JP2021085933A - Method of manufacturing light control filter - Google Patents

Abstract

To provide a method of manufacturing an optical control filter capable of improving the manufacturing yield even in the optical control filter in which fine light transmission parts are arrayed at high density.SOLUTION: A method of manufacturing a light control filter includes the steps of: using a molding mold 100 equipped with a circular substrate 110 in a plan view, and a plurality of projections 120 rising from the surface of the substrate 110; curing a liquid resin L after the liquid resin L is injected into the molding mold 100 so as to be brought into contact with the plurality of projections 120; forming a light control filter 10 in which a through hole 12 corresponding to the plurality of projections 120 is formed; and demolding the light control filter 10.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method for manufacturing an optical control filter.

Conventionally, an optical control filter for adjusting the light transmittance and the viewing angle has been known. For example, Patent Document 1 includes a photocurable resin containing a light absorbing material as a base film, and has a plurality of mortar-shaped recesses from one main surface of the base film to the other main surface on the opposite side. The formed optical control filter has been proposed. In the light control filter, the recess is usually a light transmitting portion, and the other portion is a light blocking portion. Further, as a method for manufacturing an optical control filter, a method of pouring a curable resin into a molding mold provided with protrusions corresponding to recesses formed on the film surface, curing the mold, and removing the mold is disclosed. Further, as a molding substrate material, a resin or metal that can be machined is exemplified.

Japanese Unexamined Patent Publication No. 2017-54129

However, as a result of studies by the present inventors, it has been difficult to arrange the protrusions at a high density by the method of forming the protrusions on the molding substrate by machining. Therefore, the present inventors have diligently studied a method for producing an optical control film having a high density of through holes using a molding die in which fine protrusions are formed on a silicon substrate by a photolithography method. However, due to the brittleness of the silicon substrate, there is a problem that the molding die cracks when the optical control film cured in the molding die is removed, and the manufacturing yield is low.

An object of the present invention is to provide a method for manufacturing an optical control filter capable of improving a manufacturing yield even if the optical control filter has fine light transmitting portions arranged at a high density.

The present invention has the following configurations.
[1] Using a molding die provided with a circular substrate in a plan view and a plurality of protrusions rising from the surface of the substrate, a liquid resin is injected into the molding die so as to be in contact with the plurality of protrusions. After that, the liquid resin is cured to form an optical control filter having recesses or through holes corresponding to the plurality of protrusions, and the optical control filter is demolded. Method.
[2] The molding mold includes a base base material having a plurality of concave substrate arrangement portions formed on the surface thereof.
The substrate is arranged on the bottom surface of the substrate arrangement portion, and the substrate is arranged.
An optical control filter in which a liquid resin is injected into the substrate arrangement portion so as to be in contact with the plurality of protrusions of the substrate, and then the liquid resin is cured to form recesses or through holes corresponding to the plurality of protrusions. The method for manufacturing an optical control filter according to [1], which comprises forming the above and removing the optical control filter.
[3] The method for manufacturing an optical control filter according to [2], wherein the substrate arrangement portion of the base base material has a circular shape in a plan view.
[4] The production of the optical control filter according to any one of [1] to [3], which comprises inserting a blade along the plane direction of the demolded optical control filter to remove the residual film remaining on the back surface. Method.

According to the present invention, it is possible to provide a method for manufacturing an optical control filter that can improve the manufacturing yield even if the optical control filter has fine light transmitting portions arranged at high density.

It is a top view which showed the molding mold of 1st Embodiment. It is a cross-sectional view of AA of the molding die of FIG. It is sectional drawing which showed each process of the manufacturing method of the optical control filter of 1st Embodiment. It is sectional drawing which showed an example of the optical control filter manufactured by this invention. It is sectional drawing which showed the other example of the optical control filter manufactured by the invention. It is a top view which showed the molding die of 2nd Embodiment. FIG. 6 is a cross-sectional view taken along the line BB of the molding die of FIG. It is sectional drawing which showed the other example of the molding die used in this invention.

The method for manufacturing an optical control filter of the present invention uses a molding mold provided with a circular substrate in a plan view and a plurality of protrusions rising from the surface of the substrate, and a plurality of protrusions corresponding to the plurality of protrusions are used. This is a method for manufacturing an optical control filter in which a recess or a plurality of through holes are formed.

Hereinafter, a method for manufacturing an optical control filter will be described in detail while showing a specific example of the molding die to be used. It should be noted that the dimensions and the like of the figures illustrated in the following description are examples, and the present invention is not necessarily limited thereto, and the present invention can be appropriately modified without changing the gist thereof. ..

[First Embodiment]
(Molding mold)
FIG. 1 is a plan view of the molding die 100 used in the first embodiment. FIG. 2 is a cross-sectional view taken along the line AA of the molding die 100.
The molding die 100 includes a substrate 110 having a circular shape in a plan view, and a plurality of protrusions 120 rising from the surface of the substrate 110. In the molding die 100, a concave molding portion 112 having a circular shape in a plan view is formed on the surface side of the substrate 110, and a plurality of protrusions 120 are provided on the bottom surface 112a (surface) of the molding portion 112. ..

The plan view shape of the substrate 110 is circular, and the plan view shape of the concave molding portion 112 formed on the surface side of the substrate 110 is also circular.
The diameter of the substrate 110 in a plan view is appropriately set according to the size of the optical control filter to be manufactured.

The depth of the molded portion 112 is preferably 50 μm or more and 1000 μm or less, more preferably 80 μm or more and 500 μm or less, and further preferably 100 μm or more and 300 μm or less. By adjusting the depth of the molded portion 112, the thickness of the manufactured optical control filter can be adjusted.
The diameter of the molded portion 112 in a plan view is not particularly limited, and may be, for example, 5 mm or more and 100 mm or less.

The arrangement of the protrusions 120 on the bottom surface 112a of the molding unit 112 in a plan view is not particularly limited, and examples thereof include a zigzag arrangement and a random random arrangement.
The cross-sectional shape of the protrusion 120 perpendicular to the axial direction is not particularly limited, and examples thereof include a circular shape and an elliptical shape. Of these, a circular shape (perfect circle) is preferable from the viewpoint of avoiding mold breakage due to pressure distribution during molding.

The diameter of the protrusion 120 is preferably 2 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less, and further preferably 2 μm or more and 10 μm or less. When the diameter of the protrusion 120 is equal to or greater than the lower limit of the above range, the protrusion can be easily formed. When the diameter of the protrusion 120 is not more than the upper limit of the above range, it is easy to manufacture an optical control filter having a recess or a through hole having a high aspect ratio.
The diameter of the protrusion 120 is the diameter of the protrusion 120 at a position corresponding to the bottom surface 112a of the molded portion 112. When the cross-sectional shape perpendicular to the axial direction of the protrusion 120 is not circular, the diameter of the protrusion 120 is the diameter of the circumscribed circle of the cross section of the protrusion 120.

The height of the protrusion 120, that is, the distance from the bottom surface 112a of the molded portion 112 to the tip of the protrusion 120 is preferably 50 μm or more and 1000 μm or less, more preferably 80 μm or more and 500 μm or less, and further preferably 100 μm or more and 300 μm or less. When the height of the protrusion 120 is equal to or greater than the lower limit of the above range, the optical control filter can be easily manufactured. When the height of the protrusion 120 is equal to or less than the upper limit of the above range, the protrusion 120 is likely to be held during manufacturing, especially during demolding.

In this example, the position of the tip of the protrusion 120 is flush with the surface of the portion of the substrate 110 other than the molded portion 112. That is, the position of the tip of the protrusion 120 coincides with the position of the open end of the molding portion 112. When the molding die 100 of this aspect is used, as will be described later, it is possible to manufacture an optical control filter in which a plurality of through holes corresponding to the protrusions 120 are formed.
When the position of the tip of the protrusion 120 is lower than the surface of the portion of the substrate 110 other than the molded portion 112, that is, when the position of the tip of the protrusion 120 is lower than the position of the open end of the molded portion 112, An optical control filter having a plurality of recesses corresponding to the protrusions 120 can be manufactured.

The clearance between the protrusions 120 is more preferably 2 μm or more and 20 μm or less, particularly preferably 2 μm or more and 15 μm or less, and most preferably 2 μm or more and 10 μm or less. When the clearance between the protrusions 120 is equal to or greater than the lower limit of the above range, the molding die 100 can be easily manufactured. When the clearance between the protrusions 120 is equal to or less than the upper limit of the above range, it is easy to manufacture an optical control filter in which fine light transmitting portions are arranged at high density.
The clearance between the protrusions 120 is the shortest distance between the side surfaces of the protrusions 120 on a plane that coincides with the bottom surface 112a of the molding portion 112.

^{The number of protrusions 120 per 100 μm 2 on} the surface of the substrate 110 is preferably 4 or more and 100 or less, more preferably 8 or more and 70 or less, and further preferably 16 or more and 45 or less. When the number of the protrusions 120 is equal to or greater than the lower limit of the range, it is easy to manufacture an optical control filter in which fine light transmitting portions are arranged at high density. When the number of the protrusions 120 is equal to or less than the upper limit of the above range, the molding die 100 can be easily manufactured.

The plurality of protrusions 120 are preferably along the perpendicular direction of the substrate 110 in terms of ease of manufacturing and ease of viewing angle control.

The protrusion 120 can be formed by, for example, machining.
The material for forming the substrate 110 and the protrusion 120 may be any material that has heat resistance and can be prevented from being easily deformed or damaged. For example, a resin such as acrylic resin, aluminum, copper, or the like is used. Examples thereof include inorganic compounds such as metals and ceramics. The material forming the substrate 110 and the protrusion 120 may be one type or two or more types.

A metal wire may be inserted into the metal wire insertion recess formed in the substrate 110 to form the protrusion 120, or a metal wire may be inserted into the metal wire insertion hole formed in the substrate 110 to form the protrusion 120. Examples of the metal forming the metal wire include tungsten, titanium, and nickel.

The method for producing the molding die 100 is not particularly limited. For example, a method of dry etching one surface of the substrate 110 and a method of cutting one surface of the substrate 110 can be exemplified. Examples of dry etching include plasma etching, laser etching, and ion etching. As a method of plasma etching, a method of arranging a mask on the surface of a substrate, irradiating the surface of the substrate with plasma through the mask, and etching only the surface not covered with the mask can be exemplified.

(Manufacturing method of optical control filter)
Hereinafter, a method for manufacturing an optical control filter using the molding die 100 will be described. As a method for manufacturing the optical control filter of the first embodiment, for example, the following method can be exemplified.
First, as shown in FIG. 3A, the liquid resin L is injected into the molding portion 112 of the molding mold 100 so as to be in contact with the plurality of protrusions 120. Next, as shown in FIG. 3B, the liquid resin L is cured to form an optical control filter 10 in which a plurality of through holes 12 corresponding to the plurality of protrusions 120 are formed. Next, as shown in FIG. 3C, the light control filter 10 is removed from the mold 100.

The method of injecting the liquid resin L into the molding portion 112 of the molding die 100 and curing it is not particularly limited, and examples thereof include the following methods (a-1) to (a-4).
(A-1): The liquid resin L is applied onto the flat surface of the support film to form a film of the liquid resin L, and then the molding portion 112 of the molding die 100 is pressed against the film to cure the liquid resin L. How to make it.
(A-2): A method in which a liquid resin L is poured into a molding portion 112 of a molding mold 100, filled in the molding portion 112 using a spatula or the like, and then the liquid resin L is cured.
(A-3): The liquid resin L is applied to the molding portion 112 of the molding mold 100, the applied liquid resin L is pressed by a pressing die, the liquid resin L is filled in the molding portion 112, and then the liquid resin L is applied. How to cure.
(A-4): A method in which a molding die 100 is attached to an injection molding machine and a liquid resin L is injection molded into a molding portion 112.

As the support film used in the method (a-1), a film that can be easily peeled off from the obtained light control filter 10 is preferable, and examples thereof include a polyethylene terephthalate film and a polypropylene film.
As a method of applying the liquid resin L to the support film, a method using a known coater can be exemplified.

The method for applying the liquid resin L in the method (a-3) may be the method exemplified by the method (a-1), and the liquid adhered to an arbitrary position of the molding portion 112 of the molding die 100. A method may be used in which a pressing die is pressed against the resin L to spread the liquid resin L.
In the method (a-4), a known injection molding machine can be used.

The amount of the liquid resin L used when injecting into the molding portion 112 of the molding die 100 is adjusted to a sufficient amount for producing the target optical control filter 10.
When the liquid resin L is injected into the molding portion 112 of the molding mold 100, as shown in FIG. 3A, even if a part of the liquid resin L overflows to the outside of the molding portion 112 on the substrate 110. Good. In this case, as shown in FIG. 3B, the liquid resin L overflowing to the outside of the molded portion 112 becomes the residual film 20 remaining on the back surface of the light control filter 10 after curing. However, the excess residual film 20 can be removed before or after demolding.

As a method for removing the residual film 20, for example, a contact type method for cutting or polishing the surface of a general substrate, a non-contact type method such as laser processing or plasma processing can be exemplified. As a method for removing the residual film 20, a method of removing the residual film 20 by inserting a blade along the plane direction of the demolded optical control filter is preferable.
Forming the residual film 20 is advantageous in that when the liquid resin L is cured, the shape of the edge of the opening of the molding portion 112 and the shape of the tip of the protrusion 120 are easily reflected in the formed optical control filter 10. Is.

The method for curing the liquid resin L may be appropriately selected according to the type of the liquid resin L.
When the liquid resin L is thermosetting, for example, a method of heating the molding die 100 and a method of heating using an external heater provided separately from the molding die 100 can be exemplified. When the liquid resin L is photocurable, for example, a method of irradiating with ultraviolet rays or electron beams can be exemplified.

Examples of the liquid resin L include curable resins such as curable silicones, isocyanates, and polyols. The liquid resin L used may be one type or two or more types. A polymerization catalyst may be added to the liquid resin L. When the liquid resin L is thermosetting, a thermal polymerization catalyst is added, and when the liquid resin L is photopolymerizable, a photopolymerization catalyst is used.
If necessary, the liquid resin L may be further mixed with other components such as a solvent.

The liquid resin L preferably contains an elastomer.
Examples of the elastomer include thermoplastic elastomers such as urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, styrene butadiene rubber, and silicone rubber; urethane-based, ester-based, styrene-based, olefin-based, and butadiene. Thermoplastic elastomers such as system or fluorine-based; or composites thereof can be exemplified. Among these, silicone rubber is preferable because the dimensional change of the optical control filter after demolding from the molding die 100 is small, warpage does not occur after demolding, compression set is small, and heat resistance is high.
The elastomer is preferably a polymer having a shore hardness A of 80 or less as measured using a durometer according to JIS K6253.

The content of the elastomer in the liquid resin L is preferably 70% by mass or more and 99.9% by mass or less, more preferably 80% by mass or more and 99.5% by mass or less, and 90% by mass, based on the total mass of the liquid resin L. % Or more and 99% by mass or less are more preferable. When the content is equal to or higher than the lower limit of the above range, the flexibility of the optical control filter is improved. When the content is not more than the upper limit of the above range, there is room for sufficiently containing other components such as a light-shielding material.

Since the optical control filter 10 containing the elastomer is flexible and elastically deformed, it is relatively easy to remove the optical control filter 10 from the molding die 100, and the substrate 110 of the molding die 100 is removed at the time of removal. It is easy to prevent the protrusion 120 from being damaged.

As shown in FIG. 3C, the demolded optical control filter 10 has a first main surface (front surface) 1 and a second main surface (back surface) 2 opposite to the first main surface 1. Has. In the molding die 100, the axial direction of the protrusion 120 and the side surface of the protrusion 120 are arranged perpendicular to the bottom surface 112a of the molding portion 112. Therefore, the inner surface of the through hole 12 in the obtained optical control filter 10 is formed perpendicular to the first main surface 1 and the second main surface 2 of the optical control filter 10.
The distance (pitch) between the through holes 12 coincides with the distance (pitch) between the protrusions 120. The inner diameter of the through hole 12 coincides with the diameter of the protrusion 120.

When the liquid resin L containing the light-shielding material is used, the portion of the through hole 12 becomes the light transmitting portion 3, and the other portion becomes the light-shielding portion 4. As shown in FIG. 4 (A), if necessary, the light control filter 10A may be formed by filling the portion of the through hole 12 with a light transmitting material to form the light transmitting portion 3. Further, as shown in FIG. 4B, a liquid resin L containing no light-shielding material is injected into the molding portion 112, cured and demolded, and then the through hole 12 is filled with the resin containing the light-shielding material. In addition, the portion of the through hole 12 may be the light-shielding portion 5, and the other portion may be the light control filter 10B which is the light-transmitting portion 6.

Examples of the light-transmitting material include transparent resin and glass. A transparent elastomer is preferable from the viewpoint of increasing the flexibility of the light control filter 10. Specific examples of the transparent elastomer include silicone and polyurethane. The transparent elastomer filled in the through hole 12 may be one type or two or more types. Silicone rubber is preferable as the transparent elastomer from the viewpoint of excellent transparency and heat resistance.

As the light-shielding material, at least one of a light-absorbing material and a light-reflecting material is used.
The light-absorbing material contains a light-absorbing agent. Examples of the light absorber include carbon, dyes, and pigments. Among the light absorbers, carbon is preferable because it has excellent light absorption. Examples of carbon include carbon black, graphite, and carbon fiber, and carbon black is preferable because it is versatile as a light absorber.
Examples of the light-reflecting material include metals such as aluminum, silver, gold, chromium, and nickel.

The method of filling the through hole 12 with the light-transmitting material or the light-shielding material is not particularly limited, and examples thereof include the following methods (b-1) to (b-3).
(B-1): A method in which a paint containing a light-transmitting material or a light-shielding material is poured onto the first main surface 1 of the light control filter 10 and is scraped into the through hole 12 using a spatula or the like to fill the first main surface 1.
(B-2): A method in which a paint containing a light-transmitting material or a light-shielding material is adhered to the first main surface 1 of the light control filter 10, and a stamping die is pressed against the paint to push it into the through hole 12 to fill the paint.
(B-3): A method of immersing the light control filter 10 in a paint containing a light-transmitting material or a light-shielding material to allow the paint to flow into the through holes 12.
The paint filled in the through hole 12 is cured by a conventional method.

The paint preferably contains a curable resin or a binder. Specific examples thereof include thermosetting silicones, isocyanates and polyols forming polyurethanes, acrylic compounds, epoxy compounds, and unsaturated polyesters.
A resin or glass optical fiber fitted in the through hole 12 of the optical control filter 10 may be inserted into the through hole 12.

The thickness of the light control filter 10 to be manufactured is preferably 50 μm or more and 1000 μm or less, more preferably 80 μm or more and 500 μm or less, and further preferably 100 μm or more and 300 μm or less. When the thickness of the optical control filter 10 is equal to or greater than the lower limit of the above range, it becomes easier to control the viewing angle of light. When the thickness of the optical control filter 10 is equal to or less than the upper limit of the above range, the flexibility becomes higher.
The thickness of the optical control filter 10 is determined as an average value of values measured at 10 or more randomly selected cross sections. A known microstructure observation means such as a measuring microscope is applied to the measurement.

The ratio of the total area of the portion other than the through hole 12 to the total area of the first main surface 1 or the second main surface 2 of the optical control filter 10 is preferably 36% or more and 99.2% or less, and 49% or more and 96. % Or less is more preferable, and 65% or more and 91 or less% is further preferable. The total area of the first main surface 1 and the total area of the portion other than the through hole 12 can be obtained by image processing the image obtained by photographing the main surface by a known method.
The ratio can be adjusted by adjusting the ratio of the protrusion 120 to the bottom surface 112a of the molding portion 112.

The light transmittance of the light transmitting portion is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more.
The light transmittance of the light-shielding portion is preferably less than 70%, more preferably less than 50%, further preferably less than 30%, and particularly preferably less than 10%.
Here, the value of "light transmittance" is set _{on the optical path of the inspection light in a device that uses D 65} specified in JIS Z 8720 as a light source and measures the intensity of the inspection light emitted from the light source with a light receiving sensor. The output value of the light receiving sensor when there is no object to be measured is A, the output value when the object to be measured is set on the optical path of the inspection light, and the transmitted light transmitted through the object to be measured is received by the light receiving sensor. Let B be a value obtained by light transmittance = (B / A) × 100 (unit:%).

Further, the first transparent sealing layer 8 and the second transparent sealing layer 9 are further laminated on each of the first main surface 1 and the second main surface 2 of the optical control filters 10A and 10B, and FIG. The optical control filters 20A and 20B illustrated in (A) and FIG. 5 (B) may be used.

The method for forming the first transparent sealing layer 8 and the second transparent sealing layer 9 on the first main surface 1 and the second main surface 2 is not particularly limited, and the transparent layer is formed on the surface of the substrate. The general method of doing so can be applied. Specifically, for example, the following methods (c-1) to (c-2) can be exemplified.
(C-1): A method of applying a coating material containing a thermosetting compound or a photocurable compound to the first main surface 1 and the second main surface 2 and heating or irradiating with light to cure the paint.
(C-2): A method of laminating a transparent resin film or transparent glass prepared in advance on the first main surface 1 and the second main surface 2.

Examples of the thermosetting compound and the photocurable compound include acrylic compounds, epoxy compounds, thermosetting silicones, isocyanates and polyols forming polyurethanes. The coating material containing these curable compounds may contain a polymerization initiator. Examples of the polymerization initiator include organic peroxides and azo compounds. The paint may contain a known organic solvent.

Examples of the method of laminating the transparent resin film or transparent glass include a method of bonding with an adhesive and a method of thermocompression bonding.

In the conventional molding die, since the concave molded portion is formed on the rectangular substrate, the stress generated during molding is concentrated on the straight portion of the molded portion, and damage is likely to occur. Further, when the optical control filter (molded product) is removed from the molding die, if the die is removed from the straight portion, the force applied to the protrusion during the removal from the mold increases, and the protrusion may break. Furthermore, when removing the residual film of the optical control filter before demolding, if the blade is inserted horizontally from the corner, the cutting width changes significantly, and the rate of change in stress generated during cutting increases, making it an optical control filter. Streaks are likely to occur.

On the other hand, in the molding die 100, since the molding portion 112 is formed on the substrate 110 having a circular plan view shape, it is difficult for the stress generated during molding to concentrate on a specific portion of the molding portion, and the molding die 100 has. Hard to break. Further, since the force applied to the protrusion 120 when the optical control filter 10 is removed from the mold is not excessively large, the protrusion 120 is prevented from breaking. Further, even if the residual film 20 of the optical control filter 10 before demolding is removed, the change in the cutting width is smaller and the rate of change in the stress generated at the time of cutting is smaller, so that the optical control filter is less likely to have streak spots. ..

[Second Embodiment]
(Molding mold)
FIG. 6 is a plan view of the molding die 200 used in the second embodiment. FIG. 7 is a cross-sectional view taken along the line BB of the molding die 200. In FIGS. 6 and 7, the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

The molding die 200 includes a base base material 210, a plurality of substrates 110, and a plurality of protrusions 120 rising from the surface of each substrate 110. In the molding die 200, a plurality of concave substrate arranging portions 212 are formed on the surface side of the base base material 210. Each of the plurality of substrates 110 is fitted into each concave substrate arranging portion 212 and arranged on the bottom surface 212a of the substrate arranging portion 212.

The plan view shape of the base base material 210 is circular in this example. The plan view shape of the base base material 210 is not limited to a circle, and may be an ellipse, a rectangle, a polygon of a pentagon or more, and the like.
The size of the base base material 210 is appropriately set according to the size and number of the optical control filters to be manufactured.

The number of substrate arranging portions 212 formed on the base base material 210 can be appropriately set, and can be, for example, 2 or more and 25 or less.
The plan view shape of the substrate arrangement portion 212 is preferably a circle that is the same as the plan view shape of the substrate 110. The diameter of the substrate arrangement portion 212 in a plan view is appropriately set according to the diameter of the substrate 110 in a plan view. The plan view shape of the substrate arrangement portion 212 is not limited to a circle, and may be an ellipse, a rectangle, a polygon of a pentagon or more, and the like.

The depth of the board arrangement portion 212 can be appropriately set. The depth of the substrate arrangement portion 212 may be constant with the thickness of the substrate 110, may be larger than the thickness of the substrate 110, or may be smaller than the thickness of the substrate 110.

The method for producing the base base material 210 is not particularly limited, and examples thereof include cutting and etching. Specifically, the same method as that described in the method for producing the molding die 100 can be mentioned.

(Manufacturing method of optical control filter)
Hereinafter, a method for manufacturing an optical control filter using the molding die 200 will be described. As a method for manufacturing the optical control filter of the second embodiment, the same method as that of the first embodiment can be adopted except that the molding die 200 is used instead of the molding die 100.
Specifically, the liquid resin L is injected into each of the substrate arranging portions 212 of the molding die 200 so as to be in contact with the plurality of protrusions 120. Next, the liquid resin L is cured to form an optical control filter in which a plurality of through holes corresponding to the plurality of protrusions 120 are formed. Next, the light control filter is removed from the mold 200.

In the case of using the molding die 200 as well as in the case of using the molding die 100, when the liquid resin L is injected into the substrate arranging portion 212, a part of the liquid resin L overflows to the outside of the molding portion 112 in the substrate 110. You may do so. The residual film 20 covering one main surface of the cured optical control filter can be removed by cutting or polishing.

In the method using the molding die 200, light is formed except that a plurality of through holes corresponding to the protrusions 120 are formed, which are reduced in diameter from the second main surface 2 side to the first main surface 1 side. An optical control filter having the same aspect as the control filter 10 can be obtained. The distance (pitch) between the through holes coincides with the distance (pitch) between the protrusions 120. The inner diameter of the through hole coincides with the diameter of the protrusion 120.
Thickness of the light control filter, ratio of the total area of the portion other than the through hole to the total area of the first main surface 1 or the second main surface 2, the light transmittance of the light transmitting portion, the light transmittance of the light transmitting portion, etc. The preferred embodiment of the above is the same as the preferred embodiment of the optical control filter 10.

When the liquid resin L containing the light-shielding material is used, the portion of the through hole becomes the light transmitting portion 3, and the other portion becomes the light-shielding portion 4. Further, as in the case of the light control filter 10, in the light control filter, a light transmitting material may be filled in the through hole portion to form the light transmitting portion 3, if necessary. Further, the liquid resin L containing no light-shielding material is injected into the substrate arrangement portion 212, cured and demolded, and then the through hole is filled with the resin containing the light-shielding material so that the through-hole portion becomes the light-shielding portion. There may be an optical control filter in which the other portion is a light transmitting portion.
Further, the first transparent sealing layer and the second transparent sealing layer may be further laminated on each of the first main surface 1 and the second main surface 2 of the optical control filter.

Even when the molding die 200 is used, the stress generated during molding is unlikely to be concentrated on a specific portion of the molding portion, and the molding die 200 is unlikely to be damaged. Further, since the force applied to the protrusion 120 when the optical control filter is removed from the mold 200 does not become too large, the protrusion 120 is prevented from breaking. Further, even if the residual film of the optical control filter before demolding is removed, the change in the cutting width is smaller and the rate of change in the stress generated at the time of cutting is smaller, so that the optical control filter is less likely to have streak spots.
Further, when the molding die 200 is used, even if the substrate 110 and the protrusion 120 are damaged, only the damaged substrate 110 and the protrusion 120 can be removed from the substrate arrangement portion 212 and replaced.

The optical control filter manufactured by the present invention is attached to an image display device such as a liquid crystal display device for the purpose of controlling the viewing angle, improving the brightness, preventing glare, and the like. Specifically, the optical control filter can be attached to, for example, a light emitting diode, a light emitting body such as an organic electroluminescence element, or a light receiving body such as an optical sensor.

As described above, in the present invention, a plurality of recesses or a plurality of recesses corresponding to the plurality of protrusions are used by using a molding mold in which a plurality of protrusions are provided so as to rise from the surface of the circular substrate in a plan view. An optical control filter having through holes is formed. By using such a molding die, the manufacturing yield can be improved even in an optical control filter in which fine light transmitting portions are arranged at a high density.

The present invention is not limited to the method using the above-mentioned molding dies 100 and 200.
For example, in the molding dies 100 and 200 shown in FIGS. 8A and 8B, the molding dies 100A and 200A in which the position of the tip of the protrusion 120 is lower than the position of the opening end of the molding portion 112 are used. A method may include forming an optical control filter in which a plurality of recesses corresponding to the protrusions 120 are formed and removing the mold.
The method for manufacturing the optical control filter of the present invention may be a method using a molding die in which a plurality of concave molding portions are formed on a circular substrate in one plan view.

1 ... 1st main surface, 2 ... 2nd main surface, 3, 6 ... light transmitting portion, 4, 5 ... shading portion, 8 ... first transparent sealing layer, 9 ... second transparent sealing layer 10, 10 ... Optical control filter, 12 ... Through hole, 100, 100A, 200, 200A ... Molding mold, 110 ... Substrate, 112 ... Molding part, 112a ... Bottom surface, 120 ... Protrusion part, 210 ... Base base material, 212 ... Substrate Arrangement part, 212a ... Bottom surface.

Claims (4)

Using a molding die provided with a circular substrate in a plan view and a plurality of protrusions rising from the surface of the substrate, a liquid resin is injected into the molding die so as to be in contact with the plurality of protrusions. A method for manufacturing an optical control filter, which comprises curing the liquid resin to form an optical control filter having recesses or through holes corresponding to the plurality of protrusions, and demolding the optical control filter. The molding mold includes a base base material having a plurality of concave substrate arrangement portions formed on the surface thereof.
The substrate is arranged on the bottom surface of the substrate arrangement portion, and the substrate is arranged.
An optical control filter in which a liquid resin is injected into the substrate arrangement portion so as to be in contact with the plurality of protrusions of the substrate, and then the liquid resin is cured to form recesses or through holes corresponding to the plurality of protrusions. The method for manufacturing an optical control filter according to claim 1, which comprises forming the above and removing the optical control filter. The method for manufacturing an optical control filter according to claim 2, wherein the substrate arrangement portion of the base base material has a circular shape in a plan view. The method for manufacturing an optical control filter according to any one of claims 1 to 3, wherein a blade is inserted along the plane direction of the demolded optical control filter to remove a residual film remaining on the back surface.

Images