JP2001307886A - Electric field light-emitting light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric field light-emitting light of a superior quality, in which the cost is reduced by the reduction of the printing number of a reflection insulating layer, and in which the reflection insulating layer is made to be precise and with a high dielectric and in which the insulation resisting pressure and the luminance are improved. SOLUTION: In the electric field light-emitting light 1 wherein a transparent electrode layer 53, a luminous layer 54, reflection insulating layer 2, a rear face electrode layer 56 are laminated, the reflection insulating layer 2 is what is dispersed of barium titanate in fluorine-containing rubber of a low viscosity, which has not more than Mooney viscosity of 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electroluminescent lamp and a method for manufacturing the same, and more particularly to an electroluminescent lamp suitable for a backlight of a liquid crystal display and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional electroluminescent lamp 51 has a structure shown in a sectional view of FIG. 6, for example, and is manufactured as follows.
In FIG. 6, the illustration of the lead connection structure is omitted. First, sputtering is performed on one side of an insulating transparent film 52 made of PET or the like having a thickness of 100 to 200 μm.
A transparent electrode layer 53 of ITO or the like is formed with a thickness of 30 to 50 nm by a thin film forming means under reduced pressure such as electron beam evaporation or CVD.

Next, a phosphor (center particle diameter (median diameter) of 20 to 30 μm) in which zinc sulfide is activated by copper and a binder made of fluororubber are mixed with an organic solvent (for example, isophorone).
Using the light emitting layer ink dispersed therein, the transparent electrode layer 5
The light emitting layer 54 is screen-printed on the sample No. 3 in an amount of
m. The binder uses fluorine rubber excellent in waterproofness in order to prevent deterioration of the phosphor due to moisture. The composition of the ink for the light-emitting layer is such that the weight ratio of fluorine rubber to organic solvent 1 is 0.43 (fluorine rubber concentration is about 3%).
0 wt%), and the weight ratio of the phosphor to the fluororubber 1 is 1.5 to 1.6. The viscosity of the ink is 50,000 to 60,000 so that screen printing can be performed.
It is adjusted to mPa · s (= cP). The mesh of the screen is # 150 to # 250.

Next, a white high dielectric substance made of barium titanate and a general fluoro rubber (for example, a Mooney viscosity of about 60) are coated on the light emitting layer 54 with an organic solvent (for example,
Using the ink for a reflective insulating layer dispersed in isophorone), the reflective insulating layer 55
Printed to a thickness of μm. The binder solution obtained by dissolving the fluorine rubber in the organic solvent has a fluorine rubber concentration of about 30 wt% and a viscosity of about 30,000 mPa · s. Barium titanate is dispersed in the binder solution at a weight ratio of 0.8 to 0.9 with respect to the fluororubber 1 to obtain a reflective insulating layer ink. The viscosity of this ink is adjusted to about 80000 mPa · s, which enables screen printing by mass production. The mesh of the screen is # 120 to # 200.

Next, a back electrode layer 56 made of a conductive paste such as silver or carbon is formed on the reflective insulating layer 55 by screen printing to a thickness of 10 to 20 μm.

Next, a protective layer 57 made of an insulating resin such as a melamine resin, a phenol resin, or an epoxy resin is formed on the back electrode layer 56 by screen printing, and the electroluminescent lamp 51 is obtained.

In order to turn on the electroluminescent lamp 51, an IC for converting a low DC voltage into a high AC voltage such as a battery is usually used.
A driving device (not shown) such as an inverter is used. This type of inverter includes a DC power supply, an inductor (such as a choke coil or a transformer), and a switching element. In operation, first, a switch is turned on, a current flows from a power supply to an inductor to store energy in the inductor, and then, the switch is turned off to release the energy to charge a capacitive load of the electroluminescent lamp. Thereafter, the terminal voltage of the electroluminescent lamp is increased by repeating on / off (step-up method). When the voltage becomes sufficiently high, the electroluminescent lamp is discharged to emit light, and charge and discharge are repeated to maintain light emission.

[0008]

The viscosity and composition of the ink for the light emitting layer are determined with emphasis on screen printability so that a high quality light emitting layer having a predetermined thickness can be formed by printing. Increasing the binder concentration with respect to the organic solvent tends to increase the viscosity, but too high a viscosity is not suitable for screen printing. Because of the high viscosity of fluororubber, the allowable concentration on printing is low, and the binder concentration has to be set to about 30% by weight as described above. When the ratio of the phosphor is increased, the viscosity of the ink is increased. For the same reason, the ratio of the phosphor to the binder 1 is 1.5% by weight.
１1.6 had to be set.

[0009] However, the above-mentioned ink for a light emitting layer has almost no problem in printing, but has a problem in characteristics.
That is, the light emitting layer printed and formed using this ink is:
As shown in the cross-sectional view of the main part of FIG. 7, when the organic solvent evaporates during drying due to insufficient binder concentration and the volume of the binder is reduced, the binder is placed between the phosphor 58 and the binder 59, in the binder 59, and the like. Bubbles 60 are generated and the binder 5
There was a problem that the film thickness of No. 9 was reduced and the withstand voltage was reduced. Further, there is also a problem that the amount of the binder is insufficient and only a small part of the phosphor is buried in the binder, voltage is not effectively applied to the phosphor, and the luminance is insufficient.

On the other hand, the viscosity and composition of the ink for the reflective insulating layer are also determined in consideration of the screen printability.
The binder concentration was set at about 30 wt%. Therefore, although printability is good, binder density is insufficient,
Since the weight ratio of barium titanate that can be dispersed in the binder is insufficient, the film thickness that can be formed by one printing is small due to a decrease in volume after drying. For this reason, in order to obtain a reflective insulating layer having a predetermined withstand voltage, it is necessary to perform printing twice or more, resulting in a problem that the number of steps increases and the cost increases.

The present invention has been made in view of the above problems, and has as its object to provide an inexpensive, high-brightness electroluminescent lamp in which the number of times of printing the reflective insulating layer is reduced to reduce the cost. It is another object of the present invention to provide an inexpensive and high-brightness electroluminescent lamp in which the number of times of printing of the reflective insulating layer is reduced to reduce the cost, and the gap of the light emitting layer is eliminated to improve the withstand voltage.

[0012]

An electroluminescent lamp according to the present invention comprises:
In an electroluminescent lamp in which a transparent electrode layer, a light emitting layer, a reflective insulating layer, and a back electrode layer are laminated, the reflective insulating layer is made of titanic acid in a low-viscosity fluororubber having a Mooney viscosity (JIS K 6200 "rubber term") of 20 or less. It is characterized in that barium is dispersed. With this configuration, the weight ratio of barium titanate to the binder can be increased, so that a reflective insulating layer having a dense and high dielectric constant can be provided, and a high-quality electroluminescent lamp having improved withstand voltage and luminance can be provided.

The electroluminescent lamp of the present invention is an electroluminescent lamp in which a transparent electrode layer, a luminescent layer, a reflective insulating layer, and a back electrode layer are laminated. Is dispersed in a ratio of 3.6 / c to 5.0 / c (weight ratio), and the reflective insulating layer is obtained by dispersing barium titanate in a low-viscosity fluororubber having a Mooney viscosity of 20 or less. It is characterized by. With this configuration, in addition to the above-described functions and effects, the volume ratio of the binder and the phosphor in the light emitting layer becomes appropriate, and the phosphor is dispersed in the binder in the optimum state, so that the gap in the light emitting layer is eliminated, and the withstand voltage is improved. An electroluminescent lamp with improved brightness can be provided.

In the electroluminescent lamp according to the present invention, the reflective insulating layer has barium titanate having a weight ratio of 2.6 to 3.2 dispersed in low-viscosity fluororubber 1 having a Mooney viscosity of 20 or less. Characterized in that: This configuration is a specific appropriate range in which a dense and high dielectric constant reflective insulating layer can be formed by printing.

Further, the electroluminescent lamp of the present invention is characterized in that the binder of the light emitting layer is a polyester resin. With this configuration, the binder becomes low in viscosity, so that the binder concentration and the phosphor weight ratio can be increased, the volume ratio of the binder and the phosphor in the light emitting layer becomes appropriate, and the phosphor is dispersed in the binder in an optimal state, so the light emitting layer This eliminates the voids, improves the dielectric strength, and provides an electroluminescent lamp with improved luminance.

Further, the method for manufacturing an electroluminescent lamp according to the present invention comprises:
In the method for manufacturing an electroluminescent lamp in which a light emitting layer, a reflective insulating layer, and a back electrode layer are formed on a transparent electrode layer, the concentration of the low-viscosity fluororubber having a Mooney viscosity of 20 or less is 35 to 45.
2.6% to 3.2% (weight ratio) of barium titanate with respect to 1 of the low-viscosity fluororubber is dispersed in a binder solution having a viscosity of 50,000 to 80,000 mPa · s to obtain a reflection insulating layer ink. The reflective insulating layer is formed by screen printing using With this configuration, a dense and high-dielectric-constant reflective insulating layer having a predetermined
Since it can be formed by multiple screen printings, a high-quality electroluminescent lamp with improved withstand voltage and brightness can be manufactured at low cost.

Further, the method for manufacturing an electroluminescent lamp according to the present invention comprises:
In a method for manufacturing an electroluminescent lamp in which a light emitting layer, a reflective insulating layer, and a back electrode layer are formed on a transparent electrode layer, a resin having a specific gravity c with respect to a solvent 1 is 0.8c to 1.3c (weight ratio). 2. In the dispersed binder solution, add 3.
A phosphor of 6 / c to 5.0 / c (weight ratio) is dispersed to form an ink for a light emitting layer having a viscosity of 30,000 to 80000 mPa · s, and the light emitting layer is formed by screen printing using this ink. In a binder solution having a viscosity of 35 to 45% by weight of a low-viscosity fluororubber having a viscosity of 20 or less, 2.6 to 3.2 (weight ratio) of barium titanate is dispersed with respect to the low-viscosity fluororubber 1 to obtain a viscosity. 50,000 ~
It is characterized in that the ink for a reflective insulating layer is 80000 mPa · s, and the reflective insulating layer is formed by screen printing using this ink. With this configuration, the volume ratio of the binder and the phosphor in the light emitting layer becomes appropriate, and the phosphor is dispersed in the binder in an optimal state, so that the gap of the light emitting layer is eliminated, the withstand voltage is improved, and the brightness of the electroluminescent lamp is improved. Can be manufactured. In addition, a dense and high dielectric constant reflective insulating layer
Since it can be formed by multiple screen printings, a high-quality electroluminescent lamp with improved withstand voltage and brightness can be manufactured at low cost.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The feature of the first embodiment of the electroluminescent lamp according to the present invention is that it has a reflective insulating layer in which barium titanate is dispersed in a binder made of a low-viscosity fluororubber having a Mooney viscosity of 20 or less. That is. Specifically, barium titanate having a weight ratio of 2.6 to 3.2 is dispersed in the binder 1. With this configuration, the binder concentration can be increased without increasing the viscosity of the ink for the reflective insulating layer, and the weight ratio of barium titanate to the binder can be increased. And an inexpensive electroluminescent lamp with improved withstand voltage and brightness can be provided.

The characteristics of the production method are the composition and viscosity of the ink for the reflective insulating layer. Composition of ink for reflective insulating layer,
The viscosity is determined from both printability and characteristics. When the binder concentration with respect to the solvent is low, the weight ratio of barium titanate that can be dispersed becomes small, and the relative dielectric constant of the reflective insulating layer decreases, which causes a decrease in luminance. Further, a sufficient film thickness cannot be ensured due to a decrease in volume after drying. Conversely, if the binder concentration with respect to the solvent is high, the weight ratio of barium titanate that can be dispersed increases, and the relative dielectric constant increases. In addition, pinholes occur in the coating film, and the withstand voltage decreases. Therefore, in order to form a dense and thick reflective insulating layer by one screen printing, the binder concentration with respect to the solvent is set to be larger than the conventional 30 wt%, and the weight ratio of barium titanate to the binder is set to be larger than the conventional case. In addition, an ink for a reflective insulating layer having an appropriate viscosity is required. Such a reflective insulating layer ink can be realized by using a fluororubber having a lower viscosity (Mooney viscosity of 20 or less) as a binder than before.

Since the ink for the reflective insulating layer in the first embodiment uses a low-viscosity fluororubber having a Mooney viscosity of 20 or less as a binder, a conventional general fluororubber (with a Mooney viscosity of about 60) is used. The viscosity of the binder solution is greatly reduced as compared with the case. Therefore, the maximum concentration of the binder with respect to the organic solvent within the allowable printable viscosity can be higher than the conventional 30 wt%, and can be increased to 45 wt%. In order to form a reflective insulating layer having a thickness of 10 to 20 μm by one printing, a binder concentration of 35 wt% or more is necessary from experience. Conventional 3
It can be set to a concentration of 35 to 45 wt%, which greatly exceeds 0 wt%. When a fluororubber having a Mooney viscosity of more than 20 is used, the maximum binder concentration is greatly reduced from 45 wt% and approaches the minimum concentration of 35 wt%, and the variation in the binder concentration during mass production cannot be tolerated. The barium titanate that can be dispersed in the 35 to 45 wt% binder solution is 2.6 to 3.2 in weight ratio to the binder 1, which is sufficiently larger than the conventional 0.8 to 0.9. The ink for the reflective insulating layer has a viscosity of 50,000 to 80000 mP even though the binder concentration and the phosphor weight ratio are increased as compared with the prior art.
a · s, which is suitable for screen printing. Since this ink contains a large amount of solid components such as a binder and barium titanate, the thickness of the reflective insulating layer is increased, and a high-quality reflective insulating layer of 10 to 20 μm can be formed by one screen printing. Since the number of times of printing can be reduced from two or more times in the past to one time, the cost can be reduced. In addition, since the reflective insulating layer has a high ratio of barium titanate to the binder, the dielectric constant increases, the voltage loss is reduced, and the voltage is effectively applied to the light emitting layer, so that the light emitting efficiency is improved. It is dense, has no pinholes, and has a high dielectric strength. Incidentally, the binder concentration,
If the weight ratio is less than the lower limit of the ink viscosity, 10 to 20 μm
m cannot be formed by one printing. On the other hand, if the ratio exceeds each upper limit, the printing speed becomes slow due to excessive viscosity, and mass productivity is lowered. Further, a flat layer cannot be formed.

[0021]

Embodiment 1 Next, an embodiment of the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an electroluminescent lamp 1 of the present invention. The configuration other than the reflective insulating layer is the same as the conventional example of FIG. The manufacturing method is as follows.
On one surface of an insulating transparent film 52 made of PET or the like having a thickness of 0 to 200 μm, a transparent electrode layer 53 such as ITO
It is formed with a thickness of 50 nm.

Next, a phosphor (center particle diameter (median diameter) of 20 to 30 μm) obtained by activating zinc sulfide with copper and a binder made of fluororubber are mixed with an organic solvent (for example, isophorone).
The light emitting layer 54 is formed on the transparent electrode layer 53 by screen printing using the conventional light emitting layer ink dispersed therein.
It is formed to a thickness of 0 to 50 μm. The composition and viscosity of the ink are the same as in the prior art, and a description thereof will be omitted.

Next, on the light-emitting layer 54, a white high-dielectric substance made of barium titanate and a low-viscosity fluororubber having a Mooney viscosity of 20 or less as a binder (for example, A215, N215 (Mooney viscosity: about 10)) Is used to form a reflective insulating layer 2 with a thickness of 10 to 20 μm by one screen printing using an ink for a reflective insulating layer in which is dispersed in an organic solvent. Desirable composition range of ink (weight ratio)
Is solvent: binder: barium titanate 1: 0.5
4: 1.40 to 1: 0.82: 2.62. The ink for the reflective insulating layer is prepared as follows. First, the low-viscosity fluororubber is dissolved in an organic solvent 1 composed of isophorone in a weight ratio of 0.54 to 0.82 to obtain a binder solution having a concentration of 35 to 45% by weight. The viscosity of the binder solution is 15000
４０40000 mPa · s. Next, a weight ratio of 2.6 (= 1.40 / 0.54) to 3.2 (= 2.62) with respect to 1 of the binder (low-viscosity fluororubber) is added to the binder solution.
/0.82) to form a reflective insulating layer ink. The viscosity of the ink for the reflective insulating layer is 5000
It is 0 to 80000 mPa · s. The screen mesh is appropriately selected from # 120 to # 200.

Next, a back electrode layer 56 is formed on the reflective insulating layer 2.
Is formed by printing, and a protective layer 57 is formed by printing thereon.
The material and the forming method are the same as those in the related art, and the description is omitted.

Next, a description will be given of a second embodiment of the electroluminescent lamp according to the present invention. A feature of the second embodiment is that an improved light emitting layer is provided in addition to the reflective insulating layer of the first embodiment. For this reason, the number of times of printing of the reflective insulating layer is reduced, the cost is reduced, and the volume ratio between the binder and the phosphor in the light emitting layer becomes appropriate, and the phosphor is dispersed in the binder in an optimal state, so that the luminance is improved and the light emission is improved. There is no gap between the layers, and the withstand voltage is improved.

A desirable form of the light emitting layer for improving the withstand voltage and obtaining high luminance is, as shown in a schematic cross-sectional view of a main part of FIG. Approximately half of this is buried in the binder 5. In the schematic diagram of FIG. 2, the phosphor is displayed as a true sphere. In such a light emitting layer 6, a voltage is effectively applied to the phosphor via the binder 5, so that the luminance is improved. Further, since the amount of the binder is increased as compared with the related art, the gap is reduced, and the withstand voltage is improved. FIG. 2 shows the case where the phosphors are in contact with each other, which has the highest density and is most advantageous in terms of luminance.

In order to realize this state, it is necessary to set the volume ratio between the binder and the phosphor within an appropriate range. According to the study of the inventor, in order to obtain the light emitting layer having the form shown in FIG.
It is desirable to use a resin having a lower viscosity than conventional fluororubber for the binder to increase the binder concentration with respect to the solvent and the weight ratio of the phosphor to the binder. That is, a resin having a low specific gravity and a low viscosity having a specific gravity c of about 0.8 to 1.6 is used, and the binder concentration with respect to the solvent 1 is set at 0.1 by weight.
It is desirable to set it in the range of 8c to 1.3c.

Further, in order to obtain the state of the light emitting layer shown in FIG. 2, in the binder solution in which the binder concentration with respect to the solvent 1 is in the range of 0.8c to 1.3c by weight, the phosphor with respect to the binder is used. The weight ratio needs to be within an appropriate range. When the specific gravity of the binder is c, 3.6 /
c to 5.0 / c is an appropriate range of the phosphor weight ratio to the binder 1.

[0029]

Embodiment 2 Next, an embodiment of the second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a sectional view of the electroluminescent lamp 3 of the present invention. The configuration other than the light emitting layer 6 is shown in FIG.
This is the same as the electroluminescent lamp 1 of the first embodiment, except for the light emitting layer. The electroluminescent lamp 3 according to the present invention is manufactured as follows. First, 100-200 μm thick PET
One side of an insulating transparent film 52 made of
The transparent electrode layer 53 is formed with a thickness of 30 to 50 nm.

Next, the phosphor 4 in which zinc sulfide was activated with copper was used.
The light emitting layer 6 is formed on the transparent electrode layer 53 by screen printing to a thickness of 30 to 50 μm (after drying) using a binder 5 made of a polyester resin and an ink for a light emitting layer made of an organic solvent. The light emitting layer ink is prepared as follows. First, a polyester resin having a specific gravity of 1.2 is added to an organic solvent composed of ethylene glycol in an amount of 50 to 60 wt%.
(The weight ratio of the resin to the solvent 1 is 1 to 1.5) to obtain a binder solution having a viscosity of 10,000 to 30,000 mPa · s. Next, a phosphor (center particle diameter (median diameter) of 20 to 30 μm) is uniformly dispersed in the binder solution to obtain a light emitting layer ink having a viscosity of 30,000 to 80,000 mPa · s. The desirable composition of the ink for the light emitting layer is such that the weight ratio of solvent: binder: phosphor is from 1: 1: 3 to
1: 1.5: 6.25. Therefore, the weight ratio of the binder to the solvent 1 is 1 to 1.5. The weight ratio of the phosphor to the binder 1 is 3 to 4.16.
The viscosity of the ink is adjusted to 30,000 to 80,000 mPa · s so that screen printing can be performed at a speed suitable for mass production. If the viscosity of the ink is less than 30,000 mPa · s, the ink is too thin to form a light emitting layer having a predetermined thickness. On the other hand, if it exceeds 80000 mPa · s, the printing speed becomes slow and the mass productivity is reduced. Screen mesh is # 15
0 to # 200. In each of the above ranges of concentration, weight ratio, and viscosity, each lower limit corresponds, and each upper limit also corresponds. Under the conditions between the upper limit and the lower limit, a light emitting layer in a form shown in FIG. The definition of the median particle size (median diameter) is defined as the particle size and the% under the integrated sieve (cumulative mass (volume)) measured by the sieving test method described in JIS Z8815 (1994) “General rules for sieving test method”. %), The particle size when the integrated sieve lower% is 50% is the central particle size.

Next, on the light emitting layer 6, the reflective insulating layer 2 is formed by screen printing once using the same ink for the reflective insulating layer as in the first embodiment to a thickness of 10 to 20 μm. I do. The description of the composition and viscosity of the ink is omitted.

Next, a back electrode layer 56 is formed on the reflective insulating layer 2.
Is formed by printing, and a protective layer 57 is formed by printing thereon.
The material and the forming method are the same as those in the related art, and the description is omitted.

The polyester resin used for the binder 5 of the light emitting layer 6 in the second embodiment has a specific gravity c of about 1.2.
The viscosity of the binder solution when dissolved in an organic solvent is sufficiently smaller than that of a conventional fluororubber. Therefore, in the binder solution in which the polyester resin is dissolved, the binder concentration with respect to the solvent can be increased within the allowable viscosity for printing. Conventional fluorine rubber upper limit concentration 30wt%
In contrast, the concentration can be increased to 50 to 60% by weight (1 to 1.5 by weight) with respect to the polyester resin (about 0.43 by weight to solvent 1). Therefore, the weight of the phosphor that can be dispersed in the binder solution can be increased without increasing the viscosity much. Since the weight ratio of the phosphor to the binder solution can be increased to a maximum of 2.5 within the allowable viscosity on printing (up to about 1.6 in the case of the conventional fluororubber), the phosphor filling rate of the binder in the light emitting layer increases. As a result, the particle spacing of the phosphor is narrowed, and uneven brightness is reduced, so that high brightness can be realized.
In the light emitting layer 6 formed by the manufacturing method of the present invention, since the volume of the polyester resin is large (specific gravity is small),
As shown in the schematic cross-sectional view of the main part of FIG. 2, since the binder 5 is thicker than in the related art, almost half of the phosphor 4 is buried in the binder, and a voltage is effectively applied to the phosphor to improve the luminance. . Further, bubbles generated between the phosphor 4 and the binder 5 and in the binder 5 and the like are drastically reduced, and the withstand voltage is improved. The binder of the light emitting layer 6 is not limited to the polyester resin described above, and a resin having a lower viscosity and a smaller specific gravity than conventional fluororubber is suitable. Further, it is optimal if the relative permittivity is large (10 or more).

According to the results of Example 2, when the binder of the light emitting layer is made of a polyester resin having a specific gravity of 1.2, the binder concentration is set to 50 to 60 wt% (the binder weight ratio to the solvent is 1 to 1.5). When the weight ratio of the phosphor to the binder is 3 to 4.16, the luminance and the dielectric strength are improved. Under these conditions, the arrangement of the binder and the phosphor in the light-emitting layer is in the desirable form shown in FIG. Empirically, the form of the light-emitting layer depends on the volume ratio of the phosphor to the binder, so that a desirable weight ratio of 3-4.
When 16 is converted into a volume ratio, it is 0.878 to 1.22. Since the phosphor increases relatively near the volume ratio of 1.22, the density of the phosphor increases. 0.8 volume ratio
In the vicinity of 78, the number of phosphors relatively decreases, so that the density of the phosphors is reduced. The volume ratio is V / v = (M
/ M) · (c / C) as C = 4.1 and c = 1.2. Here, the volumes of the phosphor and the binder were V and v, the weights were M and m, respectively, and the specific gravities were C and c, respectively. M / m is a weight ratio. Also, M
= CV, m = cv.

Using the weight ratio of the phosphor to the polyester resin, the weight ratio of the phosphor to another resin having a specific gravity c can be determined. Also in this case, the above-mentioned volume ratio is desirable. Therefore, the range of the desirable weight ratio for an arbitrary binder having a specific gravity c is M / m = C (V / v) / c from the above equation.
= 3.6 / c to 5.0 / c (where C = 4.1, V / v
= 0.878 to 1.22. ). The relationship between the specific gravity c and the phosphor weight ratio M / m is plotted in FIG. FIG.
The region between the solid line A1 and the solid line A2 is a preferable range. FIG.
Are confirmed by experiments.

The binder concentration range of the polyester resin is 50 to 60% by weight (the weight ratio of the binder to the solvent is 1%).
To 1.5), the binder concentration range when a binder having a specific gravity c other than the polyester resin is used can be calculated. Desirable weight ratio of polyester resin 1 to 1
A desirable volume ratio corresponding to 1.5 is 0.8 (= 1 / 1.2) to 1.3 (= 1.5 / 1.2) when the specific gravity is 1.2. Also in the case of other binders having a specific gravity c, the desirable volume ratio is 0.8 to 1.3, so that the weight ratio of the other binder having the specific gravity c to the solvent can be represented by 0.8c to 1.3c. The relationship between the specific gravity c and the binder weight ratio is plotted in FIG. The region between the solid line B1 and the solid line B2 in FIG. 5 is the preferred range. The results in FIG. 5 have been confirmed by experiments.

In FIG. 4, the solid line A1 corresponds to the maximum value of the ink viscosity (about 80,000 mPa · s). The solid line A2 represents the minimum value of the ink viscosity (about 30,000 mPa · s).
Corresponding to In FIG. 5, the solid line B1 corresponds to the maximum value of the binder solution viscosity (about 30,000 mPa · s). The solid line B2 corresponds to the minimum value (about 10,000 mPa · s). If it exceeds A1 and B1, the viscosity becomes too high to make it unsuitable for screen printing. If it is less than A2 or B2, the viscosity is insufficient and the printing becomes unsuitable.

[0038]

According to the present invention, a reflective insulating layer is formed by using a reflective insulating layer ink in which barium titanate is dispersed in a binder solution in which a low-viscosity fluororubber having a Mooney viscosity of 20 or less is dissolved. Since the solid component can be increased without increasing the ink viscosity, a high-quality reflective insulating layer having a predetermined thickness can be formed by one printing, and an inexpensive and high-quality electroluminescent lamp can be provided.

In addition, a high-quality reflective insulating layer having a predetermined thickness is formed by one printing using the ink for a reflective insulating layer, and a phosphor is dispersed in a binder solution in which a resin having a low viscosity and a small specific gravity is dissolved. By forming the light emitting layer using the ink for the light emitting layer, the dispersion state of the phosphor is optimized, the generation of voids is prevented, the withstand voltage is improved, and the luminance is improved. An electroluminescent lamp can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electroluminescent lamp according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part for describing a desirable mode of a light emitting layer.

FIG. 3 is a sectional view of an electroluminescent lamp according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a phosphor weight ratio of a light emitting layer to a binder and a specific gravity of the binder.

FIG. 5 is a diagram showing a relationship between a binder weight ratio and a binder specific gravity of a binder solution for a light emitting layer.

FIG. 6 is a cross-sectional view of a conventional electroluminescent lamp.

FIG. 7 is a sectional view of a main part of a light emitting layer of a conventional electroluminescent lamp.

[Explanation of symbols]

 1, 3 electroluminescent lamp 2 reflective insulating layer 4 phosphor 5 binder 6, 54 light emitting layer 52 transparent film 53 transparent electrode layer 56 back electrode layer 57 protective layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H05B 33/10 H05B 33/10 33/20 33/20 33/24 33/24

Claims (7)

[Claims] 1. An electroluminescent lamp having a transparent electrode layer, a light emitting layer, a reflective insulating layer and a back electrode layer laminated thereon, wherein said reflective insulating layer comprises barium titanate dispersed in a low-viscosity fluororubber having a Mooney viscosity of 20 or less. An electroluminescent lamp, comprising: 2. An electroluminescent lamp in which a transparent electrode layer, a light-emitting layer, a reflective insulating layer, and a back electrode layer are laminated, wherein the light-emitting layer is composed of a resin 1 having a specific gravity c and a phosphor of 3.6 / c to 5 / c. .0 / c
(Weight ratio) An electroluminescent lamp in which the reflective insulating layer is a dispersion of barium titanate in a low-viscosity fluororubber having a Mooney viscosity of 20 or less. 3. The reflection insulating layer according to claim 1, wherein 2.6 to 3.2 (weight ratio) of barium titanate is dispersed in the low-viscosity fluororubber 1. Item 3. An electroluminescent lamp according to item 2. 4. The electroluminescent lamp according to claim 2, wherein the resin of the light emitting layer is a polyester resin. 5. A light-emitting layer, a reflective insulating layer,
In a method of manufacturing an electroluminescent lamp in which a back electrode layer is formed by lamination, a binder solution having a Mooney viscosity of 20 or less and a low-viscosity fluororubber having a concentration of 35 to 45 wt% is added to a low-viscosity fluororubber of 2.6 to 3 with respect to low-viscosity fluororubber 1. 2. A method for producing an electroluminescent lamp, wherein a reflective insulating layer is formed by screen printing using an ink for a reflective insulating layer in which barium titanate of 2 (weight ratio) is dispersed. 6. A light emitting layer, a reflective insulating layer,
In a method for manufacturing an electroluminescent lamp in which a back electrode layer is formed by lamination, a resin having a specific gravity c with respect to a solvent 1 is 0.8c to 1.3c.
(Weight ratio) Resin 1 of specific gravity c is added to the dispersed binder solution.
A light emitting layer is formed by screen printing using a light emitting layer ink in which a phosphor of 3.6 / c to 5.0 / c (weight ratio) is dispersed, and then a Mooney viscosity of 20 or less. In a binder solution in which the concentration of the viscous fluororubber is 35 to 45 wt%, 2.6 to 3.2 with respect to the low-viscosity fluororubber 1
A method for manufacturing an electroluminescent lamp, comprising forming a reflective insulating layer by screen printing using a reflective insulating layer ink in which barium titanate (weight ratio) is dispersed. 7. The method according to claim 6, wherein the resin of the light emitting layer is a polyester resin.