JP2009259504A - Plane display member, plasma display panel, plane display device and plasma display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the generation of color irregularities and the lowering of contrast without requiring an optical filter. <P>SOLUTION: A chrome oxide layer 34 is formed as a part of a bus electrode 15 so as to come into contact with an ITO (indium tin oxide) layer which is a transparent electrode 14. The reflection of external light by a lower chrome layer 31 formed on the chrome oxide layer 34, and the reflection of external light by the chrome oxide layer 34 interfere with each other by the adjustment of the film thickness of this chrome oxide layer 34. As a result, reduction in the reflection of the external light is made possible, and the generation of the color irregularities and the lowering of the contrast can be prevented without depending on the optical filter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flat panel display member having an electrode on a front glass substrate, and more particularly to a means for suppressing reflection of external light from a plasma display panel.

  A plasma display device is one of large-screen display devices used for home use or business use in place of a display device using a cathode ray tube.

  The plasma display device is a flat display device that displays a front glass substrate as a display surface by using a display electrode pair provided on a front glass substrate and causing a phosphor provided on the rear substrate to emit light.

  To transmit light through the front glass substrate means that light (external light) emitted from an external light source also passes through the plasma display panel. As the external light enters, the electrodes formed on the front glass substrate reflect, causing problems such as occurrence of color unevenness and a decrease in contrast. In particular, the bus electrode was often metallic and had a high reflectivity.

  Conventionally, for these problems, it has been common to insert an optical filter in front of the plasma display panel to prevent reflection.

  However, inserting an optical filter over the entire display surface increases the cost of components as the size of the display surface increases.

  An object of the present invention is to prevent occurrence of color unevenness and reduction in contrast without requiring an optical filter.

  Another object of the present invention is to reduce the reflected light of the flat display member as much as possible while using an optical filter, thereby reducing the cost of the flat display device.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  A flat display member according to a typical embodiment of the present invention includes a front glass substrate and a rear glass substrate, and forms a discharge space for sealing a light emitter between the front glass substrate and the rear glass substrate. A bus electrode having a transparent electrode and a chromium oxide layer is formed on a surface facing the discharge space of the substrate, and the chromium oxide layer is configured to be in contact with the transparent electrode.

  In the flat display member, the bus electrode may be formed of a chromium oxide layer, a lower chromium layer, a copper layer, and an upper chromium layer in this order. Further, the chromium oxide layer may have a film thickness between 30 nm and 100 nm.

  In this flat display member, the bus electrode may include a chromium oxide layer, a copper layer, and an upper chromium layer. Further, the chromium oxide layer may have a film thickness between 100 nm and 150 nm.

  It is also within the scope of the present invention to construct a flat display device using these flat display members. It is also assumed that a filter is disposed in front of the display surface of the flat display device and that the target wavelength for reducing the reflectance of the display surface is 500 to 550 nm.

  A flat display member according to a typical embodiment of the present invention includes a front glass substrate and a rear glass substrate, and forms a discharge space for sealing a light emitter between the front glass substrate and the rear glass substrate. A bus electrode having a chromium oxide layer is formed on a surface facing the discharge space of the substrate, and the chromium oxide layer is configured to be in contact with the front glass substrate.

  The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

  The flat display member according to the representative embodiment of the present invention can reduce reflected light without adding a filter to the flat display device.

  In addition, the flat display member according to another embodiment of the present invention can reduce reflected light at low cost even when a filter of a conventional flat display device is used.

  A first embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is an exploded perspective view showing a configuration of a plasma display panel (flat display member) 100 used in a plasma display device (flat display device).

  The plasma display panel 100 is configured so as to be sandwiched between a front glass substrate side module 10 centering on the front glass substrate 1 and a rear glass substrate side module 20 constituting the rear glass substrate 21.

  The front glass substrate side module 10 includes a front glass substrate 1, a dielectric layer 2, a protective film layer 3, an X electrode 5, and a Y electrode 6. On the other hand, the back glass substrate side module 20 includes a back glass substrate 21, a base layer 22, a rib 23, a red phosphor 24, a green phosphor 25, a blue phosphor 26, and an address electrode 27.

  The front glass substrate 1 is a glass substrate used for sealing the constituent elements of the plasma display panel 100 with the rear glass substrate 21.

  The dielectric layer 2 is a transparent dielectric layer coated on the front glass substrate 1. After the X electrode 5 and the Y electrode 6 are configured, a low melting point glass layer is formed with a thickness of 20 microns.

  The protective film layer 3 is an insulating protective film for preventing the dielectric layer 2 from being damaged by a discharge phenomenon. It is created by forming a layer of a protective film material (magnesium oxide, scandium oxide, calcium oxide, barium oxide, etc.) by 1 micron by vacuum deposition.

  The X electrode 5 and the Y electrode 6 are applied to the front glass substrate 1 and the rear glass substrate by applying a voltage between the X electrode 5 and the Y electrode 6 after the preliminary discharge by the address electrode 27 provided on the rear glass substrate 21. 21 is a transparent electrode for causing plasma discharge of a rare gas such as xenon enclosed between 21. Each of these electrodes includes a transparent electrode 14 and a bus electrode 15. The discharge generated by the plasma excites and emits a phosphor (any one of the red phosphor 24, the green phosphor 25, and the blue phosphor 26).

  The rear glass substrate 21 is a glass substrate used for sealing the components of the plasma display panel 100 between the rear glass substrate 1 and the front glass substrate 1.

  The underlayer 22 is a dielectric layer for protecting the address electrodes 27 in the configuration of the ribs 23 and the like.

  The rib 23 is a partition for sealing a rare gas that causes plasma discharge. A space (discharge space) partitioned by this, the front glass substrate side module 10 and the rear glass substrate 21 is filled with a discharge gas.

  The red phosphor 24 is a phosphor that emits red light when excited by plasma generated by voltage application to the X electrode 5, the Y electrode 6, and the address electrode 27. Mainly yttrium compounds are used.

  The green phosphor 25 is a phosphor that emits green light by ultraviolet excitation by plasma. As the green phosphor 25, a green silicate phosphor is used.

  The blue phosphor 26 is a phosphor that emits blue light by ultraviolet excitation by plasma. As the blue phosphor 26, a blue aluminate-based phosphor is used.

  The address electrode 27 is an electrode that performs preliminary discharge for plasma discharge.

  These front glass substrate side module 10 and back glass substrate side module 20 are combined, and the periphery is sealed with low melting glass. After sealing, the inside of the panel is evacuated to a temperature and degassed. Thereafter, the plasma display panel 100 is produced by enclosing a discharge gas (xenon 10% + neon 90%) inside the panel.

  One of the electrode formations of the X electrode 5 and the Y electrode 6 formed on the front glass substrate 1 is ITO (Indium Tin Oxide) and Cr / Cu / Cr (chromium / copper / chromium). FIG. 2 is a schematic diagram showing the structure of a conventional X electrode 5 and Y electrode 6.

  Indium tin oxide constituting the transparent electrode 14 is conductive and transparent. On the other hand, the chromium layer (lower chrome layer) 31 close to ITO of Cr / Cu / Cr constituting the bus electrode 15 has the purpose of ensuring adhesion with the glass substrate. The copper layer 32 is configured for the purpose of reducing the wiring resistance of the bus electrode. The upper chrome layer (upper chrome layer) 33 is formed to ensure adhesion of the dielectric layer 2.

  When the plasma display panel 100 is used, each color phosphor emits light through the front glass substrate 1. Conversely, light from the outside hits the chrome layer 31 of the bus electrode 15 via the glass substrate and is reflected.

  The external light hitting the chromium layer 31 is reflected and enters the eyes of the user of the plasma display device. It is known that this reflected light affects the unevenness and contrast of the display surface of the plasma display panel.

  FIG. 3 is a graph showing the measurement results of the reflectance of chromium and copper. The conditions for this evaluation were vapor deposition on glass having a thickness of 2.8 mm (transmittance of the glass: 84%), and a D65 light source was used as the light source.

  In this evaluation, the reflectivity of chromium in the visible light region is approximately 50%. Although this is a good property compared to copper which has a large reflection at 550 nm or more (green to red wavelength), it can be seen that it still reflects 50% of light.

  FIG. 4 is a schematic diagram showing the structures of the X electrode 5 and the Y electrode 6 in the first embodiment of the present invention.

  In the configuration of FIG. 4 of the present invention, ITO is first formed on the front glass substrate 1. This ITO becomes the transparent electrode 14. Thereafter, a chromium oxide layer 34 is formed on the ITO by vapor deposition. Further, a chromium layer 31, a copper layer 32, and a chromium layer 33 are formed from above the chromium oxide layer 34. The chromium oxide layer 34, the chromium layer 31, the copper layer 32, and the chromium layer 33 constitute the bus electrode 15.

  The chromium oxide layer (metal oxide layer) 34 is an insulating film. However, since an alternating voltage is applied to the X electrode 5 and the Y electrode 6 during driving, the transparent electrode 14 and the bus electrode 15 sandwiching the chromium oxide layer 34 are capacitively coupled. Therefore, the presence of the chromium oxide layer 34 does not affect the driving.

  By adopting such a structure, the reflection of the chromium oxide layer 34 and the reflection of the chromium layer 31 interfere with each other, and the reflectance is reduced. FIG. 5 is a conceptual diagram of mutual interference between the reflected lights.

  In order to reduce the reflectance, it is necessary to make the thickness of the chromium oxide layer 34 appropriate. The calculation formula at this time is as the formula (1).

d = (λ / ng) / 4n (1)
Here, λ is the wavelength, n is the refractive index of the chromium oxide layer 34, ng is the refractive index of the front glass substrate, and d is the film thickness.

  It is assumed that the refractive index of chromium oxide is 2.5, the refractive index of the front glass substrate is 1.5, and the wavelength for reducing the reflectance is 550 nm. A film thickness d of about 37 nm can be derived. This is the thickness of the chromium oxide layer 34.

  FIG. 6 is a graph showing the reflectance when each electrode with this chromium oxide layer 34 is formed. As is apparent from this graph, it can be seen that the reflectance can be reduced to 6% or less near 550 nm and 15% or less even at other wavelengths of visible light. In the actual film formation process, the thickness of the chromium oxide layer 34 varies. However, if this thickness is 30 mm to 65 mm, the effect of FIG. 6 is almost obtained.

  The chromium oxide film preferably has a refractive index of 1.9 to 2.5 and a transmittance of 65% or less in a region where the wavelength is 550 nm. The refractive index of the chromium oxide film depends on the amount of oxygen determined by the deposition conditions. The larger the amount of oxygen, the lower the refractive index, and the smaller the amount of oxygen, the higher the refractive index. The reason why the refractive index is set to 1.9 to 2.5 is that when the refractive index is 2.5 or more, the reflectance is too high, and when it is 1.9 or less, the resistance as a film is lowered. The reason why the wavelength region of 550 nm is used as a reference is that the visual sensitivity of the human eye is the highest.

  The refractive index of the chromium oxide film is a numerical value when the underlying layer is copper, and is 2.1 to 2.7 when the underlying layer is chromium.

Thus, the effect of forming the chromium oxide layer 34 is great. On the other hand, an additional film forming step is required. For the formation of the chromium oxide layer 34, PureCr reactive sputtering is used. When the reactive sputtering method is used, it is formed by introducing O ₂ into argon (Ar) gas or using a mixed gas of CO ₂ and N ₂ .

  Heretofore, the description has been made assuming that the chromium oxide layer is formed on the ITO, but the chromium oxide layer 34 may be formed directly on the front glass substrate 1.

  As described above, the reflectance can be reduced by inserting the chromium oxide layer, and it is possible to contribute to reduction of unevenness of the display surface of the plasma display panel and improvement of contrast.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.

  FIG. 7 is a schematic diagram showing the structure of the X electrode 5 and the Y electrode 6 according to the second embodiment of the present invention. FIG. 8 is a graph showing the reflectance when each electrode having the configuration of FIG. 7 is formed. In the measurement of FIG. 8, 1) chromium oxide film / copper / chromium: chromium oxide film thickness 60 nm, 2) chromium oxide film / copper / chromium: chromium oxide film thickness 120 nm, 3) chromium oxide film / chromium / Three of copper / chromium: chromium oxide film thickness 60 nm were measured.

  In the second embodiment, a configuration in which the chromium layer 31 is omitted and the copper layer 32 is directly provided on the chromium oxide layer 34 is adopted.

  As shown in FIG. 3, the reflection characteristics of copper increase at 550 nm or more (green to red wavelength). Therefore, when the copper layer 32 is provided directly on the chromium oxide layer 34 as shown in FIG. 7, it can be seen that the chromium oxide layer 34 does not contribute to reflection with a wavelength of 550 nm or more, as can be seen in FIG. This is because there is no mutual interference of the wavelengths of reflected light in each phase in FIG. As can be seen from this, the reflection characteristic of the configuration of the second embodiment is inferior to the configuration of the first embodiment.

  When the film thickness of chromium oxide is changed, the reflected light is green at a film thickness of 60 nm, the reflected light is yellow at a film thickness of 90 nm, and red at 120 nm.

  Here, let us return to the configuration of the plasma display device.

  In a normal plasma display device, the display surface of the plasma display panel is rarely used as the display surface of the plasma display device. As described above, a filter is provided on the entire display surface of the plasma display panel to prevent unevenness due to reflected light and improvement of contrast. This embodiment is premised on the use in combination with this filter.

  FIG. 9 is a graph showing characteristics of a filter of a general plasma display device. As can be seen from this figure, the filter of the existing plasma display device is also designed with the reflected light of around 550 nm-600 nm in mind. Therefore, measures are taken for the vicinity of 550 nm as long as the filter is used.

  FIG. 10 is a graph in which the reflectance is measured again by combining each electrode used in the measurement of FIG. 8 with an existing filter. As can be seen from this, when the film thickness of the chromium oxide film 34 is set to 120 nm, from the low wavelength to the high visual sensitivity of 600 nm, the same performance as that of the chromium oxide film / chromium / copper / chromium is shown. Yes. As in the first embodiment, the thickness of the chromium oxide film 34 may vary in the actual film formation process. However, if the thickness is 100 nm to 150 nm, the desired performance can be exhibited. Is possible. As described above, even if the chrome layer 31 is omitted and the process is simplified, it is possible to contribute to reduction of unevenness of the display surface of the plasma display panel and improvement of contrast. As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

  In the above description, the description is limited to the plasma display panel, but is not necessarily limited thereto. That is, the present invention can be applied to any display device that attaches wiring to the glass substrate on the display surface side.

It is a disassembled perspective view which shows the structure of the plasma display panel used for a plasma display apparatus. It is a schematic diagram showing the structure of the conventional X electrode and Y electrode. It is a graph showing the measurement result of the reflectance of chromium and copper. It is a schematic diagram showing each electrode structure in a 1st embodiment. It is a conceptual diagram of mutual interference between reflected lights. It is a graph showing the reflectance at the time of forming each electrode with the chromium oxide layer in 1st Embodiment. It is a schematic diagram showing the structure of each electrode in connection with 2nd Embodiment. It is a graph showing the reflectance at the time of forming each electrode in connection with 2nd Embodiment. It is a graph showing the characteristic of the filter of a general plasma display apparatus. It is the graph which measured the reflectance, combining each electrode used by the measurement of FIG. 8, and the filter of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Front glass substrate, 2 ... Dielectric layer, 3 ... Protective film layer,
5 ... X electrode, 6 ... Y electrode, 10 ... front glass substrate side module,
14 ... transparent electrode, 15 ... bus electrode,
20 ... Back glass substrate side module, 21 ... Back glass substrate, 22 ... Underlayer,
23 ... Ribs, 24 ... Red phosphor, 25 ... Green phosphor, 26 ... Blue phosphor,
27: Address electrode, 100: Plasma display panel.

Claims (15)

A plasma display panel comprising a front substrate and a rear substrate,
A transparent electrode formed on the front substrate, and a bus electrode having a chromium oxide layer,
The thickness of the chromium oxide layer is such that the first reflected light reflected on the front side of the chromium oxide layer interferes with the second reflected light reflected on the back side of the chromium oxide layer. A plasma display panel characterized by The plasma display panel according to claim 1, wherein
When the bending rate of the chromium oxide layer is n, the refractive index of the front substrate is ng, the thickness of the chromium oxide layer is d, and the wavelength of incident light is λ, the relationship is d = (λ / ng) / 4n. A plasma display panel characterized by satisfying. The plasma display panel according to claim 1, wherein
The said bus electrode is equipped with the said chromium oxide layer, a 1st chromium layer, a copper layer, and a 2nd chromium layer from the front side toward a plane side, The plasma display panel characterized by the above-mentioned. A flat display member comprising a front glass substrate and a rear glass substrate, and constituting a discharge space for sealing a light emitter between the front glass substrate and the rear glass substrate,
A bus electrode having a chromium oxide layer is formed on a surface of the front glass substrate facing the discharge space,
The chromium oxide layer has a refractive index of 1.9 to 2.7 and a transmittance of 65% or less in a wavelength region of 550 nm, and is in contact with the transparent electrode formed on the front glass substrate or the front glass substrate. A flat display member comprising:   5. The flat display member according to claim 4, wherein the bus electrode is configured in the order of the chromium oxide layer, the lower chromium layer, the copper layer, and the upper chromium layer.   6. The flat display member according to claim 5, wherein the chromium oxide layer has a refractive index of 2.1 to 2.7 and a transmittance of 65% or less in a wavelength 550 nm region.   6. The flat display member according to claim 5, wherein the chromium oxide layer has a thickness of 30 nm to 100 nm.   5. The flat display member according to claim 4, wherein the bus electrode includes the chromium oxide layer, a copper layer, and an upper chromium layer.   9. The flat display member according to claim 8, wherein the chromium oxide layer has a refractive index of 1.9 to 2.5 and a transmittance of 60% or less in a wavelength region of 550 nm.   The flat display member according to claim 8, wherein a film pressure of the chromium oxide layer is between 100 nm and 150 nm.   A plasma display device using the plasma display panel according to claim 1.   A flat display device using the flat display member according to claim 4.   12. The plasma display device according to claim 11, further comprising a filter in front of an externally exposed surface of the plasma display panel.   12. The plasma display device according to claim 11, wherein a wavelength for reducing the reflectance of the display surface of the plasma display panel is 500 nm to 550 nm. A flat display member comprising a front glass substrate and a rear glass substrate, and constituting a discharge space for sealing a light emitter between the front glass substrate and the rear glass substrate,
A bus electrode having a chromium oxide layer is formed on a surface of the front glass substrate facing the discharge space,
The flat display member, wherein the chromium oxide layer is formed in contact with the front glass substrate.

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