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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a display device for displaying documents
containing text and other data for the sake of reading of the documents.
2. Description of the Background Art
A conventional portable computer device has been equipped with a display
facility comprising a single display screen. In this conventional display
facility, when a long text which cannot be contained entirely within this
single display screen is to be read, it has been necessary to use the
scroll function such that the displayed portion can be shifted
sequentially.
Now, when there is a figure in the document followed by a lengthy
explanation of this figure, there is a possibility that the figure itself
moves out of the display screen and therefore cannot be seen while a
reader reads through this lengthy explanation. Similarly, when the
explanation of the symbols to be used in the later parts of the document
Is given collectively in an earlier part of the document, until the reader
gets thoroughly familiar with the symbols, the reader must go back to the
earlier part very frequently while reading the later parts.
In these circumstances, if the document is presented in a form of a book,
the reader can mark the earlier part to be looked back easily by means of
a finger or a bookmarker, so that the reader can go back and forth between
the earlier part and the presently reading part very easily. However, in a
case of an electronic display device such as that provided on a
conventional portable computer device, it is quite cumbersome to switch
the displayed pages frequently, and in addition it is difficult to read
smoothly as the earlier part and the presently reading part cannot be seen
simultaneously.
This difficulty can be resolves by using the multi-window function, such
that two different parts of the document can be displayed simultaneously
in two different windows. Here, the multi-window function can be furnished
either by dividing the display screen or by allowing an overlap of one
window over another.
In a case of dividing the display screen, the displayed content of each
window remains entirely visible within each window so that the problem
concerning the impossibility of the simultaneous display of two different
parts can be resolved, but because the display screen itself has a limited
size especially in a portable computer device, the amount of data that can
be presented in each window at any one moment is rather limited, such that
the overview of the entire document is hard to comprehend and it actually
requires a longer time to read the document.
On the other hand, in a case of using a plurality of windows in overlap,
when the amount of data that can be presented in one window is increased,
the overlapped portion becomes large and the displayed content of the
overlapped window becomes invisible, so that the problem concerning the
impossibility of the simultaneous display of two different parts cannot be
resolved.
Moreover, in either case, the reader is required to carry out the
manipulations of the windows, which can be quite cumbersome.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a portable
display device capable of presenting a document in an easy to read format,
in which a simultaneous display of different parts of the document in
reasonable sizes can be made, by a simple operation of the device.
This object is achieved in the present invention by providing a display
device, comprising: document memory means for storing documents to be
displayed; at least two display screens for displaying the documents
stored in the document memory means; and display control means for
controlling displays of the documents on the display screens to be in a
linked mode in which the displays on the display screens are linked
together and in a separate mode in which the displays on the display
screens are independent from each other.
Other features and advantages of the present invention will become apparent
from the following description taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic perspective view of one embodiment of a portable
display device according to the present invention.
FIG. 2A is a perspective view of the display device of FIG. 1 in a state of
folding the display screens face to face.
FIG. 2B is a perspective view of the display device of FIG. 1 in a state of
folding the display screens back to back.
FIG. 3 is a schematic block diagram of the display device of FIG. 1.
FIG. 4 is an illustration of a basic function menu used in the display
device of FIG. 1.
FIG. 5 is an illustration of a page menu used in the display device of FIG.
1.
FIG. 6 is an illustration of page manipulation mode selection icons and
linked page switching mode selection sub-menu.
FIGS. 7A and 7B are sequential illustrations of both sides switching mode
and one side switching mode in the display device of FIG. 1.
FIGS. 8A, 8B, and 8C are illustrations of various displays in the linked
mode in the display device of FIG. 1.
FIG. 9 is a flow chart for a border treatment operation in a case of a wide
display function in the display device of FIG. 1.
FIGS. 10A and 10B are illustrations of two displays in the wide display
function requiring the border treatment operation in the display device of
FIG. 1
FIGS. 10C and 10D are illustrations of a display in the wide display
function before and after the border treatment operation in the display
device of FIG. 1
FIG. 11 is an illustration of various external devices connected with the
display device of FIG. 1.
FIG. 12 is a flow chart for a secret protection operation at a time of
transferring of the document in the display device of FIG. 1.
FIG. 13 is a flow chart for a secret protection operation at a time of
displaying of the document in the display device of FIG. 1.
FIGS. 14A and 14B are illustrations of the display device of FIG. 1
displaying a keyboard image and a ten keys image.
FIGS. 15A and 15B are illustrations of two displays in the separate mode in
the display device of FIG. 1.
FIG. 16 is a block diagram of a pen input mechanism that can be
incorporated in the display device of FIG. 1.
FIG. 17 is an illustration of entered pen inputs using the pen input
mechanism of FIG. 16 in the display device of FIG. 1.
FIG. 18 is a flow chart for a pen input operation in the display device of
FIG. 1.
FIGS. 19A and 19B are illustrations of an entered pen input and a stored
pen input data in the display device of FIG. 1.
FIG. 20 is an illustration of a display with pen input marks in the display
device of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, one embodiment of a portable display device
according to the present invention will be described in detail.
In this embodiment, the display device 100 generally comprises two left and
right display screen units 1 and 2 which define display screens A and B,
and which are attached together by a hinge 3 provided therebetween to be
freely spread out flat or folded up in half. On edges of these display
screen units 1 and 2, there are also provided a plurality of operation
buttons 4 to 7, at positions at which a thumb is going to be located when
the device 100 is held in a manner of holding a book. In a configuration
shown in FIG. 1, the operation buttons 4 and 7 are provided on a lower
left edge of the display screen unit 2 and a lower right edge of the
display screen unit 1, respectively, while the operation buttons 5 and 6
are provided on central bottom edges of the display screen units 2 and 1,
respectively. A number of these operation buttons may be increased or
decreased according to the need.
In addition, the device 100 is further equipped with an electronic pen 10
to be used for a handwriting input and a menu selection on the display
screen units 1 and 2, and an external device connector 11 for connecting
this display device 100 with external devices. The external device
connector 11 may be provided on a bottom edge of either one of the display
screen units 1 and 2 instead of a top edge of one of the display screen
units 1 and 2 as shown in FIG. 1, such that a connection code to be
connected at the external device connector 11 would not obstruct the
operations to be made by the user.
As shown in FIG. 2A, the display screen units 1 and 2 can be folded up
completely, face to face with each other, such that the display device 100
can be carried in hands easily while protecting the display screens A and
B of the display screen units 1 and 2 as well as the operation buttons 4
to 7.
Also, as shown in FIG. 2B, the display screen units 1 and 2 can be folded
up completely, back to back with each other, such that the display device
100 can be held in one hand while operating the display device 100. Here,
it is possible to provide a switch mechanism for detecting such a folding
of the display screen units 1 and 2 back to back, and erasing the display
on one of the display screen units 1 and 2 that is to be a back side (the
default setting is the display screen unit 1 which comes to the left side
in the spread). With such a switch mechanism, the secrecy of the displayed
content can be maintained with respect to the surrounding people to whom
the back side display screen is visible, and in addition, an unnecessary
battery power can be saved such that the display device 100 can remain in
an operable state for a longer period of time. It is also possible to make
each one of the display screen units 1 and 2 to be capable of being
activated/inactivated (i.e., turned on/off) separately such that the
unnecessary battery power can be saved by inactivating an unnecessary one
of the display screen units 1 and 2 whenever possible.
The display device 100 has an internal configuration as shown in FIG. 3,
which is similar to that of a usual micro-computer device except for the
presence of the two display screens A and B and various operation
switches. The commands entered from the input means such as the operation
buttons 4 to 7 and a pressure sensor 15 provided over the display screens
A and B are converted into appropriate electric signals at a signal
conversion unit 12 and the obtained electric signals are supplied into a
control unit 13. The control unit 13 includes an address controller 13a
for specifying an appropriate address of a document memory 14 storing the
documents to be displayed, and a memory controller 13b for accessing the
document memory 14 and reading out the appropriate document data stored at
the address specified from the address controller 13a to a display memory
14a through which the read out document data can be displayed on the
display screens A and B of the display screen units 1 and 2.
Here, the document memory 14 can be provided in a form of a built-in
semiconductor memory, as well as in an external memory device In various
media such as a floppy disk (FD) 20, an optical disk (CD) 21 such as a
compact disk, and an IC card (IC) 22, as shown in FIG. 1. The control unit
13 also has a function of interpreting the settings of the various
operation switches provided in this display device 100.
In this display device 100, the most basic function of reading is selected
by pressing an icon for the basic function provided on the display screen
B with a finger or the electronic pen 10, as shown in FIG. 4. When this
icon is pressed, the menu for selecting a reading with both of the display
screens A and B (spread), or a reading with only one of the display
screens A and B (left page, right page) is displayed. An entry "others" to
be selected in a case of using the additional functions other than the
basic function is also provided in this menu. When any one of the entries
related to the basic function of reading is selected by pressing it with a
finger or the electronic pen 10, a menu for selecting the document to be
displayed is displayed. This menu shows illustrations of usual locations
for the documents such as books and files. For example, the frequently
used books are located in the desk-top bookcase, the specialized books are
located in the library, the privately collected books are located in the
bookshelf. In addition, the currently working documents are located in the
work station, the recently used files are located in the desk cabinet, and
the less frequently used files are located in the file cabinet. When a
desired one of these locations of the documents is selected by pressing it
with a finger or the electronic pen 10, a menu for selecting the documents
contained at the selected location is displayed, from which a desired
document to be displayed can be selected by pressing an entry for that
desired document with a finger or the electronic pen 10.
When the desired document to be displayed is selected, the content of this
selected document is displayed, on both of the display screens A and B
when the "reading.cndot.spread" has been selected, or on either one of the
display screens A and B when the "reading.cndot.left page" or
"reading.cndot.right page" has been selected.
Here, the default setting for a page of the document to be displayed
initially is set to be either the last page read in the last reading of
this document in a case this document had been read previously but not
finished to the end, or the first page of the document in a case this
document has not been read previously or this document had been read to
the end before. This can be furnished by recording in each document file
the position (page) that is on the display screens A and B at a time of
closing of the display of each document file, and reading this information
at a time of opening of the display of each document file to set the
initial display page according to this information. Also, in a case the
power of the display device 100 itself had been turned off during the
previous reading of the document, the situation of the reading of this
document at a time the power had been turned off is resumed.
In a case of changing the displayed page, a page menu provided on the
display screen B is selected as shown in FIG. 5. When this page menu is
selected, a page scale indication is displayed as shown in FIG. 5, such
that when the user specifies a rough position of the desired page on this
page scale indication with a finger or the electronic pen 10, the address
controller 13a controls the the memory controller 13b to display the page
at a specified position by skipping the intermediate pages. This page menu
also has the "contents" entry for displaying the contents of the document.
When this "contents" entry is selected, the user can specify the index of
the desired section to be displayed in the displayed contents with a
finger or the electronic pen 10, in response to which the appropriate page
of the specified section is displayed.
Normally, the document is read page by page. However, in a case of ruffling
the pages, the operation buttons 4 to 7 are used. These operation buttons
4 to 7 can be provided in forms of mechanical switches or pressure
sensors. The displayed page can be changed by pressing these operation
buttons 4 to 7 with a finger such as a thumb or an index finger. Each of
these operation buttons 4 to 7 has a primary function of moving the pages
ahead provided by an elongated triangular button shown in FIG. 1, as well
as a secondary function of moving the pages back provided by a small
triangular button shown in FIG. 1. A brief pressing of any of these
operation buttons 4 to 7 moves the pages by one, while the continued
pressing of any of these operation buttons 4 to 7 moves the pages
continuously. In a case of using the pressure sensor for these operation
buttons 4 to 7, the speed of moving the pages can be changed according to
the strength at which these operation buttons 4 to 7 are pressed.
There are two major page manipulation modes provided in this display device
100, including a left and right linked mode and a separate mode. The
selection of the page manipulation mode is an important factor in the
operation of this display device 100, so that the dedicated icons for both
of these page manipulation modes are provided at an upper portion of the
display screen B as shown in FIG. 6, and the selection of the page
manipulation mode can be made by pressing an appropriate one of these
icons on the display screen B. The selected one of these icons is
indicated by a color or a positive-negative reversing, so that the user
can easily recognize the current setting of the page manipulation mode.
The linked mode is a mode in which the left and right pages are moved
together integrally, which is used for a usual reading the document. In
this linked mode, there are two ways of linked page switching including
the both sides switching and the one side switching, which can be selected
according to the preference of each user. The setting of this linked page
switching mode can be made by selecting the "others" entry in the basic
function menu and then selecting a sub-menu for this linked page switching
mode as shown in FIG. 6.
As shown in FIG. 7A, in a case of the both sides switching mode, after the
reading of the pages displayed on both of the display screens A and B are
finished, both of these displayed pages (P1 and P2) can be switched to the
next pages (P3 and P4) by the pressing of any one of the operation buttons
4 to 7. This both sides switching mode is suitable for the reading with
the entire display device 100 placed within the view field of the user.
On the other hand, as shown in FIG. 7B, in a case of the one side switching
mode, the earlier page among the pages displayed on both of the display
screens A and B is switched to a new page when any one of the operation
buttons 4 to 7 is pressed. Thus, in this one side switching mode, any one
of the operation buttons 4 to 7 can be pressed after the reading of the
earlier page is finished and while reading of the later page is still in
progress, such that the already read one of the displayed pages can be
switched to the next page while the other page is read and there is no
need to wait for the switching of the displayed pages after the reading of
the other page is finished.
Here, it is also possible set the operation buttons 4 to 7 such that, when
one of the operation buttons 4 and 5 on the left display screen unit 1 and
one of the operation buttons 6 and 7 on the right display screen unit 2
are pressed simultaneously, both of the displayed pages can be switched in
the manner of the both sides switching mode even when it is in the
separate mode.
The separate mode is a mode in which the left and right pages can be moved
independently from each other. This separate mode is apparently used when
two different documents are to be displayed on the left and right display
screens A and B in the basic function menu, but this separate mode can
also be used conveniently in a case of displaying the same document on the
left and right display screens A and B as follows.
For example, in a case of reading the document in the linked mode, when
there is a figure or an explanation of symbols and the topics related to
such a figure or an explanation of symbols are going to appear in the
following pages, the separate mode can be selected to switch only the page
without a figure or an explanation of symbols while keep displaying the
page with a figure or an explanation of symbols. This can be achieved by
pressing only one of the operation buttons provided on the display screen
unit of the page to be switched. After the topics related to such a figure
or an explanation of symbols are over, the linked mode can be resumed to
display the currently reading pages on both of the display screens A and
B. In this manner, the reading of the document can be assisted by the
viewing of the relevant figures.
As another example, in a case of reading the document in the linked mode,
when it is desired to refer back to the earlier part that has already been
read, the separate mode can be selected to switch only one of the pages to
display the earlier part while keep displaying the currently reading part
on the other one of the pages. After the referring back to the earlier
part is finished, the linked mode can be resumed to display the currently
reading pages on both of the display screens A and B.
In a case of moving the pages fast by pressing the operation buttons
strongly, only the header and the figure or table are displayed. In a case
of moving the pages even faster, the figure or table is abbreviated to its
outline. Also, in a case of ruffling the pages, the speed of the change of
the display can be made faster by displaying only a part of each page,
just as when the pages of the book are ruffled without opening the book
completely.
Also, the operation of the control unit 13 can be adjusted according to the
strength by which the operation buttons are pressed, such that the pages
can be moved in units of 5 pages for the strongest pressing and in units
of 1 page for the light pressing, for example.
In addition to the basic display function described above, this display
device 100 is also equipped with a wide display function in which the left
and right display screens A and B are treated as a single display. This
wide display function is used in a case the document itself is given in
the spread format as in the wide figures, or in a case the widened display
of the normal single page is desired such that the letters can be
enlarged. In the former case, the document data contain the code for
requiring the widened display, so that the wide display function can be
activated automatically in response to this code. Here, however, in a case
the display device 100 itself has been operated in the single display mode
with only one of the display screens A and B, only a half of the page in
the spread format will be displayed on that single display screen, unless
the operation to switch the display mode to the double display mode is
made.
Now, in this display device 100, unlike the usual book using papers, what's
on the left page and what's on the right page may not necessarily be
stable depending on the manner of page manipulation during the reading.
Namely, there is a case in which a figure given in the spread format as
shown in FIG. 8A appears in a middle of the straightforward page by page
reading at such a position that only the right display screen B becomes
available for this figure in the spread format while the left display
screen A must be used for displaying the immediately previous text as
shown in FIG. 8B. At this point, when one of the operation buttons 4 to 7
is pressed in the usual linked mode, both of tile left and right pages are
switched to next pages, so that only the left display screen A becomes
available for this figure in the spread format while the right display
screen B must be used for displaying the immediately following text as
shown in FIG. 8C, such that only a half of this figure in the spread
format can be displayed at any moment, and the entire figure will not be
displayed properly. In such a case, the address controller 13a recognizes
the code requiring the widened display contained in the document data and
operates in the fine adjustment mode to display the entire figure in the
spread format properly as shown in FIG. 8A.
In a case the widened display of the normal single page is desired, the
user is required to carry out the following operation. Namely, the user
must selects the "others" entry in the basic function menu and a sub-menu
for the wide display function. In this case, the display device 100 is
used in an orientation which is rotated from the normal orientation by
90.degree. either in the clockwise direction or in the counter-clockwise
direction. Here, if the operation buttons are also provided on the upper
edges of the left and right display screen units 1 and 2, the display
device 100 can be rotated in either one of the clockwise and
counter-clockwise directions freely. However, when the operation buttons 4
to 7 are provided as shown in FIG. 1, whether to rotate the display device
100 in the clockwise direction or in the counter-clockwise direction can
be determined according to one of the left and right hands that the user
wishes to use for the manipulation of the operation buttons. Namely, when
the user wishes to use the left hand for the manipulation of the operation
buttons, the display device 100 must be rotated in the clockwise
direction, whereas when the user wishes to use the right hand for the
manipulation of the operation buttons, the display device 100 must be
rotated in the counterclockwise direction,
In a case of the wide display function described above, there arises the
problem of the display at the border of the display screens A and B.
Namely, the display content located on the border of the display screens A
and B must be divided Into two, but when the small letters are located on
the border of the display screens A and B, the dividing of the small
letters into two makes it difficult to read. In this display device 100,
this problem is resolved as follows.
Namely, the display content is parallely shifted to displace the small
letters from the border of the display screens A and B. Here, the dividing
of the large letters or the figures would not severely damage the
readability of the document, so that this parallel shifting is made only
when the letters smaller than a prescribed size are located on the border
of the display screens A and B. Here, the small letters means the normal
sized letters without any ornamentation or enlargement.
This parallel shifting is achieved by the control unit 13 according to the
flow chart of FIG. 9 as follows.
First, at the step 1001, whether one line (either a row or a column) of
small letters is going to come on the border when the document is
displayed straightforwardly or not is checked. In other words, the
occurrence of situation as shown in FIG. 10A or 10B in which the entire
line of the small letters comes on the border is detected. If this is not
the case, the process proceeds to the step 1003. On the other hand, when
this is the case, next at the step 1002, the entire display content on the
side which contains larger part of that line of the small letters (display
screen A in FIGS. 10A and 10B) is shifted to put that line of the small
letters entirely within that side. In general, the document has some
margins at the edges, so that this shifting does not cause any
inconvenience.
At the step 1003, whether a small letter of an isolated letter series is
going to come on the border when the document is displayed
straightforwardly or not is checked. In other words, the occurrence of
situation as shown in FIG. 10C in which the small letter "C" of the
isolated letter series "ABCD" comes on the border is detected. If this is
not the case, the process proceeds to the step 1005. On the other hand,
when this is the case, next at the step 1004, the entire display content
on both sides are shifted toward the side which contains larger part of
that small letter (display screen B in FIG. 10C) to place the border
between the adjacent small letters, as shown in FIG. 10D. Alternatively,
because the isolated letter series usually have some margin spaces around
themselves, the isolated letter series alone may be shifted instead of the
entire display content.
Finally, after the shifting at the steps 1002 and 1004 are made, the actual
display is carried out.
Here, by storing the result of the shifting in the document memory 14
through the memory controller 13b, this shifting operation becomes
unnecessary in the later reading occasions. Alternatively, the document
data to be stored in the document memory 14 may be subjected to this
shifting operation in advance, either by using this display device 100 or
the other device capable of carrying out the same operation, such that
there is no need to carry out this shifting operation at a time of actual
display and therefore the proper display can be obtained more quickly.
Now, this display device 100 can be used in conjunction with various
external devices connected at the external device connector 11, as shown
in FIG. 11. For the connection, the cables and cords are used in FIG. 11,
although the radio transmission type connection using lights such as
infrared rays or electromagnetic waves may be used instead. Among the
external devices shown in FIG. 11, an external battery 30 is useful for
the extended outdoor use of this display device 100. Also, the external
memory 31 such as an optical disk device which records a large number of
documents and dynamic images can be connected for the purpose of viewing
these documents and dynamic images on this display device 100. Also, the
video tape recorder 32 can be connected for the purpose of viewing the
video image on this display device 100. Also, the external processor 33
can be provided to separate those functions of the display device 100
other than the basic display functions, such that the display device 100
itself can be made so light weighted as to be practically portable.
In addition, the keyboard 34 can be connected as the input device.
Moreover, when this display device 100 is used in conjunction with the
bookrest equipped with the keyboard, on which this display device 100 can
be mounted, this display device 100 can be used in the manner of a usual
desk-top computer.
Furthermore, the other computer such as a desk-top personal computer or a
work station 36 can be connected such that the document entered from the
computer 36 can be viewed on this display device 100. Here, for example,
even when the user is working in the office equipped with the desk-top
personal computer 36, in a case the user wishes to recline on the seat to
relax himself while reading the document, it is more convenient to use
this display device 100 held in hand rather than the display device
attached to the desk-top personal computer 36. In this case, the document
to be displayed is supplied from the desk-top personal computer 36 rather
than the document memory 14.
Another purpose for connecting the other computer is to transfer the
documents from that other computer to the display device 100, and to take
the display device 100 outside, such that the documents of the other
computer can be viewed even when the user is away from that other
computer. In this case, as the display device 100 is taken outside, there
arises a need to be cautious about the handling of the secret docu | | |
