JPH0886999A - Display device - Google Patents

Abstract

PURPOSE: To attain a display without a flicker and with high definition. CONSTITUTION: In a display device writing a display image on a display panel constituting pixels in matrix by scan electrode groups S1-S1024 and information electrode groups by impressing selection signals MA-MC, MD-MF of which polarity of voltage for common potential is inverted to the scan electrodes at every one field or one frame of the display on the display panel and information signals generating prescribed display conditions to the information electrodes, dummy signals Ha-Mf temporarily fluctuating the transmission light quantity of the pixel corresponding to the scan electrode are impressed to at least one piece of the scan electrodes existing in a non-selection state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to arranging scan electrodes (scanning signal lines) and information electrodes (information signal lines) in a matrix, and applying and driving scan signals and information signals respectively. The present invention relates to a display device that displays an image or video.

[0002]

2. Description of the Related Art Conventionally, as a display device of a television receiver, a personal computer (hereinafter abbreviated as PC) or a work station (hereinafter abbreviated as WS), a CRT (Ca
the Thode Ray Tube) has been used. In recent years, TN (Twisted Nemati)
c) and STN (Super Twisted Nema)
The liquid crystal display device having a structure such as a tic) structure is used for an in-vehicle television receiver, a navigation display device, a video camera playback display device, a laptop PC, etc. because of its advantages of light weight, thin shape, and power saving. It has become to. Since these display devices including plasma display devices other than the above do not have a memory property, they are sequentially scanned at a frame frequency of 60 Hz or higher.

On the other hand, under these circumstances, both Clarc and Lagerwall have been published by JP-A-56-107.
The display device having ferroelectricity proposed in Japanese Patent No. 216, U.S. Pat. No. 4,367,924 and the like has a memory property of image information, and therefore, compared with the above display device.
The number of scanning lines can be increased and high-definition display is possible. But,
One of the factors is that the scanning time increases in proportion to the high-definition display, and when used as a display device of a man-machine interface, a decrease in the frame frequency causes a flicker phenomenon and becomes a problem.

As a proposal for this problem, there is a partial rewriting scan (Kanbe et al., US Pat. No. 4,655,561) which preferentially drives a scanning line with changed image information. A frame rate improving method called "multi-interlaced scanning + partial rewriting scanning" is proposed in Japanese Patent Laid-Open No. 63-65494 of Katakura et al.

Further, by applying a dummy signal to at least one of the scanning lines in the non-selected state to temporarily change the display state of the pixel corresponding to the scanning line, the flicker phenomenon due to the decrease of the frame frequency is prevented. Prevention is proposed in Japanese Patent Application Laid-Open No. 6-18853 by Okada et al.

Among these display devices, there is a liquid crystal display device in which a so-called AC drive is required to be switched between positive and negative voltages with respect to a common potential of a drive waveform in a constant cycle when driving. This AC drive method is 1
A method of switching the positive and negative of the drive waveform voltage in the horizontal scanning period,
A method of switching the positive / negative of the drive waveform in one field or one frame, a method of switching the positive / negative of the drive waveform in both one horizontal scanning and one field or one frame are known.

[0007]

When the above-mentioned matter is considered from the viewpoint of flicker, the recognition state varies depending on whether or not the display device has a memory property and the scanning method of the display device.

Specifically, the frame frequency at which flicker is not recognized in the ferroelectric liquid crystal display device having a memory property needs to be 40 Hz or higher when performing sequential scanning.

Furthermore, the flicker phenomenon is what the human visual sense recognizes the change in the light quantity of the information writing portion in the screen, and the degree of recognition changes depending on the relationship between the lightness and darkness of the entire screen and the lightness and darkness of the written information. . For example, in the case of ferroelectric liquid crystal, a scanning method is known in which writing is performed after erasing in order to effectively use the memory property. In this case, the flicker recognition method differs depending on whether writing is performed after dark erasing or writing is performed after bright erasing. In fact, the latter, in which the screen is dark and the image is erased, gives more flicker.

In such a situation, some of the display devices are driven by performing the voltage inversion of the drive waveform in the above-mentioned one field or one frame in order to perform the AC drive. Considering this case, the dark erasing and the bright erasing of the selective scanning are switched at a speed of “1 ÷ (number of scanning lines ÷ 2)” as compared with the case of reversing by one horizontal scanning. The recognition of is made explicit.

In the actual driving of the ferroelectric liquid crystal, there is an example in which the selection time of one scanning line is about 100 μs, and when writing information in a sequential scan on a panel having 1024 scanning lines, the frame frequency is 9. It is 6 Hz. At this time, when the driving waveform is used in the one-field or one-frame inversion method, the panel clearly recognizes flicker.

The present invention has been made in view of the above problems in the prior art, and an object of the present invention is to provide a marking device capable of high-definition display without flicker.

[0013]

In order to achieve the above-mentioned object, in the present invention, in consideration of the above-mentioned flicker generation condition, the amount of light transmitted through a pixel is temporarily set to at least one of the scanning lines in the non-selected state. By using the dummy scanning for changing to 1 and the writing scanning for inverting the driving waveform in one frame or one field, the occurrence of flicker is suppressed.

In this new combination, the driving method in which the driving waveform is inverted in one field or one frame switches the dark erase and the bright erase of the selective scan at a low speed.
The flicker cannot be reduced unless the waveform of the dummy scan inserted at the time of non-selection is appropriate.

First of all, the change in luminance change is 1
Due to the slowness of each frame or field, it is necessary for human vision to insert an interpolating dummy scan at a distance where averaging can be performed.

The second is a dummy signal for temporarily changing the amount of transmitted light of the pixel corresponding to the non-selected scanning line, but in reality, it is different from the information signal having the same dark information depending on the polarity of the dummy waveform. Even in the combined signal, a difference may occur in the pulse width of the waveform as in the O waveform of FIG. 15 or the S waveform of FIG. In such a case, the amounts of transmitted light due to fluctuations of liquid crystal molecules that are visually averaged differ between the two.
In addition, the selective scan is inverted every frame or field for AC driving, but the dummy signal has a waveform that is completely symmetrical with respect to the common potential, so that the dummy signal does not appear every frame or field. No need to flip. Due to the above two points, in order to suppress flicker, the voltage of the dummy scanning waveform should not be inverted in units of low frequency one frame or one field that hinders visual averaging.

Thirdly, since the cause of flicker is a change in brightness at a low speed, the change in brightness within one frame or one field as well as the change in brightness within one frame or one field occurs. , It is even slower and it is better to make them equal enough. To this end, it has been found that the optimum condition exists by increasing the absolute value of the voltage of the dummy scanning waveform as shown in FIG. 8 or by increasing the number of dummy scanning lines and increasing the amount of transmitted light as shown in FIG. .

[0018]

In general, the scanning of the display device has been aimed at writing and holding the image information for a sufficient time for visually recognizing the transmitted light amount of the target pixel such as writing or erasing (belonging to writing) image information. Therefore, the number of scanning lines that are simultaneously scanned in one frame is one (excluding screen split driving, simultaneous writing of a plurality of lines, etc.). Therefore, conventionally, when one luminance change is visually averaged over the area of the display screen, the luminance change is displayed at a high speed that cannot be recognized.

However, according to the present invention, when the frame frequency cannot be increased sufficiently to suppress the flicker due to the increase in the number of scanning lines of the display device or the characteristics of the liquid crystal material, Is displayed by using a dummy scan that causes the display element to temporarily fluctuate the amount of transmitted light in the display screen when an inversion drive waveform that causes a change in luminance at a low speed of one frame or one field is used. It is possible to suppress flicker recognition by visually averaging the changes in brightness of the in-plane scanning.

[0020]

According to the present invention, it is possible to gradually reduce the flicker to the extent that display failure occurs only by selective scanning, and it is possible to improve the display quality of the display device.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows a sectional structure of a cell of a display panel manufactured and used as an example of an object to which the present invention is applied. The cell shown in FIG. 4 is composed of glass substrates 11a and 11b on which transparent electrodes 12a and 12b forming matrix electrodes are arranged so as to face each other, and an electric field sandwiched between these substrates and applied via the matrix electrodes. The ferroelectric liquid crystal 15 that can take the first stable state and the second stable state is provided. As the liquid crystal material, chiral smectic liquid crystals (SmC *, SmH *) were used. When the layer thickness of the liquid crystal material is large, the long axes of the liquid crystal molecules exhibit twisted alignment, and therefore the liquid crystal is arranged between layers that are sufficiently thin (for example, 1 to 3 μm) so that twisting of the molecules does not occur. Alignment films 14a and 14b are provided in contact with the liquid crystal 15, and these alignment films are rubbed with a cloth to align the molecules of the liquid crystal 15. This rubbing is performed by shifting the rubbing direction of the lower substrate by 190 degrees with respect to the rubbing direction of the upper substrate. Glass substrates 11a and 11b
Polarizing plates 10a and 10b are arranged in crossed Nicols outside each of them, and control the light transmitted through the liquid crystal 15 layer. In order to control the thickness of the liquid crystal layer 15 and keep it uniform, the alignment film 1
A bead spacer 16 is arranged between 4a and 14b. In addition, the alignment films 14a and 14b and the transparent electrodes 12a and 1
Insulating films 13a and 13b are provided between the transparent electrodes 12a and 2b for the purpose of preventing the transparent electrodes 12a and 12b from being short-circuited with the liquid crystal 15 layer interposed therebetween. As shown in FIG. 5, the panel electrodes are composed of 1024 scanning-side electrodes S1 to S1024 and 960 information electrodes I1 to I960.

In the liquid crystal panel, a liquid crystal material 15 containing a pyrimidine component and having the characteristics shown in Table 1 was used as the ferroelectric liquid crystal material.

[0024]

[Table 1] Next, driving of the liquid crystal panel will be described. The liquid crystal panel is driven by using the selection signal, the information signal and the dummy signal. The selection signal is a signal for writing image information for displaying an image on a display screen for each scanning line. The signal causes a potential difference with the information signal applied to the information line. As a result, the spontaneous polarization of the liquid crystal 15 in FIG. 4 acts on the electric field, the orientation of the liquid crystal molecules is determined, and the birefringence of light caused thereby is determined by the polarizer 1.
The combination of 0b and the analyzer 10a is displayed as light and dark. As the selection signal, a method is known in which a reset signal for temporarily dark erasing or bright erasing a pixel is used in combination. Further, the information signal is a signal that determines the display state by causing a potential difference from the selection signal and changing the orientation of the liquid crystal molecules as described above. Then, for the non-selected scanning lines, a voltage is selected so that the information signal does not change the state of the pixel. Further, the dummy signal causes fluctuation of liquid crystal molecules due to the potential difference from the information signal, and temporarily changes the light transmittance. However, when the signal is removed, the liquid crystal molecules revert to their previous state. Of these signals, the voltage and waveform of the dummy signal are preferably selected as appropriate according to the voltage of the selection signal and the information signal and the characteristics of the liquid crystal material. More specifically, the waveform of the dummy signal is set so that the potential difference between the dummy signal and the information signal and the energy due to the time do not exceed the energy of the molecular inversion of the liquid crystal. The luminance change on the screen due to this scanning is visually averaged together with the luminance change of the selection signal. Therefore, the flicker can be gradually reduced at a low frame frequency by adjusting the number of simultaneous scanning lines of the dummy signal, the scanning positional relationship with the selection signal, and the mutual transmitted light amount.

Here, in the drive waveform of the AC drive in this embodiment, the polarity is inverted every one frame or one field after scanning the entire surface with the same polarity waveform for one frame or one field (hereinafter referred to as 1F). Inverted and abbreviated) used. In this embodiment, 1F inversion scanning shown in FIG. 6 was performed. FIG. 7 shows the waveform used in the main scan. In FIG. 7, SEL represents a selection signal waveform, SEG represents an information signal waveform, and DM described below represents a dummy signal waveform. The selection signal waveform SEL includes a reset pulse P1 and a selection pulse P2. Further, the information signal waveform SEG has the selection periods Q1 and Q having image information.
The auxiliary period Q2 cancels the DC component of 1. Further, the dummy signal waveform DM is composed of an AC waveform such that no DC component remains, and is provided with a voltage and time at which the pixel information does not change due to the difference from the information signal SEG. Here, 1 Ha indicates an image information erasing period of the scanning line, and 1 Hb indicates a writing period of image information of the scanning line. Further, Δt is each selection pulse P2
And Q1 and P1 and Q2 are synchronized.

First, a case where dummy scanning is simply applied to 1F inversion sequential scanning will be described as a comparative example with reference to FIGS. FIG. 10 shows a sequential scan in which the MA waveform, the MB waveform, the MC waveform, ... And the selection waveform are sequentially applied from the scan line S1 every horizontal scanning period (T ₁ , T ₂ , ...). Showing up. Then, after scanning the scan line S1024, the second frame starts from S1 and is sequentially applied.
The waveform, the ME waveform, and the MF waveform are waveforms in which the voltage is inverted with respect to the common voltage, and the polarity of the voltage is switched for each frame. In the MA waveform, dark erase is performed by the reset pulse, and in the MD waveform, bright erase is performed. The frame frequency of this display device is 9.6 Hz, and flicker due to selective scanning is recognized. Furthermore, as described above, the MA waveform and M
In the D waveform, there is a difference between dark erasing and bright erasing, and the switching frequency thereof is as slow as one frame unit, so the luminance difference is clearly recognized as a flicker on the screen. Regarding these erase waveforms, first, the case of the MA waveform and the dark information signal K is shown in FIG. The selective waveforms are the MA waveform, the dark information signal K waveform, and the composite waveform thereof is the L waveform. L
The waveform is dark erased by the pulse L1 and is not written thereafter. Then, the MA waveform and the bright information signal M
The case is shown in FIG. The selected waveform is the MA waveform,
The bright information signal has an M waveform, and its composite waveform has an N waveform. With respect to the N waveform, dark erasing is performed by the pulse N1, and then bright writing is performed by the pulse N2. FIG. 13 shows the case of the MD waveform and the dark information signal K. The selected waveform is the MD waveform, the dark information signal is the K waveform, and the composite waveform thereof is the Q waveform. With respect to the Q waveform, bright erasing is performed by the pulse Q1 and then dark writing is performed by the pulse Q2. FIG. 14 shows the case of the MD waveform and the bright information signal M. The selection signal is the MD waveform, the bright information signal is the M waveform, and the composite waveform thereof is the R waveform. With respect to the R waveform, bright erase (R1) is performed by the pulse R1 and writing is not performed thereafter.

Here, it is known to use both selective scanning and dummy scanning as a method for solving flicker due to a low frame frequency. In this dummy scanning, as shown in FIG. 15, the combined waveform O of the dummy signal Ma and the dark information signal K does not change the pixel to the dark state or the bright state. Also, FIG.
As shown in FIG. 6, neither the composite waveform P of the dummy signal Ma and the bright information signal M changes the pixel to the dark state or the bright state. 17 and 18 show the case of scanning with the inverted waveform md of the dummy signal Ma. Also in this case, the composite signal S and the composite signal T do not change the pixel to the dark state or the bright state. However, it can be seen that, with respect to the same dark information signal K, there is a difference in the positive or negative pulse area of the waveform between the combined signals O and S with the dummy signal, and there is a difference in the liquid crystal molecule oscillation energy. Therefore, a difference in the amount of transmitted light appears in these dummy scans. For example, as shown in FIG. 10, if dummy scanning is started every 256 horizontal scanning periods after the selective scanning is started, T ₁ (selective scanning), T ₂₅₆ (dummy scanning), T ₅₁₂ (dummy scanning) and Four scans of T ₇₆₈ (dummy scan) are simultaneously performed, and the frame frequency is apparently 38.4 Hz. At this frame frequency,
Flicker was almost unrecognizable. However, in the case of 1F inversion scanning, the selection scanning signal waveform MA,
Since MB and MC and MD, ME and MF are voltage-reversed around the common potential, the change in luminance for each frame is recognized as flicker. Also, the dummy scanning waveform M
Since a, Mb and Mc and md, me and mf are also voltage-reversed around the common potential, the change in luminance due to the difference in fluctuation of the liquid crystal molecules in each frame is recognized as a further flicker. FIG. 19 shows the subjective evaluation value of flicker with respect to the frame frequency when the liquid crystal display device is driven by these drive waveforms. It should be noted that the evaluation represents a display state in which flicker is less noticeable as the value approaches 5 in the 0-5 value evaluation. In this evaluation, the evaluation is performed by scanning the dark screen where flicker is easily recognized. In this graph, the flicker is improved together with the frame frequency, but the visual sense becomes more sensitive when the light is erased on a dark screen.
Flicker for each frame is recognized. Therefore, the final improvement of flicker due to this scanning does not provide sufficient image quality. In this graph, the black 0 flicker is
For the selective scan only, the black 3 × 3 flicker is such that dummy scans that are continuous for three horizontal scan periods are inserted every 256 horizontal scan periods, and one selective scan and three dummy scans are performed in one frame. The × 3 flicker indicates that dummy scanning that is continuous for three horizontal scanning periods is inserted every 128 horizontal scanning periods to perform one selection scanning and seven dummy scanning in one frame. FIG. 20 shows the results of subjective evaluation of flicker by changing the dummy waveform voltage. This shows that it is possible, but not sufficient, to raise the voltage and improve the flicker a little.

Next, an embodiment of the present invention will be described with reference to FIGS.

The present inventor has confirmed that even in the case of 1F inversion scanning, it is effective to reduce flicker by selecting the dummy waveform and the method of dummy scanning. Figure 1 shows the scanning method.
Shown in In FIG. 1, the selective scan in the first frame is performed by the dark erase waveforms of the MA waveform, the MB waveform and the MC waveform, and the second scan
The selective scanning of the frame is performed to clear the MD waveform, the ME waveform, and the MF waveform. However, in the case of the present embodiment, the dummy scan does not invert the waveform voltage in the first frame and the second frame. As a result, the selection signal repeats dark erasing or bright erasing for each frame, but since the dummy scanning is not reversed, fluctuations of liquid crystal molecules do not change and flicker is expected to be improved. The result is shown in FIG. 2 as a frame frequency versus flicker subjective evaluation value. Here, the reason why the number of dummy scans in one frame is set to 23 is that it is better to insert seven dummy scans in one frame as shown in FIG. 19 in consideration of visual averaging.
This was because the flicker was improved in the case of three lines and in the case of three lines as compared with the case of only selective scanning. The reason for this phenomenon is that in the case of 1F inversion driving, a bright change in brightness due to selective bright erase scanning in a dark screen where flicker is noticeable is 1.
Since it is slower than the H inversion drive, the dummy scan inserted at this time has a sufficiently larger average transmitted light amount than the brightness change due to this selective scan, and it is possible to suppress the total brightness change when both scans cooperate. This is because it is necessary to reduce flicker. Therefore, the dummy scan used here differs from the conventional usage of merely increasing the apparent frame frequency. In the case of 1F inversion drive, 1
It is also necessary to minimize the difference in brightness due to dummy scanning and information signals between frames. What should be noted here is that even if 23 dummy scans are performed in the same frame in FIG. 2, “dummy voltage (voltage polarity of dummy waveform)” shown in parentheses.
That is, "1F inversion not performed" is more effective in reducing flicker than "dummy voltage (voltage polarity of dummy waveform) 1F inversion (present)". This is based on FIG. 10 and FIG.
This is due to the difference in whether or not there is the waveform voltage inversion in the dummy scan in the unit of one frame described in 1. Not inverting the dummy scanning waveform voltage has the effect of avoiding nonuniformity of the composite waveform of the dummy waveform and the information signal in units of one frame, and making the amount of transmitted light due to dummy scanning closer to uniform. Similarly, using the dummy scans in a bundle for the even scan period is also useful for making the amount of transmitted light in each frame uniform. FIG. 3 is a graph showing the voltage of the dummy scanning waveform and the subjective evaluation value of flicker, and the flicker becomes inconspicuous as the voltage is increased and the amount of transmitted light is increased. From these results, if the frame frequency and the voltage of the dummy waveform are appropriately selected by using the dummy scanning as described above, the flicker can be reduced even in the 1F inversion drive in which the flicker is very easily recognized. It was According to the present embodiment, an appropriate amount of transmitted light is applied to a display device using an AC drive that inverts the waveform voltage polarity of selective scanning for each field or frame in which a change in luminance occurs in the display screen over a long period of time. The flicker can be made inconspicuous by using the liquid crystal molecule oscillation scanning for giving the above.

The contents are such that the amount of transmitted light by the dummy scanning performed in the first field or frame and the subsequent second field or frame is almost the same.

Secondly, since the change in the light amount is as slow as one field or one frame, dummy scanning is inserted at a time during which human vision can be averaged to complement the time interval.

Thirdly, the transmitted light amount by the cooperation of the dummy scanning and the selective scanning performed in the first field or frame and the subsequent second field or frame is set to the same amount as much as possible.

By using the above-mentioned three means, the display in the one-field or one-frame inversion drive in which the flicker reduction is difficult can be performed without failure.

[Brief description of drawings]

FIG. 1 is a waveform diagram showing an example of scanning in which dummy scanning is used in combination with 1F inversion scanning according to an embodiment of the present invention.

FIG. 2 is a graph showing frame frequency versus flicker subjective evaluation value in the case of performing the scan of FIG. 1 in comparison with the case of performing the scan of FIG.

3 is a graph showing the dummy voltage vs. flicker subjective evaluation value in the case of performing the scan of FIG. 1 in comparison with the case of performing the scan in FIG.

FIG. 4 is a cross-sectional view of a ferroelectric liquid crystal display panel that is an example of an application target of the present invention.

5 is a layout view of electrodes of the liquid crystal display panel of FIG.

FIG. 6 is a selection scanning waveform diagram in 1-frame inversion driving.

FIG. 7 is a diagram of a selective scanning waveform, an information signal waveform, and a dummy scanning waveform used in this embodiment.

FIG. 8 is a graph diagram of subjective evaluation of flicker when the absolute voltage with respect to the common voltage of the dummy waveform is changed in 1H inversion driving.

FIG. 9 is a graph chart of subjective evaluation of flicker when changing the number of dummy scanning lines and the frame frequency in the case of progressive scanning (1H inversion).

FIG. 10 is a waveform diagram showing a comparative example in which one-frame inversion driving is simply combined with selective scanning and dummy scanning waveforms.

FIG. 11 is a first scanning line selection waveform in the first frame of the present embodiment. It is a figure which shows the information signal of a dark information waveform, and those synthetic waveforms.

FIG. 12 is a first scan line selection waveform in the first frame of the present embodiment. It is a figure which shows the information signal of a bright information waveform, and those synthetic waveforms.

FIG. 13 is a first scanning line selection waveform in a second frame of this embodiment. It is a figure which shows the information signal of a dark information waveform, and those synthetic waveforms.

FIG. 14 is a first scanning line selection waveform in a second frame of this embodiment. It is a figure which shows the information signal of a bright information waveform, and those synthetic waveforms.

FIG. 15 is a first scan line dummy waveform of the first frame of the present embodiment. It is a figure which shows the information signal of a dark information waveform, and those synthetic waveforms.

FIG. 16 is a first scan line dummy waveform of the first frame of the present embodiment. It is a figure which shows the information signal of a bright information waveform, and those synthetic waveforms.

FIG. 17 is a 1F inverted dummy waveform. It is a figure which shows the information signal of a bright information waveform, and those synthetic waveforms.

FIG. 18 is a 1F inverted dummy waveform. It is a figure which shows the information signal of a dark information waveform, and those synthetic waveforms.

FIG. 19 is a graph of frame frequency vs. flicker subjective evaluation value in a scanning example in which dummy scanning is used in combination with the 1F inversion scanning of FIG. 13.

20 is a graph of a dummy voltage vs. flicker subjective evaluation value in a scanning example in which dummy scanning is used in combination with the 1F inversion scanning of FIG.

[Explanation of symbols]

10a: analyzer polarization plate, 10b: polarizer polarization plate, 11a: glass substrate, 11b: glass substrate, 12
a: transparent electrode, 12b: transparent electrode, 13a: insulating film, 1
3b: insulating film, 14a: alignment film, 14b: alignment film, 1
5: Ferroelectric chiral smectic liquid crystal, 16: Bead spacer, 1Ha: erase period, 1Hb: selection period,
I1 to 1960: information line, DM: dummy signal waveform, dt
1, dt2: period of pulses forming a selected waveform, K: information signal waveform, L: composite waveform of selected waveform and information signal waveform,
M: information signal waveform, MA: selected waveform, MB: selected waveform,
MC: Selected waveform, MD: Selected waveform, ME: Selected waveform, M
F: selected waveform, Ma: dummy waveform, Mb: dummy waveform,
Mc: dummy waveform, Md: dummy waveform, Me: dummy waveform, Mf: dummy waveform, md: dummy waveform, me: dummy waveform, mf: dummy waveform, N: composite waveform of selected waveform and information signal waveform, O: dummy Composite waveform of waveform and information signal waveform, P: Composite waveform of dummy waveform and information signal waveform, P1:
Reset pulse, P2: selection pulse, Q: composite waveform of selection waveform and information signal waveform, Q1: selection period, Q2: auxiliary period for canceling DC component, R: combination waveform of selection waveform and information signal waveform, SEL: selection signal waveform, SEG: information signal waveform, S1~S1024: scanning line, S: composite waveform dummy waveform and the information signal waveform, T: composite waveform dummy waveform and the information signal waveform, T ₁ ~T _13: horizontal scanning time , T ₂₅₅ ~ T
₂₆₀ : horizontal scanning period, V1, V2: selected waveform voltage, V
5, V6: Dummy waveform voltage, + VS, −VS: Information signal waveform voltage, Δt: Selection synchronization period.

Claims (7)

[Claims] 1. A display panel in which pixels are arranged in a matrix by a scan electrode group and an information electrode group, and a polarity of a voltage with respect to a common potential for each field or one frame of display on the display panel on the scan electrode. In a display device having a writing means for applying a selection signal that inverts the voltage and applying an information signal for causing the pixel to have a predetermined display state in at least one of the scanning electrodes in the non-selected state. A display device comprising means for applying a dummy signal for temporarily varying the amount of transmitted light of a pixel corresponding to the scanning electrode. 2. The dummy signal is one frame or one.
The display device according to claim 1, wherein the display device is inserted at intervals that can be averaged by human eyes without using the cooperation of selective scanning between fields. 3. The display device according to claim 1, wherein the dummy signal uses voltage waveforms of the same polarity over each frame period without inversion in units of one field or one frame. 4. The display device according to claim 1, wherein the dummy signals are collectively used over a plurality of horizontal scanning periods, and the horizontal scanning periods are even numbers. 5. The dummy signal is one frame or one frame.
2. The display device according to claim 1, wherein an average transmitted light amount when cooperating with selective scanning between fields is substantially equal to an average transmitted light amount during another one frame or one field. 6. The display device according to claim 1, wherein the pixel is made of liquid crystal. 7. The display device according to claim 6, wherein the liquid crystal is a ferroelectric liquid crystal.