JPH04302289A - Display device - Google Patents

Abstract

PURPOSE:To smoothly eliminate the unnaturality of movement for a moving image by preparing an interpolating field and successively displaying it together with an input field or limiting a light emitting time rate to the range of 30-70% at the reception display device having the almost 100% light emitting time rate. CONSTITUTION:An intermediate field generator 1 outputs an output signal from an input video field signal while containing a field interpolating signal as well. For example, output side 2n-2, 2n-1...2n+2 fields are prepared from an input signal to the generator 1 and n-1, n, and n+1 fields and by successively displaying these fields, the movement is made smooth. As the other method, light emitting time is shortened and set to the range of 30-70%. By these methods, the unnaturality to the movement of the moving image is reduced, the image is made visually smooth and further, the illuminance of the image is not lowered.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device suitable for displaying moving images of image signals such as television signals, and having an analog memory in a display cell corresponding to each pixel.

0002

2. Description of the Related Art Conventionally, this type of display device has cells such as liquid crystal cells with a memory function, and each cell has a switch, and as shown in the schematic configuration diagram shown in FIG. The voltage was applied directly to the liquid crystal display device. In the configuration shown in FIG. 5, the input video signal is processed by the processor 11, and the pixel signals in the row direction are processed by the serial/parallel conversion column drive circuit 12.
The voltage is applied to a display device having memory-type liquid crystal cells 16 in a matrix, and row driving is performed through a row driving circuit 13. Each liquid crystal cell 16 has an analog memory function, and each cell continues to emit display light for approximately one field or one frame period depending on the amplitude of the input video signal at that time. Here, the term 1 field or 1 frame period means that in the case of interlaced scanning, 1 field period is used, and in the case of sequential scanning, 1 frame period is used.

0003

[Problems to be Solved by the Invention] In the liquid crystal display device using the conventional method as described above, even if the time response of the liquid crystal display cell itself becomes sufficiently fast, the light emission of any cell is determined by the interlaced scanning method. If one field time is TF, the result will be as shown in FIG. Typically, television signals are transmitted with 60 or 50 interlaced fields per second.
If the light is emitted as shown in FIG. 6, the movement of moving images will be unnatural and it will be difficult to obtain the visual sensation of smooth movement.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a display device which has a light emission time rate of approximately 100% and which reduces the unnaturalness of the movement of moving image display without reducing the total luminance. It is something to do. Here, the light emission time rate is the time ratio during which an arbitrary display cell continues to emit light for one field or one frame period.

[0005]

[Means for Solving the Problems] A display device according to a first invention for achieving the above-mentioned object is a display device having a large number of display cells each having an analog memory, each corresponding to a pixel of an image signal. and storing signals corresponding to pixels of the received input image signal in each corresponding memory for each field or frame, and causing the display cell corresponding to the memory to emit light at a voltage corresponding to the stored pixel signal. Control brightness, almost 1 field or 1
In a display device that causes its display cells to emit light continuously at the corresponding voltage during a frame period, the device interpolates at least one interpolated image signal to be interpolated between the fields or between the frames to the previous and subsequent fields or frame image signals. and means for displaying an image by sequentially using the formed interpolated image signal together with the field or frame image signal to reduce unnaturalness in image movement. It is characterized by the fact that it is made to do so.

[0006] A display device according to a second aspect of the invention is a display device having a large number of display cells each having an analog memory, each corresponding to a pixel of an image signal; The signals to be displayed are stored in the corresponding memories for each field or frame, and the light emission brightness of the display cell corresponding to the memory is controlled with a voltage corresponding to the stored pixel signal, and the display is performed with the corresponding voltage. A display device in which cells continuously emit light, the device comprising means for limiting the continuous light emitting period or effective light emitting period to a range of at least 30% to no more than 70% between each field or frame, It is characterized by reducing unnaturalness in image movement.

[0007]

[Operation] According to the display device of the present invention, when displaying a moving image in a display device having a light emission time rate of approximately 100%, interpolation is performed from an input field or frame signal to a receiving device, which is inserted between them. producing field or interpolated frame signals and displaying them sequentially with said input field or frame signals;
Since the nearly 100% light emission time rate is limited to a range of at least 30% to no more than 70%, the moving image becomes visually smoother, and the unnatural motion of the conventional example is eliminated. reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the accompanying drawings. In the following description, the relationships between field and frame signals and interpolation fields and interpolation frame signals are similar in the present invention, so only the relationships between fields will be dealt with. FIG. 1 shows a schematic configuration diagram of an embodiment of the display device of the present invention, which is not limited thereto. The intermediate field generator 1 shown in the figure has the function of outputting an output signal including a field interpolation signal as shown in FIG. 2 from an input video field signal.

In FIG. 2, the left column shows the input image signal (n-1) to the generator 1 with a field frequency of, for example, 60 Hz.
Field images of field, n field, and (n+1) field are schematically shown, and circles within each field of the image schematically show how the image moves from the left side to the right side of the figure for each field. The column on the right side of the figure shows the output image signal from the generator 1 of, for example, 120 Hz, whose field frequency is doubled according to the invention as the input image signal
2n-2), (2n-1), 2n, (2n+1), (
2n+2) field images are shown, and the circles within each field are model moving images thereof.

[0010] The solid arrow line from the left block to the right block in the diagram indicates which field's image information in the left block is used to create each field in the right block. For example, on the output side ( 2n-2), 2n
, (2n+2) field is input side (n-1), n, (
The (2n-1) and (2n+1) fields on the output side, that is, the interpolation field, are created from the image information of the (n-1) and n,(n+1) fields on the input side, respectively. Indicates that it is created from information. The interpolation field is not limited to this, for example, the (2n+1) field on the output side is the (2n+1) field on the input side.
4 of fields n-1), n, (n+1), (n+2)
Interpolation may be performed based on two field image information. Here, n is of course an integer of 1, 2, 3, . . . . Further, in this example, the ratio of the field frequency between the output and the input is 2, but it is obvious that the present invention is not limited to this.

The emission waveform of 120 fields generated by the intermediate field generator 1 is shown in FIG. Note that this is the period of the field.

The signals shown in FIGS. 2 and 3 can be obtained using a well-known method, for example, in the literature, Yutaka Tanaka et al.: Hi-Vision-PAL System Converter, NHK Technical Research, Vol. 39, No
．． 2, pp. 112-129, 1987. That is, this method divides the entire screen into several zones, detects the movement of the image, estimates where the image is at a certain time, and interpolates it. In the case of uniform motion, an interpolation field can be created from two adjacent fields and inserted between them. Furthermore, if there is first-order acceleration, it is possible to create an interpolation field by predicting from a total of four fields, two before and after. By displaying the fields thus created (output field in FIG. 2) in a row, it is possible to display sufficiently smooth movement even if the light emission time rate of the display device is approximately 100%. However, it is said that the lower limit of this field frequency is about 40 Hz. Interlaced scanning signals and progressive scanning signals are handled somewhat differently, but they can be handled using well-known methods.

Another method for smoothing the movement is to shorten the light emission time, but if this is carried out, the light emission brightness of the display device decreases. Therefore, as shown in FIG. 4(a), if the light emission time is set within a range of at least 30% to no more than 70%, the movement will be smooth. This is the second invention described herein. The above-mentioned range has been experimentally confirmed by the inventors of the present application, and is also known from the above-mentioned literature. Furthermore, in this second invention, the light emission waveform does not need to be completely rectangular, and even if the integral value of the light emission is made to be effectively equal to the time width of the above-mentioned %, as shown in FIG. 4(b). good.

Finally, devices to which the display method according to the present invention can be applied are listed below. Examples of the light amount control type include liquid crystals, devices using the Kerr effect, Franz-Keldish effect, Faraday effect, and other electrical and magneto-optical effects; There is an element that uses ultrasonic waves etc. in the middle, and as a light emitting type, E
L (electroluminescence), LED (light)
emitted devices), PDPs (plasma display panels), matrix-type CRTs (cathode ray tubes), and large displays with arrays of light emitting elements.

[0015]

Effects of the Invention As described above in detail, according to the display device of the present invention, in a display device having a light emission time rate of almost 100%, the receiving display side performs signal processing different from the conventional one to display an image. Therefore, when displaying a moving image, the unnaturalness of the movement of the moving image is reduced, the moving image becomes visually smooth, and the brightness of the image does not have to be lowered.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of an intermediate field generator.

FIG. 3 shows a light emission waveform of an arbitrary cell when the display device of the present invention is used.

FIG. 4(a) shows a light emission waveform in an example in which the light emission time is shortened according to the present invention, and FIG. 4(b) shows a light emission waveform in an example in which the same light emission time is substantially shortened.

FIG. 5 is a schematic configuration diagram of a conventional image display.

FIG. 6 shows a light emission waveform of an arbitrary cell according to a conventional image display.

[Explanation of symbols]

1 Intermediate field generator 2 Processor 3 1-field storage type display device 11 Processor 12 Serial-para conversion column drive circuit 13 Row drive circuit 14 1-field storage type display device 15 Switch 16 Memory type liquid crystal cell

Claims (2)

[Claims] 1. A display device having a plurality of display cells each having an analog memory corresponding to a pixel of an image signal, the display device comprising a plurality of display cells each having an analog memory corresponding to a pixel of an image signal, the field of which is a signal corresponding to a pixel of a received input image signal to each corresponding memory. Alternatively, the luminance of the display cell corresponding to the memory is controlled by a voltage corresponding to the stored pixel signal for each frame, and the display cell is continued at the corresponding voltage for approximately one field or one frame period. In a display device that emits light, the device motion-adaptively forms at least one interpolation image signal to be interpolated between the fields or between the frames from the previous and subsequent fields or frame image signals, and the formation thereof. and means for displaying an image by sequentially using the interpolated image signal together with the field or frame image signal to reduce unnaturalness in the movement of the image. 2. A display device having a plurality of display cells each having an analog memory corresponding to a pixel of an image signal, wherein a signal corresponding to a pixel of a received input image signal is fielded into each corresponding memory. Alternatively, in a display device that stores pixel signals for each frame, controls the light emission brightness of the display cell corresponding to the memory with a voltage corresponding to the stored pixel signal, and causes the display cell to continuously emit light with the corresponding voltage. The apparatus includes means for limiting the continuous light emission period or effective light emission period to a range of at least 30% to no more than 70% between each field or frame to reduce unnaturalness of image movement. A display device characterized by: