WO2016093144A1 - 表示制御装置、表示装置、および表示制御方法 - Google Patents
表示制御装置、表示装置、および表示制御方法 Download PDFInfo
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- WO2016093144A1 WO2016093144A1 PCT/JP2015/083988 JP2015083988W WO2016093144A1 WO 2016093144 A1 WO2016093144 A1 WO 2016093144A1 JP 2015083988 W JP2015083988 W JP 2015083988W WO 2016093144 A1 WO2016093144 A1 WO 2016093144A1
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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
- G09G3/2092—Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto
- G09G3/2096—Details of the interface to the display terminal specific for a flat panel
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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
- G09G3/3611—Control of matrices with row and column drivers
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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
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3618—Control of matrices with row and column drivers with automatic refresh of the display panel using sense/write circuits
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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
- G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
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- G—PHYSICS
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
- G09G5/36—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators characterised by the display of a graphic pattern, e.g. using an all-points-addressable [APA] memory
- G09G5/39—Control of the bit-mapped memory
- G09G5/393—Arrangements for updating the contents of the bit-mapped memory
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
- G09G5/36—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators characterised by the display of a graphic pattern, e.g. using an all-points-addressable [APA] memory
- G09G5/39—Control of the bit-mapped memory
- G09G5/395—Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen
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- G09G2300/04—Structural and physical details of display devices
- G09G2300/0439—Pixel structures
- G09G2300/0465—Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
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- G09G2310/08—Details of timing specific for flat panels, other than clock recovery
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
- G09G2330/02—Details of power systems and of start or stop of display operation
- G09G2330/021—Power management, e.g. power saving
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- G—PHYSICS
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
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- G09G2340/02—Handling of images in compressed format, e.g. JPEG, MPEG
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
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- G09G2360/00—Aspects of the architecture of display systems
- G09G2360/18—Use of a frame buffer in a display terminal, inclusive of the display panel
Definitions
- the present invention relates to a display control device that performs display control of a display device.
- a display device such as a personal computer or a smartphone generally includes a display controller that performs various display controls in order to appropriately output an image on the screen of the display unit.
- the display controller outputs the image data received from the host to the display device in accordance with the display timing of the display device.
- the display controller includes a display controller with a built-in memory and a display controller without a memory.
- a technique for driving a display unit at a high driving frequency has been developed in order to display a moving image or the like with higher quality.
- the present invention has been made in view of the above problems, and an object thereof is to realize a display control device, a display device, and a display control method that suppress power consumption related to display of image data.
- a display control device is a display control device that outputs image data for one frame received from a host to a display unit, and updates the image of the display unit.
- An information receiving unit that receives update information indicating whether or not to perform from the host, and writing the received image data into the memory and outputting the image data to the display unit corresponding to the update information
- a data processing unit that performs at least one of the following: when the device receives the image data, the data processing unit receives a first vertical synchronization period in which the image data is received or a second vertical When any one of the synchronization periods is set as a predetermined vertical synchronization period, when image update is performed in the predetermined vertical synchronization period, the image data is output without writing the image data, and If the image update is not performed in the constant of the vertical synchronization period, and wherein the writing of the image data.
- FIG. 3 is a diagram illustrating an input / output system for image data when writing, through output, and read output are performed in the display control device included in the display device according to the first embodiment.
- 3 is a timing chart illustrating various signal and data transmission / reception timings related to display control of the display device according to the first embodiment.
- FIG. 3 is a diagram illustrating a processing flow of the host and the display control device included in the display device according to the first embodiment. It is a figure which shows the modification of the timing chart shown in FIG. It is a block diagram which shows the principal part structure of the display apparatus which concerns on Embodiment 2 of this invention.
- FIG. 12 is a timing chart showing transmission / reception timings of various signals and data related to display control of the display device according to the second embodiment. It is a figure which shows the flow of a process of the host contained in the display apparatus which concerns on Embodiment 2, and the said display control apparatus. It is a timing chart which shows the vertical synchronizing signal in the display control apparatus contained in the display apparatus which concerns on Embodiment 3 of this invention, and the timing of input / output. 7 is a timing chart showing the timing of image data input / output with respect to the display control device when the vertical synchronization signal is delayed in the display control device.
- FIG. 1 is a block diagram showing a main configuration of a display device 500 according to this embodiment.
- the display device 500 includes a host 2, a display control device 1, and an LCD (display unit) 3.
- the host 2, the display control device 1, and the LCD 3 may be integrally configured as the display device 500, but may be separate devices.
- the host 2 generates image data to be displayed on the LCD 3 and provides it to the display control device 1.
- image data indicates image data for one frame displayed on the LCD 3.
- the host 2 transmits image data to the display control device 1 in synchronization with a TE (Tearing Effect) signal (described later) received from the display control device 1. More specifically, the host 2 includes a command generation unit 120, an image transmission unit 130, an update request acquisition unit 100, and an update determination unit 110.
- the update request acquisition unit 100 acquires an image update request from host 2 or application software (hereinafter simply referred to as “app”) running on an external device communicating with the host 2.
- the “image update request” is a request indicating that the image displayed on the LCD 3 (or the image to be displayed on the LCD 3) is updated in the frame period next to the frame period in which the image is displayed. is there.
- the update request acquisition unit 100 sends the acquired image update request to the update determination unit 110.
- the update determination unit 110 determines the type of command (update information) to be generated by the command generation unit 120 and the image data to be transmitted to the image transmission unit 130 according to the presence or absence of an image update request.
- the “command” is an instruction to the display control device 1 and is generated according to the presence or absence of an image update request as described above, that is, whether or not an image update is performed on the LCD 3.
- the update determination unit 110 instructs the command generation unit 120 to generate a through command when an image update request is obtained from the update request acquisition unit 100, that is, when there is an image update in the next frame period on the LCD 3.
- the through command is a command for instructing the display control device 1 to output image data to the LCD 3 without writing the image data in a memory (VRAM 50 described later).
- the update determination unit 110 also instructs the image transmission unit 130 to transmit the image data for update.
- the update determination unit 110 sends a write command (hereinafter referred to as a WR command) to the command generation unit 120. (Also described).
- the write command is a command for instructing the display control device 1 to write image data into the memory.
- the update determination unit 110 also instructs the image transmission unit 130 to retransmit the image data transmitted in the immediately preceding frame period.
- the command generation unit 120 generates a command and transmits it to the display control device 1.
- the command generation unit 120 generates a write command or a through command in response to an instruction from the update determination unit 110 and transmits it to the display control device 1.
- the image transmission unit 130 transmits image data according to an instruction from the update determination unit 110 to the display control device 1.
- the image data may be generated by the image transmission unit 130 or may be obtained from a storage device that the host 2 has or is connected to the host 2 so as to be able to perform data communication.
- the command may be communicated by being superimposed on the same interface as the image data, for example, DSI. In this case, both the command and the image data are transmitted from one functional block (interface) in which the command generation unit 120 and the image transmission unit 130 are combined.
- the display control device 1 is a device that outputs image data received from the host 2 to the LCD 3. More specifically, the display control device 1 is a controller that performs display control of the entire display device 500 by adjusting the input timing of image data of the host 2 and the display timing of image data of the LCD 3. More specifically, the display control device 1 includes a VRAM (memory) 50, a command receiving unit (information receiving unit) 10, an image receiving unit 20, a processing determining unit 30, a data processing unit 40, an internal timing generator ( (Internal TG, timing determination unit) 70 and read output unit 60.
- VRAM memory
- the display control device 1 includes a VRAM (memory) 50, a command receiving unit (information receiving unit) 10, an image receiving unit 20, a processing determining unit 30, a data processing unit 40, an internal timing generator ( (Internal TG, timing determination unit) 70 and read output unit 60.
- the VRAM 50 is a memory that stores image data.
- the image data is written by the writing unit 42, and the image data is read by a read output unit 60 described later.
- the VRAM 50 can be of any type as long as it can store image data (or compressed image data).
- the command receiving unit 10 receives commands from the command generating unit 120 of the host 2.
- the command receiving unit 10 sends the received command to the process determining unit 30.
- the image receiving unit 20 receives image data from the image transmitting unit 130 of the host 2.
- Specific examples of the command receiving unit 10 and the image receiving unit 20 include an interface conforming to the DSI (Display Serial Interface) standard of the MIPI (Mobile Industry Processor Interface, registered trademark) standard.
- the image receiving unit 20 sends the received image data to the output unit 41 and the writing unit 42 of the data processing unit 40.
- the process determination unit 30 determines a process to be performed by the data processing unit 40 according to the type of command obtained from the command generation unit 120.
- the processing determination unit 30 instructs the data processing unit 40 to perform through output in the next frame period.
- through output means that image data is output to the LCD 3 without being written to the VRAM 50.
- the processing determination unit 30 instructs the data processing unit 40 to write (write) image data to the VRAM 50 in the next frame period.
- the data processing unit 40 performs at least one of write and through output.
- the data processing unit 40 includes a writing unit 42 for writing image data and an output unit 41 for through output.
- the writing unit 42 writes image data in synchronization with a vertical synchronization signal generated by an internal TG 70 described later. Note that the writing unit 42 may write the image data after compressing the image data when the capacity of the image data is larger than the capacity of the VRAM 50.
- the output unit 41 outputs the image data received from the image receiving unit 20 through in synchronization with the vertical synchronization signal generated by the internal TG 70. Since the through output does not access the memory, it can be performed in parallel with the writing of the writing unit 42.
- the internal TG 70 generates a vertical synchronization signal (Vsync) for defining the input / output timing of image data.
- the output unit 41, the write unit 42, and a read output unit 60 described later perform through output, write, and read output in synchronization with Vsync generated by the internal TG 70, respectively.
- the internal TG 70 further transmits the generated Vsync to the host 2 as a TE signal.
- the TE signal is a signal composed of binary values of Low level and High level.
- the internal TG 70 controls the input timing of image data from the host 2 by transmitting a High level or Low level TE signal to the host 2.
- the host 2 starts transferring image data after a preset delay time from a predetermined edge of the TE signal. More specifically, the internal TG 70 transmits a high level TE signal during a vertical front porch (VF) period in one vertical synchronization period after the fall of the generated Vsync, and a low level TE signal during other periods
- the read output unit 60 performs read output.
- “read output” means reading the image data written in the VRAM 50 and outputting the image data to the LCD 3.
- the read output unit 60 performs read output in response to the fall of Vsync generated by the internal TG 70. More specifically, the read output unit 60 performs read output after the vertical back porch (VB) period after the falling edge and before the VF period of the next vertical synchronization signal.
- the read output unit 60 may decompress the image data into a format that can be displayed by the LCD 3 and output the decompressed data.
- the LCD 3 displays the image data output through or read from the display control device 1.
- the LCD 3 is preferably a liquid crystal display, but the configuration is not limited as long as the image data can be displayed.
- the LCD 3 may be a display device other than a liquid crystal display such as a display using a cathode ray tube (CRT), a plasma display, an organic EL (electroluminescence) display, and an electrolytic emission display.
- the LCD 3 includes a display screen having a plurality of pixels.
- the LCD 3 is an oxide semiconductor display panel as an active matrix display panel, for example.
- An oxide semiconductor display panel is a display panel that employs an oxide semiconductor-TFT (thin-film-transistor) as a switching element provided corresponding to at least one of a plurality of pixels arranged two-dimensionally. is there.
- An oxide semiconductor-TFT is a TFT in which an oxide semiconductor is used for a semiconductor layer.
- an oxide semiconductor for example, an oxide semiconductor using an oxide of indium, gallium, and zinc (InGaZnO-based oxide semiconductor) is given.
- An oxide semiconductor-TFT has a large current flowing in an on state and a small leak current in an off state. Therefore, by employing an oxide semiconductor-TFT for the switching element, the pixel aperture ratio can be improved and the refresh rate of the screen display can be reduced to about 1 Hz. The reduction of the refresh rate brings about a power saving effect.
- FIG. 2 is a diagram illustrating an input / output system of image data when the display control device 1 performs write, through output, and read output.
- the two “MIPI Rx” blocks in the figure are included in the command receiving unit 10 and the image receiving unit 20 in FIG. 1, and commands and image data transferred from the host 2 using MIPI data transfer specifications. Is to be received.
- the “compression” and “write control” blocks in the drawing are included in the writing unit 42 in FIG. 1, and the “read control” block is included in the output unit 41.
- the “decompressing” block is included in the output unit 41 and the read output unit 60.
- the “compression” and “decompression” blocks are not essential. “TG for MIPI clk” extracts timing information of image data from MIPI Rx and transmits the timing information to the through output unit.
- the display control apparatus 1 processes image data in at least one of (1) through system, (2) write system, and (3) read system.
- the through system and the lead system may use a partially common system path ((1 ′) through / lead system).
- the through system is a system that through-outputs the image data received from the host 2 by the display control device 1 (image receiving unit 20).
- the display control device 1 processes the image data in the through system.
- the output unit 41 of the data processing unit 40 outputs (through output) the image data received via the MIPI Rx to the LCD 3 in synchronization with the timing information extracted by the TG for MIPI clk.
- the output unit 41 decompresses the image data via (1 ′) through / read system and outputs it to the LCD 3 as shown in the figure. That's fine.
- the through system is a processing system that does not accompany access to the VRAM 50. Therefore, the through system and the write system described below can be processed in parallel.
- the write system is a system for writing the image data received from the host 2 to the VRAM 50 by the display control device 1.
- the display control device 1 processes the image data in the light system.
- the writing unit 42 of the data processing unit 40 writes the image data received via the MIPI Rx (image receiving unit 20) into the VRAM 50 in synchronization with Vsync generated by the internal TG 70 (“write control”). "block).
- the writing unit 42 may compress the image data (“compressed” block) and then write it to the VRAM 50.
- the read output unit 60 reads image data from the VRAM 50 (“read control” block), decompresses it as necessary (“decompression” block), and outputs it to the LCD 3. At this time, the read output unit 60 reads image data from the VRAM 50 in synchronization with Vsync generated by the internal TG 70. Then, the read output unit 60 outputs the read image data to the LCD 3 in synchronization with Vsync.
- the update determination unit 110 sends the next frame to the command generation unit 120.
- a command indicating that “no image update is performed” (update information indicating that there is no image update) may be generated and transmitted during the period.
- the command receiving unit 10 of the display control device 1 transmits the command to the process determining unit 30, and the process determining unit 30 instructs the read output unit 60 to perform a read output. I do.
- FIG. 3 is a timing chart showing transmission / reception timings of various signals and data related to display control of the display device 500.
- a vertical column in FIG. 3 indicates one frame period defined by the display control device 1.
- the “update” line indicates whether or not the update request acquisition unit 100 has acquired an image update request from the application in each frame period by the presence or absence of a downward arrow.
- the “WR command” line indicates the timing at which the command receiving unit 10 of the display control apparatus 1 receives the WR command with a downward arrow.
- the “DSI input” line indicates the timing and period when the image receiving unit 20 which is an interface conforming to DSI receives image data (an image is input from the host 2 to the image receiving unit 20). Blocks with alphabets in the “DSI input” line indicate image data, and blocks with the same alphabets indicate the same image data. In FIG. 3, for the sake of convenience, the reception period of the image data is described as if it were the same length as one frame period, but the image data is actually received (transferred) in a period shorter than one frame period. .
- the “RAM WR” line indicates the timing and period during which the writing unit 42 of the display control device 1 writes image data to the VRAM 50 with “W” added thereto.
- the “RAM RD” line indicates the timing and period during which the read output unit 60 reads image data from the VRAM 50 with a block marked with “R”.
- the “W” block and the “R” block are described as if they have the same length as one frame period, but the image data is actually written or written in a period shorter than one frame period.
- the “LCD drive” row indicates the drive timing of the LCD 3, that is, the display timing and display update period of the image data on the LCD 3.
- the display update period of image data is described as if it is the same length as one frame period, but this is not essential.
- the update request acquisition unit 100 acquires the presence / absence of an image update request from the application for each frame period.
- the update determination unit 110 that has received the image update request from the update request acquisition unit 100 in the LCD 3 in the next frame period of the current frame period. It is determined that an image update is necessary, and instructions are sent to the command generation unit 120 and the image transmission unit 130, respectively.
- a through command is generated by the command generation unit 120 and transmitted to the command reception unit 10.
- image data (for update) is transmitted from the image transmission unit 130 to the image reception unit 20.
- the host 2 stores the transmitted image data (hereinafter referred to as transmitted image data) in, for example, a storage device (not shown).
- the update request acquisition unit 100 acquires an image update request (arrow B in the “update” row). Therefore, the command generation unit 120 transmits a through command to the command reception unit 10 of the display control apparatus 1, and the image transmission unit 130 transmits image data B for update to the image reception unit 20 in the next frame, and receives the image.
- the unit 20 receives this ("DSI input" line of f2). At this time, the host 2 stores the transmitted image data B in a storage device (not shown) or the like.
- the data processing unit 40 performs the image update when the image update is performed in the vertical synchronization period f2 (first vertical synchronization period) in which the reception of the image data B is completed.
- the image data B is output to the LCD 3 without writing the data B to the VRAM 50 (“LCD drive” line of f2).
- the command generation unit 120 transmits the received through command to the processing determination unit 30.
- the processing determination unit 30 instructs the data processing unit 40 to perform through output corresponding to the type of command.
- the output unit 41 of the data processing unit 40 receives the instruction and outputs the image data B through. As a result, the image data B can be displayed on the LCD 3 without writing to the VRAM 50 and reading from the VRAM 50 (“LCD drive” line of f2).
- the update determination unit 110 determines that there is no image update from the next frame of the frame, and sends instructions to the command generation unit 120 and the image transmission unit 130, respectively. .
- a write command is generated by the command generator 120 and transmitted to the command receiver 10.
- the image transmission unit 130 reads the transmitted image data stored in the host 2 and retransmits it to the image reception unit 20 of the display control device 1.
- the update request acquisition unit 100 has not acquired an image update request (the “update” line of f2 is blank). Accordingly, the command generation unit 120 transmits a write command to the command reception unit 10 (the arrow in the “WR command” line of f2), and the image transmission unit 130 transmits the transmitted image data (image data B) by the end of the frame period of f3. ) Is retransmitted to the display control apparatus 1 ("DSI input" line of f3).
- the command receiving unit 10 that has received the write command transmits the command to the process determining unit 30, and the process determining unit 30 instructs the data processing unit 40 to write the transmitted image data B during f3.
- the writing unit 42 of the data processing unit 40 receives the instruction and writes the transmitted image data B in the VRAM 50 in the frame period f3 ("RAM WR" line of f3).
- the data processing unit 40 displays the image in the vertical synchronization period f3 (first vertical synchronization period) in which the re-reception of the transmitted image data B is completed.
- the transmitted image data B is not output to the LCD 3 and the transmitted image data B is written to the VRAM 50.
- the read output unit 60 of the display control device 1 is driven to read the transmitted image data from the VRAM 50.
- the VRAM 50 stores the image data G written in the frame before f4. Therefore, the read output unit 60 reads the image data G from the VRAM 50 (“RAM RD” line of f4) and outputs it to the LCD 3 (“LCD output” line of f4).
- the display device 500 switches between through output, write, and read output for each frame in accordance with the presence / absence of an image update request and the passage of a predetermined frame period.
- the image data can be output to the LCD 3 without going through the VRAM 50.
- the transmitted image data can be retransmitted to the display control device 1 when the image update stops, and the retransmitted data can be written in the VRAM 50.
- the read output unit 60 performs the read output even when the host 2 does not operate, thereby displaying the transmitted image data on the LCD 3 (LCD 3 Display can be refreshed).
- display quality can be maintained by refreshing at a minimum of 60 Hz.
- the refresh rate can be reduced to about 1 Hz while maintaining display quality.
- the predetermined frame period described above can be set to 59 frame periods, for example.
- FIG. 4 is a diagram showing a flow of through output and write determination processing of the host 2 and the display control device 1 in the control example shown in FIG.
- the command generation unit 120 When the update request acquisition unit 100 of the host 2 receives an image update request from the application within one frame period (YES in S100), the command generation unit 120 generates a through command (S102). On the other hand, when the update request acquisition unit 100 does not receive an image update request within one frame period (NO in S100), the update determination unit 110 causes the command generation unit 120 to generate a write command (S104). The command generation unit 120 transmits the generated command (S106), and the command reception unit 10 of the display control apparatus 1 receives this (S200, information reception step) and sends it to the processing determination unit 30.
- the update determination unit 110 causes the image transmission unit 130 to transmit image data corresponding to the type of transmitted command.
- the update determination unit 110 causes the image transmission unit 130 to transmit image data for update (S110).
- the update determination unit 110 retransmits the transmitted data to the image transmission unit 130 (S112).
- the image receiving unit 20 of the display control device 1 receives the update image data or the transmitted image data (S202), it sends it to the data processing unit 40.
- the data processing unit 40 processes the image data in accordance with an instruction from the processing determination unit 30. That is, when the command received from the host 2 is a through command (S204), the output unit 41 of the data processing unit 40 performs through output (S206, data processing step). On the other hand, when the command received from the host 2 is a write command (S204), the writing unit 42 writes the transmitted image data to the VRAM 50 (S208, data processing step).
- the host 2 transmits the transmitted image data from the image transmission unit 130 as soon as the image update request from the application is not acquired in a certain frame.
- the LCD 3 is a device that can change the frame rate
- the host 2 does not immediately transmit the transmitted image data to the display control device 1 but instead the minimum frame of the LCD 3.
- the transmitted image data may be retransmitted at any timing during the rate period.
- FIG. 5 is a diagram showing a modification of the timing chart shown in FIG.
- the LCD 3 is a device that can change the refresh rate. Specifically, it is desirable that the LCD 3 can change the frame rate from a low frequency of about 1 Hz to a high frequency of about 120 Hz.
- FIG. 5 illustrates a case where the LCD 3 is normally driven at a refresh rate of 120 Hz and the minimum refresh rate is 60 Hz.
- the update determination unit 110 determines that there is no image update in the next frame of the frame. Then, the update determination unit 110 waits for a predetermined period of the minimum frame rate (60 Hz) of the LCD 3 (that is, the longest refresh interval that the LCD 3 can take). The update determination unit 110 instructs the image transmission unit 130 to transmit the transmitted image data after approximately 1/60 second (maximum refresh cycle) has elapsed since the start of transmission of the image data. In the example of FIG. 5, the LCD 3 is driven based on a vertical synchronizing signal of 120 Hz, and its minimum frame rate is 60 Hz.
- the update determination unit 110 waits for the next one frame period after f5.
- the update determination unit 110 instructs the command generation unit 120 to generate a through command, and instructs the image transmission unit 130 to transmit update image data.
- the update determination unit 110 instructs the command generation unit 120 to generate a write command, and transmits the transmitted image data to the display control device 1 to the image transmission unit 130.
- an image update request is not obtained in f6, which is the next frame period after f5.
- the command generation unit 120 generates a write command (“WR command” line of f6), and the image transmission unit 130 retransmits the transmitted image data (image data G) to the display control device 1. Then, the writing unit 42 of the display control device 1 writes the transmitted image data (image data G) to the VRAM 50 (“RAM WR” line of f6).
- the update determination unit 110 issues an instruction to the command generation unit 120 and the image transmission unit 130 after the minimum frame rate period of the LCD 3 has elapsed.
- the same instruction as described is given to the command generation unit 120 and the image transmission unit 130, and the command generation unit 120 and the image transmission unit 130 generate the command and transmit the transmitted image until the minimum frame rate period of the LCD 3 elapses.
- the minimum refresh rate of the LCD 3 is 1 Hz
- the image transmission unit 130 transmits the transmitted image data after 1 second (maximum refresh cycle) has elapsed since the start of image data transmission. Also good.
- FIG. 6 is a diagram illustrating a main configuration of the display device 600 according to the present embodiment.
- the display device 600 includes a host 5, a display control device 4, and an LCD 3.
- the host 5 is different from the host 2 according to the first embodiment in that it includes an update information buffer 140.
- the update information buffer 140 stores whether or not the update request acquisition unit 100 has acquired an image update request and, if acquired, the image update request for a predetermined frame period.
- the update information buffer 140 stores the presence / absence of an image update request for at least one frame period.
- the host 2 sequentially reads out image update requests stored in the update information buffer 140, and transfers image data (that is, image update in the LCD 3) in response to the requests.
- the update determination unit 111 uses the command generation unit 121 based on whether there is an image update request in the previous frame period of the current frame period and whether there is an image update request in the current frame period. And an instruction to the image transmission unit 131 is determined. Specifically, the update determination unit 111 first refers to the update information buffer 140 to determine whether or not there has been an image update in the frame period immediately before the current frame period. If the update information buffer 140 stores that there is an image update, the update determination unit 111 instructs the image transmission unit 131 to transmit image data for update. That is, the update determination unit 111 instructs the image transmission unit 131 to transmit image data in response to an image update request obtained in the frame period immediately before the current frame period, not in the current frame.
- the update determination unit 111 processes the image update request after delaying it by one frame period.
- the update determination unit 111 further has an image update in the current frame period based on whether or not the image update request (image update request to be stored in the update information buffer 140) acquired from the update request acquisition unit 100 in the current frame period has been obtained. It is determined whether or not.
- the update determination unit 111 receives the command generation unit 121. Is instructed to generate a through command.
- the update request acquisition unit 100 obtains an image update request and stores it in the update information buffer 140.
- the update determination unit 111 instructs the command generation unit 121 to Instructs to generate a write-through command.
- the “write and through command” is a command for instructing both writing of image data to the VRAM 50 and through output.
- the command generation unit 121 generates a write & through command according to an instruction from the update determination unit 111 and transmits it to the display control device 4.
- the update determination unit 111 uses the command generation unit. It waits until the next frame period without giving an instruction to 121 and the image transmission unit 131.
- FIG. 7 is a timing chart showing transmission / reception timings of various signals and data related to display control of the display device 600.
- FIG. 7 the description of the parts that perform the same processing as in FIG. 3 is omitted.
- the “update” row in FIG. 7 indicates whether or not the update request acquisition unit 100 has acquired an image update request from the application in each frame period by the presence or absence of a downward arrow.
- the “update_d” line indicates the presence or absence of an image update request read from the update information buffer 140 by the update determination unit 111 by the presence or absence of a downward arrow.
- the “WR & TH command” line indicates a timing at which the command receiving unit 10 of the display control device 4 receives the write & through command with a downward arrow.
- the update determination unit 111 causes the command generation unit 121 to generate a through command and transmits the through command to the display control device 4, and in response to the image update request for the previous frame period, The image data A for output (image update) is transmitted to the LCD 3 during the frame period.
- the image receiving unit 20 of the display control device 4 completes the reception of the image data A by the end of the frame period of f8 (“DSI input” line of f8), and the command receiving unit 10 receives the through command.
- the processing determining unit 30 causes the data processing unit 40 to perform through output within the period of f8 (“LCD drive” line of f8).
- the data processing unit 40 displays the image in the vertical synchronization period f9 (second vertical synchronization period) next to the vertical synchronization period f8 in which the reception of the image data A is completed.
- the image data A is output to the LCD 3 without writing the image data A to the VRAM 50.
- the image update request (arrow B in the “update” row of f7) obtained by the update request acquisition unit 100 in the frame period (f7) before f8 is stored in the update information buffer 140, and in the frame period f8.
- the data is read out by the update determination unit 111 (arrow B in the “update_d” row).
- the update determination unit 111 issues an instruction to the command generation unit 121 and the image transmission unit 131 based on the read image update request, the display that receives the command from the command generation unit 121 and the image data from the image transmission unit 131 is displayed.
- the control device 4 performs the image update in the frame period f9. Therefore, the data processing unit 40 outputs the image data A to the LCD 3 without writing the image data A to the VRAM 50 in the frame period f9.
- the update determination unit 111 causes the command generation unit 121 to generate and transmit a write & through command and updates the image transmission unit 131 in the f9 frame period in response to the image update request of the previous frame period.
- Image data B is transmitted.
- the command receiving unit 10 of the display control device 4 receives the write & through command (“WR & TH command” line in f9), and the image receiving unit 20 receives the image data B (“DSI input” line in f9).
- the processing determination unit 30 obtains the write & through command from the command receiving unit 10, the processing unit 30 writes the image data A to the VRAM 50 ("RAM WR" line of f9) and the through output ("LCD of f9" LCD). Drive "line).
- the data processing unit 40 updates the image in the vertical synchronization period (second vertical synchronization period) next to the vertical synchronization period f9 in which the reception of the image data B is completed. If not, the image data B is output to the LCD 3 and the image data B is written to the VRAM 50.
- FIG. 8 is a flowchart showing the flow of through output and write & through output determination processing of the host 5 and the display control device 4 in the control example shown in FIG.
- the update request acquisition unit 100 of the host 5 Upon receiving an image update request from the application, the update request acquisition unit 100 of the host 5 stores the image update request in the update information buffer 140 and transmits it to the update determination unit 111.
- the update determination unit 111 determines whether there is an image update request in the frame period immediately before the current frame period by referring to the update information buffer 140 (S300). If there is an image update request in the previous frame period of the current frame period (YES in S300), the update determination unit 111 instructs the image transmission unit 131 to transmit image data for update and an update request acquisition unit. It is further determined whether an image update request has been obtained from 100 (that is, whether an image update request has been obtained from the application during the current frame period) (S302).
- the update request acquisition unit 100 stores the presence / absence of an image update request in the current frame period in the update information buffer 140, and updates The determination unit 111 waits until the next frame period.
- the update determination unit 111 uses the command generation unit.
- the command generation unit 121 generates a through command by instructing 121 to generate a through command (S304).
- the update determination unit 111 instructs the command generation unit 121 to generate a write & through command, and the command generation unit 121. Generates a write & through command (S306).
- the command generation unit 121 transmits the created command to the image reception unit 20 of the display control device 4 (S308), and the image transmission unit 131 sends image data for update to the display control device 4 in accordance with an instruction from the update determination unit 111. Transmit (S310).
- the command reception unit 10 of the display control device 4 receives the command from the command generation unit 121 (S400, information reception step) and sends it to the processing determination unit 30.
- the image receiving unit 20 receives image data for update (S402).
- the process determining unit 30 determines the process of the data processing unit 40 according to the type of command obtained from the command receiving unit 10 (S404). When the obtained command is a through command (“through command” in S404), the process determination unit 30 instructs the data processing unit 40 to output through, and the output unit 41 of the data processing unit 40 performs through output (S406, Data processing step).
- the process determination unit 30 gives both the through output and the image data write to the VRAM 50 to the data processing unit 40. Instruct to do.
- the data processing unit 40 performs through output in the output unit 41, and writes image data to the VRAM 50 in the writing unit 42 (S408, data processing step).
- the display control apparatus 1 (or the display control apparatus 4) outputs image data to the LCD 3 using either a through output or a read output system.
- the display control device 1 has a through system. A collision with the lead system will occur.
- the command generation unit 120 of the host 2 may transmit image data for output in the next frame period in the VF period of the display control apparatus 1. The processing for avoiding the collision of the output system in the present embodiment will be described below with reference to FIGS. FIG.
- FIG. 9 is a timing chart showing the vertical synchronization signal and the input / output timing in the display control apparatus 1.
- FIG. 9A shows a case where a collision of the output system can occur
- FIG. 9B shows a configuration example in which the collision is avoided.
- the display control device 1 and the host 2 according to the first embodiment will be described as an example, but the configuration according to the present embodiment may be applied to the second embodiment.
- the “Internal TG” line indicates the fall of Vsync.
- the “read output” line indicates a read output timing and an output period scheduled in the display control apparatus 1.
- the “input from the host” line indicates the timing and input period when image data is transferred (input) from the host 2.
- the “LCD” line indicates the actual output timing and output period of image data from the display control device 1 to the LCD 3.
- the arrow in a figure shows the timing when the display control apparatus 1 received the through command. As shown in (a) of FIG.
- the host 2 may transfer the command and the image data for update in the next frame period earlier than the read output unit 60 performs the read output. More precisely, it is desirable that the host 2 transfers the update image data during the VF period of the frame period immediately before the update of the image data. This is because the VF period is a period during which no read output is performed in the display control apparatus 1, so that there is no collision of access to the VRAM 50. As described in the first embodiment, the host 2 starts transferring image data after a predetermined delay time from a predetermined edge of the TE signal.
- the host 2 sets the delay time so that the timing “after a predetermined delay time from the predetermined edge of the TE signal” is in the VF period, thereby transferring the image data during the VF period. Can start. In this case, it is desirable that the host 2 inputs a through command for the next frame period before the VF period. Thereby, the process determination unit 30 of the display control apparatus 1 can determine the output system in the next frame period from the command received before the VF period. The data processing unit 40 can output the update image data received during the VF period without colliding with the read output performed by the read output unit 60.
- the image data B is output without passing through the VRAM 50, and the output starts simultaneously with the input of the image data B.
- Image data output is started earlier than the case.
- the internal TG 70 of the display control apparatus 1 synchronizes the time when the reception of the image data B is started and the fall of the Vsync.
- FIG. 10 is a timing chart showing image data input / output timing with respect to the display control device 1 when the display control device 1 delays the vertical synchronization signal (Vsync).
- Vsync vertical synchronization signal
- the display control device 1 stands by without performing the read output by the read output unit 60.
- the image data in FIG. 10, for example, the maximum refresh period of the LCD 3 within a predetermined period (the time that does not cause a problem in the display of the image data on the LCD 3) since the start of output of the image data to the LCD 3.
- the internal TG 70 synchronizes the fall of Vsync with the input start timing.
- the read output unit 60 of the display control device 1 outputs the image data A2 to the LCD 3 by read output.
- the display control apparatus 1 performs the read output and the through output. Collisions can be avoided.
- control blocks (particularly, the update determination unit 110, the update determination unit 111, and the processing determination unit 30) of the host 2 or 5 and the display control device 1 or 4 are logical circuits (hardware) formed in an integrated circuit (IC chip) or the like. Hardware), or software using a CPU (Central Processing Unit).
- the display control device 1 includes a CPU that executes instructions of a program that is software that realizes each function, and a ROM (Read Only Memory) in which the program and various data are recorded so as to be readable by the computer (or CPU).
- a storage device (these are referred to as “recording media”), a RAM (Random Access Memory) for expanding the program, and the like are provided.
- the objective of this invention is achieved when a computer (or CPU) reads the said program from the said recording medium and runs it.
- a “non-temporary tangible medium” such as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used.
- the program may be supplied to the computer via an arbitrary transmission medium (such as a communication network or a broadcast wave) that can transmit the program.
- a transmission medium such as a communication network or a broadcast wave
- the present invention can also be realized in the form of a data signal embedded in a carrier wave in which the program is embodied by electronic transmission.
- a display control device (display control device 1 or 4) according to aspect 1 of the present invention is a display control device that outputs image data for one frame received from a host (host 2 or 5) to a display unit (LCD 3).
- the information receiving unit (command receiving unit 10) that receives update information (command) indicating whether or not to update the image on the display unit from the host, and the received image data corresponding to the update information
- a data processing unit (data processing unit 40) that performs at least one of writing to the memory (VRAM 50) and outputting the image data to the display unit.
- the predetermined vertical synchronization is performed.
- the image data is not written but the image data is output (through output).
- the image data is written ( Write).
- the first vertical synchronization period indicates a vertical synchronization period at the time when the display control apparatus completes reception of image data.
- the data processing unit determines whether there is an image update in a predetermined vertical synchronization period, that is, the current vertical synchronization period (current frame period), or the next vertical synchronization period (next).
- the data processing unit can reduce the power required for writing image data to the memory by outputting the image data without writing it to the memory when there is an image update.
- the data processing unit re-sends the image data from the host each time when it is desired to re-output the image data for refreshing the display unit by temporarily writing the image data into the memory.
- the image data written in the memory can be read out. Therefore, it is possible to reduce power related to reception of image data. From the above, the display control apparatus can suppress power consumption related to display of image data on the display unit.
- the predetermined vertical synchronization period may be the first vertical synchronization period.
- the data processing unit if there is an image update in the current vertical synchronization period (current frame period) when the image data is received, the data processing unit outputs the image data without going through the memory.
- the display control device can particularly suppress the power required for writing data to the memory.
- the display control apparatus provides the display control device according to aspect 2 from the host when the image processing is not performed for a predetermined period after the data processing unit outputs the image data to the display unit.
- the retransmitted image data may be written in the memory.
- the data processing unit re-receives the image data from the host and writes it in the memory when the image is not updated for a predetermined period.
- the “predetermined period” referred to here is, for example, a refresh interval of the display unit.
- the predetermined vertical synchronization period may be the second vertical synchronization period.
- the data processing unit does not write the image data to the memory when there is an image update in the next vertical synchronization period (next frame period) after the current vertical synchronization period (current frame period) in which the image data is received. Output.
- the fact that there is an image update in the next frame period means that the image data received in the current frame period is not used for refreshing the display unit later. Therefore, the data processing unit can output the image data that is not used for refresh without writing to the memory as described above, thereby reducing the frequency of extra data writing to the memory. Therefore, the display control apparatus can reduce power consumption required for writing data to the memory.
- the data processing unit does not perform the image update in the second vertical synchronization period, and performs the image update in the first vertical synchronization period.
- the image data may be written to the memory and the image data may be output to the display unit.
- the data processing unit outputs the image data to the memory in preparation for refreshing the display unit while outputting the image data to the display unit when there is no image update from the next frame period (at least for one frame period). Can be written.
- the display control device is the display control apparatus according to any one of the aspects 1 to 5, wherein the data processing unit outputs the image data to the display unit, and the image update is not performed.
- a read output unit (read output unit 60) that reads out the image data from the memory and outputs the image data to the display unit when time has elapsed may be provided.
- the read output unit uses the image data written in the memory without receiving the image data from the host every time when outputting the image data periodically by refreshing the display unit or the like.
- the display unit can be refreshed. Therefore, the display control apparatus can reduce power consumption related to reception of image data.
- the data processing unit starts receiving the image data from the host within the vertical front porch period of the first vertical synchronization period, and the image Output of data to the display unit may be started.
- the data processing unit starts receiving image data from the host and starts outputting to the display unit during a vertical front porch period in which reading of image data from the memory does not occur. Accordingly, the data processing unit can prevent the output of the image data performed by itself from colliding with the output of the image data read from the memory by the read output unit.
- the data processing unit may receive the update information before the vertical front porch period of the first vertical synchronization period.
- the data processing unit can receive the update information before receiving the image data. Therefore, the data processing unit can determine in advance whether or not to output the image data without going through the memory before receiving the image data.
- the display control apparatus determines whether to update the image on the display unit with the output from the data processing unit or to refresh the display unit with the output from the readout output unit by the reception and output timing of the image data. I can leave. Therefore, it is possible to prevent a collision between the output of the image data by the data processing unit and the output of the image data (image data written in the memory) by the readout output unit.
- the display control apparatus is the timing determination unit (internal TG 70) for determining the output timing of the image data to the display unit in the aspect 7 or 8, wherein the first vertical synchronization period.
- a timing determination unit that delays the drive timing of the display unit until the device itself receives the image data may be provided.
- the timing determination unit is configured to receive the image data even when the display control device cannot start receiving the image data within the vertical front porch period due to a synchronization error with the host or a reception delay of the image data.
- the decision on whether to update the display unit image with the output from the data processing unit or to refresh the display unit with the output from the readout output unit is postponed can do. Therefore, even when the display control device cannot start receiving image data within the vertical front porch period, the display control device outputs the image data by the data processing unit and the image data (written to the memory by the read output unit). Collision with the output of the image data) can be prevented.
- the display device includes the display control device (display control device 1 or 4) according to any one of the above aspects 1 to 9.
- the display device has the same effects as the display control device according to the first to ninth aspects.
- a display control method for a display control device is a display control device (display control device 1 or 1) that outputs image data for one frame received from a host (host 2 or 5) to a display unit (LCD 3). 4) a display control method, wherein an update information (command) indicating whether or not to update an image on the display unit is received from the host in an information reception step (S200 or S400), and the information reception step.
- the display control method has the same effect as the display control device according to the first aspect.
- the present invention can be used for a display control device in a display device having a display unit such as a mobile phone or a personal computer.
- the present invention can be suitably used in a display control device that performs display control of a display unit that can change a drive frequency.
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Abstract
Description
本発明の第1の実施形態について説明すれば、以下の通りである。
図1は、本実施形態に係る表示装置500の要部構成を示すブロック図である。表示装置500は、ホスト2と、表示制御装置1と、LCD(表示部)3とを含む。なお、ホスト2、表示制御装置1、およびLCD3は表示装置500として一体に構成されていてもよいが、それぞれ別個の装置であってもよい。
ホスト2は、LCD3に表示させる画像データを生成し、表示制御装置1に提供するものである。ここで、「画像データ」とは、LCD3に表示する1フレーム分の画像のデータを示す。ホスト2は表示制御装置1から受信するTE(Tearing Effect)信号(後述)に同期して、表示制御装置1へ画像データを送信する。ホスト2は、さらに詳しくは、コマンド生成部120と、画像送信部130と、更新要求取得部100と、更新判定部110とを含む。
表示制御装置1は、ホスト2から受信した画像データをLCD3へと出力する装置である。より詳しくは、表示制御装置1はホスト2の画像データの入力タイミングと、LCD3の画像データの表示タイミングとを調整することにより、表示装置500全体の表示制御を行うコントローラである。表示制御装置1は、さらに詳しくは、VRAM(メモリ)50と、コマンド受信部(情報受信部)10と、画像受信部20と、処理判定部30と、データ処理部40と、内部タイミングジェネレータ(内部TG、タイミング決定部)70と、読出出力部60とを含む。
LCD3は、表示制御装置1からスルー出力またはリード出力された画像データを表示する。LCD3は液晶ディスプレイ(Liquid Crystal Display)であることが望ましいが、上記画像データが表示可能あればその構成は限定されない。例えばLCD3は、ブラウン管を用いたディスプレイ(CRT)、プラズマディスプレイ、有機EL(electroluminescence)ディスプレイ、電解放出ディスプレイなど、液晶ディスプレイ以外の表示装置であってもよい。
以下、表示制御装置1が行うライト、スルー出力、およびリード出力それぞれにおける画像データの入出力の流れについて、図2を用いて詳細に説明する。図2は、表示制御装置1においてライト、スルー出力、およびリード出力を行う場合の、画像データの入出力の系統を示す図である。
スルー系は、表示制御装置1(画像受信部20)がホスト2から受信した画像データをスルー出力する系統である。表示制御装置1はホスト2から受信したコマンドがスルーコマンドである場合、スルー系で画像データを処理する。
ライト系は、表示制御装置1がホスト2から受信した画像データをVRAM50にライトする系統である。表示制御装置1はホスト2から受信したコマンドがWRコマンドである場合、ライト系で画像データを処理する。
(1)スルー系および(2)ライト系は、ホスト2からのコマンドおよび画像データの受信により処理が開始される。一方、(3)リード系は(1)スルー系および(2)ライト系とは異なり、LCD3の垂直同期期間の開始までに画像更新を示すホスト2からのコマンド入力および画像データ入力が無かった場合に実行される処理系統である。
次に、表示装置500(特に、ホスト2および表示制御装置1)が行う表示制御処理の流れについて、図3を用いて説明する。図3は、表示装置500の表示制御に係る各種信号およびデータの送受信のタイミングを示すタイミングチャートである。図3の縦1列は、表示制御装置1が規定する1フレーム期間を示す。
最後に、図3に示した制御例における、スルー出力とライトとの切替えに係る処理の流れを、図4を用いて説明する。図4は、図3に示す制御例におけるホスト2および表示制御装置1のスルー出力およびライトの判定処理の流れを示す図である。
図3およびその説明では、ホスト2は、あるフレームでアプリからの画像更新要求を取得しなかった場合すぐに、画像送信部130から送信済画像データを送信した。しかしながら、LCD3がフレームレートを変更可能な装置である場合、ホスト2は画像更新要求を取得しなかった場合、すぐに送信済画像データを表示制御装置1に送信するのではなく、LCD3の最小フレームレートの期間中のいずれかのタイミングで送信済画像データを再送すればよい。以下、図3の制御例の変形例について図5を用いて説明する。なお、図5において、図3と同様の処理を行う箇所については説明を省略する。図5は、図3に示したタイミングチャートの変形例を示す図である。
本発明の他の実施形態について、図6~図8に基づいて説明すれば、以下のとおりである。なお、説明の便宜上、前記実施形態にて説明した部材と同じ機能を有する部材については、同じ符号を付記し、その説明を省略する。
図6は、本実施形態に係る表示装置600の要部構成を示す図である。図示の通り、表示装置600はホスト5と、表示制御装置4と、LCD3とを備える。ホスト5は、更新情報バッファ140を備える点において、実施形態1に係るホスト2と異なる。更新情報バッファ140は、更新要求取得部100が画像更新要求を取得したか否かと、取得した場合当該画像更新要求とを所定のフレーム期間の分だけ記憶するものである。更新情報バッファ140は、少なくとも1フレーム期間分、画像更新要求の有無を記憶する。ホスト2は、更新情報バッファ140に記憶させた画像更新要求を順次読出し、当該要求に応じて画像データの転送(すなわち、LCD3における画像更新)を行う。
次に、表示装置600が行う表示制御処理について図7を用いて説明する。図7は、表示装置600の表示制御に係る各種信号およびデータの送受信のタイミングを示すタイミングチャートである。なお、図7において図3と同様の処理を行う箇所については説明を省略する。
最後に、図7に示した制御例における、スルー出力とライトとの切替えに係る処理の流れを、図8を用いて説明する。図8は、図7に示す制御例におけるホスト5および表示制御装置4のスルー出力と、ライト&スルー出力の判定処理との流れを示すフローチャートである。
ところで、表示制御装置1(または表示制御装置4)は、スルー出力またはリード出力いずれかの系路を用いてLCD3に画像データを出力する。ここで、あるフレーム期間において画像データのリード出力を行おうとしている所にホスト2(またはホスト5)からスルーコマンドおよび画像データが転送されてきた場合、表示制御装置1の内部では、スルー系とリード系との衝突が起こることとなる。このような出力系の衝突を回避するため、ホスト2のコマンド生成部120は、次のフレーム期間の出力のための画像データを表示制御装置1のVF期間に送信してもよい。以下、図9~10を用いて、本実施形態における上記出力系の衝突回避のための処理について説明する。図9は、表示制御装置1における垂直同期信号と、入出力のタイミングとを示すタイミングチャートである。図9の(a)は、出力系の衝突が起こり得る場合を示しており、図9の(b)は当該衝突を回避した構成例を示す。なお、以降は実施形態1に係る表示制御装置1およびホスト2を例にとり説明するが、本実施形態に係る構成を実施形態2に適用してもよい。
ホスト2または5、ならびに表示制御装置1または4の制御ブロック(特に更新判定部110、更新判定部111、および処理判定部30)は、集積回路(ICチップ)等に形成された論理回路(ハードウェア)によって実現してもよいし、CPU(Central Processing Unit)を用いてソフトウェアによって実現してもよい。
本発明の態様1に係る表示制御装置(表示制御装置1または4)は、ホスト(ホスト2または5)から受信した1フレーム分の画像データを表示部(LCD3)に出力する表示制御装置であって、上記表示部の画像更新を行うか否かを示す更新情報(コマンド)を上記ホストから受信する情報受信部(コマンド受信部10)と、上記更新情報に対応して、受信した上記画像データのメモリ(VRAM50)への書込み、および該画像データの上記表示部への出力の少なくともいずれかを行うデータ処理部(データ処理部40)と、を備え、上記データ処理部は、自装置が上記画像データを受信したとき、該画像データを受信した第1垂直同期期間か、その次の第2垂直同期期間かのいずれかを所定の垂直同期期間とすると、上記所定の垂直同期期間において画像更新が行われる場合、上記画像データの書込みを行わず該画像データの出力を行い(スルー出力)、上記所定の垂直同期期間において画像更新が行われない場合、上記画像データの書込み(ライト)を行う。
1、4 表示制御装置
2、5 ホスト
3 LCD(表示部)
10 コマンド受信部(情報受信部)
20 画像受信部
30 処理判定部
40 データ処理部
50 VRAM(メモリ)
60 読出出力部
70 内部TG(タイミング決定部)
100 更新要求取得部
110、111 更新判定部
120、121 コマンド生成部
130、131 画像送信部
140 更新情報バッファ
Claims (11)
- ホストから受信した1フレーム分の画像データを表示部に出力する表示制御装置であって、
上記表示部の画像更新を行うか否かを示す更新情報を上記ホストから受信する情報受信部と、
上記更新情報に対応して、受信した上記画像データのメモリへの書込み、および該画像データの上記表示部への出力の少なくともいずれかを行うデータ処理部と、を備え、
上記データ処理部は、自装置が上記画像データを受信したとき、該画像データを受信した第1垂直同期期間か、その次の第2垂直同期期間かのいずれかを所定の垂直同期期間とすると、
上記所定の垂直同期期間において画像更新が行われる場合、上記画像データの書込みを行わず該画像データの出力を行い、
上記所定の垂直同期期間において画像更新が行われない場合、上記画像データの書込みを行うことを特徴とする表示制御装置。 - 上記所定の垂直同期期間は上記第1垂直同期期間であることを特徴とする、請求項1に記載の表示制御装置。
- 上記データ処理部が上記表示部に上記画像データを出力してから所定の期間、上記画像更新が行われない場合、上記ホストから再送された該画像データを上記メモリに書込むことを特徴とする、請求項2に記載の表示制御装置。
- 上記所定の垂直同期期間は上記第2垂直同期期間であることを特徴とする、請求項1に記載の表示制御装置。
- 上記データ処理部は、上記第2垂直同期期間において上記画像更新が行われず、かつ上記第1垂直同期期間において上記画像更新が行われる場合、上記画像データの上記メモリへの書込みと、該画像データの上記表示部への出力とを行うことを特徴とする、請求項4に記載の表示制御装置。
- 上記データ処理部が上記表示部に上記画像データを出力してから上記画像更新が行われずに所定の時間が経過した場合に、上記メモリから上記画像データを読み出して上記表示部に出力する読出出力部を備えることを特徴とする、請求項1から5のいずれか1項に記載の表示制御装置。
- 上記データ処理部は、上記第1垂直同期期間の垂直フロントポーチ期間内に上記ホストから上記画像データを受信開始するとともに、当該画像データの表示部への出力を開始することを特徴とする、請求項6に記載の表示制御装置。
- 上記データ処理部は、上記第1垂直同期期間の垂直フロントポーチ期間より前に上記更新情報を受信することを特徴とする、請求項7に記載の表示制御装置。
- 上記表示部への上記画像データの出力タイミングを決定するタイミング決定部であって、上記第1垂直同期期間において画像更新が行われる場合、自装置が上記画像データを受信するまで上記表示部の駆動タイミングを遅延させるタイミング決定部を備えることを特徴とする、請求項7または8に記載の表示制御装置。
- 請求項1~9のいずれか1項に記載の表示制御装置を含む表示装置。
- ホストから受信した1フレーム分の画像データを表示部に出力する表示制御装置の表示制御方法であって、
上記表示部の画像更新を行うか否かを示す更新情報を上記ホストから受信する情報受信ステップと、
上記情報受信ステップにて受信した上記更新情報に対応して、受信した上記画像データのメモリへの書込み、および該画像データの上記表示部への出力の少なくともいずれかを行うデータ処理ステップと、を含み、
自装置が上記画像データを受信したとき、該画像データを受信した第1垂直同期期間か、その次の第2垂直同期期間かのいずれかを所定の垂直同期期間とすると、
上記データ処理ステップにおいて、上記所定の垂直同期期間において画像更新が行われる場合、上記画像データの書込みを行わず該画像データの出力を行い、
上記所定の垂直同期期間において画像更新が行われない場合、上記画像データの書込みを行うことを特徴とする表示制御方法。
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