JP2003195025A - Method for manufacturing multicolor optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a multicolor optical element with which the practical multicolor optical element comprising various kinds of optically functional layers laminated on a cholesteric layer is easily manufactured. <P>SOLUTION: A cholesteric liquid crystal coating film 13' is formed by applying a radiation curing chiral nematic liquid crystal containing a monomer with chirality and with an optically active group as a component on an alignment layer 12 with imparted alignment controllability (figure 1 (a)). Next, the liquid crystal is oriented by heating the cholesteric liquid crystal coating film 13' ((b)) which is subsequently irradiated with active light rays which activate the optically active group via a photomask 20 with transmittance varying from region to region to be irradiated so as to form a cholesteric layer 13 with desired display regions and display colors ((c)). Thereafter, the liquid crystal is oriented by heating the cholesteric layer 13 ((d)) and subsequently the cholesteric layer 13 is three-dimensionally cross-linked and hardened by being irradiated with ultraviolet rays with wavelengths inactive to the optically active group ((e)). Finally the surface of the cholesteric layer 13 is subjected to surface modification treatment ((f)) and subsequently a protective layer 14 is film formed on the surface with a wet process ((g)). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a multicolor optical element used for color display in a liquid crystal display element or the like, and more particularly to the production of a multicolor optical element made of liquid crystal having cholesteric regularity. Regarding the method.

[0002]

2. Description of the Related Art Conventionally, as a multicolor optical element made of liquid crystal having cholesteric regularity, a multicolor display plate, a color filter, a polarizing element, etc. have been known. As a method of forming a desired multicolor pattern in such a multicolor optical element, for example, as described in JP-A No. 11-153798, an arbitrary display color having an arbitrary display area (for example, red A method is known in which colored layers of (R), green (G), and blue (B) are formed one by one by photolithography. Also, JP-A-59-8
As described in Japanese Patent No. 3113, there is also known a method of adjusting a display color for each arbitrary display area by controlling temperature.

However, the above-mentioned Japanese Patent Laid-Open No. 11-1537.
The method described in Japanese Patent Laid-Open No. 98 requires a photolithography step for the same number of times as the number of display colors required, and thus has a problem of high production cost. Further, in the method described in JP-A-59-83113, since the display color is adjusted by controlling the temperature, the manufacturing process becomes complicated, and the boundary (color section) between the display areas is complicated. However, there is a problem that it is difficult to reduce the size of the display area due to the vagueness.

By the way, International Patent Application Publication WO00 / 3
In Japanese Patent No. 4808, a liquid crystal having a cholesteric regularity containing a monomer having a chirality and an optically active group as a component is irradiated with an active ray, and the optically active group of the liquid crystal is deactivated by the irradiation of the active ray. A method of forming a cholesteric layer (a layer having cholesteric regularity) having a desired multicolor pattern is proposed. Specifically, in this method, a cholesteric layer having a desired display area and display color is formed according to the irradiation area and irradiation amount of actinic rays, and then,
The display area and display color of the cholesteric layer are fixed by irradiating with ultraviolet light having a wavelength at which the optically active group does not show activity. According to this method, a cholesteric layer having a desired display pattern can be formed by a single photolithography process by controlling the irradiation amount of active rays for each display area using photomasks having different transmittances. You can Therefore, the manufacturing process is simplified,
It is also easy to miniaturize the display area.

[0005]

However, in the method described in International Patent Application Publication No. WO00 / 34808, the step of forming a cholesteric layer having a desired display area and display color, and the display area of the cholesteric layer. And since it is necessary to irradiate a large amount of actinic rays such as ultraviolet rays in the step of fixing the display color,
Finally, the wettability of the surface of the cholesteric layer cured by three-dimensional crosslinking becomes low. Here, when the cholesteric layer produced in this manner is used as a multicolor optical element in a liquid crystal display element or the like, various optical functional layers (for example, a flattening layer) may be formed on the surface of the cholesteric layer according to the usage pattern. Layers, protective layers, diffusion layers, alignment layers, electrodes and other cholesteric layers, etc.) are often formed into a laminated structure, but when the surface wettability of the cholesteric layer is low,
There is a problem that it becomes difficult to form an optical functional layer by using a wet process generally used in actual manufacturing, and a practical multicolor optical element cannot be easily manufactured.

The present invention has been made in consideration of the above points, and it is possible to easily manufacture a practical multicolor optical element in which various optical functional layers are laminated on a cholesteric layer. It is an object to provide a method for manufacturing an optical element.

[0007]

The present invention irradiates a radiation-curable liquid crystal having cholesteric regularity containing a monomer having chirality as a component with an actinic ray, and adjusts the irradiation area and the irradiation amount of the actinic ray. A step of forming a cholesteric layer having a desired display area and a display color, a step of irradiating the cholesteric layer irradiated with actinic rays with radiation to three-dimensionally cure the cholesteric layer, and a three-dimensional crosslinking And a step of performing a surface modification treatment on the surface of the cholesteric layer cured, and a step of forming a desired optical functional layer on the surface of the cholesteric layer subjected to the surface modification treatment by a wet process There is provided a method for manufacturing a polychromatic optical element, which comprises:

In the present invention, the surface of the cholesteric layer is modified so that the surface of the cholesteric layer has a contact angle of 0 ° to 70 ° with respect to pure water at 25 ° C. It is preferable to perform quality treatment.
Further, the optical functional layer is preferably selected from the group consisting of a flattening layer, a protective layer and a diffusion layer. The optical functional layer may be another cholesteric layer having the same characteristics as the cholesteric layer or an absorption color filter.

According to the present invention, a desired display area and display color are formed by irradiation with actinic rays, and the surface of the cholesteric layer cured by three-dimensional crosslinking by irradiation with ultraviolet rays is subjected to a surface modification treatment. After applying, since the desired optical functional layer is formed on the surface of the cholesteric layer, in the multicolor optical element in which the wettability of the surface of the cholesteric layer is likely to be lowered by irradiation with actinic rays and radiation. In addition, it is possible to easily form a desired optical functional layer on the surface of the cholesteric layer by a wet process, which facilitates the practical multicolor optical element in which various optical functional layers are laminated on the cholesteric layer. Can be manufactured.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining an embodiment of a method for manufacturing a multicolor optical element according to the present invention. In this embodiment, a case of manufacturing a multicolor display plate having display regions of three colors of red (R), green (G) and blue (B) will be described as an example.

First, as shown in FIG. 1 (a), an alignment film 12 is formed on a glass substrate 11, and a rubbing treatment is applied to the surface of the alignment film 12 to give an alignment ability. Then, a radiation-curable low-molecular weight chiral nematic liquid crystal having cholesteric regularity containing a monomer having chirality and an optically active group as a component is provided on the orientation film 12 having the orientation ability. Apply to form a cholesteric liquid crystal coating 13 '.

Next, as shown in FIG. 1 (b), the cholesteric liquid crystal coating film 13 'is heated at a temperature above the liquid crystal transition temperature of the chiral nematic liquid crystal (for example, 80 ° C.) for a predetermined time (for example, 30 seconds). The chiral nematic liquid crystal is aligned by the alignment control force of the surface of the alignment film 12.

After that, as shown in FIG. 1C, through a photomask 20 having a different transmittance for each irradiation area,
Actinic rays that activate the optically active groups for the cholesteric liquid crystal coating 13 '(for example, ultraviolet rays in the atmosphere)
To deactivate the optically active group of the chiral nematic liquid crystal, thereby forming the cholesteric layer 13 having a desired display area and display color according to the irradiation area and the irradiation amount of the active light. In the photomask 20, the region 21a has a transmittance of 100%, and the region 21b has a transmittance of 50%.
%, The region 21c has 0% transmittance.

Then, as shown in FIG. 1D, the cholesteric layer 13 irradiated with the actinic ray is kept at a temperature lower than the liquid crystal transition temperature of the chiral nematic liquid crystal (for example, 50 ° C.) for a predetermined time (for example, It is heated for 60 seconds), and the chiral
Align nematic liquid crystals. In addition, here, since the heating alignment treatment is performed at a temperature lower than the liquid crystal transition temperature of the chiral nematic liquid crystal, the thermal diffusion of liquid crystal molecules at the interface between different display regions is effectively suppressed, The planar orientation of the cholesteric layer 13 can be effectively aligned.

After that, as shown in FIG. 1 (e), a predetermined amount (for example, 1.5 J / cm) of ultraviolet light having a wavelength at which the optically active group does not show activity is given to the cholesteric layer 13 subjected to the heat orientation treatment. ² ) Only irradiate, cholesteric layer 13
The cholesteric layer 13 is hardened by three-dimensionally crosslinking and polymerizing. At this time, the chiral
As a method of curing the nematic liquid crystal, a method of irradiating the liquid crystal with ultraviolet rays or a method of irradiating the liquid crystal with an electron beam can be used. Here, "three-dimensional bridge"
Means that the liquid crystal molecules are three-dimensionally polymerized with each other to form a network structure. By making such a state, it is possible to optically fix the state of the liquid crystal, and easy to handle as an optical film,
A stable film-like film can be obtained at room temperature. As shown in FIG. 1 (e), the finally obtained cholesteric layer 13 has three color display regions (red display region (R), green display region (G) and blue display region (B)). have.

Next, as shown in FIG. 1 (f), the surface of the cholesteric layer 13 cured by three-dimensional crosslinking is subjected to a surface modification treatment. Here, as the surface modification treatment, any method can be used as long as it does not impair the orientation ability of the surface of the cholesteric 13, and U using ultraviolet rays is used.
V ozone treatment, plasma treatment using various gases,
Electron beam radiation treatment, treatment with a surface modifier, etc. can be used. The surface of the cholesteric layer 13 that has been subjected to such surface modification treatment preferably has a contact angle of 0 ° or more and 70 ° or less with respect to pure water at 25 ° C.

Finally, as shown in FIG. 1G, a protective layer (optical functional layer) 14 is formed on the surface of the surface-modified cholesteric layer 13 by a wet process. Here, the “wet process” means a step of forming a coating film by applying the film formation target on the surface of the cholesteric layer 13 in a liquid phase state. In addition to the protective layer 14, a desired optical functional layer can be formed on the surface of the cholesteric layer 13, for example, a flattening layer, a protective layer, a diffusion layer, etc. can be formed. Further, another cholesteric layer having the same characteristics as the cholesteric layer 13 may be formed, or an absorption type color filter such as a pigment dispersion type color filter may be formed.

As described above, according to the present embodiment, a desired display region and display color are formed by irradiation with actinic rays, and the surface of the cholesteric layer 13 that is three-dimensionally crosslinked and cured by irradiation with ultraviolet rays is applied to the surface. Then, after the surface modification treatment, the protective layer 14 is formed on the surface of the cholesteric layer 13.
Since it is designed to form a desired optical functional layer such as
Even in the multicolor optical element 10 in which the wettability of the surface of the cholesteric layer 13 is likely to be deteriorated by irradiation with actinic rays and radiation, the protective layer 14 is formed on the surface of the cholesteric layer 13.
It is possible to easily form a desired optical functional layer such as a film by a wet process. Therefore, the cholesteric layer 13
A practical multicolor optical element 10 having various optical functional layers laminated thereon can be easily manufactured.

[0019]

EXAMPLES Next, specific examples of the above-described embodiment will be described.

Example 1 85% by weight of a monomer represented by the following chemical formula (1) and having a liquid crystal transition temperature of 80 ° C.
And a 40 wt% toluene solution in which 14 wt% of a monomer having a chirality and an optically active group represented by the following chemical formula (2) and 1 wt% of a photoinitiator (Darocure4265) were dissolved were prepared. .

[0021]

[Chemical 1]

[Chemical 2] On the other hand, a polyimide film (alignment film) having a film thickness of 0.1 μm was formed on a glass substrate, and the surface of the polyimide film was subjected to rubbing treatment in a certain direction to impart alignment ability.

Next, such a glass substrate with a polyimide film is set on a spin coater, and the toluene solution is deposited on the polyimide film under predetermined conditions (rotation speed 1000 rpm, rotation time 15 seconds). Was applied by a spin coating method to form a cholesteric liquid crystal coating film. Then, the cholesteric liquid crystal coating film was heated at 80 ° C. for 30 seconds to evaporate the toluene in the toluene solution and align the liquid crystal. As a result, the central wavelength of the selected wavelength band is 460n
A blue reflector of m. was obtained.

Thereafter, the transmittance is 100%, 50%, 0%.
Through a photomask formed by arranging the three regions in a stripe pattern at a pitch of 100 μm, the cholesteric liquid crystal coating film is exposed to 0.4 nm UV light having a wavelength of 365 nm in the air atmosphere.
After irradiating only J / cm ² , the liquid crystal was aligned by heating at 50 ° C. for 60 seconds.

Then, an ultraviolet ray having a wavelength of 405 nm was irradiated at 2.0 J / cm ^{2 in} a nitrogen atmosphere to cure the cholesteric liquid crystal coating film (cholesteric layer). As a result, a stripe-shaped display region having a line width of 100 μm (center wavelength of the selected wavelength band is 650 nm (red), 550 nm
A multicolor reflector having (green) and 460 nm (blue) was made. In this example, seven such multicolor display plates were manufactured.

Next, different treatments were applied to the surfaces of the seven multicolor reflectors produced in this way, using a UV irradiation device (low pressure mercury lamp, 110 W × 5 lamps) manufactured by Oak Manufacturing Co., Ltd. Time (60 seconds, 120 seconds, 140 seconds, 1
UV ozone treatment was performed for 60 seconds, 180 seconds, 300 seconds, and 600 seconds) to prepare seven types of samples. As a comparative example, a sample having a treatment time of 0 seconds, that is, no UV ozone treatment was prepared.

Then, a flattening overcoat material AC-81 is formed on the surface of each of the eight kinds of samples.
00 (manufactured by Nissan Chemical Industries, Ltd.) was applied by a spin coating method to form a protective layer.

(Evaluation Results) For seven kinds of samples as Examples 1 to 7 and a sample as a comparative example,
Before forming the protective layer, the contact angle to pure water at 25 ° C. was measured using a contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd. Further, after forming the protective layer, the degree of film formation of the protective layer was visually observed. The results are shown in Table 1.

As shown in Table 1, in the samples of Examples 1 to 7 which were subjected to the surface modification treatment, the protective layer in a better condition was formed as compared with the sample of the comparative example. Also, there is a clear relationship between the contact angle and the degree of film formation of the protective layer,
For the samples with a contact angle of 70 degrees or less, a very uniform in-plane protective layer was formed. On the other hand, the contact angle is 7
With respect to the samples exceeding 0 degree, after the spin coating of the protective layer, the phenomenon of "repelling" was observed in a part of the surface, and the state of the formed protective layer was insufficient.

[0029]

[Table 1]

[0030]

As described above, according to the present invention, a practical multicolor optical element in which various optical functional layers are laminated on a cholesteric layer can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a process drawing for explaining an embodiment of a method for manufacturing a multicolor optical element according to the present invention.

[Explanation of symbols]

10 Multicolor optical element 11 glass substrate 12 Alignment film 13 'cholesteric liquid crystal coating 13 Cholesteric layer 14 Protective layer

Claims (5)

[Claims] 1. A radiation-curable liquid crystal having cholesteric regularity, which contains a monomer having chirality as a component, is irradiated with an actinic ray, and a desired display area and display color corresponding to the irradiation area and the irradiation amount of the active ray. A step of forming a cholesteric layer having: a step of irradiating the cholesteric layer irradiated with an actinic ray with radiation to three-dimensionally crosslink and cure the cholesteric layer, and the cholesteric layer cured by three-dimensional crosslinking And a step of forming a desired optical functional layer on the surface of the cholesteric layer subjected to the surface modification treatment by a wet process. , Method for manufacturing multicolor optical element. 2. A surface modification treatment is applied to the surface of the cholesteric layer so that the contact angle of the surface of the cholesteric layer with pure water at 25 ° C. is in the range of 0 ° to 70 °. The method for manufacturing a multicolor optical element according to claim 1, characterized in that. 3. The production of a multicolor optical element according to claim 1, wherein the optical functional layer is selected from the group consisting of a flattening layer, a protective layer and a diffusion layer. Method. 4. The method for manufacturing a multicolor optical element according to claim 1, wherein the optical functional layer is another cholesteric layer having the same characteristics as the cholesteric layer. 5. The method for manufacturing a multicolor optical element according to claim 1, wherein the optical functional layer is an absorption type color filter.