JPH0689073A - Active matrix type liquid crystal display device - Google Patents

Abstract

PURPOSE:To correct a visual angle with practicability by varying correction multilevel voltage. CONSTITUTION:An impressed voltage correcting means 14 includes a holding means 17 holding the basic correction factor of each number or every representative number of a scanning bus line, and adjusting parts 16 and 19 for additively and subtractively adjusting the largeness of an already adjusted correction factor generated based on the basic correction factor, and corrects display voltage V0-VN-1 impressed on the picture element electrode of a liquid crystal cell 10 or common voltage VC impressed on the common electrode of the liquid crystal cell are corrected by using the already adjusted correction factor additively and subtractively adjusted by the adjusting part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device, and more particularly to a technique for correcting variation in brightness and darkness in a vertical direction of a liquid crystal panel caused by a difference in viewing angle.

[0002]

2. Description of the Related Art FIG. 11 is a block diagram of a conventional liquid crystal display device, which is a thin film transistor (TFT).
2 is an example of an active matrix type display device having an anistor) array. In FIG. 11, reference numeral 1 is a display data generating source (for example, a personal computer) that generates digital display data, a transfer clock (pixel clock) Ck, a horizontal synchronizing signal HS, a vertical synchronizing signal Vs, and the like. The liquid crystal display device 2 is
A liquid crystal panel 3, a scan bus driver 4, and a data bus driver 5 are provided, and a power supply circuit 6 for scanning is provided.
A power supply circuit 7 for data and a power supply circuit 8 for common are provided. Here, the liquid crystal panel 3 is connected to n data bus lines (typically DB ₁ ) and m scan bus lines (typically SB ₁ ) and the intersections of the respective data bus lines and the scan bus lines. The liquid crystal cell includes n × m liquid crystal cells (typically M ₁ ) and when a predetermined voltage (gate-on voltage V _ON ) is applied to the scan bus line SB ₁ , the TFT of the liquid crystal cell M ₁ is turned on. and a pixel electrode G ₁ of the data bus lines DB ₁ and the liquid crystal cell M ₁ is connected, the display is applied to the data bus line DB ₁ voltage V _D
And the voltage of the common electrode C (constant voltage; so-called common voltage V _C ) depending on the potential difference between the two electrodes G ₁ , C.
It is generated in the liquid crystal material in between to obtain the brightness according to the display data.

The display voltage V _D applied to the data bus line DB ₁ is _one of multi-level voltages (hereinafter referred to as reference voltage) generated by the power supply circuit 7 for data, and corresponds to the gradation of the pixel. It was chosen by. For example, when the liquid crystal display device 2 displays N gradations, the reference voltages are N kinds from V _{0 to} V _N−1 . V ₀ corresponds to a white level (or black level), V _N-1 corresponds to a black level (or white level), and the divided voltages V _{1 to} V _N-2 between them correspond to a white level. Corresponds to the halftone between black and black levels.

By the way, it is known that the transmittance characteristic of liquid crystal changes depending on the viewing angle (viewing angle φ). 12
3 is a graph showing the relationship between the brightness (corresponding to the transmittance) and the viewing angle φ for one pixel of the liquid crystal panel. Now, assuming that the applied voltage of the liquid crystal cell is, for example, 3 V, the pixel is looked down (φ = 0 °) compared to when it is viewed from the front (φ = 0 °).
At −30 °, it looks brighter, and at the same time when looking up from the front, it looks darker (φ = + 30 °). That is, there is a problem that the brightness of the liquid crystal panel in the vertical direction becomes non-uniform, which is an obstacle particularly when a large-screen liquid crystal panel having a large viewing angle φ is produced. A similar problem occurs in the left-right direction of the liquid crystal panel, which is generally improved by using a deflector, for example.

As a solution to the above-mentioned problems, the present applicant has previously proposed an "active matrix type liquid crystal panel drive circuit" (Japanese Patent Application No. 4-162820, filed on Jun. 22, 1992). According to the technology of this prior application, the corrected gradation voltage of N gradations stored in the memory is read for each position of the scan bus line, and the read corrected gradation voltage is used to select the selected gradation corresponding to the display data. It is intended to correct the voltage.

According to this, for example, for the scan line located above the liquid crystal panel (position to look up), the correction gradation voltage in the "forward direction" is applied, while on the other hand, to the position below the liquid crystal panel (position to look down). By setting the correction grayscale voltage in the “negative direction” for the scan line to be), for example, the characteristic line of φ = −30 ° and the characteristic line of φ = + 30 ° of FIG. It is possible to make it close to the characteristic line, and to make the brightness in the vertical direction "when facing the liquid crystal panel" uniform.

[0007]

The technique of the prior application is as follows.
In short, the correction gradation voltage that makes the luminance in the vertical direction uniform is obtained while the relationship between the liquid crystal panel and the line of sight is kept "constant", and the correction gradation voltage is stored in the memory. However, since the line of sight when the liquid crystal panel is actually used does not always match the line of sight when the above setting is made, the corrected gray scale voltage may become inappropriate, resulting in poor practicality. [Object] Therefore, an object of the present invention is to provide a practical viewing angle correction technique by making the correction gradation voltage variable.

[0008]

In order to achieve the above-mentioned object, the present invention sequentially selects the scan bus lines of the liquid crystal panel in synchronism with the horizontal scanning signal, as shown in the principle diagram of FIG. The scan bus driver that applies a gate-on voltage to the scan canvas line and the pixel data of multi-gradation expression are input in synchronization with the pixel clock to simultaneously select the data bus line of the same LCD panel and select the multi-level data bus line to A data bus driver for applying a display voltage of a magnitude corresponding to the pixel data of the tonal representation, and the display voltage applied to the pixel electrode and the common electrode provided at the intersection of the scan bus line and the data bus line. A liquid crystal cell that displays the brightness corresponding to the pixel data of the multi-gradation expression by changing the transmittance according to the voltage difference from the applied common voltage; An active matrix liquid crystal display comprising: an applied voltage correction unit that changes the display voltage applied to the pixel electrode of the liquid crystal cell or the common voltage applied to the common electrode of the liquid crystal cell according to the number of the selected scan bus line. In the apparatus, the applied voltage correction means adjusts the holding means for holding the basic correction coefficient for each number or representative number of the scan bus line and the size of the adjusted correction coefficient generated based on the basic correction coefficient. And adjusting the display voltage applied to the pixel electrode of the liquid crystal cell or the common voltage applied to the common electrode of the liquid crystal cell by using the adjusted correction coefficient adjusted by the adjustment unit. It is characterized by doing.

[0009]

In the present invention, the basic correction coefficient can be made variable, and an appropriate basic correction coefficient corresponding to the relationship between the liquid crystal panel and the line of sight can be obtained.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 7 are views showing a first embodiment of an active matrix type liquid crystal display device according to the present invention. In FIG. 2, 10 is a liquid crystal panel (see reference numeral 3 in FIG. 11 for the detailed configuration), 11 is a digital display data D _IN which is rearranged for each scan line pixel by pixel, and corresponds to gradation information of each pixel data. One voltage is converted into a plurality of reference voltages V ₀
˜V _{N− 1} selected from the data bus drivers and applied to the data bus lines of the liquid crystal panel 10, the reference numeral 12 generates a plurality of reference voltages V _{0 to} V _N−1 , and applies each of the voltages. The data power supply circuit 13 for correction according to the correction voltage ΔV _D from the correction means 14 generates a constant voltage (common voltage V _C ) to be applied to the common electrode of the liquid crystal panel 10 and, if necessary, the common voltage V _{D. This} is a common power supply circuit for correcting _C according to the correction voltage (ΔV _D ) from the applied voltage correction means 14. Although a scan bus driver, a scan power supply circuit, and the like are provided in addition to these, they are omitted here because they are not directly related to the invention.

Here, the applied voltage correction means 14 comprises a counting means 15, a first adjusting section 16, a holding means 17, a correction voltage generating means 18 and a second adjusting section 19, and the counting means 1
Reference numeral 5 is a unit for counting the horizontal synchronizing signal Hs and outputting a signal # representing the number of the scan bus line, the first adjusting unit 16
Outputs one selection signal SEL by manual operation. The holding means 17 stores a plurality (for example, three) of characteristic data 17a to 17c of different types, and each characteristic data is given an address in the order of scan bus line numbers (or in the order of representative numbers). It is composed of a large number of unit data, and each of the unit data corresponds to the basic correction coefficient described in the gist of the invention. According to the holding means 17, one characteristic data is selected according to the signal SEL, and one unit data (basic correction coefficient) in the selected characteristic data is read according to the signal #. Reference numeral H _D represents the read basic correction coefficient.

The correction voltage generation means 18 converts the basic correction coefficient H _D read from the holding means 17 into an analog voltage, further adds an arbitrary offset amount to the analog voltage, and further converts the analog voltage into an arbitrary voltage. The correction voltage Δ that is amplified by the gain and corresponds to the adjusted correction count
V _D is generated. In addition, the second adjusting unit 19,
Any offset operation amount H _OFS by manual operation
And an arbitrary gain manipulated _variable H _GAIN .

Therefore, the holding means 17 corresponds to a holding means for holding the basic correction coefficient for each number or representative number of the scan bus line, and the first adjusting section 16 or the second adjusting section. Corresponds to an adjusting unit that adjusts the magnitude of the basic correction coefficient. In such a configuration, the respective characteristic data 17a to 17c stored in the holding means 17 are set based on the relationship between the liquid crystal panel and the line of sight. For example, in the case of a liquid crystal panel that appears to change from “dark” to “bright” from the top to the bottom of the panel when facing the liquid crystal panel,
Characteristic data having an array of basic correction coefficients capable of gradually changing the brightness from “bright” to “dark” in the order of the numbers of the canvas lines is set. When the characteristic data is selected by operating the first adjusting unit 16, each of the reference voltages V _{0 to} V _N-1 is corrected by the basic correction coefficient read from the holding unit 17 in the order of the scan bus line numbers. Therefore, only when the liquid crystal panel is directly faced, the liquid crystal panel 10
The brightness in the vertical direction appears to be uniform.

When looking down or looking up at the liquid crystal panel, the shape of the characteristic data (specifically, the offset and inclination) so that the luminance distribution in the vertical direction of the liquid crystal panel becomes uniform.
Change. For this _purpose , the second adjustment unit 19 may be operated to appropriately adjust the offset operation amount H _OFS and the gain operation amount H _GAIN . In addition, when the vertical luminance distribution of the liquid crystal panel is not uniform, for example, when the vertical luminance of the liquid crystal panel changes from “dark” to “bright” and then it is inverted to “dark” again, , The characteristic data suitable for it is stored in the holding means 17, and the characteristic data is stored in the first adjusting unit 16.
It may be selected by the operation of.

FIG. 3 is a concrete configuration diagram of the first embodiment. Reference numeral 20 is a counter as a counting unit, 21 is a DIP switch as a first adjusting unit, 22 is a memory as a holding unit, 23 is a voltage generating circuit as a correction voltage generating unit, and 24 is a data generating circuit as a second adjusting unit. And
The voltage generation circuit 23 includes a D / A converter 23a and an adder 23b.
And an amplifier 23c, and the data generating circuit 24 is manually operated to an arbitrary offset operation amount H _OFS.
And a second data generator 24b for generating an arbitrary gain manipulated _variable H _GAIN by a manual operation. The counter 20, the dip switch 21, the memory 22, the voltage generation circuit 23, and the data generation circuit 24 constitute an applied voltage correction means 25 as a unit.

The data power supply circuit 12 has a predetermined high voltage.
Voltage V_HAnd the output of the applied voltage correction means 25 (gradation correction voltage
ΔV_D) And a first adder 12a for adding
Pressure V _LSame gradation correction voltage ΔV_DSecond adder for adding and
12b and the outputs of these two adders 12a and 12b
The resistor network 12c that divides the voltage and the voltage of each node of the resistor network 12c.
A plurality of buffers 12d to 12g for extracting pressure,
V_H+ ΔV_DVoltage V_OAnd V_L+ ΔV_DPhase
Applicable voltage V₇And V₀And V₇of
Six voltages V divided between₁~ V₆To occur. V₀~
V₇Is ΔV_DChanges in proportion to, for example, ΔV_DLarger
Then the brightness decreases, and ΔV_DBrightness decreases
(However, normally white type LCD panel
In the case of Le).

Here, the memory 22 is, for example, a read-only memory having an address space of 512 bits, and the address space is divided into four blocks of 128 bits for use. Among the 9-bit addresses A _{0 to} A ₈ , the upper 2 bits (A ₇ , A ₈ ) select the block, and the remaining 7 bits (A _{0 to} A ₆ ) specify the address in the selected block. The read data is, for example, 8 bits (D _{0 to} D ₇ ) and has an arbitrary basic correction coefficient in the range from the value (minimum resolution) assigned to the least significant bit (D ₀ ) to a value corresponding to 256 times the value. Can be expressed.

FIG. 4A shows an example of characteristic data (hereinafter referred to as first characteristic data) stored in one block (block designated by A ₇ = 0 and A ₈ = 0) of the memory 22.
In the figure, the vertical axis corresponds to addresses A _{0 to} A ₆ (scan bus line numbers), and the horizontal axis corresponds to the magnitude of the basic correction coefficient. When the signal SEL is set to A ₇ = 0 and A ₈ = 0 by operating the dip switch 21, the first characteristic data is selected on the memory 22. When the addresses A _{0 to} A ₆ change in the order of the # of canvas lines, the basic correction coefficients are sequentially read out along the curve of the characteristic data of FIG. The correction amount to be read has a value with a smaller scan bus line number #, that is, a value that raises the brightness at the upper part of the screen (looking up), and a value with a larger scan bus line number #, that is, the lower part of the screen (viewing). It has a value to decrease the brightness in the direction of decreasing).

[0019] Thus, using such first characteristic data, a reference that along the data configuration can generate a tone correction voltage [Delta] V _D to vary the number of scan bus lines are retrieved from the data source circuit 12 Voltage V
It is possible to correct _{0 to} V ₇ . As a result, the brightness above the screen can be increased and the brightness below the screen can be decreased, and the brightness in the vertical direction of the liquid crystal panel can be made uniform and viewed.

By the way, the first characteristic data is data when facing the liquid crystal panel, and is not suitable when looking down or looking up at the entire liquid crystal panel. For example, when looking down, while suppressing the brightness of the entire screen,
It is necessary to further reduce the brightness at the bottom of the screen. For this _purpose , the data operation circuit 24 may appropriately adjust the offset operation amount H _OFS and the gain operation amount H _GAIN to transform the first characteristic data. FIG. 4B shows these two manipulated variables (H
It is a modification of the first characteristic data obtained when _OFS , H _GAIN ) is increased. The offset operation amount H _OFS moves the first characteristic data as a whole to the right, and the gain operation amount H _GAIN makes the inclination steep. By such modification of the first characteristic data, the brightness of the entire screen can be suppressed, the brightness below the screen can be further reduced, and a change in the installation angle of the liquid crystal panel can be dealt with.

The first characteristic data is the viewing angle characteristic in which the luminance distribution in the vertical direction changes substantially linearly, that is,
The present invention can be applied to a liquid crystal panel having a viewing angle characteristic that gradually changes from “dark” to “bright” from the upper side to the lower side of the screen. However, depending on the liquid crystal panel, there are those in which the viewing angle characteristics change non-linearly, for example, “dark” → “bright” → “dark”. Therefore, the above first characteristic data alone is preferable in terms of versatility. Absent. Therefore, the characteristic data set for the liquid crystal panel having such a non-linear viewing angle characteristic, for example, as shown in FIGS. 5A and 5B is stored in the memory 22 in advance, and the DIP switch 21 is operated. According to these three types of characteristic data, that is, the characteristic data of FIG. 4A (first characteristic data) and FIG.
Characteristic data (second characteristic data) or characteristic data (third characteristic data) of FIG. 5B is appropriately selected.

The second characteristic data is the dip switch 21.
Signal A to SEL₇= 1, A ₈Set to = 0
Is selected. This second characteristic data is
Has a viewing angle characteristic that the upper side and the lower side appear dark when
It is applied to a liquid crystal panel that has a vertical brightness.
It has a correction characteristic that can be raised. Also,
For the third characteristic data, the signal SEL is A₇= 0, A₈= 1
It is selected when set, looking down on the entire panel
When turned down, the brightness counter from "dark" to "bright" at the bottom of the screen
It is applied to a liquid crystal panel with a viewing angle characteristic that can be seen to roll.
It This third characteristic data is applied from the top to the bottom of the screen.
With a correction curve that gradually raises the brightness.
In addition, the local correction curve (symbol I
See).

Next, the operation will be described. The outputs Q _{0 to} Q ₇ of the counter 20 are counted up by +1 for each horizontal synchronizing signal Hs, but 7 bits (Q _{1 to} Q ₇ ) excluding the least significant bit (Q ₀ ) are scan bus line numbers #. Is taken out as a signal representing. That is, the number # is counted up every other horizontal synchronizing signal Hs, and the memory 2
Used for addressing 2. The reason why the least significant bit (Q ₀ ) is unused is to reduce the amount of data in the memory 22.

A plurality of characteristic data (for example,
The above-mentioned first to third characteristic data) are stored. this
These characteristic data are the contents (A₇, A₈) To
Therefore, the contents of the signal SEL selected are selected by the DIP switch.
It changes according to the setting of 21. For example, A₇= 0, A₈
If = 0, the first characteristic data is A₇= 1, A ₈
If = 0, the second characteristic data, or A₇= 0,
A₈If = 1, the third characteristic data is selected and the characteristic
Data content (gradation correction value) is 8 bits depending on the number #
(D₀~ D₇) Is read.

The tone correction value for each scan bus line number read from the memory 22 is stored in the D / A converter 23a.
After being converted into an analog voltage by the adder 23b, the adder 23b adds the offset manipulated variable H _OFS and the amplifier 23c amplifies it to a magnitude corresponding to the gain manipulated variable H _GAIN . These two manipulated variables H _OFS and H _GAIN can be freely changed in magnitude for each manipulated variable by, for example, a variable resistor provided in the data generation circuit 24.
By adjusting H _OFS , the overall brightness of the liquid crystal panel can be adjusted, and by adjusting H _GAIN , the degree of brightness difference in the vertical direction of the liquid crystal panel can be adjusted.

Here, the brightness correction does not consider the liquid crystal panel.
The dip switch 21 and operate the panel setting at that time.
Select the characteristic data that seems appropriate for the placement angle.
Uniform brightness distribution in the vertical direction of the LCD panel
Two manipulated variables H so that _OFS, H_GAINTo adjust the
It can be divided into two parts. The former step has multiple
From the characteristic data, it is suitable for the viewing angle characteristics of the liquid crystal panel.
This is to select only one characteristic data, this is the factory
Need only be done once at the shipping stage from
The installation angle of the panel changes, and the brightness in the vertical direction of the panel changes.
When the degree distribution is uneven, the latter step, namely
Two manipulated variables H_OFS, H_GAINYou can adjust.

Therefore, according to the above embodiment, the optimum characteristic data can be selectively used for various types of liquid crystal panels having different viewing angle characteristics, so that the versatility can be improved and the liquid crystal panel Since it is possible to perform appropriate brightness correction according to the installation angle, it is possible to provide a practical display quality improvement technique that is suitable for a liquid crystal display device having a large screen size.

In the above embodiment, the common gradation correction voltage ΔV _D is used for the data and the common. However, for example, as shown in FIG. 6, different correction voltages (ΔV _D , ΔV _D) are used.
_C ) may be generated. That is, the voltage generation circuit 23A includes a common D / A converter 23a, a data adder 23b, and an amplifier 23c, as well as a common adder 23d and an amplifier 24e.
Individual adders 23b and 23d and amplifiers 23c and 23e
_Includes an offset operation amount H _OFS1 and a gain operation amount H _GAIN1 for the data generated by the data generation circuit 24A, and an offset operation amount H _OFS2 and a gain operation amount H for the common.
_GAIN2 and are given respectively. The data generating circuit 24A includes common first and second data generating units 24c and 24d in addition to the data first data generating unit 24a and the second data generating unit 24b. Figure 7
FIG. 7 is a diagram showing the data power supply circuit 13 and the common power supply circuit 13A corresponding to FIG. 6, and the configuration of the common power supply circuit 13A is different. That is, the subtracter 1 for generating a common voltage applied to the common electrode by subtracting the gradation correction voltage [Delta] V _C for the common from the basic common voltage V _C (V _C -ΔV _C)
The difference is that 3Aa is provided.

8 to 10 are views showing a second embodiment of the active matrix type liquid crystal display device according to the present invention.
The same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In FIG.
Reference numeral 30 denotes an applied voltage correction means, and the applied voltage correction means 30
Are the counting means 15 and the first adjusting unit 1 similar to those in the first embodiment.
6, a correction voltage generating means 18 and a second adjusting section 19 are provided, and a multi-bit signal (a signal indicating the scan bus line number #) from the counting means 15 and a multi-bit signal from the first adjusting section 16 ( Signal SEL) to generate an address signal ADRS, and
And a holding unit 32 for storing predetermined basic characteristic data. Here, the basic characteristic data is a series of several characteristic data, and each characteristic data is the signal S.
It is adapted to be selected by the upper bits of the address signal ADRS corresponding to EL. That is, when the content of the signal SEL is changed by operating the first adjustment unit 16, one of the characteristic data items that form the basic characteristic data item is selected, and one correction value H _D in the selected characteristic data _item is selected. The address signal ADRS corresponding to the number # is read according to the lower bits.

FIG. 9 is a block diagram when the second embodiment is applied to a liquid crystal display device having an analog data driver. In FIG. 9, 33 is a counter as a counting unit, 34 is a DIP switch as a first adjusting unit, and 35
Is an adder circuit as an address generation circuit, 36 is a read-only memory (hereinafter referred to as memory) as a storage unit, 37 is a correction voltage generation unit, 38 is a second adjustment unit, 39 is a power supply circuit for data including an amplification circuit 39a, Reference numeral 40 is a common power supply circuit, 41 is a liquid crystal panel, and 42 is an analog data driver. The amplifier circuit 39a of the data power supply circuit 39 changes the impedance of the photocoupler PC inserted between the input and output of the operational amplifier OP by Δ, as described in FIG.
It may be controlled by V _D.

FIG. 10 is a diagram showing an example of basic characteristic data stored in the memory 36. This basic characteristic data is composed of three characteristic data and which are divided by addresses. The characteristic data of 1 has a downward-sloping characteristic corresponding to the first characteristic data of the first embodiment, and the characteristic data of 3 has a mountain-shaped characteristic corresponding to the second characteristic data of the first embodiment. The characteristic data has a downward sloping characteristic corresponding to the third characteristic data of the first embodiment.

Also in the above configuration, one of a plurality of characteristic data (-) can be selected by operating the DIP switch 34, and the selected characteristic data is used to correct data in the order of scan bus line numbers. it is possible to read the H _D. Then, as in the first embodiment, the offset operation amount H _OFS and the gain operation amount H _GAIN for the correction data H _D can be arbitrarily adjusted. Also,
In the second embodiment, since one type of basic characteristic data is used by dividing the address, if the division boundary portions are made to overlap, the amount of data can be reduced corresponding to the overlapping amount. it can.

[0033]

According to the present invention, since the correction gradation voltage is variable, it is possible to provide a practical viewing angle correction technique for a liquid crystal display device.

[Brief description of drawings]

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

FIG. 2 is a basic configuration diagram of the first embodiment.

FIG. 3 is a detailed configuration diagram of the first embodiment.

FIG. 4 is a conceptual diagram of an example of first characteristic data of the first embodiment and a modified conceptual diagram thereof.

FIG. 5 is a conceptual diagram of an example of second characteristic data and third characteristic data of the first embodiment.

FIG. 6 is a detailed configuration diagram of the main parts showing a modification of the first embodiment.

7 is a configuration diagram of a data power supply circuit and a common power supply circuit corresponding to FIG. 6;

FIG. 8 is a basic configuration diagram of a second embodiment.

FIG. 9 is a detailed configuration diagram of a second embodiment.

FIG. 10 is a conceptual diagram showing an example of basic characteristic data of the second embodiment.

FIG. 11 is an overall configuration diagram of a liquid crystal display device.

FIG. 12 is a graph showing the relationship between the brightness of one pixel of the liquid crystal panel and the viewing angle.

[Explanation of symbols]

C: common electrode Ck: transfer clock (pixel clock) DB _i : data bus line G _i : pixel electrode Hs: horizontal synchronizing signal (horizontal scanning signal) M _i : liquid crystal cell SB _i : scan bus line V _ON : gate-on voltage V _{0 to} V _N-1 : reference voltage (display voltage) V _C : common voltage 4: scan bus driver 5: data bus driver 10, 41: liquid crystal panel 14, 25, 30: applied voltage correcting means 16: first adjusting unit (Adjusting part) 17, 32: Holding means 19: Second adjusting part (adjusting part) 21: DIP switch (first adjusting part; adjusting part) 22, 36: Memory (holding part) 24, 24A, 38: Data generation Circuit (second adjusting unit; adjusting unit)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Nakabayashi 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (4)

[Claims] 1. A scan bus driver for sequentially selecting a scan bus line of a liquid crystal panel in synchronization with a horizontal scanning signal and applying a gate-on voltage to the selected scan bus line, and a multi-gradation expression synchronized with a pixel clock. A data bus driver for inputting pixel data, simultaneously selecting data bus lines of the same liquid crystal panel, and applying a display voltage of a magnitude corresponding to the pixel data of the multi-gradation expression to the selected data bus lines; and the scan bus line And a pixel of the multi-gradation expression, which is provided at the intersection of the data bus line and changes the transmittance according to the voltage difference between the display voltage applied to the pixel electrode and the common voltage applied to the common electrode. A liquid crystal cell displaying a brightness corresponding to data, and a display voltage applied to the pixel electrode of the liquid crystal cell or a common electrode of the liquid crystal cell. In the active matrix type liquid crystal display device, the applied voltage correction means changes the voltage of the scan bus line according to the number of the selected scan bus line. Holding means for holding the basic correction coefficient, and an adjusting section for adjusting the size of the adjusted correction coefficient generated based on the basic correction coefficient, the adjusted correction coefficient adjusted by the adjusting section. Is used to correct the display voltage applied to the pixel electrode of the liquid crystal cell or the common voltage applied to the common electrode of the liquid crystal cell. 2. The holding means holds a plurality of basic correction coefficients having different values for the same number of the scan bus line, and arbitrarily selects one of the basic correction coefficients. The active matrix liquid crystal display device according to claim 1, which is configured to obtain the liquid crystal display device. 3. The holding means continues a number of values of basic correction coefficients along a characteristic curve of an arbitrary shape, divides the characteristic curve into several, and sets a basic correction coefficient group for each division. The active matrix liquid crystal display device according to claim 1, which is selectively used. 4. The active matrix type liquid crystal display device according to claim 1, wherein the adjusting section adjusts an amplification factor and an offset amount of an amplifier for amplifying the basic correction coefficient.