JP4050881B2 - Optical element manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the production how of the optical element so as to collectively form an optical pattern on the substrate. The optical element targeted by the present invention may be anything as long as it has an optical pattern on both the front and back sides or one side. In particular, a CD (Compact Disc), a CD-R (Writable CD), a CD -ROM (read-only CD), LD (laser disc), MD (mini disc), DVD (digital versatile disc), DVD-ROM (read-only DVD), DVD-RAM (DVD that can be rewritten any number of times) An optical element used for an optical pickup that optically reads optical information recorded on an optical disc / magneto-optical disc such as) and generates a focus error signal and a tracking error signal is an object of the invention.
[0002]
[Prior art]
An optical element used as an optical pickup component for an optical disk is usually a few mm square, and a plurality of optical elements are collectively formed on a large transparent substrate for the purpose of mass production and low cost. It is manufactured by dividing after forming an optical pattern. In the optical element, a very fine pattern constituting a hologram or a diffraction grating (grating) is precisely formed. As a method for forming a fine pattern, a patent (Japanese Patent Application No. 11-055881) filed by the present inventor and applying the 2P (photopolymer) method is an effective means.
[0003]
Conventionally, as a method for manufacturing an optical element, there is a method performed as follows.
[0004]
First, as shown in FIG. 8A, an ultraviolet curable resin (2P resin) 102 is applied on a transparent lower stamper 112. Further, an ultraviolet curable resin 102 is applied on the rectangular plate-like transparent substrate 101, and the transparent substrate 101 is inserted between the lower stamper 112 and the upper stamper 111. A transfer front optical pattern is formed on the surface of the upper stamper 111 on the transparent substrate 101 side, and a transfer back optical pattern is formed on the surface of the lower stamper 112 on the transparent substrate 101 side.
[0005]
Next, as shown in FIG. 8 (b), the transparent substrate 101 is sandwiched between a transparent upper stamper 111 and a transparent lower stamper 112 and pressed, and an ultraviolet curable resin 102 is applied to the front and back surfaces of the transparent substrate 101. The ultraviolet curable resin 102 is cured by spreading and irradiating ultraviolet rays from above the upper stamper 111.
[0006]
Next, as shown in FIG. 8C, when the upper stamper 111 and the lower stamper 112 are released from the transparent substrate 101, a surface optical pattern of the upper stamper 111 is formed on the surface of the transparent substrate 101, and transparent A back optical pattern of the lower stamper 112 is formed on the back surface of the substrate 101.
[0007]
Next, in order to increase the number of entering the AR (anti-reflection) coating apparatus, the rectangular plate-like transparent substrate 101 is processed to form a disk-like transparent substrate 101a as shown in FIG. Then, as shown in FIG. 8E, AR coating is performed on the transparent substrate 101a.
[0008]
Finally, as shown in FIG. 8F, the transparent substrate 101a is diced using a dicing blade 201 to divide the transparent substrate 101a into a plurality of pieces. Thereby, as shown in FIG. 8G, individual optical elements are completed.
[0009]
In the optical element manufacturing method having the above-described configuration, the front and back optical patterns can be simultaneously formed on the ultraviolet curable resin 102 in close contact with the front and back surfaces of the transparent substrate 101, and a short production time and high production efficiency can be achieved.
[0010]
[Problems to be solved by the invention]
However, in the conventional method for manufacturing an optical element, when a glass substrate is used as the transparent substrate 101, a plurality of optical patterns are formed on a single glass substrate, and then divided into a predetermined shape by dicing. Although an optical element is produced, since it is diced using a diamond blade, there is a problem that it is expensive and time consuming.
[0011]
As a method for shortening the dicing time, there is a method using a plastic substrate as the transparent substrate 101. However, when a plastic substrate is used as the transparent substrate 101, it is possible to cut the plastic substrate at a higher speed than when a glass substrate is used. Burrs will occur.
[0012]
Therefore, an object of the present invention is to provide an optical element manufacturing method that can manufacture an optical element at low cost and can divide a substrate at high speed .
[0013]
[Means for Solving the Problems]
In the optical element according to the present invention, a primer layer is formed on both surfaces of a plastic substrate, and an ultraviolet curable resin layer having a fine pattern formed by the 2P method is formed on the primer layer.
[0014]
The method of manufacturing an optical element according to the present invention intends to increase the speed and cost of the dividing process by using a press to divide a plastic substrate on which a fine pattern is formed. In a state where the substrate is fixed so as not to occur, pressure is applied to the substrate by the upper and lower blades opposed to each other, and cracks are formed between elements of the substrate to separate the elements from each other.
[0015]
That is, in order to solve the above-described problem, the method for manufacturing an optical element of the present invention includes:
A step of holding a plastic substrate on which a plurality of optical elements are formed with a holder from around the plastic substrate;
Positioning the plastic substrate between the first and second blades facing each other;
Pressing the first and second blades against the plastic substrate and forming a crack between the plurality of optical elements;
And applying a force to the plastic substrate to separate the plurality of optical elements individually.
[0016]
According to the method for manufacturing an optical element having the above-described configuration, the first and second blades are pressed against a plastic substrate, cracks are formed between the plurality of optical elements, and then a force is applied to the plastic substrate. Separate the elements individually. Thus, since the plastic substrate is divided using the first and second blades, it can be manufactured at low cost and the plastic substrate can be divided at high speed.
[0017]
In addition, since a force is applied to the plastic substrate having cracks between the plurality of optical elements to separate the plurality of optical elements individually, burrs do not occur in the optical elements.
[0018]
In one embodiment of the method of manufacturing an optical element, the holder is thinner than the plastic substrate.
[0019]
According to the method for manufacturing an optical element of the above embodiment, when the first and second blades are pressed against the plastic substrate, the holder is thinner than the plastic substrate. Contact can be prevented.
[0020]
In one embodiment of the optical element manufacturing method, the holder is made of the same material as the plastic substrate and has the same thickness as the plastic substrate.
[0021]
According to the method for manufacturing an optical element of the above embodiment, the holder is made of the same material as the plastic substrate and has the same thickness as the plastic substrate, so that the processing of the peripheral portion of the plastic substrate and the central portion of the plastic substrate is performed. The conditions may be the same.
[0022]
An optical element manufacturing method according to an embodiment includes an entire surface of one surface of the plastic substrate between a step of cracking between the plurality of optical elements and a step of separating the plurality of optical elements individually. The process of sticking an adhesive sheet on is provided.
[0023]
According to the method of manufacturing an optical element of the above embodiment, since the adhesive sheet is attached to the entire surface of one surface of the plastic substrate, the plastic substrate is divided and a plurality of optical elements are separated individually. However, the optical element does not dissipate.
[0024]
In the optical element manufacturing method of one embodiment, the number of the first blades is plural, and the number of the second blades is plural.
[0025]
According to the method for manufacturing an optical element of the above embodiment, since the number of the first blades is plural and the number of the second blades is plural, it is possible to efficiently crack the plastic substrate.
[0026]
In the optical element manufacturing method of one embodiment, the first and second blades are formed in a lattice shape.
[0027]
According to the method of manufacturing an optical element of the above embodiment, since the first and second blades are formed in a lattice shape, the plastic substrate can be obtained by simply pressing the first and second blades against the plastic substrate once. It becomes a state that can be divided into a grid.
[0028]
In an optical element manufacturing method according to an embodiment, optical patterns are formed on both surfaces of the plastic substrate.
[0029]
In one embodiment of the method of manufacturing an optical element and the optical element, the optical element is a diffraction grating having a pitch of 20 μm or less.
[0030]
In one embodiment of the optical element manufacturing method, the plastic substrate is an acrylic resin.
[0031]
In the optical element manufacturing method according to one embodiment, the holder is annular.
[0032]
[0033]
[0034]
[0035]
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter will be described in detail by embodiments thereof illustrated in the manufacture how the optical element of the present invention.
[0037]
FIG. 1 is a view for explaining the principle of the optical element manufacturing method of the present invention. Reference numeral 1 in FIG. 1 is a plastic substrate on which a fine pattern as an optical pattern is formed.
[0038]
When the blades 2A and 2B, which are examples of the first and second blades, are pressed from both sides of the plastic substrate 1 and pressed, the crack 10 propagates when the blade edges of the blades 2A and 2B are slightly bitten into the plastic substrate 1. The plastic substrate 1 can be divided. However, if the blades of the blades 2A and 2B are slightly bitten into the plastic substrate 1, the plastic substrate 1 is only cracked 10, so that the shape of the plastic substrate 1 is kept as it is, and the plastic substrate 1 is divided. Requires a separate separation step. Further, it is desirable that the angle θ of the blade edges of the blades 2A and 2B is 60 degrees or less. Here, the angle θ of the cutting edges of the blades 2A and 2B is 26 degrees. Further, the pressure applied to the plastic substrate 1 by the blades 2A and 2B needs to be appropriately determined according to the strength of the workpiece and the length (time) of processing.
[0039]
FIG. 2 is an explanatory diagram for dividing, for example, one 3.2 mm square optical element from a plastic substrate on which hundreds of fine patterns are formed.
[0040]
First, a plastic substrate 21 is inserted into a mold in which linear blades 22A and 22B, which are examples of first and second blades shown in FIG. The board | substrate 21 will be in the state in which the division | segmentation of 1 line is possible.
[0041]
Next, as shown in FIG. 2B, after the upper and lower blades 22A and 22B are opened, step feed is performed at a pitch of 3.2 mm by a substrate feed mechanism (not shown).
[0042]
Next, as shown in FIG. 2C, by closing the upper and lower blades 22A and 22B again, the plastic substrate 21 is pressurized with the blades 22A and 22B, and the plastic substrate 21 can be divided into another line. It becomes a state.
[0043]
Then, by repeating the operations of FIGS. 2A to 2C, as shown in FIG. 2D, the plastic substrate 21 can be divided into a large number of lines.
[0044]
Thereafter, when the plastic substrate 21 is rotated 90 degrees with respect to the blades 22A and 22B and the operations shown in FIGS. 2A to 2C are repeated, the plastic substrate 21 includes a plurality of plastic substrates 21 as shown in FIG. It can be divided into pieces. Then, by performing a dividing step on the plastic substrate 21 in this state, it is possible to obtain 3.2 mm square optical elements separated individually.
[0045]
Hereinafter, an embodiment of a method for producing an optical element of the present invention will be described.
[0046]
First, a disk-shaped plastic substrate 31 on which several hundred fine patterns 30 shown in FIG. 3A are formed is formed into an annular holder 33 from the periphery of the plastic substrate 31 as shown in FIG. Hold on. Thereby, even if the plastic substrate 31 is divided, the plastic substrate 31 does not fall apart.
[0047]
Next, the operations of FIGS. 2A to 2C are repeated, so that the plastic substrate 31 can be divided along a plurality of dividing lines 34 in one direction as shown in FIG. 3C. . In the state shown in FIG. 2C, that is, when the upper and lower blades 22A and 22B are closed, the thickness of the holder 33 is set to a plastic substrate in order to bring the blades 22A and 22B into contact with only the plastic substrate 31. It is necessary to make it thinner than 31.
[0048]
Next, as shown in FIG. 3D, the plastic substrate 31 is rotated 90 degrees with respect to the blades 22A and 22B together with the holder 33. Then, the operations of FIGS. 2A to 2C are repeated so that the plastic substrate 31 can be divided along the plurality of dividing lines 34 in one direction. As a result, the plastic substrate 31 can be divided in two directions.
[0049]
Next, as shown in FIG. 3E, the adhesive sheet 35 is attached to the entire surface of one surface of the plastic substrate 31, and then the holder 33 is removed from the plastic substrate 31.
[0050]
Next, the plastic substrate 31 removed from the holder 33 is bent on a roller 36 as shown in FIG. Specifically, after the plastic substrate 31 is bent in one direction, the plastic substrate 31 is rotated 90 degrees with respect to the roller 36, and the plastic substrate 31 is bent in the other direction. Then, optical elements separated individually can be obtained. At this time, the adhesive sheet 35 holds the individual optical elements so that they do not fall apart. That is, the optical element is not dissipated by the adhesive sheet 35.
[0051]
Thereafter, as shown in FIG. 3G, the pressure-sensitive adhesive sheet 35 is expanded by an expander, and a gap is provided between the individual optical elements so that the subsequent process is easy to handle. Affix to ring 7. It is preferable to put the optical element in the assembly process in this state because a plurality of optical elements can be handled at one time.
[0052]
According to the method for manufacturing an optical element having the above configuration, the plastic substrate 31 is divided using the blades 22A and 22B. Therefore, the plastic substrate 31 can be manufactured at a low cost and can be divided at a high speed.
[0053]
Further, since the plastic substrate 31 having cracks between the plurality of optical elements is bent to separate the plurality of optical elements individually, no burr occurs in the optical elements.
[0054]
Further, since the dividing line 34 is set so as not to overlap the fine pattern 30, the plastic substrate 31 can be divided without affecting the fine pattern 30.
[0055]
In the above embodiment, the plastic substrate 31 is held from the periphery of the plastic substrate 31 by the annular holder 33, but may be held by a holder made of a plurality of rod-shaped members. Moreover, you may use a rectangular frame as a cyclic | annular holder.
[0056]
Further, as shown in FIGS. 4A to 4D, an optical element may be manufactured using a holder 43 instead of the holder 33.
[0057]
The holder 43 is a punched piece punched in the outer shape punching process when the disk-shaped plastic substrate 31 is manufactured. When this punched waste is reused to make the holder 43 of the plastic substrate 31, it is not necessary to create a special holder, so that further cost reduction can be realized.
[0058]
The holder 43 is made of the same material and the same thickness as the disc-shaped plastic substrate 31, so that it can be divided into a circular interior and a circular exterior simultaneously.
[0059]
Further, since the holder 43 is the same material and the same thickness as the disc-shaped plastic substrate 31, processing conditions are different when processing the peripheral portion of the plastic substrate 31 and when processing the central portion of the plastic substrate 31. There is no need to change.
[0060]
In the above embodiment, one blade 2A is pressed against one surface of the plastic substrate 31 and one blade 2B is pressed against the other surface of the plastic substrate 31. Alternatively, a plurality of blades may be pressed against the surface, and a plurality of blades may be pressed against the other surface of the plastic substrate 31. In short, the number of blades that are brought into pressure contact with the one or the other surface of the plastic substrate 31 may be plural.
[0061]
For example, as shown in FIG. 5B, three knives 52A as an example of a first blade are pressed against one surface of an acrylic substrate 51 made of acrylic resin as an example of a plastic substrate, and the acrylic substrate Three blades 52 </ b> B as an example of the second blade may be pressed against the other surface of 51.
[0062]
Hereinafter, an optical element manufacturing method using the blades 52A and 52B will be described.
[0063]
First, as shown in FIG. 5A, a plurality of blades 52A and 52B are set in parallel, and an acrylic substrate 51 on which several hundred fine patterns are formed is positioned between the blade 52A and the blade 52B. The interval between the blades 52A and 52B needs to be appropriately determined in consideration of the substrate size, the length of the cut line, the applied pressure, the strength of the workpiece, and the like. Here, the substrate size is set to a diameter of 116 mm, the cut line length is set to 116 mm, and the pressing force is set to 5 tons. The interval between the blades 52A and 52B is set to 3.2 mm.
[0064]
Next, as shown in FIG. 5B, once the blades 52 </ b> A and 52 </ b> B are brought into pressure contact with the respective surfaces of the acrylic substrate 51, the acrylic substrate 51 can be divided into three lines.
[0065]
Then, by feeding 9.6 mm step by a feeding mechanism (not shown), divided lines are formed in order of 3 lines. Here, when step feeding is performed 13 times, the machining in one direction is completed as shown in FIG.
[0066]
Thereafter, when the acrylic substrate 51 is rotated by 90 degrees with respect to the blades 52A and 52B and the same operation as that shown in FIGS. 5B and 5C is performed, the acrylic substrate 51 becomes as shown in FIG. It becomes a state that can be divided in two directions. Thereafter, by performing the same steps as those in FIGS. 3E and 3F, a 3.2 mm square optical element can be obtained.
[0067]
Also, as shown in FIGS. 6A and 6B, a lattice-shaped blade 62A, which is an example of a first blade, is brought into pressure contact with one surface of the plastic substrate 21, and the other surface of the plastic substrate 21 is contacted. You may press-contact the grid-shaped blade 62B which is an example of a 2nd blade. Thus, since the blades 62A and 62B facing each other are in a lattice shape, a vertical division line and a horizontal division line can be formed simultaneously. In other words, the plastic substrate 21 can be divided into a lattice shape as shown in FIG. 6C only by bringing the blades 62A and 62B into pressure contact with the plastic substrate 21 once.
[0068]
6A and 6B are process cross-sectional views corresponding to FIGS. 5A and 5B. 5A and 5B and FIGS. 6A and 6B show one section of the blades 52A and 52B and the blades 62A and 62B.
[0069]
6 (a) and 6 (b) show the cross sections of the three blades 62A and 62B, but a grid-like blade in which 36 blades are arranged in both the vertical and horizontal directions is used. May be. In this case, if it is a plastic substrate having a diameter of 116 mm, it is sufficient to perform a single pressure contact process, and step feed is unnecessary.
[0070]
FIG. 7 is a schematic perspective view of an example of an optical element produced by the method for producing an optical element of the present invention. The pitch of the hologram pattern 71 formed on the upper surface of the optical element in the drawing is 1 to 3 μm, and the pitch of the grating pattern 72 formed on the lower surface of the optical element in the drawing is 10 to 20 μm. The groove depth is 0.2 to 0.6 μm. Moreover, after the propagation of the crack 73 is seen on the side surface of the optical element. Since the side surface of the optical element has a broken surface, the side surface is non-uniform and has an effect of irregularly reflecting extraneous light rays. That is, the optical element can scatter unwanted light on the side surface. Therefore, when the semiconductor laser device having the optical element is used for an optical pickup, undesired light is scattered on the side surface of the optical element, so that the undesired light does not enter the light receiving element of the optical pickup and noise is generated. Can be reduced.
[0071]
【The invention's effect】
As apparent from the above, in the method for manufacturing an optical element of the present invention, the first and second blades are pressed against the plastic substrate, cracks are formed between the plurality of optical elements, and then a force is applied to the plastic substrate. Since the plurality of optical elements are separately separated, it can be manufactured at low cost and the plastic substrate can be divided at high speed.
[0072]
In addition, since a force is applied to the plastic substrate having cracks between the plurality of optical elements to separate the plurality of optical elements individually, it is possible to prevent the optical elements from being burred.
[0073]
In one embodiment of the method of manufacturing an optical element, when the first and second blades are pressed against a plastic substrate, the holder is thinner than the plastic substrate. Can be blocked.
[0074]
In one embodiment of the method of manufacturing an optical element, the holder for holding the plastic substrate is made of the same material as the plastic substrate and has the same thickness as the plastic substrate. The processing conditions can be made the same.
[0075]
Since the manufacturing method of the optical element of one embodiment has a step of attaching an adhesive sheet to the entire surface of one surface of the plastic substrate, even if the plastic substrate is divided and a plurality of optical elements are separated individually, Optical elements do not dissipate.
[0076]
In the optical element manufacturing method of one embodiment, since the number of the first blades is plural and the number of the second blades is plural, it is possible to efficiently crack the plastic substrate.
[0077]
The method for manufacturing an optical element of one embodiment, the first, since the second blade is formed in a lattice pattern, first, by a second blade only it is once pressed against the plastic substrate, the lattice-like plastic substrate It can be made into a state that can be divided into two.
[0078]
[0079]
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the principle of a method for producing an optical element of the present invention.
FIG. 2 is an explanatory view when a plastic substrate is divided in the method of manufacturing an optical element of the present invention.
FIGS. 3A to 3G are process diagrams of an optical element manufacturing method according to an embodiment of the present invention.
4 (a) to 4 (d) are process diagrams of an optical element manufacturing method according to another embodiment of the present invention.
FIGS. 5A to 5D are process diagrams of a method of manufacturing an optical element according to another embodiment of the present invention.
FIGS. 6A to 6C are process diagrams of a method of manufacturing an optical element according to another embodiment of the present invention .
FIG. 7 is a schematic perspective view of an optical element produced by the optical element manufacturing method of the present invention.
FIGS. 8A to 8G are process diagrams of a conventional method of manufacturing an optical element.
[Explanation of symbols]
1, 21, 31 Plastic substrate 2A, 52A, 62A First blade 2B, 52B, 62B Second blade 33, 43 Holder 51 Acrylic substrate

Claims (10)

A step of holding a plastic substrate on which a plurality of optical elements are formed with a holder from around the plastic substrate;
Positioning the plastic substrate between the first and second blades facing each other;
Pressing the first and second blades against the plastic substrate and forming a crack between the plurality of optical elements;
Applying a force to the plastic substrate, method of manufacturing an optical element, characterized in that a step of individually separately separating the plurality of optical elements. In the manufacturing method of the optical element according to claim 1,
The method of manufacturing an optical element, wherein the holder is thinner than the plastic substrate. In the manufacturing method of the optical element according to claim 1,
The holding device is made of the same material as the plastic substrate and has the same thickness as the plastic substrate. In the manufacturing method of the optical element according to any one of claims 1 to 3,
A step of attaching an adhesive sheet to the entire surface of one surface of the plastic substrate between the step of making cracks between the plurality of optical elements and the step of separating the plurality of optical elements individually. A method for producing an optical element characterized by the above. In the manufacturing method of the optical element according to any one of claims 1 to 4,
The method of manufacturing an optical element, wherein the number of the first blades is plural and the number of the second blades is plural. In the manufacturing method of the optical element according to any one of claims 1 to 4,
The method for manufacturing an optical element, wherein the first and second blades are formed in a lattice shape. In the manufacturing method of the optical element according to any one of claims 1 to 6,
An optical element manufacturing method, wherein optical patterns are formed on both surfaces of the plastic substrate. In the manufacturing method of the optical element according to any one of claims 1 to 7,
The method of manufacturing an optical element, wherein the optical element is a diffraction grating having a pitch of 20 μm or less. In the manufacturing method of the optical element according to any one of claims 1 to 8,
The method of manufacturing an optical element, wherein the plastic substrate is an acrylic resin. In the manufacturing method of the optical element according to any one of claims 1 to 9,
The method of manufacturing an optical element, wherein the holder is annular.

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