JP2005298951A - Method for manufacturing metallic member for picture display unit, and metallic member for picture display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a metallic member for a picture display unit, which secures an open area rate of the member even when spacing (hole pitch) between discharge spaces (cells) is narrowed, shows superior luminance and the superior definition of a panel even in an upsized picture display unit and has the superior accuracy of dimension, and to provide the metallic member for the picture display unit. <P>SOLUTION: The method for manufacturing the metallic member for the picture display unit, which has holes corresponding to picture elements of the picture display unit, comprises the steps of: forming holes in a metallic substrate by irradiation with thermal energy; and etching the formed holes. Preferably, the above thermal energy is an electron beam, and further preferably, an aspect ratio (height/width of web) of a frame between the nearest-neighbor holes is 4 to 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device such as a partition or a spacer partitioning a space corresponding to a pixel in an image display device such as a plasma display (hereinafter abbreviated as PDP), a field emission display (hereinafter abbreviated as FED), a liquid crystal display, or a sheet display. The present invention relates to a metal member manufacturing method and a metal member for an image display device.

For example, in a PDP that is a gas discharge type image display device, conventionally, a discharge space (cell) corresponding to a pixel is formed between two glass plates of a front plate and a back plate, and discharge between adjacent cells is performed. A glass partition is formed as a partition for preventing interference of light emission.
Similarly, in the FED, a spacer for securing a space and partitioning the cells is required between the front plate and the back plate.
In these new generation image display devices, there is a tendency for higher image quality and higher definition, and in the future, finer processing technology will be required for the partition walls and spacers. Finely partitioning the space with the partition walls directly leads to high definition of an image displayed on the image display device, and therefore, a fine deep hole processing technique is one of important techniques.
Particularly in the PDP, the performance largely depends on the structure of the cell. For high definition and high brightness, the aperture ratio of the cell can be increased by reducing the width of the partition wall that separates the cells. It is effective to widen the discharge space or increase the phosphor coating area by forming cells.

The glass barrier rib is formed by applying a paste-like barrier rib material on the back plate and then forming a discharge space by forming a groove or a hole mainly by a sandblasting method.
However, because of the low-temperature firing of the partition walls, this glass paste contains about 50% lead oxide. About 60% of the glass paste is dug by sandblasting and discarded together with the blasting material. In addition, there is a problem that the burden on the human body and the environment is large. Further, since the glass partition walls are fragile, chipping may be easily caused by sandblasting, and it is difficult to process the width of the partition walls separating the cells from each other and to perform deep hole processing to form high partition walls.

In order to solve the above-mentioned problem, Japanese Patent Laid-Open No. 3-205738 (see Patent Document 1) proposes a metal partition wall on which a dielectric material containing glass is formed by an electrodeposition method. The present inventors have also proposed a metal barrier in which a glassy insulating layer is formed on a metal material by ion plating in Japanese Patent Application Laid-Open No. 2000-3675 (see Patent Document 2).
Further, as described above, as a trend of new generation image display devices such as PDP and FED, higher definition is desired more and more, so fine hole drilling technology is a common requirement.
In response to this requirement, in particular, for the purpose of improving the brightness of an image display device, Japanese Patent Application Laid-Open No. 2003-168372 (see Patent Document 3) discloses a method in which a plurality of thin metal plates having through holes are laminated and thermocompression bonded. A method for increasing the height has been proposed. In addition, the present inventors also proposed a method in JP-A 2000-164144 (see Patent Document 4) in which a plurality of thin metal plates having through holes are stacked and heated and bonded to increase the height of the partition walls. doing.

Japanese Patent Laid-Open No. 3-205738 JP 2000-3675 A JP 2003-168372 A JP 2000-164144 A

In the metal barrier for PDP disclosed in Patent Document 1 and Patent Document 2, an insulating layer is separately required for the purpose of not exposing the metal member to the discharge space, but the metal barrier is stronger than the glass barrier and is a photoetching method. Since the barrier ribs can be formed by the processing according to the above, there are many advantages over the glass barrier ribs, such as fine processing with deep holes.
There is a demand to form deeper holes for the purpose of higher efficiency. However, photoetching has limitations in deep hole processing, and the aspect ratio of the crosspieces that form cells corresponding to pixels (crosspiece heights) There was a problem that it was difficult to increase the width / width. That is, in photo-etching processing, if the processing time is increased to form a deep hole, side etching (a phenomenon in which the etching hole tends to spread in the plane direction of the substrate) causes a masking with a resist. Until the hole diameter increases, there is a problem that processing accuracy is lowered.

The metal partition for an image display device disclosed in Patent Document 3 and Patent Document 4 is effective as a processing technique for a metal member having a high partition, that is, a deep hole, but requires a process of stacking and joining. In addition, man-hours and costs are required, and there is a possibility that the dimensions of the members may be distorted due to misalignment during joining or distortion caused by heating, which is a serious problem particularly in an image display device characterized by a large screen display.
In view of the above problems, the object of the present invention is to ensure the aperture ratio in the substrate even if the interval between the discharge spaces (cells), that is, the hole pitch is reduced, and the brightness and the definition of the panel even if the display is enlarged. An object of the present invention is to provide a method for producing a metal member for an image display device and a member for an image display device which are excellent and have excellent dimensional accuracy of the members.

In order to improve the performance and resolution of an image display device, the present inventor preferably forms a hole corresponding to a pixel finely and deeply, so that a deep hole is formed in a metal substrate. A method of forming finely, that is, a method of increasing the aspect ratio (crosspiece height / crosspiece width) of the crosspieces between the hole portions has been earnestly studied, and the present invention has been achieved.
The present invention relates to a method of manufacturing a metal member having a hole corresponding to a pixel of an image display device, the step of drilling by irradiating a metal substrate with thermal energy, and the step of performing etching after the hole processing The manufacturing method of the metal member for image display apparatuses containing this.

Preferably, the thermal energy irradiation is an electron beam manufacturing method of a metal member for an image display device.
More preferably, the hole portion is a method for manufacturing a metal member for an image display device, wherein an aspect ratio (bar height / bar width) between the nearest hole portions is 4 or more and 20 or less.

Further, the present invention provides a metal member having a hole corresponding to a pixel in an image display device, the hole being formed by a hole processing by irradiating a metal substrate with thermal energy, and etching after the hole processing. It is the metal member for image display apparatuses formed by processing.
Preferably, the hole is a metal member for an image display device having an aspect ratio (bar height / bar width) between the nearest hole portions of 4 or more and 20 or less.
Preferably, the material of the metal substrate is a metal member for an image display device that is an Fe—Ni alloy containing Ni in a mass ratio of 38 to 55%.
More preferably, it is a metal member for an image display device in which an insulating layer is formed on the surface layer.

By applying the manufacturing method of the present invention to the image display member, it is possible to form a partition wall having a large aspect ratio of the crosspieces between the hole portions with deep holes as compared with processing by etching or the like. The larger the aspect ratio of the crosspiece, the narrower the crosspiece, and even if the hole pitch is reduced, the aperture ratio of the member can be increased, and improvement in brightness and definition of the panel can be expected. Even in the case of the same hole pitch, by applying the member obtained by the manufacturing method of the present invention, the discharge space is widened in the PDP, so that improvement in luminous efficiency and reduction in power consumption can be expected.
In addition, there is no concern about the displacement at the time of joining or distortion caused by heating, which is a concern in the method of laminating and joining metal substrates having through-holes, and is excellent in dimensional accuracy of members.

An important feature of the present invention is that a deep hole is formed in the manufacture of a metal member for an image display device having a hole corresponding to a pixel of the image display device, and the aspect ratio of the crosspiece of the nearest hole is increased. For this purpose, a hole drilling process by applying thermal energy is applied.
The present invention is described in detail below.

In the present invention, hole processing by irradiation of thermal energy is applied to manufacture of a metal member for an image display device having holes corresponding to pixels of the image display device.
Among the image display devices, for example, in the conventional technology of PDP, as described above, the glass partition walls are formed by the glass paste material and the sandblasting process. The present inventors have proposed a metal partition and a metal partition by photoetching as a means for solving the problems of the environmental burden and the ease of chipping of the glass partition and expecting various performance improvements.
However, new generation image display devices such as PDPs and FEDs are required to have higher definition images, and therefore, finer hole processing is required. When trying to form a deep hole with a fine cell pitch by photo etching processing, as described above, the hole spreads sideways by side etching, so there is a possibility that it will be connected to the adjacent hole, Naturally there is a limit.
In addition, as described above, the method of laminating a metal substrate having a through hole is effective as a processing technique for a metal member having a deep hole. In addition, there is a possibility that the dimensional accuracy of the member may be distorted due to a deviation at the time of joining or distortion caused by heating.

Therefore, if hole processing by irradiation of thermal energy is applied as a hole processing method on the metal substrate, it is deeper than that achieved by a single photoetching process (from both the front and back surfaces of the metal substrate). In addition, the aspect ratio of the crosspiece between the closest holes can be further increased.
In addition, the holes obtained by thermal energy irradiation do not have the side etching seen in photo-etching processing, and the processed parts are once melted and hardened by the thermal energy irradiation, so that the shape of the hole in the cross section can be excessively uneven. There is no. Therefore, the shape which can form more uniformly also the insulating layer and fluorescent substance formed in a hole part wall surface is obtained.
Among image display devices, for example, in FEDs and PDPs, if there are irregularities on the cell wall, electric field concentration may occur when the panel is driven, but the holes once melted and solidified have no excessive irregularities. Since it is smooth, there is no concentration of electric field, and it can be expected to improve the efficiency of discharge and reduce power consumption.

As a method of drilling holes, for example, a metal substrate cut into a predetermined size is placed on a stage, and the irradiation position on the substrate is moved while the thermal energy irradiation device is moved or the thermal energy is deflected. The method of forming holes by intermittently irradiating thermal energy while changing the temperature, or by placing one or more thermal energy irradiation devices on the metal substrate while placing the metal substrate on the stage. Hole processing can be performed by a method in which a hole is formed by intermittently irradiating a metal substrate with thermal energy at a position greater than or equal to a location.
In this case, the atmosphere (air, argon, nitrogen, hydrogen, etc.) and the degree of vacuum (atmospheric pressure, low vacuum, high vacuum) may be selected according to the type of thermal energy device.

In the present invention, the etching process performed after the hole process by the irradiation of the thermal energy is important. In the drilling by thermal energy irradiation, there is not a complete occurrence of burr-like projections due to reattachment of molten metal.
The present inventor has found that the burr-like protrusions thus generated can be removed with high accuracy by etching. Further, the etching process has an effect of removing the undissolved portion around the hole processed portion by irradiation of thermal energy.
Also, since the processing proceeds from the initial stage of etching from the inner wall of the hole processed by thermal energy irradiation, unlike the conventional photo-etching processing from the front and back sides, it is possible to perform excessive side etching in a short time. The effect of narrowing the crosspiece width between the hole portions without any problems can be expected. Therefore, the aperture ratio of the member is increased and high brightness can be expected. Of course, in this case, it is effective to design the size of the hole to be processed by irradiation of thermal energy in consideration of the etching processing conditions.
In addition, this etching process makes it possible to smooth the skin of the metal member, that is, to reduce the surface roughness, and as described above, it is more advantageous for uniform formation of the insulating layer and the phosphor layer, There is no concentration of the electric field, and it can be expected to be more effective in improving discharge efficiency and reducing power consumption.

In the present invention, the above-described hole portion may be a hole penetrating in the thickness direction of the substrate or a non-penetrating hole. Whether the hole is a through hole or a non-through hole depends on whether the metal member for an image display device of the present invention is used as a partition wall or a spacer, or a partition wall also having a rear substrate. A suitable hole shape may be selected depending on the combination with other members constituting the display device.
When assembling the panel for the image display device, the metal member for the image display device in which the through hole is formed requires not only the front plate glass but also glass or other back substrate on the back surface. It can be used as a partition or a spacer by joining so as to be sandwiched between the plates.
In the case of a metal member in which a non-through hole is formed, the metal member for an image display device of the present invention can also serve as the above-mentioned rear substrate, and therefore it is possible to assemble as a panel by joining only the front plate glass. is there. In this case, compared to the conventional glass back substrate, the member of the present invention is excellent in strength relative to the thickness, can contribute to the weight reduction of the panel, and excellent in thermal conductivity, so that improvement in heat dissipation is expected, More preferred.

Further, the material of the metal substrate is not particularly limited, but for example, it may be affected by heat of about 400 to 500 ° C. in the process of firing the phosphor or the assembly process of the image display device. As the front plate and the back plate, soda lime glass or high strain point glass having a thermal expansion coefficient (20 to 500 ° C.) of about 8 to 9 × 10 ⁻⁶ / ° C. is mainly used. It is desirable that the thermal expansion coefficient is ⁶ to 10 × 10 ⁻⁶ / ° C. which is close to the thermal expansion coefficient (20 to 500 ° C.) of glass. Preferred components will be described later.
In addition, about the thickness of a metal substrate, about 30 micrometers-1 mm are desirable. It is good to select according to the purpose to which the metal member for image display devices of the present invention is applied. When used as a spacer in an image display device characterized by being thin, it is desirable that the substrate is as thin as possible. For this, the substrate is desired to be higher than the current glass partition (about 100 to 130 μm), more preferably about 150 to 500 μm.

In the present invention, typical examples of the thermal energy irradiation include a laser and an electron beam. Processing with an electron beam is particularly preferable.
Usually, in a processing machine using a laser, the generated laser light is deflected by driving a galvano mirror having an axis, and is mechanically deflected, so that it is difficult to increase the processing speed. On the other hand, since the electron beam is electrically operated using an electromagnetic coil, the processing speed can be increased and the productivity can be increased, which is advantageous in manufacturing the member.

If the manufacturing method of the present invention is applied, the aspect ratio (crosspiece width / crosspiece height) that is difficult to achieve with one etching (from both the front and back sides of the metal substrate) with respect to the aspect ratio of the crosspiece between the nearest holes. ) 4 to 20 can be achieved.
And the crosspiece between the nearest holes referred to in the present invention is a hole that is processed on the substrate so as to correspond to a pixel, and exists between another hole that has the shortest distance from the center of the hole. Say the part of the pier. For example, in FIG. 2 (a), when viewed from the hole part A, the closest hole part is the hole part of A and C, and the crosspiece existing between these hole parts. . The hole part of D is not the closest, but is the second adjacent hole part, and the crosspieces between these hole parts are not targeted.
In the present invention, the crosspiece width means the crosspiece width with the upper base of the trapezoid when the cross-sectional shape of the crosspiece is not a rectangle but a trapezoid. That is, in the present invention, the aspect ratio is defined as H / A in FIG. Since the crosspiece is on the upper surface side of the substrate, that is, on the side close to the front plate glass, it is a portion related to the aperture ratio of the image display device.

With respect to the aspect ratio of the crosspiece, for example, in a PDP having a current glass partition, a partition having a trapezoidal cross section is formed by sandblasting. In this partition, the width of the upper part of the crosspiece is about 60 μm and the height of the partition is about 120 μm, so the aspect ratio is about 2. In addition, when drilling a metal substrate by photoetching, even if the spray pressure from the nozzle is increased and photoetching is performed from both the front and back surfaces of the metal substrate, the general cell hole width ( 100-300 μm) and crosspiece width (30-70 μm), side etching progresses, making it difficult to obtain a sufficient crosspiece height, and only an aspect ratio of less than 2-4 can be obtained. .
In order to obtain an aspect ratio of 4 or more, there is a method of laminating a substrate in which a through hole is formed. In particular, image display devices that feature large screen displays are a major problem.
In the present invention, an aspect ratio of 4 or more, which cannot be obtained by ordinary photoetching, can be obtained with only one metal plate without being laminated, so the lower limit of the aspect ratio is set to 4.
In the present invention, the upper limit of the aspect ratio is set to 20. However, even if a discharge cell that is deeper than necessary is formed, when it is assembled and driven as an image display device, the light is emitted at a place too far from the front glass. This is because it does not contribute to luminance from the viewpoint of the extraction efficiency.

Next, a preferable material for the metal substrate in the present invention will be described.
As described above, the thermal expansion coefficient of the high strain point glass used for the front plate or the back plate (20- It is desirable that it is ⁶ to 10 × 10 ⁻⁶ / ° C. close to 8 × 10 ⁻⁶ / ° C. of 500 ° C.).
Therefore, in the present invention, it is preferable to use an Fe—Ni alloy containing Ni in a mass ratio of 38 to 55%. For example, many image display devices such as FED spacers and PDP partition walls have high strain point glass. In the assembly process, since it is affected by heat of about 500 ° C., the thermal expansion coefficient (20 to 500 ° C.) of the high strain point glass used for the front plate and the back plate is 8 × 10. ^This is because it is an alloy that can easily approximate the thermal expansion characteristics by adjusting the Ni content to the thermal expansion characteristics of ⁶ to 10 × 10 ⁻⁶ / ° C. close to ⁻⁶ / ° C.
The Fe—Ni-based alloy in the present invention may contain inevitable impurities as long as the performance thereof is not impaired, and may additionally contain other elements according to desired properties. good. For example, an Fe—Ni—Cr alloy such as Fe-42Ni-6Cr partially substituted with Cr for the purpose of improving the bondability with glass or the like is also included.

In the present invention, an insulating layer may be formed on the surface layer of the metal substrate that has been subjected to hole machining as described above.
In the image display device, when a metal member is applied as a partition wall or a spacer, for example, an insulating layer is necessary for the purpose of not exposing the metal substrate to a space in which plasma exists in PDP and electrons exist in FED. It is.
As a method for forming the insulating layer, a method in which the insulating layer is formed by a highly efficient film formation method represented by a vapor deposition method is preferable.
The thickness of the insulating layer may be set to a thickness suitable for the environment in which the member is installed so that dielectric breakdown does not occur due to the electric field applied to the member, and may be about 0.1 to 10 μm. The aperture ratio is preferably 5 μm or less so as not to unnecessarily reduce the aperture ratio. As the insulating layer, an oxide such as SiO ₂ or Al ₂ O ₃ that is generally used industrially may be formed.
In addition, in an image display device, when applied as a member that is required to have excellent reflection characteristics, crystallized glass is selected as the insulating layer, for example, a film is formed by vapor deposition, phase separation or Crystallization should improve the reflection characteristics.
Needless to say, the insulating layer may be formed after the holed metal substrate is joined to another member.

The metal member for an image display device obtained as described above can ensure the aperture ratio in the member even when the hole pitch is reduced, and improve the brightness and the definition of the panel, in order to increase the definition of the image display device. Can be expected. In particular, when used as a PDP barrier rib, the aperture ratio is larger than that of the barrier rib having the same hole pitch obtained by a single photoetching process, so that improvement in luminance can be expected and the discharge space becomes wide. Improvement in luminous efficiency and reduction in power consumption can be expected.
In addition, there is no concern about misalignment at the time of joining or distortion caused by heating, which is a concern in the method of laminating metal substrates having through-holes, excellent dimensional accuracy of members, and low current used for glass partition walls and green sheets. Since melting point glass is not used, it has the advantages that it does not contain harmful lead and does not cause environmental problems.

Hereinafter, the present invention will be described in more detail with reference to examples.
A 48 mass% Ni—Fe alloy with a thermal expansion coefficient of 8.5 × 10 ⁻⁶ / ° C. was vacuum-melted, homogenized, heat forged, hot rolled, and repeatedly subjected to cold rolling and annealing to a plate thickness of 410 μm. A material obtained by cutting the rolled cold rolled material into approximately the same size as the panel was used as a metal substrate so that it could be applied to a metal partition wall for PDP, which is one of the metal members for an image display device.
By placing the metal substrate on the stage of the processing machine and moving the stage while intermittently irradiating an electron beam, which is one of the thermal energy irradiations, the hole pitch corresponding to the pixel of the PDP (the horizontal direction is 350 μm, A hole portion of 700 μm in the vertical direction was formed, and used as a material for a metal member for an image display device having a through hole as shown in FIG.
In the material of the metal member for the image display device, the cross-sectional shape of the crosspiece between the closest holes was a bell shape as shown in FIG.

Etching is performed on the material of the metal member for the image display device that has been subjected to the hole processing using an etching solution mainly composed of ferric chloride, and smooth skin is obtained as shown in FIG. It was set as the metal member for image display apparatuses which has. This etching process is not a photo-etching process using a resist, but only an etching solution is sprayed on the material of the metal member for an image display device that has been subjected to hole processing.
In order to measure the aspect ratio of the crosspiece between the closest hole portion from the substantially central portion of the metal member for the image display device, a test piece was cut out. This cross section was a triangle as shown in FIG. In order to join the front plate with the same height, the surface of the metal substrate (from the upper side to the broken line in the figure) is mechanically polished to a height of 250 μm. The ratio was 5.0.
Similarly, for the material of the metal member for an image display device subjected to hole processing, when the etching processing time is shortened and the height after polishing is 370 μm, the upper base is 63 μm, and the aspect ratio is 5.9. It was.

In addition, as a comparative example, an attempt was made to process the same shape using a cold rolled material having a plate thickness of 410 μm as a metal substrate by a single photoetching process. Etching connected adjacent holes, making it impossible to produce a metal member for an image display device having a desired shape.
Therefore, in order to obtain a plate thickness that allows through-hole processing, the above-mentioned cold-rolled material having a thickness of 200 μm is obtained by further annealing and cold-rolling the cold-rolled material having a thickness of 410 μm. Through holes were formed as a metal substrate by photoetching. The aspect ratio of the crosspieces between the nearest holes was 3.7.
The measurement results of the dimensions of the present invention and the comparative example are shown in Table 1.

As described above, the hole corresponding to the pixel of the image display device is formed by the step of drilling by irradiation of thermal energy and the step of performing etching after the hole processing, and the hole of the closest proximity is formed. A member having an aspect ratio (crosspiece width / crosspiece height) of 4 or more can be used.
Therefore, it is excellent in dimensional accuracy of the member, and has high brightness because of high definition and excellent aperture ratio. For example, when applied to a PDP, a member for an image display device having a wide discharge space and excellent luminous efficiency can be obtained.

On the metal member for an image display device of the present invention obtained as described above, an Al ₂ O ₃ oxide layer is formed with a thickness of 2 μm by sputtering, which is one of vapor phase film formation methods. As a member for an image display device, it is bonded to a back plate provided with wiring through a bonding layer, a phosphor layer is formed by a screen printing method, and further bonded to a front plate glass, thereby being one of the image display devices. It can be a panel of a certain PDP.

  According to the present invention, fine deep hole machining can be performed with high precision, and therefore, it is suitable for application to applications where through holes and non-through holes are formed and the accuracy of hole dimensions is required.

It is the external appearance photograph and cross-sectional photograph of the metal substrate which carried out the hole process by irradiation of a thermal energy. It is a schematic diagram which shows the aspect-ratio of this invention.

Claims (7)

A method for manufacturing a metal member having a hole corresponding to a pixel of an image display device, comprising a step of drilling a hole by irradiating a metal substrate with thermal energy, and a step of performing an etching process after the hole processing A method for producing a metal member for an image display device. The method of manufacturing a metal member for an image display device according to claim 1, wherein the thermal energy irradiation is an electron beam. 3. The metal member for an image display device according to claim 1, wherein the hole has an aspect ratio (bar height / bar width) between the closest holes of 4 or more and 20 or less. Manufacturing method. In the image display device, the metal member has a hole corresponding to a pixel, and the hole is formed by a hole processing by irradiation of heat energy to the metal substrate and an etching process after the hole processing. A metal member for an image display device. 5. The metal member for an image display device according to claim 4, wherein the hole has an aspect ratio (bar height / bar width) between the nearest holes of 4 or more and 20 or less. 6. The member for an image display device according to claim 4, wherein the material of the metal substrate is an Fe—Ni alloy containing Ni in a mass ratio of 38 to 55%. The metal member for an image display device according to any one of claims 4 to 6, wherein an insulating layer is formed on a surface layer.