WO2007138940A1 - 画像表示装置 - Google Patents
画像表示装置 Download PDFInfo
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- WO2007138940A1 WO2007138940A1 PCT/JP2007/060483 JP2007060483W WO2007138940A1 WO 2007138940 A1 WO2007138940 A1 WO 2007138940A1 JP 2007060483 W JP2007060483 W JP 2007060483W WO 2007138940 A1 WO2007138940 A1 WO 2007138940A1
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- Prior art keywords
- pixel
- laser light
- light
- aperture
- image display
- Prior art date
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/48—Laser speckle optics
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
- G02B27/102—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources
- G02B27/1046—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources for use with transmissive spatial light modulators
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
- G02B27/102—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources
- G02B27/1046—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources for use with transmissive spatial light modulators
- G02B27/1053—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources for use with transmissive spatial light modulators having a single light modulator for all colour channels
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/14—Beam splitting or combining systems operating by reflection only
- G02B27/145—Beam splitting or combining systems operating by reflection only having sequential partially reflecting surfaces
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/0006—Arrays
- G02B3/0037—Arrays characterized by the distribution or form of lenses
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/20—Lamp housings
- G03B21/2006—Lamp housings characterised by the light source
- G03B21/2033—LED or laser light sources
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/28—Reflectors in projection beam
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3129—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] scanning a light beam on the display screen
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3141—Constructional details thereof
- H04N9/315—Modulator illumination systems
- H04N9/3161—Modulator illumination systems using laser light sources
Definitions
- the present invention relates to an image display device such as a television receiver or a video projector.
- Projection displays that project images on a screen are widely used as image display devices such as television receivers and video projectors.
- image display devices such as television receivers and video projectors.
- a projection display has a problem that a power source using a lamp light source has a short lifetime and a limited color reproduction region and a low light use efficiency.
- the laser light source has a longer life than the lamp light source and has a strong directivity, so it is easy to improve the light utilization efficiency. Further, since the laser light source exhibits monochromaticity, it is possible to display a clear image with a large color reproduction area.
- Speckle noise is fine granular noise that can be seen by the observer's eyes due to interference between scattered lights when scattered on a laser power screen.
- Speckle noise is noise in which grains of a size determined by the F (F number) of the observer's eyes and the wavelength of the laser light source are randomly arranged, and obstructs the capturing of images on the observer's power screen. Causes serious image degradation.
- Patent Document 1 proposes that a substantial aperture ratio of a two-dimensional light modulation element is increased by using a laser light source and a microlens array, and diffracted light is reduced by high efficiency of light use efficiency.
- laser light such as speckle noise.
- Patent Document 1 Japanese Patent Laid-Open No. 2002-268003
- An object of the present invention is to provide a highly reliable image display device that can reduce speckle noise and improve light utilization efficiency by using a small two-dimensional light modulation element. .
- An image display device includes a laser light source, a spatial light modulation element that modulates laser light emitted from the laser light source, a display surface that displays the modulated light, and the laser.
- An optical pixel aperture enlarging member that performs luminance dispersion of the laser light while guiding light to the aperture of each pixel of the spatial light modulator, and the space corresponding to each pixel of the image displayed on the display surface
- a display pixel aperture enlargement portion that optically enlarges the light modulated by the aperture of each pixel of the light modulation element, and displays on the display surface by the optical pixel aperture enlargement member and the display pixel aperture enlargement portion. Control so that the brightness of a part of each pixel of the image is less than three times the average value of the brightness of the entire pixel area
- the substantial aperture ratio of each pixel is improved by performing luminance dispersion of the laser light while guiding the laser light emitted from the laser light to each pixel of the spatial light modulator.
- the utilization efficiency of laser light is enhanced and the light resistance is enhanced.
- the luminance concentration of each pixel of the image displayed on the display surface can be relaxed, the degree of speckle noise recognition by the viewer can be reduced.
- FIG. 1 is a schematic diagram showing a schematic configuration of an image display device according to Embodiment 1 of the present invention.
- FIG. 2 is a diagram showing luminance fluctuation in a pixel due to speckle noise.
- FIG. 3 shows a microlens included in a microlens array constituting an optical pixel aperture enlarging member. It is a schematic diagram which shows schematic structure of a process.
- FIG. 4 is a schematic diagram showing another schematic configuration of a microlens included in a microlens array constituting an optical pixel aperture enlarging member.
- FIG. 5 is a schematic diagram showing another schematic configuration of a microlens included in a microlens array constituting an optical pixel aperture enlarging member.
- FIG. 6 is a schematic diagram showing another schematic configuration of the microlens included in the microlens array constituting the optical pixel aperture enlarging member.
- FIG. 7 is a schematic diagram showing another schematic configuration of the microlens included in the microlens array constituting the optical pixel aperture enlarging member.
- FIG. 8A is a schematic diagram showing a schematic configuration of a display pixel aperture enlarged portion.
- FIG. 8B is a diagram illustrating the operation of the display pixel aperture enlargement unit of FIG. 8A.
- FIG. 8C is a diagram showing a state of pixel enlargement by the display pixel aperture enlargement part of FIG. 8A.
- FIG. 9A is a schematic diagram showing another schematic configuration of the display pixel aperture enlarged portion.
- FIG. 9B is a diagram illustrating the operation of the display pixel aperture enlargement unit of FIG. 9A.
- FIG. 9C is a diagram showing a state of pixel enlargement by the display pixel aperture enlargement part of FIG. 9A.
- FIG. 10A is a schematic diagram showing another schematic configuration of the display pixel aperture enlarged portion.
- FIG. 10B is a diagram illustrating the operation of the display pixel aperture enlargement unit in FIG. 10A.
- FIG. 10C is a diagram showing a state of pixel enlargement by the display pixel aperture enlargement part of FIG. 10A.
- FIG. 11A is a schematic diagram showing another schematic configuration of the display pixel aperture enlarged portion.
- FIG. 11B is a diagram illustrating the operation of the display pixel aperture enlargement unit in FIG. 11A.
- FIG. 11C is a diagram showing a state of pixel enlargement by the display pixel aperture enlargement part of FIG. 11A.
- FIG. 12 is a schematic diagram showing a schematic configuration of an image display device according to Embodiment 2 of the present invention.
- FIG. 13 is a schematic diagram showing a schematic configuration of an image display apparatus according to Embodiment 3 of the present invention.
- FIG. 1 is a schematic diagram showing a schematic configuration of image display device 100 according to Embodiment 1 of the present invention.
- Image display apparatus 100 according to the present embodiment relates to a projection display (laser display) using a laser light source.
- the light emitted from the RGB three-color laser light sources la to lc illuminates the two-dimensional light modulation element 6.
- the illumination optical system 2 includes a beam deflection control means 3, an optical integrator 4, and a projection optical system 5, and illuminates the two-dimensional light modulation element 6 by uniformizing the light from the laser light sources la to lc.
- the projection optical system 5 includes a mirror 51 and a field lens 52.
- the two-dimensional light modulation element 6 modulates each color of RGB, and the modulated light of each color is multiplexed by the dichroic prism 9.
- the combined light is enlarged on the screen (display surface) 10 by the projection optical system 8 to display a color image.
- the two-dimensional light modulation element 6 is provided with an optical pixel aperture enlarging member, which will be described later. Improvement of the target aperture ratio is attempted. Further, a display pixel aperture enlargement section 7 to be described later is disposed between the dichroic prism 9 and the projection optical system 8, and the light combined by the dichroic prism 9 is passed through the display pixel aperture enlargement section 7 to the screen. By projecting onto the screen 10, the brightness uniformity within the display pixels on the screen 10 is enhanced.
- the optical pixel aperture enlarging member and the display pixel aperture enlarging portion 7 will be described.
- the two-dimensional light modulation element 6 is a small two-dimensional light modulation element capable of displaying a high-definition image by reducing the pixel pitch. As a result of the downsizing, the optical aperture ratio of each pixel is reduced. Need improvement. For example, an element in which the pixel aperture ratio of each pixel is less than 80% is included in the two-dimensional light modulation element 6.
- the pixel aperture ratio indicates the ratio of the area of the area (opening) in which light used for display is modulated in the pixel of the two-dimensional light modulation element, and is expressed by the following equation:
- Pixel aperture ratio Effective area contributing to display in one pixel Z Area of the entire region of one pixel
- the region that does not contribute to the display includes the metal wiring of each pixel electrode and individual pixels. It is occupied by elements to be controlled separately.
- a small, high-definition two-dimensional light modulator with a small pixel pitch results in a low pixel aperture ratio. Therefore, as described above, the two-dimensional light modulation element 6 is provided with the optical pixel aperture enlarging member, and guides the light that illuminates the two-dimensional light modulation element 6 to the opening of each pixel. Increase the amount of light modulated by.
- the display pixel aperture enlargement unit 7 controls the partial luminance in the pixels displayed on the screen 10 to be less than three times the average value of the luminance of the entire pixels.
- a laser light source unlike a lamp light source, has a very small light source area, and therefore has excellent condensing characteristics and coherence. For this reason, luminance concentration occurs in a part of the opening of the pixel of the two-dimensional light modulation element.
- the luminance concentration in the pixel on the screen 10 is suppressed and the two-dimensional light modulator 6
- the light utilization efficiency is improved by increasing the amount of light modulated at the aperture of the pixel.
- the luminance concentration is configured to cause the luminance concentration to occur in a part of the opening of the two-dimensional light modulation element as much as possible.
- the luminance concentration is a problem.
- the partial luminance within a pixel on the display surface refers to an average luminance within an arbitrary region of the pixel.
- the partial luminance is controlled to be less than three times the average luminance value of the entire pixel. For an arbitrary area for calculating partial luminance, extract an area of 10-30% of the pixel area!
- the partial luminance and average luminance value of the pixels on the display surface can be obtained by photographing the display surface with a CCD camera or the like and obtaining the received light intensity.
- the partial luminance when displaying green with high visibility is less than three times the average luminance value of the entire pixel.
- the partial luminance when the colors of the laser light source are each displayed in a single color is less than three times the average luminance value of the entire pixel.
- interference patterns such as moire and speckles may also be shot. However, eliminate the interference pattern so that it does not cause noise in luminance calculation, or measure it as a pattern with sufficient strength. .
- the power that can suppress glare in the bright part pattern of the speckle noise preferably less than twice, more preferably Is less than 1.5 times. 1. By making it less than 5 times, viewers do not feel local glare.
- the area where the partial luminance in the pixel on the display surface is less than 1Z3 of the average luminance value is less than 20% of the area of the pixel. Even if the area of the dark portion in each pixel is small, it is possible to prevent the luminance of some areas in the pixel from increasing.
- the optical pixel aperture enlarging member is a microlens array force in which a plurality of one-to-one microphone lenses corresponding to the aperture of each pixel of the two-dimensional light modulator 6 are arranged in an array, and the two-dimensional light modulator 6 Arranged on the projection optical system 5 side.
- Fig. 4-7 shows the optical pixel aperture expansion member The structure of the microlens contained in a microlens array is shown.
- the micro lenses 63b to 63e shown in FIGS. 4 to 7 guide the light irradiated to the two-dimensional light modulation element 6 to the opening 61 of the pixel, thereby being blocked by the light blocking unit 62 and losing the amount of irradiation light. To prevent that.
- the micro lens 63a shown in Fig. 3 is excellent in preventing the diverging light from a lamp light source or the like from being blocked by the light blocking portion 62 as much as possible. It matches with the center of the opening 61. For this reason, in the case of a laser light source, the condensing point is concentrated on the point, the luminance of the incident light is not dispersed, and the intensity distribution in the opening 61 becomes non-uniform.
- luminance dispersion is performed as in the micro lenses 63b to 63e shown in FIGS.
- the condensing points of the micro lenses are discretely or continuously connected.
- the light emitted from the laser light source is directional light emitted from the point light source, and the angle of the light incident on the microlens can be controlled.
- the intensity distribution of the opening 61 can be designed according to the shape of the microlens by allowing the light emitted from the laser light source to be incident as substantially parallel light.
- the condensing points of the microlenses 63b to 63e are discretely or continuously connected, so that the intensity is almost uniform in the opening 61, and the luminance concentration in the opening 61 is suppressed. be able to.
- Microlenses with discrete or continuous condensing points suppress the concentration of luminance in the two-dimensional light modulator 6 and increase the power density at the beam condensing location that occurs when a laser light source is used. Can prevent the two-dimensional light modulation element 6 from deteriorating.
- the condensing point in this embodiment refers to a point where light gathers when collimated light is incident on the microlens.
- this is the only image display device having a two-dimensional light modulation element having an optical pixel aperture enlargement member made of a microlens in which the condensing points are discretely or continuously connected, and a laser light source.
- a two-dimensional light modulation element having an optical pixel aperture enlargement member made of a microlens in which the condensing points are discretely or continuously connected, and a laser light source.
- the microlens 63b in Fig. 4 has a substantially flat shape with a large radius of curvature at the inner periphery, a shape with refractive power at the outer periphery, and a condensing point at the inner periphery and the outer periphery. Are connected. It should be noted that the case where the condensing point where the refractive power is in the inner peripheral portion becomes infinity is included in the state where the condensing points are dispersedly connected.
- the microlens 63c in FIG. 5 has a conical lens shape, and the condensing points are continuously connected to the inner peripheral force and the outer periphery, and each pixel generates a light beam having an angle that avoids the light shielding portion 62.
- the microlens 63d in FIG. 6 has a negative refracting power at the inner peripheral portion and a positive refracting power at the outer peripheral portion, and generates a divergent beam that the inner peripheral force cannot be displaced by the light shielding portion 62. From the outer periphery, a light collecting beam is created.
- the inner peripheral part has a condensing point in the ⁇ direction from the incident surface
- the outer peripheral part has a condensing point in the + direction
- the condensing points are discrete.
- the radius of curvature is different between the inner peripheral portion and the outer peripheral portion, and the condensing point where the radius of curvature of the inner peripheral portion is small comes to the incident surface side.
- the condensing points are discretely connected at the inner periphery and the outer periphery.
- the layers on the incident side of the microlenses 63b to 63e are not shown, but the microlenses 63b to 63e are made of a layer having a refractive index different from that of the microphone-lens constituent material, The
- the incident-side component layer is higher than the refractive index of the microlens, the force that produces the bending force opposite to that shown in Figs.4-7, the same as in Figs.4-7, by reversing the microlens shape in Figs.4-7 An effect is obtained.
- the distance between the condensing points is longer than the pixel pitch.
- the luminance concentration points of the aperture 61 are dispersed, and even when the projection optical system 8 enlarges and displays on the screen 10, it always displays in a state where luminance concentration does not occur.
- Figures 4 to 6 show examples of the distance D between the focal points.
- the distance D between the condensing points is longer than the pixel pitch P.
- Pixel pitch P is the distance between the centers of adjacent pixels. D is the distance between two points when there are two condensing points, and the distance between the longest condensing points when there are three or more points.
- the condensing points are continuous like the micro lens 63c, the distance between the longest converging end points is taken.
- the lens has a negative refractive power as in the inner periphery of the micro lens 63d, the focal position in one direction is taken as one of the condensing points and D is taken.
- the condensing point of the microlens according to the present embodiment is closer to the outer periphery of the lens than to the inner periphery of the lens. It is preferable that the lens entrance surface force is far away. Specifically, like the microlenses 63c and 63d, it is preferable that the condensing point on the outer peripheral portion where the condensing point on the inner peripheral portion is close to the incident surface of the microlens is located far from the incident surface force. In the case where there are three or more condensing points, it is preferable that the condensing point is gradually distant from the incident surface force of the microlens in order toward the outer periphery as in the micro lens 63c.
- the distribution of the condensing points of the microlens of the present embodiment is broader than the long wavelength (green or red 500 to 700 nm) with respect to the blue laser wavelength (400 to 500 nm). It is preferable that the force be reduced. Specifically, when the distance Db between the condensing points of the microlens with respect to the blue laser light is the distance Dg, Dr between the condensing points with respect to the green laser light and the red laser light,
- the condensing point distribution is broadened so that power concentration does not occur particularly for blue laser light having the shortest wavelength in RGB.
- Blue laser light is more condensing than other colors of laser light and has high energy. Therefore, degradation of the two-dimensional light modulator due to adhesion caused by thermal and chemical reactions occurs.
- deterioration due to the blue laser can be prevented by expanding the condensing point distribution with respect to the blue laser light more than the green and red laser lights.
- the image display device 100 preferably has a display pixel aperture enlargement section 7 between the screen 10 and the two-dimensional light modulation element 6.
- the display pixel aperture enlargement unit 7 is inserted.
- the display pixel aperture enlargement section 7 can be incorporated in the projection optical system 8.
- the display pixel aperture enlargement portion 7 occupies the pixel aperture portion displayed on the screen 10 rather than the pixel aperture ratio of the two-dimensional light modulator 6. The luminance uniformity of display pixels is improved by increasing the display area ratio.
- FIGS. 8A, 9A, 10A, and 11A are diagrams and diagrams showing a schematic configuration of the display pixel aperture enlargement unit 7.
- FIGS. 8A, 9A, 10A, and 11A are diagrams and diagrams showing a schematic configuration of the display pixel aperture enlargement unit 7.
- 8B, FIG. 9B, FIG. 10B, and FIG. 11B are diagrams showing the operation of the display pixel aperture enlargement unit 7, and FIG. 8C, FIG. 9C, FIG. 10C, and FIG. FIG.
- the display pixel aperture enlarging unit 7 uses the birefringence of the crystal to give incident light to the optical axis of the crystal, and to give different angles or position shifts between the ordinary ray and the extraordinary ray, so that the two-dimensional light modulation element Incident light is displayed on the screen 10 by making the area ratio occupied by the openings of the pixels of the screen 10 larger than the ratio of the openings of the pixels 6.
- the area of the opening that is enlarged by the display pixel opening enlargement portion 7 may be larger than one pixel, but is preferably enlarged to an area of 2 pixels or less. If the image is enlarged beyond 2 pixels, the resolution of the image will deteriorate and a blurred image will be displayed.
- the area ratio of the openings displayed on the screen 10 is 80 to 200% with respect to the area of the entire area of one pixel.
- the display pixel aperture enlarged portion 7 is formed on the screen 10 more than the aperture ratio of the two-dimensional light modulator 6.
- the focal point and aberration of the projection optical system 8 can be set, a screen thicker than the focal depth can be used, or the two-dimensional light modulator 6 and the screen 10 can be used.
- a movable part may be provided in between, and the area ratio of the opening perceived by a person may be made larger by time integration by moving the opening over time.
- the small two-dimensional light modulation element having the optical pixel aperture enlargement member described above since the luminance tends to concentrate on the center of the aperture, the aperture center itself is shifted. As shown in FIG.
- a means for causing a different angle or position shift due to birefringence or a means for shifting the central portion with respect to time by a movable portion is preferable.
- the shift amount of the opening center portion is such that the position interval of the image of the opening center portion on the screen is 10 to 90% of the pixel pitch on the screen. If it is smaller than 10%, the amount of deviation at the center of the opening is insufficient, and the concentration of luminance cannot be sufficiently relaxed, and if it is larger than 90%, the resolution of the image deteriorates.
- the display pixel aperture enlargement unit 7 preferably uses birefringence as shown in FIGS. 8A to 11C in combination with the two-dimensional light modulation element 6 using polarized light. With such a configuration, in the opening It is possible to shift the position of the central part on the screen 10 without moving means.
- the birefringent plates in FIGS. 8A to 11C show different refractive indices for ordinary rays and extraordinary rays with respect to the optical axis.
- optical crystals such as quartz, sapphire and LiNbO are used.
- the display pixel aperture enlargement unit 7 converts linearly polarized light into circularly polarized light or random polarized light and emits it.
- Speckle noise generated when using a laser light source is interference noise, and orthogonally polarized light does not interfere with each other. Therefore, by irradiating screen 10 with linearly polarized light as circularly or randomly polarized light, speckle noise is generated. It can be reduced. Since the light emitted from the laser light sources la to lc of the image display device 100 of the present embodiment is linearly polarized light, it is preferably converted into circularly polarized light or random polarized light for display.
- the rear projection type image display device has a mirror in the projection optical system and the casing, and the reflectivity varies depending on the polarization direction. Therefore, uniform reflection regardless of the polarization direction can be achieved by using circularly polarized light or random polarized light. Light can be guided to the display surface at a rate.
- the 10A to 10C includes a ⁇ 4 wavelength plate 73d, and the emitted light is circularly polarized light.
- the ⁇ 4 wavelength plate 73d preferably supports all the laser light wavelengths used in the image display device 100, and in this embodiment, a polymer liquid crystal material is used.
- the emitted circularly polarized light may be slightly flat.
- a birefringent plate having a wedge angle is used.
- the birefringent plate having a wedge angle in this embodiment is a birefringent plate whose one surface is inclined with respect to the optical axis, and the wedge angle direction indicates the direction of the inclined angle.
- the birefringent plate has a crystal optical axis in a plane perpendicular to the incident light (xy plane), and the thickness of the birefringent plate varies depending on the position where the light beam passes.
- a birefringent plate having a wedge angle is used as a pair with a plate that compensates the wedge angle (for example, birefringent plates 74a and 74b in FIG. 11A), but at least one (for example, the birefringent plate in FIG. 11A).
- One of 74a and 74b) only needs to have birefringence. At least one has birefringence Thus, random polarization and separation of the angle of the light beam are possible. It is a preferable form for low cost to make one side a general glass material without birefringence.
- the plate for compensating the wedge angle is also made of the same material card having birefringence, and the optical axes of the material having a set of wedge angles are orthogonal.
- the birefringent plates 71a and 71b in FIG. 8A are made of the same material, and the optical axes are 45 ° and 135 ° in the xy plane.
- the first birefringent plate on which incident light is first incident has its optical axis oriented in the 45 ° direction with respect to the incident linearly polarized light direction. By setting the direction to 45 °, the light beam can be evenly separated.
- the display pixel aperture enlarging portion 71 shown in FIG. 8A includes four birefringent plates 71a to 71d having wedge angles, and the x-axis direction of the pixel is determined by the wedge angles of the four birefringent plates 71a to 71d. By separating the angle in the y-axis direction, the opening of the display pixel is enlarged. In addition, linearly polarized laser light is emitted as random polarized light.
- the pair of birefringent plates 71a and 71b and the pair of birefringent plates 71c and 71d are each composed of the same birefringent material, have orthogonal optical axes, and have a relationship of compensating for wedge angle.
- the pair of birefringent plates 71a and 71b and the pair of birefringent plates 71c and 71d are perpendicular to the angular direction of the wedge. That is, the birefringent plates 71a and 71b are in the X sectional direction, and the birefringent plates 71c and 71d are in the y sectional direction. With this relationship, the birefringent plates 71a and 71b are angle-separated in the X-axis direction, the birefringent plates 71c and 71d are angle-separated in the y-axis direction, and the center of the opening of the display pixel is shifted for display. To do.
- the display pixel aperture enlargement portion 71 in FIG. 8A is preferably configured to allow angle separation and complex random polarization.
- the optical axis directions of the four birefringent plates 71a to 71d and the incident polarization direction are indicated by arrows.
- the optical axes of the birefringent plates 71a to 71d are in the xy plane (in the plane orthogonal to the incident light), and when the linearly polarized light in the x-axis direction is incident, the birefringent plate 71a is in the 45 ° direction, and the birefringent plate 71b Is directed to the 135 ° direction, the birefringent plate 71c is directed to the 0 ° direction, and the birefringent plate 71d is directed to the 90 ° direction.
- the pair of birefringent plates 71a and 71b and the pair of birefringent plates 71c and 71d are preferable forms having optical axes orthogonal to each other and symmetric with respect to the separation angle.
- the display pixel aperture enlarging portion 72 shown in FIG. 9A includes two parallel birefringent plates 72a and 72b and two birefringent plates 72c and 72d having a wedge angle.
- the double-folded plates 72c and 72d having a wedge angle perform angle separation in the X-axis direction and random polarization of the emitted light.
- the parallel birefringent plates 72a and 72b have an optical axis in a direction inclined with respect to the incident light direction (z-axis), and emit by shifting the positions of ordinary light rays and extraordinary rays. An ordinary ray goes straight, and an extraordinary ray is shifted and emitted.
- the shifting direction depends on the optical axis direction of the birefringent plates 72a and 72b, and the birefringent plate 72a is shifted obliquely upward in the xy plane and the birefringent plate 72b is shifted obliquely downward in the xy plane.
- the shift distance depends on the inclination of the optical axis, the refractive index with respect to ordinary light and extraordinary light, and the thickness of the birefringent plates 72a and 72b, and can be controlled.
- FIG. 9B shows an example of the optical axes of the birefringent plates 72a to 72d with arrows.
- the birefringent plate 72a when linearly polarized light in the x-axis direction is incident, the birefringent plate 72a has an optical axis in the X-axis 45 °, z-axis 45 ° direction, and the birefringent plate 72b has an X-axis 45 ° and z-axis 45 ° direction.
- the two parallel birefringent plates 72a and 72b separate the light beam at an appropriate position by having optical axes at different angles on the xy plane.
- the display pixel aperture enlarging portion 73 shown in FIG. 10A includes three parallel birefringent plates 73a, 73b and 73c, and a ⁇ 4 plate 73d.
- the ⁇ 4 plate 73d circularly polarizes the outgoing light from the birefringent plates 73a, 73b and 73c.
- Birefringent plates Birefringent plates 73a, 73b, and 73c shift the position of incident light in the x-axis direction and the y-axis direction, and shift the position of the center of the opening of the screen 10.
- the first and second birefringent plates 73a and 73b are the same as the birefringent plates 72a and 72b of the display pixel aperture enlargement 72 in FIG. 9A, and the optical axis of the third birefringent plate 73c is in the xz plane. By tilting to, the position is shifted in the X-axis direction.
- the optical axis of the third birefringent plate 73c is X axis — 180.
- the z axis is in the 45 ° direction.
- the display pixel aperture enlarging portion 74 of FIG. 11A also has two birefringent plates 74a and 74c and two isotropic material plates 74b and 74d.
- the birefringent plates 74a and 74b have a wedge angle in the X-axis direction, thereby performing angle separation in the X-axis direction and random polarization, and the birefringent plates 74c and 74d have a wedge angle in the y-axis direction. Angle separation in the axial direction and random polarization are performed, and the position of the center of the opening of the screen 10 is shifted.
- the two isotropic material plates 74b and 74d can be made of a common glass material, and are preferable examples that can be manufactured at low cost.
- the isotropic material plates 74b and 74d are provided with birefringent plates 74a and 7d to prevent reflection loss. It is preferable that the refractive index is substantially equal to that of 4c.
- the two birefringent plates 74a and 74c of the display pixel aperture enlargement portion 74 are in a preferred form in which the wedge angles are orthogonal to each other and biaxial angular separation and complicated random polarization are brought about.
- the birefringent plate and the ⁇ 4 plate that form the display pixel aperture enlargement portion 7 may be joined using a transparent adhesive having a refractive index equivalent to that of the birefringent plate material. It is preferable to apply an antireflection coating for the wavelength of the laser light source to be used on the entrance / exit surface of the display pixel aperture enlarged portion
- the beam deflection control unit 3 that temporally controls the beam deflection direction of the laser beam is changed to at least one laser light source la ⁇ : Lc, the two-dimensional light modulation element 6, and the like. It is preferable to have between.
- the beam deflection control unit 3 is provided between the laser light source la ⁇ : Lc and the optical integrator 4. Light is collected at the condensing point of the two-dimensional light modulation element 6 by the optical pixel aperture enlargement member, but the incident angle to the microlens of the optical pixel aperture enlargement member is changed temporally by the beam deflection control unit 3.
- the beam deflection control unit 3 a movable mirror, a movable lens, a movable diffusing plate, and the like can be used. However, other elements can be used as long as the deflection direction of the beam can be temporally changed.
- FIG. 12 is a schematic diagram showing a schematic configuration of the image display apparatus according to Embodiment 2 of the present invention.
- the image display apparatus 200 according to the present embodiment is similar to the image display apparatus 100 according to the first embodiment described above.
- the force is related to a projection display (laser display) using a laser light source.
- the difference is that there is one two-dimensional light modulator.
- one two-dimensional light modulation element 6 is used for three colors of light from the RGB three-color laser light sources la to lc.
- the three colors are combined by the dichroic mirror 21, guided through the lens 22, mirror, etc., and guided to the beam deflection control unit 3, through the optical integrator 4 and the projection optical system 5, and then optically.
- the two-dimensional light modulation element 6 having a pixel aperture enlarged portion is illuminated.
- RGB laser light The sources la to lc emit laser light sequentially, and the two-dimensional light modulation element 6 is used in a time-sharing manner.
- the light emitted from the two-dimensional light modulation element 6 is magnified on the screen 10 by the projection optical system 8 including the display pixel aperture enlarging portion 7.
- FIG. 13 is a schematic diagram showing a schematic configuration of the image display apparatus according to Embodiment 3 of the present invention.
- An image display device 200a according to the present embodiment is obtained by applying the image display device according to the second embodiment to a rear projection type projection display (laser display).
- the light emitted from the projection optical system 8 is displayed on the transmission screen 11 after passing through the rear mirror 12.
- the projection optical system 8 includes a mirror 81 that turns the optical path together with the lens group.
- the display pixel aperture enlarging portion 7 may be a reflective element integrated with the folding mirror 81.
- the display pixel aperture enlarging portion 7 may be a mirror that uses a folding mirror as a movable mirror and displays the center of the aperture with time shift. Also good.
- linearly polarized light is incident and the emitted light is made circularly polarized light or random polarized light as shown in the display pixel aperture enlarged portions 71 to 74 in FIGS. 8A to 11C using birefringence. is there. Since the rear projection type has a rear mirror and a folding mirror as shown in Fig. 13, the linearly polarized light is circularly or randomly polarized and the light is applied to the display surface with a uniform reflectance regardless of the polarization direction. U, who can lead and prefer more.
- the display pixel aperture enlarging section 7 can also have the function of the transmissive screen 11 which is the display surface.
- the transmissive screen 11 which is the display surface.
- two or more diffusion layers of the transmissive screen 11 are placed and separated.
- the opening recognized by the viewer is displayed with the area ratio per pixel enlarged through multilayer diffusion.
- the distance between the diffusion layers is 100 m or more, preferably 200 m or more, more preferably 500 m or more.
- the effect of enlarging the opening increases as the interval increases. However, if the interval is too large, the image resolution is deteriorated and the total thickness of the transmissive screen 11 is increased and the size is increased. Therefore, the interval is preferably 5 mm or less.
- the total thickness of the transmissive screen 11 is preferably lmm or more.
- the present invention can be used for an image display device using a monochromatic laser light source, and can also be used for an image forming device using three or more color laser light sources.
- the laser light sources of the respective colors may be configured with a plurality of laser element forces that emit substantially the same wavelength, or may be configured with a single element force.
- the image of the two-dimensional light modulation element is magnified by the projection optical system and displayed on the display surface.
- the emitted light may be displayed directly on the display surface.
- the two-dimensional light modulation element may be not only a transmission type but also a reflection type, but preferably uses a polarized light using a liquid crystal. Combined with the linear polarization of the laser light source, efficient modulation is possible.
- the illumination optical system for illuminating the two-dimensional light modulation element is not limited to the above-described embodiment, and it is sufficient that the two-dimensional light modulation element can be illuminated with light from the laser light source.
- a liquid crystal display panel including a two-dimensional light modulation element forms a display surface, and the two-dimensional light modulation element is illuminated with light having a laser light source power within the liquid crystal display panel.
- Embodiments 1 to 3 described above the configuration for displaying an image on a screen has been described.
- a two-dimensional image may be displayed in addition to the screen.
- the display surface can be anywhere. For example, it can be used when displaying directly on a wall, liquid, or other retina.
- Embodiments 1 to 3 described above it is possible to provide an image display device that uses a laser light source, is colorful, and is free from glare on the display surface with high light utilization efficiency.
- an image display apparatus includes a laser light source, a spatial light modulation element that modulates laser light emitted from the laser light source force, a display surface that displays the modulated light, and An optical pixel aperture enlarging member that distributes the luminance of the laser beam while guiding the laser beam to the aperture of each pixel of the spatial light modulator, and the image corresponding to each pixel of the image displayed on the display surface
- a display pixel aperture enlarging unit that optically expands the light modulated by the aperture of each pixel of the spatial light modulation element, and displays on the display surface by the optical pixel aperture enlarging member and the display pixel aperture enlarging unit.
- a portion of each pixel in the resulting image The brightness of the area is controlled to be less than 3 times the average value of the brightness of the entire pixel area.
- the substantial aperture ratio of each pixel is improved by performing luminance dispersion of the laser light while guiding the laser light emitted from the laser light to each pixel of the spatial light modulator.
- the utilization efficiency of laser light is enhanced and the light resistance is enhanced.
- the luminance concentration of each pixel of the image displayed on the display surface can be relaxed, the degree of speckle noise recognition by the viewer can be reduced.
- the optical pixel aperture enlarging member is disposed in one-to-one correspondence with each pixel of the spatial light modulator, and a plurality of microlenses that guide the laser beam to the aperture of the corresponding pixel.
- the microlens has a plurality of condensing points, and a plurality of condensing points of laser light condensed by the microlens.
- a distance between the most separated light collection points among the plurality of light collection points is longer than a distance between adjacent pixels of the spatial light modulation element.
- the luminance concentration points due to the laser light at the openings of the pixels are dispersed.
- the luminance concentration at each pixel of the image displayed on the display surface is alleviated.
- the plurality of condensing points are positioned further away from the incident surface force as the incident position of the laser beam on the incident surface of the microlens moves from the central portion of the incident surface to the outer peripheral portion.
- Laser light emitted from the laser light source includes blue laser light, green laser light, and red laser light, and the distance between the condensing points farthest among the plurality of condensing points is Different for each of the blue laser light, green laser light and red laser light, the distance Db between the condensing points for the blue laser light, the distance Dg between the condensing points for the green laser light, and It is preferable that the distance Dr between the condensing points for the red laser light satisfies the following relationship.
- the spatial light modulation element can be prevented from being deteriorated by the blue laser light by spreading the condensing point distribution for the blue laser light more than that of the green laser light and the red laser light.
- the aperture ratio of each pixel of the spatial light modulator is preferably less than 80%.
- the display pixel aperture enlargement unit preferably converts the modulated light into circularly polarized light.
- the display pixel aperture enlargement unit preferably converts the modulated light into random polarized light.
- the display pixel aperture enlargement section includes at least one birefringent plate having a wedge angle, and the modulated light is incident on the birefringent plate to be converted into two lights having different emission angles. It is preferable to expand the modulated light by separating.
- the display pixel aperture enlarged portion includes two birefringent plates having wedge angles orthogonal to each other.
- biaxial light beam separation and complex randomly polarized light can be created.
- the apparatus further includes a deflection direction variable unit that is disposed between the laser light source and the spatial light modulation element and temporally changes a beam deflection direction of the laser light emitted from the laser light source. preferable.
- the image display apparatus can achieve speckle noise removal and improvement of light utilization efficiency using a small two-dimensional light modulation element, so that images such as video projectors, television receivers, and liquid crystal panels can be obtained. It can be suitably used for a display device or the like.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/301,904 US8029141B2 (en) | 2006-05-26 | 2007-05-23 | Image display apparatus that controls luminance of a partial area of each pixel to be below threefold of an average luminance value of the entire pixel |
JP2008517869A JP5144508B2 (ja) | 2006-05-26 | 2007-05-23 | 画像表示装置 |
CN200780018221XA CN101449196B (zh) | 2006-05-26 | 2007-05-23 | 图像显示装置 |
Applications Claiming Priority (2)
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JP2006-146397 | 2006-05-26 | ||
JP2006146397 | 2006-05-26 |
Publications (1)
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WO2007138940A1 true WO2007138940A1 (ja) | 2007-12-06 |
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PCT/JP2007/060483 WO2007138940A1 (ja) | 2006-05-26 | 2007-05-23 | 画像表示装置 |
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US (1) | US8029141B2 (ja) |
JP (1) | JP5144508B2 (ja) |
CN (1) | CN101449196B (ja) |
WO (1) | WO2007138940A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US20100265467A1 (en) * | 2009-04-16 | 2010-10-21 | Microvision, Inc. | Laser Projection Source with Polarization Diversity Element for Speckle Reduction |
JP2011247953A (ja) * | 2010-05-24 | 2011-12-08 | Mitsubishi Electric Corp | ビーム出射位置調整装置およびビーム出射位置調整方法 |
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KR101294234B1 (ko) * | 2007-12-04 | 2013-08-16 | 엘지디스플레이 주식회사 | 3차원 영상 표시장치 |
CN102436074B (zh) * | 2010-09-29 | 2016-08-03 | 株式会社尼康 | 光斑减少装置以及投影仪 |
TW201232153A (en) * | 2011-01-26 | 2012-08-01 | Hon Hai Prec Ind Co Ltd | Laser projecting device |
DE112012004012T5 (de) * | 2011-10-19 | 2014-07-17 | Innovia Security Pty Ltd | Sicherheitsvorrichtung |
US10008822B2 (en) * | 2014-10-10 | 2018-06-26 | The Boeing Company | Laser system and method for controlling the wave front of a laser beam |
US10613275B2 (en) * | 2018-03-30 | 2020-04-07 | Microsoft Technology Licensing, Llc | Changing pulse width to reduce visible interference |
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- 2007-05-23 JP JP2008517869A patent/JP5144508B2/ja not_active Expired - Fee Related
- 2007-05-23 WO PCT/JP2007/060483 patent/WO2007138940A1/ja active Application Filing
- 2007-05-23 US US12/301,904 patent/US8029141B2/en not_active Expired - Fee Related
- 2007-05-23 CN CN200780018221XA patent/CN101449196B/zh not_active Expired - Fee Related
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JPH09508476A (ja) * | 1994-01-31 | 1997-08-26 | エス・ディー・エル・インコーポレイテッド | レーザ照明ディスプレイシステム |
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US20100265467A1 (en) * | 2009-04-16 | 2010-10-21 | Microvision, Inc. | Laser Projection Source with Polarization Diversity Element for Speckle Reduction |
US8287128B2 (en) * | 2009-04-16 | 2012-10-16 | Microvision, Inc. | Laser projection source with polarization diversity element for speckle reduction |
JP2011247953A (ja) * | 2010-05-24 | 2011-12-08 | Mitsubishi Electric Corp | ビーム出射位置調整装置およびビーム出射位置調整方法 |
Also Published As
Publication number | Publication date |
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US8029141B2 (en) | 2011-10-04 |
JPWO2007138940A1 (ja) | 2009-10-01 |
CN101449196B (zh) | 2011-09-21 |
CN101449196A (zh) | 2009-06-03 |
JP5144508B2 (ja) | 2013-02-13 |
US20100231861A1 (en) | 2010-09-16 |
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