JP2006010973A - Method for manufacturing micro lens array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To arrange micro lenses at a high packing density by using a photomask 1 in which openings 1a are appropriately arranged. <P>SOLUTION: This method uses the photomask 1, in which the openings 1a each having a polygonal shape corresponding to the shape of the micro lenses 2 to be formed are arranged in a pattern corresponding to the closest arrangement pattern of the micro lenses 2. More specifically, the photomask 1 lined up with the openings 1a in the shape formed by individually rotating the micro lenses 2 of the closest-arranged polygonal shape (for example, a regular hexagon) by a prescribed angle (central angle 30°) is used. A photosetting resin on a glass substrate is irradiated with light apart a gap disposed between the same and the photomask 1. As a result, the micro lenses 2 of a shape obtained by rotating the shape of the openings 1a by the prescribed angle (central angle -30°) are formed on the glass substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a microlens array, which is an optical member that is manufactured using a photocurable resin and is used to improve the brightness of a flat panel display.

  Conventionally, as a technique for improving the light use efficiency of a liquid crystal projector, a technique of arranging a microlens array between a light source and a liquid crystal panel is known. Since each microlens of the microlens array is arranged in a one-to-one correspondence with the transmission region of each pixel of the liquid crystal panel, the light from the light source is condensed on the transmission region of each pixel by each microlens, Each pixel can be selectively incident. Since a liquid crystal panel used for a liquid crystal projector has high resolution and a low aperture ratio of a transmission region of each pixel, a bright display can be realized by condensing light from a light source with a microlens.

  Further, in recent years, it is also possible to increase the light utilization efficiency of a transflective LCD (semi-transmissive) LCD used for portable terminals and the like by using a microlens. Since this transflective LCD has a reflective electrode that reflects external light and a transparent electrode that transmits backlight light in one pixel, it displays under bright external light like a normal transmissive LCD. There is no disadvantage that it becomes difficult to see. Furthermore, the transflective LCD has an excellent feature that it can be used as a reflective LCD with the backlight off, and a typical example of its structure is disclosed in Patent Document 1.

  However, in the transflective LCD, the region where the reflective electrode is formed cannot transmit the backlight light, so that the panel brightness becomes darker than the transmissive LCD in a place where there is no bright external light. . Furthermore, although the display capacity tends to increase as a market requirement, the aperture ratio decreases as the resolution increases, so the backlight transmittance decreases and the display brightness decreases.

  In order to avoid such inconvenience, for example, in the transflective LCD of Patent Document 2, a microlens array is installed between the backlight and the LCD panel, so that the backlight light blocked by the reflective electrode is used as the transparent electrode. The light is condensed to increase the panel brightness.

  On the other hand, as a technique for manufacturing a microlens array, a method of manufacturing a lens by molding a resin is generally used. Table 1 shows a list of methods for forming various lenses.

  An exposure-development process ((5) in Table 1) is suitable as a method for forming a microlens array on a large substrate at low cost. FIG. 12 shows a schematic configuration of a microlens array formed by a conventional exposure-development process. In this exposure-development process, first, a photocurable resin 102 such as a negative resist is applied on a substrate 101, and the substrate 101 has openings 103a formed with an opening width a and an opening pitch c. UV exposure is performed through a photomask 103. The exposure at this time is performed with a gap b between the photocurable resin 102 and the photomask 103.

  The light diffracted by the opening 103a of the photomask 103 spreads to the desired lens diameter in the film of the photocurable resin 102 through the gap b. In addition, the exposure intensity changes concentrically around the axis passing through the center of the opening 103a, and is the strongest in the portion through which the central axis of the opening 103a passes, and in the region corresponding to the peripheral portion, that is, the outer peripheral portion of the microlens. It becomes the weakest. As a result, the film thickness of the photocurable resin 102 obtained after the exposure is the thickest at the portion through which the central axis of the opening 103a passes and the thinnest at the peripheral portion, that is, the outer peripheral portion of the microlens. By performing development processing after exposure, an uncured portion of the photocurable resin 102 is removed, and a microlens array is obtained.

  If this method is used, it is possible to form a lens directly on the display panel. In addition, if the lens is directly formed on the display panel, the microlens array can be formed on another substrate, and then the cost can be reduced compared to the case where the microlens array is aligned and bonded to the display panel, and the misalignment margin can be reduced. .

  As an application of the exposure-development process, for example, there is an exposure method disclosed in Patent Document 3. This exposure method is a self-alignment exposure method using a black mask, and FIG. 13 shows a microlens array formed by the exposure method. Specifically, in this exposure method, after forming the black mask 202 on the transparent substrate 201, the flat layer 203 is formed thereon, and the photo-curable resin 204 is further applied thereon. And by irradiating light from the opposite side to the surface in which the black mask 202 was formed in the transparent substrate 201, the photocurable resin 204 is hardened and a microlens array is formed.

  According to this exposure method, since the black mask 202 itself functions as a photomask, it is not necessary to provide a separate photomask, and the position at the time of exposure such as when a microlens is formed on another substrate and bonded to the panel is provided. There is no need for matching. In addition, since there is a gap b between the black mask 202 and the photocurable resin 204, the microlenses can be formed in an array using the light diffracted by the black mask 202.

  However, since the gap b is defined by the thickness of the flat layer 203, it is difficult to control and it is difficult to control the curvature of the lens. In addition, in order to form a thick film lens, it is necessary to expose with a large gap b between the black mask 202 and the photocurable resin 204, and there is a disadvantage that the substrate itself becomes thick. Yes. Further, when the lens is directly formed on the liquid crystal panel, it is necessary to perform exposure through the color filter, and it is difficult to make the lens shape of each pixel uniform.

An exposure method that is not used for manufacturing a microlens array, but that has a complex amplitude distribution in the light transmitted through the photomask and exposes the light intensity distribution to obtain a desired circuit pattern on the substrate. However, it is disclosed in Patent Document 4, for example. According to this exposure method, high-resolution pattern transfer is possible using a conventional proximity exposure machine.
Japanese Patent No. 2955277 Japanese Patent No. 3293589 JP-A-9-166701 JP-A-4-212155

  By the way, when a microlens array whose microlens unit shape is other than a circle (for example, regular hexagon or square) is manufactured by the above-described exposure-development process, the photomask has a shape corresponding to the shape of the microlens (for example, regular hexagon). Those having a square or square opening may be used.

  On the other hand, if you want to increase the filling ratio of the microlenses, if the microlenses are regular hexagons, the microlenses should be arranged in a hexagonal close-packed arrangement, and if they are square microlenses, the microlenses are arranged in a matrix. Should be arranged. For this purpose, in the photomask, openings are formed in regular hexagons corresponding to regular hexagonal microlenses, and the openings are arranged in a hexagonal close-packed manner, or openings are formed in correspondence with square microlenses. It seems that it is only necessary to form a square and arrange the openings in a matrix.

  However, when using a photomask in which openings are arranged in this way, the intervals between adjacent openings have different distances in the vertical, horizontal, and diagonal directions, so the adjacent openings are close in a certain direction. The light from the adjacent opening interferes, and the adjacent opening is far in a certain direction, so that there is a region where the light diffracted by the opening does not reach, and a region that does not function as a lens is formed in any direction It will be. Therefore, even if exposure is performed using the photomask in which the openings are arranged as described above in order to form a microlens other than a circle, there is a problem that the filling ratio of the microlens cannot be increased.

  For example, as shown in FIG. 14A, a photomask 301 having regular hexagonal openings 301a arranged in a hexagonal close-packed manner is used, and a gap is provided between the photomask 301 and the substrate. When the photocurable resin is exposed, as shown in FIG. 14B, the microlens 302 is arranged in a shape in which the shape of the opening 301a is rotated by a predetermined angle (center angle 30 degrees). In this case, the microlens 302 does not have a hexagonal close-packed arrangement, and the filling ratio of the microlens array is reduced.

  For example, as shown in FIG. 15A, a photomask 401 having square openings 401a arranged in a matrix is used, and a gap is provided between the photomask 401 and light on the substrate. When the curable resin is exposed, as shown in FIG. 15B, the microlens 402 is arranged in a shape in which the shape of the opening 401a is rotated by a predetermined angle (center angle 45 degrees). In this case, the microlenses 402 are not arranged in a matrix, which is a close-packed arrangement, and the microlens array has a reduced filling rate.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to arrange microlenses with a high filling rate by using a photomask in which openings are appropriately arranged. An object of the present invention is to provide a method for manufacturing a microlens array.

  In the method for manufacturing a microlens array of the present invention, a photomask having a plurality of openings is used to irradiate a photocurable resin on a substrate with light so that polygonal microlenses are arrayed on the substrate. A method of manufacturing a microlens array to be formed, wherein a photomask in which polygonal openings corresponding to the shape of the microlens are arranged in a pattern corresponding to the closest arrangement pattern of the microlens is used as the photomask. It is characterized by that.

  According to said structure, the opening part of the photomask is formed in the polygonal shape corresponding to the polygonal microlens. For example, when a regular hexagon, a square, and a rhombus are considered as the microlens shape, a regular hexagon, a square, and a rectangle can be considered as the shape of the opening.

  The openings of the photomask are arranged in a pattern corresponding to the close-packed arrangement pattern of the microlenses. Here, the close-packed arrangement pattern of the microlens is, for example, if the microlens shape is a regular hexagon, a square, or a rhombus, the close-packed arrangement pattern includes a hexagonal close-packed arrangement pattern, a matrix-like arrangement pattern, An arrangement pattern in which microlenses are arranged so that two diagonal lines of the rhombus face in the same direction can be considered.

  Therefore, the arrangement pattern of the opening corresponding to the close-packed arrangement pattern of the microlens is, for example, when the microlens is a hexagonal close-packed arrangement pattern, or in the case of a matrix-like arrangement pattern, the opening includes each microlens. An arrangement pattern arranged in a shape rotated by a predetermined angle (for example, a central angle A degree) can be considered. In addition, when the microlenses are arranged in a close-packed shape with a rhombus, the longer side of the two diagonal lines of the rhombus-shaped microlens has a shorter side in the longer diagonal direction and the longer side in the shorter diagonal direction. An arrangement pattern in which openings are arranged in a rectangular shape can be considered.

  In this way, the openings of the photomask are arranged in a pattern corresponding to the close-packed arrangement pattern of the microlenses, so light is irradiated to the photocurable resin on the substrate through each opening of the photomask. When this is done, the polygonal microlenses are arranged in a close-packed manner on the substrate. As a result, a microlens array in which microlenses are arranged with a high filling rate can be realized.

  In addition, the method for manufacturing a microlens array of the present invention includes arraying polygonal microlenses on a substrate by irradiating light onto a photocurable resin on the substrate using a photomask having a plurality of openings. A microlens array manufacturing method for forming a microlens array, wherein, as the photomask, openings that are arranged in a shape in which polygonal microlenses arranged closest to each other are individually rotated by a predetermined angle (for example, a central angle A degree) The photocurable resin is irradiated with light with a gap provided between the photomask and the photomask.

  When the shape of the opening of the photomask is a polygon (for example, a regular hexagon or a square), a gap is provided between the photomask and the photocurable resin on the substrate, and photocuring is performed through the opening of the photomask. When the resin is irradiated with light, there is a condition that the photocurable resin is exposed with a pattern in which the shape of the opening of the photomask is rotated by a predetermined angle (for example, the central angle -A degrees).

  Therefore, in the present invention, by reversely utilizing this, as a photomask, polygonal lenses (for example, regular hexagons and squares) arranged in a close-packed manner are individually rotated by a predetermined angle (for example, center angle A degrees). A photomask having openings arranged in a different shape is used, and a gap is provided between the photomask and the photocurable resin to irradiate the photocurable resin with light. As a result, the photo-curing resin is exposed in a pattern in which the shape of the opening of the photomask is rotated by a predetermined angle (for example, the central angle −A degrees), and as a result, polygonal microlenses are formed in a close-packed arrangement on the substrate. can do. Therefore, it is possible to realize a microlens array in which polygonal microlenses are arranged at a high filling rate.

  Here, the predetermined angle (for example, center angle A degree) is an angle that is half the center angle formed by connecting two adjacent vertices of the polygonal microlens and the center of the circumscribed circle of the polygon. It is desirable. For example, when the microlens is a regular hexagon, the predetermined angle is 30 degrees, and when the microlens is a square, the predetermined angle is 45 degrees. With this setting, when the photo-curable resin is exposed through the opening of the photomask, the polygonal microlenses can be surely arranged on the substrate in the most dense manner. As a result, it is possible to reliably realize a microlens array in which polygonal microlenses are arranged with a high filling rate.

  Further, as an exposure condition for arranging the polygonal microlenses in a close-packed manner, each opening of the photomask is set in a state where the distance between the photomask and the photocurable resin is set to 100 μm or more and 400 μm or less. The photocurable resin is preferably irradiated with light, and a photomask having an opening diameter of 40% or more and 60% or less of the diameter of the microlens to be formed is used as the photomask. It is desirable.

  Further, in the method for manufacturing a microlens array of the present invention described above, if each opening has a square photomask as the photomask, the square microlenses can be arranged in a close-packed manner. If a photomask having a regular hexagonal shape for each opening is used as a mask, regular hexagonal microlenses can be arranged in a close-packed manner.

  According to the present invention, by appropriately setting the arrangement pattern of the openings of the photomask, when the photocurable resin is exposed using the photomask, the polygonal microlenses are arranged in a close-packed manner. Can do. As a result, a microlens array in which microlenses are arranged with a high filling rate can be realized.

An embodiment of the present invention will be described below with reference to the drawings.
In the present invention, in order to arrange the microlenses in a close-packed manner, when exposing the photocurable resin on the substrate using a photomask in which openings are formed, the arrangement pattern of openings in the photomask is appropriately set. There is a feature in the point. Hereinafter, explanation will be given based on this point.

  First, the configuration of a photomask used for manufacturing a microlens array will be described.

  FIG. 1A is a plan view showing a schematic configuration of the photomask 1, and FIG. 1B is a plan view showing an arrangement of microlenses 2 formed using the photomask 1. The photomask 1 has a plurality of openings 1a. Each opening 1 a is formed in a polygonal shape corresponding to the shape of the microlens 2. In the present embodiment, for example, in order to form a regular hexagonal microlens 2, each opening 1 a has a regular hexagonal shape accordingly.

  Further, the opening 1 a is formed in the photomask 1 with a pattern corresponding to the close-packed arrangement pattern of the microlenses 2. Here, when the shape of the microlens 2 is a regular hexagon, the close-packed arrangement pattern of the microlens 2 is a hexagonal close-packed arrangement pattern as shown in FIG. Accordingly, as shown in FIG. 1A, the opening 1a is formed in the photomask 1 in a shape obtained by rotating the individual shapes of the microlenses 2 arranged closest to each other by a predetermined angle (for example, 30 degrees). Yes.

  Next, a method for manufacturing the microlens array of the present invention using the photomask 1 will be described. Note that in order to arrange the microlenses 2 in a close-packed manner, the exposure conditions are optimized, that is, for example, the gap between the photomask 1 and the photocurable resin is optimized, or the opening 1a is opened. It is necessary to set the aperture appropriately, but this point will be described later.

  2A, 2B, and 2C are cross-sectional views showing the manufacturing process of the microlens array of this embodiment. First, as shown in FIG. 2A, a photocurable resin 12 as a forming material of the microlens array 2 is applied on a glass substrate 11 so as to have a thickness of 30 μm. As the photocurable resin 12, 100 parts by weight of a urethane-based acrylate material (made by Shin-Nakamura Chemical Co., Ltd., trade name U-4HA) which is a photopolymerizable monomer, and a polymerization initiator (trade name: Irgacure 369, made by Ciba Geigy Corporation). ) Was added in an amount of 1 part by weight.

  And the gap b between the surface of the photocurable resin 12 apply | coated to the glass substrate 11 and the opposing surface of the photomask 1 is maintained at 400 micrometers, and these are fixed.

  Here, in this embodiment, since the diameter of the desired microlens 2 is about 90 μm and the pitch is about 100 μm, the photomask 1 has an opening diameter a of 50 μm and an opening pitch c of 100 μm. A thing was used. The opening diameter of the opening 1a of the photomask 1 is preferably 40% or more and 60% or less of the diameter of the desired microlens 2, and can be appropriately designed according to the shape of the desired microlens 2. .

Next, using a mercury lamp, a GHI mixed line having a luminance half-value angle of ± 1.5 ° is applied to the photocurable resin 12 through each opening 1a of the fixed photomask 1 at an irradiation amount of 300 mJ / cm ^2. Irradiated. The GHI mixed line is light mainly composed of g-line (wavelength 436 nm), h-line (wavelength 405 nm), and i-line (wavelength 365 nm). By this light irradiation, as shown in FIG. 2B, a cured portion 13 corresponding to the shape of the microlens 2 and an uncured portion 14 are formed on the glass substrate 11.

  Subsequently, the uncured portion 14 of the photocurable resin 12 is subjected to a development process of dissolving and removing it with methyl isobutyl ketone (MIBK). As shown in FIG. A microlens array is formed. The obtained microlens array has a large number of microlenses 2 having a diameter of 80 μm arranged continuously, and each microlens 2 has a lens shape in which the thickness continuously changes concentrically from the central portion. The thickness was 20 μm, the radius of curvature was 80 μm, and the focal length was 250 μm.

  As described above, in the present embodiment, when manufacturing the microlens array, the micromask 2 having a polygonal shape (regular hexagonal shape in the present embodiment) arranged as a photomask 1 is arranged at a predetermined angle (for example, 30 degrees). A photomask 1 having openings 1a arranged in a shape rotated individually is used, and a gap b is provided between the photomask 1 and the photocurable resin 12 on the glass substrate 11 is irradiated with light. When the gap b is provided between the photomask 1 and the photocurable resin 12 to expose the photocurable resin 12, the microlens 2 has a shape in which the shape of the opening 1a is rotated by a predetermined angle (for example, −30 degrees). There are exposure conditions for forming. Therefore, as shown in FIG. 1B, if an opening 1a whose shape is rotated in the opposite direction in advance is formed in the photomask 1 as shown in FIG. 1A, exposure is performed as shown in FIG. Sometimes, the microlenses 2 can be formed in a desired shape and arrangement pattern. Therefore, by exposing the photocurable resin 12 using the photomask 1 of the present embodiment, the regular hexagonal microlenses 2 can be arranged in a close-packed manner.

  Next, optimization of exposure conditions when exposing the photocurable resin 12 using the photomask 1 described above will be described below.

  The opening diameter of the opening 1a of the photomask 1 is a, the opening pitch is c, and the distance (gap) between the photomask 1 and the photocurable resin 12 is b. If the parameters a, b, and c are set appropriately, the light diffracted at the opening 1a of the photomask 1 when the photocurable resin 12 is exposed using the photomask 1 will have a gap b. In the film of the photo-curable resin 12, the microlens array having a high filling rate can be formed because the film spreads to a desired lens diameter. For example, when a = 35 μm, b = 200 μm, and c = 50 μm are set, the microlenses 2 having a diameter of about 100 μm can be formed in an array.

  On the other hand, as shown in FIG. 3, when the opening diameter a of the opening 1a of the photomask 1 is too large with respect to the opening pitch c, or as shown in FIG. 4, the gap b is larger than the opening diameter a. If too much, the boundary portion between adjacent microlenses 2 formed after exposure is not recorded as a clear boundary portion as a result of light from adjacent openings 1a of the photomask 1 interfering with each other. In other words, the microlens array has a waveform cross-sectional shape with continuously changing curvature, and an area that does not function as a lens is formed at the boundary between adjacent microlenses 2.

  Further, as shown in FIG. 5, when the opening diameter a of the opening 1a of the photomask 1 is too small with respect to the opening pitch c, or the gap b between the photomask 1 and the photocurable resin 12 is small. If it is too large, there will be a region where the light diffracted by the photomask 1 will not reach, and similarly, a region that does not function as a lens will be formed at the boundary of the microlens 2. As a result, the lens filling rate of the obtained microlens array is lowered.

  Therefore, in this embodiment, the exposure conditions are optimized based on the following considerations.

In general, when proximity exposure using a photomask is performed, the intensity distribution of light transmitted through the photomask can be calculated by the following procedure. FIG. 6 shows the arrangement of the photomask 1 and the photocurable resin 12. The opening diameter of the opening 1a of the photomask 1 is a, the gap between the mask surface and the photocurable resin 12 is b, the arbitrary position on the mask surface is S, and the arbitrary position on the surface of the photocurable resin 12 is P. , The difference between the length of the line segment SP and the gap b is β, the wavelength of the irradiated light is λ, the area of the opening 1a is σ, the minute area of the S point is dσ, and the light wave at the S point is U ₀ (S ), Where the wave of light at point P is U (P), U (P) can be expressed by the following equation (1).

By making U ₀ (S) constant and the opening 1a a rectangular opening, Equation 1 can be replaced with a form that is easy to calculate. Here, in a coordinate axis whose axes are two directions (X direction and Y direction) orthogonal to each other in a plane parallel to the mask surface, the X coordinate of the S point is ξ, the Y coordinate of the S point is η, and the X of the P point is X The coordinate is x, the Y coordinate of point P is y, the minimum position in the X direction of the opening 1a is ξ1, the maximum position in the X direction of the opening 1a is ξ2, the minimum position in the Y direction of the opening 1a is η1, and the opening When the maximum position in the Y direction of 1a is η2, the above β can be expressed by the following formula 2, and dσ can be expressed by the following formula 3.

If U ₀ (S) is constant at U ₀ and Equations 2 and 3 are substituted into Equation 1, U (P) in Equation 1 can be expressed by the following Equation 4.

  Further, since the light intensity I (P) at the point P can be obtained as the square of the absolute value of the wave amplitude, it can be expressed by the following equation (5).

  Using Equation 4 and Equation 5, the light intensity distribution of the rectangular aperture pattern in the proximity exposure can be calculated. When calculating the light intensity distribution of the proximity exposure using the photomask 1 having the regular hexagonal or square opening 1a, it is easily calculated by expressing each opening 1a as an addition of minute rectangular openings. Can do.

  FIG. 7 is a plan view showing a schematic configuration of a photomask having an opening 1a having a regular hexagonal shape, and FIG. 8 is an explanation schematically showing a light intensity distribution obtained by using Equations 4 and 5. FIG. However, the opening diameter of the opening 1a of the photomask 1 was 50 μm, and the gap b between the photomask 1 and the photocurable resin 12 was 300 μm. Further, the parallelism of the light used for the calculation was set to 1.5 degrees in order to match the actual exposure machine. Further, here, in order to express a light ray of ± 1.5 degrees, calculation was performed by approximating the addition of 13 parallel light beams having different incident angles. FIG. 9 is an explanatory view schematically showing a light intensity distribution when the gap b between the photomask 1 and the photocurable resin 12 is 400 μm. In FIGS. 8 and 9, the light and dark portions correspond to portions with high exposure intensity, and the dark portions correspond to portions with low exposure intensity.

  When the photocurable resin 12 is exposed through the gap b of 300 μm, it can be seen that a regular hexagonal light intensity distribution obtained by rotating the opening pattern of the photomask 1 shown in FIG. 7 by 30 degrees is obtained. When the gap b is 300 μm, the light diffracted by the photomask 1 does not spread to the extent that the light from the adjacent openings 1a overlaps, and there are some areas where the light does not reach the photocurable resin 12. ing. Further, when the gap b is widened to 400 μm, the light diffracted by the photomask 1 is sufficiently spread, so that the area where the light does not reach the photocurable resin 12 is reduced, and a microlens array having a high filling rate can be formed. . On the other hand, when the gap b is less than 100 μm, it is known that there are many regions where light does not reach the photocurable resin 12, and the filling rate of the microlens cannot be increased.

  From the above, it can be said that the gap b is desirably 100 μm or more and 400 μm or less in order to increase the filling ratio of the microlens. In particular, when the gap b is 300 μm or more and 400 μm or less, the filling rate of the microlens can be reliably increased.

  Further, if the equations (4) and (5) are used, the opening diameter a of the opening 1a of the photomask 1 for increasing the filling ratio of the microlens can be optimized. In this embodiment, when the gap b is examined by changing the aperture diameter a in the range of 100 μm or more and 400 μm or less, if the aperture diameter a is 40% or more and 60% or less of the diameter of the formed microlens, the micro It was confirmed that the filling rate of the lens can be increased.

  Thus, parameters such as the shape and opening diameter a of the opening 1a of the photomask 1 and the gap b between the photomask 1 and the photocurable resin 12 can be appropriately designed based on the above calculation. . For this reason, as a microlens array, for example, a microlens array having a square microlens 2 shown in FIG. 10B, a diamond microlens 2 shown in FIG. You can also

  For example, when the square-shaped microlenses 2 are arranged in a close-packed manner, the square-shaped microlenses 2 may be arranged in a matrix as shown in FIG. In this case, as the photomask 1, as shown in FIG. 10A, square-shaped openings corresponding to the shape of the microlens 2 are arranged in a pattern corresponding to the close-packed arrangement pattern of the microlens 2. More specifically, it can be considered that the openings 1a are arranged in a shape in which the individual microlenses 2 arranged in the closest arrangement are rotated by a predetermined angle (center angle 45 degrees).

  Even when the photomask 1 having such an opening shape is used, when the gap b is provided between the photomask 1 and the photocurable resin 12 is irradiated with light, the shape of the opening 1a is set to a predetermined angle (for example, −45 degrees). 10), if the opening 1a whose shape is rotated in the reverse direction in advance is formed in the photomask 1 as shown in FIG. As shown in (b), the microlens 2 can be formed with a desired shape and arrangement pattern during exposure. Therefore, by exposing the photocurable resin 12 using such a photomask 1, the square-shaped microlenses 2 can be arranged in a close-packed manner.

  That is, when the regular hexagonal or square microlenses 2 are arranged in a close-packed manner, as the photomask 1, openings arranged in a shape in which the close-packed polygonal microlenses 2 are individually rotated by a predetermined angle. A photomask 1 having 1a is used, a gap b is provided between the photomask 1 and the photocurable resin 12 may be irradiated with light. The predetermined angle at this time is an angle that is a half of the central angle formed by connecting two adjacent vertices of the polygonal microlens 2 and the center of the circumscribed circle of the polygon (the microlens 2 is a regular hexagon). (60 ° / 2) = 30 °, and if the microlens 2 is square (90 ° / 2) = 45 °).

  Moreover, if each opening part 1a uses a regular hexagonal thing as the photomask 1, if the regular hexagonal microlenses 2 can be arrange | positioned in close proximity and each opening part 1a uses a square-shaped thing. It can be said that the square-shaped microlenses 2 can be arranged in a close-packed manner.

  On the other hand, in the case where the diamond-shaped microlenses 2 are arranged in a close-packed manner, as shown in FIG. 11B, the microlenses 2 may be arranged so that the two diagonals of the rhombus face in the same direction. . At this time, as the arrangement pattern of the openings 1a of the photomask 1 corresponding to the close-packed arrangement pattern of the microlenses 2, as shown in FIG. Among them, an arrangement pattern in which the openings 1a are arranged in a rectangular shape having a short side in the longer diagonal direction and a long side in the shorter diagonal direction can be considered. Even in this case, when the photocurable resin 12 is irradiated with light using the photomask 1, the diamond-shaped microlenses 2 can be arranged in a close-packed manner.

(A) is a top view which shows the schematic structure of the photomask used for manufacture of the microlens which concerns on one Embodiment of this invention, (b) is a microlens formed using the photomask It is a top view which shows arrangement | positioning. (A) thru | or (c) are sectional drawings which show the manufacturing process of the said micro lens. It is sectional drawing which shows the shape of the micro lens formed by exposure, when the opening diameter of the opening part of the said photomask is too large with respect to opening pitch. It is sectional drawing which shows the shape of the micro lens formed by exposure, when the gap between the said photomask and photocurable resin is too large with respect to the opening diameter of the opening part of the said photomask. When the opening diameter of the opening of the photomask is too small with respect to the opening pitch, or when the gap between the photomask and the photocurable resin is too small, the shape of the microlens formed by exposure is changed. It is sectional drawing shown. It is sectional drawing which shows typically the arrangement | positioning relationship of the said photomask and photocurable resin. It is a top view which shows the schematic structure of the photomask whose opening part is a regular hexagon shape. It is explanatory drawing which shows an example of the light intensity distribution in photocurable resin. It is explanatory drawing which shows the other example of the light intensity distribution in photocurable resin. (A) is a top view which shows the other structure of a photomask, (b) is a top view which shows arrangement | positioning of the microlens formed using the photomask. (A) is a top view which shows other structure of a photomask, (b) is a top view which shows arrangement | positioning of the microlens formed using the photomask. It is sectional drawing which shows the schematic structure of the micro lens array formed of the conventional exposure-development process. It is sectional drawing which shows the schematic structure of the micro lens array formed by the other conventional exposure method. (A) is a top view which shows the schematic structure of the conventional photomask, (b) is a top view which shows arrangement | positioning of the microlens formed using the photomask. (A) is a top view which shows the other structure of the conventional photomask, (b) is a top view which shows arrangement | positioning of the microlens formed using the photomask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photomask 1a Opening part 2 Micro lens 11 Glass substrate 12 Photocurable resin

Claims (7)

A method of manufacturing a microlens array in which a polygonal microlens is formed in an array on a substrate by irradiating light onto a photocurable resin on the substrate using a photomask having a plurality of openings. ,
A method of manufacturing a microlens array, wherein a photomask in which polygonal openings corresponding to the shape of a microlens are arranged in a pattern corresponding to a close-packed arrangement pattern of microlenses is used as the photomask. A method of manufacturing a microlens array in which a polygonal microlens is formed in an array on a substrate by irradiating light onto a photocurable resin on the substrate using a photomask having a plurality of openings. ,
As the photomask, a photomask having openings arranged in a shape in which polygonal microlenses arranged closest to each other are rotated by a predetermined angle is used, and the photocuring is performed by providing a gap between the photomasks. A method for producing a microlens array, which comprises irradiating a light-sensitive resin with light.   3. The predetermined angle is a half angle of a center angle formed by connecting two adjacent vertices of a polygonal microlens and a center of a circumscribed circle of the polygon. Of manufacturing a microlens array.   The light is irradiated to the photocurable resin through each opening of the photomask in a state where the distance between the photomask and the photocurable resin is set to 100 μm or more and 400 μm or less. 4. A method for producing a microlens array according to any one of items 1 to 3.   The microlens according to any one of claims 1 to 4, wherein a photomask having an opening diameter of 40% or more and 60% or less of a diameter of a microlens to be formed is used as the photomask. Array manufacturing method.   6. The method of manufacturing a microlens array according to claim 1, wherein each of the openings has a square shape as the photomask.   6. The method of manufacturing a microlens array according to claim 1, wherein each of the openings is a regular hexagonal photomask.

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