JPH096291A - LCD panel drive - Google Patents

Abstract

(57) [Abstract] [Purpose] In a simple matrix type liquid crystal panel drive device for simultaneously selecting a plurality of rows, noise appearing when a moving image is displayed is eliminated to improve image quality. [Structure] The image data memory 1 stores and outputs image data. The orthogonal matrix held and output by the matrix generation ROM 2 as the prime of the row signal is n rows l consisting of binary values of 1 and -1.
It is an orthogonal matrix in which an orthogonal matrix of columns is extended to N rows and L columns consisting of three values of 1, 0, and −1, and N / n− is repeated twice or more when all data of each row signal are output. All row signals are orthogonal to each other once or less. The inner product calculation circuit 3 generates a matrix R
The output data of the OM2 and the image data are calculated to output the column signal data. The column signal data memory 4 stores and outputs the column signal data. The driving block 200 drives the STN liquid crystal panel 10 by using the output data of the matrix generation ROM 2 as a row signal and the output data of the column signal data memory 4 as a column signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for a simple matrix type liquid crystal panel using a driving method for simultaneously selecting a plurality of rows.

[0002]

2. Description of the Related Art At present, liquid crystal panels are widely and commonly used as flat panel displays. One of the typical types thereof is an STN simple matrix type liquid crystal panel. After that, STN simple matrix type liquid crystal panel
Abbreviated as TN liquid crystal panel. This STN liquid crystal panel is shown in FIG.
As shown in FIG. 1, the liquid crystal layer 224 is sandwiched between two glass substrates (or simply called glass) 223. A row electrode 221 which is a plurality of striped transparent electrodes is provided on one glass 223 and a glass electrode 223 on the other side is provided.
Is a column electrode 222 which is also a plurality of striped transparent electrodes.
Are formed, and the row electrode 221 and the column electrode 2
22 have a perpendicular relationship to each other. Due to such a simple structure, the STN liquid crystal panel has an advantage that it can be produced at low cost. You can also display videos at video rates,
Currently, STN LCD panels with high-speed response are being developed,
The field of application is expanding.

However, in a conventional fast response STN liquid crystal panel, a selection voltage is applied to one row electrode only once in one frame period, and information of pixels on the row is supplied from a column electrode. When the sequential driving method is used, the contrast is significantly reduced. This phenomenon is explained in FIG. FIG.
2 (a) shows a row signal applied to one row electrode, FIG. 2 (b) shows a column signal applied to one column electrode, and FIG. 2 (c) shows a row electrode and a column signal. It is a difference signal between the signal shown in FIG. 9A and the signal shown in FIG. 7B applied to one pixel at the intersection of the electrodes. Since the signal in FIG. 10A is a row selection pulse, each row electrode is selected only once in one frame period in the conventional driving method. The liquid crystal having a high response speed in the liquid crystal layer 224 is driven by the signal shown in FIG.
It shows an optical response like the waveform shown in (d). Since the human eyes perceive it as on-luminance and off-luminance, which are indicated by the two broken lines in FIG. 3D, when the line-sequential driving method is used for a high-speed response liquid crystal, the contrast of the displayed image is Will fall. This phenomenon is called a frame response phenomenon.

Therefore, in recent years, a new driving method called a multiple-row simultaneous selection driving method has been proposed. This is a technique for simultaneously selecting a plurality of rows at a time to select one row a plurality of times during one frame period, thereby suppressing a frame response phenomenon. FIG. 13 shows that the frame response phenomenon is suppressed by the multiple row simultaneous selection driving method. FIG.
3, (a) is a row signal applied to one row electrode, (b) is a column signal applied to one column electrode, and (c) is a figure (a). 2) is a difference signal between the signal in FIG. As shown in (a) of the same figure, one row is repeatedly selected at equal intervals within one frame period.
The liquid crystal of the pixel driven by the signal of (c) shows an optical response like the waveform shown in FIG. In this way, a decrease in on-luminance and an increase in off-luminance are prevented, and high contrast can be obtained.

FIG. 14 shows an outline of a specific process of the multiple row simultaneous selection driving method. First, the row electrode 22
The row signal to 1 will be described. In the orthogonal matrix 231, each data is composed of binary values of 1 and −1 or ternary values of 1,0 and −1, and the inner product value of any two different column vectors among the column vectors forming the matrix is , A matrix that always becomes 0. The row driver 9 repeatedly applies a voltage proportional to the data of the orthogonal matrix 231 to the row electrode 221 as a row signal. Of the three values of such an orthogonal matrix, the voltages corresponding to 1 and −1 are the selection pulse for the row electrode 221. Therefore, 1− of one row vector of the orthogonal matrix 231
The row electrodes 221 are simultaneously selected by the total number of 1 and the total number of 1 and −1 of one column vector of the orthogonal matrix 231 is
One row electrode will be selected in one frame period.

Next, the column signal to the column electrode 222 will be described. The column signal data 233 which is the product of the orthogonal image 231 and the digital image data 232 for one frame displayed on the liquid crystal panel (-1 corresponds to ON and 1 corresponds to OFF).
Create The column driver 7 applies a voltage, which is proportional to each value of the column signal data, as a column signal to the column electrode 222.

The two signals are i-th (i is an integer of 0 or more and less than N) 1H period (1 frame period = 1H period × N)
In, the i-th row data of the orthogonal matrix 231 is applied to the row electrode, and the i-th row data of the column signal data 233 is applied to the column electrode. By doing so, an effective value voltage proportional to the image data to be displayed is accumulated in each pixel between both electrodes in one frame period. The liquid crystal layer 224 of each pixel transmits light according to the effective voltage between the row electrode 221 and the column electrode 222, so that an image is displayed on the liquid crystal panel.

Here, as a condition to be satisfied as the column signal data, there is a condition that the sum of squares of each data of one column vector must be constant. Considering the case of a binary image in which each image data is on (= -1) or off (= 1), the total number of 1 and -1 in one row vector is n.
(That is, the number of simultaneously selected lines is n), the orthogonal matrix of N rows and N columns is H, the column vector of image data (the number of data N) is x, and each data is x _i (= 1or-1) (1 ≦ i ≦ N), the column vector of column signal data (the number of data N) is y, and each data is y _i
Then, the sum S of the squares of each data of the column vector y is
It becomes like (Equation 1).

[0009]

[Equation 1]

As described above, in the case of the multiple-row simultaneous selection driving method, when the column signal data is output through one frame period, the sum of squares of each data of each column vector becomes a predetermined constant, and a normal image is obtained. Is displayed. As a document related to this driving method, "The color STN is obtained by obtaining an active driving method.
Liquid crystal approaches TFT ”, Nikkei Electronics 1994.9.
26th issue (No.618), pp171 to pp191 etc.

The structure of a conventional liquid crystal panel driving device that realizes this driving method will be briefly described with reference to FIG. In FIG. 15, the image data memory 1 stores digital moving image data transferred from the outside for one frame period, and N is the image data for the one frame period.
The image data matrix A of row M columns is output to the inner product calculating circuit 3 in units of one vertical column. The matrix generation ROM 14 holds a predetermined orthogonal matrix H of N rows and N columns, and repeatedly outputs the row vector data of the orthogonal matrix H to the inner product arithmetic circuit 3 and the row side voltage register 8.

The inner product calculating circuit 3 calculates the inner product of the row vector of the orthogonal matrix H output from the matrix generation ROM 14 and the column vector of the image data matrix A output from the image data memory 1. In the inner product calculating circuit 3, this calculation is performed by the orthogonal matrix H.
Of all the row vectors and the column vector of the matrix A are combined to calculate the column signal data matrix B of N rows and M columns.

The column signal data memory 4 stores the created matrix B and outputs it in units of rows. The D / A converter 6 is
The digital data sent from the column signal data memory 4 is converted into an analog value and output. The column driver 7
A voltage according to the analog data converted by the D / A converter 6 is applied to the M column electrodes of the STN liquid crystal panel 10.

On the other hand, the N pieces of data of the row vector of the orthogonal matrix H output from the matrix generation ROM 14 are latched in the row side voltage register 8 and the row driver 9 is stored in the row side voltage register 8. The voltage according to N data,
The voltage is applied to the N row electrodes of the STN liquid crystal panel 10. However, both the row driver 9 and the column driver 7 apply a voltage according to the data of the i-th row of the orthogonal matrix H and the matrix B to each electrode at time i within one frame period.

Of these components, the column vector of the digital image data transferred externally from the image data memory 1, inner product arithmetic circuit 3 and column signal data memory 4 and the orthogonal matrix output from the matrix generation ROM 14 A calculation block 100 for calculating an inner product of the row vector of H is configured, and the D / A converter 6, the column driver 7, the row-side voltage register 8 and the row driver 9 send a row signal and a column signal to the STN liquid crystal panel 10. A drive block 200 is configured to apply and.

In the liquid crystal panel driving device thus constructed, the image data memory 1 and the column signal data memory 4 have the following features. In the inner product arithmetic circuit 3,
In order to perform an operation on the data of one column of the image data matrix A and obtain one data of the column signal data matrix B,
Explaining the image data 232 in FIG. 14, the order of reading each data of the image data is x ₁₁ → x ₂₁ → x _31.
→ x ₄₁ → x ₁₂ → x ₂₂ →… → x ₄₄ However, when writing image data, the image data is input by raster scan, so x ₁₁ → x ₁₂ → x ₁₃ → x ₁₄ → x ₂₁ → x
₂₂ →… → x ₄₄

Therefore, the image data memory 1 is characterized in that reading is performed in the direction of FIG. 16B and writing is performed in the direction of FIG. 16A, and the data input order and output order are different. On the other hand, each data of the column signal data 233 is the inner product value of the column vector of the image data 232 and the row vector of the orthogonal matrix 231.
For one column vector, the row vector of the orthogonal matrix 231 is calculated by advancing from the first row to the last row in order, so that y ₁₁ → y ₂₁ → y ₃₁ → y ₄₁ → y ₁₂ → y ₂₂ → ... → y ₄₄ It will be created in such an order.

The column signal data thus created is sent to the column driver row by row as shown in FIG. 14, so that the order is y ₁₁ → y ₁₂ → y ₁₃ → y ₁₄ → y ₂₁ → y _22. →… → y
_{It looks} like ₄₄ . Therefore, in the column signal data memory 4, reading is performed in the direction of FIG.
It is performed in the direction of (b), and there is a feature that the data input order and the data output order are different.

Usually, as an orthogonal matrix,

[0020]

[Equation 2]

As shown in FIG. 17, an orthogonal matrix h of n rows and n columns (n is an integer of 2 or more) consisting of binary values of 1 and -1 is multiplied by m (m = N / n) both vertically and horizontally as shown in FIG. Expanded to 1,0,-
An orthogonal matrix H ₀ of N rows and N columns consisting of three values of 1 is used. One example of the orthogonal matrix h of 4 rows and 4 columns is shown in (Equation 3).

[0022]

(Equation 3)

The vertical direction of the orthogonal matrix H _{0 in} FIG. 17 corresponds to the time direction representing the output order of the row vector data, and the horizontal direction corresponds to the arrangement of the N row electrodes of the STN liquid crystal panel 10. The reason for using such an orthogonal matrix H ₀ will be described by comparing the orthogonal matrix h with the orthogonal matrix H ₁ obtained by the extension method as shown in FIG. Also in the case of FIG. 22, the vertical direction corresponds to the time direction indicating the output order of the row vector data, and the horizontal direction corresponds to the arrangement of the N row electrodes of the STN liquid crystal panel 10.

Here, the first column and the second column of the orthogonal matrix H ₀
The elements of the column vectors are shown in FIG. 23. Since the vertical direction corresponds to the time direction, the column vectors in FIG. 23 are output in order from the left. As an example, if n = 32 and m = 8, then (n-1) m + 1 (= 249) th h _n1 and h _n2 will be output. Hereinafter, description will be made assuming that n = 32, m = 8, N = 256. On the other hand, the vectors of the first column and the second column of the orthogonal matrix H ₁ are also shown in FIG. 24, but h _n1 and h _n2 are output as n (= 3
It is the 2) th, and is 0 after that. Since 1 and -1 correspond to the selection pulse, the orthogonal matrix H ₁ has a longer non-selection period. Therefore, if the orthogonal matrix H ₁ is used, the contrast is deteriorated due to the frame response phenomenon. The orthogonal matrix H ₀ is used for the above reasons.

For these two expansion methods, see 1993.
Year SDI Digest of Technical Papers, pages 89-92 (Optimum Row Function and Alg
orithms for Active Addressing, B.Clifton, D.Princ
e, B.Leybold, TJSchefer, ARConner and B.Greenbe
rg, 1993 SID Digest of Technical Papers, 89-92 (199
Detailed in 3)).

[0026]

However, when an image is displayed using the orthogonal matrix H ₀ as described above, the following two problems occur. First, the first problem will be described.
FIG. 18 is a diagram showing the squared value of each data of the column vector y in the output order in the case of a still image to which the same image data is repeatedly input. In FIGS. 18A and 18B, S _t4 ,
S _t8 represents the sum of the squares of the respective data of the column vector in one frame period up to the time points t4 and t8, respectively. As described above, the predetermined constant is set in each period of the Fth frame and the F + 1th frame (F is a natural number).

Since the concept of a frame does not exist in an actual liquid crystal panel, even in the column signal output during a period spanning two frames as shown in FIG. 18C,
The condition of (Equation 1) must be satisfied. When displaying a still image, the same column signal is output repeatedly, so
As shown in FIG. 18C, S _t6 across two frames is also a predetermined constant. Therefore, as shown in FIG. 19, S _t is always constant.

However, in the case of a moving image in which different image data is input for each frame, as shown in FIGS. 20 (a) and 20 (b), S _t4 is the _Fth frame and S is the S + _1th F + _1th frame. _{Although t8} is a predetermined constant,
S _t6 straddling two frames as shown in (c)
Is different from the predetermined constant. Therefore, as shown in FIG. 21, S _t becomes a predetermined constant only at the times of t0, t4, and t8, that is, every frame. For this reason, there is a problem in that the brightness of the entire line of the liquid crystal panel differs from the brightness to be displayed and appears as noise in the vertical direction. This phenomenon is called the splicing phenomenon.

Next, the second problem will be described. In the orthogonal matrix H ₀ , all column vectors are orthogonal to each other only when all the data of all column vectors are output, and a normal image is displayed only at this point. On the other hand, in the case of the orthogonal matrix H ₁ , all column vectors are orthogonal to each other at the time of outputting up to the n-th row, and are orthogonal to each other at the time of outputting up to the 2n-th row. When all the data of (1) have been output, all column vectors are orthogonal to each other m times in total. As a result, the STN liquid crystal panel 1
From the 1st row to the nth row of 0, a normal image is displayed when the nth row of all the column vectors of the orthogonal matrix H ₁ is output, and from the n + 1th row to the 2nth row, the orthogonal image is displayed. The time until a normal image is displayed is shorter than that of the orthogonal matrix H ₀ , such that a normal image is displayed when the 2nth rows of all column vectors of the matrix H ₁ are output. Become.

[0030] In other words, orthogonal matrix H ₀ than the orthogonal matrix H _1,
Since the non-orthogonal time is long and the normal image is displayed slowly, the data that should originally be displayed in another row appears to be displayed in another row. This phenomenon is called a ghost. However, since it is difficult to use the orthogonal matrix H ₁ that causes a decrease in contrast, there is a problem that ghost removal and high-contrast image display are not compatible.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a driving device for a liquid crystal panel that suppresses splicing and ghosts and displays a high-contrast image.

[0032]

In order to achieve this object, the present invention has, as a first structure, a simple matrix type ST.
An N liquid crystal panel and an orthogonal matrix that is a prime element of row signals, and is m-more than twice when all data of each row signal are output.
Approximately once or less, a matrix generating means for holding and outputting data of a matrix in which all row signals are orthogonal to each other, and an operation for calculating output data of the matrix generating means and image data transferred from the outside to output column signal data Means for driving the STN liquid crystal panel by generating row signals from the output data of the matrix generating means and column signals from the output data of the calculating means.

As a second configuration, a simple matrix STN liquid crystal panel and an orthogonal matrix which is a prime of row signals are provided at least twice and m-1 times at the time when all the data of each row signal are output. Hereinafter, matrix generating means for holding and outputting data of a matrix in which all row signals are orthogonal to each other, and calculating means for calculating output data of the matrix generating means and image data transferred from the outside and outputting column signal data. , A frame frequency conversion memory that stores column signal data and repeatedly outputs all stored data a plurality of times, and a row signal is generated from the output data of the matrix generation means, and a column signal is generated from the output data of the frame frequency conversion memory. It has a structure with a driving means for driving the STN liquid crystal panel.

As a third structure, a simple matrix type STN liquid crystal panel and an orthogonal matrix which is a prime of the row signals are provided at least twice m-1 times when all the data of each row signal are output. Hereinafter, matrix generating means for holding and outputting data of a matrix in which all row signals are orthogonal to each other, and calculating means for calculating output data of the matrix generating means and image data transferred from the outside and outputting column signal data. , The frame frequency conversion memory that stores the column signal data and repeatedly outputs all the stored data multiple times, and the column signal data that the frame frequency conversion memory outputs multiple times, the average of multiple times is the original data. The data precision conversion means for changing the precision of each data of the column signal data to output the same and the row signal from the output data of the matrix generation means for the output of the data precision conversion means. It has a configuration and a driving means for driving the STN liquid crystal panel generates a column signal, respectively from the data.

[0035]

With the first, second, and third configurations described above, the present invention can suppress the splicing phenomenon and the ghost and at the same time suppress the frame response phenomenon to display a high-contrast image. it can. Also, the third
With the above configuration, the requirement for the number of output voltage levels of the column driver can be reduced.

[0036]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a liquid crystal panel drive device showing an embodiment of the present invention. In FIG. 1, parts having the same functions as those of the conventional example shown in FIG.
The same numbers are assigned and the description is omitted.

In FIG. 1, the matrix generation ROM 2 obtains an orthogonal matrix h consisting of two binary values of 1 and -1, as shown in (Equation 2), which is obtained by the extension method of FIG. −
The data of the orthogonal matrix H ₂ consisting of three values of 1 is held, and the data of the row vector of the orthogonal matrix H ₂ is repeatedly output to the inner product arithmetic circuit 3 and the row side voltage register 8 in order. The orthogonal matrix H ₂ of FIG. ₂ corresponds to the i-th row of the orthogonal matrix H ₁ of FIG.
It is obtained by rearranging on the i'th line expressed by.

[0038]

(Equation 4)

The characteristics of the orthogonal matrix H ₂ extended in FIG. 2 will be described. First, as in FIGS. 17 and 22, FIG.
The vertical direction of the orthogonal matrix H ₂ corresponds to the time direction representing the output order of the row vector data, and the horizontal direction corresponds to the arrangement of N row electrodes of the STN liquid crystal panel 10. Orthogonal matrix H
_In the case of ₂ , all the column vectors are orthogonal to each other once the data up to the N / 2th row of all the column vectors are output, and
Once the data up to the row is output, all column vectors are orthogonal to each other again. As a result, the normal image is displayed in the upper half of the STN liquid crystal panel in the first half of the one frame period, and the normal image is displayed in the lower half of the lower half of the STN liquid crystal panel.
Therefore, since a normal image is displayed in a shorter time than using the orthogonal matrix H ₀ , the orthogonal matrix H ₂ can remove ghosts more than the orthogonal matrix H ₀ .

Further, the orthogonal matrix H ₂ is ₂ in one frame period.
Since all column vectors are orthogonal to each other and half the image data of the entire screen is displayed in the half period of one frame period, a predetermined constant (= nN) shown in (Formula 1) shown in the conventional example is displayed. Half of the data will be output twice in one frame period. FIG. 3 is a diagram showing the squared values of each data of the column vector y when a moving image is displayed, in the order of output.
Similar to FIG. 8, FIGS. 3A and 3B show a predetermined constant in the Fth and F + 1th frames.

However, in the case of the orthogonal matrix H ₂ , the sum of the squares of the data of the column vectors y in the first half and the second half is both half of the predetermined constant, so that two frames as shown in FIG. S _t6 across the _distance also becomes a predetermined constant. 4 is shown in FIG.
Similar to 9, it shows the sum of squares of each data of the column vector y in one frame period up to a certain time, and t0, t2, t
4, t6, at time t8 S _t indicates that a predetermined constant. As described above, in the case of the orthogonal matrix H ₂ , since S _t becomes a predetermined constant in a shorter time than in the case of the orthogonal matrix H ₀ , it is possible to suppress the splicing phenomenon.

Further, FIG. 5 shows the elements of the vectors of the first column and the second column of the orthogonal matrix H ₂ , but since the vertical direction corresponds to the time direction, the column vectors of FIG. Are output in order. Therefore, in the orthogonal matrix H ₂ , the maximum number of times 0 is continuously output in each column vector is N- (n-1) m / 2-1 (= 131), whereas the orthogonal matrix H ₂ is In H ₁ , the maximum is Nm (= 224), so that the orthogonal matrix H ₂ can suppress deterioration in contrast more than the orthogonal matrix H ₁ .

As described above, the orthogonal matrix H ₂ suppresses the ghost and the splicing phenomenon, and enables high contrast image display. As described above, the first aspect of the present invention
According to the embodiment, the STN liquid crystal panel of the simple matrix type (STN liquid crystal panel 10) and the matrix generating means (matrix generating ROM 2) for holding and outputting the data of the orthogonal matrix H _2.
And an arithmetic means (arithmetic block 100) for arithmetically operating the output data of the matrix generating means and the image data transferred from the outside to output column signal data, and a row signal from the output data of the matrix generating means for the arithmetic means. A driving unit (driving block 200) configured to generate a column signal from the output column signal data and drive the STN liquid crystal panel, suppresses a splicing phenomenon and a ghost, and at the same time, can display a high-contrast image. .

It should be noted that the image data memory 1 and the column signal data memory 4 do not handle the image data of one frame, but handle the image data of one field or the like, and the same effect is obtained. Obtained and not limited to the examples. Further, the orthogonal matrix H ₂ is not limited to the embodiment, as long as all the column vectors are orthogonal to each other a number of times 2 times or more and m−1 times or less when all the data of all column vectors are output.

Further, when the inner product calculating circuit 3 calculates the inner product of the row vector of the image data and the row vector of the orthogonal matrix H ₂ instead of the column vector of the image data, the input / output of the image data and the column signal data is performed. Even if it is not necessary to change the order and the image data memory 1 and the column signal data memory 4 are unnecessary, the same effect can be obtained, and the present invention is not limited to the embodiment.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. FIG. 6 is a block diagram of a drive device for a liquid crystal panel showing an embodiment of the present invention. 6, parts having the same functions as those in FIGS. 1 and 15 are designated by the same reference numerals and the description thereof will be omitted. The frame frequency conversion memory 5 has one input port and two output ports and can control each address separately, and the column signal data memory 4 outputs in the direction of FIG. 16 (a). Column signal data matrix B of N rows and M columns for one frame
After storing, all data are output to the D / A converter 6 R times (R is an integer of 2 or more) in the same order as the input order. Hereinafter, R will be described as 2.

The matrix generation ROM 13 is the matrix generation ROM 2
Similarly, the data of the orthogonal matrix H ₂ is held and the data is repeatedly output row by row, but the row side voltage register 8
Is output at a speed R times (= 2 times) that of the matrix generation ROM 2. Since the same image is displayed twice by the matrix generation ROM 13 and the frame frequency conversion memory 5, the frame frequency of the displayed image is
It is R times (= 2 times) that of the first embodiment.

The operation of the frame frequency conversion memory 5 will be described with reference to FIG. The input port inputs the column signal data output from the column signal data memory 4 in the order of FIG. The output port 1 starts outputting only the data in the odd rows when the input port inputs about half the total data, and the output port 2 starts outputting only the data in the even rows at the same time.

In this case, as a condition for repeatedly outputting the column signal data for one frame twice in the order of input,
There are two things. The first is that the input timing of the Nth row data of the Fth frame at the input port is the output port 2
Must be earlier than the output timing of the same data (Nth row data of the Fth frame). Second, the input timing of the first row data of the F + 1th frame at the input port is That is, it is always later than the second output timing of the first row data of the frame. In order to satisfy these two conditions, the vertical blanking period is effectively used.

FIG. 8 is a view showing the squared value of each data of the column vector y when a moving image is displayed, in the order of output, and FIG. 9 is a column vector y for one frame period up to a certain time point. The total sum of squares of each data is shown. in this case,
Since the frame frequency is doubled by the matrix generation ROM 13 and the frame frequency conversion memory 5, 1 in FIG.
The column signal data for one frame is output twice in one frame period. Therefore, as shown in FIG. 9, t0, t
1, t2, t3, t4, t5, t6, t7, becomes S _t is a predetermined constant at the time of t8, it has become a predetermined constant in shorter time than FIG. Therefore, the splicing phenomenon can be suppressed more than in the first embodiment.

As described above, according to the second embodiment of the present invention, the simple matrix type STN liquid crystal panel (STN liquid crystal panel 10) and the matrix generating means (matrix for holding and outputting the data of the orthogonal matrix H ₂ ). A generation ROM 2), a calculation means (calculation block 100) for calculating the output data of the matrix generation means and the image data transferred from the outside to output column signal data, and storing and storing the column signal data for one frame. The frame frequency conversion memory (frame frequency conversion memory 5) that repeatedly outputs all the data in the order of input, and the row signal from the output data of the matrix generating means and the column signal from the output data of the frame frequency conversion memory. The driving means (driving block 200) for respectively generating and driving the STN liquid crystal panel suppresses the splicing phenomenon and the ghost. Then at the same time, it is possible to display an image of high contrast.

The image data memory 1, the column signal data memory 4, and the frame frequency conversion memory 5 do not handle image data for one frame but image data for one field. Even if it does so, the same effect can be obtained, and it is not limited to the embodiment. In addition, the number of repeated outputs R of the frame frequency conversion memory 5 is
If it is 3 or more, there is no problem and the same or higher effect can be obtained.

Further, since the matrix generation ROM 13 and the frame frequency conversion memory 5 shorten the time until the frame frequency is multiplied by R and a normal image is displayed, the orthogonal matrix H ₂ is used instead of the orthogonal matrix H _2. The same effect can be obtained by using the matrix H ₀ . Further, by making the frame frequency R times by the matrix generation ROM 13 and the frame frequency conversion memory 5, the non-selection period can be shortened even if the orthogonal matrix H ₁ is used, so that the frame response phenomenon is suppressed and high. A contrast image can be displayed.

Furthermore, when the inner product calculating circuit 3 calculates the inner product of the row vector of the image data and the row vector of the orthogonal matrix H ₂ instead of the column vector of the image data,
Even when the input / output order of the image data and the column signal data does not have to be changed and the image data memory 1 and the column signal data memory 4 are unnecessary, the same effect can be obtained, and the present invention is not limited to the embodiment.

(Third Embodiment) A third embodiment of the present invention will be described below with reference to the drawings. FIG. 10 is a block diagram of a liquid crystal panel drive device showing an embodiment of the present invention. 10, parts having the same functions as those in FIG. 1, FIG. 6 and FIG.

The data precision conversion circuit 11 uses the frame frequency
D-bit data output from the number conversion memory 5
Is converted to D-d bit precision and output. This d
The frame frequency conversion memory 5 repeats data twice.
Since it outputs the data, it becomes 1 (2 ^d= 2), data accuracy change
The conversion circuit 11 converts the D-bit data into the D-1 bit data.
Output as data.

Table 1 shows the relationship between the input data and the output data of the data precision conversion circuit 11. (Table 1)
In, the LSB of the output data is always 0, and the average of the two output data is the input data.

[0058]

[Table 1]

The D / A converter 12 converts the digital data sent from the data precision conversion circuit 11 into an analog value and outputs it. In the D / A converter 12, the output data of the data precision conversion circuit 11 is digital data that is 1 bit less than the output data of the frame frequency conversion memory, and therefore the number of output signal levels is half that of the D / A converter 6. Can be configured with.

Since the same image is displayed twice and the frame frequency is doubled by the matrix generation ROM 13 and the frame frequency conversion memory 5, the data precision conversion circuit 11 and the D / A converter 12 are used. Then, even if the accuracy of the data is reduced by one bit, the average of the output data of the two times becomes the same as the data to be originally output. Therefore, normal FR
The feature is that there is no flicker unlike C (frame rate control).

Among these components, the D / A converter 12
, Column driver 7, row side voltage register 8 and row driver 9
A drive block 300 for applying a row signal and a column signal to the STN liquid crystal panel 10 is configured from the above. As described above, according to the third embodiment of the present invention, the STN liquid crystal panel of the simple matrix type (STN liquid crystal panel 10) and the matrix generation means (matrix generation ROM 2) for holding and outputting the data of the orthogonal matrix H _2. And arithmetic means (arithmetic block 100) for arithmetically operating the output data of the matrix generating means and the image data transferred from the outside to output the column signal data, and all the data stored and storing the column signal data for one frame. Of the frame frequency conversion memory (memory 5 for frame frequency conversion) that repeatedly outputs twice in the order of input, and each data of the column signal data output twice by the frame frequency conversion memory is the original data of two times. Data precision conversion means that changes the precision of each data of the column signal data so as to be the same and outputs it, and row signals from the output data of the matrix generation means And a driving means (driving block 300) for driving the STN liquid crystal panel by generating a column signal from the output data of the switching means, and suppressing a splicing phenomenon and a ghost and displaying a high-contrast image. Moreover, the demand for the output level of the D / A converter can be reduced.

The image data memory 1, the column signal data memory 4, and the frame frequency conversion memory 5 do not handle image data for one frame, but image data for one field. Even if it does so, the same effect can be obtained, and it is not limited to the embodiment. Further, the same effect can be obtained by replacing the column driver 7 with a column driver which has a D / A converter and can input digital data which is output data of the data precision conversion circuit 11.

In the repeated output count 2 ^d of the frame frequency conversion memory 5, the average of 2 ^d times of the output data of the data precision conversion circuit 11 is the same as the output data of the frame frequency conversion memory 5 even when d is 2 or more. Then, the same effect can be obtained. Further, when the inner product arithmetic circuit 3 calculates the inner product of the row vector of the image data and the row vector of the orthogonal matrix H ₂ instead of the column vector of the image data, the input / output order of the image data and the column signal data is changed. The same effect can be obtained even when the image data memory 1 and the column data memory 4 are unnecessary, and the present invention is not limited to the embodiment.

[0064]

As described above in detail, according to the first configuration of the present invention, the STN liquid crystal panel of the simple matrix type and the matrix generating means for holding and outputting the data of the orthogonal matrix H ₂ . STN liquid crystal panel for calculating a row signal from the output data of the matrix generating means, and a column signal from the output data of the matrix generating means. It is possible to suppress the splicing phenomenon and the ghost and display a high-contrast image at the same time.

Further, according to the second configuration, the STN liquid crystal panel of the simple matrix type, the matrix generating means for holding and outputting the data of the orthogonal matrix H ₂ , and the calculation of the output data of the matrix generating means and the image data. To output the column signal data, the frame frequency conversion memory that stores the column signal data and repeatedly outputs all the stored data a plurality of times in the order of input, and the row signal from the output data of the matrix generation unit to the frame signal. It is composed of driving means for respectively generating column signals from the output data of the frequency conversion memory and driving the STN liquid crystal panel, and it is possible to suppress a splicing phenomenon and a ghost and display a high-contrast image.

Further, according to the third configuration, the STN liquid crystal panel of the simple matrix type, the matrix generating means for holding and outputting the data of the orthogonal matrix H ₂ , and the calculation of the output data of the matrix generating means and the image data. And a column frequency signal output from the frame frequency conversion memory that outputs a plurality of column signal data, a column frequency conversion memory that stores the column signal data and repeatedly outputs all the stored data in the order of input Data precision conversion means for changing the precision of each data of the column signal data so that the average of a plurality of times of data becomes the same as the original data, and a row signal from the output data of the matrix generation means, Drive means for driving the STN liquid crystal panel by generating a column signal from the output data of the data precision conversion means, respectively, and a splicing phenomenon and a ghost At the same time inhibiting, can display an image of high contrast, also can reduce the requirements for the output level of the D / A converter.

[Brief description of drawings]

FIG. 1 is a block diagram of a drive device for a liquid crystal panel according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an extension method of an orthogonal matrix for reducing splicing phenomenon and ghost.

FIG. 3 is a time-varying waveform diagram of a value obtained by squaring the column signal data applied to one column electrode.

FIG. 4 is a time-varying waveform diagram of a value obtained by moving and averaging a value obtained by squaring the column signal data applied to one column electrode within a window of one frame period width.

FIG. 5 is a diagram showing first and second column vectors of the expansion method of the present invention and their output order.

FIG. 6 is a block diagram of a liquid crystal panel drive device according to a second embodiment of the present invention.

FIG. 7 is a timing chart of input / output data of the frame frequency conversion memory 5.

FIG. 8 is a time-varying waveform diagram of the squared value of column signal data applied to one column electrode.

FIG. 9 is a time-varying waveform diagram of a value obtained by performing a moving average of a value obtained by squaring the column signal data applied to one column electrode within a window of one frame period width.

FIG. 10 is a block diagram of a drive device for a liquid crystal panel in a third embodiment of the present invention.

FIG. 11 is a structural diagram of an STN liquid crystal panel.

FIG. 12 is a drive waveform diagram and an optical response waveform diagram when a conventional line-sequential selection drive method is used.

FIG. 13 is a drive waveform diagram and an optical response waveform diagram when the conventional multiple-row simultaneous selection drive method is used.

FIG. 14 is a diagram showing the concept of the multiple row simultaneous selection drive method.

FIG. 15 is a block diagram of a conventional liquid crystal panel drive device.

FIG. 16 is a diagram showing directions of writing and reading of image data in a driving method for simultaneously selecting a plurality of rows.

FIG. 17 is a diagram showing a conventional orthogonal matrix expansion method.

FIG. 18 is a time-varying waveform diagram of a value obtained by squaring the column signal data applied to one column electrode when displaying a still image.

FIG. 19 is a time-varying waveform diagram of a value obtained by moving the average of a value obtained by squaring the column signal data applied to one column electrode during still image display in a window having a width of one frame period.

FIG. 20 is a time-varying waveform diagram of the squared value of column signal data applied to one column electrode when displaying a moving image.

FIG. 21 is a time-varying waveform diagram of a value obtained by moving and averaging a value obtained by squaring the column signal data applied to one column electrode when displaying a moving image within a window having a width of one frame period.

FIG. 22 is a diagram showing a conventional orthogonal matrix expansion method.

23 is a diagram showing first and second column vectors of the extension method of FIG. 17 and their output order.

FIG. 24 is a diagram showing first and second column vectors of the extension method of FIG. 22 and their output order.

[Explanation of symbols]

 1 image data memory 2 matrix generation ROM 3 inner product arithmetic circuit 4 column signal data memory 5 frame frequency conversion memory 6 D / A converter 7 column driver 8 row side voltage register 9 row driver 10 STN liquid crystal panel 11 data accuracy Conversion circuit 100 Conversion block 200 Drive block

Claims (7)

[Claims] 1. A matrix type liquid crystal panel in which a liquid crystal responsive to an effective voltage is sandwiched between a row electrode and a column electrode, and data serving as a source of a row signal for driving the row electrode, n rows and 1 columns. By extending the orthogonal matrix of (n and l are integers of 2 or more) to N rows and L columns (N = n × m, L = l × m, m is an integer of 2 or more), all of the row signals can be obtained. At the time when the data is output, the row signal is held at least twice and not more than m-1 times, and all the row signals hold and output the data of the orthogonal matrix, and the output data of the matrix generating means and the external transfer. An arithmetic means for performing an arithmetic operation with the image data to output column signal data as a prime of a column signal for driving the column electrode, and a row signal from the output data of the matrix generating means, and an output data of the arithmetic means. Generating each of the column signals to drive the liquid crystal panel Driving device for a liquid crystal panel having a motion means. 2. A matrix type liquid crystal panel in which a liquid crystal responsive to an effective voltage is sandwiched between a row electrode and a column electrode, and an orthogonal matrix data which is a source of a row signal for driving the row electrode is held and output. Matrix calculating means for calculating the output data of the matrix generating means and image data transferred from the outside, and calculating column signal data which is a source of column signals for driving the column electrodes; A frame frequency conversion memory that stores a predetermined amount of the column signal data output from the computing unit and repeatedly outputs all stored column signal data a plurality of times, and the row signal from the output data of the matrix generating unit. A driving device for driving the liquid crystal panel by generating the column signals from the output data of the frame frequency conversion memory. 3. A matrix type liquid crystal panel in which a liquid crystal responsive to an effective value voltage is sandwiched between a row electrode and a column electrode, and data serving as a source of a row signal for driving the row electrode, n rows and 1 columns. By extending the orthogonal matrix of (n and l are integers of 2 or more) to N rows and L columns (N = n × m, L = l × m, m is an integer of 2 or more), all of the row signals can be obtained. At the time when the data is output, the row signal is held at least twice and not more than m-1 times, and all the row signals hold and output the data of the orthogonal matrix, and the output data of the matrix generating means and the external transfer. An arithmetic means for performing arithmetic operation with the image data and outputting column signal data as a prime of a column signal for driving the column electrode, and a predetermined amount of the column signal data output from the arithmetic means are stored. Frame cycle that repeatedly outputs the stored all column signal data multiple times A liquid crystal panel including a number conversion memory and a drive unit for driving the liquid crystal panel by generating the row signal from the output data of the matrix generation unit and the column signal from the output data of the frame frequency conversion memory. Drive. 4. The orthogonal matrix which is output from the matrix generating means and which is a prime element of the row signal is extended by using m orthogonal matrices of n rows and 1 columns consisting of binary values of 1 and -1, 1 and 0 and-. It is an orthogonal matrix of N rows and L columns consisting of three values of 1 and is an orthogonal matrix in which all row signals are orthogonal to each other at least twice and at most m-1 times at the time when all the data of each row signal are output. The drive device for a liquid crystal panel according to claim 1. 5. A matrix type liquid crystal panel in which a liquid crystal responsive to an effective voltage is sandwiched between a row electrode and a column electrode, and an orthogonal matrix data serving as an element of a row signal for driving the row electrode is held and output. Matrix calculating means for calculating the output data of the matrix generating means and image data transferred from the outside, and calculating column signal data which is a source of column signals for driving the column electrodes; A frame frequency conversion memory that stores a predetermined amount of the column signal data output from the arithmetic unit and repeatedly outputs the stored all column signal data a plurality of times, and the frame frequency conversion memory outputs a plurality of times. Data precision conversion means for outputting the respective data of the column signal data by changing the precision of the respective data of the column signal data so that the average of the plurality of times becomes the same as the original data, and the matrix. A driving device for a liquid crystal panel, comprising: driving means for driving the liquid crystal panel by generating the row signal from the output data of the generating means and the column signal from the output data of the data precision converting means. 6. The data precision conversion means inputs D-bit (D is an integer of 3 or more) digital data, and the average value of 2 ^d times (d is an integer of 2 or more and less than D) is the D-bit digital data. 6. The liquid crystal panel drive device according to claim 5, wherein D-d bit digital data to be data is output ^2d times. 7. The calculation means calculates an image data memory for storing and outputting a predetermined amount of image data transferred from the outside, a calculation of the output data of the matrix generation means and the image data, and a column signal. 4. An inner product calculating means for outputting data, and a column signal data memory for storing and outputting a predetermined amount of the column signal data.
Alternatively, the liquid crystal panel driving device according to item 5.