JP3679657B2 - Image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image display device, and more particularly to a light-emitting device including a display unit in which a plurality of light-emitting diodes are arranged in a matrix.
[0002]
[Prior art]
Today, high-intensity light emitting diodes of 1000 mcd or more have been developed for each of RGB, and large LED displays have been manufactured. This LED display has features such as being lightweight, thin and low in power consumption, and the demand is rapidly increasing as a large display that can be used outdoors.
Actually, a large LED display is configured by combining a plurality of LED units according to the installation location, and the LED unit is configured by arranging RGB light emitting diodes in a dot matrix form on a substrate. The
[0003]
Since this LED display has a relatively large variation in, for example, the brightness of the LED elements, the LED display is usually configured to display a high-quality image using image data corrected for each LED element.
Specifically, the control circuit has a ROM that is a correction data storage unit that stores correction data corresponding to each LED element, and uses image data corrected based on the correction data stored in the ROM. The control circuit is configured to display.
[0004]
[Problems to be solved by the invention]
However, in the conventional LED display device, the correction data cannot be rewritten because the correction data is stored in the ROM, and a storage device that can be rewritten separately from the ROM when another correction data is required. There was a problem that it was necessary to provide.
[0005]
SUMMARY An advantage of some aspects of the invention is that it provides an image display device that can store a plurality of correction data in a single correction data storage unit.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an image display device according to the present invention is an image display device for collecting a plurality of LED units to constitute an LED display,
The image display device includes a display unit in which light emitting diodes are arranged in a matrix of m rows and n columns, a correction data storage unit that stores correction data corresponding to each light emitting diode, and input image data as described above. A control drive circuit that corrects based on the correction data and displays the image on the display unit using the corrected image data ,
The correction data storage unit is comprised advance first region in which the first correction data is stored and write is prohibited, the one storage element and a writable second region, constituting the LED display When replacing some of the LED units, the correction data of the LED unit to be replaced is written in the second area .
With this configuration, the image display device according to the present invention can protect the first correction data stored in the first area from being erased, and can use the writable second area to make the first correction. Second correction data different from the correction data can be stored, and image data can be corrected by selecting either the first correction data or the second correction data as necessary. In addition, a large display that collects a plurality of the units and displays the entire image can be easily configured.
[0007]
In the image display device according to the present invention, the correction data storage unit can be configured using a nonvolatile memory capable of electrically erasing and writing data.
[0008]
Further, in the image display device according to the present invention, communication control for further setting the second correction data different from the first correction data to the second area and prohibiting the writing of the first area. You may comprise and comprise a part.
[0009]
Furthermore, in the image display device according to the present invention, it is preferable that the writable second area can be set to be write-inhibited in order to protect the written correction data.
[0010]
Still further, in the image display device according to the present invention, the correction data storage unit stores correction data of the light emitting diode so that the address and each light emitting diode correspond to each other, and the first and second regions are stored. It is preferable to identify by the upper bits of the address.
In this way, the lower address bits can be set to the same read address.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an image display apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram conceptually showing the overall configuration of an image display apparatus according to an embodiment of the present invention.
In the image display device of the present embodiment, the image data input unit 27 inputs input image data to the control unit 25.
The correction data storage unit 26 includes, for example, an EEPROM (nonvolatile memory capable of electrically erasing and writing data) having a first area and a second area, and is a data for correcting the luminance variation of each pixel element. Etc. are stored in the first area, and the second correction data are stored in the second area.
In the present embodiment, data for correcting luminance variation is described as an example of correction data. However, the present invention is not limited to this.
[0012]
The image data correction unit 24 corresponds to each image data corresponding to each pixel input via the image data input unit 27 and the control unit 25, and corresponds to each pixel input via the control unit 25 and the buffer memory 30. The correction is performed based on the first or second correction data, and is input to the horizontal drive unit 23 as gradation data corresponding to each pixel.
In the image display device according to the present embodiment, the buffer memory 30 includes memories 30 (1) to (n) respectively corresponding to the columns 1 to n.
The horizontal drive unit 23 includes n memories provided corresponding to each of the n columns, and each gradation data input corresponding to each pixel is provided corresponding to the column to which the pixel belongs. The current line corresponding to the gradation width corresponding to the gradation data stored in the memory and stored in the memory in response to the control signal of the control unit 25 is set to the driving state.
[0013]
The vertical drive unit 22 includes m switch circuits respectively connected to the m common source lines, and connects the designated common source line to the current source in accordance with a control signal from the control unit 25. .
As described above, the control unit 25 reads the first or second correction data from the correction data storage unit 26 and stores the first or second correction data in the buffer memory 30, and data input / output timing of the buffer memory 30 or the image data correction unit 24. In addition to the above control, each pixel of the display unit is sequentially turned on by controlling connection switching between the common line and the current source in the vertical driving unit 22 and switching control of the current line driving state in the horizontal driving unit 23. The image corresponding to the input image data is displayed on the display unit.
[0014]
Here, in particular, the image display apparatus of the present embodiment has the following characteristics.
(1) The correction data storage unit 26 includes a first area in which first correction data corresponding to each pixel is stored in advance and a writable second area.
(2) The communication control unit 28 further sets the image display device so that the second correction data different from the first correction data can be written in the second area, and writing in the first area is prohibited. It has.
(3) The control unit 25 can select and store either the first correction data stored in the first area or the second correction data stored in the second area in the buffer memory 30.
[0015]
With such a feature, in the image display device according to the present embodiment, the first correction data stored in the first area can be protected from being erased, and the first area can be protected using the writable second area. Second correction data different from the correction data can be stored, and image data can be corrected by selecting either the first correction data or the second correction data as necessary.
[0016]
Specific example (2BANK correction control circuit for luminance correction data: FIG. 2)
Hereinafter, a specific example of the image display apparatus according to the present invention will be described with reference to FIG.
The image display device of this specific example includes an LED dot matrix display unit 1 as a display unit, a common driver 4 as a vertical drive unit, an EEPROM 7 as a correction data storage unit, a correction circuit 8b of an LED driver IC 2 as an image data correction unit, and a horizontal drive unit. As a drive unit 8a of the LED driver IC2, a command control unit 5 and a control unit 6 as a control unit, a serial communication interface 3 as a communication control unit, and a shift register 10 and a register 9 of the LED driver 2 as a buffer memory.
The command control unit 5 inputs a common line selection control signal LINE ADR to the common driver 4, and inputs a lighting control signal BLANK to each drive unit 8a and the correction circuit 8b.
[0017]
In this specific example, the EEPROM 7 includes, for example, BANK 0 into which correction data is written at the time of shipment from the factory and BANK 1 into which the user can write correction data after shipment. The control unit 6 responds to the control signal of the serial communication interface 3. Select either BANK0 or BANK1 correction data.
Here, in this specific example, BANK0 in which correction data is written at the time of shipment from the factory is set to write prohibition so that the user cannot rewrite.
The detailed configuration of the EEPROM 7 will be described later.
[0018]
In the specific example, the serial communication interface 3 executes various processes corresponding to commands included in the input reception signal.
Specifically, read / write control is performed on the EEPROM 7 as will be described in detail later.
[0019]
Next, the configuration of the EEPROM 7 and the configuration of the serial communication interface 3 for performing data read / write control of the EEPROM 7 will be described in detail.
As shown in FIG. 3, the serial communication interface 3 includes a write protect control unit 3f and a command control unit 3a including an address register 3b, a control register 3e, and AND circuits 3c and 3d.
The reception signal RXD input to the serial communication interface 3 includes a command (write command) for instructing data writing to the EEPROM 7 and write communication data, and is input to the command control unit 3a.
Further, as shown in FIG. 3, the write communication data includes start address data (designated as Start Address in FIG. 3) and write data (designated as WRITE DATA in FIG. 3) for designating a write position. Is included).
[0020]
In the serial communication interface 3, the command control unit 3a receives command data (WP setting / cancellation) for canceling the write prohibition setting in the control register 3e when a reception signal RXD including a command (write command) instructing writing is sent. Command data), the most significant bit A12 of the start address data is output to the address register 3b, 1 is output to the AND circuit 3c, and write communication data is output to the address decoder 7c of the EEPROM 7.
Here, when the most significant bit A12 is 0, it indicates that the ROM writing area is BANK0, and when it is 1, the ROM writing area is BANK1.
In the present invention, the number of BANKs in the EEPROM 7 can be 2 or more. In this case, the upper 2 or 2 or more bits may be used for data specifying each BANK.
[0021]
The control register 3e is set in advance in a write-inhibited state and normally outputs 0 indicating the state to the AND circuit 3d, but command data for releasing the write-inhibit setting from the command control unit 3a (WP setting / release command data). Is input, 1 is output to the AND circuit 3d to indicate that the write inhibit state has been released.
The AND circuit 3d outputs 1 to the AND circuit 3c when 1 indicating BANK1 is input via the address register and 1 is input from the control register 3e to cancel the write inhibit state.
[0022]
The AND circuit 3c inputs 1 to the XWP of the EEPROM 7 when 1 is input from the command control unit 3a and 1 is input from the AND circuit 3d, and 0 is input otherwise. The EEPROM 7 cancels the write inhibit state when 1 is input to XWP (WP-OFF), and maintains the write prohibit state when 0 is input to XWP (WP-ON).
Here, the write protect terminal XWP of the EEPROM 7 is a terminal for performing valid / invalid control of data writing. When XWP = 0 (Low Level), data writing to the EEPROM becomes invalid and the write protect state is set. When XWP = 1 (High Level), data writing to the EEPROM becomes valid and the write protect state is set. .
Further, the write switching between BANK0 and BANK1 in the EEPROM 7 is performed by the address decoder 7c based on the most significant bit A12 included in the write communication data.
[0023]
The BANK to be read can be selected in the same manner as in the case of writing using the most significant bit A12.
That is, it can be performed by the address decoder 7c of the EEPROM 7 based on the most significant bit A12 included in the write communication data input from the command control unit 3a.
Here, an example is shown in which the path width of the address is 13 bits. However, even in the case of 13 bits or more or less, BANK can be designated by the most significant bit.
[0024]
With the EEPROM 7 and the serial communication control interface 3 configured as described above, the correction data of BANK0 of the EEPROM 7 is always protected, the correction data of BANK1 can be rewritten by the reception signal RXD, and either BANK1 or BANK0 can be rewritten. You can select and read correction data. In the above description, the case where the EEPROM 7 is directly connected and controlled by the serial communication control interface 3 has been described. However, the case where the EEPROM 7 is connected via the control unit 6 as shown in FIG. Can do.
That is, each control signal from the serial communication control interface 3 to the EEPROM 7 to the EEPROM 7 is simply input to the EEPROM 7 via the control unit 6 as in the case of direct connection, and the correction data read from the EEPROM 7 is the same as that of the EEPROM 7. The data is branched by the control unit 6 connected between the serial communication control interfaces 3 and input from the control unit 6 to the shift register 10 of the LED driver 2.
[0025]
The reception signal RXD received by the serial communication control interface 3 is input from an external controller (not shown), and for example, correction data read from the EEPROM 7 is input from the serial communication control interface 3 as shown in FIG. The transmission signal TXD can be output to the external controller.
[0026]
In the display device of the specific example of FIG. 2 configured as described above, the image data, the vertical synchronization signal Vsync, and the horizontal synchronization signal Hsync are input to the command control unit 5 via the image data input unit (not shown). Is done. The input image data is input from the command control unit 5 to the correction circuit 8b of the LED driver IC2.
The vertical synchronization signal Vsync and the horizontal synchronization signal Hsync are input to the control unit 6, the correction circuit 8 b and the drive unit 8 a of each LED driver IC 2, and the common driver 4.
Here, the control unit 6 controls each component of the display device in synchronization with the input vertical synchronization signal Vsync and horizontal synchronization signal Hsync.
[0027]
The correction data read from BANK0 or BANK1 of the EEPROM 7 according to the received signal input to the serial communication interface 3 is sequentially transferred to the shift register 10 based on the control of the control unit 6.
The correction data transferred to the shift register 10 is input to the correction circuit 8b via the corresponding register 9 after the correction data for one line has been transferred. That is, image data and correction data corresponding to the image data are input to the correction circuit 8b.
The image data input to the correction circuit 8b is corrected based on the correction data in the correction circuit 8b, and then input to each drive unit 8a as gradation data.
Then, based on the corrected image data (gradation data), LEDs of a predetermined line of the LED dot matrix 1 are turned on by the common driver 4 and each drive unit 8a, and an image is displayed based on the image data. .
[0028]
As described above, in the image display device of the specific example according to the present invention, the correction data stored in the BANK0 of the EEPROM 7, for example, stored at the time of factory shipment can be protected from being erased, and the writable BANK1 is used. Thus, for example, correction data corrected on the user side according to the use environment can be stored, and any correction data can be selected as necessary to correct the image data.
Further, according to the configuration of the embodiment and the specific example according to the present invention, for example, it is possible to configure by using one storage element made of EEPROM or the like without providing two storage elements such as ROM and EEPROM. So it can be small.
[0029]
In the above specific example, the case where the EEPROM 7 has the write prohibition setting function (WP function) has been described. / Non-write can be controlled. For example, when the write enable XWE is LOW pulse active and the serial communication interface receives a write command in the write prohibited state, the same function can be obtained by always setting the XWE to the HIGH level.
[0030]
That is, the present invention is not limited to the configuration of the above-described embodiment and specific example, and has at least one correction data storage unit, and the correction data storage unit can be rewritten with an area that cannot be rewritten. As long as it is provided with a large area.
Further, various modifications can be made to the control of the non-rewritable area and the rewritable area in the correction data storage unit.
In addition, it is preferable to apply this invention to the LED unit which divides and displays a part of all the images which should be displayed on a large sized LED display. For example, when replacing some LED units in a large display for which correction data for the second area has already been set according to the user's usage conditions, only the replaced LED units are adjusted and written to the second area. This is because readjustment according to the use conditions of the user can be easily performed.
Furthermore, the present invention is not limited to an image display device using LEDs.
[0031]
【The invention's effect】
As described above in detail, in the image display device according to the present invention, the correction data storage section stores the first area in which the first correction data is stored in advance and writing is prohibited, and the writable second area. Therefore, a plurality of correction data can be stored in one correction data storage unit.
Therefore, according to the image display device of the present invention, it is possible to store correction data in accordance with the use conditions of the user in the second area, and for example, correction data set at the time of factory shipment and correction set arbitrarily. Image data can be corrected by selecting either of the data.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram conceptually showing the structure of an image display apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a specific example image display apparatus according to the present invention.
3 is a block diagram showing a detailed configuration of an EEPROM and a serial communication interface in the specific example of FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... LED dot matrix display part, 2 ... LED driver IC, 3 ... Serial communication interface, 3a ... Command control part, 3b ... Address register 3b, 3c, 3d ... AND circuit, 3e ... Control register, 4 ... Common driver, 5 ... Command control unit 6, 25 ... Control unit, 7 ... EEPROM, 7a ... BANK0, 7b ... BANK1, 7c ... Address decoder, 8a ... Drive unit, 8b ... Correction circuit, 9 ... Register, 10 ... Shift register, 21 ... Display unit 22 ... Vertical drive unit 23 23 Horizontal drive unit 24 Image data correction unit 26 Correction data storage unit 27 Image data input unit 28 Communication control unit 30 Buffer memory

Claims (5)

An image display device for collecting a plurality of LED units to constitute an LED display,
The image display device includes a display unit in which light emitting diodes are arranged in a matrix of m rows and n columns, a correction data storage unit that stores correction data corresponding to each light emitting diode, and input image data as described above. A control drive circuit that corrects based on the correction data and displays the image on the display unit using the corrected image data ,
The correction data storage unit is comprised advance first region in which the first correction data is stored and write is prohibited, the one storage element and a writable second region, constituting the LED display An image display device , wherein when replacing some of the LED units, correction data of the LED unit to be replaced is written in the second area .   The image display device according to claim 1, wherein the correction data storage unit includes a nonvolatile memory capable of electrically erasing and writing data.   The image display device further includes a communication control unit configured to write second correction data different from the first correction data to the second area and to prohibit writing to the first area. Item 3. The image display device according to Item 1 or 2.   The image display device according to claim 1, wherein the writable second area can be set to write prohibition.   The correction data storage unit stores correction data of the light emitting diode so that the address and each light emitting diode correspond to each other, and the first and second areas are identified by upper bits of the address. 5. The image display device according to claim 1.

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