JP2005340182A - Method for thinning substrate of el device and method for parting laminated substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for thinning a substrate of an EL device, whereby the substrate can be easily thinned without deteriorating operability during manufacture and exerting a bad influence on an EL element part. <P>SOLUTION: A pair of glass substrates 1 of the EL device 3 are disposed so that the EL element parts 2 formed on their respective surfaces 1a face each other, and are also separately disposed so that the respective EL element parts 2 do not interfere each other by disposing a spacer member 4 between a pair of the glass substrates 1. Under this condition, the peripheral fringe part of a pair of the glass substrates 1 are pasted together through a sealing material 5, and a hollow part 6 formed between a pair of the glass substrates 1 is sealed from the outside by the sealing material 5. Then, a thinning process is applied to a pair of the glass substrates 1 by immersing a pair of the mutually integrated glass substrates 1 in etching liquid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for reducing the thickness of a substrate of an EL (electroluminescence) device.
The present invention also relates to a method of dividing a bonded substrate having peripheral portions bonded together in a state where element portions formed on the respective surfaces are opposed to each other.

  2. Description of the Related Art Conventionally, EL devices such as inorganic EL devices and organic EL devices have been widely put into practical use as displays and lighting devices for thin and light portable devices because they emit light with high brightness. This EL device has a structure in which an EL element portion having a pair of electrode layers, at least one of which is made of a transparent electrode, and a light emitting layer sandwiched therebetween is formed on a substrate.

In such an EL device, it is desired to use a thin substrate in order to reduce the thickness and weight of the entire device.
However, for example, if a thin glass substrate is used to form the EL element portion on the substrate, the operability in various processes during the production may be reduced due to the bending of the substrate, and the production may be difficult. Therefore, it is necessary to use a thick glass substrate during manufacture.

As in this EL device, in a liquid crystal display device in which a display element portion is formed on a glass substrate, since the display element portion is disposed between a pair of glass substrates, for example, as disclosed in Patent Document 1 In addition, a method has been proposed in which a liquid crystal display device is immersed in an etching solution to thin the pair of glass substrates together.
Further, as a method for cleaving a bonded substrate of a liquid crystal display device, for example, a method for cleaving a pair of bonded substrates has been proposed as disclosed in Patent Document 2.

JP-A-8-262419 JP 2004-191573 A

However, the EL device has a structure in which the EL element portion is formed on a single glass substrate, and the EL element portion is not sealed by glass but sealed by a film (film sealing) for thinning. Therefore, when the method of Patent Document 1 is applied to an EL device, the EL element portion sealed with the film may be directly immersed in the etching solution and may be damaged.
In addition, since the EL device becomes a product with one substrate, the pair of bonded substrates must be further divided into two products. However, Patent Document 2 does not describe the method of dividing.
The present invention has been made to solve such problems, and the substrate of an EL device capable of easily thinning the substrate without deteriorating the operability during manufacturing and without adversely affecting the EL element portion. An object of the present invention is to provide a thinning method.
In addition, the present invention provides a method for dividing a bonded substrate that can divide a bonded substrate having a peripheral portion bonded to each substrate in a state where the element portions formed on the surface face each other. Also aimed.

An EL device substrate thinning method according to the present invention is a method for thinning an EL device substrate having a substrate and an EL element portion formed on the substrate, wherein the EL element portion is formed on the surface thereof. The pair of substrates are arranged so that the respective EL element portions face each other, and in this state, the peripheral portions of the pair of substrates are bonded to each other so as to seal the respective EL element portions from the outside. Each is a method of thinning.
A pair of substrates are arranged so that the EL element portions formed on the respective surfaces face each other, and in this state, the peripheral portions of the pair of substrates are bonded to each other so that each EL element portion between the pair of substrates is Seal from the outside. Next, a thinning process is performed on each of the pair of substrates integrated with each other. Here, since the back surfaces of the pair of substrates (surfaces opposite to the surface on which the EL element portion is formed) are exposed to the outside, the back surface of each substrate is directly subjected to thinning processing. Each substrate is thinned.

As the thinning process, the pair of substrates can be thinned by performing etching, polishing, or blasting.
Note that the peripheral edge portions of the pair of substrates may be separated from each other with a predetermined interval so that the respective EL element portions are spaced apart from each other. In this case, the peripheral portions of the pair of substrates can be attached to each other via the sealing material. Furthermore, spacer particles for separating the peripheral portions of the pair of substrates at a predetermined interval may be included in the sealing material, or a spacer member may be interposed between the peripheral portions of the pair of substrates. As a spacer member, the double-sided tape arrange | positioned inside the sealing material can be used. Moreover, the peripheral part of a pair of board | substrate can also be bonded together through a double-sided tape.
The peripheral portions of the pair of substrates may be bonded so that the respective EL element portions are in contact with each other. In this case, it is preferable that the peripheral portions of the pair of substrates are bonded to each other via a sealing material.

After the thinning process, the pair of substrates can be separated from each other by cutting off the bonded portion of the peripheral edge of the pair of substrates. In particular, it is preferable to cut each substrate between a bonded portion of peripheral portions of a pair of substrates and each EL element portion. In addition, after the thinning process, the pair of substrates can be separated from each other by cutting each substrate at a portion corresponding to the spacer member.
The EL element portion formed on the surface of the substrate is preferably sealed with a film.
In addition, the protective film may be formed in the surface of the EL element part by which the film | membrane sealing was carried out.
A glass substrate can be used as the substrate. A substrate having a plurality of EL element portions formed on the surface thereof can also be used.

A method for dividing a bonded substrate according to the present invention is a method for dividing a bonded substrate in which peripheral portions are bonded in a state in which element portions formed on the surfaces face each other, and bonding the peripheral portions In this method, each substrate is cut in a region between the portion and the element portion and separated from each other via a hollow portion.
In addition, when each board | substrate consists of glass substrates, each board | substrate can be cut | disconnected by scribing the surface on the opposite side to the surface in which the element part was formed. At this time, it is preferable to set the height of the blade for scribing based on the substrate with the lowest thickness tolerance.

According to the present invention, a pair of substrates each having an EL element portion formed on the surface thereof are arranged so that the EL element portions face each other, and the peripheral portions of the pair of substrates are bonded to each other in that state. Since each EL element part is sealed from the outside and each pair of substrates is thinned, the substrate can be easily manufactured without deteriorating the operability during manufacturing and without adversely affecting the EL element part. Can be thinned.
Further, with respect to a bonded substrate in which the peripheral portions are bonded in a state where the element portions formed on the respective surfaces face each other, each other is provided between the bonded portion of the peripheral portions and the element portion and through the hollow portion. By cutting each substrate in the separated area, the bonded substrate can be divided into each substrate.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1
A method for thinning the substrate of the EL device according to the first embodiment of the present invention will be described with reference to the flowchart of FIG. First, in step S1, as shown in FIG. 2, an EL device 3 is formed by forming an EL (electroluminescence) element portion 2 on the surface 1a of the glass substrate 1 by a known method. The EL element portion 2 has a pair of electrode layers and a light emitting layer sandwiched between them, and the pair of electrode layers and the light emitting layer are films for preventing moisture and gas from entering from the outside. It is sealed. The EL element portion 2 is formed smaller than the size of the glass substrate 1, and the surface 1 a of the glass substrate 1 has a portion exposed around the EL element portion 2. Further, a terminal for external connection (not shown) and the like are formed on the periphery of the EL element portion 2.

  In step S2, as shown in FIG. 3, the glass substrate 1 of such a pair of EL devices 3 is arranged so that the EL element portions 2 formed on the respective surfaces 1a face each other, and a pair of glasses. For example, a spacer member 4 having a thickness of several hundred μm is disposed between the substrates 1 so that the EL element portions 2 are spaced apart from each other so as not to interfere with each other. At this time, the spacer member 4 is disposed so as to be located outside the external connection terminal of the EL element portion 2 and the like. In this state, the bonded substrate W is formed by bonding the peripheral portions of the pair of glass substrates 1 through the sealing material 5 in step S3. The hollow portion 6 formed between the pair of glass substrates 1 is sealed from the outside by a sealing material 5. The sealing material 5 is a material that does not penetrate the etching solution and is not eroded by the etching solution, and is made of a viscous resin or the like. Further, the sealing material 5 is bonded to the surface 1 a of each glass substrate 1.

Next, in step S4, the bonded substrate W is immersed in an etching solution, and the pair of glass substrates 1 are thinned. Here, since the back surfaces 1b of the pair of glass substrates 1 are exposed to the outside, the back surfaces 1b of the glass substrates 1 are directly immersed in the etching solution and etched, whereby the pair of glass substrates 1 are simultaneously thinned. can do.
At this time, since the hollow portion 6 formed between the pair of glass substrates 1 is sealed by the sealing material 5, each EL element portion 2 located in the hollow portion 6 is immersed in the etching solution. Problems such as damage are prevented.
Further, since the glass substrate 1 can be thinned after the EL element portion 2 is formed on the glass substrate 1, the EL element portion 2 can be formed on the thick glass substrate 1, whereby the EL The element part 2 can be formed efficiently without causing a decrease in operability in each process.

  After the pair of glass substrates 1 are thinned to a predetermined thickness by etching, the back surface 1b of each glass substrate 1 of the bonded substrate W is scribed to the spacer member 4 in step S5 as shown in FIG. It cut | disconnects by the corresponding part, the peripheral part of the glass substrate 1 in which the spacer member 4 and the sealing material 5 were located is cut off, and, thereby, a pair of glass substrate 1 is parted mutually. In this way, two EL devices that are reduced in thickness and weight can be obtained simultaneously.

  As the spacer member 4, a double-sided tape having a predetermined thickness, for example, a thickness of several hundred μm, that allows a gap to be formed between the EL element portions 2 facing each other can also be used. In this case, when the pair of glass substrates 1 are arranged to face each other via the spacer member 4 in step S2, these glass substrates 1 are bonded and fixed to the spacer member 4 made of double-sided tape. The workability at the time of sealing the peripheral part of a pair of glass substrate 1 with the sealing material 5 improves.

Embodiment 2
FIG. 5 shows a method for dividing the bonded substrate W in the second embodiment. In the second embodiment, after the pair of glass substrates 1 of the bonded substrate W is thinned to a predetermined thickness in the first embodiment described above, the spacer member 4 and the EL element as shown in FIG. These glass substrates 1 are cut by scribing the back surface 1b of each glass substrate 1 at a corresponding portion between the portions 2.

  That is, the area | region which mutually spaces apart between the bonding part 7 in which the spacer member 4 and the sealing material 5 of the peripheral part of a pair of glass substrate 1 are arrange | positioned, and each EL element part 2 through the hollow part 6 In addition, scribe lines SL are set as shown in FIG. 6, and the back surface 1b of each glass substrate 1 is scribed along these scribe lines SL with a scriber. Since the scribe line SL is set in a region where the pair of glass substrates 1 are opposed to each other with only the hollow portion 6 interposed therebetween, if the glass substrate 1 is cut along the four peripheral sides of the EL element portion 2 by the scribe line SL. The bonded portion 7 is separated from the EL element portion 2, and the pair of glass substrates 1 are separated from each other.

  Here, since the tolerance width of the plate thickness is doubled in the bonded substrate W in which the pair of glass substrates 1 are bonded to the thickness difference Δd of the glass substrate 1 subjected to the thinning process, Although it is possible to scribe each glass substrate 1 of the bonded substrate W by adjusting the height of the scriber blade each time, the scriber blade is based on the glass substrate 1 having the lowest thickness of the tolerance Δd. If the height is set, the glass substrate 1 can be surely scribed without being affected by the tolerance Δd. In this way, it is not necessary to adjust the height of the scriber blade every time scribe is performed, so that the efficiency of the cutting process of the bonded substrate W is improved.

Embodiment 3
FIG. 7 shows a cross-sectional structure of the bonded substrate W in the third embodiment. In this third embodiment, only the spacer member 4 made of double-sided tape is used instead of bonding the peripheral portions of the pair of glass substrates 1 through the spacer member 4 and the sealing material 5 in the first and second embodiments described above. The peripheral portions of the pair of glass substrates 1 are bonded together.
As the double-sided tape constituting the spacer member 4, it is necessary to use an acid-resistant tape so that the etching solution used when thinning the glass substrate 1 does not penetrate and is not eroded by the etching solution.

If the spacer member 4 made of such a double-sided tape is used, the peripheral portions of the pair of glass substrates 1 are held at a predetermined interval by the spacer member 4 and at the same time, the hollow portions 6 formed between the pair of glass substrates 1 are formed. By sealing from the outside, the EL element portion 2 located in the hollow portion 6 can be prevented from being immersed in the etching solution.
For example, as shown in FIG. 7, a pair of glass substrates is obtained by scribing the back surface 1b of each glass substrate 1 at a corresponding portion between the spacer member 4 and the EL element portion 2 to cut each glass substrate 1. 1 are separated from each other.

Embodiment 4
FIG. 8 shows a cross-sectional structure of the bonded substrate W in the fourth embodiment. In the fourth embodiment, only the sealing material 5 having viscosity is used instead of bonding the peripheral portions of the pair of glass substrates 1 through the spacer member 4 and the sealing material 5 in the first and second embodiments. The peripheral portions of the pair of glass substrates 1 are bonded together, and the EL element portions 2 arranged opposite to each other are in contact with each other.
Each EL element part 2 has its surface sealed with a sealing film (not shown) in order to prevent entry of moisture, gas, etc. from the outside. The peripheral portions of the pair of glass substrates 1 are bonded to each other with the sealing material 5 in a state of being in contact with each other.

Also in this case, a hollow portion 6 is formed between the bonded portion where the sealing material 5 is disposed and each EL element portion 2, and the hollow portion 6 is sealed from the outside by the sealing material 5. .
In addition, since the spacer member 4 does not exist inside the sealing material 5, sealing is performed in order to prevent the sealing material 5 disposed on the peripheral edge portions of the pair of glass substrates 1 from entering the EL element portion 2. It is desirable to adjust the viscosity of the material 5.
For example, as shown in FIG. 8, by scribing the back surface 1b of each glass substrate 1 at a portion corresponding to between the sealing material 5 and the EL element portion 2, the glass substrate 1 is cut, so that a pair of glasses The substrates 1 are separated from each other.

Embodiment 5
FIG. 9 shows a cross-sectional structure of the bonded substrate W in the fifth embodiment. In this fifth embodiment, the peripheral portions of the pair of glass substrates 1 are bonded to each other through the sealing material 5 in which the spacer particles 8 are mixed in the fourth embodiment. The spacer particles 8 are particles for separating the peripheral portions of the pair of glass substrates 1 from each other at a predetermined interval. The spacer particles 8 are arranged so as not to interfere with each other due to the presence of the spacer particles 8. Is done. As the spacer particles 8, for example, particles having a diameter of several hundred μm are used.

As in the fourth embodiment, it is desirable to adjust the viscosity of the sealing material 5 in order to prevent the sealing material 5 from entering the EL element portion 2.
For example, as shown in FIG. 9, the glass substrate 1 is cut by scribing the back surface 1 b of each glass substrate 1 at a portion corresponding to the space between the sealing material 5 and the EL element portion 2. The substrates 1 are separated from each other.

Embodiment 6
FIG. 10 shows a cross-sectional structure of the bonded substrate W in the sixth embodiment. In the sixth embodiment, a pair of EL devices 3 in which the EL element portion 2 is formed on the entire surface 1a of the pair of glass substrates 1 are used. In this case, the spacer member 4 is arranged between the EL element portions 2 so as to be located outside the effective element portion 2a formed on the center side of each EL element portion 2, and in that state, the sealing material 5 The pair of glass substrates 1 can be bonded together so as to cover the side portions of the pair of glass substrates 1, and then the pair of glass substrates 1 can be thinned.

Embodiment 7
FIG. 11 shows a cross-sectional structure of the bonded substrate W in the seventh embodiment. In the seventh embodiment, the peripheral portions of a pair of large glass substrates 1 each having a large number of EL element portions 2 formed on the surfaces thereof are bonded together via a spacer member 4 and a sealing material 5. In addition, a spacer member 4 is disposed between the EL element portions 2 adjacent to each other at the central portion of the glass substrate 1, whereby the EL element portion 2 on one glass substrate 1 is placed on the other glass substrate 1. A pair of glass substrates 1 are arranged at a predetermined interval so as to be separated from the EL element portion 2.

  Such a bonded substrate W can be immersed in an etching solution to make the pair of glass substrates 1 thinner. In addition, after thinning, a pair of glass substrate 1 is parted mutually by scribing each glass substrate 1 between the bonding part of a peripheral part, and the EL element part 2 adjacent to it, and each part glass further divided | segmented The substrate 1 is divided according to the individual EL element portions 2. Accordingly, a large number of EL devices that are thin and light can be easily obtained.

Embodiment 8
FIG. 12 shows a cross-sectional structure of the bonded substrate W in the eighth embodiment. In the eighth embodiment, the glass substrate 1 is bent by its own weight by eliminating the spacer member 4 disposed between the EL element portions 2 adjacent to each other in the central portion of the glass substrate 1 in the seventh embodiment. The EL element part 2 disposed at the center of the EL element part 2 is brought into contact with the opposing EL element part 2.

Also in this bonded substrate W, as in the seventh embodiment, after the bonded substrate W is immersed in an etching solution to make the pair of glass substrates 1 thin, each glass substrate 1 is bonded to the bonded portion at the peripheral portion and the glass substrate 1. The pair of glass substrates 1 may be separated from each other by scribing between the adjacent EL element portions 2, and the divided glass substrates 1 may be divided according to the individual EL element portions 2.
Since the spacer members 4 arranged between the EL element portions 2 adjacent to each other are abolished, the steps of attaching the spacer members 4 and the steps of removing and removing the spacer members 4 are reduced, and a number of EL device manufactures can be performed. Efficiency can be improved and cost can be reduced.

Embodiment 9
FIG. 13 shows a cross-sectional structure of the bonded substrate W in the ninth embodiment. In the ninth embodiment, instead of pasting the peripheral portions of the pair of glass substrates 1 through the spacer member 4 and the sealing material 5 in the eighth embodiment, only a pair of viscous sealing materials 5 is used. A plurality of EL element portions 2 on one glass substrate 1 and a plurality of EL element portions 2 on the other glass substrate 1 are brought into contact with each other.

In the ninth embodiment, since all the spacer members 4 are eliminated, the steps for attaching the spacer members 4 and the steps for removing and removing the spacer members 4 are reduced, thereby improving the efficiency and cost reduction of manufacturing a large number of EL devices. Can be planned.
In addition, in order to prevent the sealing material 5 arrange | positioned at the peripheral part of a pair of glass substrate 1 from penetrating to the EL element part 2, it is desirable to adjust the viscosity of the sealing material 5. FIG.

Embodiment 10
FIG. 14 shows a cross-sectional structure of the bonded substrate W in the tenth embodiment. In the tenth embodiment, the protective film 9 for protecting the element is formed on the surface of the EL element section 2 which is film-sealed in the ninth embodiment, and the EL element sections 2 facing each other. The protective films 9 are in close contact with each other.

In the tenth embodiment, the protective film 9 has a structure in which the spacer member 4 is substituted. Therefore, since the bending generated when the glass substrate 1 is scribed is limited by the protective film 9, the EL element portion 2 can be reliably protected and the glass substrate 1 can be easily formed without providing the spacer member 4. It is possible to scribe at a predetermined position.
In the tenth embodiment, the protective film 9 is formed on the surface of the sealing film of all the EL element portions 2, but only the EL element portions 2 that may come into contact with each other due to the bending of the glass substrate 1. A protective film 9 may be applied.

In each of the above-described embodiments, the glass substrate 1 is used. However, a substrate made of Si, resin, or metal can be used as the substrate of the EL device.
Further, in each of the above-described embodiments, the pair of glass substrates 1 is etched and thinned. However, the present invention is not limited to this, and a thinning method suitable for the material of the substrate of the EL device, for example, polishing. The substrate can be thinned by various methods such as blasting and blasting. In the case of polishing, the pair of substrates can be simultaneously thinned by performing double-side polishing.

The present invention relates to a bottom emission type EL device in which a transparent electrode, a light emitting layer, and a reflective electrode are sequentially laminated on a substrate, and light emitted from the light emitting layer is emitted through the transparent electrode and the substrate, And a top emission type EL device in which a reflective electrode, a light emitting layer and a transparent electrode are sequentially laminated on the substrate, and light emitted from the light emitting layer is transmitted through the transparent electrode on the opposite side of the substrate and emitted. Applies to
The present invention can be applied to both organic EL devices and inorganic EL devices.

It is a flowchart which shows the thinning method of the board | substrate of the EL apparatus which concerns on Embodiment 1 of this invention. 3 is a diagram showing a state of formation of an EL element portion on each substrate in Embodiment 1. FIG. It is a figure which shows a mode that a thinning process is performed to both the glass substrates of the bonding board | substrate in Embodiment 1. FIG. It is sectional drawing which shows the bonded substrate in Embodiment 1 to which the thinning process was given. FIG. 6 is a cross-sectional view illustrating a bonded substrate in Embodiment 2. FIG. 6 is a plan view showing a bonded substrate in Embodiment 2. 7 is a cross-sectional view illustrating a bonded substrate in Embodiment 3. FIG. FIG. 10 is a cross-sectional view illustrating a bonded substrate in Embodiment 4. 10 is a cross-sectional view showing a bonded substrate in Embodiment 5. FIG. 10 is a partial cross-sectional view illustrating a bonded substrate in Embodiment 6. FIG. 9 is a cross-sectional view illustrating a bonded substrate in Embodiment 7. FIG. 10 is a cross-sectional view illustrating a bonded substrate in Embodiment 8. FIG. 10 is a cross-sectional view illustrating a bonded substrate in Embodiment 9. FIG. 10 is a cross-sectional view illustrating a bonded substrate in Embodiment 10. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Glass substrate, 1a surface, 1b back surface, 2 EL element part, 2a Effective element part, 3 EL apparatus, 4 Spacer member, 5 Sealing material, 6 Hollow part, 7 Bonding part, 8 Spacer particle, 9 Protective film, W Bonded substrate, SL scribe line.

Claims (22)

In a method for thinning a substrate of an EL device having a substrate and an EL element portion formed on the substrate,
A pair of substrates each having an EL element portion formed on the surface thereof are arranged so that the EL element portions face each other,
In that state, the peripheral portions of the pair of substrates are bonded to each other so as to seal each EL element portion from the outside,
A thinning method for a substrate of an EL device, wherein the pair of substrates is thinned.   The method of thinning a substrate of an EL device according to claim 1, wherein etching is performed as the thinning process.   The method of thinning a substrate of an EL device according to claim 1, wherein polishing is performed as the thinning process.   The method of thinning a substrate of an EL device according to claim 1, wherein blasting is performed as the thinning process.   5. The thin substrate of the EL device according to claim 1, wherein the peripheral portions of the pair of substrates are bonded to each other at a predetermined interval so that the respective EL element portions are spaced apart from each other. Method.   6. The method for thinning a substrate of an EL device according to claim 5, wherein the peripheral portions of the pair of substrates are bonded to each other via a sealing material.   The method of thinning a substrate of an EL device according to claim 6, wherein the sealing material includes spacer particles for separating peripheral edges of the pair of substrates at a predetermined interval.   The method of thinning a substrate of an EL device according to claim 6, wherein a spacer member is interposed between the peripheral portions of the pair of substrates.   The method of thinning a substrate of an EL device according to claim 8, wherein the spacer member is a double-sided tape disposed inside the sealing material.   6. The method of thinning a substrate of an EL device according to claim 5, wherein the peripheral portions of the pair of substrates are bonded to each other via a double-sided tape.   The method for thinning a substrate of an EL device according to claim 1, wherein the peripheral portions of the pair of substrates are bonded so that the respective EL element portions are in contact with each other.   The method for thinning a substrate of an EL device according to claim 11, wherein peripheral portions of the pair of substrates are bonded to each other via a sealing material.   The substrate of the EL device according to any one of claims 1 to 12, wherein after the thinning process, the pair of substrates are separated from each other by cutting off a bonded portion of a peripheral portion of the pair of substrates. Method.   The method of thinning a substrate of an EL device according to claim 13, wherein each substrate is cut between a bonded portion at a peripheral portion of the pair of substrates and each EL element portion.   The method for thinning a substrate of an EL device according to claim 8 or 9, wherein after the thinning process, the pair of substrates is separated from each other by cutting each substrate at a portion corresponding to the spacer member.   The method for thinning a substrate of an EL device according to claim 1, wherein the EL element portion formed on the surface of the substrate is film-sealed.   The method for thinning a substrate of an EL device according to claim 16, wherein a protective film is formed on the surface of the EL element portion sealed with the film.   The method for reducing the thickness of a substrate of an EL device according to claim 1, wherein a glass substrate is used as the substrate.   The method for thinning a substrate of an EL device according to claim 1, wherein a plurality of EL element portions are formed on the surface of the substrate. A method of dividing a bonded substrate in which peripheral portions are bonded together in a state where element portions formed on the respective surfaces face each other,
A method for dividing a bonded substrate, comprising: cutting each substrate in a region between the bonded portion of the peripheral portion and the element portion and spaced apart from each other through a hollow portion.   The method for dividing a bonded substrate according to claim 20, wherein each substrate is made of a glass substrate, and each substrate is cut by scribing a surface opposite to the surface on which the element portion is formed.   The method for dividing a bonded substrate according to claim 21, wherein the height of the blade for scribing is set on the basis of the substrate with the lowest thickness tolerance.

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