U.S. patent application number 13/289391 was filed with the patent office on 2012-11-08 for touch fingerprint sensor using 1-3 piezo composites and acoustic impediography principle.
This patent application is currently assigned to Sonavation, Inc.. Invention is credited to Isaac R. Abothu, Yakub Aliyu, Bryce M. Barbato, John Boudreaux, Patrick D. Brown, Jack S. Chorpenning, David B. Clarke, Deda Diatezua, Richard Irving, Omid S. Jahromi, Theodore M. Johnson, Ronald A. Kropp, Christian Liautaud, De Liufu, Walter C. Mick, Louis Regniere, William R. Robinson, JR., Rainer M. Schmitt, William H. Tanubrata, Honorio R. Ulep.
Application Number | 20120279865 13/289391 |
Document ID | / |
Family ID | 46025138 |
Filed Date | 2012-11-08 |
United States Patent
Application |
20120279865 |
Kind Code |
A1 |
Regniere; Louis ; et
al. |
November 8, 2012 |
Touch Fingerprint Sensor Using 1-3 Piezo Composites and Acoustic
Impediography Principle
Abstract
Provided herein is a method of making an integrated circuit
device using copper metallization on 1-3 PZT composite. The method
includes providing an overlay of electroplated immersion of gold
(Au) to cover copper metal traces, the overlay preventing oxidation
on 1:3 PZT composite with material. Also included is the formation
of immersion Au nickel electrodes on the 1-3 PZT composite to
achieve pad metallization for external connections.
Inventors: |
Regniere; Louis; (Boca
Raton, FL) ; Aliyu; Yakub; (Palm Beach Gardens,
FL) ; Schmitt; Rainer M.; (Palm Beach Gardens,
FL) ; Johnson; Theodore M.; (Palm Beach, FL) ;
Kropp; Ronald A.; (West Palm Beach, FL) ; Liautaud;
Christian; (Boca Raton, FL) ; Diatezua; Deda;
(Wellington, FL) ; Abothu; Isaac R.; (Wellington,
FL) ; Liufu; De; (Palm Beach Gardens, FL) ;
Irving; Richard; (Palm Beach Gardens, FL) ; Brown;
Patrick D.; (Lake Worth, FL) ; Mick; Walter C.;
(Wellington, FL) ; Tanubrata; William H.; (Lane
Park, FL) ; Jahromi; Omid S.; (Playa Vista, FL)
; Boudreaux; John; (Boca Raton, FL) ; Clarke;
David B.; (Palm Beach Gardens, FL) ; Chorpenning;
Jack S.; (Boynton Beach, FL) ; Barbato; Bryce M.;
(Jupiter, FL) ; Ulep; Honorio R.; (Mesa, AZ)
; Robinson, JR.; William R.; (Atlantis, FL) |
Assignee: |
Sonavation, Inc.
Palm Beach Gardens
FL
|
Family ID: |
46025138 |
Appl. No.: |
13/289391 |
Filed: |
November 4, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61410236 |
Nov 4, 2010 |
|
|
|
Current U.S.
Class: |
205/125 |
Current CPC
Class: |
C23C 18/54 20130101;
C25D 5/48 20130101 |
Class at
Publication: |
205/125 |
International
Class: |
C25D 5/02 20060101
C25D005/02 |
Claims
1. A method of making an integrated circuit (IC) device using
copper metallization on 1-3 PZT composite, comprising: providing an
overlay of electroplated immersion gold (Au) to cover copper metal
traces, the providing preventing oxidation on the 1:3 PZT composite
with material; and forming an immersion of Au nickel electrodes on
the 1-3 PZT composite to provide pad metallization for external
connections of the IC.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/410,236, filed Nov. 4, 2010,
entitled "Touch Fingerprint Sensor Using 1-3 Piezo Composites and
Acoustic Impediography Principle," which is incorporated herein by
reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention is generally directed to 1-3 PZT
composite sensors.
[0004] 2. Background Art
[0005] Improved concepts are needed for fingerprint touch sensors
based on the use of 1-3 piezo-composite and the principle of
ultrasonic impediography.
BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION
[0006] Embodiments of the present invention are made with respect
to principle sensor performance, sensor design and manufacturing as
well as packaging. Additional hardware and software implementations
are described addressing MTF performance. An improved concept for a
fingerprint touch sensor based on the use of 1-3 piezo-composite
and the principle of ultrasonic impediography is presented.
Improvements are made with respect to principle sensor performance,
sensor design and manufacturing as well as packaging. Additional
hard and software implementations are described addressing MTF
performance. The existing ASIC hardware is described separately in
the respective ASIC development description. The software package
for sensor control, data analysis and fingerprint presentations is
implemented and contained in USB software stick already distributed
to customers.
[0007] An exemplary sensor can have an area of up to 1.5'' by 1.6''
and an element pitch of 500 dpi. More specific features are
provided below that address improving the touch sensor by
packaging, sensor design, sensor construction, software/hardware
concepts for MTF control, and various sensing principles.
[0008] Further features and advantages of the invention, as well as
the structure and operation of various embodiments of the
invention, are described in detail below with reference to the
accompanying drawings. It is noted that the invention is not
limited to the specific embodiments described herein. Such
embodiments are presented herein for illustrative purposes only.
Additional embodiments will be apparent to persons skilled in the
relevant art(s) based on the teachings contained herein.
BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES
[0009] The accompanying drawings, which are incorporated herein and
form part of the specification, illustrate the present invention
and, together with the description, further serve to explain the
principles of the invention and to enable a person skilled in the
relevant art(s) to make and use the invention.
[0010] FIG. 1 is an STS 3050 assembly overview;
[0011] FIG. 2 is a diagram of flex circuit sensor connections;
[0012] FIG. 3 is a diagram of an exemplary sensor footprint;
[0013] FIG. 4 is an exploded (CAD) view;
[0014] FIG. 5 is an exemplary assembly step 1 mount;
[0015] FIG. 6 is an exemplary assembly step 2 mount;
[0016] FIG. 7 is an illustration of a bonding platform;
[0017] FIG. 8 is an exemplary step 3;
[0018] FIG. 9 is an exemplary step 4;
[0019] FIG. 10 is an exemplary step 5;
[0020] FIG. 11 is an exemplary step 6;
[0021] FIG. 12 is an exemplary step 7;
[0022] FIG. 13 is an exemplary step 8;
[0023] FIG. 14 is an exemplary completion step;
[0024] FIG. 15 is an exemplary step by step overview;
[0025] FIG. 16 is an exemplary sensor array;
[0026] FIG. 17 is an exemplary flex use for creating a package;
[0027] FIG. 18 is an exemplary molded base and touch sensor;
[0028] FIG. 19 is an exemplary 1-3 composite sensor using fine
pitch high density;
[0029] FIG. 20 is an exemplary flex with stiffener as backer;
[0030] FIG. 21 is an exemplary flex with plastic polymer with
molded base as backer;
[0031] FIG. 22 is an exemplary flex with plastic polymer with
molded base and bezel;
[0032] FIG. 23 is an exemplary flex with plastic polymer with
molded base and bezel (with the stakes pulled over);
[0033] FIG. 24 is an exemplary 3050 sensor structure diagram;
[0034] FIG. 25 is representative of exemplary sensor products;
[0035] FIG. 26 is representative of a first set of exemplary sensor
manufacturing processes;
[0036] FIG. 27 is representative of a second set of exemplary
manufacturing processes;
[0037] FIG. 28 is representative of assembly suggestions;
[0038] FIG. 29 is representative of 3050 sensor ultrasonic
experimental results;
[0039] FIG. 30 is an illustration of exemplary sensor bonding test
results;
[0040] FIG. 31 is an illustration of sensor side bonding test
results;
[0041] FIG. 32 is illustration of exemplary thermo compression
bonding;
[0042] FIG. 33 is an illustration of an ultrasonic bonding
experiment;
[0043] FIG. 34 is an illustration of simultaneous bezel and sensor
attachment;
[0044] FIG. 35 is an exemplary illustration of ACP use instead of
ACF;
[0045] FIG. 36 is an exemplary illustration of rigid and flex use
packaging;
[0046] FIG. 37 is an exemplary illustration bezel pre- attachment
to a sensor;
[0047] FIG. 38 is an illustration of experimental equipment;
[0048] FIG. 39 is an illustration of an experimental material
sample;
[0049] FIG. 40 illustration of experimental targets;
[0050] FIG. 41 is an illustration of a second set of experiments
targets;
[0051] FIG. 42 is an illustration of a test the layout on a
substrate;
[0052] FIG. 43 is an illustration of gold coated composite drilling
test results;
[0053] FIG. 44 is an illustration of a second set of gold coated
composite drilling test results;
[0054] FIG. 45 includes exemplary comments regarding gold coated
composites;
[0055] FIG. 46 is a first exemplary illustration of Ohashi ACF-10-
test equipment;
[0056] FIG. 47 is a second illustration of exemplary test
equipment;
[0057] FIG. 48 is a third illustration of exemplary test
equipment;
[0058] FIG. 49 is a fourth illustration of exemplary test
equipment;
[0059] FIG. 50 is a fifth illustration of exemplary test equipment;
and
[0060] FIG. 51 is an exemplary Sensor FEM Model evaluating sensor
performance properties for fingerprinting using impediography.
[0061] The features and advantages of the present invention will
become more apparent from the detailed description set forth below
when taken in conjunction with the drawings, in which like
reference characters identify corresponding elements throughout. In
the drawings, like reference numbers generally indicate identical,
functionally similar, and/or structurally similar elements. The
drawing in which an element first appears is indicated by the
leftmost digit(s) in the corresponding reference number.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0062] Embodiments of the present invention provide methods and
systems related to integrated circuit (IC) fabrication on 1-3 PZT
composite material. In the detailed description that follows,
references to "one embodiment," "an embodiment," "an example
embodiment," etc., indicate that the embodiment described may
include a particular feature, structure, or characteristic, but
every embodiment may not necessarily include the particular
feature, structure, or characteristic. Moreover, such phrases are
not necessarily referring to the same embodiment. Further, when a
particular feature, structure, or characteristic is described in
connection with an embodiment, it is submitted that it is within
the knowledge of one skilled in the art to affect such feature,
structure, or characteristic in connection with other embodiments
whether or not explicitly described.
[0063] Packaging. Exemplary packaging are illustrated in items 1 to
40 shown below.
[0064] 1.--Sensor on FLEX using ACF attach; existing technology, as
shown in FIGS. 1-15.
[0065] 2.--In line and/or staggered pads (patent pending). Folded
FLEX package for double sided sensors (STS3000 first
package)--method previously developed for tiger referenced as an
alternative concept creating a one sided ASIC attachment
scheme.
[0066] 3.--FLEX with stiffener as backer (eliminates backer
assembly step).
[0067] 4.--FLEX with plastic/polymer molded base (eliminates backer
assembly step).
[0068] 5.--FLEX with plastic/polymer molded base & Bezel
(eliminates backer & simplifies bezel assembly).
[0069] 6.--FLEX with plastic/polymer molded base & Bezel+heat
staking
[0070] 7.--ACF used to seal sensor /bezel interstitial gap, as
illustrated in FIGS. 20-23, for steps 3-7.
[0071] 8.--Conductive layer for ESD protection (For the touch
sensors we will need a conductive coating. ideally something we can
spin on not much thicker than what we do with SU8).
[0072] 9.--Vias in composite material (see, for example FIGS.
38-45) vias are connecting electrodes from one side of the sensor
to the other side facilitating bonding. Feasibility with drilled
and subsequently filled vias have been demonstrated previously;
three more via technologies have been evaluated: vias created in
green tiles and vias created within the dice and fill process as
well as vias created by laser drilling.
[0073] 10.--Thermal Compression ACF attach: a device for thermal
bonding developed and approved for mfg.--(FIGS. 46-50).
[0074] 11.--Ultra Sonic ACF. Ultrasonic bonding is proposed to
replace thermal ACF bonding reducing the heat risk.
[0075] See, for example, FIGS. 24-33 demonstrating thermal
bonding.
[0076] Provided are calculations for a manual operation using both
Thermal-Compression and Ultrasonic bonding methods with dual
bonding heads. No backer assembly is considered in this
calculation.
TABLE-US-00001 Sensor only Sensor only Sensor + Sensor + By US By
TC Bezel By Bezel By bonding bonding US bonding TC bonding Bonding
Tact 15 15 20 20 time For loading and alignment (sec) Bonding 5 15
5 15 time (sec) Total bonding 20 30 20 30 time (sec) Unit/min 6 4
4.8 3.5 (dual heads) Unit/month 90K 60K 72K 52K (unit) Unit/year 1
0.7 0.87 0.63 (Million unit)
The major advantages of the US bonding are: [0077] 1) Low
temperature fast bonding time [0078] 2) Less thermal damage to
sensor [0079] 3) Higher throughput
[0080] For bonding the 3050 sensor and bezel as well as the
proposed touch sensor the use of the MicroPack's 130 Dual Head US
bonder is of advantage, whether the US bonding can be successfully
done on the 3050 sensor plus bezel prototype assembly. If the test
results come out good, Sonavation can consider MicroPack as not
only an US bonding equipment manufacturer but also one of the
Sonavation's sensor assembly houses as the STARS in Thailand.
[0081] 12--Attach Bezel at same time as Sensor to create absolute
flat surface.
[0082] 13--ACP used for sensor to flex bonding
(dispense/spray/screen print): See, for example, ACP technique FIG.
35.
[0083] 14--Rigid+Flex substrate.
[0084] 15--Pre-attach Bezel to Sensor (create a single pick &
place part). See for example, FIGS. 34-37 and 46-50.
[0085] 16--Low temp ACF Bonding to FLEX or PCB.
[0086] 17--ACF Placement and flow control.
[0087] 18--Sensor Support (mechanical support for air gap).
[0088] 19--Pressure control Activation and release (HW team).
[0089] 20--Vacuum placement on bonder.
[0090] 21--Alignment of Bonder.
[0091] 22--Alignment Sensor to Bonder. See FIGS. 1-15. Ref/8/.
[0092] 23 ASIC /Mux for touch: ASICs mounted via sockets.
[0093] Sensor Design
[0094] 24 Support Pillars proof via FEM study. See FIG. 51.
[0095] Optimized sensor design balancing pillar length and width
and kerf, pzt and matrix material to maximize dynamic range
separating ridge and valley while providing adequate electrical
conditions (resistance at, resonance and resonance frequency).
Parameters are evaluated using a model developed for Falcon
geometry by selecting the appropriate parameters for Touch sensor
geometry. validated in
Touch Sensor
[0096] 24--Stitching 4 parts to make a bigger one--concept. See,
for example, FIG. 16 and FIGS. 38-45.
[0097] 25--Using 2 sides for connections to make above
possible--same as above).
[0098] 26--Folded FLEX packaging (similar to our first STS3000).
See FIGS. 17 and 18
[0099] 27--Touch interconnect using silver epoxy:
[0100] 28--Touch interconnect using very low temperature
solder:
[0101] 29--Packaging using an Interposer;
[0102] 30--SENSOR to PCB using FLEX as interposer:
[0103] 31--Sensor mounted on PCB subassembly
[0104] 32--ASIC mounted on PCB subassembly : Interposer drawing
requested from Y
[0105] Ref/12/
[0106] 33--Sensor mounted on PCB subassembly interconnect to ASICs
mounted on
[0107] PCB subassembly.
[0108] 34--Double sided PCB, sensor on one side and ASICs on the
other side--similar to interposer.
[0109] 35--In-line or staggered sensor pads.
[0110] 36--ASIC perimeter or staggered bond pad.
[0111] 37--Wire bonding ASIC & SENSOR TO PCB using highly
staggered PCB connections Ref/12/ more supporting material for
features 27-37 in progress
Touch Sensor Proof of Concept
[0112] 38 Main & Interposer boards
[0113] 39 Sensor to PCB attach process
[0114] 40 Separate Rx & Tx ASIC arrangement
[0115] 41 Clock & Reset synchronization of the surface prior to
surface activation using immersion in palladium (Pd) based
solution.
[0116] Current 1-3 composite of falcon geometry pitch 72 um, width
50 um and pillar height 150 um is approx 50 percent as measured
with laser vibrometry and predicted by FEM modeling. Crosstalk is
reduced, if the interstitional material exhibits a large difference
(preferably a lower) to the PZT, e.g. air. However air will not
keep the pillar in place. Currently Epotek 301-2 is deployed
providing sufficient bonding strength to keep the pillars in place
during grinding the process step exerting the largest force to the
pillar during manufacturing. However, material with much lower
acoustic impedance could be employed as for example epoxy fill with
hollow glass spheres having a diameter of <1 um.
[0117] Another possibility are nano porous polymers currently under
development, but with no known source of commercial production.
[0118] Note on Air like Backing of Transducers/Fingerprint touch
sensor
[0119] Problem: Air backing is of advantage for ultrasound
transducers as it increases the output amplitude by 30% according
to the Redwood Transient Model. For the fingerprint sensor air
backing is vital, as energy shall be transmitted in the front
medium only. In both cases the sensors front propagation material
is soft tissue a suitable backing must have much lower acoustic
impedance approximately 0.1 MRayl as estimated from earlier
calculations..sup.1 .sup.1 Hard backing would be a solution too.
However the hardest material, pure tungsten, has an ac. Impedance
of 100 MRay leaving us with reflection coefficient of
.about.0.74.
[0120] Particularly for the fingerprint touch sensor the backing is
required for stability.
[0121] Proposed solution: Rough surface. The surface roughness of
most material provides an interface to the fingerprint sensor,
which is only partial in contact with the active sensor. Typically
no acoustic contact is achieved without high static pressure. The
reduced contact area of a rough surface is equivalent to an air
like backing and can support the sensor.
[0122] Backing is provided by a layer sprinkled randomly with bumps
having diameter less than a pillars width. These bumps provide the
support for the sensor. Due to their round shape and small total
area the transmission into the backing is kept low. The average
distance between bumps will be chosen according the bending
strength of the 1-3 piezo composite. For fingerprinting each bump
may create a pillar failing reflecting the front loads. However, if
the fingerprint is over sampled, filtering out those locations will
not degrade the final result of the fingerprint matching schemes.
The random scheme is used to destroy phase coherence for any
transmission and wave propagation in the backing
Generating the Bump Feature
[0123] Bumps will be produced by a mold created from a random
pattern. The random pattern is generated by first calculating a sub
matrix with side length of half the stability distance of two
supporting points. Bump locations are then created randomly within
each sub-matrix, where the matrix length is much larger than the
bump diameter.
[0124] Non linear contacts at the bottom interface is modified to
the advantage of acoustic impediography for the acoustic load to be
estimated placed on the top and pressed down by a static pressure.
For example spherical random contacts are made at the interface,
which under no static load provide a certain contact area. If the
static load is increased, the contact area increase if a suitable
contact point material is employed, e.g. RTV. If the contact area
increases the damping is increase on locations where the acoustic
top load is in acoustic contact with the sensor. For a sufficient
resolution of this improved method a very flexible 1-3 composite
substrate is required.
[0125] Software (contained in the development kit sent to
customers: e.g. MAT
[0126] Libraries
[0127] SonicLib
[0128] Sparrow ASIC control and I/O
[0129] Mapping Tables
[0130] Dynamic Optimization
[0131] Bad Pixel detection and correction
[0132] Multiple ASIC capability
[0133] SonicPal--Platform abstraction layer (per platform)
[0134] Provides abstraction of hardware specific details and
certain operating system functions, such as debug I/O and memory
allocation.
[0135] SonicNav--Mouse and touch screen like navigation
[0136] PHAT based, or
[0137] Correlation based, or
[0138] Centroid based.
[0139] Inertial/Accelerator algorithm.
[0140] "Double Click" GUI algorithms.
[0141] Composer--Convert slices into fingerprint, non correlation
based.
[0142] Innovatrics--We own rights to E&M code.
[0143] Sensor Image-processing Algorithms
[0144] Bad Pixel Processing
[0145] Sensor Resonance Detection
[0146] Dynamic Optimization
[0147] Enrollment Min-Max algorithm
[0148] Navigation
[0149] Pulse Rate (experimental)
[0150] Roll Stitching
[0151] PIV-like image calibration
[0152] SNR, MTF, Geometric correction, gray scale linearity.
[0153] Moving finger method of sensor loading for two point
(loaded, unloaded) gain and offset calibration.
[0154] Applications
[0155] FEDS--Falcon Engineering Development System: basic
engineering tool for testing all STS-xxxx products.
[0156] STARS--Diagnostic tool for STARS production.
[0157] Sonagnose--Diagnostic tool for sensor evaluation.
[0158] GIGO--SPI to USB converter.
[0159] MAPS--Matcher performance testing (EER).
[0160] Customer Demo Codes--used by marketing.
[0161] SonicLib and demo codes have been ported to:
[0162] Windows XP, Vista, 7
[0163] Windows CE (mobile)
[0164] Qualcomm
[0165] Symbian
[0166] Linux
[0167] Android
[0168] Non-OS ports to various ARM chips (NXP, Samsung, ST, Atmel,
TI) and 8051)
MTF Enhancement and Noise-Reduction features--(software algorithms
and state-machine logic) to be Implemented into the ASIC
[0169] 41 Real-time Programmable Look-up table (SLUT)
[0170] 42 Several preprogrammed SLUTS with the ability to use a
predefined sequence of SLUTS to capture several images and
combine.
[0171] 43 Real-time adaptable look-up tables (SLUT) based on
fingerprint grayscale (z-axis) and frequency-domain analysis (with
finger on the sensor).
[0172] 44 Real-time Programmable Tx amplitude envelope over time.
(Used to normalize pixel excitation for individual Tx lines or Tx
groups.)
[0173] 45 Real-time programmable Rx Tx time-delay templates--they
can be programmed to change as 1 image is captured, or for several
image sequences, which would then be combined during
post-processing.
[0174] 46 Real-time programmable "differential" templates--any
grouping of SLUTS, programmable Tx amplitude, and register-settings
creates a template. Several templates are sequenced to produce
several temporary images which are then "differentiated" to extract
the high-quality final image.
[0175] 47 Programmable PLL templates (might include SLUTS and
register settings). May require several PLL templates, slightly
varying off-resonance. Used to analyze the sensor before the finger
touches the sensor. The individual pixel response to varying PLL
frequency is used to predict/calibrate each pixel's sensitivity.
(An off-resonance PLL was used successfully to enhance our original
Tiger sensor's MTF.)
[0176] 48 Any combinations of the above that may normalize pixel
excitation across the sensor image to improve MTF.
[0177] 49 Any combinations of the above that may positively affect
standing-wave characteristics of the sensor image to improve
MTF.
[0178] 50 Any of the above that can be used to resolve the sensor's
static and temporal noise signature, so that noise reduction can be
applied.
[0179] 51 Any combinations of the above, performed both before and
after the finger touches the sensor, to reduce noise, and enhance
MTF.
ASIC (defined by ASIC specs already sold to customer see also specs
for Maverick, Sidewinder, Goldfinger, Lotus)
[0180] Digital architecture
[0181] Processor
[0182] Memory (ROM, SRAM, 1T-SRAM, OTP RAM)
[0183] Bus architecture
[0184] DMA controller
[0185] Encryption cores (AES, ECC, SHA, HMAC)
[0186] OTP RAM usage for security keys storage
[0187] Standard host interfaces
[0188] SPI/USB/UART/EBI/SDIO/7816
[0189] High security interface (challenge, encryption, key
protocol)
[0190] Random number generator
[0191] External devices interface
[0192] Flash memory
[0193] ROM
[0194] SPI/UART/GPIO
[0195] BOOT timer
[0196] Sensor Controller
[0197] Special sequencing one TX at a time, some RX to minimize
peak power consumption
[0198] Sensor LUT/Scan_Enable_LUT/Pixel Cache location mapping LUT
(MAP_LUT)
[0199] Pattern Generator (test & debug)
[0200] Data-In-Cache Counter
[0201] Analog pipeline programmable delays
[0202] Rx start and end (ROI control)
[0203] Cache Controller
[0204] On board Image Histogram with adjustable levels
[0205] Navigation & Finger-detect LUT
[0206] Time Stamp (tick counter)
[0207] Hardware Assisted pixel/image averaging
[0208] Data Sum and Integer Mean (Hardware assisted)
[0209] Timer based image capture triggers
[0210] Rx/Tx Trigger
[0211] Analog interface to sensor
[0212] TX (amplitude control, filtering etc . . . )
[0213] RX (C2V, filter, Gain & Offset programmable amplifier,
ADC)
[0214] Dynamic Gain/Offset adjustment per pixel/line/region
(CAL_SELECT_LUT).
[0215] Initial Calibration, Static Calibration
[0216] Multiplexing of Rx inputs to share components in the
pipeline
[0217] Multiplexing the Tx outputs
[0218] Adjustable Calibration Capacitor
[0219] Adjustable Impedance Sensor Support Line
[0220] Special blocks list
[0221] Brown out circuit (Power on Reset)
[0222] Temperature monitoring (OTEMP)
[0223] Current monitoring
[0224] ESD metastability and lock-up detection "alive monitor
pin"
[0225] Latchup detection "alive monitor pin" & OTEMP
[0226] RCOSC
[0227] Watchdog, RTOS, General purpose, wake-up timers
[0228] Multiple ASIC support (for larger sensors) [0229]
master/slaves--VULCAN type [0230] inter-processor communication
(multi cores in one ASIC) [0231] inter-processor communication
(multi chips on one PCB) [0232] inter-processor communication
(multi chips across PCBs)
[0233] Power Management (sleep, standby, active, etc . . . )
[0234] New items (will be added to Lotus specification)
[0235] 10 or 12 bits A/D
[0236] Automatic averaging for noise reduction (super sampling)
[0237] Independent gains & offsets per pixel (out of n
possibilities)
[0238] Decoupled gain & offset control
[0239] Redefined RX pipeline architecture
[0240] Pure multiplexing of I/O? (reduced circuitry per I/O)
[0241] Reconfiguring I/Os (TX versus RX)
[0242] Pattern recognition accelerator (matching)
[0243] Matcher algorithm accelerator
[0244] FFT accelerator
[0245] Compression/decimation
[0246] NAV correlation engine
[0247] de-ghosting HW
[0248] Automatic thermal compensation
[0249] Sensor compensation
[0250] Temperature detection
[0251] Fingerprint sensor operation improvements
[0252] 59 Multifrequency Impediography. Use of 2 frequencies, fs
and fp (serial and parallel resonance of the pillar) increases the
dynamic range substantially (e.g. it squares the dynamic range
between ridge and valley). This two frequency method is expanded
into even higher sensitivities if more measurements at several
frequencies between fs and fp as well as above fp and below fs are
utilized predicting the load.
[0253] 60 Wavelet impediography. The frequency dependent electrical
impedance around the pillars resonance frequency has typical shape,
which can be described as a wavelet. If a dampening load is applied
to the pillar the wavelet will change its shape. Using mathematical
relation of wavelet analysis will greatly enhance the dynamic range
of acoustic impediography and hence fingerprinting
[0254] 61 Coded excitation will help detecting current change at an
element measured in case the signal level is corrupted by acoustic
noise resulting from crosstalk and wave propagation. The coding is
detected by cross correlation
[0255] There are multiple patterns available for being employed for
correlation which must be evaluated separately. But those will
follow the same regime and are hereby claimed.
[0256] 62 Frequency shift method. A smaller or larger shift to the
lower frequency of fs is observed when pillars are dampened by
outer loads. This shift is detectable and can be used alone or in
combination with the current response for increased SNR and dynamic
range of acoustic impediography.
[0257] 63 Improving mechanical Q
[0258] Mechanical Q is substantially improved and hence dynamic
range and sensitivity of the impediography method if mechanical
crosstalk between elements is reduced. This can be performed in the
following ways:
[0259] a. via material properties and lamb wave propagation
[0260] b. by means of anisotropic interstitional material
[0261] 64 Touch sensor backing
[0262] a) random bonds
[0263] b) surface roughness
[0264] c) structural nonlinearity
[0265] d) low acoustic impedance (0.5 MRayl) material (e.g. airgel,
hollow glass spheres composites)
[0266] 65 Pressure related transmission into the backing location
where ridges touch the sensor transmission into backing is
increased=>improves damping, higher contrast
[0267] 66. Top sensor matching layer=>improves contrast
[0268] 67 Vital parameter extraction from the finger tip: blood
flow, bone structure, tissue speckle, tissue elasticity (tissue
pressure estimator), heart rate from blood flow
[0269] 68 Various scanning schemes for producing pulse-echo image
information and flow estimates including tissue strain.
[0270] Concepts: Ultrasound finger measurements (bone & vein
structure, pulse rate, etc . . . )
[0271] Proof of Life. Scan multiple fingers at the same time with
multiple sensors/ASICs.
[0272] Harvest electrical energy using the piezoelectric properties
of the sensor.
[0273] 69. Detecting finger tip temperature via change of resonance
frequency
[0274] 70. Avoiding unwanted wave propagation across the
fingerprint sensor.
[0275] During operation several transmit lines will be used to
speed up data acquisition. If the location of the lines are chosen
in a way that emitted waves from the transmit lines propagating
across the sensor do not interfere positively on locations
currently measured interference noise is minimized increasing SNR.
This condition is realized if the distance from locations currently
measured to the drive lines are not multiple of the wavelength of
the travelling waves i.e. surface waves, shear and bending
waves.
[0276] Current 1-3 composite of falcon geometry pitch 72 um, width
50 um and pillar height 150 um is approx 50 percent as measured
with laser vibrometry and predicted by FEM modeling. Crosstalk is
reduced, if the interstitional material exhibits a large difference
(preferably a lower) to the pzt, e.g. air. However air will not
keep the pillar in place. Currently Epotek 301-2 is deployed
providing sufficient bonding strength to keep the pillars in place
during grinding the process step exerting the largest force to the
pillar during manufacturing. However, material with much lower
acoustic impedance could be employed as for example epoxy fill with
hollow glass spheres having a diameter of <1 um.
[0277] Another possibility are nano porous polymers currently under
development, but with no known source of commercial production.
[0278] Problem. Air backing is of advantage for ultrasound
transducers as it increases the output amplitude by 30% according
to the Redwood Transient Model. For the fingerprint sensor air
backing is vital, as energy shall be transmitted in the front
medium only. In both cases the sensors front propagation material
is soft tissue a suitable backing must have much lower acoustic
impedance approximately 0.1 MRayl as estimated from earlier
calculations..sup.2 .sup.2 Hard backing would be a solution too.
However the hardest material, pure tungsten, has an ac. Impedance
of 100 MRay leaving us with reflection coefficient of
.about.0.74.
[0279] Particularly for the fingerprint touch sensor the backing is
required for stability.
[0280] Proposed solution. the surface roughness of most material
provides an interface to the fingerprint sensor, which is only
partial in contact with the active sensor. Typically no acoustic
contact is achieved without high static pressure. The reduced
contact area of a rough surface is equivalent to an air like
backing and can support the sensor.
[0281] Backing is provided by a layer sprinkled randomly with bumps
having diameter less than a pillars width. These bumps provide the
support for the sensor. Due to their round shape and small total
area the transmission into the backing is kept low. The average
distance between bumps will be chosen according the bending
strength of the 1-3 piezo composite. For fingerprinting each bump
may create a pillar failing reflecting the front loads. However, if
the fingerprint is over sampled, filtering out those locations will
not degrade the final result of the fingerprint matching schemes.
The random scheme is used to destroy phase coherence for any
transmission and wave propagation in the backing
[0282] A prototype assembly manufacturing plan should be prepared
before a full manufacturing stage. Basically I believe that major
equipment investment can be done after one secure the certain
amount of POs from customers. Meantime, having the prototyping
capability to meet marketing needs is needed with minimum amount of
investment.
[0283] Again, it is preferred that the test-bonding the 3050 sensor
and bezel using the
[0284] MicroPack's 130 Dual Head US bonder be used, whether the US
bonding can be successfully done on the 3050 sensor plus bezel
prototype assembly.
[0285] Sensor FEM Model evaluating sensor performance properties
for fingerprinting using impediography: The model is parametric,
i.e. all geometries can be varied accommodating different pitches
and in turn sensor resolution.
CONCLUSION
[0286] It is to be appreciated that the Detailed Description
section, and not the Summary and Abstract sections, is intended to
be used to interpret the claims. The Summary and Abstract sections
may set forth one or more but not all exemplary embodiments of the
present invention as contemplated by the inventor(s), and thus, are
not intended to limit the present invention and the appended claims
in any way.
* * * * *