JP4586550B2 - Envelope for flat display and flat display using the same - Google Patents

Description

  The present invention relates to a flat panel display having a cold cathode type electron emission source, represented by a field emission display (hereinafter referred to as “FED”), and an envelope made of glass and a support member used therefor.

  In recent years, as a television broadcast receiver (hereinafter referred to as “TV”), a flat plate such as a liquid crystal display (hereinafter referred to as “LCD”) or a plasma display panel (hereinafter referred to as “PDP”) instead of a television using a cathode ray tube. There is an increasing demand for displays (flat panel displays; hereinafter referred to as “FPD”). An FED is known as an FPD other than the LCD and the PDP. The FED is characterized in that it consumes less power than a PDP, a cathode ray tube (hereinafter referred to as “CRT”) and an LCD, and has a high brightness and high definition compared to an LCD, etc., and a wide viewing angle. The spread to general households is expected.

  The FED is an image display device in which a very small emitter (cold cathode element) is arranged for each pixel, and an electron beam is emitted from the emitter toward the phosphor in a vacuum in the same manner as the CRT to form an image. Unlike the CRT, the FED in which the emitter is driven independently for each pixel does not need to scan the electron beam at a wide angle, so that it is much thinner than the CRT and can form a flat image display surface. For example, see JP-A-7-230776 (Patent Document 1).

  A conventional FED has a support structure that can withstand atmospheric pressure inside, and a plurality of spacers as gap holding members, a rear glass having a front glass coated with a phosphor, and an emitter for emitting electrons. Are joined via a substantially rectangular outer frame forming a side wall. That is, the envelope of the FED includes a windshield, a rear glass, and an outer frame, and each member is hermetically sealed using a sealing agent. The front glass and the rear glass are opposed to each other via a plurality of spacers.

The internal space of the envelope, that is, the space between the opposed windshield and rear glass is typically in a high vacuum state of 10 ⁻³ to 10 ⁻⁶ Pa, and is emitted from the emitter on the rear glass into the space. The emitted electrons collide with the phosphor formed on the inner surface of the windshield to emit light. As a result, the pixels are colored and an image is formed.

  As described above, the inside of the envelope is in a high vacuum state, but the distance between the windshield and the rear glass (typically 1 to 3 mm) even when atmospheric pressure is applied from the outside of the envelope. As described above, a plurality of spacers are interposed between the windshield and the rear glass. However, in the FED having the above structure, the following problems occur due to the presence of the spacer.

  The first problem is image quality such as fluctuations in the electron beam emitted from the emitter caused by charge-up on the spacer surface and poor display color purity in which secondary electrons emitted from the spacer emit other phosphors. It is deterioration.

  The spacer also serves as a support structure that can withstand the pressure applied by the pressure difference between the inside and outside of the envelope of the glass container. However, it is difficult to configure so that a uniform pressure load is applied to a large number of spacers, and a load may be applied to any of the spacers in a concentrated manner.

  The second problem is that, when the concentrated load is applied, there is a concern about the occurrence of cracks on the contact surface between the spacer and the windshield and / or the contact surface between the spacer and the rear glass.

  The third problem is that the operation itself of placing a large number of spacers having a very large aspect ratio between the windshield and the rear glass is technically difficult. The fourth problem is that since a large number of spacers are used, the number of members and the number of assembly steps increase, leading to complication of the manufacturing process and a decrease in productivity. The fifth problem is that, in the process of evacuating the inside of the envelope, the exhaust resistance increases due to the large number of spacers in a narrow space, thereby reducing the productivity.

  As described above, various problems are caused by interposing a spacer between the windshield and the rear glass. However, when the spacer is not used, the windshield and the rear glass are greatly deformed due to a difference in pressure between the inside and outside of the envelope, and in some cases, these glasses are broken. Since the inside of the envelope is at a high vacuum as described above, the end of the short axis among the two orthogonal axes (that is, the long axis and the short axis) parallel to each side on the outer surface of the windshield In the vicinity of the portion, unless the glass is significantly thickened, a tensile stress greatly exceeding the strength of normal glass is generated, leading to breakage.

  Also, do not significantly increase the width of the sealed portion of the windshield and the rear glass, or the sealed portion of the windshield and the outer frame and the sealed portion of the rear glass and the outer frame. As long as the tensile strength greatly exceeds the sealing strength. Therefore, there is a concern about the possibility of destruction of the envelope due to the tensile stress as described above.

  In order to prevent breakage due to tensile stress, it can be eliminated by increasing the thickness of the windshield and rear glass. However, since the emitter is disposed on the surface of the rear glass as described above, it is necessary to increase the thickness until the tensile stress is sufficiently reduced in consideration of the ease of handling in the step of arranging the emitter and various constraints. It is difficult.

  In addition, when the windshield and the rear glass are made thick enough to withstand the pressure difference, the mass of the envelope itself increases and the depth of the FED increases at the same time, so the advantage of the thinness of the FED is somewhat impaired. In this specification, the depth of the FED or the depth of the envelope for the FED refers to the depth in the normal direction with respect to the image display surface.

  Some examples of a vacuum vessel structure that does not use a spacer and is used in a flat panel display device are disclosed in Japanese Patent Application Laid-Open No. 2-239549 (Patent Document 2). FIG. 1 of Patent Document 2 includes a flat face glass (corresponding to a front glass), a curved pressure vessel provided at the rear thereof, and an exterior vessel joined to the outside of the pressure vessel. An example of a vacuum vessel is illustrated.

  Examples of the vacuum vessel of the flat panel display device that does not use other spacers are disclosed in JP-A-5-190121 (Patent Document 3), JP-A 2000-68041 (Patent Document 4), and JP-A 2000-231891. (Patent Document 5), Japanese Patent Application Laid-Open No. 2000-231892 (Patent Document 6), Japanese Patent Application Laid-Open No. 7-220661 (Patent Document 7), and the like.

  As shown in FIG. 6 of the above-mentioned Patent Document 1, an FED emitter (electron-emitting device: patent) such as a SED (Surface-Conduction Electron-Emitter Display: a display using a surface conduction electron-emitting device; a kind of FED). Reference 2074 in Document 1 is on the rear glass (Electron Source Substrate: Reference 2 in Patent Document 1) together with wiring (Reference: Dx, Dy in Patent Document 1) and connection (Reference 2075 in Patent Document 1). It is arranged.

  However, the vacuum envelope (vacuum container) according to FIG. 1 of Patent Document 2 has a structure in which the outer container is positioned on the outside and the pressure-resistant container is positioned on the inner side to form a curved rear panel. . Therefore, when an emitter (cathode) is arranged on the surface of the rear panel as in the invention according to Patent Document 1, the emitter must be arranged on a curved surface, and the depth increases as compared with the case where the emitter is arranged on a flat plate. There is a problem that manufacturing becomes difficult.

  Therefore, the emitter cannot be arranged directly on the rear panel as shown in FIG. 6 of Patent Document 1, and the emitter is separated from the rear panel (pressure vessel and outer container) as shown in FIG. 1 of Patent Document 2. (Cathode) is provided. Therefore, there is a problem that it is difficult to take out the wiring connected to the emitter to the outside of the envelope.

  Further, in FIG. 5 of Patent Document 2, as another aspect of the invention according to FIG. 1, a windshield (reference numeral 1 in Patent Document 2) and a dome-shaped rear panel (metal container 2 in Patent Document 2) are shown. ) Is fused with a thermal fusion agent (reference numeral 4 in Patent Document 2), and the front glass and the rear panel are sandwiched between the channel member members 5. However, even in the case of the vacuum envelope according to FIG. 5 of Patent Document 2, it is difficult to dispose the emitter on the rear panel and to take out the wiring connected to the emitter to the outside of the envelope. was there.

  Further, Patent Document 6 shows a structure having a face panel, a rear envelope, and a substrate in FIG. 2 and sandwiching and supporting the substrate inside the face panel and the rear envelope. As an application example thereof, FIG. 8 of Patent Document 6 discloses a structure for supporting the substrate using a holding pin. However, in the case where the substrate is sandwiched between the face panel and the rear envelope as described above, it is necessary to hermetically seal the face panel and the substrate at the same time as the rear envelope and the substrate. The sealing surface increases. Furthermore, it must be sealed so that the end of the face panel and the end of the rear envelope are substantially opposite. For this reason, the reliability of the above-described sealing portion tends to be impaired. However, Patent Document 6 does not disclose specific means for reducing the stress at the sealed portion. Further, in the case of a structure in which the substrate is supported by the holding pins, there is a problem that it is difficult to handle the conductive wire connected to the emitter.

  Patent Document 7 discloses a flat display composed of a front panel, a rear panel, a side plate, and a pressing plate whose convex side is the atmospheric side in FIG. According to claim 1 of Patent Document 7, it is described that the pressing plate applies a compressive force in the in-plane direction of the panel.

  Further, in Patent Document 7, a convex surface is formed on the atmosphere side surface of the panel, and a compressive force is applied along the panel surface from the end of the panel, so that the center of the panel portion swells toward the atmospheric pressure side. An action is disclosed in which a force is generated and the force generated by reducing the pressure inside is canceled. However, if the convex surface formed on the atmosphere side surface of the panel is insufficient, the effect of canceling the tensile force generated at the panel edge is extremely reduced, or conversely, a dent is created toward the inside where the pressure is reduced, The tensile force is increased and the reverse effect is obtained. That is, in order to make the effect by such an action sufficient, the radius of curvature of the convex surface must be made smaller.

  However, if the radius of curvature is decreased, the image display unit becomes non-flat, and the image display unit is changed from the “planar type” to the “curved surface type”, thereby deteriorating the characteristics of the original flat display and causing a visibility problem. If an attempt is made to eliminate the dent by securing a practical flatness (flatness) while the radius of curvature of the image display portion remains large, the glass must be thickened, in which case the mass increases. It leads to the problem.

  In addition, in the structure of FIG. 2 of Patent Document 7, a moment centering on the contact point between the front panel and the side plate and the contact point between the back panel and the side plate acts. However, in this structure, since the compression force is applied by the pressing plate only in one direction (in-plane direction), the moment is not sufficiently restricted, and the tensile stress at the sealed portion cannot be sufficiently reduced. Furthermore, in paragraph 0009 of Patent Document 7, it is disclosed to reinforce the surface on the atmosphere side of the back panel in order to maintain the overall rigidity. However, the above-mentioned reinforcement is used only for the purpose of increasing the rigidity of the back panel, and does not contribute to the reduction of the tensile stress generated at the sealed portion. As a result, there is a concern about the possibility of destruction in the sealed portion, but Patent Document 7 does not disclose a specific solution.

JP-A-7-230776 JP-A-2-239549 JP-A-5-190121 JP 2001-68041 A JP 2000-231891 A JP 2000-231892 A Japanese Patent Laid-Open No. 7-220661

  In the present invention, in order to solve various problems due to the influence of the spacer described above, the envelope used for the FPD such as the FED has a structure using no spacer (hereinafter referred to as a “spacerless structure”). One purpose. In addition, when setting it as a spacerless structure, it aims also at suppressing the increase in mass by glass becoming thick. A second object is to provide a structure in which the wiring connected to the emitter is excellent.

In order to achieve the first object, the present invention provides:
It consists of a glass container that can be sealed, and a support member that suppresses deformation when a pressure difference occurs inside and outside the glass container,
The glass container consists of a windshield and a rear glass,
The support member includes a rim, a bridge, and a rear plate,
The windshield has a face portion for displaying a substantially rectangular image, and a skirt portion interposed between the face portion and the rear glass, and a seal edge portion at the end of the skirt portion and a cathode are disposed. And the rear glass of the flat plate shape is hermetically sealed,
The rim supports the outer periphery of the outer surface of the skirt part and the face part,
The rear plate is fixed to the rear glass and supports the rear glass,
An envelope for a flat panel display, wherein the rim and the rear plate are joined via a plurality of bridges.

  In addition, the bridge preferably joins the center of the long side of the rim and the rear plate, more preferably joins the center of the short side of the rim and the rear plate, and further adds the bridge. However, it is more preferable that the corner portion of the rim and the rear plate are joined.

  Furthermore, when the inside of the sealed glass container is evacuated, the compression stress value of the outermost surface is 30 MPa or more at a position where the tensile stress generated on the outer surface of the end portion of the face portion of the windshield is maximized. It is even more preferable that a stress layer is formed.

  In order to achieve the second purpose, when the skirt portion of the windshield and the rear glass are hermetically sealed using an adhesive, the outer periphery of the rear glass is larger than the outer periphery of the seal edge portion in the entire circumference. Is preferred. It is preferable that a gap be formed between the rim and the rear plate so that a conductive wire connected to the cathode on the rear plate can be taken out from the gap.

  Moreover, it is preferable that a concave notch is provided on the edge of the rear glass corresponding to the position where the bridge is provided.

  Further, it is preferable that a cushioning material having a Young's modulus of 45 to 80 GPa is interposed between the rim and the windshield. More preferably, the buffer material is made of at least one of aluminum, carbon, magnesium, and low melting point powdered glass.

  Furthermore, it is preferable that an adhesive having a Young's modulus of 3 to 80 GPa is interposed between the rim and the windshield. The adhesive is made of at least one of polyimide, polyetherimide, polyphenylene sulfide, polyethylene terephthalate, polyethylene naphthalate, aromatic polyamide, indium, polyoxymethylene copolymer, silicone resin, and low melting powder glass. Is more preferable. Moreover, you may use together the said buffer material and an adhesive agent.

  Furthermore, it is more preferable that one or more exhaust pipes that communicate with both the rear glass and the rear plate are provided.

  In the windshield, it is more preferable that a recess is provided at a position connected to the skirt portion from the outermost periphery of the face portion to form a step.

  According to the flat display envelope of the present invention, since the support structure for suppressing the deformation of the glass container is provided outside the glass container, the atmospheric pressure can be obtained without providing a spacer between the windshield and the rear glass. Therefore, the tensile stress generated in the sealing portion when a load is applied can be kept low, and safety can be ensured.

  In addition, the envelope for the flat panel display according to the present invention is formed so that the conductive wire connected to the emitter can be easily taken out, so that the workability in the connection process of the electrical system is good and the productivity is improved. Play. That is, a light-weight and safe flat display can be efficiently produced, and is particularly suitable for a display having a cold cathode type electron emission source.

Hereinafter, the present invention will be described in detail.
In the present invention, the flat display means a self-luminous flat display in which the inside is essentially in a high vacuum state and the phosphor is excited and emitted using an electron beam emitted from an emitter. And the envelope 1 for flat panel displays of this invention shown in FIG. 1 is comprised from a glass container and a supporting member. The glass container is composed of a windshield 2 and a rear glass 3, and has a structure in which these two parts can be sealed and sealed. A glass container 4 consisting only of the windshield 2 and the rear glass 3 is schematically shown in FIG. The windshield 2 and rear glass 3 preferably have a Young's modulus (longitudinal elastic modulus) of 70 to 80 GPa.

  Further, the glass container 4 is omitted from the flat display envelope 1 and only the support member is shown in FIG. In addition, the flat display envelope 1 in FIG. 1, the glass container 4 in FIG. 2, and the supporting member in FIG. 3 simply show a quarter of the whole, and actual products are shown in each figure. This is a symmetric shape with the axis A as the center. In addition, these drawings exaggerate the characteristic portions, and the dimensional ratio of each part is different from an actual product. In the present specification, the term “envelope” simply refers to an envelope for a flat panel display.

  The support member includes a rim 5, a bridge 6 and a rear plate 7. The rim 5 supports the outer peripheries of the outer surfaces of the skirt portion 8 and the substantially rectangular face portion 9 of the windshield 2, and the rear plate 7 is fixed to the rear glass 3 to support the rear glass 3. The plate 7 is joined via a plurality of bridges 6. The rim 5 and the bridge 6 may be integrally formed, or two or more members may be joined.

  The rim 5, the bridge 6 and the rear plate 7 are preferably a metal having a Young's modulus of 110 to 250 GPa, more preferably 160 to 210 GPa. Specifically, nickel (Young's modulus = 160 GPa), titanium (Young's modulus = 110 GPa), stainless steel (Young's modulus = 210 GPa), and silicon-containing aluminum (Young's modulus = 220 GPa) are suitable. In practice, as the Young's modulus increases, the specific gravity increases and the thermal expansion coefficient also increases, and the difference in thermal expansion coefficient between the windshield and the rear glass tends to increase, so the above range is preferable.

The glass container 4 that is hermetically sealed can be evacuated to bring the inside 10 into a high vacuum state of 10 ⁻³ to 10 ⁻⁶ Pa. When the inside 10 of the glass container 4 becomes a high vacuum and an atmospheric pressure is applied to the outer surface, a force for deforming the glass container 4 works due to the pressure difference. However, such a deformation can be suppressed by providing the support member including the rim 5, the bridge 6 and the rear plate 7.

  The windshield 2 includes a face portion 9 for displaying a substantially rectangular image, and a skirt portion 8 interposed between the face portion 9 and the rear glass 3. And the glass container 4 is formed by the sealing edge part 11 of the edge part of the skirt part 8, and the flat rear glass 3 in which the cathode is arrange | positioned airtightly.

  When the inside of the glass container 4 that is hermetically sealed is evacuated, a force is applied to the face portion 9 to bend inward. Therefore, it is preferable that the face portion 9 has a curvature and has an outwardly convex shape. When the face portion 9 has a curvature and is convex outward, the face portion 9 becomes relatively flat when the inside of the glass container 4 is evacuated and atmospheric pressure acts on the face portion 9. Therefore, not only the visibility of the image is improved, but also the gap between the face portion 9 and the rear glass 3 can be made more uniform, and the image quality can be improved.

  Like the flat panel display envelope 1 of the present invention, by providing a support member that supports the outer periphery of the outer surface of the skirt portion 8 and the face portion 9 of the windshield 2, the deformation caused by the pressure difference as described above. And the resulting stress can be reduced. Therefore, even if a spacer is not disposed between the windshield 2 and the rear glass 3, it is possible to prevent the glass from being deformed or broken without increasing the width of the seal edge portion 11.

  When the skirt portion 8 of the windshield 2 and the rear glass 3 are hermetically sealed using an adhesive, in order to stabilize the bonding shape of the adhesive and the glass, as shown in FIG. It is preferable that the outer periphery of the rear glass 3 is sufficiently larger than the protruding width of the adhesive on the entire periphery, rather than the outer periphery of the adhesive. Furthermore, it becomes easy to process and take out a large number of conducting wires 12 connected to an emitter (not shown) arranged on the rear glass 3. Furthermore, when the outer periphery of the seal edge portion 11 and the outer periphery of the rear glass 3 have the same dimensions, high-precision positioning is required at the time of sealing both members, and at the same time, if the positioning accuracy is poor, the sealing portion Stress concentration occurs, causing a problem in strength.

  When the above-described pressure difference occurs inside and outside the glass container 4, the highest tensile stress is generated in the vicinity of the long side center (short axis end part) 13 of the substantially rectangular face part 9, and this stress is generated in the glass container. This leads to an increase in the possibility of destruction. Therefore, the bridge 6 that connects the rim 5 and the rear plate 7 of the support member is provided at a position corresponding to the center 13 of the long side of the face portion 9, that is, on the extended line of the short axis of the face portion 9. preferable. The bridge 6 thus provided can effectively prevent the glass from being deformed or broken.

  Further, the tensile stress is also generated in the vicinity of the short side center (long axis end) 14 of the face part and in the vicinity of the corner part (diagonal axis end) 15 of the face part 9. Therefore, the bridge 6 that connects the rim 5 and the rear plate 7 is more preferably provided at a position corresponding to the center 14 of the short side of the face portion 9 and / or a position corresponding to the corner portion 15 of the face portion 9. That is, the bridge 6 is preferably provided on the extension line of the short axis of the face part 9 and / or on the extension line of the diagonal axis of the face part 9. Thereby, the force which tries to deform | transform the glass container 4 can be suppressed, and destruction can be prevented much more effectively.

  Further, the rim 5 also serves as a cover for the sealing material protruding from the sealing portion between the seal edge portion 11 and the rear glass 3, and the jig collides with the sealing material in various manufacturing processes. It also has an effect of preventing the strength from being lowered.

  When the bridge 6 is provided as described above, the position corresponding to the long side center (short axis end part) 13 of the face part 9, the position corresponding to the short side center (long axis end part) 14 of the face part, and the corner part of the face part The bridge 6 does not need to be provided at a position that does not correspond to any of the positions corresponding to 15. Therefore, a gap 16 can be provided between the rim 5 and the rear plate 7. With such a structure, the above-mentioned conducting wire 12 connected to the emitter can be taken out from the gap 16 and the handling of the conducting wire 12 becomes easy. Therefore, it is preferable to provide the gap.

  The rim 5 supports the outer periphery of the outer surface of the skirt portion 8 and the face portion 9 of the windshield 2 as described above, and the Young's modulus is 45 to 80 GPa between the rim 5 and the windshield 2. More preferably, a buffer material is interposed. By interposing a relatively close Young's modulus between the windshield 2 and the rim 5 as the cushioning material, the relative displacement between the windshield 2 and the rim 5 can be reduced even if they are not bonded. The stress generated between the windshield 2 and the windshield 2 in contact with the windshield 2 can be reduced. However, if the cushioning material is thicker than necessary (thickness is 1 mm or more), or if sufficient frictional force does not occur between the cushioning material and the windshield and rim, the relative displacement between the rim and windshield The effect of reducing the thickness is reduced, and the above effect cannot be obtained.

  If the Young's modulus of the cushioning material itself is less than 45 GPa, a sufficient reinforcing effect on the periphery of the windshield 2 cannot be obtained, and if it exceeds 80 GPa, the Young's modulus of the cushioning material becomes larger than the Young's modulus of the windshield, Since the problem that the stress which generate | occur | produces between the windshields 2 becomes remarkably large arises, it is suitable in it being 45-80 GPa. The Young's modulus of the buffer material is more preferably 70 to 80 GPa.

  Specifically, the buffer material is made of at least one of aluminum (Young's modulus: 69 GPa), carbon (Young's modulus: 70 GPa), magnesium (Young's modulus: 45 GPa), and a sealing glass composition (Young's modulus: 70 GPa). It is suitable for obtaining the above-mentioned effect. In addition, the said glass composition for sealing in this invention means what the frit paste containing a low melting glass powder was baked.

  It is also preferable to interpose an adhesive having a Young's modulus of 3 to 80 GPa between the rim 5 and the windshield 2. By interposing the adhesive, the relative displacement between the rim and the windshield can be suppressed by a thin layer of the adhesive, and the reinforcing effect by the rim and the bridge can be enhanced. If the Young's modulus of the adhesive itself is less than 3 GPa, the effect of suppressing relative displacement is small even when the adhesive layer is thin, and if it exceeds 80 GPa, the Young's modulus of the adhesive becomes greater than the Young's modulus of the windshield, Since the problem that the stress which generate | occur | produces between an adhesive agent and the windshield 2 becomes remarkably large arises, it is suitable in it being 3-80 GPa. If the Young's modulus of the adhesive is 40 to 80 GPa, it is more preferable because the relative displacement between the rim 5 and the windshield 2 can be highly suppressed.

  Specific examples of adhesives include polyimide (Young's modulus: 3 GPa), polyetherimide (Young's modulus: 9 GPa), polyphenylene sulfide (Young's modulus: 4 GPa), polyethylene terephthalate, polyethylene naphthalate, aromatic polyamide (aramid) (Young Rate: 80 GPa), indium (Young's modulus: 10 GPa), polyoxymethylene copolymer (Young's modulus: 3 GPa), silicone resin (Young's modulus: 3 GPa), sealing glass composition (Young's modulus: 70 GPa) It is suitable for obtaining the said effect that it consists of one.

  In addition, when the inside of the glass container 4 is evacuated, a compressive stress value of 30 MPa or more is applied to the outermost surface at a position where the tensile stress generated on the outermost surface of the face portion 9 of the windshield 2 is maximized. More preferably, the compressive stress layer is formed by a physical strengthening method or a chemical strengthening method. Since the compressive stress layer is provided, the strength of the unstrengthened glass can be further improved, so that the windshield can be thinned and the weight can be reduced.

  As a method of forming the compressive stress layer, a physical strengthening method as exemplified in Japanese Patent No. 2904667, or a specific alkali ion in glass is replaced with a larger ion at a temperature below the strain point. And any of the chemical strengthening method (ion exchange method) which forms a compressive-stress layer on the surface by the volume increase may be sufficient, and the other method may be sufficient.

  In addition, when actually measuring the stress value of a compressive stress layer, it measures as follows. As one of the stress measurement methods for glass, there is a method of measuring using the property that the difference in refractive index in the principal stress direction generated when the glass is subjected to force is proportional to the stress difference. When linearly polarized light is passed through stressed glass, the transmitted light is decomposed into component waves having polarization planes orthogonal to each other in the direction of the principal stress and having different velocities. Each component wave passes through the glass and one of them is later than the other, and the refractive index of the glass is also different in each principal stress direction depending on the velocity of the component wave. Since the stress difference of glass is proportional to the difference in refractive index, so-called birefringence, the stress can be measured if the phase difference of the component waves is known.

  Stress is measured by measuring a phase difference of a component that transmits light through a glass cross section having a residual stress and vibrates in a main stress direction after transmission by a polarizing microscope using this principle. At this time, a polarizer is disposed before transmitting through the glass, and a plate having a phase difference after transmitting through the glass and an analyzer for detecting polarized light are disposed. Examples of a plate having a phase difference include a Belek compensator, a Babinet compensator, and a quarter wave plate. By using these, it is possible to create a dark line so that the phase difference of the region to be measured is zero, so that the stress value can be known from the amount of adjustment of the compensator.

  In addition, instead of the above various compensators, a sensitive color plate that has an optical path difference of around 565 nm and whose interference color changes due to a slight change in optical path difference is used, so that the position due to slight birefringence after glass transmission. The interference color according to the phase difference can be expressed, and the level of stress can be identified by the color. Using this property, the cross section of the glass is observed and the thickness of the stress layer is measured.

  Further, in the windshield, it is preferable that the thickness t of the center of the face portion is within a predetermined range with respect to the maximum outer diameter d in the diagonal axis direction of the face portion. Specifically, the compression stress layer is not formed by a physical strengthening method or a chemical strengthening method at a position where the tensile stress generated on the outer surface of the end portion of the face portion is maximized, and is molded by a known method. It is preferable that 0.028 ≦ t / d <0.04 when only the compressive stress that is unintentionally generated is observed or when the compressive stress is not observed. On the other hand, when the compressive stress layer is formed by a physical strengthening method, a chemical strengthening method, or the like at a position where the tensile stress generated on the outer surface of the end portion of the face portion is maximum, 0.003 ≦ t / d <0. .028 is preferable.

  Thus, by making the face portion thinner, it is possible to reduce the weight while ensuring the safety of the windshield.

  Further, in the flat display envelope 1 of the present invention, the rear glass 3 and the rear plate 7 are connected to the rear glass 7 and the rear plate 7 in order to improve workability in the exhausting process of evacuating the interior 10 of the glass container 4. One or more tubes (not shown) are preferably provided.

  Further, as shown in FIG. 4, in the windshield 2, it is preferable that a concave portion 17 is provided at a position connecting the outermost periphery of the face portion 9 to the skirt portion 8. In this case, the cross section has a shape in which a step is formed. In general, the glass at the position where the face portion 9 and the skirt portion 8 are connected (hereinafter referred to as “blend R portion”) is thicker than the face portion 9 and the skirt portion 8. Therefore, heat is easily stored in the blend R portion even after heating at the time of molding.

  On the other hand, the center of the face portion, which is relatively thin, quickly dissipates heat and is cooled, so that a temperature difference occurs between the center of the face portion 9 and the blend R portion, and inappropriate deformation or May cause cracks.

  However, if the concave portion is provided in the blend R portion as in the present invention, not only the portion is thin, but also the surface area is increased, so that an efficient heat dissipation / cooling effect is obtained, and the center of the face portion 9 is reduced. The temperature difference can be reduced. Therefore, the above-mentioned problem occurring in the windshield 2 can be solved.

  Furthermore, since the heat capacity of the blend R portion and its peripheral portion is reduced, the entire windshield 2 can be heated more rapidly and uniformly even in the heating process during evacuation for evacuating the container. Therefore, the windshield 2 provided with the concave portion 17 can suppress the generation of unnecessary tensile stress due to the temperature difference at the time of manufacture.

  When the concave portion 17 is provided in the blend R portion of the windshield 2 as described above, a convex portion is provided in the shape of the rim 5 that supports the windshield 2 as shown in FIG. It is preferable that the glass 2 is configured to be in close contact.

  Hereinafter, the envelope for a flat panel display according to the present invention will be described in detail based on examples. In this example, the following values (described in Table 1) were used as conditions.

  Under the above-mentioned conditions, when the atmospheric pressure is applied to the face portion by the finite element method (10-node tetrahedral element) as an example with respect to a quarter model of the envelope as shown in FIG. Numerical analysis of the stress was performed (Examples 1 to 4). In addition, as a comparative example, a numerical analysis of stress was similarly performed on a model including only a glass container and a rear glass reinforcing plate (rear plate) without a rim and a bridge among support members (Examples 5 to 8). . Example 7 is an example in which the width of the seal edge portion is set so that the maximum value of the tensile stress generated in the sealing portion is 4 MPa. In Example 8, the glass thickness at the center of the face portion of the windshield is set so that the maximum value of the tensile stress generated at the end portion of the short axis of the face portion is 11 MPa.

  In Examples 1 to 8, the rear plate, the rim, and the bridge were all made of nickel (Young's modulus: 160 GPa). Hereinafter, Examples 1 to 8 will be described.

  (Example 1) Enclosure having a support member comprising a rim, a bridge, and a rear plate, the width of the seal edge of the windshield being 20 mm, the thickness (t) of the center of the face being 15 mm, the thickness of the rear plate being 15 mm It is the Example of a container.

  (Example 2) This is an example in which the thickness at the center of the face portion is 10 mm thicker than in Example 1 and the other conditions are the same as in Example 1.

  (Example 3) This is an example in which the thickness at the center of the face portion is 15 mm thicker than in Example 1 and the other conditions are the same as in Example 1.

  (Example 4) This is an example in which the thickness at the center of the face portion is 23 mm thicker than in Example 1 and the other conditions are the same as in Example 1.

  (Example 5) An envelope in which the width of the seal edge portion is 10 mm thinner than in Example 1 and includes a rear plate but does not include a rim and a bridge (Comparative Example). Other conditions are the same as in Example 1.

  (Example 6) This is a comparative example in which the width of the seal edge portion is 10 mm thicker than in Example 5 and the other conditions are the same as in Example 5.

  (Example 7) This is a comparative example in which the width of the seal edge part is adjusted to keep the maximum value of the tensile stress generated in the sealing part to 4 MPa or less, and the other conditions are the same as in Example 5.

  (Example 8) In order to suppress the maximum value of the tensile stress generated in the sealing part to 4 MPa or less, the width of the seal edge part is adjusted, the thickness of the center of the face part is made 10 mm thicker than Example 5, and the others are Example 5 It is a comparative example with the same conditions.

  Tables 2 and 3 show the maximum values of the tensile stress generated in the deflection at the center of the face part, the sealing part, and the face part short axis end for Examples 1 to 8 above.

  From the results of the above numerical analysis, the envelopes of Examples 1 to 4 including the support member of the present invention in which the rim, the bridge, and the rear plate are integrated are outside of the examples 5 and 6 that do not include the rim and the bridge. It can be seen that the deflection of the windshield is smaller than that of the envelope. In addition, the envelope of the present invention has a structure that does not have a spacer inside, but it does not excessively increase the width of the seal edge portion, and “is generated at the sealing portion when atmospheric pressure is applied. It was found that the “maximum value of tensile stress” is extremely small.

  Since the examples of Example 1 and Example 2 are based on the premise that a compressive stress layer is formed on the short axis end of the face part, a relatively high maximum tensile stress is generated in the part. Therefore, it is necessary to introduce a reinforced compressive stress so as not to break due to the maximum tensile stress at the face short axis end in the table.

  On the other hand, in the examples of Examples 3 and 4, the maximum tensile stress generated at the short axis end of the face portion is reduced by increasing the thickness of the face portion. Therefore, application of reinforced compressive stress (formation of a compressive stress layer) Is not necessary.

  In the example of Example 1, the deflection at the center of the face part of the windshield is larger than in Examples 2 to 4, but the face part is curved so as to be convex outward before the inside of the envelope is evacuated. By doing so, it is possible to suppress the aforementioned “bending at the center of the face”.

  Specifically, “the face part is flat before the inside of the envelope is evacuated, but after the inside of the envelope is evacuated, the face part bends a (mm) toward the inside of the envelope. In the case of a windshield, the face part after being evacuated is made almost flat by curving the face part shape so that the center of the face part is a (mm) convex outwardly before the vacuum. it can. As a result, an envelope capable of withstanding atmospheric pressure can be provided without excessively thickening the glass even if the face portion is flat, which is preferable.

  Further, when the maximum value of the tensile stress generated in the sealing portion by increasing the width of the seal edge portion without the rim and the bridge is to be suppressed to 4 MPa as in Example 3 and Example 4, Example 7 and Example As in the comparative example of 8, the width of the seal edge portion must be 35 mm. Therefore, it becomes significantly larger than the width (20 mm) of the seal edge portion of the embodiment (Examples 1 to 4) of the present invention.

  When the width of the seal edge portion is increased as in the comparative examples of Example 7 and Example 8, the area to which the sealing material (adhesive) is applied increases, so that the sealing material is appropriately heated during sealing. The difference between the portion to be heated and the portion where heat does not reach sufficiently occurs, resulting in uneven sealing. As a result, the sealing strength is reduced and it is difficult to maintain an appropriate degree of vacuum. In addition, when the maximum outer diameter of the face portion in the diagonal axis direction is set to be constant, the image display area where the phosphor is applied is reduced when the width of the seal edge portion is increased.

  Furthermore, when trying to suppress the maximum tensile stress generated at the short axis end of the face portion low (11 MPa) by increasing the width of the seal edge portion without the rim and bridge and increasing the glass at the center of the face portion, As in Example 8, the width of the seal edge portion is set to 35 mm, and at the same time, the thickness of the glass at the center of the face portion must be set to 25 mm, which leads to a further increase in mass.

  When the rim and the bridge are not provided, which is equal to the effective area of Example 1, the outer diameter of the windshield must be increased in order to suppress the maximum stress of the sealing portion to the same extent.

  For example, the width of the seal edge is 35 mm, the area of the effective screen is the same as in Example 1, no rim and bridge are provided, and the maximum tensile stress generated at the face short axis end is 7 MPa as in Example 4. If the maximum tensile stress generated in the sealing portion is suppressed to 4 MPa, the center of the face portion becomes 35 mm, which is thicker than Example 8 (t = 25 mm). In the case of such a windshield, the mass is 2.53 times the mass of the windshield of Example 1 and 1.02 times the mass of the front panel of Example 4. That is, the absence of rims and bridges leads to a further increase in mass.

  Next, the effect obtained by providing a concave portion in the blend R portion of the windshield will be described. Here, the temperature after the elapse of a predetermined time from the start of cooling is shown for two examples (Example 11) having a concave portion in the blend R portion and an example having no concave portion in the blend R portion (Example 12). Specifically, unsteady heat conduction analysis was performed by the finite element method under the conditions shown in Table 4, and the glass temperature until the temperature of the whole glass was changed from 1000 ° C. to room temperature was obtained by numerical calculation. The numerical calculation is an axisymmetric analysis, and a cross-sectional shape to be analyzed is shown in FIG. 5A shows a cross section of the windshield of Example 11, and FIG. 5B shows a cross section of the windshield of Example 12. FIG. Moreover, the point M in FIG. 5 shows the temperature reference point in a glass peripheral part.

Table 5 shows the temperature change after the start of cooling in Examples 11 and 12. The following T _P (° C.) is the temperature at the temperature reference point M shown in FIG. T _C (° C.) is the temperature at the center of the face portion on the outer surface.

  From the results in Table 5 above, the windshield of the present invention (Example 11) having a recess in the blended R part of the peripheral part is more in the center and periphery of the face part in the cooling process than the windshield having no recess (Example 12). The temperature difference between the parts is very small. Therefore, the generation of unnecessary tensile stress due to the temperature difference can be reduced, and at the same time the cooling time to room temperature can be shortened, which is advantageous from the viewpoint of product quality and molding efficiency.

  The envelope for the flat panel display of the present invention has a strength capable of withstanding the stress generated when atmospheric pressure is applied, so there is no need to provide a spacer between the windshield and the rear glass. Various problems caused by the spacer can be solved. In addition, since the conductive wire connected to the emitter is easy to handle, it is excellent in workability in the manufacturing process and useful.

Explanatory drawing which shows a part (1/4) of the envelope for flat panel displays of this invention. Explanatory drawing which shows a part (1/4) of the glass container in the envelope for flat panel displays of this invention. Explanatory drawing which shows a part (1/4) of the supporting member in the envelope for flat panel displays of this invention. Explanatory drawing which shows the periphery shape of the windshield in the envelope for flat panel displays of this invention. Explanatory drawing which shows the cross-sectional shape and temperature reference point of the windshield which has a recessed part in the blend R part, and the windshield which does not have a recessed part in the blend R part. Explanatory drawing which shows a part (1/4) of the envelope for flat panel displays of this invention which has a windshield which has a recessed part in the blend R part.

Explanation of symbols

1: envelope for flat panel display 2: windshield 3: rear glass 4: glass container 5: rim 6: bridge 7: rear plate
8: Skirt portion 9: Face portion 11: Seal edge portion 12: Conductor 13: Center of long side of face portion 14: Center of short side of face portion 15: Corner portion of face portion 17: Recessed portion

Claims (20)

It consists of a glass container that can be sealed, and a support member that suppresses deformation when a pressure difference occurs inside and outside the glass container,
The glass container consists of a windshield and a rear glass,
The support member includes a rim, a bridge, and a rear plate,
The windshield has a face portion for displaying a substantially rectangular image, and a skirt portion interposed between the face portion and the rear glass, and a seal edge portion at the end of the skirt portion and a cathode are disposed. And the rear glass of the flat plate shape is hermetically sealed,
The rim supports the outer periphery of the outer surface of the skirt part and the face part,
The rear plate is fixed to the rear glass and supports the rear glass,
An envelope for a flat panel display, wherein the rim and the rear plate are joined via a plurality of bridges.   The envelope for a flat panel display according to claim 1, wherein when the skirt portion of the windshield and the rear glass are hermetically sealed, the outer periphery of the rear glass is larger in all circumferences than the outer periphery of the seal edge portion.   The envelope for a flat panel display according to claim 1 or 2, wherein the bridge joins at least the center of the long side of the rim and the rear plate.   The envelope for a flat panel display according to claim 3, wherein the bridge joins the center of the short side of the rim and the rear plate.   The envelope for a flat panel display according to claim 4, wherein the bridge joins a corner portion of the rim and a rear plate.   The gap between the rim and the rear plate is formed so that a conductive wire connected to the cathode on the rear plate can be taken out from the gap. An envelope for a flat display as described in 1.   The envelope for a flat panel display according to claim 3, wherein a concave notch is provided on an edge of the rear glass corresponding to a position where the bridge is provided.   The envelope for flat panel displays according to claim 1, wherein a cushioning material having a Young's modulus of 45 to 80 GPa is interposed between the rim and the windshield.   The envelope for flat panel displays according to claim 1, wherein an adhesive layer having a Young's modulus of 3 to 80 GPa when solidified is interposed between the rim and the windshield.   The flat panel display according to claim 1, wherein a buffer material having a Young's modulus of 45 to 80 GPa and an adhesive layer having a Young's modulus of 3 to 80 GPa when solidified are interposed between the rim and the windshield. Envelope.   The envelope for a flat panel display according to claim 8 or 10, wherein the buffer material is made of at least one of aluminum, magnesium, carbon, and a sealing glass composition.   The adhesive comprises at least one of polyimide, polyetherimide, polyphenylene sulfide, polyethylene terephthalate, polyethylene naphthalate, aromatic polyamide, indium, polyoxymethylene copolymer, silicone resin, and sealing glass composition. The envelope for a flat panel display according to claim 9 or 10.   When the inside of the glass container is evacuated, a compressive stress layer having a compressive stress value of 30 MPa or more on the outermost surface is provided at a position where the tensile stress generated on the outer surface of the end portion of the face portion of the windshield is maximized. The envelope for a flat display according to claim 1, which is formed by a physical strengthening method or a chemical strengthening method.   2. The windshield has a relationship of 0.028 ≦ t / d <0.04, where d is the maximum outer diameter of the face portion in the diagonal axis direction and t is the thickness of the center of the face portion. The envelope for flat panel displays of ~ 12.   14. The windshield has a relationship of 0.003 ≦ t / d <0.028, where d is the maximum outer diameter of the face portion in the diagonal axis direction and t is the thickness of the center of the face portion. An envelope for a flat display as described in 1.   The envelope for flat panel displays according to claim 1, wherein the rear glass and the rear plate are provided with one or more exhaust pipes that communicate with each other. The front glass and the rear glass are sealed with a sealing agent, and the rim has a flange portion protruding outward at a lower end portion on the rear glass side, the width of the flange portion is w ₁ , and the sealing agent is The envelope for a flat panel display according to claim ₁ , wherein w ₁ > w _{2 has} a relationship where w ₂ is a maximum protrusion width of a region protruding beyond the width of the seal edge portion of the windshield.   The envelope for a flat panel display according to any one of claims 1 to 17, wherein a concave portion is provided at a position connecting the outermost periphery of the face portion to the skirt portion in the windshield.   The envelope for a flat panel display according to claim 1, wherein the face portion of the windshield is curved so as to be convex outward. A flat panel display having a cold cathode electron emission source and using the flat panel display envelope according to claim 1.

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