Liquid crystal display system capable of reducing and enlarging resolution of input display data

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a display system for use when display data output by a computer differs in resolution from that of a liquid crystal display screen which is to display the display data is used as a display for a personal computer, etc.

2. Description of the Related Art

A conventional liquid crystal display receives an interface signal containing display data and a timing signal output by a computer, converts the interface signal into a drive signal for the liquid crystal display, and feeds the drive signal into a liquid crystal drive means. The liquid crystal drive means converts the display data contained in the drive signal into a liquid crystal drive voltage corresponding to the display data and outputs the voltage to a liquid crystal panel. When receiving the liquid crystal drive voltage, the liquid crystal panel displays an image. If the input interface signal differs from the liquid crystal panel in resolution, for example, if the resolution of the input interface signal is larger than that of the liquid crystal panel, a part of the display data contained in the input interface signal is deleted to match the resolution of the interface signal with that of the liquid crystal panel, as described in Japanese Patent Laid-Open No. 57-115593. In the conventional example, the display object is limited to characters and space dots around a character are deleted for each kind of character. The part to be deleted needs to be specified for each kind of character.

The conventional example applies to characters and is not intended for displaying data other than characters.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a liquid crystal display system which can accept an interface signal having a resolution different from that of the liquid crystal display for displaying the display data contained in the interface signal regardless of the type of display data.

To this end, according to one aspect of the invention, there is provided a method of converting first display data in a raster scan format having a first resolution received from an external system into second display data for a liquid crystal display having a second resolution different from the first resolution, the method comprising the steps of:

a) generating data for n vertical or horizontal lines based on specific m vertical or horizontal lines contiguous to each other of the first display data, where m is an integer of two or greater and n is an integer less than m;

b) repeating at least one of the following steps c) and d) as many times as required in sequence at different positions on a screen of the liquid crystal display;

c) replacing k (n<k≦m) lines of the m vertical or horizontal lines with the n vertical or horizontal lines; and

d) adding the n vertical or horizontal lines to the m vertical or horizontal lines.

The data conversion means converts display data received from a personal computer or the like into display data using gray scale data so that it matches the resolution of the liquid crystal display. Thus, even display data output by the personal computer or the like assuming an output device having resolution different from that of the liquid crystal display can be displayed on the liquid crystal display.

According to another aspect of the invention, there is provided a method of converting first display data in a raster scan format having a first horizontal resolution received from an external system into second display data for a liquid crystal display having a second horizontal resolution smaller than the first horizontal resolution, the method comprising the steps of:

a) virtually dividing a set of M contiguous dots on a horizontal line into N equal partitions, where M is an integer of three or greater and N is an integer of two or more, less than M;

b) repeating, N times with respect to the N equal partitions, a weighted addition of data values of dots contained in one partition, depending upon what percentage of the partition is occupied by each dot in the partition;

c) replacing the M dots with n dots which have the data values of the N partitions resulting from the weighted additions in step b);

d) repeating steps a) to c) for different sets of M contiguous dots in sequence at least in a part of one horizontal line; and

e) repeating step d) for different horizontal lines in sequence.

According to still another aspect of the invention, there is provided a method of converting first display data in a raster scan format having first horizontal resolution received from an external system into second display data for a liquid crystal display having second horizontal resolution larger than the first horizontal resolution, the method comprising the steps of:

a) virtually dividing a set of M contiguous dots on a horizontal line into N equal partitions, where M is an integer of two or greater and N is an integer of three or more which is greater than M;

b) repeating, N times with respect to the N equal partitions, a weighted addition of one or more data values of dots contained in one partition, depending upon what percentage of each dot contributes in the partition;

c) replacing the M dots with N dots which have the data values of the N partitions resulting from the weighted additions in step b);

d) repeating steps a) to c) for different sets of M contiguous dots in sequence at least in a part of one horizontal line; and

e) repeating step d) for different horizontal lines in sequence.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1

is a block diagram of a system to which the invention is applied;

FIG. 2

is an illustration showing resolutions to which the invention may be applied;

FIG. 3

is an illustration of reduction and enlargement by gray scale line replacement and insertion according to the invention;

FIG. 4

is an illustration of a method for detecting an area with less display data;

FIGS. 5A and 5B

are illustrations of gray scale pixel calculation methods;

FIG. 6

is an illustration of replacement with a gray scale line using three extraction lines;

FIG. 7

is a block diagram showing the configuration of the data conversion section shown in

FIG. 1

;

FIG. 8

is a block diagram showing the configuration of a reduction process section shown in

FIG. 11

;

FIG. 9

is a block diagram of a DAD conversion system;

FIG. 10

is an illustration of DAD conversion operation of the system shown in

FIG. 9

;

FIG. 11

is a block diagram showing the configuration of the R data converter shown in

FIG. 7

;

FIG. 12

is a block diagram showing the configuration of the enlargement process section shown in

FIG. 11

;

FIG. 13

is an input/output timing chart for a lateral reduction process;

FIG. 14

is an input/output timing chart for a longitudinal reduction process;

FIG. 15

is an input/output timing chart for a lateral enlargement process;

FIG. 16

is an input/output timing chart for a longitudinal enlargement process;

FIG. 17

is a drawing representing the concept of lateral reduction in another embodiment of the invention;

FIG. 18

is an illustration of reduction by gray scale replacement related to

FIG. 17

;

FIG. 19

is a drawing representing the concept of lateral enlargement in another embodiment of the invention;

FIG. 20

is an illustration of enlargement by gray scale insertion related to

FIG. 19

;

FIG. 21

is an illustration of a method for detecting a line with less display data;

FIG. 22

is a block diagram showing the configuration of a data conversion section in another embodiment of the invention;

FIG. 23

is a block diagram showing the configuration of the R data converter shown in

FIG. 22

;

FIG. 24

is a block diagram showing the configuration of the reduction process section shown in

FIG. 23

;

FIG. 25

is a block diagram showing the configuration of the enlargement process section shown in

FIG. 23

;

FIG. 26

is an input/output timing chart for the lateral enlargement process;

FIG. 27

is an input/output timing chart for the lateral reduction process;

FIG. 28

is an input/output timing chart for the longitudinal reduction process;

FIG. 29

is an input/output timing chart for the longitudinal enlargement process;

FIG. 30

is a conceptual diagram of the reduction process executed in dot units;

FIG. 31

is a conceptual illustration of a system to which the invention is applied; and

FIG. 32

is a block diagram showing a liquid crystal display unit to which the invention is applied.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the invention will now be described with reference to the accompanying drawings.

A first embodiment of a personal computer system to which a liquid crystal display system of the invention is connected will be discussed with reference to

FIGS. 1

to

4

,

5

A-

5

B, and

6

to

16

.

FIG. 1

is a block diagram of a personal computer system to which the invention is applied. In the figure, numeral

1

indicates a personal computer or workstation (PC) which contains a central processing unit (CPU)

101

, etc., numeral

2

indicates display data, numeral

3

indicates a timing signal, numeral

4

indicates a data conversion section for converting display data of the PC

1

into a liquid crystal display signal, numeral

5

indicates liquid crystal display data, numeral

6

indicates a liquid crystal display timing signal, and numeral

7

indicates a liquid crystal panel. The data conversion section

4

and the liquid crystal panel

7

make up a liquid crystal display unit. The data conversion section

4

converts the display data

2

input from the PC

1

into the liquid crystal display data

5

enlarged or reduced in accordance with the resolution of the liquid crystal panel

7

and generates the liquid crystal display timing signal

6

. The liquid crystal display data

5

and the liquid crystal display timing signal

6

are collectively called a drive signal. The display data is converted into a liquid crystal drive voltage at the liquid crystal panel

7

. In the description to follow, assume that the display data

2

has 4-bit gradation data for each of the primary colors red (R), green (G), and blue (B) and is transferred in series in synchronization with the timing signal

3

. For simplicity, assume that the liquid crystal panel

7

consists of pixels of 1024×768 dots and that the PC

1

outputs timing signal and display data of 1120×780 dots, which will be hereinafter referred to as display mode

1

throughout the specification, or 640×480 dots, which will be hereinafter referred to as display mode

2

throughout the specification, in response to the display mode.

FIG. 2

shows the display modes of the invention. The data conversion section

4

discriminates between the display modes

1

and

2

and executes reduction processes in display mode

1

and enlargement processes in display mode

2

in response to the display mode.

Also, assume that the number of colors that can be displayed on the liquid crystal panel

7

is 4096 and that the PC

1

performs so-called raster scanning in which with each pixel represented by 4-bit attribute data (gradation data) for each of R (red), G (green), and B (blue), the data is output for one pixel at a time in sequence from left to right in the horizontal line direction and the operation is repeated in sequence as many times as the number of the horizontal lines from top to bottom.

Some operation examples of the data conversion section

4

will be discussed in the first embodiment.

As the first operation example, a gray scale line replacement/insertion system will be described with reference to FIG.

3

.

FIG. 3

shows gray scale line replacement in display mode

1

and insertion in display mode

2

, wherein numerals

8

and

9

indicate first and second horizontal extraction lines representing horizontal replacement or insertion positions, numerals

10

and

11

indicate first and second vertical extraction lines representing vertical replacement or insertion positions, numeral

12

indicates a horizontal gray scale line resulting from calculating the gray scale for the first and second horizontal extraction lines

8

and

9

, and numeral

13

indicates a vertical gray scale line resulting from calculating the gray scale for the first and second vertical extraction lines

10

and

11

. In display mode

1

, horizontal and vertical gray scale lines are prepared from first and second horizontal and vertical extraction lines and the first and second horizontal extraction lines

8

and

9

are replaced with the horizontal gray scale line

12

and the first and second vertical extraction lines

10

and

11

are replaced with the vertical gray scale line

13

, thereby performing reduction processing. In display mode

2

, a horizontal gray scale line is inserted between the horizontal extraction lines

8

and

9

and a vertical gray scale line is inserted between the vertical extraction lines

10

and

11

, thereby performing enlargement processing.

The extraction line positions may be equally spaced as desired, or lines with less display data may be found and selected to be extraction lines.

FIG. 4

shows a method of determining the position of a horizontal or vertical extraction line where replacement or insertion is to be made from the display data amount. In the figure, numeral

14

indicates the summation result of the number of pixels displayed in a color different from the background color for each vertical line, numeral

15

indicates the summation result of the number of pixels displayed in a color different from the background color for each horizontal line, and numeral

16

indicates a hatched area containing the positions of horizontal or vertical lines where insertion or deletion can be made, determined from the summation results

14

and

15

. In the example, positions having the smallest amount of display data possible are found for replacement or insertion positions.

Further, for a screen with windows displayed, an area outside the window regions may be detected for replacement or insertion positions.

FIGS. 5A and 5B

show a gray scale pixel calculation method.

For example, to prepare a gray scale pixel from two pixels shown in

FIG. 5A

, the average values of the attributes for R, G, and B may be calculated:

R′=(R0+R1)/2

G′=(G0+G1)/2 Expression 1

B′=(B0+B1)/2

This calculation can be repeated as many times as the number of pixels making up one line for calculating a gray scale line. Further, to calculate the gray scale from a number of pixels as shown in

FIG. 5B

, such as at the intersection of horizontal and vertical lines, the average of the attributes for the four pixels

R′=(R0+R1+R2+R3)/4

G′=(G0+G1+G2+G3)/4 Expression 2

B′=(B0+B1+B2+B3)/4

may be used as gray scale pixel data.

When the average values are calculated, fractional digits may occur. It is desirable to handle the fractional digits so that a color different from the background color is output in response to the attribute of the background color. For example, if the background is black (R=0000, G=0000, B=0000), when the average values of R, G, and B are calculated, fractions are rounded up or rounded off, and if the background is white (R=1111, G=1111, B=1111), fractions are rounded down, whereby a color different from the background color can be displayed. If the background color has different attributes for R, G, and B, such as blue (R=0000, (G=0000, B=1111), fractions are rounded up when gradation of R or G is calculated, or fractions are rounded down when gradation of B is calculated.

Further, another system in which the number of extraction lines in the reduction process is three will be discussed with reference to FIG.

6

. Here, the processing is described by taking only horizontal lines as an example and similar processing is also performed for the vertical lines.

In

FIG. 6

, numerals

17

,

18

, and

19

indicate first, second, and third extraction lines and numeral

20

indicates a gray scale line found from the average of the display data for the three lines. The second extraction line

18

is replaced with the gray scale data line

20

and the third extraction line

19

is deleted, thereby performing the reduction process. Since similar processing is also performed in the vertical direction, the average of 9-pixel display data may be calculated for the intersection of the extraction lines.

The way to find the gray scale data is similar to that in the first operation example.

Next, an example of the hardware configuration of the data conversion section

4

for carrying out the first operation example will be discussed with reference to

FIGS. 7 and 8

.

FIG. 7

is an example of the configuration of the data conversion section

4

, wherein numerals

21

,

22

, and

23

indicate R display data, G display data, and B display data of the display data

2

respectively, numeral

24

indicates an R data converter, numeral

25

indicates a G data converter, numeral

26

indicates a B data converter, numeral

27

indicates B liquid crystal display data, numeral

28

indicates G liquid crystal display data, numeral

29

indicates R liquid crystal display data, numeral

51

indicates a display mode determination section, numeral

52

indicates a display mode signal, numeral

30

indicates a liquid crystal display timing signal generator, and numeral

6

indicates a liquid crystal display timing signal. The display mode determination section

51

determines the display mode from the timing signal

3

and outputs the display mode signal

52

. The data converters

24

,

25

, and

26

process the R, G, and B display data

21

,

22

, and

23

respectively in accordance with the resolution represented by the display mode signal

52

. The liquid crystal display timing signal generator

30

generates the liquid crystal display timing signal

6

matched with the output resolution represented by the display mode signal

52

from the timing signal

3

.

FIG. 11

is an example of the configuration of the R data converter

24

. The G and B data converters

25

and

26

also each have the same configuration as the R data converter

24

. In

FIG. 11

, numeral

53

indicates a reduction process section, numeral

54

indicates an enlargement process section, numeral

55

indicates reduced display data, numeral

56

indicates enlarged display data, and numeral

57

indicates resolution switch means. When the display mode signal

52

represents the display mode

1

, the reduction process section

53

converts the R display data

21

into the reduced display data

55

; at that time, the enlargement process section

54

does not operate. When the display mode signal

52

represents the display mode

2

, the enlargement process section

54

converts the R display data

21

into the enlarged display data

56

; at that time, the reduction process section

53

does not operate. The resolution switch means

57

is responsive to the display mode signal

52

for outputting the reduced display data

55

when the display mode signal

52

represents the display mode

1

or the enlarged display data

56

when the display mode signal

52

represents the display mode

2

as the R liquid crystal display data

29

. Although the reduction process section

53

and the enlargement process section

54

are provided to support two display modes in the embodiment, additional reduction or enlargement process sections can also be provided for supporting other resolutions.

FIG. 8

is one example of the configuration of the reduction process section

53

. Hereinafter, a horizontal row of dots of display data will be referred to as a line. This means that the liquid crystal panel

7

used in the invention consists of 1024 dots×768 lines.

In

FIG. 8

, numeral

32

indicates a latch, numeral

33

indicates preceding dot data, numeral

34

indicates a horizontal operation section, numeral

35

indicates horizontal gray scale data, numeral

36

indicates a horizontal selector, numeral

37

indicates horizontal data, numeral

38

indicates a line memory, numeral

39

indicates a vertical selector, numeral

40

indicates preceding line data, numeral

41

indicates operational horizontal data, numeral

42

indicates a vertical operation section, numeral

43

indicates vertical gray scale data, numeral

44

indicates output horizontal data, and numeral

45

indicates an output selector. The latch

32

, which latches the R display data

21

in synchronization with a dot clock (not shown) provided by the timing signal

3

, outputs the preceding dot data

33

which is display data one dot before the R display data

21

. The horizontal operation section

34

performs an operation on the preceding dot data

33

and the R display data

21

(averaging them) and outputs the horizontal gray scale data

35

. The horizontal selector

36

selects either the horizontal gray scale data

35

or the R display data

21

depending on which position of the liquid crystal panel

7

the R display data

21

is at, and outputs the data

35

or

21

as the horizontal data

37

, as described below in detail.

The line memory

38

stores one line of the horizontal data

37

and outputs it as the preceding line data

40

which is data one line before when the display data of the next line is input. The vertical selector

39

outputs the horizontal data

37

to either the vertical operation section

42

as the operational horizontal data

41

or the output selector

45

as the output horizontal data

44

depending on which position of the liquid crystal panel

7

the horizontal data

37

is at, as described below in detail. The vertical operation section

42

performs an operation on the preceding line data

40

and the operational horizontal data

41

and outputs the result as the vertical gray scale data

43

. The output selector

45

outputs either the vertical gray scale data

43

or the output horizontal data

44

depending on which position of the liquid crystal panel

7

the R display data

21

is at, as with the R liquid crystal display data

29

, as described below in detail.

FIG. 12

is an example of the configuration of the enlargement process section

54

, wherein numeral

58

indicates a gray scale data frame memory, numeral

59

indicates a display data frame memory, numeral

60

indicates gray scale read data, and numeral

61

indicates display read data. Other components identical with those of the reduction process section

53

previously described with reference to

FIG. 8

are denoted by the same reference numerals in FIG.

12

. In

FIG. 12

, a latch

32

and a horizontal operation section

34

operate like those of the reduction process section

53

. If R display data

21

is data on a first vertical extraction line, a horizontal selector

36

outputs the R display data

21

, then outputs gray scale horizontal data

35

for inserting a vertical line before R display data

21

for the next dot comes. A line memory

38

, a vertical selector

39

, and a vertical operation section

42

operate like those of the reduction process section

53

. Vertical gray scale data

43

for one screen (frame) is stored in the gray scale data frame memory

58

and output horizontal data

44

for one screen (frame) is stored in the display data frame memory

59

. When display data of the next screen (frame) is input, the vertical gray scale read data

60

is read and inserted into any position between the display read data

61

for inserting a horizontal line.

Next, the operation related to the reduction process by gray scale replacement will be discussed in detail with reference to

FIGS. 1

,

7

,

8

, and

11

.

In

FIG. 1

, the data conversion section

4

converts the display data

2

and the timing signal

3

into the liquid display data

5

and the liquid crystal display timing signal

6

matched with the liquid crystal panel

7

for output. In

FIG. 7

, the display mode determination section

51

determines the display mode from the timing signal

3

and the display mode signal

52

matched with the resolution of the liquid crystal panel

7

for display. The display mode can be determined by counting the number of clocks of the timing signal

3

or by feeding the display mode signal

52

from an external system without providing the display mode determination section

51

. R, G, and B of the display data

2

are input to the R, G, and B data converters

24

,

25

, and

26

respectively, which then convert the data into the liquid crystal display data

5

matched with the display mode represented by the display mode signal

52

. The liquid crystal display timing signal generator

30

generates the liquid crystal display timing signal

6

matched with the display mode represented by the display mode signal

52

from the timing signal

3

.

The operation of the R data converter

24

for display data conversion will be discussed in detail with reference to FIG.

11

. Each of the G and B data converters

25

and

26

performs an operation similar to that of the R data converter

24

.

In

FIG. 11

, when the display mode signal

52

represents the display mode

1

, the reduction process section

53

operates and generates the reduced display data

55

. When the display mode signal

52

represents the display mode

2

, the enlargement process section

54

operates and generates the enlarged display data

56

. The resolution switch means

57

is responsive to the display mode signal

52

for selecting and outputting the reduced display data

55

in the display mode

1

or the enlarged display data

56

in the display mode

2

. As described above, additional reduction and enlargement process sections can be provided to make up a data conversion section which supports other resolutions.

The operation of the reduction process section

53

will be discussed in detail with reference to

FIGS. 8

,

13

, and

14

. In

FIG. 8

, since the latch

32

latches input R display data

21

according to a dot clock, the data output by the latch

32

becomes the preceding dot display data

33

which is the data one dot before the R display data

21

. The horizontal operation section

34

performs an operation on the preceding dot display data

33

and the R display data

21

to generate gray scale data, and outputs it as the horizontal gray scale data

35

. If the R display data

21

is data on a first vertical extraction line, the horizontal selector

36

outputs neither the horizontal gray scale data

35

nor the R display data

21

; if it is data on a second vertical extraction line, the horizontal selector

36

outputs the horizontal gray scale data

35

; if it is not data on the first or second vertical extraction line, the horizontal selector

36

outputs the R display data

21

as the horizontal data

37

.

The horizontal data

37

for one line is stored in the line memory

38

, and is read out when horizontal data

37

for the next line is input. Therefore, the data output by the line memory

38

becomes the preceding line display data

40

which is one line before the horizontal data

37

. If the horizontal data

37

is data on a first horizontal extraction line, the vertical selector

39

does not output the data to the vertical operation section

42

or the output selector

45

; if it is data on a second horizontal extraction line, the vertical selector

39

outputs the data to the vertical operation section

42

as the operational horizontal data

41

; if it is not data on the first or second vertical extraction line, the vertical selector

39

outputs the data to the output selector

45

as the output horizontal data

44

. The vertical operation section

42

performs an operation on the preceding line display data

40

and the operational horizontal data

41

to generate gray scale data, and outputs it as the vertical gray scale data

43

. If the horizontal data

37

is data on the first horizontal extraction line, the output selector

45

outputs neither the vertical gray scale data

43

nor the output horizontal data

44

; if it is data on the second horizontal extraction line, the output selector

45

outputs the vertical gray scale data

43

; if it is not data on the first or second horizontal extraction line, the output selector

45

outputs the output horizontal data

44

. The reduction process by gray scale replacement shown in

FIG. 3

is now complete.

FIG. 13

is an input/output timing chart for the lateral reduction process in the reduction process section

53

.

In the figure, numeral

101

indicates the input timing of the R display data

21

, numeral

102

indicates the output timing for the preceding dot data

33

, and numeral

103

indicates the output timing for the horizontal gray scale data

35

, showing that the result of dividing the sum of the R display data

21

and the preceding dot data

33

by two is output as the horizontal gray scale data

35

. Numeral

104

indicates the select signal timing of the horizontal selector

36

and numeral

105

indicates the output timing of horizontal data

37

, showing that the select signal

104

is set to 1 at the position next to the first vertical extraction line

10

shown in

FIG. 3

, outputting the horizontal gray scale data

35

. Numeral

106

indicates the timing of a synchronous clock contained in the liquid crystal timing signal

6

and numeral

107

indicates the timing of data displayed on the liquid crystal panel

7

. X

2

data is deleted by synchronizing the horizontal data timing

105

with the synchronous clock timing

106

for stopping the clock finally corresponding to the position of the first vertical extraction line

10

.

FIG. 14

is an input/output timing chart for the longitudinal reduction process of the reduction process section

53

.

In the figure, numeral

108

indicates the line output timing for the horizontal data

37

, numeral

109

indicates the output timing for the preceding line signal

40

output by the line memory

38

, numeral

110

indicates the output timing for the vertical gray scale data

43

generated by performing an operation on the output of the line memory

38

and the horizontal data

37

, and numeral

112

indicates the output timing of the reduced display signal

55

output from the output selector

45

. L

0

and L

1

denote data for the first line and data for the second line respectively; L

0

and L

1

are averaged to generate the vertical gray scale data

43

. This also applies to the second line, third line, and later. Numeral

111

indicates a select signal for the output selector

45

, which allows the vertical gray scale data

43

to be output on the line next to the first horizontal extraction line

8

shown in FIG.

3

. Numeral

112

indicates the output timing of the reduced display signal

55

, numeral

113

indicates the output timing of a horizontal synchronizing signal contained in the liquid crystal display timing signal

6

, and numeral

114

indicates the timing of display data actually displayed. Although the output timing

112

of the output selector

45

follows the select signal timing

111

, L

1

is not displayed as shown in

114

because the actual horizontal synchronizing signal is as shown in

113

Next, the enlargement process by gray scale insertion will be discussed in detail with reference to

FIGS. 12

,

15

, and

16

.

In

FIG. 12

, the latch

32

and the horizontal operation section

34

operate like those of the reduction process section

53

. If R display data

21

is data on a first vertical extraction line, the horizontal selector

36

outputs the R display data

21

, then outputs gray scale horizontal data

35

for inserting a vertical line before R display data

21

for the next dot comes. The line memory

38

, the vertical selector

39

, and the vertical operation section

42

operate like those of the reduction process section

53

. Vertical gray scale data

43

for one screen (frame) is stored in the gray scale data frame memory

58

and output horizontal data

44

for one screen (frame) is stored in the display data frame memory

59

. When display data for the next screen (frame) is input, the vertical gray scale read data

60

is read and inserted into any position between the display read data

61

for inserting a horizontal line.

FIG. 15

is an input/output timing chart of the lateral enlargement process for the enlargement process section

54

.

In the figure, numeral

115

indicates the input timing for the R display data

21

, numeral

116

indicates the output timing for the preceding dot data

33

, and numeral

117

indicates the output timing for the horizontal gray scale data

35

, showing that the result of dividing the sum of the R display data

21

and the preceding dot data

33

by two is output as the horizontal gray scale data

35

. Numeral

118

indicates the select signal timing for the horizontal selector

36

, numeral

119

indicates the output timing for the horizontal data

37

, and numeral

120

indicates the timing of a synchronous clock contained in the liquid crystal display timing signal

6

, showing that the select signal

104

is set to 1 at the position next to the first vertical extraction line

10

shown in

FIG. 3

, outputting the horizontal gray scale data

35

. The period of only the synchronous clock at the time is doubled and while 1-dot data is input, 2-dot data of the horizontal gray scale data

35

and the R display data

21

is output.

FIG. 16

is an input/output timing chart of the longitudinal enlargement process for the enlargement process section

54

.

In the figure, numeral

1119

indicates the output timing for the horizontal data

37

for each line, numeral

1120

indicates the output timing for the preceding line data

40

for each line output from the line memory

38

, and numeral

121

indicates the output timing of vertical gray scale data

43

for each line, showing that the vertical gray scale data

43

is the result of dividing by two the sum of the horizontal data

37

and the preceding line data

40

which is the data one line before the horizontal data

37

. Numeral

122

indicates a timing signal representing the position into which the vertical gray scale data

43

is inserted, numeral

123

indicates a horizontal synchronizing signal contained in the liquid crystal display timing signal

6

, and numeral

124

indicates the timing for each line actually displayed. When the vertical gray scale data is inserted, the vertical gray scale data insertion timing

122

is set to “1” on the line next to the first horizontal extraction line

8

. At this time, the period of the synchronous clock is doubled and while 1-line data is input, 2-line data is output. For the first one of these two lines, the vertical gray scale data is selectively output from the gray scale data frame memory

58

and for the second line, the horizontal data is selectively output from the display data frame memory

59

.

When a number of insertion lines are equally spaced, for example, when a gray scale data line is to be inserted every n lines, (n+1) line memories are provided for storing gray scale data to be inserted and line data. When the next data is input, the (n+1)-line data containing the gray scale line data is read out while n-line data is stored, whereby a horizontal line can be inserted without providing the frame memories.

The data conversion section

4

which performs the processing may be software which uses the CPU

101

, hardware, may exist in the PC

1

, or may be contained in the liquid crystal panel

7

.

As the second operation example of the data conversion section

4

, a system of converting horizontal resolution with low-pass filters will be described with reference to FIG.

9

.

FIG. 9

shows the configuration of an R data converter

24

with a low-pass filter, wherein numeral

46

is a D/A converter, numeral

47

indicates analog R display data, numeral

48

indicates a low-pass filter, numeral

49

indicates smoothed R display data, numeral

50

indicates an A/D converter, and numeral

51

indicates a display mode determination section which performs the same operation as that described above. The D/A converter

46

immediately converts digital output R display data

21

into analog R display data

47

and outputs the analog R display data

47

to the low-pass filter

48

which then smooths the data

47

to generate the smoothed R display data

49

. Lastly, the smoothed R display data is restored to a digital signal by the A/D converter

50

using the liquid crystal display timing signal

6

matched with the resolution of the liquid crystal display. If the liquid crystal display timing signal

6

has a higher frequency than the input timing signal

3

, the enlargement process is executed; if the former has lower frequency than the latter, the reduction process is executed.

FIG. 10

shows a signal conversion example of display data in the enlargement process.

Since the liquid crystal display timing signal

6

having higher frequency than the input timing signal

3

is used, enlarged R liquid crystal display data

29

is generated.

We have discussed the enlargement/reduction techniques as execution of the enlargement or reduction process so that the display data output from the PC

1

is made the same as the liquid crystal panel in resolution directly, but a technique which employs step-by-step execution of the enlargement or reduction process may be used. For example, to convert display data represented by 640×480 dots into 1120×780 dots, first the display data is first enlarged to 1280×960 dots, which is twice 640×480 dots, then the enlarged displayed data is reduced to 1120×780 dots. If an attempt is made to enlarge the display data directly to 1120×780 dots, it takes time because of a large number of insertion lines. However, it does not take much time to enlarge the display data to 1280×960 equivalent to a double of 640×480 dots because of simple processing, and then only a few lines need to be removed. Therefore, the entire processing can be performed at high speed.

In contrast, if the resolution of the liquid crystal panel

7

in

FIG. 1

is 640×480 dots and display data of 1120×780 dots is output from the PC

1

, the enlargement process can be simply the reverse of the reduction process, which makes the processing fast.

In the invention, how the resolution should be adjusted can be determined automatically by providing means for determining what resolution the display data supplied to the liquid crystal display has, such as means for determining resolution from the timing signal input from the computer.

Another embodiment of a personal computer system to which a liquid crystal display system of the invention is connected will be discussed with reference to

FIGS. 17

to

30

.

The system configuration of another embodiment is the same as that shown in

FIG. 1

except for the data conversion section

4

.

Some operation examples of the data conversion section

4

will be discussed in another embodiment.

As the first operation example, a gradation integration/reduction system will be described with reference to FIG.

17

.

FIG. 17

shows the concept of the lateral reduction method in display mode

1

(1120×780 dots). Here, the reduction of five pixels to four pixels is discussed, and

FIG. 17

represents R, G, or B color data.

In

FIG. 17

, numeral

8

indicates 5-pixel display data and numeral

9

indicates 4-pixel display data after reduction. The vertical axis is entered with 1 as the highest intensity and 0 as the lowest intensity and the horizontal axis is entered as pixel positions. To reduce the 5-pixel data

8

to the 4-pixel data

9

, the 5-pixel width is virtually quartered, namely, the 1-pixel width is widened one-quarter and display data of five-quarter pixel width is converted into display data of 1-pixel width. Therefore, the calculation expression for the 1-pixel display data is

X(0,0)′=(X(0,0)×4+X(0,1)×1)/5

X(0,1)′=(X(0,1)×3+X(0,2)×2)/5

X(0,2)′=(X(0,2)×2+X(0,3)×3)/5

X(0,3)′=(X(0,3)×1+X(0,4)×4)/5 Expression 3

where X (0, 0) to X (0, 4) are gray scale data for the first to fifth pixels before reduction and X (0, 0)′ to X (0, 3)′ are gray scale data for the first to fourth pixels after reduction, wherein the first digit represents the line number and the second digit represents the pixel number. That is, X (0, 0) is gray scale data for the first pixel of the first line and that X (0, 1) is gray scale data for the second pixel of the first line. Since the description assumes that 1120 pixels are reduced to 1024 pixels, 35 pixels are reduced to 32 pixels from 1024/1120=32/35. The calculation expression is:

X(0,0)′=(X(0,0)×32+X(0,1)×3)/35

X(0,1)′=(X(0,1)×29+X(0,2)×6)/35

X(0,2)′=(X(0,2)×26+X(0,3)×9)/35

X(0,3)′=(X(0,3)×23+X(0,4)×12)/35

X(0,4)′=(X(0,4)×20+X(0,5)×15)/35

X(0,5)′=(X(0,5)×17+X(0,6)×18)/35

X(0,6)′=(X(0,6)×14+X(0,7)×21)/35

X(0,7)′=(X(0,7)×11+X(0,8)×24)/35

X(0,8)′=(X(0,8)×8+X(0,9)×27)/35

X(0,9)′=(X(0,9)×5+X(0,10)×30)/35

X(0,10)′=(X(0,10)×2+X(0,11)×32+X(0,12)×1)/35

X(0,11)′=(X(0,12)×31+X(0,13)×4)/35

X(0,12)′=(X(0,13)×28+X(0,14)×7)/35

X(0,13)′=(X(0,14)×25+X(0,15)×10)/35

X(0,14)′=(X(0,15)×22+X(0,16)×13)/35

X(0,15)′=(X(0,16)×19+X(0,17)×16)/35

X(0,16)′=(X(0,17)×16+X(0,18)×19)/35

X(0,17)′=(X(0,18)×13+X(0,19)×22)/35

X(0,18)′=(X(0,19)×10+X(0,20)×25)/35

X(0,19)′=(X(0,20)×7+X(0,21)×28)/35

X(0,20)′=(X(0,21)×4+X(0,22)×31)/35

X(0,21)′=(X(0,22)×1+X(0,23)×32+X(0,24)×2)/35

X(0,22)′=(X(0,24)×30+X(0,25)×5)/35

X(0,23)′=(X(0,25)×27+X(0,26)×8)/35

X(0,24)′=(X(0,26)×24+X(0,27)×11)/35

X(0,25)′=(X(0,27)×21+X(0,28)×14)/35

X(0,26)′=(X(0,28)×18+X(0,29)×17)/35

X(0,27)′=(X(0,29)×15+X(0,30)×20)/35

X(0,28)′=(X(0,30)×12+X(0,31)×23)/35

X(0,29)′=(X(0,31)×9+X(0,32)×26)/35

X(0,30)′=(X(0,32)×6+X(0,33)×29)/35

X(0,31)′=(X(0,32)×3+X(0,34)×32)/35 Expression 4

where X (0, 0) to X (0, 34) are gray scale data for the first to 35th pixels before reduction and X (0, 0)′ to X (0, 31)′ are gray scale data of the first to 32nd pixels after reduction. Similar operations can also be performed in the longitudinal direction. However, to use a similar method for longitudinal processing, a memory for a plurality of lines would be required, which would increase the size of the circuit. Thus, the following processing can also be carried out so as not to increase the circuit scale:

FIG. 18

shows reduction by gray scale replacement wherein a longitudinal reduction method is also shown.

To reduce 780 lines to 768 lines in the longitudinal direction, the deletion of 12 lines is required. In

FIG. 18

, numeral

210

indicates an extraction line to be deleted and numeral

211

indicates a replacement line after reduction. Longitudinal reduction is executed by replacing the extraction line

210

and the following line with the replacement line

211

which is the gray scale of the extraction line

210

and the following line. Therefore, pixels, other than the replacement line

211

, to which “′” is attached are pixels reduced using Expression 4 in the lateral direction, and to process the extraction line

210

and the following line using Expression 4 and average these two lines, the replacement line

211

is

X(2,0)′=(X(2,0)×32+X(3,0)×32+X(2,1)×3+X(3,1)×3)/70

X(2,1)′=(X(2,1)×29+X(3,1)×29+X(2,2)×6+X(3,2)×6)/70

X(2,2)′=(X(2,2)×26+X(3,2)×26+X(2,3)×9+X(3,3)×9)/70

X(2,3)′=(X(2,3)×23+X(3,3)×23+X(2,4)×12+X(3,4)×12)/70

X(2,4)′=(X(2,4)×20+X(3,4)×20+X(2,5)×15+X(3,5)×15)/70

X(2,5)′=(X(2,5)×17+X(3,5)×17+X(2,6)×18+X(3,6)×18)/70

X(2,26)′=(X(2,28)×18+X(3,28)×18+X(2,29)×17+X(3,29)×17)/70

X(2,27)′=(X(2,29)×15+X(3,29)×15+X(2,30)×20+X(3,30)×20)/70

X(2,28)′=(X(2,30)×12+X(3,30)×12+X(2,31)×23+X(3,31)×23)/70

X(2,29)′=(X(2,31)×9+X(3,31)×9+X(2,32)×26+X(3,32)×26)/70

X(2,30)′=(X(2,32)×6+X(3,32)×6+X(2,33)×29+X(3,33)×29)/70

X(2,31)′=(X(2,33)×3+X(3,33)×3+X(2,34)×32+X(3,34)×32)/70 Expression 5

Data for the two lines (third and fourth lines) of the extraction lines is calculated. This method would require a 1-line memory, as described below in detail.

FIG. 19

shows the concept for the lateral enlargement method in display mode

2

(640×480 dots). Here, enlargement of four pixels to five pixels is discussed.

In

FIG. 19

, numeral

212

indicates 4-pixel display data and numeral

213

indicates 5-pixel display data after enlargement.

The vertical axis is entered with 1 as the highest intensity and 0 as the lowest intensity and the horizontal axis is entered as pixel positions. To enlarge the 4-pixel data

212

to the 5-pixel data

213

, the 4-pixel width is divided into five equal parts, namely, the 1-pixel width is narrowed by one-fifth and display data of four-fifth pixel width is converted into display data of 1-pixel width. Therefore, the 1-pixel display data is expressed by

X(0,0)′=(X(0,0)×4)/4

X(0,1)′=(X(0,0)×1+X(0,1)×3)/4

X(0,2)′=(X(0,1)×2+X(0,2)×2)/4

X(0,3)′=(X(0,2)×3+X(0,3)×1)/4

X(0,4)′=(X(0,3)×4)/4 Expression 6

where data to which “′” is attached is gray scale data after processing. In fact, to enlarge 640 pixels to 1024 pixels, five pixels are enlarged to eight pixels from 1024/640=8/5. This is expressed by

X(0,0)′=(X(0,0)×5)/5

X(0,1)′=(X(0,0)×3+X(0,1)×2)/5

X(0,2)′=(X(0,1)×5)/5

X(0,3)′=(X(0,1)×1+X(0,2)×4)/5

X(0,4)′=(X(0,2)×4+X(0,3)×1)/5

X(0,5)′=(X(0,3)×5)/5

X(0,6)′=(X(0,3)×2+X(0,4)×3)/5

X(0,7)′=(X(0,4)×5)/5 Expression 7

Like the reduction process, to use a similar method for longitudinal processing, a memory for a plurality of lines would be required, which would increase the size of the circuit. Thus, the following processing can also be performed so as not to increase the circuit scale.

FIG. 20

shows enlargement by gray scale insertion wherein a longitudinal enlargement method is also shown. To enlarge 480 lines to 768 lines in the longitudinal direction, the insertion of 288 lines is required. In

FIG. 20

, numerals

214

and

215

indicate extraction lines to represent the insertion position and numeral

216

indicates an insertion line after enlargement. Longitudinal enlargement is executed by inserting the insertion line

216

which is a gray scale for the extraction lines

214

and

215

between the extraction lines

214

and

215

. Therefore, the pixels, other than the insertion line

216

, to which “′” is attached are pixels enlarged using Expression 4 in the lateral direction, and to process the extraction lines

214

and

215

using Expression 4 and average these two lines, the insertion line

216

is

X(3,0)′=(X(2,0)×5+X(3,0)×5)/10

X(3,1)′=(X(2,0)×3+X(3,0)×3+X(2,1)×2+X(3,1)×2)/10

X(3,2)′=(X(2,1)×5+X(3,1)×5)/10

X(3,3)′=(X(2,1)×1+X(3,1)×1+X(2,2)×4+X(3,2)×4)10

X(3,4)′=(X(2,2)×4+X(3,2)×4+X(2,3)×1+X(3,3)×1)/10

X(3,5)′=(X(2,3)×5+X(3,3)×5)/10

X(3,6)′=(X(2,3)×2+X(3,3)×2+X(2,4)×3+X(3,4)×3)/10

X(3,7)′=(X(2,4)×5+X(3,4)×5)/10 Expression 8

Data for two lines is calculated. The calculation is executed for each color, thereby converting the display data.

As described above, the calculation is executed separately for each of R, G, and B. At that time, fractional digits may occur. To clarify the difference between the background color and text and graphics colors, it is desirable to handle the fractional digits so that a color different from the background color is output in response to the attributes of the background color. For example, if the background is black (R=0000, G=0000, B=0000), when the average values of R, G, and B are calculated, fractions are rounded up or rounded off, and if the background is white (R=1111, G=1111, B=1111), fractions are rounded down, whereby a color different from the background color can be displayed. If the background color has different R, G, and B attributes such as blue (R=0000, G=0000, B=1111), fractions are rounded up when gradation of R or G is calculated, or fractions are rounded down when gradation of B is calculated.

The extraction line positions in longitudinal reduction or enlargement may be equally spaced as desired, or lines with less display data may be found and set to extraction lines.

Like

FIG. 4

,

FIG. 21

shows a method of determining the position of a horizontal or vertical extraction line where replacement or insertion is to be made from the display data amount, wherein only a horizontally extending area is detected. In

FIG. 21

, numeral

217

indicates the summation result of the number of pixels displayed in a color different from the background color for each horizontal line and numeral

218

indicates positions of horizontal lines where insertion or deletion can be made, determined from the summation result

217

. In the example, positions having as little display data as possible are found for replacement or insertion positions. For a screen with windows displayed, an area outside the window regions may be detected for replacement or insertion positions.

Next, an example of the hardware configuration of the data conversion section

4

for carrying out the first operation example shown in

FIG. 17

will be discussed.

FIG. 22

is a configuration example of the data conversion section

4

, wherein numerals

219

,

220

, and

221

indicate R display data, G display data, and B display data of display data

2

respectively, numeral

222

indicates an R data converter, numeral

223

indicates a G data converter, numeral

224

indicates a B data converter, numeral

225

indicates R liquid crystal display data, numeral

226

indicates G liquid crystal display data, numeral

227

indicates B liquid crystal display data, numeral

81

is a display position determination section, numeral

82

is a lateral display position signal, numeral

83

is a longitudinal display position signal, numeral

228

indicates a display mode determination section, numeral

229

indicates a display mode signal, and numeral

230

indicates a liquid crystal display timing signal generator. The display position determination section

81

determines the display position of each pixel of the display data

2

from a timing signal

3

and outputs the lateral position as the lateral display position signal

82

and the longitudinal position as the longitudinal display position signal

83

. The display mode determination section

228

determines the display mode from the timing signal

3

and outputs the display mode signal

229

. The data converters

222

,

223

, and

224

process the R, G, and B display data

219

,

220

, and

221

respectively in accordance with the resolution represented by the display mode signal

229

and the display position indicated by the lateral and longitudinal display position signals

82

and

83

. The liquid crystal display timing signal generator

230

generates a liquid crystal display timing signal

6

matched with the output resolution represented by the display mode signal

229

from the timing signal

3

.

FIG. 23

is an example of the configuration of the R data converter

222

. The G and B data converters

223

and

224

also each have the same configuration as the R data converter

24

.

In

FIG. 23

, numeral

231

indicates a reduction process section, numeral

232

indicates an enlargement process section, numeral

233

indicates reduced display data, numeral

234

indicates enlarged display data, and numeral

235

indicates a resolution switch means. When the display mode signal

229

represents the display mode

1

, the reduction process section

231

converts the R display data

219

into the reduced display data

233

in response to the lateral display position signal

82

and longitudinal display position signal

83

; at that time, the enlargement process section

232

does not operate. When the display mode signal

229

represents the display mode

2

, the enlargement process section

232

converts the R display data

219

into the enlarged display data

234

in response to the lateral display position signal

82

and longitudinal display position signal

83

; at that time, the reduction process section

231

does not operate. The resolution switch means

235

is responsive to the display mode signal

229

for outputting the reduced display signal

233

when the signal

229

represents the display mode

1

or the enlarged display signal

234

when the signal

229

represents the display mode

2

as the R liquid crystal display signal

225

. Although the reduction process section

231

and the enlargement process section

232

are provided to support two display modes in the embodiment, additional reduction or enlargement process sections can also be provided for supporting other resolutions.

FIG. 24

is one example of the configuration of the reduction process section

231

. As described above, a horizontal row of pixels of display data is referred to as a line. This means that the liquid crystal panel

7

used in the invention consists of 1024 pixels×768 lines and that the display mode

1

provides 1120 pixels×780 lines.

In

FIG. 24

, numeral

236

indicates a pre-preceding dot data latch, numeral

237

indicates a preceding dot data latch, numeral

238

indicates pre-preceding dot data, numeral

239

indicates preceding dot data, numeral

240

indicates a lateral operation section, numeral

241

indicates laterally reduced data, numeral

242

indicates a line memory, numeral

243

indicates preceding line data, numeral

244

indicates a longitudinal operation section, numeral

245

indicates longitudinal gray scale data and numeral

246

indicates an output selector. The preceding dot data latch

237

, which latches the R display data

219

in response to a dot clock, outputs the preceding dot data

239

which is display data one pixel before the R display data

219

. The pre-preceding dot data latch

236

, which latches the preceding dot data

239

in response to a dot clock, outputs the pre-preceding dot data

238

which is display data two pixels before the R display data

219

. The lateral operation section

240

performs an operation on the R display data

219

and the preceding dot data

239

, the pre-preceding dot data

238

according to Expression 4 in response to the lateral display position signal

82

depending on which pixel position of the liquid crystal panel

7

the R display data

219

is at, and outputs the result as the laterally reduced data

241

, as described below in detail. The line memory

242

stores one line of the laterally reduced data

241

and outputs as the preceding line data

243

which is data one line before when the R display data

219

of the next line is input. The longitudinal operation section

244

performs an operation on the laterally reduced data

241

and the preceding line data

243

in response to the longitudinal display position signal

83

depending on which line position of the liquid crystal panel

7

the R display data

219

is at, and outputs the result as the longitudinal gray scale data

245

, as described below in detail. The output data selector

246

selects the laterally reduced data

241

or the longitudinal gray scale data

245

and outputs or does not output them in response to the longitudinal display position signal

83

, as described in detail below.

FIG. 25

is an example of the configuration of the enlargement process section

232

, wherein numeral

247

indicates laterally enlarged data, numeral

248

indicates a gray scale data frame memory, numeral

249

indicates a display data frame memory, numeral

250

indicates read insertion data, and numeral

251

indicates read display data. Other components identical with those of the reduction process section

231

previously described with reference to

FIG. 24

are denoted by the same reference numerals in FIG.

25

.

In

FIG. 25

, a preceding dot data latch

237

operates like that of the reduction process section

231

. The lateral operation section

240

performs an operation according to Expression

7

in response to the lateral display position signal

82

and outputs the result as the laterally enlarged data

247

. A line memory

242

and a longitudinal operation section

244

operate like those of the reduction process section

231

. The gray scale data frame memory

248

stores longitudinal gray scale data

245

for one frame and the display data frame memory

249

stores laterally enlarged data

247

for one frame. When display data of the next frame is input, the read insertion data

250

is read and inserted into any position between the read display data

251

in response to the longitudinal display position signal

83

for performing enlargement processes.

Next, the operation related to the reduction process according to the invention will be discussed in detail.

In

FIG. 1

, the data conversion section

4

converts the display data

2

and the timing signal

3

into the liquid display data and the liquid crystal display timing signal

6

matched with the liquid crystal panel

7

for output. In

FIG. 22

, the display position determination section

81

determines the position at which display data is to be displayed from the timing signal

3

and generates the lateral display position signal

82

and the longitudinal display position signal

83

. The lateral display position can be determined by counting liquid crystal display clock pulses (dot clock pulses) of the timing signal

3

and the longitudinal display position can be determined by counting liquid crystal horizontal clock pulses (line clock pulses) of the timing signal

3

. The display mode determination section

228

determines the display mode from the timing signal

3

and the display mode signal

229

matched with the resolution of the liquid crystal panel

7

for display. To determine the display mode, the number of lateral (horizontal) dots can be determined by counting the number of liquid crystal display clocks in one period of the liquid crystal horizontal clock of the timing signal

3

and the number of longitudinal (vertical) lines can be determined by counting the number of liquid crystal horizontal synchronizing signal periods in one period of liquid crystal vertical synchronizing signal. The display mode signal

229

can also be fed from an external system without providing the display mode determination section

228

.

The R, G, and B for the display data

2

are input to the R, G, and B data converters

222

,

223

, and

224

respectively, which then convert the data into the liquid crystal display data

5

matched with the display mode represented by the display mode signal

229

. The liquid crystal display timing signal generator

230

generates the liquid crystal display timing signal

6

matched with the display mode represented by the display mode signal

229

from the timing signal

3

.

The operation of the R data converter

222

for display data conversion will be discussed in detail with reference to FIG.

23

. Each of the G and B data converters

223

and

224

performs similar operations to that of the R data converter

222

.

In

FIG. 23

, when the display mode signal

229

represents the display mode

1

, the reduction process section

231

operates and generates the reduced display data

233

in response to the lateral display position signal

82

and the longitudinal display position signal

83

. When the display mode signal

229

represents the display mode

2

, the enlargement process section

232

operates and generates the enlarged display data

234

in response to the lateral display position signal

82

and the longitudinal display position signal

83

. The resolution switch means

235

is responsive to the display mode signal

229

for selecting and outputting the reduced display data

233

in the display mode

1

or the enlarged display data

234

in the display mode

2

. As described above, additional reduction and enlargement process sections can be provided to make up a data conversion section which supports every resolution.

The operation of the reduction process section

231

will be discussed in detail with reference to

FIGS. 24

,

27

, and

28

. In

FIG. 24

, the preceding dot data latch

237

, which latches R display data

219

according to a dot clock, outputs the preceding dot display data

239

which is the data one dot before the R data

219

. The pre-preceding dot data latch

236

, which latches the preceding dot data

239

according to a dot clock, outputs the pre-preceding dot data

238

which is the data two dots before the R data

219

. The lateral operation section

240

comprises an adder, multiplier, and divider. When the R display data

219

indicated by the lateral display position signal

82

is at the position X (0, 0)-X (0, 10), X (0, 13)-X (0, 23), or X (0, 26)-X (0, 34) shown in Expression 4, the lateral operation section

240

performs an operation on the R display data

219

and the preceding dot data

239

; when the R display data

219

is at the position X (0, 12) or X (0, 25), the lateral operation section

240

performs an operation on the R display data

219

, the preceding dot data

239

, and the pre-preceding dot data

238

; when the R display data

219

is at the position X (0, 11) or X (0, 24), the lateral operation section

240

does not output any data, thereby executing the operation shown in Expression 4. Lateral reduction can be accomplished by repeating similar calculations in 35-dot units. When the position of the R display data

219

indicated by the longitudinal display position signal

83

is the line next to the extraction line

210

shown in

FIG. 18

, the longitudinal operation section

244

performs an operation on the laterally reduced data

241

and the preceding line data

243

; otherwise, the longitudinal operation section

244

does not operate. When the position of the R display data

219

indicated by the longitudinal display position signal

83

is the extraction line

210

shown in

FIG. 18

, the output data selector

246

does not output display data; when the position is the line next to the extraction line

210

shown in

FIG. 18

, the output data selector

246

outputs the longitudinal reduced data

245

; otherwise, it outputs the laterally reduced data

241

.

FIG. 27

is an input/output timing chart for the lateral reduction process for the reduction process section

231

.

In the figure, numeral

2102

indicates the input timing for the R display data

219

, numeral

2103

indicates the output timing of preceding dot data

239

, numeral

2104

indicates the output timing for the pre-preceding dot data

238

, numeral

2105

indicates the output timing for the synchronous clock contained in the liquid crystal display timing signal

6

, numeral

2106

indicates the output timing of laterally reduced data

241

, and numeral

2107

indicates hatched data on which a lateral operation is to be performed. Each number following X represents the lateral display position (dot position) 0 to 34. Each number to which “′” is suffixed, shown in the output timing

2104

of the laterally reduced data

241

represents the display position after lateral reduction. For example, the first dot X0′ of the laterally reduced data

241

is the result of performing an operation on X0 and X1 shown as hatched data

2107

, and X10′ is the result of performing an operation on X10, X11, and X12. The operation is performed according to Expression 4 in response to the lateral display position signal

82

. The clock at the positions of X1, X13, and X25 of R display data is stopped and laterally reduced data

241

is output in synchronization with it, thereby deleting 3-dot data.

FIG. 28

is an input/output timing chart for the longitudinal reduction process for the reduction process section

231

.

In the figure, numeral

2108

indicates the line output timing for the laterally reduced data, numeral

2109

indicates the output timing of the preceding line signal

243

output by the line memory

242

, numeral

2110

indicates the output timing of longitudinal gray scale data

245

generated by performing an operation on the output of the line memory and the laterally reduced data, and numeral

2112

indicates the output timing of the reduced display data

233

output from the output data selector

246

. L

0

and L

1

denote data for the first line and data for the second line respectively; L

0

and L

1

are averaged to generate the longitudinal reduced data. This also applies to the second line, third line, and later. Numeral

2111

indicates a longitudinal position signal, which becomes a selection signal for the output data selector

246

to allow the longitudinal reduced data

245

to be output on the line next to the extraction line

210

shown in FIG.

18

. Numeral

2112

indicates the output timing for the reduced display data

233

, numeral

2113

indicates the output timing for a horizontal synchronizing signal contained in the liquid crystal display timing signal

6

, and numeral

2114

indicates the timing of display data actually displayed. Although the output timing

2112

for the output data selector

246

follows the longitudinal position signal timing

2111

, L

1

is not displayed as shown in

2114

because the actual horizontal synchronizing signal is as shown in

2113

.

The enlargement process according to the invention will be discussed in detail with reference to

FIGS. 25

,

12

, and

29

.

In

FIG. 25

, the preceding dot data latch

237

operates like that for the reduction process section

53

. When R display data

219

indicated by the lateral display position signal

82

is data at the dot position X (0, 0) shown in Expression 6, the lateral operation section

240

performs an operation only on the R display data

219

; when the R display data

219

is data at the dot position X (0, 1), X (0, 3), or X (0, 4), the lateral operation section

240

outputs 2-dot data for the operation result on the R display data

219

and the preceding dot data

239

and the operation result on only the R display data

219

while 1-dot R display data

219

is input; when the R display data

219

is data at the dot position X (0, 2), the lateral operation section

240

performs an operation on the R display data

219

and the preceding dot data

239

.

In

FIG. 25

, the line memory

242

and the longitudinal operation section

244

operate like those of the reduction process section

231

. Longitudinal gray scale data

245

for one screen (frame) is stored in the gray scale data frame memory

248

and laterally enlarged data

247

for one screen (frame) is stored in the display data frame memory

249

. When display data for the next screen (frame) is input, the read insertion data

250

is read and inserted into any position between the read display data

251

in response to the longitudinal display position signal for inserting a horizontal line. When a number of insertion lines are equally spaced, for example, when a gray scale data line is inserted every n lines, (n+1) line memories are provided for storing inserted gray scale data and line data. When the next data is input, the (n+1)-line data containing the gray scale line data is read out while n-line data is stored, whereby a horizontal line can be inserted without providing the frame memories.

FIG. 26

is an input/output timing chart for the lateral enlargement process of the enlargement process section

232

.

In the figure, numeral

2115

indicates the input timing of R display data

219

, numeral

2116

indicates the output timing of preceding dot data

239

, and numeral

2117

indicates the output timing of a synchronous clock contained in the liquid crystal display timing signal

6

, and numeral

2118

indicates the output timing of lateral enlarged data

247

. Each digit following X represents the lateral display position (dot position) 0 to 4. X0′ to X7′ of the laterally enlarged data

247

are the operation results according to Expression 7; while 5-dot data is input, 8-dot data is output according to the synchronous clock timing

2117

.

FIG. 29

is an. input/output timing chart for the longitudinal enlargement process of the enlargement process section

232

.

In the figure, numeral

2119

indicates the output timing of laterally enlarged data

247

for each line, numeral

2120

indicates the output timing of the preceding line data

243

for each line, output from the line memory

242

, and numeral

2121

indicates the output timing of longitudinal gray scale data

245

for each line, showing that the longitudinal gray scale data

245

is the result of dividing by two the sum of the laterally enlarged data

247

and the preceding line data

243

which is the data one line before the lateral enlarged data

247

. Numeral

2122

indicates the input timing of the longitudinal display position signal

83

, numeral

2123

indicates a horizontal synchronizing signal contained in the liquid crystal display timing signal

6

, and numeral

2124

indicates the timing for each line displayed on the liquid crystal panel

7

. The longitudinal display position signal input timing

2122

is set to “1” on the line next to the extraction line

214

shown in FIG.

20

. At this time, the period of the synchronous clock is doubled and while 1-line data is input, 2-line data is output. For the first one of these two lines, the longitudinal gray scale data is selectively output from the gray scale data frame memory

248

and for the second line, the laterally enlarged data is selectively output from the display data frame memory

249

by the output selector

246

.

Next, a system which simplifies the operation section will be discussed as another example of the data conversion section

4

according to another embodiment of the invention.

To simplify the operation expressions given in the first example of the data conversion section

4

, the dividers may be omitted by assigning 8 or 16 to each divisor. Therefore, the operation section can be simplified by reducing 16 pixels to 15 pixels according to Expression 9 or eight pixels to seven pixels according to Expression 10:

X(0,0)′=(X(0,0)×15+X(0,1)×1)/16

X(0,1)′=(X(0,1)×14+X(0,2)×2)/16

X(0,2)′=(X(0,2)×13+X(0,3)×3)/16

X(0,3)′=(X(0,3)×12+X(0,4)×4)/16

X(0,4)′=(X(0,4)×1+X(0,5)×5)/16

X(0,5)′=(X(0,5)×10+X(0,6)×6)/16

X(0,6)′=(X(0,6)×9+X(0,7)×7)/16

X(0,7)′=(X(0,7)×8+X(0,8)×8)/16

X(0,8)′=(X(0,8)×7+X(0,9)×9)/16

X(0,9)′=(X(0,9)×6+X(0,10)×10)/16

X(0,10)′=(X(0,10)×5+X(0,11)×11)/16

X(0,11)′=(X(0,11)×4+X(0,12)×12)/16

X(0,12)′=(X(0,12)×3+X(0,13)×13)/16

X(0,13)′=(X(0,13)×2+X(0,14)×14)/16

X(0,14)′=(X(0,14)×1+X(0,15)×15)/16 Expression 9

X(0,0)′=(X(0,0)×7+X(0,1)×1)/8

X(0,1)′=(X(0,1)×6+X(0,2)×2)/8

X(0,2)′=(X(0,2)×5+X(0,3)×3)/8

X(0,3)′=(X(0,3)×4+X(0,5)×5)/8

X(0,4)′=(X(0,4)×3+X(0,1)×1)/8

X(0,5)′=(X(0,5)×2+X(0,6)×6)/8

X(0,6)′=(X(0,6)×1+X(0,7)×7)/8 Expression 10

These expressions can be used to reduce 1120 lateral pixels to 1024 pixels by reducing from 16 pixels to 15 pixels for 704 pixels of the 1120 pixels and from eight pixels to seven pixels for 416 pixels. Thus, reduction process compatible with every resolution can be carried out by combining reduction methods by which dividers can be omitted.

As still another example of the data conversion section

4

, a system which executes reduction process in dot units will be discussed with reference to FIG.

30

. Here, assume that a dot refers to a display element of each of R, G, and B making up one pixel of a color liquid crystal panel and that one pixel consists of three dots. The pixels of R, G, and B are arranged in order on a horizontal line on the liquid crystal panel.

FIG. 30

shows a concept of reduction process executed in dot units. Here, assume that 12 pixels are to be reduced to 11 pixels, namely, 36 dots to 33 dots.

In

FIG. 30

, numerals

254

,

255

, and

256

indicate first, second, and third extraction pixels respectively. Gray scale (average) of the display data in the B dot of the first extraction pixel

254

and the display data in the B dot of its preceding pixel is calculated and the result is displayed in the B dot of the pixel preceding the first extraction pixel

254

. Gray scale (average) of the display data in the G dot of the second extraction pixel

255

and the display data in the G dot of its preceding pixel is calculated and the result is displayed in the G dot of the pixel preceding the second extraction pixel

255

. Gray scale (average) of the display data in the R dot of the third extraction pixel

256

and the display data in the R dot of its preceding pixel is calculated and the result is displayed in the R dot of the pixel preceding the third extraction pixel

256

. Since the system performs reduction process in units of dots smaller than pixels, characters and graphics are less deformed. Alternatively, six pixels can also be reduced to five pixels, namely, 18 dots to 15 dots.

The data conversion section

4

which performs the processing may be software using the CPU

101

, may be made of hardware, may exist in the PC

1

, or may be contained in the liquid crystal panel

7

.

An example of a system to which the invention is applied will be discussed with reference to

FIGS. 31 and 32

.

FIG. 31

is a conceptual illustration of the system to which the invention is applied.

In

FIG. 31

, numeral

257

indicates a workstation or personal computer which contains a central processing unit and a numeral

258

indicates a liquid crystal display unit. The workstation or personal computer

257

outputs display data having different resolutions and the liquid crystal display unit

258

has means for converting the input display data in accordance with the resolution of its own liquid crystal panel. Here, assume that the workstation or personal computer

257

outputs display data having three resolutions of 1120×780 dots, 1024×768 dots, and 640×480 dots and that the liquid crystal display unit

257

has a liquid crystal panel of a resolution of 1024×768 dots.

FIG. 32

shows the configuration of the liquid crystal display unit

258

, wherein numeral

259

indicates PC display data, numeral

260

indicates a PC vertical synchronizing signal, numeral

261

indicates a PC horizontal synchronizing signal, and numeral

262

indicates an input circuit. The input circuit

262

converts an input signal into a TTL level. For example, if the input signal is at ECL level, the input circuit

262

converts the ECL level into TTL level; if the input signal is an analog signal, the input circuit

262

converts the analog signal into digital form; if the input signal is at TTL level, the input circuit

262

serves as a buffer. Numeral

263

indicates a clock generator which generates a liquid crystal display clock, one of liquid crystal timing signals synchronized with the PC display data

259

from the PC horizontal synchronizing signal

261

. Numeral

4

indicates a data conversion section which operates as the data conversion section

4

described above, and here determines the resolution of the PC display data

259

from the liquid crystal timing signal

3

and executes reduction process when the resolution is 1120×780 dots, outputs the PC display data as it is when the resolution is 1024×768 dots, or executes enlargement process when 640×480 dots.

We have discussed the enlargement/reduction techniques as execution of the enlargement or reduction process so that the display data output from the PC

1

is made the same as the liquid crystal panel in resolution directly, but a technique of step-by-step execution of enlargement or reduction process may be used as described above.

Thus, display data can be displayed on a panel having a different resolution by enlarging or reducing the display data using algorithms of generating 32-pixel data from 35-pixel data, 15-pixel data from 16-pixel data, 7-pixel data from 8-pixel data, 8-pixel data from 5-pixel data, etc.

As described above, operations are performed on gradation information on a plurality of pixels or dots and display data is enlarged or reduced according to the result, whereby even display data output by the personal computer system assuming an output device having resolution different from that of the liquid crystal display can be displayed without erasing thin lines or deforming characters and without impairing display information of the resolution before enlargement or reduction. That is, a liquid crystal display system which enables multi-scanning display can be provided.

Considering the current state in which a large number of software products are already distributed, the system can eliminate the need for correcting a large number of software products so as to output signals matched with the resolution of a liquid crystal display from a computer to enable multi-scanning; an inexpensive system can be provided.

Number	Date	Country	Kind
5-245205	Sep 1993	JP
5-251363	Oct 1993	JP

Number	Name	Date
2921124	Graham	Jan 1960
4528693	Pearson et al.	Jul 1985
4571584	Suzuki	Feb 1986
4746981	Nadan et al.	May 1988
4777602	Wesner	Oct 1988
4866519	Lucas et al.	Sep 1989
4998100	Ishii	Mar 1991
5059963	Fukuoka	Oct 1991
5107255	Shiraishi	Apr 1992
5184218	Gerdes	Feb 1993
5185817	Degi et al.	Feb 1993
5194937	Lee et al.	Mar 1993
5267045	Stroomer	Nov 1993
5272468	Read	Dec 1993
5272471	Asada et al.	Dec 1993
5285192	Johary et al.	Feb 1994
5379057	Clough et al.	Jan 1995
5381182	Miller et al.	Jan 1995
5475808	Kobayashi	Dec 1995
5515068	Uragami et al.	May 1996
5534883	Koh	Jul 1996
5592194	Nishikawa	Jan 1997
5612714	Souviron	Mar 1997

	Number	Date	Country
Parent	08/315714	Sep 1994	US
Child	09/614910		US

Liquid crystal display system capable of reducing and enlarging resolution of input display data

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Disclaimer

Abstract

Description

Claims

Priority Claims (2)

CROSS-REFERENCE TO RELATED APPLICATION

US Referenced Citations (23)

Foreign Referenced Citations (1)

Continuations (1)