JP2007241261A - Display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate the type of video signal in a display device with high accuracy, using a common input terminal for inputting different video signals. <P>SOLUTION: The display apparatus includes an input terminal 3 in which an analog RGB signal and a component video signals are input; synchronization signal separation section 8, configured to separate a synchronization signal from a video signal entered to the input terminal 3; an input signal processing section 11 that measure the frequencies of the synchronization signals and a control section 1, that discriminates the video signal input in the input terminal 3 from the type of the synchronization signal separated by the synchronization signal separation section 8 and the frequencies measured by the input signal processing part 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device. The display device of the present invention can be applied to, for example, a liquid crystal projector device, a projection display device such as a DLP (Digital Light Processing) projector device, a liquid crystal display, and the like.

  In a display device, for example, a projection-type display device, a device that corresponds to a large number of inputs such as a digital RGB signal, an analog RGB signal of a computer, a component video signal of an AV device, an S video signal, and a composite video signal has become mainstream. Different input terminals may be provided on the display device for these various inputs. However, in order to save space, an example is also known in which an input terminal is also used for different signals (for example, an analog RGB signal and a component video signal).

  Each input can be selected by an operation of the user from an input selection menu of OSD (On Screen Display) as shown in FIG. FIG. 2 shows an example in which analog RGB input is focused (selected).

Patent Document 1 is known for details of resolution setting according to a synchronization signal.
Japanese Patent Laid-Open No. 9-200690

  When an input is selected from the OSD input selection menu, the color space for processing the signal is determined by the input selection without depending on the input signal. Therefore, if the same input terminal is used for the analog RGB signal and the component video signal, if the input selection is wrong, the image will be displayed, but the color will be strange, so the user will think that it has failed. There was a case.

  There is also known a display device having an auto search function for successively switching input selection until an input signal is found. Even in a display device having such an auto search function, when the same input terminal is used to input different signals, signals may be erroneously detected depending on the order of auto search. For example, even if a component video signal is input, if auto search is performed in order from the input type in FIG. 9, it may be erroneously detected as analog RGB.

  An exemplary object of the present invention is to provide a display device capable of discriminating an input signal with higher accuracy than in the past even when the same input terminal is used to input different video signals. It is to provide.

  An exemplary display device of the present invention includes an input terminal into which different video signals can be input, a synchronization signal separation unit that separates synchronization signals in the video signals input to the input terminals, and a frequency of the synchronization signal. A frequency measurement unit; and an input signal discrimination unit that discriminates a video signal input to the input terminal from the type of the synchronization signal separated by the synchronization signal separation unit and the measurement result of the frequency measurement unit.

  According to the display device of the present invention, even when the same input terminal is used to input different video signals, the input signal can be discriminated with higher accuracy than before.

  Embodiments of a display device according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a block diagram of the projection display device of the first embodiment.

  In FIG. 1, the control unit 1 controls each unit in the display device according to various programs stored in the memory 12. Although details will be described later, the control unit 1 also operates as an input signal determination unit. The memory 12 also stores a signal timing list as shown in FIG. The signal timing list shows the frequency of the synchronization signal (horizontal / vertical) corresponding to each video signal standard, sampling clock, resolution (horizontal / vertical), display start position (horizontal / vertical), and whether it is a component video signal. It consists of flags.

  The projection display device of this embodiment includes a plurality of input terminals. The DVI terminal 2 is an input terminal for digital RGB signals such as a computer. The D-Sub 15 pin terminal 3 is an input terminal for analog RGB signals such as computers and component video signals such as AV equipment. That is, the D-Sub 15-pin terminal 3 is an input terminal that can input different video signals. The S video terminal 4 is an input terminal for an S video signal. The composite video terminal 5 is an input terminal for a composite video signal.

  The TMDS receiver 7 converts the TMDS signal input from the DVI terminal 2 into an RGB digital signal. The synchronization signal separation unit (synchronization signal separation unit) 8 separates the synchronization signal in the video signal input from the D-Sub 15 pin terminal 3 and outputs the horizontal and vertical synchronization signals to the AD converter 9. The AD converter 9 AD-converts the input signal according to the sampling frequency, offset, and gain set by the control unit 1 and outputs an RGB digital signal or a YUV digital signal. The video decoder 10 converts the S video signal or composite video signal input from the S video terminal 4 or the composite video terminal 5 into a YUV digital signal, a horizontal and vertical synchronizing signal, and outputs the YUV digital signal.

  The input signal processing unit 11 measures the frequency of the synchronization signal of the input route selected by the control unit 1 and notifies the control unit 1 of the measurement result. That is, the input signal processing unit 11 operates as a frequency measurement unit. Based on the notification from the input signal processing unit 11, the control unit 1 sets the horizontal and vertical capturing start positions and the resolution, and stores the settings in a frame buffer (not shown). If necessary, conversion from the YUV color space to the RGB color space is performed.

  The resolution conversion unit 13 reads out pixel data of an area according to the output resolution data set by the control unit 1 from the frame buffer, and executes digital zoom processing, trapezoid correction processing, and aspect ratio conversion processing.

  The OSD processing unit 14 reads and superimposes the image stored in the OSD image memory unit 15 on the area set by the control unit 1 with respect to the video signal input from the resolution conversion unit 13. The OSD image memory unit 15 is a nonvolatile memory and stores images such as menus. The display unit 16 projects the video signal input from the OSD processing unit 14 on the screen.

Next, the operation of input selection will be described. In this configuration example, the following input selection is permitted.
Digital RGB: input to DVI terminal 2 Analog RGB / component video: input to D-Sub 15 pin terminal 3 S video: input to S video terminal 4 Composite video: input to composite video terminal 5 Each input is shown in FIG. As shown in FIG. 4, the selection can be made by the OSD input selection menu. In FIG. 1, the key layout for selecting the input selection menu is omitted. For example, the input selection menu is opened with the Input key, the desired input is focused with the up and down buttons, and the OK button is used for determination and input. The selection menu is closed. FIG. 2 shows an example in which the analog RGB / component video input is focused.

  In the following, the flow up to storing in the frame buffer will be described for each input.

  The digital RGB input is input to the DVI terminal 2 as the TMDS signal S1 and input to the TMDS receiver 7 as it is. The TMDS receiver 7 converts the TMDS signal 2 into an RGB digital signal, a horizontal synchronization signal, and a vertical synchronization signal S 7 and outputs the converted signal to the input signal processing unit 11. The input signal processing unit 11 measures the frequency of the input horizontal and vertical synchronization signals and notifies the control unit 1 of the frequency. The control unit 1 searches for the timing at which the horizontal and vertical frequencies match (closest) from the signal timing list (FIG. 3) registered in the memory 12. In accordance with the retrieved timing table, the registered horizontal and vertical capture positions and resolution are set in the input signal processing unit 11. The input signal processing unit 11 saves the result of capturing according to the set value in the frame buffer.

  For the S video input, the YC signal S5 is input from the S video terminal 4 and input to the video decoder 10 as it is. The video decoder 10 determines the signal format such as NTSC, PAL, and SECAM from the frequency of the synchronization signal included in the Y signal and the burst signal included in the C signal, and selects the demodulation method. Demodulation and sampling are performed using the selected demodulation method, and the result is output to the input signal processing unit 11 as YUV digital, horizontal synchronization, and vertical synchronization signal S9. The input signal processing unit 11 measures the frequency of the input horizontal and vertical synchronization signals and notifies the control unit 1 of the frequency as in the case of other inputs. In response to this, the control unit 1 searches the timing closest to the horizontal and vertical frequencies from the signal timing list (FIG. 3) registered in the memory 12. In accordance with the retrieved timing table, the registered horizontal and vertical capture positions and resolution are set in the input signal processing unit 11. Since the input signal is a YUV signal, the function of converting from the YUV color space to the RGB color space is set to be effective.

  For composite video input, a composite signal S6 is input from the composite video terminal 5 and input to the video decoder 10 as it is. Thereafter, the operation is almost the same as that of the S video input, and thus the description thereof is omitted.

  Analog RGB / component video input is input from the D-Sub 15-pin terminal 3. The RGB signal S2 is directly input to the AD converter 9, and the G signal, the horizontal synchronization signal, and the vertical synchronization signal S3 are input to the synchronization signal separation unit 8. The sync signal separator 8 outputs the horizontal and vertical sync signals as they are when they exist. Also, if there is no vertical sync signal and a composite sync signal exists in the horizontal sync signal line, or if no sync signal exists in the horizontal and vertical sync signal lines and a sync on green signal exists in the G signal To separate. The horizontal synchronization and vertical synchronization signal S4, which are separated by synchronization, are input to the AD converter 9. Further, the synchronization signal type is notified to the control unit 1 (input signal discrimination unit).

  In the AD converter 9, the clamp level is set to 0 level clamp for each of the RGB signals. Further, the setting values such as the sampling frequency are operated with default values, and the RGB digital, horizontal synchronization, and vertical synchronization signal S8 are output to the input signal processing unit 11. The input signal processing unit 11 measures the frequency of the input horizontal and vertical synchronization signals and notifies the control unit 1 of the frequency.

  The control unit 1 searches the timing closest to the horizontal and vertical frequencies from the signal timing list (FIG. 3) registered in the memory 12. In accordance with the retrieved timing table, the registered sampling frequency and PLL set value are set in the AD converter 9 and the horizontal / vertical capture position and resolution are set in the input signal processing unit 11.

  Here, as can be seen from the list shown in FIG. 3, the horizontal and vertical frequencies of VGA01 for analog RGB input and 480p for component video input are equal. Therefore, conventionally, VGA01 and 480p input at the same terminal cannot be distinguished. For this reason, the analog RGB input and the component video input are separated in the input selection menu as shown in FIG. 9, and the selected input method is preferentially displayed in a color space corresponding to it. This is a factor that makes the color of an image strange when an incorrect input selection is performed. In the present embodiment, not only the frequency of the synchronization signal but also the type of the synchronization signal is taken into consideration, thereby enabling discrimination between VGA01 and 480p.

  An input signal determination procedure will be described with reference to the flowcharts shown in FIGS.

  First, the flow of FIG. 4 will be described. When the synchronization signal type separated by the synchronization signal separation unit 8 is sync on green (f1) and the component video flag of the retrieved signal timing is 1 (f2), the control unit 1 uses component video. The signal is determined (f3). Otherwise, the control unit 1 determines that it is an analog RGB signal (f5). If it is a component video signal, the clamp level of the AD converter 9 is set to the middle level for the R and B signals, and the function for converting the YUV color space to the RGB color space in the input signal processing unit 11 is effectively set ( f4). The input signal processing unit 11 saves the result of capturing according to the set value in the frame buffer.

  As described above, since the VGA01 and 480p have the same horizontal and vertical frequencies and cannot be determined only by the frequency, the special processing shown in FIG. 5 is performed. If it is determined from the horizontal and vertical frequencies to be VGA01 or 480p (f6), if the synchronization signal type of the synchronization signal separation unit 8 is sync on green (f7), it is determined to be 480p (f8), otherwise If it is, VGA01 is determined (f9).

  By doing so, it is possible to correctly determine whether the input signal is an analog RGB signal or a component video signal. Based on this determination result, if the input signal is an analog RGB signal, processing in the RGB color space is applied, and if it is a component video signal, processing in the YPbPr or PCbCr color space is applied. Thereby, display in the correct color space according to the input signal is possible.

  Also, in this embodiment, the input selection is manual. However, in the auto search function that automatically skips an input that does not have an input signal, analog RGB and component video signals are similarly applied by applying this embodiment. Can be determined correctly. In this embodiment, the input signal processing unit 11 measures the frequency of the input horizontal and vertical synchronization signals. However, the synchronization signal separation unit 8 and the AD converter 9 may be anywhere as long as they have the function. . Further, although the D-Sub15 terminal is used in this embodiment, the same processing can be performed with the DVI-I terminal and the 5BNC terminal.

  FIG. 6 is a block diagram of the projection display device of the second embodiment.

  The difference from the apparatus of FIG. 1 is that a frequency measurement unit 17 is added after the synchronization signal separation unit 8. If the synchronization signal separation unit 8 can also perform frequency measurement, the frequency measurement unit 17 need not be added.

  The TMDS receiver 7 has a function of determining whether a valid TMDS signal is input from the DVI terminal 2. The video decoder 10 has a function of determining whether a YC signal or a composite video signal is input from the S video terminal 4 or the composite video terminal 5 for each input line. If the video decoder 10 does not have the above function, it is possible to connect to the surplus input of the synchronization signal separation unit 8 and determine whether or not there is a video signal.

  The frequency measurement unit 17 measures the frequencies of the horizontal and vertical synchronization signals output from the synchronization signal separation unit 8 and notifies the control unit 1 of the measured frequencies.

  In the first embodiment, only the video signal of the selected input is determined. However, in this embodiment, the presence / absence of the input video signal is periodically detected for the input that is not selected. Improve selection usability.

Input selection permits the following as in the first embodiment.
・ Digital RGB: Input to DVI terminal 2 ・ Analog RGB / component video: Input to D-Sub 15 pin terminal 3 ・ S video: Input to S video terminal ・ Composite video: Input to composite video terminal Each input is shown in FIG. In this way, it can be selected by the OSD input selection menu. In the input selection menu of this embodiment, an icon is displayed on the right side of the input name for an input that can be determined to have an input video signal based on the detection result. When the Input key is pressed while the input selection menu is open in this way, the focus shifts to an input that has been confirmed to have a synchronization signal, and the input selection is also switched. In FIG. 7, the analog RGB input is focused, and it is determined that the digital RGB input, the analog RGB input, and the S-video input have a video signal. When the Input key is pressed in this state, another input confirmed to have a synchronization signal, for example, an S video input is selected.

  A method for determining the presence or absence of a synchronization signal will be described.

  The digital RGB input monitors the function of determining whether or not a valid TMDS signal is input from the TMDS receiver 7 every several hundreds of milliseconds, and uses the result.

  Since the analog RGB input and the component input have the same input terminal as the D-Sub 15-pin terminal 3, it is necessary to determine whether or not there is a video signal in common. The determination method will be described with reference to FIG.

  First, in response to the result of the sync signal type of the sync signal separation unit 8, when a horizontal / vertical sync signal or a composite sync signal exists (f10), there is no component video input signal (f19) and an analog RGB input signal ( f20) is set. When the horizontal / vertical sync signal or the composite sync signal does not exist (f10) and the sync on green signal exists (f11), the sync on green sync signal frequency is measured (f14). Further, the signal timing list (FIG. 5) is searched (f15), and the one with the closest synchronization signal frequency is selected.

  If the component video flag of the selected timing data is 1 (f16), it is set that there is a component video input signal (f17) and no analog RGB input signal (f18). If the component video flag of the selected timing data is not 1 (f16), it is set that there is no component video input signal (f19) and an analog RGB signal is input. If there is no horizontal / vertical sync signal or composite sync signal (f10) and no sync on green signal (f11), no component video input signal (f12) and no analog RGB input signal (f13) are set. To do. The determination means is performed every several 100 ms, and the state is constantly updated.

  For S-video input, the function of determining whether or not the YC signal of the video decoder 10 is input is monitored every several 100 ms, and the result is used.

  Similarly to the S video input, the composite video input is monitored every several hundreds ms for the function of determining whether or not the composite video signal of the video decoder 10 is input, and the result is used.

  As described above, by correctly discriminating between the analog RGB signal and the component signal input from the common terminal, it is possible to detect the presence or absence of the synchronization signal regardless of which input is selected. As a result, the user can recognize which input can be displayed without a selection switching operation, and can easily switch to a desired input.

  In this embodiment, the D-Sub 15-pin terminal 3 is used for analog input. However, even if the DVI terminal 2 is configured to accept analog input at the DVI-I terminal, it can be processed in the same way. However, when processing the synchronization signal separation unit 8 alone, the synchronization signal separation unit 8 needs to have two or more horizontal and vertical synchronization signal inputs and two sync-on-green signal inputs. In addition, the synchronization signal section and the frequency measurement section must also have two inputs for selection and non-selection inputs, respectively.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

It is a block block diagram of the projection type display apparatus of a 1st Example. It is a figure which shows the example of an input selection menu concerning a 1st Example. It is a figure which shows the example of a signal timing list which concerns on a 1st Example. It is a flowchart of the component video input and analog RGB input discrimination method according to the first embodiment. 4 is a flowchart of a VGA01 and 480p discrimination method according to the first embodiment. It is a block block diagram of the projection type display apparatus which concerns on a 2nd Example. It is a figure which shows the example of an input selection menu concerning a 2nd Example. It is a flowchart of the component video input and analog RGB input discrimination method according to the second embodiment. It is a figure which shows the example of the conventional input selection menu.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control part 2 DVI terminal 3 D-Sub15 pin terminal 4 S video terminal 5 Composite video terminal 6 Key input part 7 TMDS receiver 8 Synchronization signal separation part 9 AD converter 10 Video decoder 11 Input signal processing part 12 Memory 13 Resolution conversion part 14 OSD processing unit 15 OSD memory unit 16 display unit 17 frequency measurement unit S1 TMDS signal S2 RGB signal S3 G, horizontal synchronization, vertical synchronization signal S4 horizontal synchronization, vertical synchronization signal S5 YC signal S6 composite signal S7 RGB digital, horizontal synchronization, vertical Sync signal S8 RGB digital, horizontal sync, vertical sync signal S9 YUV digital, horizontal sync, vertical sync signal

Claims (5)

  An input terminal capable of inputting different video signals, a synchronization signal separation unit for separating a synchronization signal in the video signal input to the input terminal, a frequency measurement unit for measuring the frequency of the synchronization signal, and the synchronization signal separation A display device comprising: an input signal discrimination unit for discriminating a video signal input to the input terminal from a type of the synchronization signal separated by the unit and a measurement result of the frequency measurement unit.   The display device according to claim 1, wherein the different video signals include an analog RGB signal and a component video signal.   It has a memory that stores the frequency of the synchronization signal corresponding to the standard of the analog RGB signal and the component video signal, and the input signal discrimination unit is a sync on green signal, the synchronization signal separated by the synchronization signal separation unit, 3. The display device according to claim 2, wherein when the measurement result of the frequency measurement unit matches a frequency corresponding to a standard of a component video signal stored in the memory, the input signal is determined as a component video signal. .   4. The apparatus according to claim 1, further comprising: a plurality of input terminals including input terminals through which the different video signals can be input, and periodically detecting presence / absence of an input video signal for each of the plurality of input terminals. Display device.   5. The display device according to claim 4, wherein a detection result of presence / absence of an input video signal for each of the plurality of input terminals is displayed.

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