JP2005114869A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a display having a depth feel and imparting an impression that an image stands out in a space by displaying the image in a transparent body. <P>SOLUTION: An optical device is formed by laminating ten or more thin optical elements with interposing transparent resin, each optical element is individually driven by a driving circuit, image light is projected from an image projector which is separately arranged, and the light transmission state and light diffusion state of the optical element are controlled, then, a display device for performing a stereoscopic display is attained. The tensile elastic modulus of the transparent resin is ≤120MPa. Also, the image is displayed so that display elements constituting the display come and go between a plurality of optical elements. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a display device that performs display by projecting image light.

  At present, CRT, PDP, and liquid crystal display (LCD) are widely used as display devices. It is used in TV display devices, personal computer display devices, display terminals for industrial use and consumer use, and the like.

  However, the display unit itself of the display device is not transparent. The presence of the display device itself may be annoying for the user when not in use and at the time of use. It may also give the user a feeling of pressure. For this reason, a display device that gives the user a feeling of opening is desired. Furthermore, a display device that can see the background side of the display unit is also desired. There is a strong demand for thinning and flattening the display portion, and research for improving the performance of the display device is being conducted.

  For example, there is a head-up display for automobiles (conventional example 1). In this method, image light is projected from an image projector onto a half mirror or hologram arranged on the windshield, and the image light is reflected. It can be shown to the user as if the image is on the windshield. In this method, the half mirror or the hologram is not completely transparent, and the presence of the display unit is easily observed when not displayed.

  There is also a display system using a hologram optical element (conventional example 2). It is used to produce storefronts such as show windows. In this configuration, light is incident on the hologram optical element from the projector at a specific angle. The hologram optical element scatters the light to display an image. In this method, since light is not scattered with respect to light incident from other than a specific angle, high contrast display can be realized. However, since the scattering characteristics are angle-dependent, the viewing angle is narrow, and an image cannot be seen when viewed from an oblique direction.

  Patent Document 1 discloses an image display device that uses a single optical element as a transparent body (Conventional Example 3). An image is displayed by switching between the light transmission state and the light scattering state of the optical element. In Conventional Example 3, the optical element is opaque while an image is displayed on the optical element, and a state where the image exists in the background cannot be realized.

  On the other hand, Patent Document 2 discloses a technique for realizing a state in which an image exists in the background (Conventional Example 4). In this conventional example 4, only a certain part of the image is scattered and used as an optical element. However, when the image is viewed, the background behind the image cannot be seen.

  Patent Document 3 discloses the use of a plurality of optical elements (conventional example 5). In this conventional example 5, the configuration of the device that allows the observer to see the background is not shown at all.

  Furthermore, Patent Document 4 discloses a method of drawing a stereoscopic image on an optical element composed of a plurality of liquid crystal cells (Conventional Example 6). Also in this prior art example 6, the structure which enables an observer to see a background is not shown at all.

Japanese Utility Model Publication No. 04-114088 (Summary, Fig. 1)

JP 05-191726 A (paragraph number 0010, FIG. 1)

Japanese Patent Laid-Open No. 05-307185 (paragraph numbers 0020 and 0021, FIGS. 4 and 5)

Japanese Patent Laid-Open No. 2002-139700 (paragraph numbers 0019 to 0021, FIGS. 1 and 2)

  The present invention seeks to obtain a display device capable of displaying an image on a transparent body and displaying an image with a sense of depth.

  In addition, it is intended to provide a new technology capable of realizing a display that gives an impression that an image is floating in a space.

  That is, according to the first aspect of the present invention, an optical element in which an electro-optic modulation layer is sandwiched between a pair of substrates with electrodes and a drive circuit that drives the optical element are provided. A display device capable of transferring two or more optical states including a light transmission state and a light scattering state according to a signal, wherein a plurality of optical elements are arranged, and a transparent substance is provided between outer surfaces of adjacent optical elements. The optical state of each optical element is controlled by a drive circuit, and the transmittance of light rays from the outer surface of the optical element located on the foremost surface to the outer surface of the optical element located on the rearmost surface is 30% or more, Furthermore, an image projector is provided, image light is projected from the image projector toward the outer surface of the optical element on the back surface, and the display is visually recognized from the outer surface side of the optical element on the front surface. Provide That.

  Aspect 2 provides the display device according to aspect 1, wherein the number of optical elements is ten or more.

  Aspect 3 provides the display device according to aspect 1 or 2, wherein the tensile modulus of the transparent material is 120 MPa or less.

  Aspect 4 provides the display device according to aspects 1, 2 or 3, wherein the display is performed such that at least one display element constituting the display goes back and forth between the plurality of optical elements.

  Aspect 5 provides the display device according to aspect 4, wherein display is performed in which the display element moves within the screen.

  Aspect 6 provides the display device according to aspects 1, 2, 3, 4 or 5, wherein the difference between the refractive index of the transparent substance and the refractive index of the material constituting the substrate is within 0.15.

  Aspect 7 provides the display device according to aspects 1, 2, 3, 4, 5 or 6, wherein the display element represents a living thing.

  Aspect 8 is an aspect in which the distance between two optical elements arranged adjacent to each other is 0.4 to 200 mm, and the brightness of an image projected on the two optical elements is made different from each other. A display device according to any one of the above is provided.

  Aspect 9 is the display device according to any one of aspects 1 to 8, wherein the liquid crystal of the liquid crystal layer and the cured resin are formed by a photopolymerization curing method.

  Aspect 10 is the display device according to any one of aspects 1 to 9, wherein the main part of the peripheral portion of the display device is transparent.

  Aspect 11 is the display device according to any one of aspects 1 to 10, wherein the thickness of the display device is 5 cm or more.

  Aspect 12 is the display device according to any one of aspects 1 to 11, which is transparent except for a connection portion with an external circuit.

  Aspect 13 provides the display device according to any one of aspects 1 to 12, wherein the transmittance when no voltage is applied is 80% or more.

  According to the present invention, when not in use, it is transparent, its presence itself is less obtrusive and does not give a feeling of pressure, has a feeling of openness, and can provide a transparent display.

  In addition, it is possible to realize an image that gives the impression that a transparent image is floating in the space.

  Embodiments of the present invention will be described below with reference to the drawings, examples and the like. In addition, these figures, Examples, etc. and description illustrate the present invention, and do not limit the scope of the present invention. It goes without saying that other embodiments may belong to the present invention as long as they match the gist of the present invention. In the figure, the same reference numerals are assigned to the same elements.

  The optical element used in the present invention is one in which the liquid crystal layer can repeatedly take a light transmission state and a light scattering state. The light transmission state and the light scattering state are states applied to visible light. As for the light transmission state, when the image is not viewed with the optical element, the optical element is transparent and gives a sense of openness. When viewing the image projected onto the optical element, look at the background side of the optical element. It is preferable that the light transmittance is high so as to give a transparent feeling.

  However, it can be appropriately selected according to the required degree of openness or transparency. The light scattering state is not particularly limited, but when the image is projected onto the optical element, the image is observed from the back side of the optical element, that is, the back side relative to the image projection side of the optical element. Therefore, a higher forward scattering ratio is preferable, and a higher back scattering ratio is preferable for observing the image from the image projection side of the optical element.

  The switching between the light transmission state and the light scattering state is performed by the optical element including a liquid crystal layer and a transparent pair of substrates with electrodes sandwiching the liquid crystal layer. For example, when a voltage is applied between the transparent electrodes, the liquid crystal layer Can be realized by taking a light scattering state and allowing the liquid crystal layer to take a light transmitting state when voltage application between the transparent electrodes is stopped.

  As the liquid crystal layer, a composite made of a liquid crystal and a cured resin can be used. A liquid crystal layer comprising a liquid crystal and a curable resin is obtained by sandwiching a composition containing a liquid crystal and a curable compound between a pair of transparent substrates with electrodes, and using such means as heat, ultraviolet rays, and electron beams. Can be cured to form a liquid crystal / cured resin composite layer. Alternatively, the liquid crystal and the cured resin of the liquid crystal layer are formed by, for example, a photopolymerization curing method.

  The curable resin according to the present invention may be any known resin as long as it has transparency and does not contradict the spirit of the present invention, but the liquid crystal is such that only the liquid crystal responds substantially when a voltage is applied. In order to realize a liquid crystal layer having high-speed response, it is preferable that the resin and the cured resin have a separated structure.

  As a curable compound for forming a curable resin having such a structure, by selecting a curable compound that can be dissolved in liquid crystal, it becomes possible to control the alignment state of the mixture when uncured, and the curable resin is cured. When this is done, it becomes possible to maintain high transparency. In the present invention, it goes without saying that the image includes character information. Furthermore, an image whose display content is changed with time, a moving image such as skipping frames, a normal moving image, and the like are included.

  Further, if the substrate is in contact with the liquid crystal layer and the pretilt angle of the liquid crystal molecules is set to 60 ° or more with respect to the substrate surface, alignment defects can be reduced, and transparency Is preferable. At this time, the rubbing process may or may not be performed. The pretilt angle is more preferably 70 degrees or more. The pretilt angle is defined as 90 degrees in the direction perpendicular to the substrate surface.

  Examples of the curable compound include the compound of formula 1 and the compound of formula 2.

A ¹ —O— (R ¹ ) _m —O—Z—O— (R ² ) _n O—A ² (1)
_{^{A 3 - (OR 3) o}} -O-Z'-O- (R 4 O) p -A 4 ··· (2)

Here, A ¹ , A ² , A ³ and A ⁴ are each independently an acryloyl group, a methacryloyl group, a glycidyl group or an allyl group, and R ¹ , R ² , R ³ and R ⁴ are each independently , An alkylene group having 2 to 6 carbon atoms, Z and Z ′ are each independently a divalent mesogen structure part, and m, n, o, and p are each independently an integer of 1 to 10. is there.

High molecular mobility including R ¹ , R ² , R ³ , R ⁴ between the mesogenic structures Z, Z ′ of Formula 1 and Formula 2 and the cured sites A ¹ , A ² , A ³ , A ⁴ By introducing an oxyalkylene structure, the molecular mobility of the cured site in the curing process can be improved during curing, and sufficient curing can be achieved in a short time.

The curing sites A ¹ , A ² , A ³ , and A ^{4 in} Formulas 1 and 2 may be any of the functional groups that can be photocured or thermally cured. An acryloyl group and a methacryloyl group suitable for photocuring are preferable because they can be controlled.

The number of carbon atoms of R ¹ , R ² , R ³ and R ⁴ in formulas 1 and 2 is preferably 1 to 6 from the viewpoint of molecular mobility, and an ethylene group having 2 carbon atoms and a propylene group having 3 carbon atoms Further preferred.

  Examples of the mesogen structure parts Z and Z ′ in the formulas 1 and 2 include polyphenylene groups in which 1,4-phenylene groups are linked. The 1,4-phenylene group may be partially or wholly substituted with 1,4-cyclohexylene group. In addition, some or all of the hydrogen atoms of these 1,4-phenylene groups and substituted 1,4-cyclohexylene groups may be alkyl groups having 1 to 2 carbon atoms, halogen atoms, carboxyl groups, alkoxycarbonyl groups, etc. It may be substituted with a substituent.

  Preferable mesogen structure parts Z and Z ′ include a biphenylene group in which two 1,4-phenylene groups are connected (hereinafter, a biphenylene group in which two 1,4-phenylene groups are connected is also referred to as a 4,4-biphenylene group). ) Three linked terphenylene groups and those in which 1 to 4 of these hydrogen atoms are substituted with an alkyl group having 1 to 2 carbon atoms, a fluorine atom, a chlorine atom or a carboxyl group. Most preferred is a 4,4-biphenylene group having no substituent. All the bonds between 1,4-phenylene groups or 1,4-cyclohexylene groups constituting the mesogenic structure may be single bonds or any of the following bonds.

  M, n, o, and p in Formula 1 and Formula 2 are each independently preferably 1 to 10, and more preferably 1 to 4. If it is too large, the compatibility with the liquid crystal is lowered, and the transparency of the cured optical element is lowered.

  Examples of curable compounds that can be used in the present invention are shown below.

  The composition containing the liquid crystal and the curable compound may contain a plurality of curable compounds including the curable compounds represented by the above formulas (1) and (2). For example, when this composition contains a plurality of curable compounds having different m, n, o, and p in formulas 1 and 2, compatibility with the liquid crystal may be improved.

  The composition containing a liquid crystal and a curable compound may contain a curing catalyst. In the case of photocuring, a photopolymerization initiator generally used for photocuring such as benzoin ether, acetophenone, and phosphine oxide can be used. In the case of thermosetting, a curing catalyst such as peroxide, thiol, amine, or acid anhydride can be used depending on the type of curing site, and if necessary, curing aids such as amines can also be used. Can be used.

  The content of the curing catalyst is preferably 20% by weight or less of the curable compound to be contained, and more preferably 1 to 10% by weight when a high molecular weight or high specific resistance of the cured resin is required after curing.

  As a treatment method for aligning liquid crystal molecules so that the pretilt angle is 60 degrees or more with respect to the substrate surface, there is a method using a vertical alignment agent. The vertical alignment agent is, for example, a method using a surfactant, a method of treating the substrate surface with a silane coupling agent containing an alkyl group or a fluoroalkyl group, or SE1211 manufactured by Nissan Chemical Industries, or JALS- manufactured by JSR. There is a method using a commercially available vertical alignment agent such as 682-R3. In order to create a state in which the liquid crystal molecules are tilted in an arbitrary direction from the vertical alignment state, any known method may be adopted. The vertical alignment agent may be rubbed. Alternatively, a method may be employed in which a slit is provided in the electrode or a triangular prism is disposed on the electrode so that the voltage is applied obliquely to the substrate.

  The liquid crystal according to the present invention can be appropriately selected from known liquid crystals, but those having a negative dielectric anisotropy are preferably used. In order to reduce the drive voltage, it is preferable that the dielectric anisotropy is large.

  As the substrate used for the optical element, any known substrate can be used as long as transparency can be secured. A glass substrate can be used. It may be plastic or film. Further, the optical element surface does not need to be planar, and may be a bent optical element.

  As an electrode provided on the substrate, a transparent electrode material of metal oxide such as ITO (indium oxide-tin oxide) can be used.

  A combination of alignment directions of the pair of alignment-treated substrates may be either parallel or orthogonal and may be arranged at an appropriate angle. A known function of aligning the liquid crystal on the electrode surface can be provided by providing a resin thin film on the electrode surface of the electrode-attached substrate and rubbing the resin thin film.

  The thickness of the liquid crystal layer between the two substrates can be defined by a spacer or the like. The interval is preferably 1 to 50 μm, and more preferably 3 to 30 μm. If the thickness of the liquid crystal layer is too narrow, the contrast is lowered, and if it is too large, the tendency of the drive voltage to increase increases, which is often not preferable.

  FIG. 1 is a schematic cross-sectional view of an example of an optical element having such a structure. In FIG. 1, transparent electrodes 23 and 24 are provided on opposing surfaces of a pair of glass substrates 21 and 22. Further, an alignment film is provided on the inner side (not shown). In some cases, this alignment film is not provided. A liquid crystal layer 27 having a thickness defined by a spacer (not shown) is sandwiched between the alignment films. The liquid crystal layer 27 contains a cured resin.

  In general, the liquid crystal scattering / transmission mode is configured to take a light transmission state when a voltage is applied between the electrodes and to take a light scattering state when the voltage application is stopped. Alternatively, the light scattering state can be taken when a voltage is applied, and the light transmitting state can be taken when the voltage application is stopped. In order to realize an optical element that is transparent when the power is turned off and the image display device is not used, and the presence of the optical element is unobtrusive or less squeezed and has a sense of openness, the latter These conditions are preferred. For this reason, the present specification mainly describes an optical element structure configured to take a light scattering state when a voltage is applied and to take a light transmission state when the voltage application is stopped. However, in the present invention, a liquid crystal layer having the opposite operation mode can also be used.

  The liquid crystal layer of the optical element manufactured as described above often has a very high response speed of 3 ms or less between the light transmission state and the light scattering state. In addition, compared with the conventional scattering transmission mode, it is possible to obtain a very good transmission state even when viewed from an oblique direction. For example, when the thermosetting composition having the composition exemplified above is used, it is possible to have almost no haze even when viewed at an angle of 40 degrees from the vertical. That is, the viewing angle dependency of the light transmission state is good, and it can be made to look like glass.

  A commercially available projector or the like can be used as the image projector. For example, a projector (model number: ELP-50) manufactured by Epson Corporation can be exemplified. Also, a liquid crystal projector using a normal nematic liquid crystal, a projector using a digital micromirror device (DMD) manufactured by Texas Instruments, a projector using LCOS (Liquid Crystal On Silicon) or a ferroelectric liquid crystal can be used. . In the case of a still image, a slide projector may be used.

  The general configuration of an image projector has three systems: a lamp system, an image display system, and a projection lens system. The lamp system is preferably a uniform parallel light source and may be combined with an integrator. When the image display system uses polarized light such as liquid crystal, it may be aligned with linearly polarized light using a polarization conversion element. Examples of the image display system include a liquid crystal panel, DMD, and LCOS. To achieve full color, the light source is separated into three primary colors and displayed on three liquid crystal panels, the method using a single liquid crystal panel with a color filter, and the field sequential color by sequentially switching the color of the light source. There are also methods. The projection lens system may be optimized according to the size of the optical element and the distance between the image projector and the optical element.

  It is preferable to reduce the overall configuration because it does not take up space. For example, a mini projector with a compact design is preferable. Since the mini projector eliminates the need for a large space, it is convenient for in-vehicle use (instrument panel, car navigation system, audio, etc.), office use (register, etc.), amusement use (pachinko, pachislot, game machine, etc.).

  As a light source of the image projector, a metal halide lamp, an ultrahigh pressure mercury lamp, a halogen lamp, a xenon lamp, an LED light source, or the like can be used. When a color image is desired to be projected, a field sequential color method may be used. A laser drawing apparatus may be used in addition to the projector.

  The image projector is preferably set to project only when the liquid crystal layer of the optical element is in a light scattering state, so that the projection light transmitted through the optical element does not escape to the viewer side. Note that a plurality of optical elements according to the present invention are used, and for example, they are stacked to constitute an optical device integrated as a whole. A transparent material having high transparency is disposed between adjacent optical elements. The image projector is configured to project an image onto the optical element in the light scattering state, and when there is a time when the liquid crystal layer of all the optical elements is in the light transmissive state, no image is projected. It is preferable that it is such.

  If the image is not projected when the liquid crystal layers of all the optical elements are in the light-transmitting state, the projection light transmitted through the optical elements does not escape to the viewer side. In addition, if the image projector projects an image onto the optical element in the light scattering state, the timing of the light scattering state of the liquid crystal layer of the optical element and the projection of the image can be well synchronized.

  It is preferable that the time zones in which the liquid crystal layers of all the optical elements are in the light transmission state overlap. This is because it is possible to see the background behind and the image on the optical element at the same time. Here, in the present invention, “the background scene and the image on the optical element can be viewed simultaneously” means that the background scene can be viewed through the image itself and that the image on the optical element is viewed. For a portion of the optical element where an image is not projected, it means that the background can be seen and / or either. In the former case, it is possible to give the impression that the scenery behind and the image on the optical element are superimposed and viewed simultaneously. In the latter case, it is possible to give the impression that the image is floating in the air.

  An example of a configuration capable of realizing this will be described with reference to FIG. As illustrated in FIG. 2, a plurality of optical elements 1 and 1 ′ are disposed, and a transparent material 17 is disposed between the optical elements. Although two optical elements 1 and 1 'are shown in FIG. 2, the number of optical elements may be 10 or more. The tensile modulus of the transparent material 17 is 120 MPa or less. The tensile elastic modulus of the transparent substance 17 is more preferably 30 MPa or less, and particularly preferably 5 MPa or less. By using a transparent material having a low elastic modulus, it is possible to ensure impact resistance against external force. Examples of such a transparent substance 17 include a silicone resin, a urethane resin, and an acrylic resin. The difference between the refractive index of the transparent substance 17 and the refractive index of the material constituting the substrate is preferably within 0.15. Further, when a plurality of optical elements are arranged, it is preferable that the transmittance of light rays from the outer surface of the optical element positioned at the forefront to the outer surface of the optical element positioned at the rearmost is 30% or more. Furthermore, the transmittance when no voltage is applied is preferably 80% or more. Further, the thickness of the display device is, for example, 5 cm or more. The state of the optical elements 1 and 1 ′ is controlled by a drive circuit (not shown in FIG. 2).

  In the example of FIG. 2, the optical device 10 is placed between the image projector 2 and the observer. In this case, if the shutter 3 is disposed between the image projector 2 and the optical device 10 and the shutter 3 is allowed to pass light only when the electro-optic modulation layer of the optical element is in the light scattering state, the image projector Is projected onto the optical element only when the liquid crystal layer of the optical element is in a light scattering state.

  That is, the timing of passage and blocking of light in the shutter may be synchronized with the driving timing at which the liquid crystal layer of the optical element takes the light transmission state and the light scattering state. In this way, the observer 4 can see the background 5 in the light transmission state and can see the image on the optical element 1 in the light scattering state. In this case, as a result of switching between the light transmission state and the light scattering state, it is possible to simultaneously view the background 5 and the image on the optical element 1 as a synthesized afterimage. In the figure, the blindfold plate 6 is installed as necessary so that the image projector does not directly enter the observer's field of view.

  The repetition frequency of switching between the light transmission state and the light scattering state is related to the flickering of the image on the optical element. That is, it is effective to increase the repetition frequency so that the observer does not feel the flicker of the image.

  In addition, the temporal ratio between the light transmission state and the light scattering state is related to the ratio of making the background scene or the image on the optical element easier to see. That is, when the time ratio of the light transmission state is large, the background behind the image can be clearly seen, but the image on the optical element cannot be seen or is difficult to see. Then, as the time ratio of the light transmission state is gradually reduced, the image on the optical element starts to appear roughly and gradually becomes clearer. At the same time, the landscape behind it becomes clearer at first, but disappears at the end.

  Therefore, by appropriately setting the ratio of the time during which the liquid crystal layer of the optical element is in the light scattering state and the time during which the optical element is in the light transmitting state, the observer can view the image on the optical element and the scenery behind the optical element. Can be recognized at the same time. Including the case where a plurality of optical elements are used, the total time during which at least one of the optical elements is in the light scattering state within one frame and the time during which the liquid crystal layers of all the optical elements are in the light transmitting state, This ratio can be set so that the observer can simultaneously recognize the image on the optical element and the scenery behind the optical element. It should be noted that if the image on the optical element can be seen clearly but it is difficult to see the background, it is effective to change the brightness of the projected image.

  The shutter may be disposed between the image projector and the optical element, may be attached to the image projector, or may constitute a part of the image projector.

  The shutter is required to have high speed response. For this purpose, a liquid crystal shutter or the like can be used in addition to a general mechanical shutter. For example, a ferroelectric liquid crystal shutter or a shutter using a transmission / scattering type liquid crystal mode may be used. In the case of using a polarizing plate as the shutter, it is preferable that the polarization of light emitted from the image projector of the projector is aligned with the transmission axis of the light incident side polarizing plate of the shutter because the light use efficiency is increased.

  Instead of using the shutter, the projection timing of the image from the image projector may be directly synchronized with the driving timing at which the liquid crystal layer of the optical element takes the light transmission state and the light scattering state. In the case of a liquid crystal projector or a DMD projector, the light source may be turned on / off instead of the shutter. In this case, an LED capable of high-speed switching may be used as the light source.

  The drive timing at which the liquid crystal layer of the optical element takes a light transmission state and a light scattering state with respect to incident light will be described with reference to FIG. In FIG. 3, for example, an electric field is applied between the electrodes of the optical element to apply an electric field to the liquid crystal layer to change from a light transmission state to a light scattering state, and an image from an image projector is projected in synchronization therewith. In addition, the voltage application between the electrodes of the optical element is stopped, the electric field of the liquid crystal layer is removed, the liquid crystal layer of the optical element is changed from the light scattering state to the light transmitting state, and the projection from the image projector is performed in synchronization therewith. Turn off. By repeating this operation, an image is projected only when the liquid crystal layer of the optical element is in a light scattering state, and the observer can see the image scattered by the optical element.

  Therefore, by repeating the above light transmission state and light scattering state, the observer can simultaneously recognize the two states of the image on the optical element and the scenery behind the optical element.

  When the optical element is sufficiently scattering, the light is scattered in all directions so that the observer can see the image projector side, the opposite side of the image projector and the other side of the optical element. It can be seen from various directions such as an oblique direction. However, when the liquid crystal layer according to the present invention is used, the ratio of the backscattering of the light beam (the ratio of the light beam scattered to the image projector side with respect to the optical element) is the forward scattering ratio (the image projector with respect to the optical element). In many cases, the image projector is disposed on the side opposite to the observer with respect to the optical element.

In the image display device according to the present invention, the repetition frequency of the frame consisting of the minimum unit of repetition of the light transmission state and the light scattering state is within a range in which the observer does not feel flicker of the image on the optical element. The total time T ₁ during which the liquid crystal layer of at least one of the optical elements is in the light scattering state and the time T ₂ during which the liquid crystal layers of all the optical elements are in the light transmission state within one frame. It is necessary that the ratio can be set so that the observer can simultaneously recognize the image on the optical element and the scene behind the optical element.

There are a light scattering state and a light transmission state of the liquid crystal layer of the optical element during one frame, and when an image is projected onto the optical element in the light scattering state, for the observer, the time T ₁ for viewing the image and the optical element There will be a time T ₂ for viewing the background, but if you set such a condition, you can view the image and the background at the same time without worrying about flickering of the image. Because it can.

  In general, if the repetition frequency of one frame is 30 Hz or more, the flickering of the image does not matter due to the afterimage action. If the repetition frequency of one frame is 50 Hz or more, flicker is not a concern at all. More preferably, it is 70 Hz or more. The upper limit is not particularly limited, but if it exceeds 1 kHz, the optical element cannot respond completely and the amount of current consumption increases, so 1 kHz or less is preferable.

Here, the “frame” is composed of the minimum unit of repetition of the combination of the light transmission state and the light scattering state, and in the case of FIG. 3, is the sum of T ₁ and T ₂ .

There may be a plurality of optical elements according to the present invention. When there are a plurality of optical elements, the total time T ₁ during which the liquid crystal layer of at least one of the optical elements is in the light scattering state and the time T during which the liquid crystal layers of all the optical elements are in the light transmission state within one frame. ₂ is important to satisfy T ₁ / (T ₁ + T ₂ ) ≦ 0.8. This is because if T ₁ / (T ₁ + T ₂ ) ≦ 0.8, the scenery behind the optical element can be seen simultaneously. There is no particular limitation on the lower limit of T ₁ / (T ₁ + T ₂ ), but if it is too short, it may be difficult to see the image projected on the optical element. Except when subliminal images are used, it is often preferable that 0.01 <T ₁ / (T ₁ + T ₂ ).

The ratio of T ₁ / (T ₁ + T ₂ ) varies depending on whether priority is given to viewing the image projected on the optical element or priority to seeing the scenery behind the optical element. For example, in an application such as an in-vehicle head-up display, priority is given to viewing the scenery behind the optical element. Therefore, T ₁ / which is a condition for increasing transparency and making the scenery behind the viewing easier to see. (T ₁ + T ₂ ) <0.5 is preferred. The ratio may be changed depending on the situation.

For example, T ₁ / (T ₁ + T ₂ ) = 0.7 when the car is stopped, and T ₁ / (T ₁ + T ₂ ) = 0.3 when the car is moving. May also be useful. When the amount of light from the image projector is large, T ₁ / (T ₁ + T ₂ ) = 0.1 may be set. In this case, the time during which the optical element is in the light-scattering state is shortened, but since the amount of light is large, the observer can recognize the image and the background behind the scene looks almost normal. Looks like it's floating.

  In the case where there are a plurality of optical elements capable of repeatedly taking the light transmission state and the light scattering state, it is preferable to use these in an overlapping manner. The degree of superposition and the distance between optical elements can be arbitrarily selected according to the application. For example, when it is desired to give an impression that the space is moved greatly in the depth direction as viewed from the observer, it is preferable to increase the distance between the optical elements.

  In this case, the drive timing at which the liquid crystal layer of the optical element takes the light transmitting state and the light scattering state will be described with reference to FIG. When there are three or more optical elements, it can be considered according to this.

  In the present invention, not only one image projector but also a plurality of image projectors can be installed and a plurality of projection lights can be used simultaneously.

  In the present invention, the drive timing at which the liquid crystal layer of the optical element takes the light transmitting state and the light scattering state can be as shown in FIG. 4, for example. The display of the light transmission state and the light scattering state in FIG. 4 is the same as in FIG. At this drive timing, when the liquid crystal layer of the optical element 1 is in the light scattering state, there is only a case where the liquid crystal layer of the optical element 1 ′ is in the light transmission state, and when the liquid crystal layer of the optical element 1 is in the light transmission state, There are cases where the liquid crystal layer of the element 1 ′ is in a light scattering state and in a light transmission state.

  When the liquid crystal layer of the optical element 1 is in the light scattering state, the liquid crystal layer of the optical element 1 ′ is in the light transmissive state, so that an image is projected onto the optical element 1 and not onto the optical element 1 ′. Can do. In this case, the observer views the image on the optical element 1 through the optical element 1 '.

  When the liquid crystal layer of the optical element 1 is in a light-transmitting state and the liquid crystal layer of the optical element 1 ′ is in a light-scattering state, an image can be projected through the optical element 1 onto the optical element 1 ′. Then, the observer sees the image on the optical element 1 '.

  Further, when the liquid crystal layer of the optical element 1 is in a light-transmitting state, if the liquid crystal layer of the optical element 1 ′ is in a light-transmitting state, the image is not projected on the optical element 1 or the optical element 1 ′, and is observed. A person can see the scenery 5 on the side of the image projectors 2 and 2 ′ through the optical elements 1 and 1 ′.

  Therefore, by repeating the driving timing for taking the light transmission state and the light scattering state, the observer can obtain the image on the optical element 1, the image on the optical element 1 ′, and the scenery 5 behind the optical element. These three states can be recognized simultaneously. When these images appear to overlap, one is not hidden behind the other, but both are visible at the same time.

The image on the optical element 1 and the image on the optical element 1 ′ may be projected from two image projectors as described above, but may be projected from one image projector. . However, in this case, in order to make the image on the optical element clear, it may be necessary to switch the focus of the image projector according to the distance between the optical elements. When the same image is displayed by the optical element 1 and the optical element 1 ′, it is possible to obtain an image in which the image goes back and forth between the optical element 1 and the optical element 1 ′. T ₁₁ / T ₁₂ and T ₂₁ / T _22, which are time ratios between the light scattering state and the light transmission state, may be the same or different.

Further, the start time of T ₂₁ may not be immediately after T ₁₁ as shown in FIG. An example is shown in FIG. As shown in FIG. 4, even if T ₁₁ and T ₂₂ overlap in time, T ₂₁ and T ₁₂ overlap in time, and T ₁₂ and T ₂₂ overlap in time. While good, duplication of T ₁₁ and T ₂₁ should often be avoided. This is because when the optical elements overlap, an image may not be projected onto the optical element to be projected.

  The frames are usually repeated at the same cycle, but may be partially different depending on the case.

However, in any case, the timing of the passage and blocking of the light in the shutters 3 and 3 ′ is the light transmission state and the light scattering state in the optical elements 1 and 1 ′, respectively, as shown in FIGS. Should be synchronized with T ₁₁ / T ₁₂ and T ₂₁ / T ₂₂ which are drive timings for

  The same can be achieved by arranging three or more optical elements in an overlapping manner. Various expressions are possible in which the image moves back and forth, left and right, up and down, and diagonally. Further, when the number of optical elements exhibiting a light scattering state is one or more less than the total number of optical elements in one frame, various expressions and high brightness are maintained as described in Example 5 described later. Expression is possible.

Note that T ₁ and T ₂ in T ₁ / (T ₁ + T ₂ ) described above are the total time in which one of them is in a light scattering state in one frame when there are a plurality of optical elements. and T _1, any of which is the amount of time in the light transmission state and T _2. For example, in the case of FIG. 4, T ₁ and T ₂ shown in the figure correspond to this. In the case of FIG. 5, T ₁₁ + T ₂₁ corresponds to T ₁ , and T ₁₂ −T ₂₁ corresponds to T ₂ . As shown in FIG. 6, when the width of T ₁₁ is the same as the width of T ₂₁ , the width of T ₁₂ is the same as the width of T ₂₂ , and T ₂₁ is at the center of T ₁₂ , T ₁ and T ₂ have the lengths shown in the figure. In this case, the sum of T ₁₁ + T ₂₁ and T ₁₂ −T ₂₁ is the length of two periods.

  Here, the state of switching between the light scattering state and the light transmitting state will be described in more detail. In the optical element according to the present invention, when the driving voltage is changed, the light scattering state and the light transmission state are not switched in an instant, but the response speed of switching between the light scattering state and the light transmission state of the optical element. Usually, it exhibits a transitional state according to the above.

  For example, the switching between the light scattering state and the light transmission state of the optical element shown in FIG. 3 is as shown in FIGS. 7 and 8 if the transitional state between the rising edge and the falling edge is shown. Further, the switching between the light scattering state and the light transmission state of the optical element shown in FIG. 4 is as shown in FIG. The transitional state 7 indicated by hatching in FIGS. 7, 8, and 9 is greatly expanded in time from the other portions.

  In such a case, when the optical element finishes the transient state and becomes almost 100% light scattering state, it is projected from the image projector, and the light scattering state changes to a light transmitting state. Preferably, the projection from the image projector is stopped. This is because the light projected from the image projector is scattered by the optical element that scatters the light most. Although it may be projected at the timing as shown in FIG. 8, in the transient state, the ratio of the light directly projected to the observer increases, which is dazzling, so the timing of FIG. 7 is preferable. When there are two or more optical elements, the timing is as shown in FIG.

  In the case of the timings as shown in FIGS. 7 and 9, the above-mentioned transient state can be treated as if the optical element is in the light transmission state. In other words, a driving method is possible in which the fall time required for the transition state from the scattering of one optical element to the transparent state and the rise time required for the transition state of the next optical element from the transparency to the scattering overlap. is there. When the rise time and the fall time are substantially the same, the time can be used more effectively, and it becomes easy to obtain a bright display or an optical element with high transparency.

In this way, whether the transitional state is regarded as the light scattering state or the light transmission state can be determined according to the actual situation, but if it is desired to ensure a long time that can be handled as the light transmission state, the transient state Is preferably regarded as a light transmission state. T ₁ and T ₂ in the present invention can be applied to any of the above definitions.

  The display device according to the present invention repeats the driving timing for taking the light transmission state and the light scattering state as described above, so that the still image appears to float in the background or the image is It is possible to realize a state where there is a movement in the left, right, up, down, and diagonal directions, a state where a moving image appears to float in the scenery, and the like. It is also possible to realize a certain type of three-dimensional display, such as a multi-screen display or a switching display between the front and rear optical elements.

  In this case, it is often preferable to prevent the image projector and the shutter from being seen from the observer as the background because aesthetics are not hindered. This can be realized by projecting an image obliquely to the surface of the optical element or installing a blindfold.

  FIG. 10 shows a situation where a person is running on the optical device. By projecting image light including display elements onto a plurality of optical elements in order, display can be performed so as to move to the back side or the front side. In the present invention, in order to prevent the image projector from being seen by the observer, a blindfold plate is installed as necessary. The image projector and the shutter may be installed on the lower side or the upper side in relation to the position relative to the observer (FIG. 11), or may be installed on either the left or right side. When an image is projected in this way, a normal image will appear distorted. This can be suppressed by correcting the original image to be projected or using a correction lens. it can. Note that such consideration is not necessary when the image projector and the shutter may be visible to the observer. Although the case where the display element is a human is shown here, the display element may represent a living creature other than a human being, or may represent a thing other than a living creature.

  It is often preferable to make the periphery of the optical element transparent because the state in which the image appears to float in the air in the background is emphasized. In order to achieve this purpose, it is preferable to seal the periphery of the optical element with a transparent resin layer, and to make the frame transparent when there is a frame. In many cases, the peripheral part of the optical element is sufficient if the main part is transparent. For example, if the portion other than the connection portion with the external circuit is transparent, a state in which the image appears to float in the air in the background behind the scene is sufficiently emphasized.

  Any known sealing agent can be used as long as it is a highly transparent resin. If a highly transparent resin is used, the optical element becomes more transparent on the entire surface, and the state that the image appears to float in the air is emphasized. For example, when a glass substrate is used, a state in which a transparent glass floats in the air can be realized by using an epoxy resin or an acrylic resin having a refractive index close to that of glass. .

  Optical elements of any size can be used, including those with a diagonal length of as small as 10 cm or as large as 3 m, but generally speaking, they are larger than small. However, there are many cases where it is preferable to enjoy powerful images. Also, several optical elements can be connected to form a large optical element.

  In the case of joining, it is preferable that a liquid crystal layer is connected so that an image can be seen continuously as much as possible at the joining boundary. However, if the liquid crystal layers overlap at the joining boundary, the brightness of the image may appear different, which is not preferable.

  On the other hand, when creating a joining boundary part with a seal or frame part around the optical element, such a part cannot be switched between a light transmission state and a light scattering state. In this case, there is a problem that an image is not displayed on the part and the image is cut off.

  Therefore, it may be useful to make such a part transparent at all, and always to have a part or all of it in a light scattering state so as to always have a scattering property equivalent to that of an optical element. This is because an image can be displayed with few or no cuts even if there are cuts. In this case, even if the liquid crystal layers of all the optical elements are in the light transmissive state, this portion remains in the light scattering state, but there is not much discomfort.

  Although the above has mainly described the case where the time zones in which the liquid crystal layers of all the optical elements are in the light transmission state overlap, this condition is not an essential element depending on the aspect of the present invention. . If there are multiple optical elements and there are no overlapping time zones in which the liquid crystal layers of all the optical elements are in the light-transmitting state, the background and the image on the optical element can be viewed simultaneously. When the image on the optical element is viewed, the portion where the image is not projected on the optical element is milky white. However, it is still possible to give an impression that the image floats in the air as a whole, and some of the objects of the present invention can be achieved.

  For example, a display device including a plurality of optical elements that can repeatedly take a light transmission state and a light scattering state, and an image projector that projects an image onto the optical element, the optical elements being a liquid crystal and a mesogenic structure A liquid crystal layer in which the orientation pretilt angle of liquid crystal molecules is 60 degrees or more with respect to the substrate surface, and a pair of transparent substrates with electrodes sandwiching the liquid crystal layer. When a voltage is applied, the liquid crystal layer of the optical element takes a light scattering state, and when the voltage application between the transparent electrodes is stopped, the liquid crystal layer of the optical element takes a light transmissive state. The image is projected onto the optical element in the scattering state, and the observer can determine the repetition frequency of the frame consisting of the minimum unit of the combination of the light transmission state and the light scattering state on the optical element. Can be set within the range of not feel flicker display repeating frequency of image display device and the frame can be set to at least 30Hz is also an aspect of the present invention.

  Therefore, the aspects of the invention in which the liquid crystal layers of all the optical elements in the above description have a light transmission state overlap each other in the aspects of the invention in which the liquid crystal layers of all the optical elements have a light transmission state. Needless to say, there may be cases where there is no overlap.

  In the present invention, a projection image exhibiting a three-dimensional movement in the depth direction can be performed by combining projection images on a plurality of optical elements.

  The image display device according to the present invention is installed near the register of a convenience store, a head-up display for automobiles, a storefront production such as a show window, an information display installed near a reception in an office, factory, exhibition hall, etc. It can be used as an information display, a display device of an arcade game machine, etc., and a unique image can be enjoyed.

  In addition, the optical element according to the present invention uses a liquid crystal layer and a pair of transparent electrodes to provide a function capable of continuously displaying an image, such as time display, for example, It is also possible to provide the functions of other types of liquid crystal display devices such as reflective liquid crystal display devices. For example, it is possible to produce a display by creating a pattern electrode under the optical element and scattering a desired place.

  Since the optical element according to the present invention can be made transparent, it may be arranged on another display device. For example, in front of a vehicle-mounted instrument panel or in front of another meter. That is, an instrument, an information terminal, or a mirror can be placed behind the optical element.

  In addition to the method of using the electro-optic modulation layer as one functional layer, the optical element may be divided into electrodes or may have a plurality of arbitrary shapes. Moreover, you may laminate | stack the optical element of a some pattern shape.

  In addition, in the plurality of optical elements, by changing the optical elements to be scattered over time, a display similar to blinking can be performed, and the viewer can be alerted.

  In order to increase the impact resistance, it is desirable to fix the upper and lower substrates. For example, the upper and lower substrates can be fixed by using an adhesive spacer. It is preferable to select a highly transparent material for the adhesive spacer.

  It is also possible to fill all portions of the optical element that do not need to be displayed in a scattered manner with an adhesive resin. In addition, it is possible to adjust the scattering power by adjusting the area occupied by the adhesive spacer even in a place where scattering display is required. This is a very effective method especially when it is required that the background is visible to some extent.

  Examples of the present invention are shown below. In the examples, “parts” means parts by weight.

  An optical element having a schematic cross-sectional view shown in FIG. 1 was prepared as follows. First, 80 parts of nematic liquid crystal (AG-1016XX manufactured by Chisso Corporation) having a negative dielectric anisotropy, 20 parts of the curable compound represented by chemical formula (a), and 0.2 part of benzoin isopropyl ether are blended. Then, a mixed composition was prepared.

  Next, a pair of vertically aligned polyimide films (JALS-682-R3 manufactured by JSR Corporation) formed on the transparent electrode, having a length of 200 mm, a width of 200 mm, a thickness of 1.1 mm, and a refractive index of 1.54. This glass substrate was placed with the polyimide thin film facing each other, a small amount of resin beads with a diameter of 6 μm were placed in the gap, and an epoxy resin layer with a width of about 1 mm was provided on the four sides of the substrate by printing. The optical element periphery was sealed with a transparent resin layer.

Specifically, a part of the seal layer is left open, and after the seal layer is cured, the mixed composition is injected into the liquid crystal cell formed in this manner, and then a part of the seal layer is opened. It was sealed with an epoxy resin and cured to complete the seal layer 28 shown in FIG. Next, the curable compound was cured while the liquid crystal in which the curable compound was dissolved by the action of the polyimide film for vertical alignment was aligned in the direction perpendicular to the substrate surface to form a liquid crystal layer. Specifically, with the injected liquid crystal cell held at 40 ° C., about 2.5 mW / cm ² from the upper side and about 2.5 mW from the lower side by the Hg—Xe lamp having a dominant wavelength of about 365 nm. An optical element that was irradiated with UV light of / cm ² for 10 minutes and sealed with a transparent resin layer was obtained.

  FIG. 12 shows data of transmittance T with respect to drive voltage V (effective value) when evaluated with an optical system having an aperture angle of 5 °. The surface of the glass substrate is not subjected to anti-glare (AR) treatment. The transmittance when no voltage was applied was about 84%. The transmittance when a voltage of 40 V was applied was about 3%.

  As shown in FIG. 13, a transparent resin seal frame 29 may be provided at the periphery of the optical element to improve mechanical strength and prevent chemical alteration of the liquid crystal layer and the like. In this case, the optical element is double-sealed with a transparent resin layer. In this example, 20 optical elements 1 formed as described above were laminated with a transparent resin 17 made of silicone resin having a refractive index of 1.5 between them. The total thickness was about 20 cm. The arrangement configuration is shown in FIG. A signal (drive voltage) is given to each optical element 1 from the drive circuit 8 to control the optical state. When 20 optical elements 1 formed in this way are stacked and a transparent resin 17 of silicone resin is disposed between the optical elements, the outer surface of the optical element located on the foreground is placed outside the optical element located on the back side. The transmittance of light reaching the surface is about 30%. Note that the transmittance decreases when the number of stacked optical elements is increased.

  As the image projector 2, ELP-50 (Epson projector) was used. A mechanical rotary chopper was used as the shutter, and the rotation speed was 60 Hz and the opening time was about 50%.

  Switching of the transmitted light scattering state of the liquid crystal layer of the optical element 1 was also performed at 60 Hz and synchronized with the image projection at the timing shown in FIG.

  The driving for switching the liquid crystal layer of the optical element 1 between the light transmitting state and the light scattering state was performed by switching between a rectangular wave of 200 Hz and a voltage of 0V and 30V. The rise time was about 1.5 ms and the fall time was about 2 ms.

  For the observer 4, the optical element 10, the image projector 2, and the shutter 3 have the same arrangement as in FIG. 11. As a result, the observer 4 could see the image of the optical element and the scenery 5 behind the optical element simultaneously without flickering. In addition, since a light transmission state is completely achieved when no voltage is applied, there is a sense of openness when the image display device is not used, and a transparent image is floating in the space when the image display device is used. I was able to give an impression.

  Two optical elements prepared in the same manner as in Example 1 were used and arranged as shown in FIG. The distance between the optical element 1 and the optical element 1 ′ was about 50 mm so as to be almost parallel. The two optical elements were almost overlapped when viewed from the observer. Silicone resin was sandwiched between the two optical elements.

The same two image projectors as in Example 1 were used. A mechanical rotary chopper similar to that in Example 1 was used as the shutter, and the projection timing was adjusted so as to be as shown in FIG. T ₁₁ = 4 ms, T ₁₂ = 12 ms, T ₂₁ = 4 ms, T ₂₂ = 12 ms, T ₁ = 8 ms, and T ₂ = 8 ms were set.

  An image was displayed on the optical element 1 using the image projector 2, and a character image was displayed on the optical element 1 'using the image projector 2'. Two images were recognized at the same time without flickering, and the scenery behind the optical element could be seen without flickering, and a stereoscopic display with a sense of depth could be recognized.

  If this display device is used, a background such as Cinderella Castle (a trademark of Disney Enterprises, Inc.) is displayed on the optical element 1, and a dancing Mickey Mouse (registered trademark) is displayed on the optical element 1 'or displayed on the optical element 1. By moving the Mickey Mouse (registered trademark) back and forth, it is possible to realize a display with a sense of depth.

  In addition, when two image lights are displayed on the optical element 1 and the optical element 1 ′ so as to overlap each other, a sense of perspective can be obtained by making the luminance of the optical element 1 different from the luminance of the optical element 1 ′. It has been found that a stereoscopic image can be realized without the glasses generally required for stereoscopic display.

  When an image of Mickey Mouse (registered trademark), an image of Minnie Mouse (registered trademark), and an image of Cinderella Castle are displayed, for the image of Mickey Mouse (registered trademark), the luminance at the optical element 1 ′ is set to a relative value of 1, The luminance at the optical element 1 is set to a relative value of 0. For the Minnie Mouse (registered trademark) image, the luminance at the optical element 1 ′ is set to a relative value of 0.5, the brightness at the optical element 1 is set to a relative value of 0.5, As for the image of Cinderella Castle, if the luminance at the optical element 1 ′ is a relative value 0 and the luminance at the optical element 1 is a relative value 1, the image of the Mickey Mouse (registered trademark) is closest to the observer. A three-dimensional image that gives the impression that the image of the castle is the farthest and the image of Minnie Mouse (registered trademark) is in the middle is realized.

  If this is generalized, the brightness of the image projected on any two optical elements of two or more overlapping optical elements will be different from each other as in the case of Mickey Mouse (registered trademark) or Cinderella Castle. If they are different, a combination of images with different relative distances as described above can be realized. Note that in the above, any two do not mean only any two, there may be a plurality of such combinations, and any corresponding optical element belongs to a plurality of combinations. Also good.

  In this case, in the above example, the observer cannot see the image in a stereoscopic manner unless the display of the optical element 1 and the display of the optical element 1 ′ are combined. There is a case. In many cases, it is preferable to reduce the distance between the optical element 1 and the optical element 1 ′ in order to increase the range of angles that can be viewed stereoscopically. Generally speaking, the distance between the optical elements is preferably 0.4 to 200 mm, but the stereoscopic effect can be maintained between 0.4 and 50 mm, and the stereoscopic display can be viewed from almost any position. Is possible and more preferred. The distance between the optical elements is more preferably 2 mm ± 1 mm.

Incidentally, the front and back sides of both of the optical element was subjected to AR coating (low-reflective coating) process consisting of a dielectric multilayer film of SiO ₂ and TiO _2. As a result, an increase in contrast was realized due to a decrease in reflection of external light on the glass substrate surface. In addition, the display from the projection device was subjected to multiple reflections on the surface, and the problem of blurred images could be reduced.

  Since a plurality of optical elements are used, the surface of each optical element is preferably AR-coated. This is because low reflection can be realized.

  An optical element was produced in the same manner as in Example 1 except that the surface of the vertical alignment polyimide film was rubbed and the pretilt angle was set to 70 degrees.

  The rise time of the drive for switching the liquid crystal layer of the optical element between the light transmission state and the light scattering state was about 1.0 ms, and the fall time was about 1.5 ms.

  For the observer 4, the optical element 10, the image projector 2, and the shutter 3 have the same arrangement relationship as in FIG. As a result, as in Example 1, the observer 4 could see the image of the optical element and the scenery 5 behind the optical element simultaneously without flickering. Further, since no light is applied when no voltage is applied, as in the first embodiment, there is a feeling of openness when the image display device is not used, and when the image display device is used, the image is transparent in the space. I was able to give the impression that it was floating.

  When the image display device according to the first embodiment is used as a head-up display for automobiles, a traveling meter display for automobiles, a display for a show window, and an information display regarding a purchased item next to a register of a convenience store, the presence itself when not used. Is less obtrusive and does not give a feeling of pressure, has a feeling of openness, and can be used for a transparent display in which the background side of the optical element can be seen during use.

  When using it for a car, you can place the optical element on the top of the instrument panel as used in the head-up display of existing cars, or place it on the center console between the driver's seat and the passenger seat. Good. You can drive safely because you can see the situation in front of the vehicle while driving, and when there is no indication, it is transparent and there is no feeling of pressure.

  In this case, various displays such as information on the vehicle such as speed display and alarm display, navigation information, television display, video display, Internet display, ETC, and the like are possible.

  Even if the optical element size is about the same as the windshield size, there is no problem in operation. The image display device may be attached to the windshield or integrated. You may give the function of an optical element partially. An optical element may be placed between the front seat and the rear seat. Even in this case, there is an advantage that the person in the front seat and the person in the rear seat do not need to feel alienation.

  When used as a show window, an optical element can be placed in front of a product, and information that matches the image of the product can be flowed to attract the interest of passersby.

  When placed next to or above a register such as a convenience store, the conventional display body is not transparent, so the distance between the store clerk and the customer is generated and there is a feeling of alienation. However, when this display device is used, there is no sense of alienation. You may arrange at the reception desk in the same way. As the display at this time, it is possible to send a description of a product, information on a product for sale, a product for a limited time, a product for a limited amount, or a commercial message thereof.

  Five optical elements prepared in the same manner as in Example 1 were used, and the number of optical elements scattered within one frame was two. The optical element farthest from the observer is the optical element a, and the optical element b, the optical element c, the optical element d, and the optical element e are used as approaching the observer side. As an image, with the background such as Cinderella Castle displayed on the optical element a, the Mickey Mouse (registered trademark) is displayed on the optical element b in the first frame, and is displayed on the optical element c in the subsequent frame. The optical element d is displayed on the optical element d, and the optical element e is displayed on the subsequent frame.

  As a result, it was possible to give an impression that Mickey Mouse (registered trademark) was approaching the observer side. Conversely, by moving the Mickey Mouse (registered trademark) from the optical element e to the optical element d, the optical element c, the optical element b, and the optical element a, it was possible to give an impression of moving away from the observer. In addition, when 5 optical elements are always displayed in one frame, there is a defect that the entire display becomes dark. However, in this example, the same brightness can be realized with two optical elements.

  When the distance between the optical elements is small, the movement back and forth continuously feels. Although about 30 mm may be sufficient, 10 mm or less is good. In order to give a sense of distance, it is effective to increase the number of optical elements.

  In order to increase the size of the optical element, four optical elements prepared in Example 1 were bonded to form a large optical element. In the bonded portion, the glass width of the portion corresponding to the frame portion remaining outside the seal portion was set to 0.1 mm or less. In addition, among the portions inside the seal, a portion that does not have the function of transmission scattering for the purpose of insulation or the like is provided, but the width of the portion is 0.5 mm or less, and the portion that is not the display portion is as narrow as possible It comprised so that it might become. Thereby, the site | part which does not contribute to scattering by the joint of the optical element was made small as much as possible.

  As a result, although the image is cut, an image that is not unnatural as a whole can be displayed.

  In addition, a scattering resin in which beads having different refractive indexes are dispersed in a transparent epoxy resin is added to a portion that does not contribute to scattering, that is, a portion that cannot be switched between a light transmission state and a light scattering state, so that a light scattering state is always obtained. As a result, as a result of always having the same scattering property as that of the optical element, the image can be displayed without breaks, and a more natural image can be obtained.

  In order to increase the size of the optical element, a plastic substrate can be used instead of the glass substrate of Example 1. For example, a polycarbonate resin having a thickness of 0.2 mm is used for a plastic substrate, ITO is continuously formed on a roll-like polycarbonate having a width of 1 m, and a vertical alignment film is formed thereon. An optical element can be produced in substantially the same manner as in Example 1 except that two polycarbonates having a length of 2 m are used as substrates, and a liquid in which the material of the liquid crystal layer and the spacers are injected between the substrates. . As a result, it is possible to realize a large optical element having the same performance as that of the first embodiment.

  Instead of the resin beads for gap control of Example 1, an adhesive spacer capable of bonding the upper and lower substrates was used. Adhesive spacer liquid is applied to a substrate on which a polyimide film for vertical alignment (JALS-682-R3 manufactured by JSR) is formed on a transparent electrode, and patterned using a photolithographic method. Columnar spacers having a size of 6 μm were prepared. Thereafter, an optical element was produced by the same operation as in Example 1, but the upper and lower substrates were finally bonded by heat treatment. As a result, the phenomenon that the transparency when no voltage is applied due to impact or the like is greatly reduced.

  An optical device was formed by a method different from the above example (see FIG. 15). In the acrylic box prepared in advance, 20 optical elements 1 were sequentially arranged using a fixing member with a desired gap. The box size was 30 cm thick × panel size, and the arrangement pitch of the optical elements was about 9 mm. The panel size was 20 cm × 18 cm. Each optical element 1 includes two substrates, and each substrate has a thickness of 1.1 mm. Thereafter, a silicone resin in a solution state was poured into the box. In order to ensure the transparency of the display surface, the temperature and injection rate were controlled so as not to generate air bubbles. Thereafter, the silicone resin was cured to form the optical device 10 integrated as a whole. In the same manner as in Example 1, the optical element was driven and projected from the image projector, and a good display could be obtained. Moreover, a water tank may be used instead of a box, and each optical element 1 may be arrange | positioned in a water tank. And you may display the image which fish swims around.

1 is a schematic cross-sectional view of an optical element used in the present invention. The schematic diagram which shows an example of arrangement | positioning of the display apparatus which concerns on this invention. The schematic diagram which shows the drive timing which takes the light transmission state and light scattering state in the Example of FIG. The schematic diagram which shows the drive timing which takes the light transmission state and light scattering state in the example of FIG. The schematic diagram which shows the drive timing which takes the light transmission state and light scattering state in the example of FIG. The schematic diagram which shows the further drive timing which takes the light transmission state and light scattering state in the example of FIG. FIG. 4 is a waveform diagram showing a transient state of drive timing shown in FIG. 3. FIG. 4 is another waveform diagram showing a transient state of the drive timing shown in FIG. 3. FIG. 5 is a schematic diagram showing a transient state of drive timing shown in FIG. 4. The schematic diagram which shows an example of the use condition of the display apparatus of this invention. The schematic diagram which shows the other example of arrangement | positioning of the display apparatus concerning this invention. The graph which shows the VT characteristic of an optical element. The typical sectional view explaining the optical element in other examples of the present invention. The schematic diagram which shows the basic structural example of this invention. The schematic diagram which shows the other structural example of the optical element concerning this invention.

Explanation of symbols

1: Optical element 2: Image projector 3: Shutter 4: User 5: Background 6: Hidden plate 7: Transparent substance 10: Optical device

Claims (6)

An optical element in which an electro-optic modulation layer is sandwiched between a pair of substrates with electrodes and a drive circuit for driving the optical element are provided. The electro-optic modulation layer is configured to transmit light and scatter light according to a signal from the drive circuit. A display device capable of transferring two or more optical states including a state,
A plurality of optical elements are arranged, a transparent substance is provided between the outer surfaces of adjacent optical elements, and the optical state of each optical element is controlled by a drive circuit,
The transmittance of light from the outer surface of the optical element located at the foremost surface to the outer surface of the optical element located at the rearmost surface is 30% or more,
Furthermore, an image projector is provided, image light is projected from the image projector toward the outer surface of the optical element on the back surface, and the display is visually recognized from the outer surface side of the optical element on the front surface. .   The display device according to claim 1, wherein ten or more optical elements are arranged.   The display device according to claim 1, wherein the tensile modulus of the transparent material is 120 MPa or less.   The display device according to claim 1, wherein display is performed such that at least one display element constituting the display goes back and forth between the plurality of optical elements.   The display device according to claim 4, wherein display is performed such that the display element moves within the screen.   6. The display device according to claim 1, wherein a difference between a refractive index of the transparent substance and a refractive index of a material constituting the substrate is within 0.15.

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