CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Republic of Korea Patent Application No. 10-2018-0174101 filed on Dec. 31, 2018, in the Korean Intellectual Property Office, which is incorporated herein in its entirety.

BACKGROUND

Field

The present disclosure relates to a foldable display apparatus, and more particularly, to a foldable display apparatus in which an image display ability of a folding unit can be improved.

Description of the Related Art

Among display apparatuses which are used for a monitor of a computer, a television, or a cellular phone, there are an electroluminescent display apparatus which is a self-emitting device and a liquid crystal display device (LCD) which requires a separate light source.

The electroluminescent display apparatus may include an organic light emitting diode, an inorganic light emitting diode, a quantum-dot diode, a Perovskite LED, a micro LED, and the like, as electroluminescence elements.

Further, recently, a foldable display apparatus which is manufactured by forming a display unit and a wiring line on a flexible substrate such as plastic which is a flexible material so as to be capable of displaying images even though the display apparatus is bent like a paper is getting attention as a next generation display device.

SUMMARY

A disclosed pixel structure of a foldable display apparatus is capable of improving a reliability of pixels disposed in a folding area when the foldable display apparatus is folded.

The pixel structure is advantageous when there is a luminance difference between the pixels disposed in the folding area and the non-folding area.

When a tensile or compressive stress was generated in the folding area of the foldable display apparatus, an electrical stress may be generated in the light emitting layer of the pixel. Further, a parasitic capacitance may increase in at least one of a light emitting layer, a hole injection layer, a hole transporting layer, an electron injection layer, and/or an electron transporting layer due to the electrical stress to cause a luminance difference of the pixels disposed in the folding area and the non-folding area.

Therefore, an object to be achieved by the present disclosure is to provide a foldable display apparatus in which the luminance difference in the folding area and the non-folding area of the foldable display apparatus is reduced.

Objects of the present disclosure are not limited to the above-mentioned objects, and other objects, which are not mentioned above, can be clearly understood by those skilled in the art from the following descriptions.

According to an aspect of the present disclosure, a foldable display apparatus includes: a non-folding area in which some of a plurality of red sub pixels, a plurality of green sub pixels, and a plurality of blue sub pixels is disposed; and a folding area in which the remaining of the plurality of red sub pixels, the plurality of green sub pixels, and the plurality of blue sub pixels is disposed, in which an aperture ratio of the plurality of red sub pixels of the folding area may be lower than an aperture ratio of the plurality of red sub pixels of the non-folding area, an aperture ratio of the plurality of green sub pixels of the folding area may be lower than an aperture ratio of the plurality of green sub pixels of the non-folding area, and an aperture ratio of the plurality of blue sub pixels of the folding area may be lower than an aperture ratio of the plurality of blue sub pixels of the non-folding area.

According to another aspect of the present disclosure, a foldable display apparatus includes: a substrate including a non-folding area and a folding area; and a plurality of sub pixels which is defined in the non-folding area and the folding area on the substrate and include a plurality of light emitting diodes, in which the plurality of sub pixels may be configured to emit at least one color light, and a thickness of the plurality of light emitting diodes of the plurality of sub pixels of the folding area may be larger than a thickness of the plurality of light emitting diodes of the plurality of sub pixels of the non-folding area which emits corresponding color light.

According to still another aspect of the present disclosure, a foldable display apparatus includes: a non-folding area in which some of a plurality of sub pixels including light emitting layers is disposed; and a folding area in which the remaining of the plurality of sub pixels is disposed, in which an aperture ratio of the plurality of sub pixels of the folding area may be lower than an aperture ratio of the plurality of sub pixels of the non-folding area, and a thickness of the light emitting layers of the plurality of sub pixels of the folding area may be larger than a thickness of the plurality of light emitting layers of the plurality of sub pixels of the non-folding area.

Other detailed matters of the exemplary embodiments are included in the detailed description and the drawings.

According to the present disclosure, the thickness of the light emitting layer of the pixel of the folding area and the thickness of the light emitting layer of the pixel of the non-folding area are set to be different to reduce the luminance deviation.

Further, according to the present disclosure, an aperture ratio of the pixel of the folding area and an aperture ratio of the pixel of the non-folding area are set to be different to reduce the luminance deviation.

According to some embodiments, a foldable display apparatus includes a substrate including a folding area and a plurality of sub pixels on the substrate. The plurality of sub pixels include a plurality of red sub pixels, a plurality of green sub pixels, and a plurality of blue sub pixels. At least one of the plurality of red sub pixels, the plurality of green sub pixels, or the plurality of blue sub pixels includes a first subset of sub pixels disposed in an area outside the folding area with a first aperture ratio, and a second subset of sub pixels disposed in the folding area with a second aperture ratio lower than the first aperture ratio.

According to some embodiments, a foldable display apparatus includes a substrate including a folding area and a plurality of sub pixels on the substrate. The plurality of sub pixels include a first subset of sub pixels in an area outside the folding area on the substrate. The first subset of sub pixels are configured to emit a color of light. The plurality of sub pixels also include a second subset of sub pixels in the folding area on the substrate. The second subset of sub pixels are configured to emit the color of light. Each of the plurality of sub pixels include a light emitting diode. A second thickness of the light emitting diodes of the second subset of sub pixels in the folding area is larger than a first thickness of the light emitting diodes of the first subset of sub pixels in the area outside the folding area.

According to some embodiments, a foldable display apparatus includes a substrate including a folding area and a plurality of sub pixels on the substrate. The plurality of subpixels include a first subset of sub pixels in an area outside the folding area on the substrate and a second subset of sub pixels in the folding area on the substrate. The first subset of sub pixels is configured to emit a color of light, and the second subset of sub pixels is configured to emit the color of light. Each of the plurality of sub pixels includes an anode, a cathode, and a light emitting layer between the anode and the cathode. A first capacitance between the anodes and the cathodes of the first subset of sub pixels is greater than a second capacitance between the anodes and the cathodes of the second subset of sub pixels.

The effects according to the present disclosure are not limited to the contents exemplified above, and more various effects are included in the present specification.

