JP6004127B1 - Dimming cell - Google Patents

Abstract

A dimming cell capable of reducing the influence of interference of diffracted light by a plurality of spacers and providing observation light with excellent visibility. A light control cell is disposed between a pair of polarizing plates (a first polarizing plate and a second polarizing plate) and a pair of polarizing plates (a first polarizing plate and a second polarizing plate). A pair of electrodes (first transparent electrode 25 and second transparent electrode 26) and a pair of alignment films (first alignment film 27) disposed between the pair of electrodes (first transparent electrode 25 and second transparent electrode 26). And a second alignment film 28). A plurality of spacers 30 are provided that support at least one of the pair of alignment films and two-dimensionally contact with at least one of the pair of alignment films. At least a part of the plurality of spacers 30 is not constant in distance to the other spacers 30 that are closest to each other. A liquid crystal layer 29 is disposed between the plurality of spacers 30 between the pair of alignment films. [Selection] Figure 2

Description

  The present invention relates to a light control cell that performs light control by controlling the alignment of liquid crystal.

  For example, an electronic blind or the like in which a light control cell (light control material) is installed in a window or a door and the transmission of external light is controlled by the light control cell is known. As such a light control cell, for example, a liquid crystal can be preferably used.

  The light control cell using liquid crystal is, for example, a liquid crystal cell formed by sandwiching a liquid crystal layer between a pair of transparent film materials and a pair of alignment films forming a transparent electrode, and this liquid crystal cell is formed by a linear polarizing plate for taking out linearly polarized light. It is produced by sandwiching. When dimming using a dimming cell that uses liquid crystal, the light transmission is controlled by controlling the electric field applied to the liquid crystal layer to change the orientation of the liquid crystal molecules contained in the liquid crystal layer. For example, the blocking and transmission of extraneous light can be switched, or the amount of transmitted light can be changed continuously.

  For example, Patent Document 1 discloses a liquid crystal panel that is provided in a window, door, or the like of a house and can control a transparent state and an opaque state. According to this liquid crystal panel, a plurality of divided liquid crystal panels are arranged side by side, and each divided liquid crystal panel can be individually controlled to a transparent state and an opaque state.

  Moreover, patent document 2 discloses the light control glass window which can adjust light transmittance with a various pattern according to the change of a sunlight condition. According to this light control glass window, the light transmittance can be adjusted by changing the voltage acting on the liquid crystal sealed between the two transparent glass plates to change the optical characteristics of the liquid crystal.

JP 03-47392 A Japanese Patent Laid-Open No. 08-184273

  In a light control cell having a liquid crystal cell, a spacer is provided between a pair of transparent film materials (alignment films) constituting the liquid crystal cell, and the liquid crystal layer may be held at a desired thickness by the spacer. In this case, for example, an alignment layer can be prepared by preparing a spacer and then forming a thin film such as polyimide and performing a rubbing process on the thin film, and the alignment layer can regulate the alignment of the liquid crystal material.

  Such a spacer can be formed by various methods. For example, a large number of regularly arranged spacers can be formed with high accuracy at a time based on a photolithography technique. In order to easily and accurately form a large number of spacers, it is common to arrange all the spacers regularly and adjust the distance between the spacers to be constant.

However, as a result of diligent research, the present inventors have found that the regularity of spacer arrangement is high and the distance between the spacers is constant. It was found that point light sources can be recognized as blurred light.
In other words, when the spacers are regularly arranged, interference of diffracted light by the spacers occurs periodically, and the diffracted lights are periodically strengthened, so that the point light source appears larger than the original size, and the dimming cell The visibility of the observation light that has passed through is deteriorated.

  Therefore, in a dimming cell provided with a large number of spacers, it is desired to propose a new method for reducing the influence of interference of diffracted light by the spacers and providing observation light with excellent visibility. However, in the prior art documents (for example, the above-described Patent Documents 1 and 2), no proposals effective for satisfying such a demand are made.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a light control cell capable of reducing the influence of interference of diffracted light by a plurality of spacers and providing observation light having excellent visibility. And

  One embodiment of the present invention is a pair of polarizing plates, a pair of film substrates disposed between a pair of polarizing plates, a pair of electrodes disposed between a pair of polarizing plates, and a pair of electrodes. A pair of alignment films, a plurality of spacers supporting at least one of the pair of alignment films and in two-dimensional contact with at least one of the pair of alignment films, and a plurality of spacers between the pair of alignment films And a liquid crystal layer disposed therebetween, and at least a part of the plurality of spacers relates to a light control cell in which a distance to another spacer having the closest distance is not constant.

  According to this aspect, since the distance between spacers is not constant, the influence of interference of diffracted light by a plurality of spacers can be reduced, and observation light with excellent visibility can be provided.

  Each of the plurality of spacers may have a flat first bottom portion that contacts one of the pair of alignment films, and a second bottom portion that faces the first bottom portion.

  According to this aspect, the alignment film can be accurately supported by each spacer. Note that the plurality of spacers of this aspect can be suitably formed based on, for example, photolithography technology.

  The plurality of spacers may be made of a photocurable resin.

  According to this aspect, each spacer can be easily formed using the photocuring performance of the photocurable resin. Note that the plurality of spacers of this aspect can be suitably formed based on, for example, photolithography technology.

  The plurality of spacers may be configured by repeatedly arranging unit patterns composed of three or more spacers arranged in a predetermined relative positional relationship.

  According to this aspect, the plurality of spacers can be easily formed while reducing the influence of diffracted light interference caused by the plurality of spacers.

  Each of the plurality of spacers may have a tapered shape that tapers from one of the pair of alignment films toward the other.

  According to this aspect, the alignment film can be accurately supported by each spacer.

  The taper angle of each of the plurality of spacers may be in the range of 75 ° to 85 °.

  According to this aspect, an appropriate alignment regulating force can be imparted to the liquid crystal layer by the alignment film while accurately supporting the alignment film by each spacer.

  At least one of the pair of polarizing plates may be entirely or partially curved.

  According to this aspect, the light control cell can be applied to the curved structure.

  Each of the plurality of spacers includes a core portion and a covering portion that covers at least a part of the core portion, and penetrates one of the pair of alignment films and the liquid crystal layer, and the other of the pair of alignment films. A first support surface that is in two-dimensional contact with the first support surface, and a second support surface that is in two-dimensional contact with one of the pair of electrodes. At least a part of the support surface may be formed by the core portion.

  According to this aspect, each spacer can be formed with high accuracy based on so-called photolithography technology.

  According to the present invention, since the distance between the spacers is not constant, there is no periodicity in the interference between the diffracted lights by each spacer. Therefore, the influence of interference of diffracted light by a plurality of spacers is reduced, and observation light with excellent visibility can be provided.

FIG. 1 is a conceptual diagram illustrating an example of a light control system. FIG. 2 is a diagram illustrating an example of a cross section of the light control cell. FIG. 3 is a diagram for explaining the taper angle of each spacer. FIG. 4 is a diagram for explaining the influence of interference of diffracted light when the spacers are regularly arranged. FIG. 5 is a diagram for explaining the influence of interference of diffracted light when the spacers are irregularly (randomly) arranged. FIG. 6 is a plan view showing the concept of an arrangement example (modification) of spacers. 7 shows enlarged cross-sectional shapes of the liquid crystal layer and the spacer, (a) shows a spherical spacer, and (b) shows a columnar (conical truncated cone) spacer shown in FIG. FIG. 8 is a diagram illustrating another example of a cross section of the light control cell. FIG. 9 is a diagram for explaining an example of a mask pattern determination method.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for convenience of illustration and understanding, the scale and size ratio of each element are exaggerated and changed from the actual scale and size ratio. Further, in this specification, the terms “plate”, “sheet” and “film” are not distinguished from each other only based on the difference in designation. For example, the term “plate” is a concept including a member that can be called a sheet or a film. In addition, the terms used in this specification, the geometric conditions, and the terms that specify the degree thereof (for example, terms such as “parallel”, “orthogonal” and “same”, length and angle values, etc.) are strictly Without being bound by any meaning, it is interpreted as meaning a range where substantially equivalent and similar functions can be expected.

  FIG. 1 is a conceptual diagram illustrating an example of a light control system 5.

  The light control cell 10 of this example has a layer made of a liquid crystal material containing liquid crystal molecules as will be described later, and can switch between blocking and transmitting light and changing light transmittance (transmittance). . The application object of the light control cell 10 is not specifically limited, Typically, the light control cell 10 is applicable with respect to a window, a door, etc. In particular, a columnar spacer described later is excellent in position fixing performance, and the position is not easily changed by an external force such as vibration. Therefore, the dimming cell 10 having a columnar spacer, which will be described later, can be suitably used even in an environment where an external force such as vibration is applied, and can be applied to, for example, a window (for example, a skylight) installed in a house. .

  The dimming cell 10 is connected to a dimming controller 12, and a sensor device 14 and a user operation unit 16 are connected to the dimming controller 12. The dimming controller 12 can control the dimming state of the dimming cell 10, switch light blocking and transmission by the dimming cell 10, and change the light transmittance in the dimming cell 10. Specifically, the dimming controller 12 adjusts the electric field applied to the liquid crystal layer of the dimming cell 10 to change the orientation of the liquid crystal molecules in the liquid crystal layer, thereby blocking and transmitting light by the dimming cell 10. It can be switched and the light transmission can be changed.

The dimming controller 12 can adjust the electric field applied to the liquid crystal layer based on an arbitrary method.
For example, the dimming controller 12 adjusts the electric field applied to the liquid crystal layer according to the measurement result of the sensor device 14 or an instruction (command) input by the user via the user operation unit 16, and the light from the dimming cell 10. It is possible to switch between blocking and transmitting light and changing the light transmittance. Therefore, the dimming controller 12 may automatically adjust the electric field applied to the liquid crystal layer according to the measurement result of the sensor device 14 or manually according to a user instruction via the user operation unit 16. You may adjust. Note that the measurement target by the sensor device 14 is not particularly limited, and for example, the brightness of the usage environment may be measured. In this case, light blocking and transmission switching or light transmittance change by the dimming cell 10 is used. This is done according to the brightness of the environment. In addition, both the sensor device 14 and the user operation unit 16 are not necessarily connected to the dimming controller 12, and only one of the sensor device 14 and the user operation unit 16 may be connected. .

  FIG. 2 is a diagram illustrating an example of a cross section of the light control cell 10.

  The light control cell 10 of this example includes a pair of polarizing plates (first polarizing plate 21 and second polarizing plate 22) and a pair of transparent electrodes (first transparent electrode 25 and second polarizing plate) disposed between the pair of polarizing plates. A transparent electrode 26) and a pair of alignment films (a first alignment film 27 and a second alignment film 28) disposed between the pair of transparent electrodes. In this example, a pair of films is disposed between the pair of polarizing plates (first polarizing plate 21 and second polarizing plate 22) and outside the pair of transparent electrodes (first transparent electrode 25 and second transparent electrode 26). A base material (the 1st film base material 23 and the 2nd film base material 24) is arrange | positioned. That is, a pair of transparent electrodes (first transparent electrode 25 and second transparent electrode 26) are disposed between a pair of film base materials (first film base material 23 and second film base material 24), and a pair of polarizing plates ( The 1st polarizing plate 21 and the 2nd polarizing plate 22) are arrange | positioned on the outer side of a pair of film base material (the 1st film base material 23 and the 2nd film base material 24).

  Further, in this example, at least one of the pair of alignment films (first alignment film 27 in this example) is supported, and at least one of the pair of alignment films (first alignment film 27 in this example) is two-dimensional. A plurality of columnar spacers 30 that are in contact with each other, that is, in surface contact, are provided. A liquid crystal layer 29 is filled between a plurality of spacers 30 between the pair of alignment films (the first alignment film 27 and the second alignment film 28).

  The plurality of spacers 30 extend at least between “the boundary surface Sb2 between the first alignment film 27 and the liquid crystal layer 29” and “the boundary surface Sb1 between the second alignment film 28 and the liquid crystal layer 29”. It only has to exist. Therefore, for example, a plurality of spacers 30 may be disposed only between the first alignment film 27 and the second alignment film 28. 2, the second alignment from the second transparent electrode 26 (in the example illustrated in FIG. 2, “the boundary surface Sb <b> 3 between the second transparent electrode 26 and the second alignment film 28”). A plurality of spacers may be provided so as to penetrate the film 28 and the liquid crystal member 29 and come into contact with the first alignment film 27. Note that the present invention can be similarly applied to the case where the spacer 30 is provided only between the first alignment film 27 and the second alignment film 28 or the case where the spacer indicated by reference numeral 30a in FIG. 2 is provided.

  The first polarizing plate 21 and the second polarizing plate 22 each have a unique polarization axis and absorption axis, and allow only light polarized in a specific direction to pass therethrough. For example, when light traveling in the direction from the second polarizing plate 22 toward the first polarizing plate 21 (see the arrow “L” in FIG. 2) enters the dimming cell 10, the second polarizing plate 22 out of the light. Only light polarized in the same direction as the polarization axis passes through the second polarizing plate 22 and enters the second film base 24, and also travels from the first film base 23 toward the first polarizing plate 21. Among them, only light polarized in the same direction as the polarization axis of the first polarizing plate 21 passes through the first polarizing plate 21 and travels outward. The arrangement form of the first polarizing plate 21 and the second polarizing plate 22 is not particularly limited, and the arrangement form of the first polarizing plate 21 and the second polarizing plate 22 is related to the alignment state of the liquid crystal molecules contained in the liquid crystal layer 29. It is determined. Typically, a state called “cross Nicol” in which the first polarizing plate 21 and the second polarizing plate 22 are arranged so that the polarization axes are orthogonal to each other, or the first polarizing plate so that the polarization axes are parallel to each other. There is a state called “parallel Nicol” in which 21 and the second polarizing plate 22 are arranged.

  For example, when it is desired to improve the rigidity of the light control cell 10, the first film base material 23 and the second film base material 24 are configured by a transparent member having excellent rigidity. In addition, by using the first film base material 23 and the second film base material 24 that are rich in flexibility, it is difficult to use a glass base material, “bonding the light control cell 10 to a curved surface” Becomes easier.

  The first transparent electrode 25 and the second transparent electrode 26 apply a desired electric field to the liquid crystal layer 29 when a voltage is applied by the dimming controller 12 (see FIG. 1). The members constituting the first transparent electrode 25 and the second transparent electrode 26 and the arrangement form of the first transparent electrode 25 and the second transparent electrode 26 are not particularly limited. For example, the 1st transparent electrode 25 and the 2nd transparent electrode 26 can be comprised with members excellent in visible light transmittance | permeability and electroconductivity, such as indium tin oxide (ITO: Indium Tin Oxide).

  The first alignment film 27 and the second alignment film 28 are members for aligning the liquid crystal molecule group included in the liquid crystal layer 29 in a desired direction. The alignment method of the liquid crystal layer 29 by the first alignment film 27 and the second alignment film 28 is not particularly limited, but in this example, a TN (Twisted Nematic) type liquid crystal whose molecular arrangement (molecular alignment) is twisted by 90 degrees is used. The method for imparting the alignment function of the first alignment film 27 and the second alignment film 28 is not particularly limited. For example, the alignment directions of the first alignment film 27 and the second alignment film 28 are changed by rubbing using a member such as nylon. The alignment directions of the first alignment film 27 and the second alignment film 28 may be specified by irradiation with linearly polarized ultraviolet rays.

  Each of the plurality of spacers 30 is in surface contact with at least one of the pair of alignment films (first alignment film 27 in this example), and from one of the pair of alignment films (second alignment film 28 in this example). The other has a tapered shape that tapers toward the first alignment film 27 in this example. In this example, each of the plurality of spacers 30 includes a flat first bottom 31 that contacts one of the pair of alignment films (in this example, the first alignment film 27), and a second bottom that faces the first bottom 31. 32. In FIG. 2, for the sake of convenience, each spacer 30 portion on the boundary surface Sb1 between the second alignment film 28 and the liquid crystal layer 29 is shown as a second bottom portion 32. When the spacer 30 extends from the boundary surface Sb3 between the second alignment film 28 and the second transparent electrode 26, each spacer 30 on the boundary surface Sb3 between the second alignment film 28 and the second transparent electrode 26 is displayed. May be regarded as the second bottom portion 32.

  The spacer 30 shown in FIG. 2 has a truncated cone shape in which the diameter linearly changes according to the distance from the second alignment film 28 and the side surface angle is substantially constant, but is not limited thereto. The diameter of the spacer 30 may change nonlinearly according to the distance from the second alignment film 28, for example, the diameter may change exponentially with respect to the distance from the second alignment film 28, The diameter may change in proportion to the square root of the distance from the bi-alignment film 28. In the example shown in FIG. 2, the spacer 30 has a tapered shape (forward tapered shape) that tapers from the second alignment film 28 toward the first alignment film 27, but from the first alignment film 27 to the second alignment film 28. The taper shape (reverse taper shape) which tapers toward may be sufficient.

  From the viewpoint of realizing the desired alignment of the liquid crystal layer 29 while ensuring the function as a spacer, the taper angle θ of each of the plurality of spacers 30 is preferably in the range of 75 ° to 85 °.

  FIG. 3 is a diagram for explaining the taper angle θ of each spacer 30. Here, the taper angle θ of each spacer 30 is between the both end portions of each spacer 30 (in FIG. 3, the uppermost position (first bottom portion 31) in each spacer 30) with respect to the stacking direction in the cross section of each spacer 30. The side portion Lp of each spacer 30 at a position spaced from the lowermost position of each spacer 30 by one third (1/3) of the distance of the lowest position (to the second bottom portion 32). The tangent line Lt is expressed by an angle formed with a line H extending in the horizontal direction perpendicular to the stacking direction. That is, of the side surfaces of each spacer 30, the tangent line Lt of the portion Lp separated from the second bottom 32 by a distance corresponding to one third of the total length of each spacer 30 in the stacking direction, and the line H extending in the horizontal direction The taper angle θ of each spacer 30 is represented by the angle formed between them.

  In the present embodiment, at least some of the plurality of spacers 30 are not constant in distance to the other spacers 30 that are closest to each other. That is, in the example shown in FIG. 2, “the distance (distance) D1 between the central spacer 30 and the left spacer 30” and “the distance D2 between the central spacer 30 and the right spacer 30” are “D1. ≠ D2 ”is satisfied.

  The distance between the spacers 30 indicating “the distance to the other spacer 30 with the closest distance” is typically represented by the shortest distance between the spacers 30. For example, in the case of the forward tapered spacer 30 shown in FIG. 2 (that is, the size of the first bottom 31 <the size of the second bottom 32), the “distance between the spacers 30” is represented by the distance between the second bottoms 32. On the other hand, in the case of the inversely tapered spacer 30 (that is, the size of the first bottom 31> the size of the second bottom 32), the “distance between the spacers 30” is represented by the distance between the first bottoms 31.

  FIG. 4 is a diagram for explaining the influence of interference of diffracted light when the spacers 30 are regularly arranged. FIG. 4 shows a case in which a plurality of spacers 30 are two-dimensionally arranged with respect to two directions of the light traveling direction L and the direction orthogonal to the traveling direction L, but are orthogonal to the light traveling direction L. In the case where the spacer 30 is arranged one-dimensionally in the direction in which the same occurs, the same effect is brought about.

  As shown in FIG. 4, when the spacers 30 are regularly arranged and the distance between adjacent spacers 30 (particularly the distance in the direction orthogonal to the light traveling direction L) is constant, interference of diffracted light occurs periodically, The visible light area is enlarged. Therefore, assuming the light from the point light source, if the distance between the adjacent spacers 30 is constant, the diffracted lights intensify with each other at a constant period. It looks very blurred.

  FIG. 5 is a diagram for explaining the influence of interference of diffracted light when the spacers 30 are irregularly (randomly) arranged. Note that FIG. 5 shows a case where a plurality of spacers 30 are two-dimensionally arranged with respect to two directions, ie, the light traveling direction L and the direction orthogonal to the traveling direction L, but are orthogonal to the light traveling direction L. In the case where the spacer 30 is arranged one-dimensionally in the direction in which the same occurs, the same effect is brought about.

  As shown in FIG. 5, when the spacers 30 are irregularly arranged and the distance between the adjacent spacers 30 (particularly the distance in the direction perpendicular to the light traveling direction L) is not constant, the interference of the diffracted light is periodically generated. Does not occur, and the visible light region does not change. Therefore, assuming light from a point light source, if the distance between adjacent spacers 30 is not uniform, the interference zone of the diffracted light becomes random, and the light intensity is such that the influence of the interference of the diffracted light cannot be visually recognized. Since it is embodied, the light from the point light source can be seen in its original size.

  Therefore, by using the dimming cell 10 according to the present embodiment, “at least some of the plurality of spacers 30 are not constant in distance to the other spacers 30 that are closest to each other”. It is possible to reduce the influence of interference of diffracted light and to provide observation light with excellent visibility.

The method of determining the specific position of “the plurality of spacers 30 whose distances to the closest spacers 30 are not constant” is not particularly limited, and can be appropriately determined based on an arbitrary method.
For example, the specific positions of the plurality of spacers 30 may be determined in accordance with a method for determining the generating point of the Voronoi diagram. Further, for example, the specific positions of the plurality of spacers 30 may be determined by determining the maximum value and the minimum value of the distance between two adjacent spacers 30 and using them as constraint conditions.

  In addition, it is not necessary for all the spacers 30 provided in the light control cell 10 to satisfy the condition that “the distance to the other spacer 30 with the shortest distance is not constant”. Even when the condition that the distance to the other nearby spacer 30 is not constant is satisfied, it is possible to reduce the influence of interference of diffracted light and to provide observation light with excellent visibility.

  In addition, all the spacers 30 provided in the dimming cell 10 may be randomly arranged without mutual relation, but a plurality of spacers 30 (three or more spacers 30) arranged in a predetermined relative positional relationship. A plurality of spacers 30 provided in the dimming cell 10 may be configured by repeatedly arranging the unit pattern configured by.

  FIG. 6 is a plan view showing a concept of an arrangement example (modification example) of the spacer 30. In the example shown in FIG. 6, for the plurality of spacers 30 (unit pattern 34) included in the predetermined unit pattern area 40, the condition “the distance to the other spacer 30 with the closest distance is not constant” is satisfied. A plurality of spacers 30 (unit patterns 34) included in the unit pattern area 40 are repeatedly arranged, whereby a plurality of spacers 30 provided in the light control cell 10 are configured. The shape and size of the unit pattern area 40 are not particularly limited, but a rectangular area determined according to the entire area where the spacer 30 is provided is preferably determined as the unit pattern area 40. For example, a square area of 10 mm square is defined. It can also be determined as a unit pattern area 40. Further, the specific number and arrangement of the spacers 30 included in the unit pattern area 40 are not particularly limited.

  By repeatedly arranging the plurality of spacers 30 (unit patterns 34) included in the unit pattern area 40 in this way, the influence of the interference of diffracted light by each spacer 30 is effectively reduced, and a large number of spacers 30 can be simplified. Can be provided. Therefore, this modification is suitable when the area where the spacer 30 is provided is wide, for example.

  The spacer 30 according to the present embodiment has a columnar shape as described above, and is excellent not only in position fixability but also in light alignment.

  7 shows an enlarged cross-sectional shape of the liquid crystal layer 29 and the spacer 30, (a) shows a spherical spacer 30, and (b) shows a columnar (conical truncated cone) spacer 30 shown in FIG. 2. In general, since the spacer 30 affects the orientation of the liquid crystal layer 29, the orientation of the liquid crystal layer 29 tends to be disturbed in the vicinity of the spacer 30. Accordingly, a region near the spacer 30 indicated by reference numeral “35” in FIGS. 7A and 7B becomes an unstable area related to the orientation of the liquid crystal layer 29, and light passing through the unstable area 35 is in an unintended direction. May be polarized. Comparing the spherical spacer 30 (see FIG. 7A) and the columnar spacer 30 (see FIG. 7B), the columnar spacer 30 is generally more unstable than the spherical spacer 30. The influence (see symbol “S” in FIGS. 7A and 7B) is small. That is, the unstable area 35 is determined according to the surface shape of the spacer 30, and the “spherical spacer 30 (having the tangent in the same direction as the light traveling direction)” has the “(tangent in the same direction as the light traveling direction). “A range in which light passes through the unstable area 35 (see reference sign“ S ”in FIGS. 7A and 7B)” tends to be larger than a “tapered columnar spacer 30 that does not have”.

  Thus, according to the columnar spacer 30 excellent in position fixability and light orientation, the alignment film (the first alignment film 27 and the second alignment film 28) is positioned even in an environment where an external force such as vibration is applied. In addition to being able to accurately perform the original function of securing the spacer, the polarization state of the light passing through the liquid crystal layer 29 can be accurately controlled. Therefore, the light control cell 10 (spacer 30 (refer FIG. 7)) which concerns on this embodiment mentioned above can be used suitably, for example in a window (for example, skylight of a house). In particular, a skylight of a house or the like is not necessarily a planar structure in design and may be required to have a curved structure. Even in such a case, according to the light control cell 10 (spacer 30) according to the above-described embodiment, at least one of the pair of polarizing plates (the first polarizing plate 21 and the second polarizing plate 22). It is possible to curve all or a part of one side, and it is also possible to curve other members (see reference numerals “23” to “30” in FIG. 2), and to curve the entire light control cell 10. Is also possible.

<Other configuration examples>
The specific configuration of the light control cell 10 is not limited to the above-described example, and a pair of film base materials (first film base material 23 and second film base material 24) and a pair of transparent electrodes (first transparent electrode 25 and The second transparent electrode 26), a pair of alignment films (a first alignment film 27 and a second alignment film 28), a plurality of spacers 30 and a liquid crystal layer 29 are also applicable to the other light control cell 10. It is.

  FIG. 8 is a diagram illustrating another example of a cross section of the light control cell 10. Each of the plurality of spacers 30 in this example has a multilayer structure (two-layer structure in this example), and is provided so as to penetrate the second alignment film 28 and the liquid crystal layer 29.

  That is, each spacer 30 includes a truncated cone-shaped core portion 40 and a covering portion 41 that covers at least a part of the core portion 40, and one of the pair of alignment films (in this example, the second alignment film 28) and It penetrates the liquid crystal layer 29. As shown in FIG. 8, the covering portion 41 of the present example covers the upper surface (upper bottom surface) of the core portion 40 on the first alignment film 27 side and the side surface (outer surface) of the core portion 40. It is interposed between the first alignment film 27, between the core part 40 and the liquid crystal layer 29, and between the core part 40 and the second alignment film 28. The covering portion 41 of this example is made of the same member as the second alignment film 28 and is formed integrally with the second alignment film 28. Therefore, “the covering portion 41 (see the dotted line portion in FIG. 10) interposed between the core portion 40 and the second alignment film 28” substantially constitutes a part of the second alignment film 28 and is actually covered. There is no interface between the portion 41 and the second alignment film 28. On the other hand, the lower surface (lower bottom surface) of the core portion 40 on the second transparent electrode 26 side is in contact with the second transparent electrode 26, and the covering portion 41 is not interposed between the core portion 40 and the second transparent electrode 26.

  Therefore, each spacer 30 in this example includes a first support surface 42 that is in two-dimensional contact with the other of the pair of alignment films (in this example, the first alignment film 27), and one of the pair of transparent electrodes ( In this example, it has the 2nd transparent electrode 26) and the 2nd support surface 43 which contacts two-dimensionally. The first support surface 42 is formed by the covering portion 41 and constitutes the first bottom portion 31 described above. The second support surface 43 is formed by the core portion 40 and the covering portion 41 (the covering portion 41 configured integrally with the second alignment film 28), and constitutes the above-described second bottom portion 32. In this example, the second support surface 43 (second bottom portion 32) of the spacer 30 is formed by the core portion 40 and the covering portion 41, and only a part of the second support surface 43 is formed by the core portion 40. However, the entire second support surface 43 may be formed by the core portion 40.

  Other configurations are the same as those of the dimming cell 10 shown in FIG. 2, and the same or similar components as those of the dimming cell 10 shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  According to the light control cell 10 of this example, the spacer 30 can be formed with high accuracy and easily based on the photolithography technique described later. In particular, the covering portion 41 of each spacer 30 is formed of the same member as the second alignment film 28, and the first alignment film 27 and the second alignment film 28 are formed of the same member, so that the covering portion 41 (first support) is formed. The surface 42) and the first alignment film 27 can be formed of the same member.

  Further, by providing each spacer 30 so as to penetrate the second alignment film 28 and the liquid crystal layer 29, the spacer 30 having excellent position fixability can be provided. That is, each spacer 30 is also supported by the second alignment film 28, and it is possible to effectively prevent each spacer 30 from moving due to an external force or the like. In the drawing, the first alignment film 27 and the second alignment film 28 are shown to have the same thickness as the liquid crystal layer 29. However, the actual first alignment film 27 and the second alignment film 28 are very It is thinly formed.

  Further, by making each spacer 30 have a multilayer structure, each spacer 30 can easily have various characteristics. For example, the core portion 40 of each spacer 30 is configured by a member having excellent rigidity, and the covering portion 41 is configured by a member that has a small influence on the liquid crystal layer 29, so that the surface characteristics are excellent while ensuring high yield strength performance. The spacer 30 can be realized. In the above example, each spacer 30 has a two-layer structure, but each spacer 30 may be composed of three or more layers.

  Also in this example, since the distance between the spacers 30 is not constant, the interference between the diffracted lights by the spacers 30 is not periodic, and the influence of the interference of the diffracted lights by the plurality of spacers 30 is reduced for visibility. Excellent observation light can be provided.

<The manufacturing method of the light control cell 10>
The method for manufacturing the light control cell 10 according to the present embodiment is not particularly limited, and the light control cell 10 can be manufactured using any bonding technique, photolithography technique, or the like. In particular, the tapered columnar spacer 30 can be preferably manufactured by a photolithography technique. When each spacer 30 is formed based on the photolithography technique, the resist is irradiated with light (exposure process) using a mask on which a pattern determined according to the arrangement of each spacer 30 is formed. The method of forming the above pattern in the mask is not particularly limited. For example, the lattice pattern can be obtained by shifting the XY coordinates of each lattice point (arrangement point of each spacer 30) by an arbitrary method on the basis of a square lattice pattern. The entire point (the entire spacer 30) can be randomly arranged.

  The present inventor changed the shift range of each lattice point of the square lattice in order to determine the arrangement of each spacer 30, and observed the light diffraction state for each of a plurality of types of “spacer 30 group” having different shift ranges. . Specifically, as shown in FIG. 9, in the square lattice, four lattice points (that is, “pairs”) arranged on a diagonal line centered on each lattice point (that is, “attention lattice point L1 (attention spacer 30)”)). One side of a square formed by the square lattice point L2 (diagonal spacer 30) is defined as “diagonal pitch P”. The limit R of the shift range regarding the XY coordinates of the target lattice point L1 (target spacer 30) is limited to 10% to 50% of this diagonal pitch P, and the target lattice point L1 (attention The arrangement of the spacers 30) was randomly shifted. The “attention spacer 30” here does not indicate only a specific spacer 30 among all the spacers 30, but each of all the spacers 30 is treated as the “attention spacer 30” here. That is, by determining the arrangement of each spacer 30 based on the position of the diagonal lattice point L2 (diagonal spacer 30) assigned to each spacer 30, the arrangement of all the spacers 30 is randomly shifted. . In this way, by shifting the arrangement of all the spacers 30 by using the “method of shifting the arrangement of the spacers 30 of interest based on the positions of the diagonal lattice points L2”, the entire spacers 30 can be randomly arranged. As a result, the diffraction phenomenon was somewhat conspicuous in “the range where the length of one side R of the shift range with respect to the XY coordinates of each spacer 30 is 10% or more and less than 30% of the diagonal pitch P”. When the length of one side R of the shift range limit R with respect to the X-Y coordinate of 30 is in the range of 30% or more and 50% or less of the diagonal pitch P, the diffraction phenomenon is hardly noticeable and good results are obtained.

  For example, a photosensitive resin (photo-curable resin) constituting the spacer 30 is coated on the second transparent electrode 26, and the tapered spacer 30 is formed from the photosensitive resin by a photolithography technique, and then the second transparent electrode is formed. A process of forming the second alignment film 28 on the electrode 26 and applying an alignment regulating force to the second alignment film 28 by rubbing or the like may be performed. In this case, the alignment imparting process is performed on the second alignment film 28 with the spacers 30 formed. Of the spacers 30, a “reverse tapered spacer 30” is formed in which the bottom portion (first bottom portion 31) on the first alignment film 27 side is larger than the bottom portion (second bottom portion 32) on the second alignment film 28 side. If the alignment imparting process is performed on the second alignment film 28 in a state where the second alignment film 28 is in a state, it may be difficult to impart sufficient orientation to the second alignment film 28 in the vicinity of the spacer 30. Therefore, from the viewpoint of imparting orientation to the second alignment film 28, the bottom portion (first bottom portion 31) on the first alignment film 27 side of each spacer 30 is the bottom portion (second bottom portion 32) on the second alignment film 28 side. A smaller “forward tapered spacer 30” is preferable.

  Next, a specific example will be described.

<Specific Example 1 (Comparative Example)>
The light control cell 10 of this example is the light control cell 10 which controls a transmitted light using a liquid crystal. A liquid crystal cell is produced by sandwiching the liquid crystal layer 29 between the liquid crystal alignment layer films (first alignment film 27 and second alignment film 28), and the liquid crystal cell is arranged in a parallel Nicol state (first polarization plate). The light control cell 10 of this example was produced by inserting | pinching with the board 21 and the 2nd polarizing plate 22).
Specifically, the light control cell 10 of this example has the same layer structure as the light control cell 10 shown in FIG. 2 (that is, the first polarizing plate 21, the second polarizing plate 22, the first film substrate 23, the second film). It includes a substrate 24, a first transparent electrode 25, a second transparent electrode 26, a first alignment film 27, a second alignment film 28, a liquid crystal layer 29, and a spacer 30 (particularly a spacer 30a).

  A TN liquid crystal is used for the liquid crystal layer 29 in this example, and the polarization plane of light passing therethrough is rotated by 90 ° in a state where an electric field does not act. A spacer 30 for keeping the thickness of the liquid crystal layer 29 (liquid crystal material) constant is a liquid crystal alignment layer film (specifically, the first alignment film 27 and the second alignment film 28 (strictly, the second transparent electrode 26)). ). The spacer 30 of this example is made of a transparent material and does not have a light shielding property against visible light. Each spacer 30 was arranged so that the distance to the other spacer 30 with the closest distance was constant. Moreover, as the 1st film base material 23 which supports the 1st transparent electrode 25, and the 2nd film base material 24 which supports the 2nd transparent electrode 26, it is a film-form resin base material (especially the film base material made from a polycarbonate in this example). It was used. For the liquid crystal alignment layer film, an electrode (first transparent electrode 25 and second transparent electrode 26) and an alignment layer (first alignment film 27 and second alignment film 28) are sequentially formed on a film material (base material). That was formed.

  When the light (light from the point light source) that has passed through the dimming cell 10 of this example is visually confirmed, the light from the point light source is affected by the interference of the diffracted light by each spacer 30, and light around the point light source. The interference area was generated.

<Specific Example 2 (Example)>
Each spacer 30 (all spacers 30) used in the light control cell 10 of this example was disposed so that the distance to the other spacer 30 with the closest distance was not constant. The other structure of the light control cell 10 of this example is the same as the above-mentioned specific example 1 (comparative example).

  When the light (light from the point light source) that has passed through the dimming cell 10 of this example is visually confirmed, interference of diffracted light by the spacers 30 with respect to the light from the point light source is obtained by arranging the spacers 30 at random. (Light intensity) was reduced to a level where it was not visible, and no light interference region was generated around the point light source.

  As described above, the influence of the interference of diffracted light by the plurality of spacers 30 is reduced by making the distance to the other spacer 30 closest to the closest distance at least part of the plurality of spacers 30 constant. Observation light with excellent visibility can be provided.

  The embodiments of the present invention are not limited to the above-described individual embodiments, but include various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the above-described contents. That is, various additions, changes, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 5 Dimming system 10 Dimming cell 12 Dimming controller 14 Sensor apparatus 16 User operation part 21 1st polarizing plate 22 2nd polarizing plate 23 1st film base material 24 2nd film base material 25 1st transparent electrode 26 2nd transparent Electrode 27 First alignment film 28 Second alignment film 29 Liquid crystal layer 30 Spacer 30a Spacer 30b Side 31 First bottom 32 Second bottom 34 Unit pattern 35 Unstable area 40 Unit pattern area

Claims (7)

A pair of polarizing plates;
A pair of film substrates disposed between the pair of polarizing plates;
A pair of electrodes disposed between the pair of polarizing plates;
A pair of alignment films disposed between the pair of electrodes;
A plurality of spacers supporting at least one of the pair of alignment films and in two-dimensional contact with at least one of the pair of alignment films;
And a liquid crystal layer disposed between the plurality of spacers between the pair of alignment films, wherein at least some of the plurality of spacers, rather than the most distance is the distance to the other spacer near constant ,
A dimming cell in which at least one of the pair of polarizing plates is curved in whole or in part . Each of the plurality of spacers is
A flat first bottom contacting one of the pair of alignment films;
The light control cell according to claim 1, further comprising a second bottom portion facing the first bottom portion.   The light control cell according to claim 1, wherein the plurality of spacers are made of a photocurable resin.   4. The plurality of spacers according to claim 1, wherein the plurality of spacers are configured by repeatedly arranging unit patterns configured by three or more spacers disposed in a predetermined relative positional relationship. 5. Dimming cell.   5. The light control cell according to claim 1, wherein each of the plurality of spacers has a tapered shape that tapers from one of the pair of alignment films toward the other.   The dimming cell according to any one of claims 1 to 5, wherein a taper angle of each of the plurality of spacers is in a range of 75 ° to 85 °. Each of the plurality of spacers is
A core part, and a covering part covering at least a part of the core part,
Penetrating one of the pair of alignment films and the liquid crystal layer,
A first support surface that is in two-dimensional contact with the other of the pair of alignment films; and a second support surface that is in two-dimensional contact with one of the pair of electrodes;
The first supporting surface is formed by the covering part, wherein at least a portion of the second supporting surface dimming cell according to any one of claims 1 to 6, which is formed by the core portion.

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