JP4319062B2 - Microlens substrate manufacturing method and use thereof - Google Patents

Description

  The present invention uses a microlens substrate provided with a microlens on a transparent substrate, a microlens substrate manufacturing method including a microlens array including a plurality of microlenses, and a microlens substrate manufactured by the manufacturing method. The present invention relates to an optical component and an optical device including the optical component.

  In recent years, an optical component including a microlens substrate in which a microlens is formed on a transparent substrate has been provided. For example, in a liquid crystal projector that projects an image on a screen, a two-layer microlens substrate is mounted on the liquid crystal display element to increase the brightness.

  As a manufacturing method of the two-layer microlens substrate as described above, for example, a manufacturing method by 2P (Photo-Polymerization) molding as shown in Patent Document 1 or a manufacturing method by a self-alignment exposure method as shown in Patent Document 2 It has been known. Below, the manufacturing method of the microlens substrate by these two manufacturing methods is demonstrated with reference to drawings, respectively.

  First, a method for manufacturing a microlens substrate by 2P molding, represented by Patent Document 1, will be described with reference to FIG.

  First, as shown in FIG. 12A, the first ultraviolet curable resin 205 is placed between the first glass substrate 201 and the first stamper 203 on which the reverse pattern of the first microlens is formed. Dripping. Next, as shown in FIG. 12B, the first glass substrate 201 is pressed against the first stamper 203, and the first ultraviolet curable resin 205 is bonded to the first stamper 203 and the first glass substrate 201. Then, the first ultraviolet curable resin 205 is cured by irradiating ultraviolet rays through the first glass substrate 201. Then, as shown in FIG. 12C, the first microlens 208 is formed on the first glass substrate 201 by peeling the first stamper 203 from the first glass substrate 201. One microlens substrate 210 is manufactured.

  The second microlens substrate is formed in the same manner as the first microlens substrate formation method. Specifically, first, as shown in FIG. 12D, a second ultraviolet ray is interposed between the second glass substrate 202 and the second stamper 204 on which the reverse pattern of the second microlens is formed. A cured resin 206 is dropped. Next, as shown in FIG. 12E, the second glass substrate 202 is pressed against the second stamper 204, and the second ultraviolet curable resin 206 is applied to the second stamper 204, the second glass substrate 202, and the like. The second ultraviolet curable resin 206 is cured by spreading and irradiating ultraviolet rays through the second glass substrate 202. Then, as shown in FIG. 12F, the second microlens 209 is formed on the second glass substrate 202 by peeling the second stamper 204 from the second glass substrate 202. A two-microlens substrate 211 is manufactured.

  Subsequently, as shown in FIG. 12G, a third ultraviolet curable resin 207 is dropped between the first microlens substrate 210 and the second microlens substrate 211. Then, as shown in FIG. 12 (h), the first microlens substrate 210 and the second microlens substrate 211 are pressed, and the third ultraviolet curable resin 207 is applied to the first microlens substrate 210 and the second microlens substrate. The two-layer microlens substrate 212 can be manufactured by spreading between the layers 211 and then irradiating ultraviolet rays to cure the third ultraviolet curable resin 207.

  Next, a manufacturing method of a microlens substrate represented by Patent Document 2 by a self-alignment exposure method will be described with reference to FIG.

  The self-alignment exposure method is a method of forming a pattern of the second microlens using the first microlens, and the first microlens is formed by 2P molding. Specifically, first, as shown in FIG. 13A, the first microlens 306 is formed on the first glass substrate 301 by the same method as in Patent Document 1 described above. Subsequently, as illustrated in FIG. 13B, the first microlens 306 is formed between the first glass substrate 301 on which the first microlens 306 is formed and the second glass substrate 302. A second ultraviolet curable resin 304 having a refractive index higher than that of the ultraviolet curable resin is dropped. And as shown in FIG.13 (c), after pressing the 2nd glass substrate 302 and expanding the 2nd ultraviolet curable resin 304, an ultraviolet-ray is irradiated and the 2nd ultraviolet curable resin 304 is hardened, A first microlens substrate 308 is manufactured.

  Next, the formation of the second microlens will be described with reference to FIGS.

  First, as shown in FIG. 13D, a negative resist 309 is applied on the first microlens substrate 308 manufactured as described above. Next, the first microlens substrate 308 is irradiated with ultraviolet rays 310. Next, as shown in FIG. 13E, the ultraviolet rays 310 are condensed on the negative resist 309 by the first microlens 306, and the negative resist 309 at the condensing portion is exposed.

Subsequently, as shown in FIG. 13F, irradiation is performed by changing the incident angle of the ultraviolet ray 310 with respect to the first microlens substrate 308 to expose another portion of the negative resist 309. At this time, the exposed thickness of the negative resist 309 can be controlled by controlling the irradiation intensity of the ultraviolet ray 310. Next, as shown in FIG. 13G, after patterning the negative resist 309 by controlling the incident angle and irradiation intensity of the ultraviolet light 310, the unexposed negative resist 309 is removed by development, whereby the second micro-resist 309 is removed. A resist pattern for the lens 307 is formed. Thereafter, as shown in FIG. 13H, the resist pattern of the second microlens 307 is transferred to the first microlens substrate 308. Then, as shown in FIG. 13 (i), a third glass substrate 303 is prepared, and a third ultraviolet curable resin 305 is dropped between the third glass substrate 303 and the second microlens 307. . Finally, as shown in FIG. 13 (j), the third glass substrate 303 and the second microlens 307 are bonded to each other with the third ultraviolet curable resin 305 to thereby form the two-layer microlens substrate 311. Can be manufactured.
JP 2000-147500 A (published May 26, 2000) JP 2003-294912 A (published October 5, 2003)

  However, the following problems occur in the manufacturing method of the microlens substrate described in Patent Documents 1 and 2 above.

  First, in the manufacturing method disclosed in Patent Document 1 described above, the first microlens substrate 210 on which the first microlens 208 is formed and the second microlens substrate 211 on which the second microlens 209 is formed. Are produced as separate parts, and then two microlens substrates are bonded together to produce a two-layer microlens substrate 212. However, this Patent Document 1 does not disclose a method for aligning microlenses, and when the microlenses are simply stacked and bonded as they are, the first microlens 208 and the second microlens 209 are not aligned. An optical axis shift occurs between them. At this time, when used in a liquid crystal display element, the light utilization efficiency is lowered, and the resolution is lowered due to the color mixture of each light flux.

  This problem is caused by, for example, forming a separate alignment mark at the time of manufacturing each microlens substrate, and incorporating an alignment mark observation system into the bonding apparatus, so that the two microlens substrates are bonded together. Although it is possible to solve the problem by aligning and pasting, there is a problem that a high-accuracy positioning device is required and this causes an increase in cost.

  In the manufacturing method disclosed in Patent Document 2, the exposure light is condensed by the first microlens 306 to expose the negative resist 309 and the second microlens 307 is patterned. The optical axis is not shifted between the lens 306 and the second microlens 307. However, since it is necessary to control the incident angle and irradiation intensity of the ultraviolet ray 310 with high precision during the exposure of the second microlens 307, there is a problem that the exposure optical system becomes complicated and increases the cost.

  Furthermore, the demand for downsizing and thinning of devices equipped with a microlens substrate has become stronger in recent years, and the thickness of the microlens substrate tends to be thinner. However, in the manufacturing method shown in Patent Document 1 and the manufacturing method shown in Patent Document 2, the first microlens forming step, that is, in 2P molding, a step of peeling the stamper from the glass substrate after curing the ultraviolet curable resin. Exists. In this step, since stress is applied to the glass substrate, if the glass substrate is thinned, the glass substrate cannot withstand this stress and is damaged. Therefore, in 2P molding, there is a limit to thinning the glass substrate.

  In addition, in the manufacturing methods disclosed in Patent Documents 1 and 2, since the first microlens and the second microlens are formed in separate steps, the number of manufacturing steps increases and the manufacturing time increases. There is also a problem that it is not suitable for mass production.

  The present invention has been made in view of the above-described problems, and an object thereof is to produce a microlens substrate in which microlenses aligned on both surfaces of a transparent substrate with high precision are formed with fewer manufacturing steps. It is an object of the present invention to provide a method of manufacturing a microlens substrate that can be manufactured, an optical component using the microlens substrate manufactured by the manufacturing method, and an optical device including the optical component.

  As a result of intensive studies in view of the above problems, the present inventors have arranged a light-shielding mask having an opening of a predetermined size on a transparent substrate having a photosensitive material layer formed on both sides, and this light shielding. When the transparent substrate was irradiated with exposure light through a mask, the phenomenon that microlenses were formed on both sides of the transparent substrate was uniquely found, and the present invention was completed.

  That is, a method for manufacturing a microlens substrate according to the present invention is a method for manufacturing a microlens substrate including at least one microlens on each of both surfaces of a transparent substrate, in order to solve the above-described problem. A step of forming a first photosensitive material layer on one surface of the substrate, a step of forming a second photosensitive material layer on the other surface of the transparent substrate, and light between the transparent substrate and the light source. A step of arranging a light-shielding means having an opening for transmitting light, and exposure to the first photosensitive material layer and the second photosensitive material layer formed on both surfaces of the transparent substrate through the opening of the light-shielding means. And a step of exposing the first photosensitive material layer and the second photosensitive material layer by irradiating light, and a step of developing the first photosensitive material layer and the second photosensitive material layer. Yes.

  According to said structure, the multi-layer microlens can be formed as alignment by one exposure light irradiation. For this reason, it is possible to reliably prevent the occurrence of deviation of the optical axes of a plurality of microlenses (for example, the first microlens and the second microlens) without using a special process or device. Therefore, for example, it is not necessary to provide a highly accurate positioning device. In addition, since a plurality of microlenses can be formed simultaneously, it is possible to prevent the exposure optical system from becoming complicated. As a result, it is possible to prevent a cost increase related to the manufacturing process and the equipment to be used.

  In addition, since a plurality of layers of microlenses can be simultaneously formed on the transparent substrate, the manufacturing time can be reduced.

  Furthermore, according to the manufacturing method according to the present invention, since the “step of peeling the glass substrate from the stamper” included in the manufacturing process by 2P molding is not included, no stress is applied to the transparent substrate. For this reason, it is possible to use a thinner transparent substrate as compared with the conventional case, and it is possible to manufacture a microlens substrate that is smaller and thinner.

  In the method for manufacturing a microlens substrate according to the present invention, the light shielding unit may be disposed at a predetermined distance from the transparent substrate on which the first photosensitive material layer and the second photosensitive material layer are formed. preferable. In the method for manufacturing a microlens substrate according to the present invention, it is preferable that the light shielding means is disposed substantially parallel to the transparent substrate.

  According to said structure, a some microlens can be formed on a transparent substrate reliably and easily.

  In the method for manufacturing a microlens substrate according to the present invention, the exposure light is preferably parallel light.

  According to said structure, the area of the exposure light irradiated to the 1st photosensitive material layer and the 2nd photosensitive material layer which were formed on both surfaces of the transparent substrate becomes the same area. For this reason, even when the thickness of the transparent substrate is different, a microlens substrate in which microlenses having substantially the same size are formed on both surfaces of the transparent substrate can be manufactured without changing the exposure system.

  In the method for manufacturing a microlens substrate according to the present invention, it is preferable that the light shielding unit includes a plurality of openings.

  According to said structure, the microlens board | substrate with which the microlens was formed in the array form on the transparent substrate can be manufactured easily.

  In the method for manufacturing a microlens substrate according to the present invention, it is preferable that the sizes of the plurality of openings provided in the light shielding unit are different.

  According to said structure, the microlens board | substrate provided with the several microlens from which a magnitude | size differs can be manufactured easily.

  Moreover, in order to solve the said subject, the microlens board | substrate which concerns on this invention is manufactured by the manufacturing method of one of the said microlens board | substrates.

  According to the above configuration, it is possible to reliably and inexpensively obtain a microlens substrate having a plurality of microlenses aligned with high accuracy on both surfaces of the transparent substrate without any deviation of the optical axis. Therefore, the microlens substrate according to the present invention can be used for an optical component or an optical device by making use of the characteristics.

  An optical component according to the present invention includes the microlens substrate in order to solve the above problems.

  According to said structure, the optical component provided with the micro lens aligned with high precision can be manufactured.

  Moreover, in order to solve the said subject, the optical apparatus which concerns on this invention is equipped with the said optical component, It is characterized by the above-mentioned.

  According to said structure, the optical apparatus which has an optical component provided with the micro lens aligned with high precision can be manufactured.

  As described above, the manufacturing method of the microlens substrate according to the present invention includes the step of forming the first photosensitive material layer on one surface of the transparent substrate, and the second photosensitive material layer on the other surface of the transparent substrate. Forming a light shielding means having an opening for transmitting light between the transparent substrate and the light source, and forming on both surfaces of the transparent substrate through the opening of the light shielding means. A step of irradiating the first photosensitive material layer and the second photosensitive material layer with exposure light to expose the first photosensitive material layer and the second photosensitive material layer; And a step of developing the second photosensitive material layer, so that a plurality of microlenses can be formed by one exposure light irradiation. The effect of being able to form Unlikely to. In addition, since a plurality of microlenses can be formed in the same process, the manufacturing time can be shortened. In addition, since an alignment mechanism is not required in the exposure apparatus, the cost of the exposure apparatus can be reduced. In addition, since no stress is applied to the transparent substrate, a thin glass substrate can be used, so that the optical component can be thinned.

  Hereinafter, an embodiment of the present invention will be described below with reference to the drawings. First, after describing a characteristic microlens substrate manufacturing method of the present invention, an optical component and an optical device using the microlens substrate manufactured by the microlens substrate manufacturing method will be described.

(1) Manufacturing Method of Microlens Substrate Various methods have been disclosed as methods for forming a microlens on a transparent substrate. The present inventors have configured the microlens substrate according to the configuration shown in FIG. Created a method of manufacturing. That is, the first photosensitive material layer 2 is formed on one surface of the transparent substrate 1, the second photosensitive material layer 3 is formed on the other surface of the transparent substrate 1, and a predetermined distance from the transparent substrate 1. When the light shielding mask 4 having the opening 5 is disposed and the exposure light 6 is irradiated to the transparent substrate 1, the first photosensitive material layer 2, and the second photosensitive material layer 3 through the opening 5. 2 found that a microlens made of a photosensitive material having a curved surface pattern as shown in FIG. The phenomenon that the photosensitive material layers 2 and 3 are curved on both surfaces of the transparent substrate 1 is caused by some action at the interface between the photosensitive material and the transparent substrate, and the present inventors based on this phenomenon. A new method for manufacturing microlens substrates has been developed.

  Specifically, as shown in FIG. 3, the microlens substrate manufacturing method according to the present embodiment includes a transparent substrate 11, a first ultraviolet curable resin 12, a second ultraviolet curable resin 13, and an opening 15. A light shielding mask 14 and a light source 17 are used. The transparent substrate 11 is not particularly limited as long as it is a substrate capable of transmitting the ultraviolet rays 16. The first ultraviolet curable resin 12 and the second ultraviolet curable resin 13 may be the same or not, and a conventionally known ultraviolet curable resin can be used. In the present embodiment, description will be made mainly using an ultraviolet curable resin. However, the present invention is not limited to this, and any photosensitive material layer made of a photosensitive material can be used. The opening 15 is for transmitting the ultraviolet rays 16 and is provided in the light shielding mask 14 in the present embodiment, but the number of the openings 15 can be appropriately set as will be described later. The light source 17 is a light source that emits ultraviolet rays 16 for curing the first ultraviolet curable resin 12 and the second ultraviolet curable resin 13.

  Hereinafter, each process in this manufacturing method is demonstrated one by one. First, the first ultraviolet curable resin 12 is applied to one surface of the transparent substrate 11, and the second ultraviolet curable resin 13 is applied to the other surface. As a method of applying these ultraviolet curable resins 12 and 13 to the surface of the transparent substrate 11, a conventionally known spin coating method, dipping method, or the like can be used, and can be appropriately selected. Then, the transparent substrate 11 coated with the first ultraviolet curable resin 12 and the second ultraviolet curable resin 13 and the light shielding mask 14 are substantially parallel to each other, and a predetermined distance (400 μm in this embodiment) is set. They are arranged apart (separated) (FIG. 3A). At this time, it is preferable that the light shielding mask 14 is arranged so that ultraviolet rays are irradiated through the opening 15 at a location where the microlens is to be formed on the transparent substrate 11. The light shielding mask 14 is disposed between the exposure optical system such as the light source 17 and the transparent substrate 11. In this embodiment, the light shielding mask 14 is disposed between the light source 17 and the surface of the transparent substrate 11 to which the first ultraviolet curable resin 12 is applied, but the present invention is not limited to this. Is not to be done. That is, the light shielding mask 14 is arranged on either side of the surface side of the transparent substrate 11 to which the first ultraviolet curable resin 12 is applied and the surface side to which the second ultraviolet curable resin 13 is applied. In other words, it can be appropriately arranged according to the configuration and position of the exposure optical system. Further, the distance between the transparent substrate 11 coated with the ultraviolet curable resin on both sides and the light shielding mask 14 can be set as appropriate.

  Next, as shown in FIG. 3B, in this state, the light shielding mask 14 is irradiated with ultraviolet rays 16 from the light source 17. At this time, the ultraviolet ray 16 passes through the opening 15 of the light shielding mask 14 and is irradiated to the first ultraviolet curable resin 12 applied to the transparent substrate 11, and the first ultraviolet curable resin 12 and the transparent substrate 11 are also irradiated. Then, the second ultraviolet curable resin 13 is also irradiated.

  Therefore, as shown in FIG. 3C, a part of the first ultraviolet curable resin 12 and the second ultraviolet curable resin 13 irradiated with the ultraviolet rays 16 are exposed (the portions shown in the figure are exposed). Where). Subsequently, as shown in FIG. 3D, the first microlens 18 and the second microlens 19 are formed on both surfaces of the transparent substrate 11 by developing and removing the unexposed UV curable resin. Thus, the microlens substrate 10 including the two microlenses 18 and 19 can be manufactured. The first microlens 18 is derived from the first ultraviolet curable resin 12, and the second microlens 19 is derived from the second ultraviolet curable resin 13.

In addition, the height of the lens apex of the microlens can be controlled by the irradiation amount of ultraviolet rays. FIG. 4 is a graph showing the correlation between the irradiation amount of ultraviolet rays and the height of the apex of the microlens. The horizontal axis represents the logarithmic value (mJ / cm ² ) of the UV irradiation amount, and the vertical axis represents the height (μm) of the microlens apex. From the figure, it can be seen that the height of the apex portion of the microlens is proportional to the logarithmic value of the UV irradiation amount.

  Thus, according to the method for manufacturing the microlens substrate according to the present embodiment, either the first ultraviolet curable resin 12 or the second ultraviolet curable resin 13 formed on both surfaces of the transparent substrate 11 is used. By irradiating the ultraviolet rays 16 from the direction, the first microlenses 18 and the second microlenses 19 can be formed on both surfaces of the transparent substrate 11 substantially simultaneously. Accordingly, since a plurality of microlenses can be formed by a single exposure light irradiation, the microlens substrate 20 in which the plurality of microlenses are aligned with high accuracy without being displaced. Can be formed.

  Furthermore, since a plurality of layers of microlenses are formed in the same process, manufacturing time can be shortened. Further, since no alignment mechanism is required in the exposure apparatus, the cost and size of the exposure apparatus can be reduced. In addition, since stress is not applied to the transparent substrate in the microlens formation process as in 2P molding, a thin transparent substrate can be used, and the microlens substrate can be made thinner and smaller.

  Moreover, it is preferable to use parallel light as exposure light. “Parallel light” as used herein refers to exposure light that is irradiated substantially perpendicularly to a transparent substrate having an ultraviolet curable resin layer formed on both sides from an opening of a light shielding mask. That is, it is exposure light that is irradiated substantially perpendicularly to the transparent substrate in a state in which the light source, the opening of the light shielding mask, the ultraviolet curable resin layer, and the transparent substrate are all arranged substantially in parallel.

  Thus, if the exposure light is parallel light, for example, a microlens substrate can be manufactured without being affected by the thickness of the transparent substrate. Specifically, the case where transparent substrates having different thicknesses are used will be described with reference to FIGS. 5 (a) and 5 (b). First, as shown in FIG. 5A, when the thin transparent substrate 21 is used, the ultraviolet light 26 irradiated from the light source 27 passes through the opening 25 provided in the light shielding mask 24 with respect to the thin transparent substrate 21. Then, the first ultraviolet curable resin 22 is exposed, the transparent substrate 21 is transmitted, and the second ultraviolet curable resin 23 is also exposed. On the other hand, as shown in FIG. 5B, even when the thick transparent substrate 31 is used, the ultraviolet light 36 irradiated from the light source 37 to the thick transparent substrate 31 is exposed to the opening 25 provided in the light shielding mask 24. , The first ultraviolet curable resin 22 is exposed, the transparent substrate 21 is transmitted, and the second ultraviolet curable resin 23 can also be exposed.

  That is, by using parallel light as exposure light, even when using transparent substrates having different thicknesses, such as the transparent substrate 21 shown in FIG. 5A and the transparent substrate 31 shown in FIG. The first microlens and the second microlens can be formed on both surfaces of the transparent substrate 31. For this reason, it becomes possible to manufacture microlens substrates having different thicknesses of the transparent substrate, that is, microlens substrates having different functions, without changing the exposure optical system.

  In the method of manufacturing a microlens substrate according to the present invention, for example, a plurality of openings can be provided in the light shielding mask. In this case, a microlens substrate in which a plurality of microlenses are formed in an array on a transparent substrate can be manufactured.

  A specific example is shown in FIG. As shown in the figure, a first ultraviolet curable resin 42 is formed on one surface of a transparent substrate 41, and a second ultraviolet curable resin 43 is formed on the other surface. Then, a light shielding mask 44 is disposed at a certain distance on the surface of the transparent substrate 41 on which the first ultraviolet curable resin 42 is applied. The light shielding mask 44 is provided with a plurality of openings 45, and in the present embodiment, three openings 45, 45, 45 are provided. The light source 47 irradiates the first ultraviolet curable resin 42, the transparent substrate 41, and the second ultraviolet curable resin 43 through the opening 45 of the light shielding mask 44.

  At this time, since three openings 45 are provided, the ultraviolet rays 46 are emitted from the three openings 45, 45, 45 of the first ultraviolet curable resin 42, the transparent substrate 41, and the second ultraviolet curable resin 43. Irradiation is performed to three regions corresponding to each. That is, three exposure regions are formed in each of the first ultraviolet curable resin 42 and the second ultraviolet curable resin 43. As a result, as shown in FIG. 6B, three first microlenses 48, 48, 48 and three second microlenses 49, 49, 49 are formed on the transparent substrate 41 in an array. The manufactured microlens substrate 40 can be manufactured.

  Various conditions such as the number, position, and size of the openings 45 provided in the light shielding mask 44 can be appropriately selected and are not particularly limited. For example, regarding the size of the openings 45, The size is preferably 70 to 100% with respect to the desired lens size. This is because a microlens substrate in which lenses are densely formed can be manufactured. That is, the size of the lens formed on the substrate can be made larger than the size of the opening 45 by increasing the amount of exposure light to be irradiated. For example, as shown in FIG. 6C, an exposure process is performed using a light shielding mask 44 in which the pitch for forming the openings 45 is made equal to the desired lens dimensions and the openings 45 are formed smaller than the dimensions of the lenses 48 and 49. When performing the above, it is possible to manufacture a microlens substrate having no gap between adjacent lenses by appropriately increasing the amount of exposure light to be irradiated.

  In the method for manufacturing a microlens substrate of the present invention, a plurality of openings for the light shielding means may be provided, and the sizes of the openings may be different from each other. In this case, a microlens substrate on which microlenses having different sizes are formed can be manufactured.

  That is, as shown in FIG. 7A, the first ultraviolet curable resin 52 is formed on one surface of the transparent substrate 51, and the second ultraviolet curable resin 53 is formed on the other surface. . Then, a light shielding mask 54 is disposed at a certain distance on the surface of the transparent substrate 51 to which the first ultraviolet curable resin 52 is applied. The light shielding mask 54 has two openings 55a and 55b. Here, the opening 55a and the opening 55b are different in size. In the present embodiment, the opening 55a is formed smaller than the opening 55b. The first ultraviolet curable resin 52, the transparent substrate 51, and the second ultraviolet curable resin 53 are irradiated from the light source 57 through the openings 55 a and 55 b of the light shielding mask 54.

  At this time, the ultraviolet ray 56 is irradiated to two regions corresponding to the two openings 55a and 55b of the first ultraviolet curable resin 52, the transparent substrate 51, and the second ultraviolet curable resin 53, respectively. However, since the sizes of the openings 55a and 55b are different, two exposure regions having different sizes are formed in each of the first ultraviolet curable resin 52 and the second ultraviolet curable resin 53. It will be. As a result, as shown in FIG. 6B, two first microlenses 58a and 58b having different sizes are formed on one surface of the transparent substrate 51. Correspondingly, a microlens substrate 50 in which two second microlenses 59a and 59b of different sizes are formed in an array on the other surface of the transparent substrate 51 can be manufactured. .

  Furthermore, in the method for manufacturing a microlens substrate according to the present invention, it is possible to perform exposure by laminating a plurality of transparent substrates and photosensitive material layers. In this case, since a plurality of microlens substrates can be manufactured by one exposure, there is an advantage that the manufacturing time can be further reduced.

  More specifically, first, as shown in FIG. 8A, a first ultraviolet curable resin 63 is applied to one surface of the first transparent substrate 61. Further, a third ultraviolet curable resin 65 is applied to one surface of the second transparent substrate 62. Then, the first transparent substrate 61 and the second transparent substrate 62 are arranged so that the surfaces on which the ultraviolet curable resin layer is not formed are opposed to each other, and are joined by the second ultraviolet curable resin 64. As a result, the first ultraviolet curable resin 63, the first transparent substrate 61, the second ultraviolet curable resin 64, the second transparent substrate 62, and the third ultraviolet curable resin 65 are sequentially stacked. It will be. Although the ultraviolet curable resin and the transparent substrate are laminated, a light shielding mask 66 is disposed above the first ultraviolet curable resin 63 at a certain distance. The light shielding mask 66 is provided with an opening 67.

  Next, as shown in FIG. 8B, ultraviolet light 68 from a light source 69 is irradiated through an opening 67 to a laminate of an ultraviolet curable resin and a transparent substrate. As a result, as shown in FIG. 8C, the first transparent substrate 61, the second transparent substrate 62, the first ultraviolet curable resin 63, the second ultraviolet curable resin 64, and the third ultraviolet curable resin. 65 can be exposed substantially simultaneously. Then, by removing the ultraviolet curable resin that has not been exposed by development, the microlens substrate 60a in which the first microlens 70 and the second microlens 71 are formed on both surfaces of the first transparent substrate 61, and the second The microlens substrate 60b in which the third microlens 72 and the fourth microlens 73 are formed on both surfaces of the transparent substrate 62 can be manufactured.

  Further, in the method for manufacturing a microlens substrate of the present invention, it is possible to perform exposure in a state where the first transparent substrate 71 and the second transparent substrate 72 are fixed via a spacer 80 as shown in FIG. is there. In this case, the first microlens and the second microlens are formed on the first transparent substrate 71, and the third microlens and the fourth microlens are formed on the second transparent substrate. A multilayer microlens substrate having a lens layer can be manufactured. Even in this case, since the optical axes of the microlenses are not shifted, it is possible to easily align the microlenses.

  In this embodiment, an ultraviolet curable resin is used as the photosensitive material. However, the present invention is not limited to this, and a visible light curable resin that cures with visible light can also be used. In the case where a visible light curable resin is used, a substrate using a material having a relatively low ultraviolet transmittance, for example, a resin material such as polycarbonate or acrylic, can be used as the transparent substrate.

  Since these resin substrates are cheaper than quartz, the manufacturing cost of the microlens substrate can be further reduced. In addition, examples of the photosensitive material include acrylic monomers such as urethane acrylate, epoxy acrylate, polyester acrylate, and polyether acrylate, and mixed compositions in which a photoinitiator is mixed with an epoxy monomer, but are not limited thereto. A conventionally known photosensitive material can be used instead.

(2) Utilization of Microlens Substrate Next, as an example of an optical component on which the microlens substrate manufactured by the method of manufacturing a microlens substrate according to the present invention is mounted, the microlens substrate is used in a liquid crystal display element of a projection type liquid crystal projector. An example of mounting is shown.

  FIG. 10 is a diagram showing a schematic configuration of a projection type liquid crystal projector. FIG. 11 is a diagram in which a microlens substrate manufactured by the method for manufacturing a microlens substrate according to the present invention is mounted on a liquid crystal display element.

  First, a schematic configuration of the projection type liquid crystal projector 500 will be described with reference to FIG. As shown in FIG. 10, the projection type liquid crystal projector 500 is a single plate type using one liquid crystal display element, and includes a white light source 91, a spherical mirror 92, a collimator lens 93, a dichroic mirror 94, a liquid crystal display element 99, a field display. A lens 95 and a projection lens 96 are provided, and an image is projected onto a screen 97. As shown in FIG. 11, the liquid crystal display element 99 includes a microlens substrate 104 and a liquid crystal panel 103.

  The light emitted from the white light source 91 becomes a parallel light beam through the spherical mirror 92 and the collimator lens 93 and is irradiated onto the dichroic mirror 94. The dichroic mirror 94 includes three types of mirrors 94R, 94G, and 94B arranged at different angles. The mirrors 94R, 94G, and 94B selectively reflect light of each wavelength corresponding to red, green, and blue, respectively, and have characteristics of transmitting light of other wavelengths. The mirrors 94R, 94G, and 94B are arranged in this order in the order of red, green, and blue.

  In the projection-type liquid crystal projector 500 configured as described above, the light beams 98 divided by the dichroic mirrors 94R, 94G, and 94B are incident on the liquid crystal display element 99 at different angles. The light beams 98 that have passed through the liquid crystal display element 99 are converted in optical axis by the field lens 95 and projected onto the screen 97 via the projection lens 96.

  Next, the operation of the microlens substrate mounted on the liquid crystal display element 99 will be described with reference to FIG. As shown in FIG. 11, the liquid crystal display element 99 includes a microlens substrate 104 and a liquid crystal panel 103. The microlens substrate 104 is a microlens substrate in which three first microlenses 101, 101, 101 and three second microlenses 102102, 102 are formed on both surfaces of the transparent substrate 100. The liquid crystal display element 99 is formed by bonding.

  The R, G, and B light beams 98 divided by the dichroic mirror 94 are incident on the liquid crystal display element 99 at different angles and are focused by the first microlens 101. The converged R, G, and B light beams 98 are refracted by the second microlens 102 so that their main optical axes are parallel, and then pass through the liquid crystal panel 103.

  As described above, by mounting the microlens substrate 104 having the two-layer structure, the spread of the light flux 98 emitted from the liquid crystal display element 99 can be suppressed, and the light loss due to vignetting in the projection lens 96 is reduced. In addition, the microlens substrate manufactured by the method of manufacturing a microlens substrate according to the present invention is formed by aligning the first microlens 101 and the second microlens 102, and there is no deviation of the optical axis. Therefore, vignetting in the liquid crystal panel 103 can be suppressed, and further improvement in light utilization efficiency can be realized.

  An optical device (for example, a liquid crystal projector) having an optical component (for example, the liquid crystal display element 99) including the microlens substrate manufactured by the method for manufacturing a microlens substrate according to the present invention is also provided. include.

  The present invention also includes a step of forming a photosensitive material layer on both sides of a transparent substrate, a step of disposing a light shielding mask away from the transparent substrate, and exposing the transparent light by irradiating exposure light once through the light shielding mask. A method of manufacturing a microlens substrate having a step of exposing a photosensitive material layer formed on both sides of the substrate and a step of developing the photosensitive material layer, wherein microlenses are formed on both sides of the transparent substrate is also included.

  In this case, the exposure light is preferably parallel light. A step of forming a photosensitive material layer on both sides of the transparent substrate; a step of disposing a light shielding mask away from the transparent substrate; and forming both sides of the transparent substrate by irradiating exposure light once through the light shielding mask. An optical component and an optical device including a microlens substrate manufactured by exposing the photosensitive material layer thus obtained and developing the photosensitive material layer are also included in the present invention.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  As described above, since a high-quality microlens substrate can be easily and inexpensively formed, it can be used in manufacturing industries such as optical equipment and related industries.

It is a figure which illustrates typically the principle of the manufacturing method of the micro lens substrate concerning this embodiment. It is a figure which shows the hardening shape of the photocurable resin in the manufacturing method of the microlens board | substrate which concerns on this Embodiment. It is a figure which illustrates typically the manufacturing method of the micro lens substrate concerning this embodiment. It is a figure which shows the correlation of the height of a microlens and the amount of ultraviolet irradiation in the manufacturing method of the microlens board | substrate which concerns on this Embodiment. In the manufacturing method of the microlens substrate which concerns on this Embodiment, it is a schematic diagram explaining the manufacturing method of a microlens substrate in case the transparent substrate of different thickness is used. In the manufacturing method of the micro lens substrate concerning this embodiment, it is a mimetic diagram explaining the manufacturing method of the micro lens substrate using the shading mask which has a plurality of openings. In the manufacturing method of the microlens substrate which concerns on this Embodiment, it is a schematic diagram explaining the manufacturing method of the microlens substrate using the light shielding mask which has several opening part from which a magnitude | size differs. In the manufacturing method of the micro lens substrate concerning this embodiment, it is a mimetic diagram explaining the manufacturing method which manufactures a plurality of micro lens substrates simultaneously. It is a figure explaining the manufacturing method of the multilayer microlens board | substrate of two or more layers in the manufacturing method of the microlens which concerns on this Embodiment. It is a figure which shows schematic structure of the projection type liquid crystal projector which concerns on this Embodiment. It is a figure explaining the liquid crystal display element which mounts the microlens substrate manufactured using the manufacturing method of the microlens substrate which concerns on this Embodiment. It is a figure explaining the 1st manufacturing method of the conventional microlens board | substrate. It is a figure explaining the 2nd manufacturing method of the conventional microlens board | substrate.

Explanation of symbols

1,11 Transparent substrate 2,12 First UV curable resin (first photosensitive material layer)
3,13 Second ultraviolet curable resin (second photosensitive material layer)
4,14 Shading mask (shading means)
5,15 Opening 6,16 Ultraviolet light (exposure light)
7, 17 Light source 18, 101 First microlens 19 Second microlens 99 Liquid crystal display element (optical component)
104 Microlens substrate 101 First microlens 102 Second microlens 103 Liquid crystal panel 500 Projection type liquid crystal projector (optical device)

Claims (9)

A method of manufacturing a microlens substrate comprising at least one microlens on each of both surfaces of a transparent substrate,
Forming a first photosensitive material layer on one surface of the transparent substrate;
Forming a second photosensitive material layer on the other surface of the transparent substrate;
A step of disposing light shielding means having an opening for transmitting light between the transparent substrate and the light source;
Through the opening of the light shielding means, both the first photosensitive material layer and the second photosensitive material layer formed on both surfaces of the transparent substrate are irradiated with exposure light from one direction, and the first photosensitive material layer is exposed. Exposing the material layer and the second photosensitive material layer substantially simultaneously,
And a step of developing the first photosensitive material layer and the second photosensitive material layer to form a microlens.   2. The microlens substrate according to claim 1, wherein the light shielding means is disposed at a predetermined distance from the transparent substrate on which the first photosensitive material layer and the second photosensitive material layer are formed. Method.   The method for manufacturing a microlens substrate according to claim 1, wherein the light shielding unit is disposed substantially parallel to the transparent substrate.   The method of manufacturing a microlens substrate according to claim 1, wherein the exposure light is parallel light.   The method of manufacturing a microlens substrate according to claim 1, wherein the light shielding unit includes a plurality of openings.   6. The method of manufacturing a microlens substrate according to claim 5, wherein the plurality of openings provided in the light shielding unit have different sizes.   A microlens substrate manufactured by the method for manufacturing a microlens substrate according to claim 1.   An optical component comprising the microlens substrate according to claim 7.   An optical device comprising the optical component according to claim 8.

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