JP2015139196A - display device and display system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device and display system capable of suppressing reduction in picture quality as much as possible, by suppressing determining that normal display on a display unit is impossible when it is possible.SOLUTION: A television device 1 comprises: a display unit 12; an HDMI terminal 15; and a CPU 11 configured so as to, when a state determined to be a state in which a synchronous signal of a video signal acquired through the HDMI terminal 15 is unstable has continued for a predetermined first period (for example, 20 seconds), transmit EDID (second image quality information) including information having the highest image quality of information composed of information having image quality lower than the highest image quality included in EDID (first image quality information) to a hard disk recorder 2 through the HDMI terminal 15 as well as perform control of acquiring a video signal on the basis of information having the highest image quality of EDID (second image quality information) received through the HDMI terminal 15.

Description

  The present invention relates to a display device and a display system, and more particularly to a display device and a display system including a display unit that displays a video signal based on image quality information.

  2. Description of the Related Art Conventionally, a display device and a display system that include a display unit that displays an image based on image quality information have been known (see, for example, Patent Document 1).

  Patent Document 1 discloses a content playback apparatus including a display unit that plays back content (video) acquired from a source device in accordance with set playback performance information (image quality information). In this content reproduction apparatus, when the synchronization signal in the video signal is detected and the period of the detected synchronization signal is constant (increase / decrease is smaller than a predetermined threshold), it is determined that normal display is possible, Otherwise, control is performed to determine that normal display is impossible. In addition, when it is determined that normal display is impossible, the content reproduction apparatus is configured to rewrite from image quality information reproduced with high image quality performance to image quality information reproduced with low image quality performance. Here, the synchronization signal of the video signal with low image quality performance has a longer period than the synchronization signal of the video signal with high image quality performance, and the period of the synchronization signal of the video signal does not easily become unstable. As a result, the content reproduction apparatus is configured to be able to suppress a state in which normal display due to an unstable period of the synchronization signal of the video signal cannot be performed on the display unit.

JP 2011-172146 A

  Here, the content reproduction apparatus of Patent Document 1 is configured to rewrite from image quality information to be reproduced with high image quality performance to image quality information to be reproduced with low image quality performance when the detection period of the synchronization signal is not constant. However, in general, it is considered that there are many cases where normal display is possible when the period in which the period of the synchronization signal is not constant is a short period. However, the content reproduction apparatus of Patent Document 1 determines that normal display is impossible even when normal display is possible in a short period in which the period of the synchronization signal is not constant, and is reproduced with high image quality performance. It is considered that there is a problem that the image quality information to be reproduced is rewritten from the image quality information to be reproduced with low image quality performance.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to suppress the determination that it is impossible when normal display can be performed on the display unit. Accordingly, it is an object of the present invention to provide a display device and a display system that can suppress a decrease in image quality as much as possible.

  In order to achieve the above object, a display device according to a first aspect of the present invention is configured to be connectable to a display unit for displaying video and an external transmission device via a predetermined cable, and the display unit can display the display unit. The first image quality information, which is information including the highest image quality, is transmitted to the external transmission device, the video signal based on the first image quality information is received from the external transmission device, and control for acquiring the received video signal is performed. And the control unit is included in the first image quality information when a state in which the synchronization signal of the video signal acquired via the connection unit is determined to be unstable continues for a predetermined first time. The second image quality information, which is information including the highest image quality that is lower than the highest image quality, is transmitted to the external transmission device via the connection unit, and the second image quality information received via the connection unit is the highest. Projection based on image quality It is configured to perform control to acquire the signal.

  In the display device according to the first aspect of the present invention, as described above, when the state in which the control unit determines that the synchronization signal of the acquired video signal is unstable continues for a predetermined first time, The second image quality information, which is information including the highest image quality that is lower than the highest image quality included in the image quality information, is transmitted to the external transmission device via the connection unit, and is received via the connection unit. By performing control to acquire a video signal based on the highest image quality of the image quality information, when the period of the synchronization signal is not constant and the normal display is possible with a short period (the synchronization signal is not If it is not stable), it is not determined to be unstable, so that it is possible to suppress determination as impossible when normal display (display of high-quality video) can be performed on the display unit. . As a result, it is possible to suppress the display of a low-quality image on the display unit in a state in which the synchronization signal is not unstable, so that a reduction in image quality can be suppressed as much as possible.

  In the display device according to the first aspect, preferably, the synchronization signal includes a clock signal, a horizontal synchronization signal, and a vertical synchronization signal, and the control unit includes the clock signal, the horizontal synchronization signal, and the vertical synchronization signal. When it is determined whether at least two of the synchronization signals are unstable, and the state in which any of the at least two synchronization signals is determined to be unstable continues for a predetermined first time In addition, the second image quality information, which is information including the highest image quality that is lower than the highest image quality included in the first image quality information, is controlled to be transmitted to the external transmission device via the connection unit. ing. If comprised in this way, compared with the case where it is determined whether it is unstable based only on one synchronous signal, it can be determined more correctly whether a synchronous signal is unstable. .

  In this case, preferably, when the number of clocks of the clock signal is different from the first predetermined number after the horizontal synchronization signal is acquired and until the next horizontal synchronization signal is acquired, Alternatively, the synchronization signal is unstable when the number of horizontal synchronization signals detected is different from the second predetermined number after the vertical synchronization signal is acquired and until the next vertical synchronization signal is acquired. Information including the highest image quality that is lower than the highest image quality included in the first image quality information when it is determined that the synchronization signal is unstable and the state in which it is determined to be unstable continues for a predetermined first time. Control is performed to transmit certain second image quality information to the external transmission device via the connection unit. With this configuration, it is possible to easily perform synchronization by comparing the number of clocks of the clock signal with the first predetermined number or comparing the number of detected horizontal synchronization signals with the second predetermined number. It can be determined whether the signal is unstable.

  In the display device according to the first aspect, preferably, the control unit transmits a video signal based on the second image quality information from the external transmission device to the connection unit, and displays a video other than the video from the external transmission device. When the first image quality information is controlled to be transmitted to the external transmission device and the synchronization signal is acquired via the connection unit and it is determined that the acquired synchronization signal is not unstable. The first image quality information is controlled to be transmitted to the external transmission device instead of the second image quality information. With this configuration, even when the synchronization signal is determined to be unstable in the past and the second image quality information is transmitted to the external transmission device, the synchronization signal changes from an unstable state to a non-unstable state. The first image quality information can be transmitted to the external transmission device, and an image based on the first image quality information can be acquired from the external transmission device. For example, when a user replaces a predetermined cable with a shorter cable or a higher quality cable, the synchronization signal may change from an unstable state to a non- unstable state. In such a case, by configuring as described above, it is possible to effectively suppress display of a low-quality image on the display unit in a state where the synchronization signal is not unstable.

  In this case, it is preferable that the control unit determines that the synchronization signal is not unstable when the synchronization signal acquired via the connection unit is in a stable state for a predetermined second time, and sets the second image quality information as the second image quality information. Instead, it is configured to perform control for transmitting the first image quality information to the external transmission device. With this configuration, it is possible to suppress the determination that the synchronization signal is not unstable at a time when the stable state of the synchronization signal is limited. Therefore, it is more accurately determined that the synchronization signal is not unstable. can do.

  In the display device including the control unit that determines that the synchronization signal is not unstable when the state in which the synchronization signal is stable continues for a predetermined second time, the second time is preferably shorter than the first time. Here, after the synchronization signal is detected, once the synchronization signal has been stable for a certain period of time, the synchronization signal remains after the point in time when the synchronization signal has been stabilized for a certain period of time. In many cases, a stable state continues. Therefore, in the present invention, by configuring the second time to be shorter than the first time, when the synchronization signal is not unstable, the determination can be performed in a shorter time.

  In the display device according to the first aspect described above, preferably, the control unit receives a video signal based on the second image quality information from the external transmission device, and the synchronization signal is not continuously received for a predetermined first time. When it is determined that the information is stable, control is performed to transmit information including the highest image quality, which is lower than the highest image quality included in the second image quality information, to the external transmission device. With this configuration, the image quality of the image displayed on the display unit can be lowered step by step, so that the image with the highest image quality performance among the displayable image quality performances can be displayed on the display unit.

  In this case, preferably, the first image quality information indicates that the first resolution information indicates that the first resolution exceeds the resolution in which the number of pixels in the horizontal direction is 1920 and the number of pixels in the vertical direction is 1080. And deep color information indicating that the deep color function is supported, and the second image quality information corresponds to the first non-support information indicating that the first resolution is not supported and deep color. And the second resolution information corresponding to a plurality of second resolutions lower than the first resolution, and the control unit makes the synchronization signal unstable for a predetermined first time. If it is determined that the second image quality information including the first non-corresponding information is transmitted to the external transmission device, and the second image quality information including the first non-corresponding information is transmitted, the synchronization signal is It is unstable for a predetermined first time. If it is determined that the second image quality information including the second non-corresponding information is transmitted to the external transmission device, and the second image quality information including the second non-corresponding information is transmitted, the synchronization signal is predetermined. If it is determined that it is unstable continuously for the first time, the information of the highest resolution that is sequentially lowered from the higher one of the plurality of resolutions corresponding to the second resolution information to the lower one is included for each determination. The second image quality information is controlled to be transmitted to the external transmission device. Here, in general, a change from a state corresponding to the first resolution to a state not compatible, a change from a state corresponding to the deep color function to a state not compatible, and a change to lower the second resolution to the lower one. Therefore, it is difficult to visually recognize the deterioration of the image quality of the video displayed on the display unit. Therefore, in the present invention, the control unit is controlled so as to reduce the image quality of the video in the order in which the degradation of the image quality of the video displayed on the display unit is not easily recognized, so that the user feels the video image quality is degraded. This can be suppressed as much as possible.

  In the display device according to the first aspect described above, preferably, the control unit switches to the on state immediately before the power source of the display device body is turned off when the power source of the display device body is switched from the off state to the on state. The first image quality information or the second image quality information transmitted to the external transmission device is controlled to be transmitted to the external transmission device. If comprised in this way, when switching the power supply of a display apparatus main body from an OFF state to an ON state, since a control part does not need to determine again whether a synchronizing signal is unstable, it is unnecessary. Since it is not necessary to perform control, the burden on the control unit can be reduced.

  In the display device according to the first aspect, preferably, the predetermined cable can transmit the video signal, the first image quality information, and the second image quality information based on the HDMI (High-Definition Multimedia Interface; registered trademark) standard. HDMI cable. According to this configuration, in the HDMI standard, EDID (Extended Display Identification Data) can be transmitted via the standardized DDC (Display Data Channel; registered trademark). By configuring the two image quality information as EDID, it is possible to easily transmit the first image quality information and the second image quality information to the external transmission device.

  The display system according to the second aspect of the present invention acquires first image quality information, which is information including the highest image quality that can be displayed on the display unit of the display device, from the display device via a predetermined cable. A transmission device that transmits a video signal based on one image quality information to a display device, a display unit that displays an image, and a transmission device are configured to be connectable to each other via a predetermined cable. A display device including a connection unit that transmits the video signal based on the first image quality information from the transmission device and a display device-side control unit that performs control to acquire the received video signal. The apparatus-side control unit is lower than the highest image quality included in the first image quality information when the state in which the synchronization signal of the video signal acquired via the connection unit is determined to be unstable continues for a predetermined first time. Highest of image quality Control is performed to transmit the second image quality information, which is information including image quality, to the transmission device via the connection unit and to acquire a video signal based on the highest image quality of the second image quality information received via the connection unit. Configured to do.

  In the display system according to the second aspect of the present invention, as described above, when the display device-side control unit determines that the synchronization signal of the acquired video signal is unstable for a predetermined first time. The second image quality information, which is information including the highest image quality that is lower than the highest image quality included in the first image quality information, is transmitted to the transmission device via the connection unit and received via the connection unit. By configuring the control so as to acquire a video signal based on the highest image quality of the second image quality information, it is not possible when normal display is possible with a short period in which the period of the synchronization signal is not constant. Since it is not determined to be stable, it is possible to suppress determination as impossible when normal display can be performed on the display unit. As a result, since it is possible to suppress the display of a low-quality image on the display unit in a state where the synchronization signal is not unstable, it is possible to suppress deterioration in image quality as much as possible.

  According to the present invention, as described above, it is possible to suppress degradation of image quality as much as possible by suppressing the determination that it is impossible when normal display can be performed on the display unit.

1 is a block diagram illustrating an overall configuration of a display system according to a first embodiment of the present invention. It is a figure of the notification display screen of the cable abnormality by 1st Embodiment of this invention. It is a figure for demonstrating the method to determine whether the synchronizing signal (TMDS clock signal and H Sync signal) by 1st Embodiment of this invention is unstable. It is a figure for demonstrating the method to determine whether the synchronizing signal (H Sync signal and V Sync signal) by 1st Embodiment of this invention is unstable. It is a flowchart for demonstrating abnormality determination of a synchronizing signal and EDID transmission / reception control processing of the display system by 1st Embodiment of this invention. It is a flowchart for demonstrating the EDID change control process of the display system by 1st Embodiment of this invention. It is a flowchart for demonstrating the abnormality determination of the synchronizing signal of the display system by 2nd Embodiment of this invention, and EDID transmission / reception change control processing. It is a flowchart for demonstrating the EDID change control process of the display system by 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
With reference to FIG. 1, the structure of the display system 100 by 1st Embodiment of this invention is demonstrated.

  As shown in FIG. 1, the display system 100 according to the first embodiment includes a television device 1, a hard disk recorder 2, and an HDMI cable 3 that connects the television device 1 and the hard disk recorder 2. The television device 1 is an example of the “display device” in the present invention. The hard disk recorder 2 is an example of the “external transmission device” and “transmission device” in the present invention. The HDMI cable 3 is an example of the “predetermined cable” in the present invention.

  The television apparatus 1 includes a CPU (Central Processing Unit) 11, a display unit 12, a broadcast reception unit 13, a broadcast signal processing unit 14, an HDMI terminal 15, a signal detection unit 16, a memory 17, An OSD (On Screen Display) unit 18, a power supply unit 19, an operation unit 20, and an internal bus 20a are included. The CPU 11 is an example of the “control unit” in the present invention. The HDMI terminal 15 is an example of the “connection unit” in the present invention.

  Further, the hard disk recorder 2 includes a CPU 21, an HDMI terminal 22, and a hard disk drive 23.

  As shown in FIG. 1, the broadcast receiving unit 13 of the television apparatus 1 has a receiving antenna 13a and a receiving tuner (not shown), and the receiving antenna 13a is a television distributed from each broadcaster. It is configured to receive broadcast waves. The reception tuner is configured to select a predetermined transmission channel and receive a television broadcast wave for each broadcaster. The broadcast signal processing unit 14 includes a demodulation circuit, a decoding unit, and the like. The broadcast signal processing unit 14 performs error correction of the television broadcast wave received by the broadcast reception unit 13 by the demodulation circuit and demodulates the TS (Transport Stream) signal. It is configured. The TS signal is configured to be decoded (decoded) by the decoding unit into an image signal, and the decoded image signal is output and displayed on the display unit 12 including a liquid crystal panel or the like. .

  As shown in FIG. 1, the OSD unit 18 is configured to output image data such as a cable abnormality notification display screen (see FIG. 2) described later to the display unit 12 based on a command from the CPU 11. Yes.

  As shown in FIG. 1, the memory 17 includes a volatile storage unit that temporarily stores data accompanying the processing operation of the CPU 11, an image to be displayed on the display unit 12, and a non-volatile storage that stores EDID. And a sex storage unit. The operation unit 20 is configured to accept an operation signal transmitted from an external remote controller (not shown) based on a user operation. The power supply unit 19 is configured to supply power to the entire television apparatus 1. In addition, the internal bus 20a is configured such that each component in the television device 1 can transmit signals to each other.

  The EDID includes information on the resolution corresponding to the resolution 2160p in which the number of pixels in the horizontal direction is 3840 and the number of pixels in the vertical direction is 2160 as the highest image quality that can be displayed by the display unit 12 (for example, 2160p, 1080p, 1080i, 720p, 480p constitutes EDID). Further, the EDID of the television apparatus 1 is configured so that the CPU 11 can change the highest image quality from the resolution 2160p to the lower resolution 1080p (in this case, the EDID is composed of 1080p, 1080i, 720p, and 480p). It is configured to be changeable to resolution information which is

  Here, in the first embodiment, as illustrated in FIG. 1, the HDMI terminal 15 includes a terminal based on the HDMI standard. Specifically, the HDMI terminal 15 includes a TMDS (Transition Minimized Differential Signaling) clock terminal, a TMDS data terminal, a DDC terminal (SCL (Serial Clock Line) and SDA (Serial Data Line)), and a hot plug. Including a detection terminal. The TMDS clock terminal is configured to receive the TMDS clock signal transmitted from the hard disk recorder 2 via the HDMI cable 3. Further, the TMDS data terminal is configured to receive a signal including a video / audio signal, an H Sync signal, and a V Sync signal transmitted from the hard disk recorder 2 via the HDMI cable 3. The DDC terminal is configured to be able to transmit and receive EDID or HDCP (High-Bandwidth Digital Content Protection System) authentication signals. The TMDS clock signal is an example of the “synchronization signal” and “clock signal” in the present invention. The H Sync signal is an example of the “synchronization signal” and “horizontal synchronization signal” in the present invention. The V Sync signal is an example of the “synchronization signal” and “vertical synchronization signal” in the present invention. The EDID is an example of “first image quality information” and “second image quality information” in the present invention.

  As shown in FIG. 1, the CPU 21 of the hard disk recorder 2 is configured to acquire the EDID transmitted from the television apparatus 1 via the HDMI cable 3 and the HDMI terminal 22. Specifically, when the voltage of the hot plug detection terminal of the HDMI terminal 22 is detected and the detected voltage changes from the Low level to the High level, the CPU 21 of the hard disk recorder 2 receives the DDC signal from the television device 1. The EDID is read and acquired through the terminal. The hard disk drive 23 is configured to record video and audio, and is configured to be able to read out stored video and audio based on a command from the CPU 21. Then, the CPU 21 of the hard disk recorder 2 has a video signal with image quality performance based on the acquired EDID (for example, a video signal that can be displayed at a resolution of 1080p when resolution information corresponding to the resolution of 1080p is included). In this case, the reading control from the hard disk drive 23 is performed. Then, the CPU 21 transmits a signal including a video signal based on the acquired EDID, a TMDS clock signal, an H Sync signal, and a V Sync signal to the television apparatus 1 via the HDMI terminal 22. It is configured.

  As shown in FIG. 1, the CPU 11 of the television apparatus 1 receives the video signal transmitted from the hard disk recorder 2 via the HDMI terminal 15 and displays the video corresponding to the video signal on the display unit 12. It is configured to perform control.

  As shown in FIG. 1, the signal detection unit 16 of the television apparatus 1 is configured to be able to detect a synchronization signal (TMDS clock signal, H Sync signal, V Sync signal) transmitted from the hard disk recorder 2. . Then, the CPU 11 transmits from the hard disk recorder 2 by determining whether the TMDS clock signal, the H Sync signal, and the V Sync signal detected by the signal detection unit 16 are unstable by a determination method described later. It is configured to determine whether or not the received video signal is abnormal.

  Here, in the first embodiment, the CPU 11 of the television apparatus 1 determines whether or not the synchronization signal of the video signal acquired via the HDMI terminal 15 is unstable, as described below. It is comprised so that it may determine by. Further, the CPU 11 is configured to determine that the synchronization signal is stable when the state that is not determined to be unstable by all the determination methods of the first to seventh determination methods continues for 3 seconds. Then, when the synchronization signal is not determined to be stable for 20 seconds after the signal detector 16 starts detecting the synchronization signal (the synchronization signal continues for 20 seconds by any one of the first to seventh determination methods). The synchronization signal of the acquired video signal is determined to be abnormal. The 20 seconds is an example of the “first time” in the present invention. The above 3 seconds is an example of the “second time” in the present invention.

  In the first embodiment, when the CPU 11 of the television apparatus 1 determines that the synchronization signal of the acquired video signal is abnormal, the EDID transmitted before determining that the synchronization signal is abnormal is included. An EDID including the lowest image quality as the highest image quality is transmitted to the hard disk recorder 2 via the HDMI terminal 15, and a video signal based on the EDID including the lowest image quality as the highest image quality is transmitted from the hard disk recorder 2. It is configured to perform acquisition control. Note that a video signal with lower image quality has a property that the synchronization signal is less likely to become unstable because the period of the synchronization signal is longer than that of a video signal with higher image quality.

  For example, when the highest image quality included in the EDID before determining that the synchronization signal of the video signal acquired by the CPU 11 of the television apparatus 1 is abnormal is the resolution 2160p, the CPU 11 synchronizes the acquired video signal. After determining that the signal is abnormal, control is performed to change the information with the highest image quality having the resolution 1080p instead of the information with the highest image quality having the resolution 2160p. Then, after changing the EDID, the CPU 11 changes the voltage level applied to the hot plug detection terminal from High to Low, and then performs control to change from Low to High.

  The CPU 21 of the hard disk recorder 2 is configured to detect the voltage level of the hot plug detection terminal and perform control to acquire the changed EDID when the voltage level changes from Low to High. The CPU 21 is configured to read from the hard disk recorder 2 a video signal corresponding to the changed EDID (a video signal that can be displayed as a resolution corresponding to 1080p). Then, the CPU 21 of the hard disk recorder 2 is configured to transmit a video signal corresponding to the changed EDID to the television device 1 via the HDMI terminal 22.

  Then, the CPU 11 of the television apparatus 1 is configured to acquire a video signal corresponding to the EDID transmitted from the hard disk recorder 2 and changed by the television apparatus 1 via the HDMI terminal 15. The CPU 11 is configured to display the acquired video signal on the display unit 12.

  In the first embodiment, the CPU 11 of the television apparatus 1 receives a video signal based on the changed EDID (the highest image quality is resolution 1080p) from the hard disk recorder 2, and a synchronization signal described later. If it is determined that the synchronization signal is abnormal based on the determination method, an EDID having the highest image quality with a lower image quality (for example, resolution 1080i) than the changed EDID (the highest image quality is resolution 1080p) is selected. In this case, control for transmission to the hard disk recorder 2 is performed. That is, the CPU 11 is configured to perform processing for further changing the information included in the EDID, and to perform control for transmitting the changed EDID (the highest image quality is resolution 1080i) to the hard disk recorder 2. . Then, the CPU 21 of the hard disk recorder 2 is configured to transmit a video signal based on the acquired further changed EDID (the highest image quality is resolution 1080i) to the television apparatus 1.

  Then, the CPU 11 of the television apparatus 1 determines whether or not the synchronization signal is abnormal, and performs control to repeat the above EDID change process until it is determined that the synchronization signal is not abnormal. It is configured. Then, the CPU 11 displays on the display unit 12 a video signal based on EDID, which is the lowest image quality (for example, resolution 480p) of the image quality that can be displayed by the display unit 12 of the television apparatus 1. If it is determined that the synchronization signal is abnormal, a cable abnormality notification display (see FIG. 2) is displayed on the display unit 12.

  Specifically, as shown in FIG. 2, the CPU 11 of the television apparatus 1 displays a video signal based on EDID, which is the highest image quality among the displayable image quality, on the display unit 12. If there is, the control for notifying the user of the cable abnormality is performed without performing the control for changing the EDID. For example, the CPU 11 displays on the display unit 12 via the OSD unit 18 "There is a possibility that there is a problem with the cable.", "Please replace the cable." May be improved "is displayed.

  In the first embodiment, the CPU 11 of the television apparatus 1 is in an on state from a state in which the power source of the television apparatus 1 is turned off (a state in which power is supplied from the power supply unit 19 to the entire television apparatus 1). Is switched to the hard disk recorder 2, the EDID transmitted to the television apparatus 1 in the ON state immediately before the power of the main body of the television apparatus 1 is turned off. For example, in a state where the power source of the television device 1 is turned on and the television device 1 displays a video signal based on EDID having the highest image quality with a resolution of 720p on the display unit 12, the operation unit 20 The CPU 11 is configured to perform control to turn off the power of the television apparatus 1 main body when receiving information to turn off the power of the television apparatus 1 main body based on the user's operation. ing. After that, when the operation unit 20 receives information for turning on the power of the main body of the television apparatus 1 based on a user operation, the CPU 11 transmits the information to the television apparatus 1 in the immediately previous on state. The EDID having the highest image quality with the resolution 720p is controlled to be transmitted to the hard disk recorder 2.

  Next, with reference to FIG. 3 and FIG. 4, a method for determining whether or not the synchronization signal in the television apparatus 1 of the present invention is unstable will be described. The process of determining whether or not the synchronization signal is unstable is performed by the CPU 11 of the television apparatus 1.

  As shown in FIGS. 3 and 4, in the first embodiment, as a method for determining that the synchronization signal is unstable, determination based on detection of a shift in the clock cycle of the TMDS clock signal (first determination method), H Until the acquisition of the detection by the detection of the shift of the cycle of the Sync signal (second determination method), the determination by the detection of the shift of the cycle of the V Sync signal (third determination method), and the H Sync signal and then the H Sync signal. (4th determination method) by determining whether or not the number of clocks of the TMDS clock signal detected during the period is a predetermined value, and a period until the V Sync signal and the next V Sync signal are acquired (5th determination method) by determining whether or not the number of detected H Sync signals is a predetermined value, and during the detection of the H Sync signal (the voltage level is high) State) in which the number of clocks of the TMDS clock signal is a predetermined value (sixth determination method), and the H Sync signal during detection of the V Sync signal (voltage level is in a high state) And a determination (seventh determination method) by determining whether or not the detected number is a predetermined value.

  Specifically, in the first determination method, the synchronization signal is unstable when the clock cycle of the TMDS clock signal detected by the signal detection unit 16 differs by 0.5% or more from the clock cycle of the predetermined TMDS clock signal. It is determined that For example, in the case of the video format 1080p (the general V Sync period of NTSC (National Television System Committee)), the clock period of the TMDS clock signal (predetermined value) is 148.352 MHz. That is, when the clock period of the TMDS clock signal detected by the signal detection unit 16 is a value larger than 149.092 MHz or less than 147.610 MHz, it is determined that the synchronization signal is unstable.

  In the second determination method, if the cycle of the H Sync signal detected by the signal detection unit 16 differs by 0.5% or more from the cycle of the predetermined H Sync signal, the synchronization signal is determined to be unstable. . For example, in the case of the video format 1080p, the cycle of the H Sync signal (the cycle of the predetermined H Sync signal) is 67.433 kHz. That is, when the period of the H Sync signal detected by the signal detection unit 16 is a value greater than 67.770 kHz or less than 67.095 kHz, it is determined that the synchronization signal is unstable.

  In the third determination method, when the cycle of the V Sync signal detected by the signal detection unit 16 differs by 0.5% or more from the cycle of the predetermined V Sync signal, the synchronization signal is determined to be unstable. . For example, in the case of the video format 1080p, the cycle of the H Sync signal (the cycle of the predetermined V Sync signal) is 59.94 Hz. That is, when the period of the V Sync signal detected by the signal detector 16 is a value greater than 60.24 Hz or less than 59.64 kHz, it is determined that the synchronization signal is unstable.

  Further, in the fourth determination method, the synchronization signal is unstable when the number of clocks of the TMDS clock signal detected in the period until the H Sync signal and the next H Sync signal are detected is not a predetermined number. judge. For example, in the case of the video format 1080p, the number of clocks of the TMDS clock signal (the number determined above) in a period until the H Sync signal and the next H Sync signal are acquired is 2200 clocks. That is, if the number of TMDS clock signals other than 2200 clocks is detected after the H Sync signal is detected by the signal detector 16 until the next H Sync signal is detected, the synchronization signal is unstable. Judge that there is.

  Further, in the fifth determination method, the synchronization signal is unstable when the number of detected H Sync signals detected before the V Sync signal and the next V Sync signal is not a predetermined number. judge. For example, in the case of the video format 1080p, the number (predetermined number) of H Sync signals in a period until the V Sync signal and the next V Sync signal are acquired is 1125 times. That is, if the number of H Sync signals is detected other than 1125 times during the period from when the V Sync signal is detected by the signal detector 16 until the next V Sync signal is detected, the synchronization signal is unstable. Judge that there is.

  In the sixth determination method, the synchronization signal is determined to be unstable when the number of clocks of the TMDS clock signal during detection of the H Sync signal (voltage level is High) is not a predetermined number. For example, in the case of the video format 1080p, the number of clocks (predetermined number) of the TMDS clock signal during detection of the H Sync signal is 44 clocks. That is, when the number of TMDS clock signals other than 44 is detected by the signal detection unit 16 during detection of the H Sync signal, it is determined that the synchronization signal is unstable.

  In the seventh determination method, when the number of H Sync signals during detection of the V Sync signal (the voltage level is High) is not a predetermined number, it is determined that the synchronization signal is unstable. For example, in the case of the video format 1080p, the number (predetermined number) of H Sync signals during detection of the V Sync signal is five. That is, when the signal detection unit 16 detects the number of H Sync signals other than five during the detection of the V Sync signal, it determines that the synchronization signal is unstable.

  Next, with reference to FIG. 5, the synchronization signal abnormality determination and EDID transmission / reception control processing flow of the display system 100 according to the first embodiment will be described. Processing in the television apparatus 1 is performed by the CPU 11. The processing in the hard disk recorder 2 is performed by the CPU 21.

  First, as shown in FIG. 5, in step S1, the voltage level of the hot plug detection terminal is changed from Low to High. Thereafter, the process proceeds to step S2. In step S2, the television apparatus 1 receives the EDID request signal transmitted from the hard disk recorder 2 to the television apparatus 1 in step S12 to be described later, and EDID is transmitted from the television apparatus 1 to the hard disk recorder 2. Is called. Thereafter, the process proceeds to step S3.

  In step S3, the synchronization signal of the video signal detected by the signal detector 16 is acquired. That is, the synchronization signal of the video signal is acquired based on the EDID transmitted from the hard disk recorder 2 in step S14 described later. Thereafter, the process proceeds to step S4. In step S4, it is determined whether the synchronization signal of the video signal is abnormal. That is, when the synchronization signal is abnormal in the above-described determination method, the process proceeds to step S5, and when the synchronization signal is not abnormal, the process proceeds to step S7.

  In step S5, an EDID change process (see FIG. 6), which will be described later, is executed. Then, it progresses to step S6. In step S6, the voltage level applied to the hot plug detection terminal is changed from High to Low. Then, it returns to step S1. That is, after the voltage level applied to the hot plug detection terminal is changed from High to Low, the voltage level applied to the hot plug detection terminal is changed again from Low to High in Step S1, thereby the hard disk recorder 2 The EDID is read again by. As a result, the television apparatus 1 can acquire a video signal based on the EDID changed in step S5.

  Moreover, EDID is memorize | stored in step S7 which progresses when a synchronous signal is not abnormal in step S3. That is, the EDID in which the synchronization signal is not abnormal is stored. For example, when it is determined that the synchronization signal corresponding to the EDID having the highest image quality with the resolution 1080p is abnormal, and it is determined that the synchronization signal corresponding to the EDID having the highest image quality with the resolution 1080i is not abnormal, EDID having the highest image quality of 1080i is stored in the memory 17. Thereafter, the abnormality determination of the synchronization signal and the EDID transmission / reception control processing by the television apparatus 1 are ended.

  On the other hand, in step S11, the hard disk recorder 2 determines whether or not the voltage level of the hot plug detection terminal has been changed from low to high. This step is repeated until the voltage level is changed from Low to High. When the voltage level is changed from Low to High, the process proceeds to Step S12. In step S12, an EDID request signal is transmitted.

  In step S13, EDID is acquired. That is, the EDID transmitted from the television device 1 in step S2 described above is acquired via the HDMI terminal 22. Thereafter, the process proceeds to step S14. In step S14, the video signal read from the hard disk drive 23 based on the EDID acquired in step S13 is transmitted to the television apparatus 1 via the HDMI terminal 22. Then, it returns to step S11.

  Next, an EDID change control process flow of the television device 1 according to the first embodiment will be described with reference to FIG. Processing in the television apparatus 1 is performed by the CPU 11.

  First, as shown in FIG. 6, in step S <b> 21, it is determined whether or not the highest resolution among the resolutions corresponding to EDID is the lowest resolution that can be displayed on the display unit 12. For example, when the changeable resolution is configured as a resolution of 2160p, 1080p, 1080i, 720p, and 480p, whether the highest resolution among the corresponding resolutions of EDID is the EDID that matches the lowest 480p or not Is determined. If the highest resolution of EDID does not match the lowest resolution, the process proceeds to step S22. If the highest resolution of EDID matches the lowest resolution, the process proceeds to step S23. In step S22, the highest resolution information included in the EDID is changed to one step lower resolution information. That is, when the resolution is 2160p, the resolution is changed to 1080p, and when the resolution is 1080p, the resolution is changed to 1080i. Thereafter, the EDID change control process flow by the television apparatus 1 is terminated.

  Further, in step S23, which proceeds to the case of the lowest resolution in step S21, a cable abnormality notification display (see FIG. 2) is performed. Thereafter, the EDID change control process flow by the television apparatus 1 is terminated.

  In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, when the CPU 11 of the television apparatus 1 determines that the synchronization signal of the acquired video signal is unstable for 20 seconds, the highest image quality included in the EDID ( For example, EDID, which is information including the highest image quality having a lower image quality (for example, resolution 1080p) than the resolution 2160p) is transmitted to the hard disk recorder 2, and the image quality with the highest EDID (in this case, resolution 1080p) is transmitted from the hard disk recorder 2. ) To obtain a video signal based on the above, when the period of the synchronization signal is not constant and the normal display is possible with a limited short period (when the synchronization signal is not unstable) Is not determined to be unstable, and is normally displayed on the display unit 12 (display of high-quality video) It can be inhibited from determining impossible if capable of performing. As a result, since it is possible to suppress the display of the low-quality image on the display unit 12 in a state where the synchronization signal is not unstable, it is possible to suppress the deterioration of the image quality as much as possible.

  In the first embodiment, as described above, the synchronization signal includes a clock signal, a horizontal synchronization signal, and a vertical synchronization signal, and the CPU 11 of the television apparatus 1 is connected to the TMDS clock signal, the H Sync signal, and V It is determined whether or not at least two synchronization signals of the Sync signal are unstable, and the state where it is determined that any one of the synchronization signals is unstable continues for 20 seconds. In this case, EDID, which is information including the highest image quality including lower image quality (for example, resolution 1080p) than the highest image quality (for example, resolution 2160p) included in EDID, is transmitted to hard disk recorder 2 via HDMI terminal 15. It is configured to perform control. This makes it possible to determine whether or not the synchronization signal is unstable more accurately than when determining whether or not it is unstable based on only one synchronization signal (for example, only the TMDS clock signal). can do.

  In the first embodiment, as described above, after the CPU 11 of the television apparatus 1 acquires the H Sync signal, the number of clocks of the TMDS clock signal is the first period until the H Sync signal is acquired next. If the number is different from a predetermined number of 1 (for example, 2200 clocks), or after acquiring the V Sync signal, the number of detected H Sync signals is the second period after acquiring the V Sync signal. When the synchronization signal is determined to be unstable when the number is different from a predetermined number (for example, 1125 times), the state in which the synchronization signal is determined to be unstable continues for 20 seconds. EDID, which is information including the highest image quality having a lower image quality (for example, resolution 720p) than the highest image quality (for example, resolution 1080p) included in It is configured to perform control to transmit to the disk recorder 2 via the HDMI terminal 15. Thereby, the number of clocks of the TMDS clock signal is compared with the first predetermined number (for example, 2200 clocks), or the number of detections of the H Sync signal is compared with the second predetermined number (for example, 1125 times). By performing the above, it can be easily determined whether or not the synchronization signal is unstable.

  In the first embodiment, as described above, the CPU 11 of the television apparatus 1 sets the resolution 1080p to the highest image quality from the changed EDID (for example, the information that sets the highest image quality resolution 2160p to the highest image quality). When the video signal is received from the hard disk recorder 2 based on the information changed to the information to be synchronized), and the synchronization signal is determined to be unstable for a predetermined first time (for example, 20 seconds). Is configured to perform control to transmit to the hard disk recorder 2 an EDID including the highest image quality having a lower image quality (for example, resolution 720p) than the highest image quality (in this case, resolution 1080p) included in the EDID. . Thereby, since the image quality of the image displayed on the display unit 12 can be lowered step by step, the image with the highest image quality performance among the displayable image quality performances can be displayed on the display unit 12.

  In the first embodiment, as described above, when the CPU 11 of the television apparatus 1 is switched from the off state to the on state, the television apparatus 1 body is turned off. The EDID transmitted to the hard disk recorder 2 immediately before being turned on is controlled to be transmitted to the hard disk recorder 2. Thereby, when the power source of the television apparatus 1 main body is switched from the off state to the on state, the CPU 11 does not need to determine again whether or not the synchronization signal is unstable, and thus performs unnecessary control. Since it is not necessary, the burden on the CPU 11 can be reduced.

  In the first embodiment, as described above, the display system 100 includes the HDMI cable 3 capable of transmitting a video signal and EDID based on the HDMI standard. Thereby, in the HDMI standard, since EDID can be transmitted via the standardized DDC terminal, the EDID can be easily transmitted to the hard disk recorder 2.

(Second Embodiment)
Next, the configuration of the display system 101 according to the second embodiment will be described with reference to FIG. In the second embodiment, a video signal based on EDID including the image quality lower than the highest image quality that can be displayed by the display unit as information of the highest image quality is transmitted from the hard disk recorder to the HDMI terminal, and other than the video from the hard disk recorder When the video is displayed on the display unit, it is configured to further control to transmit EDID including information of the highest image quality that can be displayed on the display unit to the hard disk recorder.

  As shown in FIG. 1, a display system 101 according to the second embodiment includes a television device 1a, a hard disk recorder 2, and an HDMI cable 3 configured to connect the television device 1a and the hard disk recorder 2. . The television apparatus 1a includes a CPU 11a.

  Here, in the second embodiment, the CPU 11a of the television apparatus 1a includes the image quality (for example, resolution 1080p) lower than the highest image quality (for example, resolution 2160p) that can be displayed by the display unit 12 as the information of the highest image quality. A video signal based on EDID is transmitted from the hard disk recorder 2 to the HDMI terminal 15, and a video other than the video from the hard disk recorder 2 (for example, a program received from the broadcast receiving unit 13) is displayed on the display unit 12. The display unit 12 is configured to perform control to transmit EDID including information on the highest image quality (for example, resolution 2160p) that can be displayed to the hard disk recorder 2.

  When the CPU 11a of the television device 1a acquires the synchronization signal via the HDMI terminal 15 and determines that the acquired synchronization signal is not abnormal (that is, when a stable state continues for a predetermined 3 seconds). Instead of EDID including low image quality (for example, resolution 1080p) as the highest image quality information, EDID including information of the highest image quality (for example, resolution 2160p) that can be displayed by display unit 12 is transmitted to hard disk recorder 2. It is configured to perform control. The determination method as to whether or not the synchronization signal is unstable (stable) is configured to be determined by the same method as the determination method of the television device 1 according to the first embodiment, and the CPU 11a When the acquired synchronization signal is unstable for 20 seconds, the synchronization signal is determined to be abnormal. Other configurations of the display system 101 according to the second embodiment are the same as those of the display system 100 according to the first embodiment.

  Next, with reference to FIG. 7, the synchronization signal abnormality determination and EDID transmission / reception control processing flow of the display system 101 according to the second embodiment will be described. Note that the processing in the television device 1a is performed by the CPU 11a. The processing in the hard disk recorder 2 is performed by the CPU 21.

  First, as shown in FIG. 7, in the television device 1a, in step S31, it is determined whether or not the EDID is information including information on the highest image quality (for example, resolution 2160p) that can be displayed on the display unit 12. The This determination is repeated when the EDID includes information of the highest image quality that can be displayed, and when the EDID does not include information of the highest image quality that can be displayed, the process proceeds to step S32.

  In step S32, it is determined whether or not a video other than the video transmitted from the hard disk recorder 2 is displayed on the display unit 12 (for example, a program received by the broadcast receiving unit 13). If a video other than the video transmitted from the hard disk recorder 2 is displayed on the display unit 12, the process proceeds to step S33. If a video transmitted from the hard disk recorder 2 is displayed on the display unit 12, The process returns to step S31.

  In step S33, the EDID is changed to information including the highest image quality (for example, resolution 2160p) that can be displayed on the display unit 12. Thereafter, the process proceeds to step S34. In step S34, the voltage level of the hot plug detection terminal is changed from Low to High. Thereafter, the process proceeds to step S35.

  In step S35, EDID is transmitted. That is, in step S34, after the hard disk recorder 2 detects that the voltage level of the hot plug detection terminal has been changed from low to high, the hard disk recorder 2 transmits an EDID request signal to the television device 1a (step S34). S12). Thereafter, an EDID request signal is transmitted from the hard disk recorder 2 to the television apparatus 1a, and the television apparatus 1a receives the EDID request signal. Then, EDID including information of the highest image quality that can be displayed on the display unit 12 is transmitted from the television device 1 a to the hard disk recorder 2. Thereafter, the process proceeds to step S36. In step S36, the synchronization signal of the video signal is acquired. Thereafter, the process proceeds to step S37.

  In step S37, it is determined whether the synchronization signal of the video signal is abnormal. If the video signal synchronization signal is abnormal, the process proceeds to step S38. If the video signal synchronization signal is not abnormal, the process proceeds to step S39. In step S38, the EDID is changed from the EDID including the highest image quality information that can be displayed on the display unit 12 to the EDID immediately before the change from the EDID including the highest image quality information that can be displayed on the display unit 12. (Returned).

  In step S39, the EDID is stored in the memory 17. That is, in step S37, even if the video signal is based on EDID including the highest image quality information that can be displayed on the display unit 12, if the synchronization signal is not abnormal, the highest image quality information that can be displayed on the display unit 12 is displayed. When the EDID request signal is received from the hard disk recorder 2, the EDID including the highest image quality information that can be displayed on the display unit 12 is transmitted. On the other hand, when the synchronization signal of the video signal based on the EDID including the highest image quality information that can be displayed on the display unit 12 is abnormal in step S37, the EDID including the highest image quality information that can be displayed on the display unit 12 is set. The EDID returned to the EDID immediately before the change is stored. When the EDID request signal is received from the hard disk recorder 2, the returned EDID is transmitted. Thereafter, the abnormality determination of the synchronization signal and the EDID transmission / reception control processing flow in the television apparatus 1a are ended.

  As shown in FIG. 7, steps S11 to S14 in the hard disk recorder 2 are the same as steps S11 to S14 (see FIG. 5) in the synchronization signal determination and EDID change control processing of the display system 100 according to the first embodiment. Similar processing is performed.

  In the second embodiment, the following effects can be obtained.

  In the second embodiment, as described above, the CPU 11a of the television device 1a causes the changed EDID (for example, the information that makes the resolution 1080p the highest image quality from the information that makes the resolution 2160p that is the highest image quality the highest image quality). The video signal based on the video signal from the hard disk recorder 2 is transmitted to the HDMI terminal 15 and a video other than the video from the hard disk recorder 2 (for example, a program received from the broadcast receiving unit 13) is displayed on the display unit. 12, the display unit 12 is configured to perform control to transmit EDID including information of the highest image quality (in this case, resolution 2160p) that can be displayed to the hard disk recorder 2.

  By configuring as described above, even when the EDID that has been determined to be unstable in the past and has been changed and transmitted to the hard disk recorder 2 is changed from a state in which the synchronization signal is unstable to a state that is not unstable. In this case, the EDID including the highest image quality information that can be displayed on the display unit 12 is transmitted to the hard disk recorder 2, and the video based on the EDID including the highest image quality information that can be displayed on the display unit 12 from the hard disk recorder 2. Can be obtained. For example, when the user replaces the HDMI cable 3 with a shorter HDMI cable 3 or a high-quality HDMI cable 3, the synchronization signal may change from an unstable state to an unstable state. In such a case, by configuring as described above, it is possible to effectively suppress display of a low-quality image on the display unit 12 in a state where the synchronization signal is not unstable.

  Further, in the second embodiment, as described above, when the synchronization signal acquired via the HDMI terminal 15 continues to be stable for a predetermined second time (for example, 3 seconds), the CPU 11a receives the synchronization signal. It is determined that it is not unstable, and instead of the changed EDID (for example, a state in which the resolution 2160p, which is the highest image quality, is changed to the information having the highest image quality with the resolution 1080p), the display is changed. The unit 12 is configured to perform control to transmit EDID including information of the highest image quality (in this case, resolution 2160p) that can be displayed to the hard disk recorder 2. Thereby, since it can suppress determining that a synchronous signal is not unstable in the time when the stable state of the synchronous signal was limited, it can determine more accurately that a synchronous signal is not unstable. .

  In the second embodiment, as described above, the second time (3 seconds) is configured to be shorter than the first time (20 seconds). Here, once the synchronization signal is detected, if the synchronization signal continues to be stable for a certain period of time, the synchronization signal is stable even after the synchronization signal has been stabilized for a certain period of time. In many cases, this situation continues. Therefore, in the present invention, the second time (3 seconds) is configured to be shorter than the first time (20 seconds), so that the determination can be made in a shorter time when the synchronization signal is not unstable. . Other effects of the display system 101 according to the second embodiment are the same as those of the display system 100 according to the first embodiment.

(Third embodiment)
Next, the configuration of the display system 102 according to the third embodiment will be described with reference to FIG. In the third embodiment, unlike the display system 100 according to the first embodiment, which is configured to change only the resolution information as the changeable image quality information in the EDID, the EDID is the number of pixels in the horizontal direction. 4k2k image quality information indicating that it is compatible with 4k2k image quality exceeding the resolution (resolution 1080p) with 1920 and 1080 pixels in the vertical direction, and deep color indicating that it corresponds to the deep color function Information.

  As shown in FIG. 1, the display system 102 according to the third embodiment includes a television device 1b, a hard disk recorder 2, and an HDMI cable 3 configured to be able to connect the television device 1b and the hard disk recorder 2. . The television apparatus 1b includes a CPU 11b.

  Here, in the third embodiment, the EDID corresponds to a resolution 2160p in which the number of pixels in the horizontal direction is 3840 and the number of pixels in the vertical direction is 2160, and an image quality function corresponding to the resolution 2160p (4k2k image quality). 4k2k image quality information indicating that the image data is supported and deep color information indicating that the image data is compatible with the deep color function. Further, the EDID of the television apparatus 1b is obtained from the resolution 2160p by the CPU 11b from 4k2k incompatible information indicating that the image quality is not compatible with 4k2k, deep color incompatible information indicating that it does not support deep color, and resolution 2160p. And information corresponding to a plurality of lower resolutions (1080p, 1080i, 720p, 480p). The 4k2k image quality information is an example of the “first resolution information” in the present invention. The 4k2k non-corresponding information is an example of the “first non-corresponding information” in the present invention. The deep color non-corresponding information is an example of the “second non-corresponding information” in the present invention. The information corresponding to a plurality of resolutions (1080p, 1080i, 720p, 480p) lower than the resolution 2160p is an example of “second resolution information” in the present invention. Other configurations of the display system 102 according to the third embodiment are the same as those of the display system 100 according to the first embodiment.

  Next, referring to FIG. 5 and FIG. 8, the synchronization signal abnormality determination and EDID transmission / reception control processing (see FIG. 5) and EDID change control processing (see FIG. 8) flow of the display system 102 according to the third embodiment. Will be described. The processing in the television device 1b is performed by the CPU 11b. The processing in the hard disk recorder 2 is performed by the CPU 21.

  First, as shown in FIG. 5, steps S1 to S4 and S6 to S14 in the synchronization signal abnormality determination and EDID transmission / reception control processing of the display system 102 according to the third embodiment are displayed according to the first embodiment. Processing is performed in the same manner as steps S1 to S4 and steps S6 to S14 (see FIG. 5) in the synchronization signal abnormality determination and EDID transmission / reception control processing of system 100. In step S5, the display system 102 according to the third embodiment performs EDID change control processing different from that of the display system 100 according to the first embodiment, as shown in FIG.

  As shown in FIG. 8, in the television device 1b, in step S41, it is determined whether or not the EDID includes 4k2k image quality information. If 4k2k image quality information is included, the process proceeds to step S42. If 4k2k image quality information is not included, the process proceeds to step S43. In step S42, the EDID is changed to include 4k2k non-corresponding information. Thereafter, the EDID change control process of the display system 102 is terminated.

  In step S43, which is the case where 4k2k image quality information is not included in step S41, it is determined whether or not EDID includes deep color information. If deep color information is included, the process proceeds to step S44. If deep color information is not included, the process proceeds to step S45. In step S44, the EDID is changed to include deep color non-corresponding information. Thereafter, the EDID change control process of the display system 102 is terminated.

  Further, in step S45, which proceeds when no deep color information is included in step S43, it is determined whether or not the highest resolution included in the EDID is the lowest resolution that can be displayed on the display unit 12. For example, when the lowest resolution that can be displayed on the display unit 12 is the resolution 480p, it is determined whether or not the highest resolution among the corresponding resolutions of the EDID matches the lowest resolution 480p. If it matches the minimum resolution, the process proceeds to step S47, and if it does not match the minimum resolution, the process proceeds to step S46. In step S46, the EDID is changed to information having the highest resolution of one step lower resolution (for example, 1080i for 1080p, 720p for 1080i, and 480p for 720p). Thereafter, the EDID change control process of the display system 102 is terminated. That is, when the EDID change control process is executed again after the EDID has been changed to a resolution that is one step lower, the highest resolution is changed to a lower resolution by one step for each determination.

  Then, in step S47, which proceeds when information of the lowest resolution that can be displayed on the display unit 12 is included in step S45, a cable abnormality notification display (see FIG. 2) is displayed on the display unit 12. Thereafter, the EDID change control process of the display system 102 is terminated. After the EDID change control process is completed, it is determined again whether or not the synchronization signal is abnormal (step S4 in FIG. 5). If it is determined that the synchronization signal is abnormal, the process again The EDID change control process of the display system 102 is executed.

  In the third embodiment, the following effects can be obtained.

  In the third embodiment, as described above, EDID corresponds to a resolution exceeding the resolution in which the number of pixels in the horizontal direction is 1920 and the number of pixels in the vertical direction is 1080 (for example, resolution 2160p). 4k2k image quality information and deep color information indicating that it supports the deep color function, and the changed EDID does not support 4k2k image quality. And deep color non-corresponding information indicating that it does not support deep color, and resolution information corresponding to a plurality of resolutions lower than the resolution 2160p (for example, 1080p, 1080i, 720p, 480p). . When the CPU 11b determines that the synchronization signal is unstable for a predetermined first time (for example, 20 seconds), it performs control to transmit EDID including 4k2k non-corresponding information to the hard disk recorder 2. Configure as follows. If the CPU 11b determines that the synchronization signal is unstable for a predetermined first time (for example, 20 seconds) after transmitting EDID including 4k2k non-compliant information, the deep color non-compliant information is displayed. Control is performed to transmit the included EDID to the hard disk recorder 2. And after transmitting EDID including deep color non-corresponding information, if it is determined that the synchronization signal is unstable for a predetermined first time (for example, 20 seconds), it corresponds to EDID for each determination. It is configured to perform control to transmit EDID including information of the highest resolution sequentially lowered from the higher one to the lower one of the plurality of resolutions.

  Here, in general, a change from a state corresponding to 4k2k image quality to a state not compatible, a change from a state corresponding to the deep color function to a state not compatible, and a change to lower the highest resolution information to the lower side. In order, the deterioration of the image quality of the video displayed on the display unit 12 is less likely to be visually recognized. Therefore, in the present invention, the CPU 11b is controlled to lower the image quality of the video in the order in which the degradation of the image quality of the video displayed on the display unit 12 is less likely to be visually recognized. This can be suppressed as much as possible. The other effects of the display system 102 according to the third embodiment are the same as those of the display system 100 according to the first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to third embodiments, the example in which the television device is used as the display device of the present invention has been shown, but the present invention is not limited to this. In the present invention, a display device other than the television device may be used. For example, a projector or the like may be used.

  In the first to third embodiments, the hard disk recorder is used as the transmission apparatus (external transmission apparatus) of the present invention. However, the present invention is not limited to this. In the present invention, a device other than the hard disk recorder may be used as the transmission device (external transmission device). For example, a Blu-ray disc recorder may be used.

  In the first to third embodiments, the example in which the synchronization signal is determined to be abnormal when the state where the synchronization signal is unstable continues for 20 seconds (first time) has been described. The invention is not limited to this. In the present invention, the first time may be a time other than 20 seconds. For example, the first time may be a time shorter than 20 seconds, or may be a time longer than 20 seconds.

  In the first to third embodiments, when the state where the synchronization signal is stable continues for 3 seconds (second time), it is determined that the synchronization signal is not unstable (not abnormal). Although shown, the present invention is not limited to this. In the present invention, the second time may be a time other than 3 seconds. For example, the second time may be a time shorter than 3 seconds, or may be a time longer than 3 seconds.

  In the first to third embodiments, the example of the resolution of 2160p, 1080p, 1080i, 720p, and 480p has been shown as the resolution that can be displayed on the display unit of the present invention. However, the present invention is not limited to this. Absent. In the present invention, the resolution may be a resolution other than 2160p, 1080p, 1080i, 720p, and 480p. For example, the display unit may be configured to display an image with a resolution exceeding 2160p, or may be configured to display an image with a resolution less than 480p.

  In the first to third embodiments, for convenience of explanation, the processing of the control unit of the present invention has been described using a flow-driven flowchart in which processing is performed in order along the processing flow. Not limited to. In the present invention, the processing operation of the control unit may be performed by event-driven (event-driven) processing that executes processing for each event. In this case, it may be performed by a complete event drive type or a combination of event drive and flow drive.

1, 1a, 1b Television device (display device)
2 Hard disk recorder (transmitter)
3 HDMI cable (predetermined cable)
11, 11a, 11b CPU (control unit)
12 Display section 15 HDMI terminal (connection section)
100, 101, 102 Display system

Claims (11)

A display unit for displaying images;
The first image quality information that is configured to be connectable to an external transmission device via a predetermined cable and includes the highest image quality that can be displayed on the display unit is transmitted to the external transmission device, and the first image quality information is also included in the first image quality information. A connection unit for receiving a video signal based on the external transmission device;
A control unit that performs control to acquire the received video signal,
The control unit, when the state in which the synchronization signal of the video signal acquired via the connection unit is determined to be unstable continues for a predetermined first time, the highest image quality included in the first image quality information The second image quality information, which is the information including the highest image quality consisting of lower image quality, is transmitted to the external transmission device via the connection unit, and the second image quality information received via the connection unit A display device configured to perform control to acquire the video signal based on the highest image quality. The synchronization signal includes a clock signal, a horizontal synchronization signal, and a vertical synchronization signal,
The controller determines whether at least two of the clock signal, the horizontal synchronization signal, and the vertical synchronization signal are unstable, and determines whether the synchronization signal is at least two of the synchronization signals. When the state where any of the synchronization signals is determined to be unstable continues for the predetermined first time, the highest image quality composed of the image quality lower than the highest image quality included in the first image quality information is obtained. The display device according to claim 1, wherein the display device is configured to perform control to transmit the second image quality information, which is included information, to the external transmission device via the connection unit.   The control unit, after acquiring the horizontal synchronization signal, when the number of clocks of the clock signal is a number different from the first predetermined number in a period until the next acquisition of the horizontal synchronization signal, or If the number of detections of the horizontal synchronization signal is different from the second predetermined number in the period from the acquisition of the vertical synchronization signal to the next acquisition of the vertical synchronization signal, the synchronization signal is not valid. It is determined that the image quality is lower than the highest image quality included in the first image quality information when the state in which the synchronization signal is determined to be unstable continues for the predetermined first time. The display device according to claim 2, configured to perform control to transmit the second image quality information, which is information including the highest image quality, to the external transmission device via the connection unit.   The control unit transmits the video signal based on the second image quality information from the external transmission device to the connection unit, and displays a video other than the video from the external transmission device on the display unit. The first image quality information is controlled to be transmitted to the external transmission device, the synchronization signal is acquired via the connection unit, and the acquired synchronization signal is determined not to be unstable. The display device according to claim 1, configured to perform control to transmit the first image quality information to the external transmission device instead of the second image quality information.   The control unit determines that the synchronization signal is not unstable when a stable state of the synchronization signal acquired via the connection unit continues for a predetermined second time, and replaces the second image quality information. The display device according to claim 4, wherein the display device is configured to perform control to transmit the first image quality information to the external transmission device.   The display device according to claim 5, wherein the second time is shorter than the first time.   The control unit receives the video signal based on the second image quality information from the external transmission device, and determines that the synchronization signal is unstable for a predetermined first time. Is configured to perform control to transmit information including the highest image quality including the image quality lower than the highest image quality included in the second image quality information to the external transmission device. The display device according to any one of 1 to 6. The first image quality information includes first resolution information indicating that it corresponds to a first resolution exceeding a resolution in which the number of pixels in the horizontal direction is 1920 and the number of pixels in the vertical direction is 1080; and a deep color function Including deep color information indicating that it supports
The second image quality information includes first non-corresponding information indicating that it does not correspond to the first resolution, second non-corresponding information indicating that it does not correspond to the deep color, and the first resolution. Second resolution information corresponding to a plurality of low second resolutions,
The control unit transmits the second image quality information including the first non-corresponding information to the external transmission device when it is determined that the synchronization signal is unstable for the predetermined first time. If it is determined that the synchronization signal is unstable for a predetermined first time after transmitting the second image quality information including the first non-compliant information, the second non-compliant Control is performed to transmit the second image quality information including information to the external transmission device, and after transmitting the second image quality information including the second non-corresponding information, the synchronization signal continues for the predetermined first time. If it is determined that the second resolution information is unstable, the second image quality including information of the highest resolution that is sequentially lowered from the higher one of the plurality of resolutions corresponding to the second resolution information to the lower one for each determination. Controls transmission of information to the external transmission device. And it is configured to display device according to claim 7.   When the power of the display device main body is switched from an off state to an on state, the control unit transmits the first image quality transmitted to the external transmission device to an on state immediately before the display device main body is turned off. The display device according to claim 1, wherein the display device is configured to perform control to transmit information or the second image quality information to the external transmission device.   10. The HDMI cable according to claim 1, wherein the predetermined cable is an HDMI cable capable of transmitting the video signal, the first image quality information, and the second image quality information based on an HDMI standard. Display device. The first image quality information that is information including the highest image quality that can be displayed by the display unit of the display device is acquired from the display device via a predetermined cable, and the video signal based on the acquired first image quality information is displayed. A transmitting device for transmitting to the device;
The display unit that displays the video, and the transmission device are configured to be connectable via the predetermined cable. The first image quality information is transmitted to the transmission device and is based on the first image quality information. A display device including a connection unit that receives the video signal from the transmission device and a display device side control unit that performs control to acquire the received video signal;
The display device side control unit is included in the first image quality information when a state in which the synchronization signal of the video signal acquired via the connection unit is determined to be unstable continues for a predetermined first time. The second image quality information that is the information including the highest image quality that is lower than the highest image quality is transmitted to the transmission device via the connection unit, and is received via the connection unit. A display system configured to perform control to acquire the video signal based on the image quality with the highest information.

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