Display device with optical reflecting layer for reduction of screen door effect

A display device includes a thin film transistor (TFT) substrate, an overcoat layer on an upper substrate, and a reflective layer on the overcoat layer. The TFT substrate covers a light guide plate and includes TFTs configured to drive pixels of the display device. The reflective layer on the overcoat layer reflects light output from the light guide plate towards a viewing surface of the display device. The reflected light overlaps a portion of a non-active area between the active areas of pixels of the display device in at least one dimension.

BACKGROUND

This disclosure relates generally to display devices, in particular to reducing a screen door effect for display devices.

Electronic displays include a plurality of pixels, which may each include a plurality of sub-pixels (e.g., a red sub-pixel, a green sub-pixel, etc.). Arrangement of individual sub-pixels may affect the appearance and performance of an electronic display device. A sub-pixel includes both an emission (i.e., active) area and a non-emission (i.e., non-active) area, and the fill factor of the sub-pixel describes the ratio of light emission area versus total area of the sub-pixel. The non-emission areas thus limit the fill factor of each sub-pixel. Additionally, some arrangements of sub-pixels may increase fixed pattern noise under certain conditions. For example, magnification of a pixel may result in non-emission areas between individual sub-pixels of the pixel becoming visible to the user, resulting in a “screen door” pattern (i.e., an increase in fixed pattern noise) in an image presented to a user. Such a phenomena is known as a screen door effect, in which the non-emission areas separating subpixels of a display device become visible in the displayed image.

Head-mounted displays (HMDs) can include an electronic display. HMDs may also include optics to magnify images from the electronic display to increase a field of view to a user. Thus, HMDs with display devices may have problems with a screen door effect, in which non-active areas separating subpixels or pixels of a display device become visible in the displayed image.

SUMMARY

Embodiments relate to a display device with a reflective layer to reduce a screen door effect for the display device. An overcoat layer on an upper substrate includes recessed areas, and the reflective layer covers at least a portion of the recessed areas. The reflective layer reflects light from sub-pixels of the display device to cover a portion of a non-active area between active areas of sub-pixels of the display device. The reflective layer can be used in place of a black matrix layer (e.g., absorptive layer) or in conjunction with a black matrix layer (e.g., absorptive layer) of the display device.

The reflective layer reflects a portion of light output from the lower structure to cover a portion of a non-active area between active areas of the sub-pixels. The lower structure includes a plurality of sub-pixels. Each sub-pixel of the lower structure may correspond to a liquid crystal cells and/or light sources.

A portion of the light from the lower structure is incident on the reflective layer is reflected to cover a portion of a non-active area between active areas of the sub-pixels. Thus, light from a pixel of a display device with the reflective layer can cover a larger area compared to light from a pixel of a display device without the reflective layer. The display device with the reflective layer increases a fill factor of the pixels of the display device and reduces a screen door effect of the display device. The display device with the reflective layer can also increase an efficiency of the display device, as light that may be trapped within the display device could be reflected by the reflective layer towards a viewing user.

In some embodiments, a display device includes a thin film transistor (TFT) substrate (i.e., lower substrate), an overcoat layer on an upper substrate, and a reflective layer on the overcoat layer. The lower substrate covers a light guide plate and includes TFTs to drive pixels of the display device. The reflective layer reflects light output from the light guide plate towards a viewing surface of the display device. The reflected light overlaps a portion of a non-active area between active areas of pixels of the display device in at least one dimension.

In some embodiments, a display device includes a lower substrate, a first and a second overcoat layer on an upper substrate, and a reflective layer between the first overcoat layer and the second overcoat layer. The lower substrate includes TFTs to drive pixels of the display device to emit light. The reflective layer reflects light emitted by the pixels of the display device to overlap a portion of a non-active area between active areas of pixels of the display device in at least one dimension.

DETAILED DESCRIPTION

Disclosed is a display device with an optical reflective layer for screen door reduction. The display device includes a reflective layer to reflect light emitted from sub-pixels of the display device towards a viewing surface of the display device to reduce a screen door effect. The display device may have a target viewing distance (i.e., a minimum distance from a display to view content). A screen door effect occurs when dark or non-active areas separating sub-pixels in a display device is visible to a viewing user in an image displayed by the display device at the target viewing distance.

The display device with a reflective layer may have an increase in fill factor of over a display device without a reflective layer. A fill factor of a sub-pixel of a display device describes the ratio of light emission area versus total area of the sub-pixel (e.g., emissive area and non-emissive area of the sub-pixel). A display device with a reflective layer may have an energy enhancement of approximately 20 percent and over a display device without a reflective layer. For example, a reflective layer may increase an effective active area of a sub-pixel by reflecting light from a sub-pixel of a lower structure to a portion of a non-active area of the sub-pixel. The reflected light could be light that would have been spread over a larger angle and/or trapped in the display device that is now allowed to exit the display device in a non-active area corresponding to the sub-pixel. Thus, as the non-active area of the sub-pixel appears to be reduced with the reflected light, and the effective active area of the sub-pixel increased, a fill factor of the display device is increased. The light from the display device with a reflective layer may also be more collimated in comparison to light from a display device without a reflective layer.

Display Device Architecture

FIG. 1is a cross sectional view of a portion of a display device100with an optical reflecting layer124and three overcoat layers112,120, and126, in accordance with one or more embodiments. In other embodiments, the display device100comprises additional or fewer components than those described herein. Similarly, the functions can be distributed among different components and/or layers in a different manner than is described here.

The display device100ofFIG. 1is a LCD device and includes a lower structure101, an overcoat layer122, a reflective layer124, an overcoat layer126, an upper substrate128, and an upper polarizer130. The reflective layer124reflects light output from the lower structure101towards a viewing surface122of the display device100to overlap a non-active area164of a sub-pixel160to reduce a screen door effect of the display device100. In the cross sectional view shown inFIG. 1, the reflective layer124is positioned between rows of sub-pixels in display device100. An orthogonal cross section may also include a reflective layer between columns of sub-pixels of the display device. Alternatively, the reflective layer may not be between columns of sub-pixels, and a black matrix layer may be between columns of sub-pixels in the display device. The lower structure101includes a light source102, a light guide plate104, a lower polarizer106, a lower substrate108, a TFT layer109, a liquid crystal layer110, an overcoat layer112, and a color filter layer114. The lower structure101includes a plurality of sub-pixels corresponding to liquid crystal cells. In other embodiments, the lower structure101may include a plurality of active emissive elements. For example, instead of the lower structure101including a light source102and light guide plate104, the lower structure101may include an array of active light sources. The light sources may be, e.g., vertical cavity surface-emitting lasers (VCSELs), organic light emitting diodes (OLEDs), light emitting diodes (LEDs), or some combination thereof. Each of the active light sources may correspond to a plurality of sub-pixels. In some embodiments, each of the active light sources may correspond to a single sub-pixel, and the lower structure101may not include a liquid crystal layer.

The light source102is an electrical device that is configured to emit light in a wavelength range. In some embodiments, the wavelength range includes all the wavelengths of visible light (e.g., 390-760 nm). For example, the light source may be a white LED or OLED that emits white light (e.g., contains all wavelengths in range of 390-760 nm at a same or similar intensity). Alternatively, the light source102may be a blue LED or a blue OLED that emits blue light (e.g., 450-495 nm) to be used with a quantum dot layer (e.g., film containing red and green quantum dots) to convert some of the emitted light to red light and green light so that the combination of colored light produces white light. Alternatively, the light source102may include a plurality of light sources (e.g., red, green, and blue LEDs or OLEDs) such that the combined emission from the light sources produces white light.

The light guide plate104is a plate that is configured to receive light from a first surface of the plate and to direct the received light to exit uniformly over a second surface of the plate. A side surface of the light guide plate104is coupled to the light source102. The light guide plate104receives light emitted from a light source102from the side surface of the light guide plate104and directs the received light to exit uniformly over a top surface of the light guide plate104. The light guide plate104may be made of acrylic, glass, or some other material that can confine light from the light source102. A surface (e.g., bottom or top) of the light guide plate104includes a pattern to direct the received light to exit uniformly over the top surface of the light guide plate104. The pattern may be a grating formed by etching lines on the surface of the light guide plate104. A spacing of the etched lines closer to the light source102is greater than a spacing of etched lines further away from the light source. That is, etched lines further away from the light source102are spaced more closely together to produce a more uniform spreading of the light exiting the top surface of the light guide plate104. Alternatively, a pattern may be printed with diffusive ink on a surface of the light guide plate104, the printed pattern being denser as a distance increases from the light source102. In some embodiments, a surface of the light guide plate is reflective. For example, a bottom surface of the light guide plate may be covered with a reflective layer (e.g., metal layer) to be 100% (or close to, effectively 100%) reflective. The reflective layer reflects light emitted from the light source102towards a top surface of the light guide plate104to exit the light guide plate104.

In the embodiment shown inFIG. 1, the display device100is an edge-lit LED backlight. That is, the light source102is formed on an edge of the display device100and the light guide plate104directs light emitted from the light source102to exit uniformly out of a top surface of the light guide plate104. In other embodiments, the display device100can be a back-lit LED, in which a full array of white LEDs (or red, green and blue LEDs) replace the light source102and light guide plate104. A single white, red, green, or blue LED may correspond to multiple sub-pixels, and a diffusing plate may cover the array of LEDs to uniformly spread the emitted light. In some embodiments, a single white, red, green, or blue LED (or OLED) may correspond to a single sub-pixel.

The lower polarizer106is a polarizing filter configured to transmit light of a first polarization. The lower polarizer106includes a top surface and a bottom surface. The bottom surface of the lower polarizer106faces a top surface of the light guide plate104and receives uniform light from the top surface light guide plate104. The lower polarizer106allows light of a first polarization to pass through the polarizing filter to exit a top surface of the polarizing filter.

A lower substrate108is a transparent material such as glass or plastic configured to transmit light and support other layers that are deposited and processed on it. The lower substrate108includes a top surface and a bottom surface. The bottom surface of the lower substrate108faces a top surface of the lower polarizer106and receives light of a first polarization exiting the top surface of the lower polarizer106. The lower substrate108transmits light of a first polarization to exit out a top surface of the lower substrate108.

In the illustrated embodiment, the TFT layer109provides power to liquid crystal cells in the liquid crystal layer110. A liquid crystal cell is liquid crystal material in a corresponding sub-pixel of the display device100. The TFT layer109is deposited on the top surface of the lower substrate108. The TFT layer109may include semiconductor material (e.g., amorphous silicon, polysilicon, oxide semiconductor, organic semiconductor), source, drain, and gate material (e.g., metal or conductive oxide), and insulating materials (e.g., oxide, high-k dielectric material, parylene). The TFT layer109may include a planarizing material (e.g., overcoat layer) to cover the plurality of TFTs formed on the lower substrate108and form a planar top surface of the TFT layer109. In some cases, an overcoat layer is formed as a top surface the TFT layer109and is further for alignment of a liquid crystal material in a liquid crystal layer110adjacent to the TFT layer109. The TFT layer110includes a plurality of driving TFTs that are configured to provide power to one or more liquid crystal cells in the liquid crystal layer114. The TFTs includes a conductive anode and cathode that may be part of the TFT layer109and/or the liquid crystal layer110. In some embodiments, some or all of the TFTs are made of opaque materials, and formed in regions of the display device100corresponding to a non-active area164of the display device100. In some embodiments, some or all of the TFTs are composed of materials that are at least partially transparent to light emitted by the emission devices435. For example, Indium Tin Oxide or some other transparent conductive material may be used instead of opaque metals in the TFTs.

The liquid crystal layer110includes liquid crystal material that changes in orientation responsive to application of an electric field. The liquid crystal layer110has a top surface and a bottom surface. A bottom surface of the liquid crystal layer110is formed on a top surface of the TFT layer109. The lower substrate108and TFT layer109transmits light of the first polarization (exiting the lower polarizer106) to a bottom surface of the liquid crystal layer110. An electric field may be applied across electrodes of a one or more sub-pixels to change an orientation of the liquid crystal material in a corresponding portion of the liquid crystal layer110. Changing the orientation of the liquid crystal material can change the polarization of light that is transmitted through the liquid crystal layer110. In the example shown inFIG. 1, light of a first polarization incident on a bottom surface of the liquid crystal layer110is changed to light of a second polarization (e.g., by applying an electric field to the liquid crystal layer110) so that light of the second polarization exits the top surface of the liquid crystal layer110. In this way, a polarization of light exiting the top surface of the liquid crystal layer110can be controlled by application of an electric field to include different amounts of light of a second polarization.

An overcoat layer112is a transparent material for planarizing a surface. In this embodiment, the overcoat layer covers a color filter layer114to provide a planar surface for liquid crystal material. The overcoat layer112can be made of an acryl material. A bottom surface of the overcoat layer112is a planar surface facing a top surface of the liquid crystal layer110. The bottom surface of the overcoat layer112receives light of a second polarization exiting the liquid crystal layer110. The received light of a second polarization exits a top surface of the overcoat layer112.

A color filter layer114includes a plurality of color filters114a,114b, and114c. Although only three color filters are shown in the illustrated portion of the display device100ofFIG. 1, the color filter layer114includes many more color filters (e.g., a color filter for each sub-pixel of the display device100). The color filters114a,114b, and114cshown in this cross section taken in a column direction (e.g., y-direction) of a display device100would correspond to color filters of a same color (e.g., all red in a same column of sub-pixels), and color filters in an adjacent cross section (e.g., neighboring column of sub-pixels in a y-direction) can correspond to color filters of a different color (e.g., all green or all blue). For cross sections shown along an x-direction, the adjacent color filters may correspond to different colors (e.g., red, green, and blue color filters). A bottom surface of the color filter layer114faces a top surface of overcoat layer112to receive light of a second polarization. Each color filter114a,114b,114callows wavelengths of light in a particular range (i.e., color band) to be transmitted through the filter and blocks wavelengths of light outside of the color band from being transmitted through the filter. The color filters114a,114b, and114cmay be associated with a same color band (e.g., red color band). Alternatively, the color filters114a,114b, and114cmay be associated with a first color band, a second color band, and a third color band, respectively (e.g., red, green, and blue color band). Each color filter may be formed by depositing and patterning a colored photoresist that contains absorptive pigments. An absorptive pigment from a color filter absorbs light from wavelength range outside of the color band of the color filter, preventing the light outside the color band from being transmitted through the color filter. The light exiting the color filter layer114is light of a second polarization in a color band of the color filter.

The overcoat layers122and126are transparent materials that are configured to transmit light, and the reflective layer124reflects light150output from the lower structure101towards a viewing surface180of the display device100. The first over coat layer122provides a shape for the reflective layer124. The overcoat layer126and provides a planar surface for formation of the color filter layer114. The overcoat layer122is formed on the upper substrate128and includes a plurality of recessed areas, and the reflective layer124covers the recessed areas. The recessed areas in the overcoat layer122forms an angle with a surface of the overcoat layer122. Similarly, the reflective layer124covering the recessed areas also forms a same angle with the surface of the overcoat layer122. As such, the recessed areas of the overcoat layer122provides a shape for the reflective layer124. An overcoat layer126covers the reflective layer124in the recessed areas of the overcoat layer122and forms a same planar surface with the overcoat layer122. The overcoat layer122and the overcoat layer126may be three to fifteen micrometers or more in thickness. The overcoat layer122and the overcoat layer126provide a planar surface so that the color filter layer114can then be easily formed on the planar surface. A bottom surface of the overcoat layer122faces a top surface of a color filter layer114. The overcoat layer112covers the color filter layer114to form a planar surface for the liquid crystal layer110, as previously mentioned. The overcoat layers122,126, and112may be made of acryl or other transparent material, and may have an index of refraction that is the same as the index of refraction of the upper substrate128. In some embodiments, the overcoat layer122, overcoat layer120, and overcoat layer112may be referred to as the first overcoat layer, second overcoat layer, and third overcoat layer respectively.

The reflective layer124reflects light output from the lower structure101to reduce a screen door effect of the display device100. The reflective layer124is formed in the recessed areas to form a similar shape of the recessed areas. A surface124aof the reflective layer124forms a same angle as a recessed area to a planar surface of the overcoat layer122and the overcoat layer126. A surface124bof the reflective layer124is parallel to a surface of the upper substrate128. The surface124bmay act as a black matrix for the display device100to prevent light leakage (e.g., preventing stray light from exiting the display device100) in the non-active area of the display device100. A black matrix is an opaque layer that prevents light from leaking in a non-active area of a display device. The black matrix can be an absorptive coating including absorptive particles to absorb light, a reflective layer that reflects light, or some combination thereof. The reflective layer124can be made of any material that is reflective to the light from the lower structure101. For example, the reflective layer124may be a metal and/or metal film (e.g., silver, aluminum, gold, etc.).

The upper substrate128is a transparent material such as glass or plastic and includes a top surface and a bottom surface. The upper substrate128and the overcoat layers112,120, and126may have a same index of refraction. The bottom surface of the upper substrate128faces a top surface of the overcoat layer126and receives the reflected light transmitted through the overcoat layer126.

The upper polarizer130is a polarizing filter configured to transmit light of a second polarization. The upper polarizer130covers a top surface of the upper substrate128and receives the reflected light transmitted through the upper substrate128. The upper polarizer130allows light of a second polarization to pass through the polarizing filter to exit an upper surface of the polarizing filter. A second polarization of the upper polarizer130is different from the first polarization of lower polarizer106. The upper and lower polarizers130and106may be a same type of polarizing filter, and the axes of transmission of the two polarizing filters may be oriented perpendicular to each other in the display device100.

In some embodiments, the upper polarizer130may act as an encapsulation layer. In alternate embodiments, the display device100may further include the encapsulation layer on formed on top of the upper polarizer130. The encapsulation layer protects the display device100from environmental factors (e.g., dust, water, etc.). The encapsulation layer is transparent to the light emitted from the display device100, and may be formed from, e.g., transparent glass, sapphire, plastic, polarizer, some other material that is transparent to the light emitted by emission devices, or some combination thereof.

Light150aexits the lower structure101out of a top surface of a color filter layer114. The bottom surface of the overcoat layer122receives light150aof a second polarization in a color band of a corresponding color filter exiting the lower structure101. The light150aof a second polarization in a color band is transmitted through the overcoat layer126to be incident on surface124aof the reflective layer124. The reflective layer124reflects the light150btowards an upper surface of the overcoat layer122. The reflected light150covers a portion of a non-active area164of the sub-pixel160.

A sub-pixel160includes an active area162and a non-active area164. The active area162corresponds to an area of sub-pixel160in which light is emitted from the lower structure101. The non-active area164corresponds to an area of the sub-pixel160in which light is blocked from exiting the lower structure101. In some embodiments, the non-active area164of a display device100may include a black matrix, TFTs (e.g., driving transistors), or wiring that is opaque or not transparent. The reflective layer124reflects light (e.g. reflected light150) that is output from the lower structure101between adjacent recessed areas of the overcoat layer122.

In some embodiments, a black matrix layer (not shown) may be formed in between active areas of sub-pixels to absorb light to prevent light from leaking in the non-active area. For example, the color filter layer114may include a black matrix layer. The black matrix layer is an opaque layer that prevents light from leaking in the non-active area. The black matrix can be an absorptive material that is a combination of different types of color filters (RGB) or be a black photolithographic material including black pigment for absorbing white light. In other embodiments, this black matrix layer (e.g., absorptive layer) may be formed to cover the reflective layer124in place of or before the overcoat layer126is formed. Alternatively, a black matrix layer could replace the portion124bof the reflective layer124.

The embodiment inFIG. 1is an LCD device, but in other embodiments, the display device can be a different type of display device. For example, the display device may be a display device in which the intensities of each sub-pixels are controlled by drive TFTs. The sub-pixels may be a white light source which uses the color filter layer to filter emitted white light to light in a color band. The sub-pixels may be a blue light source with a color filter layer including a quantum dot color filter for red and green sub-pixels (e.g., red and green quantum dots for converting blue light to red and green light). Accordingly, in some embodiments, the display device may not include one or more of the following: the light source102, the light guide plate104, the lower polarizer106, the liquid crystal layer110, and the upper polarizer130.

FIG. 2is a cross sectional view of a portion of a display device200with an optical reflecting layer124and two overcoat layers, in accordance with one or more embodiments. The display device200ofFIG. 2is the same as the display device100ofFIG. 1except the overcoat layer226ofFIG. 2replaces the overcoat layers126and112ofFIG. 1. The overcoat layer226covers the color filter layer114(e.g., color filters114a,114b, and114c) and the reflective layer124to form a planar surface. The reflective layer124reflects light output from the lower structure202between adjacent recessed areas of the overcoat layer122. In some embodiments, the overcoat layer122and overcoat layer126may be referred to as the first overcoat layer and second overcoat layer respectively.

FIG. 3Ais a top view of a portion of a display device300with a continuous optical reflecting layer324, in accordance with one or more embodiments. The display device300includes a plurality of sub-pixels. The portion depicted inFIG. 3Adepicts only three pixels301(e.g., one in each row). However, the display device300includes many pixels (e.g., millions of pixels). Each pixel301comprises a blue sub-pixel (sub-pixel B), a green sub-pixel (sub-pixel G), and a red sub-pixel (sub-pixel R). Each sub-pixel B, G, and R includes an active area310and a non-active area320. A continuous optical reflecting layer324is between the active areas310of the sub-pixels B, G, and R. The reflective layer324includes a portion324aand a portion324b. The portions324aand324bofFIG. 3may correspond to portions124aand124bofFIGS. 1 and 2, which are a cross section along a column direction (e.g., y direction). The reflective layer324comprising portions324aand324bare in between rows of pixels301or sub-pixels of a same color.

In the embodiment ofFIG. 3, the reflective layer324may cover the portion of the display device300indicated as portion330shown in between the active areas310of the sub-pixels R, G, and B of different colors (e.g., sub pixels in a same pixel). In the embodiment shown inFIGS. 1 and 2, a reflective layer324does not cover a portion of the display device300indicated as portion330in between the sub-pixels R, G, and B of a same pixel. Instead, a black matrix layer covers the portion330of the display device.

In some embodiments, a black matrix layer (e.g., absorptive layer) is used in place of or in conjunction with a portion324b. In some embodiments, a black matrix layer (e.g., absorptive layer) is used in place of or in conjunction with the portion330between the active area310of sub-pixels B, G, and R of a same pixel. The reflective layer324amay be in an area between the active area of adjacent sub-pixels of a same color and a black matrix may be in an area310between active areas of sub-pixels of different colors.

A display device with a continuous reflective layer can have a lower resistance than a display device with a discontinuous reflective layer, and may have problems with electrostatic discharge. Additionally, a display device with a continuous reflective layer may have a greater risk of statistic mura (e.g., luminance non-uniformity) in the display device.

FIG. 3Bis a top view of a portion of a display device350with a discontinuous optical reflecting layer352, in accordance with one or more embodiments. In one embodiment, the reflective layer352in regions between the active areas of adjacent sub-pixels of a same color. A black matrix or a reflective layer354is in regions between the active areas of sub-pixels of a different color. A reflective layer352that is discontinuous in structure may reduce the risk of the display device having problems with electrostatic discharge and mura. The reflective layer352may be made discontinuous in a region of the reflective layer that vertically overlaps a portion of the lower substrate including TFTs or opaque elements. In this way, the reflective layer352may be discontinuous in regions that may not require the reflective layer to function as a black matrix (e.g., in regions of the lower substrate that are already light-blocking).

FIG. 3Cis a top view of a portion of a display device with an optical reflecting layer illustrating an effective active area380. The effective active area380may correspond to the effective active area168shown inFIGS. 1 and 2. The active area310may correspond to active area162shown inFIGS. 1 and 2. The effective active area380is increased in a column direction from active area310.

FIG. 4illustrates an example process for fabricating an optical reflecting layer of a display device, in accordance with one or more embodiments. This example is merely illustrative, and other processes may be used to form the optical reflecting layer of the display device. Likewise, embodiments may include different and/or additional steps, or may perform the steps in different orders.

An overcoat layer122is formed410on the upper substrate128. A mask is formed420on the overcoat layer122. The mask may be made by depositing photoresist, exposing photoresist through a photo mask, and developing the photoresist. The overcoat layer122is etched430to form recessed areas in the overcoat layer122. A reflective layer124is deposited over the mask, the overcoat layer122, and the upper substrate128. The mask is removed so that a reflective layer124remains440in the recessed areas in the overcoat layer122but is absent from other surfaces of the overcoat layer122. An overcoat layer120is deposited450over the reflective layer124to form a planar surface with the overcoat layer122. Thus, the optical reflecting layer is fabricated on an upper substrate128of a display device100. Subsequent processing steps on the upper substrate128after the formation of the optical reflecting layer can include the formation of the color filter layer114and an overcoat layer112to form a planar surface to face a liquid crystal layer110. The upper substrate128including the reflective layer124can be used in an LCD display as shown, for example, inFIG. 1. The reflective layer124reflects light output from the lower structure101to overlap a non-active area of a sub-pixel to reduce a screen door effect of the display device.

FIG. 5illustrates a reduction in a screen door effect of a display device with an optical reflecting layer, according to one or more embodiments.FIG. 5depicts a similar configuration toFIG. 3CexceptFIG. 5is a representation a simulation result of a display device with a reflecting layer in comparison to a display device without a reflecting layer.FIG. 5includes three rows of pixels that each have three sub pixels (e.g., B, G, and R). In a display device without a reflecting layer (e.g., left image), a height of an active area of a sub-pixel is x, and a height of a non-active area between active areas of sub-pixels of a same color is y. In a display device with a reflecting layer, the height of an active area of a sub-pixel appears to increase to x′, and the height of a non-active area between active areas of sub-pixels of a same color appears to decrease to y′. For example, a height of the active area may appear to increase from 23 micrometers in a display device without a reflecting layer to a height of 30 micrometers in a display device with a reflecting layer. The height of the non-active area between active areas of sub-pixels of a same color may appear to decrease from 23 micrometers in a display device without a reflecting layer to 16 micrometers in a display device with a reflecting layer. This can result in an increase of approximately 30% in the vertical direction of the active area of the sub-pixel. Overall, the fill factor of the sub-pixel may increase approximately 20%.

FIG. 6Ais an example isometric view of a portion of a display device600with an optical reflecting layer624, according to one or more embodiments. The reflective layer624can be a same reflective layer as reflective layer124inFIGS. 1 and 2. A lower plane601shown inFIG. 6Adepicts active area610and non-active area620of sub-pixels in a lower structure of a display device. A portion of light650from the active area610of a sub-pixel from the lower plane601reflects off a portion624athe reflective layer624towards a viewing user. A portion of light640from the active area610of lower plane601may pass directly through openings in the reflective layer624.

FIG. 6Bis an example isometric view of a portion of a display device600with an optical reflecting layer624, according to one or more embodiments. InFIG. 6B, the portions630corresponding to non-active area in between sub-pixels of a different color can be more clearly seen. The portions630may correspond to portions330as shown inFIG. 3Awhich may correspond to a black matrix layer in between sub-pixels of different colors (e.g., between sub-pixels of a same pixel).

FIG. 6Cis an example side view of a portion of a display device600with an optical reflecting layer624. The side view shown inFIG. 6Cis a cross section that is taken across a region of the reflective layer624corresponding to active area610of the lower plane601. An active area610corresponds to a region not covered by the reflective layer624. The active area610also corresponds to a region not covered by portions630shown in the reflective layer624that may correspond to a black matrix layer between sub-pixels. A portion624aof the reflective layer624reflects light650from the active area610of the lower plane601to cover portions of a non-active area620. The light640from the active area610of the lower plane601directly passes through openings in the reflective layer624.

Additional Configuration Information