EP0845769A1
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Plasma display device driven in a subframe mode
Assignee: Hitachi Plasma Patent Licensing Co Ltd
•
Filing: 1997-10-06
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Granted: —
•
Expires: 2017-10-06
Abstract
Abstract The plasma display device has a plasma display panel (20) and a driving part for driving the plasma display panel (20) in a subframe mode. The driving part has a circuit (10) for calculating the length of one frame based on one period of a vertical synchronizing signal introduced along with an image signal from an external device, a circuit (11) for calculating the total number of sustaining pulses contained in one frame based on brightness information contained in the image signal, and a circuit (12) for calculating the length of one driving period required for displaying one frame. The length of one frame and the length of one driving period thus obtained are then compared in a comparing circuit (14). If the one frame length is found to be shorter than the one driving length, the total number of sustaining pulses or the number of scan lines will be reduced so that the one frame length becomes shorter than the length of one driving period, thus avoiding an extraordinary display.
Inventors
- 👤 Ayahito Kojima
- 👤 Masaya Tajima
- 👤 Hirohito Kuriyama
- 👤 Katsuhiro Ishida
- 👤 Akira Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:11
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/2007; G09G3/2018; G09G3/2022; G09G3/2029; G09G3/22; G09G3/28; G09G3/288; G09G3/291; G09G3/293; G09G3/294; G09G2310/00; G09G2310/06; G09G2310/066; G09G2320/00; G09G2320/06; G09G2320/0626; G09G2330/00; G09G2330/02; G09G2330/021; G09G2340/00; G09G2340/04; G09G2340/0407; G09G2340/0414; G09G3/292; G09G3/2927
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
210 words
A plasma display device comprising: a plasma display panel (20); and a driving part for driving the plasma
display panel (20) in a subframe mode in which one frame
for display is divided into a plurality of subframes and
a predetermined number of sustaining pulses is applied to
the plasma display panel (20) during each of the
subframes so as to cause a sustaining discharge; said driving part further comprising:- a first circuit (10) for calculating
a length of one frame for display according to one period
of a vertical synchronizing signal which is input from an
external device along with an image signal, a second circuit (11) for detecting a
total number of sustaining pulses contained in one frame
based on brightness information contained in said image
signal, a third circuit (12) for calculating
a length of one driving period of the plasma display
panel (20) necessary for displaying one frame based on
the total number of sustaining pulses detected by said
second circuit (11), a fourth circuit (14) for comparing
respective results from said first circuit (10) and said
third circuit (12), and a fifth circuit (16) for changing a
total number of sustaining pulses in one frame according
to a compared result in said fourth circuit (14).
Claim 2
Dependent Claim
60 words
The plasma display device according to claim 1,
wherein said fifth circuit (16) changes the total number
of sustaining pulses in a manner to reduce the same when
said fourth circuit (14) finds that the length of one
frame obtained by the first circuit (10) is shorter than
the length of one driving period obtained by the third
circuit (12).
Claim 3
Dependent Claim
60 words
The plasma display device according to claim 1,
wherein said fifth circuit (16) changes the total number
of sustaining pulses in a manner to increase the same
when said fourth circuit (14) finds that the length of
one frame obtained by the first circuit (10) is longer
than the length of one driving period obtained by the
third circuit (12).
Claim 4
Dependent Claim
72 words
The plasma display device according to claim 1,
wherein said driving part further comprises a sixth
circuit (18) for detecting a lapse of a predetermined
time period in which no change is detected once said
fourth circuit (14) has detected a change in a comparing
result, and wherein said fifth circuit (16) changes the
total number of sustaining pulses after said sixth
circuit (18) detects the lapse of the predetermined time
period.
Claim 5
Dependent Claim
55 words
The plasma display device according to claim 1,
wherein said first circuit (10), said third circuit (12)
and said fourth circuit (14) are comprised of a
microprocessor unit (29a) and a recording medium (29c) in
which a program for making said microprocessor unit (29a)
to function as said first, third and fourth circuit is
stored.
Claim 6
Dependent Claim
242 words
A plasma display device comprising: a plasma display panel (20); and a driving part for driving the plasma
display panel (20) in a subframe mode in which one frame
for display is divided into a plurality of subframes and
a predetermined number of sustaining pulses is applied to
the plasma display panel (20) during each of the
subframes so as to cause a sustaining discharge; said driving part further comprising:- a ROM table (29d) having a plurality
of addresses in which a combination of numbers of
sustaining pulses for respective subframes is stored, a first circuit (10) for calculating
a length of one frame for display according to one period
of a vertical synchronizing signal which is introduced
from an external device along with an image signal, a second circuit (11) for detecting a
total number of sustaining pulses contained in one frame
based on an address of said ROM table (29d), said address
which corresponds to brightness information contained in
said image signal; a third circuit (12) for calculating
a length of one driving period of the plasma display
panel (20) necessary for displaying one frame based on
the total number of sustaining pulses detected by said
second circuit (11), a fourth circuit (14) for comparing
results from said first circuit (10) and said third
circuit (12); and a fifth circuit (16) for changing an
address of the ROM table (29d) according to a compared
result in said fourth circuit (14).
Claim 7
Dependent Claim
69 words
The plasma display device according to claim 6,
wherein said fifth circuit (16) changes an address of the
ROM table (29d) in a manner to reduce a total number of
sustaining pulses contained in the address when said
fourtn circuit (14) finds that the length of one frame
obtained by the first circuit (10) is shorter than the
length of one driving period obtained by the third
circuit (12).
Claim 8
Dependent Claim
69 words
The plasma display device according to claim 6,
wherein said fifth circuit (16) changes an address of the
ROM table (29d) in a manner to increase a total number of
sustaining pulses contained in the address when said
fourth circuit (14) finds that the length of one frame
obtained by the first circuit (10) is longer than the
length of one driving period obtained by the third
circuit (12).
Claim 9
Dependent Claim
72 words
The plasma display device according to claim 6,
wherein said driving part further comprises a sixth
circuit (18) for detecting a lapse of a predetermined
time period during which no change is detected once said
fourth circuit (14) has detected a change in a compared
result, and wherein said fifth circuit (16) changes the
total number of sustaining pulses after said sixth
circuit (18) detects the lapse of the predetermined time
period.
Claim 10
Dependent Claim
54 words
The plasma display device according to claim 1,
wherein said first circuit (10), said third circuit (12)
and said fourth circuit (14) are comprised of a
microprocessor unit (29a) and a recording medium (29c) in
which a program for making said microprocessor unit (29a)
function as said first, third and fourth circuit is
stored.
Claim 11
Dependent Claim
224 words
A plasma display device comprising: a plasma display panel (20) having a
plurality of light emitting cells arranged in the form of
a matrix; and a driving part for driving the plasma
display panel (20) in a subframe mode in which one frame
for display is divided into a plurality of subframes and
a predetermined number of sustaining pulses is applied to
said plurality of light emitting cells in each subframe
while scanning the plurality of light emitting cells
line-sequentially; said driving part further comprising:- a first circuit (10) for calculating
a length of one frame for the display according to one
period of a vertical synchronizing signal which is
introduced from an external device with an image signal, a second circuit (11) for detecting a
total number of sustaining pulses contained in one frame
based on brightness information contained in said image
signal, a third circuit (12) for calculating
a length of one driving period of the plasma display
panel (20) necessary for displaying one frame based on
the total number of sustaining pulses detected by said
second circuit (11), a fourth circuit (14) for comparing
results from said first circuit (10) and said third
circuit (12); and a fifth circuit (16) for changing a
total number of scan lines, which are scanned in line-sequence,
according to a result from said comparing
circuit.
Claim 12
Dependent Claim
60 words
The plasma display device according to
claim 11, wherein said fifth circuit (16) changes the
total number of scan lines in a manner to reduce the same
when said fourth circuit (14) finds that the length of
one frame obtained by the first circuit (10) is shorter
than the length of one driving period obtained by the
third circuit (12).
Claim 13
Dependent Claim
60 words
The plasma display device according to
claim 11, wherein said fifth circuit (16) changes the
total number of scan lines in a manner to increase the
same when said fourth circuit (14) finds that the length
of one frame obtained by the first circuit (10) is longer
than the length of one driving period obtained by the
third circuit (12).
Claim 14
Dependent Claim
72 words
The plasma display device according to
claim 11, wherein said driving part further comprises a sixth circuit (18) for detecting a lapse of a
predetermined time period during which no change is
detected once said fourth circuit (14) has detected a
change in a compared result, and wherein said fifth
circuit (16) changes the total number of scan lines after
said sixth circuit (18) detects the lapse of the
predetermined time period.
Claim 15
Dependent Claim
55 words
The plasma display device according to
claim 11, wherein said first circuit (10), said third
circuit (12) and said fourth circuit (14) are comprised
of a microprocessor unit (29a) and a recording
medium (29c) in which a program for making said
microprocessor unit (29a) to function as said first,
third and fourth circuit is stored.
Claim 16
Dependent Claim
218 words
A plasma display device comprising: a plasma display panel (20); and a driving part for driving the plasma
display panel (20) in a subframe mode in which one frame
for display is divided into a plurality of subframes and
a predetermined number of sustaining pulses is applied to
the plasma display panel (20) during each of the
subframes so as to cause a sustaining discharge; said driving part further comprising:- a first circuit (10) for calculating
a length of one frame for display according to one period
of a vertical synchronizing signal which is introduced
from an external device along with an image signal, a second circuit (291) for
calculating a maximum number of sustain pulses to be
displayed based on the length of one frame calculated by
the first circuit (10) and for calculating a maximum
brightness according to the maximum number of sustaining
pulses thus obtained; a third circuit (292) for detecting
an agreement of the maximum brightness calculated by said
second circuit (291) with a referential brightness
determined in advance; and a fourth circuit (293) for
calculating a number of sustaining pulses which
corresponds to said referential brightness when no
agreement is detected by said third circuit (292), and
for setting the calculated number of sustaining pluses to
be the maximum number of sustaining pluses.
Claim 17
Independent Claim
196 words
A method for driving a plasma display device
having a plasma display panel (20) and a driving part for
driving the plasma display panel (20) in a subframe mode
in which one frame for display is divided into a
plurality of subframes and a predetermined number of
sustaining pulses is applied to the plasma display
panel (20) during each of the subframes so as to cause a
sustaining discharge, the driving method comprising the
steps of: calculating a length of one frame for
display according to one period of a vertical
synchronizing signal which is input from an external
device along with an image signal; detecting a total number of sustaining
pulses contained in one frame based on brightness
information contained in said image signal; calculating a length of one driving period
of the plasma display panel (20) necessary for displaying
one frame based on the total number of sustaining pulses
detected at the detecting step; comparing the length of one frame with the
length of one driving period obtained in the respective
calculating steps; and changing a total number of sustaining
pulses in one frame according to a compared result
obtained in the comparing step.
References Cited (Backward Citations)
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