JPS60107093A - Multicolor display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a display device using light emitting diodes, and in particular, when performing multicolor display by combining a plurality of light emitting diode units emitting different colors, the present invention relates to display devices using light emitting diodes. The present invention relates to a multicolor display device that can display images with uniform brightness.

[Prior art]

2. Description of the Related Art Conventionally, multicolor display devices have been known in which light emitting diodes that emit light of various colors such as red, green, or yellow are formed into units and these light emitting diodes are combined to perform multicolor display. However, in this type of display device, when displaying three colors of red, green, and yellow using a combination of two-color light emitting diode units, for example, red and green, it is difficult to display the yellow color. In addition, a constant current is supplied to each red and green light emitting diode unit to keep them lit at all times, which requires twice the current consumption and doubles the amount of light, increasing power consumption.
There was a drawback that the brightness of each display color was non-uniform.

[Object and structure of the invention]

In view of the above points, the present invention has been made to eliminate these drawbacks.The purpose of the present invention is to improve the brightness of each display color when displaying multiple colors by combining a plurality of light emitting diode units emitting light of different colors. An object of the present invention is to provide a multicolor display device that can make the color uniform and reduce power consumption.

In order to achieve such an object, the present invention provides a driving means comprising at least two or more light emitting diode units emitting light of different colors, a switching element for driving each of these light emitting diode units, and a driving means for driving the driving means. and signal generating means for generating a drive signal for selectively driving each switching element based on color information, the signal generating means generating a constant drive signal corresponding to a single color information. and drive each of the light emitting diode units to emit light, and when the color information is a combination of at least two, each of them generates a drive signal with a duty of one integer fraction of the number of combinations. The light emitting diode units are alternately driven to emit light depending on the situation. Embodiments of the present invention will be described in detail below with reference to the drawings.

〔Example〕

FIG. 1 is a schematic circuit diagram showing an embodiment of a multicolor display device according to the present invention, in which a red light emitting diode unit (hereinafter referred to as an LED unit) and a green LED unit are used for multicolor display. The following shows a case where three-color display is performed. In the same figure, 1 is a red LED unit, 2
is the green LED unit, 4 is these LID unit 1
, 2 are selectively driven by output signals sent from a clip-flop to J-, which will be described later. .

63 and base resistors 71 to a2, and supplies current from a constant current power source 10 to the LED units 1 and 2 through the respective switching elements 61 and 6 to drive them.

Further, 11 is a flip-flop with reset and preset J-, and a clock of a predetermined frequency is input from the oscillator 12 to its clock terminal CK, and the input terminal J
, are commonly given a constant potential of 10 V. In addition, two color signals R and G, red and green, are selectively input to the reset terminal Re and the preset terminal P through the logic 1 circuit 15 consisting of NAND circuits 16 to 18 as color information input to the input terminals 13 and 14. The high level of the color signals R and G input to the reset terminal Rev preset terminal P is ``H'', and the low level is ``L''.
Then, the above J- clip-flop 11 operates as shown in Table 1, and the drive circuit 4 operates based on each output Q, Q.
The switching element t+, 52 is driven.

First, the operation of the above embodiment will be explained. Here, the red LE
When making D unit 1 emit light, input terminals 13 and 1
The red signal R of the color information input to 4 is "H", and the green signal G is "
When the output becomes "L", the output of the NAND circuit 1T of the logic circuit 15 becomes "L", and the output of the AND circuit 18 becomes "H". is input. Then, as shown in Table 1, the output Q of the J-7 lip-flop 11 is "L" and the output Q is "H". The switching element 5 is turned on, and the switching element 6! is also turned on.As a result, a constant current is supplied from the constant current power supply 10 to the red LED unit 1.
is always lit in red.

In addition, when the green LED unit 2 is made to emit light, the red signal R of the input terminals 13 and 14 is "L°", and the green signal G is "L°".
becomes w', so the inputs of the reset terminal R and preset terminal P of the flip-flop 11 to J- are H°',
The outputs Q and Q are respectively “H”.
Therefore, the switching elements 52 and 62 are turned on by the output Q of this HIT, and the LED unit 2 is driven by the current from the constant current circuit 10 and constantly lights up in green for display.

In addition, when making the red and green LED units 1 and 2 emit light, the red signals R of the input terminals 13 and 14 are set to "H",
The green signal G becomes "H". Therefore, the outputs of the NAND circuits 17 and 18 of the logic circuit 15 are both "H", and these 'H' signals are input to the reset terminal Re + preset terminal P of the flip-flop 11 at J-. Then, at J-, the output Q of the flip-flop 11 is the clock (
The pulse and pulse of the duty IA shown in Figure 2 (b) are synchronized with the falling edge of the whistle (see Figure 2 (a)), and its output Q is the second
As shown in Figure (e), the pulse is inverted. As a result, the switching elements sz, 62 and St, L of the drive circuit 4 are turned on alternately based on the pulses of the outputs Q, Q from the flip-flop 11.

Drive off. Therefore, each of the LAIF units 1 and 2 also emits light alternately, and can be displayed in yellow, which is a mixture of these red and green colors. Therefore, at this time, red,
Since the green LED units 1 and 2 are not lit all the time, but are lit alternately with pulses of duty 1/2, both the current and the amount of light are the same as in the case of a single color.
As a result, power consumption can be reduced and the brightness of each display color can be made uniform.

In this case, insert a balancing resistor into each IJD unit 1 and 2 to adjust the amount of light due to the difference in luminous efficiency of each LED.Also, the power source is not limited to a constant current power source, but can also be a constant voltage power source. It may be independent for each LIM unit.

FIG. 3 is a circuit diagram showing another embodiment of the multicolor bottom water device according to the present invention, in which a red LED unit 1. A case is shown in which a green Lm unit 2 and a blue LED unit 3 are used to display seven colors by combining these three colors. Here, 20 is the input terminal 211 to 213
The B decoder decodes the 3-bit color signals R, G, and B in which red, green, and blue color information is encoded. Assuming that the high level of the 3-bit color signals R, G, and B is "H" and the low level is 'L', the output for these color signals R, G, and B is as shown in the truth table in Table 2. ~■ is obtained.

Table 2 Also, 22 indicates each LED unit 1 to 22 created from a logic circuit to be described later based on each output of the BCD decoder 20.
AND circuits 23a to 23 for selecting a signal to drive 3
1, and 24 is an output circuit consisting of OR circuits 251 to 253 for driving the switching elements 51 to 53 of the drive circuit 4 (according to the outputs of the AND circuits 23a to 231 selected by the selection circuit 22). This OR circuit 251 includes AND circuits 23a, 23d, 231
and 23j, the OR circuit 25□ has outputs from AND circuits 23b, 23e, 23f, and 23, and the OR circuit 253 has AND circuits 23c, 23c, and 23j.
The outputs of 3g, 23h and 23t are respectively input.

Furthermore, 30 is an oscillator that generates a clock of a predetermined frequency, 31 is a hexadecimal counter that counts the clock from this oscillator 30, and 32 is a BCD decoder that inputs the 3-bit output of the hexadecimal counter 31 and decodes it. As shown in FIGS. 4(a) to 4(f), pulses of 2 and 2 are obtained at the output terminals Oo to 05 of the BCD decoder 32 at a constant period. 33 is
Combining the output pulses of the BCD decoder 32, each L
It is a logic circuit consisting of OR circuits 34a to 34f for creating a signal having a predetermined duty to drive the ED units 1 to 3. This OR circuit 34a connects each output terminal 0o, 02 and The OR circuit 34b also outputs the output pulse obtained at 04 to each output terminal O1.
+03 and 05 output pulses are respectively input,
These OR circuits 34a and 34b select output pulses of duty 1//2 when two colors are combined, and AND circuits 23d, 23f, 23h and 23e of the circuit 22.

23g and 23j, respectively. Further, the OR circuit 34c inputs the output pulses of the OR circuits 34a, 34b, and inputs the output pulse of duty 1 to the AND circuits 23a, 23b, and 23c at the time of one color. Then, the OR circuit 34d outputs the output pulses from each output terminal Oo and 03 of the BCD decoder 32 to the OR circuit 34e.
Similarly, the OR circuit 34f receives the output pulses from the output terminals 01 and 04, and the OR circuit 34f receives the output pulse from the output terminals 02 and 05, respectively.These OR circuits 24d to 24f receive the output pulses from the duty IA when combining three colors. The signals are input to AND circuits 23j to 23t, respectively.

Therefore, as color information, for example, a color signal R of "HLL"
, G, and B are input to the BCD decoder 20, this decoder 20 outputs "H" as shown in Table 2.
The output ■ is input to the AND circuit 23& of the selection circuit 22. Then, this AND circuit 23& has the output terminals Oo to 05 of the B decoder 32 as shown in FIG.
Since the output pulses shown in -(f) are sequentially input through the OR circuits 34a to 34c, the AND output is a continuous duty 1 pulse. Therefore, this pulse turns on the switching elements 51 and 61 of the drive circuit 4 through the OR circuit 251, and the red LED unit 1 is driven by the current from the constant current power supply 10, and displays a single red color at all times. Also, “LI(L”),
When the color signals R, G, and B of "LLH" are input to the BCD decoder 20, the output of this decoder 20 is
Or, since ■ becomes VC "H" as shown in Table 2 in accordance with the signal, this output (≧) + (::lj) is input to the AND circuits 23b and 23c, and the same as above is achieved. The green or blue LEI) units 2 and 3 will always be lit in a single color.

On the other hand, color signals R and G of "HHL" are used as color information.

When B is input, the output ■ of the BCD decoder 20 becomes H.
” and is input to the AND circuits 23d and 23e.The AND circuit 23d then receives the BCD decoder 3.
The fourth obtained at the output terminal Oo + 02 + 04 of 2
The output pulses in FIGS. (a), (e), and (e) are input through the OR circuit 34a, and the AND circuit 23
4(b) and (d) similarly obtained at output terminals 0++03+05.

Since the output pulse of (f) is input through the OR circuit 34b, these AND circuits 34d and 34e alternately input the output pulse from the BCD decoder 32 through the OR circuits 25+ and 252 to the switching element 51.
.

61 and 52.62 to turn them on and off. Accordingly, the red and green LED units 1 and 2 are lit alternately based on the output pulses from the AND circuits 23d and 23e, and a two-color display is performed using a mixed color that is a mixture of two colors, red and green. can be done. therefore,
In this two-color combination display, pulse driving by duty IA becomes possible. Also, if the color signals R1G and B of "'LHH"' or "HLH" are input,
The output of the BCD decoder 2o (ω・ or (0 is H'''), the outputs ■ and ■ are respectively connected to the AND circuit 23f,
23g, 23h, and 23i. Therefore, these AND circuits 23f.

23g, 23h, and 23i are the above-mentioned AND circuit 2
3d.

Similar to 23e, the output pulses from the BCD decoder 32 are alternately transmitted to the switching elements 52.5s and 5.

53 and drive them. As a result, the green and blue L units 2 and 3 and the red and blue L units 1 and 3 are lit alternately in the same manner as described above, so that a color that is a mixture of these two colors is produced. Can be displayed.

Furthermore, color signals R and G of "HHH" are provided as color information.

When B is input, the output ■ of the BCD decoder 20 becomes nHn and is sent to the AND circuits 23j, 23 and 23t.
is input. Then, this AND circuit 23j has B
The output pulse of FIG.
d, and each AND circuit 23k, 2
31 has an output terminal OH+ from 04 (Fig. 4 can), (
The output pulse shown in e) is input through the OR circuit 34e, and the output pulse shown in FIG.
The output pulse shown in (f) is input through the OR circuit 34f. Therefore, these AND circuits 23r to 231
The output pulses from the BCD decoder 32 are sequentially passed through OR circuits 25t to 253 to switching elements 51 to 5.
3 and drive them. For this, it's red.

The green and blue LED units 1 to 3 are sequentially lit based on the output pulses of the AND circuits 23'' to 231,
Displays can be made by combining these three colors with white, which is a mixture of red, green, and blue. Therefore, in this three-color combination display, pulse driving with a duty of 1/3 is possible.

In this way, according to the embodiment described above, seven colors can be displayed using the red, green, and blue LED units 1 to 3 using a combination of each single color, two colors, and three colors.

Note that the present invention is not limited to the embodiments described above, and can be applied to various display devices by combining a plurality of LED units of any emission color. For example, FIG. 5 shows an example in which the present invention is applied to an automobile lamp for indicating the tail, turn, and back of an automobile. That is, as shown in FIG. 5, the display surface 41 of the lamp 4o is divided into three zones 41a to 41c: tail, turn, and back, and a red LED unit (42a) is placed in the tail zone 41a, and a red LED unit (42a) is placed in the turn zone 41b. (Two-color yellow LED unit)
42b, and three-color LED units (red, green, and blue) 42e in the back zone 41c are arranged facing each other, and the LED units for each display zone are arranged with a duty of one integer fraction of the number of combinations. When driving, the tail zone 41a is a single red color, and the turn zone 41b is an orange color that is a two-color mixture of red and yellow.
Furthermore, the back zone 41c can be displayed in white, which is a mixture of three colors: red, green, and blue.

In FIG. 5, 43 is a printed circuit board on which each of the LIILD units described above is mounted, 44 is a reflecting mirror member for reflecting the light from each T and ED unit onto the display surface 41, and 45 is a case body for the lamp. .

〔Effect of the invention〕

As explained above, according to the multicolor display device of the present invention,
When displaying multiple colors by combining multiple LED units that emit light of different colors, the brightness of each display color can be reduced by causing each LEI) unit to emit light alternately at a duty that is an integer fraction of the number of combinations. can be made uniform, and
This has the effect of reducing power consumption.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a multicolor display device according to the present invention, FIGS. 2(a) to (e) are timing charts for explaining the operation of FIG. 1, and FIG. 3 is a circuit diagram showing an embodiment of a multicolor display device according to the present invention. A circuit configuration diagram showing another embodiment, FIGS. 4(a) to (f) are timing charts for explaining the operation of FIG. 3, and FIG. 5 is a schematic structural diagram of an automobile lamp showing an application example of the present invention. It is. 1~3・Fist・LE unit, 4・・Drive circuit,
10... 1. Constant current power supply, 11... 7 lip-flops on J-, 12... oscillator, 15... logic circuit, 2o... BCD decoder, 22... selection circuit , 24... Φ output circuit, 301st oscillator, 31...
φHex counter, 32 @” --BCD decoder, 3
2--- BCC decoder, 33 Φ... logic circuit. Patent applicant: Koito Seisakusho Co., Ltd. Agent: Masaki Yamakawa (1 person)

Claims (1)

[Claims] A driving means comprising at least two or more light emitting diode units emitting light of different colors and switching elements for respectively driving these light emitting diode units, and a driving means for selectively driving each switching element of the driving means based on color information. signal generating means for generating a drive signal, the signal generating means generates a constant drive signal corresponding to a single color information to drive each of the light emitting diode units to emit light, and when the color information is at least 2
When there are two combinations, drive signals with a duty of one integer of the number of combinations are generated, and the light emitting diode units are alternately driven to emit light according to these drive signals. Multicolor display device.