JP4510405B2 - Method for forming recess on glass plate surface and method for manufacturing microlens array - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a recess on a glass plate surface and a method for manufacturing a microlens array.
[0002]
[Prior art]
For example, in a liquid crystal display device such as a projector television, the microlens array is used to avoid blocking incident light due to a black matrix and improve light utilization efficiency. Further, in order to further improve the light utilization efficiency and improve the contrast, image quality, etc. of the liquid crystal display device, it is necessary to arrange the microlenses densely.
[0003]
As a manufacturing method of this microlens array, in Patent Document 1, masking is performed on the surface of the glass substrate, and after applying a masking pattern corresponding to the etching pattern, etching is performed until the masking disappears to form the surface of the glass substrate. A method of forming a lens shape and then filling the lens shape forming portion with a resin having a high refractive index is disclosed.
[Patent Document 1]
Japanese Patent No. 3237631 [0004]
[Problems to be solved by the invention]
However, in the method described in Patent Document 1 described above, it is essential to perform a masking process corresponding to an etching pattern before etching, and this masking process forms an etching pattern after masking the glass substrate surface. It is a complicated manufacturing process. In addition, when manufacturing a non-dense microlens array, it is unavoidable to perform a masking agent peeling process after etching. Furthermore, since the masking agent which becomes an impurity of the etching solution is dissolved in the etching solution, the etching efficiency is deteriorated and the usage period of the etching solution is shortened.
[0005]
Such complication of the manufacturing process, removal of the masking agent, deterioration of the etching efficiency and shortening of the use period of the etching solution can be solved without performing the masking process. The present invention provides a masking process on the surface of the glass substrate. It is an object of the present invention to provide a method capable of forming a recess on the surface of the glass substrate without performing it.
[0006]
[Means for Solving the Problems]
In the method according to the present invention, the surface of the glass plate is pressurized with a pointed object to form an indentation in the shape of a recess, and then the glass plate is etched without performing any masking treatment. A method for forming a recess on the surface of a glass plate is characterized in that a recess is formed and enlarged from a pressed portion as a base point. According to the present invention, the concave portion can be formed on the glass plate surface by a simplified method without masking the glass surface . The glass plate may be two bonded glass plates. If necessary, a concave portion may be formed on one side or both sides of the bonded glass plate to produce a microlens array. According to this method, the concave portions can be formed on the bonded glass plate by a simplified method without masking, and the microlenses can be directly arranged.
[0007]
The etching is preferably wet etching, and if it is wet etching, the cost of the etching apparatus is reduced. Further, it is preferable to continue the etching so that the concave portions are formed densely. A microlens array manufactured using such a dense glass plate avoids incident light blocking by a black matrix in a liquid crystal display device or the like, thereby improving light utilization efficiency, and contrast, image quality, etc. of the liquid crystal display device. Can be made high quality. Further, if the shape of the top of the pointed object corresponds to the shape of the surface of the recessed part, it is easy to form the recessed part on the surface shape of the recessed part corresponding to the shape of the pointed object top. Furthermore, the etching is preferably performed by generating fine bubbles in the etching solution. By generating bubbles, the stirring effect of the etching solution can be obtained, and the etching of the glass surface can be made uniform. Moreover, you may perform the said etching by injecting etching liquid to the recessed part formation surface of the glass plate surface. By this injection, the size and depth of the surface shape of the recess can be controlled.
[0008]
Moreover, this invention is a manufacturing method of the micro lens array which has the process of forming a recessed part in the glass substrate surface using the said recessed part formation method.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. As described above, the present invention is a method of manufacturing a microlens array having a step of forming a recess on the surface of a glass substrate, wherein the step of forming the recess is pressurized with a pointed object on the surface of the glass substrate. A method of manufacturing a microlens array, comprising forming a residual stress portion and then etching the glass substrate.
[0010]
The glass that can be used in the method of the present invention is not particularly limited as long as it is a glass that can be used in the production of a microlens array, but soda-lime glass, alkali-free glass, alkali barium glass, borosilicate glass, alkali borosilicate glass, There are glasses having a composition of aluminoborosilicate glass, barium borosilicate glass, aluminosilicate glass, borate glass, silica glass, lead glass and the like.
[0011]
Formation of the concave portion on the glass surface is performed by performing etching after pressing the glass surface with a pointed object. Usually, the pointed object is pressurized on one side of the glass substrate. In this case, a concave portion is formed on one side of the glass substrate. If it is necessary to manufacture microlens arrays by arranging microlenses on both sides of a glass substrate, pressurization with a pointed object on both sides of the glass substrate and etching to form recesses on both sides of the glass substrate Can do.
[0012]
If the microlenses are directly arranged on two bonded glass substrates, the pointed object is pressed on the surface of the bonded glass substrate as described above. In the case where microlenses are arranged on both surfaces of the bonded glass substrate, the concave portions can be formed on both surfaces of the glass substrate by performing etching while applying pressure to both surfaces of the substrate with a pointed object.
[0013]
As the pointed object, a material having a hardness higher than that of glass is preferably used, and materials such as diamond and cemented carbide are exemplified. The shape of the pointed object is not limited to a conical shape, a pyramid shape, or the like, and can be used in the present invention. By this shape, it is possible to control the surface shape of the recess formed by etching described later.
[0014]
For example, in FIG. 1, the surface of the glass substrate 1 is pressed using a conical pointed object, and a circular indentation 2 is formed on the surface of the glass substrate 1. If etching is performed thereafter, the surface shape of the concave portion 3 on the glass surface becomes circular as shown in FIG.
[0015]
Further, when a pressure is applied to the surface of the glass substrate 1 using a quadrangular pyramid-shaped object, the shape of the top of the pointed object in contact with the glass substrate surface is formed on the surface of the glass substrate 1 as shown in FIG. A substantially cross-shaped indentation 4 corresponding to is formed. If etching is performed thereafter, as shown in FIG. 4, a concave portion 5 having a substantially square surface shape with the apex direction of the indentation 4 as an apex angle is formed, and the cross-shaped indentation 4 expands as a concave portion on the glass surface. Will be formed. Then, if the etching is continued, the shape of the substantially rectangular surface is enlarged, and the speed of the enlargement is faster than the enlargement of the cruciform indentation 4, so that the cruciform indentation 4 is taken into the substantially square 5. The surface shape of the concave portion of the glass substrate is a substantially quadrangular concave portion as shown in FIG. That is, it is possible to form the surface shape of the recess corresponding to the shape of the top of the pointed object. The shape of the concave portion formed in the glass surface in the depth direction is a shape having a curved bottom, and when etching is continued, the surface shape of the substantially rectangular concave portion 6 is as long as there is no adjacent concave portion. It expands and deforms into a circular shape (not shown).
[0016]
Pressurization of the pointed object to the glass substrate is performed using, for example, a micro Vickers hardness meter. The pressurization should just form the indentation or stress residual part by a pointed object on the glass surface. When the pressed glass substrate is etched, the concave portion is formed and enlarged starting from the indentation or the residual stress portion. In addition, when forming a recessed part on the same etching conditions, it has been confirmed that a larger recessed part is formed, so that a pressurization pressure is large. On the other hand, the time for pressurization is not particularly limited, but it has been confirmed that, as with the pressurization pressure, a large recess is formed as the time becomes longer. The interval at which the glass surface is pressed with the pointed object is determined according to the interval at which the microlenses are arranged.
[0017]
Etching is usually performed by immersing the glass substrate in an etching solution. As the etching solution used for etching, a glass-soluble liquid is used. Preferred etching solutions include hydrofluoric acid, ammonium fluoride, potassium fluoride, sodium fluoride, hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, acetic acid, It is an aqueous solution containing one or more chemicals out of succinic acid and the like. Among them, an aqueous solution having a composition of 2 to 25% by weight of hydrofluoric acid, 2 to 20% by weight of hydrochloric acid and 2 to 20% by weight of sulfuric acid is preferable. When chemicals other than hydrofluoric acid, hydrochloric acid, and sulfuric acid are included in the etching solution, one or more chemicals are added to the aqueous solution. In this case, the addition amount is 2 to 20 weight ratio of ammonium fluoride. 1 to 5 weight ratio of potassium fluoride, 1 to 5 weight ratio of sodium fluoride, 2 to 20 weight ratio of phosphoric acid, 1 to 5 weight ratio of nitric acid, 0.1 to 1 weight ratio of acetic acid, succinic acid Is preferably 0.1 to 1 weight ratio. In addition, in order to prevent sludge generated by the etching treatment from adhering to the glass surface, 0.01 to 0.1 weight ratio of at least one selected from anionic surfactants and amphoteric surfactants is further added. You may do it.
[0018]
The temperature and time of the etching solution for etching are not particularly limited, but the higher the temperature, the shorter the time spent for forming the recess, but it is difficult to control the uniformity of the shape and size of the recess. It becomes.
[0019]
FIGS. 1 and 2 illustrate the glass surface in the case where a concave portion is formed by performing etching after pressing the glass substrate surface with a conical pointed object to form an indentation. If a pointed object is pressed on the surface of the square glass substrate 1 at equal intervals nine times, indentations 2 at equal intervals are formed as shown in FIG. Then, if the glass substrate is etched, a concave portion having a circular surface shape is formed, and if the etching is continued, the concave portion is enlarged. As shown in FIG. 2, nine circular concave portions are densely arranged on the glass substrate. Formed.
[0020]
6 and 7 show sectional views between the glass substrates AA in this step. In FIG. 6, the glass substrate which pressed with the conical pointed object and formed the impression was illustrated. FIG. 7 is a cross-sectional view of a glass substrate in which concave portions are formed by etching this glass substrate. In the glass substrate, substantially semicircular concave portions are formed. The portion where the recess is not formed remains as a factor that lowers the temperature.
[0021]
Further, FIG. 8 is a perspective view of a glass substrate in which the recesses 3 are enlarged by continuing etching, and FIG. 9 is a sectional view of the glass substrate. In this case, it is possible to manufacture a glass substrate in which the concave portion is completely densified and no concave portion is formed on the glass substrate. In addition, the surface shape of the recessed part of this glass substrate becomes a rectangle. In this way, if a plurality of pointed objects are pressed on the glass substrate at equal intervals and etching is continued, the recesses expand as the etching continues, and the recesses on the glass surface become dense or complete. It is possible to form densely.
[0022]
On the other hand, when pressure is applied with a quadrangular pyramid-shaped object instead of the above-described conical-pointed object, the surface shape of the concave portion becomes dense as shown in FIG. If the object is a hexagonal pyramid, the one having a hexagonal concave surface shape becomes dense. That is, if etching is performed after pressurizing with a polygonal pointed object, the concave portion corresponding to the polygonal shape of the pointed object becomes dense. Note that if the densification of the concave portion is unnecessary, the etching may be stopped before the densification.
[0023]
In the etching, it is preferable that fine bubbles are generated in the etching solution. The generation of bubbles in the etching solution includes a bubble generation device in the etching solution storage tank and generates bubbles from the device. Examples of the bubble generating device include a bubble ejection tube for generating bubbles, which will be described later, and a nozzle for ejecting the etching solution containing bubbles. The bubble generating device is installed at the bottom of the etching solution storage tank, and the bubbles are formed into the etching solution. It is preferable to generate a rising liquid flow generated by rising inside the entire etching liquid. As the gas used for the bubbles to be generated, a gas that does not cause defects during etching, such as air, nitrogen, helium, or the like is selected.
[0024]
Even if the etching solution is stirred by this bubble generation and etching is continued, the concentration of the glass dissolved by the etching is not localized in the etching solution, the entire etching solution is homogenized, and the shape dimensions of the concave portions of the glass substrate are uniform. It can be made. In addition, the finer the generated bubbles, the more the surface of the non-recessed surface of the glass substrate is roughened by etching, while the surface of the non-recessed surface is rough. At the same time, the surface of the glass substrate can be planarized.
[0025]
The bubble jet tube described above is preferably the bubble jet tube shown in FIG. The bubble ejection pipe includes a gas introduction pipe 7 for introducing a gas and a plurality of porous bubble ejection pipes 8 connected perpendicularly thereto. The bubbles are ejected from countless bubble ejection holes 9 of the ejection pipe by supplying gas from outside to the bubble ejection pipe 8 through the introduction pipe 7. The diameter of these bubble ejection holes 9 is preferably 10 to 500 μm, and the bubbles generated in this case are fine.
[0026]
On the other hand, as a nozzle for jetting an etching solution containing bubbles (hereinafter referred to as “mixed solution”), the nozzle illustrated in FIG. 11 is preferable. The nozzle includes a main body portion 10 and a liquid introduction portion 11 that is screwed to the main body portion 10, and an orifice 12 is fitted between the main body portion 10 and the liquid introduction portion 11. The main body 10 has a liquid mixture injection hole 13 on the distal end side, a gas-liquid mixing part 14 penetrating from the injection hole 13 toward the base end side of the main body, and a gas introduction hole extending vertically from the gas-liquid mixing part. 15 is provided. On the other hand, the liquid introduction part 11 is provided with a liquid introduction hole 16 from the base end part toward the main body part. The orifice 12 has two orifice holes 17 having a diameter of 1 to 2 mm penetrating inward in the axial direction of the nozzle tip so that the etching liquid ejected from the holes intersects in the gas-liquid mixing section. The hole 17 is inclined inward in the distal direction.
[0027]
In order to eject the mixed liquid from the nozzle, first, the etching liquid is introduced into the gas-liquid mixing section 14 after the liquid introducing hole 16 and the orifice hole 17 through a pipe connected to the liquid introducing hole 16. It ejects from the ejection hole 13. Along with the ejection, gas is introduced from the gas introduction hole 15 to the gas-liquid mixing unit 14 through a pipe connected to the gas introduction hole 15, and after the etching liquid and gas are mixed in the gas-liquid mixing unit 14, the mixed solution is introduced from the ejection hole 13. Erupts. According to the method of ejecting the mixed liquid in this way, the etching process can be continuously performed without clogging the nozzle 13 with nozzles due to clogging of the nozzle in the nozzle 13 with sludge in the etching liquid.
[0028]
The gas is preferably introduced into the nozzle by suction by supplying an etching solution to the nozzle. The gas can be sucked and introduced by forcibly supplying the etching solution to the gas-liquid mixing unit in the nozzle by a liquid pumping device such as a pump, and reducing the pressure in the gas-liquid mixing unit. For example, when a nozzle having a main body volume of 0.8 to 2 cm ³ is placed in an etching solution having a depth of 22 cm, the liquid discharge rate from the nozzle is 3 to 12 L / min. In this case, the liquid pressure introduced into the nozzle is 0.1 to 0.5 MPa and the gas introduction amount is 3.0 to 48.0 L / min. It is preferable that The liquid discharge rate from the nozzle is 5 L / min. When the liquid pressure introduced into the nozzle is 0.3 MPa, the gas is 9.0 L / min. It is sucked and introduced into the mixing section with a moderate introduction amount. Bubbles generated by ejecting the liquid mixture from the nozzle are finer than the method of generating only the bubbles.
[0029]
Etching may be performed by spraying an etching solution onto the recess forming surface of the glass substrate surface. As an aspect of the etching liquid injection, the etching liquid is supplied by supplying the etching liquid instead of the gas supplied to the bubble jet pipe 7 illustrated in FIG. 10, and the mixing from the nozzle illustrated in FIG. 11 is performed. There are modes such as injection of liquid, sealing of the gas introduction hole 15 of the nozzle, or injection of etching liquid from a nozzle that does not have the gas introduction hole 15.
[0030]
Both the jetting of the etching solution and the generation of bubbles in the etching solution may be performed. When the bubbles and the etching liquid are ejected, etching is performed using the nozzle illustrated in FIG. 11 or the porous bubble ejection pipes 8 are alternately formed by two bubble ejection pipes as shown in FIG. In this way, there is a method in which the gas is ejected from one bubble ejection pipe and the etching liquid is ejected from the other bubble ejection pipe.
[0031]
Moreover, the said injection is not limited to what is performed in an etching liquid, You may spray an etching liquid on the glass substrate surface, without immersing a glass substrate in an etching liquid. As described above, when the recess is formed on the surface of the glass substrate by spraying the etchant, the depth of the recess can be made deeper than when the etchant is not sprayed.
[0032]
In order to produce a microlens array using a glass substrate having a recess formed on the surface by the above method, a known method is used. For example, there is a method in which a concave portion is filled with a sulfur-containing acrylate resin, which is an ultraviolet curable high refractive index resin, and cured by ultraviolet rays. FIG. 13 is a cross-sectional view of an example of a microlens array using the method according to the present invention. This microlens array includes a liquid crystal cell 18 having a liquid crystal injection chamber 22 between two glass substrates 20 and 23 bonded together with a sealing agent. A concave portion is formed by the method, and then the high refractive index resin is filled in the concave portion, the microlenses 19 are arranged, and the polarizing plate 24 is fixed to the glass surface on which the lenses are arranged.
[0033]
【The invention's effect】
As described above, according to the method of the present invention, it is possible to form a recess by etching without applying a masking pattern corresponding to the recess formed on the surface of the glass substrate. It will be simplified.
[Brief description of the drawings]
FIG. 1 illustrates the surface of a glass substrate after being pressed with a conical pointed object.
FIG. 2 shows the surface of a glass substrate in which concave portions are formed by etching after pressing with a conical pointed object.
FIG. 3 shows the surface of a glass substrate after being pressed with a quadrangular pyramid.
FIG. 4 shows the surface of a glass substrate in which a concave portion is formed by etching after pressing with a quadrangular pyramid-shaped object.
FIG. 5 shows a glass substrate surface obtained by further etching the glass substrate of FIG.
6 is a cross-sectional view taken along a line AA in FIG.
7 is a cross-sectional view taken along a line AA in FIG.
8 is a perspective view of a glass substrate obtained by further etching the glass substrate of FIG.
9 is a cross-sectional view of the glass substrate of FIG.
FIG. 10 illustrates an example of a bubble ejection pipe.
FIG. 11 illustrates an example of a nozzle that ejects a mixed liquid.
FIG. 12 illustrates a combination of an ejection pipe for ejecting bubbles and an etching solution.
FIG. 13 illustrates an example in which a microlens array is provided in a liquid crystal cell.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 20, 23 Glass substrate 2, 4 Indentation 3, 5, 6 Recess 7 Gas introduction pipe 8 Porous bubble ejection pipe 9 Bubble ejection hole 10 Main body part 11 Liquid introduction part 12 Orifice 13 Mixed liquid ejection hole 14 Gas-liquid mixing part 15 Gas introduction hole 16 Liquid introduction hole 17 Orifice hole 18 Liquid crystal cell 19 Micro lens 21 Black matrix 22 Liquid crystal injection chamber 24 Polarizing plate

Claims (8)

After pressing the surface of the glass plate with a pointed object and forming an indentation in the shape of a recess, the glass plate is etched without any masking treatment, so that the concave portion is based on the portion pressed with the pointed object. A method for forming a recess on the surface of a glass plate, wherein Pressurizing the glass plate surface with a pointed object, to one or both sides of the two bonding surface of the glass plate, after forming the indentation into a concave shape, by etching the glass plate without applying any masking A method for forming a concave portion on the surface of a glass plate, wherein a concave portion is formed and enlarged with a portion pressed by the pointed object as a base point.   The recess forming method according to claim 1, wherein the etching is wet etching.   The recess forming method according to claim 1, wherein the etching is continued so that the recesses are densely formed.   The method for forming a recess according to any one of claims 1 to 4, wherein the surface shape of the recess is a shape corresponding to the shape of the top of the pointed object.   The recess forming method according to claim 3, wherein the etching is performed by generating fine bubbles in the etching solution.   The recess forming method according to claim 3, wherein the etching is performed by spraying an etching solution onto the recess forming surface on the surface of the glass plate.   The manufacturing method of a micro lens array which has the process of forming a recessed part in the glass substrate surface using the method in any one of Claims 1-7.

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