JP2017026678A - Dimmer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dimmer having a great number of gradations and capable of controlling light with multiple gradations.SOLUTION: A dimmer 10 comprises a light control part 12 and a movement part 14. The light control part 12 includes: a first polarizer 20; a second polarizer 22 disposed separately from the first polarizer 20; and three or more pattern phase difference films 30a, 30b, 30c disposed between the first polarizer and the second polarizer and having a plurality of slow axis directions in an identical plane. The first polarizer, the second polarizer, and each of the pattern phase difference films are disposed to be parallel to each other. The movement part moves at least one of the three or more pattern phase difference films relative to the pattern phase difference films in a parallel manner. At least two of the three or more pattern phase difference films have different retardation values. At least one of the three or more pattern phase difference film is relatively moved in parallel manner by the movement part, and thereby, the transmissivity of incident light, incident from the first polarizer or the second polarizer, is changed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light control device that adjusts incident light using a polarizer and a pattern retardation film to obtain transmitted light, and more particularly, to a light control device that can control light with a large number of gradations and multiple gradations.

  At present, various dimming methods using a polarizer have been proposed (Patent Documents 1 and 2). About the light control method using a polarizer, utilizing for the light control of the sunlight which injects from the window for buildings is also anticipated.

Patent Document 1 is composed of a laminate including at least one kind of film, a polarizer, and a light-transmitting substrate, and has a single plate transmittance T ₁ (λ)% and an orthogonal transmittance T ₂ (λ)% at a wavelength λ nm. However, 55% ≧ T ₁ (430) ≧ 38%, 60% ≧ T ₁ (590) ≧ 42.5%, 1.0 ≧ T ₁ (430) / T ₁ (590) ≧ 0.9, T ₂ A light-control polarizing plate satisfying (430)> 0.02% is described.
For a light transmissive substrate, a glass substrate, or a plastic substrate such as an acrylic plate, and for example, using a polarizing plate in which two polarizers having linear polarization ability and having absorption axes orthogonal to each other are laminated, It is described that the transmittance of incident light can be adjusted, that is, dimming can be performed according to the incident angle of light.

  Patent Document 2 includes a first uniform polarizer having a first transmission axis, a second uniform polarizer having a second transmission axis, and the first and second polarizers, And a first patterned wavelength retarder and a first and second polarizer comprising a first plurality of regions configured to change at least one of an optical axis, thickness or birefringence A second patterned wavelength retarder comprising a second plurality of regions located between and configured to change at least one of the optical axis, thickness, or birefringence, A variable transmission device is described in which the first or second wavelength retarder is configured to move linearly relative to the other of the first or second wavelength retarder. The first and second plurality of regions are configured to change the phase difference.

JP 2013-92707 A US Pat. No. 8,508,681

In patent document 1, it is possible to express the brightness of a glass plate by using a glass plate for a light-transmitting substrate. However, in Patent Document 1, only bright and dark colors are used, intermediate colors cannot be expressed, and the number of gradations is small.
In Patent Document 2, it is shown that patterning is performed by continuously changing the phase difference, but this is technically difficult and has not yet been put to practical use. It is difficult to realize intermediate gradations other than “dark state”, and multi-tone light control cannot be performed.

  It is an object of the present invention to provide a light control device that solves the above-described problems based on the prior art and can perform multi-tone light control with a large number of gradations.

  In order to achieve the above object, a first polarizer, a second polarizer spaced apart from the first polarizer, and a first polarizer and a second polarizer are arranged. Three or more pattern retardation films having a plurality of slow axis directions in the same plane, and the first polarizer, the second polarizer, and each pattern retardation film are arranged in parallel to each other. A dimming unit, and a moving unit that moves at least one of the three or more pattern phase difference films relatively in parallel to the other pattern phase difference film. Among the pattern retardation films, at least two pattern retardation films have different retardation values, and at least one of the three or more pattern retardation films is relatively parallel by the moving unit. To be incident from the first polarizer or the second polarizer. There is provided a light control device, characterized in that changing the transmittance of incident light.

Each pattern retardation film has two retardation regions whose slow axes are orthogonal to each other. When viewed from the first polarizer side, all of the pattern retardation films have their slow axes orthogonal or parallel. It is preferable to arrange them in a stacked manner.
The pattern retardation film is preferably formed of a composition containing a discotic liquid crystalline compound.

  Each of the first polarizer and the second polarizer is a linear polarizer or both are circular polarizers, and each pattern retardation film has a different retardation value at a wavelength of 550 nm. The sum of the retardation values of the pattern retardation film is preferably 220 nm to 320 nm, more preferably 230 to 300 nm, and particularly preferably 240 to 280 nm.

  According to the present invention, the number of gradations is large, multi-gradation light control can be performed, and intermediate gradations other than “bright state” and “dark state” can be realized with respect to incident light. .

(A) is a typical perspective view which shows the light modulation apparatus of embodiment of this invention, (b) is typical sectional drawing which shows the structure of a 1st polarizer and a 2nd polarizer, (c ) Is a schematic plan view showing the light control device of the embodiment of the present invention. It is a typical top view which shows the modification of the light modulation apparatus of embodiment of this invention. (A) is a schematic diagram which shows the 1st example of the moving part of the light modulation apparatus of embodiment of this invention, (b) is the 2nd example of the movement part of the light modulation apparatus of embodiment of this invention. It is a schematic diagram shown. (A) is a schematic diagram which shows the 1st example of the pattern phase difference film of the light modulation apparatus of embodiment of this invention, (b) is the 1st of the pattern phase difference film of the light modulation apparatus of embodiment of this invention. It is a schematic diagram which shows the example of 2. (A)-(d) is typical sectional drawing which shows an example of the light control of the light control apparatus of embodiment of this invention. It is a schematic plan view which shows the other example of the light modulation apparatus of embodiment of this invention. (A)-(d) is typical sectional drawing which shows the other example of the light control of the light control apparatus of embodiment of this invention. (A)-(d) is typical sectional drawing which shows the other example of the light control of the light control apparatus of embodiment of this invention. (A) And (b) is typical sectional drawing which shows the light control of a light control apparatus with two pattern phase difference films.

Hereinafter, based on a preferred embodiment shown in the accompanying drawings, a light control device of the present invention will be described in detail.
In the following, “to” indicating a numerical range includes numerical values written on both sides. For example, when ε is a numerical value α to a numerical value β, the range of ε is a range including the numerical value α and the numerical value β, and expressed by mathematical symbols, α ≦ ε ≦ β.
Unless otherwise specified, angles such as “45 °”, “parallel”, “vertical”, and “orthogonal” mean that the difference from the exact angle is within a range of less than 5 °. The difference from the exact angle is preferably less than 4 °, more preferably less than 3 °.
In addition, “same” includes an error range that is generally allowed in the technical field, and includes, for example, 99% or more, 95% or more, or 90% or more. In addition to “100%”, “all”, “any” or “entire surface” includes an error range generally allowed in the technical field, for example, 99% or more, 95% or more, or The case of 90% or more is included.
Visible light means light in the wavelength range of 380 to 750 nm.
In addition, when the measurement wavelength is not particularly described with respect to the in-plane retardation value Re, the thickness direction retardation value Rth, and the refractive index, the measurement wavelength is 550 nm. In-plane retardation is also simply referred to as retardation.

FIG. 1A is a schematic perspective view showing a light control device according to an embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view showing configurations of a first polarizer and a second polarizer, (C) is a schematic plan view which shows the light modulation apparatus of embodiment of this invention.
The light control device 10 shown in FIG. 1A adjusts the transmittance of incident light Li in multiple stages and adjusts the amount of transmitted light Lt in multiple stages. The light control device 10 has a large number of gradations and can realize multi-tone light control. Thereby, intermediate gradations other than the “bright state” and the “dark state” can be realized for the incident light Li.
The light control device 10 can be used, for example, for light control of sunlight incident from a building window, and can also be used for vehicles such as automobiles, partitions, and the like.
The incident light Li is not particularly limited, and varies depending on the environment in which the light control device 10 is placed, and may be sunlight or light such as a fluorescent lamp in an indoor environment.

The light control device 10 includes a light control unit 12, a moving unit 14, and a control unit 16. The moving unit 14 is controlled by the control unit 16.
The light control unit 12 includes a first polarizer 20, a second polarizer 22 that is spaced apart from the first polarizer 20, and a space between the first polarizer 20 and the second polarizer 22. And a phase difference portion 24 disposed in the.

The first polarizer 20 and the second polarizer 22 obtain polarized light from the incident light Li. The first polarizer 20 and the second polarizer 22 will be described in detail later.
Although the 1st polarizer 20 and the 2nd polarizer 22 can also be used alone, as shown in Drawing 1 (b), for example, you may provide in light transmissive substrate 26. Furthermore, the first polarizer 20 and the second polarizer 22 may have a protective film 28.
Here, the light-transmitting substrate 26 means that the light transmittance is at least 60% or more, preferably 75% or more, more preferably 80% or more, in the visible light wavelength region with a wavelength of 380 to 750 nm. Even more preferably, it is 85% or more.
The light transmittance is measured by using, for example, “plastic—how to obtain total light transmittance and total light reflectance” defined in JIS K 7375: 2008.

As the light-transmissive substrate 26, a glass plate used for a normal window, and a plastic substrate such as an acrylic plate, a polycarbonate plate, and a polystyrene plate can be used. Although the preferable range of the thickness of the light-transmitting substrate 26 varies depending on the application, it is generally 0.1 to 20 mm for a building window, and generally 1 to 20 for a vehicle window such as an automobile. 10 mm.
In the aspect in which the first polarizer 20 and the second polarizer 22 are layers formed by coating, the protective film 28 may be used as a support for the first polarizer and the second polarizer. Good. There is no restriction | limiting in particular as the protective film 28, The polymer film which contains as a main component various polymeric materials (it uses by the meaning containing both a polymer and resin) can be used. A film composed mainly of a polymer or resin that is excellent in light transmittance, mechanical strength, thermal stability, moisture shielding property, isotropic property and the like is preferable.

  As the protective film, it is preferable to use a film containing as a main component at least one selected from cellulose acylate, polyolefin, cyclic olefin polymer, acrylic resin, polyethylene terephthalate resin, and polycarbonate resin.

  Moreover, you may use a commercial item, for example, ZEONEX (trademark) by Nippon Zeon Co., Ltd., ZEONOR (trademark), Arton (trademark) by JSR Corporation, etc. can be used. Various commercially available cellulose acylate films can also be used.

  Moreover, as a protective film, the film formed by any method of a solution film forming method and a melt film forming method can also be used. The thickness of the film is preferably 10 to 1000 μm, more preferably 40 to 500 μm, and particularly preferably 40 to 200 μm.

  There is no restriction | limiting in particular about the optical characteristic of a protective film. From the viewpoint of reducing color change or light leakage when observed from an oblique direction, it is preferably an optically isotropic film, but is not limited thereto. Specifically, a film having an in-plane retardation value Re of 0 to 20 nm and an absolute value of Rth of 40 nm or less is preferable.

  In order to prevent the first polarizer 20 and the second polarizer 22 from being deteriorated by sunlight, any one of the layers positioned outside the polarizer including the light-transmitting substrate 26 and the protective film 28 is made of ultraviolet rays. It preferably contains an absorbent. The ultraviolet absorber may be added to any of the above-described layers, or may be formed as another layer. An example is an embodiment in which the protective film 28 includes an ultraviolet absorber. As the ultraviolet absorber, it is preferable to use an ultraviolet absorber that has an excellent ability to absorb ultraviolet rays having a wavelength of 370 nm or less and absorbs visible light having a wavelength of 400 nm or more as much as possible from the viewpoint of light transmittance. In particular, the transmittance at a wavelength of 370 nm is desirably 20% or less, preferably 10% or less, and more preferably 5% or less. Examples of such ultraviolet absorbers include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and ultraviolet absorbing groups as described above. Examples include, but are not limited to, polymeric ultraviolet absorbing compounds. Two or more kinds of ultraviolet absorbers may be used.

  For example, the usage-amount of a ultraviolet absorber is 0.1-5.0 mass parts with respect to 100 mass parts of main components of a protective film, Preferably it is 0.5-2.0 mass parts, More preferably, it is 0.8-2. 0.0 part by mass.

The phase difference unit 24 gives multistage phase differences to the light that has passed through the first polarizer 20 or the second polarizer 22. In the phase difference unit 24, the phase difference given to the light that has passed through the first polarizer 20 depends on the arrangement state of the transmission axis 21 of the first polarizer 20 and the transmission axis 23 of the second polarizer 22. It is determined. For example, if the transmission axis 21 of the first polarizer 20 and the transmission axis 23 of the second polarizer 22 are orthogonal to each other, the phase difference unit 24 zeroes the light that has passed through the first polarizer 20. It is preferable to give a phase difference in multiple steps within a range of ˜λ / 2. The definition of orthogonal is as described above.
Further, for example, when the first polarizer 20 is a circular polarizer and the second polarizer 22 is a circular polarizer, a phase difference of λ / 2 is given to light transmitted through the first polarizer 20. The light transmitted through the first polarizer 20 passes through the second polarizer 22. For this reason, in the phase difference part 24, it is preferable to give a phase difference to the light which passed the 1st polarizer 20 in multiple steps in the range of zero-(lambda) / 2.

The phase difference unit 24 includes, for example, three pattern phase difference films 30a to 30c arranged in parallel with each other. The first polarizer 20, the second polarizer 22, and the pattern retardation films 30a to 30c are arranged in parallel to each other.
In the light control device 10, the pattern retardation films 30a to 30c give a phase difference to incident light. Each pattern phase difference film 30a-30c functions as a phase difference plate.
In order to realize multi-gradation, each of the pattern retardation films 30a to 30c needs to have at least two different phase differences. Here, the phase difference is determined by the retardation value of each of the pattern phase difference films 30a to 30c. For this reason, among the three pattern retardation films 30a to 30c, at least two pattern retardation films have different retardation values.
As will be described later, if the pattern retardation films 30a to 30c all give the same phase difference, multiple gradations cannot be obtained.

The first phase difference region 31 and the second phase difference region 33 are respectively a phase difference region having a predetermined phase difference with respect to light transmitted through the polarizer (the first polarizer 20 and the second polarizer 22). It is. The first phase difference region 31 and the second phase difference region 33 are λ / 2 phase difference regions although the direction of the slow axis is different.
The λ / 2 phase difference region with respect to the light transmitted through the polarizer is a wavelength within the control wavelength region, preferably a length that is ½ of the center wavelength of the control wavelength region, or “center wavelength × n ± 1 / center wavelength”. A region having an in-plane retardation (phase difference value) of 2 (n is an integer of 0 or 1 or more) is intended. For example, when the center wavelength of the control wavelength region is 1000 nm, a retardation plate having a retardation of 500 nm, 1500 nm, 2500 nm, or the like can be used as the λ / 2 retardation plate.

More specifically, for example, when the light transmitted through the polarizer is light in the visible light region, the in-plane retardation values of the first phase difference region 31 and the second phase difference region 33 measured at a measurement wavelength of 550 nm. Certain Re (550) is preferably 220 nm ≦ Re (550) ≦ 320 nm, more preferably 230 ≦ Re (550) ≦ 300 nm, and still more preferably 240 nm ≦ Re (550) ≦ 280 nm.
The method for measuring retardation will be described in detail later.

Hereinafter, the pattern retardation films 30a to 30c will be described, but the pattern retardation film 30a will be described as an example, and description of the other pattern retardation films 30b and 30c will be omitted.
The pattern phase difference film 30a has a first phase difference region 31 and a second phase difference region 33, and the first phase difference region 31 and the second phase difference region 33 are alternately arranged in a stripe pattern in the same plane. Has been. The first phase difference region 31 has a slow axis 32, and the second phase difference region 33 has a slow axis 34. The pattern retardation film 30a has a plurality of slow axis directions in the same plane. The pattern retardation film 30a includes the first retardation region 31 and the second retardation region 33, but functions as providing the same retardation. The “slow axis” is an axis indicating the direction in which the refractive index is maximized.

As described above, the phase difference is determined by the retardation value. For this reason, the first retardation region 31 and the second retardation region 33 have the same retardation value.
The slow axis 32 of the first phase difference region 31 and the slow axis 34 of the second phase difference region 33 preferably have an angle difference of 70 to 110 °, and preferably have an angle difference of 80 to 100 °. More preferably, it has an angle difference of 90 °, that is, it is more preferable to be orthogonal. The orthogonal definition is as described above.
When the slow axis 32 of the first retardation region 31 and the slow axis 34 of the second retardation region 33 are orthogonal to each other, when all the pattern retardation films 30a to 30c are viewed from the first polarizer 20 side It is preferable that all of the pattern retardation films 30a to 30c are stacked so that the slow axes 32 and 34 are orthogonal or parallel to each other.
In this case, all the pattern retardation films 30a to 30c are arranged from the first polarizer 20 side by arranging the first retardation region 31 and the second retardation region 33 in the stacking direction. When viewing 30a to 30c, the slow axes 32 and 34 are arranged in parallel. In addition, after relatively moving at least one of the pattern retardation films 30a to 30c, the slow axis 32 and the slow axis 34 are orthogonal when viewed from the first polarizer 20 side. .

In the light control unit 12, the first polarizer 20, the second polarizer 22, and the pattern retardation films 30 a to 30 c are arranged to be stacked in parallel to each other.
In the light control device 10 shown in FIG. 1A, each of the first polarizer 20 and the second polarizer 22 is a linear polarizer, and the transmission axis 21 of the first polarizer 20 The transmission axes 23 of the second polarizer 22 are orthogonal. In this case, as described above, it is preferable that the phase difference unit 24 gives the phase difference to the light that has passed through the first polarizer 20 in multiple stages in the range of zero to λ / 2.
The transmission axis 21 of the first polarizer 20 and the transmission axis 23 of the second polarizer 22 are not limited to being orthogonal to each other, and the transmission axis 21 of the first polarizer 20 and the second polarization are not limited. The transmission axis 23 of the child 22 may be parallel. The definition of parallel is as described above.

In the light control device 10, the transmission axes 21 and 23 and the slow axes 32 and 34 are arranged, for example, in the configuration shown in FIG.
As shown in FIG. 2, the first polarizer 20 and the second polarizer 22 may both be circular polarizers. The circular polarizer will be described in detail later.

  Note that the number of pattern retardation films arranged in the phase difference portion 24 is not limited to three, and may be three or more, and may be four or five. The number of pattern phase difference films arranged in the phase difference unit 24 is appropriately determined according to the specifications of the light control device 10, and the number of gradations increases as the number of pattern phase difference films increases as will be described later. Will increase. The upper limit is not particularly limited, but when n pattern retardation films are used, it is necessary to separately move n-1 pattern retardation films, and the moving unit 14 becomes complicated. Moreover, the movement control of the pattern retardation film in the moving unit 14 becomes complicated. Furthermore, if the number of pattern retardation films is large, the light control device 10 is increased in size.

Hereinafter, the number of gradations that can be realized in the light control device 10 will be specifically described based on a configuration in which n pattern retardation films are stacked.
Hereinafter, the sum of the phase differences in the region where the plurality of pattern retardation films overlap is referred to as a total phase difference. The number of combinations of layers in the first retardation region 31 and the second retardation region 33 is 2 to the nth power (hereinafter referred to as 2 ^ n).
However, a combination in which the slow axis directions in the first retardation region 31 and the second retardation region 33 of all the pattern retardation films are interchanged gives the same transmittance only when the slow axis of the total phase difference is different by 90 °. Therefore, the maximum number of possible gradations is 2 ^ (n-1).
Arbitrary p number of pattern retardation films and q number of pattern retardation films (p, q ≧ 1, p + q <n) are selected from n sheets, and p total phase differences and q total phase differences are selected. If there are combinations with equal n, there are two combinations with the same total phase difference of n sheets, and the number of gradations is reduced.

In order to realize the maximum number of gradations 2 ^ (n-1), it is necessary that there is no combination of the pattern retardation films in which the total retardation is equal among the plurality of pattern retardation films.
Of course, the phase difference of each layer is different from each other, and the total phase difference obtained by adding a plurality of layers must be different from each other in any combination.
A combination in which n sheets are divided into two groups (p + q = n) and the total phase difference of each is equal, that is, a combination in which the total phase difference of n sheets is 0 has substantially no transmittance under crossed Nicols. A zero state is obtained, which is practically preferable.
In a plurality of pattern phase difference films, as a specific example in which there is no combination of pattern phase difference films in which the total phase difference is equal, the order of the phase difference ratio of each layer is as follows from the smallest.
A system that is 1: 2: 4: 8: ...: 2 ^ (k-1): ...: 2 ^ (n-2): 2 ^ (n-1) -1 is mentioned. In this case, the number of gradations is 2 ^ (n-1). Note that k is an integer.
The total phase difference in each gradation is 0, 2, 4, 6,..., 2 ^ n-6, 2 ^ n-4, 2 ^ n-2. At this time, the total phase difference of the 1st to (n-1) th layers is equal to the nth phase difference.

When the polarizing plates are linearly polarizing plates or circularly polarizing plates, the transmittance is maximized when the total phase difference of n sheets is λ / 2 (an integral multiple of λ / 2). A phase difference larger than that may give the same transmittance as a combination with a small phase difference, and the number of gradations decreases.
In order to avoid the overlap of transmittance and to obtain the maximum transmittance state, the total phase difference is obtained by combining all the n aligned regions in the slow axis direction (no cancellation). It is preferable to design the phase difference of each layer so that becomes λ / 2.

In the specific example described above, the phase difference of each layer is a combination shown below.
λ / (2 × (2 ^ n-2)), λ / (2 ^ n-2), λ / (2 ^ (n-1) -1), ..., λ / 4

The moving unit 14 moves at least one pattern phase difference film among the three pattern phase difference films 30 a to 30 c of the phase difference unit 24 relatively in parallel to the other pattern phase difference films. Is.
For example, the moving unit 14 moves the pattern retardation film 30c relatively in parallel. Further, the moving unit 14 may selectively move any one of the three pattern retardation films 30a to 30c, and relatively moves any two of them in parallel. It may be configured.
The moving unit 14 moves at least one pattern retardation film out of the three pattern retardation films 30a to 30c relatively in parallel to the other pattern retardation films, thereby The transmittance of incident light Li incident from the polarizer 20 or the second polarizer 22 can be changed.
The procedure for moving any one of the three pattern retardation films 30a to 30c in parallel, the amount of movement, and the timing are stored in the control unit 16 corresponding to the amount of transmitted light Lt. Thus, the moving unit 14 is controlled, and the pattern retardation films 30a to 30c are moved. Thereby, the light quantity of the transmitted light Lt is adjusted.

In addition, each pattern retardation film preferably has different retardation values at a wavelength of 550 nm from the viewpoint of increasing the number of gradations described above, and the sum of the retardation values of all the pattern retardation films is 220 nm to 320 nm. Preferably, it is 230 to 300 nm, more preferably 240 to 280 nm.
The pattern retardation films 30a to 30c will be described in detail later.

Here, FIG. 3A is a schematic diagram illustrating a first example of the moving unit of the light control device of the embodiment of the present invention, and FIG. 3B is a diagram of the moving unit of the light control device of the embodiment of the present invention. It is a schematic diagram which shows a 2nd example.
In the moving part 14, the moving mechanism 40 shown to Fig.3 (a) is used, for example. In the moving mechanism 40, a frame 44 is provided on a pair of guide rails 42 so as to be movable in the longitudinal direction of the guide rails 42. The frame 44 is provided with a pattern retardation film 30a. By moving the frame 44, the pattern retardation film 30a can be moved relatively parallel to the other pattern retardation films 30b and 30c.
Moreover, the moving mechanism 40a shown in FIG.3 (b) can also be used. In the moving mechanism 40a, the film 46 is attached to the pattern retardation film 30a, passed to the pair of rollers 48, and rotated to rotate the pattern retardation film 30a with respect to the other pattern retardation films 30b and 30c. Can be moved relatively in parallel.
The above-described moving mechanisms 40 and 40a have been described by taking the pattern retardation film 30a as an example. However, the movement mechanism 40 and 40a is not limited thereto, and the other pattern retardation films 30b and 30c can have the same configuration. .

The pattern phase difference film 30a shown in FIGS. 1A and 1B has a configuration in which the first phase difference region 31 and the second phase difference region 33 are arranged in a stripe shape, but is not limited thereto. is not.
Here, FIG. 4A is a schematic diagram showing a first example of the pattern retardation film of the light control device of the embodiment of the present invention, and FIG. 4B is a pattern of the light control device of the embodiment of the present invention. It is a schematic diagram which shows the 2nd example of a phase difference film.
4A and 4B, the same components as those of the pattern retardation film 30a shown in FIGS. 1A and 1B are denoted by the same reference numerals, and detailed description thereof is omitted.
For example, as shown to Fig.4 (a), as for the pattern phase difference film | membrane 30a, the 1st phase difference area | region 31 and the 2nd phase difference area | region 33 may be arrange | positioned at the grid | lattice form. Moreover, as shown in FIG.4 (b), the 1st phase difference area | region 31 and the 2nd phase difference area | region 33 may be arrange | positioned alternately. Even in this case, it is preferable that the slow axis 32 of the first phase difference region 31 and the slow axis 34 of the second phase difference region 33 are orthogonal to each other.
When the pattern retardation film 30a shown in FIGS. 4A and 4B is used, the other pattern retardation films 30b and 30c have the same configuration.

Next, light control by the light control device 10 will be described.
5A to 5D are schematic cross-sectional views illustrating an example of light control of the light control device according to the embodiment of the present invention.
5A to 5D, the same components as those of the light control device 10 illustrated in FIGS. 1A and 1B are denoted by the same reference numerals, and detailed description thereof is omitted. 5A to 5D show the first state to the fourth state as will be described later. This corresponds to the first state to the fourth state in Tables 1 to 3 below. doing.

5A to 5D, the transmission axis 21 of the first polarizer 20 and the transmission axis 23 of the second polarizer 22 are orthogonal to each other, and the incident light Li from the first polarizer 20 side. Is incident, and the light that has passed through the first polarizer 20 is given by the phase difference unit 24. When the phase difference of λ / 2 is given in absolute value, the transmitted light Lt from the second polarizer 22 is brightest. It becomes a state.
When the phase difference is not given to the light that has passed through the first polarizer 20 by the phase difference unit 24, that is, when the phase difference is zero, the light that has passed through the first polarizer 20 is theoretically In this case, the light cannot pass through the second polarizer 22 and is in a dark state. In the light control device 10, the transmittance of the incident light Li can be changed according to the degree of the phase difference given by the phase difference unit 24, that is, the light amount of the transmitted light Lt can be changed, thereby realizing multiple gradations. Can do.
5A to 5D, the sign of “+” and the sign of “−” shown in the pattern retardation films 30a to 30c indicate that the direction of the slow axis is different, and the sign of “+”. And the sign of “−”, the slow axis is orthogonal. The sign “+” corresponds to the first phase difference region 31, and the sign “−” corresponds to the second phase difference region 33.

5A to 5D, the pattern phase difference film 30a gives a phase difference of λ / 4, the pattern phase difference film 30b gives a phase difference of λ / 6, and the pattern phase difference film 30c becomes λ. When a phase difference of / 12 is given, as shown in FIG. 5A, the pattern retardation films 30a to 30c are aligned with "+" signs and "-" signs in the stacking direction. In the first state of overlapping, the light passing through the first polarizer 20 can be given a phase difference of λ / 2 in absolute value, and the transmitted light Lt from the second polarizer 22 The light intensity can be maximized and the light can be brightened. This bright state is described as “pretty bright” in Table 1 below.
As shown in FIG. 5B, the moving unit 14 moves the pattern retardation film 30c from the first state of FIG. 5A by one phase difference region in parallel to the second state. . At this time, the overlapping combination is changed in the pattern phase difference films 30a to 30c, and the phase difference unit 24 gives a phase difference of λ / 3 as an absolute value. In the second state, the amount of transmitted light Lt is reduced as compared with the first state. In Table 1 below, “bright” is indicated.

As shown in FIG. 5 (c), the moving unit 14 moves the pattern retardation film 30b from the first state of FIG. 5 (a) by one phase difference region in parallel to the third state. . At this time, the overlapping combination is changed in the pattern phase difference films 30a to 30c, and the phase difference unit 24 gives a phase difference of λ / 6 in absolute value. In the third state, the amount of transmitted light Lt is reduced as compared with the second state. In Table 1 below, “slightly dark” is indicated.
As shown in FIG. 5D, the moving unit 14 moves the pattern retardation films 30b and 30c in parallel in one retardation region from the first state of FIG. To. At this time, the overlapping combination is changed in the pattern retardation films 30a to 30c, and the phase difference unit 24 does not give a phase difference. That is, the phase difference is zero. When the phase difference is zero, light that has passed through the first polarizer 20 cannot in principle pass through the second polarizer 22, and in the fourth state, in principle, the transmitted light Lt is not transmitted. Zero. In Table 1 below, “dark” is indicated.

In this way, by moving the pattern retardation films 30a to 30c in parallel, the overlapping combination of the pattern retardation films 30a to 30c can be changed, so that the phase difference can be divided into four stages. It is possible to realize four levels of multi-gradation including this state. That is, the light control device 10 can obtain four gradations. In addition, since the contrast between light and dark at the time of driving becomes low, it becomes difficult to see the stripe pattern.
Table 1 below shows the phase differences and gradations in the first state to the fourth state shown in FIGS. As the state changes from the first state shown in FIGS. 5A to 5D to the fourth state, the amount of transmitted light Lt decreases. That is, it becomes dark. Note that the phase difference shown in Table 1 below is the phase difference in the region X1 shown in FIGS. The phase difference of the region X2 adjacent to the region X1 is the same in absolute value as the phase difference of the region X1.

  5A to 5D, the pattern phase difference film 30a gives a phase difference of λ / 4, the pattern phase difference film 30b gives a phase difference of λ / 8, and the pattern phase difference film 30c becomes λ. When a phase difference of / 8 is given, as shown in Table 2 below, the phase difference can be made into three stages of λ / 2, λ / 4, and zero, and a multi-gradation can be realized. . In this case, among the pattern phase difference films 30a to 30c, the pattern phase difference film 30b and the pattern phase difference film 30c give the same phase difference. Since the second state and the third state are the same amount of transmitted light Lt, the operation of the light control device 10 may be one of the second state and the third state.

  5A to 5D, when the pattern retardation films 30a to 30c are all the same as those that give a phase difference of λ / 6, as shown in Table 3 below, the phase difference is λ / 2, Only two stages of λ / 6 are possible, and multi-gradation cannot be realized. If the number of pattern retardation films is simply increased to 3, multi-gradation cannot be realized.

Next, the light control device 10a having four pattern retardation films will be described.
FIG. 6 is a schematic plan view showing another example of the light control device according to the embodiment of the present invention. FIGS. 7A to 7D and FIGS. 8A to 8D are schematic cross-sectional views showing other examples of light control of the light control device according to the embodiment of the present invention.
6 and FIGS. 7A to 7D and FIGS. 8A to 8D, the same components as those of the light control device 10 shown in FIGS. 1A and 1B are denoted by the same reference numerals. Detailed description thereof will be omitted.

The light control device 10a shown in FIG. 6 has the same configuration as the light control device 10 shown in FIGS. 1A and 1B except that it has four pattern retardation films 30a to 30d. Detailed explanation is omitted. The pattern retardation film 30d has the same configuration as the above-described pattern retardation films 30a to 30c.
Also in the light control device 10a, similarly to the light control device 10, the transmittance of the incident light Li from the first polarizer 20 side can be changed in the phase difference unit 24, and multiple gradations can be realized. . Since the light control device 10a has a larger number of pattern retardation films than the light control device 10, it is possible to increase the gradation. The light control device 10a can obtain 8 gradations. In addition, since the contrast between light and dark at the time of driving becomes low, the stripe pattern becomes even more difficult to see.

Next, light control by the light control device 10a will be described.
7A to 7D and FIGS. 8A to 8D, the transmission axis 21 of the first polarizer 20 and the transmission axis 23 of the second polarizer 22 are orthogonal to each other. The incident light Li incident from the side of the first polarizer 20 has the largest amount of transmitted light Lt from the second polarizer 22 when a phase difference of λ / 2 is given by the phase difference unit 24. It becomes the brightest bright state.
In addition, when no phase difference is given by the phase difference unit 24, that is, when the phase difference is zero, light that has passed through the first polarizer 20 is transmitted through the second polarizer 22 in principle. I can't do it and it's dark. In the light control device 10, the transmittance of the incident light Li can be changed according to the degree of the phase difference given by the phase difference unit 24, that is, the light amount of the transmitted light Lt can be changed, thereby realizing multiple gradations. Can do.
7A to 7D and FIGS. 8A to 8D, the sign of “+” and the sign of “−” shown in the pattern retardation films 30a to 30d indicate the direction of the slow axis. The slow axis is orthogonal to the sign of “+” and the sign of “−”. The sign “+” corresponds to the first phase difference region 31, and the sign “−” corresponds to the second phase difference region 33.

7A to 7D and FIGS. 8A to 8D, the pattern retardation film 30a gives a phase difference of λ / 4, and the pattern retardation film 30b has a phase difference of λ / 7. When the pattern retardation film 30c is provided with a phase difference of λ / 14 and the pattern retardation film 30d is provided with a phase difference of λ / 28, as shown in FIG. When the films 30 a to 30 d are in the first state in which the signs of “+” are aligned in the stacking direction and the signs of “−” are aligned, they are absolute with respect to the light that has passed through the first polarizer 20. A phase difference of λ / 2 can be given by value, and the transmitted light Lt can be maximized from the second polarizer 22. In Table 4 below, it is described as “pretty bright”.
As shown in FIG. 7 (b), the moving unit 14 moves the pattern retardation film 30d from the first state of FIG. 7 (a) by one phase difference region in parallel to the second state. . At this time, the overlapping combination is changed in the pattern retardation films 30a to 30d, and the phase difference unit 24 gives a phase difference of 3λ / 7 as an absolute value. In the second state, the amount of transmitted light Lt is reduced as compared with the first state. In Table 4 below, “bright” is indicated.

As shown in FIG. 7 (c), the moving unit 14 moves the pattern retardation film 30c from the first state of FIG. 7 (a) by one phase difference region in parallel to the third state. . At this time, the overlapping combination is changed in the pattern phase difference films 30a to 30d, and the phase difference unit 24 gives a phase difference of 5λ / 14 in absolute value. In the third state, the amount of transmitted light Lt is reduced as compared with the second state. In Table 4 below, “bright” is indicated.
As shown in FIG. 7D, the moving unit 14 moves the pattern retardation films 30c and 30d in parallel by one phase difference region from the first state of FIG. To. At this time, the overlapping combination is changed in the pattern phase difference films 30a to 30d, and the phase difference unit 24 gives a phase difference of 2λ / 7 as an absolute value. In the fourth state, the amount of transmitted light Lt is reduced as compared with the third state. In Table 4 below, “slightly dark” is indicated.

As shown in FIG. 8A, the moving unit 14 moves the pattern retardation film 30b by one phase difference region in parallel from the first state of FIG. 7A to the fifth state. . At this time, the overlapping combination is changed in the pattern retardation films 30a to 30d, and the phase difference unit 24 gives a phase difference of 3λ / 14 in absolute value. In the fifth state, the amount of transmitted light Lt is reduced as compared with the fourth state. In Table 4 below, “slightly dark” is indicated.
As shown in FIG. 8B, the moving unit 14 moves the pattern retardation films 30b and 30d in parallel by one phase difference region from the first state of FIG. To. At this time, the overlapping combination changes in the pattern retardation films 30a to 30d, and the phase difference unit 24 gives a phase difference of λ / 7 in absolute value. In the sixth state, the amount of transmitted light Lt is reduced as compared with the fifth state. In Table 4 below, “slightly dark” is indicated.
As shown in FIG. 8C, the moving unit 14 moves the pattern retardation films 30b and 30c in parallel by one phase difference region from the first state of FIG. To. At this time, the overlapping combination changes in the pattern retardation films 30a to 30d, and the phase difference unit 24 gives a phase difference of λ / 14 in absolute value. In the seventh state, the amount of transmitted light Lt is reduced as compared with the sixth state. In Table 4 below, “dark” is indicated.
As shown in FIG. 8D, the moving unit 14 moves the pattern retardation films 30b, 30c, and 30d in parallel by one phase difference region from the first state of FIG. To the state. At this time, the overlapping combination changes in the pattern retardation films 30a to 30d, and the phase difference unit 24 does not give a phase difference. That is, the phase difference is zero. When the phase difference is zero, light that has passed through the first polarizer 20 cannot in principle pass through the second polarizer 22, and in the eighth state, in principle, the transmitted light Lt is not transmitted. Zero. In Table 4 below, “dark” is indicated.

In this way, by moving the pattern retardation films 30a to 30d in parallel, the overlapping combination of the pattern retardation films 30a to 30d can be changed, so that the phase difference can be divided into eight stages. It is possible to realize 8 levels of multi-gradation and 8 gradations including the above state.
Table 4 below shows the phase differences and gradations of the first to sixth states shown in FIGS. 7 (a) to (d) and FIGS. 8 (a) to (d). As the state changes from the first state shown in FIGS. 7A to 7D and FIGS. 8A to 8D to the sixth state, the amount of transmitted light Lt decreases. That is, it becomes dark. The phase differences shown in Table 4 below are the phase differences in the region X1 shown in FIGS. 7 (a) to (d) and FIGS. 8 (a) to (d). The phase difference of the region X2 adjacent to the region X1 is the same in absolute value as the phase difference of the region X1.

  7A to 7D and FIGS. 8A to 8D, the pattern retardation film 30a gives a phase difference of λ / 4, and the pattern retardation film 30b has a phase difference of λ / 8. As shown in Table 5 below, when the pattern retardation film 30c gives a phase difference of λ / 12 and the pattern retardation film 30d gives a phase difference of λ / 24, the phase difference is λ / 2, 5λ / 12, λ / 3, λ / 4, λ / 6, λ / 12, and zero, and can achieve multi-gradation. Since the fourth state and the fifth state are the same amount of transmitted light Lt, the operation of the light control device 10a may be any one of the fourth state and the fifth state.

7A to 7D and FIGS. 8A to 8D, the pattern retardation film 30a gives a phase difference of λ / 4, and the pattern retardation film 30b has a phase difference of λ / 8. When the pattern retardation films 30c and 30d are provided with a phase difference of λ / 16, the phase differences are λ / 2, 3λ / 8, λ / 4, and λ / 8 as shown in Table 6 below. , Zero can be made into five stages, and multi-gradation can be realized. In this case, among the pattern retardation films 30a to 30d, the pattern retardation film 30c and the pattern retardation film 30d give the same retardation.
The second state and the third state are the same amount of transmitted light Lt, and the fourth state and the fifth state are the same amount of transmitted light Lt. The sixth state and the seventh state are the same amount of transmitted light Lt. For this reason, as operation | movement of the light modulation apparatus 10a, what is necessary is just to be either one among a 2nd state and a 3rd state, and if it is set as either one among a 4th state and a 5th state. Good. Further, any one of the sixth state and the seventh state may be set.

  7A to 7D and FIGS. 8A to 8D, the pattern retardation film 30a gives a phase difference of λ / 4, and the pattern retardation films 30b to 30d are all λ / 12. If the phase difference is the same as that giving the phase difference, as shown in Table 7 below, the phase difference can be set in four stages of λ / 2, λ / 3, λ / 6, and zero, thereby realizing multi-gradation. be able to. In this case, among the pattern retardation films 30a to 30d, the pattern retardation film 30b to the pattern retardation film 30d give the same retardation. The second state, the third state, and the fifth state are the same amount of transmitted light Lt. The fourth state, the sixth state, and the seventh state are the same amount of transmitted light Lt. For this reason, as operation | movement of the light modulation apparatus 10a, what is necessary is just to be any one among a 2nd state, a 3rd state, and a 5th state. Further, any one of the fourth state, the sixth state, and the seventh state may be set.

Next, the light control device 100 having two pattern retardation films will be described.
FIGS. 9A and 9B are schematic cross-sectional views showing light control of a light control device having two pattern retardation films.
9A and 9B, the same components as those of the light control device 10 shown in FIGS. 1A and 1B are denoted by the same reference numerals, and detailed description thereof is omitted.

The light control device 100 shown in FIGS. 9A and 9B is the same as the light control device 10 shown in FIGS. 1A and 1B except that it has two pattern retardation films 30a and 30b. Since it is a structure, the detailed description is abbreviate | omitted.
In the light control device 100, when the two pattern retardation films 30 a and 30 b are all the same as those that give a phase difference of λ / 4, as shown in Table 8 below, the phase difference is λ / 2, There are two levels of zero, and only two gradations are possible: a bright state and a dark state.
Furthermore, since the two pattern phase difference films 30a and 30b can only have two gradations of a bright state and a dark state, the contrast variation during driving is large, and stripes with large contrast are generated. On the other hand, since the amount of transmitted light can be made multi-tone by providing three or more pattern retardation films as described above, the change in the amount of transmitted light is reduced when the pattern retardation film is moved. it can. That is, it is possible to weaken the contrast fluctuation during driving. For this reason, generation | occurrence | production of stripes with a large contrast can be suppressed.

(First polarizer and second polarizer)
As the first polarizer 20 and the second polarizer 22, so-called linear polarizers having a function of converting natural light into specific linearly polarized light are used. In particular, in FIG. 1A, as the first polarizer 20 and the second polarizer 22, absorption linear polarizers are used.
The type of the absorption linear polarizer is not particularly limited, and a known absorption polarizer can be used. For example, a dye-based polarization using an iodine-based polarizing film or a dichroic dye (dichroic organic dye) Either a film or a polyene polarizing film can be used. The iodine-based polarizing film and the dye-based polarizing film are generally produced by adsorbing iodine or a dichroic dye to polyvinyl alcohol and stretching it.
Note that, as the first polarizer 20 and the second polarizer 22, a reflective linear polarizer may be used in addition to the absorption linear polarizer.
As the reflective linear polarizer, a known one can be used. For example, a polarizer in which thin films having different birefringence are laminated (described in Japanese Patent Publication No. 9-506837, etc. As a commercial product. 3M, trade name: DBEF), wire grid polarizers (commercially available products are, for example, Edmund Optics Wire Grid Polarization Filter 50 × 50, NT46-636, etc.).
Note that the reflective linear polarizer has a property of transmitting a polarized light component in a first direction and reflecting a polarized light component in a direction orthogonal to the first direction in incident light. That is, when non-polarized light is incident from one side of the first polarizer 20 and the second polarizer 22, linearly polarized light is obtained from the other side. By using such a reflective polarizer, a predetermined polarization component is reflected, light absorption is suppressed, and heat shielding properties, durability, and light shielding properties are improved.

The wavelength range of light transmitted or reflected by the first polarizer 20 and the second polarizer 22 (hereinafter also referred to as “control wavelength range”) is not particularly limited, and may be within the wavelength range of infrared light. In the wavelength range of visible light or in the wavelength range of ultraviolet light, the wavelength range of infrared light and visible light, the wavelength range of visible light and ultraviolet light, or infrared light, visible light and It may be a wavelength range that spans the wavelength range of ultraviolet light. In particular, from the viewpoint that the heat shielding property and durability of the light control device are more excellent, it is preferably in the wavelength range of visible light or near infrared light.
In addition, infrared rays (infrared light) are electromagnetic waves in a wavelength region longer than visible rays and shorter than radio waves. Near-infrared light is generally an electromagnetic wave having a wavelength range of more than 750 nm and not more than 2500 nm. Visible light is light having a wavelength visible to the human eye among electromagnetic waves, and indicates light having a wavelength range of 380 nm to 750 nm. Ultraviolet rays are electromagnetic waves in a wavelength range shorter than visible light and longer than X-rays. The ultraviolet light may be light in a wavelength region that can be distinguished from visible light and X-rays, and is, for example, light in a wavelength range of 10 nm or more and less than 380 nm.

As the first polarizer 20 and the second polarizer 22, a right circular polarizer and a left circular polarizer can be used. Hereinafter, the right circular polarizer will be mainly described.
The right circular polarizer is a polarizer having a function of selectively transmitting right circularly polarized light in a specific wavelength range. That is, the first polarizer 20 and the second polarizer 22 selectively transmit right circularly polarized light to the other side surface among light in a specific wavelength region (natural light, non-polarized light) incident from one side surface. Can do.
Here, among the circularly polarized light, when viewed from the light traveling direction, the clockwise light is referred to as right circularly polarized light, and the counterclockwise light is referred to as left circularly polarized light. The right circularly polarized light and the left circularly polarized light are the same except that the directions are different. The left circular polarizer is a polarizer having a function of selectively transmitting left circular polarized light in a specific wavelength range.

The specific wavelength range selectively transmitted by the right circular polarizer and the left circular polarizer may be the same as that described as the control wavelength range in the first polarizer 20 and the second polarizer 22 described above. .
As the right circular polarizer and the left circular polarizer, known ones can be used. For example, a reflective circular polarizer using selective reflection characteristics by a cholesteric liquid crystal or a ferroelectric liquid crystal is used.
In addition, a circular polarizer using cholesteric liquid crystal exhibits a cholesteric property by adding a predetermined amount of a chiral agent that induces right-handed twist or left-handed twist to a polymerizable liquid crystalline compound, thereby producing right and left circularly polarized light components. Can be a circular polarizer that selectively reflects and transmits the remaining circularly polarized light component.

Hereinafter, the mechanism through which light is transmitted when a circular polarizer is used will be described using the right circular polarizer as an example.
When both the first polarizer 20 and the second polarizer 22 are right circular polarizers, the pattern retardation film 30a is λ / 4 in the configuration of the light control device 10 shown in FIG. When the phase difference film, the pattern phase difference film 30b gives a phase difference of λ / 6, and the pattern phase difference film 30c gives a phase difference of λ / 12, the first polarizer 20 is obtained. Of the incident light, only the right circularly polarized light passes through the first polarizer 20. Next, the right circularly polarized light transmitted through the first polarizer 20 is converted into linearly polarized light by the pattern retardation film 30a. Next, the linearly polarized light transmitted through the pattern phase difference film 30a is given a total phase difference of λ / 4 by the pattern phase difference film 30b and the pattern phase difference film 30c, and is converted into right circularly polarized light again. Next, the right circularly polarized light that has passed through the pattern retardation film 30 b passes through the second polarizer 22.
Each of the first polarizer 20 and the second polarizer 22 is not limited to a configuration using a right circular polarizer, and both may use a left circular polarizer, and further, a right circular polarizer. And a left circular polarizer. That is, in the present invention, so-called circular polarizers (right circular polarizer and left circular polarizer) may be used as the first polarizer and the second polarizer.

Next, the pattern retardation films 30a to 30d will be described.
The pattern phase difference films 30a to 30d include a first phase difference region 31 and a second phase difference region 33 whose in-plane slow axis directions are different from each other, and the first phase difference region 31 and the second phase difference region 33 are the same. In the plane, they are alternately arranged in stripes with the same width (pitch).
FIGS. 1A and 1B show a mode in which the first phase difference region 31 and the second phase difference region 33 are both arranged in stripes having the same width (pitch). However, the present invention is limited to this mode. Is not to be done.

  The material which comprises pattern phase difference film 30a-30d is not restrict | limited in particular, For example, a liquid crystalline compound is mentioned. More specifically, an optically anisotropic layer obtained by forming a low-molecular liquid crystalline compound in a nematic alignment in a liquid crystal state and then fixing by photocrosslinking or thermal crosslinking, and a high molecular liquid crystalline compound in a nematic alignment in a liquid crystal state. An optically anisotropic layer obtained by fixing the orientation by cooling after formation can also be used. The pattern retardation films 30a to 30d are preferably formed of a composition containing a discotic liquid crystalline compound.

In general, liquid crystal compounds can be classified into rod-shaped types (rod-shaped liquid crystalline compounds) and disc-shaped types (discotic liquid-crystalline compounds) based on their shapes. Furthermore, there are low molecular type and high molecular type, respectively. Polymer generally refers to a polymer having a degree of polymerization of 100 or more (Polymer Physics / Phase Transition Dynamics, Masao Doi, 2 pages, Iwanami Shoten, 1992). In the present invention, any liquid crystalline compound can be used. Two or more kinds of rod-like liquid crystalline compounds, two or more kinds of discotic liquid crystalline compounds, or a mixture of a rod-like liquid crystalline compound and a discotic liquid crystalline compound may be used.
In addition, as the rod-like liquid crystal compound, for example, those described in claim 1 of JP-A-11-513019 and paragraphs [0026] to [0098] of JP-A-2005-289980 can be preferably used. As the discotic liquid crystalline compound, for example, those described in paragraphs [0020] to [0067] of JP-A-2007-108732 and paragraphs [0013] to [0108] of JP-A-2010-244038 are preferable. Although it can be used, it is not limited to these.

The pattern retardation film can more preferably be formed using a rod-like liquid crystal compound or a discotic liquid crystal compound having a polymerizable group because the change in temperature or change in humidity can be reduced. The liquid crystalline compound may be a mixture of two or more types, and in that case, at least one preferably has two or more polymerizable groups.
That is, the pattern retardation film is preferably a layer formed by fixing a rod-like liquid crystalline compound or a discotic liquid crystalline compound having a polymerizable group by polymerization or the like. It is not necessary to show liquid crystallinity.
The kind of the polymerizable group contained in the discotic liquid crystalline compound and the rod-like liquid crystalline compound is not particularly limited, and a functional group capable of addition polymerization reaction is preferable, and a polymerizable ethylenically unsaturated group or a ring polymerizable group is preferable. More specifically, a (meth) acryloyl group, a vinyl group, a styryl group, an allyl group, etc. are mentioned preferably, and a (meth) acryloyl group is more preferable.

Examples of the method for forming the above-described pattern retardation film include the following preferred embodiments. However, the present invention is not limited thereto, and a known method can be adopted. For example, as described in JP-A-2014-89431 A method is mentioned. A form using a photo-alignment film is also preferable.
The photo-alignment film is a film having a property of causing anisotropy in the film by irradiation with polarized light or non-polarized light and causing alignment regulating force in the liquid crystal. For example, a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter sometimes referred to as “photoalignment film forming composition”) is applied to a substrate, and polarized light (preferably polarized UV) Can be used to obtain a photo-alignment film imparted with an alignment regulating force. The photoreactive group refers to a group that generates liquid crystal alignment ability when irradiated with light (light irradiation). Specifically, it causes photoreactions that are the origin of liquid crystal alignment ability, such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photolysis reaction caused by light irradiation. is there. Specifically, the photoreactive group includes a group having an azobenzene structure (skeleton), a group having a hydrazono-β-ketoester structure (skeleton), a group having a stilbene structure (skeleton), and a spiropyran structure (skeleton). Groups and the like.

Next, a method for measuring the in-plane retardation value Re (hereinafter simply referred to as Re) and the thickness direction retardation value Rth (hereinafter simply referred to as Rth) will be described.
Re is measured by making light having a measurement wavelength (nm) incident in the normal direction of the film in an AxoScan manufactured by Axometrics.

When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth is calculated by the following method.
Rth is the Re and the slow axis and the fast axis in the plane are inclined axes (rotating axes), and light of the measurement wavelength (nm) is incident from the inclined directions of −45 ° to + 45 ° in 5 ° steps. A total of 19 points are measured, and AxoScan calculates based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value. The average value of the values calculated for the slow axis and the fast axis is defined as Rth of the film.

  In addition, the retardation value is measured from two inclined directions with the slow axis as the tilt axis (rotary axis) (in the case where there is no slow axis, the arbitrary direction in the film plane is the rotary axis), Rth can also be calculated from the following formula (21) and formula (22) based on the value, the assumed value of the average refractive index, and the input film thickness value.

  In the above formula (21), Re (θ) represents an in-plane retardation value in a direction inclined by an angle θ from the normal direction. In the above formulas (21) and (22), nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, and nz represents nx and ny. Represents the refractive index in the direction perpendicular to. d represents the film thickness of the film.

In the above-described measurement, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59).
The AxoScan calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

  The present invention is basically configured as described above. The light control device of the present invention has been described in detail above. However, the present invention is not limited to the above-described embodiment, and various modifications or changes may be made without departing from the spirit of the present invention. It is.

The features of the present invention will be described more specifically with reference to the following examples. The materials, reagents, used amounts, substance amounts, ratios, processing details, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Accordingly, the scope of the present invention should not be construed as being limited by the specific examples shown below.
In this example, dimmers of Examples 1 to 3 and Comparative Example 1 described later were manufactured. Configurations used in the light control devices of Examples 1 to 3 and Comparative Example 1 described later will be described.

<Preparation of transparent support A>
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acylate solution A.
────────────────────────────────────
Composition of Cellulose Acylate Solution A────────────────────────────────────
Cellulose acetate having a substitution degree of 2.86 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 300 parts by weight Methanol (second solvent) ) 54 parts by mass 1-butanol 11 parts by mass ─────────────────────────────────────

The following composition was charged into another mixing tank, stirred while heating to dissolve each component, and an additive solution B was prepared.
────────────────────────────────────
Composition of additive solution B ─────────────────────────────────────
The following compound B1 (Re reducing agent) 40 parts by mass The following compound B2 (wavelength dispersion controlling agent) 4 parts by mass Methylene chloride (first solvent) 80 parts by mass Methanol (second solvent) 20 parts by mass ──────── ────────────────────────────

<< Preparation of transparent cellulose acetate support >>
A dope was prepared by adding 40 parts by mass of the additive solution B to 477 parts by mass of the cellulose acylate solution A and stirring sufficiently. The dope was cast from a casting port onto a drum cooled to 0 ° C. The film is peeled off at a solvent content of 70% by mass, and both ends in the width direction of the film are fixed with a pin tenter (the pin tenter described in FIG. 3 of JP-A-4-1009), and the solvent content is 3-5% by mass. In this state, the film was dried while maintaining an interval at which the stretching ratio in the transverse direction (direction perpendicular to the machine direction) was 3%. Then, it dried further by conveying between the rolls of a heat processing apparatus, and produced the 60-micrometer-thick cellulose acetate protective film (henceforth transparent support body A). Transparent support A did not contain an ultraviolet absorber, Re (550) was 0 nm, and Rth (550) was 12.3 nm.

<< Preparation of transparent support A subjected to alkali saponification treatment >>
The transparent support A produced above was passed through a dielectric heating roll having a temperature of 60 ° C., and the film surface temperature was raised to 40 ° C. Then, an alkali solution having the composition shown below was applied to one side of the film as # 6. It apply | coated continuously with the wire bar, heated to 110 degreeC, and conveyed for 10 second under the steam type far-infrared heater by Noritake Company Limited. Subsequently, 3 ml / m ^{2 of} pure water was applied using the same # 6 wire bar. Subsequently, washing with a fountain coater and draining with an air knife were repeated three times, and then transported to a drying zone at 70 ° C. for 10 seconds and dried to prepare a transparent support A subjected to alkali saponification treatment.

─────────────────────────────────────
Composition of alkaline solution ──────────────────────────────────────
Potassium hydroxide 2.0 parts by weight Water 6.5 parts by weight Isopropanol 85.0 parts by weight Surfactant SF-1: C ₁₄ H ₂₉ O (CH ₂ CH ₂ O) ₂₀ H 0.035 parts by weight Propylene glycol 6. 5 parts by mass─────────────────────────────────────

(Preparation of support A with alignment film before exposure)
An alignment film coating solution A having the following composition was continuously applied with a # 14 wire bar on the surface of the support A subjected to the alkali saponification treatment and subjected to the saponification treatment. The film was dried with warm air of 60 ° C. for 60 seconds and further with warm air of 100 ° C. for 120 seconds to form a support A with alignment film before exposure. The thickness of the alignment film before exposure was 0.45 μm.
────────────────────────────────────
Composition of coating liquid A for alignment film formation ────────────────────────────────────
Polymer material for alignment film (P-1) 2.4 parts by mass photoacid generator (S-1) 0.17 parts by mass radical polymerization initiator (Irgacure (registered trademark) 2959, manufactured by Ciba Specialty Chemicals)
0.18 parts by mass radical initiator (R-1) 0.18 parts by mass methanol 16.5 parts by mass IPA (isopropanol) 7.2 parts by mass water 73.55 parts by mass ────────── ─────────────────────────

(UV exposure)
Next, a stripe mask having a lateral stripe width of 12.7 mm at the transmission portion and a lateral stripe width of 12.7 mm at the shielding portion is placed on the above-prepared support A with alignment film before exposure, and is 200 nm in air at room temperature. Irradiation with ultraviolet light with a illuminance of 500 mW / cm ² in a wavelength region of ˜400 nm (Light Hammer 10, 240 W / cm, manufactured by Fusion UV Systems) as a light source unit is performed for 0.06 seconds (30 mJ / cm ² ). A pattern alignment film was formed.

(Formation of pattern retardation film 1)
The pattern alignment film after the above-mentioned ultraviolet exposure was rubbed once in one direction at 500 rpm while maintaining an angle of 45 ° with respect to the stripe of the stripe mask. Next, the following coating solution 1 for optically anisotropic layer was applied with a wire bar of # 3.2. Furthermore, after heating and aging at a film surface temperature of 110 ° C. for 2 minutes, it was cooled to 80 ° C. and irradiated with ultraviolet rays for 20 seconds using an air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) of 20 mW / cm ² under air. The pattern retardation film 1 was formed by fixing the alignment state. In the mask exposed portion, the discotic liquid crystal compound was vertically aligned with the slow axis direction parallel to the rubbing direction, and the unexposed portion was vertically aligned perpendicularly. The optical anisotropic layer 1 had a thickness of 1.15 μm and Re (550) of 130 nm.

────────────────────────────────────
Composition of optically anisotropic layer coating solution 1 ────────────────────────────────────
Discotic liquid crystal E-2 80 parts by mass Discotic liquid crystal E-3 20 parts by mass alignment film interface alignment agent (II-1) 0.9 parts by mass alignment film interface alignment agent (III-1) 0.08 parts by mass air interface Alignment agent (P-2) 0.2 parts by mass Air interface alignment agent (P-3) 0.6 parts by mass Photopolymerization initiator (Irgacure (registered trademark) 907, manufactured by BASF) 3.0 parts by mass Other functional monomer (Ethylene oxide modified trimethylolpropane triacrylate (Biscoat 360, manufactured by Osaka Organic Chemical Co., Ltd.)) 10 parts by mass Methyl ethyl ketone 268 parts by mass ─────────────────────── ─────────────
In the following E-2 and E-3, * represents a bonding position.

(Formation of pattern retardation film 2)
In the formation of the above-mentioned pattern retardation film 1, the following optical anisotropic coating liquid 2 in which various alignment agents were changed to 1.5 times the amount was prepared, and the same except that it was coated with a # 2.2 wire bar Pattern retardation film 2 was formed by the method. The film thickness of the optically anisotropic layer 2 was 0.77 μm, and Re (550) was 87 nm.

────────────────────────────────────
Composition of coating solution 2 for optically anisotropic layer ────────────────────────────────────
Discotic liquid crystal E-2 80 parts by mass Discotic liquid crystal E-3 20 parts by mass alignment film interface alignment agent (II-1) 1.4 parts by mass alignment film interface alignment agent (III-1) 0.12 parts by mass air interface Alignment agent (P-2) 0.3 parts by mass Air interface alignment agent (P-3) 0.9 parts by mass Photopolymerization initiator (Irgacure (registered trademark) 907, manufactured by BASF) 3.0 parts by mass Other functional monomer (Ethylene oxide modified trimethylolpropane triacrylate (Biscoat 360, manufactured by Osaka Organic Chemical Co., Ltd.)) 10 parts by mass Methyl ethyl ketone 268 parts by mass ─────────────────────── ─────────────

(Formation of pattern retardation films 3 to 6)
Pattern retardation films 3 to 6 having different film thicknesses and retardation values were formed by the same method as described above. The film thickness of the pattern retardation film 3 was 0.66 μm and Re (550) was 74 nm. The film thickness of the pattern retardation film 4 was 0.58 μm, and Re (550) was 65 nm. The film thickness of the pattern retardation film 5 was 0.33 μm, and Re (550) was 37 nm. The film thickness of the pattern retardation film 6 was 0.16 μm, and Re (550) was 19 nm.

In this example, dimming devices of Examples 1 to 3 and Comparative Example 1 shown below were manufactured using the above-described pattern retardation films 1 to 6. As a linear polarizer, a dye polarizing plate VHC-128 manufactured by Polatechno Co., Ltd. was used. As the reflective circular polarizer, a right circularly polarizing plate ChR and a left circularly polarizing plate ChL having a reflection band of 380 to 1250 nm were prepared by the method described in paragraph [0099] of International Publication No. 2015/33932. According to the following Table 9, the 1st polarizer and the 2nd polarizer were arrange | positioned, 2-4 pieces of pattern phase difference films | membranes and the pattern stripe were arrange | positioned in parallel among them.
For the light control devices of Examples 1 to 3 and Comparative Example 1, each retardation film was moved in the direction orthogonal to the stripes, and the gradation property was confirmed and the appearance of the stripe pattern between the gradations was evaluated as follows.
The appearance of the striped pattern between each gradation was evaluated as “excellent” when it was very difficult to see, “good” when it was difficult to see, and “bad” when it was visible.

  As shown in Table 9, in Examples 1 to 3, compared to Comparative Example 1, no stripe pattern was seen during driving.

DESCRIPTION OF SYMBOLS 10, 10a, 100 Light control apparatus 12 Light control part 14 Moving part 16 Control part 20 1st polarizer 22 1st polarizer 24 Phase difference part 30a-30d Pattern phase difference film 31 1st phase difference area 32, 34 Slow axis 33 Second phase difference region 40, 40a Movement mechanism

Claims (4)

A first polarizer, a second polarizer spaced apart from the first polarizer, and at least three sheets disposed between the first polarizer and the second polarizer. A pattern retardation film having a plurality of slow axis directions in the same plane, wherein the first polarizer, the second polarizer, and the pattern retardation films are arranged in parallel to each other. Hikari and
A moving unit that moves at least one of the three or more pattern retardation films relatively parallel to the other pattern retardation film;
Among the three or more pattern retardation films, at least two pattern retardation films have different retardation values,
From the first polarizer or the second polarizer, the moving unit moves at least one pattern retardation film relatively parallel among the three or more pattern retardation films. A light control device characterized by changing the transmittance of incident light.   Each of the pattern retardation films has two retardation regions whose slow axes are orthogonal to each other, and when viewed from the first polarizer side, all of the pattern retardation films have the slow axes. The light control device according to claim 1, wherein the light control device is arranged so as to be orthogonal or parallel to each other.   The light control device according to claim 1, wherein the pattern retardation film is formed of a composition containing a discotic liquid crystalline compound.   Each of the first polarizer and the second polarizer is a linear polarizer, or both are circular polarizers, and each pattern retardation film has a different retardation value at a wavelength of 550 nm. The dimming device according to claim 1, wherein a sum of retardation values of all the pattern retardation films is 220 nm to 320 nm.