JPH03167588A - Hologram and production thereof - Google Patents

Abstract

PURPOSE:To obtain a hologram having satisfactory transparency to visible radiation and high diffraction efficiency by using a compsn. consisting of a polymer contg. specified amts. of specified two kinds of structural units and a compd. selected among arom. aldehydes and arom. ketones. CONSTITUTION:A compsn. consisting of a polymer contg. 2-100mol% structural units represented by formula I and 0-98mol% structural units represented by formula II and a compd. selected among arom. aldehydes and arom. ketones which may have substituents is used. In the formulae I, II, each of X<1> and X<2> is H or alkyl, Y<1> is cycloalkenyl, etc., and Y<2> is phenyl, alkoxycarbonyl, etc. A hologram having satisfactory transparency to visible radiation and high diffraction efficiency can be obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a hologram and a method for manufacturing the same.

[Prior Art] A hologram is a recording of the interference wavefront of coherent light such as a laser beam as a refractive index distribution or a light absorption (a-light) distribution, and is used in stereoscopic photographs, beam scanners of bar code reading devices, etc. It is used in optical elements such as aircraft and head-up displays for automobiles, etc.

In order to use a hologram for the above purpose, it is necessary that the hologram has the following characteristics.

(1) High diffraction efficiency.

(2) Excellent moisture resistance, heat resistance, and light resistance.

(3) Be colorless and transparent.

(4) Less haze.

Known materials for holograms include bleached silver salts, photoresists, thermoplastics, dichromate gelatin, inorganic glass materials, and ferroelectric materials. Gelatin has been put into practical use.

[Problems to be Solved by the Invention] When producing a hologram using the bleached silver salt described above, there are drawbacks such as the need for complicated processing and the resulting hologram having poor light resistance. . Further, the hologram provided by dichromate gelatin has drawbacks such as poor moisture resistance and heat resistance.

One object of the present invention is to provide a hologram that has good transparency to visible light and high diffraction efficiency. Another object of the present invention is to provide a method for manufacturing the above-mentioned hologram.

[Means for Solving the Problems] According to the present invention, one of the above objects is achieved by solving the following general formula (I
) (hereinafter referred to as structural unit (1)) and the following general formula (I[)
Consisting of a polymer (A) having 0 to 98 mol% of the structural unit represented by (hereinafter referred to as structural unit (n)), and an aromatic aldehyde and an aromatic ketone that may have substituents. This is achieved by providing a hologram consisting of a composition consisting of a compound (B) selected from the group consisting of:

Structural unit (■): Y1 [In the formula, xl represents a hydrogen atom or an alkyl group, and Y1
represents a cycloalkenyl group or a group represented by the following general formula. Here, 21 represents a divalent hydrocarbon group, Rl,
Rt and R3 each represent a hydrogen atom, an alkyl group or an alkenyl group. Co-structural unit (■): ! snow [wherein x3 represents a hydrogen atom or an alkyl group, Y2 represents a phenyl group, an alkoxycarbonyl group or a carbamoyl group, and the hydrogen atom in general formula (II) may be substituted with a fluorine atom. ] The polymer (A) constituting the composition used in the present invention preferably contains 5 to 98 mol% of the structural unit (1), and 2
It is more preferable to contain 0 to 80 mol%.

X' in the above structural unit (1) and the structural unit (n
The alkyl group represented by X' in ) is preferably a lower alkyl group having 4 or less carbon atoms, such as a methyl group, ethyl group, probyl group, isopropyl group, or butyl group. In addition, the alkyl groups represented by RISRl and R3 in the structural unit (r) may have a branched chain or any substituent, such as methyl group, ethyl group, probyl group, isopropyl group, butyl group, amyl group, hexyl group, etc. A lower alkyl group having 8 or less carbon atoms, such as a hebutyl group or an octyl group, is preferable. The alkenyl groups represented by R', R' and R3 are preferably 2-butenyl, 3-methyl-2-butenyl, 3-pentenyl or 4-methyl-3-bentenyl. - The divalent hydrocarbon group represented by Z1 in the structural unit (1) is preferably an alkylene group having 2 to 8 carbon atoms which may have a branched chain. Structural unit (1
Preferable examples of Yl in ) include allyl group; 2-butenyl group, 3-butenyl group, 2-methyl-2-probenyl group; Methyl-2-butenyl group, 3-methyl-2-
Butenyl group, 2-ethyl-2-bropenyl group, 2-methyl-3-butenyl group, 1,2-dimethyl-2-bropenyl group; 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, x,t-nomethyl-2-
butenyl group, 1,2-dimethyl-2butenyl group, 1,3
-dimethyl-2-butenyl group, 2,3-dimethyl-2-
Butenyl group, 3-methyl-2-heptenyl group, 2-methyl-2-hebutenyl group; 2-methyl-2-cyclohexenyl group, 3-methyl-2-cyclohexenyl group, geranyl group, isogeranyl group, neryl group, lavanduril basis,
6-methylgeranyl group, l-methylgeranyl group,! 5 6-ethylgeranyl group, berylyl group, farnel group,
Examples include geranylgeranyl group and β-cyclogeranylgeranyl group. Y in structural unit (II)
Preferred examples of the alkoxycarbonyl group represented by ``a'' include a methoxycarbonyl group, an etquinocarbonyl group, a proboxycarbonyl group, a toquinocarbonyl group, a pentanoxycarbonyl group, a hexanoquinecarbonyl group, and a hebutanoxycarbonyl group. , cyclohexanoxycarbonyl group, etc.

The polymer (A) is obtained by homopolymerization of acrylic acid or its ester which may be substituted with an alkyl group at the α-position or copolymerization with a comonomer forming the structural unit (II), and then the polymer is obtained by copolymerization with a comonomer forming the structural unit (II). It can be produced by reacting the compound with an alcohol having a group Yl or by copolymerizing the acrylic acid derivative forming the structural unit (1) with the above comer.

As the acrylic acid derivative forming the structural unit (1),
Allyl methacrylate, allyl acrylate, 2 (or 3) 1-butenyl methacrylate, 2 (or 3) 1-butenyl acrylate, 2-methyl-2-propenyl methacrylate, 2-methyl-2-but σ benylacrylate, 2 (or 3 or 4) 1-heptenyl methacrylate, 2 (or 3 or 4) 1-heptenyl acrylate,
2-methyl-2 (or 3)-1 butenyl methacrylate, 2-methyl-2 (or 3)-1 butenyl acrylate, 2-ethyl-2-probenyl methacrylate, 2-ethyl-2-probenyl acrylate, 1 .2-dimethyl-2-propenyl methacrylate, 1,2-dimethyl-
2-probenyl acrylate, 2 (or 3 or 4 or 5)-hexenyl methacrylate, 2 (or 3 or 4 or 5)-hexenyl acrylate, 1.1 (
or 1.2 or 1.3 or 2,3) monodimethyl-
2-butenyl methacrylate, l,1 (or 1.2 or 1.3 or 2.3) monodimethyl-2-butenyl acrylate, 2 (or 3) monomethyl-2-hebutenyl methacrylate, 2 (or 3) Acrylic acid derivatives in which alcohol residues are chained, such as monomethyl-2-hebutenyl acrylate; 2 (or 3) monomethyl-2-
Acrylic acid derivatives with cyclic alcohol residues such as cyclohexenyl methacrylate, 2 (or 3) monomethyl-2-cyclohexenyl acrylate, geranyl methacrylate, geranyl acrylate, neryl methacrylate, neryl acrylate, isogeranyl methacrylate, isogeranyl Acrylate, lavanduryl methacrylate, lavanduryl acrylate, 6-methylgeranyl methacrylate, rylate, 6-ethylgeranyl methacrylate, 6-ethylgeranyl acrylate, berylyl methacrylate, berylyl acrylate, etc. Contains two non-conjugated double bonds Ester of chain or cyclic terbenesic alcohol and acrylic acid or methacrylic acid; non-conjugated double bond such as farnesyl methacrylate, farnesyl acrylate, geranylgeranyl methacrylate, geranylgeranyl acrylate, β-cyclogeranylgeranyl methacrylate, β-cyclogeranylgeranyl acrylate, etc. Examples include esters of chain or cyclic terbene-based alcohols having 1 or more terbenes and acrylic acid or methacrylic acid. Among these, allyl methacrylate, 2-methyl-2-propenyl methacrylate, 2-butenyl methacrylate, 2-methyl-2-
-Butenyl methacrylate, 2-hexenyl methacrylate, 3-hexenyl methacrylate, and geranyl methacrylate are preferred from the viewpoint of ease of obtaining alcohol as a raw material and ease of ester synthesis.

Comonomers forming the structural unit (II) include methacrylic acid; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, probyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, amyl methacrylate, and cyclohexyl methacrylate; Esters; Acrylic acid; Acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, probyl acrylate, butyl acrylate, bentyl acrylate, hexyl acrylate, amyl acrylate, cyclohexyl acrylate; Methacrylic acid amide Acrylic acid amide; Examples include substituted styrenes such as styrene and α-methylstyrene. The hydrogen atom in the structural unit ([) may be replaced by a fluorine atom.

Polymer (A) has a number average molecular weight of 7 in terms of boristyrene, determined by gel permeation xerography. l4
A value in the range of 1,000 to 1,000.000 is preferred. Polymer (A) has a number average molecular weight of 100,000
A range of 800.000 to 800.000 is more preferable.

Examples of the compound (B) include henzaldehyde, penzophenone, or derivatives thereof, which may have a substituent, and specifically, the following general formula (IV), general formula (V)
Or represented by general formula (W).

Yakiiri "x" X1 [In formula, x4, x5, X@, x7, x11, X@, X
IO Xll and Xl1 each represent a hydrogen atom, an alkyl group or alkoxy group having 7 or less carbon atoms, or a halogen atom;
, X'7OyohiX'6C each represents a hydrogen atom or a halogen atom, and n is 0,! Or 2. ] Preferred compounds (B) include penzophenone; 3 (or 4)-1 methylbenzophenone, 3 (or 4)-1 methoxybenzophenone, 3.3' (or 4,4°)
-dimethylbenzophenone, 3,3° (or 4.4°) -dimethoxybenzophenone, 2.3 (or 2.4
) ~ Chlorobenzophenone, 3.4.5- Substituted penzophenones such as }rimethoxybenzophenone: 3-penzoylbenzophenone; 3 (or 4) monomethylbenzoyl-3゛ (or 4゜) monomethylbenzo Phenon; 3
(or 4) Meta-substituted henzophenone such as monomethoxybenzoyl-3' (or 4°) monomethoxybenzophenone, 3.3'-sibenzoylbenzophenone, 1,3.5-tribenzoylbenzene, benzaldehyde ; Substituted benzaldehydes such as 3 (or 4)-monomethylbenzaldehyde, 3 (or 4)-monomethoxybenzaldehyde, 3,4-dimethylbenzaldehyde, and 3,4-dimethoxybenzaldehyde can be mentioned. Among these, benzaldehyde, penzophenone,
3-penzoylbenzophenone, 33'-dibenzoylbenzophenone and 1,3.5-tribenzoylbenzene are preferred from the viewpoint of ease of synthesis, and 3-penzoylbenzophenone and 1,3.5-tribenzoyl Benzene is particularly preferred because it has good photoreactivity, can increase the difference in refractive index between exposed and non-exposed areas, and provides high solvent resistance and heat resistance of the produced hologram.

The composition ratio of polymer (A) and compound (B) is 1:1 to
The range of l:lO (weight ratio) is preferably 3:1 to 1.2.
(weight ratio) is more preferable. The ratio of the structural unit (1) of the polymer (A) to the compound (B) is 10:1 to
The range is 1:20 (molar ratio), preferably 5:1-
The range is 1:10 (molar ratio).

According to the present invention, another object of the above is to provide a method for manufacturing a hologram made of the above-mentioned composite material, which is characterized by providing the following steps (a), (0 and (c)). This is achieved by providing

(a) A step of forming a thin film of the above composition.

0) A step of partially irradiating the thin film with ultraviolet rays according to a desired pattern.

(c) Remove unreacted compound (B) from the thin film. The process of doing.

In the above step (a), the polymer (A) and the compound (B) are dissolved in a solvent that dissolves them, and the resulting solution is used to form a thin film by a casting method, bar coating method, spin coating method, etc. To run away. The method for forming the 6WI film, in which the solvent is removed from the thin film by subjecting the thin film to vacuum treatment or heat treatment, as required, is selected depending on the desired thickness or form of the 74 film. Thin film thickness is 0.5-50μ
m range, the Subin coat method is adopted.

Following the (A) process (in the 0 process, the thin film is partially irradiated with ultraviolet light with a wavelength of 200 to 450 rv according to the hologram pattern. The light source is a high-pressure mercury lamp, N, gas laser, He-Cd laser, Ar A laser or the like is used.As a method for forming a hologram pattern, a mask exposure method using a photomask, an interference exposure method, a laser beam direct writing method, etc. are employed.

Unreacted compounds (
Removal of B) is usually carried out by heat treatment under reduced pressure or normal pressure. The temperature of the heat treatment is preferably in the range of 50 to 100°C. As a result, a hologram is obtained in which the exposed portion has a higher refractive index than the unexposed portion and is thicker.

In the hologram manufacturing method of the present invention, a step (2) of irradiating the entire surface of the thin film with a hologram pattern with ultraviolet rays may be provided after the step (c). By passing through this (2) step, the organic solvent resistance and heat resistance of the manufactured hologram are further improved. The ultraviolet rays to be irradiated preferably have an intensity of 10 to 40 mW/cm" and a wavelength of 200 to 450 nm. The duration of ultraviolet irradiation is preferably in the range of 30 seconds to 5 minutes. After (2) or if necessary, a (4) step may be provided in which heat treatment is performed at a higher temperature than the heat treatment temperature in (3). The organic solvent resistance and heat resistance of the hologram are further improved.
Temperatures in the range 05-230°C for 15 minutes to 40 hours give suitable results. More preferable results are obtained by heat treating at a temperature in the range of 150 to 200°C for 5 hours or at a temperature in the range of 110 to 140°C for 10 to 25 hours.

After the step (a), a step (f) may be provided in which the entire surface of the thin film made of the above composition is irradiated with ultraviolet rays under conditions in which only a portion of the compound (B) reacts.

Note that a hologram having a desired refractive index difference and unevenness difference can also be obtained by partially irradiating a thin film made of the above composition with ultraviolet rays according to the pattern of the hologram, and then immersing it in a jig. .

The hologram of the present invention has a pitch in the range of 0.2 to 5μ, and a refractive index difference of 0.2 to 5 μm between exposed and non-exposed areas.
The range of 0.001 to 0.1 is preferred.

The hologram of the present invention has high diffraction efficiency, small variation, good transparency, and little haze. Therefore, the hologram of the present invention is preferably used in head-up displays for automobiles.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Example! N in the reaction vessel, 2-butenyl methacrylate 2 after substitution
6g1 Methyl methacrylate 56g1 90mg of azobisisobutyronitrile and 300g of dioxane were charged, sealed, and heated in a water bath at 55 to 60°C for 24 hours.
A polymerization reaction was carried out by heating for a period of time. The obtained reaction limb was poured into methanol Iff to precipitate the product, and the product was dried to obtain 50 g of polymer (A). This polymer (^
) was confirmed by NMR measurement to be a copolymer with a molar ratio of 2-butenyl methacrylate to methyl methacrylate of 1:3.

The molecular weight of this polymer (^) was determined by gel permeation chromatography, and the number average molecular weight in terms of polystyrene was 220,000.

After dissolving a composition consisting of 10 parts of polymer (A) and 8 parts of 3-penzoylbenzophenone in toluene, a thin film (thickness 12 μg+) was formed on a glass substrate using the Svin coating method using the obtained solution. Formed.

This thin film was exposed to a hologram grid pattern using an interference exposure apparatus shown in FIG. In the interference exposure apparatus, an Ar laser 1 having a wavelength of 363.8 nm is emitted, and light incident on an interference optical system 2 is reflected by a mirror 3 and then split into two by a beam splitter 4. The two-split light is reflected by the mirror 5 (6) and then passes through the lens system 7 (8).
) to form a parallel tip and form an interference pattern on the exposure surface 9.

In this example, the period of the obtained hologram is 0.43
Interference exposure was performed by adjusting the lens system and mirror so that the distance was .mu.m.

After interference exposure, the patterned WI film was heat treated in a vacuum dryer at 98° C. and 0.2 nmHg for 17 hours to remove unreacted compound (B) from the thin film. Thereafter, a hologram was obtained by irradiating the entire surface of the thin film with 20 ml/cm'' ultraviolet light for 6 minutes.

The diffraction efficiency of the obtained hologram for light having a wavelength of 632.8 nm was 40% for light polarized in the same direction as the lattice pattern of the hologram, and 16% for light polarized in the perpendicular direction. Next, FIG. 2 shows a spectral transmission characteristic diagram of this hologram for visible light. here,
FIG. 2 shows the results obtained by arranging the hologram so that the diffraction efficiency for light with a wavelength of 632.8 na+ is maximized and measuring it. As is clear from FIG. 2, the above hologram has a transmittance of 90% or more for light of wavelengths other than the wavelength at which diffracted light is generated, and has extremely good transparency for visible light.

Examples 2 to 19 Compositions consisting of the polymer (A) shown in Table 1 and the compound (B) were prepared in the same manner as in Example 1.

Holograms were prepared as in Example 1 using the compositions shown in Table 1.

The holograms produced in each example had high diffraction efficiency and good transparency, similar to the hologram of Example I.

Below is the margin Example 20 N in the reaction vessel, 4 g of geranyl methacrylate after substitution,
5 g of methyl methacrylate, 8 III g of azobisisobutyronitrile and 25 g of dioxane were charged, the tube was sealed and heated in a water bath at 55 to 60° C. for 24 hours to carry out a polymerization reaction. The resulting reaction solution was diluted with methanol 4500 ml.
45 g of polymer (A) was obtained by precipitating the product and drying it. This polymer (A) was found to have a molar ratio of geranyl methacrylate to methyl methacrylate of 1 as determined by NMR measurement. The number average molecular weight of this polymer (A) in terms of polystyrene was 250,000, as determined by gel permeation chromatography.

A composition consisting of 10 parts of the above polymer (A) and 10 parts of 3-henzoylhenzophenone was dissolved in toluene, and a thin film (thickness 12 μm ) was formed and interference exposure was performed under the same conditions as in Example 1. After interference exposure, it was dried in a vacuum dryer at 98°C and 0.5°C. A hologram was produced by heat-treating at 2 mmHg for 17 hours and removing unreacted compound (B).

This hologram had high diffraction efficiency like the hologram of Example 1, and good transparency.

Examples 21 to 34 In the same manner as in Example 20, composites consisting of the polymer (A) shown in Table 2 and the compound (B) were prepared. A hologram was manufactured in the same manner as in Example 1 using the composite shown in Table 2.

The holograms produced in each example had high diffraction efficiency and good transparency, similar to the hologram of Example I.

In addition, in Tables 1 and 2, parts indicate parts by weight.

Margin below [Effects of the Invention] According to the present invention, a hologram having good transparency to visible light and high diffraction efficiency is provided. In this hologram, the exposed portion has a higher refractive index than the non-exposed portion and is thicker. Further, according to the present invention, a method of manufacturing the above-mentioned hologram is provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an interference exposure apparatus used for manufacturing the hologram of the present invention, and FIG. 2 is a diagram of the spectral transmission characteristics of the hologram of Example 1 for visible light. 1... Ar laser, 4... Beam splitter, 7.8... Lens system, 9... Exposure surface.

Claims (1)

[Claims] 1. The following general formula (I) (I)▲ Numerical formulas, chemical formulas, tables, etc.▼ [In the formula, X^1 represents a hydrogen atom or an alkyl group, and Y
^1 represents a cycloalkenyl group or a group represented by the following general formula ▲ Numerical formulas, chemical formulas, tables, etc. are available▼. Here, Z^1 represents a divalent hydrocarbon group, and R^1, R^2 and R^3 each represent a hydrogen atom, an alkyl group or an alkenyl group. ] 2 to 100 mol% of the structural unit represented by the following general formula (
II) (II)▲Mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, X^2 represents a hydrogen atom or an alkyl group, and Y
^2 represents a phenyl group, an alkoxycarbonyl group or a carbamoyl group, and the hydrogen atom in general formula (II) may be substituted with a fluorine atom. ] A polymer having 0 to 98 mol% of structural units represented by (A
) and a compound (B) selected from the group consisting of aromatic aldehydes and aromatic ketones that may have substituents. 2. (a) The following general formula (I) (I) ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ [In the formula, X^1 represents a hydrogen atom or an alkyl group, and Y
^1 represents a cycloalkenyl group or a group represented by the following general formula ▲ Numerical formulas, chemical formulas, tables, etc. are available▼. Here, Z^1 represents a divalent hydrocarbon group, and R^1, R^2 and R^3 each represent a hydrogen atom, an alkyl group or an alkenyl group. ] 2 to 100 mol% of the structural unit represented by the following general formula (
II) (II)▲Mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, X^2 represents a hydrogen atom or an alkyl group, and Y
^2 represents a phenyl group, an alkoxycarbonyl group or a carbamoyl group, and the hydrogen atom in general formula (II) may be substituted with a fluorine atom. ] A polymer having 0 to 98 mol% of structural units represented by (A
) and a compound (B) selected from the group consisting of aromatic aldehydes and aromatic ketones which may have substituents; (b) forming a desired pattern on the thin film; A method for manufacturing a hologram, comprising the following steps: partially irradiating ultraviolet rays according to the conditions; and (c) removing unreacted compound (B) from the thin film.