JP2006003636A - Illumination optical system and projection display device using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination system and a projection display device capable of efficiently using the light from the light source and obtaining bright projection display images. <P>SOLUTION: This is an illumination system to convert the light from the light source into linearly-polarized light, and to form a striped image through a linear cylindrical lens array, then to project this striped image through a focusing lens on an object to illuminate. It has a multi-layered wavelength band spatial separating means consisting of color polarizers and birefringent elements within the light path to project the above striped images on the object, and projects the multi-color striped images separated in many colors to illuminate the object. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device. In particular, the present invention relates to a display device that illuminates a spatial light modulator with emitted light from a light source, modulates and generates an image pattern by the spatial light modulator, and projects the modulated image pattern image onto a projection target, that is, a projector display device It is.

  Conventional projector-type displays such as those described in Patent Documents 1 to 5 usually use a liquid crystal panel or a micromirror array device panel as a light modulation panel for switching, and control light transmission and blocking or deflection. By projecting the selected light pattern onto the screen, an image is displayed on the screen.

  In a projector using a liquid crystal panel or a micromirror array device panel as a light modulation panel, it is important to use light source light with high efficiency and to reduce illuminance unevenness on the screen.

  As an improvement means, there is known an optical integrator composed of two two-dimensionally arranged lens arrays and a condenser lens. The integrator divides a light beam from a light source into a plurality of light beams by a first lens array. The second lens array and the condenser lens are used to superimpose these light beams on the display area of the liquid crystal panel while enlarging them.

  In this method, a light beam with small uneven illuminance unevenness is superimposed, so that highly uniform irradiation light can be obtained, and the uneven illuminance on the screen is greatly improved. Further, if each aperture of the first lens array has a shape similar to the display area of the light modulation panel, the luminous flux after the division is irradiated to the display area, so that the efficiency of the irradiation light is improved and the light source light utilization efficiency is improved. Can be improved.

  As another improvement means, the light source light is guided to the kaleidoscope, and the light vector is mixed to make the light intensity distribution on the light emitting end face of the kaleidoscope uniform, and this image is obtained. Some imaging lenses form an optical conjugate image on a light modulation panel.

  Also in this method, highly uniform irradiation light can be obtained, and illuminance unevenness on the screen can be greatly improved.

Japanese Patent Laid-Open No. 06-091923 JP 2000-321529 A JP 2001-228533 A JP 2002-057964 A JP 2002-139797 A

  However, although it is effective for uniform distribution of illumination light, a full-color image is displayed regardless of whether the spatial light modulator is a transmissive or reflective liquid crystal modulation element or micromirror array modulation panel. In the case of modulation with three spatial light modulators corresponding to the three primary colors of light, the amount of radiated light from the light source is caused by the loss of light transfer efficiency generated by the wavelength band separation and combining means corresponding to the three primary colors. The utilization efficiency of will decrease. In addition, when the three primary colors are temporally displacement-modulated and illuminated on a single-plate modulation panel using the method realized in the case of the micromirror array modulation panel, the color is temporally and spatially modulated and illuminated. Since it is a system that absorbs or reflects light other than the wavelength band of the necessary color, the use efficiency of the amount of radiated light from the light source is similarly reduced.

  In other words, conventionally, the system has not been a system that can effectively use the radiated light from the light source for light modulation statically or dynamically.

  In order to achieve the above object, the present invention provides an illumination optical system configured as in the following (1) to (16) and a projection display device using the illumination optical system.

  (1) An illumination system that converts light from a light source into linearly polarized light, forms a striped light image via a one-dimensional cylindrical lens array, and projects and illuminates the striped light image onto an object to be illuminated by an imaging lens In the optical path for projecting the stripe light image onto the object to be illuminated, wavelength band space separation means comprising a multilayer structure of a color polarizer and a birefringent element is provided, and a multicolor stripe separated into a plurality of colors An illumination optical system for illuminating an object to be illuminated with a light image.

  (2) For the light in the linear polarization state, non-polarized light that does not have polarized light polarized at the light source is used, the non-polarized light is converted into a multi-stage polarization beam splitter, and one polarized wave is converted to the other polarized wave 1 / The illumination optical system according to (1), wherein the illumination optical system is generated using a unit called a PS conversion element including a combination of 2λ wavelength plates.

  (3) The illumination optical system according to (1), wherein the multicolor stripe light image is a multistage stripe light image of the three primary colors of light and is a repeating periodic image of three color bands.

  (4) The wavelength band space separation means comprising a multilayer structure of a color polarizer and a birefringent element comprises, in order from the light incident side, the color polarizer A, the birefringent element A, the color polarizer B, the birefringent element B, and the color polarized light. The color polarizer A, the color polarizer B, and the color polarizer C are elements that provide a cross polarization conversion function for only one of the three primary colors red, green, and blue. The illumination optical system according to (1), wherein the color polarizer A, the color polarizer B, and the color polarizer C are configured to give a cross polarization conversion action to different colors.

  (5) The illumination optical system according to (1), wherein the birefringent element is made of a plate whose crystal optical axis of lithium niobate or quartz is inclined by about 45 degrees with respect to the light incident surface.

  (6) The illumination optical system according to (1), wherein the color polarizer has a multilayer laminated structure of refractive index ellipsoidal films in which optical axes are inclined in a predetermined direction in each layer called retardation stacks.

  (7) The optical band width of the striped light image generated by the one-dimensional cylindrical lens array and the shift pitch between the colors separated by the wavelength band space separation means composed of the multilayer structure of the color polarizer and the birefringent element are substantially the same. The illumination optical system according to (1), wherein the illumination optical system is configured with a width.

  (8) The illumination optical system according to (1), wherein the light source is a short arc discharge lamp.

  (9) The illumination optical system according to any one of claims 1 to 8 is used as the illumination optical system to illuminate a spatial light modulation element in which light modulation pixels are arranged in a two-dimensional manner, thereby becoming illumination light. The color stripe light image is displaced by a temporal displacement means, and each pixel of the spatial light modulator is modulated in synchronization with the input image signal and the illuminated color, and the output light having the modulated image information is A projection display device, wherein an image is displayed by being projected onto an object by a projection lens.

  (10) The means for temporally displacing the multicolor stripe light image as the illumination light on the surface of the spatial light modulator is a mechanical actuator that controls the displacement of the one-dimensional cylindrical lens array incorporated in the illumination optical system. The projection display device according to (9), characterized in that:

  (11) A means for temporally displacing a multicolor stripe light image serving as illumination light on the surface of the spatial light modulation element is a refractive index modulation of a Pockels element or the like between the one-dimensional cylindrical lens array of the illumination optical system and the spatial light modulation element. The projection display device according to (9), wherein an element is arranged to perform parallel movement control of the light beam.

  (12) From the above (9), the spatial light modulator is a spatial light modulator that modulates the intensity of light to be projected by a combination of light polarization state modulation and a light detecting element such as a liquid crystal light valve element. (11) The projection display device according to (11).

  (13) The projection display device according to (12), wherein the liquid crystal light valve element is a ferroelectric liquid crystal modulation element using a ferroelectric liquid crystal.

  (14) The projection display device according to (12), wherein the liquid crystal light valve element is an antiferroelectric liquid crystal modulation element having an antiferroelectric liquid crystal phase state.

  (15) The projection display apparatus according to any one of (9) to (14) above, wherein the projected image is projected on a screen and can be recognized by diffuse reflected light having a predetermined directivity.

  (16) The projection display device according to any one of (9) to (14) above, wherein the projected image is projected on a screen and can be recognized by diffused transmitted light having a predetermined directivity.

  According to the invention of the present application, it solves problems such as loss of light amount transfer during color separation / combination and a decrease in utilization efficiency of the amount of radiated light from the light source, and a remarkably bright projected display image with high utilization efficiency of the light source light. It is possible to provide a projection display device that can obtain the above.

  The illumination optical system and projection display device of the present invention will be described below with reference to the drawings.

(First embodiment)
An embodiment of a first projection display device according to an embodiment in which an illumination device (illumination optical system) of the present invention is arranged will be described with reference to FIGS. FIG. 1 to FIG. 3 are main part schematic perspective views of main optical units constituting the embodiment of the first projection display device as seen from different directions.

  4 is a gas-excited emission source with a parabolic reflection mirror, which is a light source, and generates a substantially parallel visible light beam in combination with a parabolic reflection mirror. The resulting collimated beam is a high quality collimator with as little divergence (divergence angle) as possible In order to produce a luminous flux, the discharge gap is designed to be as narrow as possible so as to limit the electron excitation region of the gas, and the light source is close to point light source emission.

  Furthermore, in order to obtain a light emitting source that is closer to a point light source, instead of applying an AC bias to the discharge gap and emitting electrons from both sides of the electrode to form a two point point light source, the luminous efficiency and energy conversion efficiency are improved. In some cases, a high-brightness point light source may be generated on the cathode electrode side by applying a DC bias.

  Next, ultraviolet rays outside the visible light region of the light flux emitted from the gas excitation light source 4 with the parabolic reflection mirror are absorbed or reflected by the ultraviolet cut filter 5. In the long term, ultraviolet rays can also excite or degrade the optical glass or optical thin film that is the material of the lens, but when using liquid crystal elements in light modulation panels, liquid crystal polymers that are organic materials are The main purpose is to prevent this.

  Next, the visible light beam that has passed through the ultraviolet cut filter 5 is incident on the first cylindrical array homogenizer 6. The first cylindrical array homogenizer 6 has refracting power only in the vertical direction in the figure, and divides the incident light flux into the number of the array, individually connects the focal lines, and then is again predetermined by the cylindrical condenser lens 12. It is converted into a parallel light beam set to a width.

  Here, the main plane distance between the first cylindrical array homogenizer 6 and the cylindrical condenser lens 12 is set to the sum of the focal length of the first cylindrical array homogenizer 6 and the focal length of the cylindrical condenser lens 12. Thereby, the light flux is reconverted into a parallel light flux as described above.

  Further, since the optical axis of the first cylindrical array homogenizer 6 is decentered with respect to the optical axis of each array, the cylindrical condenser lens 12 has each of the first cylindrical array homogenizer 6 at the position of the focal line of the cylindrical condenser lens 12. Superimpose the light beams that have passed through the array. Thereby, an optical integration operation is performed. The position of the focal line of the cylindrical condenser lens 12 becomes the modulation surface of the light modulation panel 1.

  The light beam that has passed through the first cylindrical array homogenizer 6 passes through the second cylindrical array homogenizer 7. The position of the focal line of the second cylindrical array homogenizer 7 is set to the pupil position of each array of the first cylindrical array homogenizer 6, and the second cylindrical array homogenizer 7 and the cylindrical condenser lens 12 have a tandem lens configuration. The pupil of each array of the 1 cylindrical array homogenizer 6 and the modulation surface of the light modulation panel 1 are optically conjugate. For this reason, the pupils of the respective arrays of the first cylindrical array homogenizer 6 are imaged on the modulation surface of the light modulation panel 1 in the vertical direction in the figure.

  The light beam emitted from the gas excitation light source 4 does not become completely parallel light but has divergence. Therefore, the second cylindrical array homogenizer 7 reliably guides the light beams that have passed through the pupils of the respective arrays of the first cylindrical array homogenizer 6 to the modulation surface of the light modulation panel 1 in order to correct the divergence of the divergence. .

  The light beam that has passed through the second cylindrical array homogenizer 7 enters the polarization conversion element array 8. The polarization conversion element array 8 is similar to what is generally called a PS conversion element used in a liquid crystal projector, and is an array in which light emitted from a lamp unit is superimposed on a polarization beam splitter. It converts only to a polarized light component parallel to the horizontal direction. That is, the polarization component in the vertical direction in the figure passes through the polarization separation film, and the polarization direction is changed by 90 degrees with a half-wave retardation plate (not shown) immediately before exiting the polarization conversion element array, and the horizontal direction in the figure. Output as linearly polarized light in the direction. The horizontal polarization component in the figure reflected by the polarization separation film is reflected again by the polarization separation film of the adjacent polarization beam splitter array, and the optical path is shifted by the array pitch and emitted. In this way, all the light beams that have passed through the polarization conversion element array 8 become horizontal linearly polarized light in the drawing.

  The light beam that has passed through the polarization conversion element array 8 is incident on the first cylindrical lens 9 via the cylindrical lens array 3 and the wavelength band space separation means 2. The functions of the cylindrical lens array 3 and the wavelength band space separating means 2 will be described later. The first cylindrical lens 9 has a refractive power only in the horizontal direction in the figure, and is composed of two second aspherical cylindrical lenses 10 and a third aspherical cylindrical lens 11 that are disposed in the traveling direction of the light beam. A beam compressor is formed by the combination. Therefore, the light beam incident on the first cylindrical lens 9 is compressed in the horizontal direction in the drawing and guided to the light modulation panel 1.

  The light beam that has passed through the first cylindrical lens 9 is incident on the cylindrical condenser lens 12, and is reflected by the cylindrical condenser lens 12 on the modulation surface of the light modulation panel 1 at the focal line position of the cylindrical condenser lens 12 as described above. Are superimposed and integrated in the vertical direction.

  The light beam that has passed through the cylindrical condenser lens 12 is incident on the second aspherical cylindrical lens 10 and the third aspherical cylindrical lens 11. As described above, the second aspherical cylindrical lens 10 and the third aspherical cylindrical lens 11 have refractive power only in the horizontal direction in the figure, and form a beam compressor paired with the first cylindrical lens 9. ing. Thereby, the light beam is compressed in the horizontal direction in the figure, and the light beam is guided to the light modulation panel 1 in an afocal state.

  Further, the second aspherical cylindrical lens 10 and the third aspherical cylindrical lens 11 form and project the focal line image of the cylindrical lens array 3 onto the modulation surface of the light modulation panel 1.

  Similar to the role of the second cylindrical array homogenizer 7, the second aspherical cylindrical lens 10 and the third aspherical cylindrical lens 11 increase the luminous flux divergence corresponding to the divergence of the luminous flux emitted from the gas excitation light source 4 with the parabolic reflection mirror. The light beam that has been corrected and passed through the pupil of the first cylindrical lens 9 is arranged to reliably guide the light to the modulation surface of the light modulation panel 1.

  The light beam that has passed through the third aspherical cylindrical lens 11 enters the polarization beam splitter 13 and is polarized in the vertical direction in the drawing by the liquid crystal light modulation panel 1 using the polarization separation film of the polarization beam splitter 13. The light whose state has been modulated according to the image drive signal of the light modulation panel driver 16 and whose polarization direction has been converted passes through the polarization separation film of the polarization beam splitter 13 and is guided to the projection lens 14. The modulation plane information is imaged and projected onto the light diffusion screen 15 to display an image.

  On the other hand, after passing through the polarization conversion element array 8, the behavior of the light beam in the cylindrical lens array 3 and the wavelength band space separation means 2 is divided into regions by the respective cylindrical surfaces of the cylindrical lens array 3 arranged in the horizontal direction in the figure. Then, each cylindrical surface receives a lens action to form a focal line array. However, since the incident light beam has divergence, each focal line is not a thin line, and a stripe pattern having a predetermined width is formed. The stripe pattern is color-separated by the wavelength band space separating means 2, and then the arrangement direction of the cylindrical lens array 3 is directed to the light modulation surface of the liquid crystal light modulation panel 1 by the second aspherical cylindrical lens 10 and the third aspherical cylindrical lens 11. Projection imaging transfer is performed, and the color separation method by the wavelength band space separation means 2 will be described in detail later.

  The light modulated by the pixel polarization modulation drive of the liquid crystal light modulation panel 1 has a polarization direction that is 90 degrees different from the polarization direction of the incident light because the light reflected by the ON output pixel is subjected to phase difference modulation with linear polarization of π. And is transmitted to the projection lens 14 through the polarization separation film of the polarization beam splitter 13, and the light reflected light from the OFF output pixel preserves the linear polarization direction and is reflected by the polarization separation film of the polarization beam splitter 13. By returning to the light source side, light modulation of image information is performed.

  Next, the light of the ON output pixels captured by the projection lens 14 is imaged and projected on the light diffusion screen 15 to display a light modulation pattern.

  On the other hand, as a flow of a modulation signal for driving the liquid crystal light modulation panel 1, a drive signal from the light modulation panel driver 16 that converts an external video input signal (not shown) into a light modulation panel drive signal is shown through a solid line in the figure. The liquid crystal light modulation panel 1 is controlled.

  Further, as the projection display device, the screen 15 may be a reflection type or a transmission type, and if a screen having a predetermined diffusivity is used, it functions as a display device that recognizes an image by directly viewing the screen 15. Is.

  Next, a color separation method by the wavelength band space separation means 2 will be described with reference to FIG.

  FIG. 5 is a diagram illustrating the color separation method by the wavelength band space separation means 2, and the optical path of only the central ray of each light beam divided by the cylindrical lens array 3 is an ordinary ray and an extraordinary ray, and the divided wavelength band center ray. Show. Since the actual light flux has a convergence and divergence angle, the separated light fluxes overlap each other, but the color separation is generated by the cylindrical lens array 3 because it is separated by parallel shift due to ordinary light and abnormal light due to the polarization component of the light. A striped optical image plane is projected and transferred by a second aspherical cylindrical lens and a third aspherical cylindrical lens indicated by 10 and 11 in FIGS. 1 to 3 (not shown), and a color-separated stripe image is transferred. Can do.

  Each part and function shown in FIG. 5 will be described in detail.

  White natural light linearly polarized in the vertical direction in FIG. 5 is incident on the cylindrical lens array 3 from the direction indicated by the leftmost arrow in the figure, and the incident light is gas-excited with a parabolic reflecting mirror (not shown). A substantially parallel beam having divergence from the light source 4 is incident. The cylindrical lens array 3 applies an refracting power to the incident light beam in the vertical direction of the paper surface in each cylindrical surface region to generate an arrayed convergent light beam. The generated arrayed convergent light beam forms a stripe light image having the minimum width near the focal line position of the cylindrical lens, and then proceeds as divergent light so that the respective light beams overlap. The color is spatially separated using the polarization component and the wavelength component with respect to the progress of the light, but the light incident on the wavelength band space separation means 2 from the cylindrical lens 3 is converted into the wavelength band space separation means 2. The central ray of each light beam is perpendicularly incident on the blue cross phase difference imparting color polarizer 2PA, which is one of the constituent elements. Incident light is given a phase difference of π, that is, retardation, to the electric field vector and magnetic field vector of the electromagnetic wave only in the blue wavelength band, as a result, the linearly polarized component only in the blue wavelength band undergoes cross orthogonal transformation, The linearly polarized light in the vertical direction in the blue color is converted into the linearly polarized light in the vertical direction in the figure. The other yellow color components are output without being affected by linearly polarized light in the vertical direction in the figure.

  Next, the negative refractive index ellipsoidal crystal birefringent element A is incident on 2SA of the negative refractive index ellipsoidal crystal birefringent element A. The negative refractive index ellipsoidal crystal birefringent element A is made of a single crystal of lithium niobate and the crystal optical axis is relative to the light incident surface. As shown in the direction of the thick solid arrow in the figure, it is inclined about 45 degrees. The single crystal of lithium niobate is a negative uniaxial refractive index ellipsoidal crystal, and acts as an ordinary ray for the polarization component in the direction perpendicular to the crystal optical axis d due to the ordinary refractive index and the extraordinary refractive index. A Savart plate acting as an extraordinary ray is formed for a component parallel to the crystal optical axis d.

  The optical axis of the incident natural light is decomposed into the polarization direction of the electromagnetic wave, and the polarized wave having the component perpendicular to the crystal optical axis (the polarization direction wave of the mark in the figure) goes straight as normal light and is parallel to the crystal optical axis. A polarized wave having a large component (a polarization direction wave indicated by a vertical arrow in the figure) is bent in the traveling direction as an extraordinary ray and travels downward in FIG. When ordinary light and extraordinary light are separated by an amount depending on the plate thickness L1 of the Savart plate, and the 2SA of the negative refractive index ellipsoidal crystal birefringent element A that is a Savart plate is emitted, the light vector is a negative refractive index ellipsoidal crystal. The vector incident on 2SA of the birefringent element A is stored and emitted.

  Therefore, a blue light beam linearly polarized in the direction perpendicular to the paper surface in the drawing, that is, a blue ordinary ray generated by the action of the blue cross phase difference imparting color polarizer 2PA, travels as it is without being shifted in the traveling direction, A yellow light beam linearly polarized in the vertical direction in the drawing, that is, an extraordinary ray of yellow color, is shifted downward by a pitch P indicated by P in the drawing and is emitted.

  Next, the light that has undergone one-step light beam separation by the 2SA of the negative refractive index ellipsoidal crystal birefringent element A, which is a Savart plate, enters the green cross phase difference imparting color polarizer 2PB perpendicularly to the central ray of each light beam. Incident light is given a phase difference of π, that is, retardation, to the electric field vector and magnetic field vector of the electromagnetic wave only in the green wavelength band, and as a result, the linearly polarized component only in the green wavelength band undergoes cross orthogonal transformation, Green extraordinary rays are converted to ordinary rays, and the other blue and red components are emitted without any action.

  Next, the light enters the 2SB of the negative refractive index ellipsoidal crystal birefringent element B, which is also a Savart plate. The incident light has the ordinary blue color, the ordinary light green color and the extraordinary red color at positions different by the pitch P. Similarly to the negative refractive index ellipsoidal crystal birefringent element A, the negative refractive index ellipsoidal crystal birefringent element B is made of a single crystal of lithium niobate and the crystal optical axis is a solid solid arrow in the figure with respect to the light incident surface. As shown in the direction, it tilts about 45 degrees. It forms a Savart plate that acts as an ordinary ray for a polarized component perpendicular to the crystal optical axis d and acts as an extraordinary ray for a component parallel to the crystal optical axis d. In the incident light, the polarization of the component perpendicular to the crystal optical axis goes straight as an ordinary ray, and the polarization having a component parallel to the crystal optical axis is bent in the traveling direction as an extraordinary ray. Proceeds in the middle down direction. The plate thickness L2 of the negative refractive index ellipsoidal crystal birefringent element B acting as a Savart plate is set to the same thickness as the plate thickness L1 of the negative refractive index ellipsoidal crystal birefringent element A, and depends on the plate thickness L2. When the ordinary light and the extraordinary light are separated by the amount, and the 2SA of the negative refractive index ellipsoidal crystal birefringent element B which is a Savart plate is emitted, the light vector is incident on the 2SA of the negative refractive index ellipsoidal crystal birefringent element B. The vector is stored and emitted. That is, only the red color of the extraordinary ray travels downward in FIG. 5 and is designed to shift by the same amount as the light beam shift amount by the negative refractive index ellipsoidal crystal birefringence element A which is a Savart plate. Therefore, the emitted light beam is incident on the wavelength band space separating means 2 and is not subjected to any shift displacement, and the blue ordinary ray is subjected to the downward shift displacement by the pitch P indicated by P in the figure. The light is separated into red extraordinary rays that have been shifted downward by twice the pitch P and emitted.

  Next, the central light beam of each light beam enters the red cross phase difference imparting color polarizer 2PC vertically. The incident light is given a π retardation only in the red wavelength band, and as a result, the linearly polarized light component only in the red wavelength band undergoes cross orthogonal transformation, and the red extraordinary ray is converted into an ordinary ray, The other blue and green color components are emitted without any action. Due to the action of the red cross phase difference imparting color polarizer 2PC, all the emitted light beams are linearly polarized light in the direction perpendicular to the paper surface in FIG. 5, that is, the blue color light that is incident on the wavelength band space separation means 2 and receives no shift displacement. The light is separated into an ordinary ray, a green ordinary ray that has been shifted down by the pitch P indicated by P in the figure, and a red ordinary ray that has been shifted down by the pitch P twice as much.

  Furthermore, by providing a polarizer 2R that allows only a linearly polarized light beam in the direction perpendicular to the paper surface in the figure to pass and absorbs an elliptically polarized light component and a vertically polarized light component in the figure on the light beam emission side of the wavelength band space separating means 2, Unnecessary polarization components due to the action error of the color polarizer and the action error of each Savart plate can be removed, and a color separation stripe image with high color purity can be formed.

  On the other hand, since the light beam finally emitted from the wavelength band space separating means 2 is designed so that the pitch of the cylindrical lens array is three times the pitch P, the color-separated stripe images are blue, green and red. A repetitively equidistant image at the pitch P is formed.

  Accordingly, the luminous flux emitted from the wavelength band space separation means 2 is generated as a repeated luminous flux having a pattern of the ordinary light blue luminous flux 100B, the ordinary light green luminous flux 100G, and the ordinary light red luminous flux 100R.

  Next, the generated parallel pitch shift color-separated light fluxes are generated, so that the focal line focusing stripe pattern of the cylindrical lens array 3 described above is converted by the second aspherical cylindrical lens 10 and the third aspherical cylindrical lens 11. A color separation stripe pattern is projected and transferred to the liquid crystal light modulation panel 1, and the cylindrical lens array 3 is reciprocally shifted by an actuator such as a linear ultrasonic motor (not shown) in the arrow direction indicated by S in FIG. The color separation stripe illumination image on the light modulation surface 1E of the light modulation panel 1 moves.

  The moving operation will be described with reference to FIG.

  The color separation stripe illumination image is reciprocally shifted in synchronization with the movement of the cylindrical lens array 3 in the arrow direction indicated by S in FIG. The reciprocating stroke moves according to the length of the cylindrical lens array 3 and repeats the reciprocating motion.

  Further, the image projected and displayed on the screen 15 is temporally modulated by modulating each pixel of the liquid crystal light modulation panel 1 corresponding to the color in synchronization with the color illuminated on each pixel of the liquid crystal light modulation panel 1. A full color image is displayed by mixing colors. However, in the case of modulating a color signal, modulation and temporal color mixing are performed at an early time based on ergonomics in which human visual reaction cannot catch up.

  Since the operation follow-up time of TN liquid crystal, which is generally used at present, is as slow as 5 to 20 milliseconds because of the modulation rewriting speed of the liquid crystal light modulation panel, in this embodiment, the liquid crystal light modulation panel includes a ferroelectric liquid crystal device. Or, an antiferroelectric liquid crystal device is used. In addition, a liquid crystal device having a operability using a liquid crystal molecular material having a large Δε value which is a dielectric anisotropy parameter and faster than 1 millisecond can be used.

  When the cylindrical lens array 3 is not operated, a refractive index modulation element such as a Pockels element or an optical Kerr effect element is arranged between the cylindrical lens array 3 of the illumination device and the liquid crystal light modulation panel 1 so that the Pockels element is provided. The parallel movement control of the light beam may be performed by controlling the applied electric field intensity.

(Second Embodiment)
An embodiment of a second projection display device according to an embodiment in which the illumination device of the present invention is arranged will be described with reference to FIG. FIG. 4 is a schematic perspective view of a main part of a main optical unit constituting the embodiment of the second projection display device.

  Reference numeral 24 denotes a gas excitation light source with a parabolic reflection mirror as a light source, which generates a substantially parallel visible light beam in combination with a parabolic reflection mirror. The resulting collimated beam has a high quality collimation with as little divergence (divergence angle) as possible. In order to produce a luminous flux, the discharge gap is designed to be as narrow as possible so as to limit the electron excitation region of the gas, and the light source is close to point light source emission.

  Furthermore, in order to obtain a light emitting source that is closer to a point light source, instead of applying an AC bias to the discharge gap and emitting electrons from both sides of the electrode to form a two point point light source, the luminous efficiency and energy conversion efficiency are improved. In some cases, a high-brightness point light source may be generated on the cathode electrode side by applying a DC bias.

  Next, ultraviolet rays outside the visible light region of the light flux emitted from the gas excitation light source 24 with the parabolic reflection mirror are absorbed or reflected by the ultraviolet cut filter 25. In the long term, ultraviolet rays can also excite or degrade the optical glass or optical thin film that is the material of the lens, but when using liquid crystal elements in light modulation panels, liquid crystal polymers that are organic materials are The main purpose is to prevent this.

  Next, the visible light beam that has passed through the ultraviolet cut filter 25 is incident on the first cylindrical array homogenizer 26. The first cylindrical array homogenizer 26 has refracting power only in the vertical direction in the figure, and divides the incident light flux into the number of the array and individually connects the focal lines, and then is again predetermined by the cylindrical condenser lens 32. It is converted into a parallel light beam set to a width.

  Here, the main plane distance between the first cylindrical array homogenizer 26 and the cylindrical condenser lens 32 is set to the sum of the focal length of the first cylindrical array homogenizer 26 and the focal length of the cylindrical condenser lens 32. Thereby, the light flux is reconverted into a parallel light flux as described above.

  Further, since the optical axis of the first cylindrical array homogenizer 26 is decentered with respect to the optical axis of each array, the cylindrical condenser lens 32 has each of the first cylindrical array homogenizer 26 at the position of the focal line of the cylindrical condenser lens 32. Superimpose the light beams that have passed through the array. Thereby, an optical integration operation is performed. The position of the focal line of the cylindrical condenser lens 32 is projected and transferred at the same magnification by the concave mirror 33 and the convex mirror 34 constituting the mirror projection system, and becomes the modulation surface of the liquid crystal modulation panel 21.

  The light beam that has passed through the first cylindrical array homogenizer 26 passes through the second cylindrical array homogenizer 27. The position of the focal line of the second cylindrical array homogenizer 27 is set to the pupil position of each array of the first cylindrical array homogenizer 26. With the tandem lens configuration of the second cylindrical array homogenizer 27 and the cylindrical condenser lens 32, The pupil of each array of the 1 cylindrical array homogenizer 26 and the modulation surface of the light modulation panel 21 are projected and transferred at the same magnification by the concave mirror 33 and the convex mirror 34 constituting the mirror projection system, and are optically conjugate. ing. Therefore, the pupils of the respective arrays of the first cylindrical array homogenizer 26 are imaged on the modulation surface of the light modulation panel 21 in the vertical direction in the drawing.

  The light beam emitted from the gas excitation light-emitting source 24 does not become completely parallel light but has divergence. For this reason, the second cylindrical array homogenizer 27 corrects the beam spread corresponding to the divergence by using the concave mirror 33 and the convex mirror 34 that constitute the mirror projection system using the light beams that have passed through the pupils of the respective arrays of the first cylindrical array homogenizer 26. The light is reliably guided to the modulation surface of the light modulation panel 21 via

  The light beam that has passed through the second cylindrical array homogenizer 27 enters the polarization conversion element array 28. The polarization conversion element array 28 is similar to what is generally called a PS conversion element used in a liquid crystal projector, and is an array in which light emitted from a lamp unit is superimposed on a polarization beam splitter. It converts only to a polarized light component parallel to the horizontal direction. That is, the polarization component in the vertical direction in the figure passes through the polarization separation film, and the polarization direction is changed by 90 degrees with a half-wave retardation plate (not shown) immediately before exiting the polarization conversion element array, and the horizontal direction in the figure. Output as linearly polarized light in the direction. The horizontal polarization component in the figure reflected by the polarization separation film is reflected again by the polarization separation film of the adjacent polarization beam splitter array, and the optical path is shifted by the array pitch and emitted. In this way, all the light beams that have passed through the polarization conversion element array 28 become horizontal linearly polarized light in the drawing.

  The light beam that has passed through the polarization conversion element array 28 enters the first cylindrical lens 29. The first cylindrical lens 29 has a refractive power only in the horizontal direction in the figure, and forms a beam compressor by combination with the second cylindrical lens 30 disposed in the traveling direction of the light beam. Therefore, the light beam incident on the first cylindrical lens 29 is compressed in the horizontal direction in the figure and guided to the liquid crystal light modulation panel 21 via the concave mirror 33 and the convex mirror 34 constituting the mirror projection system.

  The light beam that has passed through the first cylindrical lens 29 is incident on the cylindrical condenser lens 32, and the modulation surface of the light modulation panel 21 at the conjugate position of the focal line position of the cylindrical condenser lens 32 by the cylindrical condenser lens 32 as described above. Are integrated in the vertical direction in the figure.

  The light beam that has passed through the cylindrical condenser lens 32 enters the second cylindrical lens 30. As described above, the second cylindrical lens 30 has a refractive power only in the horizontal direction in the figure, and forms a beam compressor paired with the first cylindrical lens 29. As a result, the light beam is compressed in the horizontal direction in the figure, and the light beam is guided to the light modulation panel 21 via the concave mirror 33 and the convex mirror 34 constituting the mirror projection system.

  Further, the second cylindrical lens 30 forms and projects the pupil image of the first cylindrical lens 29 on the modulation surface of the liquid crystal light modulation panel 21 via the concave mirror 33 and the convex mirror 34 constituting the mirror projection system.

  Similar to the role of the second cylindrical array homogenizer 27, the second cylindrical lens 30 corrects the divergence of the divergence of the luminous flux emitted from the gas excitation light-emitting source 24 with the parabolic reflection mirror, and the first cylindrical lens 29 The light beam that has passed through the pupil is disposed so as to be surely guided to the modulation surface of the liquid crystal light modulation panel 21 via the concave mirror 33 and the convex mirror 34 constituting the mirror projection system.

  The light beam that has passed through the second cylindrical lens 30 is integrated with the integrated light beam and the cylindrical lens array via the cylindrical lens array 23 and the wavelength band space separating unit 22 that are disposed in the vicinity corresponding to the focal line position of the cylindrical condenser lens. The stripe line image generated by the image 23 is projected and transferred at the same magnification relay image by the concave mirror 33 and the convex mirror 34 constituting the mirror projection system, and is incident on the polarization beam splitter 35 and polarized in the vertical direction in the figure. The light beam is modulated by the liquid crystal light modulation panel 21 according to the image drive signal of the light modulation panel driver 37 by the polarization separation film of the polarization beam splitter 35, and the light subjected to the conversion of the polarization direction is converted by the polarization beam splitter 35. Projection lens 3 after passing through the polarization separation film Is led to the information on the modulation plane of the liquid crystal light modulation panel 21 forms an image projected on the light diffusing screen 15, an image is displayed.

  On the other hand, the behavior of the light beam in the cylindrical lens array 23 and the wavelength band space separating means 22 is as follows. The light beam is divided into regions by the cylindrical surfaces of the cylindrical lens array 23 arranged in the horizontal direction in the figure, and the lens action is received by each cylindrical surface. , Forming an array of focal lines. However, since the incident light beam has divergence, each focal line is not a thin line, and a stripe pattern having a predetermined width is formed. The stripe pattern is color-separated by the wavelength band space separation means 22, and is projected and transferred by the same magnification relay image by the concave mirror 33 and the convex mirror 34 constituting the mirror projection system, and is cylindrically applied to the light modulation surface of the liquid crystal light modulation panel 21. The aberration-free projection imaging transfer is performed in the arrangement direction of the lens array 3, but the color separation method by the wavelength band space separation means 22 is exactly the same as the principle described in the first embodiment.

  The light modulated by the pixel polarization modulation drive of the liquid crystal light modulation panel 21 is light-reflected by the ON output pixel, and the polarization direction is 90 degrees different from the polarization direction of the incident light because the linearly polarized light is subjected to phase difference modulation of π. And is transmitted to the projection lens 36 through the polarization separation film of the polarization beam splitter 35, and the light reflected light from the OFF output pixel preserves the linear polarization direction and is reflected by the polarization separation film of the polarization beam splitter 35. By returning to the light source side, light modulation of image information is performed.

  Next, the light of the ON output pixels captured by the projection lens 36 is imaged and projected on the light diffusion screen 15 to display a light modulation pattern.

  On the other hand, as a flow of a modulation signal for driving the liquid crystal light modulation panel 21, a drive signal from the light modulation panel driver 37 that converts an external video input signal (not shown) into a light modulation panel drive signal is shown through a solid line in the figure. The liquid crystal light modulation panel 21 is controlled.

  Further, as the projection display device, the screen 15 may be a reflection type or a transmission type, and if a screen having a predetermined diffusivity is used, it functions as a display device that recognizes an image by directly viewing the screen 15. Is.

  Next, the parallel pitch-shifted color-separated light flux generated by color separation by the cylindrical lens array 23 and the wavelength band space separating means 22 is used to convert the above-mentioned focal ray condensing stripe pattern of the cylindrical lens array 23 into a concave mirror constituting a mirror projection system. By projecting and transferring the same-magnification imaging relay image 33 and the convex mirror 34, the color separation stripe pattern is projected and transferred to the liquid crystal light modulation panel 21, and the cylindrical lens array 23 is not shown in the direction indicated by the arrow in FIG. By performing a reciprocal shift operation by an actuator such as a linear ultrasonic motor, the color separation stripe illumination image of the light modulation surface of the liquid crystal light modulation panel 21 moves in the same manner as described in the first embodiment. It is.

  Furthermore, the image projected and displayed on the screen 15 is temporally modulated by performing modulation corresponding to the color of each pixel of the liquid crystal light modulation panel 21 in synchronization with the color illuminated on each pixel of the liquid crystal light modulation panel 21. A full color image is displayed by mixing colors. However, in the case of modulating a color signal, modulation and temporal color mixing are performed at an early time based on ergonomics in which human visual reaction cannot catch up.

  Since the operation follow-up time of TN liquid crystal, which is generally used at present, is as slow as 5 to 20 milliseconds because of the modulation rewriting speed of the liquid crystal light modulation panel, in this embodiment, the liquid crystal light modulation panel includes a ferroelectric liquid crystal device. Or, an antiferroelectric liquid crystal device is used. In addition, a liquid crystal device having a operability using a liquid crystal molecular material having a large Δε value which is a dielectric anisotropy parameter and faster than 1 millisecond can be used.

  When the cylindrical lens array 3 is not operated, a refractive index modulation element such as a Pockels element or an optical Kerr effect element is disposed between the cylindrical lens array 23 of the illumination device and the liquid crystal light modulation panel 21 so that the Pockels element is provided. The parallel movement control of the light beam may be performed by controlling the applied electric field intensity.

  As can be seen from the operation and configuration of the projection display apparatus described above, this embodiment converts light from a light source into light in a linearly polarized state, forms a stripe optical image via a one-dimensional cylindrical lens array, An illumination system for projecting and illuminating the stripe light image onto an object to be illuminated by an imaging lens, wherein an optical path for projecting the stripe light image onto the object to be illuminated has a multilayer structure of a color polarizer and a birefringent element. A spatial light modulation element provided with a wavelength band spatial separation means, and for illuminating an object to be illuminated with a multicolor striped light image separated into a plurality of colors, and in which light modulation pixels are two-dimensionally arranged The multi-color striped light image that becomes the illumination light is displaced by the temporal displacement means, and each pixel of the spatial light modulation element is modulated and synchronized in synchronization with the input image signal and the illuminated color. The output light having the image information can be constituted by a single-plate spatial light modulator by a projection lens, and the light quantity transfer loss at the time of color separation / synthesis and the utilization efficiency of the light quantity emitted from the light source are reduced. The present invention solves the problem and makes it possible to provide a projection display device that can obtain a brightly projected display image with high utilization efficiency of light source light.

1 is a schematic perspective view of an essential part of an optical system of a projection display device provided with an illumination device according to a first embodiment of the present invention. 1 is a schematic top view of an essential part of an optical system of a projection display device provided with an illumination device according to a first embodiment of the present invention. 1 is a schematic rear view of an essential part of an optical system of a projection display device provided with an illumination device according to a first embodiment of the present invention. Optical system principal part schematic perspective view of the projection type display apparatus which has arrange | positioned the illuminating device which is the 2nd Embodiment of this invention. Schematic explaining the characteristic function of the wavelength band space separation means incorporated in the embodiment of the illumination device of the present invention Schematic explaining the state which illuminates a spatial light modulator using the illuminating device of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal light modulation panel 1E Liquid crystal light modulation panel effective arrangement | sequence area | region 2 Wavelength band space separation means 2SA Negative refractive index ellipsoidal crystal birefringence element A
2SB Negative refractive index ellipsoidal crystal birefringent element B
2PA Blue cross phase difference imparting color polarizer 2PB Green cross phase difference imparting color polarizer 2PC Red cross phase difference imparting color polarizer 2R Polarizer 3 Cylindrical lens array 4 Gas excitation light source with parabolic reflection mirror 5 Ultraviolet cut filter 6 First cylindrical Lens Array Homogenizer 7 Second Cylindrical Lens Array Homogenizer 8 Polarization Conversion Element Array 9 First Cylindrical Lens 10 Second Aspherical Cylindrical Lens 11 Third Aspherical Cylindrical Lens 12 Cylindrical Condenser Lens 13 Polarizing Beam Splitter 14 Projection Lens 15 Light Diffusing Screen 16 Light modulation panel driver 21 Liquid crystal light modulation panel 22 Wavelength band space separation means 23 Cylindrical lens array 24 Para Gas-excited emission source with a boric reflection mirror 25 UV cut filter 26 First cylindrical lens array homogenizer 27 Second cylindrical lens array homogenizer 28 Polarization conversion element array 29 First cylindrical lens 30 Second cylindrical lens 31 Luminous flux shielding plate 32 Cylindrical condenser lens 33 Concave mirror 34 Convex mirror 35 Polarizing beam splitter 36 Projection lens 37 Light modulation panel driver 100R Normal light red light beam 100G Normal light green light beam 100B Normal light blue light beam

Claims (16)

  An illumination system that converts light from a light source into linearly polarized light, forms a stripe light image via a one-dimensional cylindrical lens array, and projects and illuminates the stripe light image onto an object to be illuminated by an imaging lens. In the optical path for projecting the striped light image onto the object to be illuminated, a wavelength band space separating unit comprising a multilayer structure of a color polarizer and a birefringent element is provided, and a multicolor striped light image separated into a plurality of colors is obtained. An illumination optical system for illuminating an object to be illuminated.   The light in the linear polarization state uses non-polarized light that does not have polarized light polarized at the light source, converts the non-polarized light into a multi-stage polarization beam splitter, and one polarized wave to the other polarized wave. The illumination optical system according to claim 1, wherein the illumination optical system is generated using means called a PS conversion element comprising a combination of the above.   2. The illumination optical system according to claim 1, wherein the multicolor stripe light image is a multistage stripe light image of three primary colors of light and is a repeating periodic image of three color bands.   The wavelength band space separating unit having a multilayer structure of a color polarizer and a birefringent element includes, in order from the light incident side, a color polarizer A, a birefringent element A, a color polarizer B, a birefringent element B, and a color polarizer C. The color polarizer A, the color polarizer B, and the color polarizer C are configured by an analyzer, and are elements that give a cross polarization conversion action to only one of the three primary colors red, green, and blue, 2. The illumination optical system according to claim 1, wherein the color polarizer A, the color polarizer B, and the color polarizer C are configured to give a cross polarization conversion action to different colors.   2. The illumination optical system according to claim 1, wherein the birefringent element comprises a plate whose crystal optical axis of lithium niobate or quartz is inclined by about 45 degrees with respect to the light incident surface.   2. The illumination optical system according to claim 1, wherein the color polarizer has a multilayer laminated structure of refractive index ellipsoidal films whose optical axes are inclined in a predetermined direction in each layer called retardation stacks.   The optical band width of the striped light image generated by the one-dimensional cylindrical lens array and the shift pitch between the colors separated by the wavelength band space separation means composed of the multilayer structure of the color polarizer and the birefringent element are configured with substantially the same width. The illumination optical system according to claim 1, wherein:   2. The illumination optical system according to claim 1, wherein the light source is a short arc discharge lamp.   The multicolor stripe light which illuminates the spatial light modulation element in which the light modulation pixel is arranged two-dimensionally using the illumination optical system according to any one of claims 1 to 8 as the illumination optical system, and becomes illumination light The image is displaced by temporal displacement means, and each pixel of the spatial light modulation element is modulated in synchronization with the input image signal and the illuminated color, and output light having the modulated image information is output by the projection lens. A projection display device that projects an object and displays an image.   The means for temporally displacing the multicolor stripe light image serving as illumination light on the surface of the spatial light modulation element is a mechanical actuator for controlling displacement of a one-dimensional cylindrical lens array incorporated in the illumination optical system. The projection display device according to claim 9.   A means for temporally displacing a multicolor stripe light image as illumination light on the surface of the spatial light modulation element is to arrange a refractive index modulation element such as a Pockels element between the spatial light modulation element and the one-dimensional cylindrical lens array of the illumination optical system. The projection display apparatus according to claim 9, wherein parallel movement control of the light beam is performed.   12. The projection according to claim 9, wherein the spatial light modulator is a spatial light modulation element that modulates the intensity of light to be projected by a combination of light polarization state modulation and a light detection element such as a liquid crystal light valve element. Type display device.   13. The projection display device according to claim 12, wherein the liquid crystal light valve element is a ferroelectric liquid crystal modulation element using a ferroelectric liquid crystal.   13. The projection display device according to claim 12, wherein the liquid crystal light valve element is an antiferroelectric liquid crystal modulation element having an antiferroelectric liquid crystal phase state.   15. The projection display device according to claim 9, wherein the projected image is projected on a screen and can be recognized by diffuse reflected light having a predetermined directivity. The projection display apparatus according to claim 9, wherein the projected image is projected on a screen and can be recognized by diffuse transmitted light having a predetermined directivity.

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