JP2004042475A - Manufacturing method of roll stamper for micro lens array sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a roll stamper by which the roll stamper for molding a micro lens array sheet can highly precisely and easily be manufactured, and also, the micro lens array sheet which is manufactured by using the roll stamper, is inexpensive, and has a large area, and of which the surface precision is good. <P>SOLUTION: A sheet-form original plate of a comparatively small area having an engraved surface corresponding to an element pattern of the micro lens array is prepared.The sheet-form original plate is pushed into a cylinder for a transfer roll, and a transfer-engraving is performed.Thus, a multiple imposition and rolling of the engraved surface are performed in a first process.A process wherein the transfer roll is further pushed into another cylinder for transferring, and transfer-engraving is performed is repeated a plurality of times to prepare an original plate roll in a second process.Reverse molds by embossing of the lens array pattern on the surface of the original plate roll are connected and imposed in a third process.This manufacturing method for the roll stamper is equipped with those three processes.Such a manufacturing method for the roll stamper is adopted. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a microlens array sheet and a method for manufacturing the same.
[0002]
[Prior art]
As a lens sheet used in a transmission screen or the like, a so-called microlens array sheet in which substantially hemispherical unit lenses are two-dimensionally arranged has been proposed.
[0003]
Such a microlens array sheet is generally formed by a mold having an emboss reverse mold corresponding to the outer shape. In such a mold, a method of engraving the surface of the mold member, a method of applying a photosensitive resin as a photoresist to the surface of the mold member, and applying a photoresist through a glass mask on which an embossed pattern is drawn is applied. It is manufactured by a so-called photoetching method in which only the light-irradiated portion is cured by irradiating the film, and the mold member is immersed in a developing solution to expose the cured portion to a required pattern.
[0004]
However, the above-described conventional methods for manufacturing a mold are all for producing a mold member (flat stamper) for sheet-fed molding.
[0005]
Japanese Patent Application Laid-Open No. 2001-30273 proposes a method for producing a roll mold for continuous molding. According to this method, a unit lens is directly formed on a cylindrical surface serving as a roll stamper having a large area by laser light or the like.
For this reason, although there is an advantage that a roll stamper can be directly manufactured, it is necessary to form a uniform and high-precision pattern over a large area, so that the processing difficulty is extremely high, and as a result, It is difficult to produce a highly accurate and inexpensive lens sheet.
[0006]
[Problems to be solved by the invention]
In view of the above, an object of the present invention is to provide an easy and inexpensive method for manufacturing a microlens array sheet forming roll stamper, and to easily manufacture a high-precision, large-area microlens array sheet manufactured using the same. It is to provide a manufacturing method which can be performed.
[0007]
[Means for Solving the Problems]
According to the present invention, an uneven surface (forward or reverse) corresponding to an element pattern of a lens array in which substantially hemispherical unit lenses are two-dimensionally arrayed at a pitch of 100 μm or less on a plane smaller than the area of the microlens array sheet to be manufactured. ) To prepare a relatively small flat plate
By rolling the first transfer roll cylinder, whose circumferential area is substantially equal to the uneven surface of the plate-shaped original plate, while pushing the cylinder into the plate-shaped original plate, the reverse shape (reverse or normal) of the uneven surface is circumferentially formed. Producing a first transfer roll transferred and formed on the surface;
Preparing a cylinder for a second transfer roll having a larger circumferential area than the first transfer roll,
By rolling the first transfer roll and the cylinder for the second transfer roll while pressing them relatively, the uneven surface (reverse or normal) formed on the circumferential surface of the first transfer roll is obtained. The step of transferring and forming the reverse shape (forward or reverse) on the circumferential surface of the second transfer roll cylinder is repeated at least once or more, so that the reverse shape (forward or reverse) of the uneven surface (reverse or front) is formed on the surface. A step of producing an original roll to be attached;
Finally, a third transfer roll cylinder which is to be a roll stamper is prepared, and the third transfer roll cylinder and the original roll are rolled while relatively pushing them in, whereby the circumference of the original roll is rotated. Forming a reverse shape (reverse) of the uneven surface (normal) formed on the surface on the circumferential surface of the third transfer roll cylinder;
And a method for producing a roll stamper.
[0008]
In the above description, “the area of the circumferential portion is large” means that the circumference of the circumference is large (that is, the diameter is large) and / or the length in the direction perpendicular to the circumference (that is, the length of the cylinder is large). At least one of the following).
[0009]
In the case where the concave and convex surface formed on the plate-shaped original plate as a starting point is the reverse type of the concave and convex surface of the pattern of the microlens array to be finally manufactured, the second transfer roll cylinder The original roll formed by using the above becomes a roll stamper.
[0010]
In the present invention, since starting from a plate-shaped master having a sculptured surface corresponding to a highly-accurate microlens array having a relatively small area obtained by known photo-etching or the like, the high-precision unevenness of the master is roll-stamped. , A highly accurate lens sheet is formed even in a large area.
When a microlens array sheet is applied to a transmission screen, in order to obtain a large-sized lens sheet of 30 inches square or more, when manufacturing a molding stamper of a size corresponding to the large-sized lens sheet, a fine unit over a large size Forming a reverse mold of a lens with high precision is an operation requiring enormous time, labor and cost.
[0011]
In the present invention, since the starting point is an original having a smaller size than the lens sheet to be manufactured, time, labor and cost can be reduced. However, as a highly accurate original, a size of 6 inch square or less is preferable. is there.
[0012]
Of the precision required for the master, the surface roughness is desirably about 2.5 μm, and in the case of the master having a surface roughness of 2.5 μm or less and a good smoothness, the smoothness is faithfully reflected on the lens sheet. be able to.
[0013]
The original plate is prepared, and the plate-shaped original plate is pressed into a cylinder for an original plate roll and engraved. By performing multiple imposition and rolling of the plate-shaped original plate, an original plate roll is produced. A high-precision roll stamper can be easily manufactured by indenting and engraving the cylinder for use. Therefore, a large-area microlens array sheet can be manufactured at low cost.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 is a diagram for explaining an embodiment of the present invention.
First, a flat original plate 1 having an engraved surface corresponding to an element pattern of a lens array in which substantially hemispherical unit lenses each having a lens diameter of 100 μm or less are two-dimensionally arranged on a plane having a size of 6 inches square or less is prepared. .
[0016]
As a manufacturing method of the plate-shaped original plate 1, a mechanical cutting method using a cutting tool having an arbitrary curved shape, a photo-etching method, or the like can be used.
The smaller the plate-shaped original plate 1 is, the easier it is to mold with high precision.
[0017]
In consideration of use as a transmission screen, a fine pitch is also desired for a lens sheet constituting the screen in order to provide a high-resolution image quality. For this reason, the lens array pattern engraved on the flat original plate preferably has a unit lens arrangement pitch of 100 μm or less.
The engraved surface of the lens array pattern is desired to have high surface accuracy, and the surface roughness is preferably 2.5 μm or less.
[0018]
The material of the plate-shaped original plate is not particularly limited, and may be any material having a hardness that enables the plate-shaped original plate to be pressed into the cylinder for the original plate roll and engraved. Metals having a Shore hardness of 70 ° or more, such as iron and nickel, are preferably used.
[0019]
Next, as shown in FIG. 1A, the plate-shaped original plate 1 is pressed into a first transfer roll cylinder 2 to perform engraving. In order to manufacture the first transfer roll 3 by pressing the engraved shape of the plate-shaped original 1 into the cylinder 2 for the first transfer roll, the first transfer roll cylinder 2 is rotated in contact with the plate-shaped original 1. While sending while shifting by several pitches per rotation.
[0020]
Next, as shown in FIG. 1 (b), the first transfer roll 3 is pressed into another second transfer roll cylinder 4, and the surface shape of the first transfer roll 3 is changed to the second transfer roll cylinder. After repeating the process of transferring and forming (transfer engraving) the cylinder 4 several times, the roll finally produced is the original roll.
Generally, the transfer step is repeated four or five times to remove unevenness.
In FIG. 1B, the first transfer roll 3 and the second transfer roll cylinder 4 are illustrated as having the same size, but the latter has a larger circumferential area than the former. Required.
[0021]
Further, it is possible to select whether the final engraving pattern on the roll stamper is a normal type or a reverse type with respect to the lens type of the original plate on the flat plate, depending on whether the number of repetitions of the above-described transfer step is even or odd.
For this reason, as the plate-shaped original plate 1, an original plate having an inverted (not a regular) emboss required for a roll stamper can be used.
[0022]
A flat plate is more effective than a roll in forming a highly accurate original pattern, but in the present invention, a roll original may be used instead of the flat original 1.
Naturally, the smaller the number of repetitions of the transfer step, the less the accuracy of the flat original plate 1 is reflected on the roll stamper and the manufactured lens sheet.
[0023]
Further, as shown in FIG. 2, the master roll 5 is pressed into an embossing roll cylinder 6 to perform engraving. To produce the roll stamper by pressing the engraved shape of the original roll 5 into the roll stamper cylinder 6 to produce a roll stamper, the roll stamper cylinder is fed while being shifted by several pitches per rotation while rotating in contact with the original roll.
The material of the roll stamper cylinder is not particularly limited, and any material generally used as a roll stamper cylinder can be used without any problem.
[0024]
In general, since the roll temperature at the time of forming greatly affects the formability, a structure having an appropriate temperature can be preferably used. A roll having an internal structure capable of easily adjusting the temperature with a heat medium such as water or oil is preferable.
[0025]
Hereinafter, a method of manufacturing a microlens array sheet by a method (2P method) using a radiation-curable resin using a roll stamper manufactured by the above method will be described.
[0026]
First, a translucent resin base material film coated with a radiation-curable resin by a coating device is nipped using a nip roll with respect to a roll stamper. Then, in a state where the surface of the translucent resin base film is in contact with the roll stamper, radiation is irradiated from the back side of the translucent resin base film to cure the radiation-curable resin, and the roll surface of the roll stamper is rolled. The lens array corresponding to the pattern is formed.
Through the above steps, a microlens sheet having a lens array element pattern in which substantially hemispherical unit lenses are two-dimensionally arranged at a pitch of 100 μm or less is manufactured.
[0027]
In the above-described embodiment, the microlens array is formed by a method using a radiation curable resin by using the roll stamper having the above configuration. However, the base film is continuously supplied, and the surface of the roll stamper is formed. Any existing technique can be used as long as the technique can continuously transfer the engraving. For example, a desired microlens array sheet is manufactured by embossing a thermoplastic resin or the like using the roll stamper having the above configuration.
[0028]
【The invention's effect】
As described above, according to the present invention, a flat original plate (or a roll-shaped original plate) having a small area and a high-precision engraved surface manufactured using a known method such as photoetching is used. By directly engraving the engraved shape of the original plate on the roll stamper via the original plate roll, it is possible to easily and inexpensively manufacture a roll stamper having a fine pitch between the lens portions and the lens portion and having high surface accuracy. A large-area microlens array sheet can be easily manufactured.
[0029]
[Brief description of the drawings]
FIGS. 1A and 1B are schematic views showing an embodiment of the present invention. FIG. 1A is a step of manufacturing a first transfer roll using a flat original plate, and FIG. 1B is a step of removing unevenness and an original roll. Explanatory drawing which shows the process of producing.
FIG. 2 is an explanatory view showing a step of manufacturing a roll stamper using an original roll.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Plate original 2 ... 1st transfer roll cylinder 3 ... 1st transfer roll 4 ... Transfer roll cylinder (original roll)
5: Original roll 6: Roll stamper cylinder

Claims (5)

A flat original plate having a concave-convex surface (positive) corresponding to an element pattern of a lens array in which substantially hemispherical unit lenses are two-dimensionally arranged at a pitch of 100 μm or less on a plane smaller than the area of the microlens array sheet to be manufactured. Prepare
Prepare a first transfer roll cylinder having an area of a circumferential portion substantially equal to the uneven surface of the plate-shaped original plate,
By rolling while pressing the first transfer roll cylinder into the flat plate precursor, a first transfer roll in which the reverse shape (reverse) of the uneven surface of the flat plate master is transferred and formed on the circumferential surface is produced. The process of
Preparing a cylinder for a second transfer roll having a larger circumferential area than the first transfer roll,
The first transfer roll and the second transfer roll cylinder are rolled while relatively pushing them in, so that the concave and convex surfaces (reverse) formed on the circumferential surface of the first transfer roll are inverted. The step of transferring (positive) to the circumferential surface of the cylinder for the second transfer roll is repeated at least once or more to produce an original roll in which the reverse shape (positive) of the uneven surface (reverse) is imposed. The process of
Finally, a third transfer roll cylinder which is to be a roll stamper is prepared, and the third transfer roll cylinder and the original roll are rolled while relatively pushing them in, whereby the circumference of the original roll is rotated. Forming a reverse shape (reverse) of the uneven surface (normal) formed on the surface on the circumferential surface of the third transfer roll cylinder;
And a method for manufacturing a roll stamper. A plane having a size smaller than the area of the microlens array sheet to be manufactured has an uneven surface (reverse) corresponding to the reverse shape of the element pattern of the lens array in which the substantially hemispherical unit lenses are two-dimensionally arranged at a pitch of 100 μm or less. Prepare a plate original,
Prepare a first transfer roll cylinder having an area of a circumferential portion substantially equal to the uneven surface of the plate-shaped original plate,
Producing a first transfer roll in which the reverse shape (positive) of the concavo-convex surface is transferred and formed on a circumferential surface by rolling while pressing the first transfer roll cylinder into the flat plate precursor;
A second transfer roll cylinder having a larger circumferential area than the first transfer roll and finally serving as a roll stamper is prepared,
By rolling the transfer roll and the cylinder for the second transfer roll while pressing both relatively, the reverse shape (reverse) of the uneven surface (positive) formed on the circumferential surface of the transfer roll is obtained. A step of producing a roll stamper obtained by imposing a reverse shape (reverse) of the irregular surface (positive) by repeating at least one or more times a step of forming a transfer on a circumferential surface of the second transfer roll cylinder;
And a method for manufacturing a roll stamper. An uneven surface corresponding to the shape (or inverse shape) of an element pattern of a lens array in which substantially hemispherical unit lenses are two-dimensionally arranged at a pitch of 100 μm or less on a plane smaller than the area of the microlens array sheet to be manufactured. As a plate-shaped master with
The method according to claim 1, wherein a surface roughness of the uneven surface is 2.5 μm or less. Element patterns of a lens array having a size of 6 inches square or less, in which substantially hemispherical unit lenses are two-dimensionally arranged at a pitch of 100 μm or less, are repeated so that boundaries between the element patterns are not noticeable, and are two-dimensionally arranged on the surface. A microlens array sheet, which is arranged. 4. A micro-mold having a surface roughness of 2.5 [mu] m or less, obtained by transfer-forming an inverse shape (positive) of a concavo-convex surface (reverse) on a molding surface of a roll stamper obtained by the manufacturing method according to claim 3. Lens array sheet.

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