U.S. patent application number 17/239151 was filed with the patent office on 2021-08-05 for pixel design for electronic display devices.
The applicant listed for this patent is Apple Inc.. Invention is credited to Giovanni Gozzini, Mohammad Yeke Yazdandoost.
Application Number | 20210240026 17/239151 |
Document ID | / |
Family ID | 1000005539427 |
Filed Date | 2021-08-05 |
United States Patent
Application |
20210240026 |
Kind Code |
A1 |
Yeke Yazdandoost; Mohammad ;
et al. |
August 5, 2021 |
Pixel Design for Electronic Display Devices
Abstract
Systems and methods for through-display imaging. A display
includes an imaging aperture defined through an opaque backing. An
optical imaging array is aligned with the aperture. Above the
aperture, the display is arranged and/or configured for increased
optical transmittance. For example, a region of the display above,
or adjacent to, the imaging aperture can be formed with a lower
pixel density than other regions of the display, thereby increasing
inter-pixel distance (e.g., pitch) and increasing an area through
which light can traverse the display to reach the optical imaging
array.
Inventors: |
Yeke Yazdandoost; Mohammad;
(Santa Clara, CA) ; Gozzini; Giovanni; (Berkeley,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
|
|
Family ID: |
1000005539427 |
Appl. No.: |
17/239151 |
Filed: |
April 23, 2021 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15949681 |
Apr 10, 2018 |
|
|
|
17239151 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F 1/13318 20130101;
H01L 27/3234 20130101; H01L 27/3216 20130101; H01L 51/524 20130101;
H01L 51/5284 20130101; G02F 1/13338 20130101; H01L 51/5271
20130101; G06F 1/1643 20130101; G06K 9/0004 20130101; G06F 3/0412
20130101; G06F 3/042 20130101; H01L 27/323 20130101; H01L 51/5253
20130101; H01L 27/3211 20130101; H01L 51/5275 20130101; H01L
27/3276 20130101; H01L 27/3227 20130101 |
International
Class: |
G02F 1/1333 20060101
G02F001/1333; G06F 3/041 20060101 G06F003/041; G06F 3/042 20060101
G06F003/042; H01L 51/52 20060101 H01L051/52; H01L 27/32 20060101
H01L027/32; G06K 9/00 20060101 G06K009/00; G02F 1/133 20060101
G02F001/133 |
Claims
1. A mobile device comprising: a display having a plurality of
light emitting pixels distributed over a display area, the display
area having, a first pixel region having a first pixel density, the
first pixel density associated with a first number of the light
emitting pixels per unit area; and a second pixel region that is
separate from the first pixel region and has a second pixel
density, the second pixel density associated with a second number
of the light emitting pixels per the unit area; wherein, the first
number of light emitting pixels is different than the second number
of light emitting pixels.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/949,681, filed Apr. 10, 2018, and entitled
"Electronic Device Display for Through-Display Imaging," the
contents of which are incorporated herein by reference as if fully
disclosed herein.
FIELD
[0002] Embodiments described herein relate to electronic device
displays and, in particular, to display stack constructions
defining imaging apertures through opaque layers and promoting
increased inter-pixel optical transmittance to facilitate
through-display imaging.
BACKGROUND
[0003] An electronic device display (a "display") is typically
formed from a stack of functional and structural layers (a "display
stack") that is attached to, or otherwise disposed below, a
protective cover. In many conventional implementations, the
protective cover defines an exterior surface of a housing of an
electronic device that incorporates the display. For increased
contrast, a conventional display stack is intentionally designed to
be opaque.
[0004] An electronic device can also include an imaging sensor,
such as a camera or an ambient light sensor. Typically, an imaging
sensor is positioned below the protective cover, adjacent to the
display stack. As such, a conventional electronic device
incorporating both a display stack and an imaging sensor typically
requires a large-area protective cover that extends beyond the
periphery of the display stack in order to reserve space to
accommodate the imaging sensor. This conventional construction
undesirably increases the apparent size of a bezel region
circumscribing the display, while also undesirably increasing the
size and volume of the housing of the electronic device.
SUMMARY
[0005] Embodiments described herein generally reference electronic
devices including a display stack that forms a display. The display
defines an active display area that, in turn, defines at least two
discrete pixel regions: a first pixel region and a second pixel
region. In many embodiments, the first pixel region has a first
pixel density and the second pixel region has a second pixel
density. The second pixel region can be entirely inset within the
first pixel region, but this may not be required. The second pixel
density is typically less than the first pixel density, but this
may not be required. In one example, the second pixel density is a
factor of two lower than the first pixel density.
[0006] The display stack also includes a backing that is typically
opaque. The opaque backing is positioned below the display and
defines an aperture below the second pixel region. In some cases,
the aperture can be filled with an optically-transparent material
such as an optically clear adhesive. In some examples, the
optically-transparent material has a refractive index approximately
equivalent to one or more layers of the display stack.
[0007] The display also includes an optical imaging array
positioned below the aperture. The optical imaging array is
configured to receive light transmitted through one or more
inter-pixel sub-regions of the second pixel region. An inter-pixel
region is typically defined between at least two pixels (e.g., two
or more pixels).
[0008] In some embodiments, the optical imaging array is configured
to receive light emitted from the display that is subsequently
reflected from a touch input provided above the second pixel
region. Data received from each imaging sensor of the optical
imaging array can be aggregated into an image or sequence of images
that corresponds to surface features of the object or objects
providing the touch input. In an example embodiment, the image(s)
can be used to obtain a fingerprint image of a user touching the
display. In another example embodiment, the image(s) can be used to
detect a touch or force input to the display. In yet another
example embodiment, the image(s) can be used to detect one or more
biometric characteristics that change over time, such as a heart
rate or a respiration rate of a user. The image(s)--or portions
thereof--can be used for any suitable imaging or data aggregation
purpose.
[0009] Other embodiments described herein generally reference
another electronic device including a display stack that forms a
display. In this embodiment, the display defines an active display
area that, in turn, defines at least two discrete pixel regions: a
first pixel region and a second pixel region. In these embodiments,
the first pixel region and the second pixel region have different
optical transmittance; typically the second pixel region has a
higher optical transmittance than the first pixel region. As with
other embodiments, an optical imaging array can be positioned
behind the second pixel region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Reference will now be made to representative embodiments
illustrated in the accompanying figures. It should be understood
that the following descriptions are not intended to limit this
disclosure to one included embodiment. To the contrary, the
disclosure provided herein is intended to cover alternatives,
modifications, and equivalents as may be included within the spirit
and scope of the described embodiments, and as defined by the
appended claims.
[0011] FIG. 1A depicts an electronic device that can incorporate a
display stack suitable for through-display imaging.
[0012] FIG. 1B depicts a simplified block diagram of the electronic
device of FIG. 1A.
[0013] FIG. 2A depicts an example cross-section of the display
stack of FIG. 1A, taken through line A-A, depicting an optical
imaging array positioned below, and aligned with, an imaging
aperture defined through an opaque backing of the display
stack.
[0014] FIG. 2B depicts another example cross-section of the display
stack of FIG. 1A, depicting an optical imaging array and lens
structure positioned below, and aligned with, an imaging aperture
defined through an opaque backing of the display stack.
[0015] FIG. 2C depicts another example cross-section of the display
stack of FIG. 1A, depicting an optical imaging array positioned
below a pinhole aperture defined through an opaque backing of the
display stack.
[0016] FIG. 2D depicts another example cross-section of the display
stack of FIG. 1A, depicting angled illumination of an optical
imaging array positioned below an imaging aperture defined through
an opaque backing of the display stack.
[0017] FIG. 2E depicts another example cross-section of the display
stack of FIG. 1A, depicting an organic light-emitting diode array
that may be operated as a self-illuminating optical imaging
array.
[0018] FIG. 2F depicts another example cross-section of the display
stack of FIG. 1A, depicting an optical imaging array encapsulated
within a light-emitting layer of the display stack.
[0019] FIG. 2G depicts an enlarged detail view of the example
cross-section of the display stack of FIG. 2F, enclosed within the
circle B-B.
[0020] FIG. 3 depicts an example cross-section of a display stack,
such as described herein, depicting an optical imaging array
positioned below a region of reduced pixel density.
[0021] FIG. 4A depicts an example arrangement of pixels of a
display stack defining a region of reduced pixel density resulting
in locally-increased inter-pixel transmittance.
[0022] FIG. 4B depicts another example arrangement of pixels of a
display stack resulting in locally-increased inter-pixel
transmittance.
[0023] FIG. 4C depicts another example arrangement of pixels of a
display stack resulting in locally-increased inter-pixel
transmittance.
[0024] FIG. 5A depicts an example arrangement of subpixels of a
display stack defining a region of reduced pixel density resulting
in locally-increased inter-pixel transmittance.
[0025] FIG. 5B depicts another example arrangement of subpixels of
a display stack defining a region of reduced pixel density
resulting in locally-increased inter-pixel transmittance.
[0026] FIG. 5C depicts another example arrangement of subpixels of
a display stack defining a region of reduced pixel density
resulting in locally-increased inter-pixel transmittance.
[0027] FIG. 5D depicts an example arrangement of subpixel drive
lines of a display stack defining a region of increased inter-pixel
transmittance.
[0028] FIG. 6A depicts an electronic device incorporating a display
stack with a locally-increased inter-pixel transmittance.
[0029] FIG. 6B depicts another electronic device incorporating a
display stack with a locally-increased inter-pixel
transmittance.
[0030] FIG. 6C depicts another electronic device incorporating a
display stack with a locally-increased inter-pixel
transmittance.
[0031] FIG. 6D depicts an enlarged detail view of the electronic
device of FIG. 6C, enclosed within the circle C-C.
[0032] FIG. 7 is a simplified flow chart depicting example
operations of a method of capturing an image of an object touching
a display, such as described herein.
[0033] FIG. 8 is a simplified flow chart depicting example
operations of a method of capturing an image of an object touching
a display, such as described herein.
[0034] The use of the same or similar reference numerals in
different figures indicates similar, related, or identical
items.
[0035] The use of cross-hatching or shading in the accompanying
figures is generally provided to clarify the boundaries between
adjacent elements and also to facilitate legibility of the figures.
Accordingly, neither the presence nor the absence of cross-hatching
or shading conveys or indicates any preference or requirement for
particular materials, material properties, element proportions,
element dimensions, commonalities of similarly illustrated
elements, or any other characteristic, attribute, or property for
any element illustrated in the accompanying figures.
[0036] Additionally, it should be understood that the proportions
and dimensions (either relative or absolute) of the various
features and elements (and collections and groupings thereof) and
the boundaries, separations, and positional relationships presented
therebetween, are provided in the accompanying figures merely to
facilitate an understanding of the various embodiments described
herein and, accordingly, may not necessarily be presented or
illustrated to scale, and are not intended to indicate any
preference or requirement for an illustrated embodiment to the
exclusion of embodiments described with reference thereto.
DETAILED DESCRIPTION
[0037] Embodiments described herein reference an electronic device
that includes a display and an imaging sensor positioned behind the
display. The display is constructed from a number of structural and
functional layers collectively referred to as a "display stack."
The imaging sensor can be any suitable imaging sensor, including
both single-element imaging sensors (e.g., photodiodes,
phototransistors, photosensitive elements, and so on) and
multi-element imaging sensors (e.g., complementary metal oxide
semiconductor arrays, photodiode arrays, and so on). For convenient
reference, imaging sensors--however constructed or implemented--are
referred to herein as "optical imaging arrays."
[0038] In many embodiments, an optical imaging array is positioned
behind a display and is oriented to receive light transmitted
through the display in a direction generally opposite that of light
emitted from the display. The optical imaging array can be used by
the electronic device for any suitable imaging, sensing, or data
aggregation purpose including, but not limited to: ambient light
sensing; proximity sensing; depth sensing; receiving structured
light; optical communication; proximity sensing; biometric imaging
(e.g., fingerprint imaging, iris imaging, facial recognition, and
so on); and the like.
[0039] A display such as described herein can be associated with
multiple discrete optical imaging arrays, distributed behind
different regions of the display and/or configured for different
purposes or in different ways, but for simplicity of description,
many embodiments that follow reference a construction in which a
single optical imaging array is positioned behind an active display
area of a display of an electronic device. The embodiments
described herein may be altered or adjusted to incorporate discreet
optical imaging arrays in a variety of locations relative to a
display or non-display surface of an electronic device.
[0040] In many embodiments, the optical imaging array is aligned
with and optically coupled to an imaging aperture defined through
one or more opaque or substantially opaque layers of the display
stack such as, but not limited to: backing layers; support layers;
reflector layers; backlights; and so on. As a result of this
construction, light directed toward the display can pass through an
imaging aperture and can be received and quantified by the optical
imaging array.
[0041] Some embodiments described herein reference systems,
architectures, constructions, techniques, and methods for
increasing transmissivity of light (e.g., reducing absorption,
reflection, refraction, diffraction, and/or diffusion) through the
imaging aperture. In other cases, the imaging aperture can be
positioned relative to, or otherwise associated with, one or more
thinned portions of a display stack. These constructions increase
the quantity of light received by the optical imaging array and,
therefore, increase the quality, resolution, and/or signal-to-noise
ratio of images or data generated by the optical imaging array.
[0042] Embodiments configured to increase transmissivity through a
display stack include operations, techniques, and constructions
such as, but not limited to: locally reducing pixel density of a
display stack above an imaging aperture; locally altering a pixel
or subpixel distribution pattern or arrangement above an imaging
aperture; locally altering an electronic trace distribution (e.g.,
a thin-film transistor layer) or path above an imaging aperture;
filtering light passing through an imaging aperture (e.g.,
collimating filters, infrared cut filters, narrow filed filters,
polarizing filters, and so on); refracting or reflecting light
passing through an imaging aperture (e.g., micro or macro lenses,
beam-shaping, beam directing, and so on); and so on, or
combinations thereof.
[0043] As a result of these and other constructions described
herein, an optical imaging array positioned below an imaging
aperture defined by a display stack can capture high-quality and
high-resolution image data through a display of an electronic
device while the display of that electronic device is generating
one or more images. This technique is generally referred to herein
as "through-display imaging." In these embodiments, the display of
the electronic device appears to a user as a conventional display;
no visual, tactile, or other indication of an optical imaging array
is readily observed by a user of the electronic device.
[0044] As noted above, an electronic device can implement
through-display imaging for any suitable imaging, sensing, data
aggregation, or light capture purpose including, but not limited
to: ambient light detection; ambient color temperature detection;
picture or image capture; biometric imaging (e.g., fingerprint
imaging, iris imaging, face recognition, and so on); optical
device-to-device or network communication; receiving structure
light reflections or transmissions; depth estimation or mapping;
proximity sensing; touch sensing; and so on.
[0045] For simplicity of description, many embodiments that follow
reference a construction in which an electronic device implements
through-display imaging to capture one or more images of a
fingerprint of a user touching a specified region (an "imaging
region," above an imaging aperture) of the display of the
electronic device, but this is not required of all embodiments.
Through-display imaging can be implemented for any other purpose
(or multiple purposes) described herein in any embodiment or
implementation discussed herein. Multiple imaging regions (of the
same or different size, shape, or imaging purpose) can be defined
by a display or, alternatively, a single imaging region can be
defined. In other cases, an entire display may be capable of
through-display imaging.
[0046] These foregoing and other embodiments are discussed below
with reference to FIGS. 1A-8. However, those skilled in the art
will readily appreciate that the detailed description given herein
with respect to these figures is for explanatory purposes only and
should not be construed as limiting.
[0047] FIG. 1A depicts an electronic device 100, including a
housing 102 that encloses a display stack defining a display. The
display stack can include layers or elements such as, in no
particular order: a touch input layer; a force input layer; an
anode layer; a cathode layer; an organic layer; an encapsulation
layer; a reflector layer; a stiffening layer; an injection layer; a
transport layer; a polarizer layer; an anti-reflective layer; a
liquid crystal layer; a backlight layer; one or more adhesive
layers; a compressible layer; an ink layer; a mask layer; and so
on.
[0048] For simplicity of description, the embodiments that follow
reference an organic light-emitting diode display stack including,
among other layers: a reflective backing layer; a thin-film
transistor layer; an encapsulation layer; and an emitting layer. It
is appreciated, however, that this is merely one illustrative
example implementation and that other displays can be implemented
with other display technologies, or combinations thereof.
[0049] The display stack also typically includes an input sensor
(such as a force input sensor and/or a touch input sensor) to
detect one or more characteristics of a user's physical interaction
with an active display area 104 of the display of the electronic
device 100. The active display area 104 is typically characterized
by an arrangement of individually-controllable,
physically-separated, and addressable pixels or subpixels
distributed at one or more pixel densities. Example input
characteristics that can be detected by an input sensor include,
but are not limited to: touch location; force input location; touch
gesture path, length, duration, and/or shape; force gesture path,
length, duration and/or shape; magnitude of force input; number of
simultaneous force inputs; number of simultaneous touch inputs; and
so on. As a result of this construction, a user 106 of the
electronic device 100 is encouraged to interact with content shown
in the active display area 104 by physically touching and/or
applying a force to the input surface above the active display area
104.
[0050] In these embodiments, the display stack is additionally
configured to facilitate through-display imaging of the user's
fingerprint when the user 106 touches the display to interact with
content shown in the active display area 104.
[0051] More specifically, in one example, the display stack defines
an imaging aperture (not shown) through a reflective backing layer
of the display stack, thereby permitting light to travel through
the display stack between two or more organic light-emitting diode
subpixels or pixels (herein, "inter-pixel" regions). In some cases,
the imaging aperture takes a rectangular shape and is disposed on a
lower region of the active display area 104. In other cases, the
imaging aperture takes a circular or oval shape and is disposed in
a central region of the active display area 104. Typically, the
imaging aperture is larger than the fingerprint of the user 106,
but this may not be required and smaller apertures may be
suitable.
[0052] As noted with respect to other embodiments described herein,
the electronic device 100 also includes an optical imaging array
(not shown). The optical imaging array is positioned below the
imaging aperture in order to collect and quantify light directed
through the inter-pixel regions of the display stack. As a result
of this construction, the electronic device 100 can obtain an image
of the fingerprint of the user 106; this operation is referred to
herein as a "fingerprint imaging operation."
[0053] In some embodiments, the display of the electronic device
100 illuminates the finger of the user 106 during a fingerprint
imaging operation. For example, in some embodiments, the display of
the electronic device 100 illuminates a region of the display below
the user's finger, as detected by the input sensor. In other
examples, the display illuminates a perimeter of the user's finger.
In some examples, the display of the electronic device 100
illuminates discrete portions of the user's finger in sequence or
in a particular pattern.
[0054] Illumination of the user's finger during a fingerprint
imaging operation can occur in a number of suitable ways. For
example, in some cases, the display of the electronic device 100
illuminates the user's finger with pulsed (continuous or discrete)
or steady white light. In another example, the display of the
electronic device 100 illuminates the user's finger with pulsed or
steady blue or green light. In some examples, the display of the
electronic device 100 illuminates the user's finger with light
emitted with a particular modulation pattern or frequency. In some
examples, the display of the electronic device 100 illuminates the
user's finger by alternating between blue and green light at a
particular frequency, modulation, pulse pattern, waveform and so
on; red light illumination may be due to undesirable subsurface
scattering of red light in the user's finger. In still other
examples, the display of the electronic device 100 illuminates the
users finger with a portion of a contiguous image shown on the
entire display. In other words, the portion(s) of the display below
the user's fingerprint may not be specially or differently
illuminated from other portions of the display; the display can
continue to render whichever static or animated image or series of
images appeared on the display prior to the user touching the
display. In still further examples, the display of the electronic
device can locally increase brightness below the user's finger, can
locally increase contrast below the user's finger, can locally
increase saturation below the user's finger, and so on.
[0055] In some embodiments, the user's finger can be illuminated
during a fingerprint imaging operation in another manner. For
example, in some cases, a side-firing illuminator can be integrated
into the display stack. In a side-firing illumination operation,
portions of the user's fingerprint in contact with the imaging
surface (e.g., ridges of the fingerprint) can diffuse and/or
reflect light emitted from the side-firing illuminator. Other light
emitted from the illuminator is reflected away from the optical
imaging array as a result of total internal reflection.
[0056] It may be appreciated that the foregoing description of FIG.
1A, and the various alternatives thereof and variations thereto are
presented, generally, for purposes of explanation, and to
facilitate a thorough understanding of various possible
configurations of an electronic device incorporating a display
stack suitable for through-display imaging, such as described
herein. However, it will be apparent to one skilled in the art that
some of the specific details presented herein may not be required
in order to practice a particular described embodiment, or an
equivalent thereof. For simplicity of description and illustration,
FIG. 1B is provided. This figure depicts a simplified block diagram
of the electronic device of FIG. 1A showing various operational and
structural components that can be included in an electronic device
configured to through-display imaging such as described herein.
[0057] In particular, the electronic device 100 includes an outer
protective cover 108. The protective outer cover 108 defines an
input surface for the user 106 and, additionally, protects and
encloses various components of the electronic device 100. The
protective outer cover 108 can be made from any number of suitable
materials, whether transparent, translucent, or opaque, including,
but not limited to, glass, plastic, acrylic, polymer materials,
organic materials, and so on.
[0058] The electronic device 100 also includes an input sensor 110
disposed below the protective cover 108. The input sensor 110 can
be any suitable input sensor including, but not limited to: a
capacitive input sensor; a resistive input sensor; an inductive
input sensor; an optical input sensor; and so on. The input sensor
110 can be configured to detect any suitable user input or
combination of user inputs including, but not limited to: touch
gestures; touch inputs; multi-touch inputs; force inputs; force
gestures; multi-force inputs; pressure inputs; thermal inputs;
acoustic inputs; and so on.
[0059] The electronic device 100 also includes a display stack 112
which can be disposed below the input sensor 110. The display stack
112 can be formed from a number of independent layers of material
or materials that cooperate to define the active display area 104
(see, e.g., FIG. 1A). In many examples, the display stack 112
defines an organic light emitting diode display, but this may not
be required. For example, in other cases, the display stack 112 can
define, without limitation: a micro light emitting diode display; a
liquid crystal display; an electronic ink display; a quantum dot
display; and so on. As noted with respect to other embodiments
described herein, the display stack 112 can define an array of
discrete pixels that are independently addressable and
controllable. The pixels of the display stack 112 can be disposed
at a constant pitch or a variable pitch to define a single pixel
density or one or more pixel densities.
[0060] As noted with respect to other embodiments described herein,
a low pixel density region of the active display area 104 of the
display stack 112 is positioned above an optical imaging array 114
such that the optical imaging array 114 can receive light
transmitted through the inter-pixel regions of the low pixel
density region of the active display area 104 of the display stack
112.
[0061] The optical imaging array 114 can be any suitable optical
imaging array including one or more photosensitive elements
arranged in any suitable pattern. In many examples, the optical
imaging array 114 is a low fill-factor array of phototransistor or
photodiode elements, but this may not be required of all
embodiments.
[0062] The optical imaging array 114, the display stack 112, and
the input sensor 110--among other elements, modules, or components
of the electronic device 100--are communicably coupled to a
processor 116. The processor 116 can be any suitable processor or
circuitry capable of performing, monitoring, or coordinating one or
more processes or operations of the electronic device 100. The
processor 116 can be any suitable single-core or multi-core
processor capable to execute instructions stored in a memory (not
shown) to instantiate one or more classes or objects configured to
interface with an input or output of one or more of the optical
imaging array 114, the display stack 112, and/or the input sensor
110. In some examples, the processor 116 may be a dedicated
processor associated with one or more of the optical imaging array
114, the display stack 112, and/or the input sensor 110. In other
cases, the processor 116 may be a general purpose processor.
[0063] In still other embodiments, the electronic device 100 can
include one or more optional optical components 118. The optional
optical components 118 are typically positioned between the optical
imaging array 114 and the display stack and can include, but may
not be limited to: one or more lenses, filters, mirrors, actuators,
apertures, irises, flash elements, flood illuminators, or other
accessory optical elements, or combinations thereof.
[0064] In many examples, the electronic device 100 also includes an
imaging aperture 120 defined into or through one or more layers of
the display stack 112. The imaging aperture 120 is typically
aligned with one or more low pixel density regions of the active
display area 104 of the display stack 112 and, additionally aligned
with the optical imaging array 114. As noted with respect to other
embodiments described herein, the imaging aperture 120 can take any
suitable size or shape.
[0065] Accordingly, generally and broadly in view of FIGS. 1A-1B,
it is understood that an electronic device including a display
suitable for through-display imaging can be configured in a number
of ways. For example, although the electronic device 100 is
depicted as a cellular phone, it may be appreciated that other
electronic devices can incorporate a display stack such as
described herein including, but not limited to: tablet devices;
laptop devices; desktop computers; computing accessories;
peripheral input devices; vehicle control devices; mobile
entertainment devices; augmented reality devices; virtual reality
devices; industrial control devices; digital wallet devices; home
security devices; business security devices; wearable devices;
health devices; implantable devices; clothing devices; fashion
accessory devices; and so on.
[0066] Further it is appreciated that the electronic device can
also include a processor, memory, power supply and/or battery,
network connections, sensors, input/output ports, acoustic
elements, haptic elements, digital and/or analog circuits for
performing and/or coordinating tasks of the electronic device 100,
and so on. For simplicity of illustration, the electronic device
100 is depicted in FIG. 1A without many of these elements, each of
which may be included, partially and/or entirely, within the
housing 102 and may be operationally or functionally associated
with, or coupled to, the display of the electronic device 100.
[0067] Further, although the electronic device 100 includes only a
single rectangular display, it may be appreciated that this example
is not exhaustive. In other embodiments, an electronic device can
include, or may be communicably coupled to, multiple displays, one
or more of which may be suitable for through-display imaging. Such
accessory/auxiliary displays can include, but may not be limited
to: secondary monitors; function row or keyboard key displays;
wearable electronic device displays; peripheral input devices
(e.g., trackpads, mice, keyboards, and so on) incorporating
displays; digital wallet screens; and so on. Similarly, a
rectangular display may not be required; other embodiments are
implemented with displays taking other shapes, including
three-dimensional shapes (e.g., curved displays).
[0068] Similarly, although the display described in reference to
the electronic device 100 is a primary display of an electronic
device, it is appreciated that this example is not exhaustive. In
some embodiments, a display stack can define a low-resolution
auxiliary display, such as a monochromatic display or a greyscale
display. In other cases, a display stack can define a single-image
display, such as a glyph or icon. In one specific example, a power
button for an electronic device can include a button cap
incorporating a display such as described herein. The display can
be configured to selectively display a power icon and/or a limited
set of icons or glyphs associated with one or more functions the
button may be configured to perform, or one or more configurable
options the button is associated with (e.g., power options, standby
options, volume options, authentication options, digital purchase
options, user authentication options, and so on). In these
examples, a limited-purpose, auxiliary, or secondary display can be
configured to have partial transparency or translucency, such as
described herein, to facilitate through-display imaging.
[0069] Thus, it is understood that the foregoing descriptions of
specific embodiments are presented for the purposes of illustration
and description. These descriptions are not exhaustive nor intended
to limit the disclosure to the precise forms recited herein. To the
contrary, it will be apparent to one of ordinary skill in the art
that many modifications and variations are possible in view of the
above teachings. Particularly, it is understood that a display
stack suitable for through-display imaging can be constructed
and/or assembled in many suitable ways. For example, many
embodiments described herein reference methods, constructions, and
architectures that promote increased optical transmissivity through
the display stack above an imaging aperture.
[0070] For example, a display stack such as described herein can
include one or more regions having reduced pixel density relative
to other regions. A reduced pixel density is typically associated
with increased optical transmittance between pixels because the
inter-pixel area through which light can traverse the display stack
increases. In one implementation of this example, a circular region
having a low pixel density (and therefore increased inter-pixel
optical transmittance) can be inset within a rectangular region
having a higher pixel density (and therefore lower inter-pixel
optical transmittance). (see, e.g., FIG. 6A, discussed in greater
detail below). In this example, the second region can be entirely
inset within the first region, although this is not required. In a
more specific example, a circular or oval region (in one example,
generally the size and/or shape of a user's finger) can be inset
within a rectangular region. In another example, a rectangular
region can be inset within a larger rectangular region. (see, e.g.,
FIG. 6B, discussed in greater detail below). In another example, a
square or rectangular region having a low pixel density can be
positioned along one edge of another square or rectangular region
having a higher pixel density. (see, e.g., FIGS. 6C-6D, discussed
in greater detail below).
[0071] In yet another example, a rectangular region can surround
two or more shaped regions taking any regular, repeating,
symmetrical, asymmetrical, or arbitrary shape. In yet another
example, a display stack can define a boundary region that has
increased optical transmittance relative to a central region. The
boundary can be continuous or discontinuous. In an alternate
example, a display stack can define a central region that has
increased optical transmittance relative to a boundary or perimeter
region that is either continuous or discontinuous. In another
example, a display stack can define a grid of regions in which
alternating regions of the grid have differing optical
transmittance. It may be appreciated that the examples above are
not exhaustive; any suitable layout or distribution of regions of
differing optical transmittance is possible.
[0072] Independent of a particular selected implementation, it is
understood that reduced pixel density regions can be formed and/or
defined in a number of suitable ways, some of which are described
below in reference to FIG. 3. For example, in some cases, a display
stack can be manufactured with a single pixel density, after which
a subset of pixels in a selection region of the display stack can
be removed (e.g., via etching, ablation, mechanical abrasion, and
so on). In these embodiments, the reduced-density region can be
formed, defined, or disposed in such a manner such that the lower
pixel density is not readily apparent when viewed from a typical
distance by an average user. For example, a reduced-density region
may be formed from pixels of greater size and/or brightness, or in
a different shape, such that the display stack appears to present a
display of uniform resolution, brightness, contrast, and/or picture
quality despite that pixel density varies across the area of the
display stack. (see, e.g., FIG. 5C). In one specific example, a
display stack can have a first region with a pixel density between
200-600 pixels per inch (e.g., 450 pixels per inch) and a second
region between 100-300 pixels per inch (e.g., 225 pixels per inch).
In these examples, an optical imaging array can be positioned below
the display stack and aligned with the second region of pixels.
[0073] In some examples, pixel densities of certain regions can be
substantially isotropic or substantially anisotropic. For example,
in some embodiments, a first region can have an isotropic pixel
density, whereas a second region can have the same pixel density as
the first region along a first direction and a second pixel density
along a second direction. In one specific example, a display stack
defining a rectangular display can have a pixel density of
approximately 450 pixels per inch along a length of the display and
of approximately 225 pixels per inch along a width of the display.
In some examples, adjacent anisotropic pixel density regions can be
alternated (e.g., in a grid pattern, adjacent anisotropic pixel
density regions are angularly offset from one another) so as to
obscure the presence or appearance of lower pixel density.
[0074] In some examples, a display stack can define various regions
having different electronic trace layouts than other regions. (see,
e.g., FIG. 5D). As noted with respect to other embodiments
described herein, a low trace density results in increased optical
transmittance through the display stack in that region. For
example, a first region can include traces disposed and/or defined
with a first density whereas a second region can define traces
disposed and/or defined with a second density.
[0075] In some examples, a display stack can define regions having
different patterns of subpixels and/or different subpixel triad
layouts relative to other adjacent regions. (see, e.g., FIGS.
5A-5C). As noted with respect to other embodiments described
herein, expanded subpixel triads can be associated with increased
optical transmittance. (see, e.g., FIGS. 5B-5C). For example, in
one embodiment, a first region can be defined by a diamond-pattern
pixel layout whereas a second region can be defined by columnar
subpixel triads. In another example, a first region is defined by a
first dot pitch whereas a second region is defined by a second dot
pitch. Other pixel layouts and/or subpixel triad layouts are
possible.
[0076] In some examples, a display stack can define regions having
different subpixel colors or arrangements than other regions. More
specifically, a display stack can define regions in which one or
more subpixel colors are omitted or shared between multiple
subpixels. (see, e.g., FIG. 5A). As noted with respect to other
embodiments described herein, partial or incomplete subpixel triads
are typically associated with increased optical transmittance due
to the increased inter-pixel area through which light can traverse
the display stack. In one example, a first region can be defined by
a regular distribution of subpixels into triads of red, green, and
blue whereas a second region can be defined by a distribution of
subpixels of only green and blue. In other cases, adjacent subpixel
pairs (e.g., green and blue) can share a single red subpixel which
may be larger than either subpixels of the green/blue subpixel
pair.
[0077] In some examples, a display stack can include regions
implemented with different display technology than other regions of
the same display stack. For example, a first region can defined by
liquid-crystal technology (generally low transmittance) whereas
another region can be defined by organic light-emitting diode
technology (higher transmittance). Differing display technologies
that can be used together in a single display stack can define, but
may not be limited to: liquid crystal technology; organic
light-emitting diode technology; quantum dot technology; plasma
backlit technology; vertical-cavity surface-emitting laser
technology; projection technology; electronic ink technology; and
so on.
[0078] Certain example implementations of an optical imaging array
positioned behind an imaging aperture defined by a display stack
are depicted in FIGS. 2A-2D. In particular, FIG. 2A depicts an
example cross-section of the display stack of FIG. 1A, touched by a
user, taken through line A-A, depicting an optical imaging array
positioned below an imaging aperture defined through an opaque
backing of the illustrated display stack.
[0079] More specifically, FIG. 2A depicts a through-display imaging
architecture 200a for an organic light-emitting diode display that
facilitates imaging of a fingerprint of a user 202 through a
display stack 204. The display stack 204 in this example includes a
protective outer cover 206, an emitting layer 208 and an opaque
backing layer 210. In other cases, the display stack 204 includes
other layers such as, but not limited to: thin-film transistor
layers; capacitive touch sensing layers; force sensing layers;
backlight layers; polarizer layers; and so on.
[0080] The protective outer cover 206 of the display stack 204 is
typically formed from an optically transparent substrate material
such as glass, acrylic, plastic, or the like. The protective outer
cover 206 defines an input surface that can be touched by the user
202. In many examples, the protective outer cover 206 defines at
least a portion of an exterior surface of a housing of an
electronic device. In other words, the protective outer cover 206
may at least partially enclose and/or seal one or more layers of
the display stack 204, such as the emitting layer 208 or the opaque
backing layer 210.
[0081] The emitting layer 208 of the display stack 204 includes a
number of individual pixels or subpixels, some of which are
identified as pixels P.sub.1-P.sub.4. The pixels of the emitting
layer 208 can be arranged in any suitable pattern. As illustrated,
the pixels of the emitting layer 208 are arranged in a regular
linear pattern, but this may not be required and some pixels may be
arranged closer together or farther apart.
[0082] The opaque backing layer 210 of the display stack 204 can
provide structural support for one or more layers of the display
stack 204, although this is not required. In some cases, the opaque
backing layer 210 is formed from an optically reflective material
whereas in others, the opaque backing layer 210 is formed from an
ink or light-absorbing material.
[0083] The opaque backing layer 210 defines an imaging aperture
212. As noted with respect to other embodiments described herein,
the imaging aperture 212 can be defined to take any suitable size
or shape. In some cases, the imaging aperture 212 is filled with an
optically clear material, such as an optically-clear adhesive. In
further cases, the imaging aperture 212 can extend through
additional opaque, transparent, or translucent layers of a display
stack.
[0084] The through-display imaging architecture 200a also includes
an optical imaging array 214. The optical imaging array 214
includes an array of photosensitive elements 216 positioned below a
narrow field-of-view filter 218. The narrow field-of-view filter
218 filters light received by the array of photosensitive elements
216 such that only light that is substantially normal to the array
of photosensitive elements 216 is received (e.g., as one example,
.+-.10% of ninety degrees measured from a planar surface of the
array of photosensitive elements 216). In other examples, the
narrow field-of-view filter 218 may not be required or
included.
[0085] The array of photosensitive elements 216 of the
through-display imaging architecture 200a can be communicably
coupled to a processor or a processing circuitry (not shown) via a
circuit board 220. The circuit board 220 can be formed from a rigid
or flexible substrate. The processor or processing circuitry can be
a general purpose processor or circuitry or an application-specific
processor or circuitry configured for, in many examples, encrypted
or otherwise secure data processing and/or storage.
[0086] As a result of the depicted construction, an image of the
fingerprint of the user 202 can be obtained by the optical imaging
array 214 through the display stack 204. More specifically, during
a fingerprint imaging operation, one or more pixels of the emitting
layer 208 below or adjacent to the user's fingerprint can be
illuminated (with any suitable modulation, brightness, color or
spectrum, and so on) when the user 202 touches the protective outer
cover 206. Light emitted from the illuminated pixels or subpixels
is directed toward the user's fingerprint and, in turn, is
reflected toward the optical imaging array 214 by the various
features of the user's fingerprint in contact with the protective
outer cover 206 (e.g., the valleys of the user's fingerprint, such
as the valley 202a, reflect a different quantity of light than the
ridges of the user's fingerprint, such as the ridge 202b). A
portion of the reflected light passes through inter-pixel regions
of the emitting layer 208 and through the imaging aperture 212 and
continues toward the optical imaging array 214. In this manner, the
optical imaging array 214 receives reflected light originally
emitted by at least one pixel of the display stack 204.
[0087] As noted above, the narrow field-of-view filter 218
rejects/blocks light that is not substantially normal to the array
of photosensitive elements 216. For example, the rays
u.sub.1-u.sub.5, emitted from the pixels P.sub.1-P.sub.3, can be
captured by the array of photosensitive elements 216 whereas the
rays u.sub.6-u.sub.8, emitted from the pixels P.sub.3-P.sub.4, are
rejected/blocked by the narrow field-of-view filter 218. As a
result of this construction, the array of photosensitive elements
216 can capture an image of the portion of the fingerprint that is
positioned above the imaging aperture 212.
[0088] In many cases, the image of the fingerprint (or the portion
of the fingerprint) can be filtered by a processor or processing
system (not shown) after the image is captured by the array of
photosensitive elements 216. In many embodiments, spatial filtering
can remove aberrations in the image resulting from the physical
structure of the emitting layer 208 and/or other layers of the
display stack 204 (in one non-limiting example, the arrangement of
opaque pixels of the emitting layer 208 may cause an array of dark
spots in the image). An example spatial filtering technique that
may be applied is point-source filtering.
[0089] In this manner, the combination of the opaque backing layer
210, the imaging aperture 212, and the emitting layer 208 cooperate
to define a display suitable for through-display imaging,
identified in the figure as the display 222.
[0090] In some embodiments, an optical imaging sensor can also be
associated with, or positioned relative to, one or more lenses,
filters, mirrors, actuators, apertures, irises, flash elements,
flood illuminators, or other accessory optical elements, or
combinations thereof. Example accessory optical elements that can
be optically coupled and/or associated with one or more optical
imaging sensors--such as the optical imaging array 214 of FIG.
2A--include but are not limited to: micro lenses; macro lenses;
light guides; total-internal reflection interfaces; mirrored
interfaces; digitally-variable mirrors; collimating filters;
polarizing filters; color filters; infrared cut filters;
ultraviolet cut filters; beam-directing lenses; beam-directing
mirror arrays; and so on.
[0091] For example, FIG. 2B depicts another through-display imaging
architecture, identified as the through-display imaging
architecture 200b, for an organic light-emitting diode display that
facilitates imaging of a fingerprint of a user 202 through a
display stack 204. The display stack 204 in this example can be
configured in the same manner as the display stack 204 described in
reference to FIG. 2A; accordingly this description is not
repeated.
[0092] In this embodiment, a lens 224 can be positioned below the
imaging aperture of the display 222 and an image sensor 226. The
image sensor 226 includes an array of photosensitive elements 228
(e.g., complementary metal oxide semiconductors) coupled to a
substrate or circuitry board 230. In this embodiment, light emitted
from the display 222 that reflects from the fingerprint of the user
202 is focused by the lens 224 onto the array of photosensitive
elements 228 of the image sensor 226. Example rays u.sub.9-u.sub.n
are provided corresponding to light emitted from the pixel P.sub.5,
reflected from the user 202, and received at the image sensor
226.
[0093] In some embodiments, a through-display imaging architecture
can include a number of pinhole apertures in place of a single
image aperture. For example, FIG. 2C depicts a through-display
imaging architecture 200c for imaging a fingerprint of a user 202
through a display stack 204. In this example, the display 222
includes a number of pinhole-size imaging apertures, one of which
is shown as formed between the pixels P.sub.1 and P.sub.5. The
various pinhole apertures can each, independently, function as a
pinhole camera (e.g., a camera obscura) positioned to image a
portion of the fingerprint of the user 202.
[0094] Any number or distribution of pinhole imaging apertures can
be used in different embodiments. In one example, an array of
pinhole images apertures is offset from pixels of the display 222
such that each pinhole imaging aperture is positioned below an
inter-pixel region of the display 222. It may be appreciated that
any suitable number of pinhole imaging apertures can be defined in
a number of suitable patterns above an optical imaging array
214.
[0095] As noted above, the embodiments described in reference to
FIGS. 2A-2C typically illuminate the finger of the user 202 by
activating pixels below the user's finger. However, this may not be
required of all embodiments.
[0096] For example, FIG. 2D depicts a through-display imaging
architecture 200d that illuminates the user's fingerprint from a
pixel offset from the imaging aperture. The ray u.sub.15 is shown
originating at pixel P.sub.6, offset from the imaging aperture of
the display 222. As a result of the offset, the fingerprint of the
user 202 is illuminated at an angle. As a result of the angle,
portions of one or more valleys of the user's fingerprint can be
illuminated to a different extent than if the same valley were
illuminated from below. As such, by sequentially changing the pixel
or pixels used to illuminate the fingerprint of the user--and thus
the angle of illumination--the optical imaging array 214 can
capture a series of images of the fingerprint of the user 202.
Variations between different images can be analyzed to determine
three-dimensional characteristics (e.g., depth information) of one
or more valleys of the fingerprint of the user 202.
[0097] It may be appreciated that the foregoing description of
FIGS. 2A-2D, and various alternatives thereof and variations
thereto are presented, generally, for purposes of explanation, and
to facilitate a thorough understanding of various possible
configurations of an optical imaging array positioned behind a
display stack with locally-increased optical transmittance, such as
described herein. However, it will be apparent to one skilled in
the art that some of the specific details presented herein may not
be required in order to practice a particular described embodiment,
or an equivalent thereof.
[0098] Thus, it is understood that the foregoing descriptions of
specific embodiments are presented for the purposes of illustration
and description. These descriptions are not exhaustive nor intended
to limit the disclosure to the precise forms recited herein. To the
contrary, it will be apparent to one of ordinary skill in the art
that many modifications and variations are possible in view of the
above teachings. Particularly, it is understood that large-scale
imaging apertures and/or pinhole apertures (herein, collectively,
"imaging apertures") can be formed in a number of ways through one
or more layers of a display stack.
[0099] For example, in the illustrated embodiments, imaging
apertures are defined through an opaque backing layer of the
display stack. In other embodiments, a pinhole and/or imaging
aperture can be defined through multiple layers of the display
stack, such as, but not limited to: structural layers; polarizer
layers; backlight layers; metal frames; reflector layers; liquid
crystal layers; thin-film transistor layers; organic light-emitting
diode anode or cathode layers; encapsulation layers; ink layers;
and so on.
[0100] Some embodiments include a single imaging aperture, whereas
others include multiple discrete, grouped or patterned imaging
apertures. For example, in one embodiment, an array of pinhole
apertures can be defined through a backing of a display stack. The
array of pinhole apertures can be formed in a regular, tessellated,
symmetric, asymmetric, or irregular pattern and may take any
suitable shape.
[0101] In still other examples, an imaging aperture may not be
required. In these embodiments, an optical imaging array can be
positioned within a display stack. Example implementations of an
optical imaging array positioned within a display stack are
depicted in FIGS. 2E-2G.
[0102] FIG. 2E depicts another example cross-section of the display
stack of FIG. 1A, depicting an organic light-emitting diode array
that may be operated as a self-illuminating optical imaging array.
More specifically, in this embodiment, an organic light-emitting
diode pixel can be used as an optical sensing element. In the
illustrated embodiment, a through-display imaging architecture 200e
can image a fingerprint of a user 202 when the user 202 touches a
protective outer cover of a display stack 204. In this example,
pixel P.sub.7 can be used to illuminate the fingerprint of the user
202. During a fingerprint imaging operation, pixels adjacent to the
pixel P.sub.7 (e.g., pixels P.sub.5 and P.sub.2) are not
illuminated, but instead can be used to receive light reflected
(e.g., u.sub.18-u.sub.19) from the user's finger. It may be
appreciated that any suitable number, pattern, or arrangement of
pixels can be used to illuminate or image the user's finger.
[0103] In yet other embodiments, an optical imaging array can be
integrated into a display stack. FIGS. 2F-2G depict another example
through-display imaging architecture 200f that includes an array of
optical sensing elements disposed between and/or below pixels of an
organic light-emitting diode display. In particular, the
through-display imaging architecture 200f includes an array of
optical sensing elements disposed in inter-pixel regions of the
display 222. Each optical sensing element includes a collimating
filter 232 positioned above a photosensitive element 234. As a
result of this construction, when a pixel of the display emits
light that is reflected by a user's fingerprint, the reflected
light (e.g., u.sub.20-u.sub.21) can be received by the
photosensitive elements and an image of the fingerprint can be
obtained.
[0104] It may be appreciated that the foregoing description of
FIGS. 2E-2G, and various alternatives thereof and variations
thereto are presented, generally, for purposes of explanation, and
to facilitate a thorough understanding of various possible
configurations of an optical imaging array positioned within a
display stack, such as described herein. However, it will be
apparent to one skilled in the art that some of the specific
details presented herein may not be required in order to practice a
particular described embodiment, or an equivalent thereof.
[0105] Thus, it is understood that the foregoing descriptions of
specific embodiments are presented for the purposes of illustration
and description. These descriptions are not exhaustive nor intended
to limit the disclosure to the precise forms recited herein. To the
contrary, it will be apparent to one of ordinary skill in the art
that many modifications and variations are possible in view of the
above teachings. Particularly, it is understood that an optical
imaging array can be formed in a display stack in a number of
suitable ways.
[0106] Further, in certain examples, an optical imaging array can
be partially integrated into a display stack layer and,
additionally, partially disposed below a display stack. For
example, in one embodiment, an organic light-emitting diode can be
used for both emitting and capturing light (see, e.g., FIG. 2E). In
this embodiment, an optical imaging array can also be positioned
below the display stack (see, e.g., FIGS. 2A-2D) in order to
capture light traversing inter-pixel regions of the display
stack.
[0107] More generally, it is understood in view of FIGS. 2A-2G that
various features of each described embodiment can be combined in
arrangements not shown or described above. For example, in one
embodiment, multiple optical imaging arrays or optical imaging
sensors can be operated together to capture additional
information.
[0108] In other examples, an optical imaging array can be used by
an electronic device (see, e.g., FIG. 1A) for different purposes at
different times or in different modes. For example, in one mode an
optical imaging array can be operated to obtain an image, or a
series of images, corresponding to a fingerprint of a user touching
a specific portion of an electronic device display (see, e.g.,
FIGS. 1A-2A). In another mode, the same optical imaging array can
be operated to obtain ambient color temperature information used to
adjust one or more characteristics of the display. In yet another
mode, the same optical imaging array can be operated as a proximity
sensor (e.g., can be used to detect a user's finger as it
approaches the display to, as one example, increase a duty cycle of
an input sensor in anticipation of a touch or force input).
[0109] Generally and broadly, FIGS. 3-5D depict various
arrangements of pixels, subpixel groups, and trace layouts that can
promote increased optical transmittance through a display such as
described herein. The various techniques and constructions
described below can be combined with any of the embodiments
depicted and described in reference to FIGS. 2A-2G.
[0110] For example, FIG. 3 depicts a through-display imaging
architecture 300 for an organic light-emitting diode display that
facilitates imaging of a fingerprint of a user 302 through a
display stack 304. The display stack 304 can be configured in any
suitable manner, such as described above in reference to FIGS.
2A-2G; this description is not repeated.
[0111] As with other embodiments described herein, the
through-display imaging architecture 300 also includes an optical
imaging array 306 positioned below, and at least partially aligned
with, an imaging aperture 308. In some cases, the optical imaging
array 306 may have a larger area than the imaging aperture 308
(such as shown), but this may not be required.
[0112] In this embodiment, the display stack 304 defines multiple
regions having different pixel densities, defined by different
pixel/subpixel pitch. More specifically, as shown, a first pixel
density above the imaging aperture 308--identified as the pitch
g.sub.1--is lower than a second pixel density in other regions of
the display having a smaller pixel pitch. In other words, pixels of
the display stack 304 can be more sparsely distributed above the
imaging aperture 308. As noted with respect to other embodiments
described herein, sparsely distributed pixels (e.g., lower pixel or
subpixel density) are associated with a larger inter-pixel area
which, in turn, locally increases the optical transmittance of the
display stack 304 above the imaging aperture 308.
[0113] Pixels of the display stack 304--or other display stacks
having reduced pixel density and, additionally, increased optical
transmittance--can be distributed in any suitable manner or
pattern. Example configurations are depicted in FIGS. 4A-5C.
However, it may be appreciated that these embodiments are not
exhaustive and other configurations and constructions are
possible.
[0114] FIG. 4A depicts an example arrangement of pixels 400a (also
referred to as a pixel or subpixel distribution pattern) of a
display stack defining a region of reduced pixel density resulting
in locally-increased optical transmittance. In this embodiment,
generally square-shaped elements are distributed in a regular grid
pattern, each of which is understood to be a pixel or subpixel of a
display such as described herein; these elements are not
individually labeled for simplicity of illustration. In a central
region of the example arrangement of pixels 400a, a set of pixels
in the grid are skipped or otherwise removed, defining holes in the
grid pattern of pixels. These omitted pixels (e.g., omitted pixel
regions 402, 404, 406) locally increase the optical transmittance
of the display stack.
[0115] The pattern shown in FIG. 4A is merely one example. FIG. 4B
depicts another example arrangement of pixels 400b of a display
stack resulting in locally-increased optical transmittance showing
an array of square elements, each of which is understood to be a
pixel or subpixel of a display such as described herein. In this
example, sections of rows and/or columns can be omitted to define
omitted pixel regions 408, 410, 412. By omitting sections of rows
and/or columns, anisotropic pixel density can be achieved; an
average horizontal pixel density of the example arrangement of
pixels 400b may be greater than an average vertical pixel density
of the example arrangement of pixels 400b.
[0116] In yet another example, a two-dimensional area of omitted
pixels is possible. For example, FIG. 4C depicts another example
arrangement of pixels 400c of a display stack resulting in
locally-increased optical transmittance. In this example, an
interior region of pixels 414 defines a two-dimensional pattern of
omitted pixels.
[0117] The example embodiments described above in reference to
FIGS. 3-4C are provided, generally, for purposes of explanation and
should not be construed as limiting. To the contrary, one of skill
in the art will appreciate that many different means of defining
different pixel densities into a single display are possible in
view of the various embodiments described herein.
[0118] For example, in some embodiments, a low pixel density region
can be characterized by omitting every other pixel. In another
example, a low pixel density region can be characterized by
omitting pixels in a geometric pattern such as, but not limited to:
concentric shapes; serpentine patterns; spiral patterns; arbitrary
patterns; and so on. In some cases, a display stack can define a
pixel density transition region between a high pixel density region
and a low pixel density region. In other cases, a transition region
may not be required.
[0119] In still other embodiments subpixel groups in a region of a
display stack can be modified to provide locally-increased optical
transmittance. FIGS. 5A-5C depict various examples.
[0120] FIG. 5A depicts an example arrangement of subpixels 500a of
a display stack defining a region of reduced pixel density
resulting in locally-increased optical transmittance. In
particular, the example arrangement of subpixels 500a as depicted
includes sixteen groups of subpixels, one of which is identified as
the subpixel group 502. The subpixel group 502 includes three
subpixels, namely a red subpixel 504, a green subpixel 506, and a
blue subpixel 508. In this embodiment, one or more subpixel groups
can omit one or more colors from the group, resulting in incomplete
subpixel groups, one of which is identified as the incomplete
subpixel group 510. In this embodiment, the omitted subpixels
increase an inter-pixel area 512 that, in turn, locally increase
optical transmittance of the display stack. In this example a blue
pixel is omitted from the incomplete subpixel group 510 whereas a
horizontally-adjacent incomplete subpixel group may omit a red
pixel. In this manner, adjacent incomplete subpixel groups omitting
different subpixel colors can be operated together to produce a
wide range of colors.
[0121] In other cases, subpixel groups can be shifted to define an
area of decreased pixel density. FIG. 5B depicts an example
arrangement of subpixels 500b of a display stack defining a region
of reduced pixel density resulting in locally-increased optical
transmittance. In this example, a set of subpixel groups--including
the subpixel group 514--are moved away from a central region of an
inter-pixel area 516, thereby increasing optical transmittance
within the inter-pixel area 516.
[0122] In yet another embodiment, subpixel groups can share one or
more large-size subpixels. In particular, FIG. 5C depicts an
example arrangement of subpixels 500c of a display stack defining a
region of reduced pixel density resulting in locally-increased
optical transmittance. In the illustrated embodiment, subpixel
groups 518 and 520 share a large-size common pixel. As a result of
this construction, each subpixel group 518 and 520 independently
occupy a smaller area which, in turn, increases an area of an
inter-pixel region 522, thereby increasing optical transmittance
within the inter-pixel area 522.
[0123] Still some embodiments can locally increase optical
transmittance of a display stack in a different manner. For
example, in some embodiments, a thin-film transistor layer and/or a
column-row addressing/trace layer of a display stack can be formed
in a manner that locally increases inter-pixel regions and, in
turn, increases optical transmittance of a display stack. FIG. 5D
depicts an example arrangement of subpixel drive lines 500d of a
display stack defining a region of increased inter-pixel optical
transmittance. In particular, drive lines for each subpixel of an
arrangement of subpixel groups can be shifted in a particular
region of a display stack to increase the area of inter-pixel
regions. For example, drive lines for a first and second row of
subpixel groups--identified as the drive lines 540, including a
first drive line 540a and a second drive line 540b--can be arranged
in a non-grid pattern to define inter-pixel regions of increased
area (e.g., inter-pixel regions 544a-544e). In this manner, the
thin-film transistor layer and/or the column-row addressing/trace
layer defines discrete regions of high optical transmissivity and
regions of low optical transmissivity.
[0124] It may be appreciated that the foregoing description of
FIGS. 3-5D, and various alternatives thereof and variations thereto
are presented, generally, for purposes of explanation, and to
facilitate a thorough understanding of various possible
arrangements of pixels, subpixels, traces, and/or thin-film
transistor structures of a display stack that can promote
locally-increased optical transmittance through the display stack.
However, it will be apparent to one skilled in the art that some of
the specific details presented herein may not be required in order
to practice a particular described embodiment, or an equivalent
thereof.
[0125] Thus, it is understood that the foregoing descriptions of
specific embodiments are presented for the purposes of illustration
and description. These descriptions are not exhaustive nor intended
to limit the disclosure to the precise forms recited herein. To the
contrary, it will be apparent to one of ordinary skill in the art
that many modifications and variations are possible in view of the
above teachings. Particularly, it is understood any suitable pixel,
subpixel, trace, and/or thin-film transistor layout that promotes
locally or globally increased optical transmittance may be
possible. As noted above, these embodiments can be combined with
embodiments described in reference to FIGS. 2A-2E in any suitable
manner. For example, an imaging aperture such as shown in FIG. 2A
can be positioned below and/or aligned with a low pixel-density
region such as described in reference to FIG. 3-5C and,
additionally, can be positioned below and/or aligned with a
thin-film transistor layer such as described in reference to FIG.
5D.
[0126] Similarly, it may be appreciated that regions of different
pixel densities can be positioned anywhere within an electronic
device display. For example, FIG. 6A depicts an electronic device
600 incorporating a display stack defining an active display area
602 that in turn defines a high pixel density region 604 and a low
pixel density region 606. In one embodiment, the low pixel density
region 606 is positioned above and aligned with an imaging aperture
(see, e.g., FIG. 2A) that in turn is positioned above and aligned
with an optical imaging array. In this example, when a user of the
electronic device 600 touches the active display area 602 above the
low pixel density region 606, the optical imaging array can image
the user's fingerprint. The user's fingerprint can be imaged when
the user's finger is stationary or moving. For example, in one
embodiment, the user's fingerprint can be imaged when the user
slides from one side of the low pixel density region 606 to another
side of the low pixel density region 606. In another example, the
user's fingerprint can be imaged when the user places his or her
finger onto the low pixel density region.
[0127] In some cases, the active display area 602 can display an
image or animation that encourages the user to touch a particular
part of the low pixel density region 606 in order that the user's
fingerprint can be captured. For example, in some embodiments, the
active display area 602 can display a shape within the low pixel
density region 606. The shape may be animated in a manner that
draws the user's attention. For example, the shape can pulse,
rotate in three dimensions, flash one or more colors, vibrate, and
so on. In other cases, other shapes, patterns, or animations are
possible.
[0128] In some examples, the electronic device 600 can generate one
or more supplemental outputs in addition to, or in place of the
operation of displaying an image or an animation described above.
Supplemental outputs can include, but may not be limited to:
playing a sound from a speaker; generating a haptic output with a
vibrating element; generating a haptic tap or set of haptic pulses
with a linear actuator; vibrating the display or housing;
increasing or decreasing perceivable friction of the display (e.g.,
electrostatic attraction or ultrasonic vibration); and so on or any
combination thereof.
[0129] Furthermore, in the illustrated embodiment, the low pixel
density region 606 is entirely inset within the high pixel density
region 604, but this may not be required. In the illustrated
embodiment, the low pixel density region 606 has a capsule shape,
but this may not be required. Further, in the illustrated
embodiment, the electronic device 600 is depicted as a handheld
portable electronic device (e.g., cell phone, tablet computer,
portable media player, and so on), but this is not required of all
embodiments.
[0130] For example, FIG. 6B depicts another electronic device 608
incorporating a display stack with a locally-increased inter-pixel
optical transmittance. In this example, a laptop computing device
includes a primary display that defines an active display area 610
that defines a high pixel density region 612 and a low pixel
density region 614. As with other embodiments described herein,
when an imaging aperture and an optical imaging array can be
positioned below the low pixel density region 614 in order to
capture an image of a user's fingerprint when the user touches the
active display area 610 within the low pixel density region
614.
[0131] In other cases, a secondary display of an electronic device
can additionally or alternatively include a high pixel density
region and a low pixel density region. For example, FIGS. 6C-6D
depict another electronic device 616 incorporating a display stack
with a locally-increased inter-pixel optical transmittance. In this
example, a secondary display of the electronic device 616 defines
an active display area 618 that in turn defines a high pixel
density region 620 and a low pixel density region 622. In this
example, the low pixel density region 622 abuts the high pixel
density region 620, disposed to one edge of the high pixel density
region 620. In this embodiment, as with others described herein,
the low pixel density region 622 can be positioned above an imaging
aperture that in turn is positioned above an optical imaging array.
As a result of this construction, an image of a fingerprint of a
user can be captured when a user touches the low pixel density
region 622.
[0132] Generally and broadly, FIGS. 7 and 8 depict simplified flow
charts corresponding to various ordered and/or unordered operations
of methods described herein. It may be appreciated that these
simplified examples may be modified in a variety of ways. In some
examples, additional, alternative, or fewer operations than those
depicted and described may be possible.
[0133] FIG. 7 is a simplified flow chart depicting example
operations of a method of capturing an image of an object touching
a display, such as described herein. The method can be performed,
in whole or in part, by a processor or circuitry of an electronic
device such as described herein (see, e.g., FIGS. 1A, 2A-2E, and so
on).
[0134] The method 700 includes operation 702 in which a touch to a
display of an electronic device is detected. The initial touch can
be detected using any suitable sensor or combination of sensors
including but not limited to touch sensors and force sensors.
Example touch sensors include, but are not limited to: capacitive
touch sensors; optical touch sensors; resistive touch sensors;
acoustic touch sensors; and so on. Example force sensors include,
but are not limited to: capacitive force sensors; resistive force
sensors; piezoelectric force sensors; strain-based force sensors;
inductive force sensors; and so on.
[0135] Once a touch is detected at operation 702, the method 700
continues to operation 704, in which a touch centroid is optionally
determined. The centroid (e.g., geometric center) can be
calculated, determined, or estimated using any suitable technique.
In addition to determining the centroid of the touch, a total
contact area can be determined.
[0136] The method 700 also includes operation 706 in which the
determined centroid and/or contact area are illuminated by a
display of the electronic device. As noted with respect to other
embodiments described herein, the illumination of the contact
centroid and/or contact area can be performed in any suitable
manner including, but not limited to: a specific/selected color,
sequence, or set of colors; a specific/selected modulation of
light; a specific/selected animation pattern (e.g., linear sweep,
radial sweep, radial expansion, and so on); non-visible spectrums
of light (e.g., infrared, ultraviolet, and so on); and so on or any
combination thereof.
[0137] The method 700 also includes operation 708 in which a
fingerprint image is captured by an optical imaging array of the
electronic device. As noted with respect to other embodiments
described herein, the operation of capturing an image of a
fingerprint (or, more generally, an image of whatever object
touches the display at operation 702) can include one or more
filtering operations such as: spatial filtering (e.g., point-source
filtering, beam-forming, and so on); thresholding; deskewing;
rotating; and so on.
[0138] FIG. 8 is a simplified flow chart depicting example
operations of a method of capturing an image of an object touching
a display, such as described herein. As with the method of FIG. 7,
the method 800 can be performed, in whole or in part, by a
processor or circuitry of an electronic device such as described
herein (see, e.g., FIGS. 1A, 2A-2E, and so on).
[0139] The method 800 includes operation 802 in which an alignment
image is displayed by a display of an electronic device. The
alignment image can be any suitable animated or static image. Once
the alignment image is shown, the method 800 progresses to
operation 804 in which a touch of the alignment image is detected
(e.g., via touch and/or force sensor). Thereafter, at operation
806, at least one subpixel of the display is illuminated below the
region touched by a user. Thereafter, at operation 808, at least a
partial image of a fingerprint of the user touching the display can
be assembled. Optionally, at operation 810, depth information
obtained from one or more side-illumination operations (see, e.g.,
FIG. 2D) can be collected to determine whether a false positive
fingerprint match should be rejected. In particular, based on
absence of depth information, the electronic device can reject a
positive fingerprint match.
[0140] One may appreciate that although many embodiments are
disclosed above, that the operations and steps presented with
respect to methods and techniques described herein are meant as
exemplary and accordingly are not exhaustive. One may further
appreciate that alternate step order or, fewer or additional
operations may be required or desired for particular
embodiments.
[0141] Although the disclosure above is described in terms of
various exemplary embodiments and implementations, it should be
understood that the various features, aspects and functionality
described in one or more of the individual embodiments are not
limited in their applicability to the particular embodiment with
which they are described, but instead can be applied, alone or in
various combinations, to one or more of the some embodiments of the
invention, whether or not such embodiments are described and
whether or not such features are presented as being a part of a
described embodiment. Thus, the breadth and scope of the present
invention should not be limited by any of the above-described
exemplary embodiments but is instead defined by the claims herein
presented.
[0142] Further, the present disclosure recognizes that personal
information data, including biometric data, in the present
technology, can be used to the benefit of users. For example, the
use of biometric authentication data can be used for convenient
access to device features without the use of passwords. In other
examples, user biometric data is collected for providing users with
feedback about their health or fitness levels. Further, other uses
for personal information data, including biometric data, that
benefit the user are also contemplated by the present
disclosure.
[0143] The present disclosure further contemplates that the
entities responsible for the collection, analysis, disclosure,
transfer, storage, or other use of such personal information data
will comply with well-established privacy policies and/or privacy
practices. In particular, such entities should implement and
consistently use privacy policies and practices that are generally
recognized as meeting or exceeding industry or governmental
requirements for maintaining personal information data private and
secure, including the use of data encryption and security methods
that meets or exceeds industry or government standards. For
example, personal information from users should be collected for
legitimate and reasonable uses of the entity and not shared or sold
outside of those legitimate uses. Further, such collection should
occur only after receiving the informed consent of the users.
Additionally, such entities would take any needed steps for
safeguarding and securing access to such personal information data
and ensuring that others with access to the personal information
data adhere to their privacy policies and procedures. Further, such
entities can subject themselves to evaluation by third parties to
certify their adherence to widely accepted privacy policies and
practices.
[0144] Despite the foregoing, the present disclosure also
contemplates embodiments in which users selectively block the use
of, or access to, personal information data, including biometric
data. That is, the present disclosure contemplates that hardware
and/or software elements can be provided to prevent or block access
to such personal information data. For example, in the case of
biometric authentication methods, the present technology can be
configured to allow users to optionally bypass biometric
authentication steps by providing secure information such as
passwords, personal identification numbers, touch gestures, or
other authentication methods, alone or in combination, known to
those of skill in the art. In another example, users can select to
remove, disable, or restrict access to certain health-related
applications collecting users' personal health or fitness data.
* * * * *