EP0778557A2 - Appareil d'attaque pour cristal liquide et instruments personnels incorporant celui-ci - Google Patents

Appareil d'attaque pour cristal liquide et instruments personnels incorporant celui-ci Download PDF

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Publication number
EP0778557A2
EP0778557A2 EP96305812A EP96305812A EP0778557A2 EP 0778557 A2 EP0778557 A2 EP 0778557A2 EP 96305812 A EP96305812 A EP 96305812A EP 96305812 A EP96305812 A EP 96305812A EP 0778557 A2 EP0778557 A2 EP 0778557A2
Authority
EP
European Patent Office
Prior art keywords
liquid crystal
crystal driving
driving apparatus
latch circuit
characters
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP96305812A
Other languages
German (de)
English (en)
Other versions
EP0778557A3 (fr
Inventor
Shinichi c/o Seiko Instruments Inc. Nogawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Seiko Instruments Inc
Original Assignee
Seiko Instruments Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP7311119A external-priority patent/JPH08272340A/ja
Application filed by Seiko Instruments Inc filed Critical Seiko Instruments Inc
Publication of EP0778557A2 publication Critical patent/EP0778557A2/fr
Publication of EP0778557A3 publication Critical patent/EP0778557A3/fr
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers

Definitions

  • the present invention relates to a liquid crystal driving apparatus for use in a display means such as a portable or personal information terminal or the like, and particularly to a liquid crystal driving apparatus for reading out font data from a character font ROM to display characters on a matrix-type display device, and a portable or personal instrument using the same.
  • a liquid crystal driving apparatus having a character font ROM generally displays any character at a specific position on a liquid crystal display by writing any character code into a specific address of a display RAM (Random Access Memory).
  • a character code is read out from the display RAM in synchronism with a display timing to input the character code into a character font ROM (hereinafter referred to as "CGROM (Character Generator ROM)”) and then transmit character font data to a display device.
  • CGROM Character font ROM
  • the display operation of the liquid crystal driving apparatus is under the control of a CPU.
  • a CPU interface 9 serves as an input port for the CPU, and the CPU writes a display content into the display RAM 10 through the CPU interface 9, that is, the CPU writes the character code into the specific address corresponding to a specific position on a display panel.
  • a character code is periodically read out from the display RAM 10 by a timing control circuit 8, and then input to the CGROM 11.
  • the timing control circuit 8 generates a common timing and transmits common timing information to a common driver 13.
  • the timing control circuit 8 also transmits the common timing information to the CGROM 11, and the CGROM 11 determines data of character fonts to be output on the basis of both the signals of the character code from the display RAM 10 and the common timing information.
  • the character font data from the CGROM 11 are transmitted to a shift latch circuit 12.
  • the shift latch circuit 12 continues a data shift operation until display data of one line in a horizontal direction of the display panel are filled, and transmits the shift result as display data to a segment driver 14.
  • Fig. 3 shows an example of the shift latch circuit 12.
  • the character font data are output from the CGROM 11 every character. Therefore, when four characters are required to be displayed as shown in Fig. 4, the CGROM 11 is accessed at four or more times at one common timing (for data of one line in the horizontal direction).
  • the font data are loaded to a shift register group A of Fig. 3, and then the font data are shifted to a shift register group B with a shift clock signal which is output from a shift CLK generator 15.
  • a scroll operation of displayed characters on a dot basis in a horizontal direction like an electric sign board, has been conventionally performed by changing the number of shift clock pulses generated in a CLK generator 15 shown in Fig. 3.
  • a display character can be shifted to the left side dot by dot every time the clock number is incremented by "1" as shown in Fig. 4.
  • a character display mode when display pixels are arranged in a matrix form, a blank dot line is disposed between characters to represent the boundary between the characters as shown in Fig. 4.
  • a character font display mode For example, when plural characters each of which is represented with 5x7 dots are displayed in a horizontal direction, it is reasonable to represent the characters with character fonts each of which comprises 6x7 dots containing a line of blank dots.
  • the mode in which each character is represented with a character font of 6x7 dots is referred to as "6-dot font display mode" in this specification.
  • Both the 6-dot font display mode and the 5-dot font display mode can perform a scroll operation in the horizontal direction by using a conventional driving apparatus, like an electric sign board.
  • the second problem is as follows.
  • the scroll operation is carried out, like the electric sign board, in the 5-dot font display mode by using a display panel having no wiring for pixels at the boundary between characters, the blank between the characters is lost through one-dot scroll as shown in Fig. 8B (i.e., the neighbouring characters are brought into contact with each other at the edge portions thereof), and further each character itself is laterally extended at portions of the panel where the wiring is omitted. Therefore, the character is deformed at these portions, and this causes erroneous character recognition.
  • a liquid crystal driving apparatus comprising a storage device for storing character font data and outputting font data every character, a shift latch circuit for developing the output of the storage device into image data of one line in a horizontal direction on a display panel, and a segment driver for converting the output of the shift latch circuit to a liquid crystal driving waveform, characterised in that said shift latch circuit comprises a first latch circuit for holding the output of said storage device at a first timing (LCLO), a first shifter circuit for receiving the output of said storage device and the output of said first latch circuit at the first timing and shifting the received outputs by a predetermined bit amount, second latch circuits whose number is equal to the number of characters in the horizontal direction and which are connected to one another in parallel so as to successively hold the output of said first shifter circuit at serial timings (LCL1-LCL4), and a third latch circuit for holding the output of the second latch circuit at a second timing (LCL5).
  • LCLO first timing
  • a first shifter circuit for receiving the output of said storage device and
  • a liquid crystal driving apparatus having a storage device for storing character font data and outputting font data every character, a shift latch circuit for developing the output of the storage device into image data of one line in a horizontal direction on a display panel, and a segment driver for converting the output of the shift latch circuit to a liquid crystal driving waveform, characterised by further comprising a second shifter circuit which is provided to prevent bits corresponding to blank data between characters out of image data of one line in the horizontal direction on a display panel, which are developed by said shift latch circuit being supplied to the segment driver.
  • font data (corresponding to a character) which are read out from the storage device such as the CGROM which serves to store character font data and output the font data every character, are first held at the first timing by the first latch circuit.
  • Both the output (font data) of the first latch circuit and font data (corresponding to a character adjacent to the above character) which are sequentially read out from the CGROM are arranged, and then these font data of the neighbouring two characters are shifted in the first shifter circuit, and the output of the first shifter circuit is held into the second latch circuits at sequential timings. Therefore, the number of shift clock pulses is not necessary to be proportional to the total dot number, but may be proportional to the number of characters in the horizontal direction. Accordingly, the frequency of the shift clocks can be reduced, and thus the first. problem can be solved.
  • the circuit connection is made so that in the 5-dot font display mode, the blank data to be displayed at the wiring-omitted portions between characters are avoided by the second shifter circuit, so that a scroll operation can be performed without deforming the characters.
  • Fig. 8C shows a display example of this case. When the characters are scrolled to the left side by one dot, the left edges of the characters are just. hidden at the blank space portions as shown in Fig. 8C, and the hidden edge of each of the characters appears at its neighbouring character area again when the characters are scrolled by a further one dot, i.e. a total of two dots.
  • Such a display is just like an outside scene which is viewed through a window of a travelling train. That is, a part of the scene which is hidden by the frames of the window cannot be seen, however, it can be seen as the train travels. Likewise, by continuously scrolling the displayed characters, the characters can be seen with no deformation as if they flow in the horizontal direction, whereby the erroneous character recognition can be suppressed.
  • Fig. 1 shows a shift and a latch circuit according to the present invention.
  • the output of the first shifter circuit 1 is latched and held at sequential timings (LCL1 to LCL4) every time the character font data are read out from the CGROM 11.
  • a timing control circuit 8 shown in Fig. 2 counts a display timing so as to meet the number of characters to be displayed in the horizontal direction (in this case, four characters). It is apparent from a timing chart of Fig. 6A that the display timing is counted from “0" to "4". In synchronism with this timing, character codes are transmitted from the display RAM 10 to the CGROM 11, and then the CGROM 11 outputs character font data ("A", "B", “C”, “D”, “E") as shown in Fig. 6A.
  • the output of the CGROM 11 is taken into a first latch circuit 3 at a first timing (i.e, LCLO) which is output every time the count value of the display timing varies, and both the output (LTOUT) of the first latch circuit 3 and the output of the CGROM 11 are input to a first shifter circuit 1.
  • a first timing i.e, LCLO
  • the output (LTOUT) of the first latch circuit 3 and the output of the CGROM 11 which correspond to neighbouring display characters are arranged in the horizontal direction, and shifted to the left aide by a specified scroll amount.
  • (b2, bl, b0) (0, 2, 0), that is, two-dot shift is performed, and 4 dots at the right side of the character font "A” and 2 dots at the left side of the character font "B" are output from the first shifter circuit 1.
  • the output of the first shifter circuit 1 is held in the second latch circuits 4, 5, 6 and 7 at the sequential timings LCL1, LCL2, LCL3 and LCL4 which are successively output every time the count of the display timing varies.
  • the data are held in the third latch circuit 2 at a second timing of LCL5, and transmitted to a segment driver 14.
  • the filling of the image data of one line in the horizontal direction on the display panel is performed by using the sequential clocks (LCL1 to LCL4) which are generated every display timing as shown in Fig. 6. That is, it is sufficient to generate the latch clock on a character basis every time the character font data output from the CGROM 11 vary
  • latch clock pulses for only five characters are sufficient even when the character font data of five characters are loaded from the ROM.
  • character codes must be beforehand read out from the display RAM 10. Therefore, the liquid crystal driving apparatus needs clocks operating at one-rank higher speed to access to the display RAM 10. However, if there are clocks whose speed is twice as high as the latch clocks for five characters, the continuous access to the RAM and the ROM can be performed.
  • the outputs of the second latch circuits 4 to 7, that is, pixel data (S1, S2, S3, ..., S34, S35, S36) to be displayed in the horizontal direction are input to the second shifter circuit 20, and the output of the second shifter circuit 20 is input to the third latch circuit 2.
  • a second shifter circuit 20 able to accept the output from six second latch circuits i.e. display data for six characters
  • the pixel data in the horizontal direction contain blank data at the boundaries between characters in the 6-dot font display mode.
  • the blank data are input to S1, S7, S13, S19, S25, S31, and these data are not required in the 5-dot font display mode.
  • the second shifter circuit 20 is connected to remove these unnecessary data in the 5-dot font display mode.
  • the pixels S2 to S6 are connected (input) to the inputs D1 to D5 of the third latch circuit 2, the pixels S8 to S12 are connected to D6 to D10, and the pixels S14 to S18 are connected to D1 to D15. That is, the second shifter circuit 20 is constructed so that the pixels S1, S7, S13, S19, S25, S31, corresponding to the blank data in the pixels S1 to S36 are not input to the third latch circuit 2.
  • the multiplexer 19 shown in Fig. 7 can switch the 6-dot font display mode and the 5-dot font display mode to. each other by selecting one of the data in two directions.
  • the multiplexer 19 outputs an input from an upper right side to a lower side, as shown in Fig. 7.
  • This data flow corresponds to a shift operation. Therefore, in Fig. 7, the blank data of S1, S7, S13, S19, S25, S31 are neglected, and the third latch circuit 2 holds the pixel data at the second timing and outputs SEG data to the lower side.
  • the multiplexer 19 outputs an input from an upper left side to a lower side, as shown in Fig. 7. This data flow corresponds to a non-shift operation.
  • the font data at the left edges of the characters of the respective pixel data enter the positions S1, S7, S13, 519, S25, S31.
  • the data at these positions are neglected, and thus these data are not displayed.
  • the font data of the left edge of each character is displayed at the right edge in a display area of a character which is adjacent to the character at the left side. That is, the display shown in Fig. 8C is performed.
  • the characters are scrolled without being deformed in the 5-dot font display mode. Accordingly, the output of the second shifter circuit is input (connected) to the third latch circuit 2 in this embodiment, however, the same effect can be performed by using another connection (inputting) method.
  • the same effect can be obtained by the following method: all the pixel data (S1, S2, S3, ..., S34, S35, S36) to be displayed in the horizontal direction are held at the second timing in the third latch circuit 2, and the output of the third latch circuit 2 is input to the second shifter circuit 20 to delete the blank data at the positions S1, S7, S13, S19, S25, S31 and output the residual data to the segment driver 14. That is, the second shifter 20 may be disposed at any stage before the pixel data (S1, S2, S3, ..., S34, S35, S36) to be displayed in the horizontal direction are input to the segment driver 14.
  • the present invention has two methods, a first method of solving the first problem, and a second method of solving the second problem. These two methods show their effects individually and independently. That is, the frequency of the clocks required for the display can be reduced by using the first method for the first problem. Further, the scroll operation on dot basis can be performed with no deformation by using the second method for the second problem.
  • the lateral. scroll operation can be performed with no character deformation by using the 5-dot font display node having high display efficiency, and in addition, the frequency of the clocks for display can be lowered to reduce a current demand, thereby achieving a performance which is required for a portable or personal instruments having batteries.
  • liquid crystal driving apparatus of this invention When the liquid crystal driving apparatus of this invention is combined with a display panel on which display pixels are arranged in a matrix form, a liquid crystal display device having the above effects can be achieved.
  • a liquid crystal display device having the above effects can be achieved.
  • the apparatus when the apparatus is combined with a CPU and a battery, a portable or personal instrument having excellent portability and the above effects can be achieved.
  • the clocks requited for the liquid crystal driving apparatus can be achieved at a sufficiently lower frequency than the conventional liquid crystal driving apparatus.
  • liquid crystal display device as described above is formed of a one-chip integrated circuit, the current demand of the integrated circuit can be reduced, and the improvement in lifetime of batteries, etc. which is required for future portable instruments can be achieved.
  • the scroll operation on dot basis like an electric sign board can be performed with no character deformation as shown in Fig. 8C.
  • the characters are scrolled in the horizontal direction without being deformed, a user can be prevented from erroneously recognising the characters.
  • This invention provides a liquid crystal driving apparatus having a storage device for storing character font data and outputting font data every character, a shift latch circuit for developing the output of the storage device into image data of one line in a horizontal direction on a display panel, and a segment driver for converting the output of the shift latch circuit to a liquid crystal driving waveform, characterised by further comprising a second shifter circuit which is provided to avoid bits corresponding to blank data between characters out of image data of one line in the horizontal direction on a display panel, which are developed by said shift latch circuit.
  • This invention provides a liquid crystal driving apparatus which contains a character font ROM therein and can perform a scroll display operation of displayed characters on dot basis in a horizontal direction, characterised in that character font data of two characters which are continuously read out from said character font ROM are shifted by a number of dots by a parallel shifter, and a shift result is latched every character to be displayed.
EP96305812A 1995-11-29 1996-08-07 Appareil d'attaque pour cristal liquide et instruments personnels incorporant celui-ci Withdrawn EP0778557A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP311119/95 1995-11-29
JP7311119A JPH08272340A (ja) 1995-02-01 1995-11-29 液晶駆動装置およびそれを用いた携帯機器

Publications (2)

Publication Number Publication Date
EP0778557A2 true EP0778557A2 (fr) 1997-06-11
EP0778557A3 EP0778557A3 (fr) 1997-12-03

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EP96305812A Withdrawn EP0778557A3 (fr) 1995-11-29 1996-08-07 Appareil d'attaque pour cristal liquide et instruments personnels incorporant celui-ci

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EP (1) EP0778557A3 (fr)
KR (1) KR100402227B1 (fr)
NO (1) NO963320L (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112513971A (zh) * 2018-07-26 2021-03-16 武藏工业株式会社 文字列显示设备及文字列显示方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3149897A1 (de) * 1980-12-16 1982-07-29 Casio Computer Co., Ltd., Tokyo Elektronische einrichtung
US4358761A (en) * 1979-09-28 1982-11-09 Sanyo Electric Co. Ltd. Dot matrix display apparatus
US4538145A (en) * 1981-10-15 1985-08-27 Tokyo Shibaura Denki Kabushiki Kaisha Data transfer control device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4358761A (en) * 1979-09-28 1982-11-09 Sanyo Electric Co. Ltd. Dot matrix display apparatus
DE3149897A1 (de) * 1980-12-16 1982-07-29 Casio Computer Co., Ltd., Tokyo Elektronische einrichtung
US4538145A (en) * 1981-10-15 1985-08-27 Tokyo Shibaura Denki Kabushiki Kaisha Data transfer control device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112513971A (zh) * 2018-07-26 2021-03-16 武藏工业株式会社 文字列显示设备及文字列显示方法
CN112513971B (zh) * 2018-07-26 2024-04-16 武藏工业株式会社 文字列显示设备及文字列显示方法

Also Published As

Publication number Publication date
NO963320D0 (no) 1996-08-08
KR100402227B1 (ko) 2004-03-30
KR970029303A (ko) 1997-06-26
EP0778557A3 (fr) 1997-12-03
NO963320L (no) 1997-05-30

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