JP2007017833A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device that can be improved in picture quality when a transparent cover is laid in front of a light emitting element. <P>SOLUTION: The display device 1 comprises a plurality of light emitting elements 11 arranged in longitudinal and lateral directions, and transparent covers 17 placed in front of the plurality of light emitting elements 11. The transparent cover 17 has a surface profile comprising downward faces 31 directing downward and upward faces 33 directing upward which alternately appear. The transparent cover 17 in front of the light emitting elements 11 can reduce external light reflected to a viewing direction. The downward faces 33 are inclined with respect to a horizontal plane and composed of curved planes, which can reduce uneven reflection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device in which light emitting elements are arranged.

  Conventionally, a large display device in which a large number of light emitting elements are arranged in a matrix is known (for example, Patent Document 1). The light emitting element is typically an LED element. This type of display device is installed, for example, in an exercise facility, a building wall surface, an event venue, or the like.

  FIG. 7 shows a local configuration of a conventional display device. In the display device 101, the LED element 103 is provided on the LED substrate 105. The LED element 103 is a bullet type. A terminal behind the LED element 103 is attached to the LED substrate 105. A plate-shaped light shielding louver 107 protrudes above the LED element 103. The light shielding louver 107 prevents the LED element 103 from being exposed to external light such as sunlight. The periphery of the LED element 103 is filled with black silicon 109. The silicon 109 ensures waterproofness.

  In the display device 101, the configuration of FIG. 7 continues in the vertical direction and the horizontal direction, thereby forming a large display panel (see Patent Document 1).

As shown in the example of FIG. 7, a conventional general display device is configured with a bullet-type LED element. On the other hand, in recent years, display devices including surface-mounted (SMD) LED elements have been proposed. Such a display device is advantageous in terms of reduction in thickness. However, since the surface side of the light emitting part does not have a waterproof structure like a bullet-type LED, the place of use has been restricted indoors.
JP 2000-181363 A (page 3-4, FIG. 1)

  However, in order to take advantage of thinning and the like, it is desired to provide a surface-mounted LED even in an outdoor display device. In order to meet such a requirement, it is conceivable to dispose a waterproof transparent cover in front of the LED. However, since external light such as sunlight is reflected in the viewing direction by the transparent cover, there is a problem that the black level is raised and the contrast is lowered. Although it is conceivable to lengthen the light shielding louver, the length of the light shielding louver is also limited in order to ensure a vertical viewing angle.

  As described above, in the conventional display device, when a waterproof transparent cover is provided in front of the light emitting element, there is a problem that the image quality is deteriorated due to reflection of external light.

  The present invention has been made to solve the conventional problems, and an object of the present invention is to provide a display device capable of improving image quality when a transparent cover is provided in front of a light emitting element.

  The display device of the present invention includes a plurality of light emitting elements arranged in a vertical direction and a horizontal direction, and a transparent cover positioned on a front side of the plurality of light emitting elements, and the transparent cover is a downward surface facing downward. And an upward surface facing upwards have a surface shape that appears alternately in the vertical direction. The upward surface may be a horizontal surface or a surface facing obliquely upward.

  With this configuration, the transparent cover has a surface shape in which a downward surface and an upward surface appear alternately, so the external light reflected in the viewing direction by the transparent cover can be reduced, and high contrast with black sinking even in a bright environment Can be displayed, and the image quality can be improved.

  In the display device of the present invention, the downward surface is inclined downward with respect to a horizontal plane, and is formed of a curved surface. With this configuration, it is possible to reduce the unevenness of reflection of external light from below, make the brightness uniform, and further improve the image quality. With a simple configuration in which the surface shape of the transparent cover is devised, it is possible to provide a good image quality in which the influence of not only external light from above but also external light from below is reduced.

  In the display device of the present invention, the downward surface is a concave curved surface. With this configuration, it is possible to reduce uneven reflection on the transparent cover while reducing external light reflection as much as possible.

  In the display device of the present invention, an antireflection layer is provided on the surface of the transparent cover. With this configuration, it is possible to further reduce reflection of external light and improve image quality.

  In one embodiment of the present invention, the display device includes a plurality of light emitting elements arranged in a vertical direction and a horizontal direction, and a transparent cover positioned on a front side of the plurality of light emitting elements. Each of the plurality of surfaces reflects incident light in a direction different from the viewing direction. The direction or angle of each divided surface may be sequentially changed and set so that each surface reflects incident light in a direction different from the viewing direction. The directions of the adjacent divided surfaces may be set differently. Also with this configuration, it is possible to reduce external light reflected in the viewing direction by the transparent cover, display high contrast with black sinking even in a bright environment, and improve image quality.

  The present invention provides a display device having an effect that external light reflected in a viewing direction by a transparent cover can be reduced and image quality can be improved by providing the transparent cover with a surface shape in which an upward surface and a downward surface appear alternately. be able to.

  Hereinafter, a display device according to an embodiment of the present invention will be described with reference to the drawings.

  A display device according to an embodiment of the present invention is shown in FIGS. FIG. 1 shows the configuration of the main part, and FIG. 2 shows the overall configuration. In FIG. 2, the display device 1 has a plurality of display panels 3. The plurality of display panels 3 are attached to the attachment frame 5 and united to form a large display device 1. Each display panel 3 has a plurality of light emitting elements arranged in a matrix in the vertical and horizontal directions. In the entire display device, a plurality of light emitting elements are arranged in the vertical direction and the horizontal direction. The light emitting element is an LED element. The display device 1 is installed, for example, on an exercise facility or a building wall surface.

  FIG. 1 is a vertical sectional view of the display panel 3. FIG. 1 shows a part of the display panel 3. More specifically, FIG. 1 shows the upper two LED elements 11 in one display panel 3. The LED element 11 is a surface mount type (SMD) LED element, and is mounted on the LED substrate 13. A plate-shaped light shielding louver 15 protrudes forward slightly above each LED element 11. The light shielding louver 15 blocks outside light from above such as sunlight.

  A transparent cover 17 is disposed on the front side of the LED element 11. The transparent cover 17 is held by cover holding walls 19 and 21 provided on the light shielding louver 15. As illustrated, the cover holding walls 19 and 21 protrude upward and downward from the respective light shielding louvers 15. In other words, the upper light shielding louver 15 of each LED element 11 has a cover holding wall 21 projecting downward, and the lower light shielding louver 15 of each LED element 11 projects upward. have. These cover holding walls 19 and 21 hold the transparent cover 17 from above and below. The LED element 11 is covered with the transparent cover 17, the upper and lower cover holding walls 19 and 21, and the upper and lower light shielding louvers 15, thereby ensuring the waterproofness of the LED element 11 and the LED substrate 13.

  FIG. 3 is a view of a part of the display device 1 as viewed from the front. The plurality of LED elements 11 are arranged in the lateral direction with a constant interval. The light shielding louver 15 has an elongated shape extending in the lateral direction. A plurality of parallel light shielding louvers 15 are arranged in the vertical direction. Each light shielding louver 15 is positioned on each horizontal row of the LED elements 11.

  The transparent cover 17 also has an elongated shape extending in the lateral direction. The transparent cover 17 is a band-shaped or bar-shaped member. A plurality of parallel transparent covers 17 are arranged in the vertical direction. And the transparent cover 17 is located so that each row | line | column of the horizontal direction of the LED element 11 may be covered.

  FIG. 4 shows the transparent cover 17 alone. The plurality of parallel transparent covers 17 are connected to each other at the connection portion 23 to form an aggregate. The transparent cover 17 is made of a transparent resin.

  In the description so far, each band member in FIG. 4 is called the transparent cover 17. However, the plurality of belt-like members in FIG. 4 may be collectively referred to as a transparent cover.

  Moreover, the one strip | belt-shaped member has covered the some LED element 11 located in a line with the horizontal direction. That is, one strip member functions as a cover for the plurality of LED elements 11. Therefore, the front area of each LED element 11 may be called a transparent cover. In this case, one belt-like member is a member in which a plurality of transparent covers are combined.

  The cover assembly in FIG. 4 is molded in advance with a cover manufacturing mold. Then, the cover aggregate of FIG. 4 is set in a mold that forms the light shielding louver 15. Then, a black resin is poured into the mold. Thereby, the front panel provided with the light shielding louver 15 and the transparent cover 17 (and the cover holding walls 19 and 21) of FIG. 1 is formed. The front panel is positioned in front of the LED element 11 and the LED element 13 and performs a light shielding function and a waterproof function.

  Alternatively, the black portion (the light shielding louver 15 and the cover holding walls 19 and 21) may be formed in advance with a mold. And a black member may be set to another metal mold | die, and transparent resin may be inject | poured.

  Next, the surface shape of the transparent cover 17 will be described. Referring to FIG. 1, the transparent cover 17 has a surface shape in which a downward surface 31 facing downward and an upward surface 33 facing upward appear alternately in the vertical direction. In the present embodiment, the downward surface 31 is an inclined surface and has a downward angle with respect to the horizontal direction. Further, the upward surface 33 is a horizontal plane. The upward surface 33 connects the lower end of the downward surface 31 positioned on the upper side to the upper end of the downward surface 31 positioned on the lower side. Thereby, as shown in the drawing, the surface shape is jagged and saw-shaped.

  In other words, it can be said that the transparent cover 17 has a shape in which a plurality of crests (saw teeth) are arranged in the vertical direction. Each peak has a downward surface 31 and an upward surface 33. The shape of each peak is a triangle, so that the surface shape is serrated.

  In FIG. 1, three peaks are shown on each transparent cover 17 for easy understanding of the drawing. However, in practice, it is preferable that more mountains are provided, and a fine jagged shape is preferably formed. For example, the interval between the upper and lower light shielding louvers 15 is 8 mm. The LED element 11 has a diameter of 2 mm. Furthermore, the vertical dimension (width) of the transparent cover 17 is 4 mm. In this case, eight ridges (jags) are suitably provided on the transparent cover 17.

  Moreover, in this Embodiment, the downward surface 31 is comprised by the concave curved surface. As will be described later, this configuration contributes to the reduction of reflection unevenness.

  Further, although not shown, an anti-reflection layer (Anti Reflection Coat) is provided on the surface of the transparent cover 17.

  The configuration of the display device 1 according to the present embodiment has been described above. In the display device 1, the above-described configuration is continuously repeated in the horizontal direction and the vertical direction, whereby the entire display device 1 is configured.

  Next, the operation of the display device 1 will be described. Here, reflection of external light on the transparent cover 17 will be described.

  Referring to FIG. 5, sunlight is assumed as outside light L in the present embodiment. Sunlight is incident obliquely from above. The viewing direction V is assumed to be obliquely downward.

  The outside light L passes under the light shielding louver 15 and is irradiated on the surface of the transparent cover 17. A part of the outside light L is reflected by the upward surface 33 to become upward reflected light L1. Further, a part of the external light L is reflected by the downward surface 31 and becomes reflected light L2 that is directed downward from the viewing direction V. In this way, the external light L is reflected in a direction that does not affect the viewer. Therefore, the external light reflected toward the viewer is reduced, and a high-contrast image in which the black level is sunk is obtained.

  This point will be further described. In the conventional display device, the light blocking louver blocks the LED itself from outside light. Also in this embodiment, a light shielding louver 15 is provided. However, in the present embodiment, a waterproof transparent cover 17 is disposed in front of the LED element 11. The height of the light shielding louver 15 is not sufficient to block outside light to the transparent cover 17. Therefore, external light hits the transparent cover 17. In order to secure the light shielding function, it is conceivable to increase the light shielding louver 15. However, the height of the light shielding louver 15 is limited from the viewpoint of securing the viewing angle. Therefore, it is difficult to prevent the light shielding louver 15 from irradiating the transparent cover 17 with external light.

  Thus, it is not easy for the light shielding louver 15 to sufficiently perform the light shielding function of the transparent cover 17 disposed further in front of the LED element 11. Under such circumstances, in the present embodiment, the transparent cover 17 has a saw-like surface shape as described above. Thereby, the influence of reflection of external light on the transparent cover 17 can be reduced, and the image quality can be improved effectively.

  In addition, the structure which does not have the saw shape of this Embodiment is also applicable to the display apparatus 1. FIG. The surface shape of the transparent cover 17 may be configured by one downward inclined surface. However, in this case, the forward cover protrusion amount is increased. Then, the viewing angle when viewing the display device 1 from an oblique lateral direction is narrowed. On the other hand, this embodiment is advantageous in that a wider viewing angle can be secured.

  Further, in the present embodiment, the downward surface 31 of the transparent cover 17 is a concave curved surface, and as a result, an effect of reducing reflection unevenness can be obtained as described below.

  In the transparent cover 17, the strong external light from above mainly becomes a problem. The reflection of the external light from above is effectively reduced by the jagged surface shape as described above. On the other hand, since the downward surface 31 is provided, external light from below is easily reflected in the viewing direction. The external light from below is, for example, reflected sunlight, and the absolute light quantity is small. However, since the following reflection unevenness occurs, external light also becomes a problem from below. Since uneven reflection is conspicuous, the image quality deteriorates.

  FIG. 6 shows a plurality of transparent covers 17 arranged vertically, together with the amount of reflection of external light from below in the visual recognition direction. Here, the angle of the transparent cover 17 in the longitudinal sectional view is defined as a cover installation angle. In the plurality of transparent covers 17, the cover installation angles are set to be the same in design. However, the cover installation angle may be slightly different between the transparent covers 17 due to the influence of the warp of the entire cover (see FIG. 4).

  Here, it is assumed that the downward surface 31 of the transparent cover 17 is flat. In this case, the amount of reflection of external light from below in the visual recognition direction differs depending on the cover installation angle. For this reason, the amount of reflected light from some of the transparent covers 17 is greater than that of the surrounding transparent covers 17, which may cause uneven reflection. In the example of FIG. 6, the amount of reflected light from one transparent cover 17 is greater than that of the upper and lower transparent covers 17 (dotted line). Such reflection unevenness is easily noticeable even if the amount of reflected light is not large. In particular, unevenness in dark parts tends to be noticeable. Furthermore, in this Embodiment, the transparent cover 17 has a strip | belt shape long in a horizontal direction. For this reason, uneven reflection appears as horizontal streaks and the image quality deteriorates.

  On the other hand, in this Embodiment, the downward surface 31 is comprised by the concave curved surface. That is, the angle of the downward surface 31 gradually changes. In this case, the strong reflection that becomes a problem occurs in a part of the concave curved surface. And this strong reflection appears similarly in the some transparent cover 17 adjacent up and down. That is, it is possible to avoid an increase in the amount of reflection in the viewing direction only with some transparent covers 17. Therefore, reflection unevenness can be reduced. Then, the appearance of horizontal stripes can be avoided, the brightness can be made uniform, and the image quality can be improved.

  As described above, the present embodiment reduces the influence of external light from above by repeatedly providing the transparent cover 17 with the downward surface 31 and the upward surface 33 and is accompanied by the provision of the downward surface 31 in the surface shape. The uneven reflection of external light from below is also reduced by the curved surface configuration provided on the downward surface 31. With a simple configuration in which the surface shape of the transparent cover 17 is devised, it is possible to provide a good image quality in which the influence of not only external light from above but also external light from below is reduced.

  Furthermore, in the present embodiment, the downward surface 31 is a concave curved surface. Thereby, reflection of external light can be reduced as much as possible in the visual recognition direction as compared with the convex curved surface.

  In addition, in the present embodiment, an antireflection layer is provided on the surface of the transparent cover 17. The antireflection layer may have a conventional configuration. By providing the antireflection layer, the influence of external light reflection can be further reduced.

  The display device 1 according to the embodiment of the present invention has been described above. According to the present embodiment, since the transparent cover 17 has a surface shape in which the downward surface 31 and the upward surface 33 appear alternately, the external light reflected in the visual recognition direction by the transparent cover 17 can be reduced, and the bright environment Even underneath, black can be displayed with high contrast and image quality can be improved.

  Moreover, in this Embodiment, the downward surface 31 has faced diagonally downward (it is an inclined surface inclined downward with respect to the horizontal surface), and is comprised by the curved surface. With this configuration, it is possible to reduce the unevenness of reflection of external light from below, make the brightness uniform, and further improve the image quality.

  Therefore, the display device 1 reduces the influence of external light from above by repeatedly providing the downward surface 31 and the upward surface 33 on the transparent cover 17 and lowers due to the provision of the downward surface 31 on the surface shape. The uneven reflection of external light from the light is also reduced by the curved surface configuration. With a simple configuration in which the surface shape of the transparent cover 17 is devised, it is possible to provide a good image quality in which the influence of not only external light from above but also external light from below is reduced.

  Further, in the present embodiment, the downward surface 31 is a concave curved surface, and with this configuration, it is possible to reduce reflection unevenness on the transparent cover 17 while reducing external light reflection as much as possible.

  In the present embodiment, an antireflection layer is provided on the surface of the transparent cover 17, thereby further reducing reflection of outside light and improving image quality.

  From another viewpoint, in the present embodiment, the transparent cover 17 is divided into a plurality of surfaces, and each of the plurality of surfaces reflects incident light in a direction different from the viewing direction. More specifically, the direction or angle of each divided surface is sequentially changed, and the directions of adjacent divided surfaces are alternately set differently. Thereby, the external light reflected in the visual recognition direction by the transparent cover can be reduced, and the image quality can be improved as described above.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and it goes without saying that those skilled in the art can modify the above-described embodiments within the scope of the present invention.

  As described above, the display device according to the present invention can reduce external light reflected in the viewing direction by the transparent cover in front of the light emitting element, has an effect of improving image quality, and is useful as a large display device for outdoor use. It is.

Sectional drawing of the display apparatus in form of this invention The perspective view of the display apparatus in the form of this invention Front view of a display device according to an embodiment of the present invention Front view of transparent cover Diagram showing how external light is reflected by the transparent cover The figure which shows the external light reflection amount to the visual recognition direction in a transparent cover Sectional view of a conventional display device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display apparatus 11 LED element 13 LED board 15 Light-shielding louver 17 Transparent cover 19, 21 Cover holding wall 31 Down surface 33 Up surface

Claims (5)

  A plurality of light emitting elements arranged in a vertical direction and a horizontal direction; and a transparent cover positioned on a front side of the plurality of light emitting elements, the transparent cover having a downward surface facing downward and an upward facing upward A display device having a surface shape in which a surface alternately appears in a vertical direction.   The display device according to claim 1, wherein the downward surface is inclined downward with respect to a horizontal plane and is configured by a curved surface.   The display device according to claim 2, wherein the downward surface is a concave curved surface.   The display device according to claim 1, wherein an antireflection layer is provided on a surface of the transparent cover. A plurality of light emitting elements arranged in the vertical direction and the horizontal direction, and a transparent cover located on the front side of the plurality of light emitting elements,
The transparent cover is divided into a plurality of surfaces, and each of the plurality of surfaces reflects incident light in a direction different from the viewing direction.