JPH06202072A - Integrated circuit device for driving display panel - Google Patents

Abstract

PURPOSE:To prevent light and dark stripes from being generated on a screen owing to an error of a photoprocess when the integrated circuit device for data line driving of a display panel is manufactured. CONSTITUTION:When driving circuits 30 each including a couple of unit circuits 30a and 30b which hold video data Dv to be set corresponding to data lines of the display panel 10 alternately with time are arranged in the chip surface of the integrated circuit device 20 and integrated, the unit circuits 30a and 30b are arranged symmetrically with each other in the respective driving circuits 30 and the unit circuits 30a and 30b are also arranged symmetrically between the driving circuits 30 for adjacent data lines to distribute light '0' and dark 'X', appearing in a display of pixels owing to the error of the photoprocess, in the screen of the display panel 10, thereby preventing longitudinal stripes and lateral stripes from being generated on the display.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used to drive a data line when displaying video data on a liquid crystal type display panel, and is particularly suitable for displaying analog video data composed of MOS transistors. A suitable integrated circuit device.

[0002]

2. Description of the Related Art As is well known, a display panel for a variable image is of a so-called matrix type in which a large number of pixels are two-dimensionally arranged in a plane thereof, and an intersection of both lines is formed through a data line and a scanning line. The pixels corresponding to the above are driven for display, but in the display panel, a plurality of pixels arranged along a certain scanning line are usually displayed simultaneously or simultaneously, and accordingly, a pair of unit circuits is provided in the driving circuit for each data line. It is customary to provide both unit circuits to alternately hold video data over time. Hereinafter, an example of the display procedure and each data line driving circuit will be briefly described with reference to FIGS.

FIG. 2 schematically shows a drive circuit 20 for the display panel 10 and its data lines 11 and a drive circuit 40 for the scanning lines 12. The illustrated display panel 10 is of an active matrix type, and a display electrode 13 and a thin film transistor 14 which are enlarged and shown in the drawing are provided for each pixel corresponding to each intersection of a large number of data lines 11 and scanning lines 12. The driving of a large number of data lines 11 and scanning lines 12 is shared by a plurality of integrated circuit devices 20 and 40, respectively, and the shared range is shown by a pair of diagonal lines in the figure. The plurality of integrated circuit devices 40 for the scanning lines 12 start operating in response to the frame signal Sf, and sequentially switch the selection signals to be placed on the scanning lines 12 in synchronization with the scanning pulse SP, along each scanning line 12. Thin film transistor with multiple pixels lined up
Turn on 14 simultaneously. Each integrated circuit device 20 for driving the data line 11 clocks the video data Dv in the sharing range as a clock pulse.
After being sequentially read in synchronization with CP, a driving voltage corresponding thereto is output to the data lines 11 in the sharing range all at once, and the state is held during one cycle in which the scanning lines 12 are switched.

Therefore, each data line in the integrated circuit device 20 is
The driving circuit 30 of FIG. 3 for 11 is provided with a pair of unit circuits 30a and 30b which alternately hold the video data Dv. In the illustrated example, since the video data Dv is analog, the unit circuit 30a and
Reference numeral 30b includes an analog switch 31, an analog value holding capacitor 32, and an operational amplifier 33 connected to a voltage follower. The analog switches 31 of the unit circuits 30a and 30b are alternately turned on by a switching signal Sc whose logical state alternates every switching cycle of the data line 12, and correspondingly the outputs of the operational amplifiers 33 are similarly switched by the switching signal Sc. It is led to the output terminal To through the operated changeover switch 34 and placed on the data line 11.

FIG. 4 shows a conventional example of an integrated circuit device 20 incorporating a plurality of drive circuits 30. The simplified control circuit 21 includes a shift register that receives the clock pulse CP, and sequentially supplies the video data Dv corresponding to each drive circuit 30 via the wiring 22 in synchronization with the clock pulse CP. In each case, the unit circuits 30a and 30b described above are indicated by reference characters a and b in the frame of each drive circuit 30 that receives the above-mentioned switching signal Sc, and one of them is designated by the switching signal Sc among these a and b. While the driving voltage is being output from the output terminal To, the other side reads and holds the video data Dv. A plurality of such integrated circuit devices 20 are usually used as shown in FIG.
Each of the ten scanning lines 12 is selected so that a large number of pixels lined up along it are simultaneously displayed.

[0006]

In the above-described integrated circuit device for driving the data lines of the display panel, a stripe-shaped abnormal display occurs in the panel surface due to an error in the photo process during manufacturing. In particular, there is a problem that troubles are likely to occur particularly when the degree of integration of the integrated circuit device is further increased or when analog video data is displayed on the display panel. Hereinafter, the cause of this problem and the pattern of the abnormal display will be described with reference to FIG.

For high integration of the integrated circuit device, it is preferable to use a MOS transistor as its circuit element. However, even if the display panel is of a liquid crystal type, a driving voltage of 15 V or more is required, which is suitable for a small transistor. It is preferable that the source / drain layers have a double diffusion structure in order to have a withstand voltage. FIG. 5A shows a cross section of such a MOS transistor T with n
The channel type is shown below. As is customary, a gate oxide film 3 is attached to a region surrounded by an element isolation film 2 in a p-type semiconductor region 1, a gate 4 is disposed on the gate oxide film 3, and a source / drain layer having a double diffusion structure is provided on both sides of the gate oxide film 3. For diffusion, a low impurity concentration layer 5 and a high impurity concentration layer 6 are diffused in an n-type, the gate 4 is covered with an insulating film 7, and then an electrode film 8 is provided to provide terminals for a source S, a drain D and a gate G. Derive. This MOS transistor T
Since a slight error always accompanies the photo process when forming a pattern with a very small pattern in the integrated circuit device, the positions of the low impurity concentration layer 5 and the high impurity concentration layer 6 with respect to the gate 4 are very slight, but easily misaligned. Therefore, the capacitances C _L and C _R between the gate 4 and the left and right low impurity concentration layers 5 and the resistances R _L and R _R of the left and right low impurity concentration layers 5 when turned on are slightly different from each other. become.

FIG. 5 (b) schematically shows a state in which the unit circuits 30a and 30b of FIG. 3 are built in the integrated circuit device 20, represented by transistors Ta and Tb and Cs corresponding to the capacitor 32, respectively. In the example of the figure, the drive circuit 30 of FIG.
A pair of transistors Ta and Tb corresponding to is distributed in the upper half and the lower half of the chip of the integrated circuit device 20 and arranged side by side in two stages.
The order of arranging Tb and Tb is opposite to each other corresponding to FIG. Further, in each pair, the transistors Ta and Tb are arranged with the drain side to which the capacitor Cs is connected aligned in the same direction. In FIG. 5B, this drain side of the transistor Ta in each pair is the output terminal To. The state of being connected with is shown.

In the chip of the integrated circuit device 20 as shown in FIG. 5B, the left and right electrostatic capacitances C _L and C in each transistor Ta and Tb are caused by the error of the photo process described in FIG. 5A.
_{When R} and the resistors R _L and R _R become uneven, an error occurs in the holding voltage of the capacitor Cs, and thus the drive voltage output from the terminal To. Now, assuming that this drive voltage is shifted in the direction of brightening the display on the upper side of the chip of the integrated circuit device 20 of FIG. 5 (b), the source / drain positions of the transistors Ta and Tb are on the upper side and the lower side of the chip. Since it is in the opposite direction, the lower side of the chip will be shifted in the direction of darkening the display.

The manner in which an error occurs in the display of the pixel is shown in FIGS. 5 (c) and 5 (d), respectively.
The case where the drive voltage is output from the side is schematically shown. In each of these, 2 in the chip of the integrated circuit device 20
Within the frame of the drive circuits 30 arranged in rows, O is attached when the display is shifted in the direction of brightening, and X is attached when the display is shifted in the direction of darkening. In the example of FIG. 5 (b), since the sources and drains of the transistors Ta and Tb in each drive circuit 30 are arranged in the same direction, the distributions of O and X in FIGS. 5 (c) and 5 (d) are the same.
Since the source and drain of transistors Ta and Tb are arranged in opposite directions on the upper side and the lower side in the chip, the distributions of O and X are opposite.

FIG. 5 (e) shows the light and dark distributions of the display on the display panel 10 corresponding to FIGS. 5 (c) and 5 (d) by O and X. The right side of the figure shows the case where a is driven by the transistor Ta as shown in FIG. 5 (c), and the b is the case where it is driven by the transistor Tb as shown in FIG. 5 (d). (d)
The upper side and the lower side of FIG. 5 correspond to the left half and the right half of FIG. 5 (e), respectively. As can be seen from FIG. 5 (e), when the integrated circuit device 20 is manufactured, a photo process error causes a bright O and a dark X stripe on the display panel 10. In this example, wide vertical stripes are generated and the difference in brightness is large. It becomes very unsightly.

As the integration degree of the integrated circuit device is increased, such a problem that the stripes appear on the display is more likely to occur due to a slight error in the photo process, and the difference in brightness between the stripes becomes particularly large when analog video data is displayed. Cheap.
It should be noted that the problem that stripes are generated to the same extent not only when the integrated circuit device 20 is configured by MOS transistors as described above but also when it is configured by other transistors, and digital video data is displayed. Even if you do, the difference in brightness is not large, but the occurrence of stripes is often detected,
Human vision is quite sensitive to such anomalous displays.

In order to solve such a problem, for example, FIG.
When the source / drain arrangement direction of the transistor Tb in each pair of the transistors Ta and Tb in (b) is reversed from that of the transistor Ta, bright O and dark X in FIG. However, thin and bright horizontal stripes appear on the screen of Fig. 5 (e). Furthermore, the drive circuit 30 of FIG.
Even when the arrangement and arrangement direction of the plurality of transistors forming the unit circuits 30a and 30b are changed variously, the results are almost the same, and it is very difficult to prevent vertical stripes and horizontal stripes from appearing on the display screen. Have difficulty.

An object of the present invention is to solve the above problems and to configure an integrated circuit device for driving a data line so as to prevent a striped abnormal display on the screen of a display panel.

[0015]

According to the display panel driving integrated circuit device of the present invention, a pair of unit circuits for alternately holding the video data to be placed on the data lines of the display panel over time. When arranging and integrating the drive circuits including the above in a chip, one and the other unit circuits of each drive circuit are arranged in a pattern symmetrical to each other in the arrangement direction,
This is also achieved by arranging one and the other unit circuit corresponding to each other between the drive circuits for the data lines which are close to each other in a pattern symmetrical to each other in the arrangement direction.

It is best to use the drive circuits for the data lines adjacent to each other, as well as the drive circuits for the data lines adjacent to each other. In addition, in the present invention, each unit circuit is
This is advantageous when applied to the case where the OS transistor, especially the source / drain layer is composed of a MOS transistor having a double diffusion structure, and the case where the video data to be held by each unit circuit is analog.

[0017]

According to the present invention, the photo-process error that causes the problem occurs in the same direction with respect to the circuit elements integrated in the chip, and a pair of unit circuits of each driving circuit alternately alternates with time. Focusing on the fact that the retained video data is spatially displayed alternately on the display panel,
By arranging a pair of unit circuits symmetrically with each other in each drive circuit or between adjacent drive circuits as described in the configuration of the preceding paragraph, the light and dark appearing in the pixel display due to the error of the photo process can be applied in both vertical and horizontal directions. The stripes are dispersed so that stripes on the display do not occur in the vertical and horizontal directions.

[0018]

Embodiments of the present invention will be described with reference to FIG.
Also in the embodiments described below, the procedure for driving the data line 11 of the display panel 10 by the integrated circuit device 20 is shown in FIG. 2, and the circuit configuration of each drive circuit 30 including the pair of unit circuits 30a and 30b is shown in FIG. As shown, the parts corresponding to those in FIG. 2 and subsequent figures are given the same reference numerals. In this embodiment, analog video data is displayed on the display panel 10 and MOS transistors are used for the circuit elements of the integrated circuit device 20, but the present invention is not limited to this and is also applicable to other cases. Is possible.

FIG. 1A shows an integrated circuit device for driving a data line.
A circuit configuration example of 20 is shown in the same manner as in FIG. In this embodiment as well, the control circuit 21 is provided for the drive circuits 30 arranged in the upper and lower two stages.
Clock pulse CP from the video data Dv via wiring 22
Are sequentially given in synchronism with the pair of unit circuits in each drive circuit 30.
While one of 30a and 30b reads the video data Dv while the other holds it and outputs the drive voltage corresponding to the value from the output terminal To, it is the same as the conventional one, but in the present invention, the unit circuit 30a is used. The arrangement of the pattern of the transistors composing 30b and 30b is different from the conventional one. FIG. 1B shows an example of the arrangement according to the present invention for two adjacent drive circuits 30. In the same manner as in FIG. 5B, the unit circuits 30a and 30b are represented by one transistor Ta and Tb, respectively. It shows typically.

As shown in the figure, the sources S and drains D of the transistors Ta and Tb in each drive circuit 30 are arranged in the opposite directions, and the sources of the transistors Ta and Tb of the same kind are arranged even between adjacent drive circuits 30. The S and drain D arrays are arranged in opposite directions. In the present invention, the unit circuits 30a and 30b are arranged in a symmetrical pattern in each drive circuit 30 as described above, and two adjacent drive circuits 30 of the same type are used in this embodiment. Unit circuit 30a and
30b are arranged in a pattern symmetrical to each other. In FIG. 1A, this symmetrical arrangement is schematically shown by the reverse order of a and b in the frame of the adjacent drive circuit 30. Also in the present invention, when an error in the photo process occurs during the manufacture of the integrated circuit device 20, light and dark appear in the display of the pixel, but the error in the photo process occurs in the same direction for all the circuit elements, so that it is easily understood. As described above, when the pixel display by one of the two unit circuits symmetrically arranged as described above is bright, the display by the other always becomes dark.

1 (c) and 1 (d) show the state in which driving voltages are output from the unit circuits 30a and 30b of the driving circuit 30 of the integrated circuit device 20, respectively, in the same manner as in FIGS. 5 (c) and 5 (d). In the figure, the distribution of bright O and dark X of pixel display due to the error of the photo process is shown. Since the unit circuits 30a and 30b in each drive circuit 30 are symmetrically arranged, the bright O and the dark X in FIGS. 1 (c) and 1 (d) are reversed,
Since the corresponding unit circuits 30a and 30b of the adjoining drive circuits 30 are symmetrically arranged, in both FIGS. 1 (c) and 1 (d), the horizontal direction in the drawing shows the drive circuit 30 in the arrangement direction in the chip. O and dark X alternate.

FIG. 1E shows the display state on the screen of the display panel 10 by the light and dark distribution of the pixels corresponding to FIGS. 1C and 1D. The upper and lower sides of the chip of the integrated circuit device 20 of FIGS. 1 (c) and 1 (d) correspond to the left and right halves of FIG. 1 (e), respectively, and the even number of driving circuits 30 are provided on the upper and lower sides of the chip, respectively. Are arranged. On the right side of the figure, a and b are shown to indicate the drive by the unit circuit 30a or the unit circuit 30b.
Is attached. Comparing this with FIG. 5 (e) of the prior art, the distributions of bright O and dark X are dispersed.
It can be seen that horizontal stripes can be prevented as well as vertical stripes as in (e).

The unit circuits 30a and 30b as in the present invention
If all of them are arranged in the same direction instead of being arranged symmetrically, all the pixels are aligned in bright O or dark X on the display of FIG. 1 (e), so that stripes can be prevented as far as it is, but the display panel 10 As shown in FIG. 2, a plurality of integrated circuit devices 20 are used for the driving, so that wide vertical stripes are likely to occur due to the light and dark generated on each chip. In order to prevent the occurrence of stripes, it is most advantageous to disperse the distribution of bright O and dark X for each chip as in the present invention.

[0024]

As described above, according to the present invention, an error in the photo process occurs in the same direction with respect to the circuit elements integrated in the chip, and a pair of unit circuits of each drive circuit alternate with time. Paying attention to the fact that the video data retained in the display is spatially alternately displayed on the panel surface, when the drive circuits are arranged and integrated in the chip of the integrated circuit device for driving the data line of the display panel, the unit By symmetrically arranging the circuit pattern in each drive circuit and between adjacent drive circuits, the light and dark appearing in the pixel display due to the error of the photo process are finely dispersed in both the vertical and horizontal directions of the display screen to form the bright and dark stripes. Occurrence can be completely prevented.

The present invention can be easily implemented without changing the chip size of the integrated circuit device by changing the pattern of the photomask for the photo process and without changing the manufacturing process thereof. Further, the present invention can be applied to the integrated circuit device for driving a display panel for displaying analog video data when the MOS transistor is highly integrated, so that the above effects can be exerted particularly advantageously, and the image quality of the display panel can be further improved. It is expected to contribute to the improvement of the economical efficiency of the integrated circuit device due to the high integration of the.

[Brief description of drawings]

1 shows an embodiment of an integrated circuit device for driving a display panel according to the present invention, FIG. 1 (a) is a circuit configuration diagram thereof, and FIG. 1 (b) is an arrangement of unit circuit pairs of two adjacent drive circuits. Schematic of example,
The same figure (c) is a plan view of an integrated circuit device chip showing the brightness of pixel display by one unit circuit, and the same figure (d) is a plan view of the chip of an integrated circuit device showing the brightness of pixel display by the other unit circuit. FIG. 7E is a partially enlarged plan view of the display panel showing the distribution of brightness of pixel display.

FIG. 2 is a circuit diagram of a display panel and a drive circuit showing a procedure for driving a data line by an integrated circuit device.

FIG. 3 is a circuit diagram showing a configuration example of a data line driving circuit of a display panel.

FIG. 4 is a circuit configuration diagram showing a conventional integrated circuit device for driving a display panel.

FIG. 5 relates to a conventional integrated circuit device for driving a display panel,
FIG. 1A is a cross-sectional view of a MOS transistor as a circuit element constituting the same, and FIG. 1B is a layout diagram schematically showing the arrangement of unit circuits in an integrated circuit device chip as represented by MOS transistors. The same figure (c) is a plan view of an integrated circuit device chip showing the brightness of pixel display by one unit circuit, and the same figure (d) is a plan view of the chip of an integrated circuit device showing the brightness of pixel display by the other unit circuit. FIG. 7E is a partially enlarged plan view of the display panel showing the distribution of brightness of pixel display.

[Explanation of symbols]

 10 Display panel 11 Display panel data line 20 Display panel driving integrated circuit device 30 Data line driving circuit 30a One unit circuit 30b Other unit circuit Cs Capacitor holding video data value D MOS transistor drain Dv video data O Bright display of pixel S Source of MOS transistor Ta MOS transistor representing one unit circuit Tb MOS transistor representing the other unit circuit

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[Procedure amendment]

[Submission date] July 19, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (3)

[Claims] 1. A plurality of drive circuits, each of which is provided corresponding to each data line of a display panel and includes a pair of unit circuits for alternately retaining video data to be placed on the display line, are integrated in a chip plane. One and the other unit circuit of each drive circuit are arranged in a pattern symmetrical to each other in the arrangement direction in the chip plane, and the drive circuits for the data lines adjacent to each other also correspond to each other. An integrated circuit device for driving a display panel, wherein unit circuits are arranged in a pattern symmetrical to each other in an arrangement direction on a chip surface. 2. The device according to claim 1, wherein each unit circuit includes a source / drain layer having a double diffusion structure.
A display panel driving integrated circuit device comprising a transistor. 3. The display panel driving integrated circuit device according to claim 1, wherein the video data to be held by each unit circuit is analog data.