JP2017129712A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device capable of suppressing distortion of an image without reducing a scan time.SOLUTION: An image display device 1 includes: a display unit 10 on which a plurality of display panels are arranged in a tile fashion; a video division unit 11 for generating a plurality of image data in which a video frame is divided according to a plurality of display panels 111; and a controller 16 that makes each display panel 111 emit light for a prescribed time after the image data is written in order into a plurality of scan lines in synchronization. The controller 16 performs control such that a delay time from writing of image data until start of light emission becomes shorter gradually in an order of writing into a plurality of scan lines.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display device that displays an image.

  Conventionally, large screen displays have been developed for the purpose of improving the sense of presence and immersion, but in order to realize a large screen display, the driving speed is increased by increasing costs and increasing wiring resistance and parasitic capacitance. There are various problems such as a decrease and an increase in power consumption. Therefore, as a means for easily increasing the screen, a large-screen image display device has been developed in which a plurality of display panels are arranged in a tile shape and one video is displayed on the entire plurality of display panels.

  Usually, in each single display panel, line-sequential driving is performed as shown in FIG. For this reason, the writing timing of each row (scanning line) of the display panel is different, and the writing timing of the last row is delayed by about one frame period from the first row. When such display panels are arranged in a tile shape, for example, when the vertical bar image 100 moves in the horizontal direction, as shown in the display example of FIG. 9B, the boundary 101 between the display panels A, B, and C is displayed. Lines are displayed discontinuously.

  Therefore, as shown in FIG. 10A, the distortion is eliminated as shown in the display example of FIG. 10B by performing simultaneous light emission driving on a plurality of display panels and matching the timing of light emission. There is also a method (see, for example, Patent Document 1).

International Publication No. 2013/105347

  However, in order to simultaneously emit light from a plurality of display panels, it is necessary to make the scanning time of one frame sufficiently shorter than one frame period and to ensure the light emission period. In order to increase the scanning speed, there are problems such as improvement in performance of transistors and drivers, reduction of wiring resistance and capacitance, and the like.

  An object of the present invention is to provide an image display device that can suppress image distortion without shortening the scanning time.

  An image display device according to the present invention includes a display unit in which a plurality of display panels are arranged in a tile shape, a video dividing unit that generates a plurality of image data obtained by dividing a video frame corresponding to the plurality of display panels, A control unit that sequentially writes the image data to a plurality of scanning lines in synchronization with each display panel and then emits light for a predetermined time, and the control unit starts light emission after writing the image data The delay time until this is controlled so as to gradually become shorter in the order of writing to the plurality of scanning lines.

  The control unit calculates the amount of movement of the subject recorded in the video frame based on the two pieces of image data that move forward and backward, and the greater the amount of movement, the smaller the delay in the light emission timing between the scan lines. You may control as follows.

  The control unit may perform control so that the light emission intensity increases as the light emission time for one frame period is shorter.

  The display panel may be an organic EL display module.

  According to the present invention, it is possible to suppress image distortion without shortening the scanning time.

It is a block diagram which shows the function structure of the image display apparatus which concerns on 1st Embodiment. It is a block diagram which shows the detailed structure of the display part and control part which concern on 1st Embodiment. It is a figure which illustrates the timing of writing of image data and light emission which concern on 1st Embodiment. It is a figure which shows an example of the circuit which comprises each pixel of the display panel which concerns on 1st Embodiment. It is a figure which illustrates the drive timing of the selection signal and light emission time control signal which concern on 1st Embodiment. It is a figure which shows the structure of the row drive driver part which concerns on 1st Embodiment. It is a figure which shows an example of operation | movement of the row drive driver part which concerns on 1st Embodiment. It is a figure which illustrates the timing of writing of image data and light emission which concern on 2nd Embodiment. It is a figure which illustrates the timing of writing and light emission of image data by line sequential drive. It is a figure which illustrates the timing of writing of the image data by simultaneous light emission drive, and light emission.

<First Embodiment>
The first embodiment of the present invention will be described below.
FIG. 1 is a block diagram illustrating a functional configuration of the image display apparatus 1 according to the present embodiment.

The image display device 1 includes a display unit 10, a video dividing unit 11, and a control unit 16.
The display unit 10 includes a plurality of display panels arranged in a tile shape. A part of the image data obtained by dividing the video frame is input to each of the plurality of display panels. As a result, one video frame is displayed as a whole of the display unit 10.

  The video dividing unit 11 generates a plurality of pieces of image data obtained by dividing a frame included in the input video signal corresponding to the plurality of display panels, and provides the generated image data to the control unit 16.

The control unit 16 performs aperture control for emitting light for a predetermined time after sequentially writing image data to a plurality of scanning lines in synchronization with each display panel.
At this time, the control unit 16 controls the delay time from the writing of the image data to the start of light emission to be gradually shortened in the order of writing to the plurality of scanning lines.

FIG. 2 is a block diagram illustrating detailed configurations of the display unit 10 and the control unit 16 according to the present embodiment.
The display unit 10 includes a plurality of display panels 111 that are hold-type image display modules. As a more specific example, the display panel 111 is an active matrix organic EL display module.

  The control unit 16 includes a signal processing unit 13, a row drive driver unit 14, and a column drive driver unit 15.

  The signal processing unit 13 receives image data for each display panel 111 divided by the video dividing unit 11, generates data for controlling data writing and light emission timing, and generates a row driving driver unit 14 and a column driving driver unit. 15 to send.

  A plurality of selection signal lines arranged in the horizontal direction are connected to the row drive driver unit 14. The row drive driver unit 14 supplies a selection signal to each of the plurality of selection signal lines. The row drive driver unit 14 is connected to a plurality of light emission time control signal lines along the horizontal direction. Each light emission time control signal line is connected with a plurality of light emission time control transistors existing in a region along the horizontal direction where the light emission time control signal line is arranged.

  A plurality of data signal lines arranged in the vertical direction are connected to the column drive driver unit 15. The column drive driver unit 15 supplies an image data signal of each pixel to each of the plurality of data signal lines.

FIG. 3 is a diagram illustrating image data writing and light emission timings according to the present embodiment.
In this example, the display unit 10 includes three display panels 111 (A, B, and C) arranged in the vertical direction as shown in FIG.

Each of the plurality of display panels 111 is sequentially scanned from the upper side of the drawing, and image data is written over approximately one frame period.
In addition, after the start of scanning, after a certain delay time, the light emission timing gradually approaches the writing time by sequentially emitting light at a speed higher than the scanning speed. Thereby, the deviation of the light emission period of each scanning line becomes smaller than the deviation of the scanning timing.

  As a result, for example, when the vertical bar image 100 moves in the horizontal direction, as shown in the display example of FIG. 3B, the distortion of the display image is reduced as compared with the conventional case (FIG. 9), and the display panel 111 (A , B, C), the degree of discontinuity at the boundary 101 decreases.

FIG. 4 is a diagram illustrating an example of a circuit constituting each pixel of the display panel 111 according to the present embodiment.
When a voltage corresponding to the image data level is applied to Vda at the same time as a voltage is applied to Vga according to the selection signal, a constant charge is accumulated in the capacitor C1 via the transistor Tr1.

  Further, when a drive voltage is applied to Vdd in accordance with the light emission time control signal, a current flows through the diode Del via the transistor Tr2, and the organic EL element emits light. The control unit 16 performs aperture control by controlling the timing at which the drive voltage is applied according to the light emission time control signal.

  Here, the capacitor C1 holds the charge corresponding to the image data for each pixel. However, since the delay time until the light emission is started is adjusted for each of the plurality of scanning lines by the control unit 16, the capacitor C1 is adjusted according to the delay time. The capacity of C1 decreases slightly. Therefore, the control unit 16 may adjust the drive voltage for the organic EL element based on the delay time. Specifically, the drive voltage is adjusted higher as the delay time becomes longer.

  FIG. 5 is a diagram illustrating the drive timing of the selection signal and the light emission time control signal output by the row drive driver unit 14 according to the present embodiment.

  When displayed at 60 Hz on an HD (High Definition) panel having 1080 horizontal lines, one frame is about 16.6 msec. If the scanning time per scanning line is 15 μsec, scanning of one frame is completed in a scanning time of 16.2 msec.

Assuming that the light emission time in one frame period is a time aperture of 5 msec, the signal processing unit 13 writes a data signal by the selection signal for the first line, delays by 10 msec, and then applies Vdd by the light emission time control signal. By doing so, the light emission timing is controlled. Subsequently, in the second line, the scanning timing is delayed by 15 μsec from the first line, but the light emission timing is delayed by only 6 μsec from the first line. The delay time of the nth line can be represented by a scanning timing of 0.015 × (N−1) msec and a light emission timing of 10 + 0.006 × (N−1) msec. In the final 1080th line, the scan timing is 16.185 msec after the first line scan, and the light emission timing is 16.474 msec after the first line scan.
Thus, by gradually shortening the delay time from scanning to the start of light emission, the light emission timing can be brought close to simultaneous light emission.

  Here, the scanning operation by the row driving driver unit 14 needs to hold the charge based on the data value of the pixel in the capacitor C1 and requires a certain writing time or more. Since this delay is performed by switching the power supply, this delay is very short compared to scanning, and thus such driving is possible.

In addition, since the light emission time becomes shorter as the display distortion is reduced by the aperture control of the present embodiment, it is necessary to increase the instantaneous luminance during the light emission period in order to keep the luminance integration at a constant level. Therefore, it is desirable to adjust the delay time with an appropriate balance that can reduce display distortion without excessively increasing the instantaneous luminance.
For this reason, in the case of an image of 60 fps, the light emission time is adjusted to be 50% or less of one frame period, for example, about 20 to 25%.

FIG. 6 is a diagram illustrating a configuration of the row drive driver unit 14 according to the present embodiment.
The row drive driver unit 14 includes a pixel selection shift register 141, an AND circuit 142, a pixel selection amplifier 143, a light emission time control shift register 144, and a light emission time control amplifier 146.

  The pixel selection shift register 141 sequentially outputs a selection signal for controlling whether or not to select an organic EL element to the display panel 111 for each of a plurality of scanning lines (selection signal lines) constituting the display panel 111. .

  The AND circuit 142 is arranged for each scanning line (selection signal line). The AND circuit 142 calculates the logical product of the selection signal output from the pixel selection shift register 141 and the gate pulse, and supplies the calculation result to the selection signal line via the pixel selection amplifier 143.

  The light emission time control shift register 144 controls the light emission time of the organic EL elements for all of a plurality of scan lines (1080 rows) for each period in which the pixel selection shift register 141 outputs a selection signal for one scan line. Are sequentially output and supplied to the light emission time control signal line via the light emission time control amplifier 146.

FIG. 7 is a diagram illustrating an example of the operation of the row drive driver unit 14 according to the present embodiment.
As shown in FIG. 7A, a clock pulse (CLK1) having a cycle of 15 μsec is input to the pixel selection shift register 141 to which a gate signal is input in order to sequentially scan the horizontal line at a cycle of 15 μsec.
On the other hand, as shown in FIG. 7B, the clock pulse (CLK2) having a period of 6 μsec is input to the light emission time control shift register 144 to which the aperture signal is input, so that the power supply voltage Vdd for controlling the light emission is controlled. The drive timing can be delayed by 6 μsec for each line.

  According to the present embodiment, the image display apparatus 1 controls the scanning timing and the light emission timing for each scanning line of the display panel 111 separately, so that the boundary of the display panel 111 is not increased without increasing the scanning processing speed. Suppresses distortion. Specifically, the image display device 1 sequentially performs scanning in one frame period as in the past, but regarding light emission, light is emitted sequentially at a higher speed than the scanning speed after a certain delay time after scanning. , Reducing the deviation of the light emission timing As a result, the image display device 1 can suppress image distortion without shortening the scanning time.

  In addition, the image display device 1 adjusts the driving voltage for causing the organic EL element to emit light according to the degree of reduction of the electric charge held in the capacitor C1 for each scanning line. Disturbances in the display image due to the delay time can be suppressed.

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described.
In the present embodiment, the control content by the control unit 16 is different from that in the first embodiment.

Specifically, the signal processing unit 13 calculates the amount of motion of the subject recorded in the video frame based on the input two pieces of image data that change in time, and the larger the amount of motion, the more the scanning line. Control is performed so that the delay of the light emission timing is reduced.
As the amount of motion increases, the distortion of the display image increases. In the display panel 111 corresponding to the region where the amount of motion is large in this way, the light emission period for each scanning line approaches due to simultaneous light emission, and thus distortion is suppressed. As a result, the image display apparatus 1 can improve the image quality by controlling the degree of distortion of the display image to be uniform throughout the display unit 10.

At this time, if the time aperture of light emission changes for each display panel 111, the apparent luminance also changes, so it is necessary to change the light emission intensity according to the time aperture.
Therefore, for example, the signal processing unit 13 converts the image data based on the following equation (1) so that the emission intensity increases as the emission time for one frame period is shorter.
Output data = input data × 100 / hour aperture [%] (1)
Here, the input data is a luminance value for each pixel recorded in the video signal.

FIG. 8 is a diagram illustrating image data writing and light emission timings according to the present embodiment.
In this example, the display unit 10 is configured by arranging three display panels 111 (A, B, C) in the vertical direction as in the example of the first embodiment (FIG. 3).

In the video frame, when it is determined that the amount of motion of the region B is larger than the regions A and C, the signal processing unit 13 sets the light emission time on the display panel 111 corresponding to the region B to the regions A and C. Compared to this, it is shortened, and the timing deviation for each scanning line is reduced.
Thereby, the distortion of the area | region B with a large motion amount is reduced more, and the equalization in the whole display part 10 is achieved.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. Further, the effects described in the present embodiment are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the present embodiment.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 10 Display part 11 Image | video division | segmentation part 13 Signal processing part 14 Row drive driver part 15 Column drive driver part 16 Control part 111 Display panel

Claims (4)

A display unit in which a plurality of display panels are arranged in a tile shape;
A video dividing unit for generating a plurality of image data obtained by dividing a video frame corresponding to the plurality of display panels;
A control unit that emits light for a predetermined time after sequentially writing the image data to a plurality of scanning lines in synchronization with each display panel;
The control unit controls the delay time from the writing of the image data to the start of light emission to be gradually shortened in the order of writing to the plurality of scanning lines.   The control unit calculates the amount of movement of the subject recorded in the video frame based on the two pieces of image data that move forward and backward, and the greater the amount of movement, the smaller the delay in the light emission timing between the scan lines. The image display device according to claim 1, which is controlled as described above.   The image display device according to claim 2, wherein the control unit performs control so that the light emission intensity increases as the light emission time for one frame period is shorter.   The image display device according to claim 1, wherein the display panel is an organic EL display module.

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