Note: Descriptions are shown in the official language in which they were submitted.
DESCRIPTION OF THE INVENTION:
FIELD OF THE INVENTION:
The present invention relates to safety aids for mobile communication device
users who are "walking
while texting". More particularly, the invention relates to using the camera
on the mobile device with
a correctly placed convex mirror to produce a wide angle frontal view on the
screen to aid navigation.
BACKGROUND OF INVENTION
Since the advent of compact hand-held touch-screen mobile communication
devices, broad
availability of various wireless networks, and good graphic user interfaces,
immediate wireless short
message exchanges are commonly used for communication between users. When
these conversations
become engaging, users often are reading or typing messages (texting) while
walking, keeping the
devices in their half-extended arms and bending their heads downward to read
the contents of the
screen. Most users hold the screens tilted, with the top ends of the devices
about a few degrees to 60
degrees above the horizon. In these "walking while texting" positions, the
obstacles above-ground
and on the ground more than a step ahead are outside of their visual fields.
While collisions with
pedestrians and stationery objects cause minor injuries, walking into moving
traffic have serious
consequences, and has prompted some towns to install traffic lights on the
ground just in front of the
crossing, in an attempt to catch the attention of the "walking while texting-
person.
Most mobile phones in the developed world have digital cameras, with lenses
having an angular FOV
of about 55 degrees, designed to produce images similar to how the human eye
sees without
significant distortion. Recent versions of these digital cameras have
dedicated Graphic Processing
Unit (GPU), allowing the conversion of camera views to images on the screen
continuously and
instantaneously, with control of transparency of images and merging of
displays as standard built-in
features of the operation. The speed of the messaging program is not altered
by the continuous display
from the camera, as the Central Processing Unit (CPU) of the device used for
general program
execution is hardly involved in the control of image displays.
1 of 7
CA 3045119 2019-06-04
Recent development in the operating systems of mobile devices allow devices to
run two programs on
the same screen, enabling simultaneous display of a graphic image and any
selected program. A part
of the screen can be dedicated to an instantaneous image from the camera,
while the other part can be
used to execute the messaging software. For older operating systems or as an
alternate approach,
immediate images from the camera can be displayed together with messaging
software by simple
alterations of the display control codes of the messaging software.
The present designs of most "messaging" or "texting" programs display each
text message sent and
received inside a demarcated area on the screen with opaque background called
a "text bubble". All
messages from the ongoing session are kept in sequence for immediate recall,
and can be displayed in
their respective "text bubbles" against an opaque background of the program.
This opaque
background and "text bubbles" can be made transparent by simple software
modification when
desired.
The need for a method to aid mobile device users avoid accidents while they
are walking and looking
at the screens is recognized. United States Patent Application 20140085334,
titled "Transparent
Texting-, proposes using the existing rear-facing camera of a mobile device as
an aid to "walking
while texting" user, by presenting a view of the ground the camera is pointing
at, but not in the
direction the user is heading. Another disclosure, United States Patent
9571803, also recognizes the
need, and proposes an additional adjustable external camera to produce an
image of the frontal view
of the user on the screen.
In the related subject of re-direction of camera views using an adapter with
reflective elements on
mobile phones, there are prior art disclosures by Hurst in United States
Patent 9019420, Zhang in
United States Patent 7967513, Roman in United States Patent 9544539,
Rothschild in United States
Patent 9128243, and Singh in United States Patent Application 2011/0081946.
2 of 7
CA 3045119 2019-06-04
In United States Patent 9019420, Hurst claims a removable optical system
comprising either prisms
or light pipes, to re-direct the camera view, with no provision for change of
angles or the angular
FOV of the camera. Both disclosures by Zhang and Roman are that of rigidly
fixed periscopes to re-
direct camera views. In United States Patent 9128243, Rothschild employs plain
mirrors adjustable in
direction, to redirect camera views for stealth photographic purposes, with no
alteration in the angular
FOV of the camera. In United States Patent Application 2011/0081946, Singh
proposes a system of
two mirrors that redirects the camera view, and is capable of view angle
variation, with no change in
the angular FOV. All these patents employ designs with multiple reflective
elements, are non-
collapsible, not light-weight nor structurally simple, and none provides a
wide angular FOV.
In the aspect of redirecting the camera view using refractive optical
elements, there are disclosures of
attachments to mobile devices by Kessler in United States Patent 9654675, and
Knapton in Great
Britain Patent 2512145.
In United States Patent 9654675, Kessler's prism system employs both the
refractive property of
curved surfaces and the internal reflective property of prisms, to redirect
and extend the camera view
to a maximum angular FOV of about 60 degrees utilizing material of the highest
possible refractive
index (Fig. 4D). This is about half the normal human binocular visual FOV, and
a 15 percent increase
in the usual angular FOV of about 53 degrees in the average mobile device
camera. In GB Patent
9019420, Knapton claims an adapter for recording sporting activities using a
mobile phone by re-
directing the frontal views, comprising one prism with two curved refractive
surfaces and another
element with one curved refractive surface. This is incapable of any
adjustment of angles, and based
on the figure (Figure 4) in the disclosure, provides less than 90 degrees of
angular FOV. Both designs
employ prisms, which have the disadvantage of being non-collapsible and bulky,
and both have
limited angular FOV, hence not optimal for "walking while texting" navigation.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a side view of a mobile communication device with the screen 101
facing up, and the rear
surface 102 with camera lens 103 facing down. The basic embodiment of this
invention comprises:
3 of 7
CA 3045119 2019-06-04
base 111, fixed to the rear surface 102, and connected to friction hinge 112,
the latter holding the
mirror backing 113, on which the convex mirror 114 rests, at a particular
angle. Images in the
foreground of the mobile device are reflected by convex mirror 114 into camera
lens 103.
DETAILED DESCRIPTION OF THE INVENTION
(Note that in this description, for simplicity, "mobile communication devices"
is simplified as
"mobile devices"; "angular field of view" is simplified as "angular FOV"; and
"convex mirror or
reflective surface- simplified as "convex mirror".)
This invention aims to deliver a wide angular view of the foreground to the
screen of a mobile device
user by re-directing the view of the downward pointing camera using a light-
weight, collapsible,
single reflective element adapter, together with pertinent software. It
employs a convex mirror placed
next to the rear camera lens within its angular FOV, at a particular angle to
direct a wide angular FOV
of the frontal horizon into the camera, and delivers such onto the screen,
when the mobile device is
held in the "walking while texting" position described. To produce the desired
effect, there are criteria
for both the shape and size of the convex mirror, and for the placement of the
convex mirror in
respect to the lens of the camera, all being described in details herein. The
second component of the
invention comprises the appropriate software and modification of the resident
software of the
particular mobile device, to manipulate the images captured by the camera, and
to place these images
onto the screen, such that the path and obstacles ahead in the direction of
travel are within the user
area of visual attention. The third component of the invention comprises a
mechanical system, herein
called a "tilt assembly", which holds the convex mirror in the preferred and
required position, with
capability of safe stowage of the convex mirror. Depending on the design of
the mobile device, an
additional mechanical positioning system is at times needed to move the "tilt
assembly" to the
required position next to the camera lens, such as in the case when the lens
is positioned along the
edge of the rear surface of the mobile device.
In particular, the convex mirror redirects a frontal view of the horizon of
the "walking while texting"
device user into the camera lens while the camera is pointing downwards, with
the principal axis of
4 of 7
CA 3045119 2019-06-04
the camera lens being vertical, to 80 degrees from the vertical. This convex
mirror is placed at an
angle to the back of the device, and adjacent to the camera lens, of a
suitable size and curvature to
provide a wide angular FOV, with the principal axis of the convex mirror
pointing forward and in the
same plane as the axis of the camera lens.
Mirror with higher convexity, with a smaller radius of curvature, produces a
wider angular FOV.
Most mobile devices have camera lenses between 50 and 62 degrees in angular
FOV. This is much
less than the normal human binocular visual angle of 112 degrees, flanked by
another 40 degrees of
uniocular fields. Placing a convex mirror with one edge adjacent to the
inferior edge of the camera
lens, and at an angle of less then 80 degrees with the back of the device
(herein termed the 'tilt
angle'), produces a reflected image that is inverted with a wide-angle FOV of
over 100 degrees. The
width of the convex mirror has to cover the width of the camera horizontal
angular FOV to utilize the
full horizontal angular FOV of the camera. For most mobile device cameras,
when the radius of
curvature of the mirror is less than 5.5 cm, a horizontal angular FOV of over
120 degrees is achieved,
which is more than twice as wide as the angular FOV of the camera lens. When
this view is shown on
part of the screen, or as a background for the lines of messages, the "walking
while texting" user has a
good wide-angle view of what is in front, comparable to the normal human
visual field.
This method of providing a view of the frontal horizon using a convex mirror
positioned near the
standard rear camera of the mobile device is an improvement over using a
second camera attached
externally to the mobile devices, as described in United States Patent
9,571,803 in terms of simplicity,
size, weight and cost of implementation. In addition, this additional external
camera will need a wide-
angle lens of over 100 degrees to produce a comparable frontal view.
The angular FOV of over 120 degrees achieved employing a convex mirror with
this invention is an
improvement over Kessler's prism system as described in United States Patent
9,654,675, and
Knapton's system as described in UK Patent 2512145, both provide angular FOV
of less than 70
degrees. The disclosure by Rothschild in United States Patent 9,128,243,
redirects the frontal view to
of 7
CA 3045119 2019-06-04
the camera for photographic purposes, and does not increase the angular FOV of
the camera lens. The
present method is an improvement over United States Patent Application
20140085334, which
proposes using the existing rear-facing camera of a mobile device to provide a
view of the ground a
step ahead of the user, and not a redirected frontal view of the foreground.
In addition to the dimensions and the curvature of the convex mirror, there
are three other important
features with the placement of the mirror on the mobile device, namely, the
alignment, the proximity
of the convex mirror to the lens, and the angle the backing of the convex
mirror makes with the back
of the device (the "tilt angle"). The alignment required is for the principal
axis of both the convex
mirror and the camera lenses to be in the same plane, or close approximation
of such. The position of
the mirror is within several millimeters from the lower border of the camera
lens, to enable most of
the camera angular FOV to be covered by the smallest possible convex mirror,
for production of a
wider frontal view. It is also placed such that the camera lens itself is not
in the reflected image.
Lastly, the angle of the mirror backing, which is orthogonal to the principal
axis of the convex mirror,
is most effective at an acute angle to the back of the phone, such that the
view straight ahead of the
"walking while texting" user can be directed into the lens. This "tilt angle"
is dependent on the
manner the user holds the mobile device. The approximate relationship between
the angle the back
(and the screen) of the device makes with the horizon (angle A), and the angle
the backing of the
convex mirror makes with the back of the device (the tilt angle B) is given by
the equation: Angle B
= (45 degrees + 1/2( angle A)). When angle A is 90 degrees, the user is
holding the screen vertically,
which means the user is looking directly ahead, and there is no need for a
frontal view on the screen.
The second component of the invention is the software needed to display the
wide-angle image of the
frontal view of the user thus captured by the camera via the convex mirror on
to the screen, either in a
dedicated part of the screen, or as the background screen of the ongoing text
messages display.
Further software modification to remove the opacity of "text bubbles" and the
background of the
messaging programs increases the visibility of this frontal view. The acquired
image can also be
processed to detect certain warning signs captured, such as an area of
blinking red color created by a
flashing red warning light in the foreground, or a moving object. As mobile
devices have different
6 of 7
CA 3045119 2019-06-04
operating systems and resident software, this second component is specific for
each particular class of
devices and at times the particular models of the devices.
The third component of this invention comprises the mechanical structure to
secure the convex mirror
to achieve the three positioning requirements described above. The convex
mirror is held by a "tilt
assembly", which can vary from the simplest fixed bracket to hold the mirror
with an adjustable tilt
angle, to an assembly of tilt arms and levers on a base, with pivots and
fasteners for adjustment of the
angles between the arms, the levers, and the mirror. In the deployment
position, the combination of
the variable angles of the tilt arms with the camera backing, together with
the adjustable positions of
the mirror pivot pins along the tilt arms, provide different tilt angles for
the mirror, which can vary
from 45 degrees to about 80 degrees, to suit different users. The reverse
manipulation will bring the
convex mirror back into the stowage position where it can be locked in place.
The arrangement of a
base fixed in the middle of the back of the device works well for camera lens
positioned in the middle
portion of the device, and the base described can be glued down to the rear
surface of the mobile
device, or attached to the fitted protective cover of the device, or even be a
part of the mobile device.
Springs can be placed at appropriate parts of the tilt arm assembly to enable
one-touch release of the
stowed convex mirror, and the return of the mirror to the deployment position.
When the mobile device camera lens is situated off to the side of the rear of
the mobile device, a
positioning system is needed to move the "tilt assembly", with an extension on
which the
aforementioned base of the "tilt assembly" is affixed. The function of this
positioning system is to
bring the base of the "tilt assembly" to the required position below the
camera lens, and can consist of
a jointed radial arm that can be rotated and extended, or a track along which
an extensible arm can
slide along to bring the tilt arm assembly to the required position next to
the camera lens. The designs
of such positioning system aim at keeping the whole apparatus within the
boundaries of the plane of
the back of the device when stowed.
7 of 7
CA 3045119 2019-06-04
