JP2005010738A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent display defect such as yellow discoloration caused nearby terminal part sides of an effective display part by eliminating unevenness of stress due to a setting shrinkage of resin in a display device constituted by laminating a panel for display and an additional function panel with resin. <P>SOLUTION: In the liquid crystal panel 10 for display, the layer thickness of resin 30 is made uniform by extending a 1st polarizing plate 15 arranged on the side of a surface laminated on a patterned optical retardation plate 20 to the reverse side of a display driver terminal 11, i.e. the formation area of the resin 30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a panel structure of a display device. For example, the panel is provided in order to provide added value such as displaying a three-dimensional image (hereinafter referred to as a 3D image) on a display medium such as a liquid crystal, an organic EL, and an inorganic EL. The present invention relates to a display device in which another panel or the like is bonded to a unit.

  A normal liquid crystal display that displays a 2D image (planar image) has a display panel unit in which deflection plates are attached to the upper and lower surfaces of a display liquid crystal panel. As long as simple 2D image display is performed, there is no need to attach other panels to the display panel unit.

  However, in recent years, there has been a display device in which another panel member (hereinafter referred to as an additional function panel) is bonded to the display panel unit in order to add a function such as, for example, a 3D image (stereoscopic image) display. Has been developed.

As a display device capable of displaying a 3D image, for example, Patent Document 1 and Patent Document 2 disclose a configuration in which a parallax barrier is bonded as an additional function panel. For example, Patent Document 3 and Patent Document 4 disclose a configuration in which a microlens array is bonded as an additional function panel.
JP 10-229567 A (publication date August 25, 1998) JP-A-10-123461 (publication date May 15, 1998) JP 2002-72134 A (publication date March 12, 2002) JP 10-20246 A (publication date January 23, 1998)

  However, in a display device in which an additional function panel is further bonded to a display panel unit in which a deflection plate is bonded to a display liquid crystal panel, the following problems occur in the conventional configuration.

  That is, as shown in FIG. 3, the display device 100 has a configuration in which the additional function panel 120 is bonded to the display panel unit 110 with the resin 150. The display panel unit 110 includes a liquid crystal layer 113 sandwiched between a CF (Color Filter) substrate 112 and a TFT (Thin Film Transistor) substrate 114, and the TFT substrate 114 has a surface opposite to the liquid crystal layer 113. A polarizing plate 115 is attached.

  Since the polarizing plate 115 only needs to function in the active area (effective display area) of the display panel unit 110, the polarizing plate 115 is attached with an area that covers only the active area. Note that the active area is approximately equal to the area of the CF substrate 112. In the display panel unit 110, a polarizing plate 116 is also bonded to the surface of the CF substrate 112 opposite to the liquid crystal layer 113.

  In the display device in which the additional function panel 120 is bonded to the display panel unit 110, the display panel unit 110 and the additional function panel 120 are bonded together with the resin 150. In addition, as the additional function panel 120, for example, a plate-like phase difference panel made of glass or the like is used when a function capable of experiencing a 3D image is added to the display device.

  When the display panel unit 110 and the additional function panel 120 are bonded to each other with the resin 150, the cell gap of the panel in the display panel unit 110 changes due to the stress generated when the resin 150 is cured. A yellow discoloration zone occurs.

  In particular, the terminal side (the side where the driver terminal area is disposed on the TFT substrate) on which the chip for controlling the display device is mounted is likely to be stressed by the shrinkage of the adhesive resin (庇 structure: FIG. 3) The portion surrounded by a broken line), the degree of yellow discoloration band is also strong, causing a problem in display quality (see FIG. 4).

  For example, in a display device using a patterned retardation plate (parallax barrier) for the additional function panel 120, in order to perform 3D display, alignment between the picture element in the display panel unit 110 and the pattern of the additional function panel 120 is performed. It needs to be done properly. For this reason, it is necessary to provide alignment marks on both the display panel unit 110 and the additional function panel 120. However, since the TFT panel for mobile phones has a narrow frame structure, for example, on the TFT substrate 114 side of the display panel unit 110, The alignment mark must be set at a terminal portion avoiding wiring or the like. For this reason, it is necessary to provide an alignment mark on a region facing the terminal portion on the TFT substrate 114 side also on the additional function panel 120 side, and such a display device necessarily has the above-described eaves structure.

  In addition, even in a panel in which a yellow discoloration band does not occur immediately after assembly of the module, the same symptoms often occur during long-term storage. Therefore, in the display device in which the additional function panel is further bonded to the display panel unit, it is necessary to eliminate the fundamental cause of the yellow discoloration band.

  The present invention has been made to solve the above-described problems, and its purpose is to provide a display device in which an additional function panel is bonded to a display panel unit with a resin, such as a yellow discoloration band in the display panel unit. An object of the present invention is to provide a display device capable of preventing the occurrence of display defects.

  In order to solve the above problems, the display device of the present invention includes a display panel (for example, a liquid crystal display panel) and an additional function panel (for example, a parallax barrier or a microlens lens array for adding a 3D display function). In the display device bonded with the resin layer, the resin layer is formed as a layer having a uniform thickness in the entire formation region.

  In a display device having a structure in which a display panel and an additional function panel are bonded together by a resin layer, if there is a non-uniform portion in the thickness of the resin layer, non-uniform stress is applied when the resin is cured and contracted. This non-uniform stress causes a change in cell thickness in the display panel, resulting in a display defect due to the change in cell thickness (for example, the occurrence of a yellow discoloration band in a liquid crystal display panel).

  On the other hand, according to the above configuration, by making the layer thickness of the resin layer that bonds the display panel and the additional function panel uniform, non-uniform stress acts on the display panel during resin curing shrinkage. Can be eliminated, and display defects due to cell thickness fluctuations can be prevented.

  The additional function panel is provided to give an additional display function such as a stereoscopic display function to the display device. However, the type of the added display function and the additional function panel itself is particularly limited. It is not something.

  In order to solve the above problems, another display device of the present invention is opposed to a display panel provided with a functional film on at least one surface, and a surface of the display panel provided with the functional film. In the display device in which the display panel and the additional function panel are bonded together by the resin layer, the functional film is outside the effective display area of the display panel. It is characterized by being formed so as to include a resin layer forming region.

  In a display device having a functional film on the side of the display panel that is bonded to the additional function panel, conventionally, the functional film covers only a functionally necessary area, that is, an effective display area. Was formed. However, in the configuration in which the functional film is formed in the effective display area, the resin film in the resin layer forming area outside the effective display area does not exist, so the thickness of the resin layer in that area becomes thick, and the resin cure shrinkage Inhomogeneous stress is generated, resulting in display defects due to cell thickness fluctuations.

  On the other hand, according to the above configuration, the functional film is formed so as to include the resin layer formation region even outside the effective display region of the display panel, so that the resin layer has a uniform thickness. And display defects due to fluctuations in cell thickness can be prevented.

  Moreover, in the said display apparatus, the said display panel can be set as the structure which is a liquid crystal display panel, and the said functional film is a polarizing plate.

  In a display device using a liquid crystal display panel as a display panel, a polarizing plate is required as a functional film because of its display method. Further, when the polarizing plate is formed so as to cover only the effective display area, display trouble such as yellowish discoloration is likely to occur, and the application of the present invention is suitable.

  Further, in the display device, the additional function panel may be configured to give the display device a stereoscopic display function.

  Examples of the additional function panel that gives the display device a stereoscopic display function include a parallax barrier and a microlens array. In such an additional function panel, the display panel is positioned and pasted with high accuracy. Since alignment is necessary, it is necessary to form alignment marks outside the effective display area. For this reason, the resin layer is also formed outside the effective display area, and the application of the present invention is suitable.

  As described above, the display device of the present invention has a configuration in which the resin layer is formed as a layer having a uniform thickness in the entire formation region.

  Therefore, by making the layer thickness of the resin layer that bonds the display panel and the additional function panel uniform, it is possible to eliminate non-uniform stress acting on the display panel when the resin cures and shrinks, and the cell thickness varies. It is possible to prevent display defects caused by the problem.

  One embodiment of the present invention will be described with reference to FIGS. 1 and 2 as follows. In the following description, a patterned retardation plate is used as an additional function panel, and a display device with a 3D display function added is illustrated.

  As shown in FIG. 1, the display device according to the present embodiment has a configuration in which a patterned retardation plate 20 is bonded to a display liquid crystal panel 10 using a resin 30. For example, a UV curable resin is suitably used as the resin 30.

  The display liquid crystal panel 10 is provided as a TFT liquid crystal display panel, and includes a first polarizing plate (functional film) 15, an active matrix substrate (for example, a TFT substrate) 14, a liquid crystal layer 13, and a counter substrate (for example, a CF substrate). 12, the second polarizing plate 16 is laminated. The active matrix substrate 14 is provided with a display driver terminal 11 in a region outside the active area, and image data corresponding to an image to be displayed is FPC (Flexible Printed Circuits) connected to the display driver terminal 11. ) And the like (not shown).

  If the display liquid crystal panel 10 has a function of generating a display screen, the display method (TN method, STN method, etc.) or drive method (active matrix drive or passive matrix drive) in the display liquid crystal panel 10 is used. Etc.) is not particularly limited.

  As shown in FIG. 2A, the patterned retardation plate 20 has a configuration in which an alignment film 22 is formed on a transparent substrate 21 and a liquid crystal layer 23 is further stacked thereon. Further, a third polarizing plate 24 is disposed on the opposite side of the liquid crystal layer 23 with respect to the transparent substrate 21. Further, in the active area of the patterned retardation plate 20, as shown in FIG. 2B, the first region 20A (indicated by the hatched portion in the drawing) and the second region having different polarization states, respectively. Regions 20B (indicated by projected portions in the figure) are alternately formed in a stripe shape.

  Although not shown, the patterned retardation plate 20 is formed with an alignment mark for use in alignment at the time of bonding to the display liquid crystal panel 10. Although the alignment mark is also provided on the display liquid crystal panel 10, the alignment mark on the display liquid crystal panel 10 side must be set at a terminal portion avoiding wiring or the like. For this reason, the patterned retardation plate 20 side has substantially the same area as the display liquid crystal panel 10 in order to make the alignment mark face the alignment mark of the display liquid crystal panel 10.

  Next, the display operation of this display device will be described.

  First, in the display device shown in FIG. 1, incident light emitted from the light source is first incident on the patterned retardation plate 20. The light incident on the patterned retardation plate 20 is converted into polarized light by passing through the third polarizing plate 24, and then passes through the transparent substrate 21, the alignment film 22, and the liquid crystal layer 23.

  The first region 20A and the second region 20B of the patterned retardation plate 20 have passed through the liquid crystal layer 23 in the first region 20A because the rubbing direction with respect to the alignment film 22, that is, the direction of the slow axis is different. The polarization state differs between the light and the light that has passed through the liquid crystal layer 23 in the second region 20B. The patterned retardation plate 20 is set to act as a half-wave plate depending on the birefringence anisotropy and the film thickness of the liquid crystal layer 23.

  The light that has passed through the patterned retardation plate 20 is incident on the first polarizing plate 15 of the display liquid crystal panel 10. Here, the polarization axis of the light passing through the first region 20A of the patterned retardation plate 20 is parallel to the transmission axis of the polarizing plate 15, and the light passing through the first region 20A is the first polarizing plate 15. Shall be transmitted. On the other hand, the polarization axis of the light that has passed through the second region 20B forms an angle of 90 ° with the transmission axis of the first polarizing plate 15, and the light that has passed through the second region 20B is blocked by the first polarizing plate 15. Shall be.

  That is, the function of the parallax barrier (parallax barrier means) is achieved by the optical action related to the patterned retardation plate 20 and the first polarizing plate 15, and the first region 20A in the patterned retardation plate 20 is a transmission region. The second region 20B becomes a blocking region.

  The light that has passed through the first polarizing plate 15 undergoes different optical modulation between the pixel that performs black display and the pixel that performs white display in the liquid crystal layer 13 of the display liquid crystal panel 10, and is optically modulated by the pixel that performs white display. Only the received light is transmitted through the second polarizing plate 16 to display an image.

  At this time, light that has been given a specific viewing angle by passing through the transmission region of the parallax barrier passes through pixels corresponding to the right-eye image and the left-eye image in the display liquid crystal panel 10, thereby causing the right eye to pass. The image for use and the image for the left eye are separated into different viewing angles, and 3D display is performed.

  In the display device having the above configuration, the display liquid crystal panel 10 and the patterned retardation plate 20 are bonded to the resin 30 as described above. At this time, the first polarizing plate 15 is not only the active area region. The active matrix substrate 14 is formed so as to overlap with the area of the display driver terminal 11. In other words, the first polarizing plate 15 is formed so as to include the adhesive layer forming region if there is a region where the adhesive layer is formed of the resin 30 even in the region outside the active area.

  The first polarizing plate 15 may be formed so as to cover at least the area of the active area only for the purpose of achieving the 3D display function in the display device. On the other hand, in the display device according to the present embodiment, the first polarizing plate 15 is formed so as to cover the region of the display driver terminal 11 in the active matrix substrate 14, so that the ridge structure portion is formed by resin curing shrinkage. It is characterized in that the stress generated in the terminal is eliminated and the yellowish discoloration of the terminal side is prevented.

  This will be specifically described as follows. That is, in the display device having the conventional configuration as shown in FIG. 3, since the first polarizing plate 115 covers only the active area, the layer of the resin 150 is located between the portion where the first polarizing plate 115 is located. The layer thickness is different from the non-existing part. Thus, when the layer thickness of the resin 150 is different, the stress generated at the time of curing the resin becomes large at the portion where the layer thickness is large (the portion where the first polarizing plate 115 is not present, that is, the terminal portion region), and the stress is not uniform. Occurs. This non-uniform stress leads to cell thickness fluctuation, that is, yellowish discoloration of the terminal side.

  On the other hand, in the display device according to the present embodiment, the first polarizing plate 15 is formed so as to cover the region of the display driver terminal 11 in the active matrix substrate 14. For this reason, the layer thickness of the resin 30 is uniform up to the entire formation surface of the resin layer outside the active area, and in the active area, it is possible to avoid non-uniform normal direction stress caused by the structure during resin curing. it can. Thereby, the stress which generate | occur | produces in the eaves structure part by resin hardening shrinkage | contraction does not act on the effective display part of a panel. Therefore, variation in cell thickness can be suppressed, and yellowish discoloration of the terminal portion side can be prevented.

  The present invention provides a display panel for a mobile phone, for example, in a display panel having a narrow frame (three sides free) structure in which a terminal portion on which a chip for controlling a display device is mounted is only one side of the display panel. Yellowing discoloration that occurs can be prevented.

  Furthermore, yellow discoloration can also be prevented for a display panel having terminal portions on the upper and lower sides of the display panel and a display panel having terminal portions on the left and right sides, such as a large panel. In addition, when the terminal part exists in two or more sides, the polarizing plate may be extended on all sides where the terminal part exists, or the polarizing plate is extended only on the side where yellowish discoloration is to be suppressed. You may let them.

  That is, the polarizing plate is preferably formed in a region including the entire region where the resin layer is formed, but the polarizing plate is extended only at a side where it is desired to suppress yellowish discoloration, and the resin layer is formed in a specific region. The thickness may be made uniform.

  In the display device in which the display panel and the additional function panel are bonded together by the resin layer, the method of making the thickness of the resin layer uniform includes conditions such as the amount of the bonded resin, the pressure and balance at the time of bonding, and the like. In addition, there is a method of using a resin obtained by adding an appropriate amount of a gap retaining material such as a plastic bead to the bonding resin.

  Further, when the display panel is a liquid crystal panel, pressure sealing treatment is performed in the manufacturing process to reduce the influence of the stress generated by the bonded resin curing shrinkage except for excess liquid crystal in the liquid crystal panel. You can also

  In addition, the present invention prevents display defects such as yellowish discoloration caused by applying a resin curing stress to the display panel when an additional function panel made of an optical element or the like is bonded to the display panel with a resin. However, the display panel to be applied is not limited to the liquid crystal panel. For example, in other display panels such as organic EL and inorganic EL, when a functional film is provided outside the display panel and the additional functional panel is attached to the functional film arrangement surface side, a display device is manufactured. In addition, if a display defect due to cell thickness variation occurs, the display defect can be prevented. Moreover, although the functional film illustrated in this Embodiment is a polarizing plate, a functional film is not specifically limited, For example other than a polarizing plate, an antireflection film etc. may be sufficient.

  In this embodiment, 3D display is exemplified as a function added to the display device, and a configuration using a patterned retardation plate is exemplified as an additional function panel. However, the additional function panel is not limited to the patterned retardation plate. For example, the present invention is also effective when a known microlens array for performing 3D display is used as an additional function panel. Further, the additional function added to the display device of the present invention is not limited to 3D display, and any additional function can be obtained by directly bonding the additional function panel to the display panel using an adhesive. The present invention is applicable regardless of the type of the additional function panel.

  For example, the liquid crystal display panel according to the present invention can perform screen display in which different video sources are displayed in each of the first display area and the second display area separated by the parallax barrier means.

  As an example of the usage of such a liquid crystal display panel, it is used for a display device that displays an image of a car navigation system for a driver in a driver's seat of a car and a television broadcast for a passenger in a passenger seat. Can be considered. When different images are displayed for multiple observers, the parallax barrier is shielded so that the light transmitted through each pixel can be separated as an image to be observed by each of the multiple observers at a predetermined distance. What is necessary is just to set the arrangement pattern of a part and a permeation | transmission part suitably.

  In addition, a switching liquid crystal panel is attached to the display liquid crystal panel as an additional function panel, a 2D / 3D switching function, a display state in which different images are displayed for a plurality of viewpoints, and a normal display state (the same in all screen areas) The present invention is also applicable to a display device that realizes a switching function with a screen display for displaying a video source.

It is sectional drawing which shows schematic structure of the display apparatus which concerns on this invention. It is a figure which shows the structural example of the patterned phase board | substrate in the said display apparatus, Fig.2 (a) is sectional drawing, FIG.2 (b) is a front view. It is a top view which shows the generation | occurrence | production location of the yellowish discoloration zone in the conventional display apparatus. It is sectional drawing which shows schematic structure of the conventional display apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display liquid crystal panel 12 Counter substrate 13 Liquid crystal layer 14 Active matrix substrate 15 1st polarizing plate (functional film)
20 Patterned retardation plate (additional function panel)
30 resin (resin layer)

Claims (5)

In a display device in which a display panel and an additional function panel are bonded together by a resin layer,
The display device, wherein the resin layer is formed as a layer having a uniform thickness in the entire formation region. A display panel having a functional film on at least one surface, and an additional functional panel bonded to the surface of the display panel having the functional film, which is bonded to the display panel. In the display device in which the functional panel is bonded to the resin layer,
The display device according to claim 1, wherein the functional film is formed so as to include a resin layer forming region outside the effective display region of the display panel.   The display device according to claim 2, wherein the display panel is a liquid crystal display panel, and the functional film is a polarizing plate.   4. The display device according to claim 1, wherein the additional function panel is a display device having a stereoscopic display function.   4. The display device according to claim 1, wherein the additional function panel gives the display device a function of displaying different images for a plurality of viewpoints.

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