Patent Grant
10607576
The present invention relates to a display device.
There exists a display device which reads out image data written in a frame memory and transfers the image data thus read out to a display panel such as an LCD (Liquid Crystal Display). In a case where image data is transferred from a host processor (hereinafter referred to simply as “host”) to the display panel such as the LCD, the image data is typically first stored temporarily in the frame memory of an LCDC (LCD Controller), and is then outputted to the display panel. Accordingly, while the image is not changed, transfer of image data from the host to the frame memory can be stopped, and display on the display panel can continue to be carried out with use of the image data which is already stored in the frame memory.
However, in a case where a process of writing image data into the memory and a process of reading out the image data from the memory are carried out substantially simultaneously in the display device having the above-described arrangement, one of the writing process and the reading process may overtake the other while the other is still being carried out, due to, for example, a difference in speed between the writing process and the reading process. In this case, image data that is read before the overtaking is different from image data that is read after the overtaking. As a result, image data outputted to the display panel may contain both a portion of the image which was read before the overtaking and a portion of the image which was read after the overtaking.
Patent Literature 1 discloses a frame rate changing device which temporarily stops writing in a case where the frame rate changing device determines that overtaking between writing and reading will occur.
[Patent Literature 1]
Japanese Patent Application Publication, Tokukai, No. 2005-124167 A (Publication Date: May 12, 2005)
However, the technology disclosed in Patent Literature 1 involves stopping writing image data into a frame memory but does not involve stopping transferring image data from a host to a memory control section. Accordingly, image data which is supposed to be displayed may not be displayed, so that seamless display of moving images may be prevented.
The present invention is accomplished in view of the foregoing problem. An object of the present invention is to provide a display device which promptly displays image data to be displayed and also seamlessly displays consecutive image data.
In order to attain the object, a display device in accordance with one aspect of the present invention is a display device including: a host configured to transfer image data to a display control section; and the display control section configured to control display of the image data, the host including: an image generation section configured to generate the image data; and an image transferring section configured to transfer, to the display control section, the image data generated by the image generation section, a single frame period with respect to a predetermined refresh rate being a single unit period, the image generation section being configured to, upon completion of generation of the image data, start generating, in a case where the generation of the image data for a single frame was completed within less than the single unit period, image data for a subsequent frame after the single unit period has passed since the generation of the image data for the single frame was started, and start generating, in a case where the generation of the image data for a single frame was not completed within less than the single unit period, image data for a subsequent frame any time after the completion of the generation of the image data for the single frame.
In order to attain the object, a method, in accordance with one aspect of the present invention, for controlling a display device is a method for controlling a display device, the display device including: a host configured to transfer image data to a display control section; and the display control section configured to control display of the image causing the host to generate the image data; and an image transfer step of causing the host to transfer, to the display control section, the image data generated through the image generation step, a single frame period with respect to a predetermined refresh rate being a single unit period, the image generation step being configured to, upon completion of generation of the image data, start generating, in a case where the generation of the image data for a single frame was completed within less than the single unit period, image data for a subsequent frame after the single unit period has passed since the generation of the image data for the single frame was started, and start generating, in a case where the generation of the image data for a single frame was not completed within less than the single unit period, image data for a subsequent frame any time after the completion of the generation of the image data for the single frame.
The one aspects of the present invention allow achieving prompt display of image data to be displayed as well as seamless display of consecutive image data.
[Embodiment 1]
The following description will discuss Embodiment 1 of the present invention in detail with reference to
<Configuration of Display Device>
With reference to
The host 10 generates image data to be displayed next by the display device 1, and transfers the image data thus generated to the display control section 20. The host 10 includes an image generation section 11 and an image transferring section 12. Note that the host 10 generates and transfers image data at timing determined by the host 10 itself, not at timing indicated by the display control section 20.
The display control section 20 controls display of the display device 1, and includes a receiving section 21, writing section 22, a storage section 23, a reading section 24, a sync signal generation section 25, and an update control section 26. Each section of the display control section 20 may be realized, for example, by a circuit. In a case where image data is transferred from the host 10 to the display control section 20, the display control section 20 first temporarily stores the image data in the storage section 23. Further, the display control section 20 generates a vertical sync signal (Vsync), which is a signal for driving the display section 30, and supplies, to the display section 30, the vertical sinc signal and image data read out from the storage section 23. In this manner, the display control section 20 controls display of the display section 30. Further, the display control section 20 carries out a display refresh on the display section 30 at appropriate timing. Note that the display device 1 differs from display devices of conventional technologies in that an interval at which the vertical sinc signal is generated is not limited to an integral multiple of a single frame period with respect to a predetermined refresh rate (e.g., 120 Hz, 60 Hz, or the like), and can change appropriately. For example, in a case where the display control section 20 and the display section 30 are capable of operating at a maximum refresh rate of 120 Hz, a single frame period is 1/120 second.
The display section 30 displays image data under control of the display control section 20. The display section 30 includes a display screen having a plurality of pixels. The display section 30, for example, is constituted by an oxide semiconductor liquid crystal display panel which serves as an active matrix liquid crystal display panel. The oxide semiconductor liquid crystal display panel is a liquid crystal display panel in which an oxide semiconductor-TFT (thin film transistor) is used for a switching element which is provided so as to correspond to every predetermined number (wherein the number is 1 or greater) of the plurality of pixels which are arranged two-dimensionally. The oxide semiconductor-TFT is a TFT in which an oxide semiconductor is used in a semiconductor layer. Examples of the oxide semiconductor include an oxide semiconductor (InGaZnO-based oxide semiconductor) in which an oxide of indium, gallium, and zinc is used. According to the oxide semiconductor-TFT, an amount of electric current flowing in an on state is large, and an amount of leak electric current in an off state is small. Accordingly, the use of the oxide semiconductor-TFT for the switching element enables an increase in pixel aperture ratio and a reduction in refresh rate of image display to approximately 1 Hz.
The image generation section 11 generates image data to be displayed by the display device 1. Single image data represents an image for a single frame. The image generation section 11 outputs an image which has been generated to the image transferring section 12. When the image transferring section 12 starts transferring image data for a frame, the image generation section 11 starts generating image data for a subsequent frame. The image transferring section 12 transfers image data which has been generated to the display control section 20. When generation of image data is completed, the image transferring section 12 starts transferring the image data.
The receiving section 21 receives image data from the image transferring section 12. The receiving section 21 outputs the image data thus received to the writing section 22. The writing section 22 writes image data into the storage section 23. The storage section 23 stores therein image data transferred from the host 10. Note that the storage section 23 is a frame memory which has a region in which image data for a single frame is stored, and when the host 10 transfers new image data, the data in the region is overwritten. The reading section 24 reads out image data from the storage section 23. The reading section 24 outputs image data to the update control section 26. When image data starts to be transferred from the host 10, the sync signal generation section 25 generates a control signal, which is a signal for driving the display section 30, and supplies the control signal to the update control section 26. The control signal includes, for example, a vertical sinc signal (Vsync), a horizontal sync signal, a clock signal, and the like. On the basis of the vertical sinc signal, the update control section 26 instructs the reading section 24 as to timing at which image data is to be read out. The update control section 26 supplies image data, which has been read out from the storage section 23, and the control signal to the display section 30.
<General Description of Operation of Display Device>
With reference to
(a) of
(b) of
With reference to
(Display Refresh)
As used herein, “display refresh” means an operation in which image data which is currently displayed on the display section 30 is updated by being overwritten with image data identical to that image data, in order to prevent deterioration of display of the display section 30. That is, display refresh does not involve a change of an image. For example, in a case where (i) the display control section 20 has not received any image data to be newly displayed from the host 10 and (ii) no display refresh was carried out while a single frame period with respect to a minimum refresh rate of the display section 30 passed, the display control section 20 can carry out a display refresh.
<Flow of Processes Carried Out by Host>
In a case where the image generation section 11 determines that it is not necessary to generate new image data (NO at S1), the image generation section 11 ends the process without generating image data. Note that in a case where there is no need to change the image, the host 10 neither generates nor transfers new image data.
In a case where the image generation section 11 determines that it is necessary to generate new image data (YES at S1), the image generation section 11 determines whether or not transfer, to the display control section 20, of image data which was generated immediately previously has been started (S2). Note that the image generation section 11 determines YES at S2 also in a case where the transfer of the image data which was generated immediately previously has been completed.
In a case where the transfer of the image data which was generated immediately previously has not been started (NO at S2), the image generation section 11 waits until the transfer of the image data which was generated immediately previously is started.
In a case where the transfer of the image data which was generated immediately previously has been started (YES at S2), the image generation section 11 starts generating new image data in accordance with a start of the transfer of the image data which was generated immediately previously (S3; image generation step). The image generation section 11 outputs the new image data thus generated to the image transferring section 12. The image transferring section 12 determines whether or not (i) the transfer of the image data which was generated immediately previously has been completed and not less than a single unit period has passed since the start of the transfer of the image data which was generated immediately previously (S4). Note here that a single unit period means a single frame period with respect to a predetermined refresh rate of the display section 30.
In a case where the transfer of the image data which was generated immediately previously has not been completed or in a case where a single unit period has not passed since the start of the transfer (NO at S4), the image transferring section 12 waits without starting transferring the new image data.
In a case where (i) the transfer of the image data which was generated immediately previously has been completed and (ii) not less than a single unit period has passed since the start of the transfer of the image data generated last (YES at S4), the image transferring section 12 starts transferring the new image data to the display control section 20 any time (immediately) (S5; image transfer step). The host 10 repeats this series of processes.
As described above, while there is no delay in generation of an image, the image transferring section 12 starts transferring new image data to the display control section 20 after at least a single frame period has passed since a start of immediately previous transfer of image data. This allows the display control section 20 and the display section 30 to perform image display at a predetermined refresh rate. Meanwhile, in a case where a delay occurs in generation of image data due to, for example, excessive load on the host 10, transfer of the image data is also delayed. Even in this case, the image generation section 11 immediately generates subsequent image data without being restricted to the timing of an integral multiple of a single frame period, so that the image transferring section 12 can transfer the subsequent image data.
In a conventional display device, generation or transfer of new image data is started after an interval of an integral multiple of a single frame period has passed since a start of generation or transfer of previous image data. This is because the display control section 20 carries out image generation and image transfer in accordance with the timing of a vertical sinc signal which is generated at regular intervals.
By contrast, the display device 1 of Embodiment 1 is configured such that once generation or transfer of previous image data is completed, generation or transfer of new image data can be started at timing when a given length of period (e.g., a period equal to a non-integral multiple of a single frame period) which is not less than a single frame period has passed since a start of the generation or transfer of the previous image data. Accordingly, even in a case where the generation of the previous image data is delayed, the host 10 can immediately generate new image data and transfer the new image data to the display control section 20. This allows the display device 1 to display consecutive image data seamlessly.
Note that when generation of new image data is completed, the image transferring section 12 can immediately start transfer of the new image data, provided that the previous image data is not still being transferred.
<Flow of Processes Carried Out by Display Control Section>
In a case where the receiving section 21 determines that the transfer has not been started (NO at S11), the process proceeds to S13.
In a case where the receiving section 21 determines that the transfer has been started (YES at S11), the receiving section 21 starts receiving the image data and notifies the sync signal generation section 25 that the receiving section 21 has started receiving the image data. The receiving section 21 writes the image data into the storage section 23 via the writing section 22 (S12). The process proceeds to S13.
At S13, the update control section 26 determines whether or not it is necessary to conduct a display refresh which does not involve changing an image. Specifically, the update control section 26 determines whether or not (i) no image data is being transferred from the host 10 and (ii) a predetermined period (e.g., 1 second) has passed since the image data was written into the display section 30. The predetermined period is a period during which display of the display section 30 can be maintained without performing a refresh. In other words, the predetermined period is a single frame period (e.g., 1 second) with respect to a minimum refresh rate (e.g., 1 Hz) of the display section 30. Further, the update control section 26 determines whether or not the receiving section 21 is receiving image data from the host 10 S14, S15).
In a case where the update control section 26 determines that (i) a display refresh is necessary (YES at S13) and (ii) the receiving section 21 is not receiving image data (NO at S14), the sync signal generation section 25 generates a vertical sinc signal. Further, the update control section 26 reads, via the reading section 24, image data which is stored in the storage section 23. The update control section 26 supplies the vertical sinc signal and the image data to the display section 30 so that display of the display section 30 is refreshed (S17).
In a case where the update control section 26 determines that (i) no display refresh is necessary (NO at S13) and (ii) the receiving section 21 is not receiving image data (NO at S15), the update control section 26 ends the process.
In a case where the update control section 26 determines that the receiving section 21 is receiving image data (YES at S14 or YES at S15), the update control section 26 determines whether or not less than a predetermined proportion e.g., not less than 1/10) of a total amount of the image data which is being received from the host 10 has been received (S16).
In a case where the update control section 26 determines that less than the predetermined proportion of the total amount of the image data has been received (NO at S16), the update control section 26 waits until not less than the predetermined proportion of the total amount of the image data has been received.
In a case where the update control section 26 determines that not less than the predetermined proportion of the total amount of the image data has been received (YES at S16), the sync signal generation section 25 generates a vertical sinc signal. Further, the reading section 24 reads out image data which is stored in being written into) the storage section 23. The update control section 26 supplies the vertical sinc signal and the image data to the display section 30 so that the image data is written into the display section 30 (S17). In a case where not less than the predetermined proportion of the image data has been received (written), reading will not overtake writing after the reading section 24 starts reading image data from the storage section 23. The display control section 20 repeats this series of processes.
According to the above processes, in a case where the display control section 20 receives image data from the host 10, the display control section 20 can supply image data to the display section 30 immediately at timing with which no overtaking is expected to occur between writing and reading image data into and from the storage section 23. Further, while no image data is received, the display control section 20 can carry out a display refresh at appropriate timing with which no deterioration of display of the display section 30 occurs.
[Embodiment 2]
The following description will discuss Embodiment 2 of the present invention with reference to
[Configuration of Main Parts of Display Device]
In Embodiment 2, the display device 1 has the same configuration as that illustrated in
<Flow of Processes Carried Out by Host>
<Flow of Processes Carried Out by Display Control Section>
At S17, as with Embodiment 1, the update control section 26 reads out image data from the storage section 23 via the reading section 24, and supplies the image data to the display section 30. Note that the image data read out from the storage section 23 at this stage is (i) identical to image data which is currently displayed on the display section 30, in a case where S17 follows S31 and (ii) image data which has been newly received from the host 10, in a case where S17 follows S15. When the reading section 24 starts reading out the image data, the receiving section 21 turns the transfer timing signal Low (S32).
According to the above processes, the display control section 20 sets a transfer inhibit time period only in a case of carrying out display refresh, so that the display control section 20 can inhibit transfer of image data from the host 10. This allows preventing overtaking between a write operation and a read operation on the storage section 23.
[Embodiment 3]
[Configuration of Main Parts of Display Device]
The following description will discuss Embodiment 3 of the present invention with reference to
<Flow of Processes Carried Out by Display Control Section>
In
The update control section 26 determines whether or not a display refresh on the display section 30 is necessary (S13). In a case where the update control section 26 determines that the display refresh is necessary (YES at S13), the update control section 26 further determines whether or not the display control section 20 is receiving image data into the first frame memory (S41). In a case where the update control section 26 determines that the display control section 20 is not receiving image data (NO at S41), the process proceeds to S44. In a case where the display control section 20 is receiving image data into the first frame memory 121 (YES at S41), the update control section 26 further determines whether or not less than a predetermined proportion (e.g., not less than 1/10) of a total amount of the image data which is being received from the host 10 into the first frame memory 121 has been received (S42). In a case where the update control section 26 determines that not less than the predetermined proportion of the total amount of the image data has been received (YES at S42), the update control section 26 determines that reading will not overtake writing after reading of the image data is started. Thus, the process proceeds to S44. In a case where the update control section 26 determines that less than the predetermined proportion of the total amount of the image data has been received (NO at S42), the update control section 26 determines that reading may overtake writing after the image data in the first frame memory 121 starts being read out. Thus, the update control section 26 reads out the image data from the second frame memory 122 via the reading section 24 so as to cause the display section 30 to display the image data (S45), and ends the process.
Further, in a case of NO at S13, that is, in a case where the update control section 26 determines that no display refresh is necessary, the update control section 26 further determines whether or not the display control section 20 is receiving image data from the host 10 into the first frame memory 121 (S43). In a case where the update control section 26 determines that the display control section 20 is receiving image data (YES at S43), the process proceeds to S42. In a case where the update control section 26 determines that the display control section 20 is not receiving image data (NO at S43), the series of processes is ended.
In a case of NO at S41 or YES at S42, the update control section 26 determines that a certain amount of image data among the latest image data, at which amount no overtaking occurs between input and output, has been written into the first frame memory 121. Accordingly, the update control section 26 reads out the image data from the first frame memory 121 so as to cause the display section 30 to display the image data (S44), and ends the process.
According to the above processes, in a case where the display control section 20 receives image data from the host 10, the display control section 20 can read out image data and cause the image data to be displayed immediately at timing with which no overtaking is expected to occur between input and output of image data. Further, while no image data is received, the display control section 20 can update displayed data at appropriate timing with which no deterioration of display of the display section 30 occurs.
[Embodiment 4]
[Configuration of Main Parts of Display Device]
The following description will discuss Embodiment 4 of the present invention with reference to
In Embodiment 4, the display device 1 has the same configuration as that illustrated in
<Flow of Processes Carried Out by Host>
According to the above processes, the host 10 can switch the operation mode of the display control section 20 on the basis of whether or not there is an image to be outputted next for display (whether or not a change of the image is to be made).
<Flow of Processes Carried Out by Display Control Section>
At S61, in a case where it is determined that the current operation mode is not the second mode (NO at S61), that is, in a case where it is determined that the current operation mode is the first mode, the process proceeds to S11. Note that the process at S11 is the same as that in Embodiment 1. Then, in a case of YES at S11, a receiving section 21 starts receiving image data, and notifies a sync signal generation section 25 that reception of the image data has been started. Upon reception of the notification, the sync signal generation section 25 generates a vertical sinc signal. Further, the receiving section 21 outputs the image data thus received to both of the update control section 26 and a writing section 22. The update control section 26 supplies, to the display section 30, the image data received from the receiving section 21 and the vertical sinc signal (S64). In this manner, the update control section 26 supplies image data to the display section 30 without intermediation of the storage section 23. Further, the writing section 22 receives image data from the receiving section 21 and writes the image data into the storage section 23. The image data written into the storage section 23 is used for a display refresh when the operation mode of the display control section 20 is the second mode. Thus, the display control section 20 ends the process. In a case of NO at S11, the series of processes is ended.
According to the above processes, the display control section 20 can (i) switch the operation mode at appropriate timing in accordance with an instruction from the host 10, obtain one of image data which is being received and image data which has been stored in the storage section 23, in accordance with the operation mode thus switched, and (iii) cause the image data thus obtained to be displayed on the display section 30. Note that also in the display device 1 of Embodiment 4, once generation or transfer of previous image is completed, generation or transfer of new image data can be started at timing when a given length of period which is not less than a single frame period has passed since a start of the generation or transfer of the previous image data.
[Embodiment 5]
[Configuration of Main Parts of Display Device]
The following description will discuss Embodiment 5 of the present invention with reference to
In Embodiment 5, the display device 1 has the same configuration as that of Embodiment 1, but functions of an update control section 26 are partially different from those of Embodiment 1. When transfer of image data from the host 10 is started during a display refresh, the update control section 26 suspends the display refresh which is being carried out. When not less than a predetermined proportion (e.g., not less than 1/10) of a total amount of the image data which is being received by the display control section 20 has been received, the update control section 26 starts reading out the image data from a storage section 23 via a reading section 24. Processes carried out by the host 10 are the same as those of Embodiments 1 and 3 (
<Flow of Processes Carried Out by Display Control Section>
In a case where the update control section 26 determines that no display refresh is necessary (NO at S13 the process proceeds to S15. Note that S15 is the same as that of Embodiment 1. In a case where the update control section 26 determines that the receiving section 21 is receiving image data (YES at S15), and when not less than a predetermined proportion (e.g., not less than 1/10) of a total amount of the image data which is being received by the display control section 20 has been received, the update control section 26 starts reading out the image data from the storage section 23 via the reading section 24 (S74). In a case where the update control section 26 determines that the receiving section 21 is not receiving image data (NO at S1 the series of processes is ended.
According to the above processes, the display control section 20 can display transferred image data promptly even during a display refresh.
[Software Implementation Example]
Control blocks of the display device 1 (particularly, the image generation section 11 and the image transferring section 12) may be realized by a logic circuit (hardware) provided in an integrated circuit (IC chip) or the like or may be realized by software as executed by a CPU (Central Processing Unit).
In the latter case, the display device 1 includes: a CPU that executes instructions of a program that is software realizing the foregoing functions; ROM (Read Only Memory) or a storage device (each referred to as “storage medium”) storing the program and various kinds of data in such a form that they are readable by a computer (or a CPU); and RAM (Random Access Memory) that develops the program in executable form. The object of the present invention can be achieved by a computer (or a CPU) reading and executing the program stored in the storage medium. The storage medium may be “a non-transitory tangible medium” such as a tape, a disk, a card, a semiconductor memory, and a programmable logic circuit. Further, the program may be made available to the computer via any transmission medium (such as a communication network and a broadcast wave) which enables transmission of the program. Note that the present invention can also be implemented by the program in the form of a computer data signal embedded in a carrier wave which is embodied by electronic transmission.
Note that although each of Embodiments 1 through 5 discussed an example case in which the host and the display control section are realized as individual configurations, the host and the display control section may instead be realized as a single configuration. That is, the host may be configured to carry out operations of the display control section.
[Recap]
A display device (1/100) in accordance with Aspect 1 of the present invention is a display device (1/100) including: a host (10) configured to transfer image data to a display control section (20); and the display control section (20) configured to control display of the image data, the host (10) including: an image generation section (11) configured to generate the image data; and an image transferring section (12) configured to transfer, to the display control section (20), the image data generated by the image generation section (11), a single frame period with respect to a predetermined refresh rate being a single unit period, the image generation section (11) being configured to, upon completion of generation of the image data, start generating, in a case where the generation of the image data for a single frame was completed within less than the single unit period, image data for a subsequent frame after the single unit period has passed since the generation of the image data for the single frame was started, and start generating, in a case where the generation of the image data for a single frame was not completed within less than the single unit period, image data for a subsequent frame any time after the completion of the generation of the image data for the single frame. According to the above configuration, in accordance with timing at which the host completes generating image data, timing for starting generation of image data for a subsequent frame is controlled. This allows the image generation section to generate subsequent image data without being restricted to timing of an integral multiple of a single frame period. Accordingly, even in a case where image generation is delayed, it is possible to reduce delay of display and also to display consecutive image data seamlessly.
In Aspect 2 the present invention, the display device in accordance with Aspect 1 is configured such that when the image generation section (11) completes the generation of the image data, the image transferring section (12) immediately starts transferring the image data to the display control section (20), in a case where no image data is being transferred. According to the above configuration, when the image generation section completes generation of image data for a subsequent frame, transfer of the image data is immediately started. This enables prompt display of image data to be displayed.
In Aspect 3 of the present invention, the display device (1/100) in accordance with Aspect 1 or 2 is configured such that: the display control section (20) includes a sync signal generation section (25) configured to generate a vertical sinc signal any t in accordance with timing at which the image data is received from the image transferring section (12); and the display control section (20) supplies the vertical sinc signal to a display section (30) which is configured to display an image. According to the above configuration, in accordance with timing at which image data is received, the display control section generates a vertical sinc signal and updates content displayed on the display section. Accordingly, the display control section can update displayed content immediately when new image data is received. This enables prompt display of image data to be displayed.
In Aspect 4 of the present invention, the display device (1/100) in accordance with any one of Aspects 1 through 3 is configured such that: the display control section (20) further includes: a receiving section (21) configured to receive the image data from the image transferring section (12); a storage section (23) configured to store therein the image data received; and an update control section (26) configured to read out the image data from the storage section (23) and supply the image data to a/the display section (30); and a speed at which the update control section (26) reads out the image data from the storage section (23) is higher than a speed at which the receiving section (21) writes the image data into the storage section (23). According to the above configuration, reading of image data from the storage section is prevented from being overtaken by writing of the image data into the storage section. Accordingly, the host can freely determine timing for transferring image data. This allows promptly displaying image data even in a case where generation of the image data is delayed.
In Aspect 5 of the present invention, the display device (1) in accordance with Aspect 4 is configured such that in a case where the display control section (20) is receiving the image data from the image transferring section (12), the update control section (26) starts reading out the image data from the storage section (23) when not less than a predetermined proportion of a total amount of the image data has been received. According to the above configuration, the display control section does not start updating displayed content until reception of image data proceeds to a certain extent. This prevents reading of image data from overtaking reception of the image data.
In Aspect 6 of the present invention, the display device (1) in accordance with Aspect 4 is configured such that in a case where the display control section (20) carries out a display refresh on the display section (30) without reception of new image data by the receiving section (21), the receiving section (21) inhibits, for a predetermined period until the update control section (26) starts reading out the image data from the storage section (23), transfer of new image data from the host (10). The above configuration allows preventing a read operation on the storage section from overtaking a write operation on the storage section.
In Aspect 7 of the present invention, the display device (100) in accordance with Aspect 4 is configured such that: the storage section (23) includes a first frame memory (121) and a second frame memory (122); the receiving section (21) stores, in the first frame memory or the second frame memory, the image data received from the host (10); and while the image data is being written into the first frame memory, the update control section (26) starts reading out the image data from the first frame memory in a case where not less than a predetermined proportion of a total amount of the image data has been written into the first frame memory, and starts reading out image data for a previous frame from the second frame memory in a case where less than the predetermined proportion of the total amount of the image data has been written into the first frame memory. According to the above configuration, in a case where a display refresh and reception of image data overlap with each other, whether to carry out a display refresh or display of the image data can be selected appropriately in accordance with an extent of progress of the reception. This allows seamlessly displaying consecutive image data.
In Aspect 8 of the present invention, the display device (1) in accordance with Aspect 4 is configured such that: in accordance with an instruction from the host (10), the update control section (26) operates between two operation modes of: a first mode in which the image data received from the host (10) is supplied to the display section (30) without intermediation of the storage section (23); and a second mode in which the image data stored in the storage section (23) is supplied to the display section (30); and the image transferring section (12) instructs the display control section (20) to switch an operation mode of the update control section (26) to the second mode in a case where transfer of the image data is unnecessary, and instructs the display control section (20) to switch the operation mode of the update control section (26) to the first ode in a case where transfer of the image data is necessary. According to the above configuration, delay caused by temporarily storing image data in the storage section first is reduced in a case of the first mode, and power consumption is reduced due to the lack of data transfer to and from the host in a case of the second mode. Thus, in a case where image data has been received, the display control section immediately causes the image data to be displayed without intermediation of the storage section, and in a case where no image data has been received, the display control section carries out a refresh with use of image data in the storage section. This allows new image data, if any, to be displayed immediately, allows consecutive image data to be displayed seamlessly, and further allows a reduction in power consumption during absence of new image data.
In Aspect 9 of the present invention, the display device (1) in accordance with Aspect 4 is configured such that in a case where the receiving section (21) starts receiving new image data while the update control section (26) is reading out the image data from the storage section (23), the update control section (26) suspends reading of the image data from the storage section (23). According to the above configuration, in a case where transfer of image data is started during a display refresh, the display refresh is suspended, and displayed content is updated with use of the image data which is being received. This allows promptly starting display of image data in a case where a display refresh and transfer of the image data overlap with each other.
A method, in accordance with Aspect 10 of the present invention, for controlling a display device (1/100) is a method for controlling a display device (1/100), the display device including: a host (10) configured to transfer image data to a display control section; and the display control section configured to control display of the image data, the method including: an image generation step (S3) of causing the host (10) to generate the image data; and an image transfer step (S5) of causing the host to transfer, to the display control section, the image data generated through the image generation step (S3), a single frame period with respect to a predetermined refresh rate being a single unit period, the image generation step (S3) being configured to, upon completion of generation of the image data, start generating, in a case where the generation of the image data for a single frame was completed within less than the single unit period, image data for a subsequent frame after the single unit period has passed since the generation of the image data for the single frame was started, and start generating, in a case where the generation of the image data for a single frame was not completed within less than the single unit period, image data for a subsequent frame any time after the completion of the generation of the image data for the single frame. The above method brings about effects similar to those of Aspect 1.
The display device in accordance with the aspects of the present invention may be realized by a computer. In this case, a program for controlling the display device which program realizes the display device with use of a computer by causing the computer to function as sections (software elements) of the display device, and a computer-readable storage medium in which the program is stored, are also encompassed in the present invention.
The present invention is not limited to the embodiments, but can be altered by a skilled person in the art within the scope of the claims. The present invention also encompasses, in its technical scope, any embodiment derived by combining technical means disclosed in differing embodiments. Further, it is possible to form a new technical feature by combining the technical means disclosed in the respective embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-074648 | Apr 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/012788 | 3/29/2017 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2017/170630 | 10/5/2017 | WO | A |
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| Number | Date | Country | |
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| 20190114997 A1 | Apr 2019 | US |
