JP2007508595A - Lookup table with gray level transition waveform for bistable display - Google Patents

Abstract

Methods and systems for controlling electrophoretic and other bistable displays (310). Coded data (605, 610, 615) for different pixel transitions and different temperatures for driving the display is stored in memory (320). The coded data has voltage levels and timing information for different pixel transitions. A portion of the encoded data (705, 710, 715, 720, 725, 730) is retrieved by a controller (100) such as an ASIC based on the selected pixel transition, temperature and update mode. A portion of the coded data including the fixed length frame instruction is decoded to provide the decoded data. The decoded data provides a voltage waveform that drives the display.

Description

  The present invention relates generally to electronic readers such as electronic books and electronic newspapers, and more particularly to a method and apparatus for controlling a bistable display such as an electrophoretic display.

  With recent technological innovations, “user-friendly” electronic reading devices such as e-books, which expand many possibilities, have appeared. For example, many things can be expected in an electrophoretic display. Such displays have inherent memory behavior and can hold images for a relatively long time without consuming power. Power is consumed only when the display is refreshed or updated with new information. Therefore, such a display consumes extremely low power, and such a display is suitable for application to portable electronic readers such as e-books and e-newspapers. Electrophoresis means the movement of charged particles in an applied electric field. When electrophoresis occurs in a liquid, the particle will become at a predetermined rate due to the viscous drag created by the particle, the charge of the particle (permanent or induced), the dielectric properties of the liquid, and the magnitude of the applied electric field. Moving. An electrophoretic display is a type of bistable display that does not consume power after an image is updated and that substantially maintains the image.

  For example, International Publication No. 99/53373, published on 9 April 1999, by Eink Inc., Cambridge, Massachusetts, USA, entitled Full Color Reflective Display with Multicolor Subpixels, has such a display. The device is shown. WO 99/53373 shows an electronic ink display having two substrates. One substrate is transparent and the other substrate is provided with electrodes arranged in a matrix. The position of the display element or pixel corresponds to the intersection of the row electrode and the column electrode. The display element is coupled to the column electrode using a thin film transistor (TFT), and the gate of the transistor is coupled to the row electrode. This mutual arrangement of display elements, TFT transistors, and row and column electrodes forms an active matrix. Furthermore, the display element has a pixel electrode. The row driver selects one row of the display element, and the column driver or source driver supplies a data signal to the selected row of the display element via the column electrode and the TFT transistor. The data signal corresponds to displayed graphic data such as text or a chart.

  The electronic ink is provided between the common electrode on the transparent substrate and the pixel electrode. The electronic ink has a plurality of microcapsules having a diameter of about 10 to 50 μm. In one method, each microcapsule has positively charged white particles and negatively charged black particles that are dispersed in a liquid carrier medium or fluid. When a positive voltage is applied to the pixel electrode, the white particles move to the transparent substrate side of the microcapsule, and the viewer recognizes the white display element. Similarly, the black particles move to the side of the pixel electrode opposite to the microcapsules, and these particles are not visible to the viewer. When a negative voltage is applied to the pixel electrode, the black particles move to the common electrode side of the microcapsule and face the transparent substrate, so that the display element appears dark to the viewer. Similarly, the white particles move to the side of the pixel electrode opposite the microcapsule, and these particles are not visible to the viewer. When the voltage is removed, the display device is maintained in an appropriate state, and thus a bistable characteristic is exhibited. In another method, the particles are provided in a colored liquid. For example, black particles are placed in a white liquid, or white particles are placed in a black liquid. Alternatively, other color particles may be placed in different color liquids, for example, white particles are placed in a green liquid.

  Other fluids such as air may be used as the medium to move the charged black and white particles in the electric field (eg, Bridgestone, SID 2003—Symposium on Information Display, March 18-23, 2003, Digest 20.3). Colored particles may be used.

To form an electronic display, electronic ink may be printed on a plastic film sheet on which circuit layers are laminated. The circuit forms a pixel pattern and is then controlled by a display driver. Since the microcapsules are dispersed in the liquid carrier medium, the existing screen printing process can be used to print the microcapsules on virtually any surface including glass, plastic, fabric and paper. . In addition, by using a flexible sheet, an electronic reading device approximating the appearance of a conventional book can be designed.
WO99 / 53373 pamphlet

  However, electrophoretic and other bistable displays require addressing and control in a different manner than other displays such as LCDs. Sensitivity to both drive voltage intensity / pulse width and voltage sign or polarity of these displays, relatively long switching or update times when updating black and white mode, longer update times when updating grayscale mode, and images This is because of the sensitivity to history.

  The present invention seeks to alleviate the foregoing and other problems by providing an effective method of controlling a bistable display.

  In a particular aspect of the present invention, a method of driving a display in a bistable device includes storing encoded data for different pixel transitions for driving the display, and at least a selection of the different pixel transitions. Retrieving a portion of the stored encoded data based on the received one, decoding the portion of the stored encoded data to provide decoded data, and the decoding Providing at least one voltage waveform for driving the display based on the digitized data.

  In addition, associated controllers and program storage devices are provided.

  Corresponding parts are designated by the same reference numerals in all figures.

  1 and 2 show an embodiment of a part of the display panel 1 of the electronic reading device. The electronic reading device includes a first substrate 8, a second substrate 9 facing the first substrate 8, and a plurality of image elements 2. The image element 2 is arranged in a two-dimensional structure substantially along a straight line. In the figure, the image elements 2 are shown as being separated from each other for clarity, but in practice, the image elements 2 are very close to each other and form a continuous image. . Only a part of the full display screen is shown in the figure. Other embodiments of the image element are possible, for example a honeycomb structure arrangement. An electrophoretic medium 5 having charged particles 6 is installed between the substrates 8 and 9. The first electrode 3 and the second electrode 4 correspond to each image element 2. A potential difference can be applied to the electrodes 3 and 4. In FIG. 2, the first substrate of each image element 2 has a first electrode 3, and the second substrate 9 has a second electrode 4. The charged particles 6 can occupy a position close to one of the electrodes 3 and 4 or an intermediate position between the two electrodes. Each image element 2 has an appearance determined by the position of the charged particles 6 between the electrodes 3 and 4. The electrophoretic medium 5 itself is shown, for example, in US Pat. Nos. 5,961,804, 6,120,839, and 6,130,774, and is available, for example, from Eink.

  For example, the electrophoresis medium 5 includes negatively charged black particles 6 in a white fluid. For example, when the charged particles 6 are present in the vicinity of the first electrode 3 due to a potential difference of +15 V, the appearance of the image element 2 becomes white. For example, when the charged particles 6 are present in the vicinity of the second electrode 4 due to a potential difference having an opposite polarity of −15 V, the appearance of the image element 2 becomes black. When charged particles 6 are present between the electrodes 3 and 4, the image element exhibits an intermediate appearance such as a gray level between black and white. An application specific integrated circuit (ASIC) 100 controls the potential difference of each image element 2 and forms a desired image, such as an image and / or text, on a full display screen. A full display screen is composed of a large number of image elements corresponding to the pixels in the display.

  FIG. 3 schematically shows an overview of the electronic reading device. The electronic reading device 300 has a display ASIC 100. For example, the ASIC 100 is a Philips “Apollo” ASIC e-ink display controller. The display ASIC 100 controls one or more display screens 310 such as an electrophoretic screen via the address circuit 305 to form a desired display text or image. The address circuit 305 has a driving integrated circuit (IC). For example, the display ASIC 100 applies voltage waveforms to individual pixels in the display screen 310 via the address circuit 305. The address circuit 305 provides information for addressing specific pixels, such as rows and columns, and a desired image or text is displayed. As will be described in more detail below, the display ASIC 100 allows a series of pages starting from different rows and / or columns to be displayed. The image or text data is stored in a memory 320 corresponding to one or more storage devices. One example is the Philips Electronics Small Factor Optical (SFFO) disk system, and other systems can use non-volatile flash memory. The electronic reader 300 further includes a reader controller 330 or a host controller that responds to user-operated software or hardware buttons 322, such as an instruction to the next page or an instruction to the previous page, etc. User instructions are implemented.

  The reader controller 330 may be part of a computer and may operate any type of computer code device, such as software, firmware, microcode or the like, and is thereby shown here. Such a function is obtained. Accordingly, a computer program product having such a computer code device is provided in a manner apparent to those skilled in the art. The controller 330 of the reading device further comprises a memory (not shown), which is a program storage device that accurately executes the instruction program, or that implements the method that provides the functions shown here. It is a computer. Such a program storage device can be provided by methods apparent to those skilled in the art.

  The display ASIC 100 may include logic for periodically performing a forced reset on the display area of the electronic book, for example, every x page display or every y minutes. Forced reset is performed every 10 minutes after activation and / or when the luminance deviation is greater than a value such as 3% reflection. In the case of automatic resetting, the allowable frequency is determined empirically based on the lowest frequency at which an acceptable image quality can be obtained. The reset may also be performed manually by the user using a function button or other interface device. For example, the reset is performed when the user starts reading with an electronic reading device or when the image quality deteriorates to an unacceptable level.

  As will be described in detail below, the ASIC 100 issues a command to the display address circuit 305 to drive the display 310 based on the storage information in the memory 320.

  The present invention may be applied to any kind of electronic reading device. FIG. 4 shows one possible example of an electronic reading device 400 having two separate display screens. Specifically, a first display area 442 is installed on the first screen 440, and a second display area 452 is installed on the second screen 450. The screens 440 and 450 are connected by a binding 445, which allows the screens to be folded flat on each other and spread flat on the surface. This arrangement is preferable in that it can be approximated to an operation for reading a conventional book.

  Various user interfaces are provided, and the user can issue commands such as turning the page forward and back. For example, the first region 442 has an on-screen button 424 that can be operated using a mouse or other pointing device, touch-sensitive operation, a PDA pen, or other conventional technology, and the electronic reader page You can move between. In addition to the page advance and page return instructions, a scroll up or down function within the same page may be provided. Alternatively, or in addition, a hardware button 422 may be provided that allows the user to perform page forward and page backward commands. The second region 452 may also include an on-screen button 414 and / or a hardware button 412. It should be noted that the frames 405 around the first and second display areas 442 and 452 are unnecessary when the display area is frameless. Similarly, other interfaces such as a voice command interface may be used. It should be noted that the buttons 412, 414; 422, 424 are not necessarily required for both display areas. That is, a single page forward and page return button set may be provided. Alternatively, both page feed and page return commands may be indicated by other devices such as a single button or rocker switch. Function buttons or other interface devices can also be provided to allow the user to manually reset.

  As another possible configuration, the electronic book may have a single display screen with a single display area that displays one page at a time. Alternatively, a single display screen may be divided into two or more display areas arranged horizontally or vertically, for example. Further, when a plurality of display areas are used, a series of pages can be displayed in a desired order. For example, in FIG. 4, the first page is displayed in the display area 442, and the second page is displayed in the display area 452. When the user requests to view the next page, the second page is displayed in the second display area 452 while the third page is displayed in the first display area 442 instead of the first page. Can be displayed. Similarly, the fourth page is displayed in the second display area 452, and so on. Alternatively, when the user requests to view the next page, both display areas are updated so that the first display area 442 displays the third page instead of the first page. In the second display area 452, a fourth page may be displayed instead of the second page. If a single display area is used, when the user enters an instruction to go to the next page, the first page is displayed, and then the second page is overwritten with the first page, which Repeated. This process can be reversed because of a page return instruction. This process can also be applied to languages such as Hebrew where text characters are read from right to left, and languages such as Chinese where text characters are read in column order instead of row order. .

Furthermore, it should be noted that it is not always necessary to display the entire page in the display area. A portion of the page is displayed and when the user looks at other portions of the page, the scroll function scrolls up, down, or scrolls left or right. A scaling function may be provided, in which case the user can change the size of the text or image. This is preferable, for example, for users with low vision.
(Description of control method)
As mentioned above, electrophoretic and other bistable displays need to be addressed and controlled differently than other displays such as LCDs. Sensitivity to both drive voltage intensity / pulse width and voltage sign of these displays, relatively long switching or update time when updating black and white mode, longer update time when updating grayscale mode, and sensitivity to image history For. For example, in the case of grayscale image transition, the shortest image update time is 900 ms. In addition, this display is bistable / image stable and has a high sensitivity to the image history, so that there is a high risk of image residue. Furthermore, the display is sensitive to temperature, and in order to drive the display at different temperatures, it is necessary to create and store a lookup table. The present invention provides an easy-to-use data format that is high speed, high efficiency and low cost.

  FIG. 5 shows an algorithm for controlling a display having a plurality of image update modes. Multiple display modes are used to increase the image update rate, which is beneficial to the user, for example to reduce the image update time. These modes include, for example, a black and white update (MU) mode 500, a gray scale update (GU) mode 510, an initialization (INT) mode 520, and a gray scale clear (GC) mode 530. The sleep state 540 is a state of the controller when waiting for a display update command. The interrelationship between these four modes is explained. For example, if a mode update is requested by a logic operation (display command generated by the host) in the reader control 330, the elapsed time from the last display refresh (clear sequence) is determined from the set value in the decision block 560. A determination is made as to whether it is too small. If so, at decision block 570, a determination is made whether the pixel transition flag “Q” is zero. (If all change pixels have a transition from black and white state to black and white state, flag Q is set to zero.) If this is positive, MU mode 500 is selected. If decision block 570 is false, GU mode 510 is selected. If decision block 560 is false, the refresh time is cleared at block 550 and GC mode 530 is selected.

  The MU mode 500 is loaded by the display ASIC 100 only when the black and white data is updated. This often occurs in black and white books, or subwindows. The GU mode 510 is used when at least some grayscale data is updated in the display. The total image update time in MU mode 500 is usually about half of the update time in GU mode. The INIT mode 520 is necessary when the use of the display 310 is started and / or periodically thereafter, for example, every 10 minutes. This display sequence is used only when the system power supply (battery) is removed and the contents of the ASIC memory are lost. In this situation, the display content is unknown, the system is initialized, the display is cleared to white, and the current image is recorded as white in the ASIC memory. GC mode 530 is optionally used when the same level of grayscale is not updated and the display needs to be reset after a specified time.

  In each mode of the display ASIC 100, each pixel receives one of 32 possible waveforms, depending on the data. The 16 waveforms correspond to even pixel transitions, and the 16 waveforms correspond to odd pixel transitions. In four possible modes, there are 128 possible waveforms used to drive each pixel. If necessary, if the waveform is not limited to even and odd pixel transitions, each pixel can receive one of 16 possible waveforms, and there are 64 possible waveforms used to drive each pixel. Exists. This number is even higher when considering each temperature. The present invention provides an effective controller for adjusting these variables and controlling displays such as electrophoretic displays or other bistable displays by providing an encoding method / format. As described in FIG. 3, according to the present invention, a dedicated controller such as ASIC 100 is provided, and a command is sent to the display address circuit 305 that drives the display 310 based on the stored information in the memory 320.

  FIG. 6 shows the data structure of the memory. In each display mode, when driving the pixels of the display, data used by the ASIC 100 is retrieved from the memory 320 using an appropriate waveform. According to one aspect of the invention, one or more frames of waveform data are provided from the memory 320 to the display ASIC 100 and the display 310 is driven. In particular, the waveform data may be installed in LUTs at different positions in the memory space 600 of the memory 320. This arrangement may be viewed as a lookup table (LUT), but the data structure is different from a conventional LUT used in, for example, an LCD. A separate block of data for each possible pixel transition is provided. For example, if a pixel is one of four grayscale levels: black (B), dark gray (DG), light gray (LG) and white (W), there are 16 possible pixel transitions. For example, B to B, DG, LG or W; DG to B, DG, LG or W; LG to B, DG, LG or W; and W to B, DG, LG or W. The number of transitions is the square of the number of grayscale levels.

  For example, if there are 16 possible transitions, memory space 600 has additional LUTs up to zero LUT 605, first LUT 610, and fifteenth LUT 615. Zero LUT 605 is designed as a default. The memory space 600 has an address of stored LUT data. For example, the address of the zero LUT 605 is stored in the memory space 635, the address of the first LUT 610 is stored in the memory space 640, and so on up to the fifteenth LUT stored in the memory space 645. Memory space 650 stores the controller and manufacturing data for ASIC 100. The LUT selection register 670 is used to select one LUT according to the pixel transition. The memory 320 is, for example, a nonvolatile flash memory.

  When the display is updated, 32 waveforms are formed in many frames at different timings. The display ASIC 100 needs to apply these waveforms to all the display pixels according to the pixel transition. Thus, the waveform is applied based on pixel parity. Pixel parity minimizes unwanted light effects by processing the pixels in the odd column display in a different manner than the pixels in the even column display. When a display update is requested, the display ASIC 100 reads the temperature and selects an appropriate display sequence from the LUT according to the temperature and the LUT selection register value (collection of frame instructions). Before each frame scan is initiated, the display ASIC 100 reads a “frame command” from, for example, an external non-volatile memory in the memory 320 that provides the LUT space. In one embodiment, each frame instruction is 11 bytes long. The command area provides the display ASIC 100 with all necessary information regarding the current frame, including the applied voltage of each pixel according to the transition and frame timing. In addition, logic is executed to store the previous state of each pixel. Based on this configuration, the ASIC 100 is designed to decode and execute this information, resulting in a series of many frames, and the desired waveform is applied to each pixel.

  In the waveform coding format that addresses this electrophoretic display, the coded waveform data is stored in memory 320 and decoded by ASIC 100. The waveform data format is a new definition and can be used for all electrophoretic displays, including displays that use 3 voltage source drivers (eg, -15V, 0V, + 15V) regardless of display size. it can. The decoded data is then used by the ASIC 100 to drive the display 310.

  In one possible embodiment for each pixel of the electrophoretic display, 32 different waveforms can be selected. This realization means that waveforms can be fetched from memory 320 in real time during display updates. Since it is preferable to use a slow (low cost) memory in order to reduce the manufacturing cost, data cannot be read from the memory 320 instantaneously when a pixel is displayed. The coded waveform needs to be associated with every pixel in the frame, and each pixel is read before displaying the frame. Since the waveform depends on the display temperature, there exists a link structure that satisfies this dependency.

  The ASIC 100 uses a minimum of 64 kilobytes of flash memory to store temperature LUTs, display sequence data, controller settings, and manufacturing data. Temperature LUTs up to 16 are stored in flash memory space between hexadecimal addresses 0 and DFDF, for example.

  Register 0x13 (670) associated with ASIC 100 is used to select one of the 16 LUTs. After reset, this register is set to default 0, and the default temperature LUT is selected from flash address 0.

In one possible method, each temperature LUT has a temperature range of 256, for example, every 1 ° C. for each temperature, and has a hypothetical value between −128 ° C. and + 127 ° C. as shown below. . All points are represented using two flash bytes in the order MSB, LSB. The position of the default temperature LUT is fixed. This starts at address 0 and ends at address 1FF (hexadecimal). Also, the flash memory location from address DFE0 (hexadecimal) to address DFFF (hexadecimal) is fixed, and these represent 16 address points for the 16 possible LUTs in the flash memory. The location between E000 and FFFF is stored for controller settings and manufacturing data.
(Temperature LUT)
The following LUT addresses correspond to, for example, offsets from the base LUT address represented by the LUT pointer. As an example, a relative address such as an offset is shown below.

（温度シーケンス／方法）
ディスプレイは、更新モードに応じた異なる波形を用いて更新する必要がある。この更新モードは、白黒更新（MU）、グレースケール更新（GU）、初期化（INT）、リフレッシュ等である。

(Temperature sequence / method)
The display needs to be updated using different waveforms depending on the update mode. This update mode includes black and white update (MU), gray scale update (GU), initialization (INT), refresh, and the like.

  Each pointer from the temperature LUT represents the 16 possible display sequences (modes), ie the absolute address for a block of 16 pointers. As shown in FIG. 7, specific sequences 705, 710, 715, 720, 725 and 730 are selected based on the display update mode 750. The order of the pointers for these sequences is fixed. An example is shown below.

表示シーケンスに対する各ポインタは、そのシーケンスに関するデータの絶対アドレスを表す。特定の設計では、データフォーマットは、全ての表示シーケンスにおいて等しく、11バイト長の1または2以上の記録を含む。4以上のドライバ電圧が使用される場合、記録長（フレーム構成）を増加させることができる。最後の記録の後、以下に例示するような表示シーケンスの最後が、例えば2バイトFFによって示される：
バイト0、バイト1、バイト2、バイト3、バイト4、バイト5、バイト6、バイト7、バイト8、バイト9、バイト10
バイト0、バイト1、バイト2、バイト3、バイト4、バイト5、バイト6、バイト7、バイト8、バイト9、バイト10
…
FFFF
シーケンス領域において1バイトFFのみが見出された場合、ASIC制御器100は、「ハードウェア振動」を実行する。ハードウェア振動は、より一般的には、例えば「ハードウェア駆動」として知られる駆動パルスである。ハードウェア駆動が用いられた場合、ディスプレイは、例えば、選択ドライバのような2以上のドライバICを並列に作動させることによって、または単一のドライバICから複数の同時出力を提供することによって、ディスプレイの2以上の配線に、同時にデータが送信されるモードで作動するように定められる。ディスプレイのゲートドライバのカスケード信号によって、ゲートドライバが並列に接続され、フレーム時間が最小限に抑制される。ディスプレイのソースドライバは、以下に示すように、FFバイト以降に表されるデータを取得する：
FF 振動＿データ＿バイト FF 振動データ＿バイト FF 振動＿データ＿バイト FFFF。

Each pointer to a display sequence represents the absolute address of the data for that sequence. In a particular design, the data format is the same for all display sequences and includes one or more records that are 11 bytes long. When a driver voltage of 4 or more is used, the recording length (frame configuration) can be increased. After the last recording, the end of the display sequence as illustrated below is indicated by, for example, 2 bytes FF:
Byte 0, Byte 1, Byte 2, Byte 3, Byte 4, Byte 5, Byte 6, Byte 7, Byte 8, Byte 9, Byte 10
Byte 0, Byte 1, Byte 2, Byte 3, Byte 4, Byte 5, Byte 6, Byte 7, Byte 8, Byte 9, Byte 10
...
FFFF
If only 1 byte FF is found in the sequence area, the ASIC controller 100 executes “hardware vibration”. Hardware vibration is more generally a drive pulse, for example known as “hardware drive”. When hardware drive is used, the display can be displayed by, for example, operating two or more driver ICs, such as select drivers, in parallel or by providing multiple simultaneous outputs from a single driver IC. These two or more wires are set to operate in a mode in which data is transmitted simultaneously. The gate drivers are connected in parallel by the display gate driver cascade signal, and the frame time is minimized. The display source driver obtains the data represented after the FF byte, as shown below:
FF Vibration_Data_Byte FF Vibration Data_Byte FF Vibration_Data_Byte FFFF.

  As shown below, bytes 0 to 7 represent 32 areas of 2 bits. Each region indicates a voltage (for example, 00 = 0V, 01 = + 15V, 10 = −15V) applied to the display pixel, and this voltage matches an index condition describing each sequence in the document. If more than 4 voltage levels are required in this example, the region will be longer than 2 bits. Byte 8 represents the display line time, byte 9 represents the delay between two consecutive display frames, and byte 10 represents the number of frames used in the sequence.

各シーケンスは、可能な画素遷移を示す同じインデックスを有する。バイト0からバイト7までの32の可能な電圧は、各シーケンスのインデックスと、以下のように対応する：

奇数のパリティおよび偶数のパリティの場合の表示シーケンスに使用されるマトリクス遷移の実際の例は、以下に示されている。

Each sequence has the same index indicating possible pixel transitions. The 32 possible voltages from byte 0 to byte 7 correspond to the index of each sequence as follows:

Actual examples of matrix transitions used in the display sequence for odd and even parity are shown below.

Odd parity

これらは、4つの可能な初期グレーレベル（黒色、濃灰色、薄灰色、白色）の一つから4つの可能な最終グレーレベルの一つに、画素の外観を変えるために使用される。
（制御器設定および製造データ）
図6のメモリ空間650は、以下のように分配されても良い。 Even parity

These are used to change the appearance of the pixel from one of the four possible initial gray levels (black, dark gray, light gray, white) to one of the four possible final gray levels.
(Controller settings and manufacturing data)
The memory space 650 of FIG. 6 may be distributed as follows.

リセットの後、パルス幅変調（PWM）値および境界外観は、2つの制御器レジスタ内のフラッシュメモリに複製され、ホストによって、以下のレジスタを記録することにより、変化させることができる：
−PWMレジスタ0ｘ11
−外観データレジスタ0ｘ12
（境界データ）
ディスプレイの周囲に境界が設けられる場合、表示境界は、他の表示画素として処理され、全ての表示画素と同時に更新される。デフォルトの表示境界値は、フラッシュメモリのアドレスE201（16進数）に保管される。例えば、表示境界値は、0、1、2、3（黒、灰色1、灰色2、白）としても良く、アドレスE201でのバイトの低ニブルによって表される。リセットの後、フラッシュメモリからデフォルトの境界値が読み出され、内部レジスタ、境界データレジスタ（12進数のアドレスレジスタ）の低ニブルに記録される。このレジスタの高ニブルは、リセット後に0に設定される。境界データレジスタの低ニブルは、新たな境界値を表し、高ニブルは、実際の境界値を表す。

After reset, the pulse width modulation (PWM) value and boundary appearance are replicated to the flash memory in the two controller registers and can be changed by the host by recording the following registers:
-PWM register 0x11
-Appearance data register 0x12
(Boundary data)
When a boundary is provided around the display, the display boundary is processed as another display pixel and is updated simultaneously with all display pixels. The default display boundary value is stored at address E201 (hexadecimal) of the flash memory. For example, the display boundary value may be 0, 1, 2, 3 (black, gray 1, gray 2, white) and is represented by a low nibble of bytes at address E201. After reset, the default boundary value is read from the flash memory and recorded in the low nibble of the internal register and boundary data register (decimal address register). The high nibble of this register is set to 0 after reset. The low nibble in the boundary data register represents the new boundary value, and the high nibble represents the actual boundary value.

  At any time, the host can record the low nibble of this register using the controller's instruction record register (0x10), as well as the address register (0x12) and data. When this register is recorded, the current value of the low nibble is obtained for the high nibble, and the host data is obtained for the low nibble. Thus it can act like two images in memory and retain the previous and current display boundary values. For example, if the same value is recorded twice in the boundary data register, the display boundary is processed as a pixel with no transition. If the low nibble value is not equal to the high nibble value, the boundary is processed (updated) as a pixel having a transition from a “high nibble value” to a “low nibble value”. In this way, the boundary can be updated in all sequences or only during the refresh sequence. Furthermore, it is possible to change the boundary value at any desired time.

  While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various modifications and changes in form or detail may be readily made without departing from the spirit of the invention. Therefore, it should be noted that the present invention is not limited to the forms shown, but includes all modifications that come within the scope of the appended claims.

It is the figure which showed roughly the front view of the one part Example of the display screen of an electronic reader. FIG. 2 is a schematic cross-sectional view taken along line 2-2 in FIG. It is the figure which showed the outline of the electronic reader. FIG. 3 is a diagram schematically showing two display screens each having a display area. An algorithm for controlling a display in a plurality of image update modes. It is a figure which shows the data arrangement | sequence in memory. It is a figure which shows notionally the selection of the sequence based on the update mode of a display.

Claims (21)

A method of driving a display in a bistable device, comprising:
Storing coded data for different pixel transitions for driving the display;
Retrieving a portion of the stored encoded data based on at least a selected one of the different pixel transitions;
Decoding the portion of the stored encoded data to provide decoded data;
Providing at least one voltage waveform for driving the display based on the decoded data;
Having a method.   The method of claim 1, wherein the stored encoded data includes voltage level and timing information for each of the different pixel transitions. Storing the coded data comprises storing coded data for driving the display at different temperatures;
Retrieving the portion of the stored coded data comprises retrieving the portion of the coded data based on a selected one of the different temperatures. The method according to claim 1.   The method of claim 1, wherein retrieving the portion of the encoded data comprises retrieving at least one fixed length frame instruction.   2. The step of retrieving the portion of the coded data comprises retrieving the portion of the coded data based on a selected update mode of the display. the method of.   The method of claim 1, wherein the stored encoded data includes voltage level and timing information for each of the different pixel transitions and each of a plurality of different temperatures. further,
Storing a pointer to the stored encoded data for the different pixel transitions;
Storing relative address information for locating the stored encoded data driving the display at the plurality of different temperatures based on an offset from one of the corresponding pointers;
7. The method of claim 6, comprising: A device used in driving a display in a bistable device,
Means for retrieving a portion of the coded data from the memory based on at least one selected from a plurality of different pixel transitions;
Means for decoding the portion of the stored encoded data to provide decoded data;
Means for providing at least one voltage waveform for driving the display based on the decoded data;
And the stored encoded data includes data for the plurality of different pixel transitions for driving the display.   9. The apparatus of claim 8, wherein the encoded data includes voltage level and timing information for each of the plurality of different pixel transitions.   9. The apparatus of claim 8, wherein the means for retrieving retrieves the portion of the stored coded data in at least one fixed length frame instruction.   9. The apparatus of claim 8, wherein the searching means searches the portion of the stored coded data based on a selected update mode of the display. The stored encoded data includes data for driving the display at different temperatures;
9. The apparatus of claim 8, wherein the searching means searches the portion of the stored coded data based on a selected one of the different temperatures.   13. The apparatus of claim 12, wherein the stored encoded data includes voltage level and timing information for each of the different pixel transitions and each of the different temperatures.   9. The apparatus of claim 8, wherein the display comprises an electrophoretic display. A program storage device that implements an instruction program executable by a machine to perform a method of driving a display in a bistable device,
The method
Storing coded data for different pixel transitions for driving the display;
Retrieving a portion of the stored encoded data based on at least a selected one of the different pixel transitions;
Decoding the portion of the stored encoded data to provide decoded data;
Providing at least one voltage waveform for driving the display based on the decoded data;
A program storage device.   16. The program storage device of claim 15, wherein the stored encoded data includes voltage level and timing information for each of the different pixel transitions.   16. The program storage device according to claim 15, wherein the step of searching for the part of the coded data includes a step of searching for at least one fixed-length frame instruction.   16. The program according to claim 15, wherein the step of searching for the portion of the coded data searches for the portion of the coded data based on a selected update mode of the display. Storage device. Storing the coded data comprises storing coded data for driving the display at different temperatures;
Retrieving the portion of the stored coded data comprises retrieving the portion of the coded data based on a selected one of different temperatures. 16. The program storage device according to claim 15.   16. The program storage device of claim 15, wherein the stored encoded data includes voltage level and timing information for each of the different pixel transitions and each of a plurality of different temperatures. The method further comprises:
Storing a pointer to the stored encoded data for the different pixel transitions;
Storing relative address information for locating the stored encoded data driving the display at the plurality of different temperatures based on the corresponding offset from the pointer;
21. The program storage device according to claim 20, further comprising:

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