JP2010008451A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: there is the case that a two-dimensional bar code displayed at a display device cannot be read well when reading it. <P>SOLUTION: The display device includes: a detection part for detecting the necessity of the output of a two-dimensional bar code; a generation part for generating the two-dimensional bar code to be output when it is detected by the detection part that it is needed to output the two-dimensional bar code; a display panel for displaying the two-dimensional bar code; and a back light installed on the back surface of the display panel, for providing the display panel with light. The generation part generates the plurality of two-dimensional bar codes comprising the integer multiple of pixels configuring the display panel by the same data configuration and displays the plurality of two-dimensional bar codes on the same screen on the display panel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device. In particular, the present invention relates to a two-dimensional barcode display method in a large-sized, high-definition, color-display liquid crystal display device such as a liquid crystal television.

  Many electronic devices have a self-diagnosis function for diagnosing the occurrence of a failure of the device, and have a transmission means for notifying the user of the failure of the device itself. As a simple transmission means, one that lights or blinks a pilot lamp is known. As another transmission means, for example, a three-digit error code is displayed, and the summary of the failure can be grasped by comparing the number with an instruction manual. As a further developed transmission means, when an electronic device has an image display or printing function, one utilizing the function is known.

  For example, the printing apparatus disclosed in Patent Document 1 prints or displays the occurrence of a failure of the device as, for example, a two-dimensional barcode (QR code) described in Patent Document 2 to facilitate maintenance. is there. Such a configuration is particularly effective for a variety of failures that may occur with the recent increase in functionality of electronic devices.

  Also, a means for reading a two-dimensional barcode has penetrated into life due to the spread of mobile phones having a two-dimensional barcode reading function. For this reason, not only the transmission of failure occurrence in electronic devices, but also the number of scenes in which a two-dimensional barcode is displayed as display content on a television broadcast or a personal computer screen has increased.

  In the present specification, the above-described QR code, which is generally widely used as a two-dimensional bar code, will be described below assuming a mobile phone as a reading device, but the present invention is not limited to this. .

  Here, the two-dimensional barcode and the reading device will be briefly described. First, a two-dimensional barcode will be described. FIG. 10 is a diagram showing an example of an overview of a two-dimensional barcode. FIG. 10A shows a positioning symbol for setting the reading position. The positioning symbol can be easily detected because the frequency component ratio of white and black (bright and dark) is constant in a line passing through the center when viewed from any direction. Next, FIG. 10B is a data area, and since this part is two-dimensional, it is characterized in that it can contain a lot of information. The size is determined from the capacity of information to be included in the two-dimensional barcode and the level of the required error correction rate. FIG. 10C is included in the data area, but is called a timing cell, and white and black cells (dots constituting a two-dimensional barcode) are always arranged alternately. With this rule, the coordinates of the two-dimensional code can be determined. Further, in FIG. 10D, a margin of 4 cells or more is to be taken in the margin area.

  Next, the two-dimensional barcode reading apparatus will be described. In recent years, mobile phones with cameras, which have become widespread in recent years, had about 300,000 pixels at the beginning, but now they have high resolution comparable to that of digital cameras, such as 3.2 million pixels. Suitable for reading applications.

  A CCD or CMOS is used as the sensor, and the pixel structure of the sensor has the RGB arrangement shown in FIG. 11A or the Bayer type arrangement shown in FIG. As for the optical system such as a lens that guides light to the sensor unit, it must be housed in a thin casing, and there are some things that cannot be said to be high performance due to intense cost competition.

Since it is originally a communication device, it greatly contributes to the role of connecting a two-dimensional barcode to a network, such as accessing a specific web page based on the read two-dimensional barcode information. On the other hand, as described above, the characteristics of the optical system such as resolution, pixel arrangement, and lenses are various and are not unified.
JP 2007-041840 A Japanese Patent No. 2938338

  In a liquid crystal display device, particularly a large-sized, high-definition, color display liquid crystal display device, when a two-dimensional bar code is displayed on a screen and an attempt is made to read it, a specific problem may occur. There were some backgrounds when liquid crystal display devices (liquid crystal televisions, personal computer liquid crystal monitors) were not yet common when 2D barcodes were devised, but 2D barcodes were originally supposed to be used as printed materials. I came. Accordingly, the liquid crystal display device has disadvantages in the following two points due to the characteristics of the display principle.

  A feature of the first display principle is that a color liquid crystal display device generally has a matrix-like structure with an RGB arrangement (trio arrangement). FIG. 12A shows an enlarged screen of the liquid crystal display device. FIG. 12A shows only horizontal 6 × vertical 2 pixels for the sake of space. The display of FIG. 12A is in the form of stripes of lighting (white), non-lighting (black), lighting (white), lighting (white), non-lighting (black), lighting (white) in order from the left pixel. To do. That is, the brightness desired to be expressed by the liquid crystal display device is as shown in FIG. As shown in FIG. 12A, in the liquid crystal display device, R, G, and B sub-pixels are combined to form one pixel.

  Further, between the R, G, and B sub-pixels, there is a so-called “joint” called a black matrix as shown in FIG.

  Of course, there is no problem when viewing directly from a standard viewing distance with the naked eye. This is because the resolution of the human eye is coarser than the resolution (one pixel) of the liquid crystal display device, so that a color such as white, which is a result of mixing R, G, and B at a pixel location, can be recognized.

  In order to explain this situation, the actual brightness distribution along the line (h) in FIG. 12 (a) is shown in FIG. 12 (c). The ratio of brightness (luminance) is approximately R: G: B = 3: 6: 1. Since the resolution is low with human eyes, it is recognized as if a low-pass filter has been applied as shown in FIG.

  However, unlike the human eye, the reader is very high definition. Based on the fact that the reading device has a color pixel arrangement as described above, the sampling points when the line (h) in FIG. 12A is read are shown in FIG. The distribution of the length is shown in FIG. The sampling points in FIG. 12 (e) can change as the reading magnification changes depending on the distance to the subject, but are arbitrarily set here.

  FIG. 12F is different from the brightness FIG. 12B to be displayed on the liquid crystal display device. This is a result of interference between the pixel arrangement of the liquid crystal display device and the pixel arrangement of the reading device. For example, if the G subpixel of the liquid crystal display device is captured by the G pixel of the reading device, the reading device determines that the portion is bright. However, if the B subpixel of the liquid crystal display device is captured by the G pixel of the reading device, it is determined that the portion is not very bright. This phenomenon is generally called moire (interference fringes).

  Although not reflected in FIGS. 12E and 12F for the sake of simplicity, the resolution differs between the central portion and the peripheral portion of the reading apparatus or due to the convenience of the lens and the optical system. There is a tendency to become darker, which acts in a worse direction as a factor of generation of moire and reading stability.

  There are mainly two known countermeasures against the occurrence of such moire. There is a measure for lowering the resolution of the reading device, and conversely a measure for performing image processing after increasing the resolution and reading in detail.

  The former prevents the occurrence of moiré by making the subject pattern (here, the pixels of the liquid crystal display device) sufficiently smaller than the resolution of the reading device and making the subject pattern unreadable. This is exactly the same as the human eye, but due to the fact that the actual resolution drop is different between the central part and the peripheral part of the reading device and the influence of the positional relationship (angle) between the liquid crystal display device and the reading device, Moire remains locally and does not lead to stable reading.

  Although the latter requires signal processing such as filtering, it is suitable for achieving the purpose of accurately reading a two-dimensional barcode. However, it is not the case that the latter measure can be realized in many cases. This is because increasing the resolution usually results in reading closer to the subject, but the specifications of the reading device are various as described above. In the case of the configuration, since the focus is lost due to the approach to the subject, it falls to the end.

  As described above, the white display of the liquid crystal display device is composed of a combination of R, G, and B sub-pixels, which is different from the uniform white of the printed matter, and that moire occurs depending on the specifications of the reading device. In addition, reading a two-dimensional barcode may be difficult.

  The feature of the second display principle is that many of the liquid crystal display devices blink at a cycle that cannot be seen by human eyes. The blinking cycle is approximately 60 to 300 hertz, and mainly occurs when the liquid crystal display device is dimmed.

  This is called so-called PWM dimming, and is repeatedly turned on and off alternately as shown in FIG. The liquid crystal display device is dimmed by controlling the lighting time ratio (duty ratio). In addition to PWM dimming, there is also a dimming method called “current dimming” in which the current value supplied to the light source is adjusted by lowering the voltage of the light source, but PWM dimming has a dimming range. Since it can be widely used and can be realized with a simple circuit configuration, it is widely applied.

  Due to the PWM dimming, there may be a difference in the brightness of the subject between the moment when the reading device detects the brightness of the subject and the moment when the reading is actually performed.

  As a countermeasure against this, it is known that a long shutter time is set so that a sufficiently large number of blinks are included in the shutter time. However, when the reading apparatus has a simple configuration, there may be no means for adjusting the shutter time. When the shutter time is increased, it is necessary to attach an ND filter in order to avoid an excessive amount of light. In general, it is difficult to implement.

  Under the condition where the shutter time cannot be set, it is finally possible to achieve the purpose by trying to read several times. In this specification, setting the lighting time ratio to 100% as shown in FIG. 13A is defined as “stopping the PWM dimming control”.

  In solving this problem, the liquid crystal display device of the present invention displays a plurality of two-dimensional barcodes having different sizes or error correction rates when displaying the two-dimensional barcode. Further, the PWM dimming control is stopped as necessary.

  A liquid crystal display device that can easily read a two-dimensional barcode can be provided.

The present invention will be described below with reference to the drawings.
(Embodiment 1)
A block diagram of a liquid crystal display device according to the first invention is shown in FIG. The failure detection unit 104 detects a failure that occurs in the liquid crystal display device and outputs a determination result. The failure image generation unit 106 generates a failure image (described later) to be displayed when a failure occurs based on the determination result of the failure detection unit 104.

  Based on the determination result output from the failure detection unit 104, the image control unit 105 determines whether an image to be displayed on the liquid crystal display device is an input video signal of the liquid crystal display device or an image generated by the failure image generation unit 106. Switch.

  Here, an image generated by the failure image generation unit 106 will be described. FIG. 2 is an example of a failure image. The area (a) in FIG. 2 informs the occurrence of a failure by text and is often implemented in a conventional liquid crystal display device. In the area of FIG. 2B, a two-dimensional barcode is displayed.

  Here, a feature of the present invention is that a plurality of two-dimensional barcodes having the same contents are simultaneously displayed in different sizes. Displaying one cell of a two-dimensional barcode with one pixel of a liquid crystal display device displays 1 ×, displaying one cell of a two-dimensional barcode with two pixels of a liquid crystal display device displays twice, and more than three times The same shall apply.

  For example, FIG. 2 (c) displays 4 times, FIG. 2 (d) displays 6 times, and FIG. 2 (e) displays 8 times. In general, a liquid crystal display device has a very high definition, and such an embodiment is possible. Of these, the user only has to read a two-dimensional barcode having a size that is most easily readable by the reading device he / she is holding.

  As in this example, the enlargement ratio is preferably an integral multiple. If there are less than a decimal, the cell of the two-dimensional barcode will be located across the pixels of the liquid crystal display device, and will be rounded up, rounded up, or filtered, and even the same one cell in the two-dimensional barcode will be thick This is because display / thin display, dark display / light display are mixed, and reading becomes unstable.

  FIG. 2 (f) explains that the arrangement for restoring the failure of the liquid crystal display device can be started by a two-dimensional barcode. The result of reading any two-dimensional barcode in FIG. 2B is as shown in FIG. 3, and is displayed on the display screen of the reading device.

  The underlined portion is a so-called “link”, and it is possible to select and implement measures such as making a call, sending an e-mail, or referring to a web page. Which correspondence is possible depends on the specifications of the reader.

With such a configuration, it is possible to read a two-dimensional bar code that matches the resolution of the reading device, and thus the above-described moire problem can be solved.
(Embodiment 2)
The liquid crystal display device according to the second invention will be described. Only the parts different from the first embodiment will be described.

  FIG. 4 is an image generated by the failure image generation unit 106. The area displaying the two-dimensional barcode in FIG. 4B is different from that in FIG. 4 (c), 4 (d), and 4 (e) change the error correction rate of the two-dimensional barcode described above.

  By changing the error correction rate, the size (called a version) of the two-dimensional barcode may change somewhat. As a result of increasing the error correction rate because the reader wants stable reading, the size of the two-dimensional bar code becomes large. As a result, if the reading device cannot read the data, it will fall.

  The user only needs to read the two-dimensional bar code that is most easily read by the reading device in FIG. 4B.

In this example, a two-dimensional bar code in which only the error correction rate is changed is displayed. However, there are two size differences as in the first embodiment, two error correction rate differences, and four in total. It may be combined such as displaying.
(Embodiment 3)
A liquid crystal display device according to the third invention will be described. Only portions different from the first and second embodiments will be described.

  5 (m) and 5 (n) are images in which the failure image generation 106 occurs. The two types of images shown in FIGS. 5 (m) and 5 (n) are switched and displayed at a certain time, for example, 20 seconds.

  Many types of two-dimensional barcodes can be considered with the size difference, the error correction rate difference, and the combination shown in the first embodiment and the second embodiment, but the liquid crystal display device has a high definition, There is a limit to displaying them all at the same time. Therefore, it is a feature of this embodiment that the necessary two-dimensional barcode is displayed in a plurality of times.

  The display switching time (cycle) may be determined on the assumption that the display is not frequently switched during reading and that the user can understand that a plurality of images are displayed.

(Embodiment 4)
A block diagram of a liquid crystal display device according to the fourth invention is shown in FIG. Only portions different from the first to third embodiments will be described. Compared to the block diagram of FIG. 1, a dimming control unit 607 is added.

  Based on the determination result of the failure detection unit 104, the dimming control unit 607 controls the backlight 103 to follow the dimming input set by the user or to stop the PWM dimming control. Usually, when there is no failure in the liquid crystal display device, dimming is performed according to the dimming input that is set so that the user can easily see (FIGS. 7A and 7B), and the failure occurs. When the fault image as shown in FIG. 2 is displayed, the PWM dimming control is stopped (FIG. 7C).

  In this way, when a failure occurs, a two-dimensional barcode is displayed, and the reader can easily display the two-dimensional barcode during a period when the user is expected to read the two-dimensional barcode with the reader. Can be read.

  As another means, the PWM dimming control is stopped only in the area where the two-dimensional bar code is output, and the dimming control is performed for the other screen areas according to the dimming input set by the user. Is possible. With such a configuration, it is not necessary to consider blinking in a period that is not understood by the human eye in the area of the two-dimensional barcode, and the two-dimensional barcode can be appropriately read. In this area, it is possible to provide an image by dimming control preferred by the user.

(Embodiment 5)
A block diagram of a liquid crystal display device according to the fifth invention is shown in FIG. Only portions different from the first to fourth embodiments will be described. In the present embodiment, the liquid crystal display device has a “two-dimensional barcode reading mode”. Compared to FIG. 6, a two-dimensional barcode mode reading button 808 is added, and the function of the dimming control unit 807 is changed.

  The dimming control unit 807 follows the dimming input set by the user based on whether or not the two-dimensional barcode mode reading button 808 is pressed by the user in addition to the determination result of the failure detection unit 104, The backlight 103 is controlled to stop the control.

  FIG. 9 shows how the backlight 103 is controlled.

  Usually, when there is no failure in the liquid crystal display device, dimming is performed so that the user can easily see (FIGS. 9A and 9B), and the failure occurs, as shown in FIG. When displaying a fault image, the PWM dimming control is stopped (FIG. 9C), and the two-dimensional barcode reading mode button 808 is pressed by the user, and the “two-dimensional barcode reading mode” is set. Even when it is turned on, the PWM dimming control is stopped (FIG. 9C).

  Such control assumes a situation in which a two-dimensional barcode is displayed on a display content such as a television broadcast or a web page in addition to when a failure of the apparatus occurs, and the user reads the two-dimensional barcode and is stable. The purpose is to read 2D barcodes.

  As another means, the PWM dimming control is stopped only in the area where the two-dimensional bar code is output, and the dimming control is performed for the other screen areas according to the dimming input set by the user. Is possible. With such a configuration, it is not necessary to consider blinking in a period that is not understood by the human eye in the area of the two-dimensional barcode, and the two-dimensional barcode can be appropriately read. In this area, it is possible to provide an image by dimming control preferred by the user.

  Note that although a liquid crystal display device is described in this embodiment mode, the present invention is not limited to this, and can be applied to other display devices.

  In the present embodiment, the description has been divided into the first to fifth embodiments, but the present invention can also be used simultaneously as appropriate.

  In the present embodiment, the case of detecting a failure has been described. However, the present invention is not limited to this, and can be applied to all cases in which a two-dimensional barcode is displayed on a screen. In this case, the failure detection unit can be a two-dimensional barcode detection unit (or simply detection unit), and the failure image generation unit can be a two-dimensional barcode generation unit (or simply generation unit, generation). Part).

    The liquid crystal display device of the present invention facilitates reading of a two-dimensional bar code with a simple configuration, and can be used for recovery of a failure of the liquid crystal display device.

1 is a block diagram of a liquid crystal display device according to a first embodiment. Diagram showing an example of a failure image The figure which shows the example of the reading result of a two-dimensional barcode Diagram showing an example of a failure image Diagram showing an example of a failure image The block diagram of the liquid crystal display device as described in 4th Embodiment Illustration of PWM dimming control The block diagram of the liquid crystal display device as described in 5th Embodiment Illustration of PWM dimming control Illustration of 2D barcode Explanatory drawing of pixel structure of sensor of reading device Diagram of pixel structure and brightness distribution of liquid crystal display device Illustration of PWM dimming control

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Liquid crystal display device 102 Liquid crystal panel 103 Backlight 104 Fault detection part 105 Image control part 106 Fault image generation part 607,807 Light control part 808 Two-dimensional barcode reading mode button

Claims (8)

A display device that displays a plurality of two-dimensional barcodes having different sizes when displaying a two-dimensional barcode. A display device that displays a plurality of two-dimensional barcodes having different error correction rates when displaying the two-dimensional barcode. A display device that displays a plurality of two-dimensional barcodes having different sizes or error correction rates when displaying a two-dimensional barcode. A display device characterized in that when a two-dimensional barcode is displayed, a screen on which a plurality of two-dimensional barcodes having different sizes or error correction rates are displayed is switched at a constant cycle. The display device according to any one of claims 1 to 4, wherein PWM dimming control is stopped when displaying a two-dimensional barcode. 6. The display device according to claim 1, wherein the PWM dimming control can be stopped by a user's intention. A display device capable of displaying a two-dimensional barcode on a screen,
A receiver for receiving the input video signal;
A detection unit for detecting the necessity of outputting a two-dimensional barcode;
A generation unit that generates a two-dimensional barcode to be output when the detection unit detects that a two-dimensional barcode needs to be output;
An image controller that selects and outputs the video signal received by the receiver or the two-dimensional barcode generated by the generator;
A display panel for displaying a video signal or a two-dimensional barcode selected by the image control unit;
A backlight that is installed on the back of the display panel and provides light to the display panel;
The generation unit generates a plurality of two-dimensional barcodes having the same data configuration and an integer multiple of pixels constituting the display panel, and displays the plurality of two-dimensional barcodes on the same screen on the display panel. A display device characterized by: 8. The display according to claim 7, wherein the backlight is PWM-driven, and the PWM drive is stopped only when the detection unit detects that the two-dimensional barcode needs to be output. apparatus.

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