JPH08335057A - Led display device - Google Patents

Abstract

PURPOSE: To provide a LED display device which causes no unnatural difference in level even when laterally scrolled. CONSTITUTION: This device has a personal computer having an image reader or CRT display device, a memory circuit 1 having a memory capacity corresponding to the picture element number of the CRT display device, a data writing part 7 for receiving RGB analog signal and synchronous signal and writing a gradation data KK into the memory circuit 1, a data reading part 6 formed out of a plurality of reading circuits 6-i for converting the gradation data into PWM wave, and reading the gradation data in parallel for every fixed memory block, and a LED display panel 2 formed out of the combination of a plurality of delay circuit 8-i for supplying start pulses delayed by a fixed time to each reading circuit with a number of LED lamps, and receiving the PWM wave from each reading circuit to emit a light form each LED lamp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED display device using a plurality of LED lamps, and in particular, an LED which does not cause a display shift even when the screen is scrolled horizontally.
Regarding display device.

[0002]

2. Description of the Related Art CRT display devices such as NTSC TVs and CRT display devices for personal computers have widely used cathode ray tubes in the world of image display today, and their image signal system has become a de facto standard. Various standard devices and software for personal computers that comply with this standard are provided. By using these, you can easily import still images and moving images to your computer, and capture image information as appropriate. It becomes possible to edit.
Therefore, even when a moving image or a still image is displayed on the LED display panel, an image is first created on the personal computer and is sent to the LED display panel to improve the efficiency of the system. FIG. 5 illustrates an example of an LED display device that creates an image to be displayed on the LED display panel 22 by utilizing the personal computer 20. This L
The ED display device has a C having pixels of 480 vertical × 640 horizontal.
A personal computer 20 having an RT display section 20a, a memory section 21 for storing the gradation data D _K for the pixels, and an RGB3
The display panel 22 is composed of 480 (vertical) × 640 (horizontal) LED lamps that emit light with a luminance corresponding to each gradation data D _K for the primary color. An image of 30 frames per second is displayed on the CRT display unit 20a (non-inte
(rlace method) 480 scanning lines forming one frame are sequentially scanned from the upper right to the lower left over a time period of 1/30 second (see FIG. 6A). Therefore, the writing circuit 23, in accordance with the screen scanning on the CRT display unit 20a, 480 × 640 for each RGB color in 1/30 seconds.
The individual gradation data D _K is written in the memory circuit 21. The read circuit 24 is a circuit for reading the gradation data D _K of the memory circuit 21 and driving the LED lamp of the display panel 22, but if the same operation as the writing of the gradation data D _K is performed, the LED lamp 1 The lighting time for each piece is insufficient, and the predetermined brightness cannot be obtained on the display panel 22. Therefore, the display panel 22 is subdivided into 30 display blocks (# 1 to # 30), and the read circuit 24 is provided for each display block to drive each display block independently. That is, each display block (#
1 to # 30) is 16 vertical by 640 horizontal for each RGB color.
The read circuit 24 takes 16/640 grayscale data D _K for the same 1/30 second as the write circuit 23, and the read circuit 24 reads the corresponding grayscale data D _K. Are being driven (see FIG. 6B).
The writing circuit 23 and the reading circuit 24 start operating in synchronization with the frame synchronization signal S _V output from the personal computer 20.

[0003]

However, the conventional LED display device shown in FIG. 5 has a problem that an unnatural step is formed on a vertical line when the screen is scrolled in the left-right direction. FIG. 7 illustrates this state, and although the vertical line BAR is a straight line BAR that is straight as a still image, scrolling to the left causes a step to occur in places. . The present invention has been made in view of this problem, and an LED that does not cause an unnatural step even when scrolled in the left-right direction
An object is to provide a display device.

[0004]

The cause of the display shift as shown in FIG. 7 is considered to be that the writing (rewriting) speed to the memory circuit 21 and the reading speed from the memory circuit 21 do not match. That is, the memory circuit 21
The rewriting speed is faster than the reading speed because the grayscale data D _K is read out for each display block over the same 1/30 second while the rewriting is performed in a time of / 30 seconds. This means that the gradation data is rewritten during the read operation.
FIG. 8 illustrates the relationship between the writing speed and the reading speed. In FIG. 8A, it takes 1/30 seconds to display the gradation from the first row to the 480th row of the display unit 20a. 8B shows that the data is rewritten, and FIG. 8B shows 16 rows of the first display block of the display panel 22, 16 rows of the second display block, ... And 1 of the 30th display block.
It is shown that the grayscale data for 6 rows are separately read in 1/30 seconds. In the following description, for convenience of description, the time required to write or read the gradation data for each row will be represented by H (480H = 1).
/ 30 seconds, H = 1/14400 seconds). The grayscale data is read at a time of 480H for each display block, while the rewriting of each display block is 1 for each.
Since it is completed in 6 hours, for example, for the tenth display block, the equation 16Hi = 480H (i-9) holds, and the display block i = 270 / 29≈9.3.
At the position of 1, the rewriting process will catch up.
Display block i = 9.31 means around the 4.97th line of the 10th display block (0.31
X16 = 4.97), the 10th display block displays old grayscale data for the 1st to 4.97th lines, and for the 4.97th to 16th lines. This means that the rewritten new gradation data is being displayed, and in the end, when the screen scrolls to the left, the step shown in the figure occurs. Therefore, in the display device according to the present invention, in order to prevent the display shift, two storage units are provided, or
The display timing of each display block is delayed little by little. That is, the LED display device according to claim 1 is provided with an image reading device and an image display device, and is used for editing processing of a still image or a moving image that is arbitrarily captured, or CG (com
putergraphics) An image creating unit that creates an appropriate image by an image creating process and the like, first and second storage units (1A, 1B) having a data storage capacity corresponding to the number of pixels of the image display device, It receives a video signal and a sync signal supplied to the image display device, converts the video signal into digital gradation data, and alternately selects one of the storage units (1A, 1B) based on the sync signal. Then, the data writing unit (3, 4) for writing the gradation data into the selected storage unit
Then, based on the synchronization signal, the storage unit that is not writing data is selected, the grayscale data in the selected storage unit is read in parallel for each fixed memory lock, and this is pulsed. Data reading unit for converting to waves (5,6)
And a large number of LED lamps combined, each LE
The D lamp includes an LED display panel (2) which emits light upon receiving the pulse wave. Since the first and second storage units are used by being switched, the gradation data being read is not rewritten, and there is no fear of causing an unnatural step on the display panel. Further, the LED display device according to claim 2 is provided with an image reading device and an image display device, and creates an appropriate image by an editing process of a still image or a moving image that is arbitrarily captured, or a CG image creating process. An image creating unit, a storage unit (1) having a data storage capacity corresponding to the number of pixels of the image display device, a video signal and a synchronization signal supplied to the image display device, and the video signal A data writing unit (7) for converting into gradation data and writing it in the storage unit; and a plurality of units for starting the operation based on a start signal and reading the gradation data stored in the storage unit and converting it into a pulse wave. A data reading unit including a plurality of reading circuits, and the plurality of reading circuits read the gradation data in parallel for each fixed storage block.
(6) an operation start command section (8) which operates by receiving the synchronization signal and supplies a start signal delayed by a fixed time to each of the plurality of read circuits, and a large number of LEs.
An LED formed by combining D lamps, each LED lamp emitting light in response to pulse waves from the plurality of reading circuits.
And a display panel (2).

[0005]

The present invention will be described in more detail based on the following examples. [Embodiment 1] FIG. 1 shows an LED having a display shift prevention function.
1 illustrates an example of a display device. This LED display device is a personal computer (not shown) equipped with a CRT display unit consisting of 480 × 640 pixels and 480 × 64 pixels, respectively.
It is composed of first and second memory circuits 1A and 1B having a storage capacity of 0 pixels and a display panel 2 including an LED lamp of 480 × 640 pixels. The display panel 2 includes display blocks 1 to 30 (# 1 to # 1).
30), each display block is 16 × 6
It consists of an LED lamp for 40 pixels. Similarly,
Each of the first and second memory circuits 1A and 1B corresponds to the display block (# 1 to # 30) of the display panel 2 and has three units.
It is divided into 0 memory blocks.

By the operations of the writing circuit 3 and the first switching circuit 4, the gradation data D _{K for} 480 × 640 pixels is written in the memory circuits 1A and 1B.
That is, the writing circuit 3 receives the RGB analog signal from the personal computer, converts it into 8-bit gradation data D _K , and outputs it to the first switching circuit 4. Then, the first switching circuit 4 outputs the frame synchronization signal S _V output from the personal computer.
The operation state is switched each time it receives an odd-numbered frame synchronization signal S _V , and the gray-scale data D _K is supplied to the first memory circuit 1A when an odd-numbered frame synchronization signal S _V is received.
_{When V} is received, the gradation data D _K is supplied to the second memory circuit 1B. By this operation, the first memory circuit 1A has the first frame, the third frame, the CRT display portion of the personal computer,
The image information of ... Is stored, and the second memory circuit 1B stores
The image information of the second frame, the fourth frame, ... Is stored. Note that the writing of the gradation data D _K
For each of the memory circuits 1A and 1B, the time-sequential processing is performed from the upper left to the lower right of one frame image in 1/30 seconds.

Grayscale data D from the memory circuits 1A and 1B
The reading of _K is performed by the second switching circuit 5 and the reading unit 6. The second switching circuit 5 receives gradation data of each memory block of the first and second memory circuits 1A and 1B,
Every time the frame synchronization signal S _V is received, only the grayscale data of one of the memory circuits 1A and 1B is supplied to the reading section 6. The operation of the second switching circuit 5 is the reverse of that of the first switching circuit 4. When the odd-numbered frame synchronization signal S _V is received, the grayscale data of the second memory circuit 1B is output, while the even-numbered frame synchronization signal S _V is output. _When receiving _V , the first memory circuit 1
The gradation data of A is output. With the above operation, when the writing process is being performed on the first memory 1A, the gradation data of the second memory 1B is output, and conversely, the writing process is being performed on the second memory 1B. Sometimes, the gradation data of the first memory 1A will be output. The readout unit 6 is composed of 30 readout circuits 6 _-i corresponding to the number of memory blocks and display blocks, and converts the gradation data D _K output by the second switching circuit 5 into a PWM wave or the like to display the panel. Supply to 2. This read circuit 6 _-i is
Starts operation in synchronization with the frame synchronization signal S _V
Although the lamp is driven, unlike the conventional device, since the grayscale data is not rewritten while reading the grayscale data from the memory circuit, it is unnatural even when displaying a screen that scrolls left and right. There is no danger of a large step.

[Second Embodiment] FIG. 2 illustrates another embodiment of an LED display device having a display shift prevention function. This LED display device is a personal computer (not shown) equipped with a CRT display device and an image reading device, and a 480 ×
Memory circuit 1 having a storage capacity of 640 pixels and 4
A display panel 2 including an LED lamp for 80 × 640 pixels, a writing section 7 for converting an RGB analog signal output from a personal computer into 8-bit gradation data D _K and storing it in the memory circuit 1, and a memory circuit 1. Reading unit 6 including 30 reading circuits 6 _-i for reading the grayscale data D _K of
And a delay circuit 8- _i for supplying a separate start signal ST to each read circuit 6- _i . The writing unit 7 is composed of a timing circuit 7a and an A / D converter 7b. The timing circuit 7a receives the frame synchronization signal S _V and the horizontal synchronization signal S _H from the personal computer, and receives the address data AD _ij and the dot. The clock S _D is output to the memory circuit 1. Further, the A / D converter 7b receives the RGB analog signal from the personal computer and outputs the dot clock S _D
And is converted into 8-bit gradation data D _K in synchronism with. The dot clock S _D is the gradation data D _K for the memory circuit 1.
Is a signal for determining the write timing (see FIG. 3), and the write processing of the grayscale data D _K of 480 × 640 bytes is performed for each RGB color during 1/30 second (= 480H).

The read circuit 6- _i starts its operation upon receiving the start pulse ST, and at 1/30 second (= 480H), it reads from each memory block of the memory circuit 1 for each floor of 16 × 640 bytes for each color of RGB. Read the key data D _K. Then, the read gradation data D _K is converted into a PWM wave or the like and then supplied to the corresponding LED lamp, and each LED lamp emits light with a luminance corresponding to the gradation data D _K. The delay circuit 8- _i is a circuit for receiving the horizontal synchronizing signal S _H and the frame synchronizing signal S _V and outputting a start pulse ST, and the horizontal synchronizing signal S _{H is} 16 (= 16 _H ) frame synchronizing signal S. Delay _V. As shown in FIG. 2, since 30 delay circuits 8 _-i are connected in series, the first delay circuit 8 _-1 is connected to the frame synchronization signal S _V.
The start pulse ST delayed by 16H from
The second delay circuit 8 _-2 outputs the start pulse ST delayed by 16H, and similarly, the start pulse ST delayed by 16H is output.

The writing section 7 requires 16 hours,
Grayscale data (16 × 640 bytes) for one display block is written, while each read circuit 6 _-i is 16H
Grayscale data of each display block (16 ×
640 bytes) is read out, so the gradation data after the writing is completed is read out.
It is always driven based on the latest gradation data. Therefore, even if a screen that scrolls in the left-right direction is displayed, an unnatural step unlike the conventional device does not occur. Note that FIG. 4 schematically shows the relationship between the writing operation WR of gradation data to the memory circuit 1 and the reading operation RD from the memory circuit 1,
This indicates that the read operation RD is performed on the gradation data after the rewriting is completed.

Although the first and second embodiments have been described above, the number of pixels (= 480 × 640), the number of display blocks (= 30), the number of bits of gradation data (= 8), and the like are used for convenience of explanation. It is needless to say that the present invention is not limited to these only by specifying numerical values. Further, the number of pixels of the display panel 2 may be different from the number of pixels of the CRT display device, or the grayscale data may have a 1-bit length so that only a monochrome pattern is displayed on the display panel 2.

[0012]

As described above, the LE according to the present invention
In the D display device, since two storage units are provided or the display timing of each display block is delayed little by little, an unnatural step is generated even if a screen scrolling in the left and right direction is displayed. There is no such thing.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of another embodiment of the present invention.

FIG. 3 is a timing chart explaining the operation content of the apparatus of FIG.

FIG. 4 illustrates a relationship between a writing process and a reading process.

FIG. 5 is a block diagram of a conventional LED display device.

FIG. 6 is a diagram for explaining a scanning method of a CRT display device and an LED display panel in comparison.

FIG. 7 illustrates a problem of a conventional LED display device.

FIG. 8 is a diagram illustrating the cause of the phenomenon of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 memory circuit (storage part) 1A 1st memory circuit (1st storage part) 1B 2nd memory circuit (2nd storage part) 2 LED display panel 3 writing circuit 4 1st switching circuit 5 2nd switching circuit 6 reading part 6- _i read circuit 7 write section 8- _i delay circuit RGB RGB analog signal S _V , S _H sync signal D _K gradation data

Claims (3)

[Claims] 1. An image creating unit that includes an image reading device and an image display device, and creates an appropriate image by an editing process of a still image or a moving image that is arbitrarily taken in, a creating process of a CG image, or the like. The first and second storage units (1A, 1B) having a data storage capacity corresponding to the number of pixels of the image display device, and a video signal and a synchronization signal supplied to the image display device, A data writing unit (3) that converts the digital grayscale data and alternately selects one of the storage units (1A, 1B) based on the synchronization signal, and writes the grayscale data to the selected storage unit. , 4), and based on the synchronization signal, selects the storage unit that is not writing data, and reads the grayscale data in the selected storage unit in parallel for each fixed memory lock,
An LED display panel comprising a combination of a data reading section (5, 6) for converting this into a pulse wave and a large number of LED lamps, each LED lamp receiving the pulse wave and emitting light.
(2) An LED display device comprising: 2. An image creating unit that includes an image reading device and an image display device, and creates an appropriate image by an editing process of a still image or a moving image that has been arbitrarily captured, a CG image creating process, or the like. A storage unit (1) having a data storage capacity corresponding to the number of pixels of the image display device, receiving a video signal and a synchronization signal supplied to the image display device, converting the video signal into gradation data, and A data writing section (7) to be written in the storage section, and a plurality of read circuits that start operation based on a start signal and read the gradation data stored in the storage section and convert it into pulse waves, A data reading unit (6) configured to read the gradation data in parallel for each fixed storage block by the plurality of reading circuits; and to operate by receiving the synchronization signal. Then, the operation start command section (8) for supplying a start signal delayed by a fixed time and a large number of LED lamps are combined, and each LED lamp receives a pulse wave from the plurality of reading circuits. An LED display device comprising: an LED display panel (2) that emits light. 3. The LED display device according to claim 1, wherein the image display device is a CRT display device, and a personal computer is used in the image creating unit.