Note: Descriptions are shown in the official language in which they were submitted.
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TIMEPIECE AND CHRONOMETER WITH OVERLAPPING,
SEPARATELY DRIVEN ANALOG AND DIGITAL DISPLAYS
Techincal Field
The present invention relates to the field of electronic timepieces, meaning
timepieces
having an electronic oscillator, such as a quartz crystal oscillator, that
serves as the time
standard for the timepiece. More specifically, the present invention relates
to display
S technologies for electronic timepieces, where the display arrangement
includes both analog
and digital time indicators.
Background Art
To receive reasonable consumer acceptance, a modern electronic wristwatch or
other
body-worn timepiece must have certain basic features and capabilities. First,
it must be fairly
accurate--errors of less than 10 seconds per month are common in the industry.
It must be
convenient to operate and have a highly visible time display--preferably a
display easily
visible in both bright sunlight and low light conditions. The cost of
acquiring and maintaining
the timepiece must be reasonable. Finally, it must have a combination of
features, displays,
and overall appearance that are sufficiently innovative or otherwise appealing
to make
consumers want to wear it.
Watches that incorporate both a conventional, mechanically-driven, analog-type
display and a digital, electrically-driven display have become popular as both
consumers and
manufacturers have realized that both types of displays have certain
advantages in electronic
body-worn timepiece applications. When electronic watches were new, consumers
typically
wanted to "advertise" that they possessed an electronic watch by having some
sort of visible
digital display. At the time, "solid state" watches were considered by many to
be more
reliable, more prestigious, and more desirable than their old-fashioned,
mechanically-driven
counterparts. Watch manufacturers thus sought to meet consumer demand by
developing
digital electro-optical displays that were suitable for electronic wristwatch
applications.
?5 However, the initial digital-display watches offered by manufacturers had
many
shortcomings. ~t'ristwatches with digital light-emitting diode (LED) displays
were bulky and
consumed so much power that the display was ordinarily off, requiring
inconvenient two-
handed operation by the wearer to command the display to "turn on." Moreover,
while LED
displays were highly visible at night, they were very hard to read in bright
sunlight. The
earliest liquid crystal displays (LCD} used in electronic watches consumed far
less power than
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LEDs. but these displays typically had an unacceptably short lifetime. The
first LCDs also
had contrast problems that limited users to fairly narrow viewing angles.
Advances in
electronics, display, and battery technology have resolved many of these
problems, making
current electro-optical displays much more practical for body-worn timepiece
applications.
However, although currently available digital displays are far more
serviceable for
watch applications than were their predecessors, consumers' preferences have
changed. As
electronic watches became readily and cheaply available in the market, their
"prestige" wore
off. Consumers also came to realize that while a digital display was
convenient in some
respects, it was inconvenient in many others.. Generally speaking, it is
easier to tell the time
by glancing at an analog clock face than by reading a relatively small set of
numbers.
Moreover, consumers are thought to prefer analog displays to quickly assess
time intervals,
i.e., how much time has elapsed since a specified time or how much time
remains before a
specified time. For example, if it is currently 2:25 and one has an
appointment at 3:00,
consumers may find it easier to determine from an analog display that the
appointment is 35
minutes away.
For these reasons, electronic wristwatches that contain complimentary analog
and
digital displays have become popular. A number of these types of wristwatches
actually do
not contain analog components, but rather, utilize an electronic display that
simulates an
analog display. The following U.S. Patents all disclose dual electronic
displays where the
analog-like portion of the display (i.e., a radial display similar to a clock
face that is intended
to convey the time of day in hours and minutes) does not include a
conventional, motor-driven
hour hand and minute hand: U.S. Patent No. 4,198,810, issued on April 22, 1980
to
Fahrenschon; U.S. Patent No. U.5. Patent No. 4,077,032, issued on February 28,
1978 to
Volkman; U.S. Patent No. 4,095,405, issued on June 20, 1978 to Tanaka; and
U.S. Patent No.
4,320,484, issued on March 16, 1982, to Burdet.
On the other hand, U.S. Patent No. 3,911,665, issued on October 14, 1975 to
van
Berkum, discloses a wristwatch having complimentary mechanically-driven analog
and
electrically-driven digital displays. However, van Berkum's alphanumeric
digital display is
limited to the on-command display of the date. At the user's command, passing
seconds can
be electronically displayed via a "seconds marker," described as a single LED
or a relatively
small group of LEDs that flash at the rate of 1 Hz. U.S. Patent No. 4,436,435,
issued on
March 13, 1984 to Ushikoshi, discloses a wristwatch having complimentary
analog and digital
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displays, where the digital display is located above (or in approximately the
same plane) as
the analog watch dial, thus allowing for a thin overall design. The wristwatch
disclosed by
Ushikoshi provides a conventional analog display that may or may not include a
second hand,
and a complimentary digital display that indicates hours and minutes in
alphanumeric format.
The digital display may or may not also include an alarm indicator and a
flashing colon
between the hours and minutes that indicates passing seconds. In Ushikoshi's
wristwatch,
both displays are driven by a single battery and a single time standard and
timing circuit.
The present invention comprises a dual-display electronic wristwatch that
incorporates
a novel arrangement of the analog and digital displays, and utilizes separate
batteries, time
standards, and driving circuits for each display. Rather than displaying the
same time-of day
information in two separate formats, or related time/date information, as
disclosed in the
above-described prior art, the present invention displays time-of day
information in analog
format and passing seconds in alphanumeric format. Thus, the present invention
is both a
timepiece and a chronometric instrument, enabling the user to readily
ascertain the both the
I S time-of day and the elapsed time between successive events with reasonable
precision.
Finally, the present invention provides a particularly unique and appealing
appearance.
Best Mode for Carrying Out the Invention and Summary
The present invention is a timepiece and chronometer that displays the time of
day in
an analog display format superimposed over passing seconds alphanumerically
displayed on
?0 an LCD digital display. The timepiece comprises a watch case with a display
opening that,
for the purposes of this disclosure, is designated as the display area, a
transparent watch
crystal, an electrically-driven digital LCD display that is substantially the
same size as the
display area, an electrical digital display driver, a conventional electrical
analog watch
movement, and an analog display comprising an hour hand, minute hand, and an
interior
25 bezel. The digital LCD display indicates passing seconds by incrementally
displaying either
digits 00 through 59 or digits 01 through 60 for one second each, either in
dark numerals over
a light background, or vice versa. The analog display, which may include
luminescent
surfaces on one or more of its components, is superimposed over the digital
display, and
arranged such that the digital LCD display is viewed through the opening of
the interior bezel.
30 The hands of the analog display are driven by an electrical analog watch
movement located
beneath the LCD display that comprises a battery, a timing standard such as a
quartz crystal
oscillator, timing circuitry, a conventional stem and crown assembly, and a
hand moving
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assembly that extends upward through the LCD display and couples to the analog
watch
hands. The digital display driver, also located behind the LCD display,
couples to the digital
LCD display and comprises a battery, a timing standard such as a quartz
crystal oscillator, and
timing and display driving circuitry. The analog movement and the digital
display driver may
share the same electrical ground, but otherwise are electrically isolated from
one another.
The timepiece may also include markings on the interior bezel that facilitate
reading
the time of day from the analog display, and/or one or more outer bezels
coupled to the watch
case outside the display area that are marked with analog time indications.
The watch case
may also include a curved rear surface to insure a comfortable fit at the
wrist.
Brief Description of the Drawings
To further aid in understanding the invention, the attached drawings help
illustrate
specific features of the invention and the following is a brief description of
the attached
drawings:
FIG.I is a plan view of one embodiment of the present invention in a
wristwatch
application, showing the analog display superimposed over the digital display,
as it would
appear to a wearer.
FIG.2 is a cross-sectional view of one embodiment of the present invention in
a
wristwatch application, showing the arrangement of the displays, analog
movement, and
digital display driver within the watch case.
FIGs. 3A and 3B show the front and rear sides of the digital display driver of
the
present invention according to one embodiment.
FIG. 4 shows the digital LCD display according to an embodiment of the present
invention.
FIG. S shows the arrangement of digits of the digital LCD display, according
to one
embodiment of the present invention.
FIG. 6 is rear view of one embodiment of the present invention, showing the
arrangement of the analog movement and analog movement battery, and the
digital display
driver and digital display driver battery.
Disclosure of the Invention
The present invention comprises a dual-display electronic timepiece that
incorporates
a novel arrangement of the analog and digital displays, and utilizes separate
batteries, time
standards, and driving circuits for each display. Rather than displaying the
same time-of day
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information in two separate formats, or related time/date information, as
disclosed in the
above-described prior art, the present invention displays time-of day
information in analog
format and passim seconds in alphanumeric format. Finally, the present
invention provides
a particularly unique and appealing appearance. This disclosure describes
numerous specific
details that include specific structures and circuits in order to provide a
thorough
understanding of the present invention. One skilled in the art will appreciate
that one may
practice the present invention without these specific details. In addition,
while this disclosure
focuses on the application of the present invention to wristwatches, one
skilled in the art will
recognize that the present invention can be also be applied in the context of
any horological
instrument.
FIG. 1 shows the present invention 100 in a wristwatch embodiment, as it would
appear to a wearer. As shown in FIG. 1, timepiece 100 includes a watch case 1
OI . Looking
through the transparent crystal 104 (not shown in FIG. 1 ) and the display
opening 102 in
watch case 101, the wearer sees the digital display 105 and its alphanumeric
digits 106.
Superimposed over the digital display 105, the wearer sees an hour hand 108, a
minute hand
109, and an interior bezel 110 that comprise the analog display. Interior
bezel I10 is
symmetrically aligned with display opening 102, and further comprises an inner
edge 110b
that defines the inner opening of the interior bezel 110 and markings 1 l Oc
that facilitate the
reading of the time of day indicated by the position of the hour hand 108 and
the minute hand
109. Alphanumeric digits 106 displayed on digital LCD display 105 are sized
such that they
can be viewed through the inner opening of interior bezel 110, without being
blocked by
interior bezel 110.
In the embodiment shown in FIG. 1, interior bezel markings 110c comprise long
segments radially dispersed at approximate 15 degree intervals, and short
segments radially
dispersed between the long segments at approximate 3 degree intervals. While
FIG. 1 shows
short and long segments that indicate conventional hour and minute positions
on a clock, one
skilled in the art will recognize that interior bezel markings 1 l Oc could
comprise a variety of
other indications such as Roman, Arabic, or other alphanumeric characters,
alone or combined
with segments, dots or other markings or indications intended to facilitate
the determination
of the time of day indicated by the positions of hour hand 108 and minute hand
109. In a
preferred embodiment of the present invention, a luminescent material or
coating may be
applied to the viewing surface of hour hand 108, minute hand 109, and either
interior bezel
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markings I I Oc, or the surface of interior bezel 110, thus enabling the
wearer to easily read the
analog display in low ambient lighting conditions. Hour hand 108 and minute
hand 109 are
set as W a conventional timepiece using stem and crown assembly 119.
FIG. 2 is a cross-sectional view of a wristwatch embodiment of the present
invention,
showing the arrangement of the various components within the interior 103 of
the watch case
101 and case back I 18. As shown in FIG. 2, watch crystal 104 covers display
opening 102 in
watch case 101. Watch crystal 104 is retained by outer bezel 114, which may or
may not be
marked with indications intended to facilitate reading the time-of day from
the position of
watch hands I 08 and l 09. Immediately beneath watch crystal 104, FIG. 2 shows
a cross-
sectional view of minute hand 109, hour hand 108, and interior bezel 110.
Analog hands 108
and 109 are coupled to and rotate about hand moving assembly 112, which
extends upward
from analog watch movement 111 through center aperture 107 in LCD digital
display 105.
Center aperture 107 is symmetrically aligned with interior bezel 110 and
display opening 102.
Analog hands 108 and 109 can be manually positioned using stem and crown
assembly I 19
I S (not shown in FIG. 2).
Analog watch movement 111 is a quartz crystal or other self contained, battery-
powered electronic analog watch movement well known in the art, such as a
Citizen 2026 or
other readily available watch movements, and is thus not described in detail
here. Analog
watch movement II1 includes a conventional stem and crown assembly 119 and a
conventional analog hand moving assembly 112 that ordinarily would extend
through a
conventional watch face to couple to an hour hand 108 and a minute hand 109.
FIG. 2 shows LCD display driver 113 in cross-section, adjacent to analog watch
movement 111. LCD display driver 113 is electrically coupled to LCD display
105 via zebra
connector 117.
FIG. 2 also shows the relative positions of the edges of display opening 102,
interior
bezel 110, and LCD display 105 in a preferred wristwatch embodiment. Interior
bezel 110
is sized such that the outer edge l OSc of LCD display 105 is hidden from view
through the
watch crystal 104. In other words, outer edge 1 I Oa of interior bezel extends
beyond the outer
edge l OSc of LCD display 1 O5. Inner edge 11 Ob of interior bezel 110 is
smaller than outer
edge lOSc of LCD display 105. Display opening 102 in watch case 101 is sized
such that
outer edge 1 10a of interior bezel 110 is hidden from the wearer's view. One
skilled in the art
will recognize that although the wristwatch embodiment of the present
invention described
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in this disclosure depicts a circular design for watch case 101, display
opening 102, interior
bezel 110, and LCD display 1 O5, the present invention may be practiced in
timepieces with
other physical shapes (such as square, rectangular, oval, etc.) without
departing from the
present invention. Moreover, although not shown in FIG. 2, watch case 101 may
also include
a curved rear surface to insure a comfortable fit at the wrist.
FIGS. 3A and 3B show the front and rear sides of digital display driver 113.
Digital
display driver 113 includes the timing standard and electronic circuitry
necessary to drive the
LCD display 105 at a rate of 1 Hz. In the embodiment described in this
disclosure, digital
display driver 113 comprises a double-sided printed circuit board with the
following surface-
mounted CMOS electronic components: display driver integrated circuit 120,
electronic
timing standard 121, and chip capacitors 122-125, all shown in FIG. 3B. Timing
circuitry
using an electronic timing standard such as a quartz crystal oscillator and
electronic LCD
display driving circuitry for horological applications are both well known in
the prior art and
thus no further detail regarding the specifics of display driver 113 is
necessary or provided
in this disclosure.
FIG. 4 shows a close-up view of digital LCD display 105. Features of digital
LCD
display 105 shown in FIG. 4 include outer edge lOSc, two alphanumeric displays
106, each
of which are comprised of 7 uniquely-configured and separately-illuminated
segments 115,
display background 116 and center aperture 107. Digital LCD display 1 OS may
be configured
with an ordinarily-dark background 116 and ordinarily-dark segments 11 S. When
segments
115 are energized by display driver 113 they become light, thus producing
light alphanumeric
characters 106 on a dark background 116. Alternatively, digital LCD display
105 may be
configured with an ordinarily-light background 116 and ordinarily-light
segments 115. In this
embodiment, when segments 115 are energized by display driver 113, they become
dark, thus
producing dark alphanumeric characters 106 contrasted with a light background
116. FIG.
S shows the appearance of dark alphanumeric characters 106 on a light
background 116 in an
embodiment of the present invention wherein digital LCD display 1 OS displays
alphanumeric
characters 00 through 59. One skilled in the art will appreciate that
alternative embodiments
of the present invention may display alternate characters, such as O1 through
60, 0 through 59
(wherein digits 0-9 are not displayed with a leading 0), or 1 through 60
(wherein digits 1-9
are not displayed with a leading 0). Similarly, embodiments that display only
a subset of
characters 00-59 or O1-60, at a rate slower than 1 Hz will not depart from the
present
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invention. In other words, an embodiment comprising a digital LCD display that
displays
alphanumeric characters 00, 10, 20, 30, 40, and 50 for approximately 10
seconds each, but in
all other respects identical to this disclosure, would not depart from the
present invention.
The latter embodiment is not a preferred embodiment, however, because such an
embodiment
would render the chronometric function of the present invention less useful.
FIG. 6 is a plan view of a wristwatch embodiment of the present invention from
the
rear, with the case back 118 removed. FIG. 6 shows the relative positions of
analog
movement 111 with analog movement battery 126, and digital display driver 113
with digital
display driver battery 127. Other than possibly sharing the same electrical
ground through
IO watch case 101, analog movement 11 I with analog movement battery 126 is
electrically
isolated from digital display driver 113 and digital display driver battery
127. Consequently,
in this embodiment of the present invention, display driver 113 or display
driver battery 127
may fail without causing analog movement 111 or analog movement battery 126 to
fail and
without impacting the ability of the user of the present invention to
determine the time of day
15 from the analog display.
In sum, the present invention is a timepiece and chronometer that displays the
time of
day in an analog display format superimposed over passing seconds displayed
alphanumerically on an LCD digital display. The timepiece comprises a watch
case with a
case back and a display opening that, for the purposes of this disclosure, is
designated as the
20 display area, a transparent watch crystal, an electrically-driven digital
LCD display that is
substantially the same size as the display area, an analog display comprising
an hour hand,
minute hand, and interior bezel, an electrical analog watch movement, and a
digital display
driver. The digital LCD display indicates passing seconds by incrementally
displaying either
digits 00 through 59 or digits O1 through 60 for one second each, either in
dark numerals over
25 a light background, or vice versa: The analog display, which may include
luminescent
surfaces on one or more of its components, is superimposed over the digital
display, awanged
such that the digital LCD display is viewed through the inner opening of the
interior bezel.
The hands of the analog display are driven by an electrical analog watch
movement located
beneath the LCD display that comprises a battery, a timing standard such as a
quartz crystal
30 oscillator, timing circuitry, a stem and crown assembly, and a hand moving
assembly that
extends upward through the center aperture of the LCD display and couples to
the analog
watch hands. The digital display driver, also located behind the LCD display,
couples to the
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digital LCD display and comprises a second battery, a timing standard such as
a quartz crystal
oscillator, and timing and display driving electronic components and
circuitry. The analog
movement and the digital display driver may share the same electrical ground,
but otherwise
are electrically isolated from one another.
The timepiece may also include markings on the interior bezel that facilitate
reading
the time of day from the analog display, and/or one or more outer bezels
coupled to the watch
case outside the display area that may be marked with analog time indications.
Other embodiments of the invention will be apparent to those skilled in the
art after
considering this specification or practicing the disclosed invention. The
specification and
examples above are exemplary only, with the true scope of the invention being
indicated by
the following claims.
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