JP2006284832A - Electro-optical device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optical device which can make defects invisible on the substrate surfaces, by filling them with the adhesive applied to the optical sheet. <P>SOLUTION: The electro-optical device is, for example, a liquid crystal display having a pair of substrates. The liquid crystal display also has a polarizer plate and/or a retardation plate, and an adhesive to adhere one of these substrates. This adhesive has an optical refraction index satisfying 1.5+n1(-5≤n1≤5) and is made from the same material as those used generally for optical sheets. In this manner, the defects can be filled and, defects on the substrate are made inconspicuous. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electro-optical device suitable for displaying various information.

  In a liquid crystal display device, a large number of linear or concave scratches are formed on the surface of the substrate of the liquid crystal panel due to the substrate transport process, the substrate bonding process, the cutting process after the substrate bonding, etc., when manufacturing the liquid crystal panel. appear. Such a flaw can be recognized by an observer even after an optical sheet such as a polarizing plate or a retardation plate is pasted, resulting in a linear or circular appearance defect.

  In Patent Document 1, in the cutting process after bonding the substrates, scratches generated on the substrate edge and the cut surface of the substrate are erased by performing wet etching.

  However, in the case of Patent Document 1, there is a problem that a process for performing wet etching on the substrate has to be newly provided in order to erase scratches, which requires man-hours.

JP 2004-258487 A

  This invention is made | formed in view of the above point, and makes it a subject to fill the crack generate | occur | produced on the substrate surface with the adhesive material apply | coated to the optical sheet, and to make it invisible.

  In one aspect of the present invention, an electro-optical device bonds a pair of substrates, an optical sheet having a polarizing plate and / or a retardation plate, the optical sheet, and one of the pair of substrates. The refractive index n of the light of the adhesive material is n = 1.5 + n1 (−5 ≦ n1 ≦ 5).

  The electro-optical device is a liquid crystal display device having a pair of substrates, for example. The liquid crystal display device further includes an optical sheet having a polarizing plate and / or a retardation plate, and an adhesive material for bonding one of the substrates. Here, the refractive index n of light of the adhesive material is 1.5 + n1 (−5 ≦ n1 ≦ 5), and the material of the adhesive material is the same as the adhesive material used for a general optical sheet. Can be used. By doing so, the adhesive material can be filled in the concave portions such as scratches existing on the substrate. Thereby, scratches and the like on the substrate can be made visually inconspicuous.

  As a preferred embodiment of the electro-optical device, the thickness th of the adhesive material is th = 30 + m 2 (−5 ≦ m 2 ≦ 5) [μm].

  In another aspect of the above electro-optical device, the pressure-sensitive adhesive material has a viscosity at which an adhesive surface with the optical sheet becomes flat when bonded to the pair of substrates. Accordingly, it is not necessary to apply temperature and pressure specially to flatten the adhesive surface with respect to the adhesive material, and when adhering to the pair of substrates, the adhesive surface of the adhesive material to the optical sheet is flattened. can do. Therefore, the gap between the optical sheet and the adhesive material can be eliminated.

  In one aspect of the electro-optical device, the one substrate has a fine recess on a surface facing the optical sheet, and the adhesive material enters the recess. Here, the fine recess includes a fine scratch or the like existing on the substrate. Thereby, it is possible to effectively fill the adhesive material into the concave portions such as fine scratches existing on the one substrate.

  In another aspect of the present invention, an electronic apparatus including the electro-optical device as a display unit can be configured.

  In another aspect of the present invention, an optical sheet includes a polarizing plate and / or a retardation plate, and an adhesive material that can be bonded to a substrate, and the refractive index n of light of the adhesive material is n = 1. .5 + n1 (−5 ≦ n1 ≦ 5). By using this optical sheet for a substrate, it is possible to fill a concave portion such as a scratch on the substrate with an adhesive, and to make the scratch on the substrate visually inconspicuous.

  In a preferred embodiment of the optical sheet, the thickness th of the adhesive material is set to th = 30 + m2 (−5 ≦ m2 ≦ 5) [μm].

  In a preferred embodiment of the above optical sheet, the pressure-sensitive adhesive material has a viscosity that makes an adhesive surface with the optical sheet flat when bonded to the pair of substrates.

  In another aspect of the present invention, the method of manufacturing an electro-optical device is such that the refractive index n of light is n = 1.5 + n1 (−5 ≦ n1 ≦ 5) with respect to an optical sheet having a polarizing plate and / or a retardation plate. An adhesive material application step for applying an adhesive material, a bonding step for bonding the optical sheet applied with the adhesive material to a substrate having fine concave portions on the surface, and the adhesive material and the optical sheet. A heating and pressurizing step of heating and pressurizing the adhesive material until the adhesive surface becomes flat, and the adhesive material enters the recess by the heating and pressurizing step.

  In the method for manufacturing the electro-optical device, an adhesive material is applied to the optical sheet, and then the optical sheet and a substrate having fine concave portions on the surface are bonded to each other. This substrate is a substrate constituting the electro-optical device. In the heating and pressurizing step, the pressure-sensitive adhesive material is heated and pressurized until the adhesive surface between the pressure-sensitive adhesive material and the optical sheet becomes flat. Since the adhesive material enters the fine recesses on the surface of the substrate, the adhesive material can be effectively filled against fine scratches existing on the substrate.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the optical sheet of the present invention is applied to a liquid crystal display device.

(Configuration of liquid crystal display device)
A configuration of the liquid crystal display device according to the embodiment of the present invention will be described. FIG. 1 is a cross-sectional view schematically showing a schematic configuration of the liquid crystal display device of the present embodiment. In FIG. 1, an active matrix driving method using a TFD element and a completely transmissive liquid crystal display device is taken as an example.

  In FIG. 1, the liquid crystal display device 100 is roughly divided into a liquid crystal display panel 30 and a backlight 50.

  In the liquid crystal display panel 30, an element substrate 91 and a color filter substrate 92 disposed so as to face the element substrate 91 are bonded to each other through a frame-shaped seal member 3, and liquid crystal is sealed inside the liquid crystal layer 4. Is formed. A conductive member 7 such as a plurality of gold particles is mixed in the frame-shaped seal member 3.

  The upper substrate 2 is formed of glass or the like, and on the inner surface of the upper substrate 2, colored layers 6 </ b> R and 6 </ b> G made of any of R (red), G (green), and B (blue) are provided for each subpixel SG. , 6B are formed. A color filter is constituted by the colored layers 6R, 6G, and 6B.

  A black light-shielding layer BM is formed between the sub-pixels SG in order to prevent light from being mixed from one sub-pixel to the other sub-pixel, with the adjacent sub-pixels SG being separated. The black light shielding layer BM can be made of a black resin material, for example, a black pigment dispersed in a resin.

  A protective layer 18 made of a transparent resin or the like is formed on the colored layer 6 and the black light shielding layer BM. The protective layer 18 has a function of smoothing the level difference of the color filter between the colors, and is corroded or contaminated by chemicals used during the manufacturing process of the color filter substrate 92 and the liquid crystal display device 100 according to the present embodiment. Therefore, it has a function of protecting the colored layer 6. On the surface of the protective layer 18, a transparent electrode (scanning electrode) 14 such as striped ITO (Indium-Tin Oxide) is formed. One end of the transparent electrode 14 extends into the seal member 3 and is electrically connected to the conducting member 7 in the seal member 3.

  On the other hand, the lower substrate 1 is formed of glass or the like, and the scanning lines 13 are formed on the inner surface of the lower substrate 1 with a constant interval. A TFD element 21 and a pixel electrode 11 are formed on the inner surface of the lower substrate 1 for each subpixel. The scanning line 13 is electrically connected to the pixel electrode 11 through the corresponding TFD element. A voltage is applied between the pixel electrode 11 and the transparent electrode 14 to control the orientation of the liquid crystal in the liquid crystal layer 4, thereby changing the light transmittance and performing gradation display.

  An upper optical sheet 9 is disposed on the outer surface of the upper substrate 2, and a lower optical sheet 8 is disposed on the outer surface of the lower substrate 1. The upper optical sheet 9 and the lower optical sheet 8 are optical sheets in which a polarizing plate and a retardation plate are laminated, respectively.

  The backlight 50 has a role of illuminating the liquid crystal display panel 30 for transmissive display. The backlight 50 includes a light guide plate and a light source such as an LED (Light Emitting Diode) on an end surface of the light guide plate. In the backlight 50, light is emitted from the light source, propagates through the light guide plate, and exits toward the liquid crystal display panel 30 along the path T shown in FIG. Thus, the light traveling along the path T passes through the colored layer 6 and the liquid crystal layer 4 and reaches the observer. In this case, light exhibits a predetermined hue and brightness by transmitting through the colored layer 6 and the liquid crystal layer 4. Thus, a desired color display image is visually recognized by the observer.

(Configuration of optical sheet)
Next, the configuration of the optical sheet of the present invention will be described. FIG. 2 is a schematic diagram showing the configuration of the upper optical sheet 9 and the lower optical sheet 8. As described above, the upper optical sheet 9 and the lower optical sheet 8 are sheets in which a polarizing plate and a retardation plate are laminated.

  FIG. 2A shows the configuration of the upper optical sheet 9. As shown in FIG. 2A, in the upper optical sheet 9, the polarizing plate 24a and the phase difference plate 22a are bonded together with an adhesive 23a. The outer surface of the polarizing plate 24a is covered with a protective film 25a. On the other hand, an adhesive material 21 a is applied on the outer surface of the retardation film 22 a for adhesion to the upper substrate 2. That is, the upper optical sheet 9 has a configuration in which the protective film 25a, the polarizing plate 24a, the adhesive material 23a, the phase difference plate 22a, and the adhesive material 21a are arranged in this order from top to bottom.

  FIG. 2B shows the configuration of the lower optical sheet 8. As shown in FIG. 2B, in the lower optical sheet 8, the polarizing plate 24b and the retardation film 22b are bonded together with an adhesive 23b. On the outer surface of the polarizing plate 24b, a diffusion adhesive 26 is applied and adhered to the protective film 25b. On the other hand, an adhesive material 21b is applied on the outer surface of the phase difference plate 22b for adhesion to the lower substrate 1. That is, the lower optical sheet 8 has a configuration in which an adhesive material 21b, a phase difference plate 22b, an adhesive material 23b, a polarizing plate 24b, a diffusion adhesive material 26, and a protective film 25b are arranged in this order from top to bottom. Become.

  In addition, as a structure of the optical sheet of this invention, it is not restricted to the form of the structure of the upper side optical sheet 9 and the lower side optical sheet 8 mentioned above. In short, any optical sheet having an adhesive for adhering to a substrate may be used. For example, an optical sheet having various structures such as one in which an adhesive is applied only to either a polarizing plate or a retardation plate. Can be used as the optical sheet of the present invention.

(Filling the substrate with adhesive material)
Next, the bonding of the substrate and the optical sheet in the liquid crystal display device 100 of the present embodiment will be described using the upper substrate 2 and the upper optical sheet 9 as an example.

  FIG. 3A is an enlarged view showing the upper substrate 2 and the adhesive material 21a before the upper substrate 2 and the upper optical sheet 9 are bonded together. The upper substrate 2 is made of glass such as alkali-free glass. Therefore, a plurality of scratches are generated on the surface of the upper substrate 2 due to a substrate transport process, a substrate bonding process, a cutting process after bonding, and the like during the manufacturing process. FIG. 3A shows a scratch 40 as an example of this scratch. Such a scratch becomes more conspicuous as the depth increases even through a polarizing plate or a retardation plate. Therefore, in a general liquid crystal display device, the upper optical sheet is bonded using an adhesive material after filling a resin-based mold for filling for each scratch to make the scratch inconspicuous. However, such a method takes time and is not preferable from the viewpoint of overall work efficiency.

  FIG. 3B is an enlarged view showing the upper substrate 2 and the adhesive material 21a after the upper substrate 2 and the upper optical sheet 9 are bonded together. In the liquid crystal display device 100 according to the present embodiment, the adhesive 21a of the upper optical sheet 9 is used to bond the upper optical sheet 9 and the upper substrate 2 as shown in FIG. It is assumed that the flaws that are present are filled at the same time.

  When the viscosity of the adhesive 21a is high, it has a strong adhesive force between the upper substrate 2 and the upper optical sheet 9, but it is difficult to fill the scratch 40 of the upper substrate 2 and when the viscosity is low. Although it is excellent for filling the scratch 40 of the upper substrate 2, the adhesive force between the upper substrate 2 and the upper optical sheet 9 is weakened. Accordingly, the viscosity value of the adhesive material 21a is within the range of the viscosity value that can fill the scratches of the upper substrate 2, that is, the range of the viscosity value of the resin-based mold for filling, and the upper optical sheet 9 It is set to a value included in both ranges of the viscosity value range in which the upper substrate 2 can be bonded. An adhesive material used in a general optical sheet satisfies the above conditions. Therefore, as the adhesive 21a of the optical sheet of the present invention, the same material as the adhesive used in a general optical sheet, for example, an acrylic resin material can be used.

  The adhesive material 21 a needs to have a light refractive index comparable to the light refractive index of the upper substrate 2. If the refractive index of the light of the adhesive material 21a does not have the same refractive index as that of the light of the upper substrate 2, the light is refracted at the boundary between the adhesive material 21a and the upper substrate 2 in the scratch 40. As a result, the scratch 40 on the upper substrate 2 becomes visually noticeable. Specifically, since inorganic alkali glass (refractive index = 1.5 to 1.9) is used as the material of the upper substrate 2, the refractive index of light is 1.5 + n1 (− Those within the range of 5 ≦ n1 ≦ 5) are desirable.

  As mentioned above, the optical sheet of this invention can be filled with the crack on a board | substrate by using the adhesive material which has the conditions mentioned above, Furthermore, the crack on the board | substrate can be made inconspicuous.

  However, when the adhesive material 21a has the same thickness and the same viscosity as the adhesive material in a general optical sheet, as shown in FIG. There is a possibility that the adhesive surface 45 of the pressure-sensitive adhesive material 21a with the phase difference plate 22a is recessed, and a gap 41 is generated between the phase difference plate 22a and the pressure-sensitive adhesive material 21a. Therefore, even if the adhesive material 21a fills the scratch 40 of the upper substrate 2, the adhesive surface 45 with the phase difference plate 22a needs to be kept flat.

  Therefore, in the optical sheet according to the present invention, the adhesive material 21a is provided with a sufficient thickness so that the adhesive surface 45 with the phase difference plate 22a is kept flat even when the scratch 40 of the upper substrate 2 is filled. In addition, the generation of the gap 41 between the retardation plate 22a and the adhesive material 21a is suppressed. As a specific manufacturing method, first, the adhesive material 21a is applied thickly on the outer surface of the upper optical sheet 9 as an adhesive material application step in the present invention. Thereafter, the upper optical sheet 9 coated with the adhesive material 21a is bonded to the upper substrate 2 as a bonding step in the present invention. Subsequently, as the heating and pressurizing step in the present invention, the pressure-sensitive adhesive material 21a is heated and pressure is continuously applied until the adhesive surface 45 with the phase difference plate 22a becomes flat.

  First, the thickness of the adhesive material 21a in the adhesive material application process will be specifically described. In FIG. 3A, the depth of the scratch 40 is shown as “dep”, and the thickness of the adhesive material 21a is shown as “th”. The depth dep of the scratch 40 generated in the upper substrate 2 is generally 3 to 5 [μm]. The thickness of the adhesive material of a general optical sheet is 25 + m1 (−5 ≦ m1 ≦ 5) [μm]. The thickness th of the pressure-sensitive adhesive material 21a in the upper optical sheet 9 of the present invention is required to be a thickness that does not cause the adhesive surface 45 to be recessed even when the scratch 40 is filled. Accordingly, considering that the depth dep of the scratch 40 is 3 to 5 [μm], the thickness th of the adhesive material 21a is set to be 10 [μm] thicker than the thickness of the adhesive material in a general optical sheet. It is considered desirable. Therefore, it is preferable that the thickness of the adhesive material 21a is set to 35 + m2 (−5 ≦ m2 ≦ 5) [μm].

  Next, after bonding the upper optical sheet 9 coated with the adhesive material 21a to the upper substrate 2 as a pasting process, as the heating and pressurizing process, the adhesive surface 45 to the retardation plate 22a is applied to the adhesive material 21a. Heat and pressurize until is flat. Specifically, the adhesive material 21a is heated at a temperature higher than the temperature and pressure applied to the adhesive material only for attaching the optical sheet to the substrate in a general liquid crystal display device, and is pressed for a long time. Need to be done.

  FIG. 4 is an enlarged view of the upper substrate 2 and the adhesive material 21a when the adhesive material 21a is heated at a high temperature and pressed for a long time. After the upper optical sheet 9 coated with the adhesive material 21a heated at a high temperature is bonded to the upper substrate 2, pressure is applied in the direction of the arrow Pr for a long time. The adhesive material 21a is easily deformed by increasing the viscosity when heated at a high temperature. Therefore, the pressure-sensitive adhesive material 21a is deformed in the direction of the broken line arrow Tr1 by applying pressure in the direction of the arrow Pr for a long time, and the adhesive surface 45 with the phase difference plate 22a is flattened, and the gap in the upper optical sheet 9 41 can be eliminated. In addition, the pressure-sensitive adhesive material 21a is deformed in the direction of the broken line arrow Tr2 when pressure is applied for a long time. Therefore, flaws existing on the upper substrate 2 can be more effectively filled. Specifically, when the pressure-sensitive adhesive material 21a is heated at 60 ° C. and then pressurized for 30 minutes, the gap 41 can be eliminated.

  In the above-described example, the adhesive material 21a of the upper optical sheet 9 fills the recesses such as scratches of the upper substrate 2, but the lower optical sheet also applies to the recesses such as scratches of the lower substrate 1. It is needless to say that the adhesive material 21b of 8 can be filled by performing the same operation as that of the adhesive material 21a of the upper optical sheet 9 described above.

(Modification)
In the above-described embodiment, the adhesive material is given a thickness, and by applying a certain temperature and pressure, the gap generated in the optical sheet is eliminated. In the modification of the present invention, unlike the above-described embodiment, the adhesive material of the optical sheet is previously given a viscosity lower than that of the adhesive material 21a in the above-described embodiment, whereby high-temperature heating or Eliminates the need to apply pressure to the adhesive for a long time. In other words, the adhesive material is preliminarily given a viscosity at which the adhesive surface with the phase difference plate is flattened simply by applying temperature and pressure only for attaching the optical sheet to the substrate.

  Also by this, when the optical sheet is bonded to the substrate, the adhesive material can be deformed and the adhesive surface of the adhesive material with the phase difference plate can be flattened, which occurs between the optical sheet and the adhesive material. The gap can be eliminated. In this case, compared with the above-described embodiment, it is not necessary to apply a high temperature and a long-time pressure for flattening the bonding surface, so that the time required for bonding the optical sheet and the substrate is shortened. can do.

[Electronics]
Next, specific examples of electronic devices to which the liquid crystal display device 100 according to the present invention can be applied will be described with reference to FIG.

  First, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) will be described. FIG. 5A is a perspective view showing the configuration of this personal computer. As shown in the figure, a personal computer 710 includes a main body 712 having a keyboard 711 and a display 713 to which the liquid crystal display device 100 according to the present invention is applied.

  Next, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a mobile phone will be described. FIG. 5B is a perspective view showing the configuration of the mobile phone. As shown in the figure, the cellular phone 720 includes a plurality of operation buttons 721, a reception port 722, a transmission port 723, and a display unit 724 to which the liquid crystal display device 100 according to the present invention is applied.

  Note that, as an electronic device to which the liquid crystal display device 100 according to the present invention can be applied, in addition to the personal computer shown in FIG. 5A and the mobile phone shown in FIG. Type / monitor direct-view type video tape recorder, car navigation device, pager, electronic notebook, calculator, word processor, workstation, videophone, POS terminal, digital still camera, etc.

It is sectional drawing which shows typically schematic structure of the liquid crystal display device of this embodiment. It is a schematic diagram which shows the structure of an upper side optical sheet and a lower side optical sheet. It is an enlarged view which shows an upper board | substrate and an adhesive material. It is an enlarged view which shows an upper board | substrate and an adhesive material. It is the schematic which shows the electronic device to which the illuminating device of this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Lower substrate, 2 Upper substrate, 9 Upper optical sheet, 8 Lower optical sheet, 21a, 21b Adhesive material

Claims (9)

A pair of substrates;
An optical sheet having a polarizing plate and / or a retardation plate;
An adhesive material that bonds the optical sheet and one of the pair of substrates; and
The refractive index n of light of the adhesive material is
n = 1.5 + n1 (−5 ≦ n1 ≦ 5)
An electro-optical device characterized by that. The thickness th of the adhesive material is
th = 30 + m2 (−5 ≦ m2 ≦ 5) [μm]
The electro-optical device according to claim 1, wherein:   2. The electro-optical device according to claim 1, wherein the adhesive material has a viscosity at which an adhesive surface with the optical sheet becomes flat when the adhesive material is bonded to the pair of substrates. The one substrate has a fine recess on a surface facing the optical sheet,
The electro-optical device according to claim 1, wherein the adhesive material enters the concave portion.   An electronic apparatus comprising the electro-optical device according to claim 1 in a display unit. A polarizing plate and / or a retardation plate,
An adhesive material that can be bonded to the substrate,
The refractive index n of light of the adhesive material is
n = 1.5 + n1 (−5 ≦ n1 ≦ 5)
An optical sheet characterized by that. The thickness th of the adhesive material is
th = 30 + m2 (−5 ≦ m2 ≦ 5) [μm]
The optical sheet according to claim 6, wherein:   The optical sheet according to claim 6, wherein the pressure-sensitive adhesive material has a viscosity at which an adhesive surface with the polarizing plate and / or the retardation plate is flat when bonded to the pair of substrates. For an optical sheet having a polarizing plate and / or a retardation plate, an adhesive material applying step of applying an adhesive material having a light refractive index n of n = 1.5 + n1 (−5 ≦ n1 ≦ 5),
A bonding step of bonding the optical sheet coated with the adhesive material to a substrate having a fine recess on the surface;
A heating and pressurizing step for heating and pressurizing the pressure-sensitive adhesive material until an adhesive surface between the pressure-sensitive adhesive material and the optical sheet becomes flat, and
The method of manufacturing an electro-optical device, wherein the pressure-sensitive adhesive material enters the concave portion by the heating and pressurizing step.

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