CN1178429A - Control circuits of fluorescent display tube - Google Patents
Control circuits of fluorescent display tube Download PDFInfo
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- CN1178429A CN1178429A CN97102500A CN97102500A CN1178429A CN 1178429 A CN1178429 A CN 1178429A CN 97102500 A CN97102500 A CN 97102500A CN 97102500 A CN97102500 A CN 97102500A CN 1178429 A CN1178429 A CN 1178429A
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- luminance signal
- display tube
- fluorescent display
- brightness
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Abstract
The present invention privides a fluorescent display tube control circuit which can optionally switch the lightness of individual segments. A display RAM 12 contains display data area 13 for storing display data for discriminating between a display state and a nondisply state of the segments and a gradation data area 14 for storing gradation data on the lightness when a fluorescent display tube illuminates. A luminance signal generation part 15 generates a luminance signal A and a luminance signal B. A selector part 18 selects one of the two luminance signals according to the gradation data, and generates a segment signal driving the fluorescent display tube from the selected luminance signal and display data and outputs it.
Description
The present invention relates to make fluorescent display tube to carry out the control circuits of fluorescent display tube that gray scale shows by section.
Fig. 7 is the structure chart of existing control circuits of fluorescent display tube.Among the figure, 1 is 8 bit digital display unit, the 2nd, the numeral that constitutes by each section fluorescent display tube, the 3rd, drive the control circuits of fluorescent display tube of numeric display unit 1 in the dynamic driving mode, the 4th, video RAM (RAM), this video RAM (RAM) will be stored in each zone of each section from the video data that central processing unit (CPU) 5 receives by main data bus 6, whether above-mentioned video data lights the data of electron ray indicator tube for expression, it is set at " 1 " when lighting fluorescent display tube, be set at when not lighting electron ray indicator tube " 0 ".The 7th, the luminance signal generating unit, this luminance signal generating unit is lighted the luminance signal of fluorescent display tube and with its output in each stipulated time, the 8th, control unit, this control unit is the reading displayed data from display random access memory 4, according to this video data with by the luminance signal of luminance signal generating unit 7 inputs the segment signal of each section is exported, the 9th, the segment signal generating unit, this segment signal generating unit is stored in the segment signal of control unit 8 inputs among the regional 9a～9g of each section, and according to the control signal of control unit 8 segment signal of storage is exported to fluorescent display tube.
Fig. 8 is the oscillogram of expression by the digital signal that signal took place in the luminance signal generating unit, and Fig. 9 amplifies the oscillogram that shows for the oscillogram of the segment signal of each section of the corresponding output with this digital signal of expression and with a segment signal.
In addition, can rewrite the change that the data in the video RAM 4 show by main data bus 6 by the instruction of sending according to central processing unit 5.
Be that example describes with control unit 8 according to the video data of each section and the process of luminance signal generation segment signal below.
For example, as shown in Figure 7, when the 1st bit representation " 1 " of numeric display unit 1, the video data that is stored in section (1) in the video RAM 4 and section (2) is for " 1 ", and the video data of other section (3)～section (7) is " 0 ".Therefore, because section (1) shown in Figure 9 and section (2), take place by calculating the logic product of these video datas and luminance signal in control unit 8 is that " H (high level) ", other section (3)～section (7) are the segment signal of " L (low level) ".
In addition, when the 2nd bit representation " 2 ", the video data that is stored in section (1) in the video RAM 4, (3), (4), (6) and (7) is " 1 ", and the video data that other section (2) reaches (5) is " 0 ".Therefore, control unit 8 is by calculating the logic product of these video datas and luminance signal, section (1) shown in Figure 9, (3), (4), (6) and (7) take place is " H ", other section (2) reaches segment signal that (5) are " L ".After, by mode segment occurred signal same as described above, till the 8th.
Have again, in order to adjust the display brightness of fluorescent display tube, and prevent to show that segment signal is provided with the shut-in time as shown in Figure 9 to other seepage.This segment signal only digital signal be " H " one digit time t
dDuring effectively.Fluorescent display tube one digit time t
dDuring only be t turn-on time of " H " at segment signal
OnDuring light, and be the shut-in time t of " L " at segment signal
OffDuring extinguish.Therefore, duty ratio D
uBe expressed as with above-mentioned repetition period T: D
u=t
On/ T.If conditions such as supply voltage that is adopted or electric current are identical, then the brightness of fluorescent display tube and duty ratio D
uProportional and since one digit time t
dBe the value that calculates except that repetition period T with constant, so the brightness of fluorescent display tube and the duty ratio d of segment signal are d=t
On/ t
dProportional.
Because existing control circuits of fluorescent display tube constitutes in a manner described, so the brightness of fluorescent display tube all unification is the value by the unique decision of duty ratio, in order to adjust brightness, even change duty ratio, can not change whole sections brightness together, just there are the problems such as brightness that can not change each section arbitrarily in this.
The present invention proposes for addressing the above problem, and its purpose is to provide a kind of control circuits of fluorescent display tube that can change each section brightness arbitrarily.
Relevant a first aspect of the present invention, control circuits of fluorescent display tube is by this luminance signal generating unit generation and export a plurality of luminance signals, be stored in video data and gradation data in the video RAM by control unit input, and with they export to each the section, by selected cell input video data and gradation data, simultaneously, import the given a plurality of luminance signals of above-mentioned luminance signal generating unit, determine one of them luminance signal according to above-mentioned gradation data, when lighting fluorescent display tube, the luminance signal of determining is just now exported to above-mentioned fluorescent display tube according to above-mentioned video data.
Relevant a second aspect of the present invention, the segment signal generating unit of control circuits of fluorescent display tube is by the counter input and count the count value that a digit time, register provided, the count value of coincident circuit in counter be stored in brightness register in count value when consistent, output and the corresponding luminance signal of this count value.
Relevant a third aspect of the present invention, the segment signal generating unit of control circuits of fluorescent display tube utilizes a plurality of coincident circuits to be connected with the brightness register of the different count values of storage respectively, exports and be stored in the corresponding luminance signal of count value in these brightness register.
Fig. 1 is the structure chart of the control circuits of fluorescent display tube of the present invention the 1st embodiment;
Fig. 2 is the structure chart of the luminance signal generating unit of the control circuits of fluorescent display tube of the present invention the 1st embodiment;
Fig. 3 is from the luminance signal A of the luminance signal generating unit output of the present invention the 1st embodiment and the oscillogram of luminance signal B;
Fig. 4 is the structure chart of the selected cell of the control circuits of fluorescent display tube of the present invention the 1st embodiment;
Fig. 5 is the operating sequence flow chart of the control circuits of fluorescent display tube of the present invention the 1st embodiment;
The structure chart of the example when Fig. 6 is used for the speed instrument of automobile for the control circuits of fluorescent display tube of the present invention the 2nd embodiment;
Fig. 7 is existing control circuits of fluorescent display tube structure chart;
Fig. 8 is the oscillogram of the digital signal that takes place in the segment signal generating unit;
Fig. 9 amplifies the oscillogram that shows for the segment signal oscillogram of each section of exporting accordingly with the digital signal of Fig. 8 and with a segment signal.
Below one embodiment of the present of invention are described.
Fig. 1 is the structure chart of the control circuits of fluorescent display tube of the present invention the 1st embodiment, among the figure, 1 is 8 bit digital display unit (fluorescent display tube), the 2nd, the numeral that constitutes by each section, the 11st, drive the control circuits of fluorescent display tube of numeric display unit 1 by the dynamic driving mode, it can switch the brightness of each section arbitrarily.The 12nd, the video RAM of storage gradation data, these data are used to select the video data and the fluorescent display tube luminance signal that receive from central processing unit 5 by main data bus, and the 13rd, (" 0 " expression is not lighted for the video data of storing each fluorescent display tube is located in the video RAM 12 one; " 1 " expression is lighted) the video data district, such as in present embodiment 1, owing to be 87 piece of digital display unit 1, so, the zone that guarantee 56 bits.The 14th, be located at (" 0 " expression luminance signal A in the video RAM 12 for the gradation data of storing each fluorescent display tube; " 1 " expression luminance signal B) gradation data district, the zone that equally also will guarantee 56 bits.
The 15th, the luminance signal generating unit, occur in one digit time t
dMake t turn-on time of segment signal during this time
OnThe different i.e. different luminance signal A (bright demonstration) and luminance signal (show slinkingly and the show) B of brightness of section.The 16th, control is from the designation data of video RAM 12 input and the gradation data control unit to the output timing of local data bus 17.The 18th, have selected cell with each corresponding gray scale segment signal generating unit 19 in section (1)～(7), this each gray scale segment signal generating unit 19 is asked for the video data and luminance signal A that selects according to gradation data or the logic product of luminance signal B by local data bus 17 inputs, when video data is " 1 ", luminance signal A or luminance signal B are outputed to each section of numeric display unit 1.
Fig. 2 is the structure chart of the luminance signal generating unit of the control circuits of fluorescent display tube of the present invention the 1st embodiment, among the figure, 21 be one digit time register, store predetermined t one digit time
dCount value, the 22nd, finish from the counter of the count value of digit time register 21 inputs according to counting source such as internal clockings, when reaching regulation t one digit time
dCount value the time, just be reset to 0.The 23rd, t turn-on time of the segment signal of store predetermined luminance signal A
OnThe register A (brightness register) of count value, the 24th, often relatively the count value of counter 22 with from the count value of register A23 input and moment that both are consistent coincident circuit A (coincident circuit) as triggered time output luminance signal A.The 25th, t turn-on time of the segment signal of store predetermined luminance signal B
OnThe register B (brightness register) of count value, the 26th, often relatively the count value of counter 22 with from the count value of register B25 input and moment that both are consistent coincident circuit B (coincident circuit) as triggered time output luminance signal B.
Fig. 3 is from the luminance signal A of the luminance signal generating unit output of the present invention the 1st embodiment and the oscillogram of luminance signal B, in Fig. 3 (a), because luminance signal A has t
1～t
dT turn-on time
On, luminance signal B has t
2～t
dT turn-on time
OnSo,, section is shown for showing slinkingly when being lighted by luminance signal B lighted the Shi Weiliang demonstration by luminance signal A.
In addition, Fig. 3 (b) represents the luminance signal B ' with the additive method generation.This luminance signal B ' is corresponding with the luminance signal B of Fig. 3 (a), at moment t
1, t
2With one digit time t
dDuring trisection, no matter fluorescent display tube is to drive by luminance signal B or by luminance signal B ', all becomes to have showing slinkingly of same brightness and show.Luminance signal B ' can adopt luminance signal A and moment t
2Take place.
Fig. 4 is the structure chart of the selected cell of the control circuits of fluorescent display tube of the present invention the 1st embodiment, among the figure, the 31st, input luminance signal A and luminance signal B also select and export one of them multiplexer according to gradation data, when gradation data is " 0 ", just select luminance signal A, when gradation data is " 1 ", just select luminance signal B.The 32nd, ask for video data with from the logic product of the luminance signal A of multiplexer 31 output or luminance signal B and at video data some "AND" circuits output luminance signal A or the luminance signal B during for " 1 ".
Below operation is described.
Fig. 5 is the operating sequence flow chart of the control circuits of fluorescent display tube of the present invention the 1st embodiment.Below, as display unit use 87 sections formations shown in Figure 1 numeric display unit 1, carry out bright demonstration and show slinkingly showing that the situation that two gray scales show describes as example with fluorescent display tube.At first, control unit 16 is when receiving the indication of the digital idsplay order that central processing unit 5 provides, be 1 (ST1) just, luminance signal A and the luminance signal B that luminance signal generating unit 15 takes place exported to selected cell 18 (ST2) by local data bus 17 with variable m assignment.Afterwards, control unit 16 m position section gradation data 7 bits that will be stored in section video data 7 bits in the m position in video data district 13 and be stored in gradation data district 14 output to (ST3) in the selected cell 18.
Select luminance signal A or luminance signal B (ST4) by selected cell 18 according to gradation data, whether judge that according to video data corresponding section with the m position is lighted (ST5).When the result who judges is when the section fluorescent display tube is lighted, selected cell 18 is lighted the fluorescent display tube (ST6) of m position section n just to the section output luminance signal A or the luminance signal B of the bright object in m site that becomes numeric display unit 1 by the brightness of luminance signal A or luminance signal B.Whether afterwards, for handling the fluorescent display tube of next section of m position is lighted, control unit 16 is m+1 (ST7) with the m assignment.
Then, handle in order to judge whether whole sections to the m position, control unit 16 is carried out m≤8 and is handled (ST8), when whole sections not being handled, just forwards ST2 to.On the other hand, when whole sections of m position are handled, just judge whether to proceed to show and handle (ST9), proceed to show when handling, just forward ST1 to, do not proceed to show when handling, promptly come to an end.
In embodiment 1, fluorescent display tube is carried out bright indication and infers the situation that two gray scales shown show control circuits of fluorescent display tube 11 has been described, but be not limited to above-mentioned situation, control circuits of fluorescent display tube 11 can make fluorescent display tube show by grey arbitrarily.But when gray scale increased, gradation data also increased, so, must strengthen video RAM 12 gradation data district 14.In addition, when gray scale number increases, the luminance signal more than 3 kinds must take place, so the timing number when luminance signal takes place also increases.
As described, according to present embodiment 1, in the control circuits of fluorescent display tube of the demonstration of controlling the fluorescent display tube that constitutes section, because multiple luminance signal takes place, one of selection overlaps onto on the video data from these signals, so the brightness of switching section arbitrarily.Therefore, by the brightness difference that makes fluorescent display tube every 3, can read numeral at an easy rate.
The structure chart of the example when Fig. 6 is used for the speed instrument of automobile for the control circuits of fluorescent display tube of the present invention the 2nd embodiment.8 bit digital display unit 1 have been described in above-mentioned the 1st embodiment, still, should be shown in the 2nd embodiment like that, fluorescent display tube also can constitute speed instrument.Among the figure, speed instrument is made of the section of expression " 0 "～" 180 ", and wherein the Duan Weiliang of the centre of from " 0 " to " 40 " and " 60 " shows, and the section of " 60 "～" 180 " is shown for showing slinkingly.In this speed instrument, " 60 "～" 180 " also show, become full scale and show, are " 50 " thereby just can discern current speed at a glance.Therefore, if use this speed instrument, the speed when grasping night easily and walking, thus can alleviate driver's burden.
Mode as described, relevant a first aspect of the present invention, utilize the generation of luminance signal generating unit and export a plurality of luminance signals, utilize control unit input to be stored in video data and gradation data in the video RAM, and they are exported to each section respectively, utilize selected cell input video data and gradation data, a plurality of luminance signals that while input luminance signal generating unit provides, determine a certain luminance signal according to gradation data afterwards, when lighting fluorescent display tube according to video data, just above-mentioned definite luminance signal is exported to fluorescent display tube, so, can switch brightness arbitrarily to each section, thereby can improve the expressive force of display unit.
Relevant a second aspect of the present invention, the segment signal generating unit utilizes counter from digit time register input and counting count value, according to coincident circuit, when the count value of counter is consistent with count value in being stored in brightness register, just output and the corresponding luminance signal of this count value, so, can switch brightness arbitrarily to each section, thereby can improve the expressive force of display unit.
Relevant a third aspect of the present invention, the segment signal generating unit is connected with the brightness register of storing the count value that has nothing in common with each other owing to a plurality of coincident circuits respectively, the corresponding luminance signal of count value of storing in output and these brightness register, so, can switch the brightness of many gray scales arbitrarily to each section, thereby can further improve the expressive force of display unit.
Claims (3)
1. control circuits of fluorescent display tube, it is characterized in that, comprise the luminance signal generating unit, video RAM, control unit and selected cell, generation of luminance signal generating unit and output make the different a plurality of luminance signals of section brightness of fluorescent display tube, the gradation data that the video RAM storage determines whether to light each video data of above-mentioned section and selects above-mentioned luminance signal, the control unit input is stored in video data and the described gradation data in the above-mentioned video RAM, and output it to each above-mentioned section, selected cell is in the above-mentioned video data and gradation data of above-mentioned each fluorescent display tube that this control unit of input provides, import a plurality of luminance signals that above-mentioned luminance signal generating unit provides, and determine one of them luminance signal according to above-mentioned gradation data, when lighting above-mentioned section, above-mentioned definite luminance signal is exported to above-mentioned fluorescent display tube according to above-mentioned video data.
2. control circuits of fluorescent display tube according to claim 1, it is characterized in that, above-mentioned segment signal generating unit comprise one digit time register, counter, brightness register and coincident circuit, the one register-stored digit time count value suitable with the fluorescent display tube high-high brightness, counter is from this digit time register input and counting count value, the brightness register storage is less than the count value suitable with the high-high brightness of above-mentioned fluorescent display tube, coincident circuit when the count value of above-mentioned counter is consistent with count value in being stored in above-mentioned brightness register, the output luminance signal suitable just with this count value.
3. control circuits of fluorescent display tube according to claim 1, it is characterized in that, above-mentioned segment signal generating unit comprises a plurality of brightness register and a plurality of coincident circuit, a plurality of brightness are deposited and are stored mutually different count value respectively, a plurality of coincident circuits link to each other with above-mentioned a plurality of brightness register respectively, and export and be stored in the suitable luminance signal of count value in above-mentioned a plurality of brightness register.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97102500A CN1178429A (en) | 1996-10-01 | 1997-02-24 | Control circuits of fluorescent display tube |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP260661/96 | 1996-10-01 | ||
| CN97102500A CN1178429A (en) | 1996-10-01 | 1997-02-24 | Control circuits of fluorescent display tube |
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| Publication Number | Publication Date |
|---|---|
| CN1178429A true CN1178429A (en) | 1998-04-08 |
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ID=5166305
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97102500A Pending CN1178429A (en) | 1996-10-01 | 1997-02-24 | Control circuits of fluorescent display tube |
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| Country | Link |
|---|---|
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100421139C (en) * | 2003-03-28 | 2008-09-24 | 三洋电机株式会社 | Fluorescent display tube driving circuit |
-
1997
- 1997-02-24 CN CN97102500A patent/CN1178429A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100421139C (en) * | 2003-03-28 | 2008-09-24 | 三洋电机株式会社 | Fluorescent display tube driving circuit |
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