JP7115531B2 - reflectors and optics - Google Patents

Description

The present invention relates to reflectors and optical components.

In recent years, translucent cover members made of resin are used as cover films for display devices such as liquid crystal displays, lenses for eyewear such as sunglasses and spectacles, and window members for transportation means such as motorcycles and cars. Further, it is known to apply a mirror film that selectively reflects light in the visible light region as light having a specific wavelength region to the translucent cover member.

In recent years, this mirror film is composed of a laminate in which a high refractive index layer with a high refractive index and a low refractive index layer with a low refractive index are alternately laminated with respect to light having a specific wavelength region. A multi-layer laminated film, that is, a multi-layer laminated reflector plate has been proposed that selectively reflects light having a specific wavelength region by providing a repeating portion with a specific wavelength range (see, for example, Patent Document 1).

In addition, when this mirror film is applied to, for example, display devices and solar panels for vehicles, and eyewear for sports, it is expected to be used under severe conditions, so it is excellent. It is required to have heat resistance.

However, when the mirror film is used under such severe conditions, the function as a multilayer laminated reflector is degraded due to a change in the film thickness of the refractive index layer having a lower glass transition point. I had a problem to say.

JP 2020-86456 A

An object of the present invention is to provide a reflector that selectively reflects light in the visible light region, comprising a repeating portion composed of a laminate in which high refractive index layers and low refractive index layers are alternately laminated, To provide a reflector capable of exhibiting excellent heat resistance even when used under severe conditions, and to provide an optical component having such a reflector and having excellent reliability.

Such objects are achieved by the present invention described in (1) to ( 8 ) below.
(1) A reflector comprising a laminate in which high refractive index layers and low refractive index layers are alternately and repeatedly laminated,
The refractive index of the high refractive index layer is higher than the refractive index of the low refractive index layer,
where Tg1 is the glass transition point of the main material forming the high refractive index layer and Tg2 is the glass transition point of the main material forming the low refractive index layer, Tg1 and Tg2≧105° C.;
The refractive index difference (N1−N2) is 0.05 or more and 0.05 or more, where N1 is the refractive index of the high refractive index layer at a wavelength of 589 nm and N2 is the refractive index of the low refractive index layer at a wavelength of 589 nm. is 25 or less ,
When the laminated body is formed into a curved laminated body having a curved shape with a curvature radius of 60 mm at a temperature 10° C. higher than the higher glass transition point of the glass transition point Tg1 and the glass transition point Tg2 R1 [%] is the reflectance of light with a wavelength of 589 nm of the curved laminate,
After the curved laminate is stored in a thermal circulation oven in a temperature environment of 105° C. for 1000 hours, R2/R1× A reflector having a reflectance retention of 80% or more, which is required at 100[%] .

( 2 ) The reflector according to ( 1 ), wherein the curved laminate has a reflectance R1 of 40% or more for light with a wavelength of 589 nm.

( 3 ) The laminate according to (1) or (2) above, wherein the number of repetitions in which the high refractive index layers and the low refractive index layers are alternately laminated is 50 times or more and 750 times or less. reflector.

( 4 ) The reflector according to any one of (1) to ( 3 ), wherein the glass transition point Tg1 and the glass transition point Tg2 satisfy the relationship 0°C≤|Tg1-Tg2|≤60°C.

( 5 ) The reflector according to any one of (1) to ( 4 ) above, wherein the lower one of the glass transition point Tg1 and the glass transition point Tg2 is 110° C. or higher and 250° C. or lower.

( 6 ) The reflector according to any one of (1) to ( 5 ) above, wherein the high refractive index layer has a refractive index N1 of 1.57 or more and 1.85 or less at a wavelength of 589 nm.

( 7 ) The reflector according to any one of (1) to ( 6 ) above, wherein the low refractive index layer has a refractive index N2 of 1.49 or more and 1.67 or less at a wavelength of 589 nm.

( 8 ) An optical component comprising the reflector according to any one of (1) to ( 7 ) above.

According to the present invention, a reflector that selectively reflects light in the visible light region and that includes a repeating portion composed of a laminate in which high refractive index layers and low refractive index layers are alternately laminated, Accurately suppressing or preventing a change in thickness of a refractive index layer having a lower glass transition point out of a low refractive index layer and a high refractive index layer included in a reflector plate even when used under severe conditions. be able to. Therefore, this reflector exhibits excellent heat resistance.

1 is a longitudinal sectional view showing an embodiment of a mirror film to which a reflector of the invention is applied; FIG. FIG. 2 is an enlarged cross-sectional view of a portion of a reflector included in the mirror film located in the region [B] surrounded by the dashed line in FIG. 1;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the reflector of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
In addition, below, the mirror film to which the reflector of this invention was applied is demonstrated as an example.

<Mirror film>
FIG. 1 is a vertical cross-sectional view showing an embodiment of a mirror film to which the reflector of the present invention is applied, and FIG. 2 is a mirror film located in the area [B] surrounded by the dashed line in FIG. FIG. 4 is an enlarged cross-sectional view enlarging a part of the reflector; For convenience of explanation, the upper side in FIGS. 1 and 2 is hereinafter referred to as "upper" or "upper", and the lower side is referred to as "lower" or "lower". In addition, in FIGS. 1 and 2, the mirror film is shown in a flat state, and the thickness direction is exaggerated and schematically shown for easy understanding.

In this embodiment, the mirror film 1 comprises, as shown in FIG. 1, a reflective layer 3 that selectively reflects light having a specific wavelength range, and upper and lower surfaces (one surface and the other surface) of the reflective layer 3. It is composed of a laminated plate provided with a hard coat layer 5 laminated on both sides.

In the mirror film 1, the reflecting layer 3 included in the mirror film 1 is composed of the reflecting plate of the present invention. Hereinafter, each layer constituting the mirror film 1 will be described.

The reflective layer 3 is an intermediate layer located in the center of the mirror film 1 in the thickness direction. and selectively transmits light that is not reflected by this reflection. This reflective layer 3 is composed of the reflective plate of the present invention.

As shown in FIG. 2, the reflective layer 3 is a laminate in which a high refractive index layer 31 having a high refractive index and a low refractive index layer 32 having a low refractive index are alternately laminated with respect to light in the visible light region. It is a multi-layer laminated film (multi-layer laminated reflector) provided with a repeating portion 33 composed of a body. That is, the reflective layer 3 has a structure in which one high-refractive-index layer 31 is sandwiched between two low-refractive-index layers 32 by repeating the repeating portion 33 a plurality of times. is.

In the reflective layer 3, the high refractive index layer 31 contains a resin material having a high refractive index for light in the visible light region, and the low refractive index layer 32 contains a low refractive index for light in the visible light region. By using a structure containing a resin material, between the high refractive index layer 31 and the low refractive index layer 32, the refractive index difference for light in the visible light region is increased, and the refractive index difference for non-reflected light is decreased. can be done. As a result, the reflective layer 3 can function as a multilayer laminated film that selectively reflects light in the visible light region and transmits light that is not reflected as transmitted light, ie, a multilayer laminated reflector. In other words, the reflective layer 3 is such that when light in the visible region is incident on the reflective layer 3 as incident light, the transmitted light is maximally blocked (reflected), i.e., transmitted at a minimum, whereas the reflected light is When light that is not reflected enters the reflecting layer 3 as incident light, it functions as a multi-layer laminated reflector that blocks the transmitted light with a minimum amount, that is, transmits the maximum amount of light.

Here, in the present invention, specifically, in the reflective layer 3, when the refractive index of the high refractive index layer 31 at a wavelength of 589 nm is N1 and the refractive index of the low refractive index layer 32 at a wavelength of 589 nm is N2, A refractive index difference (N1-N2) is set to 0.05 or more and 0.25 or less. By setting the refractive index difference (N1−N2) at a wavelength of 589 nm within the above range, a large refractive index difference is set for light in the visible light region between the high refractive index layer 31 and the low refractive index layer 32. and can reliably block (reflect) light in the visible region to the greatest extent possible.

The wavelength region of visible light that blocks (reflects) light in the visible light region to the maximum and blocks light that is not reflected to the minimum is the resin material contained in each of the high refractive index layer 31 and the low refractive index layer 32. , the number of repetitions of the high refractive index layer 31 and the low refractive index layer 32 in the reflective layer 3 (repeated portion 33), and the thickness of the reflective layer 3 (repeated portion 33), etc. can be set as appropriate. is adjusted to the size (within range) of

Therefore, when the mirror film 1 having the reflective layer 3 is attached to, for example, a translucent cover member of a display unit of a vehicle-mounted display device, light emitted from the display unit provided inside the display device will emit light. When the image light is transmitted through the mirror film 1, the light in the visible light region is reflected by the mirror film 1, and the remaining light, that is, the light that is not reflected, is attenuated and emitted to the outside of the display device. Become. As a result, when an image is viewed in the vehicle, visible light components that reduce visibility are prevented from entering the eyes, and the recognizability of the image viewed by the passenger can be improved. In addition, when the mirror film 1 is attached to a lens of sports eyewear, for example, external light emitted from the outside of the eyewear, that is, direct sunlight and its reflected light are reflected by the mirror. When passing through the film 1, the light in the visible light region is reflected by the mirror film 1, and the remaining light, ie the light that is not reflected, is attenuated and reaches the eyes of the wearer of the eyewear. As a result, visible light included in direct sunlight and reflected light is suppressed from entering the eyes, and thus the wearer's recognizability of an object visually recognized can be improved. Thus, the mirror film 1 functions as a reflector. An optical component (optical component of the present invention) is composed of the translucent cover member or the lens and the reflective layer 3 attached thereto.

The reflective layer 3 (multilayer laminate film) is obtained by forming the repeating portion 33 (laminate) in which the high refractive index layers 31 and the low refractive index layers 32 are alternately laminated as described above. More specifically, for example, it can be produced as follows.

That is, first, as the resin compositions for forming the high refractive index layer 31 and the low refractive index layer 32, a resin material having a high refractive index for light in the visible light region and a resin material having a high refractive index for light in the visible light region On the other hand, by preparing a material containing a resin material with a low refractive index as a main material and alternately laminating these, a repeating portion in which the high refractive index layer 31 and the low refractive index layer 32 are alternately laminated 33 (laminate) is obtained (laminating step).

The method for obtaining this repeating portion 33 is not particularly limited, but for example, a feed block method in which the resin material as a raw material is melt-extruded by several extruders, a co-extrusion T-die method such as a multi-manifold method, An air-cooled or water-cooled co-extrusion inflation method can be mentioned, and among them, the co-extrusion T-die method is particularly preferred. The co-extrusion T-die method is preferably used because it is excellent in controlling the thickness of each layer to be formed.

Next, the repeated portion 33 (laminate) in which the high refractive index layers 31 and the low refractive index layers 32 are alternately laminated is cooled, dried and solidified (cooling step). As a result, the reflective layer 3 functioning as a multilayer laminated film (multilayer laminated reflector) that selectively reflects light in the visible light region and transmits light that is not reflected as transmitted light is obtained.

Here, when the mirror film 1 is applied to an in-vehicle display device or sports eyewear, it is assumed that the mirror film 1 will be used under severe conditions. Therefore, the reflective layer 3 of the mirror film 1 is required to have excellent heat resistance.

As described above, the reflective layer 3 exhibits the characteristic of reflecting light in the visible light region to the maximum extent and transmitting the light that is not reflected to the maximum extent. Therefore, it can be said that the reflective layer 3 exhibits excellent heat resistance when the properties of the reflective layer 3 are preferably maintained even when exposed to severe conditions.

Therefore, in the present invention, the main material of the high refractive index layer 31 and the main material of the low refractive index layer 32, which constitute the reflective layer 3, have a refractive index of Let Tg1 be the glass transition point of a resin material with a high refractive index, and Tg2 be the glass transition point of a resin material with a low refractive index for light in the visible light region contained in the low refractive index layer 32, Tg1, Tg2≧105° C. satisfied with the relationship. Thus, by selecting a material having both Tg1 and Tg2 of 105° C. or higher, both the high refractive index layer 31 and the low refractive index layer 32 can have excellent heat resistance. Therefore, it is possible to appropriately suppress or prevent a change in the thickness of the refractive index layer having a lower glass transition point out of the low refractive index layer 32 and the high refractive index layer 31 . Therefore, the reflective layer 3 of the mirror film 1 exhibits excellent heat resistance because the deterioration of its function as a reflective plate is accurately suppressed or prevented. The resin material with a low refractive index in the low refractive index layer 32 is generally selected to have a lower glass transition point than the resin material with a high refractive index contained as the main material of the high refractive index layer 31. high tendency. Therefore, by using a resin material having a low refractive index and a glass transition point Tg2 of 105° C. or higher, the above effects can be reliably exhibited.

This reflective layer 3 is 10 degrees higher than the glass transition point Tg1 of the main material forming the high refractive index layer 31 and the glass transition point Tg2 of the main material forming the low refractive index layer 32, whichever is higher. C. The reflectance of light at a wavelength of 589 nm of the curved laminate obtained when the repeated portion 33 (laminate) is formed into a curved laminate having a curved shape with a curvature radius of 60 mm by pressing against a metal mold at a temperature higher than ° C. R1 [%], and after storing this curved laminate in a heat circulation oven for 1000 hours in a temperature environment of 105 ° C., when the reflectance of the curved laminate with a wavelength of 589 nm is R2 [%] , R2/R1×100[%] is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more.

As described above, even if the repeated portion 33 (curved laminate) having a curved shape with a curvature radius of 60 mm is exposed to the severe condition of being stored in a temperature environment of 105° C. for 1000 hours, the reflectance is maintained. The properties are maintained at or above the lower limit. As described above, since the reflectance retention is maintained at a rate equal to or higher than the lower limit, it can be said that the reflective layer 3 exhibits excellent heat resistance. Also, the reflectance R1 of the curved laminate for light with a wavelength of 589 nm is preferably 40% or more, and more preferably 45% or more and 70% or less. It can be said that such a curved laminated body reflects light in the visible light region with excellent reflectance.

As described above, in the repeating portion 33 (laminate), the visible light wavelength region that blocks (reflects) light in the visible light region to the maximum and blocks non-reflected light to the minimum is the high refractive index layer. 31 and the low refractive index layer 32, the number of repetitions of the high refractive index layer 31 and the low refractive index layer 32 in the reflective layer 3 (repeated portion 33), and the reflective layer 3 (repeated portion 33 ) can be adjusted to a desired size (within a range) by appropriately setting the thickness and the like.

Specifically, in the present invention, the sodium D line (589 nm), which is generally used as a reference wavelength of visible light, is used as a representative value in such a reflective layer 3 (repeated portion 33), and a high By defining the magnitude of the refractive index difference (N1−N2) between the refractive index N1 of the refractive index layer 31 and the refractive index N2 of the low refractive index layer 32 to be 0.05 or more and 0.25 or less, the reflective layer 3 ( The repeating portion 33), that is, the reflective polarizing plate, can reflect light in the visible light range, specifically, visible light in the wavelength range of 400 nm to 780 nm to the maximum.

Furthermore, in the present invention, as the main material of the high refractive index layer 31 and the main material of the low refractive index layer 32, a glass transition of a resin material having a high refractive index for light in the visible light region contained in the high refractive index layer 31 A point Tg1 and a glass transition point Tg2 of a resin material having a low refractive index with respect to light in the visible light region included in the low refractive index layer 32 are selected so as to satisfy the relationship of Tg1, Tg2≧105° C. Thus, the reflective layer 3 (repeated portion 33), that is, the reflective plate (multilayer laminated reflective plate) can exhibit excellent heat resistance.

As described above, the main material of the high refractive index layer 31, that is, visible As the resin material having a high refractive index for light in the optical region and the main material of the low refractive index layer 32, that is, the resin material having a low refractive index for light in the visible region, polycarbonate having amorphous properties is used. It is preferably at least one of polystyrene resin, polyether resin, styrene resin, polyester resin and acrylic resin, and polycarbonate resin, polyether resin and polyester resin. At least one is more preferable. By appropriately selecting the main materials of the high refractive index layer 31 and the low refractive index layer 32 from these materials, the reflective layer 3 including the high refractive index layer 31 and the low refractive index layer 32 can be relatively easily formed with a refractive index of Both the difference (N1-N2) being 0.05 or more and 0.25 or less and Tg1, Tg2≧105° C. can be satisfied.

Considering the above points, the main material of the high refractive index layer 31 is polyester resin such as polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone ( PES) and at least one of polyarylates (PAR) are preferably selected.

Main materials of the low refractive index layer 32 include polyester resins such as polycarbonate (PC), polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and acrylic resins such as polymethyl methacrylate (PMMA). , polystyrene (PS), styrenic resin such as acrylonitrile-styrene copolymer (AS), and polyarylate (PAR) are preferably selected.

When such a resin material is used, the combination of the main materials contained in the high refractive index layer 31 and the low refractive index layer 32 includes, specifically, polycarbonate (PC) and polymethyl methacrylate (PMMA). a combination of polyarylate (PAR) and polymethyl methacrylate (PMMA), a combination of polyethylene terephthalate (PET) and polymethyl methacrylate (PMMA), a combination of polyether sulfone (PES) and polyarylate (PAR ), a combination of polyethylene naphthalate (PEN) and acrylonitrile-styrene copolymer (AS), a combination of polyethylene naphthalate (PEN) and polymethyl methacrylate (PMMA), and the like. According to such a combination, both of the refractive index difference (N1-N2) being 0.05 or more and 0.25 or less and Tg1, Tg2≧105° C. are surely satisfied. be able to.

The high refractive index layer 31 and the low refractive index layer 32 may each contain an additive such as a filler in addition to the main material. Thereby, the reflective layer 3 including the high refractive index layer 31 and the low refractive index layer 32 has a refractive index difference (N1−N2) of 0.05 or more and 0.25 or less, and Tg1, Tg2≧105° C. Both can be more certainly satisfying.

The filler is not particularly limited, but examples include inorganic fillers such as silica, alumina, calcium carbonate, strontium carbonate, calcium phosphate, kaolin, talc, smectite, crosslinked polystyrene, and styrene-divinylbenzene copolymer. Among them, one or more of them can be used in combination. Among them, at least one of strontium carbonate and smectite is preferable, and strontium carbonate is It is more preferable to have

In addition, the filler may be in the form of particles such as spheres or flattened particles, granules, pellets, or flakes, but is preferably contained in the form of particles.

In the high refractive index layer 31 and the low refractive index layer 32 obtained by combining the resin materials as described above, the glass transition point Tg1 of the resin material having a high refractive index for light in the visible light region and the light in the visible light region The glass transition point Tg2 of a resin material having a low refractive index relative to The lower Tg1 and Tg2 preferably satisfy the relationship of 110°C to 250°C, and the lower Tg1 and Tg2 more preferably satisfy the relationship of 110°C to 200°C. Further, it preferably satisfies the relationship 0°C≤|Tg1-Tg2|≤60°C, and more preferably satisfies the relationship 25°C≤|Tg1-Tg2|≤60°C. In this way, both Tg1 and Tg2 are within the above range, and furthermore, by selecting the one in which the difference between the two is equal to or less than the above upper limit value, both the high refractive index layer 31 and the low refractive index layer 32 can have excellent heat resistance, the reflective layer 3 can reliably exhibit excellent heat resistance.

Furthermore, the refractive index difference (N1-N2), which is a relational expression between the refractive index N1 of the high refractive index layer 31 at a wavelength of 589 nm and the refractive index N2 of the low refractive index layer 32 at a wavelength of 589 nm, is 0.05 or more. Although it may be 0.25 or less, it is preferably 0.08 or more and 0.25 or less. The high refractive index layer 31 preferably has a refractive index N1 of 1.57 or more and 1.85 or less at a wavelength of 589 nm, and the low refractive index layer 32 preferably has a refractive index N2 of 1.49 or more at a wavelength of 589 nm. It is preferably 1.67 or less. This makes it possible to more reliably reflect light in the visible light region.

Furthermore, the high refractive index layer 31 and the low refractive index layer 32 each preferably have an average thickness of 50 nm or more and 300 nm or less, more preferably 70 nm or more and 200 nm or less. In the average thickness within this range, the optical thickness of the high refractive index layer 31 and the low refractive index layer 32 (average thickness of the layer × refractive index of the layer) is determined by the wavelength of light in the visible light region to be selectively reflected. set to 1/4 the size of the . As a result, the light reflected at the interface can be strengthened with each other, so that the reflective layer 3 can selectively reflect light in the visible light region.

In addition, in the repeating portion 33 in which the high refractive index layer 31 and the low refractive index layer 32 are laminated, the number of laminated layers is preferably 50 or more and 750 or less, more preferably 100 or more and 600 or less. is more preferred.

By setting the average thickness of the high refractive index layer 31 and the low refractive index layer 32 and the number of the repeating portions 33 in which the high refractive index layer 31 and the low refractive index layer 32 are laminated within the above range, The wavelength of light that is maximally blocked in the optical region (wavelength region) can be adjusted to a desired size (within a range).

As shown in FIG. 1, the hard coat layer 5 is formed on both the upper surface and the lower surface of the reflective layer 3 and is composed of an ultraviolet curable resin. It is provided to provide excellent weather resistance, durability, scratch resistance, and thermoformability. The mirror film 1 having the hard coat layer 5 can be attached to a window or the like provided in the container in a curved state, for example.

Examples of the ultraviolet curable resin constituting the hard coat layer 5 include an ultraviolet curable resin containing an acrylic compound as a main component, an ultraviolet curable resin containing a urethane acrylate oligomer or a polyester urethane acrylate oligomer as a main component, and an epoxy resin. , vinylphenol-based resins and the like as a main component. Among these, an ultraviolet curable resin containing an acrylic compound as a main component is preferable. Thereby, the adhesion with the reflective layer 3 can be improved.

The average thickness of the hard coat layer 5 is not particularly limited. As a result, the function as a coat layer that protects the reflective layer 3 can be reliably imparted.

The refractive index of the hard coat layer 5 is not particularly limited. For example, it is preferably from 1.40 to 1.60, more preferably from 1.450 to 1.595.

The hard coat layer 5 is formed by, for example, applying a varnish-like ultraviolet curable resin composition on the reflective layer 3 to form a liquid coating, and curing the liquid coating by irradiating the liquid coating with ultraviolet rays. It is formed.

The mirror film 1 may omit the formation of the hard coat layer 5, that is, the mirror film 1 may be composed of the reflecting layer 3 (the reflecting plate of the present invention) alone.

The mirror film 1 configured as described above preferably has a total thickness of, for example, 10 μm or more and 200 μm or less, more preferably 20 μm or more and 120 μm or less. As a result, the mirror film 1 can be made as thin as possible, and the mirror film 1 can be made rigid enough to withstand normal use.

The mirror film 1 has a rectangular shape in plan view, preferably 50 mm or more and 200 mm or less in length, more preferably 60 mm or more and 190 mm or less in width, and 100 mm or more and 400 mm or less in width. is preferable, and 130 mm or more and 380 mm or less is more preferable.

Although the reflector and the optical component of the present invention have been described above, the present invention is not limited to this, and each layer constituting the mirror film 1 having the reflector as the reflective layer 3 exhibits the same function. It can be replaced with any possible configuration. Moreover, the mirror film 1 may further include other layers such as an intermediate layer.

Furthermore, in the above-described embodiment, the case where the reflector of the present invention is applied to the mirror film 1 provided as the reflective layer 3 (multilayer laminated reflector) has been described. In addition to being attached to a cover film provided in a display device such as a display, sunglasses, and lenses provided in eyewear such as spectacles, the reflector of the present invention can be used for motorcycles, cars, aircraft, and railways. Such moving means, machine tools, window members provided in buildings, headlights, cover members provided in fog lamps, brightness enhancement films and cold mirrors provided in the light sources provided in head-up displays, and in-vehicle sensors such as infrared sensors. It can be used by attaching it to a reflector or the like. The reflector of the present invention satisfies both the refractive index difference (N1-N2) of 0.05 or more and 0.25 or less and Tg1, Tg2≧105° C. as described above, and is excellent. Since it exhibits excellent heat resistance, it can be suitably used as a reflector provided in various optical members, and various optical members exhibit excellent reliability.

EXAMPLES The present invention will now be described more specifically based on examples. In addition, the present invention is not limited at all by these examples.

1. Preparation of raw materials <Polycarbonate (PC1)>
Iupilon E2000 (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was prepared as polycarbonate (PC1).

<Polymethyl methacrylate (heat-resistant PMMA1)>
Delpet PM120N (manufactured by Asahi Kasei Corporation) was prepared as polymethyl methacrylate (heat-resistant PMMA1).

<Polyethylene terephthalate (heat-resistant PETG1)>
Tritan TX2001 (manufactured by Eastman Chemical Co., glycol-modified polyethylene terephthalate) was prepared as a heat-resistant amorphous polyethylene terephthalate (heat-resistant PETG1).

<Polyethylene terephthalate (PETG2)>
Skygreen K2012 (manufactured by SK Chemicals) was prepared as an amorphous polyethylene terephthalate copolymer (PETG2).

<Polyarylate (PAR1)>
As polyarylate (PAR1), U polymer P-5001 (manufactured by Unitika Ltd.) was prepared.

<Polyethersulfone (PES)>
Sumika Excel 3600G (manufactured by Sumitomo Chemical Co., Ltd.) was prepared as polyether sulfone (PES).

<Polyethylene naphthalate (PEN1)>
Teonex TN8065S (manufactured by Teijin Limited) was prepared as polyethylene naphthalate (PEN1).

<Polyethylene terephthalate (APET1)>
Novapex GM700Z (manufactured by Mitsubishi Chemical Corporation, crystalline polyethylene terephthalate) was prepared as polyethylene terephthalate (APET1).

<Acrylonitrile-styrene copolymer (AS1)>
As the acrylonitrile-styrene copolymer (AS1), Denka AS-XGS (manufactured by Denka Co., Ltd.) was prepared.

<Styrene-N-phenylmaleimide-maleic anhydride copolymer (IP1)>
As the styrene-N-phenylmaleimide-maleic anhydride copolymer (IP1), Denka IP-ND (manufactured by Denka Co., Ltd.) was prepared.

2. Manufacture of multilayer laminated reflector (Example 1)
[1] First, polycarbonate (PC1) is prepared as a resin material for forming the high refractive index layer 31, and polymethyl methacrylate (heat-resistant PMMA1) is prepared as a resin material for forming the low refractive index layer 32. did.

[2] Next, polycarbonate (PC1, Tg 150°C) and polymethyl methacrylate (heat-resistant PMMA1, Tg 123°C) were each extruded at 270°C with an extruder (manufactured by SunNT Co., Ltd., "SNT40-28"). and co-extruded using a feed block and a die to form a film, and then cooled to laminate the high refractive index layers 31 and the low refractive index layers 32 alternately and repeatedly. , a reflector (multilayer laminated reflector) of Example 1 composed of a laminate of 1023 layers in total (511 repetitions) was obtained. Here, the ejection amount was adjusted so that the lamination thickness ratio was high refractive index layer 31:low refractive index layer 32=1:1.

In the obtained reflector (laminate), the refractive index of the low refractive index layer 32 at a wavelength of 589 nm was measured using an Abbe refractometer (manufactured by ATAGO, "NA-1T SOLID"). was 510. The refractive index of the high refractive index layer 31 at a wavelength of 589 nm was 1.585 when measured using an Abbe refractometer (manufactured by ATAGO, "NA-1T SOLID"). Furthermore, the average thickness of the reflector was 100 μm.

(Examples 2 to 6, Comparative Examples 1 to 3)
In the step [1], the resin materials for forming the high refractive index layer 31 and the low refractive index layer 32 were prepared in the same manner as in Example 1 except that the resin materials shown in Table 1 were prepared. Multilayer laminated reflectors of Examples 2 to 6 and Comparative Examples 1 to 3 were obtained.

3. Evaluation The reflectors of each example and each comparative example were evaluated by the following methods.

<1A> Measurement of Reflectance R1 (%) of Reflector Plate Before Heating By pressing against a metal mold at a temperature 10° C. higher than the point, the reflector (laminate) was formed into a curved laminate having a curved shape with a curvature radius of 60 mm.

Next, a curved reflecting plate (curved laminate) is placed between the light source emitting light of 589 nm and the light receiving portion so that the angle between the upper surface of the reflecting plate and the straight line connecting the light source and the light receiving portion is 90. °.

Next, the emitted light (transmitted light) emitted from the light source and transmitted through the curved reflecting plate is received by the light receiving unit, and the transmittance (%) of this transmitted light is measured. ), the reflectance R1 (%) was determined.

<2A> Measurement of Reflectance R2 (%) of Reflector After Heating By pressing against a metal mold at a temperature 10° C. higher than the point, the reflector (laminate) was formed into a curved laminate having a curved shape with a curvature radius of 60 mm.

Next, the curved reflecting plate (curved laminate) is stored in a thermal circulation oven under a temperature environment of 105° C. for 1000 hours, after which reflection occurs between the light source emitting light of 589 nm and the light receiving part. The plate was arranged so that the angle formed by the upper surface of the plate and the straight line connecting the light source and the light receiving section was 90°.

Next, the emitted light (transmitted light) emitted from the light source and transmitted through the curved reflecting plate is received by the light receiving unit, and the transmittance (%) of this transmitted light is measured to obtain the reflection after heating. A rate R2 (%) was obtained.

Then, the reflectance retention ( R2/R1×100 [%]) was obtained.

<3A> Confirmation of Heat Resistance of Reflector in Visible Light Region First, the reflectance at a wavelength of 590 nm was measured for the reflector of each example and each comparative example. After that, a durability test (105° C.×1000 hr) was performed, and the reflectance of the sample (reflector plate) after the test was similarly measured.

Then, when the reflectances before and after the endurance test were R3 and R4, respectively, the rate of change in reflectance was determined as follows.

Change rate of reflectance: R4/R3×100 (%)
After that, the obtained rate of change in reflectance was evaluated based on the evaluation criteria shown below.

[Evaluation criteria]
◎: R4/R3 × 100 is 85% or more ○: R4/R3 × 100 is 80% or more and less than 85% ×: R4/R3 × 100 is less than 80%

<4A> Confirmation of Transmittance and Heat Resistance of Reflector in Infrared Region First, the transmittance at a wavelength of 900 nm was measured for the reflector of each example and each comparative example. After that, a durability test (105° C.×1000 hr) was performed, and the transmittance of the sample (reflector) after the test was similarly measured.

Then, when the transmittances before and after the endurance test were T3 and T4, respectively, the rate of change in transmittance was determined as follows.

Transmittance change rate: T4/T3×100 (%)
After that, the obtained rate of change in transmittance was evaluated based on the following evaluation criteria.

[Evaluation criteria]
◎: T4 / T3 × 100 is 85% or more ○: T4 / T3 × 100 is 80% or more and less than 85% ×: T4 / T3 × 100 is less than 80%

<5A> Confirmation of thermal bendability of the reflector First, for each of the reflectors of Examples and Comparative Examples, the glass transition point was higher than the glass transition point Tg1 or the glass transition point Tg2, whichever was higher by 10°C. While being heated to a temperature, it was subjected to thermal bending by being pressed against a metal mold having a radius of curvature of 60 mm.
Then, the thermally bent reflector was evaluated based on the following evaluation criteria.

[Evaluation criteria]
◎: The radius of curvature of the thermally bent reflector is 55 mm or more and 60 mm or less ○: The radius of curvature of the thermally bent reflector is 50 mm or more and less than 55 mm ×: The radius of curvature of the thermally bent reflector is less than 50 mm

Table 1 below shows the evaluation results of the reflectors of Examples and Comparative Examples obtained as described above.

As shown in Table 1, the reflector in each example satisfies Tg1 and Tg2≧105° C. and the refractive index difference (N1−N2) is 0.05 or more and 0.25 or less. Therefore, before the heat resistance test, it exhibits excellent reflectivity in the visible light region, and before and after the heat resistance test, while maintaining reflectivity in the visible light region, it maintains transparency in the infrared region. A possible result, that is, a result that can be said to have heat resistance was shown.

On the other hand, the reflectors of the respective comparative examples satisfy at least one of Tg1, Tg2≧105° C. and the refractive index difference (N1−N2) being 0.05 or more and 0.25 or less. Therefore, it cannot be said that it has one or both of excellent reflectivity in the visible light region and heat resistance.

REFERENCE SIGNS LIST 1 mirror film 3 reflective layer 5 hard coat layer 31 high refractive index layer 32 low refractive index layer 33 repeating part

Claims (8)

A reflector plate comprising a laminate in which high refractive index layers and low refractive index layers are alternately and repeatedly laminated,
The refractive index of the high refractive index layer is higher than the refractive index of the low refractive index layer,
where Tg1 is the glass transition point of the main material forming the high refractive index layer and Tg2 is the glass transition point of the main material forming the low refractive index layer, Tg1 and Tg2≧105° C.;
The refractive index difference (N1−N2) is 0.05 or more and 0.05 or more, where N1 is the refractive index of the high refractive index layer at a wavelength of 589 nm and N2 is the refractive index of the low refractive index layer at a wavelength of 589 nm. is 25 or less ,
When the laminated body is formed into a curved laminated body having a curved shape with a curvature radius of 60 mm at a temperature 10° C. higher than the higher glass transition point of the glass transition point Tg1 and the glass transition point Tg2 R1 [%] is the reflectance of light with a wavelength of 589 nm of the curved laminate,
After the curved laminate is stored in a thermal circulation oven in a temperature environment of 105° C. for 1000 hours, R2/R1× A reflector having a reflectance retention of 80% or more, which is required at 100[%] . 2. The reflector according to claim 1 , wherein said curved laminate has a reflectance R1 of 40% or more for light with a wavelength of 589 nm. 3. The reflector according to claim 1, wherein in the laminate, the number of repetitions in which the high refractive index layers and the low refractive index layers are alternately laminated is 50 times or more and 750 times or less. 4. The reflector according to claim 1 , wherein the glass transition point Tg1 and the glass transition point Tg2 satisfy a relationship of 0.degree. C..ltoreq.|Tg1-Tg2|.ltoreq.60.degree. The reflector according to any one of claims 1 to 4 , wherein the glass transition point Tg1 and the glass transition point Tg2, whichever is lower, is 110°C or higher and 250°C or lower. 6. The reflector according to claim 1 , wherein the high refractive index layer has a refractive index N1 of 1.57 or more and 1.85 or less at a wavelength of 589 nm. 7. The reflector according to claim 1, wherein the low refractive index layer has a refractive index N2 of 1.49 or more and 1.67 or less at a wavelength of 589 nm. An optical component comprising the reflector according to any one of claims 1 to 7 .

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