The present application claims priority from Japanese application JP2015-069500 filed on Mar. 30, 2015, the content of which is hereby incorporated by reference into this application.
1. Field of the Invention
The present invention relates to a display device.
2. Description of the Related Art
Some liquid crystal display devices control the orientation of liquid crystals using switching elements, such as transistors, to display images. Some display panels, such as liquid crystal panels filled with liquid crystals, each include, for example, a glass substrate. JP 2006-024530 A discloses a display device that includes a first glass substrate, a second glass substrate disposed facing the first glass substrate, and a plastic film disposed on at least one of the first and second glass substrates.
Some of the display devices each have a display area and a frame area. If the display panel were formed with a flexible substrate and folded back to narrow the frame area, the display area might be strained.
Therefore, it is an object of the present invention to provide a narrow frame display device having a less strained display area.
A display device according to an aspect of the present invention includes a first insulating substrate, a second insulating substrate, and a sealant. The first insulating substrate is flexible and has a display area provided with an image display function. The second insulating substrate is smaller than the first insulating substrate and covers the display area. The sealant is disposed around the display area and fixes the first and second insulating substrates together. The first insulating substrate has a bent portion that is adjacent to an edge of the second insulating substrate and a return portion that is folded back away from the second insulating substrate.
The following describes embodiments of the present invention with reference to the accompanying drawings. The disclosure herein is merely an example, and appropriate modifications coming within the spirit of the present invention, which are easily conceived by those skilled in the art, are intended to be included within the scope of the invention as a matter of course. In some drawings, the widths, the thicknesses, the shapes, and other characteristics of various parts are schematically shown for clarity of illustration, as compared to actual configurations. However, such schematic drawings are merely examples and are not intended to limit the present invention. In the present specification and drawings, some elements identical or similar to those previously shown are denoted by the same reference signs as the previously-shown elements, and thus are not described in detail herein as appropriate.
The display panel 10 has a flexible printed circuit (FPC) 23 joined to an edge of the first insulating substrate 20. The flexible printed circuit 23 has a driver integrated circuit (IC) 24 mounted thereon. The flexible printed circuit 23 may have other electronic circuits mounted thereon. The sealant 22 may double as a spacer that keeps a constant gap between the first insulating substrate 20 and the second insulating substrate 21. When the sealant 22 is also used as a spacer, the distance between the first insulating substrate 20 and the second insulating substrate 21 can be adjusted by selecting the thickness of the sealant 22.
The display and 10 has the display area 11 provided with the image display function. The display area includes pixels that each emit light of one of the colors RGB and displays full color. Light emission of each pixel is controlled by control signals sent out from the driver IC 24. The display panel 10 according to this embodiment is a liquid crystal display panel. The display panel 10 is not limited to a liquid crystal display panel and may be an organic electroluminescent (EL) display panel or a quantum dot display panel.
The display panel 10 according to this embodiment is folded back on itself along the return line A and away from the visible side of the display area 11.
The display panel 10 according to this embodiment includes liquid crystals 25 filled into the region enclosed by the first insulating substrate 20, the second insulating substrate 21, and the sealant 22. The orientation of the liquid crystals 25 is electrically controlled by pixel electrodes disposed in the first insulating substrate 20 to pass polarized light entering from the first insulating substrate 20 through themselves or to change the polarization. To precisely control the orientation of the liquid crystals 25, at is important to keep the distance (cell gap) between the first insulating substrate 20 and the second insulating substrate 21 constant throughout the display area 11.
In the display panel 10 according to this embodiment, the first insulating substrate 20, which is a flexible substrate, allows an edge of the display panel 10 to be folded back on itself to narrow the frame, and the second insulating substrate 21, which is a rigid substrate, reduces strain of the display area 11. Reduction of strain of the display area 11 allows the cell gap of the liquid crystals 25 to be kept uniform throughout the display area 11, thus providing high image display quality.
Also in the display panel 10 according to this embodiment, the return portion 31, on which an electronic component required to drive the display panel 10 is disposed, allows the electronic component to be located outside the frame area, thus narrowing the frame.
Right above the lower alignment film 60, an upper alignment film 60 is formed. The gap between the lower and upper alignment films 60 is filled with the liquid crystals 25, and the alignment films 60 and the liquid crystals 25 are sealed around their periphery by the sealant 22. On the upper alignment film 60, an overcoat layer 61 is formed of a resin material. In the overcoat layer 61, a black matrix 62, a blue color filter 63, and a red color filter 64 are formed. In addition to these, although not shown, a green color filter is formed, and thus RGB pixels are formed. Moreover, a counter substrate 65 provided with the second polarizing plate 66 is stacked on the black matrix 62 and each color filter. The second insulating substrate 21, which is disposed on the liquid crystals 25, is thus formed.
Outside the sealant 22 (outside the display area 11), a lead. 67 is formed of metal on the gate insulating film 52 and is joined to the above-described flexible printed circuit 23. The lead 67 transmits electrical signals from the driver IC 24 and applies a power supply potential to the flexible printed circuit 23.
A through hole is formed through the planarization film. 81 to the source electrode 79. A contact electrode 82 is then formed of a conductive material, including metal, so as to be electrically coupled to the source electrode 79 through the through hole. On the planarization film 81, a capacitor electrode 86 is formed of a conductive material, including metal. A sixth insulating film 83 is formed to cover both the contact electrode 82 except for its bottom and the capacitor electrode 86. A lower electrode 84 is then formed of a conductive material, including metal, so as to be electrically coupled to the source electrode 79 via the contact electrode 82. An inter-pixel insulating film 85, which is an insulating film, is formed to cover part of the lower electrode 84. The area where the inter-pixel insulating film 85 is formed is to be a non-light-emitting area, whereas the area where no inter-pixel insulating film 85 is formed and where the lower electrode 84 is formed is to be a light-emitting area.
On the inter-pixel insulating film 85 and the lower electrode 84, an organic layer 87 including an organic light-emitting layer that emits white light is formed. In this modification, the organic layer 87 is formed throughout the display area 11, but an organic layer may be colored, for each pixel, to emit red, green, or blue light. On the organic layer 87, an upper electrode 88 is formed of a transparent conductive material, such as ITO or indium zinc oxide (IZO). The lower electrode 84, the organic layer 87, and the upper electrode are a light-emitting element (organic EL element) including an organic light-emitting layer, which is stacked on the display area 11. On the upper electrode 88, a seventh insulating film 89 is formed, and a sealing film 90 is then formed. Right above the inter-pixel insulating film 85, a black matrix is formed on the sealing film 90. Right above the light-emitting area, a blue color filter 92 and a red color filter 93 are also formed on the sealing film 90. Although not shown, a green color filter is also formed, and thus pixels that have luminescent colors of RGB are formed. On the black matrix 91, the blue color filter 92, and the red color filter 93, a counter substrate 94 is formed of, for example, glass in this modification, the counter substrate 94 is the second insulating substrate 21.
Outside the display area 11, the upper electrode 88 and the contact portion of a ground electrode 95 as well as the TFT are formed. The upper electrode 88 is maintained at a potential (ground potential) common to all the pixels. Outside the sealant 22, a lead 96 is formed of metal on the fifth insulating film 78 and is electrically coupled to the flexible printed circuit 23 at an area not shown.
The display panel according to this embodiment, in which the backlight 40 is disposed on the side opposite to the visible side of the display area 11, makes use of the space inside the bent portion 30 to form the liquid crystal display device without increasing the thickness of the display panel.
A touch screen flexible printed circuit 42 is electrically coupled to an edge of the touch screen 41 according to this embodiment, and a touch screen driver IC 43 is mounted on the touch screen flexible printed circuit 42. The touch screen 41 is folded back to cover the return portion 31, at the same position as the bent portion 30. The touch screen flexible printed circuit 42 is disposed over the flexible printed circuit 23 and the driver IC 24. Use of such a configuration allows even the frame of a display device with a touch screen to have a narrow frame.
Those skilled in the art can appropriately modify the design of the display device 1 described above as embodiments of the present invention and implement other display devices, and all such display devices also fall within the scope of the invention as long as they come within the spirit of the invention. For example, two or more sides of the first insulating substrate may be folded back so that the first insulating substrate has a plurality of return portions.
Various variations and modifications can be conceived by those skilled in the art within the spirit of the present invention, and it will be understood that all such variations and modifications also fall within the scope of the invention. For example, those skilled in the art can appropriately modify the above-described embodiments by addition, deletion, or design change of components, or by addition, omission, or condition change of steps, and all such modifications also fall within the scope of the invention as long as they come within the spirit of the invention.
It will also be understood that other effects produced by the aspects described in the embodiments, which are apparent from the description herein or can be appropriately conceived by those skilled in the art, are produced by the present invention as a matter of course.
While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claim cover all such modifications as fall within the true spirit and scope of the invention.
Number | Date | Country | Kind |
---|---|---|---|
2015-069500 | Mar 2015 | JP | national |