Mold for microlens array, method for manufacturing microlens array using the same, and microlens array manufactured by the method

Abstract

The present invention relates to a mold for a micro-lens array, a method for manufacturing a micro-lens array using the same, and a micro-lens array manufactured by the said method. The invention comprises the steps of: coating a photoresist on a wafer; calculating an exposed area and exposure amount of the photoresist according to the shape and height of the micro-lens to be manufactured; irradiating light toward one surface of the photoresist according to the calculated area and exposure amount; and washing and drying the photoresist after the light irradiation is completed to complete the mold (10) of the micro-lens array.

Description

Technology Field

[0001] The present invention relates to a mold for a micro-lens array, a method for manufacturing a micro-lens array using the same, and a micro-lens array manufactured by the said method. Background Technology

[0003] A microlens array (MLA) is an optical device in which lenses ranging in size from tens to hundreds of micrometers are arranged in a two-dimensional array. It is used for focusing, dispersing, or optical processing of light and plays an important role in various applications such as displays, cameras, medical, and sensors.

[0004] Conventional MLA manufacturing processes generally involve photolithography and molding. The photolithography process applies photoresist (PR) to the wafer surface and creates a lens shape through exposure and development. The molding process uses the etched lens structure as a master mold to form a polymer (e.g., PDMS, SU-8) or glass, and then fabricates the MLA through demolding.

[0005] However, the conventional MLA manufacturing method is costly and difficult to maintain precision because it requires the production of grayscale masks used to form lens curves. In particular, when manufacturing large-area MLAs, the mask size also increases, leading to a problem where the center of the mask warps. Furthermore, while the conventional method is suitable for small-batch production, it suffers from reduced cost and time efficiency in mass production.

[0006] Therefore, there is a need for an MLA manufacturing method that ensures process simplification, large-area manufacturing, and economic feasibility.

[0007] The aforementioned background technology is technical information that the inventor possessed or acquired during the process of deriving the embodiments of the present invention, and it cannot be considered as prior art disclosed to the general public prior to the filing of the embodiments of the present invention. The problem to be solved

[0009] To solve the above problem, the present invention provides a method for manufacturing a micro-lens array mold through a maskless grayscale photolithography process and manufacturing a micro-lens array using the same, and a micro-lens array manufactured thereby. means of solving the problem

[0011] A method for manufacturing a mold of a micro-lens array using a maskless grayscale photolithography method according to one embodiment of the present invention may include: a step of coating a photoresist on a wafer; a step of calculating the exposed area and exposure amount of the photoresist according to the shape and height of the micro-lens to be manufactured; a step of irradiating light toward one side of the photoresist according to the calculated area and exposure amount; and a step of completing the mold (10) of the micro-lens array by washing and drying the photoresist after the light irradiation is completed.

[0012] According to one embodiment of the present invention, the step of calculating the exposed area and exposure amount of a photoresist may include: dividing the depth of a hole in the photoresist corresponding to the height of a microlens to be manufactured into a plurality of layers; calculating the depth according to the radius of each layer of the hole so as to correspond to the shape of the microlens; and calculating the exposed area and exposure amount according to the depth and radius of each layer of the hole.

[0013] According to one embodiment of the present invention, in the step of dividing the depth of the photoresist into a plurality of layers, the depth of the hole may be characterized as increasing as the radius of each layer of the hole decreases relative to one surface of the photoresist.

[0014] According to one embodiment of the present invention, in the step of calculating the area and the amount of exposure, the amount of exposure according to the depth of the photoresist may be calculated according to the regression analysis equation of Equation 1.

[0015] [Mathematical Formula 1]

[0016]

[0017] Here, x represents the depth of the photoresist, and y represents the amount of light exposure.

[0018] According to one embodiment of the present invention, to manufacture a plurality of microlenses, the method may further include the step of calculating different exposed areas and exposure amounts depending on the position of the holes in the photoresist.

[0019] A method for manufacturing a micro-lens array using a maskless grayscale photolithography method according to one embodiment of the present invention may include: a step of preparing a mold of a micro-lens array according to one embodiment of the present invention; a step of introducing a silicone polymer material into a hole formed in the mold of the micro-lens array; and a step of curing the silicone polymer material and then demolding it from the mold of the micro-lens array.

[0020] According to one embodiment of the present invention, in the step of introducing a silicone polymer material, the silicone polymer material may be characterized as being PDMS (Polydimethylsiloxane).

[0021] A micro-lens array according to one embodiment of the present invention can be manufactured by a method for manufacturing a micro-lens array according to one embodiment of the present invention.

[0022] According to one embodiment of the present invention, the microlens in the microlens array may be characterized in that the cross-section of the bottom portion of the microlens is circular and has a hemispherical shape.

[0023] According to one embodiment of the present invention, the microlens in the microlens array may be characterized in that the cross-section of the bottom portion of the microlens is a square shape. Effects of the invention

[0025] A method for manufacturing a micro-lens array according to one embodiment of the present invention can manufacture a multi-height MLA with only a single exposure and, since no mask is used, the manufacturing process can be simplified and manufacturing costs can be saved.

[0026] In addition, the present invention has the advantage of enabling large-area manufacturing with fast exposure speed and high precision.

[0027] In addition, the present invention has the advantage of maximizing image acquisition capability by increasing the fill-factor, which is the ratio of the lens to the micro-lens array, by adjusting the shape of the lens.

[0028] The effects obtainable from the invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the invention belongs from the description below. Brief explanation of the drawing

[0030] FIG. 1 illustrates a flowchart of a method for manufacturing a mold of a micro-lens array according to one embodiment of the present invention. FIG. 2 shows a simplified perspective view of a mold of a micro-lens array according to one embodiment of the present invention. FIG. 3 shows a simplified perspective view of a micro-lens array according to one embodiment of the present invention. FIG. 4 illustrates a cross-sectional view of a hole formed in a photoresist in a method for manufacturing a mold of a micro-lens array according to one embodiment of the present invention. FIG. 5 illustrates a graph of the correlation between the height of the photoresist and the amount of exposure in a method for manufacturing a mold of a micro-lens array according to one embodiment of the present invention. FIG. 6 illustrates a flowchart of a method for manufacturing a micro-lens array according to one embodiment of the present invention. FIG. 7 illustrates the mold map shape of a micro-lens array according to one embodiment of the present invention. FIG. 8 is a photograph of the upper surface of a micro-lens array according to Example 1 of the present invention taken with a microscope. FIG. 9 is a graph showing the height difference of the micro-lenses according to the position of the micro-lens array according to Example 1 of the present invention, and the difference in the radius of curvature between the micro-lens intended to be manufactured and the micro-lens actually manufactured. FIG. 10 is a photograph of the upper surface of a micro-lens array according to Example 2 of the present invention taken with a microscope. FIG. 11 is a graph showing the height difference of the micro-lenses according to the position of the micro-lens array according to Example 2 of the present invention, and the difference in the radius of curvature between the micro-lens intended to be manufactured and the micro-lens actually manufactured. FIG. 12 illustrates a perspective view of a mold of a micro-lens array according to another embodiment of the present invention and a micro-lens array fabricated using the same. FIG. 13 illustrates the mold map shape of a micro-lens array according to another embodiment of the present invention. FIG. 14 shows a photograph of the upper surface of a micro-lens array taken with a microscope and a graph of the height of the micro-lens according to position, according to another embodiment of the present invention. Specific details for implementing the invention

[0031] The present invention will become clear from the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Meanwhile, the terms used in this specification are for describing the embodiments and are not intended to limit the present invention.

[0032] Throughout this specification, the singular form includes the plural form unless specifically stated otherwise in the text.

[0033] Throughout this specification, the terms “comprises” and / or “comprising” as used mean that the mentioned components, steps, actions and / or elements do not exclude the presence or addition of one or more other components, steps, actions and / or elements, and that, unless specifically stated otherwise, they do not exclude other components but may include additional components.

[0034] The present invention will be described in more detail below.

[0036] The present invention relates to a method (S1) for manufacturing a mold (10) of a micro-lens array, a method (S100) for manufacturing a micro-lens array (100) using the mold, and a micro-lens array (100) manufactured by the method.

[0037] In particular, the present invention is characterized by being able to manufacture a micro-lens array (100) comprising a plurality of micro-lenses (110) of different heights and shapes by controlling the amount of exposure without using a mask commonly used in a photolithography process, thereby varying the amount of development of the photoresist.

[0038] FIG. 1 illustrates a flowchart of a method (S1) for manufacturing a mold (10) of a micro lens array according to one embodiment of the present invention, FIG. 2 illustrates a simplified perspective view of a mold (10) of a micro lens array according to one embodiment of the present invention, and FIG. 3 illustrates a simplified perspective view of a micro lens array according to one embodiment of the present invention.

[0039] Referring to FIG. 1, the method may include the steps of coating a photoresist on a wafer (S10), calculating the exposed area and exposure amount of the photoresist (S20), irradiating light (S30), and completing the mold (10) of the micro-lens array (S40).

[0040] The step (S10) of coating a photoresist on a wafer is a process of uniformly applying a photoresist onto the wafer before the photolithography process. Before coating, the wafer may undergo a cleaning process using HF, RCA, etc., and a drying process using a gas such as nitrogen. In addition, a priming process may be added to improve the adhesion between the photoresist and the wafer using HMDS (Hexamethyldisilazane), etc.

[0041] A photoresist can form a layer on the upper surface of a wafer using spin coating, dip coating, slit coating, spray coating, etc. In particular, referring to FIGS. 2 and 3, in the present invention, a silicon polymer material is introduced into a mold (10) of a micro-lens array made of photoresist, cured, and then demolded to manufacture a micro-lens array (100), so the maximum height of the micro-lens (110) may vary depending on the thickness of the photoresist. Accordingly, when coating a photoresist on a wafer, the coating thickness of the photoresist on the wafer can be controlled according to the amount of photoresist sprayed, time, number of layers, etc.

[0042] The step (S20) of calculating the exposed area and exposure amount of the photoresist is a process of calculating the exposed area of ​​the photoresist corresponding to the shape and height of the micro lens (110) to be manufactured, and the exposure amount for forming such an area.

[0043] In particular, in the present invention, the shape of the micro lens (110) to be manufactured can be formed as an intaglio (hole) by using a positive photoresist to remove the exposed portion. Accordingly, the area and amount of exposure to the photoresist can be controlled according to the shape of the micro lens (110) to be manufactured.

[0044] More specifically, the step (S20) of calculating the exposed area and exposure amount of the photoresist may include the step (S21) of dividing the depth of the holes (11) of the photoresist corresponding to the shape and height of the micro lens (110) to be manufactured into a plurality of layers, the step (S22) of calculating the depth according to the radius of each layer of the holes (11), and the step (S23) of calculating the exposed area and exposure amount.

[0045] The step (S21) of dividing the depth of the holes (11) in the photoresist into a plurality of layers is a process of dividing the depth of the holes (11) formed in the photoresist into a predetermined number of layers. While the micro-lens array (100) manufactured through the mold (10) of the micro-lens array of one embodiment of the present invention forms a predetermined curvature, it is difficult to form holes (11) having such curvature when manufactured by exposing the photoresist. Therefore, in order to manufacture a micro-lens array (100) that forms curvature by adjusting the amount of exposure, a plurality of concentric circles having different radii according to the height of the micro-lens (110) can be formed and then manufactured by varying the amount of exposure.

[0046] FIG. 4 illustrates a cross-sectional view of a hole (11) formed in a photoresist in a method for manufacturing a mold (10) of a micro lens array according to an embodiment of the present invention. Referring to FIG. 4, if the radius of the layer becomes smaller as the depth of the hole (11) increases with respect to one side of the photoresist, i.e., the upper side (the upper side of layer 8), the shape of the micro lens (110) manufactured thereby may have a shape of a predetermined curvature. That is, if the depth of the hole increases as the radius of each layer of the hole (11) decreases with respect to one side of the photoresist, the shape of the micro lens (110) manufactured thereby may have a shape of a predetermined curvature.

[0047] Accordingly, the number of layers of the holes (11) in the photoresist can be set differently depending on the curvature of the micro lens (110) to be manufactured. Referring to FIG. 4 (a), the layers formed in the holes (11) of the photoresist can be divided into 8 layers. Or, referring to FIG. 4 (b), the layers formed in the holes (11) of the photoresist can be divided into 16 layers. The number of such layers is not particularly limited, and the number of layers forming the micro lens (110) manufactured by the method of the present invention can be set to be greater than the number that minimizes the step difference so as to form a predetermined curvature, and this can be determined according to the diameter of the micro lens (110).

[0048] The step (S22) of calculating the depth according to the radius of each layer of the hole (11) can be manufactured such that the depths of each layer of the hole (11) are different according to the radius of each layer of the hole (11) according to the shape of the micro lens (110) to be manufactured, so as to correspond to the curvature of the micro lens (110). Referring to FIG. 4, each layer of the hole (11) formed in the photoresist can be manufactured in a cylindrical shape with different radii corresponding to the curvature of the micro lens (110) to be manufactured. The radius of each layer can be set to form the widest radius among the points that contact the curvature of the micro lens (110) to be manufactured. Additionally, referring to FIG. 4 (a) and FIG. 4 (b), each layer of the hole (11) formed in the photoresist can form a second layer (layer 2) that is twice the diameter of the first layer (layer 1), and this can be set to be the same up to the eighth layer (layer 8).

[0049] In particular, referring to FIG. 4 (a) and (b), when the number of layers is increased at the same height, it can be manufactured in a shape that is considerably similar to the curvature of the micro lens (110) to be manufactured.

[0050] The step (S23) of calculating the exposed area and exposure amount is a process of calculating the area and exposure amount to be exposed on one side of the photoresist according to the depth and radius of each layer in the hole (11) formed in the photoresist. As previously mentioned, the present invention is characterized by being able to manufacture a micro-lens array (100) of different heights by adjusting the amount of exposure without using a mask and varying the amount of development of the photoresist (hereinafter, amount of development). Accordingly, the depth of the hole (11) according to the position of the photoresist can be measured, and the corresponding amount of exposure can be adjusted accordingly.

[0051] FIG. 5 illustrates a graph of the correlation between the height of the photoresist and the amount of exposure in a method for manufacturing a mold (10) of a micro-lens array according to one embodiment of the present invention. Here, the height of the photoresist means that the height of the hole (11) decreases according to the amount of development, with the height of the undeveloped surface set to 0 nm. That is, a decrease in the height of the photoresist means that the depth of the hole (11) of the photoresist increases.

[0052] Referring to Fig. 5, the height of the photoresist is inversely proportional to the brightness. That is, as the amount of photoresist developed increases, the height of the photoresist decreases relative to 0. Therefore, as the amount of exposure increases and the amount of development increases, the height of the photoresist decreases.

[0053] In particular, the present invention can represent the relationship between the exposure amount and the height of the photoresist based on regression analysis of the exposure amount and the height of the photoresist. That is, the exposure amount according to the depth of the photoresist to be manufactured can be calculated according to the regression analysis equation of Equation 1 below.

[0054] [Mathematical Formula 1]

[0055]

[0056] Here, x represents the depth of the photoresist, and y represents the amount of light exposure.

[0057] In one embodiment, the regression analysis equation of Equation 1 above can be calculated using Broker's surface profiler. Equation 1 The value is 0.9973, indicating that the model explains a significantly high amount of variability in the dependent variable.

[0058] In addition, the present invention may manufacture a mold (10) of a micro-lens array capable of manufacturing a micro-lens array (100). That is, to manufacture a mold (10) of a micro-lens array in which a plurality of micro-lenses (110) can be formed, light may be exposed to form a plurality of holes (11) in a single photoresist. Accordingly, to manufacture a plurality of micro-lenses (110), the method may further include a step of calculating different exposed areas and exposure amounts depending on the position of the holes (11) in the photoresist. That is, holes (11) of different shapes and depths may be formed in a single photoresist at once.

[0059] The step of irradiating light (S30) is a process of exposing light toward one side of the photoresist according to the calculated area and exposure amount described above. This allows the exposure amount according to the area and depth according to the position of the pre-set hole (11) to be exposed to one side of the photoresist. In particular, in the present invention, when multiple layers are stacked, the exposure amount applied to the bottom layer, that is, the layer with the lowest depth of the photoresist, can be irradiated. Referring to FIG. 4, the first layer (layer 1) is a layer where all layers overlap, and since the exposure amount of the first layer is applied to the part in question and light is irradiated, the amount of development increases. As the number of layers increases and the depth of the relative bottom layer decreases, the corresponding exposure amount decreases, and consequently, the amount of development also decreases. In addition, if each hole (11) forms a different area and depth, multiple holes (11) can be formed differently through selective exposure.

[0060] The step (S40) of completing the mold (10) of the micro-lens array is a process of completing the mold (10) of the micro-lens array by washing and drying the photoresist after the light irradiation is completed. The washing process is a step of removing chemicals remaining after development, and after dissolving and removing the photoresist developed by exposure, the wafer can be washed with DI water, etc. The drying step is a step of removing moisture from the surface of the wafer, and can be dried using nitrogen drying or a spinner.

[0061] A mold (10) of a micro lens array according to one embodiment of the present invention can be manufactured through the above process.

[0063] A method (S100) for manufacturing a micro lens array (100) according to one embodiment of the present invention can be manufactured using the mold (10) of the micro lens array described above.

[0064] FIG. 6 illustrates a flowchart of a method (S100) for manufacturing a micro lens array (100) according to an embodiment of the present invention. Referring to FIG. 6, a method (S100) for manufacturing a micro lens array (100) according to an embodiment of the present invention may include a step of preparing a mold (10) of a micro lens array (S110), a step of introducing a material (S120), and a step of demolding (S130).

[0065] The step (S110) of preparing a mold (10) of a micro-lens array is a process of preparing a mold manufactured by the method of manufacturing a mold (10) of a micro-lens array according to one embodiment of the present invention described above.

[0066] The step of introducing the material (S120) is a process of introducing a silicone polymer material into a hole (11) formed in the mold (10) of the micro-lens array. Here, the silicone polymer material is not particularly limited, but as an example, it may be PDMS (Polydimethylsiloxane). PDMS has the advantages of having high light transmittance, being flexible as it can be manufactured into a curved surface, and being chemically stable, having excellent heat resistance and chemical resistance.

[0067] The demolding step (S130) is a step of introducing a silicone polymer material into a hole (11) formed in the mold (10) of the micro-lens array, curing it, and then demolding it from the mold. In particular, when the silicone polymer material is PDMS, it is easy to manufacture the structure of a complex micro-lens array (100) because it is easy to cure after being injected into the mold in a liquid state.

[0068] In addition, the present invention may include a micro-lens array (100) manufactured by a method (S100) for manufacturing a micro-lens array (100) according to one embodiment.

[0069] Here, the shape of the micro lens (110) in the micro lens array (100) according to one embodiment of the present invention is not particularly limited. In one embodiment, the micro lens (110) may have a hemisphere shape in which the cross-section of the bottom portion of the micro lens (110) is circular. Here, the 'cross-section' is a plane cut by a plane perpendicular to the height of the micro lens (110), and the cross-section of the bottom portion, which is the point where the height of the micro lens is 0, may be formed in a circular shape.

[0070] Alternatively, in another embodiment, the micro lens (110) may have a hemispherical shape in which the cross-section of the bottom portion of the micro lens is square. That is, in the cross-section of the bottom portion of the micro lens (110), the diameter of the hemisphere may be formed to be larger than the length of one side of the square. Accordingly, the micro lens (110) may be formed in the shape of a cut hemisphere up to the part where the diameter of the hemisphere becomes equal to the length of one side of the square. This lens shape can increase the fill-factor, which is the ratio of the lens to the micro lens array (100). In other words, there is an advantage in that the image collection capability can be maximized by increasing the ratio of the micro lens (110) within a limited space.

[0071] The micro lens array (100) manufactured by the above method can be applied to various fields such as optical devices, cameras, 3D imaging systems, micro sensors, etc.

[0073] Hereinafter, a mold (10) of a micro lens array according to one embodiment of the present invention and a micro lens array (100) manufactured using the same will be described.

[0074] Example of implementation

[0075] In the present invention, the exposure device uses the DL-1000HP, and based on Equation 2, the reference exposure amount (1300 mJ / cm²) 2 The actual exposure amount was determined by entering a number between 1 and 255 in ).

[0076] [Mathematical Formula 2]

[0077]

[0079] In addition, AZ4620 was used as the photoresist.

[0080] FIG. 7 illustrates the shape of a mold (10) of a micro lens array according to one embodiment of the present invention.

[0081] (a) of FIGS. 2, FIGS. 3, and FIGS. 7 are each a mold and lens shape that can be manufactured in a hemispherical shape with a circular cross-section of the bottom portion of the micro lens (110) (hereinafter, Example 1), and (b) of FIGS. 2, FIGS. 3, and FIGS. 7 are each a mold and lens shape that can be manufactured in a hemispherical shape with a square cross-section of the bottom portion of the micro lens (110) (hereinafter, Example 2).

[0082] Referring to FIG. 7(a), Example 1 is a shape in which the map of the mold (10) of the micro-lens array is made of 64 layers to form a radius of 512 μm. Referring to FIG. 2(a), it can be seen that a total of 16 holes (11) are formed in the shape of the mold (10) of the micro-lens array manufactured according to FIG. 7(a). When a silicon polymer element material is injected into these holes (11) and then cured and demolded, the shape of the micro-lens array (100) as in FIG. 3(a) can be manufactured.

[0083] Additionally, referring to FIG. 7(b), Example 2 is a shape in which the map of the mold (10) of the micro-lens array can be manufactured to form a radius of 724 μm. Referring to FIG. 2(b), it can be seen that a total of 16 holes (11) are formed in the shape of the mold (10) of the micro-lens array manufactured according to FIG. 7(b). When a silicon polymer element material is injected into these holes (11) and then cured and demolded, the shape of the micro-lens array (100) as in FIG. 3(b) can be manufactured. In particular, FIG. 3(b) is a shape with a fill-factor of 100%, and has the characteristic that all surfaces in the space can be formed as micro-lenses (110).

[0085] FIG. 8 is a photograph of the upper surface of a micro lens array (100) according to Example 1 of the present invention taken with a microscope, and FIG. 9 is a graph showing the height difference of the micro lens (110) according to the position of the micro lens array (100) according to Example 1 of the present invention, and the difference in the radius of curvature between the micro lens (110) to be manufactured and the micro lens (110) actually manufactured.

[0086] Referring to FIG. 8, the micro lens array (100) according to Example 1 is illustrated with radius of curvature of 1300 μm, 1700 μm, 2200 μm, 2700 μm, and 3100 μm. That is, it can be confirmed that a micro lens array (100) with various radii of curvature can be manufactured using the mold (10) of the micro lens array according to the present invention and the method (S100) for manufacturing the micro lens array (100) using the same.

[0087] Referring to FIG. 9(a), the micro lens array (100) manufactured according to Example 1 has a photoresist depth formed differently depending on the exposure amount according to position, and accordingly, the height of the micro lens array (100) manufactured according to position can be formed differently. Therefore, referring to FIG. 9(b), it can be confirmed that the micro lens (110) manufactured according to Example 1 of the present invention has not a large deviation between the height at the targeting radius of the micro lens (110) to be manufactured and the height at the experiment radius of the micro lens (110) actually manufactured.

[0088] FIG. 10 is a photograph of the upper surface of a micro lens array (100) according to Example 2 of the present invention taken with a microscope, and FIG. 11 is a graph showing the height difference of the micro lens (110) according to the position of the micro lens array (100) according to Example 2 of the present invention, and the difference in the radius of curvature between the micro lens (110) to be manufactured and the micro lens (110) actually manufactured.

[0089] Referring to FIG. 10, the micro lens array (100) according to Example 2 is shown to have radius of curvature of 3500 μm, 4000 μm, 4400 μm, 4900 μm, and 5300 μm. That is, it can be seen that a micro lens array (100) with various radius of curvature with a high fill-factor can be manufactured using the mold (10) of the micro lens array according to the present invention and the method (S100) for manufacturing the micro lens array (100) using the same.

[0090] Referring to FIG. 11 (a), the micro lens array (100) manufactured according to Example 2 has a photoresist depth formed differently depending on the exposure amount according to position, and accordingly, the height of the micro lens array (100) manufactured according to position can be formed differently. Therefore, referring to FIG. 11 (b), it can be confirmed that the micro lens (110) manufactured according to Example 2 of the present invention has a constant deviation between the height at the targeting radius of the micro lens (110) to be manufactured and the height at the experiment radius of the micro lens (110) actually manufactured.

[0091] FIG. 12 illustrates a perspective view of a mold of a micro-lens array according to another embodiment of the present invention and a micro-lens array fabricated using the same, FIG. 13 illustrates a mold map of a micro-lens array according to another embodiment of the present invention, and FIG. 14 illustrates a photograph of the upper surface of a micro-lens array according to another embodiment of the present invention taken with a microscope and a graph of the height of the micro-lens according to position.

[0092] Referring to FIG. 12, a micro-lens array (100) manufactured according to embodiments 1 and 2 of the present invention can be manufactured such that different focal lengths (19 in the corresponding embodiment) are formed in a single photoresist depending on the position, and a mold (10) of the micro-lens array (Fig. 12 (a) is embodiment 1, Fig. 12 (c) is embodiment 2) and a micro-lens array (100) using the same can be manufactured (Fig. 12 (b) is embodiment 1, Fig. 12 (d) is embodiment 2). Referring to FIG. 13, the map of the micro-lens array can be formed to implement the same height of the same micro-lens (110) in the same row (Fig. 13 (a) is embodiment 1, Fig. 13 (b) is embodiment 2). Referring to FIG. 14, it can be seen that different heights can be achieved depending on the position of the micro lens (110) (Fig. 14 (a) is Example 1, Fig. 14 (b) is Example 2).

[0093] In conclusion, the micro lens array (100) can be manufactured more effectively through the mold (10) of the micro lens array of the present invention and the method (S100) for manufacturing the micro lens array (100) using the same.

[0095] Although the present invention has been described above by limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0097] 10: Mold of a micro-lens array 11: Hall 100: Microlens array 110: Microlens

Claims

Claim 1 A method for manufacturing a mold of a micro-lens array using a maskless grayscale photolithography method, comprising: a step of coating a photoresist on a wafer; a step of calculating an exposed area and exposure amount of the photoresist according to the shape and height of the micro-lens to be manufactured; a step of irradiating light toward one surface of the photoresist according to the calculated area and exposure amount so as to form a hole shape in the photoresist having a depth and radius corresponding to the shape of the micro-lens; and a step of washing and drying the photoresist after the light irradiation is completed to complete the mold (10) of the micro-lens array; wherein the step of calculating the exposed area and exposure amount of the photoresist comprises: a step of dividing the depth of the hole in the photoresist corresponding to the height of the micro-lens to be manufactured into a plurality of layers; and a step of calculating the depth according to the radius of each layer of the hole so as to correspond to the shape of the micro-lens. A method for manufacturing a mold of a micro-lens array comprising: a step of calculating the exposed area and exposure amount according to the depth and radius of each layer of the hole; wherein, in the step of dividing the depth of the photoresist into a plurality of layers, the depth of the hole becomes deeper as the radius of each layer of the hole becomes smaller relative to one surface of the photoresist. Claim 2 delete Claim 3 delete Claim 4 A method for manufacturing a mold of a micro-lens array according to claim 1, wherein, in the step of calculating the area and exposure amount, the exposure amount according to the depth of the photoresist is calculated according to the regression analysis equation of Equation 1. [Equation 1] Here, x represents the depth of the photoresist, and y represents the amount of light exposure. Claim 5 A method for manufacturing a mold of a micro-lens array according to claim 1, further comprising the step of calculating different exposure areas and exposure amounts according to the position of the holes in the photoresist in order to manufacture a plurality of micro-lenses. Claim 6 A method for manufacturing a micro-lens array using a maskless grayscale photolithography method, comprising: a step of preparing a mold of the micro-lens array according to claim 1, 4, or 5; a step of introducing a silicone polymer material into a hole formed in the mold of the micro-lens array; and a step of curing the silicone polymer material and then demolding it from the mold of the micro-lens array. Claim 7 A method for manufacturing a micro-lens array according to claim 6, wherein, in the step of introducing the silicone polymer material, the silicone polymer material is PDMS (Polydimethylsiloxane). Claim 8 A microlens array manufactured by the method of manufacturing a microlens array according to paragraph 6. Claim 9 In claim 8, the micro-lens array is characterized in that the micro-lens in the micro-lens array has a hemispherical shape in which the cross-section of the bottom portion of the micro-lens is circular. Claim 10 In claim 8, the micro-lens array is characterized in that the micro-lens in the micro-lens array has a hemispherical shape in which the cross-section of the bottom portion of the micro-lens is square.

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