US20020012082A1 - Screen and projection display apparatus using the same - Google Patents
Screen and projection display apparatus using the same Download PDFInfo
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- US20020012082A1 US20020012082A1 US08/942,567 US94256797A US2002012082A1 US 20020012082 A1 US20020012082 A1 US 20020012082A1 US 94256797 A US94256797 A US 94256797A US 2002012082 A1 US2002012082 A1 US 2002012082A1
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- Prior art keywords
- screen
- gain controller
- liquid crystal
- image
- lens
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/74—Projection arrangements for image reproduction, e.g. using eidophor
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/133371—Cells with varying thickness of the liquid crystal layer
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133526—Lenses, e.g. microlenses or Fresnel lenses
-
- 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
- G03B21/54—Accessories
- G03B21/56—Projection screens
- G03B21/60—Projection screens characterised by the nature of the surface
- G03B21/62—Translucent screens
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/13306—Circuit arrangements or driving methods for the control of single liquid crystal cells
- G02F1/13318—Circuits comprising a photodetector
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1334—Constructional arrangements; Manufacturing methods based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
Definitions
- the present invention relates to screens and projection display apparatuses using the same, and more particularly to a screen and a projection display apparatus in which screen and display a scattering liquid crystal is used in addition to a conventional diffusing plate so that a gain (explained later) of the screen becomes variable.
- FIG. 1 illustrates a conventional transmission screen 10 , a projector 11 which emits image-forming rays of light 16 , and an observer 12 who views an image displayed on the screen 1 .
- the screen 10 includes a Flesnel lens 13 , a diffusing plate 14 and a lenticular lees 15 integrated with each other.
- the Flesnel lens 13 causes the image-forming rays of light 16 emitted by the projector 11 to converge.
- the diffusing plate 14 diffuses the rays of light output the Flesnel lens 13 in a Y direction (the crosswise direction of the screen 10 ) and in a Z direction (the direction of the height of the screen 10 ).
- the lenticular lens 15 further diffuses the rays of light diffused by the diffusing plate 14 .
- an object of the present invention is to provide a screen and a projection display apparatus using the same by which screen and apparatus the aforementioned problem is eliminated.
- Another and more specific object of the present invention is to provide a screen and a projection display apparatus in which screen and apparatus a scattering liquid crystal is used in addition to a conventional diffusing plate so that the gain of the screen becomes variable.
- the present invention provides a screen comprising a gain controller for changing a ratio (gain) of luminance at a light-outgoing face of the screen to luminance at a light-incident face of the screen.
- a gain controller for changing a ratio (gain) of luminance at a light-outgoing face of the screen to luminance at a light-incident face of the screen.
- the observable area can be changed to be best adapted to the condition in which the screen is used.
- the present invention also provides a screen, wherein the gain controller comprises: a pair of transparent electrodes opposite to each other; a scattering liquid crystal disposed between the pair of transparent electrodes; and a voltage regulator for adjusting a voltage applied to the pair transparent electrodes.
- the gain of the screen can be stably controlled by adjusting the gain of the scattering liquid crystal.
- the screen may comprise a Flesnel lens at which an image-forming light is incident on the screen; and a lenticular lens from which the image-forming light outgoes from the screen, wherein the gain controller may be disposed between the lenticular lens and the Flesnel lens.
- the gain controller is provided to face the surface of the Flesnel lens from which surface the image-forming light outgoes, and the scattering liquid crystal constituting a part of the gain controller has a lenticular lens surface on its face from which face the image-forming light outgoes.
- the present invention also provides a screen further comprising a transparent base which has a surface having discrete depressions, the surface facing the Flesnel lens, wherein the gain controller is provided on the surface of the transparent base which surface faces the Flesnel lens, and the scattering liquid crystal constituting a part of the gain controller has a lenticular lens surface on its face from which face the image-forming light outgoes.
- the distance between the liquid crystal and the lenticular lens surface is virtually zero. As a result, it is possible to display an image with higher resolution than the screen in which a separate lenticular lens is provided.
- the screen may comprise a reflecting layer for reflecting the image-forming light emitted by a projector, and the gain controller is provided between the projector and the reflecting layer.
- the observable area can be changed to be best adapted to the condition in which the screen is used.
- the present invention also provides a screen further comprising a brightness detector for detecting brightness of the surroundings, wherein an output from the brightness detector is used to operate the gain controller. According to this aspect of the present invention, it is possible to adjust the brightness of a displayed image in accordance with the variation of the brightness of the surroundings so that it becomes easier for a viewer to view the display.
- the present invention also provides a projection display apparatus comprising: a body; a projector provided in the body; and a screen attached to the body, the screen comprising a gain controller for changing a ratio (gain) of luminance at a light-outgoing face of the screen to illuminance at a light-incident face of the screen.
- the gain controller of the screen of the projection display apparatus comprises: a pair of transparent electrodes opposite to each other; a scattering liquid crystal disposed between the pair of transparent electrodes; and a voltage regulator for adjusting a voltage applied to the pair transparent electrodes.
- the screen further comprises: a Flesnel lens at which an image-forming light is incident on the screen; and a lenticular lens at which the image-forming light outgoes from the screen, and the gain controller is disposed between the lenticular lens and the Flesnel lens.
- the gain controller is provided to face the surface of the Flesnel lens from which surface the image-forming light outgoes, and the scattering liquid crystal constituting a part of the gain controller has a lenticular lens surface on it face from which face the image-forming light outgoes.
- the screen further comprises a transparent base which has a surface having discrete depressions, the surface facing the Flesnel lens.
- the screen further comprises a brightness detector for detecting brightness of the surroundings, and an output from the brightness detector is used to operate the gain controller.
- the present invention provides a projection display apparatus comprising: a body; a projector provided in the body; and a screen having a gain controller for changing reflecting capability of the screen, wherein the screen further comprises a reflecting layer for reflecting the image-forming light emitted by the projector, and the gain controller is provided between the projector and the reflecting layer.
- the screen of the above projection display apparatus further comprises a brightness detector for detecting brightness of the surroundings, and an output from the brightness detector is used to operate the gain controller.
- the present invention also provides a display method in a projection display apparatus having a projector and a screen, wherein the screen has a gain controller, the display method comprising the step of: adjusting a gain of the screen by using the gain controller.
- the gain controller employed in the display method has a scattering liquid crystal being disposed between a pair of transparent electrodes, and the adjusting of the gain being carried out by adjusting a voltage applied to the pair of transparent electrodes.
- FIG. 1 illustrates a conventional screen
- FIG. 2 illustrates a screen according to a first embodiment of the present invention
- FIG. 3 illustrates how the gain of the screen of FIG. 2 is adjusted
- FIG. 4 illustrates a screen according to a second embodiment
- FIG. 5 illustrates a screen according to a third embodiment
- FIG. 6 illustrates a screen according to a fourth embodiment
- FIG. 7 illustrates a screen according to a fifth embodiment
- FIG. 8 illustrates a screen according to a sixth embodiment
- FIG. 9 illustrates a projection display apparatus which has the screen of FIG. 2;
- FIG. 10 illustrates a construction of a projector of FIG. 9.
- FIG. 2 illustrates a transmission screen 20 according to a first embodiment of the present invention.
- the screen 20 is used in a rear projection display apparatus.
- those components that are the same as the components of FIG. 1 are designated by the same reference numerals.
- the polymer dispersed liquid crystal unit 21 , the power supply 22 and the voltage regulator 23 constitute a gain controller.
- the Flesnel lens 13 Viewed from the projector 11 , the Flesnel lens 13 , the polymer dispersed liquid crystal unit 21 and the lenticular lens 15 are arranged in the stated order.
- the rays of light emitted by the projector 11 enter the screen 10 at the Flesnel lens 13 and outgoes from the screen 10 at the lenticular lens 15 .
- the polymer dispersed liquid crystal unit 21 is integral with the lenticular lens 15 , and has a transparent base 24 , a seal member 25 , a transparent mat electrode 26 disposed on the entirety of the transparent base 24 , a transparent mat electrode 27 disposed on the entirety of the lens 15 , a polymer dispersed liquid crystal 28 sealed by the seal member 25 , and terminals 29 that lead from the transparent mat electrodes 26 and 27 .
- the liquid crystal 28 has a structure in which liquid crystal droplets are dispersed in a sponge-like polymer.
- the voltage regulator 23 is connected to the terminal 29 .
- the image-forming rays of light 16 from the projector 11 are made to converge by the Flesnel lens 13 and diffused by the polymer dispersed liquid crystal unit 21 in the Y and Z directions.
- the rays of light 16 are further diffused by the lenticular lens 15 in the Y direction and then outgoes from the screen 20 so as to be directed toward the viewer 12 .
- a gain for a given spot in the liquid crystal unit 21 is defined by the following equation. luminance ⁇ ⁇ at ⁇ ⁇ light ⁇ - ⁇ outgoing ⁇ ⁇ face illuminance ⁇ ⁇ at ⁇ ⁇ light ⁇ - ⁇ incident ⁇ ⁇ face ⁇ ⁇ X ⁇ .
- a luminance ratio is defined, on an assumption that the viewer views the entirety of the screen 20 , by the following equation luminance ⁇ ⁇ at ⁇ ⁇ brightest ⁇ ⁇ spot luminance ⁇ ⁇ at ⁇ ⁇ darkest ⁇ ⁇ spot .
- An observable area is defined as an area in which it is easy for the viewer to observe the screen 20 comfortably.
- an observable area may be an area in which the luminance ratio is below 3.
- the gain When the gain is lowered, the display on the screen 20 becomes less bright. Normally, a voltage of 18 V is supplied from the voltage regulator 23 to the screen 20 . In this normal state, the screen 20 has a gain G 1 , and, as shown in FIG. 2, an observable area 31 indicated by a line 30 results.
- the voltage regulator 23 is operated to lower the output voltage to, for example, 14 V.
- the viewers who are diagonally opposite to the screen 20 are able to view the image on the screen 20 .
- the gain of the screen 20 is lowered slightly, and the brightness of the screen 20 drops slightly so that it becomes easy for the viewer to view the display comfortably. That is, the screen 20 is not excessively bright any more.
- FIG. 4 illustrates a transmission screen 40 according to a second embodiment of the present invention.
- the screen 40 has the same construction as the screen 20 of FIG. 2 except that a lenticular 41 , instead of the lenticular lens 15 , is provided.
- a lenticular 41 instead of the lenticular lens 15 .
- FIG. 4 those components that are the same as the components of FIG. 2 are designated by the same reference numerals, and the description thereof is omitted.
- the gain of the screen 40 is variable in a manner similar to the screen 20 .
- Beads 42 are dispersed in the lenticular lens 41 .
- the lenticular lens 41 diffuses the rays of light to a greater degree.
- the screen 40 is effective in case the gain cannot be satisfactorily lowered using only the polymer dispersed liquid crystal unit 21 .
- the lenticular lens 41 has a bias gain. This additional gain of the lenticular lens 41 give a margin by which the gain of the polymer dispersed liquid crystal unit 21 may be larger. Specifically, a thickness t 1 of the polymer dispersed liquid crystal 28 may be reduced accordingly so that the amount of liquid crystal 28 used in the screen 40 is reduced, resulting in a corresponding drop in the price of the screen 40 .
- FIG. 5 illustrates a transmission screen 50 according to a third embodiment.
- the screen 50 has a screen main body 50 A, the power supply 22 and the voltage regulator 23 .
- the screen main body 50 A has the Flesnel lens 13 and a polymer dispersed liquid crystal unit 51 .
- the polymer dispersed liquid crystal unit 51 has a transparent base 52 , a transparent mat electrode 53 disposed on the transparent base 52 , a solid polymer dispersed liquid crystal plate 54 whose major surface is formed to be a lenticular lens surface 54 a, and a transparent mat electrode 55 on top of the lenticular lens surface 54 a of the polymer dispersed liquid crystal 54 .
- the lenticular lens surface 54 a constitutes an exit for the rays of light.
- the gain of the polymer dispersed liquid crystal 54 is changed by adjusting a voltage applied to the transparent mat electrodes 53 and 55 .
- the gain of the screen 50 is changed so that the property of the screen 50 becomes adapted to the condition in which it is used.
- the lenticular lens surface 54 a diffuses the rays of light outgoing from the polymer dispersed liquid crystal 54 .
- the major surface of the polymer dispersed liquid crystal 54 is formed to be the lenticular lens 54 a, a lenticular lens is not provided in the screen 50 . Accordingly, the screen 50 is thinner and lighter than the screens 20 and 40 .
- the screen 50 is capable of providing an image with higher resolution than the screens 20 and 40 .
- the polymer dispersed liquid crystal unit 51 is produced in accordance with the following steps.
- a polymer dispersed liquid crystal that is dissolved using an organic solvent is cast in a die formed with discrete depressions corresponding to the lenticular lens surface.
- the transparent base 52 formed with a transparent mat electrode 53 is mounted on the upper major surface of the liquid crystal.
- FIG. 6 illustrates a transmission screen 60 according to a fourth embodiment.
- the screen 60 has a screen main body 60 A, the power supply 22 and the voltage regulator 23 .
- the screen main body 60 A has the Flesnel lens 13 and a polymer dispersed liquid crystal unit 61 .
- the polymer dispersed liquid crystal unit 61 has a flat transparent base 62 , a molded transparent base 63 , a seal member 64 and the polymer dispersed liquid crystal 28 sealed between the transparent bases 62 and 63 , the bases 62 and 63 being opposite to each other.
- a transparent mat electrode 65 is formed on the inner surface of the transparent base 62 .
- the molded transparent base 63 has a flat outer surface 63 a and an inner surface 63 b, the rays of light outgoing from the surface 63 a, and surface 63 b having discrete depressions corresponding to the lenticular lens surface.
- a transparent mat electrode 66 is formed on the surface 63 b.
- the polymer dispersed liquid crystal 28 has a lenticular lens surface 67 facing the transparent base 63 .
- the gain of the polymer dispersed liquid crystal 28 is variable by adjusting the voltage applied to the transparent mat electrodes 65 and 66 . Accordingly, the gain of the screen 60 can be changed so that the property of the screen 60 is adapted to the condition in which it is used.
- the screen 60 is capable of providing an image with high resolution.
- FIG. 7 illustrates a transmission screen 70 according to a fifth embodiment.
- the screen 70 includes: a polymer dispersed liquid crystal unit 71 constituting a screen main body 70 A; the power supply 22 ; and the voltage regulator 23 .
- the polymer dispersed liquid crystal unit 71 has the Flesnel lens 13 , the transparent base 63 , the seal member 64 , and the polymer dispersed liquid crystal 28 sealed between the Flesnel lens 13 and the transparent base 63 , the Flesnel lens 13 and the transparent base 63 being fixed to be opposite to each other.
- a transparent mat electrode 72 is formed on the inner surface of the Flesnel lens 13 .
- the gain of the polymer dispersed liquid crystal 28 is changed by adjusting the voltage applied to the transparent mat electrodes 66 and 72 .
- the gain of the screen 70 is changed so that the property of the screen 70 becomes adapted to the condition in which it is used.
- the Flesnel lens 13 of the fifth embodiment constitutes a part of the liquid crystal unit 71 . Hence, it is less likely for a deformation like a warp to occur in the Flesnel lens 13 of the fifth embodiment even after a certain period of time than in the Flesnel lens 13 of the screen 50 shown in FIG. 5 wherein the Flesnel lens 13 is separate from the liquid crystal unit 51 .
- the screen 70 has a satisfactory durability.
- FIG. 8 illustrates a reflection screen 80 , used in a front projection display apparatus or the like, according to a sixth embodiment.
- the screen 80 includes: a polymer dispersed liquid crystal unit 81 constituting the screen main body 80 A; the power supply 22 ; and the voltage regulator 23 .
- the polymer dispersed liquid crystal unit 81 includes; a transparent base 84 having a transparent mat electrode 82 on its one face and a reflecting layer 83 on its other face; and a transparent base 86 having a transparent mat electrode 85 , the transparent mat electrodes 82 and 85 being fixed to be opposite to each other, and the polymer dispersed liquid crystal 28 being sealed between the transparent bases 84 and 86 .
- the image-forming rays of light 16 from the projector 11 are incident on a surface 86 a of the transparent base 86 , an antiglare paint being applied on the surface 86 a.
- the rays of light are reflected by the reflecting layer 83 , diffused by the liquid crystal 28 , and directed toward the viewer 12 .
- the gain of the liquid crystal 28 is changed by operating the voltage regulator 23 to adjust the voltage applied to the transparent mat electrodes 82 and 85 .
- the gain of the screen 80 is changed so that the property of the screen 80 becomes adapted to the condition in which it is used.
- An aluminum film instead of the transparent mat electrode 82 of FIG. 8, may be used.
- the aluminum film provided in place of the transparent electrode 82 serves a combined function of an electrode and a reflecting layer.
- the reflecting layer 83 of FIG. 8 may be omitted.
- the polymer dispersed liquid crystal 28 may be replaced by any of the following three types of liquid crystals: (1) a dynamic scattering (DS mode) liquid crystal; (2) a ferroelectric (TS mode) liquid crystal; (3) a phase change (PC mode) liquid crystal; and (4) a liquid crystal having a thermooptical effect. All of these liquid crystals are scattering liquid crystals.
- the liquid crystal used in the third and fourth embodiments may have a lenticular lens surface facing the projector 11 .
- FIG. 9 illustrates a projection display apparatus 90 according to the first embodiment.
- a body 91 of the projection display apparatus 90 includes: the screen main body 20 A shown in FIG. 2; the power supply 22 ; the voltage regulator 23 ; a projector 92 ; reflecting mirrors 93 , 94 and 95 ; a voltage regulating knob 96 ; and a photosensor 97 (brightness detector).
- the projector 92 includes a liquid crystal panel 100 ; a light source 101 ; a dichroic mirror 102 ; a condenser lens 103 ; polarizing plates 104 and 105 ; and a projection lens 106 .
- the knob 96 in the projection display apparatus 90 is used to operate the voltage regulator 23 so that the voltage applied to the screen main body 20 A is adjusted.
- the gain of the screen main body 20 A is changed so that the property of the projection display apparatus 90 is adapted to a condition in which it is used.
- the apparatus 90 When the brightness in a room in which the apparatus 90 is located changes, the apparatus 90 operates as follows.
- the photosensor 97 detects the brightness in the room and sends an associated signal to the voltage regulator 23 . In this way, when it gets brighter in the room, the output voltage of the regulator 23 is increased. When it gets darker in the room, the output voltage of the regulator 23 is decreased.
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- Chemical & Material Sciences (AREA)
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Abstract
A screen has a screen main body, a power supply and a voltage regulator. The screen main body has a Flesnel lens, a polymer dispersed liquid crystal unit and a lenticular lens 15. The liquid crystal unit includes a polymer dispersed liquid crystal and a pair of transparent electrodes which sandwich the polymer dispersed liquid crystal. By operating the voltage regulator, a voltage applied to the electrodes is adjusted so that a gain of the liquid crystal is controlled.
Description
- 1. Field of the Invention
- The present invention relates to screens and projection display apparatuses using the same, and more particularly to a screen and a projection display apparatus in which screen and display a scattering liquid crystal is used in addition to a conventional diffusing plate so that a gain (explained later) of the screen becomes variable.
- 2. Description of the Prior Art
- FIG. 1 illustrates a
conventional transmission screen 10, a projector 11 which emits image-forming rays oflight 16, and anobserver 12 who views an image displayed on the screen 1. Thescreen 10 includes a Flesnellens 13, adiffusing plate 14 and alenticular lees 15 integrated with each other. - The Flesnel
lens 13 causes the image-forming rays oflight 16 emitted by the projector 11 to converge. Thediffusing plate 14 diffuses the rays of light output the Flesnellens 13 in a Y direction (the crosswise direction of the screen 10) and in a Z direction (the direction of the height of the screen 10). Thelenticular lens 15 further diffuses the rays of light diffused by thediffusing plate 14. - Generally, the number of viewers or brightness of the surroundings vary depending on different circumstances in which the
screen 10 is used, while the optical property of theconventional screen 10 is fixed and cannot be adjusted. - For this reason, there is a problem that the viewer may experience difficulty in viewing the image displayed on the
screen 10. - Accordingly, an object of the present invention is to provide a screen and a projection display apparatus using the same by which screen and apparatus the aforementioned problem is eliminated.
- Another and more specific object of the present invention is to provide a screen and a projection display apparatus in which screen and apparatus a scattering liquid crystal is used in addition to a conventional diffusing plate so that the gain of the screen becomes variable.
- In order to achieve the object, the present invention provides a screen comprising a gain controller for changing a ratio (gain) of luminance at a light-outgoing face of the screen to luminance at a light-incident face of the screen. According to the screen of the present invention, the observable area can be changed to be best adapted to the condition in which the screen is used.
- The present invention also provides a screen, wherein the gain controller comprises: a pair of transparent electrodes opposite to each other; a scattering liquid crystal disposed between the pair of transparent electrodes; and a voltage regulator for adjusting a voltage applied to the pair transparent electrodes. According to this aspect of the present invention, the gain of the screen can be stably controlled by adjusting the gain of the scattering liquid crystal.
- Alternatively, the screen may comprise a Flesnel lens at which an image-forming light is incident on the screen; and a lenticular lens from which the image-forming light outgoes from the screen, wherein the gain controller may be disposed between the lenticular lens and the Flesnel lens. In another alternative constitution, the gain controller is provided to face the surface of the Flesnel lens from which surface the image-forming light outgoes, and the scattering liquid crystal constituting a part of the gain controller has a lenticular lens surface on its face from which face the image-forming light outgoes. According to these aspects of the present invention, the observable area can be changed to be best adapted to the condition in which the screen is used.
- The present invention also provides a screen further comprising a transparent base which has a surface having discrete depressions, the surface facing the Flesnel lens, wherein the gain controller is provided on the surface of the transparent base which surface faces the Flesnel lens, and the scattering liquid crystal constituting a part of the gain controller has a lenticular lens surface on its face from which face the image-forming light outgoes. According to this aspect of the present invention, the distance between the liquid crystal and the lenticular lens surface is virtually zero. As a result, it is possible to display an image with higher resolution than the screen in which a separate lenticular lens is provided.
- Alternatively, the screen may comprise a reflecting layer for reflecting the image-forming light emitted by a projector, and the gain controller is provided between the projector and the reflecting layer. According to this aspect of the present invention, the observable area can be changed to be best adapted to the condition in which the screen is used.
- The present invention also provides a screen further comprising a brightness detector for detecting brightness of the surroundings, wherein an output from the brightness detector is used to operate the gain controller. According to this aspect of the present invention, it is possible to adjust the brightness of a displayed image in accordance with the variation of the brightness of the surroundings so that it becomes easier for a viewer to view the display.
- The present invention also provides a projection display apparatus comprising: a body; a projector provided in the body; and a screen attached to the body, the screen comprising a gain controller for changing a ratio (gain) of luminance at a light-outgoing face of the screen to illuminance at a light-incident face of the screen.
- Preferably, the gain controller of the screen of the projection display apparatus comprises: a pair of transparent electrodes opposite to each other; a scattering liquid crystal disposed between the pair of transparent electrodes; and a voltage regulator for adjusting a voltage applied to the pair transparent electrodes.
- Preferably, the screen further comprises: a Flesnel lens at which an image-forming light is incident on the screen; and a lenticular lens at which the image-forming light outgoes from the screen, and the gain controller is disposed between the lenticular lens and the Flesnel lens.
- Preferably, the gain controller is provided to face the surface of the Flesnel lens from which surface the image-forming light outgoes, and the scattering liquid crystal constituting a part of the gain controller has a lenticular lens surface on it face from which face the image-forming light outgoes.
- Preferably, the screen further comprises a transparent base which has a surface having discrete depressions, the surface facing the Flesnel lens.
- Preferably, the screen further comprises a brightness detector for detecting brightness of the surroundings, and an output from the brightness detector is used to operate the gain controller.
- The present invention provides a projection display apparatus comprising: a body; a projector provided in the body; and a screen having a gain controller for changing reflecting capability of the screen, wherein the screen further comprises a reflecting layer for reflecting the image-forming light emitted by the projector, and the gain controller is provided between the projector and the reflecting layer.
- Preferably, the screen of the above projection display apparatus further comprises a brightness detector for detecting brightness of the surroundings, and an output from the brightness detector is used to operate the gain controller.
- The present invention also provides a display method in a projection display apparatus having a projector and a screen, wherein the screen has a gain controller, the display method comprising the step of: adjusting a gain of the screen by using the gain controller.
- Preferably, the gain controller employed in the display method has a scattering liquid crystal being disposed between a pair of transparent electrodes, and the adjusting of the gain being carried out by adjusting a voltage applied to the pair of transparent electrodes.
- Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:
- FIG. 1 illustrates a conventional screen;
- FIG. 2 illustrates a screen according to a first embodiment of the present invention;
- FIG. 3 illustrates how the gain of the screen of FIG. 2 is adjusted;
- FIG. 4 illustrates a screen according to a second embodiment;
- FIG. 5 illustrates a screen according to a third embodiment;
- FIG. 6 illustrates a screen according to a fourth embodiment;
- FIG. 7 illustrates a screen according to a fifth embodiment;
- FIG. 8 illustrates a screen according to a sixth embodiment;
- FIG. 9 illustrates a projection display apparatus which has the screen of FIG. 2; and
- FIG. 10 illustrates a construction of a projector of FIG. 9.
- [First Embodiment]
- FIG. 2 illustrates a transmission screen20 according to a first embodiment of the present invention. The screen 20 is used in a rear projection display apparatus. In the figure, those components that are the same as the components of FIG. 1 are designated by the same reference numerals.
- The screen20 has a screen
main body 20A, apower supply 22 and avoltage regulator 23. The screenmain body 20A has a Flesnellens 13, alenticular lens 15 and a polymer dispersedliquid crystal unit 21. - The polymer dispersed
liquid crystal unit 21, thepower supply 22 and thevoltage regulator 23 constitute a gain controller. - Viewed from the projector11, the Flesnel
lens 13, the polymer dispersedliquid crystal unit 21 and thelenticular lens 15 are arranged in the stated order. The rays of light emitted by the projector 11 enter thescreen 10 at the Flesnellens 13 and outgoes from thescreen 10 at thelenticular lens 15. - The polymer dispersed
liquid crystal unit 21 is integral with thelenticular lens 15, and has atransparent base 24, aseal member 25, atransparent mat electrode 26 disposed on the entirety of thetransparent base 24, atransparent mat electrode 27 disposed on the entirety of thelens 15, a polymer dispersedliquid crystal 28 sealed by theseal member 25, andterminals 29 that lead from thetransparent mat electrodes liquid crystal 28 has a structure in which liquid crystal droplets are dispersed in a sponge-like polymer. - The
voltage regulator 23 is connected to theterminal 29. - The image-forming rays of light16 from the projector 11 are made to converge by the
Flesnel lens 13 and diffused by the polymer dispersedliquid crystal unit 21 in the Y and Z directions. The rays oflight 16 are further diffused by thelenticular lens 15 in the Y direction and then outgoes from the screen 20 so as to be directed toward theviewer 12. - A description will now be given of a gain, a luminance ratio and an observable area.
-
- It is to be noted that the greater the gain, the smaller a degree that the rays of light are diffused. The smaller the gain, the greater the degree that the rays of light are diffused, resulting in a darker image viewed from the front.
-
- It is to be noted that the greater the luminance ratio, the more irregular the brightness of display.
- An observable area is defined as an area in which it is easy for the viewer to observe the screen20 comfortably. For example, an observable area may be an area in which the luminance ratio is below 3.
- A description will now be given of the operation of the polymer dispersed
liquid crystal unit 21. - When the level of a voltage applied to the
transparent mat electrodes - A description will now be given of the operation of the screen20 having the aforementioned construction.
- When the
voltage regulator 23 is operated to adjust the voltage applied to thetransparent mat electrodes liquid crystal unit 21 changes as indicated by the line I, resulting in the gain of the screen 20 changing as indicated by the line II of FIG. 3 A - When the gain of the screen20 changes, the diffusing behavior of the rays of light changes, and the observable area changes.
- Generally, a lower gain results in a wider observable area.
- When the gain is lowered, the display on the screen20 becomes less bright. Normally, a voltage of 18 V is supplied from the
voltage regulator 23 to the screen 20. In this normal state, the screen 20 has a gain G1, and, as shown in FIG. 2, anobservable area 31 indicated by aline 30 results. - A description will now be given of operations executed in different situations.
- (1) Case 1—the number of viewers increases
- When the number of viewers increases to the extent that some viewers are diagonally opposite to the screen20, the
voltage regulator 23 is operated to lower the output voltage to, for example, 14 V. - As a result of this operation, the gain of the screen20 is lowered to G2 indicated in FIG. 3.
- Consequently, the observable area expands in a direction indicated by
arrows 33 of FIG. 2. Anobservable area 35 delineated by aline 34 results. - Thus, the viewers who are diagonally opposite to the screen20 are able to view the image on the screen 20.
- (2) Case 2—the surroundings become darker
- When the surroundings become darker, the
voltage regulator 23 is operated to lower the output voltage slightly. - As a result, the gain of the screen20 is lowered slightly, and the brightness of the screen 20 drops slightly so that it becomes easy for the viewer to view the display comfortably. That is, the screen 20 is not excessively bright any more.
- [Second Embodiment]
- FIG. 4 illustrates a
transmission screen 40 according to a second embodiment of the present invention. - The
screen 40 has the same construction as the screen 20 of FIG. 2 except that a lenticular 41, instead of thelenticular lens 15, is provided. In FIG. 4, those components that are the same as the components of FIG. 2 are designated by the same reference numerals, and the description thereof is omitted. - The gain of the
screen 40 is variable in a manner similar to the screen 20. -
Beads 42 are dispersed in thelenticular lens 41. In comparison to thelenticular lens 15, thelenticular lens 41 diffuses the rays of light to a greater degree. - The
screen 40 is effective in case the gain cannot be satisfactorily lowered using only the polymer dispersedliquid crystal unit 21. - The
lenticular lens 41 has a bias gain. This additional gain of thelenticular lens 41 give a margin by which the gain of the polymer dispersedliquid crystal unit 21 may be larger. Specifically, a thickness t1 of the polymer dispersedliquid crystal 28 may be reduced accordingly so that the amount ofliquid crystal 28 used in thescreen 40 is reduced, resulting in a corresponding drop in the price of thescreen 40. - [Third Embodiment]
- FIG. 5 illustrates a
transmission screen 50 according to a third embodiment. - In the figure, those components that are the same as the components of FIG. 3 are designated by the same reference numerals, and the description thereof is omitted.
- The
screen 50 has a screenmain body 50A, thepower supply 22 and thevoltage regulator 23. - The screen
main body 50A has theFlesnel lens 13 and a polymer dispersedliquid crystal unit 51. - The polymer dispersed
liquid crystal unit 51 has atransparent base 52, atransparent mat electrode 53 disposed on thetransparent base 52, a solid polymer dispersedliquid crystal plate 54 whose major surface is formed to be alenticular lens surface 54 a, and atransparent mat electrode 55 on top of thelenticular lens surface 54 a of the polymer dispersedliquid crystal 54. Thelenticular lens surface 54 a constitutes an exit for the rays of light. - Similarly to the first embodiment, the gain of the polymer dispersed
liquid crystal 54 is changed by adjusting a voltage applied to thetransparent mat electrodes screen 50 is changed so that the property of thescreen 50 becomes adapted to the condition in which it is used. - The
lenticular lens surface 54 a diffuses the rays of light outgoing from the polymer dispersedliquid crystal 54. - Since the major surface of the polymer dispersed
liquid crystal 54 is formed to be thelenticular lens 54 a, a lenticular lens is not provided in thescreen 50. Accordingly, thescreen 50 is thinner and lighter than thescreens 20 and 40. - In the above-described construction, in which a lenticular lens is not provided, the distance, in a direction of the thickness of the
screen 50, between theliquid crystal 54 and thelenticular lens surface 54 a is virtually zero. Therefore, thescreen 50 is capable of providing an image with higher resolution than thescreens 20 and 40. - The polymer dispersed
liquid crystal unit 51 is produced in accordance with the following steps. - (1) A polymer dispersed liquid crystal that is dissolved using an organic solvent is cast in a die formed with discrete depressions corresponding to the lenticular lens surface.
- (2) The
transparent base 52 formed with atransparent mat electrode 53 is mounted on the upper major surface of the liquid crystal. - (3) Volatilize the organic solvent so that the liquid crystal becomes solid.
- (4) Remove the liquid crystal from the die and form the
transparent mat electrode 55 on the lenticular lens surface of the liquid crystal by deposition. - [Fourth Embodiment]
- FIG. 6 illustrates a
transmission screen 60 according to a fourth embodiment. - In the figure, those components that are the same as the components of FIG. 2 are designated by the same reference numerals, and the description thereof is omitted.
- The
screen 60 has a screenmain body 60A, thepower supply 22 and thevoltage regulator 23. - The screen
main body 60A has theFlesnel lens 13 and a polymer dispersedliquid crystal unit 61. - The polymer dispersed
liquid crystal unit 61 has a flattransparent base 62, a moldedtransparent base 63, aseal member 64 and the polymer dispersedliquid crystal 28 sealed between thetransparent bases bases - A
transparent mat electrode 65 is formed on the inner surface of thetransparent base 62. - The molded
transparent base 63 has a flatouter surface 63 a and aninner surface 63 b, the rays of light outgoing from thesurface 63 a, andsurface 63 b having discrete depressions corresponding to the lenticular lens surface. Atransparent mat electrode 66 is formed on thesurface 63 b. - The polymer dispersed
liquid crystal 28 has alenticular lens surface 67 facing thetransparent base 63. - Similarly to the first embodiment, the gain of the polymer dispersed
liquid crystal 28 is variable by adjusting the voltage applied to thetransparent mat electrodes screen 60 can be changed so that the property of thescreen 60 is adapted to the condition in which it is used. - Similarly to the
screen 50 of FIG. 5, since the surface of theliquid crystal 28 is formed to be alenticular lens surface 67, thescreen 60 is capable of providing an image with high resolution. - [Fifth Embodiment]
- FIG. 7 illustrates a
transmission screen 70 according to a fifth embodiment. - In the figure, those components that are the same as the components of FIGS. 2 and 6 are designated by the same reference numerals, and the description thereof is omitted.
- The
screen 70 includes: a polymer dispersedliquid crystal unit 71 constituting a screenmain body 70A; thepower supply 22; and thevoltage regulator 23. - The polymer dispersed
liquid crystal unit 71 has theFlesnel lens 13, thetransparent base 63, theseal member 64, and the polymer dispersedliquid crystal 28 sealed between theFlesnel lens 13 and thetransparent base 63, theFlesnel lens 13 and thetransparent base 63 being fixed to be opposite to each other. - A
transparent mat electrode 72 is formed on the inner surface of theFlesnel lens 13. - Similarly to the fourth embodiment, the gain of the polymer dispersed
liquid crystal 28 is changed by adjusting the voltage applied to thetransparent mat electrodes screen 70 is changed so that the property of thescreen 70 becomes adapted to the condition in which it is used. - If a warp occurs in the
Flesnel lens 13, an irregularity in the resolution of the screen results. It will be noted that theFlesnel lens 13 of the fifth embodiment constitutes a part of theliquid crystal unit 71. Hence, it is less likely for a deformation like a warp to occur in theFlesnel lens 13 of the fifth embodiment even after a certain period of time than in theFlesnel lens 13 of thescreen 50 shown in FIG. 5 wherein theFlesnel lens 13 is separate from theliquid crystal unit 51. - Accordingly, the
screen 70 has a satisfactory durability. - [Sixth Embodiment]
- FIG. 8 illustrates a
reflection screen 80, used in a front projection display apparatus or the like, according to a sixth embodiment. - The
screen 80 includes: a polymer dispersed liquid crystal unit 81 constituting the screenmain body 80A; thepower supply 22; and thevoltage regulator 23. - The polymer dispersed liquid crystal unit81 includes; a
transparent base 84 having atransparent mat electrode 82 on its one face and a reflectinglayer 83 on its other face; and atransparent base 86 having atransparent mat electrode 85, thetransparent mat electrodes liquid crystal 28 being sealed between thetransparent bases - The image-forming rays of light16 from the projector 11 are incident on a
surface 86 a of thetransparent base 86, an antiglare paint being applied on thesurface 86 a. The rays of light are reflected by the reflectinglayer 83, diffused by theliquid crystal 28, and directed toward theviewer 12. - The gain of the
liquid crystal 28 is changed by operating thevoltage regulator 23 to adjust the voltage applied to thetransparent mat electrodes screen 80 is changed so that the property of thescreen 80 becomes adapted to the condition in which it is used. - An aluminum film, instead of the
transparent mat electrode 82 of FIG. 8, may be used. In this construction, the aluminum film provided in place of thetransparent electrode 82 serves a combined function of an electrode and a reflecting layer. Thus, the reflectinglayer 83 of FIG. 8 may be omitted. - [Variation]
- In the foregoing embodiments, the polymer dispersed
liquid crystal 28 may be replaced by any of the following three types of liquid crystals: (1) a dynamic scattering (DS mode) liquid crystal; (2) a ferroelectric (TS mode) liquid crystal; (3) a phase change (PC mode) liquid crystal; and (4) a liquid crystal having a thermooptical effect. All of these liquid crystals are scattering liquid crystals. - The liquid crystal used in the third and fourth embodiments may have a lenticular lens surface facing the projector11.
- FIG. 9 illustrates a
projection display apparatus 90 according to the first embodiment. - A body91 of the
projection display apparatus 90 includes: the screenmain body 20A shown in FIG. 2; thepower supply 22; thevoltage regulator 23; aprojector 92; reflectingmirrors voltage regulating knob 96; and a photosensor 97 (brightness detector). - As shown in FIG. 10, the
projector 92 includes aliquid crystal panel 100; alight source 101; adichroic mirror 102; acondenser lens 103; polarizingplates projection lens 106. - The
knob 96 in theprojection display apparatus 90 is used to operate thevoltage regulator 23 so that the voltage applied to the screenmain body 20A is adjusted. - As a result, the gain of the screen
main body 20A is changed so that the property of theprojection display apparatus 90 is adapted to a condition in which it is used. - When the brightness in a room in which the
apparatus 90 is located changes, theapparatus 90 operates as follows. - The
photosensor 97 detects the brightness in the room and sends an associated signal to thevoltage regulator 23. In this way, when it gets brighter in the room, the output voltage of theregulator 23 is increased. When it gets darker in the room, the output voltage of theregulator 23 is decreased. - Consequently, when the brightness in the room increases, the gain of the screen
main body 20A is automatically increased. As a result, the display becomes brighter and it becomes easier for the viewer to view the display. When the brightness in the room decreases, the gain of thescreen 20A is automatically decreased. As a result, the display becomes darker and it becomes easier for the viewer to view the display. - The present invention is not limited to the above described embodiments, and variations and modifications may be made without departing from the scope of the present invention.
Claims (20)
1. A screen comprising a gain controller for changing a ratio (gain) of luminance at a light-outgoing face of the screen to illuminance at a light-incident face of the screen.
2. The screen as claimed in claim 1 , wherein said gain controller comprises:
a pair of transparent electrodes opposite to each other;.
a scattering liquid crystal disposed between said pair of transparent electrodes; and
a voltage regulator for adjusting a voltage applied to said pair of transparent electrodes.
3. The screen claimed in claim 2 , further comprising:
a Flesnel lens at which an image-forming light is incident on the screen; and
a lenticular lens at which the image-forming light outgoes from the screen,
wherein said gain controller is disposed between said lenticular lens and said Flesnel lens.
4. The screen as claimed in claim 2 , further comprising:
a Flesnel lens at which the image-forming light is incident on the screen,
wherein said gain controller is provided to face the surface of said Flesnel lens from which surface the image-forming light outgoes, and
the scattering liquid crystal constituting a part of said gain controller has a lenticular lens surface on its face from which face the image-forming light outgoes.
5. The screen as claimed in claim 2 , further comprising:
a Flesnel lens at which the image-forming light is incident on the screen; and
a transparent base which has a surface having discrete depressions, said surface facing said Flesnel lens,
wherein said gain controller is provided on said surface of said transparent base which surface faces said Flesnel lens, and
the scattering liquid crystal constituting a part of said gain controller has a lenticular lens surface on its face from which face the image-forming light outgoes.
6. The screen as claimed in claim 2 , further comprising a reflecting layer for reflecting the image-forming light emitted by a projector,
wherein said gain controller is provided between said projector and said reflecting layer.
7. The screen as claimed in claim 1 , further comprising a brightness detector for detecting brightness of the surroundings,
wherein an output from said brightness detector is used to operate said gain controller.
8. The screen as claimed in claim 2 , further comprising a brightness detector for detecting brightness of the surroundings,
wherein an output from said brightness detector is used to operate said gain controller.
9. The screen as claimed in claim 6 , further comprising a brightness detector for detecting brightness of the surroundings,
wherein an output from said brightness detector is used to operate said gain controller.
10. A projection display apparatus comprising:
a body;
a projector provided in said body; and
screen attached to said body, said screen comprising a gain controller for changing a ratio (gain) of luminance at a light-outgoing face of the screen to illuminance at a light-incident face of the screen.
11. The projection display apparatus as claimed in claim 10 ,
wherein said gain controller of said screen comprises:
a pair of transparent electrodes opposite to each other;
a scattering liquid crystal disposed between said pair of transparent electrodes; and
a voltage regulator for adjusting a voltage applied to said pair transparent electrodes.
12. The projection display apparatus as claimed in claim 11 ,
wherein said screen further comprises:
a Flesnel lens at which an image-forming light is incident on the screen; and
a lenticular lens at which the image-forming light outgoes from the screen, and
said gain controller is disposed between said lenticular lens and said Flesnel lens.
13. The projection display apparatus as claimed in claim 11 ,
wherein said screen fur her comprises:
a Flesnel lens at which the image-forming light is incident on the screen, and
said gain controller is provided to face the surface of said Flesnel lens from which surface the image-forming light outgoes, and
the scattering liquid crystal constituting a part of said gain controller has a lenticular lens surface of its face from which face the image-forming light outgoes.
14. The projection display apparatus as claimed in claim 11
wherein said screen further comprises:
a Flesnel lens at which the image-forming light is incident on the screen; and
a transparent base which has a surface having discrete depressions, said surface facing said Flesnel lens, and
said gain controller is provided on said surface of said transparent base which surface faces said Flesnel lens, and
the scattering liquid crystal constituting a part of said gain controller has a lenticular lens surface on its face from which face the image-forming light outgoes.
15. The projection display apparatus as claimed in claim 10 , wherein said screen further comprises a brightness detector for detecting brightness of the surroundings, and
an output from said brightness detector is used to operate said gain controller.
16. The projection display apparatus as claimed in claim 11 , wherein said screen further comprises a brightness detector for detecting brightness of the surroundings, and
an output from said brightness detector is used to operate said gain controller.
17. A projection display apparatus comprising:
a body;
a projector provided in said body; and
a screen having a gain controller for changing reflecting capability of the screen;
wherein said screen further comprises a reflecting layer for reflecting the image-forming light emitted by said projector, and
said gain controller is provided between said projector and said reflecting layer.
18. The projection display apparatus as claimed in claim 17 , wherein said screen further comprises a brightness detector for detecting brightness of the surroundings, and
an output from said brightness detector is used to operate said gain controller.
19. A display method in a projection display apparatus having a projector and a screen, wherein the screen has a gain controller, said display method comprising the step of:
adjusting a gain of the screen by using said gain controller.
20. The display method as claimed in claim 19 , wherein said gain controller has a scattering liquid crystal being disposed between a pair of transparent electrodes, and the adjusting of the gain being carried out by adjusting a voltage applied to said pair of transparent electrodes.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/942,567 US6392726B2 (en) | 1994-03-16 | 1997-10-01 | Screen and production display apparatus using the same |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6-046198 | 1994-03-16 | ||
JP6046198A JPH07253621A (en) | 1994-03-16 | 1994-03-16 | Screen and projection type display device using the same |
US40221095A | 1995-03-10 | 1995-03-10 | |
US08/942,567 US6392726B2 (en) | 1994-03-16 | 1997-10-01 | Screen and production display apparatus using the same |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US40221095A Continuation | 1994-03-16 | 1995-03-10 |
Publications (2)
Publication Number | Publication Date |
---|---|
US20020012082A1 true US20020012082A1 (en) | 2002-01-31 |
US6392726B2 US6392726B2 (en) | 2002-05-21 |
Family
ID=12740387
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/942,567 Expired - Fee Related US6392726B2 (en) | 1994-03-16 | 1997-10-01 | Screen and production display apparatus using the same |
Country Status (3)
Country | Link |
---|---|
US (1) | US6392726B2 (en) |
JP (1) | JPH07253621A (en) |
KR (1) | KR100221930B1 (en) |
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KR100786860B1 (en) * | 2002-05-08 | 2007-12-20 | 삼성에스디아이 주식회사 | Autostereoscopic display appratus having varifocal lens |
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Publication number | Publication date |
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KR100221930B1 (en) | 1999-09-15 |
KR950028501A (en) | 1995-10-18 |
US6392726B2 (en) | 2002-05-21 |
JPH07253621A (en) | 1995-10-03 |
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