JP4876437B2 - Driving method of display device - Google Patents

Description

  The present invention relates to a display driving method for driving a plurality of display elements with a common driver element.

  Conventionally, as a driving method of a display device having a plurality of display screens such as a main display screen and a sub display screen like a display device of a mobile phone, a dedicated driver element is installed in each display element, and these driver elements Thus, there are known a method of independently driving each display screen and a method of sharing driver elements of a plurality of display elements as shown in Patent Document 1 (hereinafter referred to as a parent-child drive method).

The latter parent-child drive method can reduce both the mounting area and the number of parts compared to the former independent drive method, and is advantageous for downsizing and cost reduction of the display device.
JP 2005-92218 A

  However, since the parent-child drive method uses a common driver element, multiple display screens connected to the common driver element are always driven even when only one display element is used, compared to the independent drive method. Therefore, there is a problem that the power consumption is considerably increased.

  An object of the present invention is to provide a driving method of a display device in which a plurality of display elements are driven by a common driver element with low power consumption.

The display device driving method of the present invention includes at least a main display screen and a sub-display screen, and drives the plurality of display screens by a common driver element, wherein m, n, p, q, and r are respectively set. When the natural number is used, the display device includes m scanning lines and n data lines, and the main display screen has
p> (m / 2)
P sub scanning lines and n data lines satisfying the sub display screen,
q = m−p
Q scanning lines satisfying
r <n
R data lines that satisfy
The driver element includes a main display mode in which m scanning lines of the display device are sequentially selected and scanned in a period of one frame, and the m scanning lines are divided into a plurality of scanning line groups. the scanning line groups has a plurality of the scanning lines of the same number of adjacent, said plurality of one made to correspond to the scanning lines with each other included in each of the scan line groups, during one frame, all characterized by having a sub-display mode a plurality of scanning lines selected simultaneously, scanning the respective scan lines of each of all the scanning line groups are sequentially selected and the said corresponding in the scanning line groups It is what.

According to the display device driving method of the present invention, a plurality of scan lines are divided into a plurality of scan line groups for each of a plurality of adjacent scan lines of the same number, and in the sub display mode in the main display mode. Since one scanning line included in each scanning line group is associated with each other in one frame period, and a plurality of corresponding scanning lines in all the scanning line groups are simultaneously selected and driven, individual scanning in the sub display mode is performed. A long line scanning period can be ensured. As a result, in the sub display mode, the driving frequency of one frame is reduced to reduce power consumption, and the occurrence of display defects due to insufficient writing is suppressed.

According to the display device driving method of the present invention, in the sub display mode, m scan lines are divided into two scan line groups having the same number of adjacent scan lines, and the correspondence between these two scan line groups is divided. The two scanning lines are simultaneously scanned during one frame period, and white or black monotone display data is supplied to the n data lines in a scanning period other than the period for scanning the scanning line corresponding to the sub display screen. Preferably, the data output load is reduced and the power consumption is further reduced.

  In the above-described sub display mode, the black monotone display data is supplied to the n data lines in a scanning period other than the period for scanning the scanning line corresponding to the sub display screen, thereby the main display screen. It is preferable to display a wide image in which the upper and lower edge areas corresponding to (p−q) / 2 scanning lines are displayed in black monotone, so that the upper and lower edge areas are displayed in black monotone on the main display screen. Can be displayed in a sub display mode with low power consumption.

  In the display device driving method of the present invention, in the main display mode, white or black monotone display data is supplied to the n data lines during a scan period corresponding to the sub display screen. This reduces the data output load in the main display mode and reduces power consumption, and the common data line group with the sub display screen on the main display screen and the dedicated data line group only on the main display screen It is possible to prevent the deterioration of image quality due to the occurrence of a vertical band which is a kind of luminance unevenness at the boundary portion of.

  FIGS. 1A and 1B are perspective views showing a mobile phone equipped with a display device as an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the configuration of scanning lines and data lines in the display device. It is.

  As shown in FIG. 1, the mobile phone according to the present embodiment is configured such that a display panel unit 1 and an operation panel unit 2 are rotatably connected to each other by a hinge 3. In the closed state in which both panel portions 1 and 2 shown in FIG. 1A are overlapped, that is, in the reception standby state in which the telephone is not used, only the sub display screen 1a is exposed, and FIG. The main display screen 1b is exposed in the open state in which the telephone set in which the displayed display panel unit 1 is rotated and separated from the operation panel unit 2 can be used.

  Therefore, the image of the main display screen 1b is not visually recognized by the telephone user in the closed state, and the user operates the operation key 2a of the operation panel unit 2 while visually checking the main display screen 1b in the opened state. Therefore, unless the telephone is reversed, the sub display screen 1a located on the back side of the main display screen 1b is not visually recognized by the user.

  The mobile phone display device of this embodiment is an active matrix type liquid crystal display device, and, as shown in FIG. 2, a sub-device comprising a display element that performs a matrix display composed of 96 scanning lines and 96 data lines. The display screen 1a, the main display screen 1b composed of display elements for performing matrix display composed of 320 scanning lines and 240 data lines, includes 240 source lines Ls1 to Ls240 and 416 gate lines Lg1 to Lg416. Active matrix driving is performed by one driving circuit having the same.

  Of the 240 source lines Ls1 to Ls240, 72 source lines Ls1 to Ls72 and source lines Ls169 to Ls240 on both sides are dedicated source lines for driving only the main display screen 1b. The 96 source lines Ls73 to Ls168 are shared source lines that drive both the sub display screen 1a and the main display screen 1b, and are connected in common to the corresponding TFTs (not shown) on both screens 1a and 1b.

  Accordingly, the sub display screen 1a is driven by 96 gate lines Lg1 to Lg96 and 96 source lines Ls73 to Ls168 orthogonal to them, and the main display screen 1b has 320 gate lines Lg97 to Lg416 and these. It is configured to be driven by 240 source lines Ls1 to Ls240 that are orthogonal to each other. That is, the sub display screen 1a is a 96 × 96 pixel thin film transistor (TFT) liquid crystal display screen, and the main display screen 1b is a 240 × 320 pixel TFT liquid crystal display screen.

  The 416 gate lines Lg1 to Lg416 and the 240 source lines Ls1 to Ls240 described above are conductively connected to corresponding output terminals (not shown) of the driver element 4 as indicated by two-dot chain lines.

  The mobile phone display device according to the present embodiment has two display drive modes, a sub display mode and a main display mode, as driving methods.

  In the sub display mode, as shown in FIG. 2, all 416 gate lines Lg1 to Lg416 are divided into 208 parts every two, and a first scanning line group composed of gate lines Lg1 to Lg208 and gate lines Lg209 to Lg416. Are driven as a total of two scanning line groups. Accordingly, one first scanning line group is composed of the sub display screen 1a (gate lines Lg1 to Lg96) and one edge of the main display screen 1b (arrangement area of the gate lines Lg97 to Lg208).

  FIG. 3 is a timing chart showing an operation of scanning the above-described 416 all gate lines Lg1 to Lg416 in the sub display mode. As is apparent from this timing chart, a gate pulse voltage is applied to the 208th gate line Lg208 sequentially from the gate line Lg1 in one frame, and at the same time, the same gate is applied to the 416th gate line Lg416 sequentially from the 209th gate line Lg209. A pulse voltage is applied.

  That is, the same gate pulse voltage is sequentially applied to the corresponding gate lines of each scanning line group, Lg1 and Lg209, Lg2 and Lg210, Lg3 and Lg211... Lg207 and Lg405, and Lg208 and Lg416. That is, the first scanning line group and the second scanning line group are scanned simultaneously.

  In this way, in the sub display mode, all the gate lines Lg1 to Lg416 are divided into two scanning line groups and driven simultaneously, so that the driving frequency of one frame is half of the total number of gate lines, that is, 208 of 416. Become. As a result, the power consumption is reduced and the scanning period for one gate line is doubled, so that the writing time for one pixel can be doubled for a long time. Occurrence of display defects due to insufficient writing is prevented.

  In this sub display mode, the same image as the sub display screen is displayed on the main display screen 1b in a limited area corresponding to the sub display mode. However, the sub display mode is closed in the cellular phone shown in FIG. Since the mode is executed in the completed state, the main display screen is not visually recognized by the user, and the image content is not a problem.

  On the other hand, in the main display mode, as shown in FIG. 4, normal line-sequential driving is performed in which 416 gate lines Lg1 to Lg416 are sequentially scanned during one frame period. In this case, when 96 gate lines Lg1 to Lg96 corresponding to the sub display screen 1a are scanned, a data signal voltage for displaying a white monotone image is applied to all 240 source lines Ls1 to Ls240. When 320 gate lines Lg97 to Lg420 corresponding to the main display screen 1b are scanned, the data signal voltage corresponding to the image signal input to the driver element 4 is displayed on all source lines in order to display a desired image. Applied to Ls1 to Ls240. Thereby, the entire surface of the sub display screen 1a is displayed in white, and an image corresponding to the input image signal is displayed on the main display screen 1b.

  Thus, in the main display mode, when the gate lines Lg1 to Lg96 corresponding to the sub display screen 1a are scanned, the white monotone data signal voltage is applied to all the source lines Ls1 to Ls240. Compared with the case where the data signal voltage is applied, the output load is reduced, and the power consumption is reduced accordingly. Furthermore, display quality deterioration due to a so-called “vertical band”, which is a display defect that easily occurs in the parent-child drive system as in this embodiment, is prevented.

  The “vertical band” is an area where the source lines Ls73 to Ls168 are shared for both the sub and main display screens, and the source lines Ls1 to Ls72 and the source lines Ls169 to Ls240 that are dedicated to the main display screens on both sides of the area. This is a luminance unevenness band generated at the boundary portion of the line, and is generated based on a difference in output load between the shared source line and the dedicated source line.

  In the main display mode of the present embodiment, the white display data signal voltage is uniformly applied to all the source lines Ls1 to Ls240 while scanning the gate lines Lg1 to Lg96 corresponding to the sub display screen 1a (hereinafter referred to as a subscanning period). Is applied, the output loads of the source lines Ls1 to Ls240 are made substantially uniform, and the deterioration of display quality due to the occurrence of the “vertical band” described above is prevented.

  The data signal voltage uniformly applied to the source lines Ls1 to Ls240 during the sub-scanning period is not limited to the white display data signal voltage, and may be a black display data signal voltage. In this case, the sub display screen 1a is white or black. The main display mode is executed when the mobile phone shown in FIG. 1B is opened, and the sub display screen 1a in this state is directly visible to the user. Therefore, even the white or black monotone display does not particularly reduce the product quality.

  FIG. 5 is an explanatory diagram showing a modification of the sub display mode in the present embodiment. In this modified sub display mode, the display of both the sub display screen 1a and the main display screen 1b is controlled by the sub display mode in which the first scanning line group and the second scanning line group are simultaneously scanned. In each period of scanning the first to 96 gate lines Lg1 to Lg96 and Lg209 to Lg304 in the scanning order in the line group, a desired image data signal voltage is applied to all the source lines Ls1 to Ls240, and the remaining 112 are both In each period during which the gate lines Lg97 to Lg208 and Lg305 to Lg416 are scanned, the black monotone display data signal voltage is applied to all the source lines Ls1 to Ls240.

  As a result, a horizontal wide image whose upper and lower edge areas are black is displayed on the main display screen 1b as shown in the figure. When the mobile phone is opened and the main display mode is being executed, the horizontal wide image is automatically displayed in the main display mode as a sub-display when the timer function is activated automatically when left unattended for a predetermined time. The mode is switched to the mode and displayed in the automatically switched sub display mode. By adopting such a configuration, when the user forgets to close the mobile phone after using it, the main display mode is continued for a long time to avoid wasting power. This reduces the power consumption of the mobile phone. In this horizontal wide image, if you display simple basic information such as date, time, remaining battery level and reception status, or a simple warning message such as "Let's close your phone!" Product value is improved.

  As described above, the driving method of the active matrix display device for a mobile phone according to the present embodiment includes both the sub display mode corresponding to the sub display screen and the main display mode corresponding to the main display screen, and the sub display mode. In the mode, since all the gate lines are divided into the same number of scan line groups and the two scan line groups are simultaneously scanned, the frame frequency is reduced by half and the power consumption is reduced. Since a long writing time for the pixels can be secured, the occurrence of display defects due to insufficient writing such as so-called tailing and black floating can be suppressed, and high display quality can be maintained.

  Further, in the main display mode, black or white display data is uniformly applied to all source lines during the scanning period of the sub display screen 1a to obtain a monotone display, thereby reducing the output load on all source lines. This contributes to a reduction in power consumption, and the output load for all source lines is made uniform, and at the boundary between the sub-main main screen shared source line compatible area and the main screen dedicated source line compatible area on both sides of the main display screen. It is possible to prevent the so-called “longitudinal band” that easily develops, and to maintain a high display quality.

In addition, this invention is not limited to said embodiment.
For example, in the above embodiment, the number of scanning line groups in the sub display mode is two scanning line groups. However, the number of scanning line groups is not limited to this, and may be three or more scanning line groups as shown in FIG. In the example of FIG. 6, there are 104 gate lines corresponding to the sub display screen 61, 364 gate lines corresponding to the main display screen 62, a total of 468 gate lines in 78 scan lines, and so on. It is divided. In this case, the black monotone display signal voltage is supplied to all the source lines Ls1 to Ls240 during the period of scanning the first 26 gate lines in each scanning line group of 78 gate lines. In addition to the 26 gate lines on the display screen 61, the lower edge areas 61a and 61b are displayed in black monotone, and the horizontal wide image similar to that shown in FIG. .

  In addition, the present invention is not limited to the active matrix type liquid crystal display device, but is applied to a simple matrix type liquid crystal display device and other display devices other than the liquid crystal display device, which are matrix driven by a plurality of scanning lines and a plurality of data lines. Of course, it can be widely applied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a mobile phone to which a display device according to an embodiment of the present invention is applied, in which (a) shows its closed state and (b) shows its open state. It is explanatory drawing which shows the scanning line group structure of the sub display mode in the said display apparatus for mobile phones. 6 is a timing chart showing a scanning driving operation in a sub display mode of the mobile phone display device. It is explanatory drawing which shows the drive state of the main display mode in the said display apparatus for mobile phones. It is explanatory drawing which shows the modification of the image displayed in the sub display mode of the said display apparatus for mobile telephones. It is explanatory drawing which shows the scanning line group structure in the sub display mode of the said mobile phone display apparatus, and the other modification of a display image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display panel part 1a, 61 Sub display screen 1b, 62 Main display screen 2 Operation panel part 3 Hinge 4 Driver element Lg Gate line Ls Scan line

Claims (4)

A display device driving method comprising at least a main display screen and a sub display screen, and driving the plurality of display screens by a common driver element,
When m, n, p, q, and r are natural numbers,
The display device includes m scanning lines and n data lines,
The main display screen is
p> (m / 2)
P scanning lines and n data lines satisfying
The sub display screen is
q = m−p
Q scanning lines satisfying
r <n
R data lines that satisfy
The driver element includes a main display mode in which m scanning lines of the display device are sequentially selected and scanned in a period of one frame, and the m scanning lines are divided into a plurality of scanning line groups. the scanning line groups has a plurality of the scanning lines of the same number of adjacent, said plurality of one made to correspond to the scanning lines with each other included in each of the scan line groups, during one frame, all characterized by having a sub-display mode a plurality of scanning lines selected simultaneously, scanning the respective scan lines of each of all the scanning line groups are sequentially selected and the said corresponding in the scanning line groups A display device driving method.   In the sub display mode, m scan lines are divided into two scan line groups having the same number of adjacent scan lines, and the corresponding two scan lines in these two scan line groups are divided. 2. The monotone display data of white or black is supplied to the n data lines during a scanning period other than a period during which the scanning lines corresponding to the sub display screen are scanned. A driving method of the display device.   In the sub display mode, by supplying black monotone display data to the n data lines during a scanning period other than the period for scanning the scanning line corresponding to the sub display screen, the main display screen is displayed. The display device driving method according to claim 2, wherein a wide screen is displayed in which the upper and lower edge areas corresponding to (p−q) / 2 scanning lines are displayed in black monotone.   The white or black monotone display data is supplied to the n data lines in a period during which the scan line corresponding to the sub display screen is scanned in the main display mode. Method for driving the display device.

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