JP2017016071A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device capable of preventing deterioration in the display quality of screen display by curbing luminance change on a screen.SOLUTION: An image display device 100 comprises: a display panel 114; a backlight 116 for lighting the display panel 114 from a rear; a communication data creation unit 120 for creating communication data to be an output object to the outside; a PWM signal generation unit 122 for generating a PWM signal which is for adjusting the luminance of the backlight 116 by PWM control and on which the communication data created by the communication data creation unit 120 is superposed; and a backlight driver 126 for driving the backlight 116 on the basis of the PWM signal generated by the PWM signal generation unit 122.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display apparatus in which brightness adjustment is performed using a backlight.

  Conventionally, when an abnormality in a signal input to the image display or an abnormality in the operation of the image display is detected, the brightness of a backlight included in the image display is changed, so that a complicated image such as a character is displayed. There is known a configuration capable of notifying abnormality using a screen display even when the drawing function is not provided (see, for example, Patent Document 1). Further, the entire display screen of the image display blinks in a manner corresponding to the type of abnormality, so that the user can know the occurrence of abnormality and the content of the abnormality.

JP 2011-150135 A

  By the way, in the image display device disclosed in Patent Document 1 described above, the brightness of the backlight is changed to notify the user of the presence / absence of the abnormality and the contents thereof, so that the normal screen is displayed in parallel with the abnormality notification. When performing display, there is a problem that display quality (visibility) of normal screen display is deteriorated due to a large change in luminance. In addition, the image display disclosed in Patent Document 1 is for reporting the occurrence of an abnormality to the user by a change in luminance. Therefore, the internal operation or the like of the image display in which no abnormality has occurred is debugged and the result is displayed. There has been a problem that it cannot be used to convey information to the user or to convey information different from the displayed content to the user.

  The present invention was created in view of these points, and its purpose is to prevent the display quality of the screen display from deteriorating by suppressing the change in screen brightness when the internal state or the like is transmitted to the outside. An object of the present invention is to provide an image display device capable of performing the above. Another object of the present invention is to debug the internal operation of the image display regardless of whether or not an abnormality has occurred and to inform the user of the result, or to use it for transmitting information other than the display content to the user. An object of the present invention is to provide an image display device capable of performing the above.

  In order to solve the above-described problems, an image display device of the present invention includes a display panel, a backlight that illuminates the display panel from the back, communication data generation means that generates communication data to be output to the outside, and a backlight. A PWM signal for adjusting the brightness of the light by PWM control, which is generated by the PWM signal generation unit, and a PWM signal generation unit that generates a PWM signal on which the communication data generated by the communication data generation unit is superimposed. Backlight driving means for driving the backlight based on the PWM signal. In addition, it is desirable that the PWM signal generation unit described above superimposes the communication data corresponding to the lighting period in the PWM signal. Furthermore, the display panel described above is preferably a liquid crystal display panel.

  Since the communication data is superimposed on the PWM signal used to set the brightness of the backlight combined with the display panel by PWM control, when transmitting the internal state etc. to the outside, the screen can be visually confirmed. It is possible to prevent the display quality of the screen display from being deteriorated without greatly changing the luminance.

  In addition, it is preferable to further include a duty correction unit that adjusts the duty change due to the communication data superimposed on the PWM signal and corrects the duty change to the same as the PWM signal before the communication data is superimposed. Thereby, it becomes possible to maintain the brightness | luminance of a backlight constant.

  Further, the PWM signal generation means described above superimposes communication data corresponding to the lighting period in the PWM signal, and the duty correction means turns off by the duty reduction due to the communication data superimposed corresponding to the lighting period in the PWM signal. It is desirable to perform correction so as to shorten the period. As a result, it is possible to secure a certain luminance by correcting a decrease in luminance of the backlight caused by superimposing communication data.

  Further, the apparatus further includes abnormality detection means for detecting an abnormality of each part included in the image display device described above, and the communication data creation means determines at least one of the presence / absence, content, and abnormality occurrence location of the abnormality detected by the abnormality detection means. It is desirable to create communication data including. Accordingly, when an abnormality occurs in any part included in the image display device, it is possible to convey information regarding the abnormality to the outside without affecting the display content at that time.

  In addition, it is preferable that debugging means for debugging the operation of each unit included in the image display device described above is further provided, and the communication data creation means creates communication data including information obtained by debugging by the debugging means. As a result, the result of debugging any part included in the image display device can be transmitted to the outside without affecting the display contents at that time.

  Further, it is mounted on the vehicle, and the display panel displays information related to the traveling of the vehicle, and the communication data creating means desirably creates communication data including the information related to the traveling. As a result, even when the display panel is broken and display becomes difficult, it is possible to convey information related to vehicle travel (for example, speed information) to the outside, and the user such as the driver can communicate the contents. It becomes possible to confirm.

It is a figure which shows the structure of the image display apparatus of one Embodiment. It is a figure which shows the PWM signal waveform at the time of carrying out PWM control of the backlight. It is a figure which shows an example of the communication data reader which reads the communication data superimposed on the illumination using a backlight outside the image display apparatus.

  Hereinafter, an image display apparatus according to an embodiment to which the present invention is applied will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of an image display apparatus according to an embodiment. An image display device 100 shown in FIG. 1 is incorporated in, for example, a head unit mounted on a vehicle, and displays an image based on a video signal output from a head unit main body (not shown). The position of the user's fingertip or the like detected by is output to the head unit body.

  The image display apparatus 100 includes a transceiver 110, a display driver 112, a display panel 114, a backlight 116, a touch panel 118, a communication data creation unit 120, a PWM signal generation unit 122, a duty correction unit 124, a backlight driver 126, and an abnormality detection unit 130. , A debug processing unit 132, a power supply circuit 140, and a control unit 150.

  The transceiver 110 converts an LVDS (Low Voltage Differential Signaling) format video signal input from the head unit main body via a video input terminal into an RGB format video signal. The display driver 112 drives the display panel 114 based on the RGB format video signal, and displays an image indicated by the video signal. The display panel 114 is a color liquid crystal panel, for example, and is assembled in a state facing the backlight 116 that illuminates from the back. The backlight 116 is formed by, for example, an LED, but other light sources may be used.

  The touch panel 118 is arranged so as to overlap the surface of the display panel 114, and detects the position on the screen where the user's finger or the like has come into contact. As this touch panel 118, for example, a capacitive touch panel is used, but a touch panel of another type (resistance film type or the like) may be used.

  The communication data creation unit 120 creates communication data to be output to the outside of the image display device 100. A specific example of this communication data will be described later. The PWM signal generation unit 122 is a PWM signal for adjusting the luminance of the backlight 116 by PWM (Pulse Width Modulation) control, and the communication data generated by the communication data generation unit 120 is superimposed on the PWM signal. A PWM signal is generated.

  The duty correction unit 124 adjusts the duty change due to the communication data superimposed on the PWM signal and corrects it to the same duty as the PWM signal before the communication data is superimposed. For example, in the present embodiment, it is assumed that communication data is superimposed corresponding to the lighting period (ON period) in the PWM signal, and the duty correction unit 124 is superimposed corresponding to the lighting period in the PWM signal. Correction is performed so that the turn-off period is shortened by the amount of duty reduction due to the communication data. In the PWM signal generation unit 122 described above, the duty correction unit 124 generates a PWM signal taking the correction result into consideration. The backlight driver 126 performs PWM control based on the PWM signal generated by the PWM signal generation unit 122 to drive the backlight 116.

  The abnormality detection unit 130 detects an abnormality in each unit included in the image display device 100. The communication data creation unit 120 described above creates communication data including at least one of the presence / absence of an abnormality detected by the abnormality detection unit 130, the content of the abnormality, and the location where the abnormality has occurred.

  The debug processing unit 132 debugs the operation of each unit included in the image display device 100. For example, the debug processing unit 132 monitors a signal input / output from a configuration to be debugged (for example, the control unit 150), and creates information indicating the monitoring result. The communication data creation unit 120 described above creates communication data including information obtained by debugging by the debug processing unit 132.

  The power supply circuit 140 is connected to a battery (not shown) via a battery terminal BATT, and supplies operating power to each part of the image display device 100.

  The control unit 150 controls the entire image display apparatus 100. The control unit 150 is connected to the head unit main body via a communication terminal C, and transmits and receives various data to and from the head unit main body by communication according to, for example, a CAN (Controller Area Network) protocol. For example, when the user instructs to change the brightness of the display screen using the operation unit (not shown) of the head unit main body, the instruction is sent to the control unit 150 via the communication terminal C. The control unit 150 changes the duty of the PWM signal so that the luminance of the backlight 116 according to this instruction is obtained. In addition, the control unit 150 uses the touch panel 118 to monitor whether or not the user's finger or the like is in contact, detects the position when the finger or the like is in contact, and transmits information indicating the detected position to the communication terminal. Transmit to the head unit body via C.

  The communication data creation unit 120 described above is a communication data creation unit, the PWM signal generation unit 122 is a PWM signal generation unit, the backlight driver 126 is a backlight drive unit, the duty correction unit 124 is a duty correction unit, and an abnormality detection unit. Reference numeral 130 corresponds to the abnormality detection unit, and the debug processing unit 132 corresponds to the debug unit.

  The image display apparatus 100 of the present embodiment has such a configuration. Next, an operation for transmitting communication data to the outside in parallel with a normal image display operation will be described.

  FIG. 2 is a diagram showing a PWM signal waveform when the backlight 116 is PWM-controlled. In FIG. 2, “PWM (no communication data)” indicates the waveform of the PWM signal before the communication data created by the communication data creation unit 120 is superimposed on the lighting period (on period). For example, it is assumed that PWM control of the backlight 116 is performed using a 150 Hz PWM signal. The luminance of the backlight 116 is adjusted by changing the duty of the PWM signal.

  “Communication data” indicates a specific example of communication data created by the communication data creation unit 120. For example, if a communication speed of about 9600 to 4 Mbps is ensured, the minimum pulse width is about 20 μs to 50 ns, and a plurality of bits of communication data can be assigned to the PWM signal lighting period. In the example shown in FIG. 2, the communication data included in the A group and the communication data included in the B group are illustrated separately. However, the communication data creation unit 120 performs a series of communication between the A group and the B group. When data is generated and superimposed on the lighting period of the PWM signal by the PWM signal generation unit 122, the amount of data that can be assigned is determined according to the length of the lighting period, and is divided into A group and B group.

  “PWM (with communication data)” is obtained by superimposing the communication data of the A group and B group indicated by “communication data” on the PWM signal indicated by “PWM (no communication data)”. The waveform of the PWM signal is shown.

  “PWM (after correction)” has an extinguishing period corresponding to the duty reduction due to communication data superimposed on the PWM signal corresponding to the lighting period in the PWM signal indicated by “PWM signal (with communication data)”. The waveform of the PWM signal after correcting so as to be shorter is shown.

  In the present embodiment, by performing PWM control of the backlight 116 using the PWM signal indicated by “PWM (after correction)” in FIG. 2, communication data can be superimposed on illumination using the backlight 116.

  FIG. 3 is a diagram illustrating an example of a communication data reading device that reads communication data superimposed on illumination using the backlight 116 outside the image display device 100. 3 includes a light receiving unit 210, a communication data extracting unit 212, a data content determining unit 214, a display processing unit 216, and a display device 218.

  The light receiving unit 210 receives and detects illumination light of the backlight 116 output through the display panel 114 of the image display device 100. The detected light includes RGB information added by passing through the display panel 114. The communication data extraction unit 212 extracts communication data included in the light detected by the light receiving unit 210. As shown in FIG. 2, since the communication data to be extracted has a frequency higher than the frequency of the PWM signal, for example, by separating the high frequency component of the detection light, only the communication data is obtained. It becomes possible to extract. The data content determination unit 214 determines the content of the communication data extracted by the communication data extraction unit 212. As described above, the communication data includes the presence / absence of an abnormality, the content of the abnormality, the location where the abnormality occurred and information obtained by debugging (signals input / output from each unit), and the data content determination unit 214 These are separated and the presence or absence of abnormality indicated by each is determined. The display processing unit 216 displays the content determined by the data content determination unit 214 on the display device 218.

  By the way, the communication data reading device 200 described above can be realized by dedicated hardware, but may be realized by using a mobile terminal device such as a smart phone. For example, a camera provided in a mobile terminal device may be used as the light receiving unit 210 and the content of communication data may be displayed on a display device provided in the mobile terminal device. When the light emitted from the backlight 116 includes a component in the infrared region, communication data as an IrDA signal may be extracted using a terminal device having a light receiving unit according to the IrDA standard.

  As described above, in the image display apparatus 100 according to the present embodiment, the communication data is superimposed on the PWM signal used for setting the luminance of the backlight 116 combined with the display panel 114 by the PWM control. When the image is transmitted to the outside of the image display device 100, the brightness of the screen does not change so much as to affect the visibility, the display screen does not flicker as the brightness changes, and the display quality of the screen display is degraded. Can be prevented.

  Further, by superimposing communication data corresponding to the lighting period in the PWM signal, and correcting so that the extinguishing period is shortened by the duty reduction due to the communication data superimposed corresponding to the lighting period in the PWM signal, It is possible to secure a certain luminance by correcting the luminance reduction of the backlight 126 caused by superimposing the communication data.

  In addition, by detecting an abnormality of each unit included in the image display device 100 and creating communication data including at least one of the presence / absence of the detected abnormality, contents, and an abnormality occurrence location, the image display device 100 includes the communication data. When an abnormality occurs in any part, it is possible to convey information regarding the abnormality to the outside without affecting the display content at that time.

  Further, by creating communication data including information obtained by debugging, the result of debugging any part included in the image display apparatus 100 is transmitted to the outside without affecting the display contents at that time. It becomes possible.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, both the abnormality detection unit 130 and the debug processing unit 132 are provided, and communication data including information regarding both the occurrence of the abnormality and the debug is created, but one of the abnormality detection unit 130 and the debug processing unit 132 is created. Communication data including information corresponding to one of the occurrence of an abnormality and debugging may be created.

  Alternatively, communication data including other information may be created. For example, when information related to traveling of the vehicle is displayed on the display panel 114, the communication data creating unit 120 may create communication data including information related to traveling. When the image display device 100 attached to the front of the driver's seat displays vehicle speed, engine speed, and whether or not various warning lights are lit as information related to vehicle travel, data indicating these contents is displayed in the control unit 150. Considering the case of input, by creating communication data including this data, even if the display panel 114 breaks down and the vehicle speed or the like cannot be displayed, the vehicle speed, engine speed, etc. The image can be displayed on the display device 218 of the reading device 200. Thereby, even if the display panel 114 breaks down and display becomes difficult, the driver or the like can check the speed or the like. In addition, when information relating to vehicle travel is included in the communication data in this way, at least one of the above-described abnormality occurrence and debugging may be included in the communication data (or not included). May be)

  In the above-described embodiment, the duty correction unit 124 is used to adjust the duty change due to the communication data superimposed on the PWM signal so that the duty is corrected to the same duty as the PWM signal before the communication data is superimposed. However, a PWM signal (“PWM (with communication data)” shown in FIG. 2) that is not corrected by the duty correction unit 124 may be used. In this case, the luminance decreases according to the contents of the communication data, but the same effect (preventing deterioration of display quality of the screen display) can be obtained.

  In the above-described embodiment, the case where communication data is superimposed corresponding to the lighting period (ON period) in the PWM signal has been considered. However, the communication data is corresponding to the entire lighting period and extinguishing period of the PWM signal. You may make it superimpose. Also in this case, the luminance of the backlight 116 can be kept constant by correcting the duty of the PWM signal by the duty correction unit 124.

  As described above, according to the present invention, the communication data is superimposed on the PWM signal used for setting the luminance of the backlight combined with the display panel by the PWM control. In addition, the brightness of the screen does not change so much as can be visually confirmed, and the display quality of the screen display can be prevented from deteriorating.

DESCRIPTION OF SYMBOLS 100 Image display apparatus 110 Transceiver 112 Display driver 114 Display panel 116 Backlight 118 Touch panel 120 Communication data creation part 122 PWM signal generation part 124 Duty correction part 126 Backlight driver 130 Abnormality detection part 132 Debug processing part 140 Power supply circuit 150 Control part

Claims (8)

A display panel;
A backlight for illuminating the display panel from the back;
Communication data creation means for creating communication data to be output to the outside;
PWM signal generating means for generating a PWM signal for adjusting the brightness of the backlight by PWM control, wherein the communication data generated by the communication data generating means is superimposed;
Backlight driving means for driving the backlight based on the PWM signal generated by the PWM signal generating means;
An image display device comprising: In claim 1,
An image display apparatus, further comprising: a duty correction unit that adjusts a duty change due to the communication data superimposed on the PWM signal and corrects the duty change to be the same as that of the PWM signal before the communication data is superimposed. . In claim 1 or 2,
The PWM signal generation unit superimposes the communication data corresponding to a lighting period in the PWM signal. In claim 2,
The PWM signal generating means superimposes the communication data corresponding to a lighting period in the PWM signal,
The image display apparatus according to claim 1, wherein the duty correction unit performs correction so that a light extinction period is shortened by a duty reduction by the communication data superimposed corresponding to the lighting period in the PWM signal. In any one of Claims 1-4,
Further comprising an abnormality detection means for detecting an abnormality of each part included in the image display device
The image display apparatus, wherein the communication data creation means creates the communication data including at least one of the presence / absence of an abnormality detected by the abnormality detection means, contents, and an abnormality occurrence location. In any one of Claims 1-5,
A debugging means for debugging the operation of each unit included in the image display device;
The image display device, wherein the communication data creating means creates the communication data including information obtained by debugging by the debugging means. In any one of Claims 1-6,
Mounted on the vehicle,
The display panel displays information related to vehicle travel,
The image display device, wherein the communication data creating means creates the communication data including information relating to the traveling. In any one of Claims 1-7,
The image display device, wherein the display panel is a liquid crystal display panel.

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