JP2883250B2 - Multi-color light-emitting display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-color light-emitting display device, and more particularly, to a multi-color light-emitting display device having light-emitting elements having different light emission intensities such as red, green and blue.

[0002]

2. Description of the Related Art As a display device using a light emitting display element, for example, there is an LED display. This LED display mainly uses a red LED and a green LED. The driving method is dynamic driving when used indoors, and static driving to secure brightness when used outdoors. Is commonly done. Recently, besides the red LED and the green LED, the intensity of the blue LED has also increased compared to before, so that the red, green, and blue
Color display devices using primary color LEDs have also become possible. However, since the intensity of the blue LED is considerably lower than that of the red and green LEDs, static driving must be performed even indoors. Also, when trying to realize a device that drives by changing the duty ratio according to the emission color,
Since it is necessary to input an input signal corresponding to each duty ratio, the control unit for controlling the lighting pattern of the display unit is complicated, and it is difficult to realize the control unit. Therefore, in the prior art, red, green, and blue LEDs are generally driven at the same duty.

FIG. 13 shows a conventional multi-color light-emitting display device. LED constituting the pixel as shown in this figure
The lamp 120 has one drive board S _x per line.
(1 ≦ x ≦ n), and a drive circuit and a terminal group are constructed on each drive board _Sx . Further, these n drive boards _Sx are structured by a mother board M.

[0004]

According to the conventional technique, when a red LED, a green LED, and a blue LED are statically driven, in a display unit of 16 × 16 dots, a terminal from a display unit has one common terminal. 768 lines of display data (16 dots x 16 dots x 3 colors = 768) total 76
Nine are required. Further, the number of drive bits for display data is 768 bits, the number of components of the drive circuit is very large, and this drive portion occupies a very large space with respect to the display area, and it is difficult to reduce the size. Since the number of drive bits is large, the number of parts is large, and there is a problem that cost reduction is difficult.

On the other hand, red LED, green LED, blue LE
When D is dynamically driven, the blue LED must be adjusted to match the intensity of the blue LED with that of the red or green LED.
Requires a current of several hundred mA to flow. However, as shown in FIG. 10, the forward current versus relative intensity characteristic of each of the red, green, and blue LEDs does not increase as compared with the red and green LEDs even if the current is increased. Actually, unless the peak current is suppressed to about 100 mA, there is a risk of element destruction or the like. Therefore, there is a limit to increasing the current in order to obtain emission intensity. Furthermore, the forward current vs. forward voltage characteristics of each of the red, green, and blue LEDs are as shown in FIG.
The power supply voltage for obtaining 100 mA as the forward current for driving the blue LED is 5 V. However, if the drive is actually performed at 5 V, the forward current for driving the red and green LEDs is dramatically increased. Driving is not possible. For this reason, the conventional multi-color light-emitting display device has a problem that the light emission intensity of the blue LED cannot be sufficiently secured.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is intended to improve the luminous intensity of, for example, a blue LED having a low luminous intensity by driving at a lighting interval ratio according to the luminous intensity. It is another object of the present invention to provide a multi-color light-emitting display device having a simple configuration, and capable of reducing the number of drive bits.

[0007]

The structure of the present invention for achieving the above object will be described below with reference to FIG. 1 which is a basic conceptual diagram.

A display section 4 in which a plurality of types of light-emitting elements having different light-emitting intensities based on the difference in light-emitting color are arranged in a matrix, and provided for each light-emitting color. Driver 2 for generating signals
a, 2b, 2c and a multi-color light emitting device according to the first invention in a display device including a control unit 1 for supplying a control signal to each of the drivers 2a, 2b, 2c based on display data supplied from the outside. The display device includes the drivers 2a, 2
b, and between 2c and the control unit 1, the driving circuit 5a which drives at different lighting interval ratio depending on the emission intensity of the light emitting element, 5b, and 5c provided for each emission color Rutotomoni, drive circuit
In 5c, an input signal of a specific lighting interval ratio is applied to another different lighting.
An input signal conversion circuit that converts the distance ratio and drives each light emitting element
Road 3 is provided .

[0009]

Furthermore, multi-color light-emitting display device of the second invention, in the first aspect, characterized by a shift register is used to input the signal conversion circuit 3.

[0011]

The driving circuits 5a, 5b, 5 are driven at different lighting interval ratios according to the light emitting intensity of the light emitting element for each light emitting color.
By c, a control signal is output to each driver so that each light emitting element of the display unit 4 emits a desired light emission intensity.

The input signal conversion circuit 3 converts an input signal having a specific lighting interval ratio into another different lighting interval ratio, and outputs a control signal converted to drive each light emitting element to each driver. Is done. Each of the light emitting elements of the display unit 4 emits light at substantially the same intensity as a driving signal is output from each driver by a control signal for each light emitting color.

Further, a shift register is used in the input signal conversion circuit 3 to transfer and rearrange the input data signals.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an external view of the embodiment of the present invention.

This embodiment is a multi-color light-emitting display device using a color LED as a display plate. As shown in FIG. 2A, this color LED lamp 21 is
A dot matrix unit 20 is formed in which a total of 256 6 dots are arranged in a matrix. As shown in FIG. 2C, the color LED lamp 21
A (Red) G (Green) B (Blue) LED chip 23 is mounted on a metal stem 25, and the chips of each color are resin-molded while being connected to the leads 24, respectively. Silica filler is mixed in the resin used for the resin mold, and each emission color of the RGRLED chip 23 is mixed well. In addition, metal stem 2
5, heat from the RGRLED chip 23 is efficiently radiated. Further, a driver circuit (not shown) for individually driving and controlling the RGB LED chips 23 is constructed on the drive board 22.

FIG. 12 shows a CIE chromaticity diagram in which the chromaticities of the above-mentioned LEDs are plotted. In this figure, a range surrounded by a solid line indicates a range of colors that can be identified by human eyes. The red (R), green (G), and blue (B) colors of the LEDs of each color in the embodiment of the present invention are values obtained by obtaining the points shown in FIG. Therefore, the colors that can emit light according to the embodiment of the present invention are in a range surrounded by a broken line. Note that white (W) is at the position of X = 0.33, Y = 0.33, and in the embodiment of the present invention, the red LED is 50 mA and the green LE is
By supplying 100 mA to D and 50 mA to the blue LED, white light was obtained.

FIG. 4 is a diagram for explaining the connection of the display unit according to the embodiment of the present invention, which will be described below. First, a broken line portion 40 in the connection diagram shown in FIG. 4A shows a configuration of one dot. In detail, one dot corresponding to the broken line part 40 includes one red LED 401 as shown in FIG.
One green LED 402, blue LEDs 403a, 403
It is formed by a total of four LEDs b. The arrangement of each LED constituting one dot is as shown in FIG. By using two blue LEDs in this way, a blue LED that is darker than red and green LEDs
Can be improved. In the embodiment of the present invention,
As shown in FIG. 4A, the LEDs are arranged in 16 dots vertically and 16 dots horizontally, and the red LED and the green LE
D is the dynamic drive (duty ratio 1/16)
The blue LED is connected to a static drive unit (duty ratio 1/1). The number of terminals is 16 red / green common terminals (HD0 to 15) and data terminals (VD0
15) 16 × 2 = 32, one blue common terminal,
Data terminal [BD (0,0) to BD (15,15)] 2
There are 56 289 in total.

Next, FIG. 3 shows a block circuit diagram of an embodiment of the present invention, and the embodiment of the present invention will be described below with reference to FIG. An input buffer 31 for temporarily storing an input signal,
Output buffers 37 for temporarily storing output signals are provided at the input and output portions of the circuit, respectively.

In the green driver integrated circuit 33G, a 16-bit shift register for sequentially transferring the input signal of the data GDATA for driving and controlling the green LED one bit at a time when one line of data (16 bits) is transferred. A latch circuit for latching this one line of data,
The driver is configured to output the data for one line to the output buffer 37 based on the latch signal.

The red driver integrated circuit 33R, like the green driver integrated circuit 33G, includes a 16-bit shift register, a latch circuit, and a driver. These respective integrated circuits 33G, 33
In R, data is transferred bit by bit in the 16-bit shift register by the application of the clock signal CLK, and data of one line corresponding to 16 clocks is transferred. Then, when a latch signal is applied, the signal is output to a predetermined address in the output buffer 37. After that, the driver 36 for each emission color
Drive signals for driving the display unit 38 by R and 36G are output to the display unit 38 and displayed. This driver 36R,
36G is a dynamic drive.

On the other hand, the input signal of the data BDATA for controlling the driving of the blue LED is transferred one bit at a time by the 16-bit shift register 33B for one line. The data for one line is a group of blue driver integrated circuits S ₀ ... S ₁₅ selected to transfer the data.
Is forwarded to In this transfer, the transfer timing is given by a latch signal LE from the timing generation circuit 32 synchronized with the LATCH signal, and BDATA is output by the clock signal CK from the timing generation circuit 32.
Are transferred one bit at a time for one line. The transfer of the data for one line is repeated 16 times to complete the transfer of the data for one frame. The data for one frame is output and displayed on the display unit 38 by the driver 36B.

In the embodiment of the present invention, by providing the input signal conversion circuit 30 including the 16-bit shift register 33B and the timing generation circuit 32, when input data having a duty ratio of 1/16 is driven by static driving, An operation of rearranging input data having a duty ratio of 1/16 to be the same as the data transmission order when driven by dynamic driving is performed. The output timing of the latch signal is RDA
This is equivalent to the output timing synchronized with the TA and GDATA signals.

Therefore, input data having a duty ratio of 1/16 can be output at a duty ratio of 1/1 by rearranging the input data and performing data transmission by the input signal conversion circuit 30.

The rearrangement operation will be described below with reference to FIG.
This will be described in detail with reference to an explanatory diagram of a state where input signals having different duty ratios are transmitted as shown in FIG. In general,
As shown in FIGS. 6A and 6B, the timing of latching differs between the dynamic drive and the static drive. That is, in the case of the dynamic drive, when the duty ratio of the input signal is 1/16, a latch signal is generated every 16 clocks, and this one-line data is output to an address corresponding to a predetermined unit. You. In this case, the input data is "", ""...
, And the transmission order of these data is “
.... Similarly, the duty ratio is 1/16
6D, the data is transmitted in the order of data transmission in the case of performing the static drive, that is, in the order of "", "", "", "",... As shown in FIG. The data is rearranged. As described above, when data is transmitted by static driving, data for 16 lines until generation of a latch signal every 256 clocks as shown in FIG. 6B is continuously output when data is transmitted by static driving. Sent.
In this way, by converting to the data transmission order for performing the static driving, the same data transmission order as in the case of the dynamic driving can be obtained.

Next, a timing chart of the embodiment of the present invention will be described.
Is shown in FIG. 5, and the operation will be described below. RDAT
A, GDATA, and BDATA are CLOCK signals, respectively.
1 bit in each shift register by output of signal
It is transferred one by one. Then, the data is sequentially transferred bit by bit.
When data for 16 clocks is input, LA
A TCH signal is generated. At this time, the internal ENABLE signal
Signal becomes non-active, and then R, G,
R ENABLE signal is turned on and transferred
V_{D (n + 1)}Is the address V_{D (n + 1)}Is forwarded to This
At the time of the next V _{D (n + 2)}Data is entered
You. As described above, RDATA, GDATA, B
As with each input data of DATA, RDAT
The output data of A, GDATA and BDATA are
Output in synchronization with input data. in this way,
The address is switched by the occurrence of the LATCH signal,
Data is loaded to the switched address.

In the embodiment of the present invention, the red and green LEs are used.
The configuration is such that the duty ratio of the D input signal is 1/16 and dynamic driving is performed, and the duty ratio of the blue LED is 1/1 and display is performed by static driving.
In the case of using a blue LED whose emission intensity is further improved, the duty ratio can be appropriately selected such as 1/16 or 1/4.

Further, in the embodiment of the present invention, the rearrangement of data can be realized not only by the shift register but also by using a gate and a selector. Here, as another embodiment of the present invention, a multi-color light-emitting display device using this gate and selector and applied to a collective dot matrix display device will be described below.

FIG. 7 is an external view of another embodiment of the present invention. In this display device, as shown in FIG. 1A, a total of 256 dot matrix display elements 70 of 16 dots in both the vertical and horizontal directions are arranged in a matrix to form a dot matrix unit. The dot matrix display element 70 has an RLE as shown in FIG.
Four, eight, and eight D chips 701, GLED chips 702, and BLED chips 703 are arranged, respectively.
Silicone resin is applied to the upper surfaces of these LED chips, and the silicone resin has a waterproof and heat-radiating effect. These dot matrix display elements 70 are constructed on an LED substrate 72, and a drive substrate 71 for controlling the driving of these elements is provided on the back surface of the LED substrate.

The drive circuit provided on the drive board 71 is configured to dynamically drive the red LED and the green LED with a duty ratio of ８ and a blue LED with a duty ratio of ダ イ ナ ミ ッ ク. FIG. 8 shows a block circuit diagram of this drive circuit, and its configuration will be described with reference to this drawing.

The red driver integrated circuit 83 R
A 32-bit shift register that sequentially transfers an input signal of data RDATA for driving and controlling the ED one bit at a time, and a latch circuit that latches one line of data (32 bits) when one line of data (32 bits) is transferred. It is constituted by. The green driver integrated circuit 83G is similar to the red driver integrated circuit 83R.
It is composed of a 2-bit shift register and a latch circuit. In each of the integrated circuits 83R and 83G, the clock signal C is provided in the 32-bit shift register.
By applying LK, data of one bit is transferred, and data of one line corresponding to 32 clocks is transferred. Therefore, when the latch signal LE is supplied, data for one line is loaded into the storage area of a predetermined address by the address information supplied by the decoder 81, respectively.

On the other hand, an input signal of data BDATA for driving and controlling the blue LED is supplied to the decoder 82 by the decoder 82.
A decoder signal is formed by the signals from A ₀ and A _1, and the gate signal is generated by the decoder signal and the clock signal.
1, G2, G3, G4 either becomes 'High' level, the clock is applied to the predetermined shift register 83B ₁ .about.B _4, is transferred. in this way,
Appropriate BDATA transfers after being transferred to one of the shift register 83B ₁ .about.B _4, the BDATA shift register 83B ₁ .about.B ₄ serially to the next unit by the selector 84.

The output timing 1 /
A two-duty latch signal is generated within this circuit,
The drive data of the three-color LED is output in synchronization with the 1/8 duty latch signal of RDATA and GDATA, and is displayed on a display unit (not shown) by each driver (not shown).

FIG. 9 shows a timing chart of the circuit. BDATA, RDATA and GDATA are
Each 32-bit data is transferred sequentially, but BD
For ATA, 32-bit register 8 every 32 bits
It is transferred to either register 3B ₁ .about.B _4. In this embodiment, before input to these registers by signals from A ₀ and A ₁ , BDATA performs control of information for giving an order for transferring data in units of 32 bits. The data is serially transferred to the next unit. After being rearranged in the data transmission order corresponding to the 1/2 duty ratio in this manner, R
DATA, GDATA, and BDATA are output and displayed on the display unit in synchronization with the timing signal.

In the other embodiment of the present invention, all three colors of data are driven by the dynamic drive circuit, so that the number of terminals can be further reduced as compared with the previous embodiment.

The above-described embodiments of the present invention have been described with respect to the case where three color LEDs are used. However, the present invention is not limited to this. For example, a red LED and a green LED having different intensities are used.
The same applies to the case where two-color LEDs are used.

Further, according to the present invention, the light emitting element is an LED.
Has been described, but the present invention is not limited to this, and the present invention can be similarly realized by using a tungsten lamp.

[0037]

As described above, according to the multi-color light-emitting display device of the present invention, the light emission for each emission color is provided between the driver and the control unit that generate the respective drive signals for the elements of different emission colors. A drive circuit is provided for driving at different lighting interval ratios according to the light emission intensity of the elements, and the driving circuit converts an input signal having a specific lighting interval ratio into another different lighting interval ratio and drives each light emitting element. Since the input signal conversion circuit constituted by the register is provided, it is possible to drive at a lighting interval ratio according to the light emission intensity. For example, when using red, green and blue LEDs, a blue LED having a low light emission intensity is used. Can be improved, and the number of drive bits can be reduced, so that an apparatus having a simple configuration with a small number of parts can be realized. As a result, a multi-color light-emitting display device with high display quality can be obtained, and the cost can be reduced in the manufacture thereof.

[Brief description of the drawings]

FIG. 1 is a basic conceptual diagram showing a configuration of the present invention.

FIG. 2 is an external view of an embodiment of the present invention.

FIG. 3 is a block circuit diagram of an embodiment of the present invention.

FIG. 4 is a diagram illustrating a connection diagram of a display unit and a configuration of one dot according to an embodiment of the present invention.

FIG. 5 is a timing chart of an input signal according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating the output timing of a latch signal and the order of data transmission in data transmission with different duty ratios.

FIG. 7 is an external view of another embodiment of the present invention.

FIG. 8 is a block circuit diagram of another embodiment of the present invention.

FIG. 9 is a timing chart of a circuit used in another embodiment of the present invention.

FIG. 10 is a graph showing forward current versus intensity characteristics of an LED lamp.

FIG. 11 is a graph showing a forward current vs. forward voltage characteristic of an LED lamp.

FIG. 12 is a CIE chromaticity diagram of the LED used in the embodiment of the present invention.

FIG. 13 is an external view of a conventional example.

[Explanation of symbols]

 1 ... Control units 2a, 2b, 2c ... Driver 3 ... Input conversion circuit 4 ... Display unit 5 ... Drive circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G09G 3/00-3/38

Claims (2)

(57) [Claims] 1. A display section in which a plurality of types of light-emitting elements having different light-emission intensities based on a difference in light-emission color are arranged in a matrix, and provided for each of the light-emission colors. a driver for generating a drive signal, in a display device having a control unit for supplying control signals to the respective drivers on the basis of display data supplied from the outside, between the respective driver and control unit, the light emitting
Drives with different lighting interval ratios depending on the color light emission intensity
And a specific point in the drive circuit.
Converts the input signal of the lighting interval ratio to another different lighting interval ratio
And an input signal conversion circuit for driving each of the light emitting elements is provided.
Multicolor light-emitting display device characterized by being. 2. A display section in which a plurality of types of light emitting elements having different light emission intensities based on a difference in light emission color are arranged in a matrix, and provided for each of the light emission colors. And a control unit for supplying a control signal to each of the drivers based on display data supplied from the outside. A drive circuit that drives at different lighting interval ratios according to the light emission intensity of the color is provided, and the drive circuit converts an input signal of a specific lighting interval ratio into another different lighting interval ratio,
A multi-color light-emitting display device comprising an input signal conversion circuit including a shift register for driving each of the light-emitting elements.