JP2902978B2 - LED display device and image display method thereof - Google Patents

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 more particularly, to an LED device which does not cause a display shift even when the screen is scrolled in the right and left directions.
It relates to a display device.

[0002]

2. Description of the Related Art In today's video display world, such as CRT display devices for personal computers, including NTSC TVs, CRTs are widely used, and the video signal system has been established as a de facto standard. Various standard equipment and software for personal computers are provided according to this standard, and by using these, still images and moving images can be easily imported to a personal computer. It becomes possible to edit.
Therefore, even when displaying a moving image or a still image on the LED display panel, an image is first created on a personal computer, and the created image is transmitted 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 using the personal computer 20. This L
The ED display device has a C pixel having 480 × 640 pixels.
A personal computer 20 including the RT display unit 20a, a memory unit 21 for storing the gradation data D _K of the pixel, RGB three
It is composed of a display panel 22 consisting of vertical 480 × horizontal 640 LED lamp emits light at luminance corresponding to the gradation data D _K for primary colors. The CRT display unit 20a displays an image of 30 frames per second (non-inte
(rlace method) The 480 scanning lines forming one frame are sequentially scanned from the upper right to the lower left over 1/30 second (see FIG. 6A). Therefore, the writing circuit 23 performs 480 × 640 for each of the RGB colors within 1/30 second in accordance with the screen scanning on the CRT display section 20a.
The number of gray-scale data D _K are to be written into the memory circuit 21. Read circuit 24 is a circuit for driving the LED lamps of the display panel 22 reads the gray-scale data D _K of the memory circuit 21, than to the same operation as the write gray scale data D _K is the LED lamp 1 Since the lighting time per unit is insufficient, a 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 a readout circuit 24 is provided for each display block to drive each display block independently. That is, each display block (#
1 to # 30) are 16 × 640 for each color of RGB.
Consists of a number of LED lamps, the read circuit 24, over the same 1/30 second time and write circuit 23 reads each 16 × 640 pieces of the gradation data D _K, corresponding display block (See FIG. 6B).
Incidentally, the write circuit 23 and read circuit 24 starts operating in synchronism with the frame synchronizing signal S _V outputted from the personal computer 20.

[0003]

However, the conventional LED display device shown in FIG. 5 has a problem that when the screen is scrolled left and right, an unnatural step occurs in the vertical line. FIG. 7 illustrates this state. In spite of a single vertical line BAR as a still image, when this is scrolled to the left, a step occurs in some places. . The present invention has been made in view of this problem, and does not cause an unnatural step even when scrolling in the left-right direction.
It is an object 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, when the memory circuit 21
/ Against 30 seconds of being rewritten in time, over the same 1/30 second time, since the grayscale data D _K is read for each display block is faster rewriting speed than the reading speed That is, the grayscale data is rewritten during the read operation.
FIG. 8 illustrates the relationship between the writing speed and the reading speed. FIG. 8A illustrates the gradation from the first line to the 480th line of the display unit 20a in 1/30 second. 8B shows that the data is rewritten. 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.
This indicates that the gradation data for six rows is separately read in 1/30 seconds. In the following description, for the sake of convenience, the time required for writing and reading the gradation data for each row is represented by H (480H = 1).
/ 30 sec, H = 1/14400 sec). The readout of the gradation data is performed at the time of 480H in each display block, whereas the rewrite of each display block is performed by 1 time.
Since it is completed in the time of 6H, for example, for the tenth display block, the equation of 16Hi = 480H (i-9) is satisfied, and the display block i = 270/29 ≒ 9.3.
The rewriting process catches up at position 1.
Since the display block i = 9.31 means around the 4.97th line of the tenth display block, (0.31
× 16 = 4.97), the tenth display block displays the old gradation data for the first to 4.97th lines, and displays the old gradation data for the 4.97 to 16th lines. This means that the rewritten new gradation data is displayed, and eventually, when the screen is scrolled to the left, the step shown in the drawing occurs. Therefore, in the display device according to the present invention, the display timing of each display block is gradually delayed in order to prevent a display shift. That, LED display device according to claim 1 is provided with a picture image read or an image display apparatus, editing processing of still images and videos captured arbitrarily or the like creation process of CG images, an appropriate image An image creation unit to be created, a storage unit (1) having a minimum necessary 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 (7) for converting the video signal into grayscale data and writing the grayscale data into the storage unit; and starting an operation based on the start signal to read out the grayscale data stored in the storage unit and pulse A data readout unit (6) comprising a plurality of readout circuits for converting the data into waves, wherein the plurality of readout circuits read out the gradation data in parallel for each predetermined storage block; An operation start command unit (8) that operates in response to a synchronization signal and supplies a start signal delayed by a predetermined time to each of the plurality of read circuits, and a plurality of LED lamps. L that each LED lamp emits light upon receiving a pulse wave from the readout circuits.
An ED display panel (2) is provided. Ma
In addition, the image display method of the LED display device according to claim 3 comprises:
Converts the video signal created by the image creation unit to gradation data
A storage unit having a storage capacity for pixels of the image creation unit.
And the gradation data written in the storage unit.
By N read circuits for each fixed storage block.
Read in parallel and read the read gradation data with pulse wave
To the corresponding N display blocks.
To output the video signal created by the image creation unit to the N
Is displayed on an LED display device with a number of display blocks
A video display method as shown in FIG.
Each has its own gradation data in its own memory block.
The reading process starts as soon as the data starts to be written.
To start. Note that "Grayscale data is written
Start the readout process as soon as the
Means the operation contents shown in FIG.

[0005]

( Reference example )

1 state, and are not illustrated one example of a LED display device including a display displacement prevention function, listed as a reference example of the present invention
Things . This LED display device includes a personal computer (not shown) having a CRT display unit composed of 480 × 640 pixels, first and second memory circuits 1A and 1B each having a storage capacity of 480 × 640 pixels. , 480 ×
The display panel 2 includes an LED lamp for 640 pixels. The display panel 2 includes first to thirtieth display panels.
The display blocks are subdivided into display blocks (# 1 to # 30), and each display block is configured by LED lamps for 16 × 640 pixels. Similarly, the first and second memory circuits 1A and 1B are connected to the display blocks (# 1 to # 1) of the display panel 2.
# 30), each is divided into 30 memory blocks.

[0006] Memory circuits 1A, and 1B are, by a write circuit 3 operates the first switching circuit 4, so that the gray-scale data D _K of pixels 480 × 640 is written.
That is, the write circuit 3 receives the RGB analog signal from the personal computer, and outputs this to first switching circuit 4 converts the gradation data D _K of 8bit. Then, the first switching circuit 4 outputs the frame synchronization signal S _V output from the personal computer.
Switching an operating state for each receive, while supplying the gray-scale data D _K to the odd frame synchronizing signal when receiving the S _V first memory circuit 1A, the even-numbered frame synchronizing signal S
Upon receiving _V , the grayscale data _DK is supplied to the second memory circuit 1B. By this operation, the first frame, the third frame, and the third frame of the CRT display unit of the personal computer are stored in the first memory circuit 1A.
Are stored in the second memory circuit 1B.
The image information of the second frame, the fourth frame,... Is stored. Incidentally, the writing of tone data D _K,
For each of the memory circuits 1A and 1B, the processing is performed in time sequence from the upper left to the lower right of the image of one frame during 1/30 second.

The 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 the gradation data of each memory block of the first and second memory circuits 1A and 1B,
Each receiving a frame sync signal S _V, one of the memory circuit 1A, and supplies only the read section 6 of the grayscale data 1B. The operation of the second switching circuit 5 is the reverse of that of the first switching circuit 4. When receiving the odd-numbered frame synchronization signal S _V , the second memory circuit 1B outputs the gradation data, while the even-numbered frame synchronization signal S _V is output. _When receiving _V , the first memory circuit 1
A gradation data is output. By 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. At times, the gradation data of the first memory 1A is output. Reading unit 6, corresponding to the number of memory blocks and the display blocks consists of 30 pieces of read circuit 6 _-i, the display panel by converting the gradation data D _K of the second switching circuit 5 is output to such PWM wave Feed to 2. This read circuit 6 _-i
LED starts operating in synchronism with the frame synchronizing signal S _V
Although the lamp is driven, the gradation data is not rewritten when reading the gradation data from the memory circuit as in the conventional device, so it is unnatural even when displaying a screen that scrolls horizontally. There is no possibility that a large step will occur.

[0008] First Embodiment FIG. 2 is an illustration of the actual <br/>施例the LED display device having a display displacement prevention function. This LED display device is C
A personal computer (not shown) having an RT display device, an image reading device, etc., a memory circuit 1 having a storage capacity of 480 × 640 pixels, and a display panel 2 having LED lamps of 480 × 640 pixels. , PC output RG
B and the analog signal is converted to 8-bit grayscale data D _K writing unit 7 to be stored in the memory circuit 1, 30 of the read circuit 6 _-i reading the grayscale data D _K of the memory circuits 1
And a delay circuit 8- _i for supplying a separate start signal ST to each of the read circuits 6- _i . The writing unit 7 includes a timing circuit 7a
And an A / D converter 7b. The timing circuit 7a includes a frame synchronization signal _Sv and a horizontal synchronization signal _SH.
From the personal computer, and outputs the address data AD _ij and the dot clock _SD to the memory circuit 1. Also, A
/ D converter 7b receives the RGB analog signal from the personal computer, in synchronization with the dot clock _{S D,} is converted to 8-bit grayscale data _{D K.} Dot clock _{S D} is a signal for determining the timing for writing grayscale data _{D K} to the memory circuit 1 (see FIG. 3), 1/30 seconds (= 480
During H), the writing process of the gradation data _Dk of 480 × 640 bytes is performed for each of the RGB colors.

The readout circuit 6- _i starts operation in response to the start pulse ST, and in 1/30 seconds (= 480H), 16 × 640 bytes of RGB colors are read from each memory block of the memory circuit 1. It reads the control data D _K. Then, the tone data D _K read, after being converted into such PWM wave is supplied to the relevant LED lamp, emits light at a luminance each LED lamps corresponding to the grayscale data D _K. The delay circuit 8- _i is a circuit which receives the horizontal synchronizing signal S _H and the frame synchronizing signal S _V and outputs a start pulse ST. The frame synchronizing signal S is equivalent to 16 horizontal synchronizing signals S _H (= 16H). Delay _V. As shown in FIG. 2, since the 30 delay circuits 8- _i are connected in series, the first delay circuit _8-1 provides the frame synchronization signal _SV.
And outputs a start pulse ST delayed by 16H from the second
Th delay circuit _8-2 outputs a start pulse ST that further 16H delay, likewise, so that the start pulse ST that is delayed by 16H is output below.

The writing unit 7 requires 16H time,
While the grayscale data (16 × 640 bytes) for one display block is written, each of the read circuits 6 _-i has 16H
The gradation data (16 ×
640 bytes), the gray scale data after the writing is completed is read, and the display panel 2
The drive is always performed based on the latest gradation data. Therefore, even if a screen that scrolls in the left-right direction is displayed, an unnatural level difference unlike the conventional device does not occur. FIG. 4 schematically illustrates the relationship between the write operation WR of the grayscale data to the memory circuit 1 and the read operation RD from the memory circuit 1.
This indicates that the read operation RD is being performed on the gradation data after the completion of the rewriting.

[0011] While there has been described about the Reference Example Example, the number of pixels (= 480 × 640) and display the number of blocks (=
30) and the number of bits of the grayscale data (= 8) are merely numerical values for convenience of explanation, and the present invention is not limited to these. 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 be set to 1 bit length so that only the monochrome pattern is displayed on the display panel 2.

[0012]

As described above, the LE according to the present invention is used.
In D display apparatus, since the delay the display timing of each display block gradually, even to display the screen as scrolling in the horizontal direction, does not unnatural step is formed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a reference example of the present invention.

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

FIG. 3 is a timing chart for explaining the operation of the apparatus shown in FIG. 2;

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. 7;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 memory circuit (storage section) 1A first memory circuit (first storage section) 1B second memory circuit (second storage section) 2 LED display panel 3 writing circuit 4 first switching circuit 5 second switching circuit 6 reading section 6 _-i read circuit 7 write unit 8 _-i delay circuit RGB RGB analog signal S _V, S _H sync signal D _K gradation data

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-55887 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G09G 3/00-3/38

Claims (3)

(57) [Claims] An image creation unit that includes an image reading device and an image display device, and that creates an appropriate image by performing a process of editing a still image or a moving image arbitrarily captured or a process of creating a CG image; A storage unit (1) having a minimum necessary 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 (7) for converting the data into grayscale data and writing the grayscale data into the storage unit; and starting an operation based on the start signal to read out the grayscale data stored in the storage unit and convert it into a pulse wave A data reading unit (6) configured to read out the gradation data in parallel for each predetermined storage block by the plurality of reading circuits; An operation start command section (8) for supplying a start signal delayed by a predetermined time to each of the plurality of read circuits; and a plurality of LED lamps, wherein a pulse from the plurality of read circuits is provided. An LED display device comprising: an LED display panel (2) in which each LED lamp emits light in response to a wave. 2. The LED display device according to claim 1, wherein the image display device is a CRT display device, and a personal computer is used for the image creation unit. 3. A video signal created by an image creating section is converted into a gradation signal.
Data, and the storage capacity for the pixels of the image creation unit is
While writing the grayscale data written in the storage unit into N readout cycles.
Read in parallel for each fixed storage block depending on the path
The read gradation data is converted into a pulse wave, and the
Output to each of the N display blocks, and the video signal created by the image creation unit is displayed on the N display blocks.
Image displayed on LED display device with blocks
An image display method, wherein each of the N readout circuits is in charge of itself.
Fit to the grayscale data starts is written to the memory block
And start the reading process.
Image display method of an LED display device.