PATENT DOCUMENT

Publication Number: US-10535840-B2
Application Number: US-201816167391-A
Country: US
Kind Code: B2

Title: Organic light-emitting diode displays

Abstract:
A display may have an array of pixels. Each pixel may have a light-emitting diode such as an organic light-emitting diode. The organic light-emitting diodes may each have a reflective electrode such as a metal anode and a partially reflective electrode such as a metal cathode. Emissive material may be formed between the electrodes. The electrodes of each organic light-emitting diode may form an optical cavity. A wrinkled layer may be formed over the optical cavity to reduce sensitivity to process variations associated with forming encapsulation structures for the display. The wrinkled layer may include annealed organic layers. The organic layers may wrinkle during an annealing process at an annealing temperature. The annealed organic layers may include a first organic layer with a glass transition temperature below the annealing temperature and a second organic layer with a glass transition temperature above the annealing temperature.

Claims:
What is claimed is: 
     
       1. A display, comprising:
 a substrate; 
 organic light-emitting diodes on the substrate, wherein each organic light-emitting diode has an optical cavity formed from first and second electrodes and has emissive material interposed between the first and second electrodes; 
 a wrinkled layer that includes a first layer of a first organic material and a second layer of a second organic material, wherein the wrinkled layer has a randomly-oriented pattern; and 
 encapsulation structures, wherein in each organic light-emitting diode the first electrode is interposed between the emissive material and the substrate, the second electrode is partially reflective and is interposed between the wrinkled layer and the emissive material, and the wrinkled layer is interposed between the second electrode and the encapsulation structures. 
 
     
     
       2. The display defined in  claim 1  wherein the first organic material and the second organic material have different glass transition temperatures. 
     
     
       3. The display defined in  claim 1  wherein in each organic light-emitting diode the first layer is interposed between the second layer and the second electrode of that organic light-emitting diode, wherein the first organic material has a first glass transition temperature, and wherein the second organic material has a second glass transition temperature that is larger than the first glass transition temperature. 
     
     
       4. The display defined in  claim 1  wherein the encapsulation structures comprise a glass layer. 
     
     
       5. The display defined in  claim 4  wherein the glass layer is separated from the wrinkled layer by an air gap. 
     
     
       6. The display defined in  claim 4  further comprising a polymer layer that separates the glass layer from the wrinkled layer. 
     
     
       7. The display defined in  claim 1  wherein the encapsulation structures include at least one thin-film encapsulation layer. 
     
     
       8. The display defined in  claim 1  wherein the encapsulation structures comprise:
 a first thin-film inorganic layer on the wrinkled layer; 
 a second thin-film inorganic layer; and 
 a polymer layer interposed between the first and second thin-film inorganic layers. 
 
     
     
       9. The display defined in  claim 1  wherein the organic light-emitting diodes each have a maximum lateral dimension, wherein the wrinkled layer has wrinkles characterized by a period, and wherein the maximum lateral dimension divided by the period is 3-30. 
     
     
       10. The display defined in  claim 1  wherein the wrinkled layer has wrinkles characterized by a period of 0.05 microns to 5 microns. 
     
     
       11. The display defined in  claim 10  wherein the first organic material has a first glass transition temperature and the second organic material has a second glass transition temperature that is greater than the first glass transition temperature. 
     
     
       12. The display defined in  claim 10  wherein the wrinkled layer is an organic annealed layer formed from the first organic material, which has a glass transition temperature below an annealing temperature, and formed from the second organic material, which has a glass transition temperature above the annealing temperature. 
     
     
       13. The display defined in  claim 12  wherein the first organic material is interposed between the second organic material and the second electrode of each light-emitting diode. 
     
     
       14. A light-emitting diode device, comprising:
 an optical cavity formed from a reflective electrode, a partially reflective electrode, and emissive material interposed between the reflective electrode and the partially reflective electrode; and 
 a wrinkled layer on the partially reflective electrode that includes a first organic layer with a first glass transition temperature and a second organic layer with a second glass transition temperature that is greater than the first glass transition temperature, wherein the partially reflective layer is interposed between the first organic layer and the emissive material. 
 
     
     
       15. The light-emitting diode device defined in  claim 14  further comprising encapsulation structures on the wrinkled layer that include first and second inorganic passivation layers and an organic layer interposed between the first and second inorganic passivation layers. 
     
     
       16. A display, comprising:
 a substrate; 
 organic light-emitting diodes on the substrate, wherein each organic light-emitting diode has an optical cavity formed from a reflective electrode and a partially reflective electrode and has emissive material interposed between the reflective electrode and the partially reflective electrode; 
 a wrinkled layer having a first organic layer with a first glass transition temperature covered with a second organic layer having a glass transition temperature that is higher than the first glass transition temperature; and 
 encapsulation structures that encapsulate the wrinkled layer and the organic light-emitting diodes. 
 
     
     
       17. The display defined in  claim 1  wherein the wrinkled layer forms cavities having a plurality of cavity lengths.

Description:
This application claims the benefit of provisional patent application No. 62/622,657, filed Jan. 26, 2018, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices, and, more particularly, to electronic devices with displays. 
     BACKGROUND 
     Electronic devices often include displays. Displays such as organic light-emitting diode displays have pixels with light-emitting diodes. The light emitting diodes each have electrodes (i.e., an anode and a cathode). Emissive material is interposed between the electrodes. During operation, current passes through the emissive material between the electrodes, generating light. 
     The pixels in organic light-emitting diode displays may include optical cavities. The presence of an optical cavity may enhance color performance and efficiency, but may make the performance of each pixel sensitive to process variations. For example, variations in encapsulation layer thickness may result in undesired color variations. 
     SUMMARY 
     A display may have an array of pixels. Each pixel may have a light-emitting diode such as an organic light-emitting diode. The organic light-emitting diodes may each have a reflective electrode such as a metal anode and a partially reflective electrode such as a metal cathode. Emissive material may be formed between the electrodes. The electrodes of each organic light-emitting diode may form an optical cavity. 
     A wrinkled layer may be formed on the partially reflective electrode to reduce sensitivity to process variations associated with forming encapsulation structures for the display. The wrinkled layer may include annealed organic layers. The organic layers may wrinkle during an annealing process at an annealing temperature. The annealed organic layers may include a first organic layer with a glass transition temperature below the annealing temperature and a second organic layer with a glass transition temperature above the annealing temperature. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device having a display in accordance with an embodiment. 
         FIG. 2  is a top view of an illustrative display in an electronic device in accordance with an embodiment. 
         FIG. 3  is a cross-sectional side view of a portion of an illustrative organic light-emitting diode display in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view of a portion of a partially fabricated organic light-emitting diode display in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of the portion of the organic light-emitting diode display of  FIG. 4  after additional processing in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of the portion of the organic light-emitting diode display of  FIG. 4  after additional processing with alternative process steps in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device of the type that may be provided with a display is shown in  FIG. 1 . As shown in  FIG. 1 , electronic device  10  may have control circuitry  16 . Control circuitry  16  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static 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. 
     Input-output circuitry in device  10  such as input-output devices  12  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  12  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, data ports, and other electrical components. A user can control the operation of device  10  by supplying commands through input-output devices  12  and may receive status information and other output from device  10  using the output resources of input-output devices  12 . 
     Input-output devices  12  may include one or more displays such as display  14 . Display  14  may be a touch screen display that includes a touch sensor for gathering touch input from a user or display  14  may be insensitive to touch. A touch sensor for display  14  may be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. 
     Control circuitry  16  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  16  may display images on display  14  using an array of pixels in display  14 . 
     Device  10  may be a tablet computer, laptop computer, a desktop computer, a display, a cellular telephone, a media player, a wristwatch device or other wearable electronic equipment, or other suitable electronic device. 
     Display  14  may be an organic light-emitting diode display or may be a display based on other types of display technology. Configurations in which display  14  is an organic light-emitting diode display are sometimes described herein as an example. If desired, organic light-emitting diodes may be used in non-display organic light-emitting diode devices (e.g., lighting devices). 
     Display  14  may have a rectangular shape (i.e., display  14  may have a rectangular footprint and a rectangular peripheral edge that runs around the rectangular footprint) or may have other suitable shapes. Display  14  may be planar or may have a curved profile. 
     A top view of a portion of display  14  is shown in  FIG. 2 . As shown in  FIG. 2 , display  14  may have an array of pixels  22  formed on substrate  36 . Substrate  36  may be formed from glass, metal, plastic, ceramic, or other substrate materials. Pixels  22  may receive data signals over signal paths such as data lines D and may receive one or more control signals over control signal paths such as horizontal control lines G (sometimes referred to as gate lines, scan lines, emission control lines, etc.). There may be any suitable number of rows and columns of pixels  22  in display  14  (e.g., tens or more, hundreds or more, or thousands or more). Each pixel  22  may have a light-emitting diode  26  that emits light  24  under the control of a pixel circuit formed from thin-film transistor circuitry such as thin-film transistors  28  and thin-film capacitors). Thin-film transistors  28  may be polysilicon thin-film transistors, semiconducting-oxide thin-film transistors such as indium gallium zinc oxide transistors, or thin-film transistors formed from other semiconductors. Pixels  22  may contain light-emitting diodes of different colors (e.g., red, green, and blue diodes for red, green, and blue pixels, respectively) to provide display  14  with the ability to display color images. 
     Display driver circuitry may be used to control the operation of pixels  22 . The display driver circuitry may be formed from integrated circuits, thin-film transistor circuits, or other suitable circuitry. Display driver circuitry  30  of  FIG. 2  may contain communications circuitry for communicating with system control circuitry such as control circuitry  16  of  FIG. 1  over path  32 . Path  32  may be formed from traces on a flexible printed circuit or other cable. During operation, the control circuitry (e.g., control circuitry  16  of  FIG. 1 ) may supply circuitry  30  with information on images to be displayed on display  14 . 
     To display the images on display pixels  22 , display driver circuitry  30  may supply image data to data lines D while issuing clock signals and other control signals to supporting display driver circuitry such as gate driver circuitry  34  over path  38 . If desired, circuitry  30  may also supply clock signals and other control signals to gate driver circuitry on an opposing edge of display  14 . 
     Gate driver circuitry  34  (sometimes referred to as horizontal control line control circuitry) may be implemented as part of an integrated circuit and/or may be implemented using thin-film transistor circuitry. Horizontal control lines G in display  14  may carry gate line signals (scan line signals), emission enable control signals, and other horizontal control signals for controlling the pixels of each row. There may be any suitable number of horizontal control signals per row of pixels  22  (e.g., one or more, two or more, three or more, four or more, etc.). 
     A cross-sectional side view of a portion of an illustrative organic light-emitting diode display that includes a light-emitting diode (diode  26 ) for a pixel and thin-film transistor circuitry for an associated pixel circuit (pixel circuit  48 ) is shown in  FIG. 3 . As shown in  FIG. 3 , display  14  may include a substrate layer such as substrate layer  36 . Substrate  36  may be a planar layer or a non-planar layer and may be formed from plastic, glass, ceramic, sapphire, metal, or other suitable materials. The surface of substrate  36  may, if desired, be covered with one or more buffer layers (e.g., inorganic buffer layers such as layers of silicon oxide, silicon nitride, etc.). 
     Thin-film transistor circuitry for pixel circuit  48  may be formed on substrate  36 . The thin film transistor circuitry may include transistors, capacitors, and other thin-film structures. As shown in  FIG. 3 , a transistor such as thin-film transistor  28  may be formed from thin-film semiconductor layer  60 . Semiconductor layer  60  may be a polysilicon layer, a semiconducting-oxide layer such as a layer of indium gallium zinc oxide, or other semiconductor layer. Gate layer  56  may be a conductive layer such as a metal layer that is separated from semiconductor layer  60  by an intervening layer of dielectric such as dielectric  58  (e.g., an inorganic gate insulator layer such as a layer of silicon oxide). Dielectric  62  may also be used to separate semiconductor layer  60  from underlying structures such as shield layer  64  (e.g., a shield layer that helps shield the transistor formed from semiconductor layer  60  from charge in buffer layers on substrate  36 ). 
     Semiconductor layer  60  of transistor  28  may be contacted by source and drain terminals formed from source-drain metal layer  52 . Dielectric layer  54  (e.g., an inorganic dielectric layer) may separate gate metal layer  56  from source-drain metal layer  52 . Pixel circuit  48  (e.g., source-drain metal layer  52 ) may be shorted to anode  42  of light-emitting diode  26  using a metal via such as via  53  that passes through dielectric planarization layer  50 . Planarization layer  50  may be formed from an organic dielectric material such as a polymer. 
     Light-emitting diode  26  is formed from light-emitting diode layers  40  on the thin-film transistor layers of pixel circuit  48 . Each light-emitting diode has a lower electrode such as anode  42  and an upper electrode such as cathode  46 . Display  14  may be a top emission display. In a top emission display, the lower electrode may be formed from a reflective conductive material such as patterned metal to help reflect light that is produced by the light-emitting diode in the upwards direction out of the display. The lower electrode may, as an example, be a reflective metal electrode formed from a silver alloy having a reflectivity of at least 98%, at least 99%, etc. The upper electrode (sometimes referred to as the counter electrode) may be formed from a partially reflective metal layer that forms an optical cavity for diode  26 . The upper electrode may, as an example, be formed from a magnesium silver alloy and may have a reflectivity of 50-70%, at least 40%, at least 55%, less than 80%, less than 75%, or other suitable reflectivity. 
     The partial reflectivity (partial transparency) of the upper electrode allows the upper electrode to transmit light outwards that has been produced by emissive material in the diode. Layers such as a hole injection layer, hole transport layer, emissive material layer, electron transport layer, and electron injection layer may be formed above the lower electrode and below the upper electrode. 
     In the illustrative configuration of  FIG. 3 , display  14  has a top emission configuration and lower electrode  42  is an anode and upper electrode  46  is a cathode. Layers  40  include a patterned metal layer that forms anodes such as anode  42 . Anode  42  is formed within an opening in pixel definition layer  66 . Pixel definition layer  66  may be formed from a patterned photoimageable polymer. The photoimageable polymer may be formed from an opaque material and/or a layer of opaque material such as black masking layer  66 ′ may cover other material in layer  66  (e.g., opaque layer  66 ′ may cover a layer of semitransparent polyimide or other polymer). 
     In each light-emitting diode, organic emissive material  44  is interposed between a respective anode  42  and cathode  46 . Anodes  42  may be patterned from a layer of metal on a planarization layer in the thin-film transistor layers of pixel circuit  48  such as planarization layer  50 . Cathode  46  may be formed from a common conductive layer that is deposited on top of pixel definition layer  66 . Cathode  46  is partially reflective and partially transparent so that light  24  may exit light emitting diode  26  as current is flowing through emissive material  44  between anode  42  and cathode  46 . In each diode, an optical cavity is formed from a partially reflective cathode  46  and reflective anode  42 . 
     To protect light-emitting diodes  26  and other circuitry in pixels  22 , pixels  22  may be covered with encapsulation structures (e.g., a glass layer or thin-film capping layer formed on the upper surface of display  14 ). The capping layer can contribute to the optical cavity of each light-emitting diode and therefore has the potential for influencing the color of light produced by each pixel. If care is not taken, process variations that arise when forming encapsulation for display  14  can cause variations in the properties of the optical cavities of light-emitting diodes  26  and therefore the color performance of display  14 . 
     To reduce the impact of process variations on display color performance, a wrinkled layer (sometimes referred to as a spinodal wrinkling structure) can be used as a capping layer for diodes  26 . Across the surface of the optical cavity of each diode  26 , the wrinkled layer effectively creates multiple smaller cavities with a variety of different cavity lengths. Taken together, these random cavity length variations reduce the impact of process variations in the passivation layers above the diodes on the color performance of the diodes. As a result, display  14  exhibits less sensitivity to encapsulation process variations. 
     Any suitable arrangement may be used in forming a wrinkled layer on display  14 . With one illustrative configuration, first and second layers of different respective organic materials are formed above diodes  26 . The first layer may be deposited on the surface of display  14  before the second layer. The first and second layers may be formed from materials of the type that are sometimes used in forming organic light-emitting diode emissive layers (e.g., hole transport layer materials, etc.) or other materials compatible with the formation of diodes  26 . The first layer may have a first glass transition temperature and the second layer may have a second glass transition temperature. The first glass transition temperature may be lower than the second glass transition temperature. By annealing the first and second layers at an annealing temperature between the first and second glass transition temperatures, the first and second layers may be caused to wrinkle. 
       FIG. 4  is a cross-sectional side view of a portion of display  14  after first layer  80  and second layer  82  of wrinkled layer  84  have been deposited prior to annealing. With one illustrative arrangement, first layer  80  may be an organic material such as TPD (N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine, which is sometimes used as a hole transport layer in organic light-emitting diodes, and may have a glass transition temperature of about 60° C. Second layer  82  may, as an example, be NPB (N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine) and may have a glass transition temperature of about 100° C. The thicknesses of the first and second layers may be about 10-200 nm, 2-1000 nm, at least 20 nm, at least 30 nm, at least 50 nm, at least 100 nm, less than 150 nm, less than 120 nm, less than 100 nm, less than 80 nm, less than 40 nm, or other suitable thicknesses. 
     After annealing at a temperature T between 60° C. and 100° C. (e.g., for 5-10 minutes), stresses are produced that cause first layer  80  and second layer  82  to wrinkle and form wrinkled layer  84  of  FIG. 5 . The period (peak-to-peak wrinkle size) of the wrinkles in layer  84  may be such that there are multiple wrinkles within each pixel area. For example, if each diode  26  has a lateral size of about 20-50 microns, the size of each wrinkle in layer  84  may be about 2-10 microns. The wrinkles may form a sinuous randomly-oriented pattern when viewed from above. Diode  26  may have a maximum lateral dimension of 20-50 microns, at least 15 microns, less than 75 microns, or other suitable size and the period of the wrinkles in wrinkled layer  84  may be such that the maximum lateral dimension divided by the period is 3-30, at least 2, at least 5, at least 10, less than 100, less than 50, less than 25, less than 20, less than 10, or other suitable amount. In general, it may be desirable for the period of the wrinkles in layer  84  to be greater than about one tenth of a wavelength of light (e.g., 0.05 microns, which is one tenth of 0.5 microns for green light) to ten times the wavelength of light (e.g., 5 microns for green light). The wrinkles of layer  84  may, for example, have a period of at least 0.1 micron, at least 0.5 microns, at least 1 micron, at least 2 microns, at least 4 microns, at least 5 microns, at least 10 microns, less than 20 microns, less than 15 microns, less than 8 microns, less than 3 microns, or other suitable size. The thickness of the wrinkles (crest-to-trough height difference) may be 0.05 microns to 10 microns, at least 0.1 microns, at least 0.5 microns, at least 1 micron, less than 20 microns, or other suitable size. If desired, wrinkled layer  84  may be used in larger light-emitting diodes used for lighting. For large light-emitting diodes such as diodes used in lighting, the dimensions of the wrinkles in wrinkled layer  84  can be enlarged accordingly. 
     The thickness variations imposed by the wrinkles in wrinkled layer  84  create optical cavity length variations for the optical cavities of diodes  26 . These optical cavity length variations are random and therefore help homogenize color variations that might otherwise arise from optical cavity variations in diodes  26 . As a result, the optical impact of process variations associated with forming encapsulation structures for display  14  (e.g., process variations leading to encapsulation thickness variations, etc.) may be reduced. 
     In the example of  FIG. 5 , wrinkled layer is covered with encapsulation structures such as glass layer  88 . A layer such as layer  86  (e.g., an air gap or a layer of polymer) may be interposed between glass encapsulation layer  88  and wrinkled layer  84 . 
     In the example of  FIG. 6 , encapsulation structures  90  have been formed from thin-film encapsulation layers such as passivation layer  92 , planarization layer  94 , and passivation layer  96 . First passivation layer  92  may be formed on the surface of wrinkled layer  84 . First passivation layer  92  may be formed from an inorganic dielectric layer such as a layer of silicon nitride or silicon oxynitride (as examples). The thickness of layer  92  may be about 0.5-2 microns, at least 0.3 microns, at least 0.8 microns, less than 3 microns, less than 1.5 microns, or other suitable thickness. Planarization layer  94  may be formed on passivation layer  92 . Planarization layer  94  may be formed from an organic material (e.g., a photo-cured or thermally cured liquid polymer). The thickness of planarization layer  94  may be 5-20 microns, at least 1.5 microns, at least 3 microns, at least 4 microns, less than 45 microns, less than 25 microns, less than 10 microns, or other suitable thickness. Second passivation layer  96  may be formed on layer  94  from an inorganic dielectric layer such as a layer of silicon nitride or silicon oxynitride (as examples). The thickness of layer  96  may be about 0.5-2 microns, at least 0.3 microns, at least 0.8 microns, less than 3 microns, less than 1.5 microns, or other suitable thickness. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20181022
Publication Date: 20200114
Grant Date: 20200114
Priority Date: 20180126
Inventors: CHEN, CHIEH-WEI
CHO, TING-YI
Assignee: APPLE INC
CPC Classifications: [{"code": "H01L51/5206", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L27/124", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L27/323", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L27/3246", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L51/5256", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L29/41733", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L51/5221", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L29/78633", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10D86/441", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10D86/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10D30/6729", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10D30/6723", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10D30/6729", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10D30/6723", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K59/40", "inventive": false, "first": false, "tree": "[]"}, {"code": "H10K59/122", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K50/8445", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K50/82", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K50/81", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/8051", "inventive": false, "first": false, "tree": "[]"}, {"code": "H10K59/876", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/8731", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/8052", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 67393728