Devices and systems for displaying below an image sensor

Abstract

The present disclosure relates to devices and systems for displaying below an image sensor. The present disclosure describes an optical system. The optical system may include a sensor that may be located in a mobile device. The optical system may use the same light source to image the display and provide light for the sensor or sensor device. The optical system may be configured so that randomly polarized light will leave the device for viewing, so that a user can view the display in any rotational orientation while wearing polarized glasses. The optical system may be further configured to reduce reflections in the mobile device from ambient light entering the system and from reflected and backscattered light, thereby mitigating cross contamination of imaging light to the display.

Description

Technical Field

[0001] Embodiments described herein relate generally to mobile devices having sensors and / or sensor arrays, and more particularly to depolarizing light for viewing purposes and allowing reflected light to reach the sensors and / or sensor arrays. Background Art

[0002] Mobile devices can be used by anyone in a variety of locations, such as inside and outside of buildings, and at different times of the day, including morning, daytime, and evening. During some time periods of the day, a user may be outdoors and view the screen of a mobile device while wearing sunglasses. Some of these sunglasses may have polarized lenses that may make it difficult to view the mobile device screen. Additionally, in some examples, a user may view the screen of a mobile device through a polarizing film, a polarizing plate, a polarizing layer, or a polarizing film on glass. In any of these examples, it may be difficult for a user to view the screen of a mobile device in various orientations. Summary of the invention

[0003] Embodiments of the systems, devices, methods, and apparatus described in the present disclosure relate to mobile devices having sensors and / or sensor arrays. The present disclosure also describes systems, devices, methods, and apparatuses relating to mobile devices that can be viewed through a polarization layer when the device is in landscape or portrait mode.

[0004] In some examples, the present disclosure describes a sensing device, which may include: a reflective element; a first optical delay element, the first optical delay element being configured to receive depolarized light along an optical path from the reflective element; a polarizing element, the polarizing element being configured to receive the light along the optical path from the first optical delay element; a second optical delay element, the second optical delay element being configured to receive the light along the optical path from the polarizing element, wherein the first optical delay element has a higher delay amount than the second optical delay element; and a sensor array, the sensor array being configured to receive the light along the optical path—configured to receive the light after the light has passed through the second optical delay element, wherein the sensor array is further configured to sense the light for determining physiological information of a user. In some examples, the first optical delay element may be configured to transmit the depolarized light along the second optical path to the reflective element, and may be configured to receive the depolarized light and reflected light along the optical path from the user's finger. In addition, in some examples, the first optical delay element may have a delay value greater than 1000 nanometers, and in some examples, may have a delay value equal to or greater than 8000 nanometers. Additionally, in some examples, the first optical delay element may be further configured to receive polarized light along a second optical path from the polarization element and transmit the randomly polarized light along the second optical path toward the reflective element.

[0005] In some examples, the sensing device may include an organic light emitting diode, which may be configured to receive light from the second optical delay element and transmit the light to the sensor array. In some examples, the polarizing element of the sensing device may be configured to absorb light at a 45 degree angle to the horizontal axis. In other examples, the reflective element may be sapphire.

[0006] In some examples, the present disclosure describes an optical system, which may include: a light emitting layer, which may be configured to emit light along a first optical path toward a polarizing layer; the polarizing layer, which is configured to polarize light and transmit the polarized light along the first optical path toward an optical depolarizing layer; and the optical depolarizing layer, which may be configured to randomly polarize the received polarized light and transmit the randomly polarized light along the first optical path toward at least a protective layer. In some examples, the optical system may include a sensor array, which may be configured to receive light along a second optical path from the optical depolarizing layer, wherein the received light may be used to determine physiological information of a user. In some examples, the optical depolarizing layer may have a retardation of at least 8000 nanometers. In some examples, the protective layer may be configured to reflect the randomly polarized light to the optical depolarizing layer, and the optical depolarizing layer may be configured to receive reflected randomly polarized light along the second optical path from a finger of the user. In other examples, the optical depolarizing layer is at least one of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

[0007] In some examples, the optical system may include an optical delay layer disposed between the light emitting layer and the polarization layer. In some examples, the polarization layer of the optical system may be configured to receive randomly polarized light along the second optical path from the optical delay layer. In other examples, the light emitting layer of the optical system may be an organic light emitting diode configured to emit light, wherein the emitted light may be used to determine physiological information of the user.

[0008] In some examples, the present disclosure describes a mobile device, which may include: a cover glass, the cover glass is disposed in an optical path; and an optical stack, the optical stack is adjacent to the cover glass and disposed in the optical path. In some examples, the optical stack may include: a first optical delay plate, the first optical delay plate may be disposed in the optical path and may be configured to randomly polarize light; a polarizer, the polarizer is disposed in the optical path; and a second optical delay plate, the second optical delay plate may be disposed in the optical path. The mobile device may also include: a display layer, the display layer is adjacent to the sensing layer and disposed in the optical path; and the sensing layer, the sensing layer may be disposed in the optical path and may be configured to sense light received in the optical path, wherein the sensing layer may be further configured to use the sensed light to determine physiological information of a user. In some examples, the first optical delay plate may be configured to receive polarized light from the polarizer and randomly polarize the received polarized light, and may have a retardation value equal to or greater than 8000 nanometers.

[0009] In addition to the illustrative aspects and embodiments described, further aspects and embodiments will become apparent by reference to the drawings and by study of the following descriptions. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure will be readily understood through the following detailed description in conjunction with the accompanying drawings, in which like reference numerals refer to like structural elements, and in which:

[0011] Figure 1A An example of a user viewing a mobile device is shown;

[0012] Figure 1B An example of a user viewing a mobile device is shown;

[0013] Figure 2 An exemplary layout of an optical system is shown;

[0014] Figure 3 An exemplary layout of an optical system is shown;

[0015] Figure 4 An example of a process flow is shown;

[0016] Figure 5 An example of a process flow is shown;

[0017] Figure 6 shows an example of a process flow; and

[0018] Figure 7 An example electrical block diagram of an electronic device is shown.

[0019] The use of cross-hatching or shading in the drawings is generally provided to clarify boundaries between adjacent elements and also to facilitate legibility of the drawings. Thus, the presence or absence of cross-hatching or shading does not express or indicate any preference or requirement for particular materials, material properties, element proportions, element sizes, commonality of similar illustrated elements, or any other characteristic, property, or attribute of any element shown in the drawings.

[0020] Furthermore, it should be understood that the proportions and sizes (relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, spacings, and positional relationships presented therebetween are provided in the accompanying drawings solely to facilitate understanding of the various embodiments described herein, and therefore may not necessarily be presented or illustrated to scale and are not intended to indicate any preference or requirement for the embodiments illustrated to exclude the embodiments described in conjunction therewith. DETAILED DESCRIPTION

[0021] CROSS-REFERENCE TO RELATED APPLICATIONS

[0022] This patent application is a non-provisional application of U.S. Provisional Patent Application No. 62 / 905,355 filed on September 24, 2019, and claims the benefit of the U.S. Provisional Patent Application No. 62 / 905,355 under 35 U.S.C. 119(e), the contents of which are incorporated herein by reference as if fully disclosed herein.

[0023] Reference will now be made specifically to the representative embodiments shown in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to a preferred embodiment. On the contrary, it is intended to cover alternatives, modifications and equivalent forms that may be included in the spirit and scope of the embodiments defined by the appended claims.

[0024] Generally speaking, people may use mobile devices in many environments. Some users may use mobile devices outdoors and may be wearing sunglasses when viewing the screen of the mobile device. In some cases, the sunglasses and the screen of the mobile device may have the same polarization. For example, both may be linearly polarized, or both may be circularly polarized. Although the user may be able to view the mobile device screen in, for example, portrait mode, once the mobile device is rotated to landscape mode due to transverse polarization, the mobile device screen may appear dark or black, and the user may have to remove their sunglasses to view the screen. Although the user can view the screen without sunglasses, it may be difficult to rotate the screen, remove the sunglasses, or otherwise easily interact with the device in some cases (such as when the user's hands are full or busy with other things).

[0025] Additionally, mobile devices may use various biometric information such as a user's fingerprint or facial recognition as a security measure. Biometric information may be used on a mobile device to unlock the device for use or to verify authentication for purchases, etc. In some examples, it may be useful to incorporate the use of biometric authentication information into a mobile device that can be viewed while wearing sunglasses or any other type of polarized glasses.

[0026] Alternatively and as discussed herein, the mobile device can implement various features by allowing the user to view the mobile device screen while wearing polarized glasses (regardless of the orientation of the mobile device screen) and by incorporating sensors into the mobile device. The user may also be able to view the mobile device screen if there is any type of linear polarizing film, linear polarizer, linear polarizing coating on glass, or any other linear polarizing element between the mobile device screen and the user viewing the screen.

[0027] The mobile device can be any type of device, including but not limited to a mobile phone, a smart phone, a watch, a tablet computer, a laptop computer, etc. In some examples, the mobile device can also be a sensing device. The sensing device can include a reflective element, an optical element, and a sensor array along an optical path. The reflective element can depolarize or randomly polarize any light reflected from the surface of the reflective element. For example, polarized light incident on the surface of the reflective element can be reflected, and the reflected light from the surface can be randomly polarized. The terms random polarization and depolarization are used interchangeably herein. In addition, randomly polarized light incident on the surface of the reflective element can be reflected as randomly polarized light. In some examples, the optical element can be configured to reduce reflections, making the content on the display of the mobile device easier to see by the user, and additionally allowing the reflected light to reach the sensor array.

[0028] In some examples, the optical element may include a first optical delay element, a polarizing element, and a second optical delay element, wherein the first optical delay element and the second optical delay element may have different delay values. In the case of including these optical elements, the mobile device may also be able to use the display light source as the light source of the sensor. In addition, the optical element may allow the user to view the mobile device screen while wearing polarized glasses, even when the mobile device screen is rotated in any orientation (e.g., from landscape to portrait (or vice versa)). In addition, the optical element may reduce optical artifacts caused by light totally internally reflected from elements of the mobile device display stack.

[0029] In some examples, light may be emitted from the light emitting layer and may pass through a first optical delay element and then through a polarizing element. The polarizing element may, for example, polarize light in a p-polarization state. The polarized light may then pass through a second optical delay element having a high delay value, for example, greater than 1000 nanometers. The second optical delay element may depolarize the received polarized light. The depolarized light may be passed to a reflective element such as a cover glass, and at least some of the depolarized light may be reflected back. In some examples, at least a portion of the depolarized light may be additionally reflected back by a user's finger. The reflected light may be at least partially reflected back toward the second optical delay element, and after passing through the second optical delay element, the light may still be depolarized. The terms random polarization and depolarization are used interchangeably herein. The randomly polarized light may then be passed to the polarizing element. Since the light is randomly polarized, it may leave the polarizing element as linearly polarized light. The polarized light may pass through the first optical delay element (thus becoming circularly polarized light), may pass through the light emitting element, and may then be received by a sensing element or sensing array. In some examples, the light received at the sensing element or sensing array may be used to determine the user's biometric data. In some examples, the reflected light can be absorbed or stopped at the polarization layer, and the image quality on the mobile device screen may be better due to the reduction of cross contamination of light emitted from the display layer and circularly polarized light reflected from the sensor array, which will be relative to 1A to Figure 3 Discussed in further detail.

[0030] Various configurations of light sources for using optical elements to enable mobile devices to use displays and sensors are described herein. In some embodiments, the optical elements can enable a user to view a mobile device screen in any orientation while wearing polarized glasses.

[0031] References below Figures 1A to 6 These and other embodiments are discussed. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these drawings is for illustrative purposes only and should not be construed as limiting.

[0032] Figure 1A and Figure 1B An example 100 of a user viewing a mobile device is shown. In some examples, the user 105 may be wearing sunglasses 110 while viewing a screen 115 of a mobile device 120. The mobile device 120 may be any type of device, including but not limited to a mobile phone, a smart phone, a watch, a tablet, a biometric monitoring or sensing device such as a heart rate monitor, a GPS device, a laptop, etc. In some examples, the mobile device may also be a sensing device with the ability to sense biometric or physiological data of the user.

[0033] like Figure 1AAs shown, user 105 may be wearing sunglasses 110 to view mobile device screen 115. In many cases, the user may rotate mobile device 120 to change the orientation of information displayed on device screen 115. For example, the user may wish to view content in landscape or portrait mode, or capture images or videos in corresponding modes. User 105 may rotate mobile device 120 from landscape to portrait mode. Figure 1A The vertical or portrait position or mode 125 shown is rotated to Figure 1B The horizontal or lateral position or mode 130 is shown and in Figure 1A and Figure 1B In both cases the user may be able to view the mobile device screen 115 .

[0034] As the mobile device is rotated, the screen 115 of the mobile device will also change orientation. In some examples, the sunglasses 110 may have linear polarizing lenses. In some examples, problems may occur when viewing a mobile device screen with a polarizing lens, the user 105 may be able to view the mobile device screen 115 when it is in a portrait orientation 125, but once the mobile device is rotated to be in a landscape orientation 130, the screen may appear dark or black, and vice versa. In some examples, problems may occur when the user may be able to view the mobile device screen 115 in a portrait orientation 125 or a landscape orientation 130, the image quality may degrade due to darkening, or color errors such as color fringes or color shifts may be introduced as the mobile device is rotated between orientations. The orientation and color shift issues may be addressed by introducing a high retardation film to depolarize the light before it leaves the mobile device.

[0035] As this article Figures 1A to 7 As discussed in , user 105 may be wearing polarized glasses or there may be a polarizing film between user 105 and mobile device screen 115, and user 105 may be able to view mobile device screen 115 in both a portrait position and a landscape position. Additionally, in some examples, the mobile device screen may emit light that may not be linearly polarized, allowing user 105 to view the mobile device screen in any orientation. In some examples, the mobile device screen may emit light that may have been circularly polarized, elliptically polarized, partially polarized, or randomly polarized.

[0036] In addition, the mobile device 120 may be capable of sensing user biometric data, such as a user fingerprint on the screen 115. In some examples, the mobile device 120 may use light emitted from the display layer as a light source for the sensing function. The mobile device 120 may include a display layer that may emit light to produce an image on the mobile device screen and may also serve as a light source for light reflected from a user's finger for sensing user fingerprint data. In this example, the light may propagate from the display layer along an optical path, pass through optical elements along the optical path, and also pass through the cover glass along the optical path, and may be reflected back from the user's finger through the cover glass. The reflected light may then return along a return optical path through all optical elements, through the display layer and to the sensor element. In some examples, the optical path may be in a first direction and the return optical path may be in a second direction. For example, the optical path may include a path from a light source to a reflective element such as a cover glass or a user's finger, and the return optical path may include a path from the cover glass or the user's finger to the sensor array. In some examples, either of the optical path and / or the return optical path may be referred to herein as a first optical path and a second optical path. Additionally, an optical path may be a path along which an optical element may be positioned, and the term optical path may be used interchangeably with the term light path. In some examples, light may propagate along an optical path or any of the light paths, and may pass through the optical element in either direction. In some examples, the sensor element may be a sensor array. The cover glass may at least partially reflect and partially transmit light. Optical elements that may allow light to pass in two different directions or along two different light paths will be discussed in further detail herein.

[0037] Figure 2 An exemplary layout of the optical system 200 is shown. In some examples, the optical system 200 may include a first optical delay element 205, a polarization element 210, a second optical delay element 215, and a reflective element 225 positioned along an optical path. The optical elements of the optical system 200 may be included in the mobile device of FIG. 1. In addition and as Figure 2 As shown, randomly polarized light may be provided to the optical system 200 .

[0038] like Figure 2 As shown, optical system 200 may illustrate a light path or optical path having light propagating from randomly polarized light source 220 through the optical elements of optical system 200. Figure 2In the embodiment of the present invention, the first optical delay element 205 can be an optical delay plate configured as a quarter wave plate. Generally speaking, the optical delay plate can be an optical plate with different amounts of birefringence and can be used to change the polarization state of light. The terms wave plate, optical delay plate and optical delay element are used interchangeably herein. Randomly polarized light can be transmitted to the first optical delay element 205, and the randomly polarized light can propagate through the optical delay element 205 and can also leave as randomly polarized light.

[0039] Randomly polarized light may be transmitted from the first optical delay element 205 to the polarization element 210. When the light passes through the polarization element 210, Figure 2 The polarizing element 210 can make the randomly polarized light linearly polarized. Figure 2 As shown, the linearly polarized light may be horizontally polarized, vertically polarized, linearly polarized at a 45 degree angle, or polarized at any other suitable linear polarization angle. The linearly polarized light may then be transmitted to the second optical delay element 215.

[0040] In some examples, the second optical delay element 215 may have a different delay value than the first optical delay element 205. In some examples, the second optical delay element 215 may have a delay value Re greater than about 1000 nanometers, and in some cases, a delay value Re greater than 8000 nanometers. The delay value of the second optical delay element 215 may be discussed in further detail herein. Polarized light may pass through the second optical delay element 215, and the polarized light may be randomly polarized by the second optical delay element 215. The randomly polarized light may then be transmitted to the reflective element 225. Although the delay element is described as a depolarizing element in the optical system 200, other types of depolarizers or depolarizing layers, such as a diffuser, may be employed in the system. The reflective element 225 may receive the randomly polarized light from the second optical delay element 215, and may reflect the randomly polarized light back toward the second optical delay element 215. The light path or optical path from the reflective element back through the optical system will be discussed in further detail herein.

[0041] Figure 3 An exemplary layout of an optical system is shown, and a cross-section of the mobile device 120 of FIG. 1 is shown. In some examples, the optical system 300 can be an optical stack, and can include a sensor array 320, a display layer 325, a first optical delay element 305, a polarization element 310, a second optical delay element 315, and a reflective element 330. The optical elements of the optical system 300 can be included in the mobile device of FIG. 1. In addition, some of the optical elements are numbered similarly, such as Figure 3 The first optical delay element 305 and Figure 2 The first optical delay element 205 may be a first optical delay element 205, and in some examples, these optical elements may share similar characteristics. Figure 3In the drawings, elements are not drawn to scale and may be thicker or thinner than depicted. Additionally, Figure 3 Elements of are depicted with space between each element. On mobile devices, Figure 3 The elements may or may not be spaced apart. In examples where the elements are spaced apart, the spacing between the elements may be equal or different.

[0042] A mobile device including optical system 300 may allow a user with polarized glasses to view the screen of the mobile device regardless of the orientation of the screen. For example, a user with polarized glasses may rotate the mobile device between a portrait orientation and a landscape orientation and still be able to see the screen while wearing the polarized glasses. Furthermore, a mobile device including optical system 300 may additionally be able to sense a user's fingerprint on the screen of the mobile device. These capabilities are discussed in further detail herein.

[0043] like Figure 3 As shown, optical system 300 may illustrate a first optical path that may propagate from display layer 325 through an optical element to reflective element 330, and a second optical path that may propagate from reflective element 330 through an optical element and display layer 325 to sensor array 320. Figure 3 In the embodiment of the present invention, the display layer 325 can be used as a light source for imaging on the mobile device screen and also as a light source for the sensor array. In some examples, the display layer 325 can be an organic light emitting diode (OLED). The display layer 325 can emit randomly polarized light along a first optical path to a first optical delay element 305, which can be a quarter-wave delay plate. The randomly polarized light can pass through the first optical delay element 305, and the randomly polarized light can leave the first optical delay element 305. In some examples, one or more quarter-wave delay films can be used for the first optical delay element 305. By using multiple quarter-wave delay films, the layer can be achromatic, thereby providing consistent performance at multiple wavelengths.

[0044] The randomly polarized light may then propagate along the first optical path to the polarizing element 310. The polarizing element 310 may be a linear polarizer and may linearly polarize the randomly polarized light as it passes through the polarizing element 310. In some examples, the linear polarizer may be a polyvinyl alcohol (PVA) film. The light may be linearly polarized horizontally, linearly polarized vertically, linearly polarized at a 45 degree angle, or polarized at any other suitable linear polarization angle. In some examples, due to the substantially vertical transmission axis of the sunglasses, the absorption of the polarizing element 310 may be 45 degrees to the horizontal axis. Even though the polarizing element 310 may block some light from passing through the layer, the polarizing element 310 may also mitigate cross contamination of the display illumination with undesirable internal reflections and backscattered light. Mitigating cross contamination of the display illumination will be discussed in further detail herein. The linearly polarized light may then propagate along the first optical path to the second optical delay element 315.

[0045] The second optical delay element 315 can receive linearly polarized light and can depolarize the light or randomly polarize the light. In some examples, the second optical delay element 315 can be a depolarizing layer and / or can be a high-retardation film. In some examples, the high-retardation film can be polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or any other suitable polyester film. The depolarizing layer can also be a film, such as a diffuser. In some examples, the second optical delay element 315 can be any film or layer that can depolarize light before the light passes through the cover glass of the mobile device and is observed by a user with polarized glasses.

[0046] In addition, the second optical delay element 315 may have a delay value Re greater than 1000 nanometers, and in some cases, may have a delay value Re equal to or greater than 8000 nanometers. A delay value of 8000 nanometers or greater may reduce the color shift between the horizontal mode and the vertical mode of the mobile device. Generally speaking, at a high delay value of 8000 nanometers to 10,000 nanometers or greater, the intensity dependence on the wavelength may be alleviated, so that the intensity may appear averaged over the entire wavelength range. In addition, the light output from the high delay film having a value in the range of 8000 nanometers to 10,000 nanometers (or greater) may have different polarization states at different wavelengths. Therefore, the user may view the mobile device screen while wearing polarized glasses, and may not see color errors or screen discoloration when rotating the mobile device. The second optical delay element 315 may provide randomly polarized light to the reflective element 330, and in some cases provide randomly polarized light to the user's finger that may be touching the reflective element 330. In some examples, the second optical delay element 315 may have a thickness in the range of about 4 microns to 7 microns. Using a high-retardation film having this thickness can allow the high-retardation film to be used in a mobile device while maintaining the form factor of the mobile device. For example, a high-retardation film having a thickness in the range of about 4 microns to 7 microns can be used in a smartphone or tablet while keeping the thickness of the smartphone or tablet about the same as the original thickness. In contrast, when used in any mobile device, a thicker film (such as greater than about 10 microns) can cause the mobile device as a whole to become thicker and change the overall aesthetics of the mobile device, its portability, grip, form factor, etc.

[0047] The reflective element 330 may reflect the received randomly polarized light, and the reflected light may also be randomly polarized. The light reflected from the reflective element 330 may propagate back from the reflective element 330 toward the second optical delay element 315 or the high delay film along the second optical path. In some examples, the reflective element 330 may be a cover glass and may be a material such as sapphire. In addition, the user may touch the cover glass with a finger, and the light may pass through the cover glass to reflect away from the user's finger, return through the cover glass, and propagate back toward the second optical delay element 315 along the second optical path.

[0048] The randomly polarized light that may be reflected from either or both of the reflective element 330 and / or the user's finger may pass through the second optical delay element 315. The light may still be randomly polarized after passing through the second optical delay element 315 and may be provided to the polarization element 310. Since the light provided to the polarization element 310 is randomly polarized, at least some of the light may pass through the polarization element 310. In some examples, when the light passes through the polarization element 310, the polarization element 310 may linearly polarize the light, and the linearly polarized light may propagate along the second optical path to the first optical delay element 305, which may be a quarter wave plate.

[0049] When the light passes through the quarter wave plate, the first optical delay element 305 can circularly polarize the received linearly polarized light. Depending on the orientation of the axis of the quarter wave plate, the circularly polarized light can be right circularly polarized or left circularly polarized. The circularly polarized light can then propagate through the display layer 325, which can be an OLED, to the sensor array 320. In some examples, the sensor array can be a microlens array. The light sensed by the sensor array can be used to determine physiological or biometric data of the user. In addition, in some examples, the optical system 300 can include a narrow field of view collimator between the sensor array and the OLED.

[0050] In some cases, light may be reflected back from the sensor array toward the display layer 325, but the reflected light may be circularly polarized. In one example, light incident on the sensor array 320 may be right circularly polarized, and light reflected from the sensor array may change handedness to become left circularly polarized light. Although the light may pass through the display layer 325 and the quarter wave plate 305, the light may not pass through the polarizing element 310. By stopping the light at the polarizing element 310, the image quality on the mobile device screen may be better due to the reduction of cross contamination of light emitted from the display layer 325 and circularly polarized light reflected from the sensor array 320.

[0051] Figure 4 An exemplary process flow 400 is shown. In some examples, Figure 4 The process flow 400 depicted in FIG. 4 may include Figure 4 Additional processes not depicted in or that can be excluded Figure 4 In addition, for discussion purposes, Figure 4 The processes are sequenced, but in some examples, they may be performed in a different order. Figure 4 In an example of FIG. 4 , process flow 400 may include a light propagation path through a sensing device.

[0052] exist Figure 4 In and at 405, the reflective element can be configured to reflect randomly polarized light toward the first optical delay element via an optical path. The randomly polarized light can be directed to the reflective element through the display layer via the optical stack, and the display layer can act as a light source for both the imaging and sensor arrays of the display. In some examples, the reflective element can be a cover glass of the mobile device and can be sapphire, and the reflective element can be partially transmissive and reflective, depending on multiple factors including the angle of incidence. In addition, light can be reflected by a user's finger touching the reflective element. Light from the reflective element and the user's finger can be reflected and / or backscattered. In addition, randomly polarized light incident on the reflective element can also pass through the reflective element to provide an image on the mobile device screen. Although relative to Figure 4 An optical path is described, but there may be more than one optical path in an optical system. In addition, and for purposes of discussion only, a path may be referred to as an optical path, a first optical path, and a second optical path, wherein any of these paths may be used to describe the propagation of light in either direction of the optical system, and these terms may be used depending on which element is initially introduced in the discussion, thereby affecting the description of in which direction light may propagate through the optical system.

[0053] At 410, the first optical delay element may be configured to receive at least randomly polarized light from the reflective element via an optical path. In some examples, the first optical delay element may be a high-delay film. The high-delay film may have a delay value greater than 1000 nanometers, and in some cases, may have a delay value equal to or greater than 8000 nanometers. A high-delay film having a delay value of 8000 nanometers to 10,000 nanometers or more may reduce the color shift between the horizontal mode and the longitudinal mode of the mobile device. In the case of a high delay value, the intensity dependence on the wavelength may be mitigated so that the intensity may appear averaged over the wavelength range, thereby reducing the color shift. In some examples, the first optical delay element may be a PET film, a PEN film, or any other suitable polyester film.

[0054] At 415, a polarizing element may be configured to receive at least light from the first optical delay element via the optical path. The polarizing element may be a linear polarizer and may linearly polarize the received randomly polarized light. In some examples, the linear polarizer may absorb light at about 45 degrees from the horizontal axis.

[0055] At 420, a second optical delay element may receive light via an optical path from a polarizing element. In some examples, the second optical delay element may be a quarter wave plate. The light received from the polarizing element may be linearly polarized light, and the quarter wave plate may circularly polarize the light. The handedness of the circularly polarized light (e.g., right circularly polarized light or left circularly polarized light) may depend on the orientation of the axis of the second optical delay element. In some examples, the second optical delay element may be a quarter wave plate and may be a cyclic olefin polymer (COP) film.

[0056] The sensor array may receive light via the optical path from the second optical delay element at 425. The light received from the second optical delay element may originate from a display layer adjacent to the sensor array, and the light may propagate through the first optical delay element, the polarization element, and the second optical delay element in two different directions before reaching the sensor array.

[0057] Figure 5 An exemplary process flow 500 is shown. In some examples, Figure 5 The process flow 500 depicted in FIG. 5 may include Figure 5 Additional processes not depicted in or that can be excluded Figure 5 In addition, for discussion purposes, Figure 5 The processes are sequenced, but in some examples, they may be performed in a different order. Figure 5 In an example of FIG. 5 , process flow 500 may include a light propagation path through a sensing device.

[0058] exist Figure 5 In 505, the light emitting layer may emit light along a first optical path toward the polarizing layer. The light emitting layer may be a display layer, and in some examples may be an OLED. The light emitting layer may provide light for imaging on a screen of a mobile device, and may also be a light source for a sensor array. The light emitting layer may emit randomly polarized light that may propagate to an optical element as described herein.

[0059] At 510, a polarizing layer may receive randomly polarized light from the light emitting layer and may polarize the received light. The polarizing layer may be a linear polarizer and may linearly polarize the light. The linearly polarized light may propagate along a first optical path toward the optical depolarizing layer. The linearly polarized light may be horizontally linearly polarized, vertically linearly polarized, linearly polarized at a 45 degree angle, or polarized at any other suitable linear polarization angle. In some examples, the absorption of the polarizing layer may be at 45 degrees to the horizontal axis. Even though the polarizing layer may block some light from passing through the layer, the polarizing layer may also reduce cross contamination of the display illumination with undesirable internal reflections and backscattered light. In some examples, the polarizing layer may be a PVA film. In addition, the polarizing layer may at least partially reduce and in some cases eliminate ambient light that may enter the mobile device and reflect and / or scatter and cross-contaminate imaging light from the display layer or OLED.

[0060] At 515, the optical depolarizing layer may receive linearly polarized light and may depolarize or randomly polarize the received linearly polarized light. The randomly polarized light may then propagate toward at least the protective layer. The optical depolarizing layer may be a high retardation film having a retardation value greater than 1000 nanometers, and in some examples, equal to or greater than 8000 nanometers, or equal to or greater than 10,000 nanometers. The retardation value equal to or greater than 8000 nanometers may reduce the color shift between the horizontal mode and the vertical mode of the mobile device when the user views the mobile device with polarized glasses. Generally speaking, at high retardation values ​​of 8000 nanometers to 10,000 nanometers or more, the intensity dependence on wavelength may be mitigated so that the intensity may appear averaged over the entire wavelength range, thereby reducing the appearance of color shift.

[0061] In some examples, the protective layer may be a cover glass for the mobile device screen. Randomly polarized light propagating toward the protective layer or cover glass may be partially transmitted through the cover glass for imaging on the mobile device screen, and may be partially reflected and / or backscattered back toward the optical depolarizing layer. Because the light is randomly polarized, the user is able to view the mobile device screen in any rotational position as described herein. In some examples, the randomly polarized light propagating toward the cover glass may also be incident on a user's finger touching the cover glass, and may pass through the cover glass and reflect back toward the optical depolarizing element. The light reflected and / or backscattered from the user's finger can be used to determine the user's physiological or biometric data, such as the user's fingerprint. This data can be used to verify the user's identity and unlock the mobile device or verify the identity of the user who is about to make a purchase, etc.

[0062] Figure 6 An exemplary process flow 600 is shown. In some examples, Figure 6 The process flow 600 depicted in FIG. 6 may include Figure 6 Additional processes not depicted in or that can be excluded Figure 6In addition, for discussion purposes, Figure 6 The processes are sequenced, but in some examples, they may be performed in a different order. Figure 6 In an example of FIG. 6 , process flow 600 may include an optical stack of a mobile device.

[0063] exist Figure 6 In and at 605, the cover glass may be disposed in the optical path. The cover glass may be sapphire and may be at least partially transmissive and partially reflective. At 610, the optical stack may be disposed adjacent to the cover glass and also disposed in the optical path. The optical stack may include various optical elements, such as a first optical delay plate, a polarizer, and a second optical delay plate, all of which may be disposed in the optical path. The first optical delay plate may be a high-retardation film and may be configured to randomly polarize any incident light received from the cover glass and / or the user's finger. In some examples, when the rotational position of the mobile device changes and the user is wearing polarized glasses, the high-retardation film may have a retardation value equal to or greater than 8000 nanometers to reduce color shift. In addition to the reflected light from the cover glass, the light received at the first optical delay plate may also include light that may be reflected by the user's finger touching the cover glass. The light from the cover glass and the user's finger may be reflected and / or backscattered. The polarizer may be a linear polarizer and may linearly polarize the randomly polarized light received from the first optical delay plate. The linearly polarized light may then be passed to the second optical delay plate, which may be a quarter wave plate. A quarter wave plate circularly polarizes light.

[0064] At 615, a display layer may be disposed adjacent to the sensing layer and may also be disposed in the optical path. The display layer may be a light source for imaging on a mobile device screen and may also be a light source for a sensor array. Circularly polarized light may pass through the display layer and may remain as circularly polarized light. The circularly polarized light may then propagate to the sensing layer.

[0065] At 620, a sensing layer may be disposed in the optical path and may sense light through the optical path and from the optical stack and through the display layer. The sensing layer may be a sensing device or a sensing array, such as a microlens array. The sensing layer may receive circularly polarized light and may reflect circularly polarized light having an opposite handedness back toward the display layer and the optical stack. Once the oppositely handed circularly polarized light encounters the polarizing layer, the light may not pass through the polarizing layer. In this way, reflected and backscattered light that may cross-contaminate the imaging light emitted by the OLED may be reduced and / or eliminated.

[0066] The following has been described for illustrative purposes Figures 1A to 6The layouts and configurations described herein may be used as part of an electronic device such as a watch, a biometric sensor, a laptop, a tablet computer, or any other suitable device.

[0067] Figure 7 An exemplary electrical block diagram of an electronic device 700 is shown, and the electronic device may be a reference Figures 1A to 6 The electronic device 700 may include a display 702 (e.g., a light-emitting display on the front side of the mobile device), a processor 704, a power supply 706, a memory 708 or storage device, a sensor system 710, or an input / output (I / O) mechanism 712 (e.g., an input / output device and / or an input / output port). The processor 704 may control some or all operations of the electronic device 700. The processor 704 may communicate directly or indirectly with substantially all components of the electronic device 700. For example, a system bus or other communication mechanism 714 may provide communication between the processor 704, the power supply 706, the memory 708, the sensor system 710, and / or the I / O mechanism 712.

[0068] Processor 704 may be implemented as any electronic device capable of processing, receiving, or sending data or instructions. For example, processor 704 may be a microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a digital signal processor (DSP), or a combination of such devices. As used herein, the term "processor" is intended to encompass a single processor or processing unit, multiple processors, multiple processing units, or one or more other appropriately configured computing elements.

[0069] It should be noted that the components of the electronic device 700 may be controlled by multiple processors. For example, selected components of the electronic device 700 may be controlled by a first processor, and other components of the electronic device 700 may be controlled by a second processor, wherein the first processor and the second processor may or may not communicate with each other. In some embodiments, the processor 704 may include any of the processors and / or may be capable of performing any of the processing steps described herein.

[0070] The power supply 706 may be implemented using any device capable of providing energy to the electronic device 700. For example, the power supply 706 may be one or more batteries or rechargeable batteries. Additionally or alternatively, the power supply 706 may be a power connector or a power cord that connects the electronic device 700 to another power source such as a wall outlet.

[0071] The memory 708 can store electronic data that can be used by the electronic device 700. For example, the memory 708 can store electronic data or content, such as audio and video files, documents and applications, device settings and user preferences, timing signals, control signals, data structures or databases, image data, biometric data, or focus settings. The memory 708 can be configured as any type of memory. By way of example only, the memory 708 can be implemented as a random access memory, a read-only memory, a flash memory, a removable memory, other types of storage elements, or a combination of such devices.

[0072] The electronic device 700 may also include a sensor system 710, which in turn includes one or more sensors positioned substantially anywhere on the electronic device 700 (e.g., the back side of a wearable device). The sensors may be configured to sense substantially any type of characteristic, such as, but not limited to, pressure, light, touch, heat, movement, relative motion, biometric data, and the like. For example, the sensors may include thermal sensors, position sensors, light or optical sensors, accelerometers, pressure transducers, gyroscopes, magnetometers, health monitoring sensors, and the like. Furthermore, the one or more sensors may utilize any suitable sensing technology, including, but not limited to, capacitive, ultrasonic, resistive, optical, ultrasonic, piezoelectric, and thermal sensing technologies.

[0073] I / O mechanisms 712 can send and / or receive data from a user or another electronic device. I / O devices may include a display, a touch-sensing input surface (such as a trackpad), one or more buttons (e.g., a graphical user interface "home" button), one or more cameras, one or more emitters and / or detectors (e.g., as described herein with reference to Figures 1A to 6 The I / O device or port may include a wearable device with a biometric sensor, one or more microphones or speakers, one or more ports such as a microphone port, and / or a keyboard. Additionally or alternatively, the I / O device or port may send electrical signals via a communication network such as a wireless and / or wired network connection. Examples of wireless and wired network connections include, but are not limited to, cellular networks, Wi-Fi, Bluetooth, IR, and Ethernet connections.

[0074] The above description uses specific nomenclature to provide a thorough understanding of the embodiments for explanation. However, it will be apparent to those skilled in the art that, after reading this specification, the embodiments can be practiced without specific details. Therefore, for the purpose of illustration and description, the foregoing description of the specific embodiments described herein is presented. These descriptions are not intended to be exhaustive or to limit the embodiments to the precise form disclosed. It will be apparent to those of ordinary skill in the art that, after reading this specification, many modifications and variations are possible in view of the above teachings.

[0075] The present disclosure recognizes that personal information data, including biometric data required to use the techniques described herein, can be used to benefit users. For example, the use of biometric authentication data can be used to conveniently access device features without using a password. In other examples, user biometric data is collected to provide users with feedback about their health or fitness levels. In addition, the present disclosure also contemplates other uses of personal information data, including biometric data, that benefit users.

[0076] The disclosure also contemplates that entities responsible for the collection, analysis, disclosure, transmission, storage or other uses of such personal information data will comply with established privacy policies and / or privacy practices. Specifically, such entities should implement and consistently use privacy policies and practices that are generally recognized to meet or exceed industry or government requirements to maintain the privacy and security of personal information data, including the use of data encryption and security methods that meet or exceed industry or government standards. For example, personal information from users should be collected for the legal and reasonable purposes of the entity and not shared or sold outside these legal purposes. In addition, such collection should only be carried out after the user's informed consent. In addition, such entities should take any necessary steps to safeguard and protect access to such personal information data, and ensure that others who can access personal information data comply with their privacy policies and procedures. In addition, such entities can subject themselves to third-party assessments to prove that they comply with widely accepted privacy policies and practices.

[0077] Regardless of the foregoing, the present disclosure also contemplates implementation scenarios in which users selectively block the use or access of personal information data including biometric data. That is, the present disclosure contemplates that hardware elements and / or software elements may be provided to prevent or block access to such personal information data. For example, in the case of a biometric authentication method, the technology of the present invention may be configured to allow a user to selectively bypass the biometric authentication step by providing security information such as a password, a personal identification number (PINS), a touch gesture, or other authentication methods known to those skilled in the art, either alone or in combination. In another example, a user may choose to remove, disable, or limit access to certain health-related applications that collect the user's personal health or fitness data.

Claims

1. A sensing device, comprising: Reflective element; a first optical delay element configured to receive depolarized light along an optical path from the reflective element; a polarization element configured to receive the light along the optical path from the first optical delay element; a second optical delay element configured to receive light along the optical path from the polarization element, wherein the first optical delay element has a greater delay than the second optical delay element; and A sensor array is configured to receive light along the optical path and to receive the light after the light has passed through the second optical delay element, wherein the sensor array is further configured to sense the light for determining physiological information of a user. 2 . The sensing device of claim 1 , wherein the first optical delay element is configured to transmit the depolarized light along a second optical path to the reflective element.

3. The sensing device of claim 1, wherein the first optical delay element is further configured to receive depolarized light and reflected light from the user's finger along the optical path. The sensing device of claim 1 , wherein the first optical delay element has a delay value greater than 1000 nanometers.

5. The sensing device of claim 1, wherein the first optical delay element has a delay value greater than 8000 nanometers.

6. The sensing device according to claim 1, further comprising: An organic light emitting diode configured to receive light from the second optical delay element and transmit the light to the sensor array.

7. The sensing device of claim 1, wherein the polarizing element is further configured to absorb light at an angle of 45 degrees to a horizontal axis.

8. The sensing device of claim 1, wherein the reflective element comprises sapphire.

9. The sensing device of claim 1, wherein the first optical delay element is further configured to receive polarized light along a second optical path from the polarization element and transmit randomly polarized light along the second optical path toward a reflective element.

10. An optical system, comprising: a light emitting layer configured to emit light along a first optical path toward the polarizing layer; the polarizing layer configured to polarize light and transmit the polarized light along the first optical path toward the optical depolarizing layer; and The optical depolarizing layer is configured to randomly polarize the received polarized light and transmit the randomly polarized light along the first optical path toward at least the protective layer. 11 . The optical system of claim 10 , further comprising a sensor array configured to receive light along the second optical path from the optical depolarizing layer, wherein the received light is used to determine physiological information of a user.

12. The optical system of claim 10, wherein the optical depolarizing layer has a retardation greater than 8000 nanometers.

13. The optical system according to claim 10, further comprising an optical retardation layer disposed between the light emitting layer and the polarization layer.

14. The optical system of claim 10, wherein the protective layer is configured to reflect the randomly polarized light to the optical depolarizing layer.

15. The optical system of claim 10, wherein the optical depolarizing layer is configured to receive reflected randomly polarized light from a user's finger and along a second optical path.

16. The optical system of claim 15, wherein the polarization layer is configured to receive randomly polarized light from an optical retardation layer along the second optical path. 17 . The optical system of claim 15 , wherein the light emitting layer is an organic light emitting diode configured to emit light, wherein the emitted light is used to determine physiological information of a user.

18. The optical system of claim 10, wherein the optical depolarizing layer is at least one of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

19. A mobile device, comprising: a cover glass disposed in the optical path; an optical stack adjacent to the cover glass and disposed in the optical path, the optical stack comprising: a first optical retarder disposed in the optical path and configured to randomly polarize light; a polarizer disposed in the optical path; and a second optical retarder disposed in the optical path, wherein the first optical retarder has a greater retardation than the second optical retarder; a display layer adjacent to the sensing layer and disposed in the optical path; and The sensing layer is disposed in the optical path and is configured to sense light received in the optical path, and the sensing layer is further configured to determine physiological information of a user using the sensed light.

20. The mobile device of claim 19, wherein the first optical retarder is configured to receive polarized light from the polarizer and randomly polarize the received polarized light.

21. The mobile device of claim 19, wherein the first optical retarder has a retardation greater than 8000 nanometers.

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