Organic light-emitting diode display with patterned anode and optical cavity

Abstract

The present disclosure relates to an organic light emitting diode display with a patterned anode and an optical cavity. A pixel in an organic light emitting diode (OLED) display may be a microcavity OLED pixel with an optical cavity. The optical cavity may be defined by a partially transparent cathode layer and a reflective anode structure. The anode of the pixel may include both the reflective anode structure and a supplementary anode, which is transparent and used to adjust the thickness of the optical cavity of each pixel. An organic light emitting diode layer may be formed on the pixel and may have a uniform thickness in each pixel in the display. The pixel may have a conductive spacer between the transparent anode portion and the reflective anode portion without an intermediate dielectric layer. The conductive spacer may be formed of a material compatible with the two anode portions, such as titanium nitride. The transparent anode portion may have a variable thickness to control the thickness of the optical cavity of the pixel.

Description

[0001] This patent application claims priority to U.S. Non-Provisional Patent Application No. 16 / 888,451 filed on May 29, 2020 and U.S. Provisional Patent Application No. 62 / 891,142 filed on August 23, 2019, which are hereby incorporated by reference in their entirety. Background Art

[0002] The present disclosure relates generally to electronic devices, and more particularly to electronic devices having displays.

[0003] Electronic devices often include displays. For example, an electronic device may have an organic light emitting diode (OLED) display based on organic light emitting diode pixels. In this type of display, each pixel includes a light emitting diode and a thin film transistor that is used to control the application of a signal to the light emitting diode to produce light. The light emitting diode may include an OLED layer positioned between an anode and a cathode. In order to emit light from a given pixel in an organic light emitting diode display, a voltage may be applied to the anode of the given pixel.

[0004] Some OLED pixels may include microcavity OLED pixels, in which the OLED layer is covered by a partially transparent layer to form an optical cavity. The thickness of the optical cavity can be adjusted so that light of a selected wavelength is emitted with high efficiency. However, if care is not taken, this type of OLED pixel may have an uneven thickness, may have an aperture ratio that is smaller than the desired aperture ratio, and / or may require a complex manufacturing process.

[0005] It is in this context that the embodiments of this article are generated. Summary of the invention

[0006] The present disclosure discloses an electronic device that may have a display such as an organic light emitting diode display. An organic light emitting diode (OLED) display may have an array of organic light emitting diode pixels, each of which has an OLED layer interposed between a cathode and an anode.

[0007] The pixels in the OLED display can be microcavity OLED pixels with an optical cavity. The optical cavity can be defined by a partially transparent cathode layer and a reflective anode structure. The anode of the pixel can include a supplementary anode that is transparent and used to adjust the thickness of the optical cavity of each pixel.

[0008] A white organic light emitting diode layer may be formed over the pixels and may have a uniform thickness in each pixel in the display. The thickness of the transparent anode stack including the supplementary anode and the additional spacer layer is used to control the thickness of the optical cavity of each pixel. Blue pixels, green pixels, and red pixels may have optical cavities that gradually thicken.

[0009] The blue pixel may have a conductive spacer between the transparent anode portion and the reflective anode portion. The conductive spacer may be formed of a material compatible with the two anode portions, such as titanium nitride. No other dielectric layer may be formed between the anode portions of the blue pixel. This means that the blue pixel does not require a via, thereby increasing the aperture ratio of the blue pixel.

[0010] In some arrangements, the transparent anode portion may have a varying thickness to control the thickness of the optical cavity of the pixel. For example, the transparent anode portion of a red pixel may be thicker than the transparent anode portion of a green or blue pixel. In such an arrangement, the dielectric layer under the transparent anode portion of the red pixel may be thinner, making it easier to form a via through the dielectric layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram of an illustrative electronic device with a display according to one embodiment.

[0012] Figure 2 is a schematic diagram of an illustrative display according to one embodiment.

[0013] Figure 3 is a diagram of an illustrative display pixel circuit according to one implementation.

[0014] Figure 4 is a cross-sectional side view of an illustrative display having a microcavity organic light emitting diode pixel including at least one pixel without a through hole between anode portions according to an embodiment.

[0015] Figure 5 is a cross-sectional side view of an illustrative display having a microcavity organic light emitting diode pixel with various anode portions having different thicknesses according to one embodiment.

[0016] Figure 6 is a cross-sectional side view of an illustrative display having a microcavity organic light emitting diode pixel including three color pixels without a through hole between anode portions according to one embodiment. DETAILED DESCRIPTION

[0017] Figure 11 shows an exemplary electronic device of the type that may have a display. Electronic device 10 may be a computing device such as a laptop computer, a computer monitor including an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device (such as a wristwatch device, a hanging device, a headset or earpiece device, a device embedded in glasses or other devices worn on a user's head, or other wearable or miniature devices), a display, a computer display including an embedded computer, a computer display not including an embedded computer, a gaming device, a navigation device, an embedded system (such as a system in which an electronic device with a display is installed in an information kiosk or a car), or other electronic device. Electronic device 10 may have the shape of a pair of glasses (e.g., a support frame), may be formed into a housing having a helmet shape, or may have other configurations for helping to mount and secure components of one or more displays on a user's head or near the eyes.

[0018] like Figure 1 As shown, electronic device 10 may include control circuitry 16 for supporting the operation of device 10. Control circuitry 16 may include memory, such as hard drive memory, non-volatile memory (e.g., flash memory or other electrically programmable read-only memory configured to form a solid-state drive), volatile memory (e.g., static random access memory or dynamic random access memory), etc. Processing circuitry in control circuitry 16 may be used to control the operation of device 10. The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application specific integrated circuits, etc.

[0019] Input-output circuitry in device 10, such as input-output devices 12, may be used to allow data to be provided to device 10, and to allow data to be provided from device 10 to external devices. Input-output devices 12 may include buttons, joysticks, scroll wheels, touch pads, keypads, keyboards, microphones, speakers, audio generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, data ports, etc. A user may control the operation of device 10 by supplying commands through the input resources of input-output devices 12, and may receive status information and other output from device 10 using the output resources of input-output devices 12.

[0020] The input-output device 12 may include one or more displays, such as a display 14. The display 14 may be a touch screen display including a touch sensor for collecting touch input from a user, or the display 14 may be insensitive to touch. The touch sensor of the display 14 may be based on an array of capacitive touch sensor electrodes, an acoustic touch sensor structure, a resistive touch component, a force-based touch sensor structure, a light-based touch sensor, or other suitable touch sensor arrangements. The touch sensor for the display 14 may be formed by electrodes formed on a common display substrate with display pixels of the display 14, or may be formed by an independent touch sensor panel overlapping the pixels of the display 14. If desired, the display 14 may be insensitive to touch (i.e., the touch sensor may be omitted). The display 14 in the electronic device 10 may be a head-up display that can be viewed without requiring the user to move away from a typical viewpoint, or may be a head-mounted display incorporated into a device worn on the user's head. If desired, the display 14 may also be a holographic display for displaying a hologram.

[0021] Control circuitry 16 may be used to run software, such as operating system code and application programs, on device 10. During operation of device 10, software running on control circuitry 16 may display images on display 14.

[0022] Figure 2 is a diagram of an exemplary display 14. Figure 2 As shown, display 14 may include layers such as substrate layer 26. Substrate layers such as layer 26 may be formed from rectangular planar material layers or material layers having other shapes (e.g., circular or other shapes having one or more curved edges and / or straight edges). Substrate layers of display 14 may include glass layers, polymer layers, silicon layers, composite films including polymer materials and inorganic materials, metal foils, and the like.

[0023] Display 14 may have an array of pixels 22, such as pixel array 28, for displaying images for a user. Pixels 22 in array 28 may be arranged in rows and columns. The edges of array 28 may be straight or curved (i.e., each row of pixels 22 and / or each column of pixels 22 in array 28 may have the same length or may have different lengths). There may be any suitable number of rows and columns in array 28 (e.g., ten or more, one hundred or more, or one thousand or more, etc.). Display 14 may include pixels 22 of different colors. For example, display 14 may include red pixels, green pixels, and blue pixels. Pixels of other colors, such as cyan, magenta, and yellow, may also be used.

[0024] Display driver circuitry 20 may be used to control the operation of pixels 28. Display driver circuitry 20 may be formed from integrated circuits, thin film transistor circuits, and / or other suitable circuits. Figure 2 Exemplary display driver circuit 20 includes display driver circuit 20A, and additional display driver circuits such as gate driver circuit 20B. Gate driver circuit 20B may be formed along one or more edges of display 14. For example, gate driver circuit 20B may be arranged along the left and right sides of display 14, such as Figure 2 shown.

[0025] like Figure 2 As shown, display driver circuit 20A (e.g., one or more display driver integrated circuits, thin film transistor circuits, etc.) may include communication circuitry for communicating with system control circuitry via signal path 24. Path 24 may be formed by traces on a flexible printed circuit or other wiring. The control circuitry may be located on one or more printed circuits in electronic device 10. During operation, the control circuitry (e.g., Figure 1 Control circuitry 16 ) may provide image data to circuitry such as a display driver integrated circuit in circuitry 20 for causing an image to be displayed on display 14 . Figure 2 Display driver circuitry 20A is positioned at the top of display 14. This is merely illustrative. Display driver circuitry 20A may be positioned at both the top and bottom of display 14, or in other portions of device 10.

[0026] To display an image on pixel 22, display driver circuit 20A may supply corresponding image data to data line D while issuing control signals to supporting display driver circuits such as gate driver circuit 20B via signal path 30. Figure 2 In the exemplary arrangement of FIG. 1 , data lines D extend vertically through display 14 and are associated with corresponding columns of pixels 22 .

[0027] The gate driver circuit 20B (sometimes referred to as a gate line driver circuit or a horizontal control signal circuit) may be implemented using one or more integrated circuits and / or may be implemented using thin film transistor circuits on the substrate 26. Horizontal control lines G (sometimes referred to as gate lines, scan lines, emission control lines, etc.) extend horizontally across the display 14. Each gate line G is associated with a corresponding row of pixels 22. If desired, there may be multiple horizontal control lines such as a gate line G associated with each row of pixels. Individually controlled signal paths and / or global signal paths in the display 14 may also be used to distribute other signals (e.g., power signals, etc.).

[0028] Gate driver circuit 20B may assert control signals on gate lines G in display 14. For example, gate driver circuit 20B may receive clock signals and other control signals from circuit 20A on path 30, and may sequentially assert gate line signals on gate lines G starting with gate line signal G in a first row of pixels 22 in array 28 in response to the received signals. As each gate line is asserted, data from data line D may be loaded into the corresponding row of pixels. In this manner, control circuits such as display driver circuits 20A and 20B may provide pixels 22 with signals for instructing pixels 22 to display a desired image on display 14. Each pixel 22 may have a light emitting diode and circuitry (e.g., thin film circuitry on substrate 26) that responds to control signals and data signals from display driver circuit 20.

[0029] The gate driver circuit 20B may include gate driver circuit blocks, such as gate driver row blocks. Each gate driver row block may include circuits such as output buffers and other output driver circuits, register circuits (e.g., registers that may be linked together to form a shift register), and signal lines, power lines, and other interconnects. Each gate driver row block may provide one or more gate signals to one or more corresponding gate lines in a corresponding pixel row of a pixel array in an active area of ​​the display 14.

[0030] A schematic diagram of an exemplary pixel circuit of the type that may be used for each pixel 22 in array 28 is shown in Figure 3 As shown in Figure 3 As shown, display pixel 22 may include light emitting diode 38. A positive power supply voltage ELVDD may be provided to positive power supply terminal 34, and a ground power supply voltage ELVSS may be provided to ground power supply terminal 36. Diode 38 has an anode (terminal AN) and a cathode (terminal CD). The state of drive transistor 32 controls the amount of current flowing through diode 38, and thus controls the amount of emitted light 40 from display pixel 22. Since cathode CD of diode 38 is coupled to ground terminal 36, cathode terminal CD of diode 38 may sometimes be referred to as a ground terminal of diode 38.

[0031] To ensure that transistor 38 remains in a desired state between consecutive data frames, display pixel 22 may include a storage capacitor, such as storage capacitor Cst. The voltage on storage capacitor Cst is applied to the gate of transistor 32 at node A to control transistor 32. One or more switching transistors such as switching transistor 33 may be used to load data into storage capacitor Cst. When switching transistor 33 is turned off, data line D is isolated from storage capacitor Cst, and the gate voltage at terminal A is equal to the data value stored in storage capacitor Cst (i.e., the data value from the previous frame of display data displayed on display 14). When gate line G (sometimes referred to as a scan line) in the row associated with display pixel 22 is asserted, switching transistor 33 will be turned on and a new data signal on data line D will be loaded into storage capacitor Cst. The new signal on capacitor Cst is applied to the gate of transistor 32 at node A, thereby adjusting the state of transistor 32 and adjusting the corresponding amount of light 40 emitted by light emitting diode 38. If desired, a light emitting diode (e.g., such as a light emitting diode) used to control a display pixel in display 14 may be turned on. Figure 3 The circuitry for the operation of the display pixel circuit ... Figure 3 The display pixel circuits shown are merely illustrative.

[0032] Figure 4 is a cross-sectional side view of an illustrative display having an organic light emitting diode display pixel. As shown, display 14 may include substrate 26. Substrate 26 may be formed of glass, plastic, polymer, silicon, or any other desired material. Substrate 26 may include thin film transistor circuitry for applying control signals to the pixels and may therefore sometimes be referred to as a thin film transistor substrate. Figure 4 A red pixel 22 -R, a blue pixel 22 -B, and a green pixel 22 -G are shown.

[0033] Anodes 42, such as anodes 42-R, 42-G, and 42-B, may be formed on substrate 26. Anodes 42-R, 42-G, and 42-B may be formed of a conductive material and may be covered by OLED layer 45 and cathode 54. OLED layer 45 may include one or more layers for forming an organic light emitting diode. For example, layer 45 may include one or more of a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL). OLED layer 45 may be formed of a combination of a white OLED layer (e.g., an OLED layer configured to emit white light), red, green, blue, and / or yellow OLED layers, and the like. Cathode 54 may be a conductive layer formed on OLED layer 45. Cathode layer 54 may form a common cathode terminal for all diodes in display 14 (see, e.g., Figure 3 Each anode in display 14 can be independently controlled, so that each diode in display 14 can be independently controlled. This allows each pixel 22 to produce an independently controlled amount of light.

[0034] In some OLED displays, cathode 54 is completely (or nearly completely) transparent, and anode 42 may be in direct contact with OLED layer 45. However, Figure 4 Displays use optical cavities to improve efficiency and color purity in displays. Figure 4 The optical cavity in allows the uniform white OLED layer 45 to provide red light, green light, and blue light from the red pixel 22-R, the green pixel 22-G, and the blue pixel 22-B, respectively. The optical cavity can be formed by a reflective layer formed on either side of the OLED layer within the display. By adjusting the thickness of the optical cavity including the OLED layer, each pixel can be optimized to have high emission at a desired wavelength. To form this type of optical cavity, Figure 4 The display 14 in includes a partially transparent cathode layer 54 and an additional anode portion 44.

[0035] The cathode layer 54 may be formed of a partially transparent conductive material. In an illustrative example, the cathode layer 54 may be formed of a combination of magnesium (Mg) and silver (Ag). The cathode layer 54 may be formed of any other desired conductive material or combination of conductive materials. The cathode 54 may transmit less than 90% of light, may transmit less than 80% of light, may transmit less than 70% of light, may transmit less than 60% of light, may transmit less than 50% of light, may transmit more than 40% of light, may transmit more than 50% of light, may transmit more than 60% of light, may transmit between 40% and 80% of light, may transmit between 45% and 60% of light, may transmit between 60% and 70% of light, may transmit between 50% and 75% of light, etc. Cathode 54 may reflect more than 10% of the light, may reflect more than 20% of the light, may reflect more than 30% of the light, may reflect more than 40% of the light, may reflect more than 50% of the light, may reflect more than 60% of the light, may reflect less than 50% of the light, may reflect less than 60% of the light, may reflect between 20% and 60% of the light, may reflect between 40% and 55% of the light, may reflect between 30% and 40% of the light, may reflect between 25% and 50% of the light, etc.

[0036] Cathode layer 54 may define a first boundary of the optical cavity. Another boundary of the optical cavity may be set by anode 42 (sometimes referred to as anode portion 42). Anodes 42-R, 42-G, and 42-B may be formed of a high reflectivity material such as aluminum, silver, or any other desired conductive material. Each anode 42 may reflect more than 70% of the light, more than 80% of the light, more than 90% of the light, more than 95% of the light, more than 99% of the light, etc.

[0037] Additional layers may be formed on top of the anode 42 between the anode and the OLED layer 45. However, these additional layers may be transparent and therefore do not disrupt the optical cavity. Because the additional layers are transparent, the boundaries of the optical cavity are still determined by the reflective anode 42 and cathode 54. The presence of additional transparent layers between the anode 42 and cathode 54 may result in an increased distance between the reflective anode 42 and cathode 54 (because the OLED thickness is uniform). Figure 4 Pixel 22-R is shown having an optical cavity with a thickness of 48-R between anode 42-R and cathode 54. Pixel 22-G has an optical cavity with a thickness of 48-G between anode 42-G and cathode 54. Pixel 22-B has an optical cavity with a thickness of 48-B between anode 42-B and cathode 54.

[0038] The thickness of each optical cavity is adjusted to optimize the emission of the desired light color for that pixel. For a given optical cavity thickness, light of a given wavelength will resonate due to multiple reflections from the walls of the optical cavity (e.g., cathode 54 and anode 42). The increase in emission at a given wavelength caused by resonance within the optical cavity can be referred to as the microcavity effect. Pixels optimized to induce this effect (such as Figure 4 The pixels in the microcavity OLED can be called microcavity OLED pixels.

[0039] Pixel 22-R has an optical cavity thickness 48-R that maximizes emission of red light. Pixel 22-G has an optical cavity thickness 48-G that maximizes emission of green light. Pixel 22-B has an optical cavity thickness 48-B that maximizes emission of blue light. The wavelength of blue light is shorter than green light, and the wavelength of green light is shorter than red light. In general, the thickness of the optical cavity may be proportional to the wavelength of the type of light to be emitted. Therefore, thickness 48-B is less than thickness 48-G, and thickness 48-G is less than thickness 48-R. This example is merely illustrative and may not be applicable to all display designs, as other factors such as the nodes of the cavity may affect the optical cavity.

[0040] Therefore, the thickness of each optical cavity is adjusted to optimize the emission of light. However, varying the thickness of each optical cavity during the manufacturing process may present difficulties. In order to reduce the complexity and cost of manufacturing microcavity OLED displays, an additional anode portion 44 may be included in each pixel. Figure 4 As shown, the red pixel 22-R has an additional anode portion 44-R, the green pixel 22-G has an additional anode portion 44-G, and the blue pixel 22-B has an additional anode portion 44-B. These additional anode portions 44 (sometimes referred to as supplementary anodes 44, anodes 44, etc.) can be formed of a transparent conductive material. The additional anode portions can be formed of indium tin oxide (ITO) or any other desired transparent conductive material. Because the additional anodes are transparent, they can be used to adjust the optical cavity thickness 48 of the pixel without disrupting the optical cavity between the anode 42 and the cathode 54.

[0041] A pixel definition layer 66 may be formed between each pixel. The pixel definition layer may be formed of a non-conductive material and may be interposed between adjacent anodes of the display. The pixel definition layer may be formed of a non-conductive material (opaque or transparent) and may have openings formed therein with the anodes therein, thereby defining the area of ​​each pixel.

[0042] Additional layers may be included between anode portion 44 and anode portion 42 in each pixel. Figure 4As shown, a first dielectric layer 50 and a second dielectric layer 52 (sometimes referred to as spacers 50 and 52) are included in the display 14. The dielectric layer 52 has a portion formed over the anode 42-R in the red pixel 22-R. The dielectric layer 50 has a first portion formed over the anode 42-R in the red pixel 22-R and a second portion formed over the anode 42-G in the green pixel 22-G. The first portion of the dielectric layer 50 is interposed between the dielectric layer 52 and the supplemental anode 44-R. The second portion of the dielectric layer 50 is interposed between the anode 42-G and the supplemental anode 44-G.

[0043] Dielectric layers 50 and 52 and supplemental anode 44 may all be transparent or substantially transparent. This allows these layers to act as spacers, the thickness of which may be selected to adjust the thickness of the optical cavity of each pixel. Dielectric layers 50 and 52 and supplemental anode 44 may transmit more than 90% of incident light, more than 95% of incident light, more than 99% of incident light, more than 99.9% of incident light, etc. Dielectric layers 50 and 52 may be formed of silicon dioxide, silicon oxynitride, another desired oxide material, silicon nitride, or any other desired transparent material.

[0044] Dielectric layers 50 and 52 may serve as spacer structures that allow the cavity thickness 48 for each pixel to be adjusted. For ease of manufacturing, it is desirable that a white OLED layer 45 of uniform thickness is formed over each supplemental anode 44. In this way, the OLED layer 45 may be formed in a single deposition step, rather than being patterned with different thicknesses and / or different colors of OLED material for each pixel. Figure 4 As shown, the OLED thickness 56 -R of pixel 22 -R, the OLED thickness 56 -G of pixel 22 -G, and the OLED thickness 56 -B of pixel 22 -B are substantially the same (eg, within 5%).

[0045] Without the spacer layers 50 and 52, the supplemental anode 44, and the conductive spacer 68, OLED layers having uniform thickness would result in the same optical cavity thickness for each pixel. Figure 4 The inclusion of dielectric spacers and supplemental anodes as shown allows the optical cavity thickness to be tuned for the desired color.

[0046] Supplementary anode 44 may be electrically connected to anode 42. Figure 4 As shown, a via 60 may be formed that extends through dielectric layers 50 and 52 to electrically connect anode portion 44-R to anode portion 42-R. Figure 4 , via 60 includes a conductive portion 62 and a conductive liner 64. Another via having the same structure (eg, having a conductive portion and a conductive liner) is also formed through dielectric layer 50 to electrically connect supplemental anode 44-G to anode 42-G.

[0047] Unlike pixels 22-R and 22-G, pixel 22-B may not include a through hole. On the contrary, a conductive layer 68 may be inserted between anode portions 42-B and 44-B. Conductive layer 68 may electrically connect anode portion 42-B and anode portion 44-B and may be in direct contact with anode portion 42-B and anode portion 44-B. Conductive layer 68 (sometimes referred to as conductive spacer 68) may be included to avoid incompatibility between anode portion 44-B and anode portion 42-B. Conductive layer 68 may also promote better electrical contact between anode portion 44 and anode portion 42. For example, transparent anode portion 44-B may be formed by a material that corrodes when in direct contact with the material of reflective anode portion 42-B. For example, transparent anode portion 44-B may be formed by ITO, and reflective anode portion 42-B may be formed by aluminum. In this example, conductive spacer 68 may be inserted between anode portions to prevent corrosion.

[0048] Conductive layer 68 may be formed of titanium nitride (TiN) or another desired conductive material. Conductive layer 68 may be thin enough to be nearly transparent. For example, conductive layer 68 may have a thickness of less than 10 nanometers, less than 5 nanometers, less than 3 nanometers, between 2 nanometers and 5 nanometers, between 1 nanometer and 6 nanometers, between 2 nanometers and 3 nanometers, between 1 nanometer and 3 nanometers, etc. Conductive layer 68 may transmit more than 80% of incident light, more than 90% of incident light, more than 95% of incident light, more than 99% of incident light, more than 99.9% of incident light, etc.

[0049] exist Figure 4 In the embodiment of the present invention, no dielectric spacer is formed between anode portion 42-B and anode portion 44-B. Forming supplemental anode portion 44-B directly over anode portion 42-B along with intermediate conductive layer 68 eliminates the need to include a dielectric layer in the anode stack of pixel 22-B. This is beneficial because the dielectric spacer in the anode stack of a blue pixel must be very thin, which introduces manufacturing difficulties.

[0050] Additionally, forming supplemental anode portion 44-B directly over anode portion 42-B without an intervening dielectric layer allows for omitting via 60 (e.g., through a dielectric layer) in pixel 22-B. Omitting vias in blue pixel 22-B allows for increasing the aperture ratio of the blue pixel. The aperture of a pixel is the area from which light is emitted from the pixel. Figure 4 In the display shown, the opening of each pixel is defined by the pixel definition layer 66 (e.g., the opening corresponds to the area not covered by the opaque pixel definition layer). The aperture ratio refers to the ratio of the opening of the pixel (e.g., the light-emitting area) to the non-light-emitting area of ​​the pixel. Generally speaking, it is desirable to have a larger aperture ratio because a larger aperture ratio corresponds to higher display efficiency and improved display performance.

[0051] like Figure 4 As shown, the through hole 60 in the pixel 22-R and 22-G is a non-luminous area and is therefore covered by the pixel definition layer 66. The presence of the through hole 60 reduces the aperture ratio of the pixel. Figure 4 Omitting the through hole 60 in the blue pixel improves the aperture ratio of the blue pixel 22-B.

[0052] In some cases, anode portions 42-B and 44-B may be formed of materials that are compatible when in direct contact. For example, anode portion 42-B may be formed of silver, while anode portion 44-B may be formed of ITO. In this example, conductive layer 68 may be omitted, and anode portion 42-B may be formed in direct contact with anode portion 44-B.

[0053] The conductive portion 62 of each via 60 may optionally be formed of the same material as the supplemental anode portion 44. For example, if the supplemental anode 44-R of the pixel 22-R is formed of indium tin oxide, the conductive portion 62 of the via 60 in the pixel 22-R may also be formed of indium tin oxide. However, as discussed in conjunction with the conductive spacer 68, the indium tin oxide may not be placed in direct contact with the aluminum anode portion 42-R to prevent corrosion. Therefore, a conductive liner 64 may be interposed between the conductive via portion 62 and the anode portion 42-R. The conductive liner 64 may be formed of the same material as the conductive layer 68 (e.g., titanium nitride). In fact, the conductive liner 64 may be formed during the same deposition step as the conductive layer 68 during the display manufacturing process. Similar to the way that the conductive layer 68 may be omitted from the display based on material compatibility, the conductive liner 64 may be omitted if the conductive via portion 62 is compatible with the anode portion 42.

[0054] Each layer in display 14 may have any desired thickness. In some arrangements, supplemental anode portions 44-R, 44-G, and 44-B may have the same thickness. Each supplemental anode portion may have a thickness of less than 100 nanometers, less than 50 nanometers, less than 30 nanometers, less than 20 nanometers, less than 15 nanometers, less than 10 nanometers, greater than 5 nanometers, between 5 nanometers and 50 nanometers, between 5 nanometers and 100 nanometers, etc. Similarly, each of dielectric layers 50 and 52 may have any desired thickness (e.g., less than 100 nanometers, less than 50 nanometers, less than 30 nanometers, less than 20 nanometers, less than 15 nanometers, less than 10 nanometers, greater than 5 nanometers, between 5 nanometers and 50 nanometers, between 5 nanometers and 100 nanometers, etc.).

[0055] The supplementary anode and the lower layer between the supplementary anode and the anode may be referred to as an anode stack. For example, pixel 22-R has an anode stack including a supplementary anode 44-R, a dielectric layer 50 (sometimes referred to as an oxide layer 50), and a dielectric layer 52 (sometimes referred to as an oxide layer 52). The total thickness 70-R of the anode stack is adjusted to determine the total optical cavity thickness 48-R. Pixel 22-G has an anode stack including a supplementary anode 44-G and a dielectric layer 50. The total thickness 70-G of the anode stack is adjusted to determine the total optical cavity thickness 48-G. Pixel 22-B has an anode stack including a supplementary anode 44-B and an (optional) conductive spacer 68. The total thickness 70-B of the anode stack is adjusted to determine the total optical cavity thickness 48-B. In one arrangement, the thickness 70-R of the anode stack of the red pixel 22-R may be between 100 nanometers and 200 nanometers, the thickness 70-G of the anode stack of the green pixel 22-G may be between 70 nanometers and 100 nanometers, and the thickness 70-B of the anode stack of the blue pixel 22-B may be between 10 nanometers and 30 nanometers. These thickness values ​​are merely illustrative. Each anode stack may have any desired thickness (e.g., greater than 200 nanometers, between 100 nanometers and 150 nanometers, between 50 nanometers and 125 nanometers, less than 100 nanometers, less than 50 nanometers, less than 25 nanometers, less than 20 nanometers, etc.).

[0056] Figure 4 The display has the above advantages, namely, the through hole in pixel 22-B is omitted to improve the aperture ratio. In addition, the number of deposited layers is minimized to reduce manufacturing complexity and cost. Dielectric layer 52, dielectric layer 50, conductive layers for liner 64 and layer 68, and conductive layers for supplementary anode 44 can be deposited with a generally uniform thickness across the display, thereby reducing the need for additional patterning steps.

[0057] Wherein the white OLED layer 65 is uniformly deposited for the pixels 22-R, 22-G and 22-B Figure 4 The examples are merely illustrative. In some designs, each pixel may have a corresponding OLED layer for that color. For example, red pixel 22-R may have a red OLED layer (e.g., an OLED layer that emits red light), green pixel 22-G may have a green OLED layer (e.g., an OLED layer that emits green light), and blue pixel 22-B may have a blue OLED layer (e.g., an OLED layer that emits blue light). This type of arrangement may improve efficiency at the expense of increased manufacturing complexity.

[0058] Figure 5 is similar to Figure 4 A cross-sectional side view of a display having a microcavity OLED pixel of a display of FIG. 1 is shown in FIG. 1 . For simplicity, this article will not repeat the examples that are applicable to both Figure 4 and Figure 5 Repeated description of . Figure 5 In the example, each pixel consists of something like Figure 4 The transparent supplementary anode 44 in FIG. Figure 5 In the embodiment of the present invention, the thickness of the supplemental anodes is different. For example, supplemental anode 44-R may have a different thickness than supplemental anodes 44-G and 44-B (e.g., greater than that). This allows the combined thickness of dielectric layers 50 and 52 in pixel 22-R to be reduced while achieving the same anode stack height 70-R.

[0059] Reducing the thickness of dielectric layers 50 and 52 may be beneficial because it results in a shorter via 60 in pixel 22-R. Extending via 60 through thick dielectric layers may present challenges. Making vias that are both thin and deep may increase manufacturing costs, may increase manufacturing complexity, and may cause reliability issues. The vias may be made wider to more easily manufacture the same depth, but this may sacrifice the aperture ratio of the pixel.

[0060] By reducing Figure 5 The through hole 60 in pixel 22-R has the same depth as the through hole 60 in pixel 22-G. Therefore, the through holes of pixels 22-R and 22-G can be manufactured in the same processing step, thereby reducing the cost and complexity of manufacturing.

[0061] By adjusting the supplemental anode thickness, the desired anode stack thickness 70 and optical cavity thickness 48 can remain unaffected even if the thickness of the dielectric layer is reduced.

[0062] exist Figure 5 In the embodiment of the present invention, the blue pixel 22-B has a supplementary anode 44-B separated from the anode 42-B by a portion of the dielectric layer 50. The blue pixel has a through hole 60, which extends through the dielectric layer to electrically connect the anode portion 44-B to the anode portion 42-B. This type of arrangement allows the dielectric layer 50 to have the same thickness in the pixels 22-R, 22-G and 22-B. The thickness of the dielectric layer 50 can be selected mainly based on the adjustment of the anode stack of the pixel 22-B. The thickness of the dielectric layer 52 and the supplementary anode 44 can then be used to adjust the total thickness of the anode stack of the pixels 22-R and 22-G.

[0063] If desired, color filter elements may optionally be formed on Figure 4 and Figure 5For example, a red color filter element may be formed over each red pixel 22-R, a green color filter element may be formed over each green pixel 22-G, and a blue color filter element may be formed over each blue pixel 22-B. If desired, color filter elements may not be included in the display.

[0064] In addition, Figure 4 and Figure 5 , an example is shown in which a continuous OLED layer 45 is formed across the entire display. This example is merely illustrative. It should be understood that if desired, a pixel definition layer 66 and / or other structures may be used to form discontinuities in one or more OLED layers. Forming discontinuities in the OLED layers may prevent light leakage between pixels.

[0065] It should be understood that if necessary, the Figure 4 and Figure 5 For example, Figure 5 Rather than having a dielectric layer including a via (e.g., Figure 5 The pixel 22-B in may alternatively have Figure 4 2-B in the structure of pixel 22).

[0066] exist Figure 4 In the example of FIG. 4 , conductive spacer 68 is depicted as being formed only in the anode stack of blue pixel 42-B. This example is merely illustrative. If desired, red and / or green pixels may also include conductive spacers between the corresponding anode portion 42 and supplemental anode portion 44. In general, any subset of red, green, and blue pixels may include conductive spacers between the anode portions (and omit dielectric spacers between the anode portions).

[0067] Figure 6 is a cross-sectional side view of an exemplary display in which red, blue, and green pixels all have conductive spacers between corresponding anode portions. For simplicity, this document will not repeat the Figure 6 and a repeated description of one or more previous figures. Figure 6 In the example, each pixel consists of something like Figure 4 The transparent supplementary anode 44 in FIG. Figure 6In the embodiment of the present invention, the thickness of the supplementary anode is different. For example, the supplementary anode 44-R may have a different thickness than the supplementary anode 44-G and the supplementary anode 44-B (e.g., greater than it). The supplementary anode 44-G may have a different thickness than the supplementary anode 44-B (e.g., greater than it). The use of supplementary anodes 44 of varying thickness allows the total optical cavity thickness 48 to be optimized for each pixel type (e.g., pixel 22-R has an optical cavity thickness 48-R that maximizes the emission of red light, pixel 22-G has an optical cavity thickness 48-G that maximizes the emission of green light, and pixel 22-B has an optical cavity thickness 48-B that maximizes the emission of blue light), while allowing the OLED thicknesses 56-R, 56-G, and 56-B to remain approximately the same.

[0068] exist Figure 6 In the embodiment of the present invention, for each pixel, there is no intermediate dielectric layer between the transparent supplementary anode portion 44 and the anode portion 42. On the contrary, the conductive layer 68 can be inserted between the anode portions 42 and 44. As shown, the conductive layer 68-R is inserted between the anode portion 44-R and the anode portion 42-R, the conductive layer 68-G is inserted between the anode portion 44-G and the anode portion 42-G, and the conductive layer 68-B is inserted between the anode portion 44-B and the anode portion 42-B. The conductive layer 68 can electrically connect the corresponding anode portions 42 and 44 and can be in direct contact with the anode portion 42 and the anode portion 44. Conductive layers 68-R, 68-G and 68-B (sometimes referred to as conductive spacers) can be included to avoid incompatibility between the anode portion 44 and the anode portion 42. The conductive layer 68 can also promote better electrical contact between the anode portion 44 and the anode portion 42. For example, transparent anode portion 44 may be formed of a material that corrodes when in direct contact with the material of reflective anode portion 42 (e.g., transparent anode portion 44 may be formed of ITO, while reflective anode portion 42 may be formed of aluminum). In this example, conductive spacers 68 may be interposed between the anode portions to prevent corrosion.

[0069] Each of the conductive layers 68-R, 68-G, and 68-B may be formed of titanium nitride (TiN) or another desired conductive material. Each of the conductive layers 68-R, 68-G, and 68-B may be thin enough to be nearly transparent (e.g., may have a thickness of less than 10 nanometers, less than 5 nanometers, less than 3 nanometers, between 2 nanometers and 5 nanometers, between 1 nanometer and 6 nanometers, between 2 nanometers and 3 nanometers, between 1 nanometer and 3 nanometers, etc.). Each of the conductive layers 68-R, 68-G, and 68-B may transmit more than 80% of the incident light, more than 90% of the incident light, more than 95% of the incident light, more than 99% of the incident light, more than 99.9% of the incident light, etc. If desired, the conductive layers 68-R, 68-G, and 68-B may have a uniform thickness (e.g., Figure 6) or may have different thicknesses.

[0070] Figure 6 An arrangement of the type shown in has the following advantages: Figure 4 and Figure 5 In addition, no conductive vias are required through the intermediate dielectric layer, thereby allowing the pixel aperture ratio to be increased relative to when vias are required. If the conductive material used to form anode portions 42 and 44 is suitable for direct contact, conductive spacer 68 can be omitted (e.g., from any of the red, green, and blue pixels). Figure 6 , where no intermediate dielectric layer is present) can be used for all three pixel color types (e.g. Figure 6 ), a pixel color type (such as Figure 4 ) or any two pixel color types.

[0071] According to one embodiment, a display is provided, comprising: a first pixel formed by a first anode, a cathode, and an organic light-emitting diode layer, the first anode comprising a first portion and a second portion, the second portion being electrically connected to the first portion and having a first thickness, and the first pixel having an optical cavity defined by a first distance between the first portion and the cathode; and a second pixel formed by a second anode, the cathode, and the organic light-emitting diode layer, the second anode comprising a third portion and a fourth portion, the fourth portion being electrically connected to the third portion and having a second thickness different from the first thickness, the second pixel having an optical cavity defined by a second distance between the third portion and the cathode, and the second distance being different from the first distance.

[0072] According to another embodiment, the organic light emitting diode layer has a given thickness over the second portion of the first anode, and the organic light emitting diode layer has the given thickness over the fourth portion of the second anode.

[0073] According to another embodiment, the first pixel includes a first dielectric layer and a second dielectric layer interposed between the first portion of the first anode and the second portion of the first anode.

[0074] According to another embodiment, the first pixel includes a first via extending through the first dielectric layer and the second dielectric layer to electrically connect the first portion and the second portion of the first anode.

[0075] According to another embodiment, the second pixel includes the first dielectric layer and the second dielectric layer, and the first dielectric layer and the second dielectric layer are interposed between the third portion of the second anode and the fourth portion of the second anode.

[0076] According to another embodiment, the second pixel includes a second through hole extending through the first dielectric layer and the second dielectric layer to electrically connect the third portion and the fourth portion of the second anode.

[0077] According to another embodiment, the first thickness is greater than the second thickness.

[0078] According to another embodiment, the first dielectric layer has a third thickness in the first pixel and a fourth thickness in the second pixel that is the same as the third thickness, and the second dielectric layer has a fifth thickness in the first pixel and a sixth thickness in the second pixel that is the same as the fifth thickness.

[0079] According to another embodiment, the display includes a third pixel formed by a third anode, the cathode and the organic light emitting diode layer, the third anode including a fifth portion and a sixth portion, the sixth portion being electrically connected to the fifth portion and having a seventh thickness different from the first thickness, the third pixel having an optical cavity defined by a third distance between the fifth portion and the cathode, and the third distance is different from the first distance and the second distance.

[0080] According to another embodiment, the third pixel includes the first dielectric layer, the first dielectric layer is inserted between the fifth portion of the third anode and the sixth portion of the third anode, the first dielectric layer has an eighth thickness in the third pixel that is the same as the third thickness and the fourth thickness, the first distance is greater than the second distance, the second distance is greater than the third distance, the organic light emitting diode layer is a white organic light emitting diode layer, the first pixel is a red pixel, the second pixel is a green pixel, and the third pixel is a blue pixel.

[0081] According to another embodiment, the display includes a third pixel formed by a third anode, the cathode and the organic light emitting diode layer, the third anode including a fifth portion and a sixth portion, the sixth portion being electrically connected to the fifth portion and having a third thickness different from the first thickness and the second thickness, the third pixel having an optical cavity defined by a third distance between the fifth portion and the cathode, and the third distance is different from the first distance and the second distance.

[0082] According to another embodiment, the first pixel includes a first conductive layer inserted between the first portion and the second portion and in direct contact with the first portion and the second portion, the second pixel also includes a second conductive layer inserted between the third portion and the fourth portion and in direct contact with the third portion and the fourth portion, and the third pixel also includes a third conductive layer inserted between the fifth portion and the sixth portion and in direct contact with the fifth portion and the sixth portion.

[0083] According to one embodiment, a display is provided, the display including a pixel, the pixel including: an anode, the anode including a first portion formed of a first material and a second portion formed of a second material different from the first material; a cathode; an organic light emitting diode layer, the organic light emitting diode layer inserted between the second portion of the anode and the cathode; and a conductive spacer, the conductive spacer is formed of a third material different from the first material and the second material, the conductive spacer is inserted between the first portion and the second portion of the anode and electrically connects the first portion and the second portion of the anode, and the pixel has an optical cavity defined by the distance between the first portion of the anode and the cathode.

[0084] According to another embodiment, the pixel is a first pixel, the anode is a first anode, and the display includes a second pixel, the second pixel including: a second anode, the second anode including a third portion and a fourth portion; the cathode; the organic light emitting diode layer, the organic light emitting diode layer is inserted between the fourth portion of the second anode and the cathode; and at least one dielectric layer, the at least one dielectric layer is inserted between the third portion and the fourth portion of the second anode.

[0085] According to another embodiment, the at least one dielectric layer includes a first dielectric layer, and the first dielectric layer is the only dielectric layer interposed between the third portion and the fourth portion of the second anode.

[0086] According to another embodiment, the display includes a third pixel, the third pixel including: a third anode, the third anode including a fifth portion and a sixth portion; the cathode; the organic light emitting diode layer, the organic light emitting diode layer is inserted between the sixth portion of the third anode and the cathode; and two dielectric layers, the two dielectric layers are inserted between the fifth portion and the sixth portion of the third anode.

[0087] According to another embodiment, the second pixel includes a first through hole extending through the first dielectric layer to couple the third portion of the second anode to the fourth portion of the second anode, the third pixel includes a second through hole extending through the two dielectric layers to couple the fifth portion of the third anode to the sixth portion of the third anode, and the first pixel does not include any dielectric layer between the first portion of the first anode and the second portion of the first anode.

[0088] According to another embodiment, the optical cavity is a first optical cavity and the distance is a first distance, the second pixel has a second optical cavity defined by a second distance between the third portion of the second anode and the cathode, the third pixel has a third optical cavity defined by a third distance between the fifth portion of the third anode and the cathode, the first distance is less than the second distance, and the second distance is less than the third distance.

[0089] According to one embodiment, a display is provided, the display comprising a first pixel and a second pixel, the first pixel and the second pixel having a common cathode formed above an organic light emitting diode layer, wherein each of the first pixel and the second pixel comprises: a first anode portion; a second anode portion contacting the organic light emitting diode layer, the organic light emitting diode layer having a thickness above the second anode portion of the first pixel, and the organic light emitting diode layer having the thickness above the second anode portion of the second pixel; and at least one dielectric layer interposed between the first anode portion and the second anode portion, wherein the second anode portion of the first pixel and the second anode portion of the second pixel have different thicknesses.

[0090] According to another embodiment, the first anode portion of each of the first pixel and the second pixel is reflective, and the second anode portion of each of the first pixel and the second pixel is transparent.

[0091] The foregoing is merely illustrative, and various modifications may be made by those skilled in the art without departing from the scope and spirit of the embodiments described. The foregoing embodiments may be implemented independently or in any combination.

Claims

1. A display, comprising: a first pixel formed by a first anode, a cathode, and an organic light emitting diode layer, wherein the first anode includes a first portion and a second portion, wherein the second portion is electrically connected to the first portion and has a first thickness, wherein the first pixel has an optical cavity defined by a first distance between the first portion and the cathode, and wherein the first pixel includes a first dielectric layer and a second dielectric layer interposed between the first portion of the first anode and the second portion of the first anode; as well as A second pixel formed by a second anode, the cathode, and the organic light emitting diode layer, wherein the second anode includes a third portion and a fourth portion, wherein the fourth portion is electrically connected to the third portion and has a second thickness different from the first thickness, wherein the second pixel has an optical cavity defined by a second distance between the third portion and the cathode, and wherein the second distance is different from the first distance. 2 . The display according to claim 1 , wherein the organic light emitting diode layer has a given thickness over the second portion of the first anode, and wherein the organic light emitting diode layer has the given thickness over the fourth portion of the second anode. 3 . The display of claim 1 , wherein the first pixel comprises a first via extending through the first dielectric layer and the second dielectric layer to electrically connect the first portion and the second portion of the first anode.

4. The display of claim 3, wherein the second pixel comprises the first dielectric layer and the second dielectric layer, and wherein the first dielectric layer and the second dielectric layer are interposed between the third portion of the second anode and the fourth portion of the second anode. 5 . The display of claim 4 , wherein the second pixel includes a second via extending through the first dielectric layer and the second dielectric layer to electrically connect the third portion and the fourth portion of the second anode. The display according to claim 5 , wherein the first thickness is greater than the second thickness.

7. A display according to claim 6, wherein the first dielectric layer has a third thickness in the first pixel and has a fourth thickness in the second pixel that is the same as the third thickness, and wherein the second dielectric layer has a fifth thickness in the first pixel and has a sixth thickness in the second pixel that is the same as the fifth thickness.

8. The display according to claim 7, further comprising: A third pixel formed by a third anode, the cathode, and the organic light emitting diode layer, wherein the third anode includes a fifth portion and a sixth portion, wherein the sixth portion is electrically connected to the fifth portion and has a seventh thickness different from the first thickness, wherein the third pixel has an optical cavity defined by a third distance between the fifth portion and the cathode, and wherein the third distance is different from the first distance and the second distance.

9. The display of claim 8 , wherein the third pixel includes the first dielectric layer, wherein the first dielectric layer is interposed between the fifth portion of the third anode and the sixth portion of the third anode, wherein the first dielectric layer has an eighth thickness in the third pixel that is the same as the third thickness and the fourth thickness, wherein the first distance is greater than the second distance, wherein the second distance is greater than the third distance, wherein the organic light emitting diode layer is a white organic light emitting diode layer, wherein the first pixel is a red pixel, wherein the second pixel is a green pixel, and wherein the third pixel is a blue pixel.

10. The display according to claim 1, further comprising: A third pixel formed by a third anode, the cathode, and the organic light emitting diode layer, wherein the third anode includes a fifth portion and a sixth portion, wherein the sixth portion is electrically connected to the fifth portion and has a third thickness different from the first thickness and the second thickness, wherein the third pixel has an optical cavity defined by a third distance between the fifth portion and the cathode, and wherein the third distance is different from the first distance and the second distance.

11. A display according to claim 10, wherein the first pixel further includes a first conductive layer interposed between the first portion and the second portion and in direct contact with the first portion and the second portion, wherein the second pixel further includes a second conductive layer interposed between the third portion and the fourth portion and in direct contact with the third portion and the fourth portion, and wherein the third pixel further includes a third conductive layer interposed between the fifth portion and the sixth portion and in direct contact with the fifth portion and the sixth portion.

12. A display comprising: A pixel, the pixel comprising: an anode including a first portion formed of a first material and a second portion formed of a second material different from the first material; cathode; an organic light emitting diode layer interposed between the second portion of the anode and the cathode; and A conductive spacer, wherein the conductive spacer is formed of a third material different from the first material and the second material, wherein the conductive spacer is interposed between the first portion and the second portion of the anode and electrically connects the first portion and the second portion of the anode, and wherein the pixel has an optical cavity defined by a distance between the first portion of the anode and the cathode.

13. The display of claim 12, wherein the pixel is a first pixel, wherein the anode is a first anode, and wherein the display further comprises: A second pixel, the second pixel comprising: a second anode, the second anode comprising a third portion and a fourth portion; the cathode; the organic light emitting diode layer, wherein the organic light emitting diode layer is interposed between the fourth portion of the second anode and the cathode; and At least one dielectric layer is interposed between the third portion and the fourth portion of the second anode.

14. The display of claim 13, wherein the at least one dielectric layer comprises a first dielectric layer, and wherein the first dielectric layer is the only dielectric layer interposed between the third portion and the fourth portion of the second anode.

15. The display according to claim 14, further comprising: A third pixel, the third pixel comprising: a third anode, the third anode comprising a fifth portion and a sixth portion; the cathode; the organic light emitting diode layer, wherein the organic light emitting diode layer is interposed between the sixth portion of the third anode and the cathode; and Two dielectric layers are interposed between the fifth portion and the sixth portion of the third anode.

16. The display of claim 15 , wherein the second pixel comprises a first through hole extending through the first dielectric layer to couple the third portion of the second anode to the fourth portion of the second anode, wherein the third pixel comprises a second through hole extending through the two dielectric layers to couple the fifth portion of the third anode to the sixth portion of the third anode, and wherein the first pixel does not include any dielectric layer between the first portion of the first anode and the second portion of the first anode.

17. The display of claim 16, wherein the optical cavity is a first optical cavity and the distance is a first distance, wherein the second pixel has a second optical cavity defined by a second distance between the third portion of the second anode and the cathode, wherein the third pixel has a third optical cavity defined by a third distance between the fifth portion of the third anode and the cathode, wherein the first distance is less than the second distance, and wherein the second distance is less than the third distance.

18. A display comprising: A first pixel and a second pixel, the first pixel and the second pixel having a common cathode formed over an organic light emitting diode layer, wherein each of the first pixel and the second pixel comprises: a first anode portion; a second anode portion, wherein the second anode portion is electrically connected to the first anode portion, the second anode portion contacts the organic light emitting diode layer, wherein the organic light emitting diode layer has a thickness over the second anode portion of the first pixel, and wherein the organic light emitting diode layer has the thickness over the second anode portion of the second pixel; and At least one dielectric layer is interposed between the first anode portion and the second anode portion, wherein the second anode portion of the first pixel and the second anode portion of the second pixel have different thicknesses.

19. The display of claim 18, wherein the first anode portion of each of the first pixel and the second pixel is reflective, and wherein the second anode portion of each of the first pixel and the second pixel is transparent.

Images