JPH0421891A - Information display device - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to improve the reliability of the information display device by automatically changing the light emitting time rate of a light emitting diode in accordance with the mixed color display and single color display of display dots. CONSTITUTION:The information display device is provided with the 1st storage means MEM for outputting signals for driving light emitting diodes d1 to d16 based on stored data and the 2nd storage means PG for sending signals for periodically specifying the ON/OFF of respective diodes d1 to d16 to the 1st storage means MEM and storing them. Thereby, the ON/OFF of the diodes d1 to d16 can be periodically controlled, so that the light emitting time rate of the diodes d1 to d16 in the mixed color display and single color display of display dots can be automatically changed. Consequently, the number of parts of the device can be reduced, the device can be inexpensively constituted and the reliability of the device can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an information display in which display dots, which are a collection of light-emitting diodes with different luminescent colors, are arranged in a matrix shape vertically and horizontally, and dots are arranged to display characters, two figures, etc. It is related to the device.

[Prior Art] Conventionally, information display devices have been widely used in which light emitting diodes are arranged as display dots vertically and horizontally in a matrix, and the light emitting diodes emit light to display letters, figures, etc. in a dotted manner. Regarding the light emitting colors of the light emitting diodes that make up the display dots, two-color light emitting diodes of red and yellow-green sealed in a transparent resin lens may be used, or single-color light-emitting diodes of red, yellow, and green may be assembled to emit light of each color. It emits light in a single color of red, a single color of yellow-green, or a mixture of red and yellow-green to display multiple colors such as orange.

[Problems to be Solved by the Invention] Looking at the brightness of monochromatic display and mixed color, in monochromatic display only the light emitting diodes of the corresponding color emit light, but in mixed display the light emitting diodes of multiple colors emit light, so the brightness is mixed. The colors will be brighter. Therefore, when monochromatic areas and mixed areas coexist on the same display surface, there is a problem in that relatively bright areas and dark areas occur.

Furthermore, when comparing the heat generated from the light emitting diodes, in monochrome display, current flows only through the light emitting diodes of the corresponding color, so the heat generation is less than in the case of mixed display. On the other hand, as shown in Fig. 5, the allowable current of a light emitting diode can be increased if the ambient temperature is low, and as shown in Fig. 6, the luminous intensity of the light emitting diode is almost proportional to the current value. It is possible to increase the luminous intensity by flowing a large amount of current through the light-emitting diodes that make up the display dots of a monochrome display, but the light-emitting diode drive circuit is connected from the power source EO to the limiting resistor R as shown in Figure 7.
Since the current flowing through the light emitting diode D1 is controlled by the switch SWI which controls the on/off of the current through the
If the forward voltage drop of the light emitting diode is El, then I=(EO-El)/R1. Therefore, in order to change the current value between monochrome display and mixed display, it is necessary to switch the limiting resistor R1 or the power supply voltage EO between monochrome display and mixed display, which increases the number of parts, making it expensive and reducing reliability. There were problems such as a decrease in

In addition, as disclosed in Japanese Patent Application Laid-open No. 63-182694, in the case of a mixed display, light is emitted by a pulse signal, and as a result, the luminous intensity of the monochromatic light emitted by the light emitting diode is reduced by reducing the time rate of emitting light. There are proposals to lower it. However, in this case, an AND circuit 5b for determining whether monochrome display or mixed display is required for each display dot, and gate circuits 5c and 5d for emitting pulsed light are required, which also increases the number of parts. As a result, there was a problem that reliability decreased.

[Means for Solving the Problems 1] In order to solve such problems, an information display device according to the present invention includes a first storage means that outputs a signal for driving a light emitting diode based on stored data; and second storage means for sending and storing a signal to the first storage means periodically specifying whether the light emitting diode should be turned on or off.

Further, while the first storage means is driving the light emitting diode, the second storage means
The third storage means receives and stores a signal from the storage means periodically specifying whether the light emitting diode should be turned on or off, and instantaneously transfers this signal to the first storage means. .

[Function] The lighting and extinguishing of the light emitting diodes is controlled periodically, and as a result, the light emitting time rate of the light emitting diodes can be automatically changed between mixed color display and single color display of display dots.

Furthermore, since the third storage means instantaneously transfers the signal for periodically specifying the lighting and extinguishing of the light emitting diodes to the first storage means, no display disturbance occurs.

[Example] Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an information display device of the present invention. In the figure, LDI to LD8 are red light emitting diodes (hereinafter referred to as LEDs) d], d2. ,,,,
The two-color LEDs d8 and the yellow-green LED d9°dlo, . . . , d16 form a display dot as a two-color LED.

The cathodes of the LEDs dl to d16 of the display dots LDI to LD8 are connected in common to the negative side of the power supply E, and the anodes of the LEDs dl to d8 are connected to the outputs D1 to D8 of the latch circuit LT1. LED
The anodes of d9 to d16 are the output D of the latch circuit LT2.
9 to D16. Latch circuit LTI, LT
2 receives signals from inputs 1 to 116, respectively, and outputs a signal of state [1] at terminals LL and L2 to input I].

- Ii6 are latched and outputted to outputs D1 to D16, respectively.

Inputs 11 to 16 are shift registers S R1-.

They are connected to parallel output terminals Q1 to Q16 of SR2, respectively, and shift registers SRI and SF? .

2 shifts the data of the input terminals INi and IN2 to the right at the rising pulse of the state "1" signal of the clock pulse input terminals CPI and CP2, and outputs the shifted data to the parallel output terminals Q1 to Q16. .

Terminal INI of shift register SR1 is connected to OR circuit ORI.
It is connected to output terminal 05 of shift 1 to register S.
A terminal IN2 of R2 is connected to an output terminal 06 of an OR circuit OR2. In addition, shift registers SRI and SR2
The terminals CP], CP2 are connected to the CP terminal of the pulse generator PG. One input of the OR circuit ORI is
The other input is connected to the output of AND circuit A1, and the other input is connected to the output of AND circuit A2. Further, one input of the OR circuit OR2 is connected to the output of the AND circuit A3, and the other input is connected to the output of the AND circuit A4. One input of the AND circuit A1 is connected to the memory output terminal 01 of the memory circuit MEM, and the other input is connected to the terminal F of the pulse generating circuit PG.

The signal at the terminal F of the pulse generation circuit PG is output from the AND circuit A1.
In addition to the input of AND circuit A3, the input of inverter IN
AND circuit A2. via VI and INV2. A, 3rd of 4
is being input to the input terminal. In addition to the input of the AND circuit A1, the terminal 01 of the memory circuit MEM is also connected to the AND circuit A1.
The first input of the AND circuit A4 is connected to the second input of the AND circuit A4 via the inverter INV4. The second input of the AND circuit A2 is connected to the memory circuit M via the inverter INV3.
It is connected to the memory output terminal 02 of the EM, and the terminal 02 is also connected to the input of the AND circuit A3 and the AND circuit A4.
is connected to the first input of the .

Furthermore, the memory circuit MEM includes memory elements Ml and M2, each having a clock input terminal CP3. C.P.
4, and the state of the terminal CP of the pulse generator PG is "1".
It receives the rising pulse of ", shifts the internally stored data to the right, and outputs them to terminals 01 and 02, respectively. Specifically, it is composed of a shift register. These memory elements Ml and M2 are connected to LEDs d1 to LD8 of display dots LDI to LD8 by the microcomputer CPU.
Data specifying the light emission of d16 is stored in advance.

That is, the memory element M1 includes red LEDs d1 to d8,
Furthermore, data specifying light emission of the yellow-green LEDs d9 to d16 is stored in the memory element M2. Then, the state of the stored data in the memory elements M1 and M2 is rl.
, rQ''.

Next, FIG. 2 is a diagram showing the timing of waveforms of each part of this information display device. In the same figure, (1) the figure shows the clock signal at the terminal CP of the pulse generator PG, (2) the figure shows the signal at the terminal Ol of the memory element M1, and (3) the figure shows the signal at the terminal CP of the memory element M2. 02 signal, and (4) figure,
(5) The diagram shows the terminals of pulse generator PG and terminal F, respectively.
The signals in (6) and (7) are OR circuits OR1,
The signals at output terminals 05.06 of OR2 are shown, and FIGS. (8) to (17) show signals at output terminals D1 to D13 of latch circuits LTI and LT2, respectively.

In FIG. 2, in the interval of time t1, the pulse generator P
Eight pulses are output from the G terminal CP. The memory circuit MEM has terminals CP3. When this pulse signal is received from CP4, the data is shifted to the right and the state "1" is output only when the 6th and 8th pulses are received at terminal 01, and the state "0" is output at other times. Output. Similarly, the output from terminal 02 is in the state shown in (3). At this time, the terminal F of the pulse generator PG is in the state "1".
”, so AND circuit A1 and AND circuit A
3 gates are opened. Therefore, the states of the terminals 05 and 06 are as shown in FIGS. (6) and (7).

Shift registers SRI and SR2 have terminals CP1 and CR2.
Since each receives a clock signal from the terminal CP of the pulse generator PG, the signals sent from the terminals 05 and 06 are shifted to the right, and when eight pulse signals are received from the terminal CP, the memory element Ml , M2 are transferred to the shift registers SR, , 1, , SR2, respectively.

Next, when a signal of state "1" is output from the terminal of the pulse generator PG, the output Q of the shift register SR1゜SR2
The data from Q1 to Q1-6 is sent to the latch circuit LT1. ．． L
latched at T2, and its output terminals D1 to D16
, signals as shown in figures (8) to (13) are output. That is, terminal D1. ．． D3. DIO,Dll
are in the state "1", and the LEDs dl, d3 . of the display dots connected to them respectively. dlo and dll will emit light. As a result, the display dots I-LD1 are displayed in red, LD2 is displayed in yellow-green, and LD3 is displayed in a mixture of red and yellow-green, and the other display dots are not displayed.

Next, in the period of time t2, the terminal F of the pulse generator PG
Since the state of A2. is "0", the AND circuit A2. The third input of A,4 becomes state "1", and the AND circuit Ai,
A3 gate is closed.

AND circuit A2 has terminal o2 when the state of terminal 01 is "1".
Outputs "1" when the state of is "0". That is,
When there is data that causes only the red LED to emit light, change the status to "
1'', and the AND circuit A4 assumes that the state of terminal 02 is r]-
” and the state of terminal 01 is “0”, the state “1-” is output. That is, the state is set to "1" when there is data that causes only the yellow-green LED to emit light. Therefore, terminal 05,
The state of 06 is as shown in the figure.

In shift registers SR1, SR,2, terminal CP
I, CP2 each receive a pulse signal from terminal CP, and the signal at terminal 05.06 is shifted to the right to receive eight pulses from terminal CP, and memory element M1. ．． M
If the state of the two signals becomes "11" at the same time, change the state to "11".
o'' and transferred to shift registers SRI and SR2.

Next, when a signal of state "1" is output from the terminal of the pulse generator PG, the data of the outputs Q1 to Q16 of the shift registers SR1 and SR2 are transferred to the latch circuits ■, Tl, L, T2.
, and the output terminals D1 to D16 have <8
) to (13) The signals shown in the figure are output. In other words, only the terminals Di and D10 are in the state "1" and the other terminals are in the state "0", so the LEDs dl and dlo of the display dots connected to them respectively emit light, and as a result, the display dot LDI is red. , LD2 are displayed in yellow-green, and other display dots are not displayed.

Then, if the sections of time tl and t2 are alternately repeated at high speed, the display dot LD1 becomes red due to the afterimage phenomenon to the naked eye.
LD2 appears to be lit in yellow-green, and LD3 appears to be lit in red and yellow-green, respectively.

These sections tl and t2 are the same time, and the LEDs d1 to d
1.6 When the instantaneous value of the current flowing through the dots is set to the same value j2, the LEDs di and dlO of the display dots LD1 and LD2 are as follows.
Since the current flows continuously, the current is the same. LEDd3 of display dot LD3. In dlo, a current of value 12 flows in each period of time t1, and no current flows in the period of time t2, so the average current value in period T as a display dot is 12x2xtl/(tl+t2), and times t1 and t2 are Since the times are the same, they are equal to each other, and therefore the average current value is j2.

As a result, display driver 1-LDI and LD2 have the same value. Therefore, the current flowing through each display dot is the same when the display dot is displayed in a single color and when it is displayed in a mixture of two colors, and problems such as visibility due to differences in luminous intensity and current reduction due to temperature rise are avoided. Solvable.

Here, the times tl and t2 are the same time, but either one may be a longer time. In this case, the intervals tl,
At t2, the light emitting diode may be repeatedly turned on and off, and the luminous intensity may be changed by changing the light emitting time rate of each light emitting diode. In addition, the shift 1 register SRI and latch U'i circuits i, TI, etc. are integrated into ICs and are commercially available with model names such as TC748C595, so using these makes it easy to downsize, and
The device can be constructed at low cost.

Next, FIG. 3 is a block diagram showing another embodiment of this information display device. In this figure, parts equivalent to those in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted. In FIG. 3, the input of inverter TNV2 is connected to terminal F, and the output of this inverter TNV2 is connected to the input of AND circuit A3. That is, in FIG. 1, the inverter INV2 is connected to the third input of the AND circuit A4, but in FIG. 3, it is connected directly to the terminal F.

Timing charts 1 to 1 of the apparatus configured as described above are shown in FIG.

In FIG. 4, terminals 01, 02 . The states of the signals L, F, and 05 are the same as in FIG. 2, but the states of the signal at terminal 06 and the signal at terminal Dll are different from those in FIG.

That is, the interval t1. At t2, the state of the signal at terminal 06 and the state of the signal at terminals D], ] are interchanged with the states shown in FIG. With this configuration, the current flowing to the display dot LD3 flows to dll in the 1,1 interval, and to d3 in the t2 interval, and the current does not flow to these at the same time.

Further, this average current can be set to 12, which can be the same value as the other display dots LDI and LD2.

Furthermore, by making the interval t1 longer than the interval 2, it is possible to increase the light emitting time ratio in the period T of the LED dll- of the display dot LD3, so by changing the yellow-green color to a stronger one, the mixed display can be achieved. You can change the color. Conversely, by making the period t2 longer than the period t1, the hue of the display dot LD3 can be changed to a stronger red hue. Furthermore, in this embodiment, current does not flow simultaneously through the red LED and the yellow-green LED constituting the display dot, so no excessive current flows instantaneously from the power source E.

As explained above, in this embodiment, the first memory is composed of a latch circuit that outputs a signal for driving the light emitting diodes to control lighting/extinguishing of the light emitting diodes constituting the display driver 1. circuit, and a shift register that transfers the output for controlling the lighting and dimming of the next light emitting diode from the memory circuit MEM (second memory circuit) while the light emitting diode is being driven by the memory output of the first memory circuit. and a third storage circuit configured as shown in FIG. That is, in order to control the lighting and dimming of the light emitting diode for each display dot in the t1 period and the t2 period, these data are stored in the first storage circuit each time from the storage circuit MEM in which they are stored in advance. However, the memory circuit MEM
To transfer data from the first storage circuit to the first storage circuit, it takes the clock pulse time x the number of display dots, and during this transfer the light emitting diodes are turned on and off according to the signal flow. If the number of displayed dots is large, the display may become distorted. However, as in this embodiment, such display disturbances can be eliminated by transferring data to the third storage circuit and then instantaneously transferring it to the first storage circuit with one pulse. In addition, when performing monochrome display and mixed display for each display dot, the display dots can be controlled by transmitting a signal that specifies whether to turn on or off the LED for each emitted color of each display dot and repeating the lighting-off control. The current flowing through each L E l) can be made uniform.

In this embodiment, when data of two memory elements M1 for red color and memory element M2 for yellow-green color are transferred as elements of the memory circuit, the memory elements M1, M, 2 are transferred in the interval between times tl and t2. However, there is also a method in which red data and yellow-green data are further divided into time t1 and time t2 and stored in the storage element in advance. Further, in this embodiment, the display driver 1 to which has two-color LEDs emitting light of red and yellow-green has been described as an example, but other colors may be used, or a three-color I-ED may be used.

[Effects of the Invention] As explained above, the information display device of the present invention has a first storage means that outputs a signal for driving a light emitting diode, and a first storage means that outputs a signal to drive a light emitting diode, and a signal that periodically specifies turning on and off of a light emitting diode. A second storage means is provided to send and store the data in the first storage means, and the light emitting time rate of the light emitting diode is automatically changed between mixed color display and single color display of display dots. In addition to automatically eliminating display variations between displays, the device can be configured with a small number of parts, so the device can be configured at low cost, and
This has the effect of improving reliability.

Furthermore, since the third storage means instantaneously transfers a signal specifying whether the light emitting diode should be turned on or off periodically to the first storage means, it is possible to eliminate display disturbances.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the information display device of the present invention, FIG. 2 is a timing chart of this device, FIG. 3 is a block diagram showing another embodiment of this device, and FIG. 4 is a timing chart of this device. , Figure 5 is a graph showing the relationship between the current flowing through the light emitting diode used in this device and the ambient temperature, Figure 6 is a graph showing the relationship between the current flowing through the light emitting diode and luminous intensity, and Figure 7 is a graph showing the relationship between the current flowing through the light emitting diode used in this device and the luminous intensity. FIG. 2 is a circuit diagram illustrating the operation of the information display device. CPU...-Microcomputer, MEM...
Memory circuit, Ml, M2-- Memory element, PG...
Pulse generator, OR, 1, OR. 2...OR circuit, A1-A4...AND circuit,
INVI～Ding NV4・・・Inverter, SRI, SR
2...Shift register, L, T1, LT2...
...Latch circuit, LDI~LD8...Display dot,
dl-~d ], 6... Light emitting diode.

Claims (2)

[Claims] (1) In an information display device that collects a plurality of light emitting diodes with different light emitting colors to form a display dot, and controls the light emitting diodes for each light emitting color to display characters and figures in a dotted manner, stored data a first storage means for outputting a signal for driving the light emitting diode based on the above, and a second storage means for sending and storing a signal for periodically specifying turning on/off of the light emitting diode to the first storage means. storage means, and the light emitting time rate of the light emitting diode is changed between mixed color display and single color display of the display dots by controlling a signal specifying lighting/extinguishing of the light emitting diode. information display device. (2) In the information display device according to claim (1), while the first storage means is driving the light emitting diode, the second storage means periodically specifies whether to turn on or off the light emitting diode. 1. An information display device comprising: third storage means for receiving and storing a signal and instantaneously transmitting this signal to the first storage means.