JP2010079185A - Display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display system that enables a high contrast display without depending on an operating environment, and that is low in power consumption. <P>SOLUTION: The display system 1 includes: a display 3 comprising a reaction layer 8 consisting of photochromic materials, which has absorbability for light of substantially all visible wavelength region in the state without irradiation of visible light, which generates a first reaction that the absorbability of light of a specific visible wavelength region disappears by the irradiation of visible light, and which generates a second reaction for generating the absorbability of light of a visible wavelength region by the irradiation of ultraviolet light after the generation of the first reaction; and a visible light source 9 for emitting visible light. Further, the system includes a projector 4 for projecting the visible light on the display 3 from the visible light source 9 and for writing an image on the reaction layer 8, and an ultraviolet light source 5 for irradiating the reaction layer 8 with the ultraviolet light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display system.

  In recent years, display on a large screen display has attracted much attention. For example, display devices such as electronic paper, flat panel display (FPD), projectors, and light emitting diode arrays are used for applications such as advertising and signage. In electronic paper and FPD, an active matrix substrate having the same size as the display area must be manufactured, and it is technically and costly difficult to realize a large screen display of 100 inches or more. On the other hand, in the case of a projector, a large screen display can be realized at a relatively low cost.

  However, in the case of a projector, black is expressed by not irradiating light. Therefore, when external light hits the screen, a portion that should be displayed black becomes bright, so-called black floating occurs. This black floating causes problems such as a decrease in contrast and a decrease in reproducibility of dark gradation. As described above, there is a problem that the image quality of the projector is greatly influenced by the use environment, and it is desired to provide a projection system capable of ensuring high contrast regardless of the use environment.

As an example of a screen that can achieve high contrast, it has high reflection characteristics for light in the three primary color wavelength regions of light emitted from the projector, and high absorption characteristics for light in wavelength regions other than the three primary color wavelength regions There has been proposed a screen provided with a reflective diffusion layer having a thickness (for example, see Patent Document 1). There is also disclosed a screen that realizes a high contrast by sandwiching a layer made of a polymer and a liquid crystal between two transparent substrates and scattering only light polarized in the alignment direction of the polymer (for example, Patent Documents). 2).
JP 2004-170959 A JP-A-6-301005

  However, when the screens of Patent Documents 1 and 2 are used, it is hard to maintain the contrast of the current projector, and it is difficult to obtain more contrast. In particular, when the projector is used outdoors, the luminance is inferior to that of other display devices, and thus there is a drawback that it is difficult to see the image. Furthermore, since the image disappears when the projection of the light is stopped, the projector must be constantly lit in consideration of applications such as advertising and signage. Therefore, it has been desired to provide a system that increases power consumption and can further reduce power consumption.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a display system with low power consumption capable of high-contrast display regardless of the use environment.

The display system of the present invention has absorptivity with respect to light in almost all visible wavelength regions in a state where no visible light is irradiated. A first reaction in which absorbency disappears occurs, and the photochromic material is generated in which a second reaction in which the absorbency of light in the visible wavelength region is restored by irradiation with the ultraviolet light after the first reaction has occurred. A display unit including a reaction layer; a visible light source that emits the visible light; a projection device that projects the visible light from the visible light source on the display unit and writes an image on the reaction layer; and the reaction layer. And an ultraviolet light source for irradiating the ultraviolet light.
The “image” referred to in this specification refers to not only pictures and photos but also all display contents including characters, symbols, and the like.

  By the way, photochromism refers to a phenomenon in which the optical properties of a substance change reversibly by light irradiation, and a substance that causes such a phenomenon is referred to as a photochromic material. Application of photochromic materials to fields such as light control glass and optical disks is being studied. The inventor of the present invention has applied the photochromic material to a display body that can be written and erased, and has created a display system including the display body.

  In the present invention, by irradiating the reaction layer made of a photochromic material having predetermined characteristics with visible light from the projection device, the light absorption in a specific visible wavelength region disappears in the visible light irradiation region on the reaction layer. A first reaction occurs. At this time, the irradiation region changes to a state in which light in a specific visible wavelength region is reflected or transmitted, and an image is written on the display body. When this type of photochromic material is used, a state where light in a specific visible wavelength region is reflected or transmitted is maintained until the next irradiation with ultraviolet light, that is, an image is maintained. Therefore, irradiation of visible light from the projection device can be stopped after an image is written on the display body. When the display is to be erased, a second reaction in which the absorption of light in the visible wavelength region is restored occurs by irradiating the display body with ultraviolet light from an ultraviolet light source. The image is erased. When the image is rewritten, the image may be projected again from the projection device onto the display body.

  As described above, according to the display system of the present invention, an image with excellent contrast can be obtained because an image written directly on the display body can be displayed in addition to the image by the projection light. In addition, since the projection apparatus can be turned off after the image is written, power consumption can be reduced. Further, even if the display body is enlarged, it is only necessary to form the reaction layer uniformly on the display body, and it is not necessary to build an active matrix circuit, so that an inexpensive large screen display system can be realized. Furthermore, even if the display body itself has one specification, the size, shape, resolution, number of pixels, etc. of the screen can be freely set depending on which projector is combined.

Moreover, in this invention, what can irradiate the said ultraviolet light to the whole area | region of the said reaction layer can be used as said ultraviolet light source.
According to this configuration, the entire image can be erased and rewritten with a simple configuration that only controls irradiation and non-irradiation of ultraviolet light without strictly controlling the ultraviolet light source.

Moreover, in this invention, what can selectively irradiate the said ultraviolet light only to the specific area | region of the said reaction layer can be used as the said ultraviolet light source.
According to this configuration, since the ultraviolet light is selectively irradiated only on a specific region of the reaction layer, the image can be partially erased and rewritten, and the display image can be enhanced.

Moreover, in this invention, what irradiates the said ultraviolet light only to the area | region where the specific image was displayed based on the image signal supplied to the said projection apparatus can be used as the said ultraviolet light source.
According to this configuration, since the ultraviolet light is irradiated only to the area where the specific image is displayed based on the image signal, only the specific image in the entire image can be erased and rewritten according to the content of the image. it can.

In the present invention, an ultraviolet light blocking layer that blocks the ultraviolet light may be provided on the viewing side of the display body and the ultraviolet light source.
According to this configuration, since the ultraviolet light blocking layer is provided on the viewing side of the display body and the ultraviolet light source, when external light such as sunlight enters the display body, the ultraviolet light component contained in the external light It is possible to prevent the image from being erased. Further, it is possible to prevent the ultraviolet light emitted from the ultraviolet light source from leaking to the viewer side.

Moreover, in this invention, the titanium oxide film | membrane which carry | supported silver particle can be used as a photochromic material which comprises the said reaction layer.
According to this configuration, since the titanium oxide film supporting silver particles is used as the photochromic material, the first reaction and the second reaction described above can be surely expressed with the oxidation-reduction reaction.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The display system of this embodiment is an example in which a front projector is used as a projection device, and an ultraviolet light source is independently installed outside the projector.
FIG. 1 is a side view showing a schematic configuration of the display system of the present embodiment. FIGS. 2A to 2C are diagrams for explaining a procedure from image display to image erasure of the display system. FIG. 3 is a diagram for explaining a driving method of the display system. In the following drawings, in order to show each component in an easy-to-see manner, the scale of each component, the ratio of dimensions, and the like are appropriately changed from actual ones.
In the following description, the viewing side (observer side) of the display system may be referred to as the front surface, and the side opposite to the viewing side (observer side) may be referred to as the back surface.

  As shown in FIG. 1, the display system 1 of the present embodiment includes a housing 2, a display body 3, a projector 4 (projection device), an ultraviolet light source 5, and a UV cut filter 6 (ultraviolet light blocking layer). It is equipped with. The housing 2 is formed in a frame shape, a flat display body 3 is installed on the back side of the housing 2, and a UV cut filter 6 that blocks ultraviolet light is installed on the front side of the housing 2. ing.

  The display body 3 is obtained by forming a reaction layer 8 made of a photochromic material on the surface of a support plate 7 made of, for example, a glass plate. In the present embodiment, a photochromic material is used in which silver nanoparticles are supported on a nanoporous titanium oxide film having a minute space with a size of several to several tens of nanometers. When the display 3 is manufactured, titanium oxide nanoparticles are coated on a support plate 7 such as a glass plate together with a binder, and this is heated and cured to form a nanoporous titanium oxide film. Next, when a solution containing silver ions is applied onto the titanium oxide film and irradiated with ultraviolet light, the silver ions are reduced by the photocatalytic reaction of titanium oxide to form silver nanoparticles. At this time, nanopores (nanometer-sized pores) of the titanium oxide film serve as templates, and silver nanoparticles having various sizes and shapes are generated.

  In the reaction layer 8 formed by the above procedure, each silver nanoparticle has various sizes and shapes, so that each of them expresses the property of absorbing light in different wavelength ranges. Therefore, the reaction layer 8 as a whole exhibits the property of absorbing light in almost all visible wavelength regions and exhibits a blackish brown color. For example, when the reaction layer 8 is irradiated with light having a strong green intensity, for example, only particles that can absorb light in the green wavelength range are excited by electrons and deprived of oxygen to be colorless. Oxidized to silver ions. Then, since green light is not absorbed, the portion of the reaction layer 8 irradiated with light appears green (corresponding to “first reaction” in the claims). Thereafter, when the reaction layer 8 is irradiated with ultraviolet light, colorless silver ions are reduced, and light absorption in almost all visible wavelength regions is restored. As a result, the entire reaction layer 8 including the region that appears green is dark brown. (Corresponding to “second reaction” in the claims).

  In the present embodiment, the surface of the display body 3 on which the reaction layer 8 is formed is disposed on the viewing side. In the lower part on the viewing side of the display body 3 in the space surrounded by the housing 2, the display body 3, and the UV cut filter 6, a projector 4 that emits visible light for image formation and ultraviolet light for image erasure are provided. An ultraviolet light source 5 that emits light is installed. The projector 4 used here may be a front-type projector. For example, the type and number of light modulators (light valves), the type of light source, and the like are not particularly limited. An example of a projector having a white light source 9 (visible light source) will be described. The ultraviolet light source 5 is set so that the emitted ultraviolet light is irradiated on the entire surface of the display body 3.

Next, a procedure for displaying an image using the display system configured as described above will be described.
When displaying an image, as shown in FIG. 2A, visible light is emitted from the projector 4, and arbitrary images A and B are projected on the display body 3. At this time, in the reaction layer 8 of the display body 3, as described above, a reaction occurs in which the absorptivity with respect to the irradiated light in the specific wavelength region disappears, and thus images A and B are written on the display body 3. And since the state with which the light absorbency with respect to the light of a specific wavelength area | region disappeared in each area | region on the display body 3, as shown in FIG.2 (b), even if it turns off the projector 4 and stops projection, Images A and B are still displayed on the display 3. Thereafter, when erasing the images A and B, as shown in FIG. 2C, if the ultraviolet light source 5 irradiates the display 3 with ultraviolet light, the reaction layer 8 emits light in almost all visible wavelengths. A reaction in which the absorbability is restored occurs, and the images A and B can be erased. When rewriting the image, the image may be projected again from the projector 4 onto the display body 3.

  Therefore, when the display system 1 is driven, as shown in FIG. 3, after the visible light is projected from the projector 4 with a predetermined luminance as the first stage and an image is written, the projector 4 is temporarily set as the second stage. In the third stage, the ultraviolet light source 5 is irradiated with ultraviolet light with a predetermined luminance to erase the image. For example, by repeating the cycles of the first to third stages, it is possible to realize an advertisement, signage, or the like in which the display image is switched every predetermined time.

  According to the display system 1 of the present embodiment, since the display is maintained with the image written on the display body 3 in addition to the image by the projection light from the projector 4, an image with excellent contrast can be obtained. In addition, since the projector 4 can be turned off after the image is written, even when used for a long-time display such as an advertisement or signage, the power consumption can be reduced, and a system with less environmental load can be realized. . In addition, since the ultraviolet light source 5 is configured to irradiate the entire region of the display body 3 with ultraviolet light, it is a simple configuration that only controls irradiation and non-irradiation of ultraviolet light without strictly controlling the ultraviolet light source 5. The entire image can be erased and rewritten.

  Even if the display body 3 is enlarged, it is not necessary to build an active matrix circuit in the display body 3, so that an inexpensive large screen display system can be realized. Furthermore, even if the display body 3 itself has one specification, the resolution, size, shape, number of pixels, etc. of the screen can be freely defined depending on which projector 4 is used.

  Further, since the UV cut filter 6 is provided on the viewing side of the display body 3 and the ultraviolet light source 5, when external light such as sunlight enters the display body 3, an image is generated by an ultraviolet component contained in the external light. Can be prevented from being erased. Further, it is possible to prevent the ultraviolet light emitted from the ultraviolet light source 5 from leaking to the viewer side. Moreover, since the titanium oxide film | membrane which carry | supported the silver nanoparticle is used as the photochromic material which comprises the reaction layer 8, said two reaction can be expressed reliably.

  In the above-described embodiment, an example in which the projector 4 including a white light source such as an ultrahigh pressure mercury lamp is used has been described. However, instead of this configuration, a projector using a visible light laser as a light source may be used. In that case, a projector that forms an image by modulating laser light emitted from a visible light laser by a light valve may be used, or the laser light itself may be modulated and modulated by a mirror such as a galvano mirror or a MEMS scanner. You may use the projector which scans a laser beam on a display body and forms an image. When using a laser light source, since the laser light has a narrow wavelength region compared to the light from the lamp, it is possible to generate silver nanoparticles that reflect light of a wavelength corresponding to the laser light even with a small amount of light, A display with excellent responsiveness can be realized.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the display system of this embodiment is substantially the same as that of the first embodiment. In the first embodiment, an ultraviolet light source is provided outside the projector, and the entire surface of the display body is irradiated with ultraviolet light. The present embodiment is different in that an ultraviolet light source is built in the projector and ultraviolet light is selectively irradiated onto a part of the display body.
FIG. 4 is a side view showing a schematic configuration of the display system of the present embodiment. FIGS. 5A to 5C are diagrams for explaining a procedure from image display to image erasure of the display system.

  In the display system 11 of this embodiment, as shown in FIG. 4, a white light source 9 (visible light source) and an ultraviolet light source 5 are incorporated in the projector 14. Various conventional configurations can be used for the portion relating to the modulation of visible light emitted from the white light source 9. The ultraviolet light emitted from the ultraviolet light source 5 is modulated using a light valve such as a digital micromirror (DMD), and the modulated ultraviolet light is irradiated onto a part of the display body 3 and an irradiation region is arbitrarily selected. can do. In the case of a liquid crystal light valve, resistance to ultraviolet light is small and modulation of ultraviolet light is difficult, but in the case of a light valve such as DMD, resistance to ultraviolet light is large and modulation of ultraviolet light is possible. Therefore, it is desirable to use a light valve such as DMD in this embodiment. In this case, as shown in FIG. 3, since the modulation of visible light and the modulation of ultraviolet light are performed in different periods, both the modulation of visible light and the modulation of ultraviolet light can be performed with one DMD light valve. .

  When displaying an image, as shown in FIG. 5A, visible light is emitted from the projector 14, and arbitrary images A and B are projected on the display 3. Then, as shown in FIG. 5B, even when the projector 14 is turned off and projection is stopped, the images A and B are still displayed on the display 3. The above is the same as in the first embodiment. Thereafter, the method for erasing the image is different from that of the first embodiment. As shown in FIG. 5C, the ultraviolet ray is generated based on the image signal used when projecting the images A and B shown in FIG. By modulating light and irradiating only a display area of a specific image, for example, the image B, of the images A and B, only the image B can be selectively erased. When rewriting the image, the image may be projected again from the projector 4 onto the display body.

  Also in the display system 11 of the present embodiment, an inexpensive large screen display system that can obtain an image with excellent contrast, can reduce power consumption, and can realize a system with a low environmental load can be realized. The same effects as in the first embodiment, such as the ability to freely define the shape, the number of pixels, etc., can be obtained. In the case of the present embodiment, only a specific image in the entire image can be erased and rewritten, so that the expressive power of the image can be increased.

  In the above embodiment, an example in which ultraviolet light is modulated by a light valve such as DMD has been shown, but instead of this configuration, ultraviolet light is modulated and ultraviolet light is displayed on the display 3 by a mirror such as a galvano mirror or a MEMS scanner. Alternatively, only a part of the image may be erased by scanning. Further, it is not always necessary to irradiate the ultraviolet light based on the image signal, and a configuration in which a predetermined region of the entire region of the display body is always erased regardless of the content of the image may be employed. For example, when considering application to advertising, signage, etc., the display area and the text display area are fixed on the display body, and the display of either the picture or text is left as it is, and the other It is also possible to rewrite only the display.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
In the first and second embodiments, an example of a front type display system is shown, but in this embodiment, an example of a rear type display system is shown.
FIG. 6 is a side view showing a schematic configuration of the display system of the present embodiment.

  In the display system 21 of the present embodiment, as shown in FIG. 6, the projector 4 including the white light source 9 and the ultraviolet light source 5 are arranged on the back side of the display body 23. The reaction layer 8 made of the photochromic material described in the first embodiment is formed on the back side of the support plate 7 constituting the display body 23. Further, a UV cut layer 26 (ultraviolet light blocking layer) is formed on the front surface side of the support plate 7.

  Also in the display system 21 of the present embodiment, an inexpensive large screen display system that can obtain an image with excellent contrast, can reduce power consumption, and can realize a system with a low environmental load can be realized. The same effects as in the first embodiment, such as the ability to freely define the shape, the number of pixels, etc., can be obtained.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the first and second embodiments, the display body is disposed so that the surface on which the reaction layer is formed faces the viewing side. On the contrary, the surface on the side on which the reaction layer is formed. You may arrange | position a display body so that may face a back side. Similarly, in the third embodiment, the display body is arranged so that the surface on which the reaction layer is formed faces the back side. On the contrary, the surface on which the reaction layer is formed is the front surface. The display body may be arranged to face the side. However, in that case, it is necessary to laminate a UV cut layer on the reaction layer. In addition, the specific configuration of each part of the display system can be changed as appropriate.

It is a side view which shows the display system of 1st Embodiment of this invention. It is a figure for demonstrating the procedure of the image display of this display system. It is a figure for demonstrating the drive method of this display system. It is a side view which shows the display system of 2nd Embodiment of this invention. It is a figure for demonstrating the procedure of the image display of this display system. It is a side view which shows the display system of 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,11,21 ... Display system, 3,23 ... Display body, 4,14 ... Projector (projection apparatus), 5 ... Ultraviolet light source, 6 ... UV cut filter (ultraviolet light blocking layer), 8 ... Reaction layer, 9 ... White light source (visible light source), 26... UV cut layer (ultraviolet light blocking layer).

Claims (6)

It has absorptivity with respect to light in almost all visible wavelength regions in a state where it is not irradiated with visible light, and the first absorbs light with a specific visible wavelength region when irradiated with the visible light. A display body comprising a reaction layer made of a photochromic material in which a reaction occurs and a second reaction occurs in which absorption of light in the visible wavelength region occurs when ultraviolet light is irradiated after the first reaction occurs; ,
A visible light source that emits the visible light; a projection device that projects the visible light from the visible light source onto the display body and writes an image on the reaction layer;
An ultraviolet light source that irradiates the reaction layer with the ultraviolet light.   The display system according to claim 1, wherein the ultraviolet light source can irradiate the entire region of the reaction layer with the ultraviolet light.   The display system according to claim 1, wherein the ultraviolet light source can selectively irradiate only the specific region of the reaction layer with the ultraviolet light.   The display system according to claim 3, wherein the ultraviolet light source irradiates the ultraviolet light only to a region where a specific image is displayed based on an image signal supplied to the projection device.   The display system according to claim 1, wherein an ultraviolet light blocking layer that blocks the ultraviolet light is provided on a viewing side of the display body and the ultraviolet light source.   6. The display system according to claim 1, wherein a titanium oxide film carrying silver particles is used as a photochromic material constituting the reaction layer.

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