Abstract: An image projecting apparatus having an optical switch of a non-square matrix structure, is provided. A light source emits a plurality of monochromatic lights having different wavelengths. A first light transmission unit includes of a plurality of optical fibers that allows monochromatic lights to be passed therethrough. An optical switch unit has a plurality of non-square matrix type reflecting mirrors to selectively reflect the monochromatic lights. The reflecting mirrors includes a first group placed at odd lines and a second group placed at even lines. A square-beam generation unit converts reflected monochromatic lights into square beams, and a panel transmits the monochromatic lights converted into square beams and forms monochromatic signals of a predetermined size.

Abstract: There is provided a field-sequential color displaying method capable of reducing color breakup with respect to an optional image without greatly increasing a sub-field frequency. The field-sequential color display method includes; time-sequentially displaying of luminous information of an input image information with every display color and changing the display color in synchronism with the displaying of the luminous information in order to display the input image information, wherein one frame period in which one color image is displayed includes at least four sub-field periods in which information of each color is displayed, and a picture signal displayed in at least one sub-field period is a non-three-primary color picture signal which is generated from at least two primary color signals of input picture signals including three-primary color signals.

Abstract: A liquid crystal polarization rotator device is able to rotate polarization fast enough to compensate polarization mode dispersion. The amount or degree of rotation is rapidly reconfigurable. The device includes a cavity filled with a nematic liquid crystal material. The cavity has electrodes on a first face, e.g., a first substrate, and electrodes on a second face, e.g., a second substrate, opposite the first face. The electrodes are shaped and positioned to produce an electric field across the cavity capable of rotating the alignment direction of the molecules of the liquid crystal material in the cavity. The electrodes are patterned on the ends of optical fibers. Aligning and positioning of the electrodes on the ends of the optical fibers with a predetermined spacing forms the cavity that is filled with the nematic liquid crystal material. The filled cavity is a so-called liquid crystal microcell wave plate.

Abstract: A color projection system includes a lamp and at least one diffraction grating or at least one prism that diffracts light from the lamp onto an LC microdisplay panel. By moving either the at least one diffraction grating or the at least one prism with respect to the incident light from the lamp, the diffracted light received by the LC microdisplay panel sequentially comprises red, green, and blue light.

Abstract: A DMD (4) as a image display device time divisionally displays channel images formed by separating an image into RGB channels. A white light emitted from a xenon lamp (1) is separated, by an acousto-optical element (3), into spectal components. Those spectal components are projected onto the DMD (4). A refractive index of the acousto-optical element (3) varies with a frequency of an ultrasonic wave applied thereto. Therefore, a color of the spectral component applied to the DMD (4) may be changed by varying the refractive index of the acousto-optical element. RGB monochromatic lights may be irradiated on the DMD (4) by setting the frequencies FR, FG, FB of the ultrasonic wave at appropriate values.

Abstract: In a color image projection apparatus using a color wheel to illuminate a spatial optical modulator with light in color sequence, light reflected from the color wheel is added to light having passed through the color wheel, and the combined light is spatially modulated by the spatial optical modulator to form an image. If the light reflected a the incident surface of the color wheel is guided to the exit surface of the color wheel, and combined with the light having passed through the color wheel, the light utilization efficiency is improved. Any type of images can be projected with improved brightness.

Abstract: A projection system including a light source, a rectilinearly reciprocating cylindrical lens array, an optical separator, a light valve, and a projection lens unit. The light source emits a beam. The rectilinearly reciprocating cylindrical lens array advances color beams along different paths upon reciprocation. The optical separator separates the beam emitted from the light source into color beams according to wavelength. The light valve receives the scrolled color beams transmitted by the cylindrical lens array and forms a color image by pixels turning on or off according to an input image signal. The projection lens unit magnifies the color image formed on the light valve and projects the magnified color image on a screen.

Abstract: An illuminating apparatus has a light source emitting illumination light; and a prism having a plurality of reflecting surfaces and reflecting the illumination light from said light source by the reflecting surfaces to thereby bend an illumination optical path at an obtuse angle.

Abstract: A system for enhancing the quality of an image on a screen is provided. The system typically includes an illumination source configured to produce light and direct such light along an optical path, and a time-varying focus device disposed in the optical path and configured to periodically alter incident light to enhance the quality of the image on the screen.

Abstract: An apparatus is disclosed comprising a lamp which produces a first light which may be a white light; a first light valve, a second light valve, a first color separator, and a first aperture device. The first color separator receives the white light from the lamp, and separates the white light into a first color light and a first residual light. The first aperture device receives the first color light and the first aperture device can be controlled to modify a frequency of the first color light to the first light valve. The second light valve receives at least a portion of the first residual light. The first aperture device could also be controlled to substantially block at least a portion of the first color light.

Abstract: A single-panel color image display apparatus realizing a wide color gamut is provided. The single-panel color image display apparatus includes a colored light separator having a plurality of dichroic filters in which a dichroic filter reflecting a red light beam may be disposed lastly among the plurality of dichroic filters. The single-panel color image display apparatus may include a scrolling unit having a mask at a boundary portion between spiral lens cells.

Abstract: An illuminating-light controller includes a light modulator for projecting light on a corresponding area by tilting a reflecting surface. A first light source emits a first light that is projected on the corresponding area by illuminating the first light to the reflecting surface of the spatial light modulator being tilted at a first angle. A second light source for emits a second light that is projected on the corresponding area by illuminating the second light to the reflecting surface of the light modulator being tilted at a second angle. Still further, included is a control section for controlling the first light emitted from the first light source and the second light emitted from said second light source.

Abstract: A system and method for using pulses of laser light delivered in a non-overlapping sequence of first pulses at a green wavelength, second pulses at a blue wavelength and semi-continuous pulses at a red wavelength to illuminate a color generation unit for generating a color. Typically, the color generating unit is an image generating unit for producing color images and is equipped with transmissive or reflective pixels which are adjusted to select portions of the laser light generated at the green, blue and red wavelengths to obtain a desired output color. The first and second pulses preferably have a narrow pulse width and an interpulse separation equal to at least 100 times the narrow pulse width, while the semi-continuous pulses at the red wavelength have a wide pulse width equal to at least 100 times the narrow pulse width.

Abstract: A display device adopting a single liquid crystal display (LCD) panel, by which a decrement in luminance is reduced using only a single liquid crystal device, is provided. Accordingly, a degradation in color saturation due to an increase in luminance caused by the addition of an achromatic color is compensated for by a four-color conversion algorithm, even when an image is displayed using a single LCD panel or a ferroelectric liquid crystal (FLC) panel. Hence, the brightness of a screen increases compared to the prior art, and more distinct colors can be displayed.

Abstract: A new method for phase locking the color wheel in a color field-sequential projection display. At periodic interrupts, the method determines which color wheel index mark should be driven into coincidence with the Vsync signal. It does this by measuring the delay between Vsync and any index mark and then based on the current state of the spoke-sync counter and this delay value, a new next state is determined to drive the nearest index mark to Vsync to the Vsync position. At worst case this technique requires only one-half a color wheel revolution of phase correction to re-lock the system when the TV channel is changed and for the 5/2 and 7/2 spoke-sync modes, popular 50 Hz and 60 Hz modes, only one-quarter revolution of phase correction of the color wheel is required for re-lock.

Abstract: A system for enhancing the quality of an image on a screen is provided. The system typically includes an illumination source configured to produce light and direct such light along an optical path, and a time-varying focus device disposed in the optical path and configured to periodically alter incident light to enhance the quality of the image on the screen.

Abstract: Micro-electromechanical display device (“MDD”)-based multimedia projectors (90, 120) of this invention employ an arc lamp (32), a color modulator (42), and anamorphic illumination systems (94, 121) for optimally illuminating a MDD (50, 76) to improve projected image brightness. MDDs employ off-axis illumination wherein incident and reflected light bundles are angularly separated about a hinge axis (78, 110) and the MDD is illuminated by the anamorphic illumination systems of this invention having a slow f/# parallel to the hinge axis and a faster f/# perpendicular to the hinge axis. The resulting anamorphic light bundles (86, 88, 112, 114) illuminate and reflect more light into and off the MDD and through a fast f/# projection lens.

Abstract: State of polarization detectors and polarization control systems are disclosed. For example, the invention features an integrated optical assembly including: (i) a series of polarization-sensitive interfaces defining an optical beam path for an input optical beam to pass through the assembly, wherein each polarization-sensitive interface derives a sample beam from the input beam; and (ii) one or more retardation layers each positioned between a different pair of the polarization-sensitive interfaces, wherein the retardation layers are integrally coupled with the polarization-sensitive interfaces, and wherein the retardation layers and polarization-sensitive interfaces cause each sample beam to have an intensity that provides different information about the state of polarization of the input beam.

Abstract: A display apparatus projects a two dimensional image onto a display screen and includes illumination optics, a light modulator, separating optics and scanning optics. The light modulator is optically coupled to the illumination optics such that in operation the illumination optics illuminate the light modulator with an off-axis illumination and further such that the light modulator directs light onto an optic axis for a bright pixel, thereby forming on-axis light, and away from the optic axis for a dark pixel, thereby forming off-axis light. The separating optics are coupled to the light modulator and separate the off-axis and on-axis light where the on-axis light produces a real and virtual image that is displayed by the projection and scanning optics.

Abstract: The invention relates to a projection display device comprising a illumination system having a light source and an optical bar for providing an illumination beam, an image display system comprising a display panel for modulating the illumination beam with image information and projecting the image on a screen, and a color filter provided on a wheel, rotatably mounted at its hub, for transmitting colored portions of the illumination beam for illuminating the display panel. In order to improve the efficiency of the projection display device, the color filter comprises adjacent spiral-shaped filter portions for simultaneously illuminating portions of the display panel by the colored portions of the illumination beam so that the portions of the display panel are consecutively illuminated by the colored portions of the illumination beam.

Abstract: A display system may include an identifier configured to identify an image display condition associated with the display of an image produced by the display system, an apparatus configured to produce a plurality of differently colored images, and a display device. The images have color characteristics based on image information and the identified display condition. Differently colored images may be directed along associated portions of an optical path. The display device may be coupled to the apparatus and may be configured to display a color image formed of the differently colored images.

Abstract: A display system is configured to produce a color image formed of a plurality of differently colored images and may include at least one light source that directs light along an optical path, and at least one filter having a given optical filter characteristic. The display system may be selectively operable in a first state in which the optical path does not pass through a first filter during production of the plurality of differently colored images to form a color image having a first optical characteristic, and in a second state in which the optical path passes through the first filter during production of the plurality of differently colored images to form a color image having a second optical characteristic different than the first optical characteristic.

Abstract: An optical illumination apparatus has a polarization conversion device for converting light from a light source into light polarized uniformly in a predetermined manner and an optical integrator system for illuminating a display panel with the light polarized in the predetermined manner. The polarization conversion device splits the light from the light source into a first light beam and a second light beam in such a way that the first and second light beams are polarized in different manners, and then converts one of the first and second light beams into light polarized in the identical manner as the other light beam. Moreover, the first and second light beams pass through an identical lens cell of a first lens array of the optical integrator system and are imaged on an identical lens cell of a second lens array of the optical integrator system.

Abstract: A color sequential display operative in one of two alternate modes. The first mode is a color sequential mode in which primary color images are displayed in successive frames while respective background light sources are simultaneously flashed on the display. The second mode is a monochrome mode in which the luminance Y signal is displayed in successive frames along with flashes of background white light.

Abstract: A method of operating a projection system with at least one high intensity discharge lamp (HID lamp), a rotatable color disc with at least three segments of different colors, and an array (DMD) comprising a plurality of individually movable mirrors, wherein the current strength of the electrical operating current supplied to the HID lamp is varied in time such that the light arc of the lamp is stabilized, is to be constructed such that the power and operational life of the HID lamp used are optimized. The current strength of the operating current for the HID lamp is for this purpose varied such that the current strength reaches a maximum when a given segment of the color disc, and preferably exclusively this segment, is present in the radiation path of the light rays used for the projection.

Abstract: A liquid crystal-based light valve system with automatic color correction. The invention includes a light input, a liquid crystal-based spatial light modulator, a light output, a light intensity sensor, and a color controller. The light intensity sensor is located along an optical path between the light input and the light output and is configured to detect the intensity of light illuminating the spatial light modulator. The color controller is electrically connected to the light intensity sensor. The color controller may be configured to modulate the light received at the light input. In addition, the spatial light modulator may include a pixellated electrode and control circuitry electrically connected to the pixellated electrode and the color controller. The invention may alternatively include a first, second, and third liquid crystal-based spatial light modulator, a color separator, and a first, second, and third light intensity sensor.

Abstract: The present invention relates to a display device that includes an illumination source configured to direct light along an optical path, a first color filter having a first number of color regions, and a second color filter having a second number of color regions, the first and second color filters being configured so as to cooperate in sequentially filtering the directed light to display an image.

Abstract: A video projector which can obtain high brightness of a projected image, high color purity and low color shading and which can be downsized and reduce the manufacturing cost is provided. The video projector has: an optical source 1; a color selection scanning device 21 for selectively filter a color of a light from the optical source 1 to generate a light flux having a specific color in synchronism with a supplied video signal; a video displaying device 4 for modulating an intensity of the light flux in synchronism with the video signal pixel by pixel to form a modulated image responsive to the video image; an imaging lens 72 disposed between the color selection scanning device 21 and the video displaying device 4, for imaging an intensity distribution and a color distribution of the light flux outgoing from the color selection scanning device 21 on a surface of the video displaying device 4; and a projecting lens 5 for projecting the modulated image formed by the video displaying device 4.

Abstract: Distortion optics are used to efficiently couple a spiral color wheel and an orthogonal modulator. Light 602 from a light source enters an aperture in a reflective end of a recycling integrator rod 604. The light travels through the rod and exits the end of the rod adjacent a sequential color filter 606, shown as a spiral color wheel. The shape of the light beam 608 exiting the integrator rod 604 is determined by the shape of the exit aperture of the integrating rod 606. The exit aperture of the integrating rod 606 typically is formed by a reflective exit aperture on the exit face. A cross section of the light beam 608 exiting the sequential color filter includes several bands of filtered light, one for each of the filter segments of the color wheel illuminated by the light beam. The curvature of the color bands makes it difficult for a row addressed spatial light modulator to efficiently use the light.

Abstract: A single-panel color image display apparatus includes a plurality of switchable color filters selectively transmitting and/or reflecting a plurality of color light beams. In the single panel color image display apparatus, the plurality of color light beams are radiated in turn at the same pixel of a display device so that true color can be realized in a unit pixel during a period of a single video frame. The single-panel color image display apparatus has physically the same resolution as a conventional projection-type single-panel image display apparatus using a color wheel and has substantially the same light efficiency and resolution as a conventional three-panel color image display apparatus using three display devices.

Abstract: An apparatus is disclosed comprising a lamp which produces a first light which may be a white light; a first light valve, a second light valve, a first color separator, and a first aperture device. The first color separator receives the white light from the lamp, and separates the white light into a first color light and a first residual light. The first aperture device receives the first color light and the first aperture device can be controlled to modify a frequency of the first color light to the first light valve. The second light valve receives at least a portion of the first residual light. The first aperture device could also be controlled to substantially block at least a portion of the first color light.

Abstract: A display includes a light source and a filter positioned to receive light from the light source. An electronically controlled mirror can direct light through the filter in a first mode of operation and not through the filter in a second mode of operation. The display can be utilized in an avionics display system with night vision equipment. The electronically controlled mirror can be a reversible electrochemical mirror (REM).

Abstract: A method for using pulse-width modulation in displays. A series of PWM sequences is established. Each subsequent sequence clears the previous sequence before it, eliminating the need for a separate clearing reset at the end of the previous sequence. This allows for use of spoke bits in color-sequential systems. In non-color sequential systems and rapid color-switching systems it allows the sequence for one frame to flow directly into the sequence for the next frame.

Abstract: There is provided a single panel type video display capable of increasing the luminance of image. A color separator separates light from a light source into light beams in three colors in a band shape to emit the light beams and introduces the band-shaped light beams in the three colors so as to be overlapped with one another in a predetermined region. A lens array wheel has a plurality of functional units each composed of a convex lens of a size corresponding to the predetermined region, circularly passes the plurality of functional units each composed of the convex lens through the predetermined region, and scrolls the band-shaped light beams in the three colors in a state where they are divided among regions on a single liquid crystal display panel. A video signal is fed to the liquid crystal display panel in synchronization with the movement of the plurality of functional units each composed of the convex lens.

Abstract: A method and system of increasing the intensity of secondary colors in sequential color display systems. The method utilizes light during a transition period between two primary color periods to form a secondary color. The light generated during this transition is generally not used since it does not represent a pure primary color, but instead typically starts as light of a first pure primary and ends as light of a second pure primary. A display controller determines which secondary color is needed, and the amount of the secondary color needed, and enables the transition or spoke light to contribute to the image during a time period appropriate to desired secondary color intensity given the intensity and switching characteristics of the light during the transition period. For example, light (210) filtered by a color wheel (200) during the transitional period (212 to 214) between a red (102) and green (106) filter is used to increase the yellow component of the image.

Abstract: An apparatus is disclosed comprising a lamp which produces a first light which may be a white light; a first light valve, a second light valve, and a first aperture device, which may be a first electronically switchable filter. The first aperture device or the first electronically switchable filter function as selectively variable color separators. The first aperture device or the first electronically switchable filter each can be placed in a first state where the first light is separated into a first color light and a first residual light, and a second state where the first light is separated into a second color light and a second residual light. The first light valve receives the first light in the first state and the second light in the second state. The second light valve receives at least a portion of the first residual light in the first state or at least a portion of the second residual light in the second state.

Abstract: The invention is an instrument for sensing the state of polarization (SOP), and for transforming the SOP of a beam of light from an incident continuously-varying arbitrary SOP to a desired exit SOP, using a polarization compensator under feedback control. A polarization sensor uses two or three samples of a beam to sense the Poincare sphere latitude and longitude error in SOP. A polarization controller adjusts the SOP of light, which is then sensed by the polarization sensor, which develops signals to drive the polarization compensator using feedback methods. Unlike prior-art systems, the feedback seeks a mid-point rather than an extremum in the sensed signals, so there is no sign ambiguity in the feedback control. Further, the sensor signals indicate orthogonal displacements in SOP that correspond to specific elements in the polarization controller, so there is no ambiguity as to which element needs adjustment in order to correct a given error in SOP.

Abstract: In a projection display that includes a polarization beam splitter prism and two reflective light valves, each of a pair of dichroic beam splitters is disposed between the polarization beam splitter prism and a respective one of the reflective light valves. The arrangement as such ensures that only a minimal amount of light leakage components will reach a projection lens of the projection display so as to achieve optimum image quality.

Abstract: Light is shined on an addressable spatial light modulator, and the light is also integrated. The data displayed on the spatial light modulator is changed when the integrated light reaches a predetermined value. The light may impinge on the spatial light modulator through a color wheel, which may be rotated faster than the frame repetition rate of video information that is being displayed. Alternatively, the light may be generated by different-colored lamps. The intensity of the light may be controlled in accordance with the bit rank or significance of the bits that are being displayed by the spatial light modulator. Several techniques for achieving different intensity levels are disclosed.

Abstract: In an image display apparatus having a light source having a plurality of light emitting devices, and making lights from the light source scan in a main scanning direction and in a subscanning direction to display on a screen an image having a predetermined number of pixels, scanning lines in the main scanning direction formed by the lights emitted from each of the light emitting devices are controlled to be superposed one on another on the screen. The plurality of light emitting devices in the light source may be separated into a certain number of light emitting device groups respectively outputting lights with which different image areas on the screen are irradiated. The light emitting device groups may be arranged in a direction corresponding to subscanning or in a direction corresponding to main scanning while being spaced apart from each other by a distance determined on the basis of a pixel pitch in the main scanning direction or the subscanning direction.

Abstract: A color liquid crystal projector has an optical system for color splitting. The optical system includes a mirror for reflecting a first primary-color light and transmitting second and third primary-color lights in light from a light source; a first phase plate for transmitting the second primary-color light from the mirror with its polarization degree rotated through 90°, and for transmitting the third primary-color light; a first prism for transmitting the second primary-color light from the first phase plate into a second liquid crystal display panel, and reflecting the third primary-color light from the first phase plate into a third liquid crystal display panel; a second prism for entering the first primary-color light from the mirror into a first liquid crystal display panel; and a dichroic prism for combining the first, second and third primary-color lights reflected from the liquid crystal display panels.

Abstract: A method and display system for using the light (110) passing through the spokes of a color wheel (100). The light is a mixed and rapidly changing color. Adding all of the spoke times produces white, but adding a subset creates color artifacts. The spoke times cannot all be added at the same time without altering the white point of the display. The spoke times are added in a sequence and the sequence is altered over time for the same pixel such that the pixel converges to white over time. The pattern of spoke bits is arranged so that as adjacent spoke bit pixels are added, the net spoke light converges to white. The patterns are also varied so that as more and more spoke bit periods are turned on, the net spoke light converges to white. Each spoke bit period adds n-LSBs of white light intensity, so as each spoke bit period is added, n−I LSBs of white light are subtracted from the white data.

Abstract: A field sequential dichroic light valve using ferro-electric liquid crystal components and multi-layer thin film broadband polarizing beam-splitting devices as an optical switch. The field sequential dichroic light valve has a fast time response and a memory function, as well as a switch frequency larger than 180 Hz and an optical transmittance larger than 90%. Accordingly, the field sequential dichroic light valve can effectively switch R, G, B-colored light beams in time sequence, and can be applied to a full-color projection display system.

Abstract: The present invention provides a high brightness color selective light modulator (CSLM) formed by a polarization modulator positioned between two retarder stacks. The modulator changes the apparent orientation of one retarder stack relative to the other so that, in a first switching state of the modulator the two retarder stacks cooperate in filtering the spectrum of input light, and in a second switching state the two retarder stacks complement each other, yielding a neutral transmission spectrum. Two or more CSLM stages can be used in series, each stage providing independent control of a primary color. One preferred embodiment eliminates internal polarizers between CSLM stages, thereby providing an additive common-path full-color display with only two neutral polarizers. Hybrid filters can be made using the CSLMs of this invention, in combination with other active or passive filters.

Abstract: A sequential color display system using three spatial light modulators and dichroic filters to sequentially provide a primary color light beam to a projection spatial light modulator. A set of dichroic filters separates a white light beam into primary colored light beams. Each primary colored light beam is modulated by a spatial light modulator to selectively allow it to travel to a second set of dichroic filters. The second set of dichroic filters recombines the primary color light beams—only one of which is typically active at any given time—to form a sequential color light beam. A projection spatial light modulator selectively modulates the sequential color light beam to form a sequential color image projected onto an image plane.

Abstract: A field sequential color projection display system, which has high brightness, high accuracy and compact size, and is light and energy saving. The field sequential color projection system comprises: a field sequential beam splitting/combining light valve module including three light valves, which can be controlled by applied energy field, for outputting polarized light of three primary colors in time sequence; a frame sequential display module for respectively displaying frames of three primary colors corresponding to the polarized light of three primary colors output in time sequence, wherein the polarized light passes through the frame sequential display module; a projection lens module for projecting the polarized light passing through the frame sequential display module onto a screen to produce a full color image.

Abstract: A display system using red, green, blue, and white light. The system derives data for the white portion of a color wheel or a white device from the red, green and blue data. The white portion of the color wheel is controlled as if it were another primary color on the wheel. Errors are prevented by a correction applied if the unfiltered light from the source has a different color temperature than the white light produced using the red, green and blue segments of the color wheel, or the devices for those colors. Analysis is performed on the data to determine if white light is necessary to be added to each frame of data.

Abstract: Methods and apparatus for producing a pulse-width-modulated (PWM) grayscale or color image using a binary spatial light modulator. By staggering and re-quantizing the PWM intervals to a clock of a period based on the frame time divided by number of rows in the display, the system's peak bandwidth requirements are optimized for displays of arbitrary resolution and arbitrary choice of PWM waveform. Additionally, a gating circuit increases the optical efficiency of a spatial light modulator using this PWM method in a field-sequential color system by reducing the duration of the blanking period between color fields.

Abstract: A dichroic spiral color wheel (108) having many spiral-shaped color filters (206). The boundary between adjacent color filters follows the spiral of Archimedes, defined as r=a&thgr;, where r is the radius of the boundary at a given point, a is a constant, and &thgr; is the angle between a radial line through the given point and a reference radial. Using the spiral of Archimedes provides a boundary between adjacent color filters that is nearly parallel to the rows or columns of the modulator and moves across the light path at a constant speed. These two features make the spiral color wheel much more efficient than color wheels having pie shaped segments. The use of dichroic filters, which reflect out of band light is crucial to the operation of a sequential color recycling display system.

Abstract: A picture display method and apparatus in which a light source is lengthened in service life and optimum color reproduction is realized, while the light utilization efficiency is improved to reduce the power consumption and the size of the apparatus. The red, green and blue illuminating light beams radiated from the light-emitting diodes 12R, 12G and 12R, are illuminated via relay lenses and field lenses on picture display light valves 11R, 11G and 11B and spatially modulated in intensity so as to be synthesized by a synthesis prism 10 and so as to be projected to an enlarged scale on a screen 17. The profile of the light radiating portions of the light-emitting diodes 12R, 12G and 12B are set so as to be the same or similar to the profile of a picture display area of each of the picture display light valves 11R, 11G and 11B in order that the profile of the light beam illuminated on the picture display area will be in keeping with the profile of the picture display area.