JP2002221952A - Image data transmission method, and image display system and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image data transmission method which enables the transmition of image data with super-high resolution and an image display system using the method. SOLUTION: Image data whose refresh frequency is set lower than a refresh frequency displayed on a liquid crystal display 205 are transmitted to a display device 201 from a host device 200. The received image data whose refresh frequency is lowered are stored into a frame memory 214 in the display device 201. The refresh frequency of image data is raised by reading the same image data multiple times when reading image data from the frame memory 214, thereby displays the image data with super-high resolution on the liquid crystal display 205.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a computer device (host device), a display device (display device),
The present invention relates to an image data transmission method used in a video interface connecting a host device and a display device, and an image display system and a display device using the image data transmission method.

[0002]

2. Description of the Related Art As an example of the prior art, an image display system in which a personal computer and a CRT display are connected by a video cable will be described.

[0003] The image display system, as shown in FIG.
A host device 100, a display device 101, and a video interface 104 connecting the host device 100 and the display device 101 are provided. The host device 100 includes a graphics control circuit 102 for transmitting image data to the video interface 104.
It has. The display device 101 receives the image data from the host device 100 and displays the image data on the CRT display 1.
05 has a CRT display control circuit 103 for controlling image display. The image data transmitted from the host device 100 is transmitted to the display device 101 via the video interface 104.

The graphics control circuit 102 has a D / A
Graphics controller 10 with converter 109
6 and a graphics memory 107. The graphics controller 106
In accordance with a drawing command input from a CPU (Central Processing Unit) in a personal computer device via a system bus 108, a graphics memory 107 is used to perform arithmetic processing to generate image data.

In the graphics controller 106, the generated image data is converted into an analog RGB signal by a D / A converter 109 provided in the graphics controller 106, and a horizontal synchronization signal and a vertical synchronization signal are added thereto. From the video output connector 110 to the video input connector 112
Are sequentially output to

At this time, the refresh frequency corresponding to the vertical synchronizing signal of the image data is determined by the display device 101.
The frame frequency is adjusted to the frame frequency of the CRT display 105 in the inside, and is generally 50 Hz to 70 Hz.

[0007] The video interface 104 transmits an analog video signal output from the video output connector 110 to the video input connector 112 via the video cable 111.

The analog video signal transmitted from the video interface 104 is transmitted to the CRT display control circuit 1
In step 03, the data is converted into a data format suitable for CRT control, sequentially output to the CRT display 105, and an image is displayed.

However, in the above-described conventional configuration, when image data having a resolution of, for example, 3200 × 2400 dots is transmitted from the host device 100 to the display device 101 at a refresh frequency of 60 Hz, the graphics controller 106 D / A within
When the converter 109 converts the image data into an analog RGB signal, the conversion clock frequency becomes 500 MHz or higher.
01 is extremely difficult to transmit.

Therefore, in order to solve the above problems,
In a transmission method for transmitting image data from a host device to a display device, the image data transmission is performed by transmitting image data in parallel using a plurality of image data transmission cables for transmitting image data from the host device. A configuration for lowering the frequency has been proposed in Japanese Patent Application Laid-Open No. 8-181958.

In the above configuration, since the analog video signals are transmitted in parallel using a plurality of image data transmission cables, the data transfer clock frequency of the image data can be reduced. Therefore, it is possible to suppress the conversion clock frequency for converting the image data into the analog RGB signal, thereby transmitting the ultra-high resolution image data to the display device.

[0012]

However, in the above-described conventional configuration, the method of transmitting image data is limited only to the case of transmitting an analog video signal, and does not describe a method of transmitting a digital video signal. .
Further, since a plurality of systems of image data transmission cables necessary for transmitting image data to the display device are used, the cable diameter becomes large, making it difficult to use. In addition, a device for transmitting and receiving image data using a plurality of systems of cables is required, which causes problems such as a high cable cost and a high device cost.

On the other hand, when image data is transmitted as a digital video signal without being converted into an analog RGB signal, it is necessary to use a plurality of existing digital video transmitting / receiving devices and connect them in parallel with a multi-core cable. However, there is a problem that the cable diameter becomes large and it is difficult to use, or the cost of the video interface increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to transmit a refresh frequency of image data from a host device to a display device lower than a refresh frequency displayed on a display unit. Accordingly, an object of the present invention is to provide an image data transmission method which enables transmission of ultra-high-resolution image data by transmitting at a reduced data transfer clock frequency and increasing a refresh frequency in a display device. Another object is to provide an image display system and a display device using the image data transmission method.

[0015]

According to a first aspect of the present invention, there is provided an image data transmission method comprising the steps of: transmitting image data having a refresh frequency set from a host device to a display device; A second step of temporarily storing the received image data of the refresh frequency in a storage means provided in the display device, and, when reading the image data from the storage means, increasing the refresh frequency of the image data to increase the image data. And a third step of displaying data.

According to the above arrangement, when transmitting image data to the display device, the refresh frequency of the image data received by the display device can be increased while transmitting the image data while suppressing the refresh frequency. Therefore, image data can be transmitted with the data transfer clock frequency suppressed. Further, by increasing the refresh frequency of the image data received by the display device, an image without flicker can be displayed on the display unit. This makes it possible to transmit ultra-high-resolution image data, which is extremely difficult with the conventional configuration.

Further, according to the above configuration, in the D / A converter, the conversion clock frequency when converting the image data into the analog RGB signal can be suppressed, thereby burdening the D / A converter. It is possible to transmit the image data without using it and without increasing the number of cables for transmitting the image data.

In the image data transmission method according to the present invention, in order to solve the above-mentioned problem, the third step is that, when reading out image data from the storage means, the refresh frequency is set to n times (n = 2) that at the time of transmission. (The above natural number).

According to the above configuration, the refresh frequency at the time of display is set to an integral multiple of the refresh frequency at the time of transmission, so that when the content of the image data of the host device is rewritten, the image displayed on the display unit is also changed. Since the image is rewritten in synchronization, it is possible to prevent an image in one frame from being changed from the middle to the next image and displayed on the display unit.

According to the image data transmission method of the present invention, in order to solve the above-mentioned problem, the third step is to divide the image data into a plurality of screen areas when reading the image data from the storage means. The image data is read out by increasing the refresh frequency of the image data for each divided area, and the image is displayed on each display unit.

According to the above arrangement, it is possible to transmit ultra-high resolution image data to a plurality of screen areas.

In order to solve the above-mentioned problems, an image display system according to the present invention transmits image data generated by a host device to a display device at a predetermined refresh frequency, and transmits the image data to a display unit of the display device. In the image display system for displaying, the display device is configured to temporarily store image data received from the host device, and to transmit image data stored in the storage device from the host device to the display device. And a control means for reading out the read image data on the display unit at a refresh frequency higher than the refresh frequency.

According to the above configuration, since the image data is transmitted to the display device with the refresh frequency set to be low, the image data can be transmitted with the data transfer clock frequency kept low. Also, by increasing the refresh frequency of the received image data in the display device,
It is possible to provide an image display system capable of displaying an image without flicker and displaying image data of ultra-high resolution.

Further, according to the above configuration, in the D / A converter, the conversion clock frequency for converting the image data into the analog RGB signal can be suppressed. Thus, image data can be transmitted without imposing a load on the D / A converter. Therefore, it is possible to provide an image display system that can transmit ultra-high-resolution image data, which is extremely difficult with the conventional configuration.

In the image display system according to the present invention, in order to solve the above-mentioned problem, the control means sets the refresh frequency to n times (n = 2 or more natural number) at the time of transmission when reading image data from the storage means. ).

According to the above configuration, the refresh frequency at the time of display is set to an integral multiple of the refresh frequency at the time of transmission, so that when the content of the image data of the host device is rewritten, the image displayed on the display unit is also changed. Rewritten synchronously. Therefore, it is possible to provide an image display system that can prevent an image in one frame from being changed from the middle to the next image and displayed on the display unit.

In the image display system according to the present invention, in order to solve the above-mentioned problems, the control means divides the image data into a plurality of screen areas when reading the image data from the storage means. It is characterized in that the refresh frequency of the image data is increased for each region and the image data is read out and displayed on each display unit.

According to the above arrangement, the image data is read out by increasing the refresh frequency for each of the divided areas and displayed on the respective display sections. For example, a plurality of low-resolution display devices having a low data transfer clock frequency are provided. It is possible to provide an image display system that can display an ultra-high resolution image by using a table. Further, it is also possible to provide an image display system capable of displaying a different image for each divided area.

In order to solve the above-mentioned problems, the image display system of the present invention is characterized in that transmission of image data from the host device to the display device is performed by a digital video interface.

According to the above configuration, since the video interface is of a digital type, it is possible to provide an image display system which does not need to convert image data into an analog video signal once and does not deteriorate the image data. it can.

In order to solve the above-mentioned problems, a display device according to the present invention includes a storage unit for temporarily storing image data transmitted from a host device, and a refresh operation for refreshing image data when reading the image data from the storage unit. Control means for increasing the frequency.

According to the above arrangement, when reading out the stored image data from the storage means, the refresh frequency of the image data is increased and displayed, whereby an ultra-high-resolution image without flicker can be displayed. A display device can be provided.

In order to solve the above-mentioned problems, the display device of the present invention is arranged such that the control means sets the refresh frequency to n times (n = 2 or more natural number) the transmission frequency when reading the image data from the storage means. It is characterized in that it is set to increase.

According to the above configuration, by setting the refresh frequency at the time of display to be an integral multiple of the refresh frequency at the time of transmission, when the content of the image data of the host device is rewritten, the image displayed on the display device is also reduced. Rewritten synchronously. Therefore, it is possible to provide a display device that can prevent an image in one frame from being displayed in the middle of being changed to the next image.

In the display device according to the present invention, in order to solve the above-mentioned problem, the control means divides the image data into a plurality of screen areas when reading the image data from the storage means, and Each time the refresh frequency of the image data is increased, the image data is read out and displayed on each display unit.

According to the above configuration, there is provided a display device capable of displaying an ultra-high resolution image by reading out image data at a higher refresh frequency for each divided area and displaying the image data on each display unit. can do.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] An embodiment of the present invention will be described with reference to FIGS.
It is as follows.

The image display system according to the present embodiment sets the refresh frequency of the image data lower than the refresh frequency displayed on the display unit and transmits the data to the display device, thereby suppressing the data transfer clock frequency, and thereby reducing the data transfer clock frequency. By increasing the refresh frequency of the image data by the control means, it is possible to display an ultra-high-resolution image without flicker on the display unit.

The image display system, as shown in FIG.
Host device 200, display device (display device) 20
1 and a video interface 204 connecting the host device 200 and the display device 201. Examples of the host device 200 include a personal computer and a workstation. The image data transmitted from the host device 200 is transmitted to the display device 201 via the video interface 204.

The host device 200 has a graphics control circuit 202 for transmitting image data to the video interface 204.

The graphics control circuit 202 has a D / A
Graphics controller 20 with converter 209
6 and a graphics memory 207.

The graphics controller 206 is a CPU (central processing unit) in a personal computer.
Image data is generated by performing arithmetic processing using the graphics memory 207 in accordance with a drawing command input from the system bus 208 via the system bus 208.

The display device 201 has a liquid crystal display control circuit (control means) 203 for receiving image data from the video interface 204 and displaying an image on a liquid crystal display (display unit) 205.

The video interface 204 connects the host device 200 and the display device 201, and converts an analog video signal output from the video output connector 210 of the host device 200 into a video cable 2.
11 to the video input connector 212 on the display device 201 side.

The details of the liquid crystal display control circuit 203 are as shown in FIG. 2. The A / D converts an analog video signal transmitted from the host device 200 into a digital video signal.
A converter 213, a write control circuit 217 for controlling timing of writing image data (digital video signal) to the frame memory, a frame memory A 215 and a frame memory B 216 for temporarily storing transmitted image data, A memory selection control circuit 218 for selecting a frame memory when writing data, and a read control circuit 219 for controlling read timing when reading image data from the frame memory.

An example of a method of transmitting image data in the image display system having the above configuration will be described below.

The image data generated in the graphics controller 206 is, for example, 3200
× 2400 dots, the refresh frequency is 26 Hz. This refresh frequency is set in a control register (not shown) in the graphics controller 206.

The generated image data is converted to an analog RGB signal by a D / A converter 209 in the graphics controller 206, and converted into a video output connector as an analog video signal to which a horizontal synchronizing signal and a vertical synchronizing signal are added. The refresh frequency is sequentially output to the video interface 210 and transmitted to the video input connector 212 via the video interface 204 while the refresh frequency is set to be low.

The analog video signal, that is, the image data transmitted to the video input connector 212 is transmitted to the liquid crystal display control circuit 203 and is converted into a digital video signal by the A / D converter 213.
7 is written and stored in the frame memory A 215 or the frame memory B 216 at a refresh frequency of 26 Hz.

When the stored image data is read out from the frame memory A 215 or the frame memory B 216, the refresh frequency of the image data is read out, for example, at 60 Hz through the read control circuit 219.
The data is converted into a data format suitable for the liquid crystal display control, sequentially output to the liquid crystal display 205, and an image is displayed.

Control of the timing of writing and reading of image data is performed by a memory selection control circuit 218 as shown in FIG.

Tx_DATA indicates image data converted into a digital video signal by the A / D converter 213, and Tx_VS indicates a vertical synchronizing signal of the image data. MA_Data is the frame memory A 215
2 shows image data to be read and written. MB_Da
“ta” indicates image data read and written to the frame memory B 216. MA_R / W * is a write / read control signal for the frame memory A215,
R / W * indicates a write / read control signal for the frame memory B216. When the control signal is at a high level, it indicates a data reading period, and when the control signal is at a low level, it indicates a data writing period. Rd_DATA indicates image data output to the liquid crystal display 205, and Rd_VS indicates a vertical synchronization signal of the image data.

The image data transmission method according to the present embodiment is performed every 38.46 msec (refresh frequency 26 Hz corresponding to the vertical synchronization signal), which is the period of the vertical synchronization signal of the image data input to the liquid crystal display control circuit 203. ,
The frame memory A 215 and the frame memory B 216 for writing image data are alternately switched, and the frame memory A 215 and the frame memory B 216 for 16.67 msec.
(Refresh frequency 60H corresponding to vertical synchronization signal
The image data to be output to the liquid crystal display 205 is read every z).

Specifically, for example, from the host device,
X, A, B, C, D image data is 38.46 ms
When the image data A is transmitted sequentially in the cycle of every ec, the memory selection control circuit 218 writes the image data A to the frame memory A 215 and the frame memory B 216 at the same time when the image data A is transmitted. The read image data X is read every 16.67 msec, and the display device displays the image data X.

Next, when the image data B is transmitted, the memory selection control circuit 218 switches a memory write selection switch (not shown) and a memory read selection switch (not shown), and Is written in the image data B. At the same time, the memory selection control circuit 218 uses the frame memory A 215 in the previous cycle.
The image data A written at 16.67 msec
Each time, the image data A is displayed on the display device. The same operation is performed on the image data B, C, and D to display an image on the liquid crystal display 205. That is, the memory selection control circuit 218 writes the image data in one frame memory and at the same time, reads the image data written in the previous cycle from the other frame memory.

That is, the refresh frequency is 26 Hz
16.67 ms within the period of 38.46 msec, which is the time until the next image data is read out,
Read multiple times for each ec. As a result, image data (Rd_DATA) having a higher refresh frequency is created. That is, the image data (Rd_DATA) is output to the liquid crystal display 205 as a vertical synchronization signal (Rd_VS) obtained by increasing the frequency of the vertical synchronization signal (Tx_VS) transmitted from the video interface 204. As a result, image data with a refresh frequency of 60 Hz is created, and an ultra-high-resolution image display without flicker is enabled.

In this embodiment, the method of increasing the refresh frequency by using the memory selection control circuit 218 has been described. However, the refresh frequency can be adjusted by using a circuit for controlling arbitration of writing and reading to and from the frame memory. It may be raised, and it is not limited only to the method exemplified above.

Also, in the present embodiment, the display section
The liquid crystal display has been described.
Examples thereof include an RT display and a plasma display, and are not particularly limited.

In this embodiment, an example in which the refresh frequency of the image data is increased to 60 Hz has been described. However, the refresh frequency is increased according to the frame frequency of the display, and is not particularly limited.

In this embodiment, an analog video interface is used as the video interface 204, but a digital video interface may be used, and there is no particular limitation.

As described above, in the image data transfer method according to the present embodiment, the step of transmitting image data having a refresh frequency set lower than the refresh frequency displayed on the liquid crystal display 205 from the host device 200 to the display device 201. Receiving the image data of the refresh frequency and temporarily
1 and displaying the image data on the liquid crystal display 205 by increasing the refresh frequency of the image data by the memory selection control circuit 218 and the read control circuit 219 when reading the image data from the frame memory 214. And a step of performing

According to the above configuration, when transmitting image data from the host device 200 to the display device 201, the refresh frequency is set lower than the refresh frequency of the image data displayed on the liquid crystal display 205, and transmitted to the display device 201. By doing so, it is possible to transmit image data while suppressing the data transfer clock frequency. Further, by increasing the refresh frequency of the image data received by the display device 201, an image without flicker can be displayed.

In the conventional configuration, the refresh frequency is constant between transmission and display. However, in the present embodiment, the host device 200 transmits image data lower than the display refresh frequency. Then, the refresh frequency is increased on the display device side. Therefore, in the conventional configuration, the data transfer clock frequency is suppressed by increasing the number of video cables, but in the present embodiment, the image data is transmitted at a low data transfer clock frequency without increasing the number of video cables 211. , The electromagnetic interference can be suppressed, the cost can be suppressed, and there is no problem such as the cable becoming thick and difficult to use.

[Second Embodiment] The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members (structures) having the same functions as the members (structures) shown in the drawings of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The image display system according to the present embodiment is the same as that of the first embodiment, and a detailed description is omitted.

The image data generated in the graphics controller 206 is specifically, for example, 3200
× 2400 dots, and the refresh frequency is 30 Hz. This refresh frequency is set in a control register in the graphics controller 206. The image data generated by the graphics controller 206 is converted into an analog RGB signal by a D / A converter 209, and is sequentially output from a video output connector 210 as an analog video signal to which a horizontal synchronization signal and a vertical synchronization signal are added. The output is transmitted to the video input connector 212 via the video interface 204 while the refresh frequency is suppressed.

An analog video signal, that is, image data, transmitted to the video input connector 212 is transmitted to the liquid crystal display control circuit 203 and is converted into a digital video signal by the A / D converter 213.
The data is written to and stored in the frame memory A 215 or the frame memory B 216 at 17 Hz through 17.

The image data written and stored in the frame memory A 215 or the frame memory B 216 is read out through the memory selection control circuit 218 when read out.
The data is read out at Hz, converted into a data format suitable for liquid crystal display control, sequentially output to the liquid crystal display 205, and an image is displayed.

The timing control of writing and reading of image data is performed by the memory selection control circuit 218 as shown in FIG.

Tx_DATA and Tx_VS are A / D
The figure shows the image data and the vertical synchronizing signal converted into the digital video signal by the converter 213. MA_Data
Indicates image data read and written to the frame memory A215. MB_Data is the frame memory B
Reference numeral 216 denotes image data to be read and written. MA
_R / W * is a write / read control signal for the frame memory A 215, MB_R / W * is a write / read control signal for the frame memory B 216. When the control signal is at a high level, the data read period is set. The low level indicates a data writing period.
Rd_DATA and Rd_VS are the liquid crystal display 20
5 shows image data and a vertical synchronization signal output.

In the image data transmission method according to the present embodiment, the period of the vertical synchronization signal (Tx_DATA) of the image data input to the liquid crystal display control circuit 203 is 33.3.
The frame memory A 215 and the frame memory B 216 for writing image data are alternately switched every 3 msec (refresh frequency 30 Hz corresponding to the vertical synchronization signal), and 16.67 msec (for the vertical synchronization signal) from the frame memory on which writing is not performed. The image data to be output to the liquid crystal display 205 is read out at each corresponding refresh frequency of 60 Hz.

Specifically, for example, from the host device,
X, A, B, C, D image data is 33.33 ms
When the image data A is transmitted sequentially in the cycle of every ec, the memory selection control circuit 218 writes the image data A in the frame memory A 215 and in the frame memory B 216 in the previous cycle at the time of transmitting the image data A. The read image data X is read out every 16.67 msec, and the display device displays the image data X.

Next, when the image data B is transmitted, the memory selection control circuit 218 switches a memory write selection switch (not shown) and a memory read selection switch (not shown), and Is written in the image data B. At the same time, the memory selection control circuit 218 uses the frame memory A 215 in the previous cycle.
The image data A written at 16.67 msec
Each time, the image data A is displayed on the display device. The same operation is performed on the image data B, C, and D to display an image on the liquid crystal display 205. That is, the memory selection control circuit 218 writes the image data in one frame memory and at the same time, reads the image data written in the previous cycle from the other frame memory.

That is, the refresh frequency is 30 Hz
16.67 ms within the period of 33.33 msec, which is the time until the next image data is read out,
Read twice for each ec. As a result, image data (Rd_DATA) whose refresh frequency has been doubled is created. That is, the image data (Rd_DATA)
Is output to the liquid crystal display 205 as a vertical synchronization signal (Rd_VS) in which the frequency of the vertical synchronization signal (Tx_VS) transmitted from the video interface 204 is doubled. As a result, the refresh frequency of the image data becomes 60 Hz, which is twice the refresh frequency of the image data transmitted from the host device 200.
Therefore, it is possible to display an ultra-high-resolution image without flicker.

As described above, in the configuration of the second embodiment, the refresh frequency of the image data when reading the image data from the frame memory 214 is set to n times (n = 2 or more) the refresh frequency at the time of transmitting the image data. Natural number of
Embodiment 1 is different from Embodiment 1 in that As a result, in the configuration of the second embodiment, the following effects can be obtained.

That is, in the configuration of the first embodiment, the refresh frequency of the image data when reading the image data from the frame memory 214 is n times (n = 2 or more natural number) the refresh frequency at the time of transmitting the image data. Therefore, the moment when the display of the image data is switched is in the middle of the screen. This is specifically described below with reference to FIG.

In FIG. 3, considering the moment when the display is switched from the image data X to the image data A, at this moment, during the third reading of the image data X, the memory of the memory selection control circuit 218 is read. The write select switch and memory read select switch are switched,
The image data A is read.

At this time, assuming that the reading up to the n-th line of the display has been completed in the reading of the image data X immediately before the switching of the display, the image data A to be subsequently read is obtained in order to obtain the vertical synchronization of the display image. To (n +
1) Reading from the line needs to be performed. Therefore, in this case, the image data X
Therefore, there is a problem that an image whose remaining screen is the image data A is displayed, which leads to a decrease in image quality.
In addition, since image data read immediately after the display is switched is read from the middle of the data, there is a problem in that control related to data reading becomes complicated.

On the other hand, in the configuration of the second embodiment,
When reading image data from the frame memory 214,
By setting the refresh frequency to, for example, n times the refresh frequency at the time of transmission (n is a natural number of 2 or more), writing and reading to and from the frame memory 214 are synchronized. Is not rewritten to another image in the middle of the process, and the reading of the image data from the middle of the data does not occur. Thus, in the configuration of the second embodiment, it is possible to avoid problems such as deterioration in image quality due to switching of display in the middle of a screen and complicated control due to reading of image data in the middle of data.

In this embodiment, as a method of increasing the refresh frequency, the memory selection control circuit 21
Although the method of increasing the refresh frequency has been described using FIG. 8, the refresh frequency may be increased by using a circuit or the like that arbitrates control of writing and reading to and from the frame memory, and is not limited to the above-described method. Absent.

In this embodiment, as a method of synchronizing the writing and reading with respect to the frame memory, when reading the image data from the frame memory, the refresh frequency is twice the refresh frequency at the time of transmission. The refresh frequency at the time of displaying an image may be an integer multiple of the refresh frequency at the time of transmission, and is not particularly limited.

In the present embodiment, the display section
The liquid crystal display has been described.
Examples thereof include an RT display and a plasma display, and are not particularly limited.

As described above, according to the method of transferring image data according to the present embodiment, the host device 200 transmits image data lower than the refresh frequency to be displayed on the liquid crystal display 205 to the display device 201; Receiving the image data with the reduced refresh frequency and temporarily storing the image data in the frame memory 214 in the liquid crystal display control circuit 203, and transmitting the refresh frequency of the image data when reading the image data from the frame memory 214. N times (n = natural number of 2 or more) times the display device 20
1 for displaying an image.

According to the above configuration, when transmitting image data to the display device 201, the image data is transmitted with the refresh frequency suppressed, and the image data can be transmitted with the data transfer clock frequency suppressed. . Further, by increasing the refresh frequency of the image data received by the display device, an image without flicker can be displayed.

Further, since image data can be transmitted at a low data transfer clock frequency without increasing the number of cables, electromagnetic interference can be suppressed, cost can be reduced, and the cable can be made thicker. There is no problem such as difficulty in use.

Further, according to the above configuration, when the content of the image data of the host device 200 is rewritten, the image displayed on the liquid crystal display 205 is also rewritten synchronously, so that the image in one frame is changed from the middle. This prevents the next image from being displayed on the display unit.

[Third Embodiment] The following will describe another embodiment of the present invention with reference to FIGS. For convenience of explanation, members (structures) having the same functions as the members (structures) shown in the drawings of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The image display system according to the present embodiment sets the refresh frequency of the image data lower than the refresh frequency displayed on the display unit and transmits the refresh data to the display device, thereby suppressing the data transfer clock frequency and thereby reducing the data transfer clock frequency. By increasing the refresh frequency by the control means, flicker-free super-high-resolution image data is divided and displayed on a plurality of liquid crystal displays.

The image display system, as shown in FIG.
Host device (personal computer device) 300, display device (display device) 301, and host device 3
00 and a display device 301. Host device 30
The image data transmitted from 0 is transmitted to the display device 301 via the video interface 304.

The host device 300 has a graphics control circuit 302 for transmitting image data to the video interface 304. The graphics control circuit 302 has a graphics controller 309 and a graphics memory 310. .

The display device 301 has a liquid crystal display control circuit 303 (control means) for receiving image data from the graphics controller 309 and displaying an image on the liquid crystal displays 305 to 308 (display section) and liquid crystal displays 305 to 308. are doing. The liquid crystal display control circuit 303 includes a screen division control circuit 318 and the host device 3.
A frame memory (storage means) 317 for temporarily storing the image data transmitted from 00 is provided.

The video interface 304 transmits a digital video signal output from the digital video transmitting device 312 to the digital video receiving device 316 via the video output connector 313, the video cable 314, and the video input connector 315.

The graphics controller 309 is a CPU (central processing unit) in a personal computer.
In accordance with a drawing command inputted from the system via the system bus 311, arithmetic processing is performed using the graphics memory 310 to generate image data.

An example of a method of transmitting image data in the image display system having the above configuration will be described below.

First, the image data is converted by the graphics controller 309 into a digital video signal including a digital RGB signal, a horizontal synchronizing signal, a vertical synchronizing signal, and a data enable signal for controlling the screen division control circuit 318.

The above image data (digital video signal)
Has a resolution of, for example, 3200 × 2400 dots and a refresh frequency of 20 Hz. This setting is performed by a control register in the graphics controller 309. The refresh frequency is one third of the frame frequency of the liquid crystal displays 305 to 308 used in the display device 301.

Next, the graphics controller 309
Are transmitted from the video output connector 313 to the video input connector 315 sequentially through the digital video transmission device 312.

Next, the digital video signal transmitted to the video input connector 315 is written and stored in the frame memory 317 in the liquid crystal display control circuit 303 through the digital video receiving device 316.

The digital video signal stored in the frame memory 317, that is, image data of 3200 × 2400 dots and a refresh frequency of 20 Hz transmitted from the host device 300 is sent to the screen division control circuit 318 in the liquid crystal display control circuit 303. As shown in FIG. 7, for example, the data is divided into four regions of 1600 × 1200 dots, read from the frame memory 317 at each of the liquid crystal displays 305 to 308 at an increased refresh frequency, and is suitable for liquid crystal display control. The images are converted into a format and sequentially output to the respective liquid crystal displays 305 to 308 to display an image.

The resolution of the image data read to each of the liquid crystal displays 305 to 308 is, for example, 1600.
× 1200 dots, and the refresh frequency is 60 Hz. This refresh frequency is 3 times the refresh frequency of the image data transmitted from the host device 300.
As shown in FIG. 6, the image data transmitted from the host device 300 and the images displayed on the liquid crystal displays 305 to 308 are synchronized.

Tx_DATA and Tx_VS are transmitted by the video interface 304
It shows image data of 0 × 2400 dots and a vertical synchronization signal. Rd_DATA0 and Rd_VS0 are image data and a vertical synchronization signal read from the frame memory 317 for the liquid crystal display 305, and Rd_DATA1.
Rd_VS1 and Rd_VS1 are image data and a vertical synchronization signal read from the frame memory 317 for the liquid crystal display 306, Rd_DATA2 and Rd_VS2 are image data and a vertical synchronization signal read from the frame memory 317 for the liquid crystal display 307, and Rd_DATA3 and Rd_VS3 are a liquid crystal display 308. 5 shows image data and a vertical synchronizing signal read from the frame memory 317.

In the image data transmission method according to the present embodiment, as shown in FIG. 6, one image data is transmitted from the host device 300 at 50.00 msec, that is, at a refresh frequency of 20 Hz corresponding to the vertical synchronization signal. ,
The data is read from the frame memory 317 in the display device 301 three times at a period of 16.67 msec. That is, 50.00 msec, which is the time required to read image data having a refresh frequency of 20 Hz until the next image data is read out.
Is read out three times every 16.67 msec. Thus, image data (Rd_DATA0 to Rd_DATA3) whose refresh frequency has been tripled is created. That is, these image data (Rd_DATA)
0 to Rd_DATA3) are the video interface 3
The vertical synchronization signal (Rx_VS0 to Rd) obtained by increasing the frequency of the vertical synchronization signal (Tx_VS) from
_VS3) and output to the liquid crystal displays 305 to 308. Therefore, the image data is read at 60 Hz, which is three times the refresh frequency of the image data transmitted from the video interface 304.

The image data is, as shown in FIG.
For example, when an image is divided into four parts and displayed, the transmitted image data B is divided into four parts: an upper left image B0, an upper right image B1, a lower left image B2, and a lower right image B3. Is output. In addition, as a display method of the image data, one display unit may be divided and different image data may be displayed on each display unit. The image may be displayed on a display having a resolution.

In the present embodiment, as a method of synchronizing the writing and reading with respect to the frame memory, when reading the image data from the frame memory, the refresh frequency is set to three times the refresh frequency at the time of transmission. The refresh frequency at the time of displaying an image may be an integer multiple of the refresh frequency at the time of transmission, and is not particularly limited.

In this embodiment, as the display unit,
The liquid crystal display has been described.
Examples thereof include an RT display and a plasma display, and are not particularly limited.

As described above, the method of transferring image data according to the present embodiment includes the steps of transmitting image data lower than the refresh frequency displayed on the liquid crystal displays 305 to 308 from the host device 300 to the display device 301; A step of receiving the image data whose refresh frequency has been lowered by the display device 301 and temporarily storing the image data in the frame memory 317 in the display device 301; , The image data is read out by increasing the refresh frequency of the image data for each divided area, and the image data is displayed on each of the liquid crystal displays 305 to 308.

According to the above configuration, the frame memory 31
7, when the image data is read out, the image data is divided into a plurality of screen areas, the image data is read out by increasing the refresh frequency for each of the divided areas, and is displayed on each display, so that the data transfer clock frequency is low. Ultra-high-resolution image data can be displayed using a plurality of low-resolution displays.

Further, according to the above configuration, since the video interface 304 is of a digital type, the digital video signal generated by the graphics control circuit 302 can be transmitted to the display device 301 as it is digitally. Data does not deteriorate.

[0109]

According to the image data transmission method of the present invention, as described above, the first step of transmitting image data for which the refresh frequency is set from the host device to the display device, and the reception of the image of the refresh frequency. A second method of temporarily storing data in storage means provided in the display device
And a third step of increasing the refresh frequency of the image data and displaying the image on the display unit when reading the image data from the storage means.
This makes it possible to transmit image data while suppressing the data transfer clock frequency. Further, by increasing the refresh frequency of the image data received by the display device, an image without flicker can be displayed. Therefore, there is an effect that ultra-high-resolution image data, which is extremely difficult with the conventional configuration, can be transmitted.

Further, the conversion clock frequency for converting the image data into the analog RGB signal can be suppressed low, whereby the image data can be transmitted without burdening the D / A converter. Also play.

As described above, according to the image data transmission method of the present invention, in the third step, when the image data is read out from the storage means, the refresh frequency of the image data is set to n times (n = 2) that at the time of transmission. (The above natural number). Therefore, it is possible to prevent an image in one frame from being changed from the middle to the next image and displayed on the display.

As described above, according to the image data transmission method of the present invention, when reading out the image data from the storage means, the third step divides the image data into a plurality of screen areas, In this configuration, the refresh frequency of the image data is increased every time the image data is read out, and the image is displayed on each display unit. Therefore, there is an effect that ultra-high resolution image data can be transmitted to a plurality of screen areas.

As described above, according to the image display system of the present invention, the display device stores the image data received from the host device once, and stores the image data stored in the storage device. And a control unit for reading the read image data on the display unit at a refresh frequency higher than the refresh frequency at the time of transmission from the host device to the display device.
Therefore, the image data can be transmitted to the display device while keeping the data transfer clock frequency low. Further, by increasing the refresh frequency of the image data received by the display device, it is possible to provide an image display system capable of displaying an image without flicker. Further, the conversion clock frequency for converting the image data into the analog RGB signal can be suppressed low, so that the image data can be transmitted without placing a burden on the D / A converter. Therefore, there is also an effect that it is possible to provide an image display system capable of transmitting image data of very high resolution, which is extremely difficult with the conventional configuration.

As described above, in the image display system of the present invention, when reading out the image data from the storage means, the control means sets the refresh frequency of the image data to n times (n = 2 or more natural number) at the time of transmission. ). Therefore, it is possible to prevent an image in one frame from being changed from the middle to the next image and displayed on the display.

As described above, according to the image display system of the present invention, when reading out the image data from the storage means, the control means divides the image data into a plurality of screen areas,
The configuration is such that the image data is read out by increasing the refresh frequency of the image data for each divided area, and the image is displayed on each display unit. Therefore, it is possible to provide an image display system that can display an ultra-high-resolution image by using a plurality of low-resolution displays having a low data transfer clock frequency.

As described above, the image display system of the present invention has a configuration in which image data is transmitted from the host device to the display device by a digital video interface. Therefore, there is an effect that it is not necessary to temporarily convert the image data into an analog video signal, and an image display system in which the image data does not deteriorate can be provided.

As described above, the display device of the present invention has the storage means for temporarily storing the image data transmitted from the host device and the control for increasing the refresh frequency of the image data when reading the image data from the storage means. Means. Therefore, there is provided a display device capable of displaying an ultra-high-resolution image without flicker by increasing the refresh frequency of the image data when reading the image data stored from the storage means and displaying the image data on the display unit. It has the effect that it can be done.

As described above, in the display device of the present invention, the control means increases the refresh frequency to n times (n = 2 or more natural number) the transmission frequency when reading the image data from the storage means. This is the configuration that has been set. Therefore, there is an effect that it is possible to provide a display device that can prevent an image in one frame from being displayed in the middle of being changed to the next image.

As described above, in the display device of the present invention, when reading out the image data from the storage means, the control means divides the image data into a plurality of screen areas and outputs the image data to each of the divided areas. , The image data is read out by increasing the refresh frequency, and the images are displayed on the respective display units. Therefore, it is possible to provide a display device that can display an ultra-high-resolution image by using a plurality of low-resolution displays with low data transfer clock frequencies.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a schematic configuration of an image display system according to an embodiment of the present invention.

FIG. 2 is a plan view illustrating a configuration of a liquid crystal display control circuit of the image display system according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating timings of image data and a vertical synchronization signal of the image display system according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating timings of image data and a vertical synchronization signal of an image display system according to another embodiment of the present invention.

FIG. 5 is a plan view illustrating a schematic configuration of an image display system according to another embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating timings of image data and a vertical synchronization signal of an image display system according to another embodiment of the present invention.

FIG. 7 is an explanatory diagram when a screen of an image display system is divided and displayed according to another embodiment of the present invention.

FIG. 8 is a plan view showing a schematic configuration of a conventional image display system.

[Explanation of symbols]

100, 200, 300 Host device 101, 201, 301 Display device (display device) 104, 204, 304 Video interface 205, 305-308 Liquid crystal display (display unit) 106, 206, 309 Graphics controller 107, 207, 310 Graphics Memory 110, 210, 313 Video output connector 111, 211, 314 Video cable 112, 212, 315 Video input connector 203, 303 Liquid crystal display control circuit (control means) 214, 317 Frame memory (storage means) 215 Frame memory A ( Storage means) 216 Frame memory B (Storage means)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B069 AA01 BA03 BB04 BC02 LA02 LA12 5C082 AA02 BA12 BB01 BB22 BD01 BD02 CB01 DA65 MM02 MM04 MM07 MM10

Claims (10)

[Claims] A first step of transmitting image data for which a refresh frequency is set from a host device to a display device; and a step of storing the received image data of the refresh frequency in a storage means provided in the display device once. An image data transmission method, comprising: a second step of storing; and a third step of, when reading out the image data from the storage means, increasing the refresh frequency of the image data and displaying the image on a display unit. . 2. The method according to claim 1, wherein the third step increases the refresh frequency of the image data to n times (n = 2 or more natural number) when reading the image data from the storage means. 2. The image data transmission method according to 1. 3. The method according to claim 1, wherein, when reading the image data from the storage means, the image data is divided into a plurality of screen areas, and the refresh frequency of the image data is increased for each of the divided areas. And reading an image on each display unit.
The described image data transmission method. 4. An image data created by a host device,
In an image display system for transmitting to a display device at a predetermined refresh frequency and displaying the image on a display unit of the display device, the display device temporarily stores image data received from the host device; Control means for reading out the image data stored in the means at a refresh frequency higher than the refresh frequency at the time of transmission from the host device to the display device, and displaying the read image data on the display unit. An image display system characterized by the following. 5. The method according to claim 1, wherein the control means is configured to increase a refresh frequency of the image data to n times (n = 2 or more natural number) when reading the image data from the storage means. The image display system according to claim 4, wherein 6. When reading out image data from the storage means, the control means divides the image data into a plurality of screen areas and reads out the image data by increasing the refresh frequency of the image data for each of the divided areas. 6. The image display system according to claim 4, wherein an image is displayed on each display unit. 7. The image display system according to claim 4, wherein transmission of the image data from the host device to the display device is performed by a digital video interface. 8. A storage device for temporarily storing image data transmitted from a host device, and control means for increasing a refresh frequency of the image data when reading the image data from the storage device. Display device. 9. The apparatus according to claim 1, wherein said control means is configured to increase the refresh frequency to n times (n = 2 or more natural number) the transmission frequency when reading the image data from said storage means. Item 10. The display device according to Item 8. 10. When reading out image data from the storage means, the control means divides the image data into a plurality of screen areas, and reads out the image data by increasing the refresh frequency of the image data for each of the divided areas. 10. The display device according to claim 8, wherein an image is displayed on each display unit.