JP4905251B2 - Display media - Google Patents

Description

  The present invention relates to a display medium.

  Cholesteric liquid crystal has a helical structure composed of rod-like molecules, and selectively reflects visible light near a specific wavelength when the helical pitch is in the optical wavelength order. This phenomenon is known as selective reflection of cholesteric liquid crystals. The reflectivity of the selective reflection can be changed by controlling the direction of the helical axis by electricity, magnetism, light, heat, stress, etc., or by destroying / generating the helical structure itself. In this way, the reflective liquid crystal display medium using cholesteric liquid crystal controls the on / off of the reflected light.

  Since the reflective liquid crystal display medium using cholesteric liquid crystal is a display element that performs display using external light as illumination, it does not require illumination power and has low power consumption. In addition, it has a memory property that can hold a display without a power source, and therefore, an expensive active matrix substrate such as a thin film transistor is not required for driving, a flexible substrate such as a resin substrate can be used, and a reflective plate is not used. It has features such as a high rate and vivid display.

  In this case, a multi-color reflective liquid crystal display medium can be obtained by stacking three cholesteric liquid crystal layers that selectively reflect the three primary colors of light, blue light, green light, and red light. Therefore, it is necessary to produce a light reflecting panel in which liquid crystals that reflect each color light are enclosed, and to stack three or more layers to form a display medium.

  On the other hand, in order to enclose liquid crystal between the substrates in each of the above-described light reflecting panels, it is necessary to provide a panel by bonding a pair of substrates so that ribs or the like can be provided between the substrates to maintain a certain distance. With regard to a method for manufacturing this display panel, a display medium that uses, for example, an ultraviolet curable PDLC (polymer dispersed liquid crystal) and does not have a clear rib between substrates is disclosed (for example, see Patent Document 1). ).

  In addition, the shape is copied using polydimethylsiloxane (PDMS) on the mold, and a liquid crystal mixed with a polymer precursor is sealed between substrates using the rib as a rib, and UV curing is performed using the polymer precursor. There is disclosed a method for manufacturing a panel in which phase separation is performed without enclosing a rib by irradiating ultraviolet rays through a photomask after sealing between substrates (see, for example, Patent Document 2).

Furthermore, before the substrates are stacked, a method is disclosed in which a resin structure and a spacer that are softened by heating are arranged on the substrates, and after sealing the liquid crystal, the resin structure is adhered to the substrate by heating (for example, (See Patent Document 3).
However, in any of the techniques, how to stack the manufactured panels has not been studied so far, except for sequentially aligning and stacking.
SID06 Digest p.1728 SID06 Digest p.1732 Japanese Patent No. 3777837

  An object of the present invention is to provide a display medium that can reduce image noise caused by ribs and electrode patterns in a display medium in which light control panels having ribs are laminated between substrates.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1 of the present invention has strip-shaped electrodes arranged in parallel through a gap of a certain width on the surface of each substrate, and the strip-shaped electrodes are opposed so as to be orthogonal to the x and y directions. A pair of substrates disposed;
Ribs arranged linearly in the x-direction and y-direction in the gap between the strip-shaped electrodes, separating the pair of substrates and forming a plurality of rectangular cells with a constant area between the substrates;
A plurality of dimming panels each having a dimming layer provided in the plurality of rectangular cells,
In one or more light control panels among the three or more layers of light control panels, at least one of the gaps and ribs of the electrodes is shifted in position in the z direction, which is the stacking direction, from the other light control panels. It is a display medium.

  According to a second aspect of the present invention, there is provided a light control panel in which at least one of the gaps and ribs of the electrodes is shifted in position in the z direction, which is the stacking direction, from the other light control panel. The display medium according to claim 1, wherein the display medium is stacked while being shifted in at least one direction.

  According to a third aspect of the present invention, there is provided a dimming panel in which at least one of the gaps and ribs of the electrodes is displaced in the z direction, which is the stacking direction, from the other dimming panel. 3. The display medium according to claim 2, wherein the display medium is laminated so as to be shifted in at least one direction of the x direction and the y direction by a gap width or a rib width from a position where gaps and ribs of the electrodes of the optical panel are aligned.

  In the invention according to claim 4, the second-layer light control panel directly above the lower-layer light control panel is shifted in the x direction, and the third-layer light control panel on the second-layer light control panel is further stacked. The display medium according to claim 2 or 3, wherein the light control panel is laminated so as to be shifted in the y direction with respect to the second light control panel immediately below.

  According to a fifth aspect of the present invention, there is further provided a fourth-layer light control panel on the third-layer light control panel in the x direction with respect to the third-layer light control panel immediately below. The display medium according to claim 4, wherein the light control panel is laminated in a direction opposite to the direction in which the light control panel is shifted.

According to the first aspect of the present invention, there is provided a display medium capable of reducing image noise caused by ribs or electrode patterns in a display medium in which a light control panel having ribs is laminated between substrates. be able to.
According to the second aspect of the present invention, it is possible to further prevent image moiré during display, and to minimize the shift width.
According to the invention of claim 3, it is possible to further prevent an increase in image shift.
According to the fourth aspect of the present invention, when three layers of light control panels are stacked, vertical and horizontal black and white lines that cause image noise in display can be efficiently eliminated.
According to the invention according to claim 5, when the four-layer light control panel is laminated, the vertical and horizontal black and white lines that cause image noise in the display are efficiently lost, and the display is excellent in the overall configuration balance. A medium can be obtained.

Hereinafter, the present invention will be described in detail.
The display medium of the present invention includes a pair of substrates having strip-shaped electrodes arranged in parallel through a gap of a certain width on the surface of each substrate, the strip-shaped electrodes being opposed to each other so as to be orthogonal to the x and y directions. And ribs arranged linearly in the x-direction and y-direction in the gaps between the strip-shaped electrodes, separating the pair of substrates and forming a plurality of rectangular cells with a constant area between the substrates, and the plurality of rectangles 3 or more layers of light control panels each having a light control layer provided in the cell, and in one or more light control panels of the three or more layers of light control panels, the gap between the electrodes and At least one of the ribs is characterized in that its position is shifted from another light control panel in the z direction which is the stacking direction.

  For example, in order to obtain a reflective liquid crystal display medium in which liquid crystal layers that selectively reflect blue light, green light, and red light are laminated, a light reflecting panel (light control panel) having a liquid crystal layer corresponding to each reflected light. ) And three or more of these layers must be laminated. The light reflecting panel in this case is manufactured by enclosing a liquid crystal layer between a pair of substrates facing each other via a rib.

In the above light reflecting panel, normally, strip-shaped electrodes having the same shape formed on each surface with a gap of a certain width are orthogonal to the x direction and the y direction for ease of manufacture, medium driving convenience, and the like. A plurality of rectangular cells arranged in a straight line in the x-direction and y-direction in a gap between the strip-like electrodes and spaced apart from each other, and having a certain area between the substrates. It is comprised from the rib to form and the liquid-crystal layer (light control layer) provided in the said some square cell.
Hereinafter, the present invention will be described with reference to a reflection type liquid crystal display medium as an example in comparison with a conventional configuration.

FIG. 2 is a schematic cross-sectional view of a conventional reflective liquid crystal display medium in which the light reflecting panels are stacked.
The liquid crystal display medium shown in FIG. 2 has a configuration in which a blue light reflecting panel 40, a yellow light reflecting panel 50, a green light reflecting panel 60, and a red light reflecting panel 70 are laminated in order from the top. A black light shielding layer 35 is formed on the back surface (lower side of the drawing) of the red light reflecting panel 70. In the figure, reference numerals 11 to 18 are transparent substrates, reference numerals 21 to 28 are electrodes, reference numerals 31 to 34 are liquid crystal layers, and reference numeral 36 is a rib.

  Here, the blue light, the green light, the yellow light, and the red light mean colored lights having peaks in wavelength ranges of 400 to 500 nm, 500 to 600 nm, 550 to 650 nm, and 600 to 700 nm, respectively. In the figure, reference numerals 11 to 18 are transparent substrates, reference numerals 21 to 28 are electrodes, reference numerals 31 to 34 are liquid crystal layers, and reference numeral 36 is a rib.

The blue light reflection panel 40 is formed by forming a liquid crystal layer 31 made of right-twisted cholesteric liquid crystal that selectively reflects blue light between two transparent substrates 11 and 12 on which orthogonal electrodes 21 and 22 are formed, respectively. The green light reflection panel 60 is formed by forming a liquid crystal layer 33 made of left-handed cholesteric liquid crystal that selectively reflects green light between two transparent substrates 15 and 16 on which electrodes 25 and 26 that are orthogonal to each other are formed. In the red light reflection panel 70, a liquid crystal layer 34 made of a left-handed cholesteric liquid crystal that selectively reflects red light is formed between two transparent substrates 17 and 18 each having a transparent electrode.
The yellow light reflecting panel 50 disposed between the blue light reflecting panel 40 and the green light reflecting panel 60 has yellow light between the two transparent substrates 13 and 14 on which the orthogonal electrodes 23 and 24 are formed. A liquid crystal layer 32 made of right-twisted cholesteric liquid crystal that selectively reflects is formed.

  In the reflection type liquid crystal display medium, only the liquid crystal layers 31, 33, or 34 that reflect blue light, green light, or red light are reflected when displaying blue, green, or red, and blue light and green are displayed when displaying cyan. The liquid crystal layers 31 and 33 that reflect light are set to a reflective state, and the liquid crystal layers 31 and 34 that reflect blue light and red light are set to a reflective state during magenta display. During yellow display, (1) only the liquid crystal layer 32 that reflects yellow light, or (2) the liquid crystal layers 33 and 34 that reflect green light and red light, or (3) yellow light, green light, and red light are displayed. The liquid crystal layers 32, 33 and 34 to be reflected are in a reflective state, and (3) is desirable for obtaining a high reflectance.

  Further, at the time of white display, all of the liquid crystal layers 31, 32, 33, and 34 that reflect blue light, yellow light, green light, and red light are brought into a reflection state. Further, if all of the liquid crystal layers are made colorless, a black display can be obtained by the light shielding layer 35.

  In each light reflecting panel, the configuration of the electrodes and the ribs is the same. For example, in the blue light reflecting panel 40, the surface of the substrate 11 and the substrate 12 is respectively in the x direction (for example, the horizontal direction in the figure) and the y direction. The strip-shaped electrodes 21 and 22 having a gap of a certain width are formed in parallel so as to be orthogonal to the (perpendicular to the paper surface in the drawing). In relation to the strip-shaped electrode 22 on the substrate 12, two strip electrodes 22 are formed. A rib 36 is provided for each electrode. In the configuration shown in FIG. 2, the arrangement configuration of these electrodes and ribs is the same in each light reflecting panel, and the positions of the electrodes and ribs in each panel are from top to bottom in the drawing (stacking direction ( in the z direction).

  When laminated in this way, at the positions of A1 to A3 on the observation side indicated by arrows, there are no ribs in the z direction and there are no electrodes (electrodes acting by applying a voltage, the same applies hereinafter), so that each panel is ideally positioned. If alignment is performed, the portion becomes white, and at positions B1 to B2, a transparent rib exists in the z direction and there is no electrode. Therefore, if alignment is ideally performed for each panel, the portion is black. It becomes.

FIGS. 3A and 3B are schematic enlarged views of the display medium in the display state as viewed from the observation side. FIG. 3A is a white display state (all liquid crystal layers are in a reflection state), and FIG. The liquid crystal layer is in a transparent state).
As described above, in the white display shown in FIG. 3A, the portion 103 where the electrode is present in the z direction and the portion 102 where the electrode is not present are white because the light is reflected by all the panels. Instead, the portion 101 where only the rib exists is a black line based on the light shielding layer 35. On the other hand, in the black display shown in FIG. 3B, both the portion 103 where the electrode exists in the z direction and the portion 101 where only the rib exists exist in black, but the portion 102 where the electrode does not exist in the z direction is white in the reflected state. It becomes the line of. In particular, when a regular pattern of white or black appears in a solid image displayed in a wide range as a photographic image, it is felt as noise of the image.

  As a result of investigations to avoid the above problems, the present inventors have found that the gaps and ribs of the electrodes in one or more of the three or more layers of light reflecting panels (light control panels) If at least one of the z-direction, which is the stacking direction, is misaligned with other light control panels, at least the color of the black line and the white line in the solid image is changed (the density is reduced or increased). It was found that image noise can be reduced.

Specifically, the above problem can be solved by shifting the position of at least one of the stacked color light reflecting panels in FIG.
That is, when white is displayed, black is displayed at the position B1 as described above. For example, if the yellow light reflecting panel 50 is laminated slightly shifted in the direction on the laminated surface, the ribs in the yellow light reflecting panel 50 are displayed. Shifts from the ribs in the other panels in the z direction, and is not transparent from the top to the bottom of the figure at the position B1. Therefore, at the time of white display, the position of B1 is not black, and the color of all or part of the black line as shown in FIG. 3A can be changed (black density is reduced).

  Further, regarding black display, the color is white at the position A1 in FIG. 2 as described above. For example, if the green light reflection panel 60 is laminated slightly shifted in a direction on the lamination surface, the green light reflection panel 60 is displayed. The portion without the electrode in FIG. 1 is shifted from the portion without the electrode in the other panel in the z direction, and at the position A1, it is not completely reflected from the top to the bottom of the figure. Therefore, the position of A1 is not completely white when white and black, and the color of all or part of the white line as shown in FIG. 3B can be changed (the density is increased).

  As described above, with respect to a liquid crystal display medium configured by stacking three or more layers of light reflecting panels, one or more panels are separated from other light reflecting panels in the z direction by at least one of electrode gaps and ribs. If lamination is performed so that the positions are shifted, for example, the image noise shown in FIG. 3 can be reduced.

  In the above description, the mode of shifting one or more of the laminated light reflecting panels without specifying the direction has been described. However, in this embodiment, the strip-shaped electrodes are orthogonal to the direction of shifting the light reflecting panel. It is desirable that the x direction and the y direction be the directions. By setting the shifting direction as the electrode or rib arrangement direction in this way, it is possible to prevent the occurrence of image moiré during display and to minimize the shift width for reducing image noise.

  That is, in the example of the display state shown in FIG. 3, for example, when the horizontal direction is the x direction in FIG. 3A, the vertical direction is the y direction. By shifting in at least one of the direction and the y direction, the black line 101 in FIG. 3A, the white line 102 in FIG. 3B, at least the entire vertical or horizontal line, or the entire line Even without this, it is possible to change the color (decrease or increase the density) with a uniform width along the line direction. Therefore, the image noise processing can be performed efficiently without unevenness.

FIG. 1 is a schematic cross-sectional view showing an example of the display medium of the present embodiment. Specifically, the second yellow light reflecting panel 50 from the top in the conventional reflective liquid crystal display medium shown in FIG. Is shifted by a distance P in the right direction in the drawing as indicated by a white arrow.
The configuration of the substrate, electrode, liquid crystal layer, and the like in the display medium shown in FIG. 1 is the same as that shown in FIG. 2 except that the yellow light reflecting panel 50 is misaligned with other panels.

In this display medium, the yellow light reflection panel 50 is shifted from the other light reflection panels by a distance P in the direction in which the strip-shaped electrodes 24 are arranged. If the arrangement direction of the electrodes 24 is the y direction, the yellow light reflection panel 50 is yellow. The light reflection panel 50 is displaced in the y direction. In this way, only by shifting the yellow light reflecting panel 50 from the other light reflecting panels, as is clear from the figure, for example, at the position of A1, all the panels are not portions without electrodes in the stacking direction (z direction). Further, at the position B1, all the panels in the stacking direction are not portions where only ribs exist.
In the display medium shown in FIG. 1, not only the yellow light reflecting panel 50 is displaced in the y direction, but also the green light reflecting panel 60 immediately below it may be displaced in the x direction (perpendicular to the paper surface). .

  Further, in the present embodiment, when the at least one light reflecting panel is shifted in the x direction and the y direction, as shown in FIG. 2, from the position where the gaps and ribs of the electrodes of each light reflecting panel are aligned in the z direction. It is desirable that the gaps or the rib widths are stacked while being shifted in at least one of the x and y directions. This is because when the light reflection panel is shifted beyond these widths, the image shift may increase.

That is, in the liquid crystal display medium shown in FIG. 2, when the gap width of the electrode is S and the width of the rib is T, for example, only the yellow light reflection panel 50 is a distance S in the right direction (for example, the x direction) in the drawing. By shifting only the portion corresponding to the yellow light reflecting panel 50 in the portion having no electrode in the z direction becomes a portion where the electrode exists just by the width, the vertical display in the black display shown in FIG. The entire white line 102 can be a line having a high density other than white.
In addition, the display medium laminated | stacked as mentioned above is corresponded when the distance P which shifts the yellow light reflection panel 50 in the display medium shown in FIG. 1 is made into the clearance gap width S of an electrode.

Similarly, for example, by shifting only the yellow light reflecting panel 50 in the right direction (for example, the x direction) in the drawing by the distance T, only the portion corresponding to the yellow light reflecting panel 50 in the portion where the rib in the z direction is present. Is a portion where there is no rib corresponding to the width, and therefore the entire vertical black line 101 in the white display shown in FIG. 3A can be a line having a low density other than black.
Specifically, this configuration corresponds to the case where the distance P for shifting the yellow light reflecting panel 50 in the display medium shown in FIG.

In this case, as is clear from FIGS. 3A and 3B, when the distance shifted in the x direction is the rib width T, for example, the density of the vertical black line 101 in FIG. At the same time, the vertical white line 102 in FIG. 3B can be made a line other than white by the rib width T. Therefore, when the light reflecting panel is shifted in accordance with the gap width S or the rib width T of the electrodes, the vertical black lines and white lines in FIGS. 3A and 3B are thereby lost (discolored) in full width. Is desirable.
For this purpose, it is desirable to adjust the distance shifted in the x direction to the larger one of the gap width S and the rib width T of the electrode. It is more desirable that both the black line and the white line disappear completely.

  Next, with respect to the display medium of the present embodiment in which the light control panels having three or more layers are stacked, a desirable aspect in the case where the light control panels having two or more layers are stacked while being shifted will be described. In the following description, the “light control panel” will be described. However, the configuration and arrangement of electrodes and ribs in this light control panel are the same as those described for the light reflection panel.

First, a case where up to the third layer is laminated will be described.
In this case, first, the second layer of the light control panel on the lowermost layer is shifted in the x direction and laminated, and then the third layer of the light control panel on the second layer is adjusted. It is desirable that the light panel is laminated with being shifted in the y direction with respect to the second light control panel immediately below.

  That is, in the display medium of the present embodiment, the strip-shaped electrodes are arranged to face each other so as to be orthogonal to the x direction and the y direction, and the ribs arranged in the gaps between these electrodes are similarly arranged in the x direction, y. It is arranged linearly in the direction. Therefore, when each dimming panel is ideally aligned and stacked, the portion where there is no electrode in the z direction and the portion where only the rib exists are formed linearly in the x and y directions. . Therefore, in order to eliminate both the vertical and horizontal white lines and black lines in FIG. 3 by the above-described laminating method, at least one layer of light control panel is one layer of light control panel in the x direction in three or more layers. Need to be stacked in the y direction.

For the above reasons, when stacking up to the third layer, it is desirable to stack the second layer and the third layer in different directions. In this case, of course, it is more desirable that the shifting distance is the gap width S or the rib width T of the electrodes.
In the above description, the “x direction” and “y direction” may be shifted to either the + side or the − side. Further, in the aspect shown in FIG. 1, the x direction and the y direction are not specified as the x direction or the y direction in the left-right direction or the direction perpendicular to the paper surface.

Further, a case where the fourth layer is laminated will be described.
In this case, the fourth-layer light control panel is shifted on the third-layer light control panel, and the second-layer light control panel is shifted in the x direction with respect to the third-layer light control panel immediately below. It is desirable to laminate in the direction opposite to the direction. That is, when the second layer of the light control panel is shifted to the x direction + side, when the fourth layer of the light control panel is stacked, the layers are shifted to the x direction-side and stacked.

This is because the second layer and the third layer are shifted in the x and y directions, so that both the portions having no electrodes and the portions having only ribs are shifted in the z direction. Therefore, it is preferable that the last fourth layer is aligned with the position of the lowermost layer (the position where normal alignment is performed) in terms of the overall configuration balance of the display medium.
In this case, of course, it is desirable that the distance to be shifted is the gap width S or the rib width T of the electrodes.

  With the laminated structure up to the fourth layer as described above, for example, the above-described reflective liquid crystal display medium using the light reflecting panel that reflects blue light, yellow light, green light, and red light can be handled. . Furthermore, even in the case where five or more layers of light control panels are stacked, if any of the panels includes at least the configuration described in the second and third layers, a display with a small amount of image noise is similarly achieved. A medium can be obtained.

Next, an actual method of laminating each light control panel will be described.
In the conventional laminated liquid crystal display medium or the like shown in FIG. 2, the display panels are aligned using the alignment marks provided outside the normal display area to perform lamination. The lamination method in the display medium of the present embodiment is not particularly limited. However, when the alignment mark is used, it is desirable to perform as follows.

Hereinafter, an example of stacking up to the third layer will be specifically described.
First, an alignment mark is formed on the substrate. This alignment mark can be formed on the substrate by vapor deposition or sputtering using a mask. At this time, it is desirable that the alignment mark is a cross mark or the like orthogonal to the same direction as the x direction and the y direction, and is composed of a pattern having the same width as the line width. Then, three light control panels from the lowest layer to the uppermost layer to be laminated using this substrate are manufactured. This will be described later.

Next, with respect to the alignment mark of the lowermost light control panel, the second light control panel immediately above is arranged so as to be shifted by the line width of the alignment mark regardless of the + side or the − side in the x direction. . Furthermore, on the second layer of the light control panel, the third layer of the light control panel is arranged so as to be shifted by the line width of the alignment mark regardless of the + side or the − side in the y direction with respect to the second layer directly below. Laminate. In addition, when performing lamination | stacking of four or more layers, it can carry out according to this.
According to such a laminating method, alignment marks can be formed on each substrate using the same mask, and the light control panel can be positioned simply and accurately simply by adjusting the position with the alignment marks. The display medium of the present embodiment can be obtained with almost the same man-hours as in the case of normal lamination.

Next, each member, material, etc. constituting the display medium of the present embodiment will be described.
As the substrate, a light-transmitting insulating material such as glass such as borosilicate glass or quartz glass, or a resin such as polyester, polycarbonate, or polyether sulfone can be used. The thickness of the substrate is preferably in the range of 50 to 500 μm.

For the electrode formed over the substrate, a light-transmitting conductive material such as indium tin oxide, tin oxide, or aluminum-added zinc oxide is used. These materials are formed into a thin film on a substrate by a sputtering method, a vapor deposition method, a sol-gel method, or the like, and processed into a strip shape by a photoetching method or the like to form an electrode. The electrodes are strip-shaped, and a plurality of the strip-shaped electrodes are formed in parallel at a constant width on one substrate. The width of the electrode is not particularly limited, but is preferably the same width for each strip, and it is also desirable that the substrates of one light reflecting panel have the same width (that is, the electrode pattern having the same shape).
In the present embodiment, the width of the strip-shaped electrode is desirably in the range of 80 to 600 μm, and the gap width between the electrodes is preferably in the range of 5 to 20 μm.

The substrate is provided with ribs for forming cells. The rib width is preferably adjusted in the range of 3 to 30 μm, more preferably in the range of 5 to 15 μm, and the height of the rib is preferably adjusted in the range of 2 to 20 μm. The rib is provided in a straight line in the gap between the strip-shaped electrodes. The gap between the electrodes is orthogonal due to the orthogonal arrangement of the electrodes, and the ribs provided in the gap are also orthogonal, resulting in the formation of square cells between the substrates. The square cell may be square or rectangular.
In the present embodiment, when the electrode resolution is as high as about 300 dpi, it is desirable to provide straight ribs every four strips of electrodes, and when the electrode resolution is as low as about 100 dpi, every other rib is provided. Is more preferred. Further, the ribs may not have the same spacing in the x direction and the y direction.
In addition, as a method of providing the ribs on the display medium, there are a both-rib method in which ribs are formed after forming the ribs on both opposing substrate surfaces, and a single-rib method in which ribs are formed only on one substrate.

  Examples of the method for forming ribs on the substrate surface include a screen printing method, a nanoimprinting method, a photolithography method, and an additive method. Among these methods, a photolithography method using a resist film is preferably used.

  As the light shielding layer 35 formed on the back side of the substrate 18 as shown in FIG. 1, a black color material that absorbs the entire visible wavelength range (400 to 700 nm), for example, a black pigment such as carbon black or aniline black, A paint containing a black dye or an inorganic material such as chromium oxide is used. For example, in the case of a reflective liquid crystal display medium that reflects four color lights shown in FIG. 1, the light shielding layer 35 may be provided below the liquid crystal layer 34 that reflects red light. It may also serve as an electrode or a substrate.

Further, when the layer structure as shown in FIG. 1 is adopted, a yellow or red filter can be provided between the panels as required.
These filters can be formed by a known method such as applying a colored paint containing a pigment or a dye on a substrate, or providing an acrylic resin or gelatin film on the substrate and dyeing with a dye.

As the light control layer, various materials such as a cholesteric liquid crystal, an electrochromic display element, a guest-host liquid crystal, and a configuration in which positively or negatively charged particles are arranged in a dispersion liquid can be used.
In particular, it is desirable to use chiral nematic liquid crystal (cholesteric liquid crystal) in a reflective liquid crystal display medium.

  In the case of the configuration shown in FIG. 1, the cholesteric liquid crystal used for the liquid crystal layers (light control layers) 31 to 34 includes, for example, liquid crystalline asymmetric carbon compounds such as cholesterol derivatives such as cholesteryl chloride and cholesteryl nonanoate. Benzylideneaniline, azobenzene, azoxybenzene, cyanobiphenyl, cyanoterphenyl, phenylcyclohexane, phenylbenzoate, cyclohexylcyclohexane, cyclohexylcarboxylic acid ester, phenylpyrimidine, phenyldioxane, cyclohexylcyclohexane ester, cyclohexylethane, cyclohexene, tolan, etc. An asymmetric carbon compound called a chiral agent such as 2-methyl-n-butylcyanobiphenyl is added to a known nematic liquid crystalline compound containing a chemical structure. The composition obtained by adding, can be used. These compounds may be low molecular compounds or high molecular compounds.

  In the present embodiment, it is desirable that the spiral twist directions of the liquid crystal layers 31 to 34 use opposite optical rotations for light of adjacent colors in the selective reflection wavelength range. That is, from the low wavelength side, the liquid crystal layer 31 that reflects blue light and the liquid crystal layer 33 that reflects green light, the liquid crystal layer 33 that reflects green light, the liquid crystal layer 32 that reflects yellow light, and the yellow light are reflected. It is desirable that the liquid crystal layer 32 and the liquid crystal layer 34 that reflects red light have opposite spiral twist directions.

  This is because the cholesteric liquid crystal has circular dichroism that reflects only the circularly polarized component in the same direction as the helical twist direction, and the theoretical maximum reflectance is only 50%, so the wavelength band where the reflection spectra overlap This is because, when the rotational directions of the circularly polarized light are different from each other, the reflectance is not affected by the reflective layer laminated thereon, as compared with the case where the rotational directions are the same.

  The liquid crystal layers 31 to 34 may contain components other than those described above. For example, the liquid crystal layers 31 to 34 may be formed by dispersing a polymer or an inorganic compound in a cholesteric liquid crystal in a gel, matrix, or fine particle form, or conversely in a polymer matrix. A so-called polymer having a functional group called mesogen that induces liquid crystallinity in the main chain or side chain of the polymer may be used, in which cholesteric liquid crystal is dispersed in the form of droplets or in the form of microcapsules. It may be a liquid crystal.

  In order to improve the display characteristics and display uniformity of the display medium, an alignment film may be provided at the interface between the electrode formed on each substrate surface and the liquid crystal layers 31, 32, 33, and 34. Good. As the alignment film, resins such as polyimide and polyvinyl alcohol, low molecular surface modifiers such as alkyl ammonium compounds and alkyl silane compounds, inorganic thin films such as SiO, and the like can be used. As the alignment film, a vertical alignment film is particularly preferable.

  It should be noted that members provided between adjacent liquid crystal layers such as a substrate, an electrode, and an alignment film need not disturb the polarization state. Therefore, it is desirable that these members have less light scattering.

First, an adhesive is applied to the end of one substrate on which an electrode is formed, and the other substrate on which an electrode is similarly formed is connected to the other panel via the ribs arranged as described above. Adhering at regular intervals so that both electrodes face each other. This is produced for each required color.
Next, in the case of a laminated structure like the display medium shown in FIG. 1, cholesteric liquid crystal capable of reflecting blue light, yellow light, green light, and red light is injected between a pair of substrates in each panel. Then, the substrate end portion is sealed, and the blue light reflection panel 40, the yellow light reflection panel 50, the green light reflection panel 60, and the red light reflection panel 70 are produced. The thickness of the liquid crystal layers 31, 32, 33, and 34 in each panel is set to a range of 2 to 20 μm.

In manufacturing the display medium of the present embodiment, it is desirable to provide an adhesive layer when the light control panels manufactured as described above are laminated.
For the adhesive layer, UV curable or thermosetting adhesives such as acrylic resin and epoxy resin, hot melt adhesives such as polyester and polyethylene-polyvinyl alcohol copolymer, adhesives such as polyvinyl acetate, etc. A known optical adhesive or pressure-sensitive adhesive can be used. However, the adhesive layer needs to have translucency. Note that the adhesive layer preferably has a refractive index close to that of the substrate material because it not only bonds the panels to each other but also reduces the surface reflection of the substrate and increases the contrast.

The layers for obtaining the reflective liquid crystal display medium as shown in FIG. 1 are laminated as follows, for example. First, a yellow filter is formed on the upper surface of the yellow light reflecting panel 50, a red filter is formed on the upper surface of the red light reflecting panel 70, and a light shielding layer 35 is formed on the lower surface. Finally, the blue light reflecting panel 40, the yellow light reflecting panel 50 formed with a yellow filter, the green light reflecting panel 60, and the red light reflecting panel 70 formed with the red filter and the light shielding layer 35 are respectively passed through an adhesive layer. Glue.
In FIG. 1, the yellow light reflecting panel 50 is the upper layer of the green light reflecting panel 60, but the green light reflecting panel 60 may be replaced with the upper layer of the yellow light reflecting panel 50.

  As described above, the display medium of the present invention has been described mainly by using the reflective liquid crystal display medium as an example. The example described above is a case where the cholesteric liquid crystal display medium is electrically driven and the display is rewritten. However, the display medium of the present invention is a liquid crystal display medium by external stimuli such as magnetism, light, heat, stress other than electricity. When the display is driven and the display is rewritten, the same can be applied and the same effect can be obtained. Further, the present invention can be applied not only to cholesteric liquid crystals but also to liquid crystals that absorb a specific wavelength.

It is a schematic cross section which shows an example of the display medium of this invention. It is a schematic cross section showing an example of a conventional reflective liquid crystal display medium. It is a typical enlarged view which shows an example of the display state in a reflection type liquid crystal display medium.

Explanation of symbols

11-18 Transparent substrate 21-28 Electrodes 31-34 Liquid crystal layer (light control layer)
35 Light-shielding layer 36 Rib 40 Blue light reflection panel (light control panel)
50 Yellow light reflection panel (light control panel)
60 Green light reflection panel (light control panel)
70 Red light reflection panel (light control panel)
101 A portion where there is no electrode in the laminating direction and there is only a rib 102 A portion where no electrode exists in the laminating direction 103 A portion where an electrode exists in the laminating direction

Claims (5)

A pair of substrates having strip-shaped electrodes arranged in parallel on the surface of each substrate through a gap of a certain width, the strip-shaped electrodes being opposed to each other so as to be orthogonal to the x direction and the y direction;
Ribs arranged linearly in the x-direction and y-direction in the gap between the strip-shaped electrodes, separating the pair of substrates and forming a plurality of rectangular cells with a constant area between the substrates;
A plurality of dimming panels each having a dimming layer provided in the plurality of rectangular cells,
In one or more light control panels among the three or more layers of light control panels, at least one of the gaps and ribs of the electrodes is shifted in position in the z direction, which is the stacking direction, from the other light control panels. A display medium characterized by that.   A dimming panel in which at least one of the gaps and ribs of the electrodes is shifted in position from the other dimming panel in the z direction, which is the stacking direction, is stacked while being shifted in at least one direction of the x direction and the y direction. The display medium according to claim 1, wherein the display medium is provided.   A dimming panel in which at least one of the gaps and ribs of the electrodes is shifted in position with respect to another dimming panel in the z direction which is the stacking direction, the gaps and ribs of the electrodes of each dimming panel in the z direction 3. The display medium according to claim 2, wherein the display medium is stacked so as to be shifted in at least one of the x direction and the y direction by a gap width or a rib width from a position where the two are aligned.   The second light control panel directly above the lowermost light control panel is shifted in the x direction and laminated, and the third light control panel on the second light control panel is placed on the bottom 2 light control panel. The display medium according to claim 2, wherein the display medium is laminated while being shifted in the y direction with respect to the light control panel of the layer.   Further, on the third-layer light control panel, the fourth-layer light control panel is shifted in the x direction with respect to the third-layer light control panel immediately below, and the second-layer light control panel is shifted. The display medium according to claim 4, wherein the layers are stacked in opposite directions.

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