JP2002122708A - Microlens substrate having alignment marker and liquid crystal display device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microlens substrate having an alignment marker attached thereto, having a function of a lens to eliminate relative displacement between a microlens and the alignment marker, and to realize positioning with respect to another element in a short period of time and a liquid crystal display device using the same. SOLUTION: The microlens substrate 5 is provided with the alignment marker 2, which serves as a reference for superposition on an alignment marker 3 of another element. A group of the microlenses 4 and the alignment marker 2 are formed by filling a transparent material with a high refractive index into a recessed parts, forming part of the transparent material. Both of them have nearly equal depths and curvatures of recessed parts of the recessed parts forming parts. The liquid crystal display device 1, including the microlens substrate 5, shows no uneven brightness and has improved condensing efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microlens substrate having an alignment marker having a lens function and a liquid crystal display device using the same, and particularly to a highly accurate alignment between a driving substrate and a microlens substrate. The present invention relates to a liquid crystal display device which realizes the above, has no luminance unevenness, and has improved light collection efficiency.

[0002]

2. Description of the Related Art Along with colorization and high definition of a liquid crystal display device, the area ratio of a portion through which light such as wirings and elements does not transmit increases, so that incident light is not effectively used and a screen becomes dark. is there. In order to solve this problem, improvements for higher luminance are currently in progress. In general, a liquid crystal display device includes a driving substrate on which a thin film transistor (TFT) and the like are formed, and a substrate on which a color filter and a light shielding layer are formed (see FIG. 1).

In recent years, as an alternative to a method of increasing the power consumption of an illumination light source and increasing the brightness of a screen, a microlens for a pixel is provided in an opening of each pixel, and incident light is condensed on the pixel to make it seem apparent. A method of improving the light collection rate and brightening the screen display has been used.

[0004]

In a method of manufacturing a liquid crystal display device, an alignment marker is formed at the same time when a color filter, a light shielding layer, and the like are formed on a substrate, and the alignment with the driving substrate is performed using the alignment marker. Has been taken. Therefore, when the microlenses are provided on the substrate side, there is a problem that a positional shift occurs between the microlenses and the pixel portion, and the light collection rate decreases.

[0005] In addition, in the configuration in which the microlens array substrate is adhered to the microlens array substrate, a new alignment marker for position alignment between the color filter and the like of the substrate and the microlens array is required. Is also reduced.

Under such circumstances, along with the development of a microlens having a high light-collecting efficiency, a method of manufacturing a liquid crystal display device which realizes a highly accurate alignment of the microlens and the pixel has been proposed (Japanese Patent Laid-Open No. 09-2009). 189901). In this method, the pattern for the lens and the pattern for the alignment marker are formed in the same process when forming the resist pattern, and the microlens and the alignment marker are formed using a method such as isotropic etching, ion replacement, or machining, No relative displacement between the lens pattern and the alignment marker occurs.

[0007] However, in terms of manufacturing speed due to mass production, it takes time to align an alignment marker at the time of joining a drive substrate and a microlens array substrate, which may hinder tact-up. Therefore, there is a need for a liquid crystal display device and a method of manufacturing the liquid crystal display device, which can achieve high-accuracy alignment and bonding between the drive substrate and the microlens array substrate in a short time.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to (1) eliminate a relative displacement between a microlens and an alignment marker in a microlens substrate; 2) High-precision bonding between the driving substrate and the microlens substrate can be realized in a short time, and (3) prevention of a decrease in the pixel aperture ratio and the light-collecting ratio due to poor precision in the bonding between the driving substrate and the microlens substrate. (4) To provide a microlens substrate with an alignment marker having a lens function, which can improve the light collection efficiency without luminance unevenness, and a liquid crystal display device using the same.

[0009]

A microlens substrate according to the present invention for achieving the above object is a microlens substrate provided with an alignment marker serving as a reference for superposition with an alignment marker of another element. ,
The microlens group and the alignment marker of the microlens substrate are formed by filling a transparent material concave portion with a transparent material having a higher refractive index than the transparent material concave portion. Is characterized in that the depth is substantially equal to the curvature. With this configuration, there is no displacement between the microlens group and the alignment marker, and the alignment with another element can be performed in a short time by the alignment marker having a lens function.

Based on the above basic configuration, the following modes are possible. The alignment marker includes a lens form composed of a single microlens, a lens form composed of an aggregate of microlenses, a lens form composed of an aggregate in which microlenses are arranged in a cross shape, and an aggregate in which microlenses are arranged in one row. Lens form, micro lens
It has a lens form and the like consisting of an aggregate arranged in two rows.
This form may be appropriately determined according to the application.

Further, a liquid crystal display device according to the present invention, which achieves the above object, comprises a driving substrate including a pixel portion composed of a plurality of pixels and an alignment marker provided as a reference for superposition; A microlens substrate provided with an alignment marker serving as a reference for superposition of a correspondingly provided microlens group and an alignment marker of the drive substrate, wherein the microlens substrate is arranged with respect to the drive substrate. And facing each other at a predetermined interval.

The basic components and more specific embodiments of the present invention have been described above, and the details and operation thereof will be described below by way of typical examples.

First, an example of a method for manufacturing a microlens substrate without a relative displacement between the microlens and the alignment marker in the microlens substrate will be described. The microlens of the present invention can be formed from a microlens mold or a mold master. First, a first mask layer is formed over a conductive substrate or a substrate having an electrode layer. As a material for the plating substrate, any material of a metal, a semiconductor, and an insulator may be used, and a metal plate, a glass substrate, a silicon wafer, or the like having good flatness can be used.
If a metal material is used as the plating substrate, there is no need to form an electrode layer. In the case where a semiconductor is used, it is not always necessary to form an electrode layer as long as it has an electric conductivity that enables electroplating. The electrode layer is selected from materials that are not corroded by the plating solution used because they are exposed to the plating solution. The first mask layer may be any material having an insulating property, and either an inorganic insulator or an organic insulator can be used. As a method for forming the electrode layer and the first mask layer, a thin film forming method such as a vacuum evaporation method, a spin coating method, a dipping method, and a chemical deposition method (CVD) is used.

Next, a plurality of microlens openings corresponding to the microlens pitch are formed in the first mask layer in a region wider than a desired microlens group region. The shape of the opening is preferably circular or slit-like. The opening is formed by etching using a semiconductor photolithography process capable of forming a minute opening and etching. When a photoresist is used as the first mask layer, an etching step can be omitted.

The electroplating is performed by the following method. The above-mentioned plating substrate is used as a work, immersed in a plating solution containing metal ions, an external power supply is connected between the substrate and the anode plate, and a current is applied to form a first plating layer in the opening. Plating is formed in the opening, and by continuing plating, the first plating layer also spreads on the first mask layer to form a structure such as a hemisphere. The microstructure of the microlens mold or mold master to be manufactured is in the range of several μm to several hundred μm, and therefore, the size of the opening is the desired microstructure of the microlens mold or mold master. Must be smaller than body diameter. In order for plating to grow isotropically, the size of the opening is preferably smaller than the diameter of the hemispherical structure. As the size decreases, the shape of the hemispherical structure approaches a true sphere, the radius of curvature can be reduced, and the top of the plating layer also has a spherical shape.

A structure such as a hemisphere is formed by metal ions in a plating bath being precipitated by an electrochemical reaction. In electroplating, the thickness of the first plating layer can be easily controlled by controlling the plating time and the plating temperature. The main plating metals are Ni, Au, Pt, C
r, Cu, Ag, Zn and the like.
n, Sn—Co, Ni—Fe, Zn—Ni, and the like. Any other material that can be electroplated can be used, but a material that does not form the electrode layer and the alloy layer is preferable.

In the first plating layer formed here, the peripheral portion of the array tends to grow larger than the central portion. This is because the current distribution is not uniform and the current concentrates at the ends of the electrodes.

Here, by forming the microlens opening group region wider than a desired microlens group region (used region), the first group which grows larger than the central portion is formed.
Is outside the desired microlens group region.

Subsequently, the first plating layer which has grown larger than the central portion of the peripheral portion of the array is selectively removed by etching by the method described below, so that the first plating layer having a substantially uniform height and the same curvature is obtained. An array of one plating layer can be obtained. At the same time, a first plating layer group serving as an alignment marker can be formed.

In the method, first, the first mask layer is removed. Next, a second mask layer is formed on the desired microlens group region including the first plating layer grown to a substantially uniform size and the first plating layer region of the alignment marker region outside the microlens group region. Form. As the second mask layer, any of an inorganic material and an organic material can be used, but a material having resistance to an etching solution in a later step is used. As a method for forming the second mask layer, a thin film formation method such as a vacuum evaporation method, a spin coating method, and a dipping method is used. In forming the second mask layer only in a selective region, the second mask layer is formed by a semiconductor photolithography process and etching. When a photoresist is used as the second mask layer, an etching step can be omitted.

Before the formation of the second mask layer, the first mask
Although it is not necessary to remove the mask layer,
The adhesion of the mask layer is improved. Especially the first mask layer,
When both of the second mask layers are photoresists, the effect is great.

Next, the first plating layer exposed from the second mask layer is removed by etching. As an etching method, dry etching or wet etching is used.
An etching gas and an etching solution that selectively etch the first plating layer exposed from the second mask layer without etching the second mask layer, the electrode layer, and the substrate are used.

The remaining first plating layer in the microlens area covered by the second mask layer has a substantially uniform size and is a hemispherical structure array having a small in-plane distribution of diameters. Also, the first plating layer as an alignment marker can be left by covering it with the second mask layer.

A plurality of microlens openings corresponding to a desired microlens pitch and an opening in which a first plating layer left unetched as an alignment marker grows from the electrode layer are formed by the same process. Therefore, there is no relative displacement between the microlens region and the alignment marker in the microlens substrate. Furthermore, the height and the curvature of the first plating layer remaining as the alignment marker in the microlens region become substantially equal (that is, the alignment marker region is selected so as to be so).

Next, the second mask layer is removed, and a second plating layer is formed from the first plating layer to the electrode layer. The method of forming the second plating layer may be any of electroplating, electroless plating, and electrodeposition. However, by using electroless plating, a mold for a microlens or a mold master having high gloss can be obtained. Furthermore, since this is an isotropic plating growth, the radius of curvature in the diagonal direction and the horizontal direction of each plating layer in the microlens area can be equalized, and the height of the plating layer in the microlens area and the alignment marker can be adjusted. The heights of the plating layers can be made substantially equal. By the second plating layer, the first plating layer is firmly fixed on the electrode layer, and it is possible to prevent the first plating layer from dropping off in the subsequent process, so that the durability of the microlens mold or the mold master can be improved. Becomes better. The height of the plating layer in the microlens region obtained by these methods is substantially equal to the height of the plating layer of the alignment marker structure.

The microlens mold is obtained by forming a mold material on the microlens mold master (original plate) and then peeling the mold. Since the microlens mold can be formed directly from the original plate formed by electroplating, it can be manufactured at low cost without requiring expensive equipment. As the method of peeling, the original plate and the substrate may be mechanically peeled, and these can be used plural times. Further, after a material to be a microlens is formed on the microlens mold, the microlens can be formed by peeling the material. This makes it possible to easily manufacture microlenses having the same shape at low cost. As a material of the micro lens,
A material that is easily peelable from the microlens mold is used. When using resin as the microlens material,
There are light-transmissive thermosetting resins, ultraviolet-curing resins, electron beam-curing resins, and the like. Alternatively, if you use molten glass,
Glass microlenses can be made. In forming the flat microlens, the depressions between the convex portions may be filled with a material having a lower refractive index than the material used for the convex portions so that the obtained lens convex portions become flat.

Further, since the top of the first plating layer is obtained in a spherical shape, the vertex of the microlens to be formed also has a spherical shape, and the microlens is formed by etching from the resist pattern hole. Method (Japanese
No. 8,136,704) does not cause the problem that the lens apex is flattened and cannot be focused smaller than the resist pattern hole diameter.

Next, the microlens substrate thus obtained and the drive substrate are bonded. The bonding may be performed using an aligner. The drive substrate and the microlens substrate are relatively moved with respect to the drive substrate-side alignment marker and the microlens substrate-side alignment marker, and the two substrates are superposed. Here, since the alignment marker of the microlens substrate has a lens form, when the drive substrate and the microlens substrate are brought closer to each other during bonding, an optical image of the alignment marker on the drive substrate side is enlarged. As a result, the alignment marker on the drive substrate side can be instantaneously recognized. As a result, highly accurate bonding of the driving substrate and the microlens substrate can be realized in a short time.

Furthermore, the height of the lens vertex of the microlens and the height of the vertex of the alignment marker are substantially equal (in the same plane).
Since both the lens vertex of the microlens and the vertex of the alignment marker are within the focal depth of the aligner-side lens system, highly accurate alignment can be realized. Furthermore, since the size of each lens in the micro lens area is equal, it is possible to prevent image quality deterioration such as uneven brightness. In this way, it is possible to prevent a decrease in the pixel aperture ratio and the light-collection rate due to a poor precision in bonding the drive substrate and the microlens substrate, and to improve the light-collection efficiency.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to examples.

(First Embodiment) FIG. 1A shows an embodiment of a liquid crystal display device according to the present invention, in which a microlens substrate 5 is provided.
FIG. 4B is a side view showing a state in which the driving substrate 6 is superposed on the microlens substrate 5, and FIG. 4C is a top view showing the driving substrate 6. FIG. 2 is a side view showing a mold or a mold master for producing a microlens according to the present invention. In this embodiment, FIG.
(C) A liquid crystal display device 1 including a driving substrate 6 having a cross-shaped alignment marker 3 and a microlens substrate 5 having an alignment marker 2 for realizing highly accurate alignment with the driving substrate. explain.

First, an example of a method for manufacturing a microlens mold or a mold master will be described with reference to FIG. A 4-inch φ silicon wafer having a silicon dioxide film having a thickness of 1 μm formed on both surfaces by thermal oxidation using an oxidizing gas is used as the substrate 8 shown in FIG. Ti and Pt were each deposited on the wafer by 50 ° by vacuum sputtering, which is one of the thin film forming methods.
An electrode layer 9 is formed by continuously forming a film at 500 °. A positive photoresist (Az1500: manufactured by Client) is applied thereon to form a first mask layer 10. Next, the photoresist is exposed and developed by photolithography,
The circular opening 11 is formed by exposing the electrode layer 9. The openings 11 are provided in an array in a region of 95 mmφ on the surface of the silicon wafer. Its diameter is 5 μm, and the distance between adjacent openings 11 is 18 μm (FIG. 3A).

Using this substrate as a work, the electrode layer 10
Using a nickel plating bath composed of nickel sulfate, nickel chloride, boric acid and a brightener, with the
Ni plating is performed at 50 ° C. and a cathode current density of 40 A / dm ² . The first plating layer 12 made of Ni is
And the first plating layer 12 spreads on the first mask layer 10. The radius of the center of the array is about 10μm
The first plating layer 12 is grown until a hemispherical structure is obtained (FIG. 3B). When the radius of the first plating layer 12 was about 10 μm at the center of the array, the first plating layer 12 having a maximum radius of about 15 μm was formed at the periphery of the array.

Next, the first mask layer 10 is removed with acetone and N, N-dimethylformamide. Then, a positive photoresist (AzP4620: manufactured by Client)
Is coated, exposed and developed to remove 1064 around the array
A second mask layer 13 as shown in FIG. 4 is provided on the first plating layer 12 grown at a position corresponding to the x808 regions and the alignment marker. This exposes the first plating layer 12 at the periphery of the array (FIG. 3C).

The first plating layer 12 made of nickel exposed from the second mask layer 13 is removed by etching using an etching solution (FIG. 3D). As a result, the first plating layer 12 made of nickel exposed from the second mask layer
Can be completely removed. Next, by removing the second mask layer 13 with acetone and N, N-dimethylformamide, 1
An array of 064 × 808 first plating layers 12 and alignment markers 15 can be formed (FIG. 3).
(E)). At this time, the in-plane distribution of the radius of the first plating layer 12 was within 5%.

Next, Ni electroless plating was performed at a bath temperature of 90 ° C. using an electroless Ni plating solution (Alnic PX, manufactured by Pax) containing a reducing agent for hypophosphite to form a second plating layer 14. Is formed (FIG. 3F). Thereby, the first
The plating layer 12 was firmly fixed on the electrode layer 9, and a high gloss glossy mold or mold master was obtained by using electroless plating for forming the second plating layer.
The radius of curvature of each plating layer in the diagonal direction and the horizontal direction is almost equal, the average radius of curvature is 20 μm, and the distribution of the radius of curvature falls within ± 1 μm to form a mold master having a uniform shape. did it. Further, the in-plane distribution of the heights of the plating layer in the microlens group and the plating layer serving as the alignment marker structure 15 was within 5%.

Next, a release agent for electroforming is applied. Using this substrate as a cathode, a Ni plating bath composed of nickel sulfamate, nickel bromide, boric acid and a brightener was used.
Ni electroplating is performed at 0 ° C. and a cathode current density of 5 A / dm ² to form a mold. Thereafter, the mold is released from the substrate to form a microlens mold.

Next, an example of a method for manufacturing the microlens substrate 5 will be described. After applying the ultraviolet curable resin to the microlens mold, a glass substrate serving as a support substrate is mounted thereon. After being cured by irradiation with ultraviolet rays, the resultant is peeled off to produce the convex microlens 4. Further, an ultraviolet curable resin having a smaller refractive index than that of the ultraviolet curable resin is filled in the grooves between the convex portions to produce the flat microlens substrate 5. The flat microlens substrate 5 obtained here is used as the microlens group and the alignment marker 2 in the non-display area.
The depth and the curvature of the concave portion are substantially equal, and the transparent material concave portion (the upper portion of the flat microlens substrate 5 in FIG. 1A) has a higher refractive index than the transparent material (the flat microlens substrate in FIG. 1A). 5 (the lower part).

Subsequently, the alignment marker 2 on the microlens side is aligned with the alignment marker 3 on the driving substrate using an aligner, and the attachment is performed by moving the driving substrate 6 and the microlens substrate 5 relatively. At this time, the alignment marker 2 on the microlens substrate 5 side is used.
Has a lens form (a lens function for enlarging an object in the focal point), the image of the alignment marker 3 on the driving substrate 6 is optically enlarged, and the alignment marker 3 on the driving substrate is instantly recognized. did it.

Furthermore, since the height of the lens vertex of the microlens 4 and the height of the vertex of the alignment marker 2 are almost equal, the depth of focus between the lens vertex of the microlens and the vertex of the alignment marker is almost the same, and highly accurate alignment is performed. I realized it. Thus, the microlenses 4 could be accurately arranged at positions corresponding to the respective pixels surrounded by the light shielding layer 7. When these were connected to a drive circuit and driven as a liquid crystal projector, the incident light was efficiently condensed by the microlenses 4 and a bright display image without luminance unevenness could be obtained.

(Second Embodiment) A second embodiment is shown in FIG.
A liquid crystal display comprising a drive substrate 6 having an alignment marker 3 having a shape in which four squares are arranged as shown in FIG. 1 and a microlens substrate 5 having an alignment marker 2 realizing high-precision alignment with respect to the drive substrate Related to the device.

As in the first embodiment, an electrode layer is formed, a first mask layer is formed, an opening is formed, a first plating layer is formed, and a first plating layer is formed.
Of the mask layer is performed. Next, a positive photoresist (AzP4620: manufactured by Client) is applied, exposed,
A second mask layer 13 as shown in FIG. 6 is provided on the first plating layer 12 that has been developed and has grown to a position corresponding to the 1064 × 808 regions excluding the peripheral portion of the array and the alignment markers. As a result, the first plating layer 12 at the periphery of the array is exposed.

The first plating layer 12 made of nickel exposed from the second mask layer is removed by etching using an etching solution. Thereby, the first plating layer 12 made of nickel exposed from the second mask layer can be completely removed. Next, by removing the second mask layer 13 with acetone and N, N-dimethylformamide, 1064 × 8
An array of 08 first plating layers 12 and an alignment marker structure can be formed. At this time, the first plating layer 1
The in-plane distribution of the radius 2 was within 5%.

Next, Ni is electrolessly plated at a bath temperature of 90 ° C. using an electroless Ni plating solution (Alnic PX, manufactured by Pax) containing a reducing agent for hypophosphite to form a second plating layer 14. To form Thereby, the first plating layer 1
2 is firmly fixed on the electrode layer, and a high gloss microlens mold or mold master can be obtained by using electroless plating for forming the second plating layer. The radii of curvature in the diagonal direction and the horizontal direction of each plating layer are almost equal, the average radius of curvature is 20 μm, and the distribution of the radius of curvature is ± 1.
A mold master having a uniform shape within a range of μm or less could be formed. Further, the in-plane distribution of the height of the plating layer in the microlens group and the plating layer corresponding to the alignment marker 2 was within 5%.

Thereafter, in the same manner as in the first embodiment, a mold is formed to produce a flat microlens substrate. The flat microlens substrate obtained here has a shape in which the depth and curvature of the concave portion of the alignment marker in the microlens group and the non-display area are substantially equal, and the concave portion of the transparent material is filled with a transparent material having a high refractive index. are doing.

Subsequently, the microlens alignment marker 2 is aligned with the driving substrate alignment marker 3 using an aligner, and the attachment is performed by relatively moving the driving substrate 6 and the microlens substrate 5. At this time, the alignment marker 2 on the microlens substrate side is also used.
Has a lens form, the image of the alignment marker 3 on the driving substrate is optically enlarged, and the alignment marker 3 on the driving substrate can be instantaneously recognized. Furthermore, the alignment markers 2 on the microlens substrate side have a spherical shape in a row and the rows intersect at right angles, which is suitable for overlapping with the alignment marker 3 on the drive substrate side having four squares arranged side by side. (See FIG. 5).

Further, since the height of the lens vertex of the microlens and the height of the alignment marker are substantially equal, the depth of focus between the lens vertex of the microlens and the vertex of the alignment marker is substantially equal, thereby realizing highly accurate alignment. did it. As a result, the microlens 4 could be accurately arranged at a position corresponding to each pixel. When these were connected to a drive circuit and driven as a liquid crystal projector, the incident light was efficiently condensed by the microlenses 4 again, and a bright display image without luminance unevenness was obtained.

[0048]

As described above, according to the present invention,
The relative displacement between the microlens and the alignment marker in the microlens substrate was eliminated, and the size of each lens in the microlens area could be made equal. Therefore, it was possible to prevent image quality deterioration such as uneven brightness. Further, since the alignment marker on the microlens substrate has a lens form, the alignment marker on the driving substrate can be instantaneously recognized, and the bonding time can be reduced. In addition, it is possible to provide a liquid crystal display device capable of preventing a decrease in a pixel aperture ratio and a light-collecting rate due to an inaccurate bonding between the driving substrate and the microlens substrate and improving a light-collecting efficiency.

[Brief description of the drawings]

FIG. 1A is a side view showing an embodiment of a liquid crystal display device according to the present invention, in which a microlens substrate and a driving substrate are superimposed, and FIG. 1B shows a microlens substrate. FIG. 3C is a top view illustrating the driving substrate.

FIG. 2 is a side view showing a mold or a mold master for producing the microlens substrate of the present invention.

FIG. 3 is a side view showing a method for manufacturing an example of a mold for a microlens or a mold master of the present invention.

FIG. 4 is a top view showing a mold or a mold master for a microlens array according to the first embodiment.

FIG. 5A is a top view illustrating a microlens substrate according to a second embodiment, and FIG. 5B is a top view illustrating a driving substrate.

FIG. 6 is a top view showing a mold or a mold master for a microlens array according to a second embodiment.

[Explanation of symbols]

 Reference Signs List 1 liquid crystal display device 2 alignment marker on microlens substrate side 3 alignment marker on drive substrate 4 microlens 5 microlens substrate 6 drive substrate 7 light-shielding layer 8 substrate 9 electrode layer 10 first mask layer 11 opening 12 first Plating layer 13 Second mask layer 14 Second plating layer 15 Structure for alignment marker

Claims (7)

[Claims] In a microlens substrate provided with an alignment marker serving as a reference for superposition with an alignment marker of another element, the microlens group and the alignment marker of the microlens substrate are formed in a concave portion of a transparent material. On the other hand, a microlens substrate formed by being filled with a transparent material having a higher refractive index than that of the microlens group, wherein the depth and curvature of the concave portion of the concave portion forming portion of the microlens group and the alignment marker are substantially equal. 2. The microlens substrate according to claim 1, wherein the alignment marker comprises a single microlens and has a lens form. 3. The microlens substrate according to claim 1, wherein the alignment marker is formed of a set of microlenses and has a lens form. 4. The microlens substrate according to claim 1, wherein the alignment marker has a lens shape and is composed of an assembly in which microlenses are arranged in a cross shape. 5. The liquid crystal display device according to claim 1, wherein the alignment marker is formed of an assembly in which microlenses are arranged in a line, and has a lens form. 6. The microlens substrate according to claim 1, wherein the alignment marker is formed of an aggregate of microlenses arranged in two rows and has a lens form. 7. A driving substrate including a pixel portion including a plurality of pixels and an alignment marker provided as a reference for superposition, a microlens group provided corresponding to the pixel portion of the driving substrate, and the driving substrate. 7. A liquid crystal display device comprising: the microlens substrate according to claim 1, further comprising: an alignment marker serving as a reference for superposition with the alignment marker. A liquid crystal display device, wherein the liquid crystal display device is disposed so as to face a predetermined interval.