BACKGROUND

Field

Exemplary embodiments of the invention relate generally to a display apparatus, and, more particularly, to an LED display apparatus.

Discussion of the Background

As an inorganic light source, light emitting diodes have been used in various technical fields, such as displays, vehicular lamps, general lighting, and the like. With various advantages of light emitting diodes over conventional light sources, such as longer lifespan, lower power consumption, and rapid response, light emitting diodes have been replacing conventional light sources.

Light emitting diodes have been used as backlight light sources in display apparatuses. However, LED displays that directly display images using the light emitting diodes have been recently developed.

In general, a display apparatus realizes various colors through mixture of blue, green, and red light. In order to display various images, the display apparatus includes a plurality of pixels, each having sub-pixels corresponding to blue, green, and red light, respectively. In this manner, a color of a certain pixel is determined based on the colors of the sub-pixels so that images can be displayed through combination of such pixels.

Since LEDs can emit various colors depending upon materials thereof, a display apparatus may be formed by arranging individual LED chips emitting blue, green, and red light on a two-dimensional plane. However, when one LED chip is arranged in each sub-pixel, the number of LED chips may be increased, which may require excessive time for a mounting process during manufacture.

Since the sub-pixels are arranged on the two-dimensional plane in the display apparatus, a relatively large area is occupied by one pixel that includes the sub-pixels for blue, green, and red light. As such, an area of each LED chip may need to be reduced to arrange the sub-pixels in a restricted area. However, reduction in size of LED chips may cause difficulty in mounting the LED chips, as well as reducing luminous areas of the LED chips.

Meanwhile, a display apparatus that realizes various colors needs to consistently provide high-quality white light. Conventional TVs use an RGB mixing ratio of 3:6:1 to realize the standard white light of D65. More particularly, luminous intensity of red is higher than that of blue, and luminous intensity of green is relatively the highest. However, since conventional LED chips have relatively very high luminous intensity of blue LED compared to that of other LEDs, it is difficult to match the RGB mixing ratio in the display apparatus using LED chips.

In addition, when viewing angles of blue, green, and red light emitted from one pixel are large, interference of light between adjacent pixels may occur, which makes it difficult to realize a clear image quality. However, when a viewing angle of light emitted from one pixel is narrow, light variation is likely to occur due to a difference in luminous intensities between pixels. As such, the viewing angle of light emitted from the pixel may need to be adjusted to an appropriate level.

The above information disclosed in this Background section is only for understanding of the background of the inventive concepts, and, therefore, it may contain information that does not constitute prior art.

SUMMARY

Display apparatuses constructed according to exemplary embodiments of the invention are capable of increasing an area of each sub-pixel in a restricted pixel area.

Exemplary embodiments also provide a display apparatus that is capable of reducing a time associated with a mounting process.

Exemplary embodiments further provide a display apparatus that is capable of easily controlling an RGB mixing ratio.

Exemplary embodiments still provide a display apparatus in which viewing angles of various colors of light emitted within one pixel are adjusted to an appropriate level.

Additional features of the inventive concepts will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concepts.

A display apparatus according to an exemplary embodiment includes a display substrate, a plurality of light emitting devices disposed on the display substrate, a light blocking layer disposed between the light emitting devices, and a transparent layer covering the light emitting devices and the light blocking layer, in which at least one of the light emitting devices includes a first LED sub-unit, a second LED sub-unit disposed on the first LED sub-unit, and a third LED sub-unit disposed on the second LED sub-unit, and the third LED sub-unit is disposed closer to an upper surface of the light emitting device than the first LED sub-unit.

The light blocking layer may be configured to block light by absorbing light emitted from the light emitting device, and the transparent layer may be configured to transmit light emitted from the light emitting device.

The light blocking layer may include a black molding layer.

The first, second, and third LED sub-units may be configured to emit red light, blue light, and green light, respectively.

The first LED sub-unit may include a first light emitting stack, the second LED sub-unit may include a second light emitting stack, the third LED sub-unit may include a third light emitting stack, and each of the light emitting stacks may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer.

The transparent layer may partially cover the light emitting devices.

The transparent layer may be disposed to cross the light emitting devices in one direction.

The transparent layer may have a mesh shape and may include a first transparent layer extending in a lateral direction and a second transparent layer extending in a longitudinal direction, the first transparent layer may cross the light emitting devices, and the second transparent layer may be disposed on the light blocking layer in a region between the light emitting devices.

An upper surface of the light blocking layer may be placed at the same elevation or lower than that of the light emitting device.

The light emitting device may further include a substrate disposed on the third LED sub-unit, and a difference in refractive indices between the transparent layer and air may be less than a difference in refractive indices between the substrate and the first conductivity type semiconductor of the third light emitting stack.

The light emitting device may further include a substrate disposed on the third LED sub-unit, and the upper surface of the light blocking layer may be placed at a lower elevation than that of an upper surface of the substrate to expose at least a portion of a side surface of the substrate.

The light blocking layer may be placed a lower elevation than that of an upper surface of the third light emitting stack to expose at least a portion of a side surface of the third light emitting stack.

The light emitting device may further include a first bonding layer interposed between the first LED sub-unit and the second LED sub-unit, and a second bonding layer interposed between the second LED sub-unit and the third LED sub-unit.

The light emitting device may further include a first connection electrode electrically connected to the first LED sub-unit, a second connection electrode electrically connected to the second LED sub-unit, a third connection electrode electrically connected to the third LED sub-unit, and a fourth connection electrode commonly electrically connected to the first, second, and third sub-units.

The display apparatus may further include a circuit board interposed between the display substrate and the light emitting device, in which the first, second, third, and fourth connection electrodes may be bonded to the circuit board, and the light blocking layer may be disposed on the circuit board.

The first connection electrode, the second connection electrode, and the third connection electrode may be electrically connected to the second conductivity type semiconductor layers of the first light emitting stack, the second light emitting stack, and the third light emitting stack, respectively, and the fourth connection electrode may be commonly electrically connected to the first conductivity type semiconductor layers of the first, second, and third light emitting stacks.

The light emitting device may further include first, second, and third lower contact electrodes contacting the second conductivity type semiconductor layers of the first, second, and third light emitting stacks, respectively, and a first insulation layer having first, second, and third contact holes partially exposing the first, second, and third lower contact electrodes, the first insulation layer may have sub-contact holes disposed on the first conductivity type semiconductor layers of the first, second, and third light emitting stacks, and the sub-contact holes may be spaced apart from one another.

The light emitting device may further include first, second, and third pads overlapping with the first, second, and third contact holes and a fourth pad overlapping with the sub-contact holes, and the first, second, third, and fourth connection electrodes may be electrically connected to the first, second, third, and fourth pads, respectively.

A display apparatus according to another exemplary embodiment includes a display substrate, a plurality of light emitting devices disposed on the display substrate, a black molding layer disposed between the light emitting devices to block light emitted from the light emitting devices, and a transparent layer at least partially covering the light emitting devices and configured to transmit light emitted from the light emitting devices, in which at least one of the light emitting devices includes a first LED sub-unit, a second LED sub-unit disposed on the first LED sub-unit, and a third LED sub-unit disposed on the second LED sub-unit, and the third LED sub-unit is disposed closer to an upper surface of the light emitting device than the first LED sub-unit.

An upper surface of the black molding layer may be placed at the same elevation or lower than those of the light emitting devices.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

