Patent Description:
Expanding a display to cover more area of a mobile device (e.g., mobile phone, tablet, etc.) may be desirable from, at least, a user experience standpoint. However, electro-optical devices positioned on a side of the mobile device that also includes the display (e.g., a front-facing camera, a light sensor, etc.) may compete for real estate on the side of the device that includes the display. In some implementations, electro-optical devices can be positioned behind a portion of the active (i.e., light emitting) display, so that display area need not be sacrificed to accommodate the electro-optical devices, and a device positioned behind a display may receive enough ambient light through the display for sensing an amount of ambient light. However, imaging through the display by a sensor located behind the display may be severely degraded by circuit elements of the display.

<CIT> discloses a display device including a display panel in which a part of the area is a transparent area and the remaining area is an opaque area and an electronic module arranged on the rear side of the transparent area in the display panel. Accordingly, the present invention can increase a ratio of a screen size to a device size.

<CIT> discloses a transparent organic light emitting display apparatus including a base substrate, a light blocking pattern disposed on the base substrate, a thin film transistor disposed on the base substrate, a first electrode disposed on the base substrate and electrically connected to the thin film transistor, a pixel defining layer disposed on the base substrate and overlapping the first light blocking pattern, a second electrode disposed on the base substrate, a light emitting structure disposed between the first electrode and the second electrode, and a second light blocking pattern overlapping the first light blocking pattern. The first light blocking pattern defines a first opening. The second light blocking pattern defines a second opening which overlaps the first opening. The pixel defining layer defines a third opening which overlaps the first and second openings configured to pass external light through the first to third openings.

<CIT> discloses a device comprising: a housing including a first surface facing a first direction and a second surface facing a second direction; a transparent cover formed on at least a portion of the first surface of the housing; a display disposed between the transparent cover and the second surface; a sensor disposed between the display and the second surface; and a control circuit, electrically connected to the sensor, for controlling the sensor. The display can comprise: a first region including a plurality of pixels capable of displaying color; and a second region aligned on at least a portion of the sensor such that light acquired from the outside of the electronic device passes through the sensor.

<CIT> discloses a display panel and a display device. The display panel comprises a first display region and a second display region. The second display region is adjacent to the first display region and is multiplexed to form a sensor reservation region. The second display region comprises a plurality of transmitting regions and a plurality of pixel unit arrangement regions. A first wiring region is arranged between two adjacent pixel unit arrangement regions along a first direction and a second wiring region is arranged between two adjacent pixel unit arrangement regions along a second direction. The first direction crosses with the second direction. The display panel also comprises a substrate and a shielding layer. The shielding layer is electrically connected with a preset voltage end. The positive projection of the shielding layer on the substrate completely covers positive projections of a gap, between two adjacent first wires, in the first wiring region and a gap, between two adjacent second wires, in the second wiring region on the substrate. Normal display of the sensor arrangement region is achieved, and the screen-to-body ratio of the display panel is improved.

<CIT> discloses a display device including: a first gate line and a second gate line which extend in a first direction; a signal line and a current-supplying line which extend in a second direction intersecting with the first direction; a first sub-pixel surrounded by the first gate line, the second gate line, the signal line, and the current-supplying line; and a light-shielding film located over the first sub-pixel. The light-shielding film has a first opening portion and a second opening portion, and the first sub-pixel overlaps with the first opening portion and the second opening portion and has an emission region and a light-transmitting region. In the light-transmitting region, a distance in the first direction between the signal line and the current-supplying line continuously changes along the second direction.

According to the claimed invention, a mobile computing device is defined as recited in claim <NUM>.

Implementations may include any of the following features, alone or in combination with each other.

For example, the first pattern of opaque portions may define transparent openings through which light passes through the AMOLED display to the camera, and where a lateral extent of the openings is greater than three times a wavelength of light that is imaged by the camera.

Opaque portions of the first pattern that define the transparent openings may be closer to a central axis passing through the openings, the central axis being parallel to a propagation direction of light that passes through the AMOLED display to the camera, than opaque portions of the second pattern.

The opaque portions of the first pattern and opaque patterns of the second pattern may be arranged such that light passing between the first and second opaque patterns at an angle of more than <NUM> degrees from the propagation direction of light that passes through the AMOLED display to the camera is blocked by the second opaque pattern from reaching the camera.

The second pattern of opaque portions may include TFT layers of the AMOLED display.

The first pattern of opaque portions may be located in the area of the transmit/receive region aligned with pixels of the display to allow light from the pixels to shine through openings in the first patterns and out of the AMOLED display.

The opaque portions of the first pattern may include touch sensor electrodes of the AMOLED display.

At least some of the touch sensor electrodes may be covered by material having an optical absorption of greater than <NUM>%.

The circuit elements in the transmit/receive region may include conductive lines configured to provide electrical signals to pixels in the AMOLED display.

A width of the conductive lines may be greater than one micron.

Two or more of the conductive lines may be parallel to each other, with a gap between the parallel conductive lines being less than five microns.

Two or more of the conductive lines may be parallel to each other, with a pitch of the parallel conductive lines in the transmit/receive area being smaller than a pitch of parallel conductive lines in other areas of the AMOLED display.

Opaque portions of the second light-blocking may include control lines that provide electrical power and/or electrical control signals to OLED emitters in the AMOLED display.

The device and/or the display may include control lines that provide electrical power and/or electrical control signals to OLED emitters in the AMOLED display, where opaque portions of the second light-blocking include control lines that located in a plane of the control lines.

A first light-blocking layer may have less area than the second light-blocking layer, where the second light-blocking layer blocks light diffracted by the first light-blocking layer and light diffracted by the control lines from reaching the camera.

According to another aspect of the claimed invention, an active matrix organic light emitting diode (AMOLED) display is defined as recited in claim <NUM>.

Opaque portions of the first pattern that define the transparent openings may be closer to a central axis passing through the openings, the central axis being parallel to a propagation direction of light that passes through the AMOLED display, than opaque portions of the second pattern.

Opaque portions of the first pattern and opaque patterns of the second pattern are arranged such that light passing between the first and second opaque patterns at an angle of more than <NUM> degrees from the propagation direction of light that passes through the AMOLED display to the camera is blocked by the second opaque pattern from passing through the AMOLED display.

Two or more of the conductive lines may be are parallel to each other, with a pitch of the parallel conductive lines in the transmit/receive area being smaller than a pitch of parallel conductive lines in other areas of the AMOLED display.

The display may further include control lines that provide electrical power and/or electrical control signals to OLED emitters in the AMOLED display, and where opaque portions of the second light-blocking include control lines are located in a plane of the control lines.

A first light-blocking layer may have less area than the second light-blocking layer, and the second light-blocking layer may block light diffracted by the first light-blocking layer and light diffracted by the control lines from reaching the camera.

The components in the drawings are not necessarily drawn to scale and may not be in scale relative to each other. Like reference numerals designate corresponding parts throughout the several views.

The present disclosure describes a flat panel display that can be used with a mobile device (e.g., mobile phone, tablet, etc.). The front surface of a mobile device includes a display typically operating as a graphic user interface (GUI) and one or more optical devices operating as sensors/emitters for areas outside the device and facing the front surface of the device. The one or more optical devices can be configured for a variety of functions, including, but not limited to, sensing lighting conditions (e.g. a light sensor), sensing proximity of objects to the device (e.g., a proximity sensor), capturing images (e.g., a front-facing camera), and/or to providing light (e.g., a flash). An optical device can be located under a portion of the display, such that display area need not be sacrificed to accommodate the optical device on the front surface of the mobile device. Circuitry and optical masks within the mobile device can be arranged, such diffraction of light passing through the display to the optical device is reduced compared to conventional configurations of mobile devices.

Traditionally, the display and the optical devices have occupied separate areas of the front surface of the mobile device. For example, <FIG> depicts a mobile device <NUM> having a display <NUM> and a camera <NUM> that occupy different portions of the front surface. Recent advances in emissive display technology (e.g., active matrix organic light emitting diode (AMOLED)) facilitate extending the emissive (i.e., active) area 110a of the display <NUM> towards (e.g., to) the edges of the mobile device <NUM>. By extending the active area of the display <NUM> towards the edges of the mobile device <NUM>, a user may experience the benefits of a larger display without the drawbacks of a larger device.

The disclosed emissive display is configured to share the front surface of a mobile device with one or more optical devices so that the active area of the display can be extended to the edges, without the need for leaving gaps in the display for the optical devices. Accordingly, one or more portions of the disclosed display covering the one or more optical devices can be configured so that the optical devices, positioned behind the display, can transmit or receive electromagnetic radiation (e.g., light) through the display.

<FIG> illustrates a mobile device <NUM> with a display <NUM> extended towards the edges of the device. Unlike mobile devices in which the display is excluded from an area reserved for optical devices, the light-emitting (i.e., active) area 112a of the display <NUM> extends over substantially the entire front surface. Accordingly, almost all of the, if not the entire, front surface of the mobile device <NUM> may be used to present color, black-and-white, or gray-scale images, graphics, and/or characters. The light-emitting area 112a of the display <NUM> includes a transmit/receive area <NUM> behind which (i.e., below which) an optical device (or optical devices) may be disposed and through which light can pass to be received by the optical device and/or through which light can be transmitted from the optical device out of the display <NUM>.

The size, shape, and/or position of the transmit/receive area <NUM> may be implemented variously. For example, the transmit/receive area <NUM> shown in <FIG> has a rounded (e.g., circular) shape and is positioned apart from edges of the display <NUM>. This need not be the case. In fact, advantages (e.g., signal routing, reduced fabrication complexity, etc.) may exist for different shapes and/or positions. For example, the transmit/receive area <NUM> shown in <FIG> is rectangular in shape and is positioned along an edge of the light-emitting area 113a of the display <NUM> of the mobile a mobile device <NUM>. In this implementation, the horizontal and vertical edges of the transmit/receive area <NUM> can correspond to the horizontal and vertical direction of electrically conductive signal lines and to a grid arrangement of light-emitting pixels in the display <NUM>. Additionally, the size of the transmit/receive region <NUM> in <FIG> can be larger than that of <FIG>.

<FIG> depicts a side, cross-sectional view of a mobile device having a display <NUM> with multiple transmit/receive regions 220A, 220B. The mobile device includes a multiple optical devices 240A, 240B, each positioned behind one of the transmit/receive regions. In some implementations, multiple (e.g. three) optical devices may be positioned behind a single transmit/receive region that is large enough to accommodate all the multiple devices. <FIG> depicts a side, cross-sectional view of a mobile device having a display <NUM> with a single transmit/receive region for use by the multiple optical devices 240A, 240B.

The optical devices 240A, 240B may transmit and/or receive electromagnetic radiation <NUM> through the transmit/receive regions 220A, 220B, 220C. While the disclosure may be generally applied to any optical device configured to transmit or receive electromagnetic radiation (e.g., from the millimeter wave, visible, or infrared portions of the electromagnetic spectrum), the particular implementation of a camera configured to receive visible light and/or infrared light will be considered throughout the disclosure.

The transmit/receive region 220A, 220B, 220C (i.e., portion) of the display <NUM> may have a different pixel density and/or pixel arrangement than the rest of the display. For example, the display region of the rest of display may have a pixel resolution that is higher than the pixel resolution of the transmit/receive portion 220A, 220B, 220C of the display.

<FIG> depicts LEDs <NUM> of pixels and electrically conductive signal lines <NUM> providing electrical signals to the LEDs <NUM> in a high-resolution portion of an emissive display, while <FIG> depicts a reduced-resolution portion of an emissive display that includes emissive areas <NUM> that include multiple light-emitting sub-pixels <NUM>, <NUM>, <NUM> and electrically conductive signal lines <NUM> providing electrical signals to pixel circuits that drive the sub-pixels. In <FIG> and in <FIG>, pixels in the display can include a plurality of light emitting elements (e.g., light emitting diodes) that emit different colors, so that all visible colors can be produced by a pixel by mixing amount of light from the different elements. For example, in some implementations, a pixel can include a red LED <NUM>, a blue LED <NUM> and two green LEDs <NUM>. The reduced-resolution portion of the display depicted in <FIG> may allow more light to pass through the display than the high-resolution portion of the display depicted in <FIG>, because there are fewer non-transparent elements, such as signal lines <NUM>, emissive areas <NUM>, and transistors placed in the reduced-resolution portion of the display than there are in the normal resolution portion of the display. Nevertheless, the light passing through the display may interact with some pixels and some signal lines <NUM> running in a vertical (y) direction or signal lines <NUM> running in a horizontal (x) direction, which can affect the propagation of light through the display.

<FIG>, not according to the claimed invention, illustrates a side, cross-sectional view of an emissive display <NUM> suitable for use with the mobile device of <FIG>. In some implementations the display <NUM> can be an AMOLED display. While the principles of the disclosure may be applied to various other display technologies, the implementation of an AMOLED display will be considered throughout the disclosure.

As shown in <FIG>, the AMOLED display <NUM> includes a plurality of layers. The layers are positioned behind (i.e., below) a cover glass layer <NUM> that can form the front surface of the mobile device <NUM>. In a possible implementation, the display <NUM> can include a polarization film layer <NUM>, which can improve a visual quality (e.g., contrast) of the light emitted from the display. The display <NUM> can also include a touch sensor layer <NUM> that includes touch sensor electrodes <NUM>. Individual pixels <NUM> of the display can be formed from a cathode layer <NUM>, an OLED emitter stack <NUM>, and separate elements of an anode layer <NUM>. Elements of the anode layer <NUM> may be reflective so that light emitted from the OLED emitter stack <NUM> toward the anode is reflected from the anode and directed in a vertical (z) direction from the anode layer <NUM>. An element of the anode layer <NUM> can be coupled to a thin film transistor (TFT) structure <NUM> that includes a source, a gate, and a drain, and which can be controlled by electrical signals transmitted over electrically conductive signal lines <NUM>. The display <NUM> can further include a barrier layer <NUM> of SiNx or SiONx and a substrate layer <NUM> of polyimide (PI).

The layers of the display <NUM> may include transparent and non-transparent circuit elements. For example, the TFT structure <NUM>, the pixels <NUM>, the signal lines <NUM>, and/or touch sensor electrodes <NUM> may all block light from propagating through the display <NUM>. Light can be either reflected or absorbed by the non-transparent (i.e., opaque) circuit elements. Additionally, the circuit elements may define gaps (i.e., slits) between circuit elements, with which the light may interact. For example, light may be diffracted by gaps formed between adjacent circuit elements in the same layer. The dimension of a gap relative to the wavelength of the light ray <NUM> can determine the effect the gap has on the light. A gap that is much wider than the wavelength of light passing through the gap may have little effect on the light as it passes through the gap. However, a gap having a width that is smaller than or comparable to (e.g., less than three times) the wavelength of light passing through the gap may have a more significant diffractive effect on the light passing through the gap. Light may also be diffracted by gaps between circuit elements in different layers, although the effect may be weaker than the diffraction due to elements of the same layer. For example, in some implementations, parallel signal lines <NUM> can be aligned next to each other with a center-to-center pitch of between <NUM> and <NUM> microns, with <NUM>-<NUM> microns wide gaps between adjacent signal lines. Similarly, gaps and slits defined by non-transparent elements in addition to the signal lines <NUM> (e.g., capacitors, TFT structures <NUM>, pixels <NUM>, the touch sensor electrodes <NUM>, etc.) also can diffract light as it propagates through the display to the camera.

<FIG>, not according to the claimed invention, depicts a side, cross-sectional view of a portion of a display <NUM> with light diffracted by circuit elements in the display. As shown, a light ray (i.e., light) 502A may pass between touch sensor electrodes 522A, 522B and between pixels 537A, 537B without being altered substantially, although some limited diffraction of light may occur at the edges of the touch sensor electrodes 522A, 522B and the pixels 537A, 537B. However, the light 502A can be diffracted by a gap (i.e., slit) formed between non-transparent elements (e.g., two adjacent electrically conductive signal lines 542A, 542B) when the dimensions of gaps between those non-transparent elements is less than or on the order of the wavelength of light. Accordingly, light may be diffracted by gaps formed by other combinations of circuit elements provided the gaps formed are of suitable dimensions. For example, light 502B can be diffracted by a gap formed between a signal line 542C and a TFT structure <NUM>.

When light is considered as a collection of rays, diffraction may be understood as effectively changing angles of some of the rays in the collection of rays so that the diffracted rays 520A, 520B are distributed over a diffraction angle. In general, narrower gaps in the display result in larger diffraction angles. Accordingly, higher resolution displays may cause more pronounced diffraction (i.e., larger diffraction angles) of light passing through the displays, because the density of the electrically conductive control lines in these displays is higher and the gaps between control lines in these displays are smaller.

A camera positioned behind (i.e., below) the display <NUM> relies on a lens to focus a light from an object onto a sensor (e.g., a CMOS, CCD array), with the sensor surface being located as the focal plane of the lens. However, when the light rays that pass through the display to the lens are diffracted by opaque elements in the display, many rays will not be focused onto the surface of the sensor but rather will have an effective focal plane above or below the sensor surface. As a result, an image captured from light that passes through a display can be distorted by diffraction.

<FIG> depicts a simulated image of an object (i.e., a 3D model head) captured without diffraction <NUM>, and <FIG> depicts a photograph of a head captured with diffraction through one of the existing display panels) <NUM>. As shown, the image formed with light including diffracted light is severely degraded and appears hazy because of the diffracted light rays. An aspect of the present disclosure is reducing diffraction caused by a display panel structure to improve the quality of images captured through the display (i.e., reduce a haze in the images).

The present disclosure describes a display having a transmit/receive region <NUM> that, when positioned over (i.e., in front of) a camera, facilitates imaging by decreasing the amount of light that causes image distortion from reaching the camera. This may be partially accomplished by reducing a number of pixels in the transmit/receive region (see <FIG>) (i.e., compared to other areas of the display) to allow more light to pass through the display. The pixels in the transmit/receive area may be regularly arranged (e.g., in a grid pattern) or may be non-regularly arranged. The number of pixels per unit area in the transmit/receive area may be smaller than that of the rest of display screen (e.g., the high-resolution area). In other words, a portion of pixels in the transmit/receive area can eliminated so that the remaining pixels are spaced further apart than the pixels of other parts of the display. This approach alone may still permit light to diffract from gaps formed between circuit elements (e.g., electrically conductive signal lines <NUM>, <NUM>). Accordingly, the present disclosure includes additional modifications of the transmit/receive region (as compared to other regions) to increase throughput and decrease diffraction.

An additional modification includes a routing of signal lines to the pixels in a transmit/receive area <NUM> of a display <NUM>, <NUM> in a manner designed to provide large areas without opaque elements though which light can propagate largely without diffraction. <FIG> depicts a possible arrangement of electrically conductive control lines of a transmit/receive area of a display. Each <NUM> by <NUM> clustered pixel <NUM> in this example pixel arrangement can include four sub-pixels in total, one red (e.g., upper left), two green (e.g., lower left and right), and one blue (e.g., upper right) sub-pixels, where the sub-pixels correspond to individual OLED emitters that can emit light of different colors. For example, a pixel of the display that can emit light of any color can include three or more sub-pixels that emit light of having at least three different colors, and the intensity of the different colors can be controlled, so that when mixed, the light from the multiple sub-pixels can produce light having any color. The sub-pixels are addressed with electrically conductive control lines <NUM> that carry signals to the pixels to control their illumination. In <FIG>, on the left is a reduced resolution portion of a display with signal lines that are not rearranged, while on the right is a reduced resolution portion of a display with signal lines that are rearranged (e.g., bundled together) to create openings <NUM>. The openings <NUM> provide substantially clear apertures through which light can pass to reach an optical device (or devices) positioned behind the display. In other words, the openings <NUM> are free of pixels or other circuit elements that could diffract light. The rearranged signal lines may still form gaps that can diffract light. In some implementations, to form the openings <NUM>, the signal lines can be arranged such that neighboring parallel signal lines are less than about five microns apart from each other, even when the pixel density in the reduced resolution portion of the display is less than about 165ppi (i.e., pixels are spaces about <NUM> microns from neighboring pixels). In some implementations, the pitch of (i.e., the center-to-center distance between) parallel control lines can be smaller in the low-resolution portion of the display than in other high-resolution portions of the display.

As mentioned, the circuit elements may form gaps (i.e., slits) that can diffract the light, and constraining the circuit elements (e.g., control signal lines) into bundled smaller regions (e.g., to create openings in the transmit/receive region) can enhance the diffraction. However, to reduce diffracted light from reaching the camera, light directed to circuit elements of the display that would cause deleterious diffraction can be blocked before reaching the circuit elements or after being diffracted by the circuit elements but before reaching the camera (i.e., after passing through the circuit elements). Accordingly, an aspect of the disclosed display includes a light-blocking layer that includes an opaque pattern aligned with the circuit elements in the transmit/receive area to block light before or after propagating through light-diffracting gaps formed by the circuit elements.

<FIG> is a top view of an opaque pattern <NUM> configured to block light from passing through gaps between opaque elements in the display, to avoid diffraction of light by the gaps. The opaque pattern <NUM> corresponds to a pattern of circuit elements (e.g., signal lines) of the portion of the display portion shown in <FIG> and is shaped and aligned accordingly. The opaque pattern may be made from a material (or materials) that is reflective or absorptive to wavelengths of the light captured by the camera. The opaque pattern may be any thickness (e.g., the thickness of a deposited metal trace) but thin layers can offer additional flexibility and may reduce the effect of unwanted shadows. In implementations in which the light-blocking layer is positioned above the pixels of the transmit/receive region, the opaque layer may include apertures <NUM> that are aligned with emissive areas in pixels (i.e., sub-pixels) in the transmit/receive region to allow light emitted from the pixels to transmit light through the apertures and out of the surface of the device.

<FIG> is a top view of another opaque pattern <NUM> configured to block light from passing through gaps between opaque elements in the display, to avoid diffraction of light by the gaps. The opaque pattern shown in <FIG> may include a single aperture <NUM> that allows all sub-pixels to transmit light through the aperture and out of the surface of the device. While this single aperture <NUM> can reduce part of the benefit of the opaque layer by leaving exposed some of the diffracting gaps that are located above or underneath this big single aperture <NUM>, alignment of the larger aperture <NUM> with the emissive sub-pixels may be easier than aligning the pattern of <FIG> with the emissive elements.

<FIG>, not according to the claimed invention, depicts a side, cross-sectional view of a reduced-resolution portion of an emissive display <NUM> including an opaque layer above rearranged signal lines according to a possible implementation of the disclosure. Compared with <FIG>, the implementation in <FIG> has fewer pixels, and the electrically conductive signals lines <NUM> are arranged to form openings <NUM> that do not include circuit elements, which light <NUM> from outside the display can pass through without interacting with (e.g., being diffracted by) circuit elements. The lateral dimensions of an opening <NUM> through which the light passes through can be greater than three times the longest wavelength of light that passes through the opening and that is imaged by a camera located below the display <NUM>. The circuit elements can include control signal lines <NUM> and/or the TFT structures <NUM>. The circuit elements are blocked (i.e., shaded) from receiving light <NUM> that passed through the touch sensor electrode or any opaque layer <NUM> above the circuit element layers <NUM>. In other words, the touch sensor layer can be used as the light-blocking layer. The pixel emission light <NUM> is unaffected by the opaque pattern formed by the light blocking layer <NUM>, because the light blocking layer patterns <NUM> are aligned with the emissive pixels, such that light from the pixels can be emitted from the display without inhibition from the touch sensor electrodes <NUM> across the target angular range viewed by a user in front of the display stack.

Elements formed in the touch sensor layer located in the transmit/receive area of the display may be electrically active or inactive. For example, the electrodes in the touch sensor layer <NUM> can include dummy sensor elements that do not contribute to sensing or active sensor lines used to detect a touch. Either the dummy sensor elements or the active sensor lines (or both) may be used to form an opaque pattern to block light from reaching the gaps created by the signal lines <NUM>. Thus, an aspect of the disclosed display includes utilizing the touch sensor layer as a light-blocking layer by forming the electrode <NUM> for touch sensing into an opaque pattern to block (e.g., absorb, reflect) light <NUM> (e.g., visible and infrared light) that could otherwise be diffracted and degrade an image captured by a sensor located below the display panel. The display implementation of <FIG> may advantageously have fewer layers because the touch sensor layer serves a dual purpose.

<FIG>, not according to the claimed invention, depicts another side, cross-sectional view of the reduced-resolution portion of an emissive display. The touch sensor electrodes <NUM> are part of the touch sensor layer <NUM>, and the touch sensor electrodes <NUM> can include an opaque metal material (e.g., Al, Ti, Mo, Cu, Cr, Ag, Au, etc. or alloys thereof). In some implementations, the thickness of the touch sensor electrodes <NUM> can be about <NUM> - <NUM>.

Because the touch sensor electrodes <NUM> include metal material, the reflectivity of the metal material may be relatively high. To reduce the reflectivity of the touch sensor electrodes <NUM>, the electrodes may be covered with a layer of low reflectivity material. For example, in some implementations, the metal touch sensor electrodes <NUM> can be covered by an additional optically absorbing material <NUM> that covers the surface of touch sensor electrodes <NUM>. In some embodiments, the optically absorbing material <NUM> can extend around the edges of the electrodes to cover the edges of the metal touch sensor electrodes <NUM>. For example, the optically absorbing material <NUM> can include a black photoresist material, which can be similar in composition to materials used for LCD color filter fabrication and which is typically modified for low temperature curing necessary for compatibility with OLEDs (e.g. <NUM>-<NUM>). These materials have high optical absorption (e.g. > <NUM>% for a <NUM> thickness layer of photoresist) and can help decrease the amount of light scattered by metal touch sensor electrodes <NUM> towards the imaging device behind the display panel. In some implementations, the total combined thickness of the touch sensor electrodes <NUM> covered by an optically absorbing material <NUM> can be about <NUM> - <NUM>.

<FIG> depict side, cross-sectional views of a metal touch sensor electrode <NUM> in various stages of being covered by an opaque, low-reflectivity material. <FIG> depicts a side cross-sectional view of a metal touch sensitive electrode layer <NUM> on a supporting substrate layer <NUM>. <FIG> depicts a side cross-sectional view of a metal touch sensitive electrode layer <NUM> on a supporting substrate layer <NUM>, with a photoresist layer <NUM> above the metal layer <NUM>. The photoresist layer <NUM> can be patterned with conventional photolithography techniques (e.g., coating the underlying metal layer <NUM> with a photoresist layer spanning the substrate layer <NUM>, exposing the photoresist layer to a pattern of light, developing the exposed photoresist layer, baking the layer) to create the pattern of photoresist depicted in <FIG>. The photoresist layer typically can be about <NUM> - <NUM> thick. A metal etching process can be applied to the stack shown in <FIG> to remove material from the metal layer <NUM> that is not under the patterned photoresist layer <NUM>. <FIG> depicts a side cross-sectional view of the metal touch sensitive electrode layer <NUM> on the supporting substrate layer <NUM>, with a photoresist layer <NUM> above the metal layer <NUM>, after metal etching has been applied to remove metal from layer <NUM>, except under patterned resist <NUM>. The metal layer can be overetched, so that the photoresist layer <NUM> edges extend beyond the edges of the remaining metal electrode layer <NUM>. In some implementations, the structure shown in <FIG> can be further processed, so that the photoresist layer <NUM>, covers the edges of the metal layer <NUM>. For example, the structure shown in <FIG> can be heated, so that the photoresist <NUM> flows down over the edges of the metal layer <NUM> to form the structure shown in <FIG>.

A touch sensor layer for an emissive display may itself include multiple layers. <FIG> depicts a top view of electrodes in the touch sensor layer <NUM>. The electrodes include a transmit (TX) sensor electrode <NUM> and a receive (RX) sensor electrode <NUM>. <FIG> depicts a side, cross-sectional view of a portion (shown as A-A') of the touch sensor layers of <FIG>. As shown, the TX sensor electrode <NUM> and the RX sensor electrode <NUM> are coplanar and formed in a first metal layer <NUM>. The TX and RX electrodes form intercepting patterns. Accordingly, a second metal layer <NUM> can be used for a jumper (i.e., bridge) electrode <NUM> to allow the crossing-over electrical connections. The touch sensor layer <NUM> may further include a sensor passivation layer <NUM> and/or a sensor buffer layer <NUM>. The opaque pattern of the touch sensor electrode for blocking light may include either, or both, the first metal layer <NUM> and the second metal layer <NUM> of the touch sensor layer <NUM>. In this regard, the electrodes <NUM> shown in <FIG> may be generally regarded as being a part of a first metal layer <NUM> or as on a second metal layer <NUM> of the touch sensor layer <NUM>.

In some possible implementations, light diffracted within the display may be blocked from reaching the camera under the display after interacting with circuit elements in the display. <FIG>, not according to the claimed invention, depicts a side, cross-sectional view of an emissive display including an opaque layer below signal lines according to a possible implementation of the disclosure. The display can include an opaque pattern <NUM>, which is located between the substrate (e.g., polyimide layer) <NUM> and the bottom most semiconducting layer <NUM> for blocking light. The opaque pattern <NUM> on the substrate <NUM> can include one or multiple layers comprising, for example, metal, photoresist, polymer, and other materials forming an opaque structure. The opaque pattern <NUM> is positioned below and aligned with the circuit elements (e.g., signal lines) that can cause deleterious diffraction of light <NUM> passing through gaps between the elements, resulting in diffracted light <NUM>. The diffracted light <NUM> can be blocked by the opaque pattern <NUM>. In the preferred embodiment pattern <NUM> is coated by a barrier layer <NUM> that ensures a stable surface for forming the transistor elements <NUM>.

With the opaque pattern <NUM> of the light blocking layer being below the OLEDs of the pixels, apertures in the opaque layer for transmitted light <NUM> from pixels to shine through are unnecessary. Accordingly, the precision of alignment of the opaque mask with respect to the OLEDs may be relaxed somewhat compared to implementations requiring apertures for the OLEDs. As shown in <FIG>, the spacing between the opaque pattern <NUM> and the circuit elements (e.g., signal lines) is made small enough that diffracted light <NUM> is blocked before it can reach an opening <NUM>.

The present claimed invention addresses the fact that plane waves of light do not pass through even large openings (i.e., openings that are significantly larger than the wavelength of light) completely without diffraction, but rather suffer some diffraction by the edges of the openings, which can lead to distortion of light as it passes through a display to reach a camera under the display.

<FIG>, according to the claimed invention, depicts a side, cross-sectional view of an emissive display <NUM> including a first light-blocking layer that includes a pattern of opaque portions <NUM> above electrically conductive signal lines <NUM> and also including a second light-blocking (e.g., collimation or mask), layer that includes a second pattern of opaque portions <NUM> that further reduces light diffracted by elements in the display <NUM> from reaching a camera under the display <NUM>.

The emissive display <NUM> can include a cover glass layer <NUM>, a polarization layer <NUM>, and a touch-sensitive layer <NUM>. The display <NUM> can include light emitting diode (LED) pixel structures <NUM> and thin film transistors (TFT) <NUM> that supply electrical power to the LED structures to drive the structures to emit light out of the top surface of the display. The electrical power can be supplied to the LED structures between a cathode <NUM> and an anode <NUM>. Opaque control lines <NUM> that include, for example, metal material can supply electrical signals and electrical power to the TFTs <NUM> that drive the OLED emitter structure <NUM>. The components of the display <NUM> can be fabricated on a substrate <NUM>, which can include, for example, a polyimide (PI) material or glass. The display can further include a barrier layer <NUM> of, for example, SiNx or SiONx, between the substrate <NUM> and other components in material stack of the display <NUM>.

The touch sensor layer <NUM> can include touch sensor electrodes <NUM>, as described above, that may be opaque to light received by the display <NUM>. Signal lines <NUM> can be located under and touch sensor electrodes <NUM> and within the lateral extent of the touch sensor electrodes <NUM>, so that light passing through the display <NUM> is blocked by the opaque electrodes <NUM> from reaching the signal lines <NUM>, so that the light is not diffracted by the signal lines <NUM>.

Light <NUM> that passes through the display to a camera located below the display <NUM> passes through relatively large openings <NUM> that are free of non-transparent elements, such that the light <NUM> can pass through the display <NUM> without interacting with (e.g., being diffracted by) circuit elements. An opening <NUM> is defined by an aperture of the light blocking layer, for example an aperture defined by the sensor electrodes <NUM> in the touch layer <NUM> of the display <NUM> in <FIG>. In some implementations, the smallest lateral dimension of an opening <NUM> can be greater than three times the longest wavelength of light that passes through the opening <NUM> and that is imaged by a camera located below the display <NUM>.

In some implementations, all of the light that is imaged by the camera below the display <NUM> can pass through relatively large openings <NUM> that are free of non-transparent elements and whose smallest lateral dimension is greater than three times the longest wavelength of light that is imaged by the camera. In some implementations, at least <NUM>% of the light that is imaged by the camera below the display <NUM> can pass through relatively large openings <NUM> that are free of non-transparent elements and whose smallest lateral dimension is greater than three times the longest wavelength of light that is imaged by the camera. In some implementations, at least <NUM>% of the light that is imaged by the camera below the display <NUM> can pass through relatively large openings <NUM> that are free of non-transparent elements and whose smallest lateral dimension is greater than three times the longest wavelength of light that is imaged by the camera. In some implementations, at least <NUM>% of the light that is imaged by the camera below the display <NUM> can pass through relatively large openings <NUM> that are free of non-transparent elements and whose smallest lateral dimension is greater than three times the longest wavelength of light that is imaged by the camera.

As explained above, light that passes through a relatively large opening is substantially undisturbed by the opening. However, structures at the boundaries or edges of the opening still can diffract the light. As shown in <FIG>, a plane wave <NUM> passing through opening <NUM> can be diffracted somewhat by the edges of the sensor electrodes <NUM> that form the boundaries of the opening <NUM>. Thus, a portion of the light <NUM> that passes close by the edges of the sensor electrodes <NUM> that form the boundaries of the opening <NUM> can be distorted from its plane wave pattern, such that, in a ray-tracing representation of the light, a portion <NUM> of the light is diverted outward, away from a central axis of the opening <NUM>. The imaging of such light by the camera under the display <NUM> would lead of haze and/or distortion in an image created by the camera.

To address this issue, the structures of the opaque collimation or mask layer <NUM> are positioned below the opaque diffracting sensor electrodes <NUM>, such that they block a portion of the diverted light <NUM> from passing through the display <NUM> and reaching the camera. Relative to the central axis of the opening <NUM>, which is parallel to the propagation direction of the light <NUM>, the inside edge (i.e., closest edge to the central axis) of a mask layer structure <NUM> is located below, and slightly outboard (away from the central axis), of a line parallel to an inside edge of the sensor electrode <NUM> that diffracts the light.

An angle, α, between a line parallel to the propagation direction of the light that grazes the edge of an electrode <NUM> and a line from the edge of the electrode <NUM> to the edge of the collimation layer structure <NUM> can be selected to minimize the amount of light diffracted by the edge of the electrode <NUM> that reaches the camera under the display <NUM>. When the angle, α, is zero, then light from the plane wave <NUM> is diffracted not only by the edge of the electrode <NUM> but also by the edge of the collimation layer structure <NUM>, such that the collimation layer structure <NUM> may cause additional deleterious diffracted light that reaches the camera, resulting in additional haze in images formed by the camera. On the other hand, when the angle, α, is too high, then light from the plane wave <NUM> that is diffracted by the edge of the electrode <NUM> may not be blocked by the collimation layer structure <NUM> from reaching the camera. Thus, an optimal angle can be between about six degrees and about ten degrees.

The collimation structures <NUM> can include metal material or other opaque material fabricated in the stack of material of the display. For example, the collimation structures <NUM> can be formed during the fabrication of pixel circuit layers. To reduce diffraction from edges of the collimation structures <NUM>, the vertical thickness of the structures can be relatively thin, for example, less than approximately two micrometers, so that the collimator structure <NUM> approximates a knife edge barrier to the light <NUM>, <NUM>.

Variations to the implementations described may exist. For example, the structures above the LEDs that block light from reaching the control lines <NUM> need not be touch sensor electrodes <NUM> but may be, or may include, other opaque structures that either have a dedicated purpose in the display <NUM> of providing a light blocking structure to reduce an amount of diffracted light from reaching the camera under the display <NUM> or that perform this function in addition to performing one or more other functions in the display.

In another example, the collimator structures <NUM> need not be stand-alone structures but, in some implementations, can be integrated with other structures of the display. For example, the collimator structures <NUM> can be part of a TFT structure <NUM>, and metal or other opaque materials of the TFT can function as the collimator structure that blocks diffracted light from the upper light blocking layer. In another example, the collimator structures <NUM> can be part of an anode <NUM>, and metal or other opaque materials of the anode can function as the collimator structure that blocks diffracted light from the upper light blocking layer.

<FIG>, according to the claimed invention, depicts side, cross-sectional view of another emissive display <NUM> including an opaque layer <NUM> above electrically conductive signal lines <NUM> and also including an opaque collimation or mask layer <NUM> that further reduces light diffracted by elements in the display <NUM> from reaching a camera under the display <NUM>. The emissive display <NUM> of <FIG> is similar to the emissive display <NUM> of <FIG>, except that, instead of the collimation layer being located in the plane of the anode <NUM>, the collimation layer <NUM> is located in the plane of the control lines <NUM>. For example, in one implementation, a metallic source/drain control line can function as the collimation layer <NUM> structure to block diffracted light from reaching the camera. In another implementation, the collimation layer <NUM> in the plane of the control lines need not function as a control line to supply electrical power or control signals to an OLED emitter stack but may be unconnected electrically to any OLED.

<FIG> is a top view of an example pattern <NUM> of a light blocking layer (e.g., the light blocking layer structures <NUM> as shown in <FIG>) that serves to block diffracted light from reaching the camera below the display. The pattern <NUM> of the light blocking layer structures includes structures <NUM> that frame the portions of the emissive display that correspond to OLED emitter stacks and control lines that provide electrical power and control signals to the OLED emitter stacks. The opaque lines <NUM> of the pattern can block light diffracted from structures higher in the stack from reaching the camera under the display.

<FIG>, according to the claimed invention, depicts a side, cross-sectional view of another emissive display <NUM> including an opaque light blocking layer <NUM> above electrically conductive signal lines <NUM> and also including a collimation or mask layer <NUM> below the signal lines that prevents light diffracted by elements in the display from reaching a camera under the display <NUM>. The upper light blocking layer <NUM> can shadow the signal lines <NUM> and other diffractive structures in the display, so that the signal lines <NUM> and other diffractive structures do not diffract light that then reaches the camera. The collimation or mask layer <NUM> can be positioned such that it intercepts light that is diffracted by structures (e.g., edges of the upper light blocking layer <NUM>) in the display prevents at least a portion of the diffracted light from passing through the display and reaching the camera. As with <FIG>, the aperture <NUM> formed by the upper light blocking layer <NUM> can be smaller than the aperture formed by the lower light blocking layer <NUM>. The collimation or mask layer <NUM> can be integrated into the substrate layer <NUM> or can be patterned on top of the substrate layer <NUM>. In some implementations, the lower light blocking layer <NUM> can be in located in the plane of layer that includes TFTs, and the light blocking layer <NUM> can be formed in a processing step in which the TFT layer is formed. In some implementations, the light blocking layer <NUM> can include semitransparent semiconductor material, e.g. amorphous or polycrystalline silicon layer, which attenuates the diffracted light <NUM>.

<FIG>, according to the claimed invention, depicts a side, cross-sectional view of another emissive display <NUM> including an opaque layer light blocking <NUM> above electrically conductive signal lines <NUM> and also including a mask layer <NUM> below the signal lines <NUM> that prevents light diffracted by elements in the display from reaching a camera under the display <NUM>. In some implementations, the upper light blocking layer <NUM> can include a touch sensor electrode. The upper light blocking layer <NUM> can at least partially shadow the signal lines <NUM> and other diffractive structures in the display, but, when the dimensions of the upper light blocking layer <NUM> are relatively small it may not provide sufficient shadowing to prevent light from reaching the signal lines <NUM> and other diffractive elements. However, the lower mask layer <NUM> can have dimensions, and be positioned, such that it intercepts light that is diffracted by the signal lines <NUM> and other diffractive structures in the display and prevents the light from reaching the camera. Because the edges of the lower mask layer <NUM> still cause some diffraction of light, which then reaches the camera, an intensity of light reaching the edges of the lower mask layer <NUM> can be reduced the opaque angular filtering elements <NUM> positioned above the lower mask layer <NUM>, such that they shadow the edges of the lower mask layer <NUM> and light diffracted by the edges of the angular filtering elements is at least partially intercepted by the lower mask layer <NUM>. In this manner, although edges of the angular filtering elements <NUM> diffract light, some of that diffracted light is blocked from reaching the camera by the lower mask layer <NUM>, and a lower intensity of light is diffracted by the lower mask layer <NUM>. Thus, the angular filtering elements <NUM> in conjunction with the lower mask layer <NUM> can lower the total amount of diffracted light that reaches the camera, compared to a version of the display in <FIG> that does not include the angular filtering elements <NUM>.

In other implementations, layers may be added to the display with the sole purpose of blocking light. Further, layers other than the layers described thus far may be adapted to serve a dual purpose that includes blocking light. A light-blocking layer need not be integrated (e.g., laminated) with the display (i.e., as described thus far) as long as the function of blocking diffracted light from reaching a light sensor (e.g., camera) is accomplished.

The disclosed displays have been presented in the context of a mobile device, such as a tablet or a smart phone. The principles and techniques disclosed, however, may be applied more generally to any display in which it is desirable to position a sensor behind the display. For example, a virtual agent home terminal, a television, or an automatic teller machine (ATM) are a non-limiting set of alternative applications that could utilize a camera positioned behind an active area of a display. Further, the motivation for placing a camera behind a display is not limited to an expansion of the display to the edges of a device. For example, it may be desirable to place the camera behind a display for aesthetic or stealth reasons.

In the specification and/or figures, typical embodiments have been disclosed. The present disclosure is not limited to such exemplary embodiments. The use of the term "and/or" includes any and all combinations of one or more of the associated listed items. Unless otherwise noted, specific terms have been used in a generic and descriptive sense and not for purposes of limitation. As used in this specification, spatial relative terms (e.g., in front of, behind, above, below, and so forth) are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, a "front surface" of a mobile computing device may be a surface facing a user, in which case the phrase "in front of' implies closer to the user. Additionally, a "top surface" of a display may be the surface facing a user, in which case the phrase "below" implies deeper into an interior of the mobile computing device.

Claim 1:
A mobile computing device comprising:
an active matrix organic light emitting diode (AMOLED) display (<NUM>, <NUM>, <NUM>, <NUM>); and
a camera having a sensor located beneath the AMOLED display, such that light received by the sensor passes through a transmit/receive region of a light-emitting area of the AMOLED display, wherein the transmit/receive region has a pixel density that is lower than other regions of the light-emitting area and that includes circuit elements arranged such that they diffract visible light that passes through the transmit/receive region,
wherein the AMOLED display includes:
a first light-blocking layer (<NUM>, <NUM>, <NUM>, <NUM>) that includes a first pattern of opaque portions that are positioned above, and aligned with, the circuit elements to prevent light transmitted into the transmit/receive region from reaching the circuit elements; and
a second light-blocking layer (<NUM>, <NUM>, <NUM>, <NUM>) between the first light blocking layer and the camera and that includes a second pattern of opaque portions that is aligned with the first pattern, such that at least a portion of light transmitted into the transmit/receive region and diffracted by the first pattern of opaque portions is blocked by the second pattern of opaque portions from reaching the sensor of the camera,
wherein an aperture of the first light-blocking layer defines an opening (<NUM>, <NUM>, <NUM>, <NUM>) having a central axis which is parallel to a propagation direction of the light, and wherein an inside edge, being the closest edge to the central axis, of the second light-blocking layer is located below the first light-blocking layer and farther away from the central axis than a line parallel to the central axis and extending from an inside edge of the first light-blocking layer that defines the opening.