Fingerprint reader

Abstract

A fingerprint reader includes a screen comprising an array of energy-emitting pixels covered by a transparent layer, at least one sensor coupled along a cut edge of the display screen, a display driver that directs the array of energy-emitting pixels on the display screen to sequentially illuminate, and a microprocessor in communication with the display driver and the at least one sensor. The microprocessor knows the exact location and timing of the energy-emitting pixels' illumination. During use, when at least one finger is placed on the transparent layer and the display driver is activated, energy emitted sequentially from the energy-emitting pixels reflects the fingerprint onto at least one sensor. The energy received by the at least one sensor has varying intensity levels depending on the ridges and valleys of the at least one fingerprint. The at least one sensor sends a signal regarding the energy intensity level to the microprocessor. From there, the microprocessor creates an image of the fingerprint as the energy-emitting pixels sequentially illuminate.

Description

[0001] Divisional application

[0002] This application is a divisional application of application number 201680079680.8, filed on November 23, 2016, and entitled “Fingerprint Reading Device”.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims priority to U.S. Provisional Patent Application No. 62 / 258,863, filed on November 23, 2015, entitled “Remote Sensing Fingerprint Reading Device Operating on a Digital Display Screen.” Background of the Invention

[0005] 1. Technical field of the present invention

[0006] This invention relates to a display screen that allows fingerprints to be recorded anywhere on the screen, and also to a method for recording fingerprints anywhere on the screen without affecting the display function. This invention enables a mobile phone to read fingerprints anywhere on its display screen. Mobile phone manufacturers no longer need to allocate space on the front or back of the mobile phone for a dedicated fingerprint reader.

[0007] 2. Description of Related Technologies

[0008] Identity verification is a crucial issue in our digital and rapidly changing world. The challenge is how to securely verify personal identity. Credit cards can be lost or stolen. Image identification cards can be overlooked by security guards. A few years ago, several employees at a top-secret facility replaced their employee ID cards with cartoon characters (Mickey Mouse, Donald Duck, etc.) and subsequently gained access to the facility for several days. The fundamental challenge is verifying that when using a credit card or ID card, the card actually belongs to the individual making the purchase or obtaining access.

[0009] Fingerprints have been documented numerous times throughout history as a method of identification. While many fingerprints are believed to be accidental, others are decorative. However, researchers believe that some fingerprints on porcelain were deeply and deliberately inscribed, serving as a unique identifier of the creator or owner.

[0010] Fingerprint detection devices come in a variety of forms and formats, but all share the same goal: to accurately record the unique features of a finger, defined by its ridges and valleys. Fingerprints are defined by three levels of features. The direction of flow along ridges (Level 1) is typically categorized as arcs, loops, or spirals. Level 2 features describe large variations in the ridges, primarily bifurcations or endpoints. These Level 2 features are known as feature points and are the primary forensic use of the device. Features within and between ridges are known as Level 3 features and include sweat pores, scars, width changes, shape changes, wrinkles, breakpoints, and more.

[0011] Modern fingerprint sensors are electronic devices used to capture a digital representation of a fingerprint, known as a fingerprint image. There are many competing technologies for capturing fingerprint images, including pressure sensors, capacitive sensors, optical sensors, and thermal sensors. While "raw" captured fingerprint images can be stored for standard pattern matching, they are typically digitally processed to generate a more efficient biometric template (a collection of resolved features) for storage and matching. Regardless of the physical characteristics used to capture the fingerprint image, capturing high-quality (clear and contrasty) fingerprint images is crucial, as fingerprint image quality is crucial to the overall performance of the fingerprint system (see NIST 8034 Fingerprint Vendor Technology Validation [FpVTE2012]).

[0012] If the goal is to detect fingerprints anywhere on the display screen, a buried sensor array must exist under the entire display screen, which is very costly and complex. Currently, the most commonly used sensing technology is inductive, and charge induction is most effective when the sensor array is very close to the display surface. This results in unrealistic material thicknesses, and placing the sensor array in front of the LED light can interfere with display functionality.

[0013] Direct axis / optical solutions can address issues such as proximity to the screen, but they also require a large, high-density sensor array, miniature lenses, and increased thickness. These solutions must be able to "see through" the display's normal light-emitting layer, requiring the use of specialized materials with unique optical and electrical properties in the various layers between the display and the screen.

[0014] Optical fingerprint imaging involves using visible, ultraviolet, or infrared light to capture a digital image of the fingerprint. Essentially, this type of sensor is a specialized digital camera. In most architectures, the sensor consists of a clear touch panel that the finger presses against. Beneath the touch panel, a light source and lens are arranged using various optical elements to focus a clear, high-contrast image onto the lens sensor.

[0015] All modern fingerprint scanners use a sensor to capture a fingerprint, which involves sliding, rolling, or touching the finger across the sensing area. This process uses physical principles (in this case, optics) to capture the differences between the fingerprint's ridges and valleys. To achieve a high signal-to-noise (S / N) ratio, it's crucial that the image capture device's optical components preserve a clear, accurate, and high-contrast fingerprint image. Total internal reflection (TIR), and its cousin frustrated total internal reflection (FTIR), are physical phenomena often exploited by optical fingerprint readers to increase contrast and S / N ratio.

[0016] Total internal reflection (TIR) is an optical phenomenon that occurs when light strikes an interface at an angle greater than a certain critical angle (relative to the surface normal). If the reflection coefficient is lower than on the other side of the interface and the angle of incidence is greater than the critical angle, all of the light is reflected back into the original medium. This only occurs when light is traveling from a medium with a higher refractive index (n1 = higher refractive index) to a medium with a lower refractive index (n2 = lower refractive index). For example, this phenomenon occurs when light passes from glass to air, but not from air to glass. The critical angle is the angle of incidence required for TIR to occur. This angle is measured relative to the normal to the refractive interface.

[0017] A significant side effect of total internal reflection is the increase in evanescent waves at interface surfaces. In total internal reflection, although all incident light waves are reflected back into the initial medium, some penetrate into the secondary medium at the interface. These waves in the optically less dense medium are called evanescent waves.

[0018] If a third medium with a higher refractive index than the second, lower-index medium is placed near the interface between the first and second media, the evanescent wave can transfer energy from the second medium into the third. This process is called frustrated total internal reflection (FTIR). FTIR only occurs when the two high-index media are very close together (on the order of 1 / 10th of a millimeter). The dimensions of the ridges and valleys in a fingerprint are larger than the space required for FTIR interaction to occur. Therefore, when a fingerprint approaches and touches the glass, light is absorbed and re-emitted in all directions where the ridges touch the glass. However, the valleys are some 1 / 10th of a millimeter above the glass, and all light that strikes the touch panel surface at angles above the critical angle is reflected.

[0019] When the touch area is viewed from below the display glass (or other transparent surface), the valleys where they touch the glass appear one color and density, while the ridges appear another. Depending on the orientation of the light source and the viewing angle, the ridges appear brighter or darker relative to the valleys. In either case, the resulting high-contrast image is ideal for optical fingerprint readers such as digital cameras.

[0020] Most fingerprint sensors share a common characteristic: regardless of their method of operation, the finger must be in direct contact with the sensor. This is a significant disadvantage for mobile applications, as mobile users prefer to use fingerprint readers on the same surface they see (the screen). However, all current "screen" mobile fingerprint reader solutions require dedicated space on the front of the phone for the fingerprint sensor.

[0021] Furthermore, both users and manufacturers strongly prefer a flat, consistent glass cover across the entire front of the phone. In fact, some phone designers are considering covering the entire phone surface in glass. Glass's strength, scratch resistance, and hardness make it an advantageous surface material.

[0022] However, because all existing fingerprint sensors (sized for mobile phones) require direct contact with the finger, a hole must be cut into the glass to accommodate the sensor. This hole increases costs, requiring isolation from the surrounding environment and creating a weak spot in the glass. To avoid this hole, mobile phone manufacturers are looking for sensor technologies that can be placed under the glass.

[0023] A different approach scans an image and directs the resulting reflected light onto a sensor. The light intensity detected by the sensor can be scanned across a display screen, and the screen light intensity is varied to reflect the intensity detected to recreate the image. Because the image is free of distortion caused by focusing, this technique is widely used in scanning electron microscopes and many conjugate microscope designs. The image's viewing angle from the image source and the depth of field are significantly greater than with other imaging techniques. In relation to fingerprints, this fingerprint image generation method was used in U.S. Patent No. 4,553,837, "Roll Fingerprint Processing Apparatus," by Daniel H. Marcus in 1983.

[0024] Another optical system for scanning fingerprints is disclosed in patent application TW104208311. This application discloses a finger illuminated from below the sensor, and the image is projected onto a camera chip next to the sensor. FTIR is used to enhance the image of the ridges, so the ridges appear bright and the valleys appear dark. If the sensor is optically attached to the phone's glass cover (for example, by adhering the sensor to the glass using optically transparent adhesive with a matching refractive index), the glass becomes part of the sensor. Electrically, this invention focuses the image onto a digital camera, where the sensor pixels are scanned to produce a digital image. The resulting image can then be processed to remove distortion and perform feature point identification to determine the fingerprint's identity. The image appears as if viewed from the left. The image is naturally compressed by the length of the arrow but is full size in three dimensions. Careful use of the optical components must ensure maximum utilization of the camera chip. Even then, the image resolution (pixels per inch) may not be symmetrical. Image distortion is related to geometry and can be corrected to some extent using software. However, the resulting image is unlikely to be completely corrected and will never be a true 1:1 relationship with the original fingerprint. Furthermore, manufacturing tolerances limit how thin the structure can be made.

[0025] Attempts to address the issue of fingerprint sensing through the display have been made, including some phones that significantly alter the core display materials. Many of these materials are expensive and capital-intensive. Additional layers increase the thickness of the device. A straightforward solution would require placing a high-density sensor array under the display.

[0026] US Patent Application No. 2015 / 0036065 discloses the use of a sensor layer placed beneath the display, allowing fingerprints to be read anywhere on the screen without disrupting the phone's appearance during use. This published application describes adding a sensor layer "beneath" the display to read fingerprints. This differs from the typical approach used by most development teams to read fingerprints from screens. Most teams are exploring adding a layer "above" the display LED / LCD to bring the sensor very close to the finger. The trick is making that layer completely transparent so that the image transmitted through the display is not obscured. This approach is difficult to achieve.

[0027] Regarding early technologies that use displays to reflect fingerprints for reading, Apple has experimented with using pixels in the display as "sensing pixels." See U.S. patent application document number 2015 / 0178542, titled "Finger biometric sensor including drive signal strength updates and related methods."

[0028] US Patent Application No. 2015 / 0036065, titled "Fingerprint Sensor in an Electronic Device," discloses sensing multiple fingerprints directly from multiple fingers on a screen and mentions ultrasonic sensing of this information. While the ultrasonic concept is the closest to current inventions in the industry, it's not quite there. Furthermore, it may not require the sensor to physically correspond 1:1 with the desired details within the fingerprint image.

[0029] Further examining the issue, the size of fingerprint sensors used in mobile phones is determined by the trade-off between increased reliability (requiring a large sensing area) and reduced cost (which increases with the sensing area). Modern mobile phone sensors are being miniaturized to the limit while still providing sufficient reliability for the (relatively low) demands of mobile phone users. However, to provide adequate security for important financial transactions, mobile phone fingerprint sensors must be at least as reliable as the authentication chip systems used in credit cards. This would require a significantly larger fingerprint sensor size, which is not present in mobile phones. By allowing the entire screen to serve as a fingerprint sensor, there is no longer a practical limit on fingerprint sensor size.

[0030] In summary, a full-screen fingerprint solution currently does not exist. All known potential solutions require additional materials or layers within the display stack, and all involve the use of thousands of tiny sensors to measure fingerprint details. The current invention circumvents all of these issues by significantly reducing the number of sensors required, selectively relocating sensor elements from the perimeter of the screen to the edges, and utilizing continuous energy bursts and precise timing to create a fingerprint image. This device is capable of scanning the entire screen to detect the position of the finger in contact and measure the complex fingerprint features. For the remainder of this application, this system will be referred to as a remote sensing fingerprint reader. Summary of the Invention

[0031] One object of the present invention is to provide a fingerprint reader comprising the following: a display screen comprising an array of energy-scattering pixels enclosed by a transparent surface; at least one corresponding sensor on the edge of the display screen, directing the array of energy-scattering pixels of the display screen to a display driver that illuminates in a predetermined sequence; and a microprocessor that communicates between the at least one sensor and the display driver. The microprocessor knows the locations and exact times at which the energy-scattering pixels will illuminate. In use, when at least one finger is placed on the transparent surface and the display driver is activated, the energy-scattering pixels illuminate sequentially, reflecting the fingerprint onto the at least one sensor. The energy received by the at least one sensor has varying intensity levels depending on the ridges and valleys of the at least one fingerprint. The at least one sensor sends a signal to the microprocessor regarding the energy intensity level. As the energy-scattering pixels illuminate sequentially, the microprocessor generates an image of the fingerprint.

[0032] It is also an object of the present invention to provide a fingerprint reader comprising a memory for storing a fingerprint image generated by a microprocessor.

[0033] Another object of the present invention is to provide a fingerprint reader comprising an analog / digital converter disposed between at least one sensor and a microprocessor for converting an analog signal generated by the sensor into a digital signal used by the microprocessor.

[0034] It is a further object of the present invention to provide a fingerprint reader wherein the transparent cover layer is glass.

[0035] It is also an object of the present invention to provide a fingerprint reader wherein at least one sensor is a photosensor that measures energy intensity levels from an array of energy emitting pixels.

[0036] It is another object of the present invention to provide a fingerprint reader wherein the transparent cover is flat.

[0037] It is a further object of the present invention to provide a fingerprint reader wherein the transparent cover is curved.

[0038] Another object of the present invention is to provide a fingerprint reader comprising an energy conducting structure provided with a light sensor, the energy conducting structure being placed on a surface of a transparent cover and comprising an optical device for reflecting energy from a display screen to the light sensor.

[0039] It is a further object of the present invention to provide a fingerprint reader wherein at least one sensor (including a majority of sensors) is located on the edge of the transparent cover.

[0040] It is also an object of the present invention to provide a fingerprint reader comprising a touch sensor for locating the placement of at least one finger on a transparent cover.

[0041] It is another object of the present invention to provide a fingerprint reader comprising a lens or occlusion that provides improved illumination optimization for at least one finger.

[0042] It is an extended object of the present invention to provide a fingerprint reader in which energy received by at least one sensor is filtered to prevent unwanted energy from entering at least one other sensor.

[0043] It is also an object of the present invention to provide a fingerprint reader having at least one sensor that receives time-interval filtered energy from illuminated energy emitting pixels.

[0044] It is another object of the present invention to provide a fingerprint reader wherein energy-emitting pixels are included in a layer reflective to frequencies compatible with fingerprint detection.

[0045] It is an extended object of the present invention to provide a fingerprint reader in which certain adjacent energy-emitting pixels are collectively illuminated.

[0046] Another object of the present invention is to provide a fingerprint reader, wherein when the fingerprint reader is activated, energy-emitting pixels in the display screen area not used for fingerprint reading are turned off.

[0047] It is another object of the present invention to provide a fingerprint reader in which each energy emitting pixel is illuminated multiple times to generate a time-averaged fingerprint image.

[0048] It is a further object of the present invention to provide a fingerprint reader in which the color of energy received by at least one sensor can be measured and included in a signal sent to a microprocessor.

[0049] Another object of the present invention is to provide a reader comprising the following components: a screen comprising an array of energy-emitting pixels covered by a transparent layer; at least one corresponding sensor aligned with the edge of the screen; a driver that directs the array of energy-emitting pixels on the screen to illuminate in a sequence; and a microprocessor that communicates between the driver and the at least one sensor. The microprocessor knows the exact locations and times at which the energy-emitting pixels illuminate. When at least one finger is placed on the transparent layer and the driver is activated, energy from the sequentially illuminated energy-emitting pixels is reflected from the fingerprint onto the at least one sensor. The energy received by the sensor has varying intensity levels depending on the ridges and valleys of the fingerprint. The sensor sends a signal to the microprocessor related to the energy intensity level. The microprocessor then uses this signal to generate an image of the fingerprint based on the sequence of energy-emitting pixels that illuminated.

[0050] Another object of the present invention is to provide a touch position reader comprising the following components: a screen comprising an array of energy-emitting pixels covered by a transparent layer; at least one corresponding sensor aligned with the edge of the screen; a driver that directs the energy-emitting pixels of the screen to illuminate in a sequential manner; and a microprocessor that communicates between the driver and the at least one sensor. The microprocessor knows the exact location and timing of the illuminated energy-emitting pixels. When at least one finger is placed on the transparent layer and the driver is activated, energy from the sequentially illuminated energy-emitting pixels is reflected from the fingerprint onto the at least one sensor. The energy received by the sensor has different intensity levels depending on the location of the fingerprint on the screen. The sensor sends a signal to the microprocessor related to the energy intensity level. The microprocessor uses this signal to determine the position of the finger on the screen.

[0051] Other objects and advantages of the present invention will become apparent upon review of the following detailed description in conjunction with the accompanying drawings, which also set forth certain aspects of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Here's a perspective view of a phone with a current fingerprint reader.

[0053] Figure 2 1 is a configuration diagram of a fingerprint reader corresponding to the present invention, showing various functional components.

[0054] Figure 3 It is the fingerprint valley that is illuminated Figure 2 Diagram of the fingerprint reader configuration shown.

[0055] Figure 4 There is a fingerprint barrier that illuminates the Figure 2 Diagram of the fingerprint reader configuration shown.

[0056] Figure 5 A side view of a reflective object showing the energy of light shining on a finger.

[0057] Figure 6 、 7 , 8, and 9 are side cross-sectional views of the fingerprint reader corresponding to this invention.

[0058] Figure 10 This is a diagram of another specific version of the fingerprint reader.

[0059] Figure 11 yes Figure 10 A detailed perspective view of the energy transfer structure shown in Figure 5.

[0060] Figure 12 yes Figure 10 A diagram of another specific version of the fingerprint reader is shown here.

[0061] Figure 13 、 13A 13B and 13C are graphs of simulation results related to this fingerprint reader.

[0062] Figure 14 This is a configuration diagram of another specific version of this fingerprint reader.

[0063] Figure 15 、 16 It is a different specific version of this fingerprint reader in terms of the phone's viewing angle.

[0064] Figure 17 、 18 The figure shows the arrangement and configuration of sub-pixels and light sensors corresponding to this invention.

[0065] Figure 19 The figure shows the sub-pixel array configuration corresponding to this invention.

[0066] Figure 20It is a diagram showing the configuration of light-emitting pixels with a reflective surface on the bottom layer corresponding to this invention.

[0067] Figure 21 The figure shows the configuration of integrating the lens into the light-emitting pixel corresponding to this invention.

[0068] Figure 22 This is a diagram showing the arrangement of light-emitting pixels with a blocking layer corresponding to this invention.

[0069] Figure 23 This is a configuration diagram of a luminous pixel array corresponding to this invention that has both display and fingerprint reading functions.

[0070] Figure 24 FIG. 1 is an overhead view of a fingerprint reader corresponding to another embodiment.

[0071] Figure 25 、 26 is a touch sensor configuration diagram corresponding to this invention, wherein Figure 25 Is to show that the light-emitting pixels are aligned with the finger, and Figure 26 The display's illuminated pixels are not aligned with your finger.

[0072] Figure 27 This is a diagram showing the arrangement of light-emitting pixels with a blocking layer corresponding to this invention. DETAILED DESCRIPTION

[0073] The detailed examples of this invention will be disclosed here. However, it should be understood that the disclosed examples are only the best examples of the invention, which can be embodied in various forms. Therefore, the details disclosed here should not be interpreted as limiting, but only as a basis for people skilled in the art to make or use the invention. Figures 1 to 9 As can be seen from the specific examples disclosed herein, this invention provides a remote fingerprint reader 10 that allows a finger to be recorded anywhere on the display screen 12 of a mobile phone 14, and a method for recording a fingerprint anywhere on the display screen 12 without affecting the display function. More precisely, the remote fingerprint reader 10 allows the mobile phone 14 (or other electronic devices integrated with this invention) to read a fingerprint 100 placed anywhere on the display screen 12. This eliminates the need for mobile phone manufacturers to allocate space on the front or back of the mobile phone 14 for a separate fingerprint reader.

[0074] The remote sensing fingerprint reader 10 of the present invention scans the light source on the fingerprint 100 and then measures each scan position (refer to Figure 3 、 4) to generate a model of the fingerprint 100. With the present remote sensing fingerprint reader 10, when a finger 102 is placed on the display screen 12 of the mobile phone 14, it is illuminated by the display screen 12 and the fingerprint 100 is recorded by the sensor 16 within the range of the display screen 12. As a result of using the remote sensing fingerprint reader 10, the fingerprint 100 can be recorded by the display screen 12 without making any changes to the display screen 12 itself.

[0075] While this disclosure focuses on reading a single fingerprint on a display screen, it is recognized that a remote fingerprint reader can register multiple fingerprints semi-simultaneously. To semi-simultaneously register multiple fingerprints, the remote fingerprint reader 10 reads two or more areas on the display screen 12 using well-known touchscreen technology to allow the display screen 12 to determine the finger's position. By adding more authentication factors to the phone user's identity, multi-fingerprint recognition applications provide an additional layer of security (commonly referred to as "multi-factor authentication"). Further extending this concept, the relative position of two fingerprints may also be used in the authentication process. In other words, security is further enhanced if the relative alignment, distance, or angle between the two fingerprints is also read and recorded. For example, for bank transactions involving US$10,000 or more, the phone could require the user to place their two middle fingers at a specific location on the display screen 12. The fingers could also be required to be very close together and facing the 10 and 2 o'clock directions. In this case, someone attempting to steal more than US$10,000 would have to cut off two of the phone owner's fingers and learn how to arrange them on the screen.

[0076] More precisely, when a fingerprint 102 is placed anywhere on the display screen, the process begins when a light emitting pixel 18 beneath the fingerprint begins to illuminate. For the purposes of this application, a "light emitting pixel" 18 (or "energy emitting pixel") can be any pixel that emits light, whether it is generated within the pixel like an LED or OLED light source or the light passes through the pixel like an LCD display. Some of the light reflected by the fingerprint will be trapped in the transparent layer of the display screen 12 (such as the top glass layer). A photo sensor 16 is located on the edge of the transparent layer 34, which measures the energy (or change in energy) reflected or re-radiated from the reflection point. The energy reflected by the light emitting pixel 18 under the ridge is different from the energy reflected by the light emitting pixel 18 in the "valley" between the ridges. By sequentially illuminating the light emitting pixels 18 under the finger 102, measuring the reflected energy of each light emitting pixel 18, noting the difference between the ridges and valleys, and knowing the location of each light emitting pixel 18, an image / orientation map of the fingerprint can be created (see Figure 3 、 4The remote sensing fingerprint reader 10 does not require new layers or multiple sensors. This means it is low-cost, small in size, and does not affect the display.

[0077] Briefly and in accordance with a specific example of a remote sensing fingerprint reader 10, a display screen 12 includes an array 20 of light emitting pixels 18 covered by a transparent surface layer 34 (typically glass). In accordance with the specific example, the light emitting pixels 18 used with the present remote sensing fingerprint reader 10 will be the same as the light emitting pixels 18 used on the mobile phone 14 to generate images for the mobile phone user to view. In this way, with minimal modification, the remote sensing fingerprint reader 10 can be installed and used on existing mobile phones and other electronic devices with similar display screens. However, the following installation method is realized for this invention: a completely separate display screen 12 and light emitting pixel 18 array 20 are provided. When separate light emitting pixels are used (as shown below in comparison Figure 23 According to the explanation of the RFID reader, the pixels used with the remote sensing fingerprint reader (secondary pixels) may be separated from the normal "visible" pixel array (primary pixels) or they may be placed above or below the normal "visible" pixel array. For example, the separate pixel array may generate IR or UV frequency light waves that are invisible to the naked eye.

[0078] Furthermore, it is recognized that the present invention can be installed as a standalone device or as an accessory. A dedicated fingerprint reading device can be composed of the energy emitting pixels 20, the transparent layer 34 and other necessary parts.

[0079] At least one photoreceptor 16 is positioned adjacent to the edge of display screen 12. For example, photoreceptor 16 may be very similar to the camera in current cell phones 14, as these cameras are essentially photoreceptor arrays. These cameras are small, relatively inexpensive, and sensitive to light in the same spectrum as light-emitting pixels 18. Given the invention, instead of requiring millions of light-collecting pixels in an array within the camera, only a single light-collecting pixel is required for these cameras acting as photoreceptors 16. Consequently, all the details of fabricating a light-collecting pixel can be omitted, as the same chemistry and integrated circuit fabrication techniques can essentially be used to create a large light-collecting pixel.

[0080] While a light sensor 16 corresponding to an embodiment of this invention is disclosed, other sensors capable of capturing or measuring "light" electromagnetic energy are also contemplated. Similarly, according to the following disclosure, it is contemplated that the remote sensing fingerprint reader 10 utilizes the light-emitting pixels 18 of the display screen 12 as its energy source, and that these emitters are limited to "light." However, given that some LEDs and LCD panels used in the display screen 12 emit significant UV or infrared light, the sensor 16 need not operate within the "visible" spectrum and can operate in the UV or infrared regions. These elements are used to identify fingerprint ridges 1104 and fingerprint valleys 106.

[0081] The array of light-emitting pixels 20 provides an adjustable and movable (separate steps) illumination source for illuminating different areas of the fingerprint 100. If the light-emitting pixel 18 is located on a fingerprint barrier 104 (refer to Figure 4 ) or Fingerprint Valley 106 (reference Figure 3 ) will reflect differently from the light-emitting pixels 18. The transparent layer 34 acts as a medium for transmitting the reflected energy to the photoreceptor 16. The photoreceptors 18 emit light sequentially, and the remote fingerprint reader 10 records the different energy output spikes associated with each photoreceptor 18 to create an image or model of the fingerprint 100. To record the energy spikes from the photoreceptor 16 and create an image or model of the fingerprint 100, a computer program 22 running on the microprocessor 24 is required.

[0082] Specifically, the functional elements of the remote fingerprint reader 10 include the following: an array 20 of light-emitting pixels 18 and a display driver 26 that directs the illumination of the light-emitting pixels 18 on the display screen 12. The remote fingerprint reader 10 also includes a microprocessor 24 that communicates with the display driver 26 (and other components of the mobile phone 14). By communicating with the display driver, the microprocessor "knows" the location of the light-emitting pixels 18 and the exact time to illuminate them. It is also understood, as disclosed below, that the light-emitting pixels 18 can illuminate individually or in groups based on the instructions of the display driver 26 and the microprocessor 24. The single or multiple light sensors 16 are positioned to receive the reflected or emitted energy generated by the interaction between the fingerprint ridges 104 or fingerprint valleys 106 of the fingerprint 100 directly above the light-emitting pixel 18 and the illumination of the light-emitting pixel 18. Based on the resulting reflected energy from the interaction between the light emitted by the pixels 18 and the fingerprint, which is ultimately detected by the photo sensor 16, the photo sensor 16 generates a signal that is sent to the analog / digital converter 28, which converts the analog signal generated by the photo sensor 16 into a digital signal. This digital signal is then transmitted to the microprocessor 24. Based on the information related to the illumination of the pixels 18 and the signals generated by the photo sensor 16, the microprocessor 24 sequentially processes and combines the digital position of the pixels 18 with the dense data from the analog / digital converter 28 (and the photo sensor 16) to generate an image 52. The image 52 generated by the microprocessor 24 is then stored in the memory 30 of the remote fingerprint reader 10.

[0083] For example, the recording component of the remote fingerprint reader 10 can be the microprocessor and memory 30 of the mobile phone 14 (watch, computer, or other device) integrated with the remote fingerprint reader 10. However, it is acceptable to have a dedicated data microprocessor (or microcontroller) or other dedicated device that can be used in conjunction with the remote fingerprint reader. In other words, the remote fingerprint reader can be packaged as a "plug-in module" with a closed system that has established basic processing capabilities and sold as a "unit" integrated with the mobile phone. Such plug-in modules are very attractive to system engineers when integrating new functions into existing devices because they generally save time and complexity.

[0084] The data processing and recording corresponding to this invention will be completed in the following manner: When each light-emitting pixel 18 emits light, at least two pieces of information are sent to the processing unit and recorded. The first piece of information is the position (number or XY coordinate (reference) of the light-emitting pixel 18) where the light is emitted. Figure 3 、 4The second piece of information is the amount of energy reaching the photoreceptor 16. These two pieces of information are collected in the microprocessor 24 to calculate the range of light-emitting pixel 18 locations. A digital map is then created, with an array of numbers corresponding to the amount of energy received by the photoreceptor 16 at each light-emitting pixel 18 location. Because the energy levels of light-emitting pixels 18 hitting the photoreceptor 16 differ when they are under a "ridge" 104 and under a "valley" 106, the map will have some higher and some lower values. Overall, the light-emitting pixel array data directly corresponds to the fingerprint 100 image 52, indicating the locations of the ridges 104 and valleys 106.

[0085] After this image 52 is generated and stored in memory 30, the remaining steps, such as fingerprint analysis, extraction, and comparison, are standard. Various public and private methods exist for identifying individuals based on fingerprint "maps" or "images." The output of the remote sensing fingerprint reader 10 is compatible with all known fingerprint matching and elimination systems.

[0086] Specifically, the light sensor 16 outputs a voltage to the analog-to-digital converter 28. The digital-to-analog converter 28 provides a digital data signal to the microprocessor 24 in the remote fingerprint processor 10. The microprocessor 24 can then further manipulate this data. Numerous existing algorithms in the field of "digital image processing" can further enhance the digital data generated by the image to enhance clarity, contrast, or other purposes. Eventually, the microprocessor 24 (or microcontroller) or a dedicated device will access the image 52 stored in the memory 30 for further manipulation or identification.

[0087] The following concept is contemplated: the remote fingerprint reader 10 can be incorporated into various devices utilizing a display screen 12 and requiring quick and easy fingerprint reading. With this in mind, the remote fingerprint reader is described herein in conjunction with a mobile phone 14. Incorporating the remote fingerprint reader into the mobile phone 14 requires adding a light sensor 16 adjacent to the edge of the mobile phone's display screen 12, preferably at the edge 32 of the mobile phone's existing transparent layer 34. Such an integration also requires modifying the mobile phone's microprocessor 24 to coordinate information processing with the remote fingerprint reader 10. To this end, the output of the light sensor 16 must be recorded and combined with the individual light-emitting pixels 18 to form an image or map. This involves a standard analog-to-digital conversion and data manipulation process.

[0088] While the necessary components of the remote fingerprint reader 10 are already known, including a display screen 12 with an array of light-emitting pixels 20 enclosed by a transparent layer 34 and at least one photosensitive element 16, it is preferable to add additional components that can be used to direct the signal (light) to the photosensitive element 16. Based on this premise, a mobile phone 14 manufacturer who wants to install the remote fingerprint reader 10 would add a photosensitive element 16 around the display screen 12, add appropriate electronic components to perform general analog / digital conversion if necessary, program the display driver 26 to illuminate one light-emitting pixel at a time, and program the digital information to form an image or pattern. From this point on, the software, matching algorithms, and applications would operate much as they do today. For example, the system disclosed in Jain A.K., Hong L., Pankanti S., Bolle R., An identity-authentication system using fingerprints, Proc. IEEE 85(9) pp:1364-1388, 1997 (incorporated herein by reference) could be used in accordance with this invention. Jain describes a basic algorithm for identifying key points within a fingerprint image and using that key point pattern to uniquely identify the fingerprint's origin (owner). Similar algorithms are currently used in smartphones where the fingerprint reader is part of the phone.

[0089] More specifically, the scanning illumination used in the remote sensing fingerprint reader 10 is generated by activating one pixel 18 at a time within an array of light-emitting pixels 18 (e.g., individual OLEDs (organic light-emitting diodes) on the display 12 of the mobile phone 14). Light from each pixel 18 is sequentially projected onto a finger 100 within a close distance of the pixel 18. The reflected and re-radiated energy is then measured by the photoreceptor 16 to produce a digital output scan of the fingerprint 100 of the finger 102. Taking advantage of the directional nature of the OLED screen's light-emitting pixels 18 when located beneath the transparent glass 34 typically used with mobile phones 14, the image of the display 12 can be projected onto the finger 102 simply by placing the OLED display 12 in close proximity. The OLED display 12 can be used to generate a fingerprint image by using one or more photoreceptors 16 attached to the periphery (or a single side) 32 of the transparent layer 34 to detect light trapped by total internal reflection within the transparent layer 34.

[0090] When the following description discusses the implementation of a remote sensing fingerprint reader using an OLED display screen, pixel-type screen technologies that provide a separate light source are recognized, such as, but not limited to, liquid crystal display (LCD), light emitting diode (LED), plasma display panel (PDP), cathode ray tube (CRT) and other technologies that can be used according to the requirements of this invention.

[0091] Illuminating the light-emitting pixels 18 of pixel array 20 one at a time allows the remote fingerprint reader to generate a true, one-to-one model or image of finger 102 when placed over any active area of the internally illuminated display screen 12. As discussed in the Background of the Invention, illumination is scanned across the fingerprint, one light-emitting pixel at a time, and the reflected and re-radiated energy is measured and stored at each illumination point, rather than illuminating the entire finger with a common light source and capturing a complete image of the ridges with a digital camera chip. From this energy map, a fingerprint model or image can be reconstructed. (This document is incorporated herein by reference.)

[0092] refer to Figure 5 The illumination from a single pixel 18 is focused by lens 55 onto a small point on finger 100, and all reflected and re-radiated light from that point is captured by photoreceptor 16. As the illuminated pixel 18 moves to different positions relative to finger 102, the intensity of the reflected and re-radiated light changes. The intensity and / or color of the reflected and re-radiated light also changes depending on whether the illuminated pixel 18 is located over a ridge 104 or in a valley between ridges 104. A complete model or image of the fingerprint 100 is recreated by recording the captured energy levels at the XY coordinates corresponding to each illuminated pixel 18. The resulting image can be used similarly to any other digital fingerprint scan and / or positioned on a computer screen (or phone screen). A similar method is described in U.S. Patent No. 4,553,837, entitled "Rolled Fingerprint Processing Apparatus," by Daniel H. Marcus, 1983, the contents of which are incorporated herein.

[0093] One advantage of using illuminated pixels 18 to scan fingerprint 100 and generate an image at this low-resolution setting is that the viewpoint of the resulting image is from the illuminated pixels 18, rather than from the position of sensor 16. Any geometric distortion is therefore limited to the accuracy of the XY coordinates obtained at each sampling point. If transparent layer 34 is very thin, light emanating from LCD or OLED pixels 18 will only illuminate a small area on the transparent layer. Therefore, the lens focusing requirements are minimal or can be eliminated entirely.

[0094] Using a remote fingerprint reader 10 comprising the following components provides a true one-to-one fingerprint display without moving parts, geometric distortion, or distortion: an LCD or OLED pixel array 20, a transparent layer 34, and positioned light sensors 16. Complexity is reduced, and a typical modification to a mobile phone 14 requires only the addition of a single light sensor 16. Furthermore, the actual size of the captured fingerprint image is not limited by the sensor. The limitation is the size of the display 12, which is typically several times larger than a single fingerprint. Even with the smaller screens of typical smartwatches, the sensor 16 is often still larger than the finger (the overall display size on the watch screen). For larger devices like mobile phones 14 (or tablets, phablets, computers, etc.), it is possible to capture multiple fingerprint images simultaneously. The overall accuracy of the remote fingerprint reader 10 is significantly enhanced by not only acquiring more fingerprint data but also leveraging the geometric relationships between fingers.

[0095] exist Figures 6 to 9 The operation process of generating fingerprint images is shown in the Figure 6 Figure 3 shows the light-emitting state of pixel 18 when no finger is present. Some light from pixel 18 is captured by transparent layer 34 and can be directly illuminated by sensor 16 on the right. Additional light is transported to sensor 16 by total internal reflection. Some energy is refracted through the top surface 35 of transparent layer 34 and disappears.

[0096] When a finger 102 is placed and contacts the transparent layer 34, some Figure 7 The light shown therein will illuminate the edges 104 of the fingerprint 100. The light illuminating the edges 104 of the finger will cause the edges 104 to reflect and re-radiate the light, emitting light in all directions within the transparent layer 34. Figure 8 The light 8 in FIG. 8 represents the combined light from the illuminated pixels 18 and the reflected and re-radiated light from the interaction with the fingerprint ridges 104. Note that there is a higher number of light sensors 16 interacting on the right.

[0097] Figure 9 This shows a reflection and re-radiation from a light source that is not directly below a barrier rib (i.e., valley 106). In this case, the light will be scattered differently than when the rib is very close to the light source. This results in different levels of energy entering the light sensor 16. In this demonstration, note that Figure 8 In comparison, less light strikes the photosensor 16 .

[0098] In practice, the energy level received by photosensor 16 when the illumination source is directly above ridge 104 may be higher or lower than the energy delivered below valley 106. The increase or decrease in energy depends on the glass of transparent layer 34, the illumination spectrum, the source distribution method, the treatment of the contact surface, and other optical conditions. These details can be selected to optimize device performance based on the requirements. The important point is that the resulting total reflected energy will vary depending on whether the source is below ridge 104 or valley 106, and whether the activated energy-emitting pixels 18 are below ridge 104 or valley 106.

[0099] During the fingerprint 100 image collection operation, the entire display screen 12 can be used for scanning, or within the restricted scanning area 54 (refer to Figure 15 and 16 , which will be discussed in more detail below. The touch sensor 80 in the remote fingerprint reader 10 can be used to sense where a finger touches the display screen 12, and the remote fingerprint sensor 10 can direct a scan within the scanning area 44 adjacent to the contact point to sequentially activate the energy-emitting pixels 18. This device can direct the remote fingerprint reader 10 to begin operation when the touch sensor or touch screen reports that the finger 102 has touched the screen.

[0100] Although the specific examples disclosed herein are related to the placement of a transparent layer composed of flat glass, the basic principle can be applied to flat or curved glass (see Figure 5 ). Regardless of the curvature of the glass, reflected and re-radiated light passing through the glass will be refracted internally. If the glass is curved (such as the large curved edge of the Galaxy S6 or other smaller curved phones, watches, and devices), most of the light will continue to be partially reflected and trapped within the glass and then reflected internally, affecting and ultimately reaching the light sensor or light sensor 16 around the display screen 12.

[0101] Similarly, using this principle, fingerprints can be read directly on the curved section of the transparent layer 34. In fact, because some modern mobile phones have curved sections designed near the edge of the device's display, that is, within close range of the light sensor, curved surfaces may be better locations for fingerprint modeling or image capture.

[0102] Furthermore, this invention is not limited to reading a single fingerprint. Multiple fingerprints can be read simultaneously by illuminating a large area, or by scanning multiple areas under each fingerprint. The location of each important area can be determined by the touch sensor 80 used by multiple devices.

[0103] The light sensor 16 does not need to be placed at the "corner" edge of the transparent layer 34. A three-dimensional transparent structure 40 can be added to the glass surface to redirect the energy to a more convenient location. For example, referring to Figures 10 to 12 The embodiment disclosed therein shows a small, wedge-shaped energy-guiding structure 40 that can be placed on the top glass surface 35 of the transparent layer 34 of a cell phone 14. This energy-guiding structure 40 includes optical structures 42 that reflect energy from the display screen 12 toward one or more photo sensors 16 attached to the wedge 40. There are at least two reasons for using this embodiment. One implementation would involve a built-in energy-guiding three-dimensional transparent structure to better direct the signal to the photo sensor within the cell phone or device. All of these components are very small, with even the three-dimensional structure measuring only 1 to 2 millimeters. This would allow the photo sensor 16 to be two to three times larger, still small, and potentially cheaper or more sensitive. Alternatively, the three-dimensional transparent structure could be a more complex shape that guides light to an existing camera built into the cell phone. The camera would then become a dual-purpose device, serving as both the photo sensor 16 and a potential analog / digital converter, thereby eliminating the need for those components altogether.

[0104] When using such an energy structure 40, it is recognized that the light travels through the transparent layer 34 and then enters the input point 43 of the energy guiding structure 40. The use of such an energy structure 40 also requires it to be attached to the highest surface 35 of the transparent layer 34 of the display screen 12 by adhesive bonding. Under the above conditions, an optical adhesive 45 that can offset the effects of total internal reflection under the energy guiding structure 40 will be used to bond the input point 43 to the highest surface 35 of the transparent surface layer 34. A parasitic device that measures energy changes on each side of the glass can be used when physical placement (such as reinstalling an existing device) is beneficial. The light sensor 16 does not need to be placed next to the "corner" of the transparent layer 34. As in Figure 10 and 11 1 shows a small energy-guiding structure 40 that can be placed on the top glass surface 35 of the transparent layer 34 of the mobile phone 14. The energy-guiding structure 40 includes an optical structure 42 that reflects energy from the display screen 12 to one or more light sensors 16 within the housing 44 of the energy-guiding structure 40.

[0105] There are two reasons to use this specific example. One is to refit an old mobile phone 14. In this case and reference Figure 12In other words, one could place light sensor 16 inside an energy-guiding wedge and connect a cable to microprocessor 24, which would ultimately perform the aforementioned calculations, and USB link 46. A second placement would be an "upside-down" built-in energy-guiding structure, allowing energy-guiding structure 40 to be sunken into phone 14 rather than resting on a top surface. Furthermore, a more complex shape could be acceptable, directing light to an existing camera built into the phone. This camera would then become a dual-purpose device, also acting as a light sensor for the energy-guiding wedge, thereby eliminating the need for a light sensor altogether.

[0106] On typical cell phone OLED screens, the light-emitting pixels 18 are illuminated one at a time by the display driver 26 as needed during refresh. Display driver 26 technology has evolved from a simple sequential on-off approach across a uniformly lit backlight panel to a system that can make complex, discrete "on / off" timing decisions for each light-emitting pixel 18 over a significant portion of a full refresh cycle of the display. This is typically built around an "on / off" mechanism and a cycle of brightness changes across the entire device (in the case of displays using backlighting) associated with some range or pixel-level controlled brightness changes across the entire device. Many creative and effective technologies and solutions have been developed to achieve better balance, contrast, and consistency in the illuminated screen image. Much of this sophisticated technology in display control and lighting solutions is used to enforce the implementation of this invention.

[0107] Previously, we described a method for using a remote sensing fingerprint reader 10 that briefly turns on a pixel 18 and records the energy with the photosensor 16. Then, in preparation for the next time the pixel 18 is sampled, the pixel 18 is turned off. In the most basic configuration, each pixel 18 is not turned off, but remains "on" throughout the entire image 52 recording process. The remaining pixels 18 then illuminate. The last pixel 18 on the screen 12 remains on for the remainder of the time before the next refresh cycle begins. This is a cumulative illumination pattern observed by the sensor 16 as each pixel 18 turns on. The energy increase to the sensor 16 varies depending on whether the pixel 18 is located at a ridge or valley in the fingerprint. Therefore, the difference in the energy intensity curve indicates which pixel 18 is on or off, and an image or pattern is formed.

[0108] Simulation test results

[0109] A simulation test can be used to predict the signal data for a single scan line of a finger with 3 fingerprint edges in contact with the glass. Figure 13 Shows a setup with decent reflections, lots of attenuation, and ambient noise variations.

[0110] The light intensity from the source pixel 18 is assumed to be 100 (normalized to represent 100%). The average ambient light is assumed to be 100 times higher, or 10,000. The variance (time value -2x106 seconds) sampled at each pixel 18 is set to 0.1%. The signal attenuation is 1% per pixel 18 (relative to the next closest pixel 18) as the pixel 18 becomes increasingly farther from the sensor 16.

[0111] Figure 13A The data shown here represents the energy data when individual pixels 18 are sequentially illuminated and remain "on" throughout the entire cycle. Note that the curve appears to be a straight line. This signal appears to be overwhelmed by the increased energy and the overwhelmingly strong ambient lighting conditions.

[0112] To extract the signal, for each of the 18 pixels (n=1 to 36), the energy at pixel n-1 is subtracted from the energy at pixel n. We get Figure 13B The data simply reveals the presence or absence of fingerprint ridges in contact with the glass.

[0113] Because each data point is acquired independently of the previous one, the cumulative rounding error in this method is minimal. Each value is a mathematical expression, the product of two directly measured values. The only complication is the dynamic range of the sensor. This may require a sensitivity of up to 15dB. Small sensors with this capability are commercially available. The development of components with this capability is driven by the digital camera market and the development of semiconductor sensors with high quantum efficiency, such as CCDs and CMOS. Many current digital cameras (including cell phone cameras) have millions of sensors with this sensitivity level, limited by the overall digital sensor size and expected resolution. For example, the "New Imaging Technologies" at Verrieres Ie Buissons, France, offer digital sensors with a dynamic range exceeding 140dB. A single large-area sensor 16 using these technologies can have a significantly higher dynamic range than required for this invention.

[0114] Figure 13C This figure shows incident energy data from sensor 16 in a device where individual pixels 18 were turned on and off at various locations. The simulated energy data is identical to the cumulatively adjusted version. While the actual signal strength remains the same, the integration of the remote fingerprint reader 10 offers the advantage of measuring each energy spike on a common basis. This eliminates the need for subtraction when extracting the signal, and significantly reduces the dynamic range requirements of sensor 16.

[0115] Note that in all cases, even with cumulative energy, noise variations, and significant attenuation, large changes in incident energy can be easily resolved. For example, a pixel 18 that is not directly under a ridge or valley can be considered "half" on or off. The "on" side of a pixel 18 can be determined by observing the state of neighboring pixels 18. This allows interpolation to be used to increase the resolution of image 52, much like a touch-sensitive panel achieves relatively high resolution using a limited number of sensors.

[0116] Sensor efficiency enhancement

[0117] A practical problem facing remote sensing fingerprint readers 10 is how to improve fingerprint image quality without adding distortion that could hinder the ability to obtain a true reproduction of the fingerprint. Essentially, this involves improving the signal-to-noise ratio (abbreviated SNR or S / N). As those skilled in the art will recognize, SNR is a scientific and engineering term for comparing the expected signal level to the background noise level. It is defined as the ratio of signal strength to noise strength, typically expressed in decibels. While S / R is typically applied to electronic signals, it can be applied to any signal modality (such as isotope levels in the center of an ice cube or biochemical signals between cells).

[0118] In the case of a remote sensing fingerprint reader 10, the S / N ratio is a measure of the clarity of the fingerprint image when it is composed of pixels one by one. The S / N ratio can be enhanced by increasing the relative strength of the signal over the noise when the photosensitive sensor 16 records it. In this case, the source of the signal energy is the array 20 of light-emitting pixels 18 or the light-emitting pixels 16 that make up the display screen 12. Therefore, the S / N ratio of the fingerprint image can be enhanced by adding more energy to the initial signal and allowing more signal to reach the photosensitive sensor 16 that reads the signal. By reducing or eliminating random noise, the image will be clearer. For example and reference Figure 14 A filter 56 may be used with the photo sensor 16 to prevent unwanted energy or other elements from ambient noise from entering the photo sensor 16. In the simulation section, a large amount of ambient random noise is modeled, and some methods for minimizing this noise are discussed in the following description.

[0119] While it is recognized that all real measurements are subject to noise interference from, but not limited to, electronic noise and external events that affect the phenomenon being measured (e.g., wind, vibration, temperature changes, humidity changes, etc.), the remote sensing fingerprint reader 10 is most susceptible to ambient light.

[0120] The following paragraphs describe the signal collection method and instrumentation used by the remote fingerprint reader 10 to enhance the signal transmission from the light-emitting pixel 18 (or array 20 of light-emitting pixels 18), i.e., the light source, to the light sensor 16, i.e., the detector. To understand this specific example of enhancing the signal transmission from the light-emitting pixel 18 (or array 20 of light-emitting pixels 18) to the light sensor 16, it is important to understand that the light-emitting pixel array 20 provides an adjustable and movable (discrete step) illumination source for different regions of the fingerprint 100. If the light-emitting pixel 18 is located beneath the fingerprint barrier 104 or the fingerprint 106, the light from the light-emitting pixel 18 will be reflected differently. The transparent layer 34 acts as a medium to transport the reflected energy to the light sensor 16. The light-emitting pixels 18 illuminate sequentially, and the remote fingerprint reader 10 records the energy spikes associated with each light-emitting pixel 18 to create a model or image of the fingerprint 100. A program 22 is required to record the energy spikes from the light sensor 16 and create an image 52 (or model) of the fingerprint 100. In order to enhance the fingerprint image 52 to a level that allows feature point identification to be used to identify the owner of the fingerprint 100, the signal received by the light sensor 16 is enhanced by reducing the signal loss when the signal travels from the light-emitting pixel 18 (or the array of light-emitting pixels 18 20 ) to the light sensor 16 without distorting the image.

[0121] This can be achieved in various ways. Figure 20 A reflective pixel substrate 80 can be used as a support for the array 20 of light-emitting pixels 18. As a result, the spaces between the sub-pixels of the light-emitting pixels 18 can be made reflective at a desired frequency. This allows more signal energy to reach the photosensor 16 by reflecting significant energy back into the transmission medium rather than being absorbed in the substrate 80.

[0122] Corresponding to and referring to another specific example Figure 15 、 16 , the light sensor 16 is placed close to the location where the fingerprint is sampled. For a specific example like this, the remote fingerprint reader 10 defines a location on the display screen where the finger should be placed, known as scanning area 54, and focuses the fingerprint scan only on this area. Instead of scanning the entire display screen, which may have millions of pixels, the remote fingerprint reader 10 can focus its scan on only a few thousand illuminated pixels 18. This minimizes the number of active, energy-emitting pixels 18 and the data transmission requirements of the system and sensor. This increases the signal-to-noise ratio, requires less sensor dynamic range, and reduces power, time, and computational requirements.

[0123] The remote sensing fingerprint reader 10 instructs the user to place the finger relatively close to the light sensor 16 to enhance the signal authenticity. When the area of the display screen 12 being inspected is close to the light sensor 16, the signal difference between the ridge 104 and the valley 106 will be the strongest. This may be critical in adverse environments where the ambient noise is high to annoying. In this case, the remote sensing fingerprint reader 10 can instruct the user to place the finger 102 preferentially near the light sensor to enhance the clarity and strength of the signal. For example, if the remote sensing fingerprint reader 10 is only composed of a right cut edge of the display screen 12 (reference Figure 16 ) light sensor 16, the light sensor 16 can detect the fingerprint ridges 104 and valleys 106 of the finger 102 anywhere on the display screen 12. However, if the finger 102 is placed very close to the right edge of the display screen 12, the light sensor 16 will receive a stronger signal. Instructing the user to place the finger 102 close to the display screen 12, or even with only half of it on the edge of the display screen 12 (directly above the light sensor 16), the light sensor 16 will receive a stronger signal. This can provide design or marketing advantages for a long-range fingerprint reader 10 built with the light sensor 16. For example, the physical packaging of the sensor may be cheaper or have other advantages (thinner, lighter, smaller, etc.). If the system instructs the user to place the finger very close to the edge of the display screen, or even with part of it outside the edge of the display screen (partially on the sensor), the sensor will receive a stronger signal and the finger can act as a shield against ambient light sources near the sensor.

[0124] With this in mind, the remote fingerprint reader 10 can be equipped with multiple light sensors to ensure that a light sensor is recognized near multiple different touch locations. For example, light sensors can be installed on both the left and right sides of the display screen to more efficiently and conveniently serve left-handed or right-handed users. Placing light sensors at the top and bottom of the display screen is more convenient for users with large or small hands who are accustomed to using the "Home" button for fingerprint recognition. Light sensors at the top and bottom edges of the display screen provide efficient sensing locations for devices that do not have a specific "top" or "bottom" edge. Signal transmission efficiency may be enhanced when the touch point requires a finger to be placed near the light sensor 16 on two adjacent edges. This is particularly useful when the lighting is polarized.

[0125] Compared to using a single photosensor, using multiple discrete photosensors around the transparent glass surface to simultaneously collect both reflected and re-radiated energy offers the opportunity for more efficient energy collection. Multiple photosensors can be used in conjunction with temporal filters to enhance the signal-to-noise ratio. If a finger is placed very close to one photosensor and very far from another, the photosensor closer to the finger will receive the signal first, while the other photosensor will receive the signal slightly later. Because the remote fingerprint reader knows the relative position of the finger to the photosensors, the timing of the arrival of the signals at the different photosensors can be accurately calculated. Signal characteristics (e.g., magnitude, frequency, dwell time) can be measured at each photosensor 16 and then compared to a base "format" signal or to each other to additively enhance the signal and potentially cancel or ignore noise components originating from sources other than the finger's position.

[0126] Adding a continuous photodetector 16 around the transparent glass layer is also of interest. For example, thin-film solar photovoltaic technology could be one approach for implementing this specific example. Providing a relatively large area for the continuous photodetector 16 will collect more signals, and the opportunity to cover the entire area ensures that none of the stronger local signal energy that leaves the transmission layer is missed. Nearly all the energy generated by the lighting reaction will be collected.

[0127] It is also contemplated that it is possible to selectively create a reflective surface around the transmission layer to redirect signal energy back into the transmission medium (i.e., the light-emitting pixel or pixel array) before it leaves for the photoreceptor. This allows the photoreceptor 16 to capture signal energy that would otherwise be lost. There are several commercially available methods for creating a dielectric-on-glass surface that is transparent to the relevant wavelength range. For example, a silver coating with an adhesion catalyst can be used to aid bonding to the glass and a protective layer against oxidation and damage.

[0128] It's also contemplated that one could add a light collector to the edge of the transparent glass layer to collect all the energy for one or more photosensors. This would essentially be a "light pipe" around the edge of the transmission layer, or on the surface of the transmission layer. All energy reaching the collector on the edge or surface of the transparent glass layer would be inserted into the light pipe (or light collector) and transmitted to one or more remotely located photosensors.

[0129] The use of a full-area light sensor under or within the display is also being considered. This differs from the previously described remote fingerprint reader, where the light sensor is not remotely located around the display. However, the basic operating principle is the same, using light-emitting pixels to illuminate a small portion of the fingerprint in sequence. Having a full-area light sensor allows remote fingerprint readers to capture the first reflected energy from the light-emitting pixels.

[0130] Furthermore, similar to the above embodiment, an array 30 of light sensors 16 can be placed below or integrated into the display screen 12 (see Figure 17 、 18 ). There are other attempts on the market to obtain fingerprints under the glass layer of mobile phones, watches or other devices with display screens by using optical sensors. A big challenge is to create a sensor with a resolution of 500PPI and train each sensor 16 to only observe energy coming from directly above the sensor 16, which is basically a very narrow field of view. Bringing the sensor 16 closer to the surface requires very thin glass and will affect the durability of the device. A popular option used by IDEX and other developers is to create lenses or channels to control the divergence of light. This can be achieved using advanced materials (such as clear media or IR transparent media), but these steps will damage other aspects of the display. None of these attempts have entered the mass production stage, in principle because the compromises required in the design make the large-scale placement process impractical.

[0131] The method of this invention uses the timing of sequential illumination of display pixels so that the array of photosensors 16 preferentially detects energy reflected or re-radiated from a "source" closer to the display screen 12, rather than closer to the photosensors 16. The photosensors 16 do not need to interfere with the visual performance of the screen and can be located in front of, integrated into, or behind the active display screen. Lenses can be used to focus the energy from the pixels, but photosensors do not necessarily require lenses or focusing. Photosensors only need to detect the magnitude and / or frequency of the energy, not the direction. This implementation utilizes the microprocessor 24 to perform the necessary calculations.

[0132] An advantage of distributing the array 60 of photosensors 16 across the display screen 12 of the remote fingerprint reader 10 is that detection can be localized to isolate noise. That is, the remote fingerprint reader 10 can register energy only from photosensors 16 located below or near the pixel 16 used to illuminate a portion of the finger. By the same token, an array of photosensors 16 increases signal strength because the photosensors 16 are relatively close to the illumination source. Furthermore, it is not necessary for each photosensor 16 to be associated with every pixel. Each photosensor 16 can monitor dozens, hundreds, or even thousands of nearby pixels. If the photosensors 16 are placed within or near the pixel array 20, they must be protected from direct light from the pixels 18. This can be achieved by simply placing the photosensors 16 in a location where light from the pixels 18 cannot directly enter or by providing a shield between the pixels 18 and the photosensors 16.

[0133] Signal authenticity enhancement

[0134] The remote fingerprint reader 10's array of light-emitting pixels 20 provides an adjustable and movable (in separate steps) illumination source for illuminating different areas of the fingerprint. If a light-emitting pixel 18 is located beneath a ridge or valley in the fingerprint, the light from that pixel 18 is reflected differently. A transparent layer 34 acts as a medium to transport the reflected energy to the photoreceptor 16. The light-emitting pixels 18 illuminate sequentially, and the remote fingerprint reader 10 records the energy output spikes associated with each pixel 18 to create an image or model of the fingerprint. Software is required to record the energy spikes from the photoreceptor 16 and create an image or model of the fingerprint.

[0135] In order to enhance the fingerprint image so that the identification of feature points can be used to identify the owner of the fingerprint, the signal received by the photosensitive sensor 16 can be enhanced by increasing the signal strength and strengthening the signal transmission without causing deformation. In accordance with a specific example, this can be achieved by providing overclocked light-emitting pixels 18. Some display drivers limit the brightness of the light-emitting pixels to avoid damage to the light-emitting pixels and other materials. The possible damage to the light-emitting pixels may be time-based for some materials, that is, if it is only maintained temporarily, higher energy is not harmful. Overheating is a common example. Corresponding to the remote sensing fingerprint reader 10, however, the surge of a single light-emitting pixel 18 may be much faster than human visual acceptance, resulting in an unusual visual display. This unusual use of the display screen opens up the possibility of safely using higher energy (especially if it is turned on / off). Another approach is that in the display pixel array of the mobile phone 14 or other device, the secondary light-emitting pixel group 70 briefly discussed above can be interspersed between the main light-emitting pixels 18, 18a, 18b, 18c. The main light-emitting pixel is responsible for the display screen 12 (refer to Figure 23 ) display function, the secondary pixel group 70 is specifically designed for use with the remote sensing fingerprint reader 10 and is specifically designed to tolerate higher energy without excessive damage or degradation. Based on the above premise, signal fidelity can be enhanced in various ways within the spirit of this invention. Except for those specific examples provided in the supplementary figures, these enhancements are achieved through calculations and processing performed by the microprocessor 24 described above.

[0136] For a specific example like this, sequential AOI (area of interest) optimization is performed to achieve the objectives of the invention. After a complete fingerprint area has been read and analyzed, the AOIs can be identified. For example, these could be luminous pixels 18 that are expected to be under an edge, near an edge, or near a feature point. The specific AOIs will depend on the method used to identify features in the fingerprint. Regardless of how they are defined, additional scanning procedures can then focus on luminous pixels (or secondary pixels) only near the area of interest (AOI). For example, in a subsequent scan, one option for optimization would be to illuminate only the area that is likely to be near a feature point and then reanalyze the image to increase the clarity of the features in that specific area.

[0137] In another embodiment, sequential block optimization is performed to achieve the present invention. In such a methodology, a first pass creates a "rough" image by illuminating groups of pixels 18 within a block or grid (e.g., 2x2, 3x3) to produce a stronger signal to the photosensor 16 at the expense of lower resolution. If finer resolution is desired, a second pass can be performed using smaller blocks (resulting in higher resolution), and a third pass can be optimized further, and so on. Subsequent passes can be selectively focused on applicable areas.

[0138] Furthermore, the authenticity of the signal can be verified by lighting each pixel 18 so that the illumination is concentrated on a small area of the touch screen 35 on the array 20 of pixels 18 (i.e., the top surface 35 of the transparent layer 34 of the remote sensing fingerprint reader 10 that will eventually be touched by the user). This increases the energy delivered to the specific point on the sampled fingerprint (increases the signal energy) and reduces the energy delivered to areas that are not being tested (reduces the noise energy). The focusing technique is accomplished by allowing the light to branch off quickly after leaving the touch plane 35, thereby providing a wide angle field of view to the user. Refer back to Figure 21 A simple implementation in a modern smartphone would include placing a microlens 48 on each pixel 18 or placing a group of pixels 18 with a focal length approximately equal to the distance to the pixel 18 on the touch panel opposite the transparent glass layer 34 serving as the transmission medium. Figure 22 and 27 Light control can also be achieved by providing a blocking film 49 around the light-emitting pixels 18. The blocking film blocks energy that would otherwise illuminate a larger area. Furthermore, the blocking film can be made reflective and shaped to direct excess energy to a smaller target area on the touch panel.

[0139] To achieve a wider field of view within the display screen 12, the focal length can be designed to be slightly shorter than the distance to the touch panel 35. Non-optimal focusing of the illumination may still have significant benefits in terms of energy efficiency within the sampled area.

[0140] Signal authenticity can also be enhanced by focusing signal detection on color variations that best interact with and reflect from a fingerprint. For example, in the RGB color space, flesh tones are typically more red than blue and green. Red can be a particularly dominant color, perhaps 40% more intense than blue and green, although there can be a 5% or greater difference between blue and green. Knowing that the signal (and SNR) is strongest in red, the remote fingerprint reader 10 focuses on variations specifically in the red portion of the spectrum. To further enhance authenticity, the remote fingerprint reader 10 can use the average reflected color components from a first scan pass while a finger is placed on the touch panel 35 to dynamically and locally determine the optimal signal frequency. This calibration process only requires determining the average color within the applicable area (not for each pixel 18 at the illumination source). To achieve this measurement, the remote fingerprint reader 10 confirms that all pixels 18 within the applicable area are illuminated and then measures the spectrum of the reflected and / or re-radiated energy. Further optimization can be achieved by first predicting which segments of the light-emitting pixels 18 in the scanning area are likely to be edge reflections / re-radiations and which segments are likely to be fingerprint valley reflections / re-radiations, and then using this information to adjust the partial energy used to create the fingerprint.

[0141] Furthermore, the resolution of the sampling area can be increased using the secondary pixels 18a, 18b, 18c. Figure 17 In a typical full-color display, each luminescent pixel 18 is composed of sub-pixels such as red sub-pixel 18a, green sub-pixel 18b and blue sub-pixel 18c. When white light is used as the light source, the light source position can be assumed to be located in the center of the sub-pixel group. Alternatively, the sub-pixels of one color can be turned on to provide a slightly shifted image. Figure 17 In the image, each fully lit pixel 18 is composed of two green sub-pixels 18b (which light up together) and a red sub-pixel 18a and a blue sub-pixel 18c slightly below them. The red and blue sub-pixels 18a and 18c alternate from left to right. If one only uses the green sub-pixels 18b, the XY position of the light source, and therefore the captured image, will be slightly offset up and to the left of the "white" image. If one uses the red sub-pixels 18a, the XY position of the light source will be slightly to the lower left on the first row and slightly to the lower right on the second row. When using the blue sub-pixels 18c, the XY position of the light source will be slightly to the lower right on the first row and slightly to the lower left on the second row. The resulting composite image is obtained by taking the individual images for each color and aligning them according to the known sub-pixel positions. This results in an overall resolution twice that of the "white" image.

[0142] In another specific example, the applicable area can be divided into segments, each of which can be measured independently to enhance signal quality and potentially reduce the dynamic range requirements of the light sensor 16. Because scanning rates are very fast compared to human vision (typically 1 / 60 of a second for a full image), and the recognition rate of human fingerprints is much slower (up to a full second on some devices), the scanned area can be divided into smaller, more manageable segments that can be scanned one at a time. Multiple smaller scans reduce the dynamic range requirements of the light sensor 16 and minimize the chance of noise entering the system. For example, if the device aims to collect a 4 mm x 9 mm (500 PPI) fingerprint pattern or image, this requires approximately 14,000 pixels 18. Under a cumulative illumination setting (where each pixel 18 remains "on" during the sensing process), the light sensor 16 must be capable of detecting at least 14,000 different energy levels. If the system can perform a full scan in half a second, the device can divide the scan area into 30 segments, each with fewer than 500 light-emitting pixels 18. In this case, the photosensor 16 only needs to distinguish 500 different energy levels. This results in 8 bits of accuracy, compared to 14 bits for an unsegmented system.

[0143] When a special pixel (i.e., secondary pixel) 70 is specifically built into the display screen 12 for the remote sensing fingerprint reader 10 as described above and the pixels of the display screen 12 are used for general display operation, the special pixel 70 can be designed to be more optimized for the remote sensing fingerprint reader 10. Specifically, they can operate safely at higher energy to produce a stronger signal. They can be finely focused to ensure that only a small part of the finger is illuminated. They can operate at a specific wavelength that is noise-resistant, does not interfere with other operational goals, and is convenient for any economic or functional reasons. There are various options for achieving this construction. For example, an array of special pixels 70 can be built using the same materials and layers to coexist with the pixels used for general display functions on the display screen 12. The special pixel array 70 can be placed in a new upper layer, lower layer, or mixed with the pixels used for general display functions on the display screen 12. Or the special pixels 70 can be built completely separately from the display screen (i.e., directly as a standalone device that can operate with or without the display). For example and reference Figure 24 , a public, non-display fingerprint reader, which only has an array 20 of energy-emitting pixels 18 under a transparent layer 34 of a screen 12.

[0144] Temporary enhancement

[0145] To enhance the fingerprint image so that the identification of the key points can be used to identify the owner of the fingerprint, the noise in the signal can be removed without distorting the image by using appropriate filters as disclosed below. Except for those specific examples where additional figures are provided, these enhancements are achieved by performing calculations and processing using the microprocessor 24 described above.

[0146] In a specific example and with precise timing of the light-emitting pixels 18 on the display screen 12, equivalent performance to a lock-in amplifier can be achieved by timing the light from the light-emitting pixels 18 and ignoring any unintended energy that is not timed with the light source. This can, to a certain extent, address all noise sources, including ambient light.

[0147] Filtering can also be achieved using oversampling techniques. For a specific example, the area of display screen 12 to be scanned is scanned multiple times. Photosensor 16 continuously or intermittently monitors the signal during each sampling phase. Because the signal is regular and the noise is irregular, it is possible to enhance the SNR by averaging the measurements. This can be accomplished simply by acquiring more than one image and then combining them. Alternatively, the on-time can be increased to allow more signal samples to be acquired. In this case, the noise is reduced by the square root of the number of samples averaged.

[0148] The remote sensing fingerprint reader 10 can physically observe ambient light sources at the finger's vicinity when reading an image (not possible below), at or near the time the fingerprint is being read, and at the display screen 12 to filter, cancel, or compensate for the spectrum of incidental ambient light. One possibility for implementing such an embodiment is to repurpose a camera built into the device to monitor permanent ambient noise, specifically the portion of ambient light present within the narrow wavelength band of the RGB pixels 18. Ambient light can be averaged or measured over time to filter out cyclical noise, such as ambient light from electronic or electrical sources running at a 60-degree burst cycle.

[0149] Because many mobile phone displays 12 are composed of RGB pixels 18 that generate a single color within a narrow bandwidth, the remote fingerprint reader 10 can effectively drive the RGB components in an auxiliary manner in unused areas of the display 12 to use the known RGB component background to overwhelm random ambient noise and thus balance, offset, or normalize the effects of ambient light. Ambient light caused by the background that does not match the narrow RGB component can be ignored.

[0150] Similarly, the color of energy reflected from fingerprints can be monitored over time to detect signs of life (differences in blood color / flow). In this case, malicious forged "fingerprints" are treated like other types of noise and eliminated or used to identify other forensic devices, non-fingerprint "fragments."

[0151] A coating that reflects most (if not all) ambient light can also be applied to the top of the display screen, preventing it from entering the glass and reducing the noise reaching the photosensitive element 16. This reflective coating can also enhance internal reflections and increase the signal strength reaching the photosensitive element 16. If this reflective coating is knocked down by physical contact (the ridges of a fingerprint exhibit different reflective / re-radiative properties), the coating can increase the power ratio between the ridges and valleys of the fingerprint, thereby increasing the signal strength. This knockdown property is not uncommon in reflective coatings. Generally, this results in a higher signal-to-noise ratio. Reflective coatings and sensors can operate in a spectrum invisible to the human eye to minimize the impact on typical display device usage.

[0152] The industry is increasingly recognizing the wider range of applications for reflective coatings. In fingerprint readers, for example, an IR-reflective coating on the exterior surface can reflect unwanted image light away from the sensor. For example, in Jinji Technology's "hybrid" sensor, an IR coating on the top surface of the remote fingerprint reader 10 enhances the fidelity of the analog signal from the CMOS sensor. This applies to both transparent glass layers and the surface glass in "under-glass" applications. If the top surface of the transparent layer is treated (or selectively treated) with an IR-reflective coating, the contrast between areas with and without contact with the barrier ridges is emphasized. The reflective coating reflects a significant portion of the IR energy from the barrier ridges, or valleys, where the barrier ridges are not in contact with the coating. At the contact point between the barrier ridges and the reflective coating, the coating's reflective properties are defeated, allowing the IR energy to pass through to the CMOS sensor.

[0153] Continuing to consider various coatings that could enhance the operation of remote fingerprint readers, a light-absorbing or blocking layer could be applied to the transparent glass layer to prevent ambient light from entering the glass and adding noise to the system. Electrochromic glass offers the advantage of being able to be turned off under a finger, preventing ambient light from entering the glass except from beneath the finger, thereby preventing it from interfering with the fingerprint signal. E-ink (electrophoretic ink) is another potential candidate for blocking external light. For the blocking concept to work, a portion of the display must allow the fingerprint to alter the internal reflective properties of the transmitting glass when a light source illuminates sequentially under a ridge or valley. Due to the physical / optical changes at the contact points within the blocking layer, reflectivity will naturally change within the blocking layer, but this change may not be sufficient to create a strong signal. With conventional continuous blocking panels (such as electrochromic glass), it may be necessary to segment the display into zones that can be individually switched on and off, or to pre-define a specific area that can be kept "on" at all times, allowing fingerprints to be read only at that location. The complexity of a fully usable display such as a generally reconfigurable E-ink panel can be reduced by dividing it into segments, quadrants, or an open area that is predefined to read a single location of a fingerprint. The blocking characteristics of the E-ink or other blocking layer can be modified to block only frequencies that are not suitable for the operation of a remote inductive fingerprint reader.

[0154] Alternatively, a continuous blocking layer (a coating that blocks most light) can be applied to the top surface of the display to prevent most ambient light from penetrating the display and increasing noise. If this blocking layer is designed to pass only the narrow RGB wavelengths of the screen's emitting pixels (in other words, it allows the single-frequency red, green, and blue light created by the pixels to pass through but blocks all other light), this will have little or no effect on the display (it passes the RGB wavelengths), but it will block ambient light outside the RGB bandwidth. A significant component of ambient light is wavelengths outside the RGB bandwidth.

[0155] Backlight modulation can also be used to achieve the current enhancement goals corresponding to this invention. This is widely recognized by those skilled in the art of LCD technology and its widespread use in displays. LCDs do not inherently generate light, but instead rely on a "backlight" to illuminate the display. These backlights can be implemented using light-emitting diodes (LEDs), electroluminescent panels (ELPs), or cold cathode fluorescent lamps (CCFLs). In standard implementations, backlights provide a continuous, evenly distributed illumination that helps create an even, natural-looking image on the display screen. Some technologies (notably LEDs) are amenable to illuminating different portions of the display with different intensities and / or colors. This technology was developed to enhance contrast. Because most LCD technologies cannot block 100% of the light in areas of the display that should be dark black, these black areas can appear "gray." Furthermore, some LCDs emit white light with a non-optimal color temperature. This limits the range of colors that can be reproduced and causes humans to perceive colors differently in the presence of ambient light of varying color temperatures. Modern LED backlights are built using discrete groups of red, green, and blue diodes whose energy can be dynamically varied to suit the display's needs and the surrounding environment. Many of these displays are designed so that different areas of the display can be brightened or dimmed to suit the image content being displayed. For example, if an image of a brightly lit town against a dark sky is to be shown, the "town" area on the screen can be illuminated with normal LED backlight intensity, while the backlight intensity behind the "dark sky" in the image can be significantly reduced, making that portion of the screen appear very dim or black.

[0156] In accordance with this invention, modulation can be applied to the entire backlight, a block, or a single pixel. If the backlight can be temporarily completely shut down in the blocks not being used for finger sampling, the signal-to-noise ratio can be further enhanced. The off-cycle phase only needs to occur when the screen is driving the pixels 18 used for finger sampling. The off-cycle phase can be very fast (invisible to the naked eye) or slightly slower, depending on performance optimization needs.

[0157] Turning off pixels 18 after they've been used is another approach that can be used to enhance current performance. If the display driver turns off each pixel 18 after a period of time, this allows the photosensor 16 to sample each pixel 18 under normal, lower baseline energy conditions, rather than measuring the energy produced by the illumination of n+1 pixels 18 after accumulating unexpected light energy over time. If individual pixels can't practically be turned off sequentially within a screen refresh cycle, turning off pixels 18 in groups—for example, one scan line at a time—can be beneficial. This is similar to the concepts of segmentation and blocking described previously. However, in this case, blocking is performed within a refresh cycle.

[0158] Alternatively, an absorptive luminescent pixel substrate can be used in conjunction with a remote fingerprint reader. The substrate beneath the luminescent pixel is designed to absorb ambient light or light not important for fingerprint detection, but light generated by the remote fingerprint reader, particularly within the known unwanted energy spectrum. This can be achieved statically in the substrate's construction, or it may be possible to actively change the substrate's properties during fingerprint reading. This substrate can comprise electrochromic glass, E-ink, or other materials with alterable optical properties.

[0159] Signal signature analysis should also be usable with the remote sensing fingerprint reader 10. Certain characteristics of the signal (e.g., magnitude, frequency, dwell time) may be relatively constant, thus creating a predictable "signature" of the true signal. Signal signature analysis is widely used in manufacturing processes to monitor process consistency and ensure the quality of finished goods. Signal signatures or patterns can also be used to identify true signal data in the presence of noise. The information arriving at the photosensor 16 can be analyzed for characteristics that correspond to or are compared to a base "signal signature" that illuminates the pixel 18 triggering the data. This data is recorded as a fingerprint only when the appropriate signal signature is detected.

[0160] In another example embodiment, a micro-lens array can be placed above the illumination array of the light-emitting pixels to direct light to the appropriate locations on the fingerprint. In this case, using the appropriate lens combination, the illumination array can be larger than the fingerprint, so a relatively coarse dots per inch (DPI) illumination array can be used and focusing the illumination on a small area will increase the system DPI.

[0161] A key advantage of this invention over previous full-screen fingerprint scanning technology devices is that it does not require the sensor array and light array that are already part of every smartphone. So, only a simple light sensor needs to be added to the display screen 12, and the entire display can be used as a fingerprint sensor.

[0162] As discussed above, many transactions are less secure than anticipated. For example, most credit card transactions are completed with minimal fraud protection. The frequency with which credit card numbers are erased and reissued can be used as evidence of widespread fraud. Beyond financial transactions, access control is also a target for security breaches. This remote fingerprint reader 10 addresses concerns about using credit cards for online transactions via mobile phones because it uses a large, physical, and relatively secure fingerprint to confirm that the device (phone) is activated by the authenticated individual. However, it does not guarantee that the phone is currently in the possession of the correct person, a feature not comparable to image authentication or credit card authentication.

[0163] In addition to fingerprint reading, this remote fingerprint reader can detect / measure the color, outline, and shape of any object that touches the display screen 12. In its most basic form, the remote fingerprint reader 10 is a method for detecting surface features and colors. As a security device, it can be used on other body parts with unique shapes, textures, or colors (e.g., toe prints). It can also be used for custom "seals" or signatures. It can also detect raised features on flexible substrates like paper.

[0164] For example and reference Figure 25 and 26 It is possible to use the scanning system of the present invention as a touch position reader 11 to detect the position of an object that is touching the display screen 12 and thereby locate anything (such as a finger) that is touching the transparent layer 34 of the display screen 12. This is achieved by monitoring the reflected energy received by the light sensor 16 at the cut edge 32 of the transparent layer 34 while scanning the entire display screen 12. The light sensor 16 is emitted from the fingerprint (refer to Figure 25 The reflected energy received by the array 20 of light-emitting pixels 18 will be different from the reflected energy received from light-emitting pixels 18 elsewhere on the display screen 12. This can be used to identify the location of the light-emitting pixel 18 under the finger and, consequently, the location of the finger's contact point. Furthermore, this can be accomplished during normal operation of the display screen 12 without detracting from the visual performance of the display screen 12. Furthermore, a touch position reader 11 such as this would utilize similar functional components as described above with respect to the remote sensing fingerprint reader 10, such as the A / D converter 28, microprocessor 24, memory 30, and driver 26. Alternatively, by operating the light-emitting diodes at or beyond the limits of human vision (if the light-emitting diodes are illuminated very quickly or if the system uses an invisible light source such as IR), the operation can be essentially invisible to the user. IR can be emitted from specialized light-emitting pixels 18 built into the display or from another layer within the display stack. If the scanning process is fast and / or the scanning is done in a non-accumulative manner (i.e., the light-emitting pixels 18 are turned off (or changed back to the desired display color) after being used as the light source for the remote sensing fingerprint reader 10), hiding the scanning in the time zone can be naturally achieved.

[0165] Furthermore, the scanning system will be able to detect the shapes of other non-fingerprint objects. These could be other tactile biometric indicators (such as palm prints, etc.) or specially made "keys".

[0166] The system can be made sensitive to the color of the object touching the screen. This can further expand the application of screen scanning operations to detect colored objects and / or make biometric data more distinguishable (such as skin color).

[0167] With the ability to detect color and rapid scanning efficiency, it's possible to detect heartbeats by observing subtle changes in the color reflected and re-emitted from a fingerprint with each heartbeat. This can be accomplished during the fingerprint detection process or with an additional color-sensitive scan after the fingerprint has been verified. In a dedicated scan, the heartbeat signal can be amplified by summing the reflections and re-emissions over a large area. This can be used as a "standalone" vital sign detector. For devices like smartwatches or FitBit fitness devices, the display is large enough to serve as a remote fingerprint reader 10 and measure the wearer's pulse independently of the remote fingerprint reader 10. The remote fingerprint reader 10 can thus detect the fingerprint pulse and synchronize it with the heartbeat and the pulse of the person wearing the device. Furthermore, the pulse can be continuously monitored to confirm that the device has not been removed and worn by another person, thereby confirming that the person being identified by the device is the one currently wearing it. This provides a higher level of security for financial or access control transactions than any other currently available method.

[0168] The ability to read a fingerprint anywhere on the display 12 opens up numerous opportunities for applications or mobile software to be written that currently don't exist. Currently, the display 12 isn't optimized for reading fingerprints. The remote fingerprint reader 10 typically operates under a separate chip controlled by the software, so the area where the finger contacts the screen can be scanned at intensity, color, and scan rate settings optimized for fingerprint reading, rather than those used for the display. Under less optimized conditions, such as bright ambient light, an application could enhance the remote fingerprint reader 10 by directing the user to place their finger in a location optimized for fingerprint reading. Furthermore, when a fingerprint is to be read, mobile software could be written to illuminate an area around the optimized location to guide the user to place their finger in the optimized location. After the fingerprint is read, control of this area can be released, returning to the display.

[0169] The mobile phone software that prepares the screen for fingerprint reading can control where the finger is placed on the screen and can use the remaining screen to perform tasks that require fingerprint authentication. An example of fingerprint authentication is financial transactions such as Apple Wallet and similar credit card applications. When the fingerprint is read, the unused screen can be used to display a transaction code, such as a barcode for a single transaction (valid only for a limited time, such as 30 seconds). This increases the security of the purchase transaction. In transactions requiring user identity authentication, mobile phone software written to use the device screen as a fingerprint reader for enhanced security is also included in this invention.

[0170] Examples of mobile software like this, beyond financial transactions, include physical security features like access control systems (using a mobile phone 14 or Bluetooth system to replace ID card scanning or a mobile phone to replace a garage door opener). Mobile phone 14 can become a key for starting a car, unlocking a house door, turning on the air conditioner, or even a gun safety switch. When used in conjunction with mobile phone 14, security operations can be performed remotely. Bluetooth operation allows for convenient distance control. After mobile phone 14 verifies the owner's identity, it unlocks the door when the user is within close proximity.

[0171] Mobile software enables phone 14 to replace ID cards in high-security facilities using fingerprint sensors that meet the FBI standard specified in NIST SP800-76 (PIV). This is only possible with a fingerprint sensing area larger than the current sensor on the front panel of phone 14 (12.8mm x 16.5mm). Only back-mounted sensors (unpopular with users) and the full-screen sensor described in this patent can meet FBI standards. Once a phone 14's fingerprint sensor reaches this level of authentication reliability, it can be used for other security applications, such as authentication codes used by banking institutions in financial transactions.

[0172] While preferred embodiments have been shown and described, it is to be understood that there is no intention to limit the invention to this disclosure, but rather to cover all modifications and alternative constructions within the scope and spirit of the invention.

Claims

1. A fingerprint reader comprising: A display screen composed of an array of energy-emitting pixels covered by a transparent layer; at least one sensor coupled within or beneath the display screen; a display driver that directs the energy-emitting pixel array of the display screen to emit light in sequence; a microprocessor in communication with the display driver and the at least one sensor, wherein the microprocessor knows the location of the energy-emitting pixels and the exact time at which the light emission occurs; When at least one finger is placed on the transparent layer and the display driver is activated, energy emitted sequentially from each energy-emitting pixel is reflected from the at least one finger to at least one sensor. The energy received by the at least one sensor has different intensity levels depending on the ridges and valleys on the at least one fingerprint. The at least one sensor sends a signal regarding the energy intensity level to a microprocessor, which creates a fingerprint image while the energy-emitting pixels sequentially emit light. Furthermore, energy is filtered based on the timing at which the at least one sensor receives light from the illuminated energy-emitting pixels to prevent unwanted energy from entering the at least one sensor.

2. A fingerprint reader comprising: A display screen composed of an array of energy-emitting pixels covered by a transparent layer; a plurality of light sensors dispersed over an area of a display screen, the plurality of light sensors being located beneath the display screen and configured to measure energy from the array of energy-emitting pixels; a display driver that directs the energy-emitting pixel array of the display screen to emit light in sequence; a microprocessor in communication with the display driver and the plurality of light sensors, wherein the microprocessor knows the locations of the energy-emitting pixels where light emission occurs and the exact timing at which light emission occurs; When at least one finger is placed on the transparent layer and the display driver is activated, energy sequentially emitted from each energy-emitting pixel is reflected from the at least one finger to at least one of a plurality of photo sensors located adjacent to the emitting energy pixel. The energy received by each of the plurality of adjacent photo sensors has different intensity levels depending on the ridges and valleys on the at least one finger. Each of the plurality of adjacent photo sensors sends a signal regarding the energy intensity level to a microprocessor, which then creates a fingerprint image simultaneously with the sequential illumination of the energy-emitting pixels.

3. A fingerprint reader comprising: A display screen composed of an array of energy-emitting pixels covered by a transparent layer; a plurality of light sensors dispersed over an area of a display screen, the plurality of light sensors being located within the display screen and configured to measure energy from an array of energy-emitting pixels; a display driver that directs the energy-emitting pixel array of the display screen to emit light in sequence; a microprocessor in communication with the display driver and the plurality of light sensors, wherein the microprocessor knows the locations of the energy-emitting pixels where light emission occurs and the exact timing at which light emission occurs; When at least one finger is placed on the transparent layer and the display driver is activated, energy sequentially emitted from each energy-emitting pixel is reflected from the at least one finger to at least one of a plurality of photo sensors located adjacent to the emitting energy pixel. The energy received by each of the plurality of adjacent photo sensors has different intensity levels depending on the ridges and valleys on the at least one finger. Each of the plurality of adjacent photo sensors sends a signal regarding the energy intensity level to a microprocessor, which then creates a fingerprint image simultaneously with the sequential illumination of the energy-emitting pixels.

4. The fingerprint reader according to claim 2 or 3, further comprising a touch sensor for locating a position of at least one finger on the transparent layer.

5. A fingerprint reader according to claim 2 or 3, further comprising a lens or occlusion having features to assist in optimizing illumination of at least one finger.

6. The fingerprint reader according to claim 2 or 3, wherein: A plurality of adjacent energy-emitting pixels emit light in groups.

7. The fingerprint reader according to claim 2 or 3, wherein: Sub-pixels of the energy-emitting pixel are independently excited to improve resolution.

8. The fingerprint reader according to claim 2 or 3, wherein: The heartbeat on at least one device is continuously monitored to continuously confirm that the user's identity has not changed.

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