JP2007271857A - Fresnel lens, its manufacturing method and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Fresnel lens which is excellent in heat resistance, durability and optical performance, its manufacturing method with high productivity, a light gathering solar battery system and the like using the same. <P>SOLUTION: The Fresnel lens has a Fresnel lens mold layer (A) and a transparent supporting base (B). The Fresnel lens which is characterized in that the Fresnel lens mold layer (A) is constructed by forming fine pattern threads of the Fresnel lens by pouring a transparent liquid silicone resin into a flexible resin mold with a sawtooth fine pattern and hardening. The manufacturing method of the lens and the light gathering solar battery system and the like, using the lens are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a Fresnel lens, a manufacturing method thereof, and an application thereof, and more specifically, a Fresnel lens having a Fresnel lens molding layer (A) and a transparent support substrate (B), a manufacturing method thereof, and a condensing type using the same. The present invention relates to a solar cell device and the like.

Conventionally, Fresnel lenses have been manufactured by a mold-molding method by heating and pressurizing a thermoplastic resin or the like using a mold, but in this method, after the thermoplastic resin is heated and stamped, it is thermally deformed. Since it is necessary to cool below the temperature, there is a drawback that it takes time for molding.
Furthermore, since the mold is also exposed to a high temperature, the surface of the mold is oxidized and the prism shape of the Fresnel lens is changed, which causes a problem that the reproducibility of the Fresnel lens is deteriorated.
For this reason, in recent years, a method has been adopted in which a lens mold that can be manufactured under relatively mild conditions is filled with ultraviolet or electron beam curable resin, and the resin is cured and molded. . This method has the advantage of good production efficiency because it does not use temperature changes.

  However, this method using a curable resin requires the lamination of a transparent plastic film as a support substrate on one side of the curable resin in order to increase the strength of the Fresnel lens. Since the surface of the filled curable resin is coated with a transparent plastic film and then the resin is cured, the resulting Fresnel lens is prone to curl due to polymerization shrinkage of the curable resin, and the quality of the lens There is a problem in terms of manufacturing, and in terms of manufacturing, the yield is poor, and there is a problem that a post-process for curl correction is required. Also, when releasing the Fresnel lens from the mold, since a rigid substrate is laminated, it is difficult to release smoothly, which causes problems such as the formation of an opaque part on the surface of the Fresnel lens. There were often. In addition, since the support substrate and the curable resin are in direct contact with each other during production, depending on the type of resin constituting the support substrate, swelling or crazing may occur due to the influence of the ultraviolet curable resin or the electron beam curable resin. There was also an inconvenience that the selection of the resin was extremely limited.

Various Fresnel lenses have been proposed in order to deal with the above-described problems and defects. For example, a first curable material that is cured with ultraviolet rays or the like on a mold having a mold surface that is an inverted shape of the prism shape of the Fresnel lens. After filling the resin liquid and coating the surface of the filled resin liquid with a transparent film, the resin film is cured with ultraviolet rays or the like, and has the same or substantially the same polymerization shrinkage rate as the first curable resin. By applying a second curable resin liquid and then irradiating ultraviolet rays or the like, the first and second resin liquids are simultaneously cured and a prism shape of a Fresnel lens is formed on the first resin. A method of manufacturing a Fresnel lens by removing the post-molding die is disclosed (see Patent Document 1). Further, after applying a resin composition of ultraviolet ray or electron beam curable resin to a mold having a Fresnel lens surface shape, a resin layer is formed, and a light transmissive plastic film is laminated on the surface of the resin layer. The resin layer is cured by irradiating ultraviolet rays or electron beams from the surface, after which the cured resin layer and the plastic film are released from the mold, and then a transparent substrate is laminated on the plastic film surface to produce a Fresnel lens plate. A method for manufacturing a Fresnel lens plate is disclosed (see Patent Document 2).
However, these conventionally proposed Fresnel lenses and their manufacturing methods still have problems that are not sufficient in terms of Fresnel lens characteristics, particularly in terms of optical performance, heat resistance and durability, and in terms of production efficiency. is doing.

In recent years, Fresnel lenses have begun to be applied to various applications. For example, Fresnel lenses that collect sunlight and light collected by the Fresnel lenses are incident and guided while repeating internal reflection. A concentrating solar power generation device including a secondary condenser and a solar cell on which light output from the secondary condenser is incident (see, for example, Patent Documents 3 to 5), and a Fresnel lens as an LED element An illumination device (see, for example, Patent Document 6) characterized by being disposed almost directly above the light emitting surface, an outer lens having a diffusing lens cut for forming a light distribution, and the outer lens substantially It comprises an inner lens having a converging lens cut in the form of a Fresnel lens for allowing light to enter as parallel rays, and a plurality of LED lamps arranged with a predetermined area on the light source substrate. ED traffic lamp (for example, see Patent Document 7.) It has been proposed. Along with such trends of expansion of applications and downsizing of devices, high-performance Fresnel lenses that can withstand even more severe usage environments are required.
Japanese Examined Patent Publication No. 7-95121 Japanese Examined Patent Publication No. 6-92130 JP 2004-214470 A JP 2003-258291 A JP 2001-148501 A JP 2005-257993 A Japanese Patent Laid-Open No. 2003-030786

  In view of the above problems, an object of the present invention is a Fresnel lens excellent in optical performance, heat resistance and durability, a manufacturing method excellent in high productivity for obtaining the same, and a concentrating solar cell device using the same. And so on.

  As a result of intensive studies to solve the above problems, the inventors first applied a flexible thermoplastic sheet, so that a saw-shaped fine pattern of a Fresnel lens was obtained from a master mold. Obtain a transfer molded resin mold, and then pour a transparent liquid silicone resin into the resin mold to obtain a Fresnel lens molding layer that is formed by transferring a sawtooth-shaped fine pattern of a Fresnel lens, When a transparent support substrate is laminated on this, it has been found that a Fresnel lens having excellent heat resistance and durability and good optical performance can be obtained. As a result, it has been found that a Fresnel lens excellent in the above characteristics can be manufactured with high productivity while ensuring mass productivity. The present invention has been completed based on these findings.

That is, according to the first invention of the present invention, the Fresnel lens has a Fresnel lens molding layer (A) and a transparent support base (B), and the Fresnel lens molding layer (A) is a sawtooth-shaped fine layer. A Fresnel lens is provided by forming a fine pattern of Fresnel lens by pouring a transparent liquid silicone resin into a flexible resin mold having a pattern and curing it.
According to a second aspect of the present invention, there is provided the Fresnel lens according to the first aspect, wherein the liquid silicone resin is an addition-curable silicone resin.
Furthermore, according to the third invention of the present invention, there is provided the Fresnel lens according to the first or second invention, wherein the support base (B) is a glass plate.

According to a fourth invention of the present invention, in any one of the first to third inventions, the Fresnel lens molding layer (A) is further subjected to a glassy coating on the surface on which the fine pattern of the Fresnel lens is formed. A Fresnel lens is provided.
According to a fifth aspect of the present invention, in the fourth aspect, the vitreous coating material includes an alkoxy group, an acyloxy group, or an oxime as a main component composed of an organopolysiloxane having a methyl group and / or a phenyl group. There is provided a Fresnel lens characterized by comprising a crosslinking agent comprising an organosiloxane having at least one functional side chain of a group and a curing catalyst.
Furthermore, according to a sixth aspect of the present invention, there is provided the Fresnel lens according to the fourth aspect, wherein the vitreous coating material is perhydropolysilazane.

On the other hand, according to the seventh invention of the present invention, a saw-shaped fine pattern is transferred by applying heat-pressing a flexible thermoplastic sheet to a master mold having a saw-shaped fine pattern. A first step of obtaining a formed flexible resin mold, and a transparent liquid silicone resin is poured into the resin mold, and further, a transparent support base (B) is placed on the resin mold and thermally cured while being pressed. A second step of forming a Fresnel lens molding layer (A) formed by transferring the saw-shaped fine pattern strip and simultaneously bonding a transparent support substrate (B) to the Fresnel lens molding layer (A); And a third step of removing the resin mold. A method for producing a Fresnel lens according to the first invention is provided.
According to an eighth aspect of the present invention, in the seventh aspect, the surface of the Fresnel lens molding layer (A) on which the fine pattern is transferred is further provided with a glassy coating. A method for manufacturing a Fresnel lens is provided.
Furthermore, according to the ninth invention of the present invention, in the seventh or eighth invention, the thermoplastic sheet of the first step is made of a resin having a Vicat softening point higher than the thermosetting temperature of the second step. A featured Fresnel lens manufacturing method is provided.
Still further, according to a tenth invention of the present invention, in any one of the seventh to ninth inventions, the third step is demolding by bending and peeling a flexible resin mold. A method of manufacturing a Fresnel lens is provided.

According to an eleventh aspect of the present invention, there is provided a concentrating solar cell device characterized by using the Fresnel lens according to any one of the first to sixth aspects.
Furthermore, according to a twelfth aspect of the present invention, there is provided a light emitting diode (LED) light source illumination device comprising the Fresnel lens according to any one of the first to sixth aspects.

The Fresnel lens of the present invention has a Fresnel lens molding layer (A) and a transparent support substrate (B), and the Fresnel lens molding layer (A) is a flexible resin molding having a saw-like fine pattern. Since it is characterized by forming a fine pattern strip of a Fresnel lens by pouring a transparent liquid silicone resin into the mold and curing it, it exhibits the effects of excellent heat resistance, durability, and optical performance.
In addition, the manufacturing method of the Fresnel lens according to the present invention reverses and transfers the saw-shaped fine pattern of the master mold to a resin mold with a flexible thermoplastic sheet, and further converts the resin mold fine pattern into a liquid silicone resin. Since it is a method of reversing, transferring, and curing, any number of replicas can be easily obtained, and a high-productivity Fresnel lens manufacturing method can be provided while ensuring mass productivity.
Furthermore, by using the Fresnel lens of the present invention, it is possible to provide a concentrating solar cell device or a light emitting diode (LED) light source illumination device having durability and good performance.

The Fresnel lens of the present invention is a Fresnel lens having a Fresnel lens molding layer (A) and a transparent support base (B),
The Fresnel lens molding layer (A) is formed by pouring a transparent liquid silicone resin into a flexible resin mold having a saw-like fine pattern to form a fine pattern of a Fresnel lens. It is what.
Further, the manufacturing method of the Fresnel lens of the present invention is such that the saw-shaped fine pattern is transferred and formed by applying heat-pressing a flexible thermoplastic sheet to a master mold having a saw-shaped fine pattern. A first step to obtain a flexible resin mold, and a transparent liquid silicone resin is poured into the resin mold, and a transparent support base (B) is placed on the resin mold and thermally cured while being pressed. A second step of forming a Fresnel lens molding layer (A) formed by transferring the saw-shaped fine pattern strip and simultaneously bonding a transparent support substrate (B) to the Fresnel lens molding layer (A); And a third step of removing the resin mold.
Below, the component of a Fresnel lens, its manufacturing method, a use, etc. are demonstrated in detail.

1. Components of Fresnel lens (i) Fresnel lens molding layer (A)
As described above, the Fresnel lens molding layer (A) used in the present invention is prepared by pouring a transparent liquid silicone resin into a flexible resin mold having a saw-like fine pattern and curing it. It is characterized by forming a strip.
“Liquid” in the above-mentioned liquid silicone resin means that the cured material of the silicone resin itself is liquid, as well as a solution, dispersion, sol, paste, etc. containing the cured material, which can be poured into a resin mold. It means that it has only fluidity. In addition, the “curing material” in the liquid curable material means a material having a property of curing at room temperature or by heating, and the degree of “curing” is the rigidity and durability normally required for a Fresnel lens. It is a thing which can provide the property.

As the liquid silicone resin, a saw-toothed fine pattern formed on a flexible resin mold must be accurately copied, so that the viscosity is below a certain limit, for example, in the range of 300 to 150,000 mPa · s. It is preferable to have. Moreover, a solvent can be added to the extent that there is no bad influence of a solvent for viscosity adjustment. (Note that the liquid silicone resin used in the present invention includes those that become a rubber-like body having elasticity after curing, such as a curable silicone rubber oligomer.)
Further, as the liquid silicone resin, a curable liquid silicone resin is preferable, and in particular, a curable silicone rubber oligomer (thermosetting type, room temperature curing type) is preferably used from the viewpoints of peelability, mechanical strength and dimensional stability. In addition, the liquid resin having a low molecular weight is preferably used because it can be expected to have sufficient permeability. The viscosity of the resin is preferably in the range of 300 to 150,000 mPa · s, and more preferably in the range of 500 to 100,000 mPa · s.

Specifically, the curable liquid silicone resin preferably contains a methylsiloxane group, an ethylsiloxane group, or a phenylsiloxane group, and particularly preferably a curable dimethylsiloxane resin.
Further, as the curable liquid silicone resin, specifically, a liquid silicone resin comprising 30 to 90% by weight of a vinyl group-containing silicone resin made of an addition type silicone obtained by crosslinking the following A liquid and B liquid. It can be suitably used. For example, “KE1935” manufactured by Shin-Etsu Chemical Co., Ltd. containing silicone resin can be used.

In addition, examples of the liquid silicone resin include partially vulcanized silicone rubber, which is stopped in the middle without completing the vulcanization reaction, and the resulting product does not interfere with workability. It means a silicone rubber having a shape retaining property and a property that can be easily deformed by applying pressure. Therefore, by transferring the partially vulcanized silicone rubber into a flexible resin mold having a saw-like fine pattern by applying pressure, the fine pattern can be transferred in a finely inverted state as it is. This transfer is completed by curing in the next step.
The partially vulcanized silicone rubber can be obtained by the following method, for example. After blending other ingredients into the unvulcanized silicone rubber raw material as necessary, it is put into a mold, heated while pressing, and partially vulcanized. The conditions for this partial vulcanization vary depending on the type of silicone rubber. For example, in the case of addition-type liquid silicone rubber (two-component type), the vulcanization reaction is completed in about 8 hours at 20 ° C. However, since the vulcanization reaction is completed in about 1 hour at 60 ° C., the vulcanization reaction is stopped in less than half time so that the above properties can be imparted. When the reaction is stopped in this way, it is immediately stored in a cold place to prevent further vulcanization reaction from proceeding. In addition to the time, the progress of the partial vulcanization reaction can be controlled by adjusting the heating temperature and adding a reaction inhibitor.

  As the silicone rubber raw material used here, a commercially available heat-curing type or room-temperature curing type, one-component or two-component type, addition type or condensation type can be used. Other components include reaction inhibitors such as methylvinylcyclotetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, hydroperoxide; reinforcing silica, quartz powder, iron oxide, alumina, vinyl group-containing silicone resin And various additives such as pigments, heat-resistant agents, flame retardants, and adhesion improvers.

  As such partially vulcanized silicone rubber, specifically, trade name “TSE260-7U” (Toshiba Silicone Corp.), trade name “KE565K-U” (JIS A hardness 60; Shin-Etsu Chemical Co., Ltd.), etc. Can be used. The JIS A hardness shown here is the hardness after vulcanization is completed.

The saw-shaped fine pattern includes a saw-shaped cross section having a very fine pitch and a calculated angle, which is a feature of the Fresnel lens, so as to match a desired optical path and focal length. In other words, the mold surface, which is the reverse shape of the prism shape of the Fresnel lens, is formed in advance on a flexible resin mold to form a fine pattern.
Further, the amount of the liquid silicone resin poured may be an amount sufficient to cover the entire surface of the resin mold with the support base (B) placed on the resin mold after the pouring.

Furthermore, as an embodiment of the present invention, a glassy coating layer can be applied as a protective layer on the surface of the Fresnel lens molding layer (A) where the fine pattern stripe is formed. By forming the glassy coating layer, it is possible to obtain a Fresnel lens molding layer having the same durability as that of a conventional Fresnel lens without causing any fear of scratches.
As the coating has a fine saw shape, there is a risk that the height may be buried in normal painting. For example, if a coating material is applied to the resin mold in advance, it will penetrate the silicone resin surface and the pattern An osmotic coating can be formed, and the saw-like height will be substantially unchanged by penetration. Further, a finer coat can be formed by applying a top coat to the pattern osmotic cured coat.

A suitable example of the glassy coating layer is “HEATLESS GLASS” (trade name) sold by Homer Technology Co., Ltd. This “heatless glass” is, so to speak, a one-component type silica solution that forms an amorphous ceramic layer that is hard and has excellent adhesion to various substrates even at low temperature heating or room temperature drying. And this thing is comprised by three main ingredients, a crosslinking agent, and a curing catalyst, containing silicon component (SiO ₂ ) contains 40% or more in terms of conversion, and does not contain a solvent, water or hydroxyl group. is there. The main agent is an organopolysiloxane having a methyl group or a phenyl group, the crosslinking agent is an organosiloxane having a functional side chain such as an alkoxy group, an acyloxy group, or an oxime group, and the curing catalyst is Zn, Al Metal-containing organic compounds such as Co, Sn, and halogen.
Also, the curing mechanism is that the functional group of the main organoorganosiloxane is first hydrolyzed by moisture in the air to change to a hydroxyl group, and then the hydroxyl group of the organopolysiloxane is attacked by the functional group of the crosslinker organosiloxane. In addition, it is considered that a dealcoholization reaction is caused under the action of a curing catalyst to form a polysiloxane cured body that is a three-dimensional polymer compound. It becomes a metal alkoxide condensate by a so-called sol-gel method.

In forming a vitreous coating layer using this heatless glass, a uniform coating means such as a conventional spin coating can be employed.
Moreover, by using this heatless glass, it is possible to obtain a good workability and a surface vitrified at a relatively low temperature.

In the above description, the heatless glass is used as the material for forming the glassy coating layer. However, for example, an inorganic polymer such as perhydropolysilazane (PHPS, perhydropolysilazane) is also used. You can also. Perhydropolysilazane is a thermosetting inorganic silazane (ceramic precursor polymer) represented by the structural formula [SiH _a NH _b ] _n (where a is 1 to 3 and b is 0 or 1), Silica glass reacts with moisture in the atmosphere at room temperature by adding a small amount of an amine-based catalyst that promotes the reaction with moisture by firing in a hard layer of amorphous silicon nitride ceramics by firing at an atmosphere and temperature of Convert to. As such perhydropolysilazane, “AQUAMICA” (registered trademark) manufactured by AZ Electronic Materials Co., Ltd. is available. Of course, it is not restricted to these, Other ceramic precursor polymers etc. can also be used.
Further, by using this perhydropolysilazane, it is possible to obtain good workability and a vitrified surface at a relatively low temperature, as in the case of heatless glass.

(Ii) Transparent support substrate (B)
The transparent support substrate (B) used in the present invention is only required to be substantially transparent, and usually includes optical glass and plastic often used as a material for a Fresnel lens. From the viewpoint of scratch resistance, optical glass is preferred. By using the optical glass, a back side surface that is exactly the same as a conventional lens and does not have to worry about scratches can be obtained.
Examples of plastic materials include acrylic resins such as polymethyl methacrylate (polymethylmethacrylate, PMMA) used for optical lenses, polycarbonate, high-density polyethylene, polystyrene, vinyl chloride, polyacrylonitrile-styrene copolymers, Examples thereof include styrene-acrylic copolymers.

  The thickness of the transparent support substrate (B) can be selected as appropriate, but in order to obtain mechanical strength, the thickness is preferably about 1 to 10 mm, preferably about 2 to 4 mm.

  About joining of this transparent support substrate (B) and the said Fresnel lens molding layer (A), it joins the transparent support substrate (B) and the Fresnel lens molding layer (A) which is the hardened | cured material of liquid silicone resin. May use a primer.

2. 2. Manufacturing method of Fresnel lens Generally, as shown in FIG. 2, a Fresnel lens is a lens whose lens surface is not a continuous surface but a stepped shape, and can be considered as a concentric prism, compared to a normal concave lens or convex lens. Thus, there is an advantage that the thickness of the lens itself can be reduced. Fresnel lenses are rarely used in imaging optical systems, and are mainly used as condenser lenses that collect light in an illumination optical system.
In the Fresnel lens of the present invention, in the Fresnel lens 1 shown in FIG. 1, 2 is a transparent support substrate (B), 3 is a Fresnel lens molding layer (A), and 3 a is a sawtooth-shaped fine of the Fresnel lens. 2a is a bonding surface. The Fresnel lens molding layer (A) 3 is formed by pouring a transparent liquid silicone resin into a flexible resin molding die, and thermosetting, for example, heat pressing, to transfer and form a saw-shaped fine pattern strip 3a. The fine pattern strip 3a functions as a Fresnel lens surface.

As described above, the Fresnel lens of the present invention is formed by transferring a saw-shaped fine pattern by heat-pressing a flexible thermoplastic sheet using a master mold having a saw-shaped fine pattern. A first step to obtain a flexible resin mold, and a transparent liquid silicone resin is poured into the resin mold, and a transparent support base (B) is placed on the resin mold and thermally cured while being pressed. A second step of forming a Fresnel lens molding layer (A) formed by transferring the saw-shaped fine pattern strip and simultaneously bonding a transparent support substrate (B) to the Fresnel lens molding layer (A); And a third step of removing the resin mold, so that it can be manufactured (see FIG. 3).
In addition, as described above, the method for forming the glassy coating layer is characterized in that a glassy coating is further applied to the surface on which the fine pattern strip of the Fresnel lens molding layer (A) is transferred and formed. .
Hereinafter, each process will be described.

(I) First step:
In the method for producing a Fresnel lens of the present invention, the first step is to apply a heat-pressed flexible thermoplastic sheet to a saw-shaped fine pattern by applying a master mold having a saw-shaped fine pattern. Is a step of obtaining a flexible resin mold on which is formed by transfer.
As the thermoplastic sheet having flexibility, in order to obtain a flexible resin mold, the thermoplastic resin used is also flexible and has a Vicat that is higher than the thermosetting temperature in the second step. Any resin having a softening point is not particularly limited. For example, vinyl chloride resin, polyethylene resin, polypropylene resin, polystyrene resin, ABS resin, AS resin, polyamide resin, polyacetal resin, methacrylic resin, polycarbonate resin, fluororesin, Any of thermoplastic resins such as a polyester resin can be used.
A resin mold made of a resin having a Vicat softening point higher than the thermosetting temperature in the second step is an essential requirement in order not to be softened by the thermosetting treatment in the second step.
The Vicat softening point is a value measured according to JIS K7206.

In the third step, the flexible resin mold is obtained from the molded product obtained in the second step of the resin mold, the Fresnel lens molding layer (A), and the transparent support substrate (B). Is an essential requirement for obtaining a Fresnel lens in which a transparent support substrate (B) is bonded to the Fresnel lens molding layer (A). That is, the flexibility of the resin mold is a necessary requirement for further bending the resin mold and removing the resin mold from the molded body.
The master mold is engraved with a fine pattern as a reverse image of a saw-tooth fine pattern. The master mold is made of a metal having excellent rust resistance, workability, finish, dimensional accuracy, etc., and is processed by precise cutting or electric discharge machining.
Furthermore, on the surface of this master mold, in order to improve its releasability, a plating layer in which particles of a submicron fluorine resin are dispersed, for example, electroless nickel by Hikifune Co., Ltd. or Osaka Gas Chemical Co., Ltd. -It is desirable to apply PTFE dispersion plating.
In addition, the step of obtaining a flexible resin mold on which the saw-shaped fine pattern is transferred and formed by applying a master mold and heat pressing can be performed by a conventional method.

(Ii) Second step:
In the method for producing a Fresnel lens of the present invention, in the second step, a transparent liquid silicone resin is poured into the resin mold obtained in the first step, and a transparent support base (B) is placed thereon and pressed. By thermosetting, the Fresnel lens molding layer (A) formed by transferring the saw-shaped fine pattern is formed, and at the same time, the transparent support substrate (B) is bonded to the Fresnel lens molding layer (A). It is a process.

As a specific method of the second step, for example, a resin mold is placed on a heat press machine bed (fixed platen), and then a transparent liquid silicone resin is poured into the resin mold, and then, By placing a transparent support substrate and heat-pressing, a fresnel lens molding layer (A) in which the sawtooth-shaped fine pattern strip is transferred and formed from a liquid silicone resin is formed, and at the same time, by heat-pressing , A method of bonding a transparent support substrate (B) to a Fresnel lens molding layer (A), that is, a molded body comprising a resin mold, a Fresnel lens molding layer (A), and a transparent support substrate (B). It is the process of obtaining.
In addition, although the case where the resin mold was below was demonstrated above, in the actual process, the part of the process of a press hardening may be set vertically, and it is not limited to the above.
The transparent support substrate (B) may be subjected to a primer treatment or the like in order to strengthen the bonding with the Fresnel lens molding layer (A).

(Iii) Third step:
In the present invention, the third step is a step of removing the resin molding die from the molded body obtained in the second step, which comprises a resin molding die, a Fresnel lens molding layer (A), and a transparent support substrate (B). It is.
As described in the first step, the third step is characterized in that the flexible resin molding die is bent and peeled to remove the mold. By this step, the Fresnel lens molding layer (A) is formed. And a transparent support base (B) can be obtained.

  The manufacturing method of the Fresnel lens according to the present invention will be described with reference to a specific embodiment (see FIG. 3). First, in the first step, a master metal having a saw-like fine pattern on a loading platform which is a fixed plate of a heat press machine Place a mold on it, place a flexible thermoplastic sheet, for example a vinyl chloride resin plate, and heat press, for example, set the temperature of the heat press machine to 100 ° C. and press at a pressure of 200 kgf for 3 minutes. , And after cooling, the mold is removed to obtain a flexible resin mold on which the saw-shaped fine pattern is transferred.

Next, in the second step, the flexible resin molding die obtained in the first step is placed on the heat press machine bed (fixed platen), and then the saw-shaped fine pattern of the resin molding die is transferred. A transparent curable liquid silicone resin such as “KE1935” manufactured by Shin-Etsu Chemical Co., Ltd. is poured onto the forming surface, a transparent support substrate such as tempered glass is placed on the surface, and heat pressing is performed. Then, the temperature of the heat press is set to 70 ° C., and pressing is performed at a pressure of 50 kgf for 10 minutes, thereby forming a Fresnel lens molding layer (A) in which the sawtooth-shaped fine pattern is transferred from a liquid silicone resin. At the same time, the transparent support substrate (B) is bonded to the Fresnel lens molding layer (A), that is, the resin molding die and the Fresnel lens molding layer (A) are transparent. A step of obtaining a molded article made from a lifting board (B).
Note that a cushioning material having good thermal conductivity may be sandwiched between the fixed platen and the movable platen so that these members can be pressed uniformly.
In addition, if the air between the liquid silicone resin and the support substrate (B) cannot be completely eliminated, bubble marks will be formed. When these are overlapped, the air is gradually removed from one end to the other. However, it is preferable to exclude the air by superimposing them or by interposing a liquid having no influence such as water that can be dried and removed thereafter. Thereafter, the movable platen is raised and the joined state is taken out.

Further, as the third step, the flexible resin mold is bent and peeled between the flexible resin mold and the cured liquid silicone resin that becomes the Fresnel lens molding layer (A). By demolding.
At the same time, the Fresnel lens molding layer (A), which is a cured product of the liquid silicone resin, is in a state of being bonded to a transparent support substrate, for example, a glass plate, and as shown in FIG. 1, the Fresnel lens of the present invention. Will be obtained.
The glassy coating on the transfer formation surface of the Fresnel lens molding layer (A) is formed by applying a glassy precursor material to the transfer molding surface by, for example, a spine coating method.
In this way, the Fresnel lens of the present invention is manufactured. This simple production process enables mass production and has excellent cost performance.

3. Fresnel lens and use thereof The Fresnel lens of the present invention has heat resistance and durability, and exhibits an effect of excellent optical performance. Therefore, a concentrating solar cell device that is particularly demanding and requires durability. And a light emitting diode (LED) light source illumination device.
In addition, by applying to concentrating solar cell devices and light emitting diode (LED) light source lighting devices, concentrating solar cell devices and light emitting diode (LED) light source lighting devices maintain power generation efficiency and lighting efficiency over a long period of time. Demonstrate the action and effect.

  The Fresnel lens of the present invention has not only a concentrating solar cell device and a light emitting diode (LED) light source illumination device, but also an illumination device, an optical element or an optical element that uses an incandescent lamp as a light source in order to achieve the above-described effects The present invention can be used for an image display device using a screen, a transmissive screen lens, a rear projection screen, a rear projection image display device, and the like.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not particularly limited to these examples.
[Example 1] (First step: production of flexible resin mold)
As a master mold, a 200 mm long x 200 mm wide x 10 mm thick mold with a 0.5 mm wide pitch and a saw-shaped concentric Fresnel lens shape (convex type) with a height of 10 to 300 μm from the center to the outer periphery Was used. The material of the mold is brass with the surface plated with Ni.
In addition, as a thermoplastic sheet having flexibility, a transparent vinyl chloride resin “Press Plate TS-608A” (thickness 1 mm) manufactured by Takiron Co., Ltd. is used. By applying and heat-pressing a master mold having a lens shape (convex type), a flexible resin mold (concave type) in which a saw-shaped concentric Fresnel lens shape was transferred and formed was obtained. The specific work process and press conditions are as follows.
The master mold was placed on the heat press machine bed, and then a 1 mm-thick vinyl chloride resin plate was placed on the master mold. The temperature of the heat press was set to 100 ° C., and pressing was performed at a pressure of 200 kgf for 3 minutes. Then, after cooling, the mold was removed to obtain a flexible resin mold.

(Second step: formation of Fresnel lens molding layer (A) and bonding with transparent support substrate (B))
Next, by pouring a transparent liquid silicone resin into the resin mold obtained as described above, and further setting the transparent support base (B) on the resin mold and thermosetting it while pressing, a saw-shaped fine pattern strip is formed. A second step of forming the Fresnel lens molding layer (A) formed by transfer and simultaneously joining the transparent support substrate (B) to the Fresnel lens molding layer (A) was performed. The specific components, working steps and pressing conditions are as follows.
A vinyl chloride resin having a saw-shaped concentric Fresnel lens shape (concave type) having a length of 200 mm, a width of 200 mm, a thickness of 0.7 mm, a width of 0.5 mm, and a height of 10 to 300 μm from the center to the outer periphery. As a liquid silicone resin for forming a mold and a Fresnel lens molding layer (A), “KE1935” (viscosity: 80000 mPa · s JIS A hardness: 55) manufactured by Shin-Etsu Silicone Co., Ltd., and a transparent support base (B ) Tempered glass (colorless and transparent): 200 × 200 × 3 mmt.

First, the vinyl chloride resin mold is placed on a heat press machine bed (fixed platen), then a liquid silicone resin is poured into the resin mold and a tempered glass subjected to primer treatment is placed thereon. Further, a heat conductive silicone gel sheet was placed thereon, and a heat press was prepared.
Next, as a heat press, the temperature of the heat press machine was set to 70 ° C., and pressing was performed at a pressure of 50 kgf for 10 minutes. Thus, the 2nd process of forming a Fresnel lens molding layer (A) by thermosetting, and joining a transparent support substrate (B) to a Fresnel lens molding layer (A) simultaneously was performed.

(Third step: step of removing the resin mold)
The molded body comprising the resin mold obtained in the second step, the Fresnel lens molded layer (A) and the transparent support substrate (B) was cooled, and then the resin mold was removed from the molded body. However, at that time, a piece of the vinyl chloride resin mold was lifted and removed while being bent.
Thus, Fresnel lens A was obtained.

[Example 2]
On the surface of the Fresnel lens A obtained in Example 1 on which the saw-shaped concentric Fresnel lens shape is transferred and formed, a glassy coating is further applied using “polysilazane” to form a glass coating layer having a thickness of about 1 μm. Formed.
In this way, Fresnel lens B was obtained.

  When the above Fresnel lens B was applied to a solar cell device, the light was condensed and good power generation efficiency was obtained. Moreover, when it applied to the LED light source illuminating device, the parallel light ray was emitted and the favorable illumination efficiency was obtained. From these results, it was found that the Fresnel lens of the present invention can be suitably used for solar cell devices and LED light source illumination devices.

  Since the Fresnel lens of the present invention has the effect of having heat resistance, durability and excellent optical performance, the application of various Fresnel lenses, for example, a condensing type in which the use environment is severe and durability is required. Not only solar cell devices and light emitting diode (LED) light source illumination devices, but also illumination devices that use incandescent lamps as light sources, optical display elements or image display devices using optical elements, transmissive screen lenses, rear projection screens It can be used for rear projection image display devices.

It is sectional drawing which shows an example of the Fresnel lens of this invention. It is a figure explaining the conventional Fresnel lens. It is a figure which shows the manufacturing process of the Fresnel lens of this invention.

Explanation of symbols

1 Fresnel lens 2 Transparent support substrate 2a Bonding surface (adhesive, primer)
3 Liquid silicone resin 3a Saw-like fine pattern of Fresnel lens

Claims (12)

A Fresnel lens having a Fresnel lens molding layer (A) and a transparent support base (B),
The Fresnel lens molding layer (A) is formed by pouring a transparent liquid silicone resin into a flexible resin mold having a saw-like fine pattern to form a fine pattern of a Fresnel lens. A Fresnel lens.   The Fresnel lens according to claim 1, wherein the liquid silicone resin is an addition-curable silicone resin.   The Fresnel lens according to claim 1 or 2, wherein the support base (B) is a glass plate.   4. The Fresnel lens according to claim 1, wherein the Fresnel lens molding layer (A) is formed by further applying a glassy coating to the surface of the Fresnel lens on which the fine pattern is formed.   The glassy coating material includes a main agent composed of an organopolysiloxane having a methyl group and / or a phenyl group, a crosslinking agent composed of an organosiloxane having at least one functional side chain of an alkoxy group, an acyloxy group or an oxime group. The Fresnel lens according to claim 4, comprising: a curing catalyst.   The Fresnel lens according to claim 4, wherein the glassy coating material is perhydropolysilazane.   The flexible thermoplastic sheet is obtained by applying a master mold having a saw-like fine pattern and heat-pressing the flexible thermoplastic sheet to obtain a flexible resin mold in which the saw-like fine pattern is transferred and formed. In one step, a transparent liquid silicone resin is poured into the resin mold, and a transparent support base (B) is placed on the resin mold and thermally cured while being pressed, whereby the saw-shaped fine pattern strip is transferred and formed. A second step of forming a Fresnel lens molding layer (A) and simultaneously bonding a transparent support substrate (B) to the Fresnel lens molding layer (A), and a third step of removing the resin molding die. The manufacturing method of the Fresnel lens of Claim 1 characterized by the above-mentioned.   The method for producing a Fresnel lens according to claim 7, wherein a glassy coating is further applied to a surface of the Fresnel lens molding layer (A) on which the fine pattern strip is transferred and formed.   The method for producing a Fresnel lens according to claim 7 or 8, wherein the thermoplastic sheet in the first step is made of a resin having a Vicat softening point higher than a thermosetting temperature in the second step.   The method for producing a Fresnel lens according to any one of claims 7 to 9, wherein the third step is to remove the mold by bending and peeling a flexible resin mold.   A concentrating solar cell device comprising the Fresnel lens according to claim 1.   A light emitting diode (LED) light source illumination device comprising the Fresnel lens according to claim 1.

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