JPH11146222A - Device and method for driving display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive unit for optical scanning type display with which an image of satisfactory visibility can be displayed while utilizing a resonant optical scanner without overlapping images. SOLUTION: This drive unit for display has a resonant optical scanner for modulating a light source 26 through a horizontal scanner 33 and a vertical scanner 34,a memory 29 for sequentially storing image information for each horizontal scanning line, and a line control timing circuit 30 for sequentially designating the addresses of the memory 29. The image data on one horizontal scanning line are read out at a speed tice that of a source image during horizontal scanning in one direction, but is on standby during horizontal scanning in the other direction. The line control timing circuit 30 controls the address of a memory 23 so as to read only the image data on the horizontal scanning lines of odd numbers in the order of numbers during forward vertical scanning, but to read only the image data on the horizontal scanning lines of even numbers inversely to the numbers during backward vertical scanning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for driving a display device, and more particularly to a display device for forming an image by two-dimensionally scanning a light beam modulated with a video signal using an optical scanner. The present invention relates to a driving device and a method.

[0002]

2. Description of the Related Art In a display device, in order to handle input / output of an image as an electric signal, a process of decomposing a light image into a large number of pixels and converting it into a series of electric signals arranged in order, Scanning the light modulated based on the signal to form an image. This series of operations is standardized as the NTSC system in a general television. In order to display one screen on a television screen, horizontal scanning and vertical scanning are performed. The image signal used in the current television is formed using a CDD camera or the like, and the original image is subjected to two-dimensional linear scanning from the upper left to the lower right of the screen, and the brightness and the color of the pixels are electrically changed. It is processed by decomposing it into elongated line segments (scanning lines) with numbers indicated by typical strengths.

In a general television, the above scanning is performed 60 times or more per second in order to obtain a flicker-free image. When the television receiver receives this signal,
An electron beam is scanned in the scanning order to cause the phosphor to emit light in accordance with the intensity, thereby restoring an image. The electron beam is scanned from the upper left to the lower right, and when reaching the lower right, it is represented by a sawtooth wave that returns to the upper left at a stretch after temporarily setting the intensity of the electron beam to zero and leaving a certain blanking period. Repeat the exercise.

FIG. 6A shows a temporal change of a horizontal scanning signal and a period during which an image is displayed on a CRT of a conventional television receiver or the like. There is a blanking period where there is little image information at the beginning and end of the sawtooth signal, and the image signal is displayed continuously between the blanking periods. That is, an image is displayed in synchronization with the sawtooth scanning signal.

[0005]

As a light scanner, a resonance type scanner which scans in a forward direction and a reverse direction using a vibrating horizontal mirror and a vertical mirror is known. However, in a conventional image display device for displaying a television signal, the image processing circuit assumes that horizontal scanning and vertical scanning are performed in a sawtooth waveform. For this reason,
When a resonance type scanner that scans with a sine wave as shown in FIG. 6B is used for displaying an image of a television signal, an image is displayed at each end of the sine wave motion performed by the scanner, and is originally located at a different position. There is a problem that an image to be displayed is displayed at the same position. That is, in the resonance type scanner, there is a problem that an image to be displayed is like a single picture folded vertically and horizontally.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned disadvantages when a display device is driven by using a resonance type scanner, to provide an image having an original image resolution, no image overlap, and to have good visibility. An object of the present invention is to provide a driving apparatus and a driving method of an optical scanning display device capable of displaying an image.

[0007]

In order to achieve the above object, a driving apparatus for a display device according to the present invention vertically scans a light beam containing image information in a forward direction and a reverse direction by a resonance type optical scanner. In a drive device of a display device of a type that outputs an image for each horizontal scanning line, an image memory for storing image information for each horizontal scanning line in the order of the row number of the horizontal scanning line; An image information readout control circuit for reading out image information from the image memory by designating the order of each horizontal scanning line of the image memory in a different order in reverse or forward direction in correspondence with vertical scanning.

In the display device driving apparatus of the present invention, the order of each horizontal scanning line of the image memory is set to normal and reverse for the vertical scanning in the forward direction and the reverse direction, respectively. A visually good image is obtained.

Preferably, the image information readout control circuit sequentially reads out image information of horizontal scanning lines having odd line numbers in ascending order of vertical scanning in correspondence with vertical scanning in the forward direction, starting from the one with the smallest row number. The horizontal scanning lines having even row numbers are sequentially read from the one with the largest row number in correspondence with the vertical scanning. In this case, the configuration of the read control circuit is simplified.

The image information read control circuit may include a clock generation circuit for generating a first clock based on a driving frequency of a horizontal scanner, and an address of the image memory sequentially counted by counting the first clock. And a line control timing circuit that generates a second clock based on the driving frequency of the vertical scanner and controls the address of the image memory based on the second clock. The line control timing circuit outputs a reset signal for resetting the address of the image memory, an inversion signal for inverting the address of the image memory, and a thinning signal for thinning the address of the image memory corresponding to a horizontal scanning line. This is also a preferred embodiment of the present invention.

It is preferable that the image information reading control circuit reverses the reading order of the image information for each horizontal scanning line when the vertical scanning is reversed from the normal direction to the reverse direction. When reversing the reading order, when a frame memory is used as the image memory, a visually good image can be obtained by adopting thinning of a predetermined number of scanning lines.

Alternatively, the image information reading control circuit can read out the scanning line information in the vertical scanning in the reverse direction, in reverse to the time series in which the image information is stored in the image memory. In this case, it is preferable to use a RAM as the image memory.

In the driving apparatus for a display device according to the present invention, it is preferable that the image information read control circuit operates with a horizontal scanning clock having a frequency twice as high as that of the original image. In this case, the same resolution as the original image can be secured. Further, the driving method of the display device of the present invention,
A method of driving a display device that vertically scans a light beam including image information in a forward direction and a reverse direction by a resonance type optical scanner and outputs an image for each horizontal scanning line, wherein the method corresponds to the forward and reverse vertical scanning. Then, the image information is read from the image memory by designating the order of each horizontal scanning line of the image memory in a different order in the forward and reverse directions.

In the driving method of the present invention, the image information of the horizontal scanning lines having odd row numbers is sequentially read out in ascending order of the row numbers corresponding to the vertical scanning in the forward direction, and the vertical scanning in the reverse direction is performed. Correspondingly, it is preferable to sequentially read out horizontal scanning lines having even-numbered row numbers, starting from the one with the largest row number.

In a preferred embodiment of the driving apparatus and method of the display device according to the present invention, reading is performed at double speed or higher speed, and all the images to be displayed during the period when the horizontal scanning scanner is scanning in the forward direction. The data is displayed, and a different image is displayed during the forward scanning and the backward scanning of the vertical scanner by performing the thinning-out scanning.
Thus, an image having the original image resolution can be displayed.

For example, when the vertical scanner is moving in the forward direction, scanning lines having odd numbers among scanning lines constituting an accumulated image are displayed at double speed in numerical order. Then, when the scanner starts the reverse scanning, the scanning lines having the even-numbered scanning lines constituting the stored image are sequentially displayed at the double speed from the large number to the small number. By adjusting the display timing so that the positions displayed by going and returning are located in the middle of each other, an image having the same resolution as the original image is restored to human eyes.
Also, while the horizontal scanner is scanning in the reverse direction,
By providing a mechanism for stopping display of image information, the visibility is improved without overlapping images.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings based on embodiments of the present invention. First, a driving method of a display device according to a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1A shows scanning lines obtained by sequential scanning of an original image and their order. The scanning starts from the upper left end, scans from the left end to the right end along the first scanning line L1, and then goes down one step to the left end of the second scanning line L2. Hereinafter, scanning is similarly performed from the left end to the right end, and the last 10th scan is performed.
After reaching the scanning line L10, and reaching the right end of the scanning line L10, after a certain period, it returns to the initial position.

FIGS. 1B and 1C show a scanning method by a driving method of the display device in the embodiment. FIG. 1B shows scanning lines displayed during front scanning, that is, when the vertical scanning scanner is scanning in the forward direction. FIG. 1C shows scanning lines during back scanning. That is, it shows the scanning lines displayed when the vertical scanning scanner is scanning in the reverse direction. Scanning starts from the left end of the first scan line and proceeds toward the right end. Although not shown in the drawing, the horizontal scanning speed according to the driving method of the present invention is twice as fast as when the original image is scanned.

The display apparatus starts horizontal scanning of the first scanning line L1 from the left end and ends when reaching the right end.
The display is stopped and waits until the scanning time of the scanning line of the original original image comes. In the next display period for the second scanning line L2, the display is jumped to the third scanning line L2.
When the scanning time for No. 3 is reached, the scanning line L3 is displayed from the left end to the right end. Hereinafter, the fifth, seventh, ninth, and odd-numbered scanning lines are displayed in order from a small number to a large number.

Next, when a signal indicating that the vertical scanning scanner is performing reverse scanning is detected, as shown in FIG. 1C, the display is performed from the left end to the right end of the tenth scanning line L10. This display is also performed at twice the speed of scanning the original image as in the forward direction. When the scanning reaches the right end, the scanning is stopped until the scanning period of the even scanning line of the next original image is reached. When the display period of the eighth scan line L8 is reached, display is performed from the left end to the right end of the eighth scan line L8. Hereinafter, similarly, the scanning lines are sequentially displayed in the order of the sixth, fourth, and second, and from the larger number to the smaller number. Finally, when the vertical scanning scanner detects a signal scanning in the forward direction, it returns to the initial state and repeats the operation described above.

FIG. 2 shows a drive circuit of a display device according to a second embodiment of the present invention. The present driving circuit includes an RGB image signal source 2 obtained by scanning an original image.
1. An A / D converter 22 for converting a signal from the signal source 21 into a digital signal, a frame memory 23 for storing the digital signal, a D / A converter 24 for recovering the stored digital signal into an analog signal, 25, a light source 26 for generating light whose intensity is modulated by the amplified signal, a horizontal synchronous frequency oscillator 27 and a horizontal synchronous frequency oscillator 28 for driving a horizontal scanner 33 and a vertical scanner 34, respectively. , A PLL 29 for generating a read clock 38 necessary for reading an image signal stored in the frame memory in synchronization with the output of the oscillator, and a line control timing circuit 30.

The driving circuit of the embodiment operates as follows. An RGB image signal output from a television or a computer is converted into a digital signal by an A / D converter 22. The signal is obtained by synchronizing the horizontal scanning synchronization signal 31 of the RGB image signal source 21 with the PLL independently of the readout timing.
A signal generated by multiplying by 32 is used as a sampling clock, and is sequentially stored in a frame memory so that data of an input image is just stored.

In order to read out the image signal from the memory in synchronization with the horizontal scanner 33, the drive signal of the horizontal scanner is multiplied by the PLL 29 and the double-speed read clock 38
Generate For example, if the original signal is an NTSC television signal, a signal of 1820 times is generated and used as a read signal. Similarly, in order to generate an image signal synchronized with the vertical scanner 34, the horizontal and vertical synchronization frequency generators 27,
28, a reset pulse 35 for initializing the address of the frame memory via the line control timing circuit 30;
A row inversion pulse 36 for reversing the line to be scanned,
Then, a thinning-out designation pulse 37 for designating a line to be read is output.

The reset pulse 35 is a signal for transmitting the end of one field, and has a property similar to a vertical synchronizing signal in a general television signal. In general,
Since the frame memory can only be read in the forward direction, it is necessary to skip a large number of rows in order to read in the backward direction, and to return to the upper row apparently.
The row inversion pulse 36 generates a pulse obtained by subtracting 1 or 2 from the total number of vertical scanning lines, and applies the generated pulse to the frame memory 23 to determine the vertical scanning line number to be scanned. It controls the count number of the counter. For example, in the case of a normal television receiver,
Since there are 233 vertical scanning lines, 232 pulses may be input to the counter to display the immediately preceding row. When the above circuit is used, all the image information of one scanning line is displayed while the horizontal scanner 33 swings in the positive direction,
In addition, the image information of all the scanning lines is reproduced while the vertical scanner 34 reciprocates. For this reason, even if a normal image signal is applied to the optical scanning display device using the resonance scanner, it is possible to reproduce a screen having the same resolution as the original image.

FIG. 3 shows a drive circuit of a display device according to a third embodiment of the present invention. This drive circuit includes a random access memory (RAM) 3 instead of the frame memory 23 in the drive circuit of the second embodiment.
9 and address counters 41 and 42 independent of each other. The other configuration is the same as that of the second embodiment, and the same reference numerals are given and the description is omitted. In the frame memory, only sequential reading is possible, but in the present embodiment, the use of the RAM 39 enables the calling in any order. Therefore, the address counters 41 and 42 capable of controlling the direction of UP / DOWN are set to RA.
The circuit is simplified by using it for address designation of M39.

The acquisition and output of signals in this embodiment are almost the same as those in the second embodiment, but the method of specifying a scanning line is different. For example, image data on the same horizontal scanning line is specified using a memory address area of 9, 10, or 11 bits or less, and a row address uses the other area of 10, 11, or 12 bits or more. Do it. First, in order to accurately store the information of the original image, the horizontal scanning synchronization signal of the original image is multiplied by the PLL 32 to generate a sampling clock as in the previous embodiment. Using the sampling clock, A /
The D converter 22 is driven and written into the RAM 39.

The address to be written is an address counter 42 which advances the address in synchronization with the sampling clock.
Is determined by On the other hand, a read clock 38 generated by the horizontal synchronization frequency oscillator 27 that generates the resonance frequency of the horizontal scanner 33 and each control signal generated by the vertical synchronization frequency oscillator 28 that generates the resonance frequency of the vertical scanner 34 are sent to the address counter 41. By introducing,
The image data is read. In the present embodiment, the reading direction of the counter for determining the reading direction of the address counter is set to UP, which indicates the scanning direction of the vertical scanning scanner 34.
-Change according to the Down control signal 43. With this mechanism, as in the second embodiment, a scanning line to be read is determined, and thinning scanning is realized.

FIG. 4 shows the operation of the display device driving method according to the fourth embodiment of the present invention.
In the present embodiment, during a period in which the vertical scanner performs reverse scanning, horizontal scanning is performed from right to left, contrary to the usual left to right. This is realized using a RAM and a counter, as shown in the third embodiment. In other words, it can be realized by controlling the UP-Down control signal of the horizontal counter using a signal that detects that the vertical scanner is scanning in the reverse direction, and inverting the count direction in the reverse direction.

FIG. 5 shows a driving circuit of a display device according to a fifth embodiment of the present invention. This drive circuit displays an image by simply removing the overlap of the image. This drive circuit includes horizontal and vertical synchronous frequency oscillators 27 and 28, a PLL 29,
Instead of the line control timing circuit 30, a read clock generator 51 for generating a memory read clock obtained by multiplying a previously measured resonance frequency of the horizontal scanner 33 by an integral number of display pixels, and dividing the signal by a read clock generator 51 Divider 52 for obtaining various signals, and a horizontal sine wave oscillator 55 and a vertical sine wave oscillator 55 for generating a sine wave for driving the scanner in accordance with a horizontal synchronizing signal 53 and a vertical synchronizing signal 54 taken out from the frequency divider, respectively. A sine wave oscillator 56 and a switch 57 for cutting off a signal during a period of backward scanning in the scanners 33 and 34 are provided. With this configuration, an image reading signal synchronized with the operation of the horizontal scanner 33 and the vertical scanner 34 is obtained. Other configurations are the same as those of the second embodiment.

In the driving circuit of the present embodiment, the image signal D / A converted by the D / A converter 24 is supplied to the light source 26 through the amplifier 25, but the horizontal scanner 33 and the vertical scanner 34 operate in the opposite directions. A blanking signal is generated by a blanking signal generator 58 and a switch 57 is turned off so that no display is performed during the scanning period.
Images should not overlap on the screen. for that reason,
The number of displayable pixels in the horizontal and vertical directions is half of the original image, and a quarter of the image data is displayed as a whole.

In the first to fourth embodiments, a display device using a resonance type mirror scanner is used.
As with a conventional scanner using a sawtooth wave, an image having the same resolution at the same frame rate as the original image can be displayed. Further, since light is generated in the reciprocation of the vertical scanning of the scanner, twice the brightness can be obtained as compared with a conventional screen displaying only one direction. Since the image is displayed back and forth, the image can be changed at twice the speed of the conventional one. For example, when the frequency of the vertical scanner is 60 Hz, 120 Hz is used.
Thus, the image can be updated, and flicker causing flicker can be greatly reduced.

Also, since the horizontal reading signal is generated by multiplying the resonance frequency of the horizontal scanner using the PLL,
The display position of the image is automatically locked to the resonance frequency of the scanner, so that it is not necessary to perform the calculation and generate the original memory read clock as in the related art.

Further, if the resonance frequency of the scanner is automatically detected, an appropriate image can be displayed automatically without any adjustment. In the embodiment in which the RAM is used as the image memory, the address can be directly specified in the reverse direction, so that the scanning line can be accurately specified in the reverse direction even if the vertical scanning becomes faster. The double-speed reading performed during the horizontal scanning period can be easily performed by reading the lower bits with twice the normal clock, and does not require a special circuit for double-speed reading.

If the horizontal scanning direction is also reversed during the period when the vertical scanner is performing reverse scanning, all the scanning lines fall to the right, and the scanning lines are kept parallel to each other at the time of the vertical scanner. It is possible to obtain a uniform pixel density everywhere.

Although the present invention has been described based on the preferred embodiment, the drive circuit and method of the display device of the present invention are not limited to the configuration of the above-described embodiment. Various modifications and changes from the configuration of the embodiment are also included in the scope of the present invention.

[0036]

As described above, according to the display apparatus driving apparatus and method of the present invention, image data such as television signals can be visually displayed on a screen by a driving apparatus using a resonance type optical scanner. This has the effect of being able to display well.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating a driving method of a display device according to a first embodiment of the present invention, wherein FIG. 1A illustrates scanning of an original image, and FIGS. 1B and 1C illustrate forward and reverse directions, respectively. 3 shows a vertical scan.

FIG. 2 is a block diagram of a driving device of a display device according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a display device driving device according to a third embodiment of the present invention.

FIG. 4 is a view similar to FIG. 1 showing a method of driving a display device according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram of a driving device of a display device according to a fifth embodiment of the present invention.

6 (a) and 6 (b) are signal timing diagrams in a conventional display device driving method using a resonance type scanner.

[Explanation of symbols]

 L1 to L10 Scanning line 21 RGB image signal source 22 A / D converter 23 Frame memory 24 D / A converter 25 Amplifier (AMP) 26 Light source 31 Horizontal scanning synchronization signal 32 Phase synchronization circuit (PLL) 33 Horizontal scanner 34 Vertical scanner 35 reset pulse 36 row inversion pulse 37 thinning designation pulse 38 read clock 39 random access memory (RAM) 41 address counter 42 address counter 43 UP-Down control signal 51 read clock generator 52 frequency divider 53 horizontal synchronization signal 54 vertical synchronization signal 55 Horizontal sine wave oscillator 56 Vertical sine wave oscillator 57 Switch 58 Blanking signal generator

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G09G 5/36 530 G09G 5/36 530J H04N 3/30 H04N 3/30 5/66 5/66 B

Claims (8)

[Claims] An apparatus for driving a display apparatus of a type in which a light beam containing image information is vertically scanned in a forward direction and a reverse direction by a resonance type optical scanner and an image is output for each horizontal scanning line. An image memory for storing image information for each of the horizontal scanning lines according to the order of the row numbers of the horizontal scanning lines; and An image information readout control circuit for reading out image information from the image memory, respectively, as designated by the following. 2. The image information readout control circuit sequentially reads out image information of horizontal scanning lines having odd line numbers in ascending order of vertical line numbers corresponding to vertical scanning in a positive direction,
2. The display driving device according to claim 1, wherein horizontal scanning lines having an even row number are sequentially read in ascending order of the row number in correspondence with vertical scanning in the reverse direction. 3. The image information read control circuit includes: a clock generation circuit that generates a first clock based on a driving frequency of a horizontal scanner; and a counter that counts the first clock and sequentially addresses the image memory. And a line control timing circuit that generates a second clock based on the driving frequency of the vertical scanner and controls an address of the image memory based on the second clock. The control timing circuit
A reset signal for resetting the address of the image memory, an inversion signal for inverting the address of the image memory, and a thinning control signal for thinning out the address of the image memory corresponding to a horizontal scanning line are output. 2
A driving device for a display according to claim 1. 4. The driving device for a display device according to claim 2, wherein the image information read control circuit reverses the read order of image information for each horizontal scanning line when the vertical scanning is reversed from the normal direction to the reverse direction. . 5. The display device according to claim 2, wherein the image information readout control circuit reads out the scanning line information in the reverse vertical scanning in a manner opposite to the time series in which the image information is stored in the image memory. Drive. 6. The display device driving device according to claim 1, wherein said image information read control circuit operates with a horizontal scanning clock having a frequency twice as high as a horizontal scanning clock of an original image. 7. A method for driving a display device, wherein a light beam including image information is vertically scanned in a forward direction and a reverse direction by a resonance type optical scanner, and an image is output for each horizontal scanning line. A method for reading image information from the image memory by designating the order of each horizontal scanning line of the image memory in a different order in a normal or reverse direction corresponding to the vertical scanning. 8. In accordance with the vertical scanning in the forward direction, the image information of the horizontal scanning lines having odd row numbers is sequentially read out from the one having the smaller row number, and the image information of the even numbered rows is read in correspondence with the vertical scanning in the reverse direction. 8. The display driving method according to claim 7, wherein horizontal scanning lines having numbers are sequentially read out from a line having a large row number.