JPH09244572A - Method and device for displaying image, and data transmission method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably reduce undesired radiation and to reduce power consumption by transmitting one color data and a color data control signal having a first level when plural color data are provided with the same value and transmitting plural color data and the color data control signal having a second level different from the first level when they are provided with different values. SOLUTION: When the black/white data are transmitted from a main device 11 side to a display device 12 side, one among the plural color data are transmitted from the main device 11 side to the display device 12 side, and the remainder among the plural color data aren't transmitted from the main device 11 side to the display device 12 side. Further, when one among the plural color data are transmitted from the main device 11 side to the display device 12 side, the main device 11 performs at least one side between the operation making high impedance a signal line answering to the color data without being transmitted from the main device 11 side to the display device 12 side among the plural color data and the operation holding the potential of the signal line answering the color data to a fixed level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for displaying an image having a plurality of gradations based on a plurality of color data defining a plurality of color components, and a plurality of color data from a computer main body. A method of transmitting to a display device.

The present invention provides a plasma display device, an EL display device, a field effect display device (FE) in addition to a liquid crystal drive device for controlling the liquid crystal display of a computer or the like with digital display data.
It can also be applied to flat display devices such as D).

[0003]

2. Description of the Related Art Generally, a flat panel display device can be roughly divided into a main engine portion and a display portion, and the main engine portion side outputs a display data signal, a control signal and the like. On the display portion side, display is performed based on the output signal from the main engine portion side. As the display portion, for example, a liquid crystal driving device, a plasma display device,
An EL display device, a field effect display device (FED) or the like is used.

In recent years, portable notebook computers have become common, especially as computers have become smaller and lighter. The conventional technique will be described below by taking a computer equipped with a liquid crystal display device, which has been attracting attention as a display device replacing the conventional CRT, as an example.

FIG. 5 shows a block diagram of a conventional computer 50. The computer 50 is roughly divided into a computer main body 51 which is a main machine part and a liquid crystal display device 52 which is a display part. The computer main body 51 is generally connected to a central processing unit, a storage device, an auxiliary storage device (storage device such as a hard disk), and other peripheral devices.

From the computer main body 51 to the liquid crystal display device 5
2 includes display data (Data) 13, a clock signal (CK) 14, and a synchronization signal (Hsync, Vsyn, etc.) 1.
5 and 5 have been transmitted.

The liquid crystal display device 52 receives the display data 13, the clock signal 14, and the synchronization signal 15, and based on the synchronization signal 15 and the clock signal 14, the display data 13 is displayed.
Is sampled. The sampled data is supplied to the display unit 20 and displayed in multiple colors there.

When the liquid crystal display device 52 is color-compatible, the display data 13 includes a plurality of color data defining a plurality of color components. Typically, the display data 13 includes color data (R) defining a red component, color data (G) defining a green component, and color data (B) defining a blue component. An arbitrary color is synthesized by mixing the red color component defined by the color data (R), the green color component defined by the color data (G) and the blue color component defined by the color data (B) at a predetermined ratio. can do. Each of the color data (R), the color data (G), and the color data (B) can be represented by a plurality of bit values.

[0009]

When the liquid crystal display device 52 is color-compatible, the computer main body 51 causes the liquid crystal display device 52 to display color data (R) defining the red component and a color defining the green component. It is necessary to transmit the data (G) and the color data (B) defining the blue component. Therefore, signal lines corresponding to these color data are required. For example, in the case of displaying approximately 260,000 colors for one pixel with 6-bit color data of R, G, and B, a total of 18 signal lines of 6 bits × 3 are used as shown in FIG. Color data will be transmitted. In FIG. 6, R0 to R5
Indicates each bit forming the color data (R), and G0 to G0
G5 indicates each bit forming the color data (G), and B
0 to B5 indicate each bit forming the color data (B). A few years ago, a liquid crystal display device that displayed 4096 colors with 4 bits for each color was exhibited as a prototype at the Electronics Show.
Bits that display approximately 260,000 colors have come into mass production. Depending on the application, more multicolor display is desired. When performing multi-color display of about 16,770,000 colors with 8-bit color data for each of R, G, and B, the color data is transmitted using a total of 24 signal lines of 8 bits × 3, The number of six signal lines is increased as compared with the case of displaying about 260,000 colors with 6-bit color data for each of R, G, and B.

In order to make it easier to understand the relationship between the color data, the display basic color and the brightness gradation of each color, in the case of displaying 4096 colors with 4 bits for each color, the color data, the display basic color and the brightness gradation of each color are displayed. The relationship is shown in FIG. In FIG.
In particular, in the case of black and white gradation display, (a), (b),
Whichever of (c) is taken, the color data of each R, G, B bit is the same.

Further, the color data of each of the R, G and B bits shown above is increased (4 bits each → 6 bits each → 8 bits →
...) increases the circuit scale of the computer main body 51 (main machine side) and the liquid crystal display device 52 (display device side), resulting in an increase in power consumption. The computer main body 51 (main machine side) requires a drive circuit corresponding to each bit for outputting a signal corresponding to each bit forming the color data. Similarly, the liquid crystal display device 52 (display device side) also requires a circuit for processing color data and the like.

The most important point of the notebook computer is that it has excellent portability and can be used anytime, anywhere. As described above, when multicolor display is performed, the power consumption increases, so the battery drive time becomes shorter. This is a big problem because it is very difficult for a user of a notebook computer to use.

In a notebook type personal computer, a laptop type personal computer, a workstation, or the like in which the computer main body 51 and the liquid crystal display device 52 are separated from each other, in order to increase the number of colors that can be displayed, the computer main body 51 and the liquid crystal display. The number of signal lines for the display data 13 between the display devices 52 must be increased. As the number of signal lines increases, the electromagnetic interference called unnecessary radiation will inevitably increase accordingly.

FIG. 7 shows the timing of transmitting binary digital data using 18 signal lines of 6 bits × 3 as shown in FIG. This transmission is based on the VGA specification (dot configuration: 640 × RGB × 480).

In FIG. 7, the waveform indicated by Data indicates display data, and the red, blue, and green color data are collectively expressed in this way. Further, in FIG. 7, Dl is the first horizontal display data, and D640 is the horizontal 64.
The 0th display data, DH1 indicates the first vertical display data, and DH480 indicates the period during which the vertical 480th display data is output. In FIG. 7, the data within the valid data period is sampled based on the clock signal (CK) so that the display unit 20 can display multi-color data. There are some methods for dividing the non-valid data period and the valid data period, but the description thereof is omitted because they are not directly related to the present invention.

FIG. 9 shows the relationship between display data and screen display. As shown in FIG. 9, 640 pixels (RG
(1 pixel for one set of B), 480 pixels in the vertical direction for a total of 39
7,200 (640 × 480) pixels are arranged in a matrix.

In the case of the VGA type display device, which has been the most general type of digital display data transmission, the transfer time of one data is about 40 nsec, and the transmission of digital display data is about 2 n synchronized with the data.
A transfer clock of 5 MHz is sent to the liquid crystal display device in parallel with the data.

By the way, recently M from Microsoft
With the rapid spread of S-Windows, higher definition of the display body has been advanced, and in the display device using the cathode ray tube, the display from XGA to SXGA is already becoming popular. There is a strong demand for high definition even in a flat-panel display device, and for example in a liquid crystal display device, a conventional VGA (dot structure:
640 × RGB × 480 to SVGA (800 × RG)
BGA x 600), and even higher definition XGA (1024
X RGB x 768), SXGA (1280 x RGB x 1)
024).

The liquid crystal display device receives display data serially and, when data for one line is complete, supplies the display data in parallel to the liquid crystal panel. Since the display data for a line tends to increase with the increase in size and definition of the liquid crystal display screen, the frequency of the clock pulse for fetching the display data within a predetermined fixed time is also 3 MHz to 8 MHz. Such high frequencies are needed.

For example, in the case of XGA, about 60 MHz, S
In the case of XGA, a high speed clock of about 100 MHz is required.

As described above, the definition of the display device is improved (VGA →
Due to SVGA → XGA → SXGA), when binary digital data is transmitted at high speed, electromagnetic interference called unnecessary radiation occurs. In addition, as for the high definition of the display device, the computer main body 51 (main machine side) and the liquid crystal display device 52 (display side)
This increases the circuit scale on the side and causes an increase in power consumption.

The liquid crystal display device used as a display device is one of the information processing devices, and the Voluntary Control Council for Interference by Information Technology Devices (VCCI), the Federal Communications Commission Regulations (F
CC) and other products subject to unnecessary radiation regulations. Naturally, there are regulations for the electromagnetic interference,
In order to suppress unnecessary radiation within the officially determined standards, engineers are forced to take great effort and take countermeasures.

In the prior art, in order to solve the problem of unnecessary radiation, Japanese Patent Laid-Open Nos. 6-216480 and 6-37.
478 and Japanese Patent Laid-Open No. 6-95618 are disclosed.

(A) Japanese Unexamined Patent Publication No. 6-216480 discloses that "a circuit board is provided with a shield, and the shield is mounted on the integrated circuit in order to suppress unnecessary radiation noise of the integrated circuit.
Alternatively, it is connected to the GND of the system frame. It is disclosed.

(B) Japanese Patent Application Laid-Open No. 6-37478 discloses, "A metal foil is attached to an input interface signal system wiring or a power supply system wiring in a mounting board on which an IC for driving a liquid crystal display panel is mounted, and a shield is provided. It will be applied. "

(C) Japanese Patent Laid-Open No. 6-95618 discloses that "the number of signal lines of input data is reduced by dividing and transmitting digital display data."

However, the above method alone is not sufficient. The present invention has been made to solve a difficult situation for suppressing unnecessary radiation, and an object thereof is to provide a transmission method and a power consumption reduction method in which unnecessary radiation is significantly reduced. .

[0028]

The method of the present invention is a method of transmitting a plurality of color data defining a plurality of color components respectively from a main machine side to a display device, and the plurality of color data having the same value. If one of the plurality of color data is
A first transmitting step of transmitting one color data and a color data control signal having a first level from the main unit side to the display device; and when the plurality of color data have different values,
A second transmission step of transmitting the plurality of color data and a color data control signal having a second level different from the first level from the main unit side to the display device. Is achieved.

In the first transmission step, a signal line corresponding to color data other than the one color data transmitted in the first transmission step is set to high impedance, and in the first transmission step, the transmission is performed. At least one of the steps of maintaining the potential of the signal line corresponding to the color data other than the one color data to be maintained at a constant level.

The fixed level may be either a high level or a ground level.

Another method of the present invention is a method of displaying an image having a plurality of gradations based on a plurality of color data defining a plurality of color components in a display device connected to the main machine side. Receiving a color data control signal and determining whether or not the level of the color data control signal is a predetermined level; and if the level of the color data control signal is the predetermined level, Receiving one of the color data, and creating the remaining color data of the plurality of color data based on the received one color data; the received one color data; Displaying an image having a plurality of gradations based on the created color data, thereby achieving the above object.

The apparatus of the present invention is an apparatus which is connected to the main machine side and which displays an image having a plurality of gradations based on a plurality of color data defining a plurality of color components respectively, and which outputs a color data control signal. Means for receiving and determining whether or not the level of the color data control signal is at a predetermined level, and, if the level of the color data control signal is at the predetermined level, of the plurality of color data Means for receiving one color data and creating remaining color data of the plurality of color data based on the received one color data, the received one color data and the created color data And a means for displaying an image having a plurality of gradations on the basis of the above.

The plurality of color data typically includes color data representing red (R), color data representing green (G), and color data representing blue (B).

When data is transmitted by such a method,
The effect of reducing EMI is particularly great during word processing work on a computer or the like in which black and white (monotone) gradation display occupies most of the screen.

The present invention has been made in order to solve the difficult situation for suppressing unnecessary radiation, and can provide a transmission method with significantly less unnecessary radiation, which is disclosed in Japanese Patent Laid-Open No. 6-95618 shown in the prior art. JP-A-6-216480 and JP-A-6-37478 do not describe the contents related to the present invention, and are completely different.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The point of the present invention is to pay attention to the black and white gradation display in "input signal and basic color and luminance gradation of each color" shown in FIG. 8 and the screen used by a general notebook computer. . According to the present invention, when transmitting black and white data from the main machine side to the display device side, one of a plurality of color data (for example, color data (R), color data (G)) is transmitted.
And only the color data (R) of the color data (B) is transmitted from the main machine side to the display device side, and the remaining ones (for example, the color data (G) and the color data (B)) of the plurality of color data are transmitted. ) Is not transmitted from the main unit to the display device side. When one of the plurality of color data is transmitted from the main machine side to the display device side, the main machine side outputs a signal corresponding to the color data that is not transmitted from the main machine side to the display device side among the plurality of color data. At least one of an operation of making the line high impedance and an operation of keeping the potential of the signal line corresponding to the color data at a constant level is performed. The certain level may be a high level or a low level (ground level). This eliminates the difficult situation of suppressing unwanted radiation. It is an object of the present invention to provide a transmission method with significantly less unnecessary radiation and a power consumption reduction method.

(Embodiment 1) FIG. 1 is a block diagram of a computer 10 according to the present invention. Computer 10
It has a computer main body 11 on the main machine side and a liquid crystal display device 12 on the display device side. The computer main body 11 is
Generally, it has a configuration in which a central processing unit, a storage device, an auxiliary storage device (a storage device such as a hard disk), and other peripheral devices are connected. The present invention relates to a display control circuit section of a computer main body 11 (main machine side) and a liquid crystal display device 1.
2 (display device side), the description of the central processing unit, the storage device, etc. will be omitted.

From the computer main body 11 to the liquid crystal display device 1
2 includes display data (Data) 13, a clock signal (CK) 14, and a synchronization signal (Hsync, Vsyn, etc.) 1.
5 and the color data control signal (BW) 16 are transmitted.
The color data control signal (BW) 16 is sent to the computer main body 1
It is a signal indicating whether or not the data transmitted from 1 (main machine side) to the liquid crystal display device 12 (display device side) is monochrome (monotone) gradation display data.

When the liquid crystal display device 12 is color-compatible, the display data 13 includes a plurality of color data defining a plurality of color components. Typically, the display data 13 includes color data (R) defining a red color component, color data (G) defining a green color component, and color data (B) defining a blue color component. The plurality of color data included in is not limited to the color data (R), the color data (G), and the color data (B). As long as an arbitrary color can be synthesized, the display data 13 may include color data defining an arbitrary color component.

1. Movement of computer main body 11 (main machine side)
When transmitting the gradation display data created (a) B & W (black and white) on the liquid crystal display device 12 (display device side): a clock signal 14, the synchronization signal 15, a plurality of which are included in the color data control signal 16 and the display data 13 Only one of the color data is transmitted to the display device side.

For example, the display control circuit section on the main machine side sets the color data control signal 16 to the "H" level.

Further, for example, the display control circuit section on the main machine side transmits only the color data (R) and does not transmit the other two color data (color data (G) and color data (B)). In this case, the display control circuit unit on the main machine side further performs at least one of the first to third operations described below. The first operation is an operation of high impedance a signal line corresponding to color data that is not transmitted from the main machine side to the display device side. The second operation is an operation of setting the potential of the signal line corresponding to the color data which is not transmitted from the main unit side to the display device side to the high level. The third operation is an operation of setting the potential of the signal line corresponding to the color data not transmitted from the main unit side to the display device side to the ground level.

As a result, unnecessary radiation can be greatly reduced and power consumption can be reduced.

(B) When transmitting gradation display data other than black and white (monotone) to the liquid crystal display device 12 (display device side): included in the clock signal 14, the synchronization signal 15, the color data control signal 16 and the display data 13. All the plurality of color data to be transmitted are transmitted to the display device side. For example, the display control circuit unit on the main machine side sets the color data control signal 16 to the “L” level. For example, the display control circuit unit on the main machine side transmits all the color data (R), the color data (G), and the color data (B).

2. Movement of the liquid crystal display device 12 (display device side)
The working liquid crystal display device 12 receives the color data control signal 16 from the main unit side.
And the gradation display data from the main machine side is black and white (monotone) according to the level of the color data control signal 16
It is determined whether or not it is the gradation display data. Inside the liquid crystal display device 12, the display data 13 is sampled based on the synchronization signal 15 and the clock signal 14. The sampled data is supplied to the display unit 20 and displayed in multiple colors there. The operation of the liquid crystal display device 12 differs depending on the level of the color data control signal 16 received by the liquid crystal display device 12. Therefore, the operation will be described separately for the following cases (a) and (b). For example, the case where the level of the color data control signal 16 is determined to be the “H” level corresponds to the case (a) below, and the color data control signal 16
The case where the level is determined to be the “L” level corresponds to the case (b) below.

(A) When black-and-white (monotone) gradation display data is received from the computer main body 11 (main machine side): The liquid crystal display device 12 uses the plurality of color data included in the display data 13 as gradation display data. Only one of the color data (for example, only color data (R)) is received.
The liquid crystal display device 12 also uses the received one color data as other color data. For example, when one received color data is color data (R), color data (R)
Is also used as color data (G) and color data (B).

(B) When gradation display data other than black and white (monotone) is received from the computer main body 11 (main machine side): The liquid crystal display device 12 uses all the plurality of gradation display data included in the display data 13 as gradation display data. Color data (for example, color data (R), color data (G) and color data (B)) are received.

(Second Embodiment) As shown in FIG.
The liquid crystal display device 12 includes a display data line group 13a for receiving color data (R), a display data line group 13b for receiving color data (G), and a display data line group for receiving color data (B). It has a group 13c, a signal line 14a for receiving the clock signal 14, and a signal line 15a for receiving the synchronization signal 15. When each of the color data (R), the color data (G) and the color data (B) consists of 6 bits, the display data line group 13a
Each of 13 to 13c consists of 6 signal lines. The liquid crystal display device 12 further includes a control signal line 16a for receiving the color data control signal 16. In FIG. 2, R
0 to R5 indicate each bit that constitutes 6-bit color data (R), and G0 to G5 indicate 6-bit color data (G).
, And each of B0 to B5 represents each bit of 6-bit color data (B).

When the liquid crystal display device 12 performs gray scale display of black and white (monotone), the color data (R), the color data (G) and the color data (B) have the same value. For example, when the values of the color data (R), the color data (G), and the color data (B) are all “000000”, the gradation to be displayed on the liquid crystal display device 12 is “black”. Indicates. When the values of the color data (R), the color data (G), and the color data (B) are all “111111”, it indicates that the gradation to be displayed on the liquid crystal display device 12 is “white”. . When the values of the color data (R), the color data (G), and the color data (B) are all “010101”, it indicates that the gradation to be displayed on the liquid crystal display device 12 is “gray”. .

Thus, when the color data (R), the color data (G) and the color data (B) have the same value, the computer main body 11 sets the level of the color data control signal 16 to "H". The "H" level color data control signal 16 and only the color data (R) are transmitted to the liquid crystal display device 12. The color data transmitted from the computer main body 11 to the liquid crystal display device 12 may be any one of the plurality of color data, and is not limited to the color data (R). However, the color data to be transmitted among the plurality of color data is determined by the computer main body 11 and the liquid crystal display device 1.
It should be agreed in advance with 2.

FIG. 3 shows the timing of data transmitted from the computer main body 11 to the liquid crystal display device 12 when the level of the color data control signal 16 is "H" level. This transmission is based on the VGA specification. In FIG. 3, as indicated by *, only the color data (R) of the display data is transmitted from the computer main body 11 to the liquid crystal display device 12.

When color gradation display is performed on the liquid crystal display device 12, the color data (R), the color data (G) and the color data (B) do not always have the same value. The transmission from the computer main body 11 to the liquid crystal display device 12 in this case is the same as the conventional transmission. That is,
The computer main body 11 transmits the color data (R), the color data (G), and the color data (B) to the liquid crystal display device 12. Further, the computer main body 11 sets the level of the color data control signal 16 to the “L” level, and transmits the “L” level color data control signal 16 to the liquid crystal display device 12.

The operation of the liquid crystal display device 12 will be described below with reference to FIG.

The liquid crystal display device 12 receives the color data control signal 16 via the control signal line 16a. The level of the color data control signal 16 is either "H" level or "L" level. The liquid crystal display device 12 determines whether the level of the color data control signal 16 is “H” level.

When the level of the color data control signal 16 is "H" level, the liquid crystal display device 12 transmits a plurality of colors through one display data line group among the display data line groups 13a to 13c. Receive color data of one of the data. Which color data of the plurality of color data is to be received is determined in advance between the computer main body 11 and the liquid crystal display device 12. For example, the liquid crystal display device 12 uses the color data (R) through the display data line group 13a.
Receive only. In this case, the color data (G) and the color data (B) are transferred from the computer main body 11 to the liquid crystal display device 12.
Not transmitted to.

The fact that the level of the color data control signal 16 is "H" level indicates that the color data (R), the color data (G) and the color data (B) have the same value. The liquid crystal display device 12 creates color data (G) and color data (B) having the same values as the color data (R) based on the color data (R) received from the computer main body 11. Alternatively, the actual color data (G) and color data (B)
The color data (R) is supplied as color data (G) to the display unit 20 (FIG. 1) and the color data (R) is displayed as color data (B) on the display unit 20 (FIG. 1) without creating It may be supplied.

When the level of the color data control signal 16 is "L" level, the liquid crystal display device 12 receives the color data (R) through the display data line group 13a and receives through the display data line group 13b. To receive the color data (G) and the color data (B) via the display data line group 13c. The color data (R), the color data (G), and the color data (B) received in this way are displayed on the display unit 20 (FIG. 1).
Is supplied to.

As shown in FIG. 4, the liquid crystal display device 12
Includes a switch circuit 22. In the switch circuit 22,
The color data control signal 16 is input. Switch circuit 22
Determines whether or not the level of the color data control signal 16 is "H" level.

When the level of the color data control signal 16 is "H" level, the switch circuit 22 electrically connects the display data line group 13a and the signal lines G00 to G05, and the display data line group 13a. And the signal lines B00 to B05 are electrically connected. The signal lines G00 to G05 are used to supply color data (G) to the display unit 20 (FIG. 1). The signal lines B00 to B05 are used to supply the color data (B) to the display unit 20 (FIG. 1). As a result, the color data (G) and the color data (B) having the same values as the color data (R) received via the display data line group 13a are supplied to the display unit 20 (FIG. 1). The display data line group 13a is always electrically connected to the signal lines R00 to R05. As a result, the display unit 20 performs multicolor display based on the color data (R), the color data (G), and the color data (B).

When the level of the color data control signal 16 is "L" level, the switch circuit 22 electrically connects the display data line group 13b and the signal lines G00 to G05, and the display data line group 13c. And the signal lines B00 to B05 are electrically connected. The display unit 20 performs multicolor display based on the color data (R), the color data (G), and the color data (B).

As described above, when the level of the color data control signal 16 is "L" level, 6 bits × 3 are displayed through a total of 18 signal lines (display data line groups 13a to 13c). Data is transmitted from the computer main body 11 to the liquid crystal display device 12. On the other hand, when the level of the color data control signal 16 is the “H” level, a total of 7 signal lines of 6 bits + 1 bit (display data line group 13a
Display data is transmitted from the computer main body 11 to the liquid crystal display device 12 via the control signal line 16a). This reduces EMI. In particular, when the color data (R), the color data (G), and the color data (B) are all 6 bits or more (when multi-color display is further performed), the EMI reduction effect according to the present invention is drastic. Appear in. At the same time, low power consumption can be achieved.

Further, even when black and white (monotone) gradation display occupies most of the screen, the effect of reducing EMI according to the present invention is very large. For example, in the work screen of a word processor using a computer, most of the screen is sufficient to display in black and white (monotone). Therefore, according to the present invention, E
It will be understood that the effect of reducing MI is very large.

In the above, the computer main body has been described as the main machine based on the computer equipped with the liquid crystal display device which has been attracting attention as a display device replacing the conventional CRT, but the present invention is not limited to this, and the main machine is used. The present invention can be applied to a device or a product in which display data is sent to the display device side.

[0065]

The greatest effect of the present invention is that unnecessary radiation can be greatly reduced and power consumption can be reduced. Even if each color data has a high gradation of 6 bits or 8 bits or more, the effect of reducing EMI can be expected at a low cost. Further, the present invention relates to data transmission technology to a display device, such as a liquid crystal display device, a plasma display device,
It is also used for data transmission to flat display devices such as EL display devices and field effect display devices (FED).

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a computer 10 according to the present invention.

2 is a diagram for explaining details of color data transmitted from the computer main body 11 to the liquid crystal display device 12. FIG.

FIG. 3 is a diagram showing timing of data transmitted from the computer main body 11 to the liquid crystal display device 12.

FIG. 4 is a diagram for explaining the operation of the liquid crystal display device 12.

FIG. 5 is a diagram showing a configuration of a conventional computer 50.

FIG. 6 is a diagram for explaining details of color data transmitted from the computer main body 51 to the liquid crystal display device 52.

7 is a diagram showing the timing of data transmitted from the computer main body 51 to the liquid crystal display device 52. FIG.

FIG. 8 is a diagram showing a relationship between color data, a display basic color, and a brightness gradation of each color.

FIG. 9: VGA specification (dot structure: 640 × RGB × 4)
It is a figure which shows the input signal (display data) and screen display in 80).

[Explanation of symbols]

 10 computer 11 computer main body 12 liquid crystal display device 13 display data 14 clock signal 15 synchronization signal 16 color data control signal 20 display unit 50 computer 51 computer main body 52 liquid crystal display device

Claims (8)

[Claims] 1. A method of transmitting a plurality of color data defining a plurality of color components respectively from a main machine side to a display device, wherein the plurality of color data have the same value. A first transmission step of transmitting one color data of the data and a color data control signal having a first level from the main unit side to the display device; and when the plurality of color data have different values, A second transmitting step of transmitting the plurality of color data and a color data control signal having a second level different from the first level from the master unit to the display device. 2. The method according to claim 1, wherein the plurality of color data includes color data representing red, color data representing green, and color data representing blue. 3. The first transmission step comprises setting a signal line corresponding to color data other than the one color data transmitted in the first transmission step to high impedance, and the first transmission step. 3. The method according to claim 1, further comprising the step of maintaining a potential of a signal line corresponding to color data other than the one color data transmitted in step 1 at a constant level. 4. The method of claim 3, wherein the constant level is either a high level or a ground level. 5. A display device connected to the main engine side,
A method of displaying an image having a plurality of gradations based on a plurality of color data defining a plurality of color components, wherein a color data control signal is received and the level of the color data control signal is a predetermined level. Determining whether or not the color data control signal is at the predetermined level, receives one color data from the plurality of color data, and converts the received one color data into the received one color data. Based on the received color data, and displaying the image having a plurality of gradations based on the received one color data and the created color data. And including. 6. The method of claim 5, wherein the plurality of color data includes color data representing red, color data representing green, and color data representing blue. 7. A device which is connected to a main machine side and which displays an image having a plurality of gradations based on a plurality of color data defining a plurality of color components, the device receiving a color data control signal, and receiving the color data control signal. A means for determining whether or not the level of the data control signal is at a predetermined level, and one color data of the plurality of color data when the level of the color data control signal is at the predetermined level. Means for creating the remaining color data of the plurality of color data based on the received one color data, and based on the received one color data and the created color data, A device for displaying an image having a plurality of gradations. 8. The apparatus according to claim 7, wherein the plurality of color data includes color data representing red, color data representing green, and color data representing blue.