JPH0369991A - Display device provided with light emitting diode - Google Patents

Abstract

PURPOSE:To facilitate to correct irregularities in the brightness and the hue of each display panel by assembling plural driving circuits and plural brightness adjustment circuits corresponding to the driving circuits to a circuit block, firmly fixing them to a supporting body and connecting the driving circuits to the wiring of the display panel. CONSTITUTION:Plural display panels 1, for example, eight panels are disposed in a left and right direction four by four and two panels are disposed in an up-and-down direction so that they may be nearly adjacent to each other and also they are attached so as to be arranged on one flat plane. And the driving circuits 8 and 9 and the plural brightness adjustment circuits 10 are individually assembled to each one of the circuit blocks at least, each circuit block is firmly fixed by the supporting body 2 where plural display panels 1 are arranged to be attached, a correcting signal set in advance in an electronic controller 7 is given to the corresponding driving circuits 8 and 9 so that the energizing time may be adjusted by the brightness adjustment circuit 10. Thus, the high brightness can be obtained and also the brightness adjustment and the hue adjustment can be very easily performed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a display device using a dot matrix type display panel using light emitting diodes, and more specifically, a display device having a dot matrix type display panel using light emitting diodes. The present invention relates to a display device that can be arranged in both directions to increase the overall brightness, and can also perform individual brightness adjustment and color tone adjustment.

(Prior Art) A display panel in which light emitting diodes are connected to wiring provided in a matrix on a substrate is widely known as one of the means for displaying information such as characters and figures. Then, this dot matrix type display panel displays a predetermined character or figure by sequentially repeating the operation of applying lighting pattern data to the data lines and applying data to the lines corresponding to the pattern of the scan line and lighting them up. It is also widely known that by switching the scan lines at high speed in a time-division manner, it takes advantage of the afterimage phenomenon of the human eye and makes it appear as if the entire device is lit at the same time. There is.

In addition, in order to light up such a display panel, a data line drive circuit, a scan line drive circuit, and an electronic controller that provides signals to these are required. Units are available on the market in which a drive circuit is assembled to a display panel that is arranged in a grid pattern and has matrix-like wiring on the back, and when displaying complex information using kanji, etc. A large number of display panels are arranged.

By the way, when a light emitting diode is lit, it is necessary to make it brighter by increasing the brightness in order to easily read it and understand the content of the information, but the lighting time of one scan line depends on the number of dots. For example, 16x16 dots
In the case of a matrix, the lighting time ratio is 1/16 duty, and as the number of dots increases, the duty becomes a smaller value and becomes darker. As a countermeasure, it is possible to use a high current drive power supply for lighting the light emitting diodes supplied to the scan line, but there is a risk of degrading or destroying the light emitting diodes, so there is a limit, and a protection function is required. There are disadvantages in that the circuit becomes complicated and the price becomes high.

On the other hand, when looking at individual display panels, the light emitting diodes placed on a single substrate are inspected one by one at the assembly stage, and those with the same brightness are selected for use, or the light emitting diodes arranged on a single substrate are inspected one by one, and those with the same brightness are selected for use, or the light emitting diodes arranged on a single substrate are inspected one by one at the assembly stage, or those with the same brightness are selected for use, or those obtained from a specific location on a silicon wafer are used. By selectively using a display panel, unevenness in brightness within a single display panel is eliminated, but when a plurality of display panels are arranged, differences in brightness are unavoidable from display panel to display panel. As a countermeasure, a semi-fixed lighting time adjustment circuit is preassembled in each unit, and after arranging multiple display panels, the brightness can be adjusted by visually checking the brightness difference from the front side and making adjustments on the back side. However, not only do workers have to be placed on both the front side and the back side, but it is extremely difficult to work on the back side where the display panel support structure, wiring, etc. are installed.

Furthermore, when the light emitting diode deteriorates over time or is damaged, the entire unit must be replaced, which is uneconomical.

(Problems to be Solved by the Invention) The present invention solves the problem that commercially available products that are made into a unit by assembling a drive circuit into a display panel with a large number of dots in order to display complex information cannot sufficiently increase the brightness. This is an attempt to solve the problems of the above-mentioned conventional technology, and also solve the problem of the above-mentioned conventional technology that it is extremely troublesome to correct uneven brightness when a plurality of display panels are arranged. It is an object of the present invention to provide a display device in which brightness can be easily measured, brightness adjustment and color tone adjustment can be performed extremely easily, and which is advantageous in terms of maintenance.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a drive circuit connectable to wiring of a dot matrix type display panel using light emitting diodes and a brightness adjustment circuit for setting energization time. A plurality of sets of drive circuits and brightness adjustment circuits are each assembled to at least one circuit block, and the circuit block includes a support body on which a plurality of display panels are arranged and mounted. It is fixed to
The brightness adjustment circuit has a configuration in which a correction signal set in advance in an electronic controller is applied to a corresponding drive circuit to adjust the energization time.

Note that the brightness adjustment circuit is configured to apply a correction signal to either or both of the data line drive circuit and the scan line drive circuit.

In addition, one display panel is on the data line side and the scan line side.
It is preferable to use a matrix in which both line sides are composed of 8 dots.

(Function) Based on the signal from the electronic controller, each drive circuit
By giving a lighting pattern to the lines and switching the scan lines in a time-sharing manner and lighting them up one after another, predetermined characters, figures, etc. are displayed on the display panel. Since the number of output terminals of the drive circuit can be designed to be arbitrary, the number of dots on the display panel attached to the support can be reduced to a small number, and the duty can be increased to achieve high brightness.

In addition, when the display panels are arranged and mounted on a support, a correction signal is created and stored in the electronic controller to eliminate uneven brightness between the display panels, and the brightness adjustment circuit sends the correction signal to the corresponding drive circuit. Give a signal and adjust the energization time.

Further, in the case where the display panel has a configuration in which the light emitting diodes are composed of a plurality of light emitting diodes of different colors and emit a mixed color, the color tone is adjusted by adjusting the energization time of each drive circuit.

(Example) The present invention will be described in detail with reference to the drawings.

FIG. 1 schematically shows the overall arrangement, in which a plurality of display panels 1, for example eight, are arranged almost adjacent to each other, four in the horizontal direction and two in the vertical direction, and aligned on one plane. A first circuit block 3 with a data line drive circuit assembled thereon, a second circuit block 4 with a scan line drive circuit assembled on the back side of a frame-shaped support 2, and brightness adjustment are attached. A third circuit block 5 to which a circuit is assembled is fixed.

The three circuit blocks 3.4.5 consist of a group corresponding to the four display panels 1 on the upper stage and a group corresponding to the four display panels 1 on the lower stage. Four drive circuits each corresponding to block 1,
It has a configuration in which a brightness adjustment circuit is assembled, and a drive power supply line 6a made of a flat wire and a ground NA 6b are arranged orthogonally. Further, the signal lines 31, 41, 51 of each circuit block 3, 4.5 are connected to an electronic controller 7 consisting of a microcomputer.

The display panel 1 has 8×8 dots, and has a lens 12 covering a light emitting diode exposed on the front surface of a substrate 11, and a matrix-like wiring provided on the back surface. Referring to FIG. 2.4, the back surface of the display panel 1 is exposed through the window hole 21 of the support 2, and for example, the eight terminals 14 of the wiring lined up on the scan line are connected to the second circuit block. It is connected to eight corresponding output terminals 91 of four drive circuits 9. Eight terminals 13 of wires lined up on the data line
are similarly connected to the eight corresponding output terminals 81 of the drive circuit 8 of the first circuit block 3. It should be noted that each circuit block 3.4, 5 is provided with heat dissipation means (not shown) such as cooling fins.

Referring to FIG. 4, both the data line drive circuit 8 and the scan line drive circuit 9 include a shift register 82.92, a latch 83.93, and a transistor 84.9.
4, the brightness adjustment circuit 10 is a shift register 10
2, a latch 103, and a comparator 104.

Then, from the electronic controller 7, the clock signal lines 31a, 41a of the signal lines 31.41 and the serial signal f+! 3
1b and 41b input the clock signal and serial signal to the shift register 82.92, and the latch signal line 31c and 41c input the latch signal to the latch 83.
．． 93 to apply the lighting pattern data to the data line and repeat the operation of lighting on the scan line corresponding to the pattern, which is the same as in the conventional method.

On the other hand, when the display panels 1 are attached to the support 2 and arranged, it is unavoidable that differences in brightness and color tone occur between display panels under the same duty lighting time due to variations in the quality of the light emitting diodes.

Therefore, at the inspection stage after assembly, the brightness difference and color tone difference are measured visually, and the energization time per line for each display panel 1 is set so that these are equalized, and this is used as a correction signal. It is written in the memory of the electronic controller 7 as follows. When lighting is performed, a clock signal and an energization time setting signal are input from the electronic controller 7 to the shift register 102 through the clock signal line 51a of the signal line 51 and the energization time setting signal line 51b, and a latch signal is latched by the latch signal ts51c. The basic duty signal for brightness adjustment inputted to the comparator 104 via the basic duty signal line 51d is compared with the brightness setting signal from the latch 103 to create the timing for turning on or off, and this timing signal is used as the data/lighting signal. The signal is output to either or both of the line transistor 84 and the scan line transistor 94 to adjust the energization time.

Note that when one light emitting diode is installed on one dot of the display panel 1 and emits a single color, the brightness is adjusted by the above means, but when a plurality of light emitting diodes are installed on one dot and a mixed color is emitted, the brightness is adjusted. If you want to emit
By separately applying correction signals to the data line transistors provided for each emitted color, color tone adjustment can be performed in addition to brightness adjustment. Therefore, the brightness and color tone of all display panels 1 can be adjusted to be the same, but on the other hand, it is also possible to intentionally change the brightness and color tone, for example, by lowering the brightness of a part or changing the color tone.

It is also theoretically possible to have two output terminals each for the drive circuits on the data line side and the scan line side, and to form the display panel into a 2 x 2 dot matrix.
Considering the complexity of the circuit configuration, the nature of the display panel assembly, and the duty of lighting time, the output terminals of the drive circuit are connected to 8 each.
It is preferable to use an arbitrary matrix in which each individual display panel is composed of 8 dots, for example, a dot matrix of 8×8.16×16.24×24.

Therefore, for example, if a 16x16 dot matrix display panel is used, it will be connected to two drive circuits each on the data line side and the scan line side for lighting, but each drive circuit has eight output terminals. Therefore, the lighting time is 1/8 duty, and even if the number of bits of the display panel is increased, it is easy to increase the brightness by reducing the number of output terminals of the drive circuit. Furthermore, since it is possible to change the lighting pattern input to the shift register, it is possible to light up two or more columns at the same time and further increase the duty of the lighting time.

(Effects of the Invention) According to the present invention, a plurality of data line and scan line drive circuits are assembled into a circuit block, and a drive circuit for a brightness adjustment circuit that provides a signal for adjusting the energization time to the drive circuit is supported. The drive circuit and display panel wiring can be connected by assembling multiple units into a circuit block and fixing them to a support on which the display panels are arranged and mounted, so that the output of one drive circuit is It is easy to make an arbitrarily small number of terminals, and the lighting time duty can be increased to achieve high brightness. Also,
By adjusting the energization time assigned to each line of the display panel by the brightness adjustment circuit, it is easy to correct variations in brightness and color tone from display panel to display panel, or to intentionally change them.

Furthermore, according to the present invention, not only is it possible to mass-produce the circuit blocks by standardizing them, but the display panel and the drive circuit are separate bodies, so there is a great degree of freedom in design and production, and the light emitting diode It is easy to readjust the brightness when deterioration occurs, and it is also advantageous in terms of maintenance because it is only necessary to replace the display panel.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view of an embodiment of the present invention, Fig. 2 is an enlarged partial cross-sectional view of Fig. 1, Fig. 3 is a front view of a circuit block, and Fig. 4 is a display panel, drive circuit, and brightness adjustment circuit. This is a relationship diagram. l...Display panel, 2...Support, 3.4.5...
・Circuit block, 7...Electronic controller, 8.9...
Drive circuit, 10... Brightness adjustment circuit, 13.14...
Terminal, 81°91...output terminal,

Claims (1)

[Claims] 1. A plurality of sets of a drive circuit connectable to wiring of a dot matrix display panel using light emitting diodes and a brightness adjustment circuit for setting energization time; A plurality of circuits are individually assembled into at least one circuit block each, and the circuit blocks are fixed to a support body on which a plurality of display panels are arranged and mounted, and the brightness adjustment circuit is pre-assembled into at least one circuit block. 1. A display device using a light-emitting diode, characterized in that the current supply time is adjusted by applying a correction signal set in an electronic controller to a corresponding drive circuit. 2. The display device according to claim 1, wherein the brightness adjustment circuit is configured to provide a correction signal to either or both of the data line drive circuit and the scan line drive circuit. 3. The display device according to claim 1, wherein the display panel is an arbitrary matrix composed of 8 dots on both the data line side and the scan line side.