JP2003330006A - Method for manufacturing liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rational and practicable method for manufacturing a liquid crystal display element equipped with a dual microlens structure. <P>SOLUTION: In the dual microlens structure, a microlens array consisting of two-dimensionally arrayed microlenses condensing light to respective pixels is integrally formed on one substrate and another microlens array consisting of two-dimensionally arrayed microlenses functioning as field lenses for the respective pixels is integrally formed on the other substrate. The microlens array is integrated into a rear surface of the substrate via a step to stick a mounting glass 2 to a surface 1f of a substrate 1, a step to grind a rear surface 1b of the substrate 1 in a state of being held on the mounting glass 2 so as to reduce thickness, a step to laminate the microlens array 4 on the ground rear surface 1b via a high-refractive-index transparent optical resin 5 and a step to release the mounting glass 2 from the surface 1f of the substrate 1 and to clean the surface 1f. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display element used as a light valve for a projector or the like. More specifically, it relates to a method of integrally forming microlenses corresponding to pixels on a substrate of a high-density and high-definition liquid crystal display element.

[0002]

2. Description of the Related Art FIG. 24 shows a schematic configuration of an optical system (mainly an illumination optical system) of a conventional projection type display device. This projection type display device includes a light source 101 along an optical axis 100.
A first microlens array 102, a second microlens array 103, a PS synthesizing element 104, a condenser lens 105, a field lens 106,
It has a structure in which a liquid crystal panel 107 and a projection lens 108 are sequentially arranged. Micro lens array 102, 1
In 03, a plurality of minute lenses (microlenses) 102M and 103M are two-dimensionally arranged.
The PS synthesis element 104 includes the second microlens array 1
A plurality of half-wave plates 104A are provided at positions corresponding to between the adjacent microlenses 03.

In this projection type display device, the light for illumination emitted from the light source 101 is supplied to the microlens array 10.
By passing through 2, 103, it is divided into a plurality of small luminous fluxes. The light that has passed through the microlens arrays 102 and 103 then enters the PS synthesizing element 104. The light L10 incident on the PS combining element 104 includes P-polarized light components and S-polarized light components that are orthogonal to each other in a plane perpendicular to the optical axis 100. The PS combiner 104 separates the incident light L10 into two types (P-polarized light component and S-polarized light component) of polarized light L11 and L12. The separated polarized light L11,
One of the polarized lights L11 of L12 is emitted from the PS synthesizing element 104 while maintaining its polarization direction (for example, P-polarized light). The other polarized light L12 (for example, S-polarized component) is
By the action of the half-wave plate 104A, it is converted into another polarization component (for example, P polarization component) and emitted. This allows
The polarization directions of the two separated polarized lights L11 and L12 are aligned in a specific direction.

The light emitted from the PS synthesizing element 104 passes through the condenser lens 105 and the field lens 106 and is applied to the liquid crystal panel 107. Each small luminous flux divided by the microlens arrays 102 and 103 is magnified at a magnification rate determined by the focal length fc of the condenser lens 105 and the focal length f of the microlens 103M provided in the second microlens array 103, and the liquid crystal panel. 10
Irradiate the entire incident surface of No. 7. As a result, the liquid crystal panel 1
A plurality of expanded light beams are superposed on the entrance surface of 07,
Uniform lighting is achieved overall. The liquid crystal panel 107 is
The incident light is spatially modulated according to the image signal and emitted. The light emitted from the liquid crystal panel 107 is projected by the projection lens 10
The image is projected onto a screen (not shown) by 8 to form an image on the screen.

FIG. 25 is a schematic perspective view showing an example of a liquid crystal panel. As shown in the figure, this liquid crystal panel (liquid crystal display element) has a flat panel structure including a pair of substrates 201 and 202 and a liquid crystal 203 held between them. A pixel array section 204 and a driving circuit section are integrally formed on the lower substrate 201. The drive circuit section is divided into a vertical drive circuit 205 and a horizontal drive circuit 206.
Further, a terminal 207 for external connection is formed on the upper end of the peripheral portion of the substrate. Each terminal 207 is connected to a vertical drive circuit 205 and a horizontal drive circuit 206 via a wiring 208. A gate line G and a signal line S are formed in the pixel array section 204. A pixel electrode 209 and a thin film transistor (TFT) 210 that drives the pixel electrode 209 are formed at the intersection of the two. A pixel P is configured by a combination of the pixel electrode 209 and the thin film transistor 210. Thin film transistor 21
The gate electrode of 0 is connected to the corresponding gate line G, the drain region is connected to the corresponding pixel electrode 209, and the source region is connected to the corresponding signal line S. The gate line G is connected to the vertical drive circuit 205, while the signal line S is connected to the horizontal drive circuit 206. The vertical drive circuit 205 is
Each pixel P is sequentially selected via the gate line G. The horizontal drive circuit 206 writes an image signal to the selected pixel P via the signal line S. In this way, the lower substrate 201 on which the pixel electrodes and thin film transistors (TFTs) are integrated and formed.
Is called a TFT substrate. On the other hand, a counter electrode and a color filter (not shown) are formed on the upper substrate 202. Therefore, the upper substrate 202 is called a counter substrate.

[0006]

When the above-mentioned active matrix type liquid crystal display element is used for a light valve of a projection type display device (projector), further higher definition and higher brightness are desired. From this viewpoint, a high-temperature polysilicon thin film transistor capable of high definition is used as a switching element for driving each pixel. or,
With the miniaturization of switching elements, miniaturization of microlens arrays is also required. As part of this, a technique for integrally forming a microlens array on a substrate of an active matrix type liquid crystal display device has been developed. Such a method of manufacturing a substrate with a built-in microlens is disclosed in, for example, JP-A-5-341283 and JP-A-10-161097.
Japanese Patent Laid-Open Publication No. 2000-147500.

As a method capable of achieving the highest brightness structurally, a microlens array functioning as a condenser lens is incorporated in the counter substrate on the light incident side, and a microlens array functioning as a field lens is incorporated in the TFT substrate side. However, the so-called dual microlens structure is ideal. Such a dual microlens structure can increase the effective aperture ratio of a pixel to the maximum.
However, the degree of workability is the highest, and a practical manufacturing method has not been established at this time. The LCD with this dual microlens structure is a Microlens Substrat.
e-TFT Substrate-Microlens Substrate is also called MTMLCD.

[0008]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, it is an object of the present invention to provide a rational and practical manufacturing method of a liquid crystal display device having a dual microlens structure. The following measures have been taken in order to achieve this purpose. That is, a substrate having a surface on which at least a pixel electrode and a switching element for driving the pixel electrode are formed and a back surface on the opposite side, and a substrate having at least a surface on which a counter electrode is formed and a back surface on the opposite side. , A panel structure having a liquid crystal layer disposed between both substrates, in which the pixel electrode and the counter electrode are bonded to face each other with a predetermined gap, and one pixel electrode is provided on each substrate. A microlens array in which microlenses that collect light are two-dimensionally arranged is integrally formed, and on the other substrate, microlenses preferably functioning as field lenses are two-dimensionally arranged for each pixel electrode. In a method of manufacturing a liquid crystal display element in which the microlens array is integrally formed, a bonding step of bonding a base plate to the surface of the substrate and a back surface of the substrate while being held by the base plate. By a polishing step to reduce the wall thickness by polishing, a bonding step of bonding a microlens array to the polished back surface via an optical resin, and a peeling step of peeling the base plate from the surface of the substrate. The microlens array is integrated on the back surface of the substrate.

Preferably, the surface substrate having an area corresponding to a plurality of panels is previously subjected to the adhering step, the polishing step, the laminating step, and the peeling step to form a plurality of microlens arrays on the surface substrate. After the above are integrated, a dividing step is performed at an appropriate stage to separate the single substrate corresponding to each panel. For example, after forming a plurality of microlens arrays on one surface substrate, immediately perform the dividing step to separate into one single substrate corresponding to each panel,
The microlens array is integrated with the other single substrate in advance in a one-to-one superposition with a predetermined gap, and assembled into a panel. Alternatively, after forming a plurality of microlens arrays on one surface substrate, the other single substrate in which the microlens arrays are integrated in advance is individually superposed on the surface substrate at a predetermined gap, and then the dividing step is performed. It is also possible to carry out to separate into individual panels. Alternatively, one surface substrate having a plurality of microlens arrays integrated therein and the other surface substrate having a plurality of microlens arrays integrated together are overlapped at a predetermined gap to form a plurality of panels. After assembling, the panel may be divided into individual panels by performing the dividing step. In these cases, in the dividing step, the first dicing is performed along the boundary that divides the surface substrate into individual panels to form a groove having a V-shaped cross section, and then the second dicing is performed to complete the groove. It is recommended that the single substrate is cut into pieces and the end faces thereof are tapered. Further, after the base plate is peeled and washed from the surface of the substrate by the peeling step, the liquid crystal layer is aligned with respect to the exposed surface of the substrate within a temperature range that does not impair the heat resistance of the microlens array previously integrated. An alignment process for forming an alignment layer for the purpose is performed. Alternatively, the bonding step, the polishing step,
Before performing the bonding step and the peeling step to integrate the microlens array on the back surface of the substrate, an alignment step of previously forming an alignment layer for aligning the liquid crystal layer with respect to the front surface of the substrate may be performed.

Preferably, the polishing step is performed by buff optical polishing, powder injection, chemical mechanical polishing and chemical etching, either alone or in combination. Further, in the polishing step, the substrate is polished to reduce the thickness so that the focus of the microlens functioning as a field lens at the stage of assembling into the panel is substantially coincident with the principal point of the microlens functioning as a condenser lens. Shave. In addition, the laminating step,
A step of processing a resin material having a relatively low refractive index to form a microlens array in which each microlens surface is two-dimensionally arranged, and a back surface of the polished substrate and the microlens array are overlapped between the two. And a process of filling and curing an optical resin having a relatively high refractive index. In this case, in the laminating step, the back surface of the polished substrate and the microlens array are adhered with a sealant to form a closed void, and the void is filled with an optical resin. Further, the microlens surface is processed into a spherical surface, an aspherical surface or a Fresnel surface.
In some cases, the method includes a cleaning step of cleaning the base plate that has been used and has been peeled off in the peeling step and reused.

According to one embodiment, a pre-process of integrating a microlens array on a first substrate on which a counter electrode is formed in advance, and a second process in which a pixel electrode and a switching element for driving the pixel electrode are formed in advance. An assembling step of assembling a panel by superimposing a first substrate on which the microlens array is integrated on a surface of the substrate at a predetermined gap, the adhering step including the second substrate through the first substrate. A base plate is adhered to the front surface side of the substrate, the polishing step polishes the back surface of the second substrate while the panel is held by the base plate, and the laminating step includes the polished second substrate. Attach the microlens array to the back of the. In this case, in the polishing step, the back surface of the second substrate may be polished with the plurality of external connection terminals formed on the second substrate held at the same potential. In some cases, in the adhering step, the first substrate side of the panel is attached to a base plate that is fixed to a polishing plate used in the polishing step in advance.

According to the present invention, for example, a base plate is attached to the front surface of the TFT substrate with an adhesive or the like, and one side is optically polished from the back surface of the TFT substrate to form a TFT thin substrate having a predetermined thickness.
A microlens substrate is attached to this with, for example, a transparent resin adhesive having a high refractive index, to form a TFT substrate with a built-in microlens. A TFT substrate with a built-in microlens, in which microlenses are integrated, is created by the same process. A liquid crystal display element having a dual microlens structure is produced by stacking the TFT substrate with a built-in microlens and the counter substrate with a built-in microlens at a predetermined gap, and injecting and sealing a liquid crystal between them. The dual microlens type liquid crystal display element manufactured as described above is suitable for a light valve of a projector, for example. One microlens array that functions as a condenser lens and the other microlens that functions as a field lens can be placed extremely close to the liquid crystal layer, and the microlens function can be maximized to maximize the effective aperture of a pixel. The rate can be greatly improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a basic manufacturing process diagram showing a method of manufacturing a liquid crystal display element according to the present invention. First, as shown in (A), a bonding process is performed to form the TFT substrate 1.
The base plate such as the base glass 2 is adhered to the surface 1f of the base plate 1 via the adhesive 3. When the base glass 2 is attached to the TFT substrate 1, an adhesive 3 that dissolves in water or an organic solvent can be used. As an adhesive of this type, a hot-melt water-soluble solid wax (for example, Aqua Wax 20/50/80 (main component is fatty acid glyceride) of Nikka Seiko Co., Ltd., Aqua Wax 553/531/442 / SE (mainly Component is polyethylene glycol, vinylpyrrolidone copolymer, glycerin polyether), PEG wax 20 (main component is polyethylene glycol), etc.} or water-soluble liquid wax {for example, synthetic resin liquid adhesive of Nikka Seiko Co., Ltd. Aqua Liquid WA-302 (main component is polyethylene glycol, polyvinylpyrrolidone derivative, methanol), WA-20511 / QA-20566 (main component is polyethylene glycol, polyvinylpyrrolidone derivative, I)
PA, water, etc.), or a crystal bond of a thermoplastic polymer, a cyanoacrylate adhesive, an epoxy adhesive, or the like. In some cases, the TFT substrate 1 and the base glass 2 may be attached to each other with a double-sided tape of an ultraviolet curable adhesive or a double-sided tape of a heat-curable adhesive. If necessary, a resist film may be coated on the surface 1f of the TFT substrate 1 to protect the surface and prevent halogen ion contamination. The base glass material may be transparent glass such as borosilicate glass and soda lime glass.

For example, when "Crystal Bond", which is a thermoplastic polymer, is used as the adhesive 3 that dissolves in an organic solvent such as acetone, a solution in which crystal bond is dissolved in acetone is applied to the base glass 2 to form the TFT substrate 1. Overlapping, 150-160 ℃ / 133322Pa (0.1
It is heated under vacuum under the condition of (torr) to defoam bubbles existing between the two and bring them into close contact. After that, degassing is further promoted by the pressure when returning to atmospheric pressure by breaking the vacuum, and the thickness of the adhesive 3 is made uniform, for example, 1 μm to 3 μm.
And In addition, a hot-melt water-soluble solid wax (for example, Aqua Wax 80/553 manufactured by Nika Seiko Co., Ltd., PE
In case of G wax 20, etc.), 30 to 4 in methanol
A solution obtained by melting 0% by weight, filtering and removing foreign matter was spin-coated on a base glass, the TFT substrate 1 was overlaid, and
Vacuum heating is carried out under the condition of 00 ° C./13.3322 Pa (0.1 torr) to remove air bubbles existing between the two and bring them into close contact. After that, degassing is further promoted by the pressure when returning to atmospheric pressure by breaking the vacuum, and the thickness of the adhesive 3 is made uniform, for example, 1 μm to 3 μm. Further, in the case of a water-soluble liquid wax (for example, Aqua Liquid WA-302 manufactured by Nika Seiko Co., Ltd.), for example, the liquid having a viscosity of 4 to 5 cP is spin-coated on a base glass, and the TFT substrate 1 is overlaid. , 70-80 ° C / 13.3322Pa
Vacuum heating is performed under the condition of (0.1 torr) to remove air bubbles existing between the two and bring them into close contact. After that, defoaming is further promoted by the pressure when returning to atmospheric pressure by breaking the vacuum, and the thickness of the adhesive 3 is made uniform, for example, 1 μm to
3 μm.

Instead of this, a polyolefin tape (thickness 100 ± 2 μm) formed with an ultraviolet curable adhesive (thickness 10 ± 1 μm) on both sides or a polyolefin tape (thickness 100 ± 2 μm) formed with a heat-curable adhesive on both sides )
Then, the base glass 2 and the TFT substrate 1 may be bonded. At this time, vacuum defoaming treatment may be performed so that bubbles are not generated between the two.

Subsequently, as shown in (B), a polishing step is performed, and the back surface 1b of the TFT substrate 1 is polished while being held by the base glass 2 to reduce the thickness. For example, the TFT substrate 1 having a predetermined thickness (for example, 20 ± 3 μm) is formed by subjecting the TFT substrate 1 to the one-sided optical polishing from the back surface 1b with reference to the base glass 2.
To create. At this time, the dimensional accuracy of the base glass 2 has a parallelism of 1 to 3 μm and a thickness of 2 mm. As a polishing method,
One side buff optical polishing can be adopted. In this case, rough polishing, intermediate polishing, and final polishing are performed in this order, and the particle size of the abrasive such as alumina and cerium oxide is reduced accordingly to improve the surface accuracy. The single-sided powder injection processing and the single-sided buff optical polishing may be combined. In the jetting process, a constant amount of a phase flow, in which powder particles made of an abrasive such as silicon carbide, boron carbide, diamond, etc. are dispersed in high pressure air, is jetted from a slit-shaped jet port on the tip side of the nozzle, and the TFT substrate 1 Back side 1b
Irradiation and polishing are performed while reciprocally scanning over the entire length. After that, buff optical polishing is used to further improve the surface accuracy and to remove residual stress by spraying powder particles. Or CM
Single-sided optical polishing may be performed by P (chemical mechanical polishing).
In this case, it is preferable to perform rough polishing, intermediate polishing, and final polishing in the same order as in single-sided buffing optical polishing. Alternatively, single sided glass etching and single sided buff optical polishing may be combined. At this time, the TFT substrate 1 is thinned to some extent by glass etching with a hydrofluoric acid-based etching solution to a predetermined thickness. Surface waviness caused by glass etching is removed by final polishing of buff optical polishing. It is necessary to use a protective adhesive or tape that withstands hydrofluoric acid based etchants. Alternatively, single-sided glass etching and single-sided optical etching by CMP may be combined. First, the back surface 1b of the TFT substrate 1 made of quartz glass or the like is glass-etched to a predetermined thickness with a hydrofluoric acid-based etching solution, and the remaining surface waviness is removed by single-sided optical polishing by CMP. In this case as well, it is necessary to use a protective adhesive or tape that withstands the hydrofluoric acid-based etching solution.

Next, a laminating step is performed as shown in (C),
The microlens array is attached to the polished back surface 1b of the TFT substrate 1 with the optical resin 5 interposed therebetween. Specifically, a process of processing an optical glass such as quartz glass or neoceram to form a microlens substrate (ML substrate) 4 in which each microlens surface 4r is two-dimensionally arranged, and a polished TF.
The back surface 1b of the T substrate 1 and the ML substrate 4 are aligned and superposed, and a transparent optical resin 5 having a higher refractive index than the substrate is filled and cured between them. In this case, the back surface 1b of the TFT substrate 1 and the ML substrate 4 are inserted via the sealing material 6.
Are bonded to form a closed void, and the transparent optical resin 5 having a high refractive index is filled and sealed in the void.

Specifically, a frame of the sealing material 6 having an injection port is formed around the ML substrate 4. The thinned TFT substrate 1 and the ML substrate (microlens substrate) 4 are superposed with a predetermined gap, and the sealing material 6 is fixed.
When the sealing material is a thermosetting adhesive, it is cured at a predetermined temperature. When using a UV radiation curable adhesive,
It is cured by irradiation with the specified ultraviolet rays. An adhesive that uses both UV irradiation and heat curing is subjected to predetermined UV irradiation and heating. After that, the transparent optical resin 5 having a high refractive index is injected and sealed from the injection port, and is cured by heating. At this time, the liquid high-refractive-index transparent resin 5 is injected through the injection port, and the injection port is sealed with an ultraviolet curable adhesive. For example, an acrylic or acrylic epoxy high-refractive-index transparent resin has a viscosity of 20 to 100C.
PS, which is dispense coating or dipping in a vacuum and is injected at the pressure for returning to atmospheric pressure. At this time, if necessary, the pressure may be appropriately increased. By curing this high-refractive-index transparent optical resin at 70 to 80 ° C. for 120 minutes, the high-refractive-index transparent optical resin 5 having a refractive index of 1.59 to 1.67 can be obtained. By filling and hardening the lens surface 4r formed on the microlens substrate 4 having a relatively low refractive index with the optical resin 5 having a high refractive index, it is possible to automatically create the microlens. In order to align the pixel electrode formed on the TFT substrate 1 and the lens surface 4r formed on the microlens substrate 4 side by side, the alignment marks formed on both the TFT substrate and the ML substrate are overlapped. Then, both are fixed by the sealing material 6.

Subsequently, as shown in (D), a stripping step is performed to strip the used base glass from the surface 1f of the TFT substrate 1. Thereby, the back surface 1b of the TFT substrate 1
The microlens array can be integrated into the. Specifically, the base glass is T
It can be peeled from the FT substrate 1. When the adhesive is a thermoplastic polymer crystal bond or a cyanoacrylate adhesive, the base glass is heated and peeled off, and then the whole is acetone, acetone + ethanol, methanol, IP
Ultrasonic cleaning with an organic solvent such as A. When the adhesive is a hot-melt water-soluble wax (for example, Aqua Wax 80/553, PEG wax 20 manufactured by Nika Seiko Co., Ltd.), ultrasonic cleaning is performed with pure water or warm pure water at 50 to 60 ° C. Incidentally, it is desirable to reuse the used high-precision base glass after cleaning.

Finally, as shown in (E), one-side polished T
Microlens TFT substrate (MLTFT substrate) 7 formed by integrating FT substrate 1 and microlens substrate 4
Similarly, a microlens counter substrate (ML counter substrate) 17 obtained by integrating the microlens substrate and the counter substrate together.
And the sealing material 8 are overlapped with each other with a predetermined gap,
The liquid crystal 9 is injected and sealed between the two, and an active matrix type liquid crystal display element having a dual microlens structure is completed. The microlens counter substrate 17 can be formed by the same process as the microlens TFT substrate 7. That is, the surface side of the counter substrate 11 is polished, and the microlens substrate 14 is bonded to this with the sealing material 16 interposed therebetween. A microlens surface 14r is previously formed on the microlens substrate 14. The ML counter substrate 17 is completed by filling and hardening the optically transparent resin 15 having a high refractive index between the one-side-polished counter substrate 11 and the microlens substrate 14. A counter electrode is previously formed on the surface of the counter substrate 11 which is in contact with the liquid crystal 9.

The present liquid crystal display element has a panel structure in which the liquid crystal 9 is held between the pixel electrode formed on the MLTFT substrate 7 side and the counter electrode formed on the ML counter substrate 17 side. On the ML counter substrate 17 side, a microlens array in which microlenses that collect light are two-dimensionally arrayed is integrally formed on each pixel electrode. On the MLTFT substrate 7 side, a microlens array in which microlenses functioning as field lenses are similarly two-dimensionally arranged for each pixel electrode is integrally formed. In the polishing process described above, T is set so that the focal point of the microlens functioning as a field lens at the stage of assembling into the panel is substantially coincident with the main point of the microlens functioning as a condenser lens.
The FT substrate 1 and the counter substrate 11 are polished to reduce the wall thickness. For example, the TFT substrate 1 is thinned to about 20 μm, and the above-mentioned conditions can be satisfied. By arranging the focal point of the field lens so as to substantially coincide with the principal point of the condenser lens in this way, it becomes possible to maximize the effective aperture ratio of the pixel. As the pixel becomes finer, the focal point of the microlens becomes shorter, and the thickness of each substrate needs to be made considerably thin accordingly. At that time, by applying the present invention, the thinning of the TFT substrate or the counter substrate can be achieved reasonably and efficiently. The lens surfaces 4r and 14r of the microlens can be processed into spherical surfaces, aspherical surfaces or Fresnel surfaces. A spherical lens is advantageous in terms of processing, but since the radius of curvature that minimizes the focal length is restricted by the pixel size, it is difficult to achieve a short focus unless a sufficient refractive index difference at the lens interface can be secured. The aspherical surface and the Fresnel surface are excellent in terms of short focal length of the lens and flatness of the main surface of the lens, and a lens shape having a high effect of suppressing the divergence angle of the light from the light source can be formed.

FIG. 2 is a process chart showing an embodiment of a method for manufacturing a liquid crystal display element according to the present invention. In this embodiment, the process is rationalized by using a large-area TFT substrate (TFT large substrate) capable of multiple cutting. A large area substrate is used up to a predetermined process, and is cut into a single substrate corresponding to each panel in a later process. In the figure, (plane) represents a multi-face process, and (single) represents a single face process. First, in step S1, a large TFT substrate is prepared. Its dimensions are, for example, 8 inches in diameter. In step S2, an 8-inch base glass is attached to the large TFT substrate. In step S3, single-sided optical polishing is performed to reduce the thickness of the TFT large substrate to 20 μm. In step S4, an 8-inch ML substrate prepared in advance is attached to a TFT large substrate that has been polished on one side with a high refractive index resin. Subsequently, in step S5, the used base glass is peeled and washed.

Then, in step S6, an alignment treatment is applied to the exposed front surface of the large TFT substrate. For example, a rubbing process is performed after forming a polyimide alignment film on the surface of a large TFT substrate. At this time, since a high refractive index resin having relatively low heat resistance is incorporated in the previous step, it is preferable to use a low temperature polyimide alignment film in the alignment treatment in step S6.
However, recent polyimide resins often cure at a relatively low temperature, and it is not always necessary to use a low-temperature polyimide alignment film. In some cases, a DLC (diamond-like carbon) film may be formed instead of the polyimide alignment film, and the alignment treatment may be performed by ion irradiation treatment having directivity. Alternatively, the orientation treatment may be performed by oblique vapor deposition of SiO _x . In a specific alignment treatment, an alignment film made of polyimide or the like is formed by roll coating, spin coating, or the like, and rubbing alignment treatment with a buff material is performed. Alternatively, a DLC film is formed to a thickness of about 5 nm and orientation treatment is performed by directional ion irradiation. Or SiO film 5
Orientation treatment is performed by oblique vapor deposition with a film thickness of 0 nm. Thereafter, in step S7, the 8-inch TFT large substrate is divided into individual 0.9-inch square single substrates. For example, the TFT large substrate can be divided by dicing or carbon dioxide laser. As a result, a TFT substrate with a built-in microlens is obtained.

Finally, a good TFT with a built-in microlens
A substrate and a counter substrate with a built-in microlens, which is also a good product, are superposed at a predetermined gap, and a liquid crystal material such as nematic liquid crystal is injected into the gap, and the injection port is sealed. Specifically, a frame of a sealing material having an injection port is formed around one of the microlens-containing TFT substrate and the microlens-containing counter substrate. Micro lens built-in T
The FT substrate and the counter substrate with a built-in microlens are superposed with the alignment marks provided on both, and the sealing material is fixed. After injecting liquid crystal through the injection port, the injection port is sealed with an ultraviolet irradiation adhesive. After that, the liquid crystal is heated and rapidly cooled for alignment treatment.

As described above, in this embodiment, the adhering step, the polishing step, the laminating step and the peeling step are performed on the surface substrate having an area corresponding to a plurality of panels in advance,
After a plurality of microlens arrays are integrated with the surface substrate, a dividing step (step S7) of separating into a single substrate corresponding to each panel is performed at an appropriate stage. This makes it possible to rationalize the manufacturing process.
In this embodiment, after forming a plurality of microlenses on one surface substrate, a dividing step is immediately performed to separate the microlens array into one single substrate corresponding to each panel, and the microlens array is integrated in advance. One of the single substrates is superposed one on one with a predetermined gap, and assembled into a panel (step S8). Further, in this embodiment, after the base glass is peeled and washed from the surface of the substrate in the peeling step (step S5), the exposed surface is first subjected to step S4.
The orientation layer for orienting the liquid crystal layer is formed in a temperature range that does not impair the heat resistance of the microlens array integrated with each other (step S6).

FIG. 3 is a schematic diagram showing a specific method of the dividing step (step S7) shown in FIG. In this dividing step, a large substrate is divided by dicing or a carbon dioxide gas laser, etc.
The FT substrate is prepared, and the two-stage method is adopted as shown in the figure. In the first stage shown in FIG.
A first dicing is performed along the boundary dividing the panel into individual panels to form a groove having a V-shaped cross section. Therefore, the V-cut dicing blade 21 is used. Further, in the second stage shown in (B), the second dicing is performed using the normal dicing blade 22 to completely cut the groove and separate each panel. As a result, it is possible to create a single substrate whose end face is tapered. By chamfering the V-cut groove in this way and then performing full-cut dicing, chamfering is possible. When the single substrate thus chamfered is assembled into a panel, it is possible to prevent end face cracks and cracks of the TFT thin substrate. In addition, it is desirable that the first and second dicing be performed continuously using a dual dicer.

FIG. 4 is a process chart showing another embodiment of the method for manufacturing a liquid crystal display element according to the present invention. The difference from the previous embodiment shown in FIG. 2 is that steps S7 and S8 are reversed. That is, in the present embodiment, a non-defective product in the large ML built-in TFT substrate which has been subjected to the orientation treatment is subjected to the orientation treatment.
The non-defective products of the opposite substrate are stacked and assembled individually (step S7). After the liquid crystal injection and sealing, the large ML built-in TFT substrate is divided in step S8 to obtain individual panels. Compared with the previous embodiment shown in FIG. 2, it is more rational because a multi-faceted process can be adopted until just before the final stage. As described above, in the present embodiment, after forming a plurality of microlens arrays on one surface substrate, the other single substrate in which the microlens arrays are integrated in advance is individually assembled to the surface substrate (step S7). Thereafter, a dividing step (step S8) is performed to separate the panels.

FIG. 5 is a schematic diagram showing a specific method of the assembling step S7 shown in FIG. As shown in the figure, a non-defective single substrate 17 with built-in microlenses is superposed on a non-defective portion of the large TFT substrate 7 with microlenses at a predetermined gap, and is fixed with a sealing material 8. The liquid crystal 9 is placed in the gap between the two substrates 7, 17. Is sealed. Specifically, the MLTFT large substrate 7
UV-irradiation type or heat-curable sealing material 8 is applied to the ML counter substrate 17 and the MLTFT substrate 7 are aligned with each other by alignment marks provided at both sides and overlapped at a predetermined gap. Stick to it. After that, the liquid crystal 9 is injected, and the injection port is sealed with an ultraviolet irradiation type adhesive. After completing the assembling step S7 in this way, a dividing step is performed by dicing or laser in step S8. As indicated by the one-dot chain line, dicing is performed along the boundaries of each panel and the panels are separated. At that time, in order to prevent end face cracks and cracks of the thin TFT substrate 1, it is preferable to perform chamfering by V-cut and then full-cut dicing.

FIG. 6 is a process chart showing an example of a method for manufacturing the ML counter substrate 17 shown in FIG. As shown in (A), first, a frame is formed by the sealing material 16 around the ML substrate 14 in which the individual microlens surfaces 14r are formed in advance. The cover glass substrate 11 and the ML substrate 14 are overlapped with a predetermined gap, and the sealing material 16 is fixed. Thereafter, as shown in (B), the high-refractive-index transparent optical resin 15 is injected into the gap between the cover glass substrate 11 and the ML substrate 14 and heat-cured. Then, it is sealed with an ultraviolet radiation curable adhesive.
Further, the back surface of the cover glass substrate 11 is thinned by single-sided optical polishing to form the ML counter substrate 17. A transparent conductive film such as ITO is formed on the entire surface of the cover glass substrate 11 which is optically polished on one side to form the counter electrode 18. A polyimide alignment film 19 is formed on it, and an alignment treatment is performed by rubbing or the like. At this time, a cover glass substrate having a predetermined film thickness is formed by making the cover glass substrate thinner than the ML counter substrate 17 and performing double-sided optical polishing (optically polishing both sides of the ML counter substrate and the cover glass substrate simultaneously). May be. The microlens surface 14r is filled with a transparent resin having a high refractive index to form the ML substrate 14, a transparent resin film is formed on the surface of the ML substrate 14, and the S
The cost may be reduced in place of the cover glass substrate by stacking an iO ₂ sputter or vapor deposition film.
The single ML counter substrate 17 thus completed is assembled to the multi-faced type MLTFT large substrate 7 shown in FIG.

FIG. 7 shows another embodiment of the method of manufacturing a liquid crystal display device according to the present invention, which is an improved version of the previous embodiment shown in FIG. In the embodiment of FIG. 2, the microlens array is integrated in step S4, and then the alignment process is performed in step S6. In this case, in consideration of the heat resistance of the high refractive index resin that constitutes the microlens array,
In the orientation process, a low temperature polyimide film had to be used. On the other hand, in the present embodiment, step S2
In step S5, the microlens array is integrated after the alignment process is performed first. Therefore, it is not necessary to use a low temperature polyimide film in the orientation treatment, and a high temperature polyimide film having excellent performance and stability can be used. As described above, in this embodiment, before the microlens array is integrated with the back surface of the substrate by performing the bonding step, the polishing step, the bonding step, and the peeling step, the liquid crystal layer is aligned in advance with respect to the front surface of the substrate. The alignment step (step S2) of forming an alignment layer for the purpose is performed. A general polyimide film is cured at around 180 ° C., and a general high refractive index transparent resin is cured at a low temperature of 60 to 120 ° C. Therefore, it is not appropriate to form a general polyimide film on the TFT large substrate on which the microlenses of high refractive index transparent resin are mounted, and in the embodiment of FIG.
The C film was used as the alignment film. On the other hand, in this embodiment, since the alignment treatment is performed prior to the integration of the microlens array using the high refractive index resin, a high temperature film-forming type polyimide film that cures at around 180 ° C. is normally used. It is possible.

FIG. 8 is a process chart showing another embodiment of the method for manufacturing a liquid crystal display element according to the present invention. Basically, the same as the previous embodiment shown in FIG.
After the L counter substrate is assembled, it is divided into individual panels. The difference is that the alignment process (step S2) is performed first, and then the microlens array using a transparent optical resin having a high refractive index is integrated in step S5. By carrying out the orientation treatment in advance, a high temperature type polyimide film can be used as in the embodiment of FIG.

FIG. 9 is a process chart showing still another embodiment of the method for manufacturing a liquid crystal display element according to the present invention. In the present embodiment, in step S7, the MLTFT large substrate and the MLFT are
The opposing large substrate is assembled and then divided into individual panels in step S8. Since both large substrates are used until just before the final stage, the manufacturing process is further streamlined. However, the selection of non-defective products and defective products will be performed by a single product inspection after the final stage. As described above, in this embodiment, one surface substrate in which a plurality of microlens arrays is integrated and the other surface substrate in which a plurality of microlens arrays are integrated are also superposed at a predetermined gap. After assembling a plurality of panels (step S7), a dividing process is performed in step S8 to separate the panels. In this embodiment, the microlens array using the high refractive index transparent optical resin is first integrated in step S4, and then the alignment process is performed using the low temperature polyimide film or DLC in step S6. There is.

FIG. 10 is a process chart showing still another embodiment of the method for manufacturing a liquid crystal display element according to the present invention. Basically, it is similar to the embodiment shown in FIG. 9, and after the large substrates are bonded together, they are divided into individual panels. The difference is that the microlens array using a transparent optical resin having a high refractive index is integrated in step S5 after the alignment process is preceded in step S2. By allowing the orientation treatment to precede, it becomes possible to use a normal high temperature film-forming polyimide film.

FIG. 11 is a process chart showing still another embodiment of the method for manufacturing a liquid crystal display element according to the present invention. Unlike the previous embodiment, this embodiment basically assembles the panel by a single-sided process without adopting a multi-sided process. First, in step S1, a TFT large substrate having a diameter of 8 inches is formed, and then in step S2, dicing or division using a carbon dioxide gas laser is performed to form, for example, a 0.9 inch TFT single substrate. If necessary, a resist film for surface protection and halogen contamination prevention may be coated on the surface of the TFT substrate. Then, in step S3, T
Similarly, a 0.9 inch base glass is attached to the FT substrate. While the base glass is made of, for example, borosilicate glass,
The TFT substrate is made of synthetic quartz glass, for example. The parallelism of the base glass is 1 to 2 μm and is finished with high precision. The base glass and the TFT substrate are adhered to each other by a double-sided transparent tape made of a thermoplastic transparent polymer adhesive or an ultraviolet irradiation-curable adhesive or a double-sided transparent tape made of a thermosetting adhesive. Thereafter, in step S4, the back surface of the TFT substrate is optically polished on one side to reduce the thickness to 20 μm. The variation in the thickness of the TFT substrate is preferably suppressed within ± 3 μm. In step S5, the thinned TFT substrate and the microlens substrate (ML substrate) on which microlens surfaces are formed in advance are superposed, and a transparent optical resin having a high refractive index is injected and sealed. The ML substrate is also 0.9 inch in size. After this, the base glass is peeled off and washed in step S6. Since the base glass has a high precision finish, it will be reused. The base glass can be peeled by heating. After that, the substrate is washed with an organic solvent. Alternatively, it may be peeled off and washed after being cured by ultraviolet irradiation.
Further, in step S7, orientation processing is performed. For example, a polyimide alignment film for low temperature is formed, and a rubbing process with a buff material is performed. Alternatively, a DLC film may be formed and directed ion irradiation may be performed to form an alignment film. Finally, in step S8, a single ML counter substrate is similarly prepared, and this and the MLTFT substrate are stacked with a predetermined gap, and liquid crystal is injected and then sealed. For example, apply a frame to one substrate with an ultraviolet irradiation type sealing material, overlap the other substrate with a predetermined gap, align with the alignment marks provided on both, and irradiate ultraviolet rays to cure the sealing material, Fix the substrate. This gives an empty panel. A liquid crystal display element having a dual microlens structure is completed by injecting and sealing liquid crystal into an empty panel through an opening formed in a part of the sealing material.

FIG. 12 is a process chart showing still another embodiment of the method for manufacturing a liquid crystal display element according to the present invention. Basically, like the previous embodiment shown in FIG. 11, a single-sided process is adopted throughout. The difference is that the alignment process of step S3 precedes the bonding process using the transparent optical resin having a high refractive index of step S6.

FIG. 13 is a schematic view showing another embodiment of the method of manufacturing a liquid crystal display element according to the present invention. In this embodiment, in the previous step, the microlens array is integrated with the first substrate on which the counter electrode is formed in advance, and the ML counter substrate 1 is formed.
Create 7. After this, an assembly process is performed, and a counter substrate (ML counter substrate) 17 integrated with microlenses is superposed on the surface 1f of the TFT substrate 1 on which the pixel electrodes and the switching elements for driving the pixel electrodes are formed in advance with a predetermined gap. Liquid crystal is injected and sealed to assemble the panel. After that, a bonding step is performed to bond the base glass 2 to the front surface 1f side of the TFT substrate 1 via the ML counter substrate 17. At that time, as the adhesive 3, a hot melt type water-soluble wax, beeswax, a cyanoacrylate type adhesive or the like can be used. Alternatively, the base glass 2 is attached to the ML-embedded counter substrate 17 side with an adhesive obtained by diluting acrylate with a chlorine-free organic solvent (acetone, acetone and ethanol, IPA, etc.). After that, a polishing step is performed, and the back surface 1b of the TFT substrate 1 is polished while being held together with the panel on the base glass 2. After that, a laminating process is performed,
A microlens array is attached to the back surface 1b of the polished TFT substrate 1. Unlike the previous embodiment, this embodiment is characterized in that after the panel is first assembled, the rear surface of the TFT substrate is polished and the microlens array is integrated.

In the manufacturing method shown in FIG. 13, since the TFT substrate 1 on which the pixel electrodes and the thin film transistors are already formed is polished, it is preferable to take measures against electrostatic damage in advance. In the example of FIG. 14, a conductive material 24 having no adhesive residue is used as a countermeasure against static electricity damage. As shown in the drawing, the take-out terminal formed on the TFT substrate 1 is short-circuited with a tape having substantially the same thickness as the counter substrate 17 with a built-in microlens, in particular, a conductive adhesive tape having no adhesive residue, and the base glass 2 is fixed with an adhesive 3. is doing.

In the countermeasure against static electricity damage shown in FIG.
After the connector 26 made of a flexible printed circuit board for external connection is attached to the connection terminal of the TFT substrate 1 by thermocompression bonding, the base glass 2 is fixed by the adhesive 3 or the double-sided tape. Further, the adhesive is embedded in the gap formed between the base glass 2 and the TFT substrate 1, or a tape member 25 having substantially the same thickness as the counter substrate 17 with a built-in microlens is inserted to stabilize the connector 26. There is. Connector 2
The length of 6 is made short enough not to hinder the single-sided optical polishing of the TFT substrate 1 performed in a later step, and at the same time, its terminal is short-circuited and covered so as not to be contaminated with an abrasive or the like. Thus, in the polishing process of this embodiment, the TFT substrate 1
The back surface of the TFT substrate 1 is polished with the plurality of terminals for external connection formed at 1 held at the same potential as each other, thereby taking measures against electrostatic damage.

FIG. 16 is a schematic view showing the polishing process of the panel shown in FIG. As shown in the figure, the base glass 2 side of the panel is attached to a polishing work holder 29, and the back surface 1b of the TFT substrate 1 is polished based on the base glass 2. At this time, it is preferable to carry out one-side polishing while cooling so that the liquid crystal 9 sealed in the panel does not exceed the transition temperature. Thereby, the alignment state of the liquid crystal 9 can be maintained. In the illustrated example, single-sided buffing optical polishing is performed, the back surface 1b of the TFT substrate 1 is pressed against the polishing plate 27 with a constant load, and a fixed amount of polishing agent is constantly supplied to the polishing plate 27.

Specifically, a polishing plate 27 such as a tin plate, a vinyl plate, or a cross plate is rotated about its central axis,
A constant amount of liquid such as water, oil and organic solvent containing an abrasive such as silicon carbide, alumina and diamond is constantly dropped on the polishing plate 27, and the work fixed to the work holder 29 is applied to the polishing plate 27 and loaded. And the surface is polished. At this time, rough polishing, middle polishing, and final polishing are performed in order, and the particle size of the polishing agent is reduced accordingly to increase the surface accuracy. When the amount of processing is large, the workpiece is polished by rough polishing to a thickness close to the target, and then medium polishing and finish polishing are performed. For example, if the thickness of the TFT substrate 1 is 800 μm,
The thickness of the TFT substrate 1 is 20 μm after the rough polishing to 700 μm and the middle polishing to 750 μm.
And At this time, since the target of the thickness of the TFT substrate is 20 ± 3 μm, the final polishing is performed every 10 μm of polishing amount while confirming the remaining thickness with an optical or laser step depth measuring device based on the alignment mark reference on the surface of the TFT substrate. At that time, the TFT substrate and the counter substrate are overlapped with a gap of 2 to 3 μm, and are fixed to each other with a sealing material, and moreover, a spacer hits and supports each pixel to maintain sufficient strength, and the panel is peeled off. There is nothing to do.

FIG. 17 is a schematic view showing a polishing process using the powder particle spraying process. As shown in the figure, a constant amount of a phase flow in which powder particles made of an abrasive such as silicon carbide, boron carbide or diamond are dispersed in high pressure air is jetted from a jet port on the tip side of the slit-shaped nozzle 30, and a TFT substrate is produced. Back of 1
It is reciprocally scanned along b and is polished. At this time, rough polishing, intermediate polishing, and final polishing are performed in this order, and the particle size of the abrasive is reduced accordingly to increase the surface accuracy. When the amount of processing is large, the workpiece is polished to a thickness close to the target by rough polishing, and then medium polishing and final polishing are performed. For example, if the TFT substrate 1 has a thickness of 800 μm, it is ground to 500 μm by rough polishing,
Shaving 700μm with medium polishing and 750μ with final finishing polishing
After polishing, 50 μm is left.

50 μm finish of powder particle injection processing on TFT substrate
Since the target of the thickness of the TFT substrate is 20 ± 3 μm, the buff optical polishing shown in FIG. 16 can be used for the final polishing. This optical polishing is performed for each polishing amount of 10 μm while confirming the remaining thickness by an optical or laser type step depth measuring device with reference to an alignment mark on the surface of the TFT substrate.

FIG. 18 shows a step of adhering the microlens substrate 4 to the back surface of the TFT thin substrate 1 after the polishing step shown in FIG. As shown in the figure, with the base glass 2, the counter substrate 17 with a built-in ML, and the thin TFT substrate 1 integrated, the rear surface of the thin TFT substrate 1 is exposed to ultraviolet irradiation curing or ultraviolet irradiation + thermosetting sealing material 6. Is dispensed to form a frame, the microlens substrate 4 is superposed at a predetermined gap with reference to the alignment mark, and ultraviolet rays are irradiated to cure the sealing material 6. At this time, the focal length of the microlens is finely adjusted by the thickness of the sealing material 6,
A spacer of a predetermined size (made of metal, glass, ceramics or other material, used alone or mixed at an appropriate ratio, preferably spherical or fiber-like) is mixed in the sealing material 6 within a range not deteriorating the sealing property. If so, fine adjustment may be easy.

Thereafter, as shown in FIG. 19, the frame-shaped sealing material 6
The high-refractive-index transparent optical resin 5 is injected from the injection port provided in the above by vacuum and pressure, and the injection port is sealed with an ultraviolet irradiation curable adhesive. After that, although not shown, the cyanoacrylate adhesive 3 is heated to melt the base glass 2 and the entire panel is washed with an organic solvent such as IPA, acetone, acetone + ethanol, or methanol. In the case of a hot-melt water-soluble wax, the base glass 2 is peeled off by heating, and the entire panel is ultrasonically cleaned with pure water or warm pure water at 50 to 60 ° C.

FIG. 20 (a) shows an example in which the jig 2a is used instead of the base glass for holding the panel. The jig 2a which also serves as a base glass is fixed to a work holder 29 of the polishing plate. A passage 2b for vacuum suction is formed in the jig 2a and the holder 29. The panel in which the TFT substrate 1 and the counter substrate 17 with a built-in microlens are assembled is polished while being fixed to the jig 2a by vacuum suction. At this time, it is desirable to prevent the electrostatic damage during polishing by short-circuiting the external connection terminals 1t of the TFT substrate 1 with the conductive pads 2p provided on the jig 2a. In the examples shown in (b) and (c) of FIG. 20, the LCD panel is fixed to the work holder 29 of the large polishing board provided with a plurality of jigs 2a also serving as base glasses. With the TFT substrate 1 side facing upward, the ML counter substrate 17 side is set in the recess of the jig 2a and fixed by vacuum suction, and the back surface of the TFT substrate is polished on one side.
Also at this time, it is desirable to prevent the electrostatic damage during polishing by short-circuiting the external connection terminals of the TFT substrate with the conductive pads provided on the jig 2a. TFTs commonly used in high temperature polysilicon TFT LCDs for projectors
The synthetic quartz glass of the substrate and the counter substrate has high precision surface and dimensional finishing specifications. Therefore, FIGS.
In each of the examples shown in (1) and (2), it is possible to substitute the base glass for the counter substrate by sufficiently checking the film thickness during the polishing work, and the base glass may be eliminated to reduce the cost. .

FIG. 21 is a schematic sectional view showing another example of the liquid crystal display element manufactured according to the present invention. Opposed substrate 17 with built-in microlens and TFT with built-in microlens
The substrate 7 is superposed and fixed with a sealant 8 at a predetermined gap, and a liquid crystal 9 is held between the two. Here, in the microlens array integrated with the back surface of the TFT substrate 1 thinned by polishing, the lens surface r has a double structure. That is, the same refractive index as the convex lens surface formed on the transparent resin layer 4 having a refractive index ng1-2 is n.
The convex lens surface formed on the transparent resin layer 4 ′ of g2-2 is
The transparent optical resin 5 having a refractive index n1 is sealed between them by a sealing material 6 to form a microlens. At this time, the refractive index n of the transparent optical resin 5
1 is the refractive index ng1-2, ng2 of the transparent resin layers 4, 4 '.
Lower than -2. The counter substrate 17 side with a built-in microlens has the same structure, and a transparent optical resin having a refractive index of n1 is provided between the transparent resin layer having a refractive index of ng1-1 and the transparent resin layer having a refractive index of ng2-1. 15 is inserted.

FIG. 22 shows a specific example of the shape and dimensions of the liquid crystal display device manufactured according to the present invention. MLT
The FT substrate 7 and the ML counter substrate 17 are superposed and fixed to each other with a predetermined gap, and the liquid crystal 9 is held between them. The focal length of the microlenses on the ML counter substrate 17 side is F1 = 30.69 μm in air. The microlens has a structure in which a transparent resin layer having a refractive index of 1.45 and a transparent optical resin 15 having a refractive index of 1.66 are in contact with each other with the lens surface 14r as a boundary. The counter substrate 11 is made of neoceram glass having a refractive index of 1.54 and is thinned by polishing. The depth of the lens surface 14r is 10.3 μm, and the thickness of the counter substrate 11 is reduced to 20 μm. On the other hand, the focal length of the microlens formed on the MLTFT substrate 7 is F2 = 41.4 μm (actual size 6
4.6 μm). A transparent resin layer having a refractive index of 1.44 and a transparent optical resin 5 having a refractive index of 1.596 are in contact with each other with the lens surface 4r as a boundary to form a microlens. The quartz substrate 1 having a refractive index of 1.46 is thinned to 20 μm. In this way, the distance between the principal points between the condenser lens formed on the ML counter substrate 17 side and the field lens formed on the MLTFT substrate 7 side is 64.6 μm. The TFT pixel pitch is 18 μm. The above dimensions are all actual values except the focal length.

FIG. 23 is a schematic diagram showing optical characteristics of a liquid crystal display device having a dual microlens structure manufactured according to the present invention. The lens surface for condensing is arranged on the counter substrate side, and the lens surface having a field function is formed by TF.
It is arranged on the T substrate side. The liquid crystal panel according to this example includes the TFT substrate 50B and the TFT substrate 50.
It is provided with a counter substrate 50A which is arranged to face the light incident surface of B with a liquid crystal layer 45 in between.

The counter substrate 50A is arranged in order from the light incident side.
Glass substrate 41, transparent resin layer 43A, first microlens array 42A, and thinned counter substrate 44A
And have. On the other hand, the TFT substrate 50B has a pixel electrode 46 and a black matrix 47 in order from the light incident side.
And a thinned TFT substrate 44B, a second microlens array 42B, a transparent resin layer 43B, and a glass substrate 48.

The first microlens array 42A is made of a transparent optical resin, and a plurality of first microlenses 42M are provided two-dimensionally corresponding to each pixel electrode 46.
-1. Each microlens 42M-1 has a first lens surface R1 of positive power and functions as a lens for focusing light. In this example, the transparent resin layer 43A has a refractive index n1 and the first microlens array 42A has a refractive index n2.
Satisfy the relationship of n2> n1, and the first lens surface R1
However, it has a convex shape on the light incident side (light source side).

Similarly to the first microlens array 42A, the second microlens array 42B is also made of a transparent optical resin and is provided with a plurality of second two-dimensionally corresponding to each pixel electrode 46. It has a micro lens 42M-2. Each micro lens 42M-2 has a second lens surface R2 of positive power and functions as a field lens. That is, the focal position of the second lens surface R2 is substantially coincident with the principal point position of the first lens surface R1 (first microlens 42M-1) (dotted line optical path). In this example, the refractive index n of the transparent resin layer 43B is
4 is larger than the refractive index n3 of the second microlens array 42B, and the second lens surface R2 has a convex shape on the light emission side.

In this example, the pixel aperture is located between the two microlenses 42M-1 and 42M-2 (two lens surfaces R1,
It has a dual microlens structure located between (R2). Two microlenses 42M- on the optical axis 60
The combined focal position of 1,42M-2 is located near the pixel aperture (solid line optical path). The position of the combined focus position and the pixel aperture is adjusted by, for example, the microlens 42M-1,
It can be controlled by adjusting the thickness between 42M-2 and the pixel aperture. Although this structure has the highest effective aperture ratio, it has been considered that the difficulty of the conventional workability is the highest.
The present invention overcomes this difficulty of workability and realizes the illustrated dual microlens structure.

[0053]

As described above, according to the present invention, a liquid crystal display device having a dual microlens structure in which microlenses are built in both the counter substrate and the TFT substrate can be realized. As a result, it is possible to improve the effective aperture ratio and the utilization efficiency of the light from the light source, and it is possible to achieve high brightness. Further, when applied to a projection type display device, downsizing of a set, cost reduction of a projection lens and the like are possible. or,
By chamfering by V-cut dicing and then adopting full-cut dicing, it is possible to prevent cracks and cracks in the TFT substrate, improving yield and quality. Since it is possible to prevent static electricity damage and cracks in the thin TFT substrate during single-sided optical processing, the yield and quality are improved.

[Brief description of drawings]

FIG. 1 is a process drawing showing a method for manufacturing a liquid crystal display element according to the present invention.

FIG. 2 is a process drawing showing an embodiment of a method for manufacturing a liquid crystal display element according to the present invention.

FIG. 3 is a schematic diagram showing a dividing step.

FIG. 4 is a process drawing showing another embodiment.

FIG. 5 is a schematic view showing an assembly process.

FIG. 6 is a schematic view showing a method of manufacturing a counter substrate with a built-in microlens.

FIG. 7 is a process drawing showing another embodiment.

FIG. 8 is a process drawing showing another embodiment.

FIG. 9 is a process drawing showing yet another embodiment.

FIG. 10 is a process drawing showing yet another embodiment.

FIG. 11 is a process drawing showing yet another embodiment.

FIG. 12 is a process drawing showing yet another embodiment.

FIG. 13 is a schematic view showing another embodiment.

FIG. 14 is a schematic diagram showing a panel against static electricity.

FIG. 15 is a schematic view showing a panel against static electricity.

FIG. 16 is a schematic view showing a polishing step.

FIG. 17 is a schematic view showing a polishing step.

FIG. 18 is a cross-sectional view showing a bonding step using an optical resin.

FIG. 19 is a plan view showing a bonding step using an optical resin.

FIG. 20 is a schematic cross-sectional view showing another example of the polishing step.

FIG. 21 is a cross-sectional view showing an example of a liquid crystal display element manufactured according to the present invention.

FIG. 22 is a schematic view showing an example of a liquid crystal display element manufactured according to the present invention.

FIG. 23 is a schematic partial cross-sectional view showing an optical function of a liquid crystal display element manufactured according to the present invention.

FIG. 24 is a schematic diagram showing an example of a projection display device.

25 is a schematic perspective view showing an example of a liquid crystal display element incorporated in the projection display device shown in FIG.

[Explanation of symbols]

1 ... TFT substrate, 2 ... Stand glass, 3 ... Adhesive, 4 ... Microlens substrate, 5 ... Optical resin,
6 ... Sealing material, 8 ... Sealing material, 9 ... Liquid crystal,
11 ... Counter substrate

Continued front page    F-term (reference) 2H090 JA02 JA04 JA19 JB02 JB11                       JB12 JC01 JD01 LA04 LA12                       LA16                 2H091 FA29X FA29Z FB03 FB07                       FC15 FC18 FC22 FC24 FC25                       FD06 FD15 FD22 GA01 GA13                       GA17 LA11 LA16 MA07                 2H092 JA24 NA07 PA01 PA07 RA05

Claims (17)

[Claims] 1. A substrate having at least a pixel electrode and a front surface on which a switching element for driving the pixel electrode is formed and a back surface on the opposite side thereof, and a surface on which at least a counter electrode is formed and a back surface on the opposite side thereof. And a liquid crystal layer disposed between the substrates, in which the pixel electrode and the counter electrode are joined to face each other with a predetermined gap therebetween, and one of the substrates has a panel structure. A microlens array, in which microlenses for collecting light are two-dimensionally arranged, is integrally formed on each pixel electrode, and the other substrate has two microlenses through which the light condensed for each pixel electrode passes. In a method of manufacturing a liquid crystal display element in which a microlens array arranged in a dimension is integrally formed, an adhering step of adhering a base plate to a front surface of the substrate, and a back surface of the substrate held on the base plate. Polish And a polishing step of reducing the wall thickness, a bonding step of bonding a microlens array to the polished back surface via a transparent optical resin having a higher or lower refractive index than the substrate, and a front surface of the substrate. A method of manufacturing a liquid crystal display element, characterized in that a microlens array is integrated with the back surface of the substrate by a peeling step of peeling and cleaning the base plate. 2. A plurality of microlens arrays are attached to the surface substrate by subjecting the surface substrate having an area corresponding to a plurality of panels in advance to the adhering step, the polishing step, the laminating step and the peeling step. 2. The method of manufacturing a liquid crystal display device according to claim 1, wherein after the integration, a dividing step of cutting into a single substrate corresponding to each panel is performed at an appropriate stage. 3. After forming a plurality of microlens arrays on one surface substrate, the dividing step is immediately performed to separate the microlens arrays into one single substrate corresponding to each panel, and the microlens array is previously integrated. 3. The method for manufacturing a liquid crystal display device according to claim 2, wherein the panel is assembled and fixed to the other single substrate one-to-one with a predetermined gap. 4. A plurality of microlens arrays are formed on one surface substrate, and then the other single substrate in which the microlens arrays are previously integrated is individually assembled to the surface substrate, and then the dividing step is performed. 3. The method for manufacturing a liquid crystal display device according to claim 2, wherein the liquid crystal display device is separated into individual panels after being completed. 5. One surface substrate having a plurality of microlens arrays integrated therein and the other surface substrate having a plurality of microlens arrays integrated together are superposed and fixed at a predetermined gap. The method for manufacturing a liquid crystal display device according to claim 2, wherein after assembling the panels for the individual pieces, the dividing step is performed to separate the individual panels. 6. In the dividing step, a first dicing is performed along a boundary that divides the surface substrate into individual panels to form a groove having a V-shaped cross section, and further a second dicing is performed to form the groove. 3. The method for manufacturing a liquid crystal display device according to claim 2, wherein the single substrate is completely cut and the end face is tapered. 7. A liquid crystal layer in a temperature range that does not impair the heat resistance of the microlens array previously integrated with the exposed surface of the substrate after the base plate is peeled and washed from the surface of the substrate in the peeling step. The method for manufacturing a liquid crystal display element according to claim 1, further comprising an alignment step of forming an alignment layer for aligning the liquid crystal. 8. An alignment for aligning a liquid crystal layer in advance with respect to the front surface of the substrate before the microlens array is integrated on the back surface of the substrate by performing the adhering step, the polishing step, the laminating step and the peeling step. The method for manufacturing a liquid crystal display device according to claim 1, wherein an alignment step of forming a layer is performed. 9. The method of manufacturing a liquid crystal display device according to claim 1, wherein the polishing step is performed by buffing optical polishing, powder injection, chemical mechanical polishing, and chemical etching alone or in combination. . 10. The polishing step polishes the back surface of the substrate so that the focal point of the microlens functioning as a field lens when assembled into a panel is substantially coincident with the principal point of the microlens functioning as a condenser lens. The method for manufacturing a liquid crystal display element according to claim 1, wherein the thickness is reduced by cutting. 11. The laminating step comprises a step of processing an optical glass material having a relatively low refractive index to form a microlens array in which each microlens surface is two-dimensionally arranged, and a step of forming the polished substrate. The step of aligning the back surface and the microlens array and superposing them at a predetermined gap, and filling and curing a transparent optical resin having a refractive index higher or lower than that of the substrate between them, and curing the same. A method for producing the liquid crystal display element described. 12. The bonding step forms a closed gap having a predetermined gap by fixing the back surface of the polished substrate and the microlens array with a sealing material, and forming a gap having a higher refractive index than that of the substrate. The method for manufacturing a liquid crystal display device according to claim 11, wherein a transparent optical resin having a low refractive index is filled and sealed. 13. The method of manufacturing a liquid crystal display element according to claim 11, wherein the microlens surface is processed into a spherical surface, an aspherical surface or a Fresnel surface. 14. The method of manufacturing a liquid crystal display device according to claim 1, further comprising a cleaning step of cleaning a base plate which has been used and has been peeled off by the peeling step and reused it. 15. A pre-process for integrating a microlens array on a first substrate on which a counter electrode is previously formed,
An assembling step of assembling a panel by forming a first substrate on which the microlens array is integrated on the surface of a second substrate on which pixel electrodes and switching elements for driving the pixel electrodes are formed in advance; A base plate is adhered to the front surface side of the second substrate via the first substrate, and the polishing step polishes the back surface of the second substrate in a state where the base plate is held together with the panel, 2. The method of manufacturing a liquid crystal display device according to claim 1, wherein in the bonding step, a microlens array is bonded to the back surface of the polished second substrate. 16. The polishing step comprises polishing the back surface of the second substrate with a plurality of external connection terminals formed on the second substrate held at the same potential. The method for manufacturing a liquid crystal display element according to claim 15. 17. The method of manufacturing a liquid crystal display device according to claim 15, wherein in the bonding step, the first substrate side of the panel is attached to a base plate fixed to a polishing plate used in the polishing step in advance. .