JP3362704B2 - Display device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image gradation display technique.

[0002]

2. Description of the Related Art Conventionally, as a technique for displaying an image with gradation by controlling the display time of a display element, for example, (1)
Kaji et al .: The Institute of Electronics and Communication Engineers Image Engineering Study Group Material, Material Number I
T72-45 (1973-03) (1973.3.1)
2) There is a technology for a memory-type plasma display described in "Display of halftone moving image by AC-type plasma display". This is because a constant light emission time (for example, one field of a television signal) is distributed as a display period width to a plurality of subfields weighted by binary codes, and the presence or absence of operation of each subfield is controlled. , To control the gradation of the image. Also, as a television-related technology that displays gradation by time division,
(2) Murakami et al .: Journal of the Television Society, vol. 38, N
o. 9 (1984) "Color television display by 8 type pulse memory type discharge panel" and (3) Kogami et al .: Technical Report of the Institute of Television Engineers, vol. 13, No. 58 (198
9) There is one described in "Reactive power recovery of Townsend light emitting type gas discharge television".

In the former case ((1)), as shown in FIG. 11, one field is divided into eight subfields b0 to b7, and each subfield is scanned and displayed within this subfield. .

In the latter ((2) and (3)), as shown in FIG. 12, one field has eight time regions (b0 to b7) (display period) having a length corresponding to each subfield of a binary code. ), The scanning is performed by shifting by 1H (horizontal scanning period) for each line, and the scanning pulse for the line address is slightly changed in each subfield so that the selection of the lines in each subfield does not become two lines at the same time. It is staggered.

[0005]

In the above-mentioned prior art, although the image quality deterioration of gradation display such as flicker may not be visually recognized depending on the device specifications, when the display screen becomes large or the brightness is When the height becomes high or a moving image has a moving image, gradation irregularities such as flicker can be recognized. In the display technique of FIG. 11, the display screen is dark because the light emission time for one field is short. For this reason, the gradation is not disturbed. Further, in the display technique of FIG. 12, since the number of scanning lines is small, the details of the image are not visible. Therefore, in this case as well, no disturbance in gradation is observed. However, for example, in a 40-inch class large gas discharge television whose brightness and screen size are larger than these cases, the maximum brightness of the image is 50 fL (≈171).
cd / m ² ) or more, and when an image is displayed by a method similar to the above-mentioned conventional technique, a remarkable gradation disorder occurs in a moving image. For example, in displaying a person's face, when a face moves, a phenomenon occurs in which white stripes run on the cheeks. That is, in the smooth gradation display, when the display image moves (so-called a moving image), streaks occur in the screen, and it seems as if the gradation subfield is missing. This is a phenomenon not seen in conventional cathode ray tubes.

The gradation irregularity in the moving image is caused by the instantaneous flicker of a specific pattern in the time division gradation display. This will be described below using the conventional gradation display technique of FIG.

FIG. 12 shows an example of gradation display of 256 gradations (8-bit gradation). For example, at the 127 gradation level, subfields b0 to b6 are activated, that is, the first half of one field emits light, and the gradation of the next field is increased by one level, 128 is the gradation level and b7 is activated, that is, the latter half of the field. Moreover, part of it emits light.
That is, the operating position of the operating subfield changes greatly from the first half to a part of the latter half of the field even if the gradation is increased by one level. The instantaneous light emission cycle at this time is from the light emission start time of the subfield b0 in the preceding field to the light emission start time of the subfield b7 in the subsequent field, and this time interval is 25 ms. This cycle 25m
s causes flicker, which causes disturbance of gradation. When the image is a moving image, this gradation disorder occurs in the cells of the screen one after another, and this appears as a visually clear line.

Next, the principle of the time-division gradation technique including the flicker will be described. As human visual characteristics, the brightness L
It is known that the brightness sensation L when 1 is displayed for t1 seconds and the luminance L2 is alternately displayed for t2 seconds is represented by L = (t1L1 + t2L2) / (t1 + t2) (Talbot- Plateau's Law (Television Handbook, Volume 1, Section 3.4, 55
page)). However, this law holds true when flicker is not felt (called fusion).

FIG. 13 shows a critical fusion period of visual characteristics when a white display light emission time width is changed and luminance is changed using a memory type gas discharge television, that is, a light emitting element is turned on or off at a constant luminance. The measurement results of a period in which flicker cannot be identified when lighting is repeated at a constant period are shown. In the figure, the upper broken line indicates the last subfield (b) of the next field from the start of the display period of the first subfield (b7) in the field according to the gradation display technique of FIG.
0) shows the time interval until the start of the display period (Fig. 11).
In the example, one field is equally divided into eight subfields). Further, the lower broken line in FIG. 13 indicates the display period of the last subfield (b7) in the next field from the start of the display period of the first subfield (b0) in the field by the gradation display technique shown in FIG. The time interval up to the start time is shown (in the example of FIG. 12, the display period of each 8-bit subfield in one field is 1: 2: 4).
...: weighted to 128 ratio). As can be seen from FIG. 13, in the conventional gray scale display technology of FIGS. 11 and 12, the luminance is several fL or more, and the last subfield of the next field from the start of the display period of the first subfield in a certain field. The interval until the start of the display period exceeds the critical fusion period. Therefore, when the light emission of each subfield changes as in a moving image, instantaneous flicker is felt especially on a bright screen, and gradation is disturbed. Normally, the average brightness required for a display device is 50f.
Since it is L or more, the critical fusion period of the above visual characteristics is 20.
It is desirable that the value be ms or less, but if the value is in the vicinity of this value, even if this value is exceeded, the gradation disorder is improved.

Further, in the above-mentioned prior art, the utilization factor of the time within one field as the light emission time is poor, that is, the light emission time is short, so that the brightness of the screen is lowered.

It is an object of the present invention to provide a technique for improving the drawbacks of the conventional technique, suppressing the disturbance of gradation even in a moving image or a high-luminance image, and increasing the light emission utilization rate within one field time. To do.

[0012]

In order to achieve the above object, according to the present invention, (1) in a display device for displaying an image with gradation using subfields, weighting by the number of display pulses is the highest. the sub-field level has a plurality in the field, during the display operation of the gradation level of the operative state a part of the sub-field of the plurality of top-level in at least two consecutive fields, the first field The highest level of
Subsequent based on the working state of the bell subfield
Creation of the highest level subfield in the second field
One of the plurality of choices of the operating states of the plurality of highest- level subfields is selected as the moving state, and the display operation is temporally dispersed to improve the image quality.

(2) In a display device for displaying an image with gradation using subfields, a plurality of subfields having the highest level weighted by the number of display pulses are provided in the field, and the plurality of subfields are provided. Two of the upper level subfields are placed before and after the period including all the subfields of other weight levels, and at least two field consecutive
Continue to the time display operation of the gradation level of the operative state a part of the sub-field of the plurality of top-level, first off
Based on the working state of the highest level subfield in the field , the highest level in the subsequent second field
Uppermost level the operating state of the sub-fields of the plurality
One of the plurality of operating state options in the subfield of the subfield is selected, and the display operation is temporally dispersed to improve the image quality.

[0014]

[0015]

[0016]

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a principle explanatory view for explaining the basics of the present invention. In this case, the number of scan electrodes is 240, and the signal to be displayed is 8 bits (8 subfields b0, b1,
b2, b3, b4, b5, b6, b7), each bit is encoded by a binary code so that 256 gradations can be displayed.

In the figure, the vertical axis indicates the horizontal scanning electrode 2.
40 lines (upper half of the display panel), the horizontal axis represents time for 2 fields (1/30 second (s)). In this explanatory view, the entire time range of one field is not allocated as a subfield, and the subfields are arranged in one direction. With such a configuration, the interval between the light emission start time of the first subfield b0 in the field (display time start time) and the light emission start time of the last subfield b7 in the next field (display time start time) (Tm) is set shorter than the critical fusion period (about 20 ms) of visual characteristics. The arrangement order of the sub-fields need not be limited to the illustrated order. The light emission time may be packed on the right side or the left side of the field. Further, in FIG. 1, when the order of subfields is reversed and the order is changed from b7 to b0 in the field, the emission of b6 of the next field is started from the emission start point of b7 (the display period start point). Start time (start of display period)
Is shorter than the critical fusion period (about 20 ms).

FIG. 2 is a diagram showing a circuit configuration example of a gas discharge television device as a display device according to the present invention.
The video signals G, B, and R separated into the green (G), blue (B), and red (R) color signals of the television signal are respectively A / D converters 1-1, 1-2, 1-3. 8 from the analog signal
Bit (8 subfields b0, b1, b2, b3, b
4, b5, b6, b7) digital signal (binary code)
And is stored in the frame memory (or field memory) 2. On the other hand, the reading of the frame memory 2 is performed by using the dedicated read ROM 5 so as to make the timing suitable for the gradation subfield. The read ROM 5 is operated by the counter 4 that counts the clock signal CLK. The counter 4 is reset by using a V (vertical synchronization) signal of the television signal or an H (horizontal synchronization) signal if necessary. Frame memory 2
Of the subfields (b0, b2 ...
It is performed by accessing the address in which the subfield signal of each scan electrode is stored at the timing of b7). Each subfield signal read from the frame memory 2 is applied to the shift registers 8 and 11 of the driver circuit for the auxiliary anode of the light emitting element, and further passes through the drivers 9 and 10 to generate the light emitting element of the gas discharge panel 3. The auxiliary anodes S1, S2, S3 ..., S1 ′, S2 ′, S3 ′ ...

On the other hand, ROM 6 for cathode and ROM 7 for anode
Uses the output of the counter 4 to shift the array signals of the subfields to shift registers 13, 14 and 17, 18, respectively.
Add to. Furthermore, the shift registers 13, 14 and 1
The respective signals from 7, 18 are applied to drivers 15, 16 and 19, 20 respectively, where they generate drive signals for the anode and cathode of the light emitting elements of the gas discharge panel 3. Anode lead wires A1, A2, A3 ... A240,
A241 ... A480 are provided, and cathode lead wires K1, K2, K3 ... K240, K241 ... K480 are provided on the cathode. These ROM, shift register and driver constitute a drive circuit for selecting a light emitting element to be displayed. In the case of this configuration example, since the gas discharge panel 3 is divided into the upper and lower parts, two scan electrodes can be driven simultaneously.

FIG. 3 is a partially enlarged view of the gas discharge panel 3 and shows the electrode wiring of the light emitting element. The gas discharge panel 3 is
A plurality of light emitting elements 30 are arranged in a matrix of rows and columns. The light emitting element 30 has three electrodes of a cathode, an anode, and an auxiliary anode, and has a memory function. Each light emitting element 3
0 cathode and anode are provided with a first electrode lead wire 32 (k1, k2, ... KL) and a third electrode lead wire 31 (A1, A2 ,. Is provided with auxiliary electrode lead wires 33 (S1, S2, ...) In the vertical direction. As described above, when the gas discharge panel 3 has the number of horizontal scanning electrodes l = 480 and the panel is vertically divided into two and simultaneously driven in two rows, the auxiliary electrode lead wire 33 is separated at the central portion of the panel. First electrode lead wire 32 (k
1, k2, ... kl), the third electrode lead wire 31 (A1, A2,
... Al) and the auxiliary electrode lead wires 33 (S1, S2, ...) are respectively connected to the cathode driver 19 (or 20) of FIG.
Drive signals from the anode driver 15 (or 16) and the auxiliary anode driver 9 (or 10) are added.

FIG. 4 is a view showing a cross section of the light emitting element 30. The first electrode (cathode) 22 is made of Ba, Ni,
It is formed of a material such as LaBa. On the other hand, a third electrode (display anode) 24 is formed on the face plate 28 by a printing technique. Further, the discharge space (display discharge space 25 and auxiliary discharge space 27) shown in the drawing is formed by stacking a number of spacers having holes, and the second electrode (auxiliary anode) shown in the drawing is formed.
23 are arranged. When discharge (display discharge) is generated between the first electrode 22 and the third electrode 24, ultraviolet rays are generated from the gas (Xe or a mixed gas of Ne-Xe, He-Xe, etc.) in the display discharge space 25, and The light body 26 emits light and a display is performed. What is called a pilot discharge (auxiliary discharge) occurs between the first electrode 22 and the second electrode 23, and whether this auxiliary discharge shifts to a display discharge between the first electrode 22 and the third electrode 24. Whether or not the pulse is applied to the second electrode 24 is controlled. Since this auxiliary discharge does not excite the phosphor 26, it does not affect the display light emission.

Next, the discharge state between the electrodes will be described with reference to FIG. In FIG. 5, Vk represents a voltage waveform applied to the first electrode lead wire, and 40 is a pulse for addressing one line of the gas discharge panel 3, which is called a first electrode scanning pulse. In the example of FIG. 5, the pulse width of the first electrode pulse is the same as the time width Δ assigned to address one line. For example, when the scanning time of each line is set to 1H and 240 lines are addressed in one field (the number of lines in the upper half of a panel in which two rows are simultaneously driven) and 8-bit gradation display is performed, Δ≈8 μs. Vs represents a pulse voltage waveform applied to the second electrode lead wire, and pulse 4
Reference numeral 1 denotes a second electrode pulse, which has a narrower pulse width than the first electrode scanning pulse 40 and is located behind the time width Δ. This second
The presence or absence of the electrode pulse 41 changes depending on the content of the television signal, that is, "1" or "0" of the subfield signal. VA represents the waveform of the pulse voltage applied to the third electrode lead wire. For the same line number of the first electrode lead wire and the third electrode lead wire, in the figure, the width of the width applied to the third electrode is shown. Immediately after the first electrode scanning pulse 40, the narrow pulse 41 is continuously applied by the number of pulses corresponding to the number of bits of gradation.

In the period III in the figure, the pulse 42 having a narrow pulse width is first applied to the third electrode. Since a large number of charged particles are present in the display discharge space 25 due to the switching in the period II, the pulse 42 causes the first electrode and the third electrode
A pulsed discharge occurs between the electrodes. Due to this pulsed discharge, further charged particles are generated in the display discharge space 25,
The next pulse 43 also discharges. Thus, in period III, the discharge continues while the pulse is continuously applied, or until a new voltage is applied to the first electrode to stop the discharge. This function is called a pulse memory function. This pulse discharge excites the fluorescent body 26 in FIG. 4 to emit display light.

When the display light is not emitted, the pulse 41 of the second electrode in FIG. 5 is removed. In that case, switching is not performed, and no discharge occurs between the first electrode and the third electrode, so that the number of charged particles in the display discharge space 25 of FIG. 4 is small. Therefore, no discharge is generated even when the pulses 42 and 43 are applied to the third electrode, and the fluorescent body 26 in FIG. 4 is not excited.

Therefore, the pulse 41 of the second electrode serves to control the discharge between the first electrode and the third electrode, and the display brightness is controlled by the presence or absence of this pulse.

FIG. 6 is an explanatory view for displaying an image on the gas discharge panel 3 in 256 gradations by an 8-bit binary code.
1 field of Fig. 1 (about 1 for NTSC TV signal)
/ 60 seconds (s) = 16.7 ms) in an enlarged scale. The figure shows a voltage waveform Vk applied to the first electrode and a voltage waveform VA applied to the third electrode. 1 for the first electrode
Eight scan pulses 40 corresponding to each subfield are applied between fields. Pulse 42 applied to the third electrode
Starts immediately after the application of the scanning pulse 40 and ends before the next scanning pulse 40 arrives, as shown in FIG. The number of each pulse 42 is equal to the number of subfields b0, b1, ...
It is proportional to the weight of the display period of b6 and b7, and the ratio is 1:
If 2: 4: 8 ...: 128, it is 2 depending on the combination.
56 gradations are realized. Control of whether or not to discharge the pulse train of each of the third electrodes is performed in the subfields b0 and b0.
It is determined whether or not there is a second electrode pulse (41 in FIG. 5) corresponding to the scanning pulses 1, ... b6, b7. In addition,
In FIG. 5, when the light emission in the period II cannot be ignored, the number of pulses of the third electrode is distributed in consideration of the resulting brightness. Here, the period from the start of the display period of subfield b0 in FIG. 6 to the end of the display period of b6 is 3.3 m.
When the absolute value of the number of pulses of the third electrode is determined so as to be about s, the above-mentioned critical fusion period is 20 (= 3.3 + 16.
7) ms, and the disturbance of gradation in the moving image is suppressed.

In the configurations shown in FIGS. 1 and 6, the display period start time of the first subfield of the subfield array in a certain field and the display period start time of the last subfield of the subfield array in the next field are started. In order to make the interval (Tm) from the time point shorter than the critical fusion period of the visual characteristics, the entire display period is set to be considerably short, but in order to extend the light emission time, at least the sub-field of the binary code configuration is used. Similar effects can be obtained by dividing one and operating the divided subfields in a time zone different from the subfield operation time zone in the case of FIGS. 1 and 6.

7 and 8 are explanatory views of an embodiment of the present invention.

In the embodiment shown in FIG. 7, the signal to be displayed is encoded by 8 bits (8 subfields b0, b1, ..., B7), and the highest subfield b7 is converted into subfield b71.
And b72 are equally divided, and the emission time region of b71 and b72 is 1
It is assigned to the first and last positions of the field, and the emission order (operation order) of each subfield is b71, b0, b1,
b2, ... b5, b6, b72 (b71, b
6, b5, ... B1, b0, b72 may be used). In this case, subfields b0, b excluding b71, b72
In terms of 1, b2, ... B5, b6, the first subfield of the field is b0 and the last subfield of the next field is b6. The interval between the light emission start points of the two subfields (display point start point) is 20.8 ms.
Therefore, it becomes almost the same as the critical fusion period, and the effect of improving the image quality of moving images can be obtained. In the case of the present embodiment, in the display device having the same structure as shown in FIG. 2, during one field (about 1/60 second (s) in the case of NTSC television signal), the first electrode is between one field. Scan pulses corresponding to the nine subfields b71, b0, b1, ... B6, b72 are applied. The pulse 42 applied to the third electrode is
It starts immediately after the scan pulse 40 is applied and ends before the next scan pulse 40 arrives. For example, if b7 is equally divided into b71 and b72, the number of each pulse corresponds to the subfields b71, b0, b1, ... b6, b72, and the ratio thereof is 64: 1: 2: 4: 8. ...: 64:64. In this case, b7 (pulse ratio 128, b7 = b71 + b72)
When turning on (operating state), two subfields b71 and b72 are turned on. Control of whether or not to discharge the pulse train of each of the third electrodes is performed by the pulse of the second electrode (40 in FIG. 5) corresponding to the scan pulse of the subfields b71, b0, b1, ... B6, b72 shown above. ). The scanning time of each line is set to 1H, and 240 lines are addressed in one field (the number of lines in the upper half of the panel which is driven simultaneously for two rows), and b71, b0, b1, ...
When 9 times of control are required, Δ = 1H / 9 = 7.05
μs. Also, using the vertical blanking period, Δ = 1
Field / 240 × 9 = 7.72 μs.

In the embodiment shown in FIG. 8, a signal to be displayed is coded with 8 bits (8 subfields b0, b1, ... b7), two subfields b6 and b7 are equally divided, and b6 B61 and b62, b7 b71 and b72. Place b61 and b71 at the beginning of the subfield array, and b62 and b72 at the end of the subfield array, and place the order in the field at b61, b71, b0, b.
1, b2, b3, b4, b5, b62, and b72. In this case, the first subfield in the field is b0, and the last subfield in the next field is b5. At this time, the interval between the light emission start times of the two subfields (display time start time) is 18.8 ms.
And the critical fusion period (20 ms) or less. In this example, the scanning pulse of the first electrode applied to one field is 10 per line, and the pulse width Δ is 1H / 10.
≈ 6.3 μs, but if the vertical blanking period is also used, Δ
≈6.9 μs.

FIG. 9 shows two of the field memories 91 and 92.
In the embodiment of FIG. 7, in order to further improve the image quality, the subfields b71, b72, b are calculated.
6 are controlled. Subfield b7
Is equally divided into b71 and b72, b6, b71,
All b7 2 have the same display period (the number of pulses of the third electrode). At that time, b6 = 1, b7 = 0 (1; operation (O
N), 0; b71, b72 when inactive (OFF),
It suffices to put one of the b6 into the operating state (ON), and b
When 6 = 0 and b7 = 1, any two of b71, b72, and b6 may be turned on. At this time, in the present example, which subfield is to be activated (ON) is determined from the state of b6, b71, b72 one field before. For example, in FIG. 9, when the second field is in the light emitting state, the previous field memory 91
Sub-field b according to the table of FIG.
6, b71, b72 ON (1; operation), OFF (0; non-operation) is determined.

In FIG. 10A, the first field is b6 =
When 1, b7 = 0, the second field is b6 = 0, b7
B6, b71, and b72 when changed to = 1 are shown. However, here, A indicates subfields b0 to b5, and a cross indicates that the value does not depend on the value of A, that is, A can be any value. On the contrary, FIG.
The case where the fields are b6 = 0 and b7 = 1 and the second field is changed to b6 = 1 and b7 = 0 is shown. Thus, for example, by controlling the subfields b6, b71, b72 of the subsequent field between the adjacent fields by the signal state of the previous field, the light emission time can be dispersed and the image quality for a moving image is improved. be able to. In addition, when changing from b6 = 0, b7 = 0 to b6 = 1, b7 = 0, or b6 = 0, b7 = 1, b6, b71,
The selection of the operation of b72 depends on the state of A. The above is the case where the subfield b7 is equally divided, but the same applies to the case where two or more subfields are divided. Although only the subfield b7 is divided in the embodiment of FIG. 7 and only b6 and b7 are divided in the embodiment shown in FIG. 8, other subfields may be divided. The selection of the fields to be divided and the arrangement of the display time areas are determined in consideration of the ease of the device configuration and the effect of improving the disorder of gradation display.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above embodiments. For example, the present invention also includes the case where the direction of the time axis in the subfield arrangements of FIGS. 7 and 8 is reversed. The display device according to the present invention is typically a gas discharge type television device using a gas discharge light emitting element, but the present invention is not limited to this.

[0036]

According to the present invention, it is possible to improve the disturbance of gradation without lowering the brightness of the image.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a circuit configuration example for an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration example of a gas discharge panel used in an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a light emitting device of a gas discharge panel used in an example of the present invention.

5 is a voltage waveform diagram for explaining the operation of the light emitting device shown in FIG.

FIG. 6 is a diagram illustrating the principle of the present invention.

FIG. 7 is a diagram showing an embodiment of the present invention.

FIG. 8 is a diagram showing an embodiment of the present invention.

FIG. 9 is a diagram showing an example of an arithmetic circuit used in the embodiment of the present invention.

FIG. 10 is a diagram showing an operation of the arithmetic circuit of FIG.

FIG. 11 is a diagram showing a conventional example of a gradation display technique.

FIG. 12 is a diagram showing another conventional example of the gradation display technique.

FIG. 13 is a diagram showing an example of measurement results of a critical fusion period.

[Explanation of symbols]

1 ... A / D converter, 2 ... Frame memory, 3 ... Gas discharge panel, 4 ... counter, 5, 6, 7 ... ROM, 8, 11, 13, 14, 17, 18, ... Shift register, 9, 10, 15, 16, 19, 20, ... Driver, 21 ... substrate, 22 ... Cathode, 23 ... auxiliary anode, 24 ... Display anode, 25 ... Display discharge space, 26 ... Fluorescent material, 27 ... Auxiliary discharge space, 28 ... face plate, 30 ... Discharge cell (light emitting element), 31 ... Third electrode lead wire, 32 ... First electrode lead wire, 33 ... second electrode lead wire, 91, 92 ... Field memory, 93 ... Arithmetic circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mutsumi Suzuki 1-280, Higashi Koigakubo, Kokubunji City, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (56) Reference JP-A-63-139485 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G09G 3/20 641 G09G 3/20 642 G09G 3/28

Claims (2)

(57) [Claims] 1. A display device for displaying an image with gradation using subfields, wherein a plurality of subfields having the highest level of weighting by the number of display pulses are provided in the field, and at least
During a display operation of a gradation level in which a part of the plurality of highest-level subfields are continuously operated in two fields , the subsequent operation is performed based on the operation state of the highest-level subfield in the first field. In the second field
The operating state of the highest- level subfield is selected from among the plurality of operating state options of the plurality of highest- level subfields described above , and the display operation is temporally dispersed to improve the image quality. A display device characterized by the above. 2. A display device for displaying an image having gradation using subfields, wherein a plurality of subfields having the highest level weighted by the number of display pulses are provided in the field, and the plurality of highest order subfields are provided. arranged two of the sub-field level before and after the period including all subfields other weight levels, low
Based on the operating state of the highest-level subfield in the first field during the display operation of the gradation level in which a part of the plurality of highest-level subfields are continuously operating in at least two fields. , The following second fee
The highest level subfield
Serial plurality of selecting one of the choices actuated state of the plurality of types of sub-fields of the top level, a display device which is characterized in that to improve the image quality temporally distributing the display operation.