JP3501706B2 - Image display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a display screen position adjusting method in a dot matrix type image display device, and more particularly to a multi-scan type image signal to which a video signal having an unspecified standard is inputted. It is suitable for use in liquid crystal displays and liquid crystal projectors. 2. Description of the Related Art In recent years, so-called multi-scan type image display apparatuses, such as computer equipment, capable of displaying image signals having various frequencies (resolutions) have become mainstream. Incidentally, the image signals input from the outside are not all standardized single specifications, and the horizontal and vertical start positions of the image differ depending on the type (frequency) of the signal even when the resolution is the same. This means that, when the image displayable range and the number of display pixels correspond to each other as in a dot matrix type image display device, an image is lost due to a shift in the display position. Therefore, it is necessary for the image display device to have means capable of displaying an image at an accurate position corresponding to an input image signal. FIG. 5 is a block diagram showing the configuration of a conventional image display device, which comprises an A / D converter 1, an image display section driving circuit 2, an image display unit 3, a display control circuit 4, and a preset data memory 5. Is done. In this configuration, the analog video signals Ra, Ga, and Ba are converted into digital signals Rd, Gd, and Bd by the A / D converter 1 and stored in the image memory included in the configuration of the image display unit driving circuit 2. The timing of writing to the image memory is controlled by the display control circuit 4. The image display unit drive circuit 2 performs image data processing so that signals R, G, and B suitable for the image display unit 3 are obtained, and drives drive pulses of the image display unit 3 (horizontal synchronization pulse H, vertical synchronization pulse V And a pixel clock CK). In the display position adjustment of the screen in this configuration, the data is held in the preset data memory 5 as the preset value using the image position information assuming the types of signals that can be connected, and the display control circuit 4 determines the types of signals. The method is to set the corresponding preset value. Therefore, since accurate adjustments cannot be made for other signal types, measures have been taken such as providing an adjusting means so that a user can make manual adjustments. FIG. 6 is a block diagram showing a second conventional example, in which an A / D converter 1, an image display unit driving circuit 2, an image display unit 3, a display control circuit 4, and an image position detecting circuit 6 '. Consists of In this configuration, the digitally converted video signals Rd, G
d, Bd, horizontal synchronization signal Hsync, vertical synchronization signal Vs
The sync and the dot clock DCK are input. The image position detection circuit 6 'outputs video signals Rd, Gd, and Vd for the horizontal synchronization signal Hsync and the vertical synchronization signal Vsync.
The screen position is automatically adjusted by detecting the position of Bd and controlling the timing at which the display control circuit 4 writes the digital video signals Rd, Gd, and Bd to the image memory included in the image display unit driving circuit 2 based on the result. (JP-A-7-44125, JP-A-10-63234, etc.). [0005] However, in the former image display apparatus shown as a conventional example, it is not necessary to manually adjust the signal type set as a preset value. When a signal is input, the user must adjust the horizontal and vertical screen positions while watching the display screen, which not only complicates the work but also makes it difficult to make accurate adjustments. Was. In the latter conventional example, although the position adjustment can be automated, the operation speed of the image position detection circuit 6 ′ is also relatively low in consideration of the recent increase in the resolution of the display screen and the increasing input signal frequency. In addition, there is a problem that current consumption increases because the speed is increased, and a high-speed circuit device is required to realize the image position detection circuit 6 ′, resulting in an increase in cost. Further, in particular, in the case where the adjustment of the image position is performed sequentially one dot at a time, there is a problem that the adjustment of the display position takes time and the start of display is delayed. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and automatically adjusts the display position of an image displayed on a dot matrix type image display device and reduces the current consumption to reduce the cost. It is an object of the present invention to provide an image display device having means and automatic display position adjustment. SUMMARY OF THE INVENTION The present invention provides an arbitrary standard.
Image signal is input and the image is converted to dot matrix type
An image display device for displaying on an image display unit of
Write an input image signal which is the input image signal.
Having an image memory for storing and storing
Sending the stored input image signal to the image display unit
Convert to a display image signal suitable for display and
Horizontal sync signal for driving the image display unit, vertical
Drive timing signal which is a synchronization signal and a pixel clock
Image display unit driving means for generating the display image signal and
And the image display unit based on the
Display position detecting means for detecting the display position of the image on the screen
The display position detection result by the display position detection means
From the input image signal to the image display unit driving means.
Display control means for controlling the
Preset data that stores the preset data of
And a display memory, wherein the display control means includes:
The preset data corresponding to the standard of the image signal
The plurality of preset data in the preset data memory.
The image display unit driving means.
At the write timing based on the preset data,
Means for writing the input image signal,
The display position detecting means is based on the preset data.
The image written at the write timing
Stored in a memory and output from the image display unit driving means.
From the display image signal in one horizontal scanning period.
Pixel clock number H at the time when the display image signal is first input
FC and the time when the display image signal finally disappeared
And the number of pixel clocks HRC of
At the time when the display image signal between
Horizontal sync signal number VFC and the display image signal last
Detects the number of horizontal synchronization signals VRC at the time when the operation is stopped.
Means, wherein the display control means receives the input HF
C, HRC, VFC, VRC and water to the image memory
Mhs, M which are initial values of flat and vertical write timings
vs. the table output from the image display unit driving means.
Horizontal output start timing Phf vertical output of display image signal
Start timing Pvf and horizontal output end timing Phr
And the vertical output end timing Pvr, the image
The write timing of the input image signal to the memory is
When the vehicle is moving forward, the difference between the HFC and the Phf and the
Mhs and the horizontal direction to the image memory.
The write timing Mh is determined to be delayed, and
Add the difference between the VFC and the Pvf and the Mvs
Vertical writing timing to the image memory
Mv is determined to be delayed, and further to the image memory
The write timing of the input image signal is delayed
Between the Mhs and the Phr and the HRC
Decide to advance the Mh by subtracting the difference, and
Subtract the difference between Pvr and VRC from Mvs
By determining to advance the Mv at
Equal to the Mhs and the Mv equal to the Mvs
The display control means is configured to control the Mh
Is equal to the Mhs, and the Mv is the same as the Mvs.
It is noted that the display position is adjusted by making them equal.
An image display device is provided. Preferably, in the present invention, the image display section driving means includes an image memory for temporarily storing a fetched input image signal, and generates a horizontal synchronizing signal, a vertical synchronizing signal and a pixel clock as the driving timing signal. The display position detecting means detects a horizontal start position of an image to be displayed on the image display unit as the number of pixel clocks from a rise of the horizontal synchronization signal in one horizontal scanning period until the display image signal is detected. At the same time, the horizontal end position of the image is detected as the number of pixel clocks from the rise of the horizontal synchronization signal to the absence of the display image signal, and the vertical start position of the image is set to 1
The number of horizontal synchronization signals from the rise of the vertical synchronization signal to the detection of the display image signal during the vertical scanning period is detected, and the vertical end position of the image is determined by the presence of the display image signal from the rise of the vertical synchronization signal. The display position control means detects the difference between the detection result by the display position detection means and the set value of the display image signal output timing from the image display section driving means. The image display position is automatically adjusted by controlling the timing of taking the input image signal into the image memory of the image display unit driving means. Further, the display control means includes: a preset data memory in which an ideal value of a fetch timing (display image signal output timing) to the image memory according to each of a plurality of standards of the input image signal is stored in advance; Means for judging the standard of the input image signal based on the input horizontal synchronizing signal and the input vertical synchronizing signal accompanying the signal and reading out the ideal value based on the judgment result. DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of the present invention, FIG.
As shown in FIG. 1, an A / D conversion circuit 1 for converting analog image input signals Ra, Ga, Ba into digital signals Rd, Gd, Bd, and digitally converted video signals Rd, G
an image display unit driving circuit 2 that converts d and Bd into signals R, G, and B suitable for the image display unit and generates a drive timing pulse for driving the display unit 3; an image display unit 3; Digital image signals R, G, B for the image display unit produced by the
Horizontal synchronization signal H, vertical synchronization signal V and pixel clock C
A display position detection circuit 6 for inputting K to detect a horizontal start and end position and a vertical start and end position of a display image;
A digital signal writing timing to an image memory included in the image display unit driving circuit 2 based on the display position information detected by the display position detecting circuit 6 and comprising a display control circuit 4 and a preset data memory 5. Is controlled by the display control circuit 4 to automatically adjust the display image position. The display position detecting circuit 6 is arranged at the subsequent stage of the image display section driving circuit 2 so that
Even when the frequency of the input image signal is high, the display position detection circuit 6 is kept within the driving speed of the image display unit 3, so that the current consumption of the detection circuit 6 is suppressed and the cost is increased by using a high-speed device. It is possible to avoid. [0011] Further, by adopting a system flow in which the image display device automatically adjusts the image position immediately before the first image is displayed, a system is realized in which the user does not care about the displacement of the display screen. can do. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an image display device according to the present invention. The A / D converter 1, the image display unit driving circuit 2, the image display unit 3, the display control circuit 4, the preset data memory 5, It comprises a display position detection circuit 6. Input analog video signals Ra, G
a and Ba are dot clocks DC in the A / D converter 1.
The signal is converted into digital signals Rd, Gd, and Bd by K and input to the image display unit driving circuit 2. The image display section driving circuit 2 is configured to include an image memory, and the digitally converted video signal R
d, Gd, and Bd are temporarily stored in this image memory in accordance with the dot clock DCK, and then read out by a clock having a frequency different from that of the dot clock DCK to become signals R, G, and B suitable for the image display unit 3. Is processed as follows. Since the read timing from the image memory is fixed in view of the system configuration, the image display position in the image display unit 3 is determined by the timing at which the digital video signals Rd, Gd, Bd are written to the image memory by the dot clock DCK. That is, if the writing timing to the image memory in the horizontal direction is early, the writing starts from the timing when there is no effective image signal, so that the display position of the image output from the image display section driving circuit 2 is rightward. The display is shifted. Also, if the writing timing to the image memory is late, the writing starts from the middle of the effective image signal.
The display position of the image output from is shifted to the left. Similarly, in the vertical direction, if the writing timing to the image memory is early, the display position is shifted downward, and if it is late, the display is shifted upward. The image display section drive circuit 2 further generates drive timing pulses (horizontal synchronization pulse H, vertical synchronization pulse V, and pixel clock CK) for the image display unit 3, and drives the image display section according to these timing pulses. An image is displayed by inputting the video signal processed by the circuit 2 to the image display unit 3. The writing timing to the image memory included in the image display section driving circuit 2 is determined by the display control circuit 4.
Is controlled by The video signals R, G, B, the horizontal synchronizing signal H, the vertical synchronizing signal V, and the pixel clock CK output from the image display driving circuit 2 are input to the display position detecting circuit 6. The display position detection circuit 6 has a counter that counts the pixel clock CK from the rise of the horizontal synchronizing signal H in the horizontal direction, and as shown in FIG. 2, the pixel at the time when the video signals R, G, and B are first input. Clock C
The number K is detected as HFC, and the number of pixel clocks CK at the time when the video signal no longer exists last is detected as HRC. Further, it has a counter for counting the horizontal synchronization signal H from the rise of the vertical synchronization signal V in the vertical direction. As shown in FIG. 3, the number of horizontal synchronization signals H at the time when the video signal is first input is VFC, Is detected as VRC when the number of horizontal synchronizing signals H at the time when no longer exists. Position information HFC, HR detected by the display position detection circuit 6
C, VFC and VRC are input to the display control circuit 4,
The difference from the set value of the image output timing in the image display unit driving circuit 2 is determined. From the result, the display control circuit 4
Adjusts the display position by controlling the timing of writing to the image memory included in the image display unit driving circuit 2. For example, when there is a slight shift of about several dots as the writing timing to the image memory in the horizontal direction, the output image data from the image display unit driving circuit 2 is as shown in VIDEO of FIG. Here, Phf indicates the horizontal output start timing of the image data set in the image display unit driving circuit 2. Therefore, the difference between the horizontal position information HFC and Phf is detected in the display control circuit 4, and the display control circuit 4 sends the image data to the image memory included in the image display unit driving circuit 2 based on the adjustment flow shown in FIG. Of the digital data is controlled. When there is an extremely large deviation in the writing timing to the image memory in the horizontal direction, for example, when the total number of dots between horizontal synchronization signals is 1328, the number of display dots is 1024, and the writing timing to the image memory is 304 dots. As described above, that is, when the input image signal is shifted by a blanking period or more, the video signal output of the image display unit driving circuit 2 becomes as shown in VIDEO 'of FIG. Here, Phr indicates the horizontal output end timing of the image data set in the image display unit driving circuit 2.
Since the writing timing to the image memory is shifted by the blanking period or more, the image data output from the image display unit driving circuit 2 starts at the horizontal output start timing Phf and ends at the horizontal output end timing Phr. It will be a sandwiched shape. Therefore, even though the display position is greatly shifted, the display position information HFC and HRC detected by the display position detection circuit 6 are equal to the set timings Phf and Phr, respectively, so that accurate adjustment is impossible. Become. Therefore, the minimum required preset data (for example, VGA for each resolution,
SVGA, XGA image memory writing timing, etc.)
By preparing the preset data in the image display unit drive circuit 2 in advance by determining the type of the signal input by the display control circuit 4, such a situation where such an extreme shift occurs is avoided. Thereafter, as in the case of a slight shift, the timing of writing digital data to the image memory included in the image display unit driving circuit 2 is controlled based on the adjustment flow shown in FIG. In this embodiment, the image signals to be input to the display position detection circuit are of three systems of R, G and B, but may be simply one of R, G and B. FIG. 4 shows a system flow for adjusting the display position in the image display device according to the present invention. When the display position adjustment is started, first, in step S1, the display position detection circuit detects horizontal and vertical display position information HFC, HRC, VFC and VRC, respectively. Next, in step S2, the horizontal output start timing P of the image data from the image display unit drive circuit 2 is set.
hf and the vertical output start timing Pvf are compared with the horizontal start position HFC and the vertical start position VFC detected by the display position detection circuit 6, respectively. If the comparison results are not equal, the timing of writing digital data to the image memory included in the image display unit driving circuit 2 is advanced (if the timing of writing to the image memory is delayed, the data is read at the time of reading from the image memory). (There is no shift as a display start position because of the existence of the image data.) Then, the process proceeds to step S3, where the horizontal write timing Mh and the vertical write timing Mv to the image memory are respectively set as (1) MV = Mvs + [VFC-Pvf] (2) Here, Mhs and Mvs are initial values of horizontal and vertical write timings to the image memory, respectively. If the comparison results in step S2 are equal, the process proceeds to step S4. In step S4, the horizontal output end timing Phr and the vertical output end timing Pvr of the image data from the image display unit driving circuit 2 are compared with the horizontal end position HRC and the vertical end position VRC detected by the display position detecting circuit 6, respectively. If the comparison results are not equal, the timing of writing digital data to the image memory included in the image display unit driving circuit 2 is delayed (if the timing of writing to the image memory is advanced, the data is not read at the time of reading from the image memory). (There is no shift as the display end position because of the existence of the image), and therefore, step S5 is performed.
The horizontal write timing Mh to the image memory,
The vertical write timing Mv is given by Mh = Mhs- [Phr-HRC] (3) Mv = Mvs- [Pvr-VRC] (4) If the comparison results in step S4 are equal, the process proceeds to step S6. When the process reaches step S6, since the display position is correct, Mh = Mhs (5) Mv = Mvs (6), and the display position adjustment ends. The above-mentioned flow is performed by displaying an image of the type immediately after displaying the image immediately after the power of the image display apparatus is turned on or when the type of the input image signal changes during the screen display. By performing the operation immediately before the operation, it is possible to realize a system in which the user does not care about the displacement of the display screen. As described above, according to the present invention, the display position of the image display unit can be accurately detected by detecting the display position of the image from the image data output from the image display unit driving circuit. Becomes possible. Further, by using the result to control the timing of writing the input video signal to the image memory included in the image display unit driving circuit, it is possible to realize a good image display without any loss. Further, by arranging the display position detecting circuit after the image display section driving circuit, that is, in the driving environment of the image display unit, it is possible to reduce the operation speed of the display detecting circuit, thereby reducing the current consumption. Since the circuit can be realized by a low-speed device, the cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration of one embodiment of an image display device according to one embodiment of the present invention. FIG. 2 is a timing chart showing an example of a display position with respect to a horizontal synchronization signal. FIG. 3 is a timing chart showing an example of a display position with respect to a vertical synchronization signal. FIG. 4 is a flowchart showing a system flow of display position adjustment in the apparatus of FIG. FIG. 5 is a block diagram illustrating a conventional configuration example of an image display device. FIG. 6 is a block diagram showing a second conventional configuration example of the image display device. FIG. 7 is a timing chart showing an example of a display position with respect to a horizontal synchronization signal. [Description of Signs] 1 A / D converter 2 Image display unit drive circuit 3 Image display unit 4 Display control circuit 5 Preset data memory 6, 6 'Display position detection circuit

Continuation of the front page (56) References JP-A-10-228266 (JP, A) JP-A-8-87249 (JP, A) JP-A-11-52920 (JP, A) JP-A-11-202839 (JP, A) JP-A-2-34894 (JP, A) JP-A-6-266311 (JP, A) JP-A-2000-122624 (JP, A) JP-B-6-36143 (JP, B2) (58) Survey Field (Int.Cl. ⁷ , DB name) G09G 3/00-5/42 G02F 1/133 505-580 H04N 5/66-5/74

Claims (1)

(57) The table Shimesuru image display device to the image display unit of the dot matrix type image signal is an input to an image having a [Claims 1 Any standard, the input The input image signal which is the image signal to be written is written.
Having an image memory for storing and storing
The co Converting stored the input image signal to the display image signal suitable for display to the previous SL image display unit
Horizontal synchronizing signal for driving the images display unit, vertical
An image display unit drive means for generating a dynamic timing signal driving a synchronous signal and a pixel clock, based on the Display image signal and the drive timing signal
Display position detection means for detecting a display position of the picture image to the image image display unit, the display position detection result whether et before in the display position detection means
Writing outs the input image signal to the image display unit drive means
And Table 示制 control means for controlling the timing, preset in advance stores a plurality of preset data
And a data memory, wherein the display control means complies with the standard of the input image signal.
The corresponding preset data is stored in the preset data
Capturing from the plurality of preset data of the memory
In the image display unit driving means, the preset data
At the write timing based on the input image signal
Means for performing writing, wherein the display position detecting means is based on the preset data.
The written image at the write timing
Stored in an image memory and output from the image display unit driving means.
From the obtained display image signal in one horizontal scanning period.
Number of pixel clocks when display image signal is first input
When the HFC and the display image signal finally disappear
Detects the pixel clock number HRC of a point and performs one vertical scan
When the display image signal is first input during the period
The horizontal synchronization signal number VFC and the display image signal last exist.
Detects the number of horizontal synchronization signals VRC at the point when it no longer exists
The display control means is configured to input the HFC, HRC,
VFC, VRC, horizontal and vertical writing to the image memory
Mhs and Mvs, which are initial values of the embedding timing,
Of the display image signal output from the image display unit driving means.
Horizontal output start timing Phf Vertical output start timing
Pvf, horizontal output end timing Phr, and vertical output
From the end timing Pvr, the writing timer of the input image signal to the image memory is changed.
When the imaging is progressing, the HFC and the Phf
Of the image memo by adding the difference of
To delay the horizontal write timing Mh
And the difference between the VFC and the Pvf and the Mvs
Vertical writing to the image memory by adding
The timing Mv is determined to be delayed, and further, the writing of the input image signal to the image memory is performed.
From the Mhs when the
Advance the Mh by subtracting the difference between Phr and the HRC
And the Pvr and the M
Decided to advance the Mv by subtracting the difference from VRC
To make the Mh equal to the Mhs and
Mv is equal to the Mvs, and the display control means sets the Mh equal to the Mhs.
And by making the Mv equal to the Mvs,
An image display device characterized in that the display position is adjusted .