CN1168063C

CN1168063C - Display device capable of automatically adjusting resolution

Info

Publication number: CN1168063C
Application number: CNB991010345A
Authority: CN
Inventors: 吴宗训
Original assignee: BenQ Corp
Current assignee: BenQ Corp
Priority date: 1999-01-08
Filing date: 1999-01-08
Publication date: 2004-09-22
Anticipated expiration: 2019-01-08
Also published as: CN1260558A

Abstract

A display device capable of automatically adjusting resolution ratio displays screen picture signals transmitted from a computer. The display device comprises a display screen, a display image, a display circuit, a first counting circuit and a control circuit. The display circuit has a phase locked loop for generating sampling clock pulses. The first counting circuit counts the number of image signals, i.e., the number of horizontal lines. The control circuit adjusts the output of the phase-locked loop according to the number of the horizontal lines, so that the display circuit samples each image signal according to the sampling clock pulse generated by the phase-locked loop.

Description

Can adjust the display device of resolution automatically

Technical field

The present invention relates to a kind of display device, particularly relate to a kind of display device that can adjust resolution automatically.

Background technology

Display device is an important device commonly used, and the screen-picture signal that is used for computer is transmitted is converted into image frame, user thereby can read and use data in the computer.Along with the progress of science and technology, the display screen of display device gradually by in the past negative electrode kinescope progress to display panels (liquid crystal display panel) and projection-type display screen.No matter be any display screen, display device must can provide various resolution, to meet the different demand of user.Presenting of different resolution depends on how display device handles the screen-picture signal that computer transmits, if disposal route is perfect inadequately, the user often must be bothered in the operation by the visual display device of adjusting very much.Therefore, how the next signal of computer transmission is done suitable processing and research and develop important problem of display device now automatically to adjust resolution, to have become.

See also Fig. 1.Fig. 1 is the synoptic diagram of existing display device 12 accepted screen picture signals.Existing display device 12 is to see through a cable of being made up of several signal wires to receive the screen-picture signal that is transmitted by computer 10, and include horizontal-drive signal 14, vertical synchronizing signal 15 and picture signal 16 in the screen-picture signal, these signals are then transmitted by different signal wires respectively, display device 12 just can demonstrate image frame after receiving these signals and being handled.

See also Fig. 2, Fig. 2 is the image segmentation synoptic diagram of conventional images scanning display frame 21.With resolution 800 * 600 is example, when display device 12 detects horizontal-drive signal 14 and vertical synchronizing signal 15, and to see through the cognitive resolution requirements up till now of tabling look-up be 800 * 600 o'clock, expression just needs image scanning display frame 21 is divided into vertical direction totally 600 horizontal scanning lines, and on every horizontal scanning line 800 lattices is arranged.Display device 12 can be sent pixel (pixel) in regular turn according to these lattices and show an image frame, at first by the 1st lattice to the 800 lattice of article one horizontal scanning line 20, follow the 1st lattice to the 800 lattice by second horizontal scanning line 22, send pixel lattice one lattice like this, up to the 800th lattice of the 600th horizontal scanning line 24, and then begin to send pixel from article one horizontal scanning line the 1st lattice circularly and show next image frame.

See also Fig. 3.Fig. 3 is the sequential chart of screen-picture signal shown in Figure 1, and VS, HS and Video represent vertical synchronizing signal 15, horizontal-drive signal 14 and the signal of picture signal 16 on the time T axle in regular turn among the figure.Display device 12 is received new image frame of a vertical synchronizing signal 15 expression beginnings each time, and the picture signal of therefore being received after the time t0 of a vertical synchronizing signal 15 of beginning 16 can be shown in regular turn by the 1st row beginning of image scanning display frame 21.And new horizontal scanning line of each horizontal-drive signal 14 expressions begins, and therefore the picture signal of being received after the time t1 of a horizontal-drive signal 14 of beginning 16 is that next line by image scanning display frame 21 begins to show in regular turn.If resolution is 800 * 600 o'clock, shown in the VS and HS of Fig. 3, after vertical synchronizing signal 30, image scanning display frame 21 can be in horizontal-drive signal 32 beginnings, send 600 horizontal scanning lines since the 1st row in regular turn, do circulation again up to next vertical synchronizing signal 34.Therefore, be under 800 * 600 in resolution, if the fixed-frequency of vertical synchronizing signal 15, as 72Hz, the frequency of horizontal-drive signal 14 just should be certain value, is about 48.8kHz.

The display device of existing automatic adjustment resolution, especially the display device of LCD monitor (LCD Monitor) or projection-type projector (Projector), it is the table of comparisons of setting up one group of vertical synchronizing signal 15 frequency, horizontal-drive signal 14 frequencies and resolution, display device is calculated vertical synchronizing signal 15 frequencies and horizontal-drive signal 14 frequencies that computer is sent here, add 72Hz and 48.8kHz, learn that according to table resolution should be 800 * 600 then.If calculate and learn that vertical synchronizing signal 15 frequencies and horizontal-drive signal 14 frequencies that computer is sent here are 70Hz and 56.48kHz, then can learn that according to table resolution should be 1024 * 768.

See also Fig. 4.Fig. 4 is the sequential chart of screen-picture signal shown in Figure 1 and sampling clock pulse 40, and Pixel Clock represents sampling clock pulse 40.Under the requirement of the resolution 800 * 600, display device 12 can produce the sampling clock pulse 40 of certain frequency voluntarily, is used for each picture signal 16 is done the action of sampling, and its sampling result is deposited into a picture buffer (not shown).Sampling clock pulse 40 numbers between two horizontal-drive signals in the picture buffer are if not 800, then revise the frequency of sampling clock pulse 40 automatically, sampling clock pulse 40 numbers between two horizontal-drive signals are 800, shown in Fig. 4 HS and pixel clock, 800 just of sampling clock pulse numbers between two horizontal-drive signals 32,33, so the frequency of sampling clock pulse 40 is just fixing.The display device of LCD monitor (LCD Monitor) or projection-type projector (projector) just is shown to digitized result in the picture buffer on the display screen.

Yet, because the display card in the computer may be from different production firms, therefore the difference that vertical synchronizing signal 15 frequencies that produced and horizontal-drive signal 14 frequencies just have a little, just in case unfortunately, these two synchronous signal frequencies do not drop in the table of comparisons that pre-sets, then display device can't be learnt resolution, also can't produce correct image certainly.At this moment, just need to set artificially and adjust, comparatively trouble.

Summary of the invention

The object of the present invention is to provide a kind of display device that can adjust resolution automatically, its synchronous signal frequency that does not need to calculate computer and provide just can determine required resolution, and the frequency by adjusting sampling clock pulse is to reach the function of automatic adjustment resolution.So, just can avoid causing the mistake of image demonstration, make display device can and be dissolved in each display card because of the difference of display card.

The object of the present invention is achieved like this, a kind of display device promptly is provided, be used for showing the screen-picture signal that a computer is transmitted, include several vertical synchronizing signals and horizontal-drive signal in this screen-picture signal, and several picture signals, the shown image frame of this display device is made of several picture signals, and this display device includes: a display screen is used for showing this image frame; One display circuit is used for handling screen-picture signal that this computer transmits and it is shown on this display screen, and it includes a phaselocked loop (phase locked loop), and being used for producing can be to the time clock (piexl clock) of each picture signal sampling; One first counting circuit is used for calculating the picture signal quantity that has image between two vertical synchronizing signals, i.e. the horizontal line number; And a control circuit, be used for adjusting the output of this phaselocked loop, so that the sampling clock pulse that this display circuit is able to produce according to this phaselocked loop is done suitable sampling to each picture signal according to the horizontal line number that first counting circuit is produced.

Description of drawings

Below in conjunction with accompanying drawing, describe embodiments of the invention in detail, wherein:

Fig. 1 is the synoptic diagram of existing display device accepted screen picture signal;

Fig. 2 is the synoptic diagram of image scanning display frame image segmentation;

Fig. 3 is the sequential chart of screen-picture signal shown in Figure 1;

Fig. 4 is the sequential chart of described screen-picture signal of Fig. 1 and sampling clock pulse;

Fig. 5 is the synoptic diagram of display device accepted screen picture signal of the present invention;

Fig. 6 is the functional block diagram of display device shown in Figure 5;

Fig. 7 is the sequential chart of Fig. 5 and screen-picture signal shown in Figure 6 and image transmission signal.

Fig. 8 is the circuit diagram of first counting circuit shown in Figure 6;

Fig. 9 is the sequential chart of Fig. 5 and screen-picture signal shown in Figure 6, image transmission signal and sampling clock pulse;

Figure 10 is the circuit diagram of second counting circuit shown in Figure 6;

Figure 11 does the process flow diagram that automatic phase-locked loop is adjusted for display circuit shown in Figure 6.

Embodiment

See also Fig. 5.Fig. 5 receives the synoptic diagram of screen picture signal for display device 50 of the present invention.Display device 50 of the present invention is electrically connected with a computer 10 mutually via a cable, be used for showing the screen-picture signal that computer 10 is transmitted, and cable includes several signal wires.Include several vertical synchronizing signals 15 and several horizontal-drive signals 14 in the screen-picture signal that computer 10 is transmitted, and several picture signals 16, and vertical synchronizing signal 15, horizontal-drive signal 14 and picture signal 16 reach display device 50 by different signal wires respectively.Display device 50 shown image frames then are made of a plurality of picture signals 16.

See also Fig. 6.Fig. 6 is the functional block diagram of display device 50 shown in Figure 5.Display device 50 includes a display screen 52, be used for the display image picture, one amplifier 54, be used for picture signal 16 is converted to the image transmission signal (video active) 55 that digital circuit can be differentiated, and a display circuit 58, be used for handling screen-picture signal that computer 10 transmitted and it is shown on the display screen 52.Display circuit 58 includes a phaselocked loop (phase locked loop) 61, and being used for producing can be to the sampling clock pulse 59 of each picture signal 16 sampling.Display screen 52 can be display panels, projection-type projector screen or other display screens.

Display device 50 also includes one first counting circuit, 56, one second counting circuits 60, and a control circuit 62.First counting circuit 56 is to be used for calculating the quantity that has the picture signal of image between two vertical synchronizing signals, i.e. horizontal line number or title vertical resolution.Second counting circuit 60 be used for calculating a picture signal with image between two horizontal-drive signals and occur in, the quantity of the sampling clock pulse that phaselocked loop 61 is produced, promptly horizontal number of samples or claim horizontal resolution.62 of control circuits are to be used for adjusting the output that shows phaselocked loop 61 according to the horizontal line number that first counting circuit 56 is produced, so that display circuit 58 is able to according to the sampling clock pulse 59 that phaselocked loop 61 is produced each picture signal be done suitable sampling.Control circuit 62 also includes a storer 64, is used for storing a sampling table of comparisons 66, and has the corresponding target number of samples of various horizontal line numbers of an image frame in the sampling table of comparisons 66.Control circuit 62 can become corresponding target number of samples with the horizontal line number conversion that first counting circuit 56 is produced according to the sampling tables of comparisons 66, and the output of then adjusting phaselocked loop 61 again makes the horizontal number of samples that second counting circuit 60 produced can convergence or reach till this target number of samples.

Table 66

Vertical resolution (horizontal line number)	350	?400	?480	?600	?768	?900	?1024
Vertical resolution (horizontal line number)	350	?400	?480	?600	?768	?900	?1024	Horizontal resolution (vertical sampling number)	640	?640	?640	?800	?1024	?1152	?1280

See also table.Table is the sampling table of comparisons 66 shown in Figure 6.Because resolution is divided into 640 * 350,640 * 400,640 * 480,800 * 600,1024 * 768,1152 * 900 and 1280 * 1024 etc. generally in the VESA standard, so each vertical resolution can correspond to a kind of and only corresponds to a kind of horizontal resolution.In other words when knowing a certain specific vertical resolution of an image frame (horizontal line number), just can extrapolate its corresponding horizontal resolution (horizontal number of samples), therefore the corresponding target number of samples of various horizontal line numbers of an image frame can be set up according to this man-to-man relation, and the sampling table of comparisons 66 can be formed.

Being adjusted into 800 * 600 with resolution is example, when display device 50 is carried out the resolution adjustment, computer 10 can be sent horizontal-drive signal 14, vertical synchronizing signal 15 and the picture signal 16 of a full frame picture earlier, and these signals are sent to display device 50 as the foundation of differentiating resolution.First counting circuit 56 is understood first calculated level number of lines and obtained is 600, and control circuit 62 is 800 according to 600 the horizontal line number and the table of comparisons 66 of taking a sample with the decision of target number of samples then.60 horizontal number of samples of calculating in the present sampling clock pulse 59 of second counting circuit, if do not conform with 800 target number of samples demand, display circuit 58 just can be adjusted phaselocked loop 61 outputs wherein, then influence the sampling frequency of sampling clock pulse 59, till horizontal number of samples reaches target number of samples 800.Display circuit 58 is done suitable sampling according to resulting sampling clock pulse 59 to each picture signal, is deposited at a picture buffer (not shown), then is shown in regular turn on the display screen 52.

See also Fig. 7 and Fig. 8.Fig. 7 is the sequential chart that screen-picture signal shown in Figure 6 and image send signal, and vertical synchronizing signal (VS) 15, horizontal-drive signal (HS) 14, image send signal (videoaction) and the signal of picture signal (video) 16 on time (T) axle.Fig. 8 is the circuit diagram of first counting circuit 56 shown in Figure 6.In the screen-picture signal that is transmitted by computer 10, contain several horizontal-drive signals between time point t0, the tn of per two

vertical synchronizing signals

72,78, and each picture signal is between two horizontal-drive signals.First counting circuit 56 includes a D flip-flop (D flip-plop) 70, be used to provide the time point t1 that a kind of vertical synchronizing signal 72 first image afterwards sends signal 76 beginnings, one horizontal counter 74, be used for calculating first image and send horizontal-drive signal quantity between the time point tn before signal 76 begins to arrive to next vertical synchronizing signal 78, one first register 80, the quantity that horizontal counter when being used for reading image transmission signal calculates, one second register 82 is used for reading next vertical synchronizing signal 78 preceding first register, 80 stored quantity.Be that when a vertical synchronizing signal 72 started, D flip-flop 70 was output as electronegative potential under 800 * 600 the full frame picture in a resolution, and horizontal counter 74 can be made zero and restarted.When image sends signal 76 at the beginning, the output of D flip-flop 70 is lockable and is noble potential, the number of therefore horizontal counter 74 beginning calculated level synchronizing signals 14.Each image sends signal one and arrives, and first register 80 reads the number that present horizontal counter 74 is calculated at once.When next vertical synchronization start signal 78, second register 82 reads the number of first register 80 and exports to control circuit 62 and makes a decision.If the quantity that control circuit 62 is read is 599, learns that picture signal is 600, thereby can learn that present resolution is 800 * 600, and adjust the output of phaselocked loop 61 with this resolution according to the sampling table of comparisons 66.

See also Fig. 9 and Figure 10.Fig. 9 is the sequential chart of Fig. 5 and picture signal shown in Figure 6, image transmission signal and sampling clock pulse, and pixel clock represents sampling clock pulse.Figure 10 is the circuit diagram of second counting circuit 60 shown in Figure 6.Second counting circuit 60 includes a D flip-flop 86, be used to provide the time point t2 that a horizontal-drive signal 85 first image afterwards sends signal 88 beginnings, one sampling counter 90, be used for calculating first image and send sampling clock pulse quantity between the time point t3 before signal 88 begins to arrive to next horizontal-drive signal 92, the 3rd register 94, the quantity that sampling counter 90 calculates when being used for reading image transmission signal, one the 4th register 96 is used for reading preceding the 3rd register of a horizontal-drive signal 94 stored quantity.When horizontal-drive signal 85 started, D flip-flop 86 was output as electronegative potential, and sampling counter 90 can be made zero and restarts.When image sends signal 88 at the beginning, the output of D flip-flop 86 is lockable and is noble potential, so sampling counter 90 begins to calculate the number of sampling clock pulse 59.Each image sends signal 55 1 and arrives, and the 3rd register 94 reads the number that present sampling counter 90 is calculated at once.When next horizontal-drive signal 92 started, the 4th register 96 read the number of the 3rd register 94 and exports to display circuit 58 and makes a decision.

See also Figure 11.Figure 11 does the process flow diagram that automatic phase-locked loop is adjusted for display circuit 58 shown in Figure 6.Should be after 800 * 600 when differentiating resolution, phaselocked loop can provide a default output earlier, is then gone to read the quantity of the 4th register 94 by display circuit 58.If the quantity of display circuit 58 the 4th register 94 of reading is not for being 799, then adjust the output of phaselocked loop 61, up to the quantity of reading the 4th register 94 for being 799, this moment, the number of samples of each picture signal just was 800, meeting the demand of 800 * 600 resolution, and with correct being presented on the display screen 52 of image.

Display circuit in the display device 50 of the present invention also can be designed to a projection display circuit, become the optical imagery picture and it is projected on the display screen 52 with the screen-picture conversion of signals that computer 10 is transmitted, remainder is then all similar with above-mentioned disclosed technology.

Compare with existing display device, display device 50 of the present invention utilizes that horizontal line number and horizontal number of samples are that man-to-man relation forms the sampling table of comparisons 66 in the image frame, direct calculated level lines number and obtain correct target number of samples according to the sampling table of comparisons 66, and can adjust and present vertical resolution correct in the picture and horizontal resolution automatically.So, just can avoid causing the mistake of image demonstration, make display device can and be dissolved in the display card that variant producer produces because of the out of true of the output signal of display card own.

The above only is preferred embodiment of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to the covering scope of patent of the present invention.

Claims

1. A display device, used to display a screen image signal sent by a computer, the screen image signal includes several vertical synchronization signals and horizontal synchronization signals, and several image signals, an image displayed by the display device The screen is composed of several image signals, and it is characterized in that the display device includes:

a display screen for displaying the image frame;

A display circuit, which is used to process the screen image signal sent by the computer and display it on the display screen, which includes a phase-locked loop, which is used to generate a clock pulse that can sample each image signal;

A first counting circuit, used to count the number of image signals with images between two vertical synchronous signals, that is, the number of horizontal lines; and

A control circuit, used to adjust the output of the phase-locked loop according to the number of horizontal lines generated by the first counting circuit, so that the display circuit can make appropriate adjustments to each image signal according to the sampling clock pulse generated by the phase-locked loop sampling.

2. The display device as claimed in claim 1, characterized in that, it comprises a second counting circuit, which is used to calculate the sampling rate produced by the phase-locked loop when an image signal having an image between two horizontal synchronizing signals occurs. The number of clock pulses, that is, the number of horizontal samples, and the control circuit determines a corresponding target sample number according to the number of horizontal lines generated by the first counting circuit, and then adjusts the output of the phase-locked loop to make the second The number of horizontal samples generated by the counting circuit approaches or reaches the target sample number.

3. The display device according to claim 2, wherein the control circuit comprises a memory for storing a sampling comparison table, which stores a target sampling number corresponding to various horizontal line numbers of an image frame, and The control circuit converts the number of horizontal lines generated by the first counting circuit into a corresponding target sample number according to the sampling comparison table.

4. The display device according to claim 1, characterized in that, in the screen image signal transmitted from the computer, several horizontal synchronization signals are contained between every two vertical synchronization signals, and each image signal is located at between two horizontal sync signals.

5. The display device according to claim 4, wherein the display device is connected to the computer through a cable, and the cable includes several signal lines, and the vertical synchronous signal, horizontal synchronous signal and image signal They are respectively transmitted to the display device by different signal lines.

6. The display device as claimed in claim 1, wherein the display screen is a liquid crystal display panel.

7. The display device according to claim 1, wherein the display circuit is a projection display circuit, which is used to convert the screen image signal transmitted by the circuit into an optical image frame and project it to the display screen.

8. The display device as claimed in claim 1, further comprising a frame buffer for storing screen frame signals transmitted from the computer.