Patent Publication Number: US-2016245961-A1

Title: Lens array substrate, electrooptical device, electronic apparatus, and method of manufacturing lens array substrate

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a lens array substrate, an electrooptical device, an electronic apparatus, and a method of manufacturing a lens array substrate. 
     2. Related Art 
     An electrooptical device with an electrooptical substance, such as liquid crystal, between an element substrate and a facing substrate is known. As such an electrooptical device, a liquid crystal device used as a liquid crystal light valve for a projector can be exemplified. In the liquid crystal device, a light shielding portion is provided in a region in which switching elements, wirings, and the like are arranged, and a part of incident light is blocked by the light shielding portion and is not utilized. Thus, a configuration for enhancing the efficiency of utilizing light in the liquid crystal device by providing lenses (microlenses) on a side of one substrate, causing the lenses to collect the light, which is blocked by the light shielding portion arranged at a boundary between pixels, as a part of the light that is incident on the liquid crystal device, and causing the collected light to be incident on the inside of openings of pixels is known (see JP-A-11-202314 and JP-A-2009-271468, for example). 
     According to the liquid crystal device disclosed in JP-A-11-202314, a light blocking film is formed of a metal material such as chromium, nickel, or aluminum in a parting region (peripheral parting region) in a periphery of a display region. In addition, convex microlenses that are curved toward the outside from the substrate are arranged in the display region, and convex dummy microlenses that are curved toward the outside from the substrate are arranged in the parting region so as to overlap the light blocking film in plan view. The microlenses that are curved toward the outside from the substrate are formed by transferring lens shapes, which are formed by exposing a photosensitive material to light, patterning the photosensitive material, and performing heat treatment thereon, to a substrate by anisotropic etching. Since the amount of removal is larger in the outermost periphery than the inside thereof in the anisotropic etching and differences in the shapes of the microlenses occur, variations in the properties of the microlenses occur. Thus, dummy microlenses that do not contribute to display are arranged in the periphery of the microlenses so as to prevent the occurrence of differences in the shapes of the microlenses in the display region. The plurality of dummy microlenses are formed on one side in one horizontal scanning direction, and the number thereof is not particularly limited. 
     According to the liquid display device disclosed in JP-A-2009-271468, concave portions are formed in a display region on a substrate, and a groove is formed in a parting region. In addition, convex microlenses that are curved toward the side of the substrate are formed by filling the concave portions in the substrate with a lens layer (filling layer) made of resin or an inorganic material, and an optical path length adjustment layer (cover layer) for adjusting a focal distance of the microlenses is formed of resin or an inorganic material so as to cover the lens layer. Since the lens layer is formed so as to be lifted in the parting region in a case in which the groove is not formed in the parting region, a large level difference is generated on the surface of the lens layer between the display region and the parting region, which brings about an increase in the number of processes such as polishing for flattening the surface of the lens layer. For this reason, the level difference in the surface of the lens layer between the display region and the parting region is suppressed by forming the groove in the parting region, and it is attempted to reduce the number of processes in the flattening processing such as polishing. 
     Incidentally, in the liquid crystal device described in JP-A-11-202314, light reflected by the light blocking film that is formed of the metal material is added in the parting region when the photosensitive material is exposed to light. Therefore, the intensity of light with which the photosensitive material is irradiated further increases as compared with that in the display region. For this reason, the diameter of each dummy microlens that is formed in the parting region becomes smaller than the diameter of each microlens in the display region. In doing so, the shapes of the microlenses in the display region and the shapes of the dummy microlenses with a smaller diameter in the parting region are reflected on the surface of the optical path length adjustment layer in the case in which the optical path length adjustment layer is formed so as to cover the convex microlenses. Therefore, since the density of the material of the optical path length adjustment layer per unit volume during the polishing differs between the display region and the parting region due to the difference in the diameters of the microlenses and the dummy microlenses in the process of flattening the surface of the optical path length adjustment layer, the number of processes in the flattening processing increases. However, JP-A-11-202314 does not include any consideration about the flattening processing in the case in which the optical path length adjustment layer is formed so as to cover the microlens since a structure of attaching a cover glass to the side, on which the microlenses are formed, of the substrate with an adhesive is employed. 
     It is possible to suppress a large level difference between the region in which the dummy microlenses are arranged and the peripheral region thereof, which is generated on the surface of the optical path length adjustment layer by further forming the groove as disclosed in JP-A-2009-271468 in the periphery of the dummy microlenses in the parting region. However, the density of the material of the optical path length adjustment layer per unit volume in the process of flattening the surface of the optical path length adjustment layer differs in three different levels in the display region in which the microlenses are arranged, the peripheral region in which the dummy microlenses are arranged, and the further peripheral region in which the groove is formed in this case. Therefore, there is concern that the number of processes such as polishing for flattening the surface of the optical path length adjustment layer increases depending on the setting of the depth, the width, and the like of the groove, and that productivity deteriorates. 
     SUMMARY 
     The invention can be realized in the following aspects or application examples. 
     APPLICATION EXAMPLE 1 
     According to this application example, there is provided a lens array substrate including: a substrate that includes a plurality of concave portions in a first region on a first surface; a first lens layer that is formed of a material with an optical refraction index difference from that of the substrate so as to cover the first surface and fill the plurality of concave portions; a first light transmitting layer that is formed so as to cover the first lens layer; a light shielding portion that is formed in a second region surrounding the first region on the first light transmitting layer; a second lens layer that is formed so as to cover the first light transmitting layer and the light shielding portion and includes a plurality of first convex portions arranged in the first region so as to overlap the respective concave portions in a plane and a plurality of second convex portions arranged in the second region so as to overlap the light shielding portion in a plane; and a second light transmitting layer that is formed of a material with an optical refraction index difference from that of the second lens layer so as to cover the second lens layer and includes a substantially flat surface, in which the plurality of second convex portions are arranged in a line so as to surround the plurality of first convex portions. 
     According to the configuration of this application example, the lens array substrate includes, in the first region, a two-stage lens array of lenses that are formed by filling the concave portions of the substrate with the first lens layer and are curved toward the side of the substrate and lenses that are formed by covering the first convex portions of the second lens layer with the second light transmitting layer and are curved toward the opposite side to the substrate. In addition, the lens array substrate includes, in the second region, dummy lenses that are formed by covering the second convex portions arranged in the periphery of the first convex portions of the second lens layer with the second light transmitting layer and overlap the light shielding portion in a plane. Therefore, since the second convex portions are formed in the periphery of the first convex portions when the first convex portions are formed by transferring lens shapes formed by exposing a photosensitive material to light, patterning the photosensitive material, and performing heat treatment thereon to the second lens layer by anisotropic etching, it is possible to further reduce the differences in shape of the first convex portions arranged in the first region and to further uniformize the properties of the lenses as compared with a case in which the second convex portions are not formed. 
     According to such a lens array substrate, the diameter of the second convex portions that overlap the light shielding portion in a plane is smaller than the diameter of the first convex portions due to light reflected by the light shielding portion when the lens shape is formed by exposing the photosensitive material layer to light. Therefore, a difference in the density of the material of the second light transmitting layer per unit volume occurs at a portion at which the first convex portions and the second convex portions are adjacent to each other when the surface of the second light transmitting layer that reflects the shapes of the first convex portions and the shapes of the second convex portions is flattened. Here, since the second convex portions that are arranged in the periphery of the first convex portions are in a line in this application example, it is possible to reduce the difference in the density of the material of the second light transmitting layer per unit volume between the first region in which the first convex portions are arranged and the second region in which the second convex portions are arranged as compared with a case in which the second convex portions are arranged in a plurality of lines. In doing so, it is possible to enhance flatness of the surface of the second light transmitting layer that functions as a superficial layer of the lens array substrate. In addition, it is possible to reduce the number of processes in the flattening processing of the second light transmitting layer in manufacturing the lens array substrate and to thereby enhance productivity of the lens array substrate. 
     APPLICATION EXAMPLE 2 
     In the lens array substrate according to the application example, it is preferable that the second lens layer includes a third convex portion that is provided in the second region so as to overlap the light shielding portion in a plane and is arranged so as to surround the plurality of second convex portions. 
     According to the configuration of this application example, the third convex portion is arranged in the periphery of second convex portions on the second lens layer. Therefore, it is possible to reduce the difference in the density of the material of the second light transmitting layer per unit volume between the region in which the second convex portions are arranged and a peripheral region in which the third convex portion is arranged. In doing so, it is possible to further enhance the flatness of the surface of the lens array substrate. In addition, it is possible to further reduce the number of processes in the flattening processing of the second light transmitting layer in manufacturing the lens array substrate. 
     APPLICATION EXAMPLE 3 
     In the lens array substrate according to the application example, it is preferable that the third convex portion is provided in a frame shape. 
     According to the configuration of this application example, the third convex portion is provided in a frame shape in the periphery of the second convex portions that are arranged in a line in the periphery of the first region. Therefore, the continuing third convex portion is arranged at positions of the respective sides of the frame shape so as to face the second convex portions that are aligned in a line. Therefore, it is possible to reduce the difference in the density of the material of the second light transmitting layer per unit volume between the region in which the second convex portions are arranged and the third convex portion is arranged at the positions of the respective sides of the frame shape. 
     APPLICATION EXAMPLE 4 
     In the lens array substrate according to the application example, it is preferable that the concave portions, the first convex portions, and the second convex portions are arranged at substantially the same arrangement pitch in a first direction and a second direction that intersects the first direction, and that the width of a portion of the third convex portion in the first direction and the width of a portion of the third convex portion in the second direction are equal to or less than ½ of the arrangement pitch. 
     According to the configuration of this application example, the second convex portions are arranged in the first direction and the second direction at substantially the same arrangement pitch, and the width of the third convex portion, which is arranged in the frame shape in the periphery thereof, in the first direction and the second direction is equal to or less than ½ of the arrangement pitch of the second convex portions. Therefore, since the second convex portions that are aligned in a line at substantially the same arrangement pitch and the third convex portion that continues with a width of equal to or less than ½ of the arrangement pitch are arranged at the positions of the respective sides of the frame shape of the third convex portion so as to face each other, it is possible to further reduce the difference in the density of the material of the second light transmitting layer per unit volume between the region in which the second convex portions are arranged and the region in which the third convex portion is arranged. 
     APPLICATION EXAMPLE 5 
     In the lens array substrate according to the application example, the diameter of the second convex portions may be smaller than the diameter of the first convex portions. 
     According to the configuration of this application example, the dummy lens that is formed by covering the second convex portions with the second light transmitting layer is arranged so as to overlap the light shielding portion in a plane. Therefore, light that is incident on the lens array substrate is not transmitted through the dummy lens. For this reason, since the diameter of the second convex portions is smaller than the diameter of the first convex portions, a difference in the properties of the dummy lenses from those of the lenses that are arranged in the first region does not affect light that is transmitted through the lens array substrate. 
     APPLICATION EXAMPLE 6 
     According to this application example, there is provided an electrooptical device including: a first substrate that includes a plurality of switching elements, each of which is provided for each pixel; a second substrate that includes the lens array substrate according to any one of the aforementioned application examples and is arranged so as to face the first substrate; and an electrooptical layer that is arranged between the first substrate and the second substrate, in which the concave portions and the first convex portions are arranged so as to overlap a region of the pixels in a plane. 
     According to the configuration of this application example, the electrooptical device is provided with the first substrate that includes switching elements, the second substrate that is arranged so as to face the first substrate, and the electrooptical layer that is arranged between the first substrate and the second substrate. Since the second substrate includes the lens array substrate according to the aforementioned application examples, the flatness of the surface of the second substrate is enhanced, and the lens that is formed of the first convex portions of the second lens layer and has uniform properties is arranged so as to overlap the region of pixels in a plane. In doing so, it is possible to provide an electrooptical device capable of providing bright display and excellent display quality. 
     APPLICATION EXAMPLE 7 
     According to this application example, there is provided an electronic apparatus including: the electrooptical device according to the aforementioned application examples. 
     According to the configuration of this application example, it is possible to provide an electronic apparatus with bright display and excellent display quality. 
     APPLICATION EXAMPLE 8 
     According to this application example, there is provided a method of manufacturing a lens array substrate including: forming a plurality of concave portions in a first region on a first surface of a substrate; forming, on the substrate, a first lens layer of a material with an optical refraction index difference from that of the substrate so as to cover the first surface and fill the plurality of concave portions; forming a first light transmitting layer so as to cover the first lens layer; forming a light shielding portion in a second region surrounding the first region on the first light transmitting layer; forming a second lens layer so as to cover the first light transmitting layer and the light shielding portion; forming a photosensitive material layer so as to cover the second lens layer; performing patterning for forming a plurality of first island-shaped sections in the first region so as to overlap the respective concave portions in a plane, a plurality of second island-shaped sections arranged in a line in the second region so as to overlap the light shielding portion in a plane and surround the plurality of first island-shaped sections, and a frame-shaped section that is arranged in a frame shape so as to surround the plurality of second island-shaped sections by exposing the photosensitive material layer to light and cutting the photosensitive material layer; performing heat treatment for heating the plurality of first island-shaped sections, the plurality of second island-shaped sections, and the frame-shaped section; performing anisotropic etching on the plurality of first island-shaped sections, the plurality of second island-shaped sections, the frame-shaped section, and the second lens layer to form, on the surface of the second lens layer, a plurality of first convex portions that reflects the shapes of the plurality of first island-shaped sections, a plurality of second convex portions that reflects the shapes of the plurality of second island-shaped sections, and a third convex portion that reflects the shape of the frame-shaped section; removing a peripheral edge of the third convex portion from the side of the surface of the second lens layer by a predetermined thickness; forming a second light transmitting layer of a material with an optical refraction index difference from that of the second lens layer so as to cover the second lens layer; and performing flattening processing of polishing and flattening the surface of the second light transmitting layer. 
     In the manufacturing method according to this application example, the first island-shaped sections and the second island-shaped sections are formed by cutting the photosensitive material layer in the patterning process, the first island-shaped sections and the second island-shaped sections are formed into lens shapes in the heat treatment process, and the first island-shaped sections in the lens shape and the second island-shaped sections in the lens shape are transferred to the second lens layer in the etching process. In the etching process, the amount of removal is larger in the outermost periphery than the inside thereof. However, the second island-shaped sections are arranged in the periphery of the first island-shaped sections. Therefore, it is possible to reduce the differences in shapes of the first convex portions that reflect the shapes of the first island-shaped sections as compared with a case in which the second island-shaped sections are not provided. In doing so, it is possible to uniformize the properties of the lenses that are arranged in the first region and are formed of the first convex portions and the second light transmitting layer in the second lens layer that reflects the shapes of the first island-shaped sections. 
     Since the diameter of the second island-shaped sections that are arranged so as to overlap the light shielding portion in a plane is smaller than the diameter of the first island-shaped sections due to the light reflected by the light shielding portion in the patterning process, the diameter of the second convex portions that are formed so as to reflect the shapes of the second island-shaped sections in the etching process is smaller than the diameter of the first convex portions that are formed so as to reflect the shapes of the first island-shaped sections. For this reason, a difference in the density of the material of the second light transmitting layer per unit volume occurs at a portion at which the first convex portions and the second convex portions are adjacent to each other when the surface of the second light transmitting layer that reflects the shapes of the first convex portions and the shapes of the second convex portions in the flattening process. Since the third convex portion is arranged in the periphery of the second convex portions, a difference in the density of the material of the second light transmitting layer occurs at a portion at which the second convex portions and the third convex portion are adjacent to each other when the surface of the second light transmitting layer is flattened. Here, since the second convex portions that are arranged in the periphery of the first convex portions are arranged in a line in this application example, it is possible to further reduce the difference in the density of the material of the second light transmitting layer per unit volume between the first region in which the first convex portions are arranged and the region in which the second convex portions are arranged as compared with a case in which the second convex portions are arranged in a plurality of lines. In addition, since the peripheral edge of the third convex portion is removed from the side of the surface of the second lens layer by the predetermined thickness, it is possible to reduce the difference in the density of the second light transmitting layer per unit volume between the region in which the second convex portions are arranged and the region in which the third convex portion is arranged. In doing so, it is possible to reduce the number of processes due to a decrease in amount of polishing in the flattening processing and to thereby enhance productivity of the lens array substrate. In addition, it is possible to enhance the flatness of the surface of the lens array substrate (second light transmitting layer). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a plan view schematically showing a configuration of a liquid crystal device according to an embodiment. 
         FIG. 2  is an equivalent circuit diagram showing an electrical configuration of the liquid crystal device according to the embodiment. 
         FIG. 3  is a sectional view schematically showing the configuration of the liquid crystal device according to the embodiment. 
         FIGS. 4A and 4B  are diagrams schematically showing a configuration of a microlens array substrate according to the embodiment. 
         FIGS. 5A to 5E  are diagrams schematically showing a method of manufacturing the microlens array substrate according to the embodiment. 
         FIGS. 6A to 6C  are diagrams schematically showing the method of manufacturing the microlens array substrate according to the embodiment. 
         FIGS. 7A to 7C  are diagrams schematically showing the method of manufacturing the microlens array substrate according to the embodiment. 
         FIGS. 8A to 8C  are diagrams schematically showing the method of manufacturing the microlens array substrate according to the embodiment. 
         FIGS. 9A and 9B  are diagrams schematically showing the method of manufacturing the microlens array substrate according to the embodiment. 
         FIG. 10  is a diagram schematically showing a configuration of a projector as an electronic apparatus according to the embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, a description will be given of an embodiment that realizes the invention with reference to drawings. The drawings used are appropriately shown in an enlarged, contracted, or exaggerated manner so as to show portions to be described in a recognizable state. In addition, components other than those necessary for illustration may be omitted in the drawings in some cases. 
     In the following embodiment, the description “on the substrate” represents an arrangement in which something is in contact with the top of the substrate, an arrangement in which something is arranged above the substrate with another component therebetween, and such an arrangement in which a portion of something is in contact with the top of the substrate and another portion thereof is arranged with another component therebetween, for example. 
     Electrooptical Device 
     In this embodiment, an active matrix-type liquid crystal device provided with thin film transistors (TFTs) as switching elements of pixels will be exemplified and described as an electrooptical device. The liquid crystal device can be suitably used as a light modulation element (liquid crystal light valve) in a projection-type display apparatus (projector) which will be described later, for example. 
     First, a description will be given of a liquid crystal device as an electrooptical device according to the embodiment with reference to  FIGS. 1, 2, and 3 .  FIG. 1  is a plan view schematically showing a configuration of a liquid crystal device according to the embodiment.  FIG. 2  is an equivalent circuit diagram showing an electrical configuration of the liquid crystal device according to the embodiment.  FIG. 3  is a sectional view schematically showing the configuration of the liquid crystal device according to the embodiment. Specifically,  FIG. 3  is a schematic sectional view taken along line III-III in  FIG. 1 . 
     As shown in  FIGS. 1 and 3 , a liquid crystal device  1  according to the embodiment includes an element substrate  20  as the first substrate, a facing substrate  30  as the second substrate that is arranged so as to face the element substrate  20 , a sealing material  42 , and a liquid crystal layer  40  as an electrooptical layer. As shown in  FIG. 1 , the element substrate  20  is larger than the facing substrate  30 , and the element substrate  20  and the facing substrate  30  are bonded to each other via the sealing material  42  that is arranged in a frame shape along the edge of the facing substrate  30 . 
     The liquid crystal layer  40  is formed of liquid crystal with positive or negative dielectric anisotropy, which is sealed in a space surrounded by the element substrate  20 , the facing substrate  30 , and the sealing material  42 . The sealing material  42  is made of an adhesive of thermosetting or ultraviolet curable epoxy resin, for example. A spacer (not shown) for constantly maintaining a gap between the element substrate  20  and the facing substrate  30  is mixed into the sealing material  42 . 
     Light shielding portions  22  and  26  that are provided on the element substrate  20  and a light shielding portion  31  that is provided on the facing substrate  30  are arranged inside the sealing material  42  arranged in a frame shape. The light shielding portion  31  has a frame shape, and the light shielding portions  22  and  26  have frame-shaped peripheral edges that overlap the light shielding portion  31  in plan view. The inside of the light shielding portion  31  in the frame shape and the portions of the light shielding portions  22  and  26  in the frame shapes correspond to a display region E as the first region in which a plurality of pixels P are aligned. The pixels P have a polygonal plane shape. The pixels P have a substantially rectangular shape, for example, and are aligned in a matrix arrangement. 
     The display region E in the liquid crystal device  1  is a region that substantially contributes to display. The light shielding portions  22  and  26  on the element substrate  20  are provided in a grid arrangement, for example, in the display region E so as to section opening regions of the plurality of pixels P in a plane. The periphery of the display region E overlaps the light shielding portion  31  provided in the frame shape or the portions of the light shielding portions  22  and  26  in the frame shapes in plan view, and corresponds to a parting region BS as the second region that does not substantially contribute to display (see  FIG. 3 ). 
     On a side, which is opposite to the display region E, of the sealing material  42  that is formed along a first side of the element substrate  20 , a data line driving circuit  51  and a plurality of external connection terminals  54  are provided along the first side. In addition, an inspection circuit  53  is provided on the side of the display region E of the sealing material  42  along a second side that faces the first side. Furthermore, scanning line driving circuits  52  are provided inside the sealing material  42  along the other two sides that perpendicularly intersect the two sides and face each other. 
     On the side of the display region E of the sealing material  42  along the second side, along which the inspection circuit  53  is provided, a plurality of wirings  55  that connect the two scanning line driving circuits  52  are provided. These wirings that are connected to the data line driving circuit  51  and the scanning line driving circuits  52  are connected to the plurality of external connection terminals  54 . In addition, upper and lower conductive sections  56  for establishing electrical conduction between the element substrate  20  and the facing substrate  30  are provided at the corners of the facing substrate  30 . The arrangement of the inspection circuit  53  is not limited thereto, and the inspection circuit  53  may be provided at a position along the inside of the sealing material  42  between the data line driving circuit  51  and the display region E. 
     In the following description, the direction along the first side along which the data line driving circuit  51  is provided will be referred to as an X direction that serves as the first direction, and the direction along the other two sides that perpendicularly intersect the first side and face each other will be referred to as a Y direction that serves as the second direction. The X direction is a direction along line III-III in  FIG. 1 . The light shielding portions  22  and  26  are provided in the grid arrangement along the X direction and the Y direction. The opening regions of the pixels P are sectioned in the grid arrangement by the light shielding portions  22  and  26  and are aligned in the matrix arrangement in the X direction and the Y direction. 
     In addition, a direction that perpendicularly intersects the X direction and the Y direction and is directed upward in  FIG. 1  will be referred to as a Z direction. In this specification, a view from a normal line direction (Z direction) of the surface of the liquid crystal device  1  on the side of the facing substrate  30  will be referred to as a “plan view”. 
     As shown in  FIG. 2 , scanning lines  2  and data lines  3  are formed in the display region E so as to intersect each other, and the pixels P are provided so as to correspond to the intersection between the scanning lines  2  and the data lines  3 . The respective pixels P are provided with pixel electrodes  28  and TFTs  24  as switching elements. 
     Source electrodes (not shown) of the TFTs  24  are electrically connected to the data lines  3  that extend from the data line driving circuit  51 . Image signals (data signals) S 1 , S 2 , . . . Sn are sequentially supplied from the data line driving circuit  51  (see  FIG. 1 ) to the data lines  3 . Gate electrodes (not shown) of the TFTs  24  are parts of the scanning lines  2  that extend from the scanning line driving circuits  52 . Scanning signals G 1 , G 2 , . . . , Gm are sequentially supplied from the scanning line driving circuits  52  to the scanning lines  2 . Drain electrodes (not shown) of the TFTs  24  are electrically connected to the pixel electrodes  28 . 
     The image signals S 1 , S 2 , . . . , Sn are written in the pixel electrodes  28  via the data lines  3  at a predetermined timing by turning the TFTs  24  into an ON state only during a predetermined period of time. The image signals in the predetermined level, which have been written in the liquid crystal layer  40  via the pixel electrodes  28  as described above, are held for a predetermined period of time in liquid crystal capacitors that are formed along with a common electrode  34  (see  FIG. 3 ) that is provided on the facing substrate  30 . 
     In order to prevent leakage of the held image signals S 1 , S 2 , . . . , Sn, storage capacitors  5  are formed between capacitance lines  4  that are formed along the scanning lines  2  and the pixel electrodes  28  and are arranged in parallel with the liquid crystal capacitors. If a voltage signal is applied to the liquid crystal of the respective pixels P as described above, the orientation state of the liquid crystal varies depending on the level of the applied voltage. In doing so, light that has been incident on the liquid crystal layer  40  (see  FIG. 3 ) is modulated, and it becomes possible to perform gradation display. 
     The liquid crystal that forms the liquid crystal layer  40  modulates the light in response to variations in orientation and an order of a group of molecules depending on the level of applied voltage and enables gradation display. In the case of a normally white mode, for example, transmittance of the incident light decreases in accordance with the applied voltage in units of respective pixels P. In a case of a normally black mode, the transmittance of the incident light increases in accordance with the applied voltage in units of the respective pixels P, and light with contrast in accordance with the image signals is output from the liquid crystal device  1  as a whole. 
     As shown in  FIG. 3 , the element substrate  20  includes a substrate  21 , a light shielding portion  22 , an insulating layer  23 , the TFTs  24 , an insulating layer  25 , a light shielding portion  26 , an insulating layer  27 , the pixel electrodes  28 , and an orientation film  29 . The substrate  21  is made of a light transmitting material such as glass or quartz. 
     The light shielding portion  22  is provided on the substrate  21 . The light shielding portion  22  is formed into a grid arrangement so as to overlap the light shielding portion  26  in the upper layer in plan view. The light shielding portion  22  and the light shielding portion  26  are formed of metal or a metal compound, for example. The light shielding portion  22  and the light shielding portion  26  are arranged so as to interpose the TFTs  24  therebetween in a thickness direction (Z direction) of the element substrate  20 . The light shielding portion  22  overlaps at least a channel region of the TFTs  24  in plan view. 
     It is possible to suppress light that is incident on the TFTs  24  and to thereby suppress erroneous operations due to an increase in optical leakage current or light at the TFTs  24  by providing the light shielding portion  22  and the light shielding portion  26 . A region, which overlaps the light shielding portion  22  and the light shielding portion  26  in plan view, of the region of the pixels P corresponds to a light shielding region S through which no light is transmitted. A region surrounded by the light shielding portion  22  (inside the opening  22   a ) and a region surrounded by the light shielding portion  26  (inside the opening  26   a ) overlap each other in plan view and correspond to an opening region T, through which light is transmitted, in the region of the pixels P. 
     The insulating layer  23  is provided so as to cover the substrate  21  and the light shielding portion  22 . The insulating layer  23  is made of an inorganic material such as SiO 2 . 
     The TFTs  24  are provided on the insulating layer  23  and are arranged in a region in which the TFTs  24  overlap the light shielding portion  22  and the light shielding portion  26  in plan view. The TFTs  24  are switching elements that drive the pixel electrodes  28 . The TFTs  24  are formed of semiconductor layers, the gate electrodes, the source electrodes, and the drain electrodes that are not shown in the drawing. In each semiconductor layer, a source region, a channel region, and a drain region are formed. A lightly doped drain (LDD) region may be formed at an interface between the channel region and the source region or between the channel region and the drain region. 
     Each gate electrode is formed via a portion (gate insulating film) of the insulating layer  25  in a region, in which the gate electrode overlaps the channel region of the semiconductor layer in plan view, on the element substrate  20 . Though not shown in the drawing, the gate electrode is electrically connected to a scanning line arranged on the side of a lower layer via a contact hole, and ON/OFF states of each TFT  24  are controlled by an application of a scanning signal. 
     The insulating layer  25  is provided so as to cover the insulating layer  23  and the TFTs  24 . The insulating layer  25  is made of an inorganic material such as SiO 2 . The insulating layer  25  includes a gate insulating film for insulating between the semiconductor layers and the gate electrodes of the TFTs  24 . The insulating layer  25  alleviates surface unevenness that is caused by the TFTs  24 . The light shielding portion  26  is provided on the insulating layer  25 . In addition, the insulating layer  27  made of an inorganic material is provided so as to cover the insulating layer  25  and the light shielding portion  26 . 
     The pixel electrode  28  is provided on the insulating layer  27  so as to correspond to the pixels P. The pixel electrodes  28  are arranged in a region in which the pixel electrodes  28  overlap the opening  22   a  of the light shielding portion  22  and the opening  26   a  of the light shielding portion  26  in plan view. The pixel electrodes  28  are made of transparent conductive films of indium tin oxide (ITO) or indium zinc oxide (IZO). The orientation film  29  is provided so as to cover the pixel electrodes  28 . The liquid crystal layer  40  is sealed between the orientation film  29  on the side of the element substrate  20  and an orientation film  35  on the side of the facing substrate  30 . 
     Though not shown in the drawing, electrodes, wirings, and relay electrodes for supplying electrical signals to the TFTs  24  and capacitance electrodes configuring the storage capacitors  5  (see  FIG. 2 ) are provided in the region in which these components overlap the light shielding portion  22  and the light shielding portion  26  in plan view. The light shielding portion  22  and the light shielding portion  26  may be configured to include the electrodes, the wirings, the relay electrodes, the capacitance electrodes, and the like. 
     The facing substrate  30  includes a microlens array substrate  10  as a lens array substrate which will be described later, the common electrode  34 , and the orientation film  35 . The microlens array substrate  10  includes two-stage microlenses, each of which is formed of a first microlens ML 1  and a second microlens ML 2  for each pixel P. The common electrode  34  is provided so as to cover the microlens array substrate  10  (optical path length adjustment layer  32 ). The common electrode  34  is formed so as to be laid across the plurality of pixels P. The common electrode  34  is made of a transparent conductive film of indium tin oxide (ITO) or indium zinc oxide (IZO), for example. The orientation film  35  is provided so as to cover the common electrode  34 . 
     Microlens Array Substrate 
     Next, a description will be given of the microlens array substrate according to the embodiment with reference to  FIGS. 3 to 4B .  FIGS. 4A and 4B  are diagrams schematically showing a configuration of the microlens array substrate according to the embodiment. Specifically,  FIG. 4A  is a sectional view schematically showing the configuration of the microlens array substrate, and  FIG. 4B  is a plan view schematically showing the configuration of the microlens array substrate.  FIG. 4A  corresponds to a partially enlarged view of  FIG. 3 , and the vertical direction (Z direction) is inverted from that in  FIG. 3 .  FIG. 4B  is a schematic plan view of the microlens array substrate  10  when viewed from the side of the second lens layer  15  in a state in which the optical path length adjustment layer  32  is removed. 
     As shown in  FIG. 4A , the microlens array substrate  10  includes a substrate  11 , a first lens layer  13 , an intermediate layer  14  as the first light transmitting layer, a light shielding portion  31 , a second lens layer  15 , and an optical path length adjustment layer  32  as the second light transmitting layer. In  FIG. 4B , the region with hatched lines directed toward the lower right side corresponds to a region in which the light shielding portion  31  is provided, namely the parting region BS. 
     The substrate  11  shown in  FIG. 4A  is made of a light transmitting inorganic material such as glass or quartz. The surface, which faces the liquid crystal layer  40  (see  FIG. 3 ), of the substrate  11  will be referred to as a surface  11   a  as the first surface. The substrate  11  includes a plurality of concave portions  12  that are formed in the display region E on the surface  11   a . The respective concave portions  12  are provided for the respective pixels P and are aligned in a matrix arrangement in plan view in the display region E (see  FIG. 4B ). It is preferable that the concave portions  12  that are adjacent to each other in the X direction and the Y direction are in contact with each other. The concave portions  12  have a sectional shape with a curved surface at the central portion and an inclined surface (so-called tapered surface) at peripheral edge surrounding the curved surface. 
     The first lens layer  13  is formed to have a thickness that is thicker than the depth of the concave portions  12  so as to cover the surface  11   a  of the substrate  11  and fill the concave portions  12 . The first lens layer  13  has a light transmitting property and is made of a material with an optical refraction index difference from that of the substrate  11 . According to the embodiment, the first lens layer  13  is made of an inorganic material with a higher optical refraction index than that of the substrate  11 . As such an inorganic material, SiON, Al 2 O 3 , and the like are exemplified. 
     The first microlenses ML 1  with a convex shape that is curved toward the side of the substrate  11  are configured by filling the respective concave portions  12  with the material that forms the first lens layer  13 . Therefore, the respective first microlenses ML 1  are provided so as to correspond to the pixels P. The plurality of first microlenses ML 1  configure a microlens array in a first stage. The first lens layer  13  has a surface that is flat and substantially parallel to the surface  11   a  of the substrate  11 . 
     Light that is incident on the central portion (curved surface) of each first microlens ML 1  from the substrate  11  is collected toward the center (a focal point of the curved surface) of the first microlens ML 1  due to a difference in optical refraction indexes of the substrate  11  and the first lens layer  13  (positive refractive power). In addition, light that is incident on the peripheral edges of each first microlens ML 1  is refracted to the side of the center of each first microlens ML 1  at substantially the same angle in a case of substantially the same incident angle. Therefore, excessive refraction of the incident light is suppressed and variations in angle of the light that is incident on the liquid crystal layer  40  are suppressed as compared with a case in which each first microlens ML 1  is entirely formed of a curved surface. 
     The intermediate layer  14  is formed so as to cover the first lens layer  13 . The intermediate layer  14  has a light transmitting property and is made of an inorganic material with substantially the same optical refraction index as that of the substrate  11 , for example. As such an inorganic material, SiO 2  and the like are exemplified. The intermediate layer  14  has a function of adjusting a distance from each first microlens ML 1  to each second microlens ML 2  to a desired value. Therefore, the thickness of the intermediate layer  14  is appropriately set based on optical conditions such as a focal distance of each first microlens ML 1  in accordance with a wavelength of light and the like. In addition, the intermediate layer  14  may be formed of the same material as that of the first lens layer  13  or may be formed of the same material as that of the second lens layer  15 . 
     The light shielding portion  31  is formed on the intermediate layer  14 . The light shielding portion  31  is formed of metal such as aluminum (Al), metal oxide, or the like. The light shielding portion  31  is formed in a frame shape in the parting region BS that surrounds the display region E as described above. The light that is incident on the parting region BS is blocked or reflected by the light shielding portion  31 . 
     The second lens layer  15  is formed so as to cover the intermediate layer  14  and the light shielding portion  31 . The second lens layer  15  includes convex portions  16  as the plurality of first convex portions, convex portions  17  as the plurality of second convex portions, and a convex portion  18  as the third convex portion that are formed on the opposite side to the substrate  11  (the side of the liquid crystal layer  40  shown in  FIG. 3 ). The convex portions  16  and the convex portions  17  have a sectional shape of a curved surface such as a substantially oval spherical surface. The convex portion  18  has an arc sectional shape that corresponds to substantially a half of the substantially oval spherical shape, for example. 
     As shown in  FIG. 4B , the respective convex portions  16  are provided so as to correspond to the pixels P. Therefore, the convex portions  16  are aligned in a matrix arrangement in the display region E so as to overlap the respective concave portions  12  in plan view. An arrangement pitch of the convex portions  16  in the X direction and the Y direction is substantially the same as the arrangement pitch of the concave portions  12  in the X direction and the Y direction. In this embodiment, the convex portions  16  that are adjacent in the X direction and the Y direction are in contact with each other, and the arrangement pitch of the convex portions  16  in the X direction and the Y direction is the same as the diameter D 1  of the convex portions  16 . 
     The convex portions  17  and the convex portion  18  are provided in the parting region BS. The convex portions  17  are arranged in a line so as to surround the convex portions  16  that are aligned in the matrix arrangement. In other words, the convex portions  17  are arranged in a line in each of the X direction and the Y direction in the periphery of the display region E. The arrangement pitch of the convex portions  17  is substantially the same as the arrangement pitch (D 1 ) of the convex portions  16 . A diameter D 2  of the convex portions  17  in the X direction and the Y direction is smaller than the diameter D 1  of the convex portions  16 . The diameter D 2  of the convex portions  17  is smaller than the diameter D 1  of the convex portions  16  by about 4% to about 6%, for example. 
     The convex portion  18  is provided in a frame shape in the periphery of the convex portions  17  that are arranged in a line in each of the X direction and the Y direction. In other words, the convex portion  18  has a planar shape in which a pair of portions that extend in the X direction and a pair of portions that extend in the Y direction are connected to each other. The portions of the convex portion  18  that extend in the X direction and the portions of the convex portion  18  that extend in the Y direction have the same width W. The width W of the portions that extend in the X direction and the portions that extend in the Y direction of the convex portion  18  is equal to or less than ½ of the arrangement pitch of the convex portions  16 . 
     Returning to  FIG. 4A , the second lens layer  15  is formed of a base lens layer  15   a  and the superficial lens layer  15   b  from the side of the intermediate layer  14 . The base lens layer  15   a  includes a plurality of convex portions  16   a , convex portions  17   a  that are arranged in a line in the periphery of the convex portions  16   a , and a convex portion  18   a  that is arranged in a frame shape in the periphery of the convex portions  17   a . In addition, it is possible to substantially ignore refraction and reflection of light that is incident on the second lens layer  15  at the boundary between the base lens layer  15   a  and the superficial lens layer  15   b.    
     The convex portions  16 , the convex portions  17 , and the convex portion  18  of the second lens layer  15  (superficial lens layer  15   b ) are formed in such a manner that the shapes of the convex portions  16   a , the convex portions  17   a , and the convex portion  18   a  are enlarged, by laminating the superficial lens layer  15   b  on the base lens layer  15   a . Therefore, the diameter of the convex portions  16   a  is smaller than the diameter D 1  of the convex portions  16 , the diameter of the convex portions  17   a  is smaller than the diameter D 2  of the convex portions  17 , and the width of the convex portion  18   a  is smaller than the width W of the convex portion  18 . 
     The second lens layer  15  (superficial lens layer  15   b ) includes a flattened section  19 , the height of which from the intermediate layer  14  is lower than the height of the convex portion  18 , which has a substantially flat surface, outside the convex portion  18 . In  FIG. 4B , the region with the hatched lines directed toward the lower left side corresponds to a region in which the flattened section  19  is provided. The flattened section  19  is provided at the peripheral edge of the second lens layer  15  so as to surround the convex portion  18  in the frame shape. 
     When the height of the uppermost portion of the convex portion  18  with respect to the bottom between the convex portions  17  and the convex portion  18  is assumed to be H 1  and the level difference between the uppermost portion of the convex portion  18  and the flattened section  19  is assumed to be H 2  as shown in  FIG. 4A , the level difference H 2  is smaller than ½ of the height H 1  of the convex portion  18 , for example. In other words, the height of the flattened section  19  from the intermediate layer  14  is greater than ½ of the height H 1  of the convex portion  18 . In this embodiment, the height H 1  of the convex portion  18  is substantially the same as the height of the convex portions  16  and the convex portions  17 . 
     The base lens layer  15   a  includes a flattened section  19   a  with a substantially flat surface in the periphery of the convex portion  18 . The flattened section  19  of the second lens layer  15  (superficial lens layer  15   b ) is formed so as to reflect the flattened section  19   a  by laminating the superficial lens layer  15   b  on the base lens layer  15   a.    
     The second lens layer  15  (the base lens layer  15   a  and the superficial lens layer  15   b ) includes substantially the same optical refraction index as that of the first lens layer  13 , for example, and is formed of the same material as that of the first lens layer  13 . The base lens layer  15   a  and the superficial lens layer  15   b  are formed of the same material and have the same optical refraction index. 
     The optical path length adjustment layer  32  is formed so as to fill between the convex portions  16 , between the convex portions  16  and the convex portions  17 , between the convex portions  17  and the convex portion  18 , and the flattened section  19 , cover the second lens layer  15  (superficial lens layer  15   b ), and be thicker than the height H 1  of the convex portion  18 . The optical path length adjustment layer  32  has a light transmitting property and is made of an inorganic material with a lower optical refraction index than that of the second lens layer  15 , for example. As such an inorganic material, SiO 2  is exemplified. 
     The second microlenses ML 2  with the convex shape that are curved toward the opposite side (the side of the liquid crystal layer  40  shown in  FIG. 3 ) to the substrate  11  are configured by covering the convex portions  16  with the optical path length adjustment layer  32 . The respective second microlenses ML 2  are provided so as to correspond to the pixels P. The plurality of second microlenses ML 2  configure a microlens array in the second stage. Light that is incident on the optical path length adjustment layer  32  from each second microlens ML 2  is collected toward the side of the center of each second microlens ML 2  due to a difference in optical refraction indexes of the second lens layer  15  and the optical path length adjustment layer  32  (positive refractive power). 
     In addition, dummy microlenses MLd with a convex shape that are curved toward the opposite side to the substrate  11  are configured by covering the convex portions  17  with the optical path length adjustment layer  32 . The dummy microlenses MLd are for suppressing variations in shapes of the second microlenses ML 2  that are arranged in the display region E as will be described later. The dummy microlenses MLd are arranged in the parting region BS so as to overlap the light shielding portion  31  in plan view. Therefore, light that is incident on the dummy microlenses MLd is not transmitted through the microlens array substrate. For this reason, the dummy microlenses MLd do not contribute to display of the liquid crystal device  1 . 
     The optical path length adjustment layer  32  has a function of adjusting the distance from the second microlenses ML 2  to the light shielding portion  26  (see  FIG. 3 ) to a desired value. Therefore, the thickness of the optical path length adjustment layer  32  is appropriately set based on optical conditions such as a focal distance of the second microlenses ML 2  in accordance with a wavelength of light and the like. 
     The optical path length adjustment layer  32  is formed of a first optical path length adjustment layer  32   a  and a second optical path length adjustment layer  32   b  that are laminated from the side of the second lens layer  15 . The first optical path length adjustment layer  32   a  has a substantially flat surface. The first optical path length adjustment layer  32   a  has a slit  33  that extends from a valley portion (boundary) between adjacent second microlenses ML 2  to the side of the liquid crystal layer  40  (see  FIG. 3 ). The slit  33  is provided so as to surround the second microlenses ML 2  in plan view. 
     The slit  33  sections the first optical path length adjustment layer  32   a  into portions that correspond to the respective second microlenses ML 2 . The materials of the adjacent first optical path length adjustment layers  32   a  that are sectioned by the slit  33  do not have a bonded relationship while being in contact with each other. Therefore, the slit  33  functions as an interface between the materials of the adjacent first optical path length adjustment layers  32   a , and light that is incident on the slit  33  is reflected. 
     The second optical path length adjustment layer  32   b  is formed so as to be laminated on the first optical path length adjustment layer  32   a . The second optical path length adjustment layer  32   b  has a substantially flat surface. The slit  33  discontinues at the boundary between the first optical path length adjustment layer  32   a  and the second optical path length adjustment layer  32   b . Therefore, the second optical path length adjustment layer  32   b  does not have the slit  33 . 
     Returning to  FIG. 3 , the liquid crystal device  1  according to the embodiment is configured such that light that is generated by a light source, for example, is incident form the side of the facing substrate  30  (substrate  11 ) provided with the microlens array substrate  10 . Light L 1 , which is incident on the center of each first microlens ML 1  in the normal direction of the surface of the facing substrate  30  (substrate  11 ), as a portion of incident light travels straight, is incident on the center of each second microlens ML 2 , directly travels straight, is transmitted through the opening region T of each pixel P, and is then output to the side of the element substrate  20 . 
     In the following description, the normal direction of the surface of the facing substrate  30  (substrate  11 ) will simply be referred to as a “normal direction”. The “normal direction” is a direction along the Z direction in  FIG. 3 , and is substantially the same as the normal direction of the element substrate  20  (substrate  21 ). 
     Light L 2  that is incident on an end of each first microlens ML 1  in the normal direction is blocked by the light shielding portion  26  as represented by the broken line if the light L 2  directly travels straight. However, the light L 2  is refracted toward the side of the center of the first microlens ML 1  due to the difference in the optical refraction indexes of the substrate  11  and the first lens layer  13  (positive refractive power) and is then incident on each second microlens ML 2 . Then, the light L 2  that is incident on the second microlens ML 2  is further refracted toward the center of the second microlens ML 2  due to the difference in the optical refraction indexes of the second lens layer  15  and the optical path length adjustment layer  32  (positive refractive power), is transmitted through the opening region T of each pixel P, and is then output to the side of the element substrate  20 . 
     Light L 3  that is incident on the end of each first microlens ML 1  obliquely with respect to the normal direction and is incident toward the outside of the center of the first microlens ML 1  is deviated toward the outside of the second microlens ML 2  if the light L 3  directly travels straight. However, the light L 3  is refracted toward the side of the center due to the first microlens ML 1  and is then incident on the second microlens ML 2 . The light L 3  that is incident on the second microlens ML 2  is blocked by the light shielding portion  26  if the light L 3  directly travels straight. However, the light L 3  is further refracted toward the side of the center of the second microlens ML 2 , is transmitted through the opening region T of each pixel P, and is then output to the side of the element substrate  20 . 
     Light L 4  that is incident on the end of the first microlens ML 1  obliquely with respect to the normal direction and is incident toward the center from the outside of the first microlens ML 1  is further inclined with respect to the normal direction due to refraction, intersects a line (represented by a one-dotted chain line in  FIG. 3 ) that connects the center of the first microlens ML 1  and the center of the second microlens ML 2 , and is then incident on the second microlens ML 2 . The light L 4  that is incident on the second microlens ML 2  is blocked by the light shielding portion  26  if the light L 4  directly travels straight. However, the light L 4  is refracted by the second microlens ML 2 , is returned to the side of the center, is less inclined with respect to the normal direction, is transmitted through the opening region T of the pixel P, and is then output to the side of the element substrate  20 . 
     Light L 5  that is incident on the end of the first microlens ML 1  while being further inclined with respect to the normal direction and is incident from the center of the first microlens ML 1  toward the outside is output from the end of the second microlens ML 2  though the light L 5  is refracted by the first microlens ML 1  and the second microlens ML 2  toward the side of the center due to insufficient refraction. The light L 5  that is output from the second microlens ML 2  is blocked by the light shielding portion  26  if the light L 5  directly travels straight. However, the light L 5  is reflected by the slit  33 , is transmitted through the opening region T of the pixel P, and is then output to the side of the element substrate  20 . 
     Light L 6  that is incident on the end of the first microlens ML 1  while being further inclined with respect to the normal direction in the same manner as the light L 5  and is incident from the outside of the first microlens ML 1  toward the center is further inclined with respect to the normal direction, intersects a line (represented by a one-dotted chain line in  FIG. 3 ) that connects the center of the first microlens ML 1  and the second microlens ML 2 , and is then incident on the end of the second microlens ML 2 . The light L 6  that is output from the second microlens ML 2  is deviated toward the side of next pixel P if the light L 6  is insufficiently refracted and directly travels straight. However, the light L 6  is reflected by the slit  33 , is transmitted through the opening region T of the pixel P, and is then output to the side of the element substrate  20 . 
     According to the liquid crystal device  1 , it is possible to refract the light L 2 , the light L 3 , and the light L 4 , which are blocked in the light shielding region S in a case of directly traveling straight, to the side of the center of the opening region T of the pixel P due to effects of the first microlens ML 1  and the second microlens ML 2  provided in the two stages, and to transmit the light L 2 , the light L 3 , and the light L 4  through the opening region T as described above. In addition, it is possible to refract the light L 5  that is blocked in the light shielding region S even after being refracted by the first microlens ML 1  and the second microlens ML 2  in the two stages and the light L 6  that is deviated to the side of the next pixel P to the side of the center of the opening region T of the pixel P due to an effect of the slit  33  and to transmit the light L 5  and the light L 6  through the opening region T. As a result, it is possible to increase the intensity of light that is output from the side of the element substrate  20  and to thereby enhance the efficiency of utilizing the light. 
     Although the embodiment is configured such that the optical refraction index of the optical path length adjustment layer  32  is lower than the optical refraction index of the second lens layer  15 , another configuration is also applicable in which the optical refraction index of the optical path length adjustment layer  32  is higher than the optical refraction index of the second lens layer  15 . With such a configuration, the light that is incident o the second microlens ML 2  is diffused from the center of the second microlens ML 2  toward the outside due to the difference in the optical refraction indexes of the second lens layer  15  and the optical path length adjustment layer  32  (negative refractive power). Therefore, it is possible to reduce an angle of the light that is collected by the first microlens ML 1  and is inclined with respect to the normal direction by the second microlens ML 2  and to cause the angle to approach the normal direction. 
     If the liquid crystal device  1  is used as a liquid crystal light valve in a projector and a large part of light that is output from the liquid crystal device  1  is inclined with respect to the normal direction, an uptake angle of a projection lens is exceeded, vignetting occurs, and as a result, the efficiency of utilizing the light deteriorates in some cases. In such cases, a configuration is applicable in which the second microlenses ML 2  have negative refractive power. 
     Although the embodiment is configured such that the light shielding portion  31  is provided in the frame shape in the parting region BS, the light shielding portion  31  may have, in addition to the frame-shaped portion, a grid-shaped portion that overlaps the light shielding portion  22  and the light shielding portion  26  (see  FIG. 3 ) of the element substrate  20  in plan view in order to suppress light being incident on the TFTs  24 . However, the first optical path length adjustment layer  32   a  is provided with the slit  33  in the liquid crystal device  1 , and it is possible to reflect light, which is insufficiently refracted by the first microlens ML 1  and the second microlens ML 2  and travels toward the outside of the opening region T, by the slit  33 , to cause the light to be incident on the opening region T, and to thereby sufficiently suppress the light being incident on the TFTs  24 . 
     Furthermore, although the embodiment is configured such that the dummy microlenses MLd are provided only on the side of the second microlenses ML 2  (second lens layer  15 ), another configuration is also applicable in which the dummy microlenses are also provided on the side of the first microlenses ML 1 . 
     Method of Manufacturing Microlens Array Substrate 
     Next, a description will be given of a method of manufacturing the microlens array substrate  10  according to the embodiment.  FIGS. 5A to 9B  are diagrams schematically showing the method of manufacturing the microlens array substrate according to the embodiment. Each of  FIGS. 5A to 8C  corresponds to the sectional view schematically shown in  FIG. 4A . In addition,  FIGS. 9A and 9B  correspond to the plan view schematically shown in  FIG. 4B . 
     As shown in  FIG. 5A , a control film  70  that is made of an oxide film of SiO 2 , for example, is formed on the surface  11   a  of the light transmitting substrate  11  that is made of quartz, for example. The control film  70  is obtained by isotropic etching at a different etching rate from that for the substrate  11  and has a function of adjusting an etching rate in width directions (the X direction and the Y direction shown in  FIG. 4B ) with respect to an etching rate in a depth direction (Z direction) when the concave portions  12  are formed. 
     After the control film  70  is formed, the control film  70  is annealed at a predetermined temperature. The etching rate of the control film  70  varies depending on the temperature during the annealing. Therefore, it is possible to adjust the etching rate of the control film  70  by appropriately setting the temperature during the annealing. 
     Next, a mask layer  72  is formed on the control film  70 . Then, the mask layer  72  is patterned, and opening  72   a  are formed in the mask layer  72 . The positions of the centers of the openings  72   a  in a plane correspond to the centers of the formed concave portions  12 . Subsequently, the substrate  11  that is covered with the control film  70  is subjected to isotropic etching via the openings  72   a  in the mask layer  72 . Though not shown in the drawing, openings are formed in regions at which the openings overlap the openings  72   a  in the control film  70  are formed, and the substrate  11  is etched via the openings in this isotropic etching. 
     For the isotropic etching, such an etching solution (such as hydrofluoric acid solution) that the etching rate of the control film  70  becomes greater than the etching rate of the substrate  11  is used. In doing so, the amount of etching of the control film  70  per unit time becomes larger than the amount of etching of the substrate  11  per unit time in the isotropic etching. Therefore, the amounts of etching of the substrate  11  in the width directions become larger than the amount of etching in the depth direction with enlargement of the openings formed in the control film  70 . 
     The control film  70  and the substrate  11  are etched from the openings  72   a  in the isotropic etching, and the concave portions  12  are formed on the side of the surface  11   a  of the substrate  11  as shown in  FIG. 5B . By setting the etching rates as described above, the concave portions  12  are enlarged in the width directions than in the depth direction, and tapered oblique surfaces are formed in the peripheral edges of the concave portions  12 .  FIG. 5B  shows a state after the mask layer  72  and the control film  70  are removed. 
     In this process, the isotropic etching is performed until the concave portions  12  that are adjacent in the X direction and the Y direction are connected to each other. In addition, it is preferable that the isotropic etching is completed in a state in which the concave portions  12  that are adjacent in a diagonal line direction that intersects the X direction and the Y direction are separate from each other, that is, a state in which the surface  11   a  of the substrate  11  remains at each gap between the concave portions  12  that are adjacent in the diagonal line direction. 
     If the isotropic etching is performed until the concave portions  12  that are adjacent in the diagonal line direction are connected to each other, there is a concern that the mask layer  72  floats from the substrate  11  and peels off. If the isotropic etching is completed in the state in which the surface  11   a  of the substrate  11  remains at the gap between the adjacent concave portions  12 , it is possible to support the mask layer  72  until the isotropic etching is completed. In doing so, the planar shape of each concave portion  12  becomes a substantially rectangular shape with four rounded corners (see  FIG. 4B ). 
     Although the concave portions  12  including the tapered oblique surfaces at the peripheral edges are formed in the embodiment, the concave portions  12  may be formed so as to be entirely formed of curved surfaces without any tapered oblique surfaces at the peripheral edges thereof. In such a case, the control film  70  may not be provided when the concave portions  12  are formed. 
     Next, the first lens layer  13  is formed by depositing a light transmitting inorganic material with a higher optical refraction index than that of the substrate  11  so as to cover the substrate  11  on the side of the surface  11   a  and fill the concave portions  12  as shown in  FIG. 5C . The first lens layer  13  can be formed by using the CVD method, for example. Since the first lens layer  13  is formed so as to fill the concave portions  12 , the first lens layer  13  has a surface with unevenness that reflects unevenness caused by the concave portions  12  in the substrate  11 . 
     In addition, an alignment mark for positioning the first microlenses ML 1  and the second microlenses ML 2  and positioning the microlens array substrate  10  (facing substrate  30 ) and the element substrate  20  may be formed between the substrate  11  and the first lens layer  13 . The alignment mark is arranged in the parting region BS in which the light shielding portion  31  is formed in the process shown in  FIG. 5E . 
     Next, the first lens layer  13  is subjected to flattening processing as shown in  FIG. 5D . In the flattening processing, an upper surface is flattened by polishing and removing portions, in which unevenness is formed, on the upper side of the first lens layer  13  by using chemical mechanical polishing (CMP) processing, for example. Then, the first microlenses ML 1  are configured by filling the concave portions  12  with the material of the first lens layer  13 . 
     Next, the intermediate layer  14  is formed by depositing a light transmitting inorganic material with substantially the same optical refraction index as that of the substrate  11 , for example, so as to cover the first lens layer  13  as shown in  FIG. 5E . The intermediate layer  14  may be formed by using the CVD method, for example. Then, the light shielding portion  31  is formed of metal such as aluminum (Al) or metal oxide on the intermediate layer  14 . The light shielding portion  31  is formed in a frame shape in the periphery of the region in which the concave portions  12  are formed. The region that overlaps the light shielding portion  31  in plan view corresponds to the parting region BS, and the region that is surrounded by the parting region BS corresponds to the display region E. 
     Next, the base lens layer  15   a  is formed by depositing a light transmitting inorganic material with a higher optical refraction index than that of the substrate  11  so as to cover the intermediate layer  14  and the light shielding portion  31  as shown in  FIG. 6A . The base lens layer  15   a  can be formed by using the CVD method, for example. 
     Next, a resist layer  74  as a photosensitive material layer is formed on the base lens layer  15   a  as shown in  FIG. 6B . The resist layer  74  is formed of positive-type photosensitive resist, an exposed portion of which is removed by development, for example. The resist layer  74  can be formed by the spin coating method or the roll coating method, for example. Then, the resist layer  74  is exposed to light and development is performed via the mask  75  in which light shielding portions  75   a ,  75   b , and  75   c  are provided so as to correspond to the respective positions at which the convex portions  16 , the convex portions  17 , and the convex portion  18  are formed. In the mask  75 , the size of each light shielding portion  75   a  corresponding to each convex portion  16  (diameters in the X direction and the Y direction) is the same as the size of each light shielding portion  75   b  corresponding to each convex portion  17 . 
     As shown by the arrow in  FIG. 6B , the resist layer  74  is exposed to light by irradiating the mask  75  with exposure light from the upper side, and the development is performed (patterning process). In doing so, as shown in  FIG. 6C , a region other than the regions, which overlap the light shielding portions  75   a ,  75   b , and  75   c  of the mask, in the resist layer  74  is exposed to light and is then removed, and the portions that overlap the light shielding portions  75   a ,  75   b , and  75   c  respectively remain in island shapes. That is, the resist layer  74  is patterned, and portions  76  as the first island-shaped sections, portions  77  as the second island-shaped sections, and a portion  78  as the frame-shaped section are formed. 
       FIG. 9A  is a plan view in the state of  FIG. 6C  after the patterning is performed on the resist layer  74 . As shown in  FIG. 9A , the portions  76 , the portions  77 , and the portion  78  are formed on the base lens layer  15   a . The portions  76  are separate from each other in the X direction, the Y direction, and the diagonal line direction, the portions  77  are separate from each other in the X direction, the Y direction, and the diagonal line direction, and the portions  76 , the portions  77 , and the portion  78  are separate from each other in the X direction, the Y direction, and the diagonal line direction. The portions  76 , the portions  77 , and the portion  78  correspond to the convex portions  16 , the convex portions  17 , and the convex portion  18 , which will be formed in the process performed later, respectively. 
     The portions  76  are aligned in a matrix arrangement at the same arrangement pitch as the arrangement pitch (D 1 ) of the convex portions  16  in the X direction and the Y direction. The portions  77  are aligned in a line in the periphery of the portions  76  at the same arrangement pitch as that of the portions  76 . The portion  78  is arranged in a frame shape in the periphery of the portions  77 . 
     The planar shapes of the portions  76  and the portions  77  are substantially rectangular shapes, each of which has four rounded corners. As a method of rounding the four corners of each of the portions  76  and the portions  77 , the four corners may be mounted in the mask when the resist layer  74  is exposed to light, or the four corners may be rounded from a rectangular state in the mask when the resist layer  74  is exposed to light. The planar shape of the portion  78  is a frame shape in which a pair of portions that extend in the X direction and a pair of portions that extend in the Y direction are connected to each other. 
     Incidentally, the light with which the resist layer  74  is irradiated is transmitted to the side of the substrate  11  in the display region E in the process of exposing the resist layer  74  to light. In contrast, the light with which the resist layer  74  is irradiated is blocked by the light shielding portion  31  in the parting region BS shown with hatched lines directed toward the lower right side in  FIG. 9A  since the light shielding portion  31  is arranged between the base lens layer  15   a  and the intermediate layer  14 . However, light reflected by the light shielding portion  31  is returned to the side of the resist layer  74 . Therefore, the amount of exposure light at a portion, which overlaps the light shielding portion  75   b , of the resist layer  74  is larger than the amount of exposure light at a portion which overlaps the light shielding portion  75   a.    
     Therefore, a diameter D 4  of the portions  77 , which overlap the light shielding portion  75   b  and remain, in the X direction and the Y direction is smaller than a diameter D 3  of the portions  76 , which overlap the light shielding portion  75   a  and remain, in the X direction and the Y direction. The diameter D 4  of the portions  77  is smaller than the diameter D 3  of the portions  76  by about 4% to about 6%, for example. Since the amount of exposure light at a portion that overlap the light shielding portion  75   c  also increases, the size of the remaining portion  78  also decreases.  FIG. 9A  shows outlines of the portions  77  and the portion  78  by two-dotted chain lines in a case in which no light is reflected by the light shielding portion  31 , for comparison. 
     Next, the remaining portions  76 ,  77 , and  78  in the resist layer  74  are softened (melted) by heat treatment such as reflow processing as shown in  FIG. 7A . The melted portions  76 ,  77 , and  78  are brought into a fluidized state, and the surfaces thereof are deformed into curved surfaces due to an effect of surface tension. In doing so, convex portions  76   a ,  77   a , and  78   a  with substantially oval spherical shapes are formed from the remaining portions  76 ,  77 , and  78  on the base lens layer  15   a . The convex portions  76   a ,  77   a , and  78   a  have substantially concentric circle shapes in plan view on the side of tip ends of the substantially spherical shapes while the convex portions  76   a ,  77   a , and  78   a  have substantially rectangular shapes with four rounded corners in plan view on the side of the bottoms thereof (the side of the base lens layer  15   a ). 
     In the process shown in  FIG. 6B , the convex portions  76   a ,  77   a , and  78   a  as shown in  FIG. 7A  may be processed from the resist layer  74  by performing an exposure method using a gray scale mask or an area gradation mask or a multi-stage exposure method, for example, on the resist layer  74 . 
     Next, anisotropic etching such as dry etching is performed on the convex portions  76   a ,  77   a , and  78   a  and the base lens layer  15   a  from the upper side as shown in  FIG. 7B  (etching process). By the etching process, the convex portions  76   a ,  77   a , and  78   a  formed of resist are gradually removed, and exposed portions of the base lens layer  15   a  are etched and removed as the convex portions  76   a ,  77   a , and  78   a  are removed. 
     After the convex portions  76   a ,  77   a , and  78   a  are entirely removed, the respective shapes of the convex portions  76   a ,  77   a , and  78   a  are transferred to the base lens layer  15   a , and the convex portions  16   a ,  17   a , and  18   a  are formed. In this process, the respective shapes of the formed convex portions  16   a ,  17   a , and  18   a  can be substantially the same as the respective shapes of the convex portions  76   a ,  77   a , and  78   a  under such a condition that enables the etching rate of the material (resist) of the convex portions  76   a ,  77   a , and  78   a  to be substantially the same as the etching rate of the material of the base lens layer  15   a  in the anisotropic etching. 
     In the etching process, the convex portions  16   a  for configuring the second microlenses ML 2  are formed by etching the base lens layer  15   a  along the convex portions  76   a  that are shaped into convex portions by patterning the resist layer  74 . Therefore, each of the plurality of convex portions  16   a  formed in the display region E is formed under influences of the convex portions  16   a  in the periphery thereof. 
     In a case in which only the convex portions  16   a  are formed and the convex portions  17   a  are not formed in the periphery thereof, the convex portions  16   a  that are formed in the outermost periphery in the display region E in the etching process do not have adjacent convex portions  16   a  on one side (outer side). Therefore, the amount of removal of the base lens layer  15   a  in the etching process increases for the convex portions  16   a  formed in the outermost periphery than for the convex portions  16   a  around which adjacent convex portions  16   a  are present, and differences in shapes occurs. As a result, variations in the properties occur between the second microlenses ML 2  in the outermost periphery and the other second microlenses ML 2  positioned inside the second microlenses ML 2  in the outermost periphery. 
     Thus, the occurrence of the differences in shapes of the second microlenses ML 2  (convex portions  16   a ) in the display region E is avoided by arranging the dummy microlenses MLd (convex portions  17   a ) that do not contribute to display in the periphery of the second microlenses ML 2  (convex portions  16   a ) that contribute to display in this embodiment. In addition, the differences in shapes of the second microlenses ML 2  (convex portions  16   a ) in the display region E can be further suppressed by arranging the convex portion  18   a  in the frame shape in the periphery of the dummy microlenses MLd (convex portions  17   a ). 
     In the embodiment, the dummy microlenses MLd (convex portions  17   a ) that are arranged in the periphery of the second microlenses ML 2  (convex portions  16   a ) are aligned only in one line in each of the X direction and the Y direction in order to reduce the number of processes in the flattening processing for flattening the surface of the optical path length adjustment layer  32  that is formed in a process performed later. This will be described later with reference to the processes in the flattening processing shown in  FIG. 8C . 
     Next, the peripheral edge of the convex portion  18   a  in the base lens layer  15   a  is removed by a predetermined thickness from the side of the surface, and the flattened section  19   a  with a substantially flat surface is formed as shown in  FIG. 7C . As a method of forming the flattened section  19   a , a region other than the region, in which the flattened section  19   a  is formed, in the base lens layer  15   a  is covered with a protection member, and anisotropic etching such as dry etching is performed on the base lens layer  15   a.    
       FIG. 9B  is a plan view of the base lens layer  15   a  in a state after the process shown in  FIG. 7C  is performed. The planer shapes of the convex portions  16   a  and the convex portions  17   a  shown in  FIG. 9B  are obtained by transferring the planar shapes of the portions  76  and the portions  77  after the patterning process shown in  FIG. 9A  is performed. The outside of the convex portion  18   a  is etched and removed while the inside portion thereof with a width V in the portions extending in the X direction and the portions extending in the Y direction in the frame shape is made to remain. The width V of the remaining convex portion  18   a  is appropriately set such that the width W of the convex portion  18  that is formed by laminating the superficial lens layer  15   b  on the base lens layer  15   a  in the following process shown in  FIG. 8A  becomes equal to or less than ½ of the arrangement pitch of the convex portions  16 . 
     If the predetermined thickness (depth) by which the base lens layer  15   a  is removed from the side of the surface of the convex portion  18   a  for forming the flattened section  19   a  is assumed to be H 3 , a level difference H 3  is formed between the formed flattened section  19   a  and the uppermost portion of the convex portion  18   a  as shown in  FIG. 7C . The level difference H 3  is appropriately set such that a level difference H 2  between the flattened section  19  that is formed by laminating the superficial lens layer  15   b  on the base lens layer  15   a  in the following process shown in  FIG. 8A  and the uppermost portion of the convex portion  18  is smaller than ½ of the height H 1  of the convex portion  18 . 
     The flattened section  19   a  is formed for the purpose of reducing the number of the flattening processing for flattening the surface of the optical path length adjustment layer  32  that is formed in the process performed later. This will also be described with reference to the processes in the flattening processing shown in  FIG. 8C . 
     Next, the superficial lens layer  15   b  is laminated and formed on the base lens layer  15   a  as shown in  FIG. 8A . The superficial lens layer  15   b  is formed of the same material as that of the base lens layer  15   a  by the same method as that of the base lens layer  15   a . The laminated base lens layer  15   a  and the superficial lens layer  15   b  configure the second lens layer  15 . As described above, refraction and reflection of light at the boundary between the base lens layer  15   a  and the superficial lens layer  15   b  can be substantially ignored. 
     The convex portions  16 ,  17 , and  18  are formed in enlarged states of the convex portions  16   a ,  17   a , and  18   a  on the surface of the second lens layer  15  (superficial lens layer  15   b ) by laminating the superficial lens layer  15   b  so as to cover the convex portions  16   a ,  17   a , and  18   a  in the base lens layer  15   a . As a result, the convex portions  16  that are adjacent in the X direction and the Y direction are connected to each other. 
     Another configuration is also applicable in which the base lens layer  15   a  and the superficial lens layer  15   b  are formed of materials with different optical refraction indexes. In the case of employing such a configuration, light is refracted between the base lens layer  15   a  and the superficial lens layer  15   b . It is also possible to enhance the efficiency of utilizing the light by collecting or diffusing incident light by utilizing the refraction of the light. 
     Next, the first optical path length adjustment layer  32   a  is formed by depositing a light transmitting inorganic material with an optical refraction index difference from that of the second lens layer  15  so as to cover the second lens layer  15  as shown in  FIG. 8B . The first optical path length adjustment layer  32   a  can be formed by using the CVD method, for example. The first optical path length adjustment layer  32   a  has a surface with an uneven shape that reflects unevenness caused by the convex portions  16 ,  17 , and  18  of the second lens layer  15 . 
     In this process, the first optical path length adjustment layer  32   a  is laminated, and the slit  33  is formed inside the first optical path length adjustment layer  32   a . The first optical path length adjustment layer  32   a  grows so as to enlarge the shapes of the convex portions  16  of the second lens layer  15 . Since the growth substantially uniformly proceeds from the convex portions  16  on both sides at a valley between the convex portions  16 , directions of the growth on the both sides cross at a narrowed portion. The slit  33  as a boundary of the directions of the growth is formed at the crossing portion. The slit  33  grows in a laminated direction (Z direction) inside the first optical path length adjustment layer  32   a.    
     Next, the flattening processing is performed on the first optical path length adjustment layer  32   a  as shown in  FIG. 8C  (processes in the flattening processing). In the processes of the flattening processing, an upper surface is flattened by polishing and removing a portion, in which unevenness is formed, on the upper side than the two-dotted chain line of the first optical path length adjustment layer  32   a  shown in  FIG. 8B  by using the CMP processing, for example. In the processes of the flattening processing, it is necessary to alleviate the level differences in the individual uneven shapes caused by the convex portions  16 ,  17 , and  18  and to alleviate the level differences in a large range corresponding to the entire region including the display region E and the parting region BS. 
     Here, since the diameter D 2  of the convex portions  17  is smaller than the diameter D 1  of the convex portions  16  (see  FIG. 8A ), the density of the material of the first optical path length adjustment layer  32   a  per unit volume in the processes of the flattening processing differs between the display region E in which the convex portions  16  are arranged and the parting region BS in which the convex portions  17  are arrange. In addition, since the convex portions  17  have different shapes from that of the convex portion  18  that is arranged in the periphery thereof, a difference in the density of the material of the first optical path length adjustment layer  32   a  per unit volume in the parting region BS occurs. 
     In the case in which the convex portions  17  are arranged in a plurality of lines in the periphery of the convex portions  16  as disclosed in JP-A-11-202314, for example, the difference in the density of the material of the first optical path length adjustment layer  32   a  per unit volume further increases between the display region E in which the convex portions  16  are arranged and the region in which the convex portions  17  are arranged in the parting region BS. 
     For this reason, the density of the material of the first optical path length adjustment layer  32   a  per unit volume in the processes of the flattening processing differs in three levels in the display region E in which the convex portions  16  are arranged, in the region in which the convex portions  17  are arranged in the parting region BS, and the region in which the convex portion  18  is formed in the periphery of the convex portions  17  in the parting region BS. Therefore, the polishing amount of the first optical path length adjustment layer  32   a  increase and the number of processes in the flattening processing increases in order to alleviate the individual uneven shapes due to the convex portions  16 ,  17 , and  18  and to alleviate the level differences in the large range of the entire region including the display region E and the parting region BS. 
     Since the convex portions  17  are arranged in a line in the periphery of the convex portions  16  in the embodiment, it is possible to reduce the difference in the density of the material of the first optical path length adjustment layer  32   a  per unit volume between the display region E in which the convex portions  16  are arranged and the region in which the convex portions  17  are arranged in the parting region BS as compared with the case in which the convex portions  17  are arranged in the plurality of lines. In doing so, it is possible to reduce the influence of the difference in the density in the region in which the convex portions  17  are arranged with respect to the difference in the density in the large range of the entire region including the display region E and the parting region BS. 
     In a case in which no convex portion  18  is provided in the periphery of the convex portions  17 , a large level difference between the display region E and the parting region BS occurs on the surface of the first optical path length adjustment layer  32   a  that is formed on the second lens layer  15 . Therefore, the number of processes in the flattening processing increases. Since the convex portion  18  is provided in the periphery of the convex portions  17  in the embodiment, it is possible to reduce the level difference between the display region E and the parting region BS on the surface of the first optical path length adjustment layer  32   a  as compared with the case in which no convex portion  18  is provided. 
     Furthermore, the convex portion  18  has the frame shape with the width W by forming the flattened section  19  in the peripheral edge of the convex portion  18 . The continuing convex portion  18  is arranged so as to face the convex portions  17  aligned in a line at positions of the respective sides of the frame shape in the X direction and the Y direction. Therefore, it is possible to reduce the difference in the density of the material of the optical path length adjustment layer  32  per unit volume between the region in which the convex portions  17  are arranged and the region in which the convex portion  18  is arranged at the positions of the respective sides of the frame shape. That is, it is possible to reduce the difference in the density of the material of the optical path length adjustment layer  32  per unit volume in the entire parting region BS. 
     In doing so, it is possible to reduce the difference in the density of the material of the first optical path length adjustment layer  32   a  per unit volume between the display region E and the parting region BS as compared with the case in which no flattened section  19  is formed. In addition, the level difference H 2  between the uppermost portion of the convex portion  18  and the flattened section  19  and the width W of the convex portion  18  are set so as to minimize the difference in the density of the material of the first optical path length adjustment layer  32   a  per unit volume between the display region E and the parting region BS. 
     As a result, it is possible to reduce the polishing amount of the first optical path length adjustment layer  32   a  in the processes of the flattening processing and to thereby reduce the number of processes according to the embodiment. In addition, it is possible to enhance flatness of the surface of the first optical path length adjustment layer  32   a.    
     Next, the second optical path length adjustment layer  32   b  is laminated and formed on the first optical path length adjustment layer  32   a  as shown in  FIG. 4A . The second optical path length adjustment layer  32   b  is formed by using the same material as that of the first optical path length adjustment layer  32   a  by the same method as that of the first optical path length adjustment layer  32   a . In addition, the flattening processing is performed on the surface of the second optical path length adjustment layer  32   b  to further enhance the flatness of the surface. Since the second optical path length adjustment layer  32   b  is formed on the first optical path length adjustment layer  32   a  after the flattening processing, the slit  33  is not formed in an extended manner. 
     The laminated first optical path length adjustment layer  32   a  and the second optical path length adjustment layer  32   b  configure the optical path length adjustment layer  32 . The second microlenses ML 2  are configured by covering the convex portions  16  with the optical path length adjustment layer  32 . In addition, the dummy microlenses MLd are configured by covering the convex portions  17  with the optical path length adjustment layer  32 . 
     The microlens array substrate  10  is completed as described above. After the completion of the microlens array substrate  10 , the facing substrate  30  is obtained by sequentially forming the common electrode  34  and the orientation film  35  on the microlens array substrate  10  by using a known technology as shown in  FIG. 3 . Then, the element substrate  20  is obtained by sequentially forming the light shielding portion  22 , the insulating layer  23 , the TFTs  24 , the insulating layer  25 , the light shielding portion  26 , the insulating layer  27 , the pixel electrodes  28 , and the orientation film  29  on the substrate  21  by using a known method. 
     Subsequently, the element substrate  20  and the facing substrate  30  are positioned, a thermosetting or photo-curable adhesive is arranged as the sealing material  42  (see  FIG. 1 ) between the element substrate  20  and the facing substrate  30  and is then cured to attach the substrates. Then, the liquid crystal device  1  is completed by sealing and interposing liquid crystal in spaces configured by the element substrate  20 , the facing substrate  30 , and the sealing material  42 . The liquid crystal may be arranged in the region surrounded by the sealing material  42  before the element substrate  20  and the facing substrate  30  are attached to each other. 
     The liquid crystal device  1  according to the embodiment includes, on the facing substrate  30 , the microlens array substrate  10  that includes two-stage microlens array, each of which is formed of the first microlens ML 1  and the second microlens ML 2 , and has a surface with satisfactory flatness. Therefore, it is possible to enhance the efficiency of utilizing light, to further uniformize the gap between the element substrate  20  and the facing substrate  30 , and to thereby provide the liquid crystal device  1  with bright display and excellent display quality. 
     Electronic Apparatus 
     Next, a description will be given of an electronic apparatus according to the embodiment with reference to  FIG. 10 .  FIG. 10  is a diagram schematically showing a configuration of a projector as the electronic apparatus according to the embodiment. 
     As shown in  FIG. 10 , a projector (projection-type display apparatus)  100  as the electronic apparatus according to the embodiment includes a polarized illumination device  110 , two dichroic mirrors  104  and  105 , three reflective mirrors  106 ,  107 , and  108 , five relay lenses  111 ,  112 ,  113 ,  114 , and  115 , three liquid crystal light valves  121 ,  122 , and  123 , a cross dichroic prism  116 , and a projection lens  117 . 
     The polarized illumination device  110  includes a lamp unit  101  as a light source formed of a white light source such as an ultrahigh pressure mercury lamp or a halogen lamp, an integrator lens  102 , and a polarization conversion element  103 . The lamp unit  101 , the integrator lens  102 , and the polarization conversion element  103  are arranged along an optical axis Lx of the system. 
     The dichroic mirror  104  reflects red light (R) and transmits green light (G) and blue light (B) therethrough from among polarized light fluxes output from the polarized illumination device  110 . The other dichroic mirror  105  reflects the green light (G) that has been transmitted through the dichroic mirror  104  and transmits the blue light (B). 
     The red light (R) reflected by the dichroic mirror  104  is reflected by the reflective mirror  106  and is then incident on the liquid crystal light valve  121  via the relay lens  115 . The green light (G) reflected by the dichroic mirror  105  is incident on the liquid crystal light valve  122  via the relay lens  114 . The blue light (B) transmitted through the dichroic mirror  105  is incident on the liquid crystal light valve  123  via a light guiding system formed of the three relay lenses  111 ,  112 , and  113  and the two reflective mirrors  107  and  108 . 
     The light transmitting liquid crystal light valves  121 ,  122 , and  123  as the light modulation elements are respectively arranged so as to face the incident surfaces of the cross dichroic prism  116  for light with the respective colors. The light that is incident on the liquid crystal light valves  121 ,  122 , and  123  is modulated based on video information (video signal) and is output toward the cross dichroic prism  116 . 
     The cross dichroic prism  116  is formed such that four right angle prisms are attached and a dielectric body multilayered film that reflects the red light and a dielectric body multilayered film that reflects the blue light are formed into a cross shape in the inner surface thereof. The light with the three colors is synthesized by these dielectric body multilayered films, and light representing a color image is synthesized. The synthesized light is projected to a screen  130  by the projection lens  117  as a projection optical system, and an image is displayed in an enlarged manner. 
     The liquid crystal light valve  121  is arranged between a pair of polarization elements, which are arranged in crossed nicols on the incident side and the output side of the color light, at an interval. The other liquid crystal light valves  122  and  123  are configured in the same manner. The liquid crystal device  1  according to the embodiment is applied to the liquid crystal light valves  121 ,  122 , and  123 . 
     According to the microlens array substrate  10 , the liquid crystal device  1 , the projector  100 , and the method of manufacturing the microlens array substrate of the embodiment as described above, it is possible to achieve the following effects. 
     (1) Since the dummy microlenses MLd (convex portions  17 ) are arranged in a line in the periphery of the second microlenses ML 2  (convex portions  16 ), it is possible to reduce the difference in the density of the material of the optical path length adjustment layer  32  per unit volume between the display region E in which the second microlenses ML 2  are arranged and the parting region BS in which the dummy microlenses MLd are arranged as compared with the case in which the dummy microlenses MLd are arranged in a plurality of lines. In doing so, it is possible to enhance the flatness of the surface of the microlens array substrate  10  (optical path length adjustment layer  32 ). In addition, it is possible to reduce the number of processes in the flattening processing of the optical path length adjustment layer  32  in manufacturing the microlens array substrate  10  and to thereby enhance productivity of the microlens array substrate  10 . 
     (2) Since the convex portion  18  is arranged in the periphery of the convex portions  17  of the second lens layer  15 , it is possible to reduce the difference in the density of the material of the optical path length adjustment layer  32  per unit volume between the region in which the convex portions  17  are arranged in the parting region BS and the peripheral region in which the convex portion  18  is arranged. In doing so, it is possible to further enhance the flatness of the surface of the microlens array substrate  10  (optical path length adjustment layer  32 ). In addition, it is possible to further reduce the number of processes in the flattening processing of the optical path length adjustment layer  32  in manufacturing the microlens array substrate  10 . 
     (3) Since the convex portion  18  is arranged in the frame shape in the periphery of the convex portions  17  that are arranged in a line, the convex portion  18  is arranged so as to face the convex portions  17  that are aligned in a line at the positions of the respective sides of the frame shape in the X direction and the Y direction. Therefore, it is possible to reduce the difference in the density of the material of the optical path length adjustment layer  32  per unit volume between the region in which the convex portions  17  are arranged and the region in which the convex portion  18  is arranged at the positions of the respective sides of the frame shape. 
     (4) The convex portions  17  are arranged at substantially the same arrangement pitch D 1  in the X direction and the Y direction, and the width W of the convex portion  18 , which is arranged in the frame shape in the periphery thereof, in the X direction and the Y direction is equal to or less than ½ of the arrangement pitch D 1  of the convex portions  17 . Therefore, since the continuing convex portion  18  with the width W that is equal to or less than ½ of the arrangement pitch D 1  is arranged so as to face the convex portions  17  that are aligned in a line at substantially the same arrangement pitch D 1  at the positions of the respective sides of the frame shape of the convex portion  18  in the X direction and the Y direction, it is possible to further reduce the difference in the density of the material of the optical path length adjustment layer  32  per unit volume between the region in which the convex portions  17  are arranged and the region in which the convex portion  18  is arranged in the parting region BS. 
     (5) Since the dummy microlenses MLd that are configured by covering the convex portions  17 , which overlap the light shielding portion  31  in a plane, with the optical path length adjustment layer  32  are arranged so as to overlap the light shielding portion  31  in a plane, light that is incident on the microlens array substrate  10  is not transmitted through the dummy microlenses MLd. Therefore, differences in the properties of the dummy microlenses MLd from those of the second microlenses ML 2  that are arranged in the display region E do not affect the light that is transmitted through the microlens array substrate  10  due to the diameter D 2  of the convex portions  17  that is smaller than the diameter D 1  of the convex portions  16 . 
     (6) The liquid crystal device  1  includes the element substrate  20  that is provided with the TFTs  24 , the facing substrate  30  that is arranged so as to face the element substrate  20 , and the liquid crystal layer  40  that is arranged between the element substrate  20  and the facing substrate  30 . Since the facing substrate  30  includes the microlens array substrate  10 , the flatness of the surface of the facing substrate  30  is enhanced, and also, the second microlenses ML 2  with a uniform property, which are formed of the convex portions  16  of the second lens layer  15 , are arranged so as to overlap the opening regions T of the pixels P in a plane. In doing so, it is possible to provide the liquid crystal device  1  that displays a bright image with excellent quality. 
     (7) Since the projector  100  includes the liquid crystal device  1  that is capable of providing bright display and excellent display quality even if a plurality of pixels P are finely arranged, it is possible to provide the projector  100  with bright display and excellent display quality. 
     (8) Since the convex portions  17  are arranged in a line in the periphery of the convex portions  16  of the second lens layer  15  according to the method of manufacturing the microlens array substrate, it is possible to reduce the difference in the density of the material of the optical path length adjustment layer  32  per unit volume between the display region E in which the convex portions  16  are arranged and the parting region BS in which the convex portions  17  are arranged as compared with the case in which the convex portions  17  are arranged in a plurality of lines. Since the peripheral edge of the convex portion  18  is removed from the side of the surface of the second lens layer  15  by the predetermined thickness H 2 , it is possible to reduce the difference in the density of the material of the optical path length adjustment layer  32  per unit volume in the region in which the convex portions  17  are arranged and the region in which the convex portion  18  is arranged. In doing so, it is possible to reduce the number of processes in the flattening processing since the polishing amount is reduced. Therefore, it is possible to enhance productivity of the microlens array substrate  10 . In addition, it is possible to enhance flatness of the surface of the microlens array substrate  10  (optical path length adjustment layer  32 ). 
     The aforementioned embodiment is only an aspect of the invention, and modifications and applications can optionally be made within the scope of the invention. As a modification example, the following example can be considered. 
     MODIFICATION EXAMPLE 
     The electronic apparatus to which the liquid crystal device  1  according to the embodiment is not limited to the projector  100 . The liquid crystal device  1  can be suitably used a display section in an information terminal apparatus such as a projection-type head-up display (HUD), a direct view-type head mount display (HMD), an electronic book, a personal computer, a digital still camera, a liquid crystal television, a view finder-type video camera, a car navigation system, an electronic personal organizer, or a POS. 
     This application claims priority to Japan Patent Application No. 2015-30391 filed Feb. 19, 2015, the entire disclosures of which are hereby incorporated by reference in their entireties.