JP2006317788A - Microlens array plate and its manufacturing method, etching method for substrate, optoelectronic device and its manufacturing method, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the light-condensing properties of a microlens with respect to pixel, provided to a microlens array. <P>SOLUTION: A plurality of microlenses are arrayed on the microlens array plate. Each of the plurality of microlenses is provided with a first part which is composed of a first transparent medium having a first refractive index, regulates a first lens curved surface and has either one side shape that is concave or convex; and a plurality of second parts which are integrally formed of the first transparent medium to the first part, respectively prescribe second lens curved surfaces located a little to the surrounding of the first lens curved surface as seen in a plan view on the microlens array plate and respectively have either one side shape that is concave or convex, being the same kind with the above-mentioned one side shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technical field of a microlens array plate suitably used for, for example, an electro-optical device such as a liquid crystal device and a manufacturing method thereof. The present invention further relates to an electro-optical device including the microlens array plate, a manufacturing method thereof, and a technical field of an electronic apparatus including the electro-optical device.

  In an electro-optical device such as a liquid crystal device, for example, a microlens corresponding to each pixel is formed on a counter substrate, or a microlens array plate in which such a plurality of microlenses are formed is attached. . By using such a microlens array plate, bright display is realized in the electro-optical device.

  In order to enable bright display with an electro-optical device such as a liquid crystal device, it is important to efficiently collect the light emitted from the light source onto the pixels. The development of technologies for devising the shape and curvature of lenses has been actively conducted. In particular, it is important to improve the light condensing property in the peripheral part of the microlens. For example, Patent Document 1 discloses a method for manufacturing a microlens composed of a plurality of lenses having different areas. Patent Document 2 discloses a method for manufacturing a microlens made of lenses having two different radii of coaxiality.

JP 2003-139915 A JP 2003-185804 A

  However, in the method for manufacturing a microlens disclosed in Patent Document 1, since a plurality of microlenses are formed in a single process, these radii of curvature are all formed equally, particularly around the microlens. It is not possible to sufficiently improve the light condensing performance in the part. In addition, in the microlens manufacturing method disclosed in Patent Document 2, it is possible to form a lens curved surface having a larger radius of curvature in the peripheral portion of the microlens than the radius of curvature of the lens forming the central portion. However, since it is coaxial, there is a limit to improving the light condensing performance in the peripheral part of the microlens.

  As described above, the conventional microlens has a technical problem that the light condensing property cannot be sufficiently improved particularly in the peripheral portion thereof.

  The present invention has been made in view of, for example, the above-described conventional problems. For example, a microlens array plate that can further improve the light condensing performance with respect to pixels by forming the microlens from a plurality of lenses and the manufacture thereof It is an object to provide a method, an electro-optical device, a manufacturing method thereof, and an electronic apparatus.

  In order to solve the above problems, a microlens array plate of the present invention is a microlens array plate in which a plurality of microlenses are arranged on a transparent substrate, and each of the plurality of microlenses has a first refractive index. A first portion defining a curved surface of the first lens and having one of a concave shape and a convex shape, and integrally with the first portion from the first transparent medium. The second lens curved surface that is formed and defines a second lens curved surface located near the periphery of the first lens curved surface as viewed in plan on the microlens array plate, and is either concave or convex that is the same type as the one shape. And a plurality of second portions each having one of the shapes.

  The microlens array plate of the present invention is disposed to face an electro-optical panel having a pixel array region in which a plurality of pixels are arranged, for example. The electro-optical panel is, for example, a liquid crystal panel included in a liquid crystal device that is an example of an electro-optical device, and more generally, a configuration that does not include a light source such as a backlight among components that constitute the electro-optical device. Contains elements.

  Each of the microlenses arranged on the microlens array plate of the present invention includes, for example, a first portion that defines a first lens curved surface at the center when viewed in plan on the microlens array plate, A plurality of second portions that respectively define the second lens curved surface are provided near the periphery. Each of the first portion and the plurality of second portions is integrally formed from a first transparent medium having a first refractive index, and has one of the same kind of concave and convex shapes, that is, an uneven shape. . Here, “one of the same type of concave and convex” or “the same type of concave and convex” means that if the first part is concave, the second part is also concave. Means that the second part is also convex. These two concave portions (or both convex portions) are preferably connected smoothly, but may have some steps or discontinuities. Typically, the first portion is formed so as to occupy a wider area than the second portion when viewed in plan on the microlens array plate. In other words, the first portion functions as a main lens, and the second portion functions as an auxiliary subordinate lens.

  If each of the microlenses has only the first portion, a plane in contact with the sphere forming the first curved surface defined by the first portion in the peripheral portion of the microlens and the surface of the transparent substrate (that is, the microlens array plate) Is larger than the angle formed by the surface of the transparent substrate and the plane that is in contact with the sphere forming the first lens curved surface defined by the first portion at the center of the microlens. For this reason, the condensing property of the microlens with respect to the light incident on the microlens array plate is lower in the peripheral portion of the microlens than in the central portion. Alternatively, since the peripheral portion of the microlens has a surface that is excessively inclined with respect to the incident light, it does not function properly as a lens or cannot be focused properly toward the center of the pixel.

  However, according to the microlens array plate of the present invention, since the plurality of second curved surfaces are located near the periphery of the first lens curved surface, the lens curved surface in the peripheral portion of the microlens, that is, the sphere forming the second curved surface. The angle formed by the plane in contact with the surface of the transparent substrate (that is, the microlens array plate) can be made smaller than when each of the microlenses has only the first portion. In other words, the lens curved surface in the peripheral part of the microlens can be made smooth or parallel to the transparent substrate (that is, the microlens array plate). Therefore, the light incident on the peripheral part of the microlens can be appropriately condensed. That is, for example, the light can be efficiently condensed on each of a plurality of pixels arranged in the pixel array region of the electro-optical panel arranged to face each other through a liquid crystal layer having a predetermined refractive index.

  In addition, each of the microlenses can be designed not only with the first part but also with a plurality of second parts as design parameters, so that the degree of freedom of design is high and the light condensing performance is further improved. Is possible.

  In one aspect of the microlens array plate of the present invention, each of the plurality of microlenses has a second refractive index different from the first refractive index, and fills or covers the first portion and the plurality of second portions. A second transparent medium is further provided.

  According to this aspect, since the first portion and the plurality of second portions are filled or covered with the second transparent medium having the second refractive index different from the first refractive index, each of the plurality of microlenses is provided. The function as a lens depends on the magnitude relationship between the first refractive index and the second refractive index, in addition to the uneven shape of the first lens curved surface and the second lens curved surface. For this reason, the degree of freedom of design is high, and it is possible to design so as to further improve the light condensing property by combining the first refractive index and the second refractive index.

  For example, if the first refractive index is designed to be larger than the second refractive index, the first lens curved surface and the second lens curved surface are formed in a convex shape on the transparent substrate, and these surfaces are formed on the second transparent medium having a low refractive index. By covering with, a convex lens structure can be obtained.

  On the contrary, if the first refractive index is designed to be smaller than the second refractive index, the concave first lens curved surface and the second lens curved surface are formed on the transparent substrate, and the inside thereof is formed by a high refractive second transparent medium. By satisfying this, a convex lens structure can be obtained.

  Note that the second transparent medium may be an adhesive, or a resin other than the adhesive, air, or the like.

  In another aspect of the microlens array plate of the present invention, the center of the sphere forming the first lens curved surface is positioned at the center of each of the plurality of microlenses when viewed in plan on the microlens array plate. To do.

  According to this aspect, the light incident on the central portion of each of the plurality of microlenses is collected by the first portion that defines the first lens curved surface. Since the first lens curved surface has a gentle curvature with respect to the surface of the microlens array substrate at the center of the microlens, it can be efficiently condensed.

  In another aspect of the microlens array plate of the present invention, the center of the sphere forming the second lens curved surface is viewed from the center of the sphere forming the first lens curved surface when viewed in plan on the microlens array plate. Located off the periphery.

  According to this aspect, the light incident on the positions outside the periphery of the first lens curved surface of each of the plurality of microlenses is collected by the second portion that defines the second lens curved surface. Here, the centers of the spheres forming the second lens curved surface are each positioned away from the center of the sphere forming the first lens curved surface as viewed in plan on the microlens array plate. Therefore, since the second lens curved surface is almost parallel to the surface of the microlens array substrate in the peripheral portion of the microlens, the second lens curved surface can be efficiently condensed.

  In another aspect of the microlens array plate of the present invention, the second lens curved surface occupies each corner of the plurality of microlenses.

  According to this aspect, typically, one microlens is provided with four second lens curved surfaces, and at this time, the four corners of one microlens are respectively occupied by the second lens curved surface. In this case, since the second lens curved surface is almost parallel to the surface of the microlens array substrate at the four corners of the microlens, the second lens curved surface can be efficiently condensed. That is, the light incident on the four corners of the microlens can be reliably collected by the second lens curved surface.

  In another aspect of the microlens array plate of the present invention, the radius of curvature of the second lens curved surface is smaller than the radius of curvature of the first lens curved surface.

  According to this aspect, since the radius of curvature of the second lens curved surface is smaller than the radius of curvature of the first lens curved surface, for example, when the first lens curved surface is formed relatively large in the central portion of the microlens, The second lens curved surface having a relatively small area can be easily formed near the periphery. That is, it is possible to easily manufacture a microlens having a plurality of second lens curved surfaces near the periphery of the first lens curved surface.

  The electro-optical device of the present invention includes the microlens array plate of the present invention described above in order to solve the above problems.

  According to the electro-optical device of the present invention, like the microlens array plate of the present invention, the light condensing property to the pixels can be improved, and an electro-optical device excellent in display performance can be provided. In addition, since the electro-optical device of the present invention includes the microlens array plate as described above, the light use efficiency can be increased, and the light condensing property and contrast for each pixel can be improved. It is. Therefore, the electro-optical device of the present invention can perform high-quality display that is bright and has a high contrast ratio.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention.

  According to the electronic apparatus of the present invention, since the electro-optical device of the present invention described above is provided, a projection display device, a liquid crystal television, a mobile phone, an electronic notebook, a word processor, a viewfinder capable of high-quality display. Various electronic devices such as a video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized. In addition to electrophoretic devices such as electronic paper, for example, electronic devices of the present invention include display devices using electron-emitting devices (Field Emission Display and Surface-Conduction Electron-Emitter Display), DLP (Digital Light Processing), etc. Can also be realized.

  In order to solve the above-described problem, a method for manufacturing a microlens array plate of the present invention includes a first portion corresponding to a first lens curved surface included in each of a plurality of microlenses to be formed on a transparent substrate, and the first portion. A plurality of first openings that are respectively located in the vicinity of one location and opened at a plurality of second locations corresponding to a plurality of second lens curved surfaces of each of the plurality of microlenses to be formed. A step of forming a first mask, a step of forming a second mask precursor having an etching rate higher than that of the first mask on the first mask with respect to a predetermined type of etchant, and the second mask precursor Forming a second mask by performing etching with the predetermined type of etchant to form a second opening that is opened in a region including the first portion; and Etching the transparent substrate through the first mask and the second mask to partially form a first recess that defines the curved surface of the first lens, and for the second mask The step of removing the second mask by performing etching with the predetermined type of etchant, and the step of forming the first recess by performing etching on the transparent substrate through the first mask. Forming a plurality of second recesses that respectively define the plurality of second lens curved surfaces.

  According to the method for manufacturing a microlens array plate of the present invention, first, on a transparent substrate such as a quartz substrate or a glass substrate, for example, by CVD (Chemical Vapor Deposition) or the like, for example, amorphous silicon (a-Si), polysilicon A film made of (poly-Si) or the like is formed. Next, a first portion corresponding to the first lens curved surface of each of the plurality of microlenses to be formed and a plurality of second lenses to be formed around the first portion with respect to the film. Each of the plurality of second portions corresponding to the curved surface is etched to open the plurality of first openings and form a first mask.

  Next, on the first mask, for example, a second mask precursor made of, for example, chromium (Cr) having a higher etching rate for a predetermined type of etchant such as ceric ammonium nitrate than the first mask is formed by, for example, sputtering. Form. Here, the “precursor” according to the present invention means what becomes the second mask by opening the first opening, and the material thereof is the material of the second mask itself.

  Next, the second mask precursor is etched with the above-described predetermined type of etchant, thereby opening a second opening in a region including the first portion and forming a second mask. At this time, the etching rate for the above-mentioned predetermined type of etchant is higher for the second mask precursor than for the first mask, so that the first mask is hardly or not etched at all.

  Next, the first concave portion defining the first lens curved surface is partially formed by etching the transparent substrate through the first mask and the second mask.

  Next, the second mask is removed by etching the second mask with the above-described predetermined type of etchant.

  Next, the transparent substrate is etched through the first mask to form a first recess and a plurality of second recesses that respectively define a plurality of second lens curved surfaces. The first mask may then be removed using, for example, an organic alkaline stripping solution.

  Thereafter, the microlens array plate can be manufactured by filling the first concave portion and the second concave portion with a transparent medium, or using the concave portion as a mold. Further, a microlens array plate of a biconvex lens can be manufactured by preparing two substrates on which such microlenses are formed and bonding them together.

  As a result, according to the microlens array plate manufacturing method of the present invention, the above-described macro lens array plate of the present invention can be manufactured. In particular, since two types of masks, a first mask and a second mask, are used, it can be manufactured relatively easily. The microlens array plate manufactured in this way can be suitably used for an electro-optical device in which pixels are arranged in an array or a matrix, for example, and the display luminance for each pixel can be increased uniformly.

  In one aspect of the method for manufacturing a microlens array plate of the present invention, the thickness of the first mask is thinner than the thickness of the second mask.

  According to this aspect, since the thickness of the first mask is thinner than the thickness of the second mask, when removing the second mask from the second mask that has entered the first opening formed in the first mask. In addition, it can easily be removed almost or preferably completely. For this reason, when etching is performed through the first mask after the second mask is removed, the etching cannot be sufficiently performed due to a part of the second mask remaining in the first opening or uniform between the plurality of microlenses. Can be prevented. Therefore, the quality of the microlens array plate can be improved. Furthermore, the yield in manufacturing the microlens array plate is also improved.

  The manufacturing method of the electro-optical device of the present invention includes the above-described manufacturing method of the microlens array plate of the present invention.

  According to the method for manufacturing the electro-optical device of the present invention, since the method for manufacturing the microlens array plate of the present invention described above is included, the microlens array plate of the present invention described above and the electro-optical device of the present invention described above are relatively compared. Easy to manufacture.

According to the substrate etching method of the present invention, a step of forming a first mask having a plurality of first openings on the substrate, and an etching rate for a predetermined type of etchant on the first mask is higher than that of the first mask. Forming a higher second mask precursor, and etching the second mask precursor with the predetermined type of etchant to provide a portion corresponding to at least one of the plurality of first openings. Forming a second opening that is opened in a region to include, and forming a second mask; and etching the substrate through the first mask and the second mask to thereby form a first recess. A step of removing the second mask by etching the second mask with the predetermined type of etchant;
Etching the substrate through the first mask forms a first recess and forms second recesses at locations corresponding to the plurality of first openings excluding locations corresponding to the first recesses. Forming.

  According to the substrate etching method of the present invention, first, a first mask having a plurality of first openings is formed on the substrate. Next, a second mask precursor having an etching rate for a predetermined type of etchant higher than that of the first mask is formed on the first mask by, for example, sputtering.

  Next, the second mask precursor is etched with a predetermined type of etchant to form a second opening that is opened in a region including a portion corresponding to at least one of the plurality of first openings. Then, a second mask is formed. At this time, since the etching rate for the predetermined type of etchant is higher for the second mask precursor than for the first mask, the first mask is hardly or not etched at all.

  Next, the first recess is partially formed by etching the substrate through the first mask and the second mask.

  Next, the second mask is removed by etching the second mask with the above-described predetermined type of etchant.

  Next, the substrate is etched through a first mask to form a first recess and a second recess at a location corresponding to the plurality of first openings excluding a location corresponding to the first recess. Form. At this time, etching is simultaneously performed once on a portion where the first concave portion is partially formed and a portion where etching is not yet performed. Therefore, the recessed part (namely, 1st recessed part and 2nd recessed part) which has two types of different curved surfaces can be formed.

  Thereafter, for example, by using the curved surface defined by the concave portion, it is possible to manufacture a microlens array having two different lens curved surfaces relatively easily.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
(Configuration of micro lens array plate)
First, an outline of the microlens array plate of the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view showing a schematic configuration of a microlens array plate. FIG. 2 is an enlarged partial plan view showing an enlarged portion related to four adjacent microlenses among the microlenses provided in the microlens array plate. 3 is a cross-sectional view taken along line AA ′ of FIG.

  In FIG. 1, the microlens array plate 20 of the present embodiment includes a transparent substrate 210 and a plurality of microlenses 500 arranged in a plane on the transparent substrate 210 in a matrix. The transparent substrate 210 is, for example, a quartz plate or the like, and a large number of recesses are formed in a matrix. The concave portion dug in the transparent substrate 210 is filled with, for example, an adhesive made of a photosensitive resin material. The adhesive layer 230 is formed by curing the adhesive, and the cover glass 200 and the transparent substrate 210 disposed so as to cover the transparent substrate 210 are bonded to each other. The adhesive that bonds the cover glass 200 and the transparent substrate 210 is, for example, a transparent adhesive layer having a higher refractive index than that of the transparent substrate 210. Here, the transparent substrate 210 is an example of the “first transparent medium” according to the present invention, and the adhesive layer 230 is an example of the “second transparent medium” according to the present invention.

  Next, the planar shape of the microlens 500 will be described. As shown in FIG. 2, the planar shape of each microlens 500 is preferably rectangular. The planar shape of each microlens 500 is defined by the edge of the recess. The concave portion in which one microlens 500 shown in FIG. 2 is formed is adjacent to the concave portion in which another microlens 500 is formed, sharing an edge.

  2 and 3, the lens curved surface of the microlens 500 is generally defined by the transparent substrate 210 and the adhesive layer 230 having different refractive indexes. The microlens 500 is constructed as a so-called plano-convex lens having a condensing function, which protrudes in a convex shape substantially downward in FIG.

(Configuration of micro lens)
Next, the configuration of the microlens applied to the microlens array plate will be described in detail with reference to FIGS. FIG. 4 is a plan view of the microlens as seen from above. FIG. 5 is a schematic diagram schematically showing a cross-sectional shape of a microlens corresponding to a cross section taken along line TT ′ of FIG. FIG. 6 is a schematic diagram having the same concept as in FIG. 5 in the comparative example. FIG. 7 is a plan view having the same concept as in FIG. 4 in the first modification. FIG. 8 is a plan view having the same concept as in FIG. 4 in the second modification.

  As shown in FIGS. 4 and 5, the microlens 500 includes a first portion 510 that defines the first lens curved surface CS <b> 1 at the center when viewed in plan on the microlens array plate 20. Four second portions 520 that respectively define the second lens curved surface CS2 are provided near the periphery. The first portion 510 and the four second portions 520 are integrally formed from the transparent substrate 210 and have any concave shape. The first lens curved surface CS1 and the second lens curved surface CS2 are smoothly connected, but there may be some steps or discontinuities.

  As shown in FIG. 4, the first portion 510 is formed so as to occupy a wider area than the one second portion 520 when viewed in plan on the microlens array plate 20. In other words, the first portion 510 is formed to function as a main lens, and the second portion 520 is configured to function as an auxiliary subordinate lens. Here, in FIG. 4, a point C1 indicates a lens center where the first portion 510 functions as a lens, and four points C2 indicate a lens center where each of the four second portions 520 functions as a lens. Yes.

  As shown in FIG. 6, if each of the microlenses 500 includes only the first portion 510 that defines the first lens curved surface CS <b> 1, the first curved surface defined by the first portion 510 in the peripheral portion of the microlens 500. An angle Θ20 formed by a plane that is in contact with the sphere S1 that forms CS1 and the microlens array plate 20 (that is, the flat surface of the transparent substrate 210) is a plane that is in contact with the sphere S1 that forms the first lens curved surface CS1 at the center of the microlens 500. The angle is larger than the angle formed with the microlens array plate 20 (that is, the flat surface of the transparent substrate 210). For this reason, the condensing property of the microlens 500 with respect to the light incident on the microlens array plate 20 is lower in the peripheral portion of the microlens 500 than in the central portion. Alternatively, since the peripheral portion of the microlens 500 has a surface that is excessively inclined with respect to the incident light, the microlens 500 does not function properly as a lens or cannot condense properly toward the central portion.

  However, as shown in FIG. 5, according to the microlens array plate 20 of the present embodiment, a plurality of second curved surfaces CS2 are positioned closer to the periphery of the first lens curved surface CS1. Each of the microlenses has only the first portion 510 at an angle Θ10 formed by the lens curved surface in FIG. 1, that is, the plane contacting the sphere S2 forming the second curved surface CS2 and the surface of the transparent substrate 210 (that is, the microlens array plate 20). It can be made smaller than the case. In other words, the lens curved surface in the peripheral portion of the microlens 500 can be made gentle or close to the microlens array plate 20. Therefore, the light incident on the peripheral portion of the microlens 500 can be appropriately condensed. That is, for example, the light can be efficiently condensed on each of a plurality of pixels arranged in the pixel array region of the electro-optical panel arranged to face each other through a liquid crystal layer having a predetermined refractive index.

  In addition, since each of the microlenses 500 can further include not only the first portion 510 but also the four second portions 520 as design parameters, the degree of freedom in design is high and the light condensing property is further improved. It is possible to design.

  In the present embodiment, the first portion 510 and the four second portions 520 of the microlens 500 are filled with the adhesive layer 230 having a higher refractive index than the refractive index of the transparent substrate 210 that integrally forms them. Therefore, the function of each of the plurality of microlenses 500 as a lens is the magnitude relationship between the refractive index of the adhesive layer 230 and the refractive index of the transparent substrate 210 in addition to the unevenness of the first lens curved surface CS1 and the second lens curved surface CS2. Will depend on. Here, the refractive index of the transparent substrate 210 is an example of the “first refractive index” according to the present invention, and the refractive index of the adhesive layer 230 is an example of the “second refractive index” according to the present invention. For this reason, the degree of freedom in design is high, and it is possible to design so as to further improve the light collecting property by combining the refractive indexes of the adhesive layer 230 and the transparent substrate 210.

  As shown in FIG. 5, in this embodiment, the refractive index of the adhesive layer 230 is designed to be larger than the refractive index of the transparent substrate 210, and the plurality of microlenses 500 are configured as convex lenses having a condensing function. ing.

  As shown in FIGS. 4 and 5, in the present embodiment, the center of the sphere S <b> 1 that forms the first lens curved surface CS <b> 1 is viewed in plan on the microlens array plate 20, and each of the plurality of microlenses 500. It is located at the center (see point C1 in FIG. 4). For this reason, the light incident on the center of each of the plurality of microlenses 500 is collected by the first portion 510 that defines the first lens curved surface CS1. Since the first lens curved surface CS1 has a gentle curvature with respect to the surface of the microlens array substrate 20 at the center of the microlens 500, it can be condensed efficiently.

  Further, as shown in FIGS. 4 and 5, in the present embodiment, the center of the sphere S2 forming the second lens curved surface CS2 is viewed on the microlens array plate 20 in plan view, and the first lens curved surface CS1. (See point C2 in FIG. 4). For this reason, the light incident on the positions of the plurality of microlenses 500 that are out of the vicinity of the first lens curved surface CS1 is collected by the second portion 520 that defines the second lens curved surface CS2. Here, the centers of the spheres S2 forming the second lens curved surface CS2 are located on the microlens array plate 20 so as to deviate from the center of the spheres S1 forming the first lens curved surface CS1 when viewed in plan. Therefore, since the second curved surface CS2 is almost parallel to the surface of the microlens array substrate 20 in the peripheral portion of the microlens 500, it can be efficiently condensed.

  In addition, as shown in FIGS. 4 and 5, in the present embodiment, in particular, the second lens curved surface CS <b> 2 occupies each corner of the plurality of microlenses 500. That is, four second lens curved surfaces CS2 are provided for one microlens 500, and four corners of one microlens 500 are respectively occupied by the second lens curved surface CS2. In this case, since the second lens curved surface CS2 is almost parallel or gentle to the surface of the microlens array substrate 20 at the four corners of the microlens 500, the second lens curved surface CS2 can be efficiently condensed. That is, the light incident on the four corners of the microlens can be reliably condensed by the second lens curved surface CS2.

  As shown in FIG. 7 as a first modification, the second lens curved surface CS2 may be formed so as to occupy two corners positioned diagonally among the four corners of one microlens. Also in this case, compared with the case where only the first lens curved surface 510 is provided, the lens curved surface in the peripheral portion of the microlens 500 can be made gentle with respect to the microlens array plate 20, and the light can be collected efficiently. Can do.

  Alternatively, as shown in FIG. 8 as a second modification, the second lens curved surface CS2 may be formed so as to occupy the central part of the four sides of one microlens. Also in this case, the lens curved surface in the periphery of the micro lens 500 can be made gentle with respect to the micro lens array plate 20, and the light can be collected more efficiently than the case where only the first lens curved surface 510 is provided. Can do.

In addition, as shown in FIGS. 4 and 5, in this embodiment, in particular, the radius of curvature R2 of the second lens curved surface CS2 is smaller than the radius of curvature R1 of the first lens curved surface CS1. Therefore, the first lens curved surface CS1 can be formed relatively large at the center of the microlens 500, and the second lens curved surface CS2 having a relatively small area can be easily formed near the periphery thereof. That is, a microlens having a plurality of second lens curved surfaces CS2 near the periphery of the first lens curved surface CS2 can be easily manufactured.
(Manufacturing method of micro lens array plate)
Next, a method for manufacturing the microlens array plate according to the present embodiment will be described with reference to FIGS. 9 and 10 are process diagrams schematically showing the cross-sectional structure of the microarray plate in the manufacturing process of the microlens array plate of this embodiment in order. It is process sectional drawing which shows each process of a method. FIG. 11 is a plan view showing the planar shapes of the first mask and the second mask according to the present embodiment.

  First, as shown in FIG. 9A, on a transparent substrate 110 made of a quartz substrate, a glass substrate, or the like, amorphous silicon (a-Si), polysilicon (poly-Si) is formed by CVD (Chemical Vapor Deposition) or the like. A film 111a made of or the like is formed.

  Next, as shown in FIG. 9B, a first portion 141a corresponding to the first lens curved surface CS1 of each of the plurality of microlenses to be formed on the film 111a (see FIG. 11A). ) And a plurality of second locations 141b (see FIG. 11A) corresponding to the plurality of second lens curved surfaces CS2 to be formed, respectively, thereby opening the plurality of first openings 141, A first mask 111 is formed. In FIG. 11, the broken line 510eCS1e indicates the outline of the portion where the first lens curved surface CS1 is to be formed, and the broken line 520eCS2e is the portion where the second lens curved surface CS2 is to be formed. The outline is shown.

  Next, as shown in FIG. 9C, a second mask precursor 112a made of chromium (Cr) or the like is formed on the first mask 111 by sputtering or the like.

  Next, as shown in FIG. 9D, the second mask precursor 112a is etched using ceric ammonium nitrate or the like as an etchant, so that a second opening is formed in a region including the first portion 141a. 142 is opened, and a second mask 112 is formed. At this time, the etching rate for the etchant such as ceric ammonium nitrate is a second mask made of chromium (Cr) or the like rather than the first mask 111 made of amorphous silicon (a-Si), polysilicon (poly-Si) or the like. Since it is higher than the precursor 112a, the first mask 111 is hardly or not etched at all.

  Next, as shown in FIG. 10A, the transparent substrate 110 is etched through the first mask 111 and the second mask 112 so that the first concave portion that defines the first lens curved surface CS1 is partially formed. (In FIG. 10A, reference numeral 151a).

  Next, as shown in FIG. 10B, the second mask 111 is removed by etching the second mask 111 using ceric ammonium nitrate or the like as an etchant.

  Here, in particular, in the present embodiment, the thickness of the first mask 111 is thinner than the thickness of the second mask 112, so the second mask 112 entering the first opening 141 opened in the first mask 111 is When the second mask 112 is removed, it is easily or preferably completely removed. For this reason, as will be described later, when etching is performed through the first mask 111, the etching cannot be sufficiently performed due to a portion of the second mask 112 remaining in the first opening 141, or evenly between a plurality of microlenses. It can be prevented that it becomes impossible.

  Next, as shown in FIG. 10 (c), the transparent substrate 110 is etched through the first mask 111, and a plurality of first concave portions 151 and a plurality of second lens curved surfaces CS2 are defined. Two recesses 152 are formed.

  Next, as shown in FIG. 10D, the first mask 111 is removed using, for example, an organic alkaline stripping solution or the like.

  Thereafter, the microlens array plate can be manufactured by filling the first concave portion 151 and the second concave portion 152 with a transparent medium or using the concave portion as a mold. Further, a microlens array plate of a biconvex lens can be manufactured by preparing two substrates on which such microlenses are formed and bonding them together.

As a result, the macro lens array plate 20 of the present embodiment described above can be manufactured. In particular, since two types of masks, the first mask 111 and the second mask 112, are used, they can be manufactured relatively easily. The microlens array plate 20 manufactured in this way can be suitably used for, for example, an electro-optical device in which pixels are arranged in an array or matrix, and the display luminance for each pixel can be increased uniformly.
(Electro-optical device)
Next, an electro-optical device to which the microlens array plate according to the present invention is applied will be described with reference to FIGS. 12 is a plan view of the TFT array substrate as viewed from the side of the microlens array plate used as a counter substrate together with each component formed thereon, and FIG. 13 is a cross-sectional view taken along the line HH ′ of FIG. is there. Here, a TFT active matrix driving type liquid crystal device with a built-in driving circuit, which is an example of an electro-optical device, is taken as an example.

  12 and 13, in the liquid crystal device 80, the TFT array substrate 10 and the microlens array plate 20 used as a counter substrate are disposed to face each other. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the microlens array plate 20, and the TFT array substrate 10 and the microlens array plate 20 are provided in a seal region positioned around the image display region 10a. They are bonded to each other by a sealing material 52.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. Further, a gap material such as glass fiber or glass bead is dispersed in the sealing material 52 to set the distance between the TFT array substrate 10 and the microlens array plate 20 (inter-substrate gap) to a predetermined value. That is, the electro-optical device according to the present embodiment is suitable for a small and enlarged display for a projector light valve.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display region 10a is provided on the microlens array plate 20 side in parallel with the inside of the seal region where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  Of the peripheral regions located around the image display region 10 a, the data line driving circuit 101 and the external circuit connection terminal 102 are arranged on one side of the TFT array substrate 10 in the region located outside the seal region where the sealing material 52 is disposed. It is provided along. The scanning line driving circuit 104 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 53. Further, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display area 10a in this way, the TFT array substrate 10 is covered with the frame light shielding film 53 along the remaining side. A plurality of wirings 105 are provided.

  In addition, at the four corners of the microlens array plate 20, vertical conductive members 106 functioning as vertical conductive terminals between the two substrates are disposed. On the other hand, the TFT array substrate 10 is provided with vertical conduction terminals in a region facing these corner portions. As a result, electrical conduction can be established between the TFT array substrate 10 and the microlens array plate 20.

  In FIG. 13, on the TFT array substrate 10, an alignment film is formed on the pixel electrode 9a after the pixel switching TFT, the scanning line, the data line and the like are formed. On the other hand, although a detailed configuration will be described later, on the microlens array plate 20, in addition to the counter electrode 21, a lattice-shaped or striped light-shielding film 23 and an alignment film are formed in the uppermost layer portion. Further, the liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films.

  In addition to the data line driving circuit 101, the scanning line driving circuit 104, etc., the image signal on the image signal line is sampled and supplied to the data line on the TFT array substrate 10 shown in FIGS. Sampling circuit, precharge circuit for supplying a precharge signal of a predetermined voltage level to a plurality of data lines in advance of an image signal, for inspecting the quality, defects, etc. of the electro-optical device during production or at the time of shipment An inspection circuit or the like may be formed.

  Next, the circuit configuration and operation of the electro-optical device configured as described above will be described with reference to FIG. FIG. 14 is a circuit diagram illustrating an equivalent circuit of various elements, wirings, and the like in a plurality of pixels formed in a matrix that forms an image display region of the electro-optical device.

  In FIG. 14, a pixel electrode 9a and a TFT 30 for controlling the switching of the pixel electrode 9a are formed in each of the plurality of pixels formed in a matrix constituting the image display region 10a of the liquid crystal device 80. The data line 6a to which the image signal is supplied is electrically connected to the source of the TFT 30. The image signals S1, S2,..., Sn written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. Good.

  Further, the gate electrode 3a is electrically connected to the gate of the TFT 30, and the scanning signals G1, G2,..., Gm are pulse-sequentially applied in this order to the scanning line 11a and the gate electrode 3a at a predetermined timing. It is comprised so that it may apply. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the image signal S1, S2,..., Sn supplied from the data line 6a is obtained by closing the switch of the TFT 30 as a switching element for a certain period. Write at a predetermined timing.

  A predetermined level of the image signals S1, S2,..., Sn written in the liquid crystal as an example of the electro-optical material via the pixel electrode 9a is between the counter electrode 21 formed on the microlens array plate 20 for a certain period. Retained. The liquid crystal modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel, and in the normally black mode, the light is incident according to the voltage applied in units of each pixel. The light transmittance is increased, and light having a contrast corresponding to the image signal is emitted from the electro-optical device as a whole.

  In order to prevent the image signal held here from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode. The storage capacitor 70 is provided side by side along the scanning line 11a, and includes a capacitor electrode 300 including a fixed potential side capacitor electrode and fixed at a constant potential.

  Next, the detailed configuration and function of the microlens array plate 20 provided in the liquid crystal device 80 described above will be described with reference to FIGS. 15 and 16. FIG. 15 is a plan view schematically showing the arrangement relationship between the light shielding film 23 and the microlens 500 in the microlens array plate 20, and FIG. 16 shows the configuration of the cross section shown in FIG. It is a figure shown in detail, Comprising: It is sectional drawing for demonstrating the function of each micro lens 500. FIG.

  In FIG. 16, in the microlens array plate 20, a light shielding film 23 having a lattice-like planar pattern as shown in FIG. 15 is formed on a transparent substrate 210. In the microlens array plate 20, a non-opening area is defined by the light shielding film 23, and an area delimited by the light shielding film 23 is an opening area 700. The light shielding film 23 is formed in a stripe shape, and the non-opening region is defined by the light shielding film 23 and various components such as the capacitor electrode 300 and the data line 6a provided on the TFT array substrate 10 side. Also good.

  Each microlens 500 is arranged so as to correspond to each pixel. More specifically, as shown in FIG. 15, in the microlens array plate 20, each pixel has a rectangular shape in an area including at least a part of the opening area 700 and the non-opening area located around the opening area 700. A microlens 500 having a planar shape is formed.

  In FIG. 16, the counter electrode 21 made of a transparent conductive film is formed on the transparent substrate 210 so as to cover the light shielding film 23. Further, an alignment film (not shown in FIG. 16) is formed on the counter electrode 21. In addition, a color filter may be formed in each opening region 700 on the transparent substrate 210.

  On the other hand, in FIG. 16, pixel electrodes 9 a are formed in regions corresponding to the respective opening regions 700 on the TFT array substrate 10. In addition, the pixel switching TFT 30, the various wirings such as the scanning line 11a and the data line 6a for driving the pixel electrode 9a, and the electronic elements such as the storage capacitor 70 are formed in the non-opening region. With this configuration, the pixel aperture ratio in the liquid crystal device 80 can be maintained relatively large. Further, although not shown in FIG. 16, an alignment film is provided on the pixel electrode 9a.

  In FIG. 16, light such as projection light incident on the microlens array plate 20 is collected by each microlens 500. In addition, in FIG. 16, the mode of the light condensed by the micro lens 500 by the dashed-dotted line is shown schematically. Then, the light collected by each microlens 500 is transmitted through the liquid crystal layer 50 and irradiated onto the pixel electrode 9a, passes through the pixel electrode 9a, and is emitted from the TFT array substrate 10 as display light. Here, in this embodiment, in particular, the lens curved surface of the microlens 500 includes the first lens curved surface CS1 and the four second lens curved surfaces CS2 closer to the periphery thereof as described above. The curved surface of the lens is gentle with respect to the microlens array plate 210. Therefore, the light traveling toward the non-opening region among the light incident on the microlens array plate 20 can also be efficiently incident on the opening region 700 by the condensing action of the microlens 500, and the light use efficiency can be improved. It is also possible to improve the light collecting property and contrast for each pixel. Therefore, the liquid crystal device 80, which is an example according to the present embodiment, can perform high-quality display that is bright and has a high contrast ratio.

  In the liquid crystal device 80, which is an example of the electro-optical device according to the present embodiment described above, instead of providing the data line driving circuit 101 and the scanning line driving circuit 104 on the TFT array substrate 10, for example, TAB (Tape Automated Bonding) The driving LSI mounted on the substrate may be electrically and mechanically connected to the external circuit connection terminal 102 via an anisotropic conductive film. Further, for example, a TN (Twisted Nematic) mode, a VA (Vertical Aligned) mode, and a PDLC (Polymer Dispersed) are respectively provided on the side on which the projection light of the microlens array plate 20 is incident and on the side on which the emission light of the TFT array substrate 10 is emitted. A polarizing film, a retardation film, a polarizing plate, and the like may be arranged in a predetermined direction according to an operation mode such as a liquid crystal mode or a normally white mode / normally black mode.

  In the electro-optical device described above, the microlens array plate 20 as shown in FIGS. 1 to 5 is used as the counter substrate. However, such a microlens array plate 20 is used as the TFT array substrate 10. Is also possible. Alternatively, it is possible to attach the microlens array substrate 20 to the TFT array substrate 10 side by simply using a glass substrate or the like on which the counter electrode or alignment film is formed as the counter substrate (not the microlens array plate 20). It is. That is, the microlens of the present invention can be built or attached to the TFT array substrate 10 side.

  FIG. 16 shows a configuration in which a curved surface in which each microlens 500 protrudes in the electro-optical device is arranged facing downward in the figure. As shown in FIG. You may make it arrange | position the curved surface which protruded the lens 500 convexly toward the upper side in the figure. FIG. 17 is a cross-sectional view similar to FIG. 16, showing the configuration of the microlens 500 in this case. In FIG. 17, the light shielding film 23 and the like are formed on the cover glass 200 in the same manner as in FIG.

(Electronics)
An overall configuration, particularly an optical configuration, of an embodiment of a projection color display device as an example of an electronic apparatus using the electro-optical device described above as a light valve will be described. FIG. 18 is a schematic cross-sectional view of the projection type color display device.

  In FIG. 18, a liquid crystal projector 1100, which is an example of a projection type color display device, prepares three liquid crystal modules including a liquid crystal device having a drive circuit mounted on a TFT array substrate, and RGB light valves 100R, 100G, and The projector is configured as 100B. In the liquid crystal projector 1100, when projection light is emitted from a lamp unit 1102 of a white light source such as a metal halide lamp, light components R, G, and R corresponding to the three primary colors of RGB are obtained by three mirrors 1106 and two dichroic mirrors 1108. The light is divided into B and led to the light valves 100R, 100G and 100B corresponding to the respective colors. In particular, the B light is guided through a relay lens system 1121 including an incident lens 1122, a relay lens 1123, and an exit lens 1124 in order to prevent light loss due to a long optical path. Light components corresponding to the three primary colors modulated by the light valves 100R, 100G, and 100B are synthesized again by the dichroic prism 1112 and then projected as a color image on the screen via the projection lens 1114.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and a microlens array plate with such a change Also, a method for manufacturing the microarray plate, an electro-optical device including the microarray plate, a method for manufacturing the electro-optical device, an electronic apparatus including the electro-optical device, and a method for etching a substrate are also included in the technical scope of the present invention. It is included in the range.

It is the perspective view which showed schematic structure of the micro lens array board which concerns on 1st Embodiment. It is the elements on larger scale which the micro lens array board concerning a 1st embodiment shows a part enlarged. FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2. It is the top view which looked at the micro lens concerning a 1st embodiment from the upper part. It is a schematic diagram which shows typically the cross-sectional shape of the micro lens which concerns on 1st Embodiment. It is a schematic diagram with the same meaning as FIG. 5 in a comparative example. It is a top view of the same meaning as FIG. 4 in a 1st modification. It is a top view of the same meaning as FIG. 4 in a 2nd modification. It is manufacturing process sectional drawing (the 1) which shows the manufacturing method of the micro lens array board which concerns on 1st Embodiment later on. FIG. 6 is a manufacturing process cross-sectional view (part 2) illustrating the manufacturing method of the microlens array plate according to the first embodiment in order. It is a top view which shows the planar shape of the 1st mask and 2nd mask which concern on 1st Embodiment. It is the top view which looked at the TFT array board | substrate from the micro lens array board side used as an opposing board | substrate with each component formed on it. It is H-H 'sectional drawing of FIG. FIG. 3 is a circuit diagram illustrating an equivalent circuit of various elements, wirings, and the like in a plurality of pixels formed in a matrix that forms an image display region of the electro-optical device. It is a top view which shows typically the arrangement | positioning relationship of the light shielding film and microlens in the microlens array board concerning 1st Embodiment. It is sectional drawing which showed the structure of the cross section shown in FIG. 13 in detail. It is sectional drawing for demonstrating arrangement | positioning of each micro lens. It is sectional drawing which shows an example of the electronic device which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Micro lens array board, 110, 210 ... Transparent substrate, 111 ... 1st mask, 112 ... 2nd mask, 230 ... Adhesion layer, 500 ... Micro lens, 510 ... 1st part, 520 ... 2nd part, CS1 ... 1st lens curved surface, CS2 ... 2nd lens curved surface

Claims (12)

A microlens array plate in which a plurality of microlenses are arranged on a transparent substrate,
Each of the plurality of microlenses is
A first portion made of a first transparent medium having a first refractive index, defining a first lens curved surface and having a concave or convex shape;
A second lens curved surface is formed integrally with the first portion from the first transparent medium and located near the periphery of the first lens curved surface when viewed in plan on the microlens array plate. And a plurality of second portions each having one of a concave shape and a convex shape that are the same type as the one shape.   Each of the plurality of microlenses further includes a second transparent medium having a second refractive index different from the first refractive index and filling or covering the first portion and the plurality of second portions. The microlens array plate according to claim 1.   The center of the sphere forming the first lens curved surface is located at the center of each of the plurality of microlenses when viewed in plan on the microlens array plate. Micro lens array plate.   The centers of the spheres forming the second lens curved surface are located on the microlens array plate so as to be out of the vicinity of the periphery from the centers of the spheres forming the first lens curved surface, respectively. The microlens array plate according to any one of claims 1 to 3.   5. The microlens array plate according to claim 1, wherein each of the second lens curved surfaces occupies a corner of each of the plurality of microlenses. 6.   The microlens array plate according to any one of claims 1 to 5, wherein a radius of curvature of the second lens curved surface is smaller than a radius of curvature of the first lens curved surface.   An electro-optical device comprising the microlens array plate according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 7. On a transparent substrate
A first location corresponding to the first lens curved surface of each of the plurality of microlenses to be formed, and a plurality of first lenses located in the periphery of the first location and each of the plurality of microlenses to be formed have. Forming a first mask having a plurality of first openings respectively opened at a plurality of second locations corresponding to the two-lens curved surface;
Forming a second mask precursor on the first mask having a higher etching rate for a predetermined type of etchant than the first mask;
Etching the second mask precursor with the predetermined type of etchant to form a second opening opened in a region including the first location, and forming a second mask; ,
Etching the transparent substrate through the first mask and the second mask to partially form a first recess that defines the first lens curved surface;
Removing the second mask by etching the second mask with the predetermined type of etchant;
Etching the transparent substrate through the first mask to form the first recesses and forming a plurality of second recesses that respectively define the plurality of second lens curved surfaces. A method of manufacturing a microlens array plate characterized by the above.   The method of manufacturing a microlens array plate according to claim 9, wherein the thickness of the first mask is thinner than the thickness of the second mask.   A method for manufacturing an electro-optical device, comprising the method for manufacturing a microlens array plate according to claim 9. On the board
Forming a first mask having a plurality of first openings;
Forming a second mask precursor on the first mask having a higher etching rate for a predetermined type of etchant than the first mask;
Etching the second mask precursor with the predetermined type of etchant forms a second opening that is opened in a region including a portion corresponding to at least one of the plurality of first openings. Forming a second mask;
Etching the substrate through the first mask and the second mask to partially form a first recess;
Removing the second mask by etching the second mask with the predetermined type of etchant;
Etching the substrate through the first mask to form a first recess and forming a plurality of second recesses. A method for etching a substrate, comprising:

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