EP0458349A2
Expired / Lapsed
EP
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Liquid crystal display device
Assignee: Casio Computer Co Ltd
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Filing: 1991-05-24
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Granted: —
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Expires: 2011-05-24
Abstract
Abstract In a liquid crystal display device, to improve the contrast, the frame frequency is raised by scanning the scanning electrodes (X) of the liquid crystal display panel (17) a plurality of times during one field interval of the video signal. The scanning electrodes (X) are divided into two groups, which are scanned alternately. An image memory (M) is provided to store video signals. In scanning the liquid crystal display panel (17), the video signal from the video signal supplying source (11) and the video signal read from the image memory (M) are alternately supplied to the liquid crystal display panel. The image memory (M) stores only part of the video signal such as the video signal for every other horizontal interval or the signal consisting of the most significant bit only, not the entire video signal.
Inventors
- 👤 Tomohiro c/o Patent Dep. Dev. Div. Hamura Mogi
- 👤 Minoru c/o Patent Dep. Dev. Div. Hamura Usui
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 00:45
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3674; G09G3/3685; G09G2310/00; G09G2310/02; G09G2310/0202; G09G2310/0205
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
201 words
A liquid crystal display device, wherein the scanning electrodes of the liquid crystal display panel having a plurality of scanning electrodes and a plurality of signal electrodes are scanned by scanning means on the basis of the timing signal generated by timing signal generating means, while said signal electrodes are supplied with the video signal from a video signal source by means of signal electrode driving means, characterized by further comprising: memory means (M, M2, M3, M4, M5) for storing the video signal supplied from said video signal source; and selecting means (14, 214, 314, 414, 514) for alternately selecting the video signal read from said memory means and the video signal supplied from said video signal source and then outputting the selected signal; wherein said scanning means (18, 19, 20, 21, 22, 23, 222, 223, 322, 323, 422, 423, 522, 523) selects groups of said scanning electrodes in turns, while scanning said scanning electrodes a plurality of times during one field interval; and said signal electrode driving means (15, 16) receives the video signal from said selecting means and then drives said signal electrodes by using the video signal corresponding to the scanning electrodes being scanned by said scanning means.
Claim 2
Dependent Claim
21 words
A liquid crystal display device according to claim 1, characterized in that said video signal source contains television circuit means (11).
Claim 3
Dependent Claim
35 words
A liquid crystal display device according to claim 1, characterized in that said video signal source contains an A/D converter means (13, 213, 313, 413, 513) for converting an analog signal to a digital signal.
Claim 4
Dependent Claim
24 words
A liquid crystal display device according to claim 1, characterized in that said memory means stores the video signal every other horizontal scanning period.
Claim 5
Dependent Claim
23 words
A liquid crystal display device according to claim 1, characterized in that said memory means stores part of bits constituting said video signal.
Claim 6
Dependent Claim
25 words
A liquid crystal display device according to claim 5, characterized in that said memory means stores only the most significant bit of said video signal.
Claim 7
Dependent Claim
26 words
A liquid crystal display device according to claim 1, characterized in that said liquid crystal display panel means contains an STN-type liquid crystal display panel (17).
Claim 8
Dependent Claim
20 words
A liquid crystal display device according to claim 1, characterized in that said scanning means scans multiple scanning electrodes simultaneously.
Claim 9
Dependent Claim
57 words
A liquid crystal display device according to claim 1, characterized in that said scanning means contains a scanning electrode driving means (20, 21, 222, 223, 322, 323, 422, 423, 522, 523) provided for each group of said scanning electrodes, each scanning electrode driving means outputting the scanning signal for scanning the corresponding group of said scanning electrodes.
Claim 10
Dependent Claim
32 words
A liquid crystal display device according to claim 9, characterized in that each of said scanning electrode driving means (20, 21, 222, 223, 322, 323, 422, 423, 522, 523) operates in turns.
Claim 11
Dependent Claim
36 words
A liquid crystal display device according to claim 9, characterized in that each of said scanning electrode driving means (20, 21, 222, 223, 322, 323, 422, 423, 522, 523) drives a plurality of scanning electrodes simultaneously.
Claim 12
Dependent Claim
61 words
A liquid crystal display device according to claim 9, characterized in that said scanning means contains inhibiting means (22, 23, 222, 223, 322, 323, 422, 423, 522, 523) for permitting one of said plurality of scanning electrode driving means to output the scanning signal and at the same time, inhibiting the other scanning electrode driving means from outputting the scanning signal.
Claim 13
Dependent Claim
50 words
A liquid crystal display device according to claim 1, characterized in that said scanning means contains inhibiting means (22, 23, 222, 223, 322, 323, 422, 423, 522, 523) for inhibiting part of the scanning timing signals from being outputted from said timing signal generating means (12, 212, 312, 412, 512).
Claim 14
Dependent Claim
83 words
A liquid crystal display device according to claim 1, characterized in that: said memory means (M, M2, M3, M4, M5) stores at least the most significant bit of the video data supplied from said video data supplying means; and said selecting means (14, 214, 314, 414, 514) alternately outputs the video data containing at least the most significant bit supplied via said memory means (M, M2, M3, M4, M5) and the video signal supplied from said video signal supplying means every specified interval.
Claim 15
Dependent Claim
21 words
A liquid crystal display device according to claim 14, characterized in that said specified interval is a 1/2 horizontal scanning period.
Claim 16
Dependent Claim
75 words
A liquid crystal display device according to claim 1, characterized in that: the plurality of scanning electrodes (X) of said liquid crystal display panel means are divided into N groups; and scanning means (18-23, 222, 223, 322, 323, 422, 423, 522, 523) scans one of the scanning electrodes (X) N times during a single field interval, and with a single selection interval divided into N subintervals, selects said N groups of scanning electrodes in turns.
Claim 17
Dependent Claim
28 words
A liquid crystal display device according to claim 16, characterized in that during a single field interval, at least one selection interval differs in duration from the others.
Claim 18
Dependent Claim
77 words
A liquid crystal display device according to claim 1, characterized in that said signal electrode driving means (15, 16), during a single field, supplies to said signal electrodes the driving signals corresponding to the data containing at least the most significant bit of said image data having a plurality of bits at one scanning, whereas supplying to said signal electrodes (Y) the driving signals corresponding to the data not containing said most significant bit at another scanning.
Claim 19
Dependent Claim
34 words
A liquid crystal display device according to claim 18, characterized in that said signal electrode driving means (15, 16) contains means for rearranging the bits of said data not containing the most significant bit.
Claim 20
Dependent Claim
34 words
A liquid crystal display device according to claim 18, characterized in that said signal electrode driving means (15, 16) contains means (431-440) for rearranging the bits of said data containing the most significant bit.
Claim 21
Dependent Claim
42 words
A liquid crystal display device according to claim 20, characterized in that said signal electrode driving means (15, 16) further contains means (414) for adding the least significant bit of said image data to the data rearranged by said rearranging means (431-440).
Claim 22
Dependent Claim
65 words
A liquid crystal display device according to claim 1, characterized in that said video signal supplying means (11, 13) outputs video signal consisting of A bits, A being an integer more than 1, and said signal electrode driving means (15, 16) supplies to the signal electrodes (Y) the driving signals corresponding to the data having B bits, B being an integer smaller than A .
Claim 23
Dependent Claim
72 words
A liquid crystal display device according to claim 1, characterized in that said scanning means (18-23, 222, 223, 322, 323, 422, 423, 522, 523) receives the scanning timing signals generated at said timing signal generating means (12, 212, 312, 412, 512), and then supplies to said scanning electrodes (X) the scanning timing signals excluding at least the first and last timing signals for a single field, as the scanning electrode driving signals.
Claim 24
Dependent Claim
199 words
An image display device, wherein the scanning electrodes (X) of the image display panel means having a plurality of scanning electrodes and a plurality of signal electrodes are scanned by scanning means on the basis of the scanning timing signal generated by timing signal generating means, while said signal electrodes are supplied with the image data from an image data source by means of signal electrode driving means, characterized in that: said image data source (11, 13, 213, 313, 413, 513) supplies image data comprising of A bits, A being an integer more than 1; said scanning means (18, 19, 20, 21, 22, 23, 222, 223, 322, 323, 422, 423, 522, 523) scans said image display panel means (17) a plurality of times during a single field; and said signal electrode driving means (15, 16), during a single field, supplies to said signal electrodes the data comprising B bits obtained from said image data of A bits at one scanning, B being an integer smaller than A , whereas supplying to said signal electrodes (Y) the data of C bits obtained from said image data of A bits at another scanning, C being an integer smaller than A .
Claim 25
Dependent Claim
24 words
An image display device according to claim 24, characterized in that said B-bit data contains the most significant bit of said A-bit image data.
Claim 26
Dependent Claim
24 words
An image display device according to claim 24, characterized in that said C-bit data contains the most significant bit of said A-bit image data.
Claim 27
Dependent Claim
26 words
An image display device according to claim 24, characterized in that said C-bit data does not contains the most significant bit of said A-bit image data.
Claim 28
Dependent Claim
71 words
An image display device according to claim 24, characterized in that said scanning means (18-23, 222, 223, 322, 323, 422, 423, 522, 523) receives the scanning timing signals generated at said timing signal generating means (12, 212, 312, 412, 512), and then supplies to said scanning electrodes (X) the scanning timing signals excluding at least the first and last timing signals for a single field, as the scanning electrode driving signals.
References Cited (Backward Citations)
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