: The I-snoot includes a circular casing having side walls extending forwardly from the front wall. A hand grip is adjustably secured to a flat plate iris diaphragm inside the casing allowing a full range of light to pass through the light control blade diaphragm. The I-snoot assembly has a second casing located on the opposite end of the circular casing, having side walls extending forwardly from the back wall. The back wall casing has a metal lip that protrudes outwardly from the assembly which allows attachment to standard lighting units. A transition zone interconnecting the light control blades is located inside each outer casing. The assembly also contains a lighting accessory adaptor on the front wall casing to use various photographic accessories, such as barn doors, gels, and various screens to control lighting intensities and variations.

Abstract: An ellipsoidal reflector is provided for a light energy emitting lamp which is used as a heating element within an oven. Because an ellipsoidal reflector is used, the light energy emitting lamp may be positioned at the first focal point of the ellipsoidal reflector in order to concentrate light reflected by the ellipsoidal reflector on the food being cooked. Accordingly, a charbroiled surface effect common to gas or electric cooking grills is produced. The light energy emitting lamp may also be moved away from the first focal point so that light is reflected by the ellipsoidal reflector more uniformly.

Abstract: A dual reflector lighting system having an adjusting assembly for independently adjusting an inner reflector and an outer reflector relative to a gaseous discharge lamp. The lighting system includes a housing having a ballast assembly mounted therein. An elongated tubular adjusting member has one end thereof connected to the bottom of the housing. A lamp socket for receiving a gaseous discharge lamp is mounted to the other end of the adjusting member. The lamp socket is electrically connected to the ballast assembly. The system includes both an outer reflector and an inner reflector mounted coaxially about the gaseous discharge lamp. The outer reflector is mounted to the tubular adjusting member for movement relative thereto to adjust the outer reflector relative to the gaseous discharge lamp. The inner reflector is connected to the adjusting member for adjusting the inner reflector relative to the gaseous discharge lamp.

Abstract: A zoomable beamspreader is disclosed having two lenses arranged in closely spaced, confronting relationship, with each lens incorporating an array of alternating positive and negative lens segments. One of the two lenses is controllably movable relative to the other, in a direction substantially perpendicular to an optical axis, between a non-spread position, in which the positive and negative lens segments of one lens are aligned with the respective negative and positive lens segments of the other lens, and a spread position, in which the positive and negative lens segments of one lens are aligned with the respective positive and negative lens segments of the other lens. The two lenses can take any of several alternative forms, including a one-dimensional array of cylindrical lens segments, for providing a zoomable beamspread along just one dimension, and a two-dimensional array of spheric or aspheric lens segments, for providing a zoomable beamspread along both dimensions.

Abstract: An apparatus and associated method for projecting a light pattern onto a target object, wherein the light pattern has a generally uniform brightness with well defined boarders. The apparatus includes a fiber optic conduit that emits a beam of light along an optical path. Light emitted from a fiber optic conduit typically contains a central region of a predetermined brightness and a peripheral region, created by light interference patterns, where the light is less bright. A first adjustable optical diaphragm is disposed along the optical path proximate the fiber optic conduit. By selectively varying to aperture of the first optical diaphragm, the diameter of the beam of light propagated along the optical path can be controlled. A second adjustable optical diaphragm is disposed along the optical path a predetermined distance away from the first optical diaphragm.

Abstract: A lens for use in a light fixture provided to project a beam of light in a first light pattern having a first cross-sectional geometry. A lenticular lens element is supported in the fixture and movable into a position to interrupt the beam of light for selecting beam shape by altering the first projected light pattern from the first cross-sectional geometry to a second cross-sectional geometry different from the first geometry and for moving the second pattern to a desired orientation. The lens element may be carried by a disc rotatably mounted in the fixture. The disc may carry a plurality of lens elements which can also change the orientation of the projected light patterns.

Abstract: A module for use in a heating appliance has a frame with first, second, third, and fourth sides. A first heating lamp is mounted substantially along the first side of the frame, a second heating lamp is mounted substantially along the second side of the frame, a third heating lamp mounted substantially along the third side of the frame, and an fourth heating lamp is mounted substantially along the fourth side of the frame. Fifth, sixth, seventh, and eighth heating lamps are mounted substantially diagonally to the frame. A first reflector reflects radiant energy from the first heating lamp, a second reflector reflects radiant energy from the second heating lamp, a third reflector reflects radiant energy from the third heating lamp, and a fourth reflector reflects radiant energy from the fourth heating lamp. A fifth reflector reflects radiant energy from the fifth, sixth, seventh, and eighth heating lamps.

Abstract: A simple, reliable and yet fully capable wash light, having a lamp surrounded by a reflector, a field stop with a fixed aperture, a frame for holding color/diffusion/dowser panels, and a fernal lens located immediately adjacent the frame. These elements are mounted in a housing which, in turn, is mounted to a yoke allowing 270 degrees of tilt. The yoke is mounted to a base allowing 360 degrees of pan.

Abstract: A luminaire assembly has a housing including a number of circumferential slots in which the handles of shutter blades are arranged to be slidable. The edges of adjacent slots are radially overlapped around the circumference of the luminaire housing so that each handle may be manipulated over an angular range approaching or exceeding 360/n, where n is the number of slots and/or shutter blades.

Abstract: A studio lighting device for supplying light having a selected color temperature to a subject, comprising: an electrically powered light source connected to receive operating power which establishes a voltage across the source, the source being operative to produce light having a color temperature which varies as a function of the voltage; a first reflecting mirror for reflecting light in a first wavelength range, the first mirror being disposed at a location for reflecting a quantity of light from the source to the subject; a second reflecting mirror for reflecting light in a second wavelength range which is different from the first wavelength range, the second mirror being disposed at a location for reflecting a quantity of light from the source to the subject; and means connected for displacing the second reflecting mirror relative to the first reflecting mirror in order to alter the ratio between the quantity of light reflected to the subject by the first mirror and the quantity of light reflected to the

Abstract: A lamp used in photography and television comprising a housing having a filter cavity into which an optical element provided with a handle can be introduced, the housing having first and second shafts situated between two sidewalls of a holding device and extending in a longitudinal direction of the housing and bridging the filter cavity, the handle of the optical element is provided with first and second recesses which are arranged to engage the first and second shafts, respectively, the first shaft being surrounded by the first recess of the handle to allow the optical element to swing about the first shaft from a working position, in which the optical element is located within the filter cavity, into a second position in which the optical element is removed from the filter cavity and the second recess engages the second shaft, and a locking mechanism is provided for retaining engagement of the second recess with the second shaft when the optical element is in the second position.

Abstract: A moire effect light assembly for the enhancement of energizable lamps. The assembly includes a pair of moire effect grid patterns which are movable with respect to lamp as it is energized.

Abstract: A dimmer for variably adjusting light transmitted through it to a fiber optic bundle from a light source whose own intensity is not to be adjusted. A body has an axial passage for light to pass through. A plurality of opaque vanes is symetrically arranged in the passage. They meet at an apex located on the axis. Each vane has an axis of rotation in a plane normal to the axis and are rotatable to vary the amount of light which is transmitted. These vanes are coordinated for simultaneous and identical rotation.

Abstract: A lighting instrument having pivotable color filters arranged in a substantially radial arrangement with respect to a projected light beam. Multiple sets of such filters are spaced along the axis of the light beam to vary the color of the light beam emitted from the instrument. A motorized mechanism rotates each filter of each set in synchronization with each other and independently with respect to filters of the other sets. The filters may be rotated by the motorized mechanism through flexible coupling mechanisms. The filters also may be positioned to pass unfiltered light to vary the saturation of the light beam.

Abstract: A lighting instrument having pivotable dichroic filters arranged in a substantially radial arrangement with respect to a projected light beam. Multiple sets of such filters are spaced along the axis of the light beam to vary the color of the light beam emitted from the instrument. A gearing mechanism rotates all filters of each set in synchronization with each other and independently with respect to filters of the other sets. The filters may be positioned to pass unfiltered light to vary the saturation of the light beam.

Abstract: An optical arrangement for high-powered projectors has a metal vapor lamp integrated into an ellipsoidal mirror, and an additional mechanical light valve for the continuous control of brightness of the stream of light, and is especially for use in multi-, super-shuttered and large projectors. The compact structure offers high optical efficiency and, at the same time, slight technical expense. The use of this technology makes possible the production of high-powered diaprojectors with small dimensions and light weight.

Abstract: A horticultural luminaire in which a lamp is contained within a first compartment and a ballast unit is contained in a second compartment. The ballast unit is in heat-conducting contact with the top of the unit and a plate member also covers the ballast unit to act as an additional heat sink. The top of the luminaire housing may be provided with bracket members to facilitate mounting of the luminaire on a structural I-beam.

Abstract: A space lighting fitting comprises a support, lamp holder means and light directing means adjustable between first and second positions giving direct and indirect lighting respectively.

Abstract: A tambour-type panel of sections movable in a U-shaped track system from a side location in a housing to a location in the path of light. The panel sections are constructed to diffuse light passing therethrough. Each section of the diffusing panel has a texturing which diffuses the light with different degrees.

Abstract: A sunlight simulator includes an elongated, cylindrical housing, an artifical light source disposed along the longitudinal axis thereof, and a plurality of light collecting subassemblies equidistantly spaced radially from and around the light source. The light source is of a type that emits a substantial amount of radiation in the UV portion of the spectrum. The light collecting subassemblies provide a plurality of individually and selectively adjustable beams of UV radiation. A plurality of light guides are provided for directing the radiation to desired locations.

Abstract: A color changer system mounted at the light beam emission end of a luminaire. The system includes a support frame secured to the housing and disposed transverse to the beam, a plurality of iris units each having a plurality of colored, translucent leaves rotatably attached to the support frame, and a circular control plate rotatably mounted to the support frame and having a control slot in which a thrust pin of each leaf is slidably movable and a control handle. The support frame and the control plate each have circular apertures with centers that are aligned with the beam axis. When the control plate is rotated, the leaves of each iris unit open or close in response to pressure against the thrust pin so as to control the coloring of the light beam.