JP2014102311A - Microlens array substrate, method for manufacturing microlens array substrate, electro-optic device, and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microlens array substrate in which reflectance on a lens surface is reduced and incident light can be efficiently condensed, and to provide a method for manufacturing the microlens array substrate, and an electro-optic device and electronic equipment including the microlens array substrate.SOLUTION: A microlens array substrate 25A includes: a substrate body 21 as a transparent substrate having a plurality of concave lens surfaces 23 on a surface 21a as a first surface; and a lens layer 22A which is formed to fill the lens surfaces 23 and has a refractive index different from that of the substrate body 21. In the microlens array substrate, a minute three-dimensional structure comprising a plurality of minute recesses 31 is formed on at least the lens surface 23 where the lens layer 22A is in contact with.

Description

  The present invention relates to a microlens array substrate, a method for manufacturing the microlens array substrate, an electro-optical device including the microlens array substrate, and an electronic apparatus.

As the microlens array substrate, for example, in Patent Document 1, a lens forming substrate having a plurality of microlenses, an antireflection forming layer stacked on the lens forming substrate, and a layer in contact with the antireflection forming layer are stacked. A microlens substrate including an adjacent layer having a large refractive index difference from the antireflection forming layer is disclosed. Further, in Patent Document 1, the antireflection forming layer is formed on the surface in contact with the adjacent layer so that the cross-sectional area when the surface is cut in a plane parallel to the surface direction of the microlens substrate gradually changes. It is shown having a plurality of fine protrusions. It is said that reflection of light incident on a surface on which a plurality of fine protrusions are formed can be suppressed.
A structure capable of suppressing the reflection of light by providing such a plurality of fine convex portions is called a moth-eye structure. “Moseye” is a registered trademark of Dai Nippon Printing Co., Ltd.

  For example, Patent Document 2 includes a lens array having a plurality of lens portions and a counter substrate provided at a position facing the lens portions, and a micro three-dimensional structure between the plurality of lens portions and the counter substrate. An optical element provided with an antireflection layer made of is disclosed. It is shown that the micro three-dimensional structure is a moth-eye structure composed of fine particle aggregates. Then, there is a method in which a coating material in which fine particles are dispersed in a solvent is applied to the surface of the optical element, and the fine particles are aggregated by evaporating the solvent to form an antireflection layer comprising a moth-eye structure on the surface of the optical element. It is shown. According to Patent Document 2, when light transmitted through the lens unit is incident on the counter substrate, it can be prevented from being reflected at the interface between the lens unit and the counter substrate.

JP 2010-181791 A JP 2007-264066 A

  In Patent Document 1, since the moth-eye structure is not introduced on the lens surface of the microlens, light incident on the lens surface may be reflected. In that respect, in the optical element of Patent Document 2, a moth-eye structure composed of fine particle aggregates is also introduced into the lens surface of the lens portion. However, when the antireflection layer forming method of Patent Document 2 is used, if a paint containing fine particles and a solvent is applied to a curved lens surface, the paint has fluidity. In the drying process, coating unevenness tends to occur. That is, there is a problem that it is difficult to form a uniform moth-eye structure on the lens surface.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A microlens array substrate according to this application example is formed by filling a transparent substrate having a plurality of concave lens surfaces on a first surface and the lens surface, and has a refractive index with respect to the transparent substrate. And a small three-dimensional structure is formed on at least the lens surface in contact with the lens layer.

  According to this application example, reflection of light incident on the concave lens surface can be reduced by the minute three-dimensional structure. That is, it is possible to provide a microlens array substrate having at least low light reflection on the lens surface and high light transmission characteristics.

  Application Example 2 A microlens array substrate according to this application example includes a transparent substrate having a plurality of convex lens surfaces on a first surface, and a micro three-dimensional structure is formed on the lens surface. Features.

  According to this application example, reflection of light incident on the convex lens surface can be reduced by the minute three-dimensional structure. That is, it is possible to provide a microlens array substrate having at least low light reflection on the lens surface and high light transmission characteristics.

Application Example 3 The microlens array substrate according to the application example described above includes a lens layer that covers the first surface of the transparent substrate, and the lens surface is formed on the lens layer and covers the lens surface. And a transparent layer having a refractive index smaller than that of the lens layer.
According to this configuration, light incident on the lens surface from the transparent substrate side can be efficiently condensed on the transparent layer side. Further, the lens surface on which the minute three-dimensional structure is formed can be protected by the transparent layer.

Application Example 4 In the microlens array substrate according to the application example described above, the minute three-dimensional structure includes minute recesses.
According to this configuration, for example, a large number of minute recesses can be formed by selectively etching the lens surface, so that a microlens array substrate having high light transmission characteristics can be realized relatively easily. it can.

Application Example 5 In the microlens array substrate according to the application example described above, it is preferable that the minute concave portion is recessed in a substantially normal direction of the first surface of the transparent substrate.
According to this configuration, since the minute recesses are recessed in a certain direction, the reflectance of light reflected in a specific direction can be effectively reduced.

Application Example 6 In the microlens array substrate according to the application example described above, it is preferable that the depth of the minute concave portion becomes deeper from the center portion of the lens surface toward the outer edge portion of the lens surface.
According to this configuration, the incident light along the optical axis of the lens surface has a smaller incident angle as it goes to the outer edge portion and becomes easier to be reflected, but the depth of the minute concave portion becomes deeper as it goes to the outer edge portion. Therefore, reflection of incident light at the outer edge can be reduced.

  Application Example 7 A method for manufacturing a microlens array substrate according to this application example includes a step of forming a plurality of concave lens surfaces on a first surface of a transparent substrate, and a mask having a crystal structure covering at least the lens surfaces. A step of forming a layer, an etching step of performing etching through the mask layer to form a micro three-dimensional structure comprising micro concave portions on the lens surface, a step of removing the mask layer, and the mask layer Filling the lens surface with the lens member removed to form a lens layer.

  Application Example 8 A method for manufacturing a microlens array substrate according to this application example includes a step of forming a plurality of convex lens surfaces on a first surface of a transparent substrate, and a crystal structure covering at least the lens surfaces. A step of forming a mask layer, an etching step of performing etching through the mask layer to form a micro three-dimensional structure composed of micro concave portions on the lens surface, and a step of removing the mask layer. It is characterized by that.

  According to the methods of these application examples, in the etching process, etching is performed through the mask layer having a crystal structure, so that the etching proceeds at the portion of the lens surface corresponding to the gap of the crystal structure. Therefore, a plurality of minute recesses can be formed relatively easily as compared with the case where the lens surface is directly etched to form minute recesses. That is, a bright microlens array substrate can be easily manufactured.

Application Example 9 In the method for manufacturing a microlens array substrate according to the application example, the lens surface is formed on a lens layer covering the first surface of the transparent substrate, and a member having a refractive index smaller than that of the lens layer. And a step of forming a transparent layer covering the lens surface.
According to this method, it is possible to manufacture a microlens array substrate that can efficiently collect light incident on the lens surface from the transparent substrate side on the transparent layer side. Further, it is possible to manufacture a microlens array substrate in which a lens surface on which minute concave portions are formed is protected by a transparent layer.

Application Example 10 In the method of manufacturing a microlens array substrate according to the application example, the mask layer is made of polycrystalline silicon, and the etching process is different from the normal direction of the first surface with respect to the mask layer. Isotropic etching is performed.
According to this method, a plurality of minute recesses recessed in the substantially normal direction of the first surface are formed. By making the formation direction of a plurality of minute recesses constant, it is possible to reflect light incident on the lens surface from various directions compared to the case where minute recesses are formed in a random direction with respect to the lens surface. Can be reduced.

Application Example 11 In the method for manufacturing a microlens array substrate according to the application example, the etching step is performed such that the depth of the minute concave portion increases from the center portion of the lens surface to the outer edge portion of the lens surface. It is preferable to perform anisotropic etching.
The incident angle of light with respect to the lens surface becomes smaller and more easily reflected toward the outer edge, but according to this method, the depth of the minute recess becomes deeper toward the outer edge of the lens surface. The reflection of incident light can be reduced. That is, a brighter microlens array substrate can be manufactured.

Application Example 12 An electro-optical device according to this application example includes the microlens array substrate described in the application example.
According to this configuration, for example, an electro-optical device can be provided as a display device capable of bright display. The electro-optical device is not limited to a display device, and can be applied to an imaging device that requires an optical system.

Application Example 13 An electronic apparatus according to this application example includes the electro-optical device described in the application example.
According to this configuration, it is possible to provide an electronic device capable of bright display.

The schematic plan view which shows arrangement | positioning of the micro lens in the micro lens array board | substrate of 1st Embodiment. (A) is a schematic cross-sectional view of the microlens array substrate along the line AA ′ in FIG. 1, (b) is an enlarged cross-sectional view showing a minute recess in the lens surface, and (c) is a refractive index between the minute recess and the interface FIG. The flowchart which shows the manufacturing method of the micro lens array board | substrate of 1st Embodiment. (A)-(e) is a schematic sectional drawing which shows the manufacturing method of the micro lens array board | substrate of 1st Embodiment. (A) is the electron micrograph which shows the crystal grain boundary of a polycrystalline silicon, (b) is a schematic diagram which shows a micro recessed part. 1 is a schematic plan view illustrating a configuration of a liquid crystal device according to a first embodiment. 1 is a schematic cross-sectional view showing the structure of a liquid crystal device according to a first embodiment. The schematic plan view which shows arrangement | positioning of the micro lens in the micro lens array board | substrate of 2nd Embodiment. (A) is a schematic sectional drawing of the micro lens array board | substrate along the C-C 'line | wire of FIG. 8, (b) is an expanded sectional view which shows the micro recessed part in a lens surface. The flowchart which shows the manufacturing method of the micro lens array board | substrate of 2nd Embodiment. (A)-(d) is a schematic sectional drawing which shows the manufacturing method of the microlens array board | substrate of 2nd Embodiment. (E)-(h) is a schematic sectional drawing which shows the manufacturing method of the microlens array board | substrate of 2nd Embodiment. FIG. 6 is a schematic cross-sectional view illustrating a liquid crystal device as an electro-optical device according to a second embodiment. Schematic which shows the structure of a projection type display apparatus. (A) And (b) is a schematic sectional drawing which shows the structure of the microlens array board | substrate of a modification.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. Note that the drawings to be used are appropriately enlarged or reduced so that the part to be described can be recognized.

  In the following embodiments, for example, when “on the substrate” is described, the substrate is disposed so as to be in contact with the substrate, or is disposed on the substrate via another component, or the substrate. It is assumed that a part is arranged so as to be in contact with each other and a part is arranged via another component.

(First embodiment)
<Microlens array substrate>
The microlens array substrate of this embodiment will be described with reference to FIGS. FIG. 1 is a schematic plan view showing the arrangement of microlenses on the microlens array substrate of the first embodiment. 2A is a schematic cross-sectional view of the microlens array substrate along the line AA ′ in FIG. 1, FIG. 2B is an enlarged cross-sectional view showing a minute recess in the lens surface, and FIG. It is a figure which shows the relationship between a recessed part and the refractive index of an interface.

  The microlens array substrate of the present embodiment is used in a liquid crystal device as an electro-optical device to be described later to collect light incident on the liquid crystal device (incident light) and increase the use efficiency of incident light. .

As shown in FIG. 1, the microlens array substrate 25 </ b> A of the present embodiment includes a plurality of microlenses 24 </ b> A arranged in a matrix in the X direction and the Y direction orthogonal to each other in the substrate body 21. When viewed from the Z direction orthogonal to the X direction and the Y direction, the planar shape of the microlens 24A is circular, and the adjacent microlenses 24A are arranged so as to contact each other. The size of the microlens 24A is set corresponding to the size of a pixel of a liquid crystal device described later, and the lens diameter is approximately 5 μm to 20 μm. In other words, the arrangement pitch of the microlenses 24A in the X direction and the Y direction is uniform and is approximately 5 μm to 20 μm. The plurality of microlenses 24 </ b> A are included in the lens layer 22 </ b> A formed on the substrate body 21.
Note that the planar arrangement of the microlenses 24A is not limited to the matrix shape. Further, they are arranged corresponding to the arrangement of the pixels in the electro-optical device, and the arrangement pitch in the X direction and the Y direction may not be uniform.
Hereinafter, the microlens array substrate is referred to as an MLA (Micro Lens Array) substrate.

As shown in FIG. 2A, the MLA substrate 25A has a structure in which a substrate body 21 and a lens layer 22A are laminated. A plurality of concave and hemispherical lens surfaces 23 are formed on one surface 21 a of the substrate body 21. A lens layer 22 </ b> A is provided so as to fill each of the concave lens surfaces 23 and cover one surface 21 a of the substrate body 21.
The substrate body 21 is made of a transparent substrate such as quartz glass, and the lens layer 22A is made of a lens member having a refractive index larger than that of the substrate body 21. The surface of the lens layer 22A opposite to the lens surface 23 is subjected to a flattening process such as a CMP (Chemical Mechanical Polishing) process to alleviate the unevenness.

  FIG. 2B is an enlarged view showing the state of the lens surface 23 in an easy-to-understand manner by enlarging a portion “B” surrounded by a broken line in FIG. As shown in FIG. 2B, a large number of minute recesses 31 are formed on one surface 21a of the substrate body 21 on which the concave lens surface 23 is formed. The minute recess 31 is recessed in the surface 21a substantially along the Z direction (thickness direction of the substrate body 21). Further, in the lens surface 23, the depth d1 of the minute concave portion 31 at the center is smaller than the depth d2 of the minute concave portion 31 at the outer edge portion. That is, the depth of the minute recess 31 in the lens surface 23 increases as it goes from the center to the outer edge.

  Assuming that the refractive index of the lens layer 22A is n1 and the refractive index of the substrate body is n2, the refractive index of the interface (lens surface 23) provided with such minute recesses 31 is as shown in FIG. In response to the average depth D of the minute concave portion 31, it gradually changes from n1 to n2 or from n2 to n1. If the minute recess 31 is not present, the refractive index of the interface changes abruptly from n1 to n2 or from n2 to n1, and light enters the interface where such a change in refractive index occurs abruptly. Then, incident light is easily reflected at the interface. As in this embodiment, the light incident on the interface having a large number of minute recesses 31 is less likely to reflect incident light because the refractive index at the interface changes slowly. Such a micro three-dimensional structure including the micro recesses 31 is a kind of moth-eye structure. The minute recesses 31 are not necessarily formed at a uniform pitch. If the wavelength of incident light for which reflection at the interface is to be suppressed is, for example, in the visible light wavelength range, the average arrangement pitch of the minute recesses 31 is shorter than 400 nm on the short wavelength side in the visible light wavelength range, for example, 300 nm or less. I just need it. Moreover, if the average depth D of the micro recessed part 31 is about 50 nm-500 nm, reflection of the incident light (visible light) in the interface in which the micro recessed part 31 was provided can fully be suppressed. Hereinafter, a method for manufacturing the MLA substrate 25A having a large number of minute recesses 31 at the interface between the substrate body 21 and the lens layer 22A will be described.

<Manufacturing method of microlens array substrate>
A method for manufacturing the MLA substrate 25A of the present embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing a manufacturing method of the microlens array substrate of the first embodiment, FIGS. 4A to 4E are schematic cross-sectional views showing a manufacturing method of the microlens array substrate of the first embodiment, and FIG. a) is an electron micrograph showing a grain boundary of polycrystalline silicon, and (b) is a schematic diagram showing a minute recess.

  As shown in FIG. 3, the manufacturing method of the MLA substrate 25A of this embodiment includes a lens surface forming step (step S1), a mask layer forming step (step S2), an etching step (step S3), and a mask layer removal. The process (step S4) and the lens layer formation process (step S5) are included.

In the lens surface forming step (step S1) of FIG. 3, a first mask layer 60 having an opening 61 is formed on one surface 21a as the first surface of the substrate body 21, as shown in FIG. The opening 61 is formed at a position corresponding to the center of the lens surface 23 when viewed from the normal direction (Z direction) of the surface 21a. In step S1, the substrate body 21 is isotropically etched from the surface 21a side through the opening 61 to form the lens surface 23 as shown in FIG. For example, when the substrate body 21 is quartz glass, silicon oxynitride (SiO _x N _y ) can be used as the first mask layer 60. Silicon oxynitride (SiO _x N _y ) is formed on the surface 21a and patterned to form the first mask layer 60 having a plurality of openings 61. Examples of the isotropic etching include wet etching using an etching solution such as hydrofluoric acid and ammonium fluoride, and dry etching using a fluorine-based processing gas. The initial size (diameter) of the opening 61 is appropriately set according to the size (radius r) of the hemispherical lens surface 23 and the etching conditions of the substrate body 21.

  According to such an etching method, the substrate body 21 made of silicon oxide having an etching rate faster than that of silicon oxynitride is isotropically etched around the opening 61. As the substrate body 21 is etched, the etching of the first mask layer 60 made of silicon oxynitride also proceeds. Accordingly, the diameter of the opening 61 increases as the etching progresses. It is desirable to set the film thickness of the first mask layer 60 so that the etching of the first mask layer 60 is completed when the etching proceeds and the adjacent lens surfaces 23 come into contact with each other. According to this, the process of removing the first mask layer 60 is unnecessary. Note that the first mask layer 60 may be removed after the first mask layer 60 is formed using a material that is difficult to be etched by isotropic etching and the lens surface 23 is formed. Then, the process proceeds to step S2.

  In the mask layer forming step (step S2) in FIG. 3, as shown in FIG. 4C, a second mask layer 65 is formed to cover the unetched surface 21a and the lens surface 23 formed by etching. The second mask layer 65 is a mask layer in the present invention, and has a crystal structure. In the present embodiment, the second mask layer 65 is made of polycrystalline silicon having a thickness of about 50 nm to 100 nm. The second mask layer 65 made of polycrystalline silicon has a silicon crystal grain boundary as shown in FIG. The shape and size of the grain boundaries are not constant. The size of the crystal grain boundary depends on the polycrystalline silicon film forming method. In general, when the film thickness is large (thick), crystal growth proceeds and the crystal grain boundary tends to increase. In other words, by controlling the film formation method of the polycrystalline silicon, the size of the crystal grain boundary is controlled, and the minute recess 31 formed by etching through the second mask layer 65 in the next step S3. Can be controlled. Then, the process proceeds to step S3.

In the etching step (step S3) in FIG. 3, as shown in FIG. 4D, the substrate body 21 is anisotropically etched from the side on which the second mask layer 65 is formed. Specifically, for example, dry etching using a fluorine-based processing gas containing CHF ₃ and CF ₄ is performed. The fluorine-based processing gas enters the interface of the polycrystalline silicon grain boundaries in the second mask layer 65 and anisotropically etches the lens surface 23 covered with the second mask layer 65. Anisotropic etching is performed so as to proceed substantially in the normal direction (Z direction) of the surface 21a. As a result, as shown in FIG. 5B, anisotropic etching proceeds corresponding to the crystal grain boundary of polycrystalline silicon, and a minute recess 31 is formed in the etched portion. Further, a minute columnar body remains in a portion where the etching has not progressed. The anisotropic etching proceeds substantially in the Z direction, that is, from the one surface 21a of the substrate body 21 to the other surface 21b facing the substrate body 21. Therefore, due to the difference in the distance of the etching target surface to which the fluorine-based processing gas reaches by dry etching, as shown in FIG. 2B, the minute concave portion 31 is moved from the central portion of the lens surface 23 to the outer edge portion. The depth of becomes deeper. The anisotropic etching is stopped when the depth of the minute recess 31 is about 500 nm at the maximum. The second mask layer 65 is also etched by dry etching using a fluorine processing gas. Since the polycrystalline silicon is opaque, the remaining polycrystalline silicon is removed in the mask layer removing step (step S4) of FIG. 3 so as not to leave a polycrystalline silicon residue. As a method for removing polycrystalline silicon, wet etching using an aqueous solution of TMAH (tetramethylammonium hydroxide) can be mentioned. Then, the process proceeds to step S5.

In the lens layer forming step (step S5) in FIG. 3, as shown in FIG. 4E, a lens layer 22A that covers the lens surface 23 and the surface 21a of the substrate body 21 in which the minute recesses 31 are formed is formed. The lens layer 22A is formed in a thick film so as to fill the concave and hemispherical lens surface 23. The lens layer 22 </ b> A is composed of a lens member having a refractive index larger than that of the substrate body 21. For example, when quartz glass having a refractive index n of about 1.46 (when the wavelength of light is 550 nm) is used as the substrate body 21, silicon oxynitride (SiO _x N _y ) is used as the lens layer 22A. The refractive index n of silicon oxynitride (SiO _x N _y ) depends on the composition (ratio) of O and N, and the refractive index n of silicon oxide (SiO ₂ ) is 1.46 and the refraction of silicon nitride (Si ₃ N ₄ ). The rate n is between 2.0. As a method of forming a thick film of silicon oxynitride (SiO _x N _y ), a method using plasma CVD can be given. The film thickness of the lens layer 22A is approximately 5 μm to 10 μm. As a result, a microlens 24A having a refractive index n larger than that of the substrate body 21 is formed in a portion where each lens surface 23 is filled with the lens layer 22A. If the surface of the lens layer 22A opposite to the lens surface 23 is uneven, the variation in the angle of the incident light for each microlens 24A becomes large. Therefore, stable condensing for each microlens 24A. In order to obtain characteristics, it is desirable that the surface of the lens layer 22A be subjected to a planarization process. Examples of the planarization method include a CMP process and chemical etching. Or you may perform combining these processes.

<Electro-optical device>
Next, a liquid crystal device as an electro-optical device to which the microlens array (MLA) substrate 25A of this embodiment is applied will be described with reference to FIGS. FIG. 6 is a schematic plan view showing the configuration of the liquid crystal device of the first embodiment, and FIG. 7 is a schematic cross-sectional view showing the structure of the liquid crystal device of the first embodiment.
The liquid crystal device as the electro-optical device of the present embodiment is suitably used as a light modulation element (liquid crystal light valve) of a projection display device (liquid crystal projector) as an electronic apparatus described later.

  As shown in FIGS. 6 and 7, the liquid crystal device 100 as the electro-optical device according to the present embodiment includes an element substrate 10 and a counter substrate 20 that are arranged to face each other, and a liquid crystal layer 50 that is sandwiched between the pair of substrates. Have. The substrate body 11 of the element substrate 10 and the substrate body 21 of the counter substrate 20 are made of, for example, transparent quartz glass.

  The element substrate 10 is larger than the counter substrate 20, and both substrates are bonded together via a sealing material 40 disposed along the outer edge of the counter substrate 20, and a liquid crystal having positive or negative dielectric anisotropy is formed in the gap. A liquid crystal layer 50 as an electro-optical element is formed by being enclosed. As the sealing material 40, for example, an adhesive such as a thermosetting or ultraviolet curable epoxy resin is employed. A spacer (not shown) is mixed in the sealing material 40 to keep the distance between the pair of substrates constant.

  A pixel region E in which a plurality of pixels P are arranged is provided inside the sealing material 40. Further, a parting part 26 is provided between the sealing material 40 and the pixel region E so as to surround the pixel region E. The parting part 26 is made of, for example, a light shielding metal or metal oxide. The pixel region E may include dummy pixels arranged so as to surround the plurality of pixels P in addition to the plurality of pixels P contributing to display. Although not shown in FIG. 6, a light shielding portion (black matrix; BM) that divides a plurality of pixels P in a plane in the pixel region E is provided on the counter substrate 20. The light shielding part (BM) is provided in the same layer as the parting part 26, and hereinafter, the light shielding part (BM) will be described with reference numeral 26.

  A data line driving circuit 101 is provided between the first side portion along the terminal portion of the element substrate 10 and the sealing material 40. In addition, an inspection circuit 103 is provided between the sealing material 40 and the pixel region E along the second side facing the first side. Further, a scanning line driving circuit 102 is provided between the sealing material 40 and the pixel region E along the third and fourth sides that are orthogonal to the first side and face each other. A plurality of wirings 105 that connect the two scanning line driving circuits 102 are provided between the sealing material 40 on the second side and the inspection circuit 103.

  Wirings connected to the data line driving circuit 101 and the scanning line driving circuit 102 are connected to a plurality of external connection terminals 104 arranged along the first side. In the following description, it is assumed that the direction along the first side is the X direction and the direction along the third side is the Y direction. Note that the arrangement of the inspection circuit 103 is not limited to this, and the inspection circuit 103 may be provided at a position along the inner side of the sealant 40 between the data line driving circuit 101 and the pixel region E.

  As shown in FIG. 7, on the surface of the element substrate 10 on the liquid crystal layer 50 side, a transparent pixel electrode 15 provided for each pixel P, a thin film transistor (not shown) as a switching element, and a signal wiring 12 And an alignment film 18 that covers the pixel electrode 15 is formed. In addition, a light-shielding structure that prevents light from entering the semiconductor layer of the thin film transistor and causing unstable switching operation is employed. The element substrate 10 according to the present invention includes at least a substrate main body 11, a thin film transistor formed on the substrate main body 11, a signal wiring 12, a pixel electrode 15, and an alignment film 18. In the present embodiment, the signal wiring 12 is formed between adjacent pixel electrodes 15 and constitutes at least a part of the light shielding structure.

  The counter substrate 20 disposed to face the element substrate 10 covers the microlens array substrate 25A including the substrate body 21 and the lens layer 22A, the parting portion (light-shielding portion) 26 formed on the lens layer 22A side, and the same. The planarizing layer 27 thus formed, the common electrode 28 provided so as to cover the planarizing layer 27, and the alignment film 29 covering the common electrode 28 are included.

  The parting part 26 surrounds the pixel region E as shown in FIG. 6 and is provided at a position overlapping the scanning line driving circuit 102 and the inspection circuit 103 in plan view. Thus, the light incident on the peripheral circuit including these drive circuits from the counter substrate 20 side is shielded, and the peripheral circuit is prevented from malfunctioning due to the light. Further, unnecessary stray light is shielded from entering the pixel region E to ensure high contrast in the display of the pixel region E.

  The planarizing layer 27 is made of an inorganic material such as silicon oxide or silicon oxynitride, for example, and is provided so as to cover the parting portion 26 with light transmittance. As a method for forming such a flattening layer 27, for example, a method of forming a film using a plasma CVD method or the like can be given.

  The common electrode 28 is made of, for example, a transparent conductive film such as ITO (Indium Tin Oxide), covers the planarization layer 27, and includes an element substrate by vertical conduction portions 106 provided at the four corners of the counter substrate 20 as shown in FIG. It is electrically connected to the wiring on the 10 side.

  The alignment film 18 covering the pixel electrode 15 and the alignment film 29 covering the common electrode 28 are selected based on the optical design of the liquid crystal device 100. For example, by depositing an organic material such as polyimide and rubbing the surface, an organic alignment film obtained by subjecting liquid crystal molecules having positive dielectric anisotropy to a substantially horizontal alignment process, or vapor phase growth Examples thereof include an inorganic alignment film formed by depositing an inorganic material such as SiOx (silicon oxide) using a method and substantially vertically aligning liquid crystal molecules having negative dielectric anisotropy.

  Such a liquid crystal device 100 is a transmissive type, and is normally white mode in which the transmittance of the pixel P is maximized when no voltage is applied, or normally black in which the transmittance of the pixel P is minimized when no voltage is applied. Modal optical design is adopted. Polarizing elements are arranged and used according to the optical design on the light incident side and the light exit side, respectively. In this embodiment, a normally black mode is employed.

  In the liquid crystal device 100, the light L incident from the surface 21b side of the counter substrate 20 is collected for each pixel P by the microlens 24A. The light L does not necessarily enter the surface 21b from the normal direction, and the light L is microscopic in a certain angle range (for example, ± 20 degrees) with respect to the optical axis L0 of the microlens 24A provided for each pixel P. The light enters the lens 24A. The focus position of the microlens 24A is set so that the condensed light L is not blocked as much as possible by the light blocking portion 26 on the counter substrate 20 side or the light blocking structure on the element substrate 10 side. Therefore, display using the incident light L is performed more efficiently than in the case where the microlens array substrate 25A is not used for the counter substrate 20.

The effects of the first embodiment are as follows.
(1) Since the microlens array substrate 25A has a minute three-dimensional structure as a moth-eye structure composed of a large number of minute recesses 31 at least on the lens surface 23, the light incident on the microlens 24A is incident on the lens surface 23. It is possible to reduce the reflection. In other words, the microlens array substrate 25A that can efficiently collect incident light can be provided.
(2) According to the method of manufacturing the microlens array substrate 25A, the concave and hemispherical lens surface 23 of the substrate body 21 is anisotropically etched from the Z direction (the thickness direction of the substrate body 21). A minute recess 31 that is recessed in the Z direction is formed. Since anisotropic etching is performed through the second mask layer 65 made of polycrystalline silicon, a large number of minute recesses 31 are formed not only on the flat surface 21a but also on the hemispherical lens surface 23. Can do.
(3) The liquid crystal device 100 using the micro lens array substrate 25A as the counter substrate 20 can perform bright display by efficiently using the light L incident from the counter substrate 20 side for each pixel P. In addition, the depth of the minute recess 31 gradually increases from the center of the lens surface 23 toward the outer edge. As shown in FIG. 7, the light L incident along the optical axis L0 of the micro lens 24A has a smaller incident angle with respect to the lens surface 23 as it goes to the outer edge of the lens surface 23, and is reflected as the incident angle is smaller. It becomes easy. According to the microlens array substrate 25A of the present embodiment, the depth d2 of the minute recess 31 at the outer edge portion of the lens surface 23 is deeper (larger) than the depth d1 of the central portion. Therefore, the change in the refractive index at the interface (lens surface 23) is more gentle at the outer edge than at the center, and the reflection of the light L at the outer edge of the lens surface 23 is reduced. That is, the liquid crystal device 100 capable of displaying brighter can be provided.

(Second Embodiment)
<Other microlens array substrates>
Next, the microlens array substrate of the second embodiment will be described with reference to FIGS. FIG. 8 is a schematic plan view showing the arrangement of microlenses on the microlens array substrate of the second embodiment. FIG. 9A is a schematic cross-sectional view of the microlens array substrate taken along the line CC ′ of FIG. 8, and FIG. 9B is an enlarged cross-sectional view showing minute concave portions on the lens surface. The microlens array substrate of the second embodiment includes a microlens having a convex lens surface on the substrate body 21 side which is a transparent substrate. The same components as those of the microlens array substrate 25A in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
Further, the microlens array substrate of the second embodiment can be used as the counter substrate 20 of the liquid crystal device 150 described later (see FIG. 13).

As shown in FIG. 8, the microlens array substrate 25 </ b> B of the present embodiment has a plurality of microlenses 24 </ b> B arranged in a matrix in the X and Y directions orthogonal to each other in the substrate body 21. When viewed from the Z direction perpendicular to the X direction and the Y direction, the planar shape of the microlens 24B is circular, and the adjacent microlenses 24B are arranged so as to contact each other. The size of the microlens 24B is set corresponding to the size of a pixel of the liquid crystal device 150 to be described later, and the lens diameter is approximately 5 μm to 20 μm. In other words, the arrangement pitch of the microlenses 24B in the X direction and the Y direction is uniform. As will be described in detail later, the plurality of microlenses 24 </ b> B are formed on a lens layer 22 </ b> B laminated on the substrate body 21.
Note that the planar arrangement of the microlenses 24B is not limited to the matrix shape. Further, they are arranged corresponding to the arrangement of the pixels in the electro-optical device, and the arrangement pitch in the X direction and the Y direction may not be uniform.
Also in this embodiment, the microlens array substrate is hereinafter referred to as an MLA (Micro Lens Array) substrate.

As shown in FIG. 9A, the MLA substrate 25B has a structure in which a substrate body 21, a lens layer 22B, and a transparent layer 22T are laminated. A plurality of convex and hemispherical lens surfaces 23 are formed on one surface 22s of the lens layer 22B. That is, a plurality of convex and hemispherical microlenses 24B are formed on the lens layer 22B.
The substrate body 21 is made of a transparent substrate such as quartz glass, and the lens layer 22B is made of a lens member having a refractive index larger than that of the substrate body 21. The transparent layer 22T is made of a member having a refractive index smaller than that of the lens layer 22B. The surface of the transparent layer 22T opposite to the lens surface 23 is flat.

  FIG. 9B is an enlarged view showing the state of the lens surface 23 in an easy-to-understand manner by enlarging the portion “F” surrounded by the broken line in FIG. As shown in FIG. 9B, a large number of minute recesses 31 are formed on one surface 22s of the lens layer 22B on which the convex microlenses 24B are formed. The minute recess 31 is recessed along the Z direction (the thickness direction of the lens layer 22B) on the surface 22s. Further, in the lens surface 23, the depth of the central minute recess 31 is shallower than the depth of the outer edge minute recess 31. That is, the depth of the minute recess 31 in the lens surface 23 increases as it goes from the center to the outer edge. In addition, in FIG.9 (b), the depth relationship of such a micro recessed part 31 is not reflected correctly.

  When the refractive index of the transparent layer 22T is n3 and the refractive index of the lens layer 22B is n2, the refractive index of the interface (lens surface 23) provided with such a minute recess 31 is the same as in the first embodiment. Corresponding to the average depth D of the minute recess 31, it gradually changes from n3 to n2 or from n2 to n3. If there is no minute recess 31, the refractive index of the interface changes abruptly from n3 to n2 or from n2 to n3, and light enters the interface where such a change in refractive index occurs abruptly. Then, incident light is easily reflected at the interface. As in this embodiment, the light incident on the interface having a large number of minute recesses 31 is less likely to reflect incident light because the refractive index at the interface changes slowly. The basic configuration of the minute recesses 31 is the same as that of the first embodiment. If the wavelength of incident light for which reflection at the interface is to be suppressed is, for example, in the visible light wavelength range, the average arrangement pitch of the minute recesses 31 is In the visible light wavelength range, it may be shorter than 400 nm on the short wavelength side, for example, 300 nm or less, and may not be arranged at regular intervals. If the average depth D of the minute recesses 31 is about 50 nm to 500 nm, reflection of incident light at the interface where the minute recesses 31 are provided can be sufficiently suppressed. Hereinafter, a method for manufacturing the MLA substrate 25B having a large number of minute concave portions 31 at the interface between the lens layer 22B and the transparent layer 22T will be described.

<Manufacturing method of other microlens array substrate>
A method for manufacturing the MLA substrate 25B of the present embodiment will be described with reference to FIGS. FIG. 10 is a flowchart showing a method for manufacturing a microlens array substrate according to the second embodiment. FIGS. 11A to 11D and FIGS. 12E to 12H are steps for manufacturing the microlens array substrate according to the second embodiment. It is a schematic sectional drawing which shows a method.

  As shown in FIG. 10, the manufacturing method of the microlens array (MLA) substrate 25B of this embodiment includes a lens surface forming step (step S11), a mask layer forming step (step S12), and an etching step (step S13). And a mask layer removing step (step S14) and a transparent layer forming step (step S15).

In the lens surface forming step (step S11) of FIG. 10, first, as shown in FIG. 11A, a lens layer 22B that covers one surface 21a of the substrate body 21 is formed. For example, the substrate body 21 is made of quartz glass having a refractive index n of 1.46, and the lens layer 22B is made of SiON (silicon oxynitride; refractive index n = 1.64) having a refractive index n larger than that of the substrate body 21. Is formed. Examples of the method for forming the lens layer 22B made of SiON include a sputtering method and a plasma CVD method. The thickness of the lens layer 22B is, for example, 5 μm to 20 μm.
Next, as shown in FIG. 11B, a first mask layer 60 covering the lens layer 22B is formed. The first mask layer 60 is formed to have an opening 62 corresponding to a region where a plurality of microlenses are formed. Subsequently, a heat-deformable photosensitive resin layer covering at least a region where a plurality of microlenses are formed is formed, and this is exposed and developed to form a resin pattern 80 corresponding to each microlens.
Next, the resin pattern 80 is heated to a deformation temperature or higher. By heating above the deformation temperature, the resin pattern 80 is thermally deformed and a hemispherical resin pattern 81 is formed by surface tension as shown in FIG. Then, the lens layer 22B having the first mask layer 60 and the resin pattern 81 formed on the surface 22s is anisotropically etched from the surface 22s side, thereby transferring the hemispherical resin pattern 81 to the lens layer 22B. As shown in (d), a plurality of microlenses 24B having convex and hemispherical lens surfaces 23 are formed. As the anisotropic etching, dry etching using a fluorine-based processing gas containing CHF ₃ and CF ₄ can be cited as in the first embodiment. The anisotropic etching is terminated when the outer edges of the adjacent microlenses 24B are in contact with each other. Then, the process proceeds to step S12.

  In the mask layer forming step (step S12) in FIG. 10, as shown in FIG. 12E, a second mask layer 65 as a mask layer in the present invention that covers the surface 22s and the plurality of microlenses 24B is formed. As described above, the second mask layer 65 is made of polycrystalline silicon having a thickness of 50 nm to 100 nm. Then, the process proceeds to step S13.

In the etching step (step S13) of FIG. 10, as shown in FIG. 12 (f), anisotropic etching is performed through the second mask layer 65, and the minute recesses 31 are formed on the surface 22s and the lens surface 23 of the microlens 24B. Form. As the anisotropic etching, dry etching using a fluorine-based processing gas containing CHF ₃ and CF ₄ can be cited as in the first embodiment. The anisotropic etching proceeds from the surface 22s side toward the surface 21b facing the surface 22s in the Z direction. Therefore, a large number of minute recesses 31 that are recessed in the substantially Z direction are formed on the surface 22 s and the lens surface 23. Further, as shown in FIG. 9B, anisotropic etching is performed so that the depth of the minute recess 31 at the outer edge portion is deeper than the depth of the minute recess 31 at the center of the lens surface 23. As such an anisotropic etching method, for example, dry etching conditions are set so that the etching rate is maximized when the distance between the surface to be etched and the electrode in dry etching is a predetermined distance. Then, the substrate body 21 is disposed so that the outer edge portion of the lens surface 23 is at the predetermined distance from the electrode, and dry etching is performed. As a result, the etching rate decreases at the central portion of the lens surface 23 where the distance to the electrode is shorter than the predetermined distance, so that the depth of the minute concave portion 31 formed at the central portion is shallower than the outer edge portion. Then, the process proceeds to step S14.

  In the mask layer removing step (step S14) in FIG. 10, as shown in FIG. 12G, the second mask layer 65 covering the surface 22s and the lens surface 23 of the lens layer 22B is removed. As a method for removing the second mask layer 65 made of polycrystalline silicon, as in the first embodiment, wet etching using an aqueous solution of TMAH (tetramethylammonium hydroxide) may be mentioned. Then, the process proceeds to step S15.

In the transparent layer forming step (step S15) in FIG. 10, as shown in FIG. 12 (h), a transparent layer 22T that covers the surface 22s and the lens surface 23 of the lens layer 22B in which the minute recesses 31 are formed is formed. The transparent layer 22T is formed as a thick film so as to fill the convex and hemispherical microlenses 24B. The transparent layer 22T is composed of a member having a smaller refractive index than the lens layer 22B. For example, when SiON (silicon oxynitride) having a refractive index n of about 1.64 (when the wavelength of light is 550 nm) is used as the lens layer 22B, the refractive index n is smaller than SiON as the transparent layer 22T. SiO ₂ (silicon oxide; refractive index n is approximately 1.46) or the like is used. The film thickness of the transparent layer 22T is approximately 5 μm to 10 μm. Thereby, the light incident from the substrate body 21 side can be condensed on the transparent layer 22T side by the microlens 24B. In addition, the transparent layer 22T can protect each micro lens 24B, that is, the lens surface 23 on which the minute concave portion 31 is formed, from an external impact or the like. In addition, it is not preferable that irregularities are generated on the surface of the transparent layer 22T opposite to the lens surface 23 because the irregularities are reflected on the surface of an electrode formed on the surface later. In addition, since the light collected by the microlens 24B may be diffusely reflected, the surface of the transparent layer 22T (the surface on the opposite side to the lens surface 23) can be obtained in order to obtain a stable light collection characteristic for each microlens 24B. ) Is preferably flat.

<Electro-optical device>
Next, a liquid crystal device as an electro-optical device to which the microlens array substrate 25B of the second embodiment is applied will be described with reference to FIG. FIG. 13 is a schematic cross-sectional view showing a liquid crystal device as an electro-optical device according to the second embodiment. The liquid crystal device as the electro-optical device of the second embodiment is obtained by applying the microlens array substrate 25B on the counter substrate 20 side to the liquid crystal device 100 of the first embodiment. Therefore, the same components as those of the liquid crystal device 100 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The liquid crystal device according to the second embodiment is also suitably used as a light modulation element (liquid crystal light valve) of a projection display device (liquid crystal projector) as an electronic device to be described later.

  As shown in FIG. 13, the liquid crystal device 150 as the electro-optical device of the present embodiment includes the element substrate 10 and the counter substrate 20 that are arranged to face each other, and a liquid crystal layer 50 that is sandwiched between the pair of substrates. The substrate body 11 of the element substrate 10 and the substrate body 21 of the counter substrate 20 are made of, for example, transparent quartz glass.

  Both substrates are bonded together via a sealing material (not shown) disposed along the outer edge of the counter substrate 20, and a liquid crystal having positive or negative dielectric anisotropy is sealed in the gap to serve as an electro-optical element. A liquid crystal layer 50 is configured.

  The element substrate 10 includes at least a substrate body 11, a thin film transistor formed on the substrate body 11, a signal wiring 12, a pixel electrode 15, and an alignment film 18. In the present embodiment, the signal wiring 12 is formed between adjacent pixel electrodes 15 and constitutes at least a part of a light shielding structure that shields light incident on the thin film transistor.

  The counter substrate 20 disposed to face the element substrate 10 includes a microlens array substrate 25B including a substrate body 21, a lens layer 22B, and a transparent layer 22T, a parting portion (light-shielding portion) 26 formed on the transparent layer 22T side, The flattening layer 27 is formed so as to cover it, the common electrode 28 is provided so as to cover the flattening layer 27, and the alignment film 29 covers the common electrode 28.

  Such a liquid crystal device 150 is a transmission type, and the transmittance of the pixel is larger than when the voltage is not applied and becomes a bright display when compared with the voltage application, or the transmittance of the pixel is the voltage when the voltage is not applied. A normally black mode optical design that is smaller than that at the time of application and provides a dark display is employed. Polarizing elements are arranged and used according to the optical design on the light incident side and the light exit side, respectively. In this embodiment, a normally black mode is employed.

  In the liquid crystal device 150, the light L incident from the surface 21b side of the counter substrate 20 is condensed for each pixel by the microlens 24B. The light L does not necessarily enter the surface 21b from the normal direction, and the microlens has a certain angle range (for example, ± 20 degrees) with respect to the optical axis L0 of the microlens 24B provided for each pixel. It is incident on 24B. The focus position of the microlens 24B is set so that the condensed light L is not blocked as much as possible by the light blocking portion 26 on the counter substrate 20 side or the light blocking structure on the element substrate 10 side. Therefore, the display using the incident light L is performed more efficiently than when the counter lens 20 does not use the microlens array substrate 25B.

The effects of the second embodiment are as follows.
(1) Since the microlens array substrate 25B has a minute three-dimensional structure as a moth-eye structure composed of a large number of minute recesses 31 formed on the convex lens surface 23, the light incident on the microlens 24B is a lens. Reflection on the surface 23 can be reduced. In other words, the microlens array substrate 25B that can efficiently collect incident light can be provided.
(2) According to the manufacturing method of the microlens array substrate 25B, the convex and hemispherical lens surface 23 of the substrate body 21 is anisotropically etched from the Z direction (thickness direction of the substrate body 21). A minute recess 31 is formed. Since anisotropic etching is performed through the second mask layer 65 made of polycrystalline silicon, not only the flat surface 22s of the lens layer 22B but also the convex and hemispherical lens surface 23 are uniformly distributed. Can be formed.
(3) The liquid crystal device 150 using the microlens array substrate 25B as the counter substrate 20 uses the liquid crystal device 150 capable of performing bright display by efficiently using the light L incident from the counter substrate 20 side for each pixel. Can be provided.

  In the first and second embodiments, the minute recess 31 is formed by anisotropically etching at least the lens surface 23 via the second mask layer 65 made of polycrystalline silicon. It can be said that the unevenness is generated on the lens surface 23 by anisotropic etching, and the micro three-dimensional structure as the moth-eye structure is composed of micro convex portions (micro columnar bodies).

(Third embodiment)
<Electronic equipment>
Next, a projection display device (liquid crystal projector) as an electronic apparatus according to this embodiment will be described with reference to FIG. FIG. 14 is a schematic diagram showing the configuration of the projection display device.

As shown in FIG. 14, a projection display device (liquid crystal projector) 1000 as an electronic apparatus according to this embodiment includes a polarization illumination device 1100 arranged along the system optical axis L1 and two dichroic devices as light separation means. Mirrors 1104, 1105, three reflection mirrors 1106, 1107, 1108, five relay lenses 1201, 1202, 1203, 1204, 1205, and three transmissive liquid crystal light valves 1210, 1220, 1230 as light modulation means And a cross dichroic prism 1206 as light combining means and a projection lens 1207 as projection means.
Polarized illumination apparatus 1100 excluding the projection lens 1207, two dichroic mirrors 1104 and 1105, three reflection mirrors 1106, 1107 and 1108, five relay lenses 1201, 1202, 1203, 1204 and 1205, and three liquid crystals A configuration including the light valves 1210, 1220, and 1230 and the cross dichroic prism 1206 corresponds to the optical unit.

  The polarized light illumination device 1100 is generally configured by a lamp unit 1101 as a light source composed of a white light source such as an ultra-high pressure mercury lamp or a halogen lamp, an integrator lens 1102, and a polarization conversion element 1103.

  The dichroic mirror 1104 reflects red light (R) and transmits green light (G) and blue light (B) among the polarized light beams emitted from the polarization illumination device 1100. Another dichroic mirror 1105 reflects the green light (G) transmitted through the dichroic mirror 1104 and transmits the blue light (B).

The red light (R) reflected by the dichroic mirror 1104 is reflected by the reflection mirror 1106 and then enters the liquid crystal light valve 1210 via the relay lens 1205.
Green light (G) reflected by the dichroic mirror 1105 enters the liquid crystal light valve 1220 via the relay lens 1204.
The blue light (B) transmitted through the dichroic mirror 1105 enters the liquid crystal light valve 1230 via a light guide system including three relay lenses 1201, 1202, 1203 and two reflection mirrors 1107, 1108.

  The liquid crystal light valves 1210, 1220, and 1230 are disposed to face the incident surfaces of the cross dichroic prism 1206 for each color light. The color light incident on the liquid crystal light valves 1210, 1220, and 1230 is modulated based on video information (video signal) and emitted toward the cross dichroic prism 1206. In this prism, four right-angle prisms are bonded together, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface thereof. The three color lights are synthesized by these dielectric multilayer films, and the light representing the color image is synthesized. The synthesized light is projected on the screen 1300 by the projection lens 1207 which is a projection optical system, and the image is enlarged and displayed.

  The liquid crystal light valve 1210 is obtained by applying the liquid crystal device 100 or the liquid crystal device 150 described above. The liquid crystal device 100 (liquid crystal device 150) is arranged with a gap between a pair of polarizing elements arranged in crossed Nicols on the incident side and the emission side of colored light. The liquid crystal device 100 (liquid crystal device 150) is arranged with respect to the cross dichroic prism 1206 so that the colored light enters from the counter substrate 20 side, passes through the liquid crystal device 100 (liquid crystal device 150), and is emitted from the element substrate 10 side. ing. The same applies to the other liquid crystal light valves 1220 and 1230.

  According to such a projection display apparatus 1000, the liquid crystal device 100 (liquid crystal device 150) that can effectively use each color light (incident light) of R, G, and B is used for the liquid crystal light valves 1210, 1220, and 1230. Therefore, bright display can be realized.

  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 substrate with such a change In addition, the manufacturing method of the microlens array substrate and the electro-optical device and electronic apparatus to which the microlens array substrate is applied are also included in the technical scope of the present invention. Various modifications other than the above embodiment are conceivable. Hereinafter, a modification will be described.

(Modification 1) In the method of manufacturing the microlens array substrates 25A and 25B of the first and second embodiments, the method of forming the minute recesses 31 in the lens surface 23 is not limited to anisotropic etching. 15A and 15B are schematic cross-sectional views showing the configuration of a microlens array substrate according to a modification. The same components as those of the microlens array substrate 25A of the first embodiment are denoted by the same reference numerals for description. For example, as shown in FIGS. 15A and 15B, the microlens array substrate 25 </ b> C according to the modification is formed by laminating a substrate body 21 and a lens layer 22 </ b> C having a refractive index larger than that of the substrate body 21. is there. A plurality of concave and hemispherical lens surfaces 23 are formed on one surface 21 a of the substrate body 21. The lens layer 22C is formed to fill the concave lens surface 23 and cover the surface 21a. The lens layer 22 </ b> C has a plurality of microlenses 24 </ b> C corresponding to the plurality of lens surfaces 23.
On the surface 21a and the lens surface 23, a minute recess 32 is formed. The minute recesses 32 are recessed in the substantially normal direction of the surface 21a on the surface 21a. Further, the lens surface 23 is recessed in a substantially normal direction of a tangent to the lens surface 23. The average depth d3 of the minute recesses 32 is substantially equal on the surface 21a and the lens surface 23.
In such a method of manufacturing the microlens array substrate 25C, a step of forming a plurality of concave lens surfaces 23 on the surface 21a of the substrate body 21 as a transparent substrate (step S1), and the surface 21a and the concave lens surface 23 are formed. A step of forming a second mask layer 65 made of polycrystalline silicon (step S2), an etching step of isotropically etching the surface 21a and the lens surface 23 via the second mask layer 65, and a second mask layer 65 And a step of filling the concave lens surface 23 to form the lens layer 22C.
In the etching step, the surface 21a and the lens surface 23 are isotropically etched, so that the surface 21a and the lens surface 23 can form the minute recesses 32 that are recessed at substantially the same depth in the normal direction. . Examples of the isotropic etching include wet etching using an aqueous solution of hydrofluoric acid or ammonium fluoride.
According to the modified microlens array substrate 25C and the manufacturing method thereof, since a large number of minute recesses 32 (small three-dimensional structures) are evenly formed at least on the lens surface 23, incidence on the lens surface 23 occurs. Light reflection can be reduced evenly. In addition, when the micro recessed part 32 is formed using isotropic etching, the part in which etching did not advance becomes a spindle-shaped micro convex part.

  (Modification 2) In the first and second embodiments, the lens surfaces 23 of the microlenses 24A and 24B are not limited to be hemispherical. For example, the lens surface 23 may be an aspheric surface. As a method of forming the aspheric lens surface 23 on the substrate body 21, a known method can be adopted.

  (Modification 3) In the microlens array substrate 25B, the transparent layer 22T covering the convex microlens 24B is not an essential configuration. Even in the absence of the transparent layer 22T, if the layer in contact with the microlens 24B is smaller than the refractive index of the lens layer 22B, for example, an air layer, the light incident from the other surface 21b of the substrate body 21 is collected by the microlens 24B. can do.

  (Modification 4) The electro-optical device to which the micro lens array substrates 25A and 25B can be applied is not limited to the liquid crystal devices 100 and 150. For example, the above-described microlens array substrates 25A and 25B can be used as condensing means such as an imaging device or a lighting device provided with a light receiving element such as a CCD.

  (Modification 5) An electronic apparatus to which the liquid crystal devices 100 and 150 using the microlens array substrates 25A and 25B can be applied is not limited to the projection display device (liquid crystal projector) 1000. For example, projection-type HUD (head-up display), direct-view type HMD (head-mounted display), electronic book, personal computer, digital still camera, liquid crystal television, viewfinder-type or monitor direct-view type video recorder, car navigation system It can be suitably used as a display unit of an information terminal device such as an electronic notebook or POS.

  21 ... Substrate body as a transparent substrate, 21a ... One surface as a first surface, 22A, 22B, 22C ... Lens layer, 22T ... Transparent layer, 23 ... Lens surface, 24A, 24B, 24C ... Microlens, 25A, 25B, 25C... Micro lens array substrate 31, 32... Recessed concave portion 65. Second mask layer as mask layer, 100 and 150. Liquid crystal device as electro-optical device, 1000... Projection type display device as electronic device.

Claims (13)

A transparent substrate having a plurality of concave lens surfaces on the first surface;
A lens layer formed by filling the lens surface and having a refractive index different from that of the transparent substrate,
A microlens array substrate, wherein a micro three-dimensional structure is formed on at least the lens surface in contact with the lens layer. A transparent substrate having a plurality of convex lens surfaces on the first surface;
A microlens array substrate, wherein a micro three-dimensional structure is formed on the lens surface. A lens layer covering the first surface of the transparent substrate;
The lens surface is formed on the lens layer;
The microlens array substrate according to claim 2, further comprising a transparent layer formed to cover the lens surface and having a refractive index smaller than that of the lens layer.   The microlens array substrate according to any one of claims 1 to 3, wherein the minute three-dimensional structure includes minute concave portions.   The microlens array substrate according to claim 4, wherein the minute recesses are recessed in a substantially normal direction of the first surface of the transparent substrate.   6. The microlens array substrate according to claim 5, wherein the depth of the minute concave portion becomes deeper from a center portion of the lens surface toward an outer edge portion of the lens surface. Forming a plurality of concave lens surfaces on the first surface of the transparent substrate;
Forming a mask layer having a crystal structure covering at least the lens surface;
Etching through the mask layer to form a minute three-dimensional structure consisting of minute recesses on the lens surface;
Removing the mask layer;
And a step of filling a lens member on the lens surface from which the mask layer has been removed to form a lens layer. Forming a plurality of convex lens surfaces on the first surface of the transparent substrate;
Forming a mask layer having a crystal structure covering at least the lens surface;
Etching through the mask layer to form a minute three-dimensional structure consisting of minute recesses on the lens surface;
And a step of removing the mask layer. A method of manufacturing a microlens array substrate, comprising: The lens surface is formed on a lens layer covering the first surface of the transparent substrate,
9. The method of manufacturing a microlens array substrate according to claim 8, further comprising a step of forming a transparent layer that covers the lens surface using a member having a refractive index smaller than that of the lens layer. The mask layer is made of polycrystalline silicon;
10. The microlens array substrate according to claim 7, wherein in the etching step, anisotropic etching is performed on the mask layer from a normal direction of the first surface. Method.   11. The micro etching according to claim 10, wherein in the etching step, the anisotropic etching is performed so that the depth of the minute concave portion becomes deeper from a center portion of the lens surface toward an outer edge portion of the lens surface. A method of manufacturing a lens array substrate.   An electro-optical device comprising the microlens array substrate according to any one of claims 1 to 6.   An electronic apparatus comprising the electro-optical device according to claim 12.