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

• US 6,118,429 A
• Filed: 09/30/1994
• Issued: 09/12/2000
• Est. Priority Date: 09/30/1993
• Status: Expired due to Term

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tanaka, Toshio, Wakisaka, Shinji, Kasai, Naruhiko, Suzuki, Tetsuya, Uchida, Mitsutoshi, Mano, Hiroyuki, Nishitani, Shigeyuki, Sato, Hiroko, Hasegawa, Kazuko, Hamada, Tatsuzo
• Primary Examiner(s): Lao, Lun-Yi
• Application Number:
  US08/315,714
• Time in Patent Office: 2,174 Days
• Field of Search: 348/392, 348/424, 348/448, 348/458, 345/132, 345/202, 345/129, 345/130, 345/127, 345/138, 345/136, 345/1-3, 345/87, 345/88, 345/99, 345/98
• US Class Current: 345/428
• CPC Class Codes: G09G 2340/0414 Vertical resolution change
• CPC Class Codes: G09G 2340/0421 Horizontal resolution change
• CPC Class Codes: G09G 2360/02 Graphics controller able to handle multiple formats, e.g. input or output formats
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A liquid crystal display system which can accept display data having a resolution different from that of a screen for the liquid crystal display and display the display data. For example, a CPU outputs display data of 1120×780 dots and a liquid crystal panel has a 1024×768-dot resolution which is smaller than the display data resolution. The display screen of the liquid crystal panel comprises a linear arrangement of pixels. A data conversion section generates display data for a new horizontal or vertical line based on display data for two horizontal or vertical lines contiguous to each other and repeats replacement of display data of the two lines with the display data of the one line for reducing the number of horizontal lines of one screen and the number of dots of one line so as to match the resolution of the display data output by the CPU with the liquid crystal display. In contrast, if the resolution of the display data is smaller than the screen resolution of the liquid crystal panel, the data conversion section inserts the display data of the new one horizontal or vertical line between the two contiguous lines for enlarging the resolution of the display data.

Claims

1. A method of converting first display data for a liquid crystal display 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, said method comprising the steps of:

a) generating N dots based on a set of M contiguous dots on a horizontal line of the first display data, where M is an integer of three or greater and N is an integer of two or more being less than M;

b) replacing the set of M contiguous dots on the horizontal line of the first display data with the N dots;

c) repeating steps a) to b) for different sets of M contiguous dots on the horizontal line of the first display data in sequence at least in a part of the horizontal line of the first display data; and

d) repeating step c) for different horizontal lines of the first display data in sequence;

wherein the step a) generates the N dots based on the set of M contiguous dots on the horizontal line of the first display data such that the set of M contiguous dots is virtually divided into N equal partitions, and as to each of the N equal partitions a new dot is generated by averaging one or more dots contained in the partition concerned; and

wherein when a dot of the M contiguous dots is located on a border between two partitions, the dot is assigned to each of the two partitions to be added with a weight according to a percentage of an area of the dot in each of the two partitions.

2. The method as claimed in claim 1, wherein M is 35 and N is 32.

3. The method as claimed in claim 1, wherein M is 16 and N is 15.

4. The method as claimed in claim 1, wherein M is eight and N is seven.

5. The method as claimed in claim 1 wherein each horizontal line of the first display data is divided into at least first and second horizontal line portions and a ratio of M and N is set different between in the first horizontal line portion and in the second horizontal line portion.

6. The method as claimed in claim 5, wherein M and N are set equal to eight and seven for the first horizontal line portion, respectively, and M and N are set equal to sixteen and fifteen for the second horizontal line portion, respectively.

7. The method as claimed in claim 1, further comprising the steps of:

e) generating data for n horizontal lines based on specific m 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;

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

g) replacing k (n<

k≦

m) lines of the m horizontal lines with the n horizontal lines; and

h) adding the n horizontal lines to the m horizontal lines;

whereby the first data having the first vertical resolution is converted into the display data having the second vertical resolution which differs from the first vertical resolution.

8. The method as claimed in claim 7, wherein m is two, n is one, and k is two.

9. The method as claimed in claim 7, wherein m is three, n is one, and k is two.

10. The method as claimed in claim 1, wherein the first display data has a first vertical resolution and the second display data has a second vertical resolution different from the first vertical resolution;

and

wherein the method further comprises the steps of;

e) generating Q dots based on a set of P contiguous dots on a vertical line of the first display data, where P is an integer of three or greater and Q is an integer of two or more being less than P;

f) replacing the set of P contiguous dots on the vertical line with the Q dots;

g repeating steps e) to f) for different sets of P contiguous dots on the vertical line of the first display data in sequence at least in a part of the vertical line of the first display data; and

h) repeating step g for different vertical lines of the first display data in sequence;

wherein the step e) generates the Q dots based on the set of P contiguous dots on the vertical line of the first display data such that the set of P contiguous dots is virtually divided into Q equal partitions, and as to each of the Q equal partitions, a new dot is generated by averaging one or more dots contained in the partition concerned; and

wherein when a dot of the P contiguous dots is located on a border between two partitions, the dot is assigned to each of the two partitions to be added with a weight according to a percentage of an area of the dot in each of the two partitions;

whereby the first display data having the first vertical resolution is converted into the display data having the second vertical resolution different from the first vertical resolution.

11. The method as claimed in claim 10, wherein the sets of P contiguous dots are selected out of a screen area which contains substantially only background color dots of the first display data.

12. The method as claimed in claim 1, wherein the sets of M contiguous dots are selected out of a screen area which contains substantially only background color dots of the first display data.

13. The method as claimed in claim 1, wherein each horizontal line of the first display data is divided into first, second, and third horizontal line portions, and step d) is applied only to the second horizontal line portion without being applied to the first and third horizontal line portions.

14. A method of converting first display data for a liquid crystal display having a first horizontal resolution received from an external system into second display data for a liquid crystal display having a second horizontal resolution larger than the first horizontal resolution, said method comprising the steps of:

a) generating N dots based on a set of m contiguous dots on a horizontal line of the first display data, where M is an integer of two or greater and N is an integer of three or more being greater than M;

b) replacing the set of M contiguous dots on the horizontal line of the first display data with the N dots;

c) repeating steps a) to b) for different sets M contiguous dots on the horizontal line of the first display data in sequence at least in a part of the horizontal line of the first display data; and

d) repeating step c) for different horizontal lines of the first display data in sequence;

wherein the step a) generates the N dots based on the set of M contiguous dots on the horizontal line of the first display data such that the set of M contiguous dots is virtually divided into N equal partitions, and as to each of the N equal partitions, a new dot is generated by averaging one or more dots contained in the partition concerned; and

wherein when a dot of the M contiguous dots is located on a border between two partitions, the dot is assigned to each of the two partitions to be added with a weight according to a percentage of an area of the dot in each of the two partitions.

15. The method as claimed in claim 14 wherein M is five and N is eight.

16. The method as claimed in claim 14, further comprising the steps of:

e) generating data for n horizontal lines based on specific m 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;

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

g) replacing k (n<

k≦

m) lines of the m horizontal lines with the n horizontal lines; and

h) adding the n horizontal lines to the m horizontal lines;

whereby the first data having the first vertical resolution is converted into the display data having the second vertical resolution which differs from the first vertical resolution.

17. The method as claimed in claim 16, wherein m is two, n is one, and k is two.

18. The method as claimed in claim 16, wherein m is three, n is one, and k is two.

19. A method of converting first color display data in a raster scan format having a first horizontal resolution received from an external system into second color display data for a liquid crystal display having a second horizontal resolution smaller than the first horizontal resolution, the liquid crystal display including pixels each consisting of three primary color dots of R (red), G (green), and B (blue), said method comprising the steps of:

a) averaging data values of both a different primary color dot of each of three pixels which are at least every other pixel of M contiguous pixels on each horizontal line of the first display data and the same color dot of a pixel immediately preceding the pixels, where M is an integer of six or greater;

b) sharing the average values as data values of the different primary color dots between the three pixels which are at least every other pixel of M contiguous pixels and their respective immediately preceding pixels;

c) for data for M-1 pixels thus obtained from the first display data, changing an arrangement of the primary color dots of the data so that it matches an arrangement of primary color dots of the liquid crystal display;

d) assigning data for each primary color dot of the M-1 pixels whose primary color dot arrangement is changed to each primary color dot of M-1 contiguous pixels of the liquid crystal display; and

e) repeating steps a) to d) for different sets of M pixels on each horizontal line in sequence.

20. The method as claimed in claim 19, wherein M is 12.

21. A method of converting first display data for a liquid crystal display having a first horizontal resolution received from an external system into second display data for a liquid crystal display having a second horizontal resolution larger than the first horizontal resolution, the method comprising the steps of:

a) generating N dots based on a set of M contiguous dots on a horizontal line of the first display data, where M is an integer of two or greater, N is an integer of three or more being greater than M, and (N-M)/(M-1) is not an integer;

b) replacing the set of M contiguous dots on the horizontal line of the first display data with the N dots;

c) repeating steps a) to b) for different sets of contiguous dots on the horizontal line of the first display data in sequence at least in a part of the horizontal line of the first display data; and

d) repeating step c) for different horizontal lines of the first display data in sequence;

wherein the step a) generates the N dots based on the set of M contiguous dots on the horizontal line of the first display data such that the set of M contiguous dots is virtually divided into N equal partitions, and as to each of the N equal partitions, a new dot is generated by averaging one or more dots contained in the partition concerned; and

wherein when a dot of the M contiguous dots is located on a border between two partitions, the dot is assigned to each of the two partitions to be added with a weight according to a percentage of an area of the dot in each of the two partitions.

22. The method as claimed in claim 21, wherein M is five and N is eight.

23. The method as claimed in claim 21, wherein the first display data has a first vertical resolution and the second display data has a second vertical resolution different from the first vertical resolution;

and

wherein the method further comprises the steps of;

e) generating Q dots based on a set of P contiguous dots on a vertical line of the first display data into Q equal partitions, where P is an integer of two or greater and Q is an integer of three or more being greater than P;

f) replacing the set of P contiguous dots on the vertical line of the first display data with the Q dots;

g) repeating steps e) to f) for different sets of P contiguous dots on the vertical line of the first display data in sequence at least in a part of the vertical line of the first display data; and

h) repeating step g) for different vertical lines of the first display data in sequence;

wherein the step e) generates the Q dots based on the set of P contiguous dots on the vertical line of the first display data such that the set of P contiguous dots is virtually divided into Q equal partitions, and as to each of the Q equal partitions, a new dot is generated by averaging one or more dots contained in the partition concerned; and

wherein when a dot of the P contiguous dots is located on a border between two partitions, the dot is assigned to each of the two partitions to be added with a weight according to a percentage of an area of the dot in each of the two partitions;

whereby the first display data having the first vertical resolution is converted into the second display data having the second vertical resolution different from the first vertical resolution.

24. The method as claimed in claim 23, wherein P is four and Q is five.

25. The method as claimed in claim 23, wherein the sets of P contiguous dots are selected out of a screen area which contains substantially only background color dots of the first display data.

26. The method as claimed in claim 21, wherein M is four and N is five.

27. The method as claimed in claim 21, wherein the sets of M contiguous dots are selected out of a screen area which contain substantially only background color dots of the first display data.

28. A circuit for converting first display data in a raster scan format having a first resolution and a first timing signal received from an external system into second display data for a liquid crystal display having a second resolution different from the first resolution and a second timing signal, the circuit comprising:

a latch which outputs the first display data after a delay to produce delayed first display data;

a horizontal calculation unit which performs a calculation based on the first display data and the delayed first display data;

a selector which selectively outputs one of the first display data and a calculation result obtained by the horizontal calculation unit depending on a position of the liquid crystal display to which the first display data corresponds; and

a circuit which generates the second timing signal based on the first timing signal.

29. A circuit for converting first display data in a raster scan format having a first resolution and a first timing signal received from an external system into second display data for a liquid crystal display having a second resolution different from the first resolution and a second timing signal, the circuit comprising:

a line memory which outputs the first display data after a delay of one line period to produce delayed first display data;

a vertical calculation unit which performs a calculation based on the first display data and the delayed first display data;

a selector which selectively outputs one of the first display data and a calculation result obtained by the vertical calculation unit depending on a position of the liquid crystal display to which the first display data corresponds; and

a circuit which generates the second timing signal based on the first timing signal.