Electronic device with moisture-insensitive optical touch sensor

Abstract

An electronic device can have a touch-sensitive display that is insensitive to the presence of moisture. An array of pixels in the display can be used to display an image. A display cover layer can overlap the array of pixels. A light source can illuminate an external object, such as a user's finger, when the object contacts a surface of the display cover layer. This creates scattered light that can be detected by an array of light sensors. The light source can provide light at an angle to an edge of the display cover layer that ensures total internal reflection within the display cover layer is maintained across the display cover layer, even when the display cover layer is submerged in water or otherwise exposed to moisture.

Description

[0001] This application claims priority to U.S. Patent Application No. 17 / 188,946, filed March 1, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates in general to electronic devices, and more specifically to electronic devices having touch sensors. Background Technology

[0003] Electronic devices such as tablets, cell phones, and other equipment sometimes incorporate touch sensors. For example, displays in electronic devices typically have capacitive touch sensors to receive touch input. Operating such sensors in humid conditions can be challenging. Summary of the Invention

[0004] This invention provides an electronic device that may have a touch-sensitive display that is insensitive to the presence of moisture. The display may have a two-dimensional optical touch sensor, such as a direct-illumination optical touch sensor or a total internal reflection touch sensor. The optical touch sensor can be used to collect touch input when the electronic device is immersed in water or otherwise exposed to moisture.

[0005] The pixel array in the display is used to display images. The display overlay can overlap the pixel array. A light source illuminates an external object, such as a user's finger, when it touches the surface of the display overlay. This produces scattered light that can be detected by an array of light sensors. The light source can direct light at an angle to the edges of the display overlay, an angle that ensures total internal reflection remains within the display overlay when it is immersed in water or otherwise exposed to moisture. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of an exemplary electronic device according to the implementation plan.

[0007] Figure 2 It is a perspective view of an exemplary electronic device according to the implementation plan.

[0008] Figure 3 It is a cross-sectional side view of an exemplary electronic device according to the implementation scheme.

[0009] Figure 4 This is a top view of an exemplary pixel array of an electronic device according to the implementation scheme.

[0010] Figure 5 and Figure 6 It is a cross-sectional side view of an exemplary pixel array for an electronic device according to an implementation scheme.

[0011] Figure 7This is a cross-sectional side view of an exemplary optical touch sensor arrangement according to the implementation scheme.

[0012] Figure 8 This is a cross-sectional side view of an exemplary optical touch sensor arrangement based on total internal reflection, according to the implementation scheme.

[0013] Figure 9 , Figure 10 and Figure 11 It is a cross-sectional side view of an exemplary display and sensor arrangement with different numbers of pixel layers according to the implementation scheme.

[0014] Figure 12 It is a cross-sectional side view of an exemplary pixel having a thin-film circuit structure according to the implementation scheme.

[0015] Figure 13 It is a cross-sectional side view of an exemplary pixel formed from a crystal semiconductor die according to the implementation scheme.

[0016] Figure 14 It is a cross-sectional side view of an exemplary light source configured to emit light into a display overlay through a refractive index matching structure, according to the implementation scheme.

[0017] Figure 15 , Figure 16 , Figure 17 , Figure 18 and Figure 19 This is a cross-sectional side view of an exemplary aperture that can be placed on a photodetector according to the implementation scheme.

[0018] Figure 20 and Figure 21 This is a timing diagram illustrating how the light-emitting pixels and photosensitive pixels can operate in an electronic device according to the implementation scheme.

[0019] Figure 22 It is a cross-sectional side view of an exemplary pixel array, which may include photosensitive pixels, according to the implementation scheme.

[0020] Figure 23 It is a cross-sectional side view of an exemplary display having an optical touch sensor formed by components located above and / or below an image pixel array, according to an embodiment.

[0021] Figure 24 This is a cross-sectional side view of an exemplary display having backlight unit pixels that can be used to form an optical touch sensor structure, according to an embodiment. Detailed Implementation

[0022] Figure 1 The diagram shows an exemplary electronic device that may include an optical touch sensor. Figure 1The electronic device 10 may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular phone, a media player, or other handheld or portable electronic device, a smaller device (such as a wristwatch or other device worn on a user's wrist), a hanging device, a headset or handset device, a head-mounted device (such as glasses, goggles, or other equipment worn on a user's head), or other wearable or micro-devices, a television set, a computer monitor that does not contain an embedded computer, a gaming device, a navigation device, an embedded system (such as a system in which electronic equipment with a display is installed in an information kiosk or a car), equipment that performs the functions of two or more of these devices, or other electronic equipment. The exemplary configuration of device 10 as a portable device such as a wristwatch, a cellular phone, or a tablet computer, and more specifically a water-resistant or waterproof portable device, may sometimes be described as an example herein.

[0023] like Figure 1 As shown, electronic device 10 may have control circuitry 16. Control circuitry 16 may include storage and processing circuitry for supporting the operation of device 10. Storage and processing circuitry may include storage devices such as hard disk drive storage devices, non-volatile memory (e.g., flash memory configured to form a solid-state drive or other electrically programmable read-only memory), volatile memory (e.g., static or dynamic random access memory), and so on. Processing circuitry in control circuitry 16 may be used to control the operation of device 10. 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. Control circuitry 16 may include communication circuitry for supporting wired and / or wireless communication between device 10 and external equipment. For example, control circuitry 16 may include wireless communication circuitry, such as cellular telephone communication circuitry and wireless local area network communication circuitry.

[0024] Input-output circuitry in device 10, such as input-output device 12, can 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 device 12 may include buttons, joysticks, scroll wheels, touchpads, keypads, keyboards, microphones, speakers, audio generators, haptic output devices, cameras, LEDs and other status indicators, data ports, etc. Users can control the operation of device 10 by providing commands via input-output device 12, and can use the output resources of input-output device 12 to receive status information and other outputs from device 10.

[0025] Input-output device 12 may include one or more displays, such as display 14. Display 14 may be an organic light-emitting diode display, a display formed from an array of crystal semiconductor light-emitting diode dies, a liquid crystal display, or other displays. Display 14 may be a touchscreen display including an optical touch sensor for acquiring touch input from a user. The optical touch sensor may be configured to operate even when device 10 is immersed in water or otherwise exposed to moisture. If desired, the optical touch sensor may also be configured to operate when the user is wearing gloves, which may be difficult or impossible for some capacitive touch sensors. Furthermore, because the optical touch sensor operates optically, it is unaffected by grounding effects that could affect the operation of capacitive touch sensors.

[0026] like Figure 1 As shown, input-output device 12 may include sensor 18. Sensor 18 may include a touch sensor. Touch sensors may be provided for display 14 and / or other parts of device 10 and may be formed by capacitive touch sensor electrode arrays, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, light-based touch sensor structures, or other suitable touch sensor arrangements. Exemplary optical touch sensor arrangements for device 10 (e.g., display 14 for device 10) are sometimes described herein as examples.

[0027] Sensor 18 may include capacitive sensors, light-based proximity sensors, magnetic sensors, accelerometers, force sensors, touch sensors, temperature sensors, pressure sensors, inertial measurement units, accelerometers, gyroscopes, compasses, microphones, radio frequency sensors, three-dimensional image sensors (e.g., structured light sensors with light emitters configured to emit structured light, such as infrared light emitters, and corresponding infrared image sensors, three-dimensional sensors based on pairs of two-dimensional image sensors, etc.), cameras (e.g., visible light cameras and / or infrared light cameras), light-based position sensors (e.g., lidar sensors), monochrome and / or color ambient light sensors, and other sensors. Sensors 18, such as ambient light sensors, image sensors, optical proximity sensors, lidar sensors, optical touch sensors, and other sensors that use light and / or emit light (such as status indicators and other light-emitting components), may sometimes be referred to as optical components.

[0028] Figure 2 A perspective view of an exemplary electronic device that may include an optical touch sensor is shown. Figure 2In the example, device 10 includes a display, such as display 14 mounted in housing 22. Display 14 may be a liquid crystal display, a light-emitting diode display such as an organic light-emitting diode display, or a display formed from a crystalline semiconductor light-emitting diode die, or other suitable display. Display 14 may have an image pixel array that extends across some or all of the front surface F of device 10 and / or other external device surfaces. The image pixel array may be rectangular or may have other suitable shapes. Display 14 may be protected using a display overlay (e.g., a transparent front housing layer) such as transparent glass or light-transmitting plastic, a sapphire layer, or other light-transmitting layer. The display overlay may overlap with the image pixel array.

[0029] The housing 22, sometimes referred to as an encapsulation or enclosure, is formed of plastic, glass, ceramic, fiber composite material, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or any combination of two or more of these materials. Figure 3 As shown in the cross-sectional side view of device 10, housing 22 and display 14 separate internal regions of device 10 (such as internal region 30) from external regions surrounding device 10 (such as external region 32). Housing 22 may be formed in a monolithic configuration, in which a portion or all of housing 22 is machined or molded into a single structure, or it may be formed using multiple structures (e.g., internal frame structures, one or more structures forming the surface of the external housing, etc.). If desired, strips may be attached to the main portion of housing 22 (e.g., in a configuration where device 10 is a watch or head-mounted device). Internal electrical components 36 (e.g., integrated circuits, discrete components, etc.) for forming control circuitry 16 and input / output devices 12 may be mounted within the interior 30 of housing 22 (e.g., on one or more substrates such as printed circuitry 38). In some configurations, components 36 may be attached to display 14 (e.g., circuitry may be mounted to the surface of display 14). In order to obtain touch input from a user’s finger or other external object (see, for example, user finger 34), the display 14 may include a touch sensor, such as an optical touch sensor (e.g., a two-dimensional optical touch sensor that collects information about the XY position of the object when the user’s finger or other external object touches the surface of the display 14).

[0030] Display 14 may include a display panel such as display panel 14P, which contains pixels P covered by display overlay 14CG. The pixels of display 14 may cover the entire front surface of device 10, or display 14 may have pixelless areas (e.g., notches, rectangular islands, inactive boundary areas, or other areas) that do not contain any pixels. Pixelless areas may be used to accommodate speaker openings and windows for optical components, such as image sensors, ambient light sensors, optical proximity sensors, 3D image sensors (e.g., structured light 3D image sensors), camera flashes, illuminators for infrared image sensors, illuminators for 3D sensors (e.g., structured light sensors), time-of-flight sensors, lidar sensors, etc.

[0031] Figure 4 This is a top view of the array of exemplary pixels P in the display panel (monitor) 14P. (Example) Figure 4 As shown, pixel P may include image pixels (such as pixel P-1) for presenting images to the user of device 10. The image pixels in display 14 may include, for example, a rectangular array of red, green and blue light-emitting diodes or backlit red, green and blue liquid crystal display pixels for presenting color images to the user.

[0032] Pixel P may also include optical touch sensor pixels, such as pixel P-2. Optical touch sensor pixels may include pixels used as light detectors and / or light emitters. A light detector can be used to detect emitted light reflected from a user's finger on the surface of display 14, thereby determining the position of the user's finger. If desired, diodes or other components can be used to form pixels that can operate as both image pixels and touch sensor pixels. When used as a touch sensor pixel, an image pixel can be configured to emit optical touch sensor illumination and / or detect optical touch sensor light. For example, a display emitter can be used to generate image light for the display, while also generating optical touch sensor illumination, and / or simultaneously serving as a photodetector for the optical touch sensor.

[0033] Image pixels, such as pixel P-1 and / or optical touch sensor pixel P-2, can have any suitable spacing. For example, image pixels can have a density sufficient to display a high-quality image to the user (e.g., 200-300 pixels per inch or more, as an example), while optical touch sensor pixels can have a lower density (e.g., less than 200 pixels per inch, less than 50 pixels per inch, less than 20 pixels per inch, etc., if desired).

[0034] Image pixels emit visible light for the user to view. For example, in a color display, image pixels can emit different colors of light, such as red, green, and blue, allowing the display 14 to display a color image. Optical touch sensor pixels can emit and / or detect visible light and / or infrared light (and / or, if necessary, ultraviolet light).

[0035] In some configurations, the light used to illuminate the user's finger in the optical touch sensor travels directly from the inner surface to the outer surface of the display cover layer 14CG, passing directly through the thickness of the display cover layer. The optical touch sensor, in which the light illuminating the user's finger propagates outward from a light source such as a light-emitting pixel in the display panel 14P, passes directly through the thickness of the display cover layer 14CG, and is then backscattered in the opposite (inward) direction to the photodetector of the optical touch sensor, is sometimes referred to herein as a direct-illumination optical touch sensor.

[0036] In other configurations, the light for the optical touch sensor can be provided using edge-coupled light-emitting diodes (LEDs) or other light sources that emit light onto the edge surface of the display overlay layer 14P, where the light is then guided within layer 14CG according to the principle of total internal reflection. For example, the LEDs can emit light into the right edge of the display overlay layer 14CG, which is then guided from the right edge to the opposite left edge of the display overlay layer 14CG within a light guide formed by the display overlay layer 14CG. In this way, light can be guided laterally across layer 14CG in the absence of contact from a user's finger. When a user's finger touches the surface of layer 14CG, total internal reflection can be locally eliminated. This local suppression of total internal reflection scatters the light inward toward the photodetector of the optical touch sensor. Optical touch sensors based on locally eliminated total internal reflection are sometimes referred to herein as total internal reflection optical touch sensors. If needed, objects other than the user's finger (e.g., computer styluses, gloves, and / or other external objects with appropriate optical properties) can also be locally deflected, thus allowing the optical touch sensor to operate in a wide range of operating environments.

[0037] The light-emitting pixels P and light-detecting pixels P in the display panel 14P can be formed using shared structures and / or separate structures. These structures may be located in the same plane (e.g., as part of a single pixel layer on a single substrate) and / or may include components located in multiple planes (e.g., in an arrangement where some components are formed in a given layer and other components are formed in one or more additional layers above and / or below the given layer).

[0038] As an example, consider an optical touch sensor comprising an array of photodetectors formed by reverse-biased diodes. These diodes may be dedicated photodetectors or light-emitting elements that function as light detectors when reverse-biased and as light sources when forward-biased. The light source in the optical touch sensor may include a visible light source (e.g., a visible light source dedicated to the optical touch sensor or also used as an image pixel) and / or may include an infrared light source. The light-emitting pixels for the optical touch sensor may be formed by light-emitting diodes (e.g., dedicated light-emitting diodes or diodes that function as light-emitting diodes when forward-biased and as photodetectors when reverse-biased). The light-emitting pixels may also be formed by pixels P that are backlit with light from a backlight unit to form backlit pixels (e.g., backlit liquid crystal display pixels). Generally, any type of photodetector signal processing circuitry can be used to detect when the photodetector has received light. For example, the photodetector may be configured to operate in photoresistor mode, wherein the photodetector changes resistance when exposed to light, and the corresponding photodetector signal processing circuitry may be used to measure the change in the resistance of the photodetector. As another example, a photodetector can be configured to operate in photovoltaic mode, where a voltage is generated when light is sensed, and the voltage signal output from the photodetector can be detected using corresponding photodetector signal processing circuitry. Semiconductor photodetectors can be implemented using phototransistors or photodiodes. Other types of photosensitive components can be used if desired.

[0039] Figure 5 It is a cross-sectional side view of an exemplary display having an array of pixels P without backlighting. Figure 5 The pixel P may include a light-emitting diode (e.g., an organic light-emitting diode, such as a thin-film organic light-emitting diode and / or a light-emitting diode formed from a crystalline semiconductor light-emitting diode die). During operation, the image pixel formed by the light-emitting diode can present an image on the display 14 that is visible to a user (such as viewer 40) viewing the display 14 along direction 42.

[0040] Figure 6 This is a cross-sectional side view of an exemplary display having an array of pixels P backlit using a backlight illumination unit 44. The backlight unit 44 may include one or more light-emitting diode strips that emit light into a backlight unit light guide layer (e.g., a transparent optical film with a light scattering structure). When the emitted light propagates through the light guide layer, the scattered light serves as backlight illumination for the pixels P (e.g., liquid crystal display pixels). In another exemplary configuration, the backlight unit 44 is a direct-illumination backlight unit that includes an array of backlight light-emitting diodes (e.g., an array-type backlight unit supporting local dimming).

[0041] Figure 7 This is a cross-sectional side view of an exemplary display with a direct-illumination optical touch sensor. (See image.) Figure 7 As shown, a visible and / or infrared light source associated with the display panel 14P emits illumination 46, which travels directly through the display overlay 14CG from its inner surface to its outer surface, thereby illuminating an external object, such as a finger 34, that touches the surface of the display 14. This produces localized backscattered light 48 that propagates in an inward (-Z) direction and is detected by a photodetector associated with the display panel 14P directly below the finger 34. In this way, an optical touch sensor can determine the lateral position (XY position) of the finger 34.

[0042] Figure 8 This is a cross-sectional side view of an exemplary display with a total internal reflection optical touch sensor. For example... Figure 8 As shown, the display 14 may include a display cover layer 14CG and a display panel 14P. Image pixels in the panel 14P can display an image that can be viewed by a viewer through the display cover layer 14CG. The outermost surface of the display panel 14P may be separated from the innermost surface of the display cover layer 14CG by a layer 50. The layer 50 may be formed of air, liquid, polymer (e.g., polymer adhesives such as optically clear adhesives, pressure-sensitive adhesives, other polymeric materials, etc.), glass, other materials, and / or combinations of these materials. Light 46 may be coupled into the layer 14CG through the sidewalls of the layer 14CG (e.g., in...). Figure 8 In the example, at the right edge surface of the outer periphery of the display overlay 14CG).

[0043] Any suitable optical coupling structure can be used to guide light 46 into the display overlay 14CG. Figure 8 In the example, light 46 is emitted by a light source such as light source 52. Light source 52 can be a light-emitting diode, such as a visible or infrared light-emitting diode or a visible or infrared laser diode. Collimator 54 can be used to collimate the emitted light from light source 52 (e.g., to form a beam with parallel rays). Prisms such as prism 56 or other optical couplers can be coupled between collimator 54 and display cover layer 14CG. Prism 56 can be mounted, for example, to the edge of display cover layer 14CG to help guide light into the edge of display cover layer 14CG. During operation, optical coupling structures such as collimator 54 and prisms or other optical couplers can be used to couple light 46 emitted from light source 52 into the interior of display cover layer 14CG in a beam oriented at a desired angle relative to the surface of layer 14CG (e.g., oriented at angle A relative to the surface normal n of display cover layer 14CG). At this angle A, light 46 will propagate within layer 14CG according to the principle of total internal reflection, unless total internal reflection is locally eliminated by the presence of fingers 34 on the outer surface of layer 14CG.

[0044] Angle A is chosen (and the materials used for layers 14CG and 50 are chosen) such that light 46 will be reflected from the innermost surface of layer 14CG according to the principle of total internal reflection. As an example, layer 14CG may have a refractive index n1 (e.g., 1.5 for glass or 1.76 for sapphire), while layer 50 may have a refractive index n2 less than n1 (e.g., less than 1.5 when layer 14CG is glass, or less than 1.76 when layer 14CG is sapphire). The difference in refractive index between n1 and n2 may be at least 0.05, at least 0.1, at least 0.2, or other suitable values.

[0045] Angle A is also chosen such that light 46 will be reflected from the uppermost surface of layer 14CG according to the principle of total internal reflection (in the absence of finger 34). In some environments, device 10 will be immersed in water 60 or otherwise exposed to moisture (raindrops, sweat, fresh or salt water surrounding device 10, etc., when the user is swimming). Angle A is preferably chosen to ensure that the presence of water 60 will not eliminate total internal reflection, while ensuring that the presence of finger 34 will locally eliminate total internal reflection, thereby generating locally scattered light 48 for detection by a photodetector near the optical touch sensor. This allows the total internal reflection optical touch sensor to operate regardless of whether some or all of the surface of display 14 is immersed in water or otherwise exposed to moisture.

[0046] As an example, consider a first exemplary scenario where layer 14CG is formed of a material with a refractive index of 1.5 (e.g., glass). The finger 34 may have a refractive index of 1.55. The water 60 may have a refractive index of 1.33. Layer 50 may have a refractive index less than 1.5. In this first scenario, total internal reflection of the upper surface of layer 14CG in the presence of water 60 is ensured by selecting a material with a refractive index greater than that of water for layer 14CG and by selecting an angle A greater than the critical angle of the upper surface of layer 14CG (in this example, greater than 62.46°, which is the critical angle associated with total internal reflection at the glass / water interface). To ensure total internal reflection at the lower surface of layer 14CG, the selected value of A should be greater than the critical angle associated with the lower interface. As an example, if layer 50 is formed of a material with a refractive index of 1.33 (the same as water) or less, the critical angle associated with the lower interface would be at least 62.46°, therefore A should be greater than 62.46°. On the other hand, if layer 50 is formed of a material with a refractive index between 1.33 and 1.5, the critical angle at the lower interface will increase accordingly, and angle A should be increased sufficiently to ensure total internal reflection at the lower interface. Regardless of the value chosen for angle A, total internal reflection will be supported at both the lower and upper surfaces of layer 14CG as long as finger 34 is not present (whether layer 14CG is in air or immersed in water). Because the refractive index of finger 34 (1.55) is greater than that of layer 14CG (1.5 in this first scenario), total internal reflection will be eliminated at finger 34 whenever finger 34 appears on the upper surface of layer 14CG, resulting in scattered light 48 that can be detected by the photodetector of the total internal reflection optical touch sensor associated with display 14.

[0047] The refractive index of layer 14CG does not need to be less than that of finger 34. As an example, consider a second exemplary scenario where layer 14CG is formed of a crystalline material such as sapphire with a refractive index of 1.76. In this second scenario, angle A should be chosen to be: 1) high enough to ensure total internal reflection at the upper (and lower) surfaces of layer 14CG in the absence of finger 34 (even in the presence of water 60), and 2) low enough to ensure that total internal reflection at the upper surface is locally eliminated when finger 34 touches the upper surface to provide tactile input. Total internal reflection at the upper surface can be ensured by choosing a value of A greater than the critical angle associated with the sapphire / water interface (e.g., the value of angle A should be greater than arcsin(1.33 / 1.76), which is 49.08°). Total internal reflection at the lower interface can be ensured by selecting a material with a refractive index of 1.33 or less for layer 50 (in which case A can still be greater than 49.08°) or by selecting a material with a greater refractive index (but still less than 1.55) for layer 50 and adjusting the value of A upward accordingly. To ensure that total internal reflection at the upper surface can be locally eliminated by finger 34, the value of angle A should be less than the critical angle associated with the sapphire / finger interface (e.g., less than arcsin(1.55 / 1.76), which is 61.72°). Therefore, when the refractive index of layer 14CG is greater than that of finger 34, there will be a range of acceptable values ​​for A defined by a lower limit (e.g., 49.08° in this example) and an upper limit (e.g., 61.72° in this example).

[0048] In the display 14 (e.g., in the display panel 14P), image pixels (e.g., red, blue, and green pixels in a color display) and / or optical touch sensor pixels (e.g., light emitters and / or detectors for implementing direct illumination and / or total internal reflection optical touch sensors) for displaying images to the user can be implemented using one or more layers of pixels, such as Figure 9 , Figure 10 and Figure 11 The exemplary display is shown in a cross-sectional side view. Figure 9 This is an exemplary arrangement of a display panel 14P with a single layer of pixels P. Figure 10 In the display panel 14P, two layers of pixels P are used. Figure 11 The diagram illustrates how the display panel 14P can have three or more layers of pixels P when needed. Generally, optical touch sensor pixels may be located in the same layer as the image sensor pixels and / or in a layer above or below the image sensor pixels.

[0049] Figure 9 , Figure 10 and Figure 11Pixel P may include image pixels and / or optical touch sensor pixels. In some arrangements, pixel P may include backlight pixels that provide backlight illumination in a local dimming backlight unit. Pixels P in different layers may have the same or different spacing. As an example, more image pixels may exist per inch compared to optical touch sensor pixels. Thin-film structures and / or discrete devices may be used when forming pixel P. In some embodiments of the display panel 14P (e.g., a display with a total internal reflection optical touch sensor), in addition to using the light source in pixel P or instead of using the light source in pixel P, the light source for the optical touch sensor may be configured to provide edge illumination (e.g., see [link to relevant documentation]). Figure 8 (Light source 52).

[0050] Figure 12 It is a cross-sectional side view of an exemplary display panel having a thin-film optical structure for forming pixels P. Figure 12 The pixels P of the display panel 14P can be thin-film diodes (e.g., organic light-emitting diodes and / or thin-film organic photodetectors or other thin-film photodetectors formed by reverse-biased thin-film diodes). For example... Figure 12 As shown, panel 14P may have a substrate 62. Substrate 62 may be formed of glass, polymer, and / or other materials. One or more material layers, such as thin film layer 64, may be formed on substrate 62. Layer 64 may include a buffer layer, dielectric and metal trace layers for forming interconnect stacks, thin film semiconductor layers for diodes, thin film transistors, capacitors, and other thin film circuits, organic layers (e.g., organic emitter layers), encapsulation layers (e.g., encapsulation layers formed of silicon oxide, silicon nitride, other inorganic dielectric materials, and / or organic dielectric encapsulation materials), and / or other layers. Figure 12 In the example, layer 64 includes a patterned layer (e.g., a patterned metal layer) forming an anode 66, an organic layer 68 such as an emitting layer for light-emitting diodes, a patterned pixel defining layer 70 (e.g., a dark polymer layer having openings for corresponding anodes 66 of diodes, each of which also has opposing overlapping transparent cathodes, such as a global cathode overlapping layers 70 and 68), and an encapsulation layer 72. If desired, other thin-film circuitry may be formed on a substrate such as substrate 62 to form a display panel structure (e.g., one or more pixel P layers for panel 14P).

[0051] Figure 13 This is a cross-sectional side view of an exemplary display panel having a crystal semiconductor die 74 on a substrate 62. The die 74 may include visible and / or infrared light-emitting diodes and / or photodetectors (e.g., diodes that can be reverse biased) for pixels P. Figure 13 The substrate 62 may be a flexible or rigid polymer layer forming a flexible or rigid printed circuit, or may be formed from other substrate materials.

[0052] Figure 12 and Figure 13 The display panel 14P is illustrative. Generally speaking, it can be used... Figure 12 The types shown (e.g., one or more thin-film panels and / or one or more panels of a die mounted on a printed circuit) and / or Figure 13 One or more display panel structures of the type shown (e.g., stacked panels) are used to form one or more pixel P layers. To help ensure sufficient transparency when pixel layers overlap, the upper layer of the pixel may have a transparent area. For example, in which… Figure 12 When pixel P overlaps with the infrared light source of the touch sensor, anode 66 can be configured to be sufficiently transparent to infrared wavelengths to allow infrared light from the infrared light source to pass through anode 66. In this type of arrangement, Figure 12 Pixel P in the image can be an image pixel that emits visible light. Infrared light sources and detectors (e.g., using...) Figure 13 The source and detector formed by diode 74 can be located below the image pixels (as an example). The transparency of the upper layer of the display having stacked pixel P layers can also be achieved by forming layers such as layer 70 from transparent materials. Figure 12 Other layers 64 and / or such as Figure 13 The substrate 62 layer is provided by forming holes in the substrate layer, pixel defining layer and / or other display layers, by selectively omitting some or all of the anodes or other structures in the anodes of certain pixels P to create transparent window areas in the pixel layer, etc.

[0053] Such as combination Figure 8 As described, one or more light-emitting diodes or other light sources, such as light source 52 (together with an optical coupler), can be used in a total internal reflection optical touch sensor to emit a light beam 46 at a desired angle A into the display overlay layer 14CG. If desired, one or more overlapping light sources 52 (e.g., an array of infrared and / or visible light sources, such as light-emitting diodes and / or laser diodes, located below the image pixel array in panel 14P) can be used to couple light 46 into layer 14CG for total internal reflection. Figure 14 As shown, for example, display panel 14P may have an array of light sources 52, each of which emits light 46' in a vertically oriented cone. Refractive index matching structures such as layer 78 may have a refractive index value equal to or close to that of layer 14CG to help couple light emitted from each source 52 into layer 14CG and / or may include gratings or other light coupling structures. If desired, the lowermost surface of layer 78 may be angled relative to the surface normal n of layer 14CG (e.g., to form a prism) and / or may contact the source 52 to help receive light 46' from the source 52 without undesirable reflections. Figure 14The configuration is illustrative. A mask 76 may be formed on layer 78. The mask 76 may have an annular opening 80 or other openings that restrict the angular orientation of light 46' as it passes through the mask 76 and layer 78 into layer 14CG. In this way, the light from source 52 is characterized by the ray 46 in layer 14CG being oriented at a desired angle A relative to the surface normal n, to support total internal reflection in layer 14CG in the absence of finger 34. Light sources such as... Figure 14 The light source 52 can be a pixel P located in, above, and / or below an image pixel in panel 14P. If necessary, the light source may be such as... Figure 14 The light source 52 can be formed by multiple light sources (e.g., light sources stacked on top of each other or mounted side-by-side on a shared substrate). In this type of arrangement, each of the multiple light sources can be optimized for a specific function. For example, one light source can be configured to generate display illumination, and another light source can be configured to generate collimated total internal reflection illumination for an optical touch sensor.

[0054] It may be desirable to limit the reception angle associated with a given light-detecting pixel. For example, it may be desirable to provide a photodetector pixel with an angle filter in an optical touch sensor, the angle filter causing the photodetector pixel to respond primarily or exclusively to scattered light rays perpendicular to the surface normal n of layer 14CG (e.g., light rays traveling directly inward from layer 14CG after being scattered from the user's finger 34). In this way, the effects of noise from stray light can be reduced.

[0055] An angle-receiving filter can be used to achieve increased sensitivity to light oriented at a desired angle. As an example, consider... Figure 15 The arrangement. For example... Figure 15 As shown, the angle filter 82 can be formed from a mask 88 on the transparent layer 84. An optional lens, such as lens 86, can overlap and align with the opening 90 in the mask 88. The mask 88 can be formed from black ink, metal, or other opaque masking material. The opening 90 can be a circular hole or other gap in the opaque layer of the mask 88. The transparent layer 84 can be one of the layers in the panel 14P, such as an encapsulation layer or other transparent dielectric layer.

[0056] exist Figure 15 In this configuration, only scattered rays 48 propagating perpendicular to layer 14CG (e.g., parallel to the surface normal n of layer 14CG) will pass through opening 90 after passing through lens 86. Off-axis rays, such as Figure 15 The off-axis scattered light rays 48' will be blocked by the mask 88. The light-detecting pixels for the optical touch sensor can be aligned with the opening 90 and located below the opening 90, so that coaxial light can be detected.

[0057] If needed, filters such as filter 82 can be configured to allow only off-axis light at the desired angle to pass through (e.g., see [reference]). Figure 16 The filter 82 allows only off-axis rays 48” to pass through to the overlapping photodetector due to a lateral offset D between the center of lens 86 and the center of opening 90. Off-axis filters, such as Figure 16 The filter 82 can be used in the panel 14P, on the edge surface of the layer 14CG, and / or in other locations in the device 10 associated with the optical touch sensor (e.g., to help improve detection sensitivity by collecting only light associated with finger-scattered light, guide light, etc. at a specific angle).

[0058] Masks such as Figure 15 and Figure 16 The mask 88 can be formed on any suitable transparent layer 84. Figure 17 In the example, a single mask layer is used to form mask 88, and this single mask layer is located on the top surface of transparent layer 84. Figure 18 In the example, mask 88 has a first mask layer and a second mask layer 88' on opposite upper and lower surfaces of layer 84 (e.g., encapsulation layer or other transparent display layer). Figure 19 This illustrates how a mask 88 can be formed from a via aperture in a relatively thick display layer (e.g., a pixel-defining layer or other opaque display layer). Figure 19 In this configuration, the width W of the opening 90 is less than the thickness T of the opaque layer forming the mask 88. Masks such as... Figure 17 , Figure 18 and Figure 19 The mask may or may not be used with one or more lenses, such as lens 86. An angle filter formed using lens 86 and / or mask 88 may each overlap and align with a corresponding photodetector (e.g., a pixel P with a photodetector), or may otherwise be used to help limit the angular acceptability of the photodetector in an optical touch sensor.

[0059] The optical touch sensor measurement results can be collected during the period when the image light is not output from the display 14, or during the period when the image light is displayed.

[0060] As a first example, consider Figure 20 The arrangement is of the type shown in the sequence diagram. Figure 20In this configuration, time period P1 corresponds to the time period during which image pixels are outputting light for an image being viewed by the user, and time period P2 is the time period during which light-detecting pixels for the optical touch sensor are collecting sensor measurements. In one exemplary arrangement, all image pixels in the display 14 emit light only during time period P1 (e.g., image frames), and all light-detecting pixels in the display 14 acquire sensor measurements only during time period P2 between time periods P1 to detect scattered light from the finger 34. In this type of operation, a light source separate from the image pixels in the display 14 is used to provide illumination for the optical touch sensor. In another exemplary arrangement, the image output operation of time period P1 and the light-sensing operation of time period P2 may overlap. When the optical touch sensor illumination is generated by image pixels, the optical touch sensor can use knowledge of image pixel modulation and / or the intensity of the image pixel output at each location on the display 14 to help analyze the detected scattered light. When the optical touch sensor illumination is provided from a light source that generates total internal reflection light in the display overlay 14CG, both optical touch sensor light and image pixel light from the light source can be generated during time period P2.

[0061] like Figure 21 As shown, an image (e.g., an image frame) can be output during time period P1, while optical touch sensor measurements are obtained during the overlapping time period P2. As an example, the light used to illuminate finger 34 can be generated by image pixels during time period P2, or it can be generated by a separate light source (e.g., an infrared LED or other infrared-emitting pixel separate from the image pixels of display 14) during time period P2. Photosensitive pixels (e.g., infrared photosensitive pixels or visible photosensitive pixels) can collect scattered light measurements during time period P2. In some arrangements (e.g., when infrared light is being used for optical touch sensing), the photosensitive pixels may have optical filters that block visible light and allow infrared light to pass through to reduce potential visible light interference from image pixels. In configurations where visible light is used to illuminate finger 34, image frame information about which image pixels are active across display 14 can be used to determine how much visible light is expected to be scattered by finger 34 at a given location on display 14.

[0062] Signal modulation techniques (e.g., modulating emitted light over time at a predetermined frequency in a known mode and demodulating sensed light accordingly) can be used to help extract optical touch sensor signals from detected ambient light signals and / or measured signals associated with stray image light. For example, emitted light can be modulated at a specific frequency and detected light signals can be demodulated (synchronously) at the same frequency. In this way, external optical interference from ambient light sources and internal optical interference (e.g., interference from stray display light, which may occur during the sensing period in some embodiments) can be blocked.

[0063] like Figure 22 As shown in the example, the display panel 14P may include pixels P, each of which includes a corresponding diode 92. Pixel P may use the diode 92 as a light source. For example, the diode 92 may be forward biased to serve as an image pixel emitting visible light to form an image for the user. The emitted light 46 from the diode 92 may also be used as illumination for an optical touch sensor (e.g., in the presence of a finger 34 on the display 14, the light 46 may be backscattered to form backscattered light 48). The diode 92 may be a light-emitting diode (thin-film organic light-emitting diode or crystal semiconductor die) or a laser diode. In some configurations, the diode 92 may be configured to emit infrared light. In a total internal reflection optical touch sensor arrangement, if desired, it can be combined with... Figure 8 The description describes providing edge lighting to the display overlay 14CG to provide illumination for the finger 34.

[0064] Some or all of the diodes in diode 92 can be reverse biased to function as photodetectors for an optical touch sensor. As an example, the photodiodes can extend in an array across display 14, allowing the photodiodes to measure and thereby determine the position of backscattered light 48 from finger 34.

[0065] The diode 92, used as a photodetector in an optical touch sensor, can be uniquely used as a photodetector for the optical touch sensor, or it can sometimes be forward biased to emit light for image and / or optical touch sensor illumination, and sometimes reverse biased to function as a photodetector for the optical touch sensor. As an example, the photodetector diode 92 can sometimes emit visible image light (e.g., when used as an image pixel), and sometimes detect backscattered light 48 (e.g., see pixel P', where the diode 92 is configured to both emit light 46 and detect light 48). In arrangements where the diode 92 can function as both a light emitter and a photodetector, the use of additional optical components (e.g., additional light-emitting devices and / or light sensors) to form the optical touch sensor can be reduced or eliminated.

[0066] If needed, additional components for the optical touch sensor pixels can be formed above or below the pixel array. As an example, consider... Figure 23 A cross-sectional side view of the display panel 14P. Figure 23 In the example, pixel P is formed in a single layer (e.g., as combined with...). Figure 12 The pixel P describes a thin-film pixel layer on a flexible or rigid display panel substrate, or a layer such as a composite pixel. Figure 13 The pixel P is described in the crystalline semiconductor die layer that forms the pixel. In the exemplary configuration, Figure 23The pixels P” in the display panel 14P form an image pixel layer that emits visible light to generate an image viewed by a user of the device 10. Alternatively, the pixel P” may have a diode that can be reverse-biased to form a photodetector for an optical touch sensor and / or have an infrared diode for providing illumination for the optical touch sensor.

[0067] like Figure 23 As shown, optical component 94 may be located above and / or below pixel P". Optical component 94 may be based on a diode (e.g., a light-emitting diode such as a light-emitting diode and a laser diode, a light-detecting diode such as a photodiode, and / or a diode that can be forward-biased to emit light and reverse-biased to detect light). The diode and / or other structure forming component 94 may be a thin-film diode (e.g., an organic light-emitting diode, an organic thin-film diode used as a photodetector, etc.) and / or may be formed from a crystalline semiconductor die. Component 94 may be mounted on one or more substrates such as Figure 13 On the substrate 62, it can be mounted on a shared substrate having a pixel P” structure, and / or can be otherwise incorporated into the display panel 14P.

[0068] In some configurations, the light-emitting component 94 may be located above pixel P”, and the light-detecting component 94 may be located below pixel P”. In other configurations, the light-emitting component 94 may be located below pixel P”, and the corresponding light-detecting component for the optical touch sensor may be located above pixel P”. An arrangement in which some of the light-emitting components 94 are mounted above and below pixel P” and / or some of the light-sensitive components 94 are mounted above and below pixel P” may also be used. Pixel P” and / or component 94 may operate using visible light and / or infrared light.

[0069] In an arrangement where the optical touch sensor component 94 is formed above the pixel P”, the substrate on which the component 94 is mounted is transparent to light emitted and / or detected by the pixel P”. In an arrangement where the optical touch sensor component 94 is formed below the pixel P”, the anode of the pixel P”, the pixel defining layer for forming the pixel P”, and / or other structures forming the pixel array of the pixel P” are sufficiently transparent (by using materials that allow infrared and / or visible light to pass through, by forming openings, etc.) to allow the component 94 to operate through the pixel P” layer. As an example, the pixel P” may be included in a thin-film organic light-emitting diode display panel, the pixels having an anode that is sufficiently transparent to allow infrared light for the optical touch sensor to pass through, and the component 94 may include an infrared light-emitting diode die and an infrared photodetector die mounted on a substrate layer located below the pixel P”. In a total internal reflection optical touch sensor, light for the optical touch sensor (e.g., infrared or visible light) may be emitted into the display overlay layer 14CG, and the backscattered light 48 may be detected by a photodetector (e.g., the photosensitive component 94 above and / or below the pixel P”).

[0070] If needed, backlit pixels can be used to form an optical touch sensor. As an example, consider... Figure 24 The display panel 14P. In this example, liquid crystal display pixels in the liquid crystal display panel can be used to form an array of image pixels P. The backlight unit 98 can emit backlight illumination through the liquid crystal display panel formed by the pixels P. The backlight unit 98 may have a backlight pixel BP array, which can be locally dimmed to enhance image contrast (e.g., the backlight unit 98 may be a direct illumination backlight unit that supports local dimming). The backlight pixels BP may include optical components 96. Components 96 may include white backlight pixels or other backlight pixels that generate backlight illumination for the pixels P. Components 96 may also include a (visible and / or infrared) light source and / or a (visible and / or infrared) light detector for forming an optical touch sensor. As an example, each backlight pixel BP may have a backlight illumination component such as a light-emitting diode that emits backlight illumination (e.g., white backlight illumination), may have an infrared light source (e.g., an infrared light-emitting diode or an infrared laser), and may each have an infrared light detector (e.g., an infrared photodetector). In this type of arrangement, the infrared light source and detector can be mounted on a common substrate together with the backlight illumination LED, and / or on another substrate (above and / or below the backlight illumination LED). An arrangement in which visible light from the backlight illumination LED (e.g., light 46 illuminating a user's finger to generate backscattered light 48) can also be used to generate illumination for the optical touch sensor.

[0071] Although touch sensor operation is sometimes described in the context of an arrangement in which light propagates primarily at a single angle within the display overlay 14CG occurs, the light source can emit light into the display overlay 14CG at multiple different angles (e.g., angle A1 and different angles A2). In this type of arrangement, a first object having a first refractive index nfirst can locally eliminate total internal reflection of light at angle A1 without locally eliminating total internal reflection of light at angle A2, while a second object having a second refractive index nsecond, greater than the first refractive index, can locally eliminate total internal reflection of light at both angle A1 and angle A2. Because the first and second objects interact differently with the optical touch sensor, the touch sensor can distinguish between the first and second objects. This allows the device 10 to respond differently to input from different types of objects. As an example, in a drawing application, when the first object moves across the layer 14CG, a line can be drawn with a first thickness, while when the second object moves across the layer 14CG, a line can be drawn with a second thickness. The first and second objects can be any suitable object (one or more different types of styluses, fingers, and / or other objects). If needed, light at each angle can be associated with a different corresponding color, and a dedicated array of detectors (each detector responding to a different color) can be used.

[0072] According to one embodiment, an electronic device configured to collect touch input from a finger is provided, the electronic device comprising: a display having a display cover with a surface; and an optical touch sensor having a light source and photodetectors, the light source being configured to emit light into the display cover, the light being guided within the display cover by total internal reflection when the surface of the display cover is immersed in water, and the total internal reflection being partially eliminated to scatter the light toward the photodetectors when the finger touches the surface.

[0073] According to another embodiment, the photodetector is arranged in an array that extends across the display.

[0074] According to another embodiment, the display has an array of light-emitting diodes configured to display images.

[0075] According to another embodiment, the light source is composed of an array of light-emitting diodes superimposed on each other.

[0076] According to another embodiment, the display overlay has an edge surface, and the light source is configured to emit light into the edge.

[0077] According to another embodiment, the light source has a light-emitting diode, a collimator, and an optical coupler coupled between the collimator and the edge surface.

[0078] According to another embodiment, the display has a liquid crystal display pixel array.

[0079] According to another embodiment, the finger has a first refractive index, and the display overlay has a second refractive index that is less than the first refractive index.

[0080] According to another embodiment, the display cover layer includes glass.

[0081] According to another embodiment, the finger has a first refractive index, and the display overlay has a second refractive index greater than the first refractive index.

[0082] According to another embodiment, the display overlay includes sapphire.

[0083] According to another embodiment, the surface has a surface normal, and the light source is configured to emit light at an angle relative to the surface normal into the edge surface of the display overlay, wherein the angle has a value between 49.08° and 61.72°.

[0084] According to another embodiment, the light source has a light-emitting diode, a collimator, and an optical coupling structure coupled between the collimator and the edge surface.

[0085] According to another embodiment, the light-emitting diode includes an infrared light-emitting diode.

[0086] According to another embodiment, the light-emitting diode includes a visible light-emitting diode.

[0087] According to another embodiment, the light source includes an infrared light source, the emitted light includes infrared light, the display includes an array of organic light-emitting diode pixels with anodes that transmit at least some of the infrared light when the infrared light is scattered by the finger toward the photodetectors, and the photodetectors include an infrared photodetector layer superimposed by the organic light-emitting diode pixel array.

[0088] According to another embodiment, the light source is configured to modulate the emitted light, and the photodetector is configured to demodulate the scattered light synchronously.

[0089] According to one embodiment, an electronic device configured to collect touch input from an external object is provided, the electronic device comprising: a housing; a display coupled to the housing; and an optical touch sensor configured to collect touch input from the external object when the external object is touching a surface of the display, the optical touch sensor including a light sensor array configured to measure light scattered from the external object when the display is exposed to water and the external object is touching the surface of the display.

[0090] According to another embodiment, the display includes a display overlay, and the optical touch sensor includes a light source coupled to the edge of the display overlay.

[0091] According to another embodiment, the display has image pixels configured to emit image light, and these light sensors are separate from these image pixels and do not emit light.

[0092] According to another embodiment, the display has an array of diodes configured to emit image light, and at least some of these diodes serve as light sensors.

[0093] According to one embodiment, a touch-sensitive display is provided configured to collect touch input associated with finger contact, the touch-sensitive display comprising: an image pixel array configured to display an image; a display overlay overlapping the image pixel array; an array of light sensors; and an optical touch sensor light source configured to emit light into an edge surface of the display overlay, the light being guided through the display overlay by total internal reflection when the surface of the display overlay is exposed to moisture, wherein, in the case of finger contact with the display overlay, total internal reflection is locally eliminated to scatter the light toward the light sensors.

[0094] According to another embodiment, the touch-sensitive display includes a mask having an opening that overlaps with each of the light sensors to form an angle filter for the light sensor.

[0095] According to another embodiment, the touch-sensitive display includes a lens that overlaps with each opening.

[0096] According to one embodiment, a touch-sensitive display configured to collect touch input associated with finger contact includes: an image pixel array configured to display an image; a display overlay overlapping the image pixel array; an array of light sensors; each light sensor being overlapped by an angle filter; and an optical touch sensor light source configured to emit light into the display overlay, the light being guided through the display overlay by total internal reflection when the surface of the display overlay is exposed to moisture, and in the event of finger contact with the display overlay, total internal reflection is locally eliminated to scatter the light toward the light sensors.

[0097] According to another embodiment, each angle filter includes a mask with an opening, a lens overlapping the opening, and a transparent layer located between the mask and the lenses.

[0098] According to another embodiment, each angle filter includes a first mask having a first opening, a second mask having a second opening overlapping the first opening, and a transparent layer located between the first mask and the second mask.

[0099] The foregoing description is merely illustrative and various modifications can be made to the described implementation scheme. The described implementation scheme can be implemented independently or in any combination.

[0100] 10 electronic devices 12 Input-output devices 14 monitor 18 sensor 16 control circuit 22 shell P, P-1, P-2, P', P” Pixels 30 internal area F Front 36 part 32 external area 38 substrate 14P Display panel 14CG Display overlay 34 finger 40 Viewers 42 direction 44 Backlight unit 46、46’、48、48’ light 50 layer A angle 60 water n Surface normal 52 light source 54 collimator 56 Prism 70 Pixel-limited layer 66 anode 68 Organic layer 64 thin film layer 62 substrate 72 Encapsulation layer 74 semiconductor die 78 Refractive index matching layer 80 Opening 76 mask 86 lens 88、88’ mask 90 Opening 82 filter 84 transparent layer P1, P2 Time period 92 diode 94 Optical components BP Backlight unit pixels 98 Backlight unit 96 Optical components

Claims

1. An electronic device configured to collect touch input from a finger, comprising: A display having a display cover layer with a surface; as well as An optical touch sensor having a light source and a photodetector, wherein the light source is configured to emit light into the display overlay, the light being guided within the display overlay by total internal reflection when the surface of the display overlay is immersed in water, and wherein when the finger touches the surface, total internal reflection is partially eliminated to scatter the light toward the photodetector.

2. The electronic device of claim 1, wherein the photodetectors are arranged in an array extending across the display.

3. The electronic device of claim 1, wherein the display has an array of light-emitting diodes configured to display an image.

4. The electronic device of claim 3, wherein the light source is overlapped by the array of light-emitting diodes.

5. The electronic device of claim 1, wherein the display overlay has an edge surface, and wherein the light source is configured to emit light into the edge.

6. The electronic device of claim 5, wherein the light source comprises a light-emitting diode, a collimator, and an optical coupler coupled between the collimator and the edge surface.

7. The electronic device of claim 1, wherein the finger has a first refractive index, and wherein the display overlay has a second refractive index less than the first refractive index.

8. The electronic device of claim 7, wherein the display cover layer comprises glass.

9. The electronic device of claim 1, wherein the finger has a first refractive index, and wherein the display overlay has a second refractive index greater than the first refractive index.

10. The electronic device of claim 9, wherein the display overlay comprises sapphire.

11. The electronic device of claim 9, wherein the surface has a surface normal, wherein the light source is configured to emit light at an angle relative to the surface normal into an edge surface of the display overlay, and wherein the angle has a value between 49.08° and 61.72°.

12. The electronic device of claim 1, wherein the light source comprises an infrared light source, wherein the emitted light comprises infrared light, wherein the display comprises an array of organic light-emitting diode pixels having an anode, the anode transmitting at least some of the infrared light when the infrared light is scattered by the finger toward the photodetector, and wherein the photodetector comprises an infrared photodetector layer superimposed on the array of organic light-emitting diode pixels.

13. The electronic device of claim 1, wherein the light source is configured to modulate the emitted light, and wherein the photodetector is configured to synchronously demodulate the scattered light.

14. An electronic device configured to collect touch input from an external object, comprising: shell; A display, the display being coupled to the housing; as well as An optical touch sensor configured to collect touch input from an external object when the external object is touching the surface of the display, wherein the optical touch sensor includes a light sensor array configured to measure light scattered from the external object when the display is exposed to water and the external object is touching the surface of the display.

15. The electronic device of claim 14, wherein the display has an array of diodes configured to emit image light, and wherein at least some of the diodes serve as the light sensor.

16. A touch-sensitive display configured to collect touch input associated with finger contact, the touch-sensitive display comprising: An image pixel array configured to display an image; A display overlay layer that overlaps with the image pixel array; Optical sensor array; as well as An optical touch sensor light source is configured to emit light into the edge surface of the display cover layer, the light being guided through the display cover layer by total internal reflection when the surface of the display cover layer is exposed to moisture, wherein, when a finger touches the display cover layer, total internal reflection is partially eliminated to scatter the light toward the light sensor.

17. The touch sensitive display of claim 16, further comprising: A mask having openings that overlap with each of the light sensors to form an angle filter for the light sensors.

18. A touch-sensitive display configured to collect touch input associated with finger contact, the touch-sensitive display comprising: An image pixel array configured to display an image; A display overlay layer that overlaps with the image pixel array; An array of optical sensors, wherein each optical sensor is superimposed with an angle filter; as well as An optical touch sensor light source is configured to emit light into the display overlay, the light being guided through the display overlay by total internal reflection when the surface of the display overlay is exposed to moisture, wherein when the finger touches the display overlay, total internal reflection is partially eliminated to scatter the light toward the light sensor.

19. The touch-sensitive display of claim 18, wherein each angle filter comprises a mask having an opening, a lens overlapping the opening, and a transparent layer located between the mask and the lens.

20. The touch-sensitive display of claim 18, wherein each angle filter includes a first mask having a first opening, a second mask having a second opening overlapping the first opening, and a transparent layer located between the first mask and the second mask.

Images