Abstract: An illumination optical system include a first lens array including multiple lens cells that split a light beam emitted from a light source into multiple light beams, a second lens array including lens cells that the light beams split by the lens cells of the first lens array are incident thereon, and an optical element configured to illuminate an image display element by superposing light beams emerging from the second lens array on the image display element. At least one of the first lens array and the second lens array includes at least two lens cells each having a curved surface that is formed so as to be continuous with a curved surface of an adjacent lens cell, the at least two lens cells being decentered, and at least two lens cells of the first lens array have different radii of curvature.

Abstract: A laser light source apparatus includes: a laser light source that emits a laser beam; a condenser lens that converges the laser beam emitted from the laser light source; and a light guide unit that propagates and outputs the laser beam converged by the condenser lens, and the laser beam converged by the condenser lens is made incident at an angle other than perpendicular to an incident end face of the light guide unit.

Abstract: A display module includes a light emitting element array and a lens array. The light emitting element array includes a plurality of light emitting elements arranged on a substrate and driven by driving signal to emit light. A lens array is configured to focus light emitted by the respective light emitting elements. The lens array includes a plurality of first lens pillars respectively provided on the light emitting elements, a plurality of second lens pillars respectively provided on the first lens pillars and having curved surfaces at tops thereof, and a plurality of lens portions formed so as to cover the first lens pillars and the second lens pillars, the lens portions having curved surfaces at tops thereof. A driving circuit is provided on the substrate.

Abstract: A projection optical system substantially consists of a first optical system composed of a plurality of lens groups and a second optical system composed of one reflection mirror having a convex aspherical surface arranged in this order from the reduction side, in which all optical surfaces constituting the first and second optical systems are formed so as to have rotationally symmetrical shapes around one common axis, the projection optical system is configured such that focus adjustment is performed by individually moving two lens groups in the first optical system along the common axis, and the lens disposed on the most magnification side in the reduction side lens group of the two lens groups is a lens having a convex surface on the magnification side, thereby magnifying and projecting an image formed on a conjugate plane on the reduction side to a conjugate plane on the magnification side.

Abstract: The light source device includes: a first support that supports one of a light source and a collimator lens condensing; a second support that supports the other of the light source and the collimator lens; and a fixing member that fixes the first support to the second support. The first support includes a first protruding portion that protrudes from the first support toward the second support, the first protruding portion having a through hole therethrough. The second support includes a second protruding portion that protrudes from the second support toward the first support, the second protruding portion having: a receiving portion that receives the first protruding portion; and a receiving hole. A rod portion of a locking member is inserted into the through hole and the receiving hole, and a head portion of a locking member is sealed with a sealant.

Abstract: There is provided a laser projector, including: a laser source section for emitting laser beams; a spatial light modulator which modulates the laser beams to generate image light; a projector lens from which the image light is emitted; a beam shaper which shapes the laser beams into a shape of the spatial light modulator; and a pupil uniformizer which makes a light intensity distribution uniform at an exit pupil of the projector lens, wherein the pupil uniformizer is situated between the laser source section and the beam shaper.

Abstract: A projection display includes at least one light source, at least one reflective image generator configured to represent frames in a two-dimensional distribution of subareas of same, a projection optics arrangement having a two-dimensional arrangement of optical projection elements and being configured to image an associated subarea of the at least one image generator onto an image plane in each case, so that images of the frames superimpose within the image plane to form an overall picture, and at least one beam splitter arranged within an optical path between the at least one reflective image generator and the two-dimensional arrangement of optical projection elements, on the one hand, and the optical path between the at least one light source and the at least one reflective image generator, on the other hand.

Abstract: A message display that produces a visible message by projecting an image on a surface such as a wall or floor. A bright light source is provided, preferably including an array of light emitting diodes (“LED's”). The light from this bright source is passed through one or more lenses in a condenser assembly to make it more uniform. The light then passes through an image plate that contains a small version of the image to be displayed. Once the light passes through the image plate it next passes through a focusing assembly. The focusing assembly creates a desired projected image on a target surface such as a wall or floor. The projected image is a representation of the image contained on the image plate.

Abstract: A projection display having at least one light source and also regularly-disposed optical channels. The optical channels comprise at least one field lens, to which respectively one object structure to be imaged and also at least one projection lens are assigned. The distance of the projection lenses from the assigned object structures corresponds to the focal distance of the projection lenses while the distance of the object structures to be imaged from the assigned field lens is chosen such that a Köhler illumination of the assigned projection lens is made possible. Then the individual projections are superimposed to form the total image.

Abstract: A light projector for operation during a show that contains theatrical haze. The light projector may include a light source, a lens, a fan, and a housing having an inner chamber. The lens may have a first side and a second side. The first side of the lens may be contained within the inner chamber of the housing. The second side the lens may be outside of the inner chamber of the housing. The fan may be configured to be operated to generate air flow inside the inner chamber of the housing. A substantial portion of the air flow may be directed to impinge upon the first side of the lens to cause de-fogging of theatrical haze condensate on the first side of the lens.

Abstract: The invention provides a projection system and a light-homogenizing device adjustment element for adjusting the position of a light-homogenizing device. The light-homogenizing device adjustment element has an actuator, and the actuator leans against one side of the light-homogenizing device and has a plurality of curved surfaces with different radii of curvature. When the actuator rotates, different curved surfaces push the light-homogenizing device to cause the light-homogenizing device to move in at least one direction from an initial position.

Abstract: An optical projection system for projecting an enlarged image on a projection surface is provided. The optical projection system includes an image forming element, a coaxial optical system and a concave mirror. The coaxial optical system and the concave mirror are arranged in this order on an optical path from the image forming element to the projection surface. The coaxial optical system includes lens groups and an aperture stop that share an optical axis. The lens groups include a first lens group and other lens groups. The first lens group has negative refractive power and independently moves in an optical axis direction for adjusting the focus of the optical projection system. The aperture stop is arranged at a position closer to the image forming element than the first lens group that is arranged closest to the concave mirror among the lens groups having the negative refractive power.

Abstract: An optical device includes a high pressure discharge lamp, a concave condensing mirror placed so as to surround the high pressure discharge lamp while an optical axis stays extended along a direction of an arc of the high pressure discharge lamp, and an aspherical lens that is placed forward the light exit direction of the concave condensing mirror and that is rotationally symmetrical with respect to the optical axis of the concave condensing mirror, in which a reflecting surface of the concave condensing mirror is configured so as to have a shape set in connection with the shape of a light incident surface and the shape of a light exit surface of the aspherical lens.

Abstract: A projection lens of an imaging module and the imaging module are provided. The imaging module further has a light modulator to project a first image with a first aspect ratio. The projection lens comprises an anamorphic lens set and a projection lens set. The anamorphic lens set comprises a first cylinder lens, a second cylinder lens, a bi-convex cylinder lens and a bi-concave cylinder lens, which are set after the light modulator in sequence. The first cylinder lens has at least one flat surface, and the second cylinder lens has at least one convex surface. The anamorphic lens set projects the first image with the first aspect ratio into a second image with a second aspect ratio; the second aspect ratio is different from the first aspect ratio. The projection lens set receives and projects the second image with the second aspect ratio.

Abstract: An illumination optical system is configured to illuminate an optical modulator configured to modulate incident light and includes a condenser lens system that includes a meniscus lens with a concave on a light source side, and condenses light from a light source; and a spherical aberration corrector disposed on an optical modulator side of the condenser lens system. The illumination optical system satisfies: 0.6<|f/L|<1.4 0.9<sin ??1.0 where f is a focal length of the condenser lens system, L is a length from an object-side principal point of the condenser lens system to the light source, and ? is half an angle at which the condenser lens system takes in the light from the light source.

Abstract: An illuminating unit and a display apparatus including the illuminating unit are provided. The illuminating unit generates and emits light to a display element of the display apparatus, and includes a light source; a uniformizing unit which uniformizes light from the light source and includes a plurality of uniformizing lenses arranged on an optical path; a condensing unit which condenses light from the uniformizing unit to emit the light to the display element and includes a plurality of condensing lenses sequentially arranged on the optical path, and the uniformizing unit and the condensing unit are arranged based on a width of one of a plurality of cell lenses forming the uniformizing lens and a width of an image displayed in the display element.

Abstract: Disclosed is a projector, the projector including a light source, an illumination unit illuminating light incident from the light source, and a display device enabling to realize an image by receiving the light irradiated from the illumination unit, and whose center is positioned at an axis different from an optical axis of the illumination unit.

Abstract: A projector includes a light source device which emits an illumination light; an aperture disposed with a tilt with respect to a plane perpendicular to a center axis of the illumination light, provided with an opening section which transmits a part of the illumination light, and block a rest of the illumination light; a pair of first and second lens arrays which divides the illumination light from the light source device into a plurality of partial light; and an overlapping lens which overlaps the illumination light transmitted through the first and second lens arrays, wherein the aperture is disposed on a light path between the light source device and the overlapping lens.

Abstract: Disclosed are a projection display apparatus and a projection optics provided in the projection display apparatus. The projection optics has a refractive optics and a reflective optics. In the refractive optics, a lens (non-circular lens) provided on a reflective optics side has a non-circular shape forming part of an imaginary circular region whose center is an optical axis center of the refractive optics. In other words, the non-circular lens has a shape of a cut-out portion of an imaginary circular lens having an optical axis center coinciding with the optical axis center of the refractive optics.

Abstract: A projection type image display apparatus in which shortening of the projection distance (widening of the angle of view) and miniaturization of the projection optic system are realized is provided. It comprises, in a traveling direction of the light, an image display element, a lens group including a plurality of lenses, a first lens, a second lens, and a mirror to reflect light emitted from the second lens to be projected obliquely on a screen in this order. The refractive power of the first lens is positive and the refractive power of the second lens is negative. The first and the second lenses are moved in an interlocked relationship with each other along an optical axis of the lens group and a movement amount of the first lens is made larger than a movement amount of the second lens.

Abstract: A collimator lens unit includes at least two lenses and substantially collimates a beam of light emitted from a solid-state light source unit of a Lambert emission type, wherein at least two faces of incidence faces and emission faces of the lenses constituting the two lenses are aspheric faces, one front aspheric face located close to the solid-state light source unit has a function of changing a luminous flux density distribution of the beam of light emitted from the solid-state light source unit to a predetermined luminous flux density distribution in which the luminous flux density in the vicinity of an optical axis of the collimator lens unit is higher than the luminous flux density in a peripheral portion separated from the optical, the rear aspheric face farthest from the solid-state light source unit has a function of substantially collimating the beam of light.

Abstract: A projector including a light source unit, a lens integrator system, a light modulator having an image formation region where light from the lens integrator system is modulated in accordance with image information, and a projection system that projects light from the light modulator, wherein the projection system is so disposed that the optical axis of the light incident on the projection system is shifted from the optical axis of the projection system in a predetermined direction when the projection system is viewed in the direction in which the light travels toward the projection system, and the lens integrator system is so configured that illuminance of the light on a first side corresponding to the predetermined direction in the image formation region is higher than illuminance of the light on a second side that is opposite the first side.

Abstract: The illumination optical system includes, as optical elements, a condenser lens system (3) to condense light from a light source (1), a first fly-eye lens (5) and a second fly-eye lens (6). The light source generates a light emitter having a finite longitudinal length in a first direction orthogonal to an optical axis direction of the illumination optical system. The light source and the optical elements are configured to form the light source images closer to the illumination surface than the second fly-eye lens. The light source and the optical elements are configured to satisfy a condition of P2/P1?2.0. In the condition, P1 represents an array pitch of the light source images in the first direction, and P2 represents an array pitch of the light source images in a second direction orthogonal to the first and optical axis directions.

Abstract: A plurality of light source sections each have a reflector and a light source that is a discharge lamp. The plurality of light source sections are in a positional relationship wherein all reflector center axes are orthogonal to each other and at least one reflector center axis is orthogonal to the optical axis of a projection optical system. Interchange means interchanges the locations of the plurality of light source sections when a light source section needs to be replaced. Reflection means guides, to a converging optical system, light from that light source section whose reflector center axis is perpendicular to the direction of gravity.

Abstract: A projection-type display apparatus that projects an image on a screen and performs image display includes at least one laser source that emits a coherent light beam, an illuminating optics that propagates the light beam emitted from the laser source into a predetermined optical path to guide the light beam to the screen, a reflective optical modulator that forms the image to be displayed on the screen on an illuminated surface illuminated by the light beam guided by the illuminating optics, and a projection optics that magnifies and projects the image formed on the illuminated surface of the reflective optical modulator on the screen. The illuminating optics includes a diffusion device, which diffuses the propagated light beam, and is arranged on a light propagation path near a conjugated position with the reflective optical modulator.

Abstract: A projection display satisfies formulas {(4FR?)/(W?TphR)}?0.015 and W??0.5, where: F is an F-number of a projection lens; W? is a diagonal size (inch number) of a light modulation element; ph is a pixel count in one side direction of the light modulation element; T is a throw ratio of the projection display (=a projection distance s/a distance L in the one side direction of a projected image on a projection plane); R is a radius of an exit pupil of the projection lens; I is an integrated light quantity obtained by, in a light quantity distribution in the exit pupil, radially integrating the light quantity up to the radius R; and I?(=I/2) is an integrated light quantity obtained by, in the light quantity distribution in the exit pupil, radially integrating the light quantity up to a predetermined radius R? about barycenter of the light quantity distribution.

Abstract: An imaging light source module that includes a plurality of light guides, a plurality of light emitting sources, and an intermediate image surface is disclosed. Each of the plurality of light guides has an entrance face, an exit face, and at least one side wall, and all of the light guides are capable of delivering light along associated light distribution axes intersecting a common reference point. Each of the plurality of light emitting sources delivers light only to a single light guide of the plurality of light guides. The intermediate image surface comprises a plurality of pixels, where each pixel receives light from the exit face of a single associated light guide of the plurality of light guides.

Abstract: A light source device includes: a first light source configured to emit a first source light in a first wavelength range; a source light generator configured to generate, from the first light, a color-varying source light having time varying color; a second light source configured to emit a second source light in a second wavelength range that is different from the first wavelength range; and a light source controller configured to control driving timing for turning on and off each of the first light source and the second light source so as to cyclically select one of the color-varying source light and the second source light to be output as an output source light.

Abstract: A light-emitting device includes a circuit board, a light-emitting element, a light-condensing element, and a glue. The circuit board has through holes, a first surface, and a second surface. The through hole has a first pathway and a second pathway. The first pathway extends from the first surface into the circuit board. The second pathway extends from the second surface into the circuit board and communicates with the first pathway. An accommodating space of the second pathway is greater than that of the first pathway. The light-emitting element is disposed on and electrically connected to the first surface. The light-condensing element has positioning posts. A portion of the light-condensing element is disposed on the light-emitting element. The positioning post passes through the first pathway and is located inside the second pathway. The glue is disposed in the second pathway for fixing the positioning posts in the through hole.

Abstract: A light source module is disclosed. The light source module includes an emitter having a light emitting surface, a solid integrating optic aligned to accept light emitted from the emitter at an entrance face and deliver light to an exit face, and a lens aligned to receive light from the exit face. The lens has a substantially hemispherical portion having a radius of curvature and the exit face of the solid integrating optic has an exit face diagonal. The ratio of the radius of curvature to the exit face diagonal is greater than 0.7. The solid integrating optic and the lens each have an index of refraction, and the ratio of the lens index of refraction to the solid integrating optic index of refraction is greater than unity.

Abstract: A projection display device having a projection device projecting an image on a surface, and a position detection function of detecting an object's position between the surface and the projection device, includes: a light source emitting light beams toward the object; a light detector detecting the light beams reflected by the object; and a position detector detecting the object's position in an imaginary plane based on the light detector's result, wherein the light source emits, as the light beams, first through third light beams having first through third intensity distributions, the second intensity distribution having a highest intensity at a position failing to overlap a highest intensity of the first intensity distribution, and the third intensity distribution having a highest intensity portion at a position failing to overlap a straight line connecting the highest intensity portions of the first and second intensity distributions.

Abstract: An object of the present invention is to provide illumination optics that enables improvement in brightness and reestablishment of an irradiation state which is provided with illumination light and which corresponds with a display area, and is to provide illumination optics including a first fly-eye lens and a second fly-eye lens where emission light from the first fly-eye lens enter, wherein at least one of lens elements configuring the second fly-eye lens covers an irradiation area smaller than an irradiation area provided by the second fly-eye lens.

Abstract: A light source device, includes: an arc tube, and a pair of sealing portions; a reflector; and a sub mirror configured to reflect the light emitted from the arc tube toward the arc tube, and disposed of the other side of the sealing portion in such a manner as to cover a part of the outer surface of the tube spherical portion of the side of the illumination area, the sub mirror include a plurality of reflection members provided with reflection surfaces having different shapes, and the distance between the illumination axis and the outer shape of one of the adjoining reflection members is different from the distance between the illumination axis and the other of the adjoining reflection members.

Abstract: Disclosed is an image reading device configured to read information of an object, including an imaging optical system configured to image an image of an object and an image-capturing device configured to image-capture at least a portion of the image imaged by the imaging optical system, wherein the imaging optical system includes a first optical system configured to image an intermediate image of the object and a second optical system configured to image the imaged image of the intermediate image.

Abstract: A display device includes a projector, a Fresnel lens converting a projected light from the projector into a nearly parallelized light, a screen with light reflectivity on which an image by the projected light from the projector is generated, and a retrotransmissive material forming another image of an image located on one side of an element plane in a position in a space on the other side of the element plane such that the image and the other image are symmetric with respect to the element plane. The retrotransmissive material forms an image by a light that has obliquely entered the element plane, such that a position from which the light has obliquely entered the element plane and a position in which the image is formed are symmetric with respect to the element plane, and thereby forms a real image of the image on the screen.

Abstract: An illumination system and a projection device comprising the same are provided. The projection device comprises an imaging system and the illumination system. The illumination system comprises a first light source, a dichroic element, at least one condensing element, a rotary wheel and a light integrating element. The first light source provides a first wave band light, and the rotary wheel has at least one wave band transforming area and a reflecting area. After passing through the dichroic element and the at least one condensing element, the first wave band light will be focused onto the at least one wave band transforming area to be transformed into a second wave band light or be focused onto the reflecting area that will be reflected. The second wave band light and the reflected first wave band light will be focused on the light integrating element by the at least one condensing element.

Abstract: An illuminating optical system includes: a substantially rectangular-shaped light source that includes a light emitting surface with a split pattern formed thereat by a splitting line, the splitting line extending along a predetermined direction and splitting the light emitting surface into a plurality of separate areas; an illumination-target member that includes a rectangular radiation-target area; and an optical member in that condenses light departing the light emitting surface and radiates the condensed light toward the radiation-target area, wherein: an extent of uneven illumination attributable to an image of the split pattern at the light emitting surface of the light source, formed at the illumination-target member, is reduced.

Abstract: The lighting unit includes the DMDs (80R), (80G), and (80B). The lighting unit also includes: the prisms (50) and (60) combining the light emitted from the DMDs (80R), (80G), and (80B); and the light modulating optical device (90G). The incident light including the green component light and the yellow component light enters the light modulating optical device (90G). The light modulating optical device (90G) transmits the green component light and changes a transmittance of the yellow component light depending on a change of a molecular state. Light having emitted from the light modulating optical device (90G) enters the DMD (80G), which corresponds to the incident light.

Abstract: A polarization element includes: a substrate; a plurality of convex line sections on one surface of the substrate and forming stripes in a plan view; and a multilayer thin line provided to each convex line section and extending along the convex line sections, wherein the multilayer thin line has a lower layer on the convex line section, and an upper layer stacked on the lower layer, the lower layer and the upper layer each have a first thin line on one side surface in a direction along a shorter dimension of the convex line section, and a second thin line on the other side surface, the materials of the lower layer first thin line and the upper layer first thin line are different from each other, and the materials of the lower layer second thin line and the upper layer second thin line are different from each other.

Abstract: The illumination optical system includes an integrator configured to divide light from a light source into plural light fluxes, and a collection optical system configured to collect the plural light fluxes from the integrator toward an illumination surface. A rear principal point of the collection optical system is located closer to the light source than a front principal point of the collection optical system. The configuration provides a compact illumination optical system which brightly illuminates the illumination surface with the light and enables high contrast image projection.

Abstract: A projection apparatus includes a light source, a light valve, a light uniforming device, and a lens module. The light source provides an illumination beam. The light valve on a transmission path of the illumination beam converts the illumination beam into an image beam. The light valve has an active surface with a rectangular shape. The light uniforming device is between the light source and the light value. The lens module is between the light uniforming device and the light value. A refractive power of the lens module along a first direction is different from a refractive power of the lens module along a second direction. An f-number of the illumination beam along a direction parallel to a long side of the active surface of the light valve is greater than an f-number thereof along a direction parallel to a short side of the active surface of the light valve.

Abstract: The invention discloses a projecting system. The projecting system includes two sets of lens. The first set of lens has a first focal length for focusing an incident ray of light to form a first image. The second set of lens has a second focal length for projecting the first image to form a second image. The two sets of lens are separated by a lens-apex distance relative to the light path between the two sets of lens. The second focal length is smaller than or equal to the lens-apex distance. A difference between the second focal length and the lens-apex distance is smaller than or equal to a half of the first focal length.

Abstract: In a projection type display apparatus using plural light sources, an optical unit including plural light sources, a first collimator lens, an optical coupling lens, an image display element and a projection lens is formed, and in an optical path extending from the light sources to the projection lens, light is condensed only once on the image display element, thereby minimizing the number of optical parts used and shortening the length of the optical path from the plural light sources up to the projection lens to attain the reduction in size of the projection type display apparatus or the optical unit. In this way it is possible to provide a projection type display apparatus or an optical unit each capable of attaining the reduction of cost by minimizing the number of optical parts used and capable of attaining a high luminance by irradiating the image display element with the light emitted from the light sources without leakage of the light.

Abstract: A light source that emits light includes light source units, each emitting a plurality of light beams parallel to one another, the plurality of light beams including first and second light beams, and a beam distance adjustment element that is an optical element made of a light-transmissive material. The beam distance adjustment element is configured to adjust the distance between the first and second light beams. The beam distance adjustment element includes a first incidence plane on which the first light beam is incident, a first exit plane that is parallel to the first incidence plane and from which the first light beam exits, a second incidence plane on which the second light beam is incident, and a second exit plane that is parallel to the second incidence plane and from which the second light beam exits. The first and second light beams intersect in the beam distance adjustment element.

Abstract: An illuminating unit and a display apparatus including the illuminating unit are provided. The illuminating unit generates and emits light to a display element of the display apparatus, and includes a light source; a uniformizing unit which uniformizes light from the light source and includes a plurality of uniformizing lenses arranged on an optical path; a condensing unit which condenses light from the uniformizing unit to emit the light to the display element and includes a plurality of condensing lenses sequentially arranged on the optical path, and the uniformizing unit and the condensing unit are arranged based on a width of one of a plurality of cell lenses forming the uniformizing lens and a width of an image displayed in the display element.

Abstract: An LED light shaping device and illumination system are provided. According to one embodiment, a light shaping lens is configured to shape light emitted from a light source and direct the light on a display panel for projection. The light shaping lens comprises a light input surface configured to receive light emitted from the light source a reflective surface configured to reflect at least part of the light received by the light source; and a light output surface having a first curvature in a first direction and a second curvature in a second direction, wherein the light output surface is configured to emit the light that is received by the light input surface and reflected by the reflective surface, and wherein the first curvature and the second curvature are configured to shape the light such that the emitted light has an oval cross section.

Abstract: A method and apparatus for a projection display system includes a spatial light modulator and a volume illumination hologram. The spatial light modulator comprises a digital micromirror device, and the projection system includes a laser light source to produce a sequence of collimated, colored, light beams for the illumination hologram. Waste light produced by the spatial light modulator is transmitted to the illumination hologram, and the illumination hologram emits waste light from at least one of its edges. Waste light emitted from an edge of the illumination hologram is absorbed by a light sensor to control the intensity of the light beams. A projection focusing element is mounted proximate a side of the illumination hologram to focus the image beam from the spatial light modulator for viewing. A projection hologram is interposed between the side of the illumination hologram and the projection focusing element to manage waste light.

Abstract: A display panel includes an array of refractive elements arranged on a substrate. The array is positioned to receive light of a first intensity profile and configured to transmit in a second intensity profile at least some of the light received. The display panel also includes a diffuser positioned to receive the light transmitted by the array of refractive elements and configured to transmit in a third intensity profile at least some of the light received. The second intensity profile has a lower relative intensity normal to the substrate than has the first intensity profile.

Abstract: A projection optical system including a first optical system configured to form a second image conjugate to a first image and a second optical system configured to include a reflective optical element which reflects light from the second image and to project a third image conjugate to the second image onto a projection surface is provided, wherein the first optical system includes a stop and at least one optical element with a positive refractive power and at least one optical element with a negative refractive power which are provided between the stop and the second image, and an optical element with a strongest positive refractive power in the at least one optical element with a positive refractive power is provided between the stop and an optical element with a strongest negative refractive power in the at least one optical element with a negative refractive power.

Abstract: A projection system includes a light source module illuminating a plurality of monochromic lights, at least one optical modulator modulating the lights illuminated by the light source module according to each of color signals, a color combining prism combining the monochromic lights modulated by the optical modulator to form an image, and a projection lens projecting the image formed by the color combining prism toward a screen. A semiconductor diode including a P type semiconductor layer, an intrinsic semiconductor layer, and an N type semiconductor layer to absorb or transmit the monochromic lights according to the value of a reverse bias voltage is arranged in units of pixels.