JP2000306508A - Light emitting element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance display brightness by phosphor layers by improving light transmissivity of an insulating layer covering black matrices(BMs) formed on an anode substrate. SOLUTION: BMs 32 made of Cr/CrOx are formed at the inner surface of an anode substrate 31 of a field emission display(FED). The BM 32 is composed of a Cr/CrOx layer on the anode substrate 31 and a Cr layer laminated on the Cr/CrOx layer. An insulating layer 33 is formed in such a manner as to cover the conductive BM 32 and the anode substrate 31, and further, anode conductors 34 are mounted on the insulating layer 33. Phosphor layers 35 are mounted on the anode conductor 34. A protective layer 36 is formed on the insulating layer 33 in such a manner as to cover the anode conductors 34. The thickness of the BM 32 is as thin as 1500 Å. It is sufficient that the insulating layer 33 for smoothening the BM 32 also is thinner than conventional. A thin insulating layer of a good quality can be formed by sputtering or CVD. Consequently, insulating properties between the adjacent anode conductors 34, 34 can become excellent. The thickness of the insulating layer 33 is so thin that its light transmittance becomes 98%, thereby reducing degradation of lighting brightness of the FED. Since the baking temperature of the phosphor layer is 520 deg.C or lower, an increase in reflectivity of the BM becomes twice or less that in the case where no heat treatment is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device having a black matrix formed around an anode serving as a light emitting display section, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A field emission type light emitting device 1 (FED, Field Emission Display) shown in FIG.
Is a thin panel-shaped envelope 2 whose inside is in a high vacuum state.
have. In this envelope 2, the cathode substrate 3 and the anode substrate 4 face each other at a small interval, and a sealing member (not shown) is provided between the outer peripheral portions of the substrates 3 and 4 for sealing. It has a structure.

[0003] As shown in FIG. 4, an anode 5 is provided on the inner surface of an anode substrate 4 inside the envelope 2. The anode 5 has an anode conductor 6 made of a transparent conductive film formed in a predetermined pattern, and a phosphor layer 7 provided on the surface of the anode conductor 6.

As shown in FIG. 4, a field emission type cathode 10 is provided on the inner surface of the cathode substrate 3. The field emission cathode 10 includes a striped cathode conductor 11 provided on the inner surface of the cathode substrate 3 and a striped gate electrode 1 disposed above the cathode conductor 11 so as to intersect with the cathode conductor 11.
2 and both electrodes constitute a matrix. The cathode conductor 11 and the gate electrode 12 are insulated by an insulating layer. At the intersection of the cathode conductor 11 and the gate electrode 12, an emitter 13 that emits electrons is provided in conduction with the cathode conductor 11.

[0005] As shown in FIG. 5, a black matrix 20 may be provided on the inner surface of the anode substrate 4 in order to improve the visibility of light-emitting display by the phosphor layer.

For example, in the structure of the anode shown in FIG. 5, the black matrix 2 is formed on the inner surface of the anode substrate 4 in a predetermined pattern.
0 is formed. The material of the black matrix 20 is limited to an inorganic pigment having excellent heat resistance because the manufacturing process of the FED includes a firing step. For example, (Cu-Cr-Mn) O, (Cu-Fe-Cr) O, which are composite oxides, can be used. Such an inorganic pigment is mixed with a photosensitive material to form a paste. This is coated on the anode substrate 4 and dried. This is exposed and developed through a mask provided with openings of a predetermined pattern. When this is fired, a black matrix 20 having a predetermined pattern is formed.

[0007] A transparent insulating layer 21 is formed on the inner surface of the anode substrate 4 so as to cover the black matrix 20 to smooth the unevenness of the black matrix 20. This insulating layer 21 is made of low melting point glass or the like. On the insulating layer 21, the anode conductor 6 is formed at a position corresponding to the opening of the black matrix 20. The anode conductor 6 is translucent and made of, for example, ITO (Indium Tin Oxide). A phosphor layer 7 is formed on the anode conductor 6.
Then, a protective film 22 is formed so as to cover the anode conductor 6 and the insulating layer 21 so that the phosphor layer 7 is exposed. The protection film 22 is made of an insulating material such as SiN or SiO ₂ . FE
In the case of D, the anode voltage is often increased from the viewpoint of improving the brightness.
Can prevent discharge from occurring at the corners of the anode conductor 6.

[0008]

(1) Since the conventional inorganic pigment constituting the black matrix has a weak hiding power, the thickness of the black matrix is increased in order to obtain a necessary hiding power. Then, the thickness of the insulating layer for flattening the irregularities of the black matrix also increases,
For example, the thickness of a low-melting glass is 10 to 15 μm. Therefore, the overall thickness of the FED becomes large.

(2) Since the black matrix formed from the inorganic pigment is a mass of particles, irregularities are formed on the film surface and voids are formed inside. For this reason, SiO _x is formed on the black matrix as an insulating layer by sputtering.
, A good film cannot be formed. Therefore, to smooth the black matrix,
As described in (1), the low melting point glass is used, but the transmittance of the low melting point glass is about 90%, which is considerably lower than 98% of the SiO ₂ layer formed by the sputtering method. The drop is large.

(3) A black matrix formed of an inorganic pigment has a low film strength and cannot be touched, so that it cannot be washed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. An insulating layer covers a black matrix on an anode substrate, and an anode serving as a light emitting display section is formed on the insulating layer. It is an object of the present invention to improve the light transmittance of an insulating layer in a light emitting element and to improve display luminance by a phosphor layer.

[0012]

A light emitting device according to claim 1 is formed on an inner surface of an anode substrate (31) constituting a part of an envelope, and has a metal oxide layer on the anode substrate side. A light emitting element having a black matrix (32) composed of two metal layers formed thereon, characterized in that it is fired at a predetermined temperature at which the reflectance of the black matrix becomes a predetermined value or less.

According to a second aspect of the present invention, in the light emitting device according to the first aspect, the predetermined temperature is 520 ° C.
It is characterized as follows.

According to a third aspect of the present invention, in the light emitting device according to the first aspect, the light emitting element has the anode substrate (31) having a phosphor layer (35), and the anode substrate is formed of the anode substrate. The phosphor layer is fired at a predetermined temperature higher than a temperature required for firing.

According to a fourth aspect of the present invention, in the light emitting device according to the first aspect, the black matrix (32) includes two layers of a Cr layer and a CrO _X layer or a Ni layer and an N layer.
It is characterized by comprising two layers of iO _X layer.

A light emitting device according to a fifth aspect is formed on the inner surface of an anode substrate (31) constituting a part of an envelope,
A black matrix (32) comprising two layers of the metal oxide layer on the anode substrate side and a metal layer formed thereon;
In a light emitting device having an insulating layer (33) covering the black matrix, the insulating layer (33) is made of the same insulating material formed in a plurality of times.

According to a sixth aspect of the present invention, in the light emitting device according to the fifth aspect, the insulating layer (33) is formed of one or more of:
It is characterized by having two layers of SiO ₂ , SiN or SiON having a thickness of μm or more.

According to a seventh aspect of the present invention, there is provided a method for manufacturing a light emitting device, wherein the metal oxide layer is formed on an inner surface of an anode substrate (31) constituting a part of an envelope, and the metal oxide layer on the anode substrate side is formed thereon. In the method for manufacturing a light emitting device having a black matrix (32) composed of two metal layers formed as described above, firing is performed at a predetermined temperature at which the reflectance of the black matrix is equal to or lower than a predetermined value.

According to an eighth aspect of the present invention, in the method of manufacturing the light emitting element according to the seventh aspect, the black matrix (32) is fired at a temperature of 520 ° C. or less. I have.

According to a ninth aspect of the present invention, in the method for manufacturing a light emitting element according to the seventh aspect, the anode substrate (3) in which the light emitting element has a phosphor layer (35) is provided.
1) wherein the anode substrate is fired at a predetermined temperature higher than a temperature required for firing the phosphor layer.

The method of manufacturing the light emitting device of claim 10 is a method of manufacturing a light emitting device according to claim 7, wherein the black matrix (32), and two-layer or Ni layer of Cr layer and the CrO _X layer It is characterized in that it is formed from two NiO _X layers.

A method of manufacturing a light emitting device according to claim 11, wherein the metal oxide layer is formed on the inner surface of the anode substrate (31) constituting a part of the envelope, and the metal oxide layer on the anode substrate side and the A black matrix (32) composed of two metal layers formed on the substrate, and an insulating layer (3) covering the black matrix.
The method for manufacturing a light-emitting device having the feature (3) is characterized in that the insulating layer (33) is formed of the same insulating substance in a plurality of times.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The light emitting device of this embodiment is an FED (Field E).
mission Display). The black matrix of the FED includes two layers of a metal and a metal oxide. As a specific example, Cr / Cr used in a liquid crystal display device is used.
Consists of O _x . As shown in FIG. 3 (20), the inner surface of the anode substrate 31, which constitutes a part of the envelope of the FED, has a Cr / C
There is a black matrix 32 made of rO _x . The black matrix 32 is formed of CrO formed on the anode substrate 31.
_{An x} layer and a Cr layer formed on the CrO _x layer. Light transmitted through the anode substrate 31 is partially reflected at the interface between the anode substrate 31 and CrO _x , and partially reflected from the CrO _x.
/ CrO _x reflects at the interface. Since these lights interfere and attenuate, the black matrix 32 looks dark when viewed from outside the anode substrate 31.

Since Cr / CrO _x is conductive,
An insulating layer 33 is formed on r / CrO _x and an anode conductor 34 is formed.
Is formed on it. That is, the insulating layer 33 is formed so as to cover the black matrix 32 and the anode substrate 31, and the anode conductor 34 is provided on the insulating layer 33. A phosphor layer 35 is provided on the anode conductor 34. A protective layer 36 is provided on the insulating layer 33 so as to cover the anode conductor 34.

The black matrix 32 of the present embodiment,
The thickness of / CrO _x is as thin as 1500 angstroms.
Therefore, the insulating layer 33 for smoothing the thickness may be thinner than the conventional one, and a thin insulating layer having sufficiently high film quality can be formed by a sputtering method or a CVD method. As a result, the insulation between the anode conductors 34 provided adjacently at an interval is at a level that does not cause any problem.

For example, when the interval is 30 μm and the applied voltage is 80
In the case of 0V, if SiO ₂ as the insulating layer 33 is formed to a thickness of about ₂ μm, the insulation between the adjacent anode conductors 34, 34 is ensured. In a conventional black matrix using an inorganic pigment, in order to cover the thickness of the black matrix, voids between the pigments, surface irregularities, etc., an insulating layer having a thickness of about 15 μm is formed by a low-melting glass capable of forming a thick film. Had formed. The light transmittance of the insulating layer at that time was about 90%. The light transmittance of the insulating layer 33 of the present example was increased by 98% to the extent that the film thickness was reduced. By this, FE
It was possible to reduce the decrease in the lighting luminance of D.

The present inventor has found that Cr / CrO _x has the property of increasing the reflectance by heat treatment.
As a result of the study, this is because the heat treatment oxidizes the Cr layer on the surface side (upper side) to CrO _x , and the two-layer structure changes to a one-layer structure, and the antireflection effect cannot be obtained. Conceivable.

Table 1 below shows the relationship between the reflectance of the black matrix and the heat treatment temperature. As can be seen from the data in this table, if the firing temperature of the phosphor layer is set at 520 ° C. or less in the manufacture of the FED, the increase in reflectance can be suppressed to twice or less as compared with the case without heat treatment.

[0029]

[Table 1]

[0030]

(Embodiment 1) The FE in the first embodiment will be described below.
The manufacturing process of D will be described. Numbers in parentheses indicating items in the description of the first embodiment correspond to the numbers in parentheses of the division numbers in FIGS. 1 to 3.

(1) Cr / Cr used as a liquid crystal black matrix on a glass anode substrate 31
The O _X 42 is deposited. The anode substrate 31 side is a CrO _X layer, on which a Cr layer is formed.

(2) A resist 40 (15 cP) is applied at 3000 rpm / 2 s by a spin coating method, and is prebaked at 110 ° C./90 s using a hot plate.

(3) Ultraviolet irradiation is performed through the photomask 41 by an ultraviolet irradiation device. 80-500 mJ / cm of the resist 40 other than the portion where the black matrix is formed
To exposure in ^two of the ultraviolet rays.

(4) The exposed photoresist 40 is removed by immersion in a developing solution. After rinsing with pure water, post-baking is performed at 140 ° C./5 min using a hot plate.

(5) The anode substrate 31 is made of Cr / CrO _X
Cr / CrO _x 42 not coated with the resist is eroded and removed by immersion in a ceric ammonium nitrate solution as an etchant solution for 1 to 2 minutes.

(6) The anode substrate 31 is placed in a stripper for 10 minutes.
After being immersed to remove all the resist 40, it is cleaned by an arbitrary cleaning process.

(7) In order to provide the ITO wiring on the Cr / CrO _x 42 (black matrix 32), the insulating layer 33
10000 angstrom thick SiO _x 43
Is formed twice by a sputtering method to a total thickness of 20,000 Å. By forming the insulating layer 33 in a two-layer structure, the capacitance is higher than that of a single-layer structure having the same thickness.
It is reduced from 7 nF to 4 nF between the ED anode conductors, and the withstand voltage is improved about 1.5 times. As a result, the film thickness can be reduced to about 2/3 that of a single layer.

(8) The anode conductor 34 of ITO 44, which is a transparent conductive film, is formed to a thickness of 1500 angstroms by sputtering.

(9) A resist 40 (15 cP) is coated by a spin coating method at 3000 rpm / 2 s, and prebaked at 110 ° C./90 s using a hot plate.

(10) Ultraviolet irradiation is performed through the photomask 45 by an ultraviolet irradiation device. Anode conductor 3 of ITO44
The portion other than the portion where No. 4 is formed is exposed to ultraviolet light of 80 to 500 mJ / cm ² .

(11) The photoresist 40 exposed by immersion in a developing solution is removed. After rinsing with pure water, post-baking is performed at 140 ° C./5 min using a hot plate.

(12) ITO etching solution (oxalic acid)
At a temperature of 60 ° C. for 4.5 minutes to erode and remove ITO 44 at locations not covered with the resist 40.

(13) The anode substrate 31 is
After immersion for 0 min to remove all the resists 40, cleaning is performed by an arbitrary cleaning process.

(14) The protective layer 36 is made of S
A film of iO _x and SiN is formed.

(15) On the protective layer 36, a resist 40 (1
5cP) is applied at 3000 rpm / 2s by a spin coating method, and prebaked at 110 ° C / 90s using a hot plate.

(16) Ultraviolet irradiation is performed through a photomask 46 by an ultraviolet irradiation device. The portion other than the portion where the protective layer 36 is formed is exposed to ultraviolet light of 80 to 500 mJ / cm ² .

(17) The photoresist 40 exposed by immersion in a developing solution is removed. After rinsing with pure water, post-baking is performed at 140 ° C./5 min using a hot plate.

(18) Using RIE, resist 40
The portions of the protective film 36 that are not covered by the etching are removed by etching.

(19) The anode substrate 31 is set to 10 mi
After immersion for n times to remove all the resists 40, cleaning is performed by an arbitrary cleaning process.

(20) A photosensitive phosphor coating solution based on PVA is formed and patterned. The phosphor layer 35 is formed by firing at 520 ° C. Firing temperature 500 ~ 52
The reason why the temperature was set to 0 ° C. was that the sublimation temperature of the photosensitive material PVA used in the photosensitive phosphor coating solution was 500 ° C. or higher,
/ Firing the CrO _x at 520 ° C. or more, the Cr / CrO _X
This is because the light interference effect decreases and reflection increases. Thus, the FED anode substrate 31 having the black matrix 32 is completed.

(Example 2) Since the internal stress of the film formed by the sputtering method is large, cracks may be caused when the film is made thick. Therefore, C with smaller internal stress
An insulating layer on Cr / CrO _x was formed by the VD method.

1) Steps (1) to (6) of the first embodiment are performed. 2) Convert 10,000 _x angstrom thick SiO _x to CV
Formed by method D. Perform this operation twice, for a total of 2000
A SiO _x film having a thickness of 0 Å is formed. Thereafter, cleaning is performed by an optional cleaning process. 3) The steps (8) to (21) of Example 1 are performed to complete the FED anode substrate 31 having the black matrix 32.

(Embodiment 3) The sputtering method is less susceptible to the influence of the underlayer state than the CVD method.
O _X to first base processing alms using a sputtering method,
Then, an insulating layer was formed by a CVD method with small internal stress.

1) Steps (1) to (6) of the first embodiment are performed. 2) A film of SiO _{x is formed} to a thickness of 2000 Å by a sputtering method. 3) twice by a CVD method, the SiO _X 10000 angstroms, is deposited twice. Therefore, the total is 20,000 angstroms. Thereafter, cleaning is performed by an optional cleaning process. 4) By performing (8) to (21) of Example 1, the FED anode substrate 31 having the black matrix 32 is completed.

In each of the embodiments described above, Cr / CrO
_Although it had a black matrix consisting of _x , it consisted of two layers of metal and metal oxide, and the light reflected at the interface between the metal oxide and the substrate and the light reflected at the interface between the metal and the metal oxide interfered Other materials may be used as long as an antireflection effect can be obtained. For example, the same effect even Ni / NiO _X is obtained. The embodiment in which Ni / NiO _X is used for the black matrix 32 conforms to the case of Cr / CrO _x .

In each of the embodiments described above, SiO 2
_{Although the} insulating layer made of ₂ was used, another Si compound may be used. For example, the same effect can be obtained with SiN or SiON. The embodiment in which SiN or SiON is used for the insulating layer 33 conforms to the case of SiO ₂ .

Further, in each of the embodiments described above, PVA
The sintering temperature of the phosphor layer 35 was set to 500 ° C. or higher using a photosensitive phosphor coating solution based on Absent. Therefore, it is possible to change to a photosensitive phosphor coating solution based on another substance, and accordingly, the firing temperature of the phosphor layer 35 can be changed. For example, if a photosensitive phosphor coating solution based on an acrylic resin or ethyl cellulose is used, the baking temperature is 350 ° C. (preferably 400 ° C.) since the sublimation temperature of the acrylic resin or ethyl cellulose is 350 ° C. or higher.
520 ° C. is also possible.

In each of the embodiments described above, the FED is described as an example of a light emitting element having a black matrix. However, the present invention can be applied to a light emitting element other than the FED such as a fluorescent display tube or a plasma display panel. It is.

[0059]

According to the present invention, two kinds of metals and metal oxides are used.
A black matrix consisting of layers is provided, and this is covered with an insulating layer formed a plurality of times, and the temperature is controlled so that the metal layer does not oxidize and the reflectance of the black matrix does not increase when the phosphor is fired. ing. Therefore, the following effects can be obtained.

Since a black matrix having a low reflectance can be formed, the contrast of a displayed image is improved.

The black matrix is a conductive layer having a two-layer structure of a metal layer such as Cr / CrO _x and a metal oxide layer. The insulation is improved. Further, the thickness of the insulating layer covering the black matrix can be reduced, which is useful for reducing the size and weight of the entire display element.

Since the insulating layer was thin, the light transmittance of the insulating layer was improved, and the display luminance by the phosphor layer was improved.

Since the capacitance between the anode conductors is reduced, the reactive current is reduced, which leads to a reduction in power consumption and an improvement in response speed.

[Brief description of the drawings]

FIG. 1 is a process chart of Example 1 of the present invention.

FIG. 2 is a process chart of Example 1 of the present invention.

FIG. 3 is a process chart of Example 1 of the present invention.

FIG. 4 is a perspective view showing an example of the structure of a general FED.

FIG. 5 is a cross-sectional view showing an example of a structure of an anode substrate in a general FED.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 31 Anode substrate 32 Black matrix 33 Insulating layer 34 Anode conductor 35 Phosphor layer 42 Cr / CrO _X 43 which is a metal layer and a metal oxide layer SiO _X 44 as an insulating layer ITO constituting an anode conductor

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Yuji Nomura 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. F-term (reference) 5C028 JJ02 JJ09 5C036 EE01 EE05 EE19 EF01 EF06 EF08 EG02 EG24 EH04

Claims (11)

[Claims] 1. A black matrix formed on an inner surface of an anode substrate forming a part of an envelope and comprising a metal oxide layer on the anode substrate side and a metal layer formed thereon. The light emitting device according to claim 1, wherein the black matrix is fired at a predetermined temperature at which a reflectance of the black matrix is equal to or less than a predetermined value. 2. The light emitting device according to claim 1, wherein the predetermined temperature is 520 ° C. or lower. 3. The light emitting device according to claim 1, wherein the light emitting element includes the anode substrate having a phosphor layer, and the anode substrate is fired at a predetermined temperature higher than a temperature required for firing the phosphor layer. 2. The light emitting device according to 1. 4. The black matrix comprises a Cr layer and a C layer.
2. The light emitting device according to claim 1, comprising two layers of rO _X layers or two layers of Ni layers and NiO _X layers. 5. A black matrix formed on an inner surface of an anode substrate constituting a part of an envelope and comprising two layers of a metal oxide layer on the anode substrate side and a metal layer formed thereon. A light-emitting element having an insulating layer covering the black matrix, wherein the insulating layer is formed of the same insulating substance formed in a plurality of times. 6. The insulating layer according to claim 1, wherein said insulating layer has a thickness of 1 μm or more.
6. The light emitting device according to claim 5, comprising two layers of O ₂ , SiN or SiON. 7. A black matrix formed on an inner surface of an anode substrate constituting a part of an envelope and comprising a metal oxide layer on the anode substrate side and a metal layer formed thereon. A method for manufacturing a light emitting device, comprising: firing at a predetermined temperature at which the reflectance of the black matrix is equal to or less than a predetermined value. 8. The baking of the black matrix is performed by 52
The method according to claim 7, wherein the method is performed at a temperature of 0 ° C. or less. 9. The method according to claim 7, wherein the light emitting element has the anode substrate having a phosphor layer, and the anode substrate is fired at a predetermined temperature higher than a temperature required for firing the phosphor layer. A method for manufacturing the light-emitting element according to the above. 10. The method according to claim 7, wherein the black matrix is formed from two layers of a Cr layer and a CrO _X layer or two layers of a Ni layer and a NiO _X layer. 11. A black matrix formed on an inner surface of an anode substrate forming a part of an envelope and comprising a metal oxide layer on the anode substrate side and a metal layer formed thereon. A method for manufacturing a light-emitting element having an insulating layer covering the black matrix, wherein the insulating layer is formed of the same insulating substance in a plurality of times.