JP2014106382A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device capable of significantly reducing a reflected light quantity due to an external light and also reducing a reflection of an image from the other display panel so as to obtain a high contrast.SOLUTION: An image display device 1 is constituted of: a frame 3 having a concave shape whose cross-section is a curve; a plurality of organic EL panels 2 arranged on the surface of a concave surface of the frame 3; and a circularly polarizing plate 10 mounted on a display surface 2f of respective organic EL panels 2. An axis 4 vertical to the cross-section is made symmetrical, and the plurality of organic panels 2 is divided into two areas. A transmission axis 23a of a polarizing plate 23 of the organic EL panel 2 on the one area 1a is arranged to be parallel to the axis 4, and the transmission axis 23b of the polarizing plate 23 of the organic EL panel 2 on the other area 1b is arranged to be orthogonal to the axis 4. Consequently, the reflection of the image from the other organic EL panel can be reduced.

Description

  The present invention relates to a large-sized image display device configured by arranging a large number of organic electroluminescent display panels (organic EL panels), and in particular, a large number of organic EL panels are arranged so as to form a concave surface having a curved section. The present invention relates to an image display device using a concave tiling display.

  2. Description of the Related Art In recent years, a large-scale display has become a mainstream method in which a large number of LEDs (light emitting diodes) are arranged. In such a large LED display, the LED array density increases as the resolution is increased, which increases the cost. On the other hand, in order to realize a large display at a low price, there is a method in which a plurality of flat displays (for example, LCD panels, PDPs, EL display panels, etc.) as image display elements (or display units) are arranged in a matrix. It is valid.

  As a conventional image display element constituting such a large display, for example, a bottom emission type organic EL panel can be used. The bottom emission type organic EL panel includes a front substrate on which an organic EL layer is formed and a back substrate bonded to the front substrate. The front substrate and the back substrate are opposed to each other with a predetermined interval, and a plurality of image elements and a plurality of electrode terminals for controlling them are arranged in the gap, and a light emitting layer is formed, The periphery is sealed with a sealing material, and light emitted from the organic EL layer is taken out from the back surface of the front substrate, that is, the display surface, which is a non-facing surface between the front substrate and the back substrate.

  The opposite surface of the back substrate to the front substrate is subjected to counterbore processing for disposing a hygroscopic material, and the periphery of the panel not subjected to counterbore processing is bonded to the front substrate by a sealing material. The sealing material is formed to prevent moisture deterioration of the organic EL layer that is weak against moisture, and at the same time, the strength of the panel is maintained.

  However, in the bottom emission type organic EL panel, the contrast of the image may be lowered due to the influence of the reflected light from the external light. As a countermeasure, the organic EL display device disclosed in Patent Document 1 prevents the contrast from being lowered. Therefore, a circularly polarizing plate is attached to the display surface of the bottom emission type organic EL panel.

JP 2009-92998 A

  However, in an image display device of a concave tiling display that is enlarged by attaching a circularly polarizing plate to the display surface of the organic EL panel and arranging a large number of organic EL panels so that concave surfaces having a curved section are formed. The angle of the mirror image of the transmission axis of the polarizing plate constituting the circularly polarizing plate provided in each of the left and right organic EL panels with the axis perpendicular to the cross section (for example, the most concave position of the concave surface) symmetrical is not substantially orthogonal For this reason, the left and right images are reflected on the opposite organic EL panel with the axis being symmetrical, and there is a problem in that the display quality is lowered.

  The present invention has been made to solve the above-described problems, and in an image display device in which a large number of organic EL panels are arranged so as to form concave surfaces, the amount of light reflected by external light is significantly reduced. In addition, an object of the present invention is to provide an image display device that can reduce the reflection of an image from another organic EL panel and obtain high contrast.

  In order to solve the above-described problems, an image display device according to the present invention includes a plurality of display panels arranged so as to have at least one concave surface having a predetermined cross-section, and a position where the display panel is installed on the display surface of the display panel. A plurality of display panels that are divided into two regions, each having a circularly polarizing plate constituted by a phase difference plate and a polarizing plate disposed on the phase difference plate, with an axis perpendicular to the cross section being symmetrical. The transmission axis of the polarizing plate of the display panel in one of the divided regions is parallel to the axis, and the transmission axis of the polarizing plate of the display panel in the other region is orthogonal to the axis. It is characterized by being arranged.

  According to the image display device of the present invention, the transmission axes of the polarizing plates of the left and right organic EL panels are orthogonal to each other with respect to the axis perpendicular to the concave curved cross section, so that not only external light but also other organic EL The reflection of an image from the panel can be reduced, and the contrast can be improved.

1 is a schematic configuration perspective view showing an image display device in Embodiment 1. FIG. FIG. 2 is a cross-sectional view of a bottom emission type organic EL panel applied to the image display device in the first embodiment. FIG. 3 is a schematic configuration perspective view of the bottom emission type organic EL panel of FIG. 2. It is sectional drawing of the organic electroluminescent panel for demonstrating the reflection preventing function by a circularly-polarizing plate. 3 is a diagram showing a transmission axis of a polarizing plate of the image display device in Embodiment 1. FIG. It is a figure which shows the transmission axis of the polarizing plate of the image display apparatus in a prior art example. FIG. 5 is a diagram showing a display state of an image in the first embodiment. It is a figure which shows the display state of the image in the prior art example of FIG. 6 is a diagram illustrating a relationship with transmission axes of left and right polarizing plates in an image reflection state according to Embodiment 1. FIG. It is a figure which shows the relationship with the transmission axis of the polarizing plate on either side in the image reflection state in a prior art example. FIG. 5 is a schematic configuration perspective view showing another embodiment of the image display device in the first embodiment.

  Hereinafter, an image display apparatus according to an embodiment of the present invention will be described with reference to FIGS.

Embodiment 1 FIG.
FIG. 1 is a schematic perspective view of the image display device according to Embodiment 1, and FIG. 2 is a cross-sectional view of a bottom emission type organic EL panel of the image display device. FIG. 3 is a schematic perspective view of the bottom emission type organic EL panel of FIG. FIG. 4 is a schematic cross-sectional view of an organic EL panel for explaining the antireflection function of the circularly polarizing plate. FIG. 5 is a diagram illustrating the transmission axis of the polarizing plate of the image display device. FIG. 7 is a diagram showing a display state of the image in FIG. FIG. 6 is a diagram showing the transmission axis of the polarizing plate of the image display device in the conventional example, and FIG. 8 is a diagram showing the display state of the image in FIG. FIG. 9 is a diagram showing the relationship between the transmission axes of the left and right polarizing plates in the image reflection state of FIG. FIG. 10 is a diagram showing a relationship with the transmission axes of the left and right polarizing plates in the image reflection state of FIG.

  As shown in FIG. 1, an image display device 1 has a plurality of bottom emission type organic EL panels 2 as a display panel, and a concave shape having a curved line 3c having a circular section, and a plurality of organic surfaces are formed on the surface of the concave surface. And an EL panel 2 arranged and attached to a frame 3. As shown in FIG. 2, each organic EL panel 2 includes a transparent front substrate 6, an organic EL light emitting layer 5 formed of a light emitting layer or an electrode formed on the back surface of the front substrate 6, and a front substrate 6. A back substrate 7 bonded to the back surface by a sealing material 8, a hygroscopic material 9 formed on the inner surface side of the back substrate 7, and a circularly polarizing plate 10 provided on the display surface of the front substrate 6. Yes. As shown in FIG. 4, the circularly polarizing plate 10 includes a λ / 4 retardation plate 22 and a polarizing plate 23, and the λ / 4 retardation plate 22 is polarized on the front substrate 6 side. It arrange | positions so that the board 23 may come.

  In the organic EL panel 2, a control signal including a scanning signal and a data signal is applied to a plurality of electrode terminals from a drive control circuit. As an example of a wiring connection method for applying a control signal to these electrode terminals. In addition, as shown in the example of FIG. 3, an end surface wiring connection method in which a step portion is provided around the image element portion, that is, a joint portion between adjacent image element portions, and wiring is connected to the electrode terminal exposed to the step portion. There is a central wiring connection system in which the back substrate 7 is divided to provide a V-shaped groove 12 at the center, and the wiring 14 is connected to the electrode terminal 13 through a pit provided at the bottom of the groove 12. Here, a control signal is applied to the organic EL light emitting layer 5 from the drive control circuit via the connector 15 via the wiring 14 and the electrode terminal 13. In an image display device of a tiling display configured by arranging a plurality of bottom emission type organic EL panels 2, for example, in order to maintain the continuity of display so as not to make the joint between the organic EL panels 2 conspicuous, non-display is performed. A center wiring connection method in which the non-display portion can be narrowed is more suitable than an end face wiring connection method in which the portion becomes wider. As a method of pulling out the wiring 14 from the electrode terminal 13 by the central wiring connection method, for example, a V-shaped groove 12 is formed on the back substrate 7 side which is a terminal connection portion of the organic EL panel 2, and an anisotropic conductive film is formed. There are a method of using the wiring 14 to pull out, a method of using a conductive paste using Ag, Cu, carbon or the like, a method of wire bonding, and the like.

  Further, a counterbore process is generally performed between the back substrate 7 and the front substrate 6 to dispose the hygroscopic material 9, and the periphery of the back substrate 7 not subjected to the counterbore process is sealed. 8 is bonded to the front substrate 6. In order to protect the organic EL light-emitting layer 5 which is weak against moisture from moisture deterioration, a material with low moisture permeability is used for the sealing material 8, and at the same time, the panel strength is maintained. In order to prevent moisture deterioration of the organic EL light emitting layer 5, a hygroscopic material 9 is disposed in the counterbore processed portion. In addition, when the moisture-proof performance of the sealing material 8 is sufficient, the moisture-absorbing material 9 may not be disposed.

FIG. 4 is a schematic cross-sectional view of an organic EL panel for explaining the antireflection function by the circularly polarizing plate. For example, in the circularly polarizing plate 10 composed of the λ / 4 phase difference plate 22 and the polarizing plate 23, the incident light 20 from the outside is a straight line that is a component parallel to the transmission axis (polarization axis) 23 a by the polarizing plate 23. Only polarized light 20p is transmitted. Here, linearly polarized light, which is a component parallel to the absorption axis 23t, is absorbed. The transmitted linearly polarized light 20p is converted into circularly polarized light 20c by the λ / 4 phase difference plate 22. The circularly polarized light 20c reflected by the organic EL light emitting layer 5 and the wiring of the organic EL panel 2 passes through the λ / 4 phase difference plate 22 again, so that the polarization direction is rotated 90 degrees from the linearly polarized light 20p at the time of incidence. The linearly polarized light 20t is obtained. However, since this linearly polarized light 20 t is parallel to the absorption axis 23 t of the polarizing plate 23, the reflected light 21 cannot be transmitted through the polarizing plate 23 and is absorbed. Thereby, it is possible to obtain a high-contrast image in which the influence of external light such as sunlight or illumination is reduced. The circularly polarizing plate 10 may be a polarizing plate, a λ / 2 phase difference plate, and a λ / 4 phase difference plate. A circularly polarizing plate in which a polarizing plate and a λ / 4 retardation plate having a broadband wavelength dispersion function are laminated can also be used. With such a configuration, the antireflection performance can be improved as compared with a circularly polarizing plate in which a polarizing plate and a λ / 4 retardation plate are laminated.

  The above describes the general structure of a bottom emission type organic EL panel having a circularly polarizing plate. However, in the image display device of the concave tiling display according to the present embodiment, a top emission type organic EL panel is also used. It can also be used. In the top emission type organic EL panel, light emitted from the opposite direction of the bottom emission type organic EL panel, that is, from the back surface of the back substrate which is the non-facing surface of the front substrate and the back substrate is taken out. In the present embodiment, the bottom emission type organic EL is described as an example. For convenience, the substrate on the side from which the emission light is obtained in the bottom emission type organic EL panel is referred to as a front substrate. Therefore, in the top emission type organic EL panel, the back surface of the back substrate is the display surface. Note that a circularly polarizing plate is attached to the display surface of the top emission type organic EL panel with an adhesive or an adhesive for the same purpose as in the case of the bottom emission type organic EL panel. That is, since the antireflection function by the circularly polarizing plate having the characteristics of the present invention is the same as that of the bottom emission type organic EL panel, the description of the structure and the manufacturing method of the top emission type organic EL panel is omitted.

  Next, operations and effects of the image display apparatus according to the first embodiment will be described with reference to FIGS. FIG. 5 shows transmission axes (polarization axes) 23a and 23b of the polarizing plate 23 of the image display device 1 having a concave shape according to the present embodiment. The axis 4 is perpendicular to the cross section of the frame 3 having the concave surface. In the organic EL panel 2a arranged in the right region 1a of the axis 4 when viewed from the front, the transmission axis 23a of the polarizing plate 23 is In the organic EL panel 2 b which is orthogonal to the left side region 1 b of the axis 4, the transmission axis 23 b of the polarizing plate 23 is parallel to the axis 4. Here, for example, the shaft 4 passes through the most concave portion of the concave surface of the frame 3 and is orthogonal to the arcuate curve 3c. On the other hand, in the general conventional image display device 31 having the concave shape shown in FIG. 6, in the organic EL panel 32a arranged in the right region 31a of the axis 4, the transmission axis 33a of the polarizing plate 33 is The angle is 45 ° (or 135 °) with respect to the axis 4, and in the organic EL panel 32b disposed in the left region 31b of the axis 4, the transmission axis 33b of the polarizing plate 33 is also the axis 4 The angle is the same as 45 ° (or 135 °).

  In the above description, the transmission axis 23a of the polarizing plate 23 of the organic EL panel 2a in the right region 1a is orthogonal to the axis 4, and the transmission axis 23b of the polarizing plate 23 of the organic EL panel 2b in the left region 1b is Although it was set as the case where it became parallel with respect to the axis | shaft 4, the case where the transmission axes 23a and 23b of the polarizing plate 23 of the left and right organic electroluminescent panels 2a and 2b are reverse may be sufficient.

  Next, the image reflection phenomenon will be described by comparing the image display device 1 of the present embodiment with the conventional image display device 31. In the image display device 1 of the present embodiment shown in FIG. 5 and the conventional image display device 31 shown in FIG. 6, the display character 'B' is displayed as an image on the organic EL panels 2a and 32a in the right regions 1a and 31a, respectively. A display example when 24 and 34 are displayed is shown in FIGS. In the conventional image display device 31 of FIG. 8, image reflections 35 and 36 are seen on the organic EL panel 32a in the left region 31b, but in the image display device 1 of the present embodiment of FIG. No reflection of the image was observed on the organic EL panel 2a in the area 1b.

  As shown in FIG. 10, in the conventional image display device 31, the transmission axis 33 a of the polarizing plate 33 of the organic EL panel 32 a in the right region 31 a is at an angle of 45 ° with respect to the axis 4. , The outgoing polarized light 140 of the display character 'B' 34 coming out from the organic EL light emitting layer 5 shown in FIG. 8 also has the same angle of 45 °. However, although the transmission axis 33b of the polarizing plate 33 of the organic EL panel 32b in the left region 31b is also at an angle of 45 ° with respect to the axis 4, the polarized light 140a incident on the organic EL panel 32b of the display character 'B'34. , 140b and the absorption axis of the polarizing plate 33 of the organic EL panel 32b (perpendicular to the transmission axis 33b) are not necessarily orthogonal depending on the viewing position and have a predetermined angle. (Θ1, θ2 ≠ 90 °), the light absorptance of the display character 'B' 34 is lowered. As a result, the light that is not absorbed by the polarizing plate 33 is transmitted through the circularly polarizing plate 10 and the organic EL panel 2b. And is reflected by the organic EL light-emitting layer 5 and the electrode, and the linearly polarized light at the time of incidence is again rotated and returned by the circularly polarizing plate 10. However, since it does not coincide with the absorption axis of the polarizing plate 33, the reflected light is not sufficiently absorbed by the polarizing plate 33, and is taken out to the outside and an image reflection phenomenon occurs. However, the position where the image is reflected differs depending on the viewing angle, and since θ1 and θ2 are different, there is also a difference in the amount of absorption, and the display characters 'B' 35 and 43 to be reflected are reflected in the image depending on the position. The brightness is different.

  On the other hand, as shown in FIG. 9, in the image display device 1 of the present embodiment, the transmission axis 23 a of the polarizing plate 23 of the organic EL panel 2 a in the right region 1 a is orthogonal to the axis 4. For this reason, the output polarized light 130 of the display character 'B' 24 emitted from the organic EL light emitting layer 5 shown in FIG. 7 is also orthogonal to the axis 4. However, since the transmission axis 23b of the polarizing plate 23 of the organic EL panel 2b in the left region 1b is parallel to the axis 4, the incident polarized light 130a, 130b to the organic EL panel 2b of the display character 'B' 24 and the organic Since the absorption axis (perpendicular to the transmission axis 23b) of the polarizing plate 23 of the EL panel 2b is parallel regardless of the viewing position, the light absorptance from the display character 'B' 24 is maximized, and the organic EL panel 2a The amount of light entering the interior was greatly reduced and the amount of reflected light was reduced, so no reflection was observed.

  In the above description, the image is displayed in the right area of the image display device. However, the same applies to the case where the image is displayed in the left area or when the image is displayed in both areas. I can say.

  As described above, in the image display device according to Embodiment 1, the transmission axes of the polarizing plates of the circularly polarizing plates of the organic EL panel arranged in the left and right regions are symmetrical with respect to the axis orthogonal to the cross-sectional curve. In addition to the reflected light from the external light, the reflection from the display image of another organic EL panel can be reduced, and the contrast can be improved.

  In the above embodiment, the case where the display panel is an organic EL panel has been described. However, the present invention can also be applied to a reflective LCD (liquid crystal) panel, an inorganic EL panel, and other display panels. The effect of can be demonstrated.

  In the above embodiment, the cross section of the image display device is a concave shape having an arc curve. However, the shape of the concave surface is not particularly limited, and has a curve such as a parabolic curve other than the arc. It may be.

  The display surface of each organic EL panel used in the above embodiment may be flat or curved according to the concave shape.

  In the above embodiment, the case where the organic EL panel is attached to the surface of the frame having the concave shape has been described. However, the organic EL panel may be arranged so that the concave surface is formed by a plurality of organic EL panels without using the frame. Good.

  In the above embodiment, the case where the transmission axes of the polarizing plates of the left and right organic EL panels are made different from each other with the most concave position of the concave surface of the image display device as an axis has been described. The same effect can be expected for other positions on the concave surface.

  In the above embodiment, an example of an image display device having one concave surface has been described. However, as shown in FIG. 11, an image display device in which a plurality of concave surfaces are connected in a wave shape may be used. The effect can be expected.

  Moreover, in the said embodiment, although the circular polarizing plate was shown about the example arrange | positioned on the display surface of each organic electroluminescent panel, each one large circularly polarized light which covers the whole organic electroluminescent panel of a right-and-left area | region is shown. The case where the board is arrange | positioned may be sufficient.

  Note that the present invention is not limited to the above-described embodiment, and the embodiment can be appropriately modified and omitted within the scope of the invention.

  Moreover, in the figure, the same code | symbol shows the same or an equivalent part.

1,100 image display device, 1a, 32a right region, 1b, 32b left region, 2, 2a, 2b, 32a, 32b organic EL panel, 2f display surface, 3 frame, 3c arc curve, 4 axes, 5 organic EL Light emitting layer, 6 front substrate, 7 back substrate, 10 circularly polarizing plate, 22 λ / 4 phase difference plate, 23, 33 polarizing plate, 23a, 23b, 33a, 33b transmission axis (polarization axis), 23t absorption axis, 24, 34 Display character 'B', 31 Conventional image display device, 35, 36 Reflected display character 'B', 130, 140 Emission polarization, 130a, 130b, 140a, 140b Incident polarization.

Claims (5)

A plurality of display panels arranged to have at least one concave surface with a predetermined cross-section being curved;
A circularly polarizing plate comprising a retardation plate installed on the display surface of the display panel and a polarizing plate disposed on the retardation plate,
The plurality of display panels are divided into two regions with an axis perpendicular to the cross section being symmetric, and the transmission axis of the polarizing plate of the display panel in one of the divided regions is parallel to the axis An image display device, wherein the transmission axis of the polarizing plate of the display panel in the other region is arranged so as to be orthogonal to the axis.   The image display apparatus according to claim 1, wherein the curve is an arc.   The image according to claim 1, wherein the retardation plate is a λ / 4 retardation plate or a combination of a λ / 4 retardation plate and a λ / 2 retardation plate. Display device.   The image display apparatus according to claim 1, wherein the display panel is an organic EL panel. The image display apparatus according to claim 4, wherein the organic EL panel is a bottom emission type or a top emission type.

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