JP2003035898A - Plane display element and manufacturing method for plane display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve manufacturing yield by preventing a light diffusion layer or substrate from damaging owing to a shock when a plane display element which has the light diffusion layer on an internal surface of a couple of substrates is cut to prescribed size, and to obtain excellent display quality for a long time by increasing the adhesive strength of a sealant of a plane display cell and holding the durability of the sealant. SOLUTION: The light diffusion layer 28 in an area of ±1 mm from a cutting line 38 when a liquid crystal display element 10 is cut to the prescribed size after the light diffusion layer 28 is formed on the entire surface of a large-sized glass plate 37 is ground and removed and then the light diffusion layer 28 has its end surface positioned 1 mm inside the end surface of a glass substrate 27 of an opposite substrate 13. The sealant 16 is arranged on the area of the light diffusion layer 28 and large-sized glass plates 36 and 37 are stuck together and cut along the cutting line 38 to obtain a liquid crystal display cell.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat display element, and more particularly to a flat display element having a light diffusion layer on the inner surface of a substrate and a method for manufacturing the flat display element.

[0002]

2. Description of the Related Art In recent years, a light modulating layer such as a liquid crystal is provided in a gap surrounded by a sealant of a flat display cell which is used for a personal computer terminal, a monitor and the like and has a pair of substrates having transparent electrodes arranged to face each other. As a flat display device element provided,
There has been a demand for a device having a wide viewing angle without impairing the display quality. Therefore, conventionally, by providing a light diffusion layer on the inner surface of the liquid crystal display element, as disclosed in Japanese Patent Laid-Open No. 9-297295, etc.,
A flat panel display device has been proposed which prevents display defects such as bleeding without impairing the viewing angle.

For example, as shown in FIG. 6, a liquid crystal display element 1 for maintaining a viewing angle and obtaining a good display includes a counter substrate 2 in which a light diffusion layer 2b and a counter electrode 2c are laminated on an inner surface of a glass substrate 2a. On the glass substrate 3a, a thin film transistor (hereinafter abbreviated as TFT) 3b, a color filter layer 3c, a pixel electrode 3d, a black mask (hereinafter abbreviated as BM).
An array substrate 3 having 3e is disposed so as to face it, and a liquid crystal layer 6 is enclosed in a region surrounded by a sealant 4.

[0004]

However, in the above-mentioned conventional liquid crystal display element 1, the light diffusion layer 2b is formed on the entire surface of the glass substrate 2a of the counter substrate 2. Therefore, when manufacturing a liquid crystal cell, for example, a process of bonding a plurality of substrates in a large plate state in which a plurality of substrate patterns are formed on a large glass plate, and then cutting each substrate into a prescribed size to obtain a liquid crystal cell. In the above, in the light diffusion layer 2b of the cutting portion, due to the impact when the liquid crystal cells of the plurality of surfaces are individually cut out,
There is a risk of damage such as floating from the glass substrate 2a due to cracking, chipping, or peeling, and cracking, chipping, or scraping of the cut glass substrate 2a.

The glass substrate 2a and the light diffusion layer 2b are damaged because the light diffusion layer 2b is made of a non-planar (uneven) film at the cut portion of the glass substrate 2a. Since the materials such as the light diffusion layer 2b having different hardness are laminated, the shaving by cutting should originally proceed in the thickness direction of the glass substrate 2a, but the force is not evenly applied and the shaving in other directions is not performed. It is thought to be caused by the phenomenon of dispersion and progress. The damage of the glass substrate 2a and the light diffusion layer 2b may deteriorate the display quality of the liquid crystal display element 1 and render it unusable.

Therefore, the present invention is to eliminate the above-mentioned problems, and in the case of forming a light diffusion layer on the inner surface of a flat display cell, the light diffusion layer or the light diffusion layer caused by the cutting operation of the flat display cell at the time of manufacturing the flat display cell An object of the present invention is to provide a flat panel display element and a method for manufacturing the flat panel display element, which can prevent the substrate from being damaged and can obtain a flat panel display element having excellent display quality with a high manufacturing yield.

[0007]

Means for Solving the Problems The present invention is, as a means for solving the above problems, attached to an inner surface of one of a pair of substrates and the pair of substrates, and an end surface of the substrate is inside the end surface of the substrate. A light diffusing layer, a sealant disposed on the light diffusing layer so as to surround the display regions of the pair of substrates, and a space enclosed by the sealant between the pair of substrates. And a light modulation layer.

Further, according to the present invention, as a means for solving the above problems, a pair of large-sized substrates are cut into a predetermined size to attach a light diffusion layer to the inner surface of one of the substrates and surrounded by a sealant. In the method for manufacturing a flat display element in which a light modulation layer is enclosed in a gap, a step of forming a light diffusion layer having an end surface inside the end surface of the large substrate on the large substrate That is, the step of disposing the sealant in a region corresponding to the formation region of the light diffusion layer, the step of bonding the pair of large-sized substrates with the sealant, and the pair of bonded large-sized substrates Is cut into the predetermined size.

As a means for solving the above problems, the present invention cuts a pair of large-sized substrates into a predetermined size so that the light diffusion layer is attached to the inner surface of one of the substrates and surrounded by a sealant. In a method of manufacturing a flat display element, wherein a plurality of flat display elements are formed by enclosing a light modulation layer in the gap, a step of forming a plurality of light diffusion layers on the large-sized substrate with a predetermined gap, Any one of a pair of large-sized substrates, the step of disposing the sealing agent in a region corresponding to the formation region of the light diffusion layer of the plurality of surfaces,
The step of bonding the pair of large-sized substrates with the sealing agent and the step of separating the bonded pair of large-sized substrates in the region of the predetermined gap are performed.

With the above structure, the present invention makes it possible to manufacture a flat display element having a good display quality at a high manufacturing yield without damaging the substrate or the light diffusion layer when cutting out the flat display cell during manufacturing. It is intended to put the flat display device to practical use.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 is a schematic configuration diagram showing a liquid crystal display element 10 having a diagonal size of 10 inches and a pixel number of SVGA and a backlight 11 for illuminating the liquid crystal display element 10, which is a flat display element.

In the liquid crystal display element 10, a pair of substrates, an array substrate 12 and a counter substrate 13 are arranged to face each other with a spacer 14 interposed therebetween, and a liquid crystal as a light modulation layer is formed in a gap formed by bonding the periphery with a sealant 16. The layer 17 is enclosed, and polarizing plates 12a and 13a are attached to the outer surfaces of the array substrate 12 and the counter substrate 13.

The array substrate 12 has a T for driving a liquid crystal near the intersection of a scanning line and a signal line (not shown) on the glass substrate 18.
It has an FT element 20. R on the TFT element 20
A color filter layer 21 in which (red), G (green), and B (blue) colored layers are arranged in stripes is arranged. Reference numeral 22 is a BM that masks the periphery of the display area.

A plurality of pixel electrodes 23 made of indium tin oxide (hereinafter referred to as ITO) are formed in a matrix pattern on the color filter layer 21 in a region surrounded by scanning lines and signal lines (not shown). However, the pixel electrode 23 is connected to the source electrode (not shown) of the TFT element 20 through the through hole 24 formed in the color filter layer 21, and is driven by the TFT element 20. Further, the columnar spacer 14 is formed on the pixel electrode 23, and the liquid crystal alignment film 22 is formed thereon.

On the other hand, the counter substrate 13 has a light diffusion layer 28 on a glass substrate 27, a counter electrode 30 is formed on the light diffusion layer 28, and a liquid crystal alignment film 31 is further formed on the counter electrode 30.
Is deposited. The light diffusing layer 28 is formed by stacking three layers in which transparent and uniform plastic spheres 28b having a particle diameter of 5 μm are horizontally and evenly arranged in a transparent silicone resin 28a, and the end surface of the light diffusing layer 28 is located 1 mm inside the end surface of the glass substrate 27. It is formed to be located. The sealant 16 has a width of about 1 mm on the light diffusion layer 28 and is arranged so as to surround the display region, which is a region where the plurality of pixel electrodes 23 are formed. Sealing agent 16
Is bonded to the surface of the light diffusing layer 28, the height is about 5 μm, which is approximate to the sum of the height of the columnar spacer 14 and the thickness of the color filter layer 21.

Next, a method of manufacturing the liquid crystal display element 10 will be described. In the present embodiment, as shown in FIG. 2, four arrays of the array substrate 12 and the counter substrate 13 are formed on the large glass plates 36 and 37, which are a pair of large substrates, respectively.
After laminating a pair of large glass plates 36, 37 and cutting,
The liquid crystal cells having the same four surfaces are formed.

First, the array substrate 12 is a large glass plate 36.
The TFT element 20 is formed by repeating patterning by a normal photolithography process on each of the upper four surfaces. Next, R (red), G (green), and B (blue) colored layer materials are sequentially patterned in a stripe shape to form a color filter layer 21, and further a BM 22 is formed around the display area, followed by sputtering. Then, an ITO film is formed, a pattern is formed by a photolithography process, and pixel electrodes 23 arranged in a matrix on the color filter layer 21 are formed.
The liquid crystal alignment film 26 is applied, and the spacers 14 are further patterned to form four array substrates 12 on the large glass plate 36.

On the other hand, the counter substrate 13 has a light diffusion layer 28 formed on each of four surfaces on a large glass plate 37 which is a large substrate as follows. TFC7, which is a transparent silicone resin that is optically isotropic on a large glass plate 37
700 (Toshiba Silicone, refractive index = 1.4) 28a
Is applied to a thickness of 0.1 mm, and is irradiated with an amount of ultraviolet rays that solidifies the surface of the silicone resin 28a to such an extent that the surface exhibits tackiness. An optically isotropic and transparent plastic sphere having a particle diameter of 5 μm (for example, Micropearl (trade name) manufactured by Sekisui Fine Chemical Co., Ltd., refractive index = 1.57) on the surface of the adhesive silicone film 28a. ) 28b is evenly applied by rubbing. Next, the surface coated with the plastic balls 28b is washed with water and then dried. The process of coating the above-mentioned silicone resin 28a again, solidifying and then coating the plastic sphere 28b, and washing with water is repeated three times, and finally the silicone resin 28a is coated on the plastic sphere 28b on the outermost surface and UV rays are applied. To sufficiently harden the silicone resin to form the light diffusion layer 28 on the entire surface of the large glass plate 37.

Next, as shown in FIG. 2, the cut-out size of the counter substrate 13, that is, the cutting line 38 of the large glass plate 37.
The light diffusion layer 28 in the region of ± 1 mm from is removed by polishing. Further, an ITO film is formed on the light diffusion layer 28 by a sputtering method, a counter electrode 30 is patterned, and then a liquid crystal alignment film 31 is applied thereon, and four counter substrates 13 are formed on a large glass plate 37. To do.

After that, the liquid crystal alignment films 26 and 31 are each subjected to an alignment treatment by rubbing, and on each array substrate 12 on the large glass plate 36 and in the light diffusion layer 28 forming region on the large glass plate 37. A transfer for applying XN-21S manufactured by Mitsui Chemicals Co., Ltd. as a sealant 16 so as to have a finished seal width of 1.0 mm and applying a voltage from the array substrate 12 to the counter electrode 30 at a position facing each other. Apply an agent (not shown). Furthermore, the liquid crystal alignment film 2
Both large glass plates 36 and 37 are arranged so as to face each other so that the rubbing directions of 6 and 31 are 90 °, respectively.
Heat cure and bond.

Next, a cutting process for cutting the pair of large glass plates 36, 37 bonded together by a cutting line 38 is carried out,
The same four-sided liquid crystal cell is formed. When this liquid crystal cell is cut out, the light diffusion layer 28 is removed in the region of ± 1 mm with the cutting line 38 as the center, so the light diffusion layer 2
No. 8 does not receive the impact during cutting. Therefore, the light diffusion layer 28 is
There is no damage due to impact during cutting, and the cut surface of the glass substrate 27 having the light diffusion layer 28 is not damaged, so that the cutting process is performed with a high manufacturing yield.

After that, the liquid crystal composition is sealed in the spaces between the liquid crystal cells to form the liquid crystal layer 17, and then the polarizing plates 12a and 13a are attached to the array substrate 12 and the counter substrate 13, respectively, to complete the liquid crystal display element 10. To do.

The liquid crystal display device 10 manufactured in this way
When the cutting quality was evaluated, no cracks, chips or shavings were observed on the light diffusion layer 28 and further on the glass substrate 27. In addition, the glass substrate 27 due to peeling of the light diffusion layer 28
No floats were observed. Further, the obtained liquid crystal display element 10 was subjected to 100
A 0-hour continuous image display test was performed and the display quality was evaluated. As a result, there was no display unevenness and no display failure due to peeling of the sealant 16 or the like, and a good display image was obtained.

On the other hand, as (Comparative Example 1), the light diffusing layer 28 in the region of the cutting line 38 on the large glass plate 37 was not removed, but the light diffusing layer 28 was formed on the entire surface of the large glass plate 37 as a pair. A liquid crystal display element 41 shown in FIG. 3 is manufactured in exactly the same manner as this embodiment, except that the large glass plates 36 and 37 are bonded together with the sealant 16 and the liquid crystal cells on four sides are cut out along the cutting line 38. did.

When the cutting quality of the liquid crystal display element 41 of this (Comparative Example 1) was evaluated, cracking, chipping or scraping was observed in the light diffusion layer 28 and the glass substrate 27. In addition, floating from the glass substrate 27 due to peeling of the light diffusion layer 28 was also observed. Further, the liquid crystal display element 41 of this (Comparative Example 1)
As in this embodiment, high temperature and high humidity (50 ° C, 80%)
A continuous image display test was performed under the conditions and the display quality was evaluated. After 380 hours, the light diffusion layer 28 penetrated from the outside of the liquid crystal display element 41 through the floating portion from the glass substrate due to cracking, chipping, shaving, or peeling. Display unevenness, which is considered to be caused by the water content, was generated, and the display quality was significantly deteriorated.

Next, as (Comparative Example 2), a large glass plate 3
7 except that the removal range of the light diffusion layer 28 on 7 is set to the position where the end surface of the light diffusion layer 28 corresponds to the center of the sealant 43 when the pair of large glass plates 36 and 37 are bonded together. Liquid crystal display element 43 shown in FIG.
Was produced.

Further (Comparative Example 3), a large glass plate 3
7 except that the end surface of the light diffusion layer 28 is located inside the inner peripheral surface of the sealant 47 when the pair of large glass plates 36 and 37 are bonded to each other. A liquid crystal display element 48 shown in FIG. 5 similar to that of the present embodiment.
Was produced.

When the cut quality of the liquid crystal display elements 44 and 48 of (Comparative Example 2) and (Comparative Example 3) was evaluated, it was found that the light diffusing layer 28 and the glass substrate 27 were not cracked, chipped or scraped. Not observed. In addition, the light diffusion layer 28
No detachment from the glass substrate 27 due to peeling was also observed.

However, in the liquid crystal display elements 44 and 48 of (Comparative Example 2) and (Comparative Example 3), the sealing agents 43 and 47 are used.
The decrease in the adhesiveness was observed. Therefore, the sealant 4 of the liquid crystal display elements 44 and 48 of (Comparative Example 2) and (Comparative Example 3) is used.
Table 1 shows the result of comparing the finished seal width and the adhesive strength of the seal portion with that of the present embodiment as the performance of the seals 3 and 47. The seal width is for each liquid crystal display element 1
The seal width on four sides of 0, 44, and 48 was measured at 25 points / total of 100 points, and the average value and three times the standard deviation (average ±
3σ) was used for comparison and evaluation. As a result, the standard deviation of 3
Double (average ± 3σ) is ± 0.14 in this embodiment.
In comparison with Comparative Example 2, ± 0.22 mm,
In (Comparative Example 3), it was as large as ± 0.32 mm, and the seal width in (Comparative Example 2) or (Comparative Example 3) was nonuniform as compared with the present embodiment.

The adhesive strength of the seal portion is the same as that of each liquid crystal display element 1.
A pair of glass substrates 18 and 27 forming 0, 44 and 48
Were drawn to each other in the direction perpendicular to the glass surface, and comparative evaluation was made by the tensile load at the time when the two glass substrates 18 and 27 were peeled off. As a result, the seal width of the present embodiment is as narrow as 1.02 ± 0.14 mm, whereas in Comparative Example 2 the seal width is 1.16 ± 0.22 mm, which is wide over the entire surface. Also, in (Comparative Example 3), the seal width is not so wide as compared with the seal width of the present embodiment, but it is non-uniform at 1.04 ± 0.32 mm and is partially wide. The cohesive failure was apt to occur in a wide area of, and the strength was reduced.

[Table 1] As a result, in the liquid crystal display elements 44 and 48 of (Comparative Example 2) and (Comparative Example 3), the manufacturing yields at the time of cutting the large glass plates 36 and 37 are the same as those of the present embodiment.
It was found that the adhesive strength of the sealing agents 43 and 47 was inferior to that of the present embodiment.

With the above structure, in the present embodiment, the light diffusion layer 2 for expanding the viewing angle and improving the image quality.
A liquid crystal cell having a pair of large glass plates 36, 37
When cutting out after producing four sides at the same time using
Since the light diffusing layer 28 is removed in the region, the light diffusing layer 28 is not cracked, chipped, scraped, or peeled off from the glass substrate 27 due to the impact during cutting, and the glass substrate 27 is removed. The production yield can be improved without cracking, chipping or chipping of No. 27. Further, the finished sealing agent 16 is excellent in uniformizing the sealing width, can prevent the cohesive failure caused by the partial increase in the sealing width, can obtain good adhesive strength over the entire surface of the sealant, and is high without causing a sealing failure. The durability was maintained and good display quality was obtained for a long time.

The present invention is not limited to the above-described embodiment, and changes can be made without departing from the spirit of the present invention. For example, the distance from the end face of the substrate to the end face of the light diffusion layer is the same as that of the above-mentioned embodiment. The shape is not limited to 1.02 mm,
Considering the manufacturing precision of the array substrate and counter substrate on a large substrate, the bonding precision of a pair of large substrates, the removal precision of the light diffusion layer in the separation region of the large substrates, and the precision of the separation of a pair of large substrates. The distance may be such that the light diffusion layer is not likely to remain on the cutting line when the large substrate is cut off.

In the above-described embodiment, a cutting test was conducted by changing the removal area of the light diffusion layer 28 with the cutting line 38 as the center.
When the light diffusion layer 28 in the area of 3 mm is removed, the cutting quality deteriorates because the actual cutting line at the time of cutting out the liquid crystal cell is applied to the area where the light diffusion layer 28 is not completely removed due to an error in manufacturing accuracy. Then, a lot of scraping occurred. On the other hand, when the light diffusion layer 28 in the region of ± 0.5 mm is removed with the cutting line 38 as the center, good cutting quality can be obtained, and the sealing width and peel strength are both excellent. Is approximately the same as the area of ± 1.0 mm centering on the cutting line 38, and high temperature and high humidity (50 ° C, 80%)
Even in the 1000-hour continuous image display test under the conditions, good display quality was obtained without any display defects. From the above, the distance from the substrate end face to the light diffusion layer end face is ±
It is more desirable to set it to about 0.5 mm to 1 mm.

Also, the method of processing the light diffusion layer so that the end surface of the light diffusion layer is formed inside the end surface of the substrate does not have to be polished as in the above-described embodiment, but is irradiated with laser light, for example. The light diffusion layer in the cutting line region may be cut off. By doing so, the positional accuracy of the end surface of the light diffusion layer to be removed can be further improved. Further, when forming the light diffusion layer, the cutting line region may be masked so that the light diffusion layer is formed in the region excluding the cutting line region.

Further, the seal width of the sealant is arbitrary within the range where there is no risk of causing cohesive failure.

The number of flat display elements formed on a large-sized substrate is not limited, and it may be a single surface. When cutting out to a prescribed flat display element size on a single surface, the light diffusion layer is
If the edge is formed so that it is inside the edge of the substrate and the sealant is placed in the light diffusion layer formation area, damage to the light diffusion layer due to impact during cutting can be prevented, and the sealing width is narrow and uniform. Can be formed into

Further, the light diffusion layer may be made of any raw material or structure. In the first embodiment, the plastic sphere 28b coated on the silicone resin 28a is not limited to three layers, but may be a single layer or Further, it may be a multilayer.
Further, the flat display element may be a reflective type or a semi-transmissive type instead of the transmissive type using a backlight.

[0038]

As described above, according to the present invention, when a flat display cell having a light diffusing layer is cut into a prescribed size, the light diffusing layer is cracked, chipped, scraped or peeled off due to an impact during cutting. It is possible to prevent damage such as floating from the substrate or damage such as cracking, chipping or shaving of the substrate, and it is possible to improve the manufacturing yield.
Further, according to the present invention, the sealing width of the sealing agent can be formed uniformly and narrow, and thus, strong adhesive strength can be obtained without causing cohesive failure of the sealing agent, and good display quality can be obtained for a long time without causing sealing failure. can get.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a liquid crystal display element and a backlight according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing cutting of a large glass plate in the embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a liquid crystal element of (Comparative example 1).

FIG. 4 is a schematic configuration diagram showing a liquid crystal element of (Comparative example 2).

FIG. 5 is a schematic configuration diagram showing a liquid crystal element of (Comparative example 3).

FIG. 6 is a schematic configuration diagram showing a conventional liquid crystal display element.

[Explanation of symbols]

10 ... Liquid crystal display element 11 ... Backlight 12 ... Array substrate 13 ... Counter substrate 14 ... Spacer 16 ... Sealant 17 ... Liquid crystal layer 18, 27 ... Glass substrate 20 ... TFT element 21 ... Color filter layer 23 ... Pixel electrode 28 ... Light diffusion layer 28a ... Silicone resin 28b ... Plastic ball 36, 37 ... Large glass plate 38 ... Cutting line

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09F 9/00 342 G09F 9/00 342Z 5C094 343 343Z 5G435 9/30 349 9/30 349Z 9/35 9 / 35 F-term (reference) 2H042 BA02 BA15 BA20 2H088 FA01 FA06 FA27 2H089 LA46 QA12 TA17 2H090 JA06 JB02 JC07 JC13 LA10 2H091 FA31Y FB02 FB13 GA01 GA09 5C094 AA31 AA42 AA43 BA43 CA24 AK12 BB02 A10A12 A12A02 A17A12 A1243

Claims (7)

[Claims] 1. A pair of substrates, a light diffusing layer attached to an inner surface of one of the pair of substrates, and an end face of which is located inside the end face of the substrate, and the pair of substrates on the light diffusing layer. 2. A flat display element, comprising: a sealant disposed so as to surround a display region of the substrate, and a light modulation layer sealed between the pair of substrates in the region surrounded by the sealant. 2. The flat display element according to claim 1, wherein the pair of substrates are made of transparent glass substrates, and an attachment surface of the light diffusion layer to the glass substrate is made of an organic material. 3. The light diffusing layer comprises a substantially spherical refracting body which is transparent in a flat transparent medium and has a refractive index different from that of the transparent medium, and which is substantially parallel to the main surface of the flat transparent medium. The flat display element according to claim 1, wherein the flat display element has evenly arranged layers. 4. The flat display element according to claim 3, wherein the transparent medium and the refracting body are optically isotropic. 5. The flat display element according to claim 1, wherein the light modulation layer is a liquid crystal layer. 6. A flat surface obtained by cutting a pair of large-sized substrates into a predetermined size so that a light diffusion layer is attached to the inner surface of one of the substrates and the light modulation layer is enclosed in a gap surrounded by a sealant. In the method for manufacturing a display element, in the large-sized substrate, a step of forming a light diffusion layer having an end surface inside the end surface of the substrate, and one of the pair of large-sized substrate, the light diffusion layer forming region The method further comprises the steps of disposing the sealant in an area corresponding to the above, bonding the pair of large-sized substrates with the sealant, and cutting out the bonded pair of large-sized substrates into the predetermined size. A method of manufacturing a flat display element, comprising: 7. A flat surface obtained by cutting a pair of large-sized substrates into a predetermined size so that a light diffusion layer is attached to the inner surface of one of the substrates and the light modulation layer is enclosed in a gap surrounded by a sealant. In the method for manufacturing a flat display element, wherein a plurality of display elements are formed, in the large-sized substrate, a step of forming a plurality of light-diffusing layers with a predetermined gap therebetween, and one of the pair of large-sized substrates, The step of disposing the sealing agent in each of the regions corresponding to the formation regions of the light diffusion layers on a plurality of surfaces, the step of bonding the pair of large-sized substrates with the sealing agent, and the pair of large-sized substrates bonded to each other And a step of separating at a region of a predetermined gap.