JPH06314082A - Device for driving liquid crystal pannel and data conversion method used in the driving device - Google Patents

Abstract

PURPOSE:To simplify the constitution of a signal processing circuit for driving a simple matrix liquid crystal pannel and to reduce a cost. CONSTITUTION:By a conversion block 300, after the column vectors of the image data matrix of N rows M columns in an image data buffer memory 1 are divided into (n) of column vectors consisting of (m) pieces of data from the head successively, are made (n) of row vectors by displacing respectively, and the matrix (a) of (n) rows (m) columns is constituted, and is converted to a column signal matrix by performing the calculation of the product between the matrix (a) and an (n) dimension orthogonal matrix outputted by a matrix generation block 200 for the whole columns of the image data matrix. The column signal matrix is impressed to the signal side electrodes of a simple matrix liquid crystal display device 14 through a buffer memory 8, etc. By a distribution circuit 9, one row of the (n) dimension orthogonal matrix is expanded to one row of N dimension orthogonal matrix to be stored in a register 10 for scanning side voltage, and is impressed to the scanning electrodes of the liquid crystal display device 14 through a scanning side driver 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a liquid crystal panel using a simple matrix system and a data conversion method used for the drive device.

[0002]

2. Description of the Related Art In recent years, a display device such as a liquid crystal display device is an indispensable technology as a man-machine interface, and particularly in recent computer terminals and the like, a liquid crystal display device is indispensable from the viewpoint of downsizing. Has become. Among them, the simple matrix type liquid crystal display device is widely used because of its reasonable price and the like.

Conventionally, as a driving method of a simple matrix type liquid crystal display device, line-sequential scanning of scanning lines is used in accordance with the voltage averaging driving method. This method is mathematically considered as follows. That is, the number of scanning lines is N,
Assuming that the applied voltage of the selected scanning line is “1” and the applied voltage of the unselected scanning line is “0”, selecting one scanning line at each moment in turn means that N scanning lines of the liquid crystal panel are selected. When the direction in which the scanning electrodes are arranged is the row direction and the direction in which the time changes is the column direction, an N-th unit matrix is generated as a whole,
This is equivalent to driving each scanning line. Below, the rows of the matrix,
The definition of columns is made mathematically, and the definition of rows and columns in a liquid crystal panel of a simple matrix system is such that scanning lines correspond to rows and signal lines correspond to columns.

When this method is used in a high-speed liquid crystal panel, each scanning line becomes bright once for a frame and then becomes dark immediately, and as a result, the liquid crystal panel transmits a white state and a light does not pass. The contrast, which is the ratio of brightness in the black state, is considerably lower than expected. When used in a normal liquid crystal panel, this state is maintained for one frame or more when it becomes bright by an instantaneous large voltage pulse. Such a phenomenon is called a frame response.

Therefore, recently, the following driving method has been devised. It is a method of using an orthogonal matrix having “1” and “−1” as elements. The orthogonal matrix referred to here means a matrix in which the inner product of any two different row vectors among the row vectors forming the matrix is always “0”.

Among such orthogonal matrices, consider an Nth-order orthogonal matrix H ₀ suitable for the size of the image data matrix A of N rows and M columns corresponding to the image data of one frame, and consider these two matrices. By performing the multiplication, the column signal matrix B representing the temporal change of the voltage peak value of the column signal is created.

Next, the orthogonal matrix H ₀ is used for the matrix representing the temporal change of the drive signal of each scanning line of the liquid crystal panel, which is the unit matrix in the voltage averaging drive method. , "1", a voltage whose polarity is inverted is applied to the scan electrodes. That is, not line-sequential scanning,
This is equivalent to selecting all the scan lines at once. And 1
At time t when the frame period is divided into N equal parts, a voltage corresponding to the value of each element of the t-th row of the matrix H ₀ is applied to the scan electrodes, and at the same time, the value of each element of the t-th row of the column signal matrix B is applied. Is applied to each signal electrode. By doing so, the column signal matrix B is inversely transformed on the liquid crystal panel, and an effective voltage according to each element of the original image data can be applied to each pixel.

By increasing the number of scanning lines selected in this way and dispersing the effective voltage applied to each pixel within one frame, the voltage peak value is lowered as compared with the voltage averaging driving method of line-sequential scanning. be able to. From this point, there is an advantage that crosstalk and frame response can be reduced and image quality can be improved.

[0009] Incidentally, this method is based on Clifton, B. etc., "Har
dware Architectures for Video-Rate, Active Address
ed STN Displays, "Proceedings of the 12th Internat
ional Display Research Conference, pp.504-506, Oc
For more information on t.1992. and orthogonal matrices, see "Code theory", Hiroshi Miyagawa et al., published by Shokoido.

[0010]

However, as described above, in the case of simultaneously selecting all the scanning lines, there is a problem that a huge scale of arithmetic circuit is required to calculate the column signal.

The present invention solves the above-mentioned conventional problems. Each element is extended from a matrix consisting of binary values of "1" and "-1" and a unit matrix. Each element is "1". And a matrix consisting of three values of "0" and "-1" are calculated as "1" and "-".
To provide a data conversion method capable of reducing the scale of a calculation circuit for calculating a column signal by performing only a calculation of a binary matrix of "1", and a liquid crystal panel drive device using this conversion method. To aim.

[0012]

In order to achieve this object, the present invention provides an image data buffer memory for storing an image data matrix A of N rows and M columns input from the outside, and each element is 1 and -1. The matrix generating means for generating an n-th order orthogonal matrix X consisting of and the data of one column of the image data matrix A constitutes an n-row m-column matrix a in which the total number of data is N. The conversion means for converting the image data matrix A into the column signal matrix B by performing the calculation of the product of X and the matrix a for all columns of the image data matrix A, and the conversion data for storing the column signal matrix B A buffer memory, a liquid crystal display means using a simple matrix system, and an orthogonal matrix H, which is extended from the orthogonal matrix X and each element is composed of 1's, 0's, and -1, and a column signal matrix B to form a liquid crystal display means. It has the structure of the drive means to drive.

[0013]

According to the present invention, with the above configuration, the number of simultaneously selected scanning lines is reduced by using a matrix in which each element is a ternary value of 1, 0 and -1. The calculation of the matrix is performed only by the calculation of the matrix composed of the binary values of 1 and -1, whereby the scale of the arithmetic circuit for calculating the column signal can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a drive device for a liquid crystal panel showing a first embodiment of the present invention.

In FIG. 1, an image data buffer memory 1 stores image data of one frame (N rows and M columns) input from the outside as an image data matrix A, and the matrix memory 2 stores each element "1". And an Nth-order orthogonal matrix X having binary elements of “−1” and “−1” are stored. The row register 3 can read the elements of the matrix X stored in the matrix memory 2 on a row-by-row basis, and this operation is sequentially performed from the first row to the n-th row. The selector 4 distributes N pieces of data in one column of the image data matrix A stored in the image data buffer memory 1 in order from the beginning to m pieces of n-stage shift registers included in the shift register group 5. . That is, this means that the data of one column of the image data matrix A is divided into n column vectors consisting of m data in order from the beginning, and then transposed into n row vectors. , Is equivalent to forming an n-row m-column matrix a in which the total number of data is N, and the adjacent data in one shift register is m data separated in the original column vector. .

The selector 6 selects one of the m shift registers while the row register 3 holds one row vector, and the data of the selected shift register is sent to the arithmetic circuit 7 in parallel. The transfer operation is performed for all shift registers. Every time the arithmetic circuit 7 changes the shift register selected by the selector 6, the arithmetic circuit 7 calculates the inner product of the data transferred from the selector 6, that is, the column vector of the matrix a and the row vector of the row register 3 to obtain the matrix a Matrix X
Find the product of

In this operation, the orthogonal matrix X of the matrix memory 2 is used as the matrix of (Equation 3), and the column vector of the matrix A is (Equation 4).
The shift register group 5 consists of 8 elements such as
It is assumed that the shift register has two 4-stage shift registers. However, t at the left corner of (Equation 4) means transposition.

[0018]

[Equation 3]

[0019]

[Equation 4]

First, 4 obtained by rearranging row vectors
The matrix of rows and columns is as shown in (Equation 5).

[0021]

[Equation 5]

Here, the matrix of (Equation 5) and the matrix X (Equation 3)
If the matrix obtained from the product of and is like (Equation 6),

[0023]

[Equation 6]

The matrix of (Equation 6) is the matrix X of (Equation 3).
And the unit matrix Y of (Equation 7) and the column vector (Equation 10), which is the product of the matrix H of (Equation 9) obtained from the Kronecker product (Equation 8), and the column vector of (Equation 4), It turns out that it becomes equal to the rearranged one.

[0025]

[Equation 7]

[0026]

[Equation 8]

[0027]

[Equation 9]

[0028]

[Equation 10]

These series of operations are performed by M of the image data matrix A.
When all columns are performed, as a result, the column signal matrix B of N rows and M columns, which is the product of the matrix H and the image data matrix A, is created in column units and stored in the conversion data buffer memory 8. It For more information on this Kronecker product, see Code Theory, written by Hiroshi Miyagawa et al., Published by Shokoido.

Further, the distribution circuit 9 divides the scanning-side voltage register 10 capable of storing N pieces of data into m pieces, and considers a total of n groups (G _{0 to} G _n-1 ) at time t. , with r, s obtained from equation (11), in k-th group G _k, the data of s-th location of order n matrix X of r rows and k columns of elements, other G _k The data in the row register is distributed so that 0 is stored in the place. The scanning side driver 11 includes a scanning side voltage register 10
A scanning voltage is applied to the scanning electrodes of the simple matrix type liquid crystal display device 14 according to the data stored in. Thereby, at time t, a voltage corresponding to the value of each element in the t-th row of the N-th order matrix H can be virtually applied to the N scanning electrodes of the simple matrix liquid crystal display device 14. .

[0031]

[Equation 11]

On the other hand, the conversion data buffer memory 8 sequentially performs the operation of outputting each element of the column signal matrix B from the 1st row and the 1st column to the 1st row and the Mth column to the Nth row, and sends it to the D / A converter 12. , D / A converter 12 converts the sent digital value into an analog value and outputs it. Signal side driver 13
Is a voltage converted by the D / A converter 12 according to M analog values corresponding to one row of the column signal matrix B to M signal side electrodes of the simple matrix liquid crystal display device 14. Apply in parallel.

Among these constituent elements, the distribution circuit 9, the scanning side voltage register 10, the scanning side driver 11, the D / A converter 12, and the signal side driver 13 drive the simple matrix type liquid crystal display device 14. A drive block 100 is configured, and a matrix generation block 200 that generates the elements of the matrix X in units of one row is configured from the matrix memory 2 and the row register 3, and a selector 4, a register group 5, a selector 6, and an arithmetic circuit 7 are provided. From the above, a conversion block 300 for converting the image data matrix A into the column signal matrix B using the matrix H is configured.

As described above, according to the first embodiment, the image data buffer memory (image data buffer memory 1) for storing the image data matrix A of N rows and M columns input from the outside and each element is 1 N-th orthogonal matrix X consisting of 1 and -1
Generating means for generating (matrix generating block 200)
And the data of one column of the image data matrix A constitutes a matrix a of n rows and m columns in which the total number of data is N, and the product of the orthogonal matrix X and the matrix a is calculated by the image data matrix A For all columns of the image data matrix A to the column signal matrix B
Conversion means (conversion block 300) for converting into a column, a conversion data buffer memory (conversion data buffer memory 8) for storing the column signal matrix B, and a liquid crystal display means (simple matrix liquid crystal display device 14) using a simple matrix system.
And driving means (driving block 100) for driving the liquid crystal display means from the N-order orthogonal matrix H, which is extended from the orthogonal matrix X and each element is composed of 1, 0 and -1, and the column signal matrix B. Therefore, the number of simultaneously selected scanning lines is reduced by using a matrix in which each element is a ternary value of 1, 0 and -1 and 1 and 0.
By performing the calculation of the matrix of three values of −1 and −1 only by the calculation of the matrix of two values of 1 and −1, the scale of the calculation circuit for calculating the column signal can be reduced.

By changing the order of the row vectors of the matrix a composed of the column vectors of the image data matrix A, the matrix H consequently changes the order of the rows or columns of the m-dimensional unit matrix. The same effect can be obtained even if the Kronecker product of the matrix and the matrix X is obtained.

In addition, among the m shift registers of the shift register group 5, the data of a specific shift register is always calculated by changing the sign, so that the matrix H becomes a row or a column of the unit matrix of degree m. The same effect can be obtained even if the matrix multiplied by 1 and the Kronecker product of the matrix X are obtained.

Further, the matrix memory 2, the row register 3, the selector 4, the shift register group 5, the selector 6, the arithmetic circuit 7, and the distribution circuit 9 can also be realized by using a microcomputer, and the effect of the invention does not change. Absent.

Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 2, parts having the same functions as those in FIG.

The selector 20 has n stages of shift registers.
With respect to the shift register group 21 having one, N pieces of data in one column of the image data matrix A stored in the image data buffer memory 1 are stored in order from the beginning in consecutive m pieces of data in one shift register. Distribute as is done. That is, this means that the data of one column of the image data matrix A is divided into n column vectors consisting of m data in order from the beginning, and then transposed into n row vectors. , Is equivalent to forming a matrix a of n rows and m columns in which the total number of data is N.

Each shift register of the shift register group 21 performs cyclic shift by m-1 times while the row register 3 holds one row vector, and the column register 22 has n shift registers of the shift register group 21. Latch the data at the beginning position of the shift register of. That is, the column vector of the matrix a is latched in the column register 22.

Every time the column vector of the column register 22 is updated, the arithmetic circuit 7 calculates the inner product of the column vector consisting of n pieces of data of the column register 22 and the row vector of the row register 3 to obtain the matrix a. And the matrix X are calculated.

In the second embodiment, the matrix H consisting of three values "1", "0" and "-1" is formed from the selector 20, the register group 21, the column register 22 and the arithmetic circuit 7 as described above.
The conversion block 400 for converting the image data matrix A into the column signal matrix B is constructed by using and is used in place of the conversion block 300 of the first embodiment.

By setting the position of the data latched by the column register 22 to a position other than the head of the n shift registers, etc., the matrix H changes the order of the rows or columns of the m-th unit matrix. The same effect can be obtained even if the Kronecker product of the matrix and the matrix X is obtained.

Also, the selector 20 and the shift register group 2
The first and column registers 22 can also be realized by using a microcomputer, and the effect of the invention remains unchanged.

[0045]

As described above in detail, according to the present invention, simultaneous selection of scanning lines is performed by using a matrix in which each element is a ternary value of "1", "0" and "-1". Reduce the number of lines,
An operation for calculating a column signal by performing an operation of a matrix consisting of three values of “1”, “0” and “−1” only by an operation of a matrix consisting of two values of “1” and “−1”. The circuit scale can be reduced.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of a drive device for a liquid crystal panel according to a second embodiment of the present invention.

[Explanation of symbols]

 1 image data buffer memory 2 matrix memory 3 row register 4, 6, 22 selector 5, 21 shift register group 7 arithmetic circuit 8 conversion data buffer memory 9 distribution circuit 10 scanning side voltage register 11 scanning side driver 12 D / A converter 13 signal side driver 14 simple matrix type liquid crystal display device 22 column register 100 drive block 200 matrix generation block 300, 400 conversion block

Claims (7)

[Claims] 1. A column vector of a matrix A having N rows and M columns (M and N are natural numbers) is composed of n column vectors (m and n are natural numbers, and N = m × n) consisting of m pieces of data in order from the beginning. After dividing into n), each of them is transposed into n row vectors to form an n-row m-column matrix a in which the total number of data is N, and the n-order orthogonal matrix X and the matrix a By calculating the product of M with respect to the M columns of the matrix A, an m-th order square matrix consisting of all 0s except that there is only one 1 in each row and each column of the n-th order orthogonal matrix X A data conversion method for calculating a product of an N-order orthogonal matrix H obtained by expanding the matrix Y by the Kronecker product shown in (Equation 1) and the matrix A. [Equation 1] 2. The data conversion method according to claim 1, wherein the m-th order square matrix Y is an m-th order unit matrix. 3. An nth-order orthogonal matrix X is composed of binary values of 1 and −1 for each element, and an Nth-order orthogonal matrix H is ternary value of each element of 1 and 0 and −1. The data conversion method according to claim 1, comprising: 4. The data conversion method according to claim 1, wherein the matrix a is constructed by using m one-dimensional memories capable of storing n pieces of data. 5. The data conversion method according to claim 1, wherein the matrix a is constructed by using n one-dimensional memories capable of storing m pieces of data. 6. An image data buffer memory for storing an image data matrix A of N rows and M columns corresponding to a two-dimensional image input from the outside, matrix generation means for generating an orthogonal matrix X of order n, and the image. The column vector of the data matrix A is m from the beginning
After dividing into n column vectors of data,
By transposing each of them into n row vectors, an n-row m-column matrix a in which the total number of data is N is constructed.
The calculation of the product of the following orthogonal matrix X and the matrix a is performed using the matrix A
, The n-th order orthogonal matrix X
The conversion means for calculating the column signal matrix B which is the product of the Nth-order orthogonal matrix H and the image data matrix A, which are expanded from, the conversion data buffer memory for storing the column signal matrix B, and the simple matrix method Liquid crystal display means used, and a voltage corresponding to the value of each element of the t-th row of the N-order orthogonal matrix H at time t (t is an integer of 0 or more and less than N) when one frame period is divided into N equal parts. Is simultaneously applied to the scanning electrodes of the liquid crystal display means, and at the same time, a voltage corresponding to the value of each element in the t-th row of the column signal matrix B is applied to each signal electrode of the liquid crystal display means to drive the liquid crystal display means. A drive unit for a liquid crystal panel, comprising: a drive unit. 7. The driving means divides the N scanning electrodes of the liquid crystal display means into _n groups (G _{0 to} G _n-1 ) of continuous m scanning electrodes, and at time t. Using r and s obtained from (Equation 2), in the k-th (k is an integer of 0 or more and less than n) group G _k , the voltage corresponding to the value of the element at row r and column k of the matrix X is 6. The voltage according to the value of the element of each row of the matrix H is applied to the N scan electrodes by applying a voltage according to 0 to the scan electrodes other than the s-th scan electrode. 6. A liquid crystal panel drive device according to item 6. [Equation 2]