CN103839505A

CN103839505A - Liquid crystal color display control circuit and air conditioner

Info

Publication number: CN103839505A
Application number: CN201210486774.0A
Authority: CN
Inventors: 李秉樵; 郑绪成; 陈建昌
Original assignee: Guangdong Midea Refrigeration Equipment Co Ltd
Current assignee: GD Midea Air Conditioning Equipment Co Ltd
Priority date: 2012-11-23
Filing date: 2012-11-23
Publication date: 2014-06-04
Anticipated expiration: 2032-11-23
Also published as: CN103839505B

Abstract

The invention is applicable to the display control field, and provides a liquid crystal color display control circuit and an air conditioner. In the invention, a special color liquid crystal management chip of high cost is saved; a cheap MCU is used to drive a liquid crystal color display; and through a synchronous conversion circuit, a public output end, segment code control output end and a color control output end of the MCU realize synchronous output, and each segment code polling carried out a color display. Because the segment code polling switches quickly, in the eyes of the user, each segment code is displayed continuously; when the invention is realized, the synchronous conversion circuit can be an operational amplifier or an analog to digital converter built in a general MCU, and a synchronous clock signal is obtained by software; and the synchronous conversion circuit can also be a physical circuit arranged outside the MCU. Whatever the synchronous conversion circuit is built in the MCU or arranged outside the MCU, the MCU is a mature product and low in price.

Description

A kind of color liquid crystal display control circuit and air conditioner

Technical field

The invention belongs to demonstration control field, relate in particular to a kind of color liquid crystal display control circuit and air conditioner.

Background technology

In the display screen scheme of all kinds of household electrical appliances, the liquid crystal display adopting is at present generally black-and-white crystal display mode, non-dot matrix color liquid crystal is the development trend in this field cheaply, but present non-dot matrix color liquid crystal generally adopts modular manner, utilize special colour display tube reason chip, its connected mode is as shown in Figure 1: MCU is by the communication interfaces such as SPI and the communication of Special colored liquid crystal managing chip, color liquid crystal managing chip is according to receiving the idsplay order that MCU sends, drive liquid crystal that respective field is shown, drive the color of backlight output liquid crystal display field simultaneously.Although effect is pretty good, but because color liquid crystal managing chip is specific customization, on the high side, in some low-end products, only need simple non-dot matrix chromatic liquid crystal screen, the segment encode quantity that this series products need to show is few, need the color of demonstration also few, adopt color LCD module if basic 8 kinds of color relations can meet the demands, if adopt special color liquid crystal managing chip, can increase cost of products.

Summary of the invention

In view of the above problems, the object of the present invention is to provide a kind of color liquid crystal display control circuit, be intended to solve the technical matters that needs Special colored liquid crystal managing chip that cost is higher in the colored displaying scheme of available liquid crystal, increased production cost.

In order to solve the technical problem, color liquid crystal display control circuit provided by the invention, comprise black-and-white crystal plate, be located at the color backlights of described black-and-white crystal plate bottom and drive the MCU control module of described black-and-white crystal plate and color backlights, described color backlights at least comprises a kind of color LED lamp of color, the color LED lamp of described every kind of color is all connected to the color control output end of described MCU control module by synchronous drive circuit, the public output of described MCU control module and segment encode control output end correspondence are connected to common port and the segment encode control end of described black-and-white crystal plate, as improvement, described color liquid crystal display control circuit also comprises: what be connected with the public output of described MCU control module synchronizes change-over circuit, for changing the output waveform of described MCU control module public output, obtain synchronizing clock signals, control segment encode control output end and the color control output end of described MCU control module and refresh output simultaneously.

The present invention also provides a kind of air conditioner that comprises above-mentioned color liquid crystal display control circuit.

The invention has the beneficial effects as follows: technical solution of the present invention has been saved the higher special color liquid crystal managing chip of cost, realize and drive color liquid crystal to show with low-cost MCU control module, by a synchronous change-over circuit, synchronously export public output, segment encode control output end and the color control output end of MCU control module, and each segment encode poll is colored to be shown.Because the switching of segment encode poll is very fast, user seems that each segment encode shows continuously, and when specific implementation, described synchronous change-over circuit can, for being built in operational amplifier or the analog to digital converter in general MCU, obtain synchronizing clock signals by software mode; Also can be for being placed on the entity circuit of MCU control module.No matter adopt which kind of mode, described MCU control module is all matured product, and price is lower.

Accompanying drawing explanation

Fig. 1 is existing color LCD module control circuit figure;

Fig. 2 is the circuit structure diagram of the color liquid crystal display control circuit that provides of the embodiment of the present invention;

Fig. 3 is the second circuit structure diagram of the color liquid crystal display control circuit that provides of the embodiment of the present invention;

Fig. 4 is color liquid crystal displaying principle schematic diagram;

Fig. 5 is the field schematic diagram of each segment encode on black-and-white crystal plate;

Fig. 6 is the circuit structure diagram of synchronous drive circuit in the color backlights that provides of the embodiment of the present invention;

Fig. 7 is the first exemplary circuit structural drawing of synchronous change-over circuit;

Fig. 8 is the second exemplary circuit structural drawing of synchronous change-over circuit;

Fig. 9 is the third exemplary circuit structural drawing of synchronous change-over circuit;

Figure 10 is the synchronizing signal conversion timing sequence figure of above-mentioned three kinds of synchronous change-over circuits;

Figure 11 is the control chart of the colored backlight sequential that provides of the embodiment of the present invention;

Figure 12 is the another kind of synchronizing signal conversion timing sequence figure of synchronous change-over circuit.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not intended to limit the present invention.

Fig. 2 shows the circuit structure of the color liquid crystal display control circuit that the embodiment of the present invention provides, and for convenience of explanation, only shows the part relevant to the embodiment of the present invention.Referring to Fig. 2:

The color liquid crystal display control circuit that the present embodiment provides, comprise black-and-white crystal plate 1, be located at the color backlights 2 of described black-and-white crystal plate 1 bottom and drive the MCU control module 3 of described black-and-white crystal plate 1 and color backlights 2, described color backlights 2 at least comprises a kind of color LED lamp 21 of color, the color LED lamp 21 of described every kind of color is all connected with synchronous drive circuit 22, the input end of described synchronous drive circuit 22 is connected to the color control output end of described MCU control module 3, the public output of described MCU control module 3 and segment encode control output end correspondence are connected to common port and the segment encode control end of described black-and-white crystal plate 1,

As improvement, described color liquid crystal display control circuit also comprises: what be connected with the public output of described MCU control module 3 synchronizes change-over circuit 4, for change described MCU control module 3 public outputs output waveform, obtain an effective synchronizing clock signals, control segment encode control output end and the color control output end of described MCU control module 3 and refresh output simultaneously.

In embodiments of the present invention, increase by one be connected with the public output COM of MCU control module 3 synchronize change-over circuit 4, for change described MCU control module 3 public output COM output waveform, obtain an effective synchronizing clock signals CLK-IN(rising edge/negative edge), control segment encode control output end and the color control output end of described MCU control module 3 and refresh output simultaneously.

In the time of specific implementation, synchronous change-over circuit 4 can be divided into two large classes: a class is the circuit that is placed on MCU control module 3, as shown in Figure 2; Another kind of being built in described MCU control module 3, is also connected with public output COM, is generally by operational amplifier or analog to digital converter, obtains synchronizing clock signals CLK-IN, as shown in Figure 3 by software mode.

For segment encode color is shown evenly, with reference to Fig. 4, described color backlights 2 also comprises light guide plate 23, the bottom of described light guide plate 23 is provided with diffuse reflector 24, described color LED lamp 21 is positioned at described light guide plate 23 1 sides, the light that colored electric lamp bulb 21 sends reflects in light guide plate 23, after diffuse reflector 24 reflections, versicolor light is fully mixed, is radiated at equably on black-and-white crystal screen, mix light and emit from effective field, finally form the color content that user can see.

The black-and-white crystal plate 1 that the present embodiment provides includes common port and segment encode control end, suppose to have N common port, M segment encode control end, here N, M are natural number, the segment encode figure place that the quantity of described common port can show with black-and-white crystal plate is identical, every next common port gating, the segment encode of M the current gating of segment encode control end control demonstrates concrete content, when showing effective time, segment encode allow light to pass through, if now color backlights 2 sends colorama, on black-and-white crystal plate 1, just can demonstrate so colored content.

Take Fig. 2 as example, in the black-and-white crystal plate 1 in figure, 8 of common ports, are respectively COM0 ~ COM7, and segment encode control end is 7, is respectively SEGA ~ SEGG, and therefore, black-and-white crystal plate 1 can demonstrate 8 segment encodes, and each segment encode has 7 fields, as shown in Figure 5.Fig. 5 provides the field schematic diagram of each segment encode on black-and-white crystal plate 1, each segment encode is respectively by the corresponding gating of common port COM0 ~ COM7,7 fields of each segment encode are respectively A ~ F, in the time that the segment encode control end SEGA ~ SEGG of connection corresponding to described field is loaded with effective voltage, this field effectively shows, now can pass through light; If now color backlights 2 is luminous, described field also can demonstrate corresponding color, demonstrates different fields by control, can demonstrate corresponding colorful digital.Certainly described each segment encode can also have more or less field; such as increasing the field that represents radix point; can demonstrate like this colorful digital of mixed decimal point, obviously the protection domain of the embodiment of the present invention does not limit the number of segment encode and the number of the field that each segment encode comprises.

In the present embodiment, described color backlights 2 at least comprises a kind of color LED lamp 21 of color, and this colored electric lamp bulb can be versicolor LED lamp.The corresponding a kind of color of each COM common port backlight, color backlight is synthetic according to the principle of true color (RGB).The performance of MCU control module 3 has determined the quantity of displayable backlight color, and take the LED lamp of 3 kinds of colors as example, minimum can show 8 kinds of color (RGB 1:1: 1=2 ³=8) that, performance is good can be 32768 kinds of (RGB 5:5:5=2 ¹⁵=32768) and 16777216 kinds of (RGB 8:8:8=2 ²⁴=16777216), or even more color.That is, suppose to have the colored electric lamp bulb of X kind color, luminous or extinguish according to controlling each color LED lamp so, have at least 2 ^xplant color combination, the segment encode on black-and-white crystal plate just can have 2 ^xplant the selection that color shows.In order to reduce cost, it is enough that common segment encode can demonstrate 8 kinds of colors, need the colored electric lamp bulb of three kinds of colors, suppose to be respectively red light, green light and blue lamp, the color control output end of corresponding MCU control module 3 is just " LED-RED-OUT ", " LED-GREEN-OUT " and " LED-BLUE-OUT ", under the definite condition of the luminous intensity of the bulb of every kind of color, 8 kinds of colors output combinations of color backlights output are also just decided, such as being respectively white, red, green, blue, Huang, pink, black, azure.

Can find out from foregoing description, public output COM and segment encode control output end SEG that described control module 3 needs except having black-and-white crystal plate 1, also need 1 synchronous clock input pin CLK_IN and 3 output pins (LED-RED-OUT, LED-GREEN-OUT and LED-BLUE-OUT) for controlling color backlights 2.

In the time of specific implementation, the structure of the synchronous drive circuit 22 in color backlights 2 can be as shown in Figure 6: with the color LED lamp 21(of every kind of color be red light here, green light and blue lamp) corresponding synchronous drive circuit 22, comprise respectively divider resistance R1, R2, R3 and NPN type triode, the base stage of NPN type triode meets respectively the color control output end LED-RED-OUT of described MCU control module 3, LED-GREEN-OUT and LED-BLUE-OUT, the collector of triode passes through respectively red LED, green LED, blue led and divider resistance R1, R2, R3 meets operating voltage VCC, all ground connection of emitter of NPN type triode T.Adjusting divider resistance Ry(is R1, R2 and R3 here) size can adjust the light intensity of corresponding color LED lamp, the ON time of color LED lamp is controlled by LED-RED-OUT, LED-GREEN-OUT and LED-BLUE-OUT.

In color liquid crystal display control circuit provided by the invention, mainly the output characteristics of utilizing the public output COM of MCU control module: the N of MCU control module public output COM is effective in turn, order be T0 → T1 → T2 → ... → Tn-1 → T0, and effective time, T was identical.So, know T and beginning and ending time of one of them COM effective time, just can infer the beginning and ending time of next COM.For example, know effective start time of COM1, after T second, COM2 starts effectively so, and then, after T second, COM3 starts effectively; Or known effective end time of COM0, after T second, COM1 effectively finishes so, then, after T second, COM2 effectively finishes.The significant instant of all COM can be calculated out.

Below by several concrete for changing the synchronous change-over circuit 4 of output waveform of MCU control module 3 public output COM, the principle of work of color liquid crystal display control circuit provided by the invention is carried out to brief description.

Fig. 7 is the first exemplary circuit structural drawing of synchronous change-over circuit 22, comprise comparer A and B, the normal phase input end of described comparer A connects the first comparative voltage, the inverting input of described comparer B connects the second comparative voltage, the normal phase input end of the inverting input of described comparer A and comparer B is connected to the public output COM of described MCU control module 3, the output terminal of described two comparer A, B meets the synchronous clock input end CLK-IN of rear output synchronizing clock signals to described MCU control module 3 altogether, is connected to operating voltage by pull-up resistor Rx simultaneously.

Fig. 8 is the second exemplary circuit structural drawing of synchronous change-over circuit 22, comprise comparer A, the normal phase input end of described comparer A connects the first comparative voltage, inverting input is connected to the public output COM of described MCU control module 3, the output terminal output synchronizing clock signals of described comparer A is to the synchronous clock input end CLK-IN of described MCU control module 3, and the output terminal of comparer A is connected to operating voltage by pull-up resistor Rx simultaneously.

Fig. 9 is the third exemplary circuit structural drawing of synchronous change-over circuit 22, comprise comparer A, the inverting input of described comparer A connects the second comparative voltage, normal phase input end is connected to the public output COM of described MCU control module 3, the output terminal output synchronizing clock signals of described comparer A is to the synchronous clock input end CLK-IN of described MCU control module 3, and the output terminal of comparer A is connected to operating voltage by pull-up resistor Rx simultaneously.

With reference to Fig. 7-Fig. 9, although it is different to form the components and parts of synchronous change-over circuit 22, the comparative voltage of input is also different, but effect is all by the output waveform of the public output COM of conversion MCU control module 3, obtain an effective synchronizing clock signals CLK_IN(rising edge/negative edge), as shown in figure 10.Particularly, the synchronous change-over circuit 22 that above-mentioned Fig. 7-Fig. 9 provides, the transformation result of the public output COM7 to MCU control module 3 is as shown in following table one:

Table one

The effective time of CLK IN	Start	Middle	Finish
				Fig. 7	Negative edge	/	Rising edge
Fig. 8	Negative edge	Rising edge	/
				Fig. 9	/	Negative edge	Rising edge

Concerning MCU control module, synchronizing clock signals is to select rising edge or negative edge to be all fine, and key is the method for the whole display timing generator of the significant instant of CLK_IN in T7 and the anti-T0---T7 of pushing away.Concerning MCU control module, synchronizing clock signals CLK_IN has 3 kinds in the sequential of T7: beginning, middle, end.As shown in following table two:

Table two

Take the synchronous change-over circuit 22 shown in Fig. 7 as example, when backlight comprises 3 backlights, respectively: when red LED/green LED/blue led, adopt said method can extrapolate the backlight sequential that refreshes.Its color that can show is as following table three:

Table three

Effectively common port	Display segment code pattern	Red backlight	Green colored backlights lamp	Blue backlight	Pattern color
						COM0	“0”	ON	ON	ON	White
COM1	“1”	OFF	OFF	OFF	Black
						COM2	“2”	ON	OFF	OFF	Red
COM3	“3”	OFF	ON	OFF	Green
						COM4	“4”	OFF	OFF	ON	Blue
COM5	“5”	OFF	ON	ON	Azure
						COM6	“6”	ON	OFF	ON	Pink
COM7	“7”	ON	ON	OFF	Yellow

To indicate especially, because black is light tight, so do not show.

In the time adopting synchronous drive circuit as shown in Figure 6,3 output pins are controlled respectively switch situations red in backlight, green, blue 3 LED lamps simultaneously, and the variation of color backlight as shown in figure 11.Synchronization only has 1 COM effective, and 8 COM are effective in turn.In the time that some COM are effective, corresponding liquid crystal segment encode demonstration is determined by SEG.For example COM1 is effective, SEGB=1, and SEGC=1, other SEG is 0, liquid crystal display numeral " 1 ".And the color of liquid crystal is decided by the color LED lamp in backlight, corresponding LED-RED-OUT, LED-GREEN-OUT, LED-BLUE-OUT determine whether corresponding LED lights, for example: in the time that COM2 is effective, LED-RED-OUT=1, shows red " 2 "; In the time that COM3 is effective, LED-GREEN-OUT=1, shows green " 3 "; In like manner, in the time that COM5 is effective, LED-GREEN-OUT=1 and LED-BLUE-OUT=1, green LED lamp and blue led lamp are lighted simultaneously, show azure " 5 ".

Because the vision of eye has stop effect, so what see is not that independent 0(is white), 1(is black) etc. image, a but figure as last in Fig. 9: 0(is white) 1(is black) 2(is red) 3(is green) 4(indigo plant) 5(is azure) 6(is pink) 7(Huang) time shows.

In addition, it should be noted that: identical hardware circuit, by adjusting the ON time of backlight, can realize different color displays.Be for example peach demonstration equally, but adjust the ON time of backlight, make the ON time of red LED lamp and blue led lamp into different proportion, can present several different pink.

On the other hand, the voltage of the different corresponding invalidatings of display mode also can be different, and Figure 12 is exactly the another kind of synchronizing signal conversion timing sequence figure of synchronous change-over circuit, i.e. the another kind of output waveform of MCU control module public output COM.To same waveform, comparative voltage is not unique; For the output waveform of different COM, deviser can suitably adjust comparative voltage.The drive form of several comparative voltages that the present invention includes but be not limited to occur in accompanying drawing to black-and-white crystal plate, as long as effective voltage and dead voltage can be exported in public output COM and the color control output end of MCU control module, make black-and-white crystal plate can show corresponding contents.In addition, as another kind of embodiment, the present embodiment provides a kind of air conditioner, this air conditioner comprises described color liquid crystal display control circuit, on the display interface of air conditioner, can demonstrate the content of multiple color, compared with the air conditioner of the color liquid crystal managing chip special with existing employing, reduce the production cost of air conditioner.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, although the present invention has been carried out to more detailed explanation with reference to previous embodiment, for a person skilled in the art, its technical scheme that still can record aforementioned each embodiment is modified or part technical characterictic is wherein equal to replacement.All any modifications of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Claims

1. a color liquid crystal display control circuit, comprise black-and-white crystal plate (1), be located at the color backlights (2) of described black-and-white crystal plate (1) bottom and drive described black-and-white crystal plate (1) and the MCU control module (3) of color backlights (2), described color backlights (2) at least comprises a kind of color LED lamp (21) of color, the color LED lamp (21) of described every kind of color is all connected to the color control output end of described MCU control module (3) by synchronous drive circuit (22), the public output of described MCU control module (3) and segment encode control output end correspondence are connected to common port and the segment encode control end of described black-and-white crystal plate (1), it is characterized in that, described color liquid crystal display control circuit also comprises: what be connected with the public output of described MCU control module (3) synchronizes change-over circuit (4), be used for changing the output waveform of described MCU control module (3) public output, obtain synchronizing clock signals, control segment encode control output end and the color control output end of described MCU control module (3) and refresh output simultaneously.

2. color liquid crystal display control circuit as claimed in claim 1, it is characterized in that, described synchronous change-over circuit (4) comprises two comparer (A, B), the normal phase input end of described comparer A connects the first comparative voltage, the inverting input of described comparer B connects the second comparative voltage, the normal phase input end of the inverting input of described comparer A and comparer B is connected to the public output of described MCU control module (3), described two comparer (A, B) output terminal connects the synchronous clock input end of rear output synchronizing clock signals to described MCU control module (3) altogether, be connected to operating voltage by pull-up resistor Rx simultaneously.

3. color liquid crystal display control circuit as claimed in claim 1, it is characterized in that, described synchronous change-over circuit (4) comprises comparer A, the normal phase input end of described comparer A connects the first comparative voltage, inverting input is connected to the public output of described MCU control module (3), the output terminal output synchronizing clock signals of described comparer A, to the synchronous clock input end of described MCU control module (3), is connected to operating voltage by pull-up resistor Rx simultaneously.

4. color liquid crystal display control circuit as claimed in claim 1, it is characterized in that, described synchronous change-over circuit (4) comprises comparer A, the inverting input of described comparer A connects the second comparative voltage, normal phase input end is connected to the public output of described MCU control module (3), the output terminal output synchronizing clock signals of described comparer A, to the synchronous clock input end of described MCU control module (3), is connected to operating voltage by pull-up resistor Rx simultaneously.

5. color liquid crystal display control circuit as claimed in claim 1, is characterized in that, described synchronous change-over circuit (4) is built in described MCU control module (3), comprises operational amplifier or analog to digital converter.

6. color liquid crystal display control circuit as claimed in claim 1, is characterized in that, described color LED lamp (21) comprises red LED lamp, green LED lamp and blue led lamp.

7. color liquid crystal display control circuit as claimed in claim 6, it is characterized in that, the corresponding synchronous drive circuit (22) of color LED lamp (21) described and every kind of color all comprises divider resistance Ry and NPN type triode, the base stage of described NPN type triode connects the color control output end of described MCU control module (3), the collector of described NPN type triode connects operating voltage by described color LED lamp (21) and divider resistance Ry successively, the grounded emitter of described NPN type triode.

8. an air conditioner, is characterized in that, described air conditioner comprises the color liquid crystal display control circuit as described in claim 1-7 any one.