WO2007049404A1

WO2007049404A1 - Communication device, communication system and communication method

Info

Publication number: WO2007049404A1
Application number: PCT/JP2006/318119
Authority: WO
Inventors: Yasuyuki Irie
Original assignee: Kyocera Corporation
Priority date: 2005-10-28
Filing date: 2006-09-13
Publication date: 2007-05-03
Also published as: JP4739914B2; JP2007124404A

Abstract

Provided are a communication device, a communication system and a communication method by which optical communication having high degree of freedom is made possible. A liquid crystal display as a transmitter is provided with a display section composed of a backlight unit (1) for displaying an imge, a polarization film (2), a TFT substrate (3) and a RGB filter (4); an emission control section (5) for contents, for permitting the display section to display an image corresponding to contents information in a first cycle; and an emission control section (6) for communication, for permitting the display section to display an image corresponding to the communication information in a second cycle , while the image corresponding to the contents information is not displayed on the display section.

Description

Specification

COMMUNICATION DEVICE, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

Technical field

TECHNICAL FIELD [0001] The present invention relates to a communication device, a communication system, and a communication method, and more particularly to a technique for performing communication using visible light.

Background art

[0002] Recently, wireless communication using light and radio waves is used in various fields! Since such wireless communication does not require a cable as a data transmission path, for example, mutual communication between devices such as mobile devices, personal computers (PCs), PDAs (Personal Digital Assistants), and PCs. It is used in various communications such as communication with peripheral devices such as printers and displays (see, for example, Patent Documents 1 and 2). In particular, optical communication is expected to expand the range of use in the future because it is cheaper than radio communication systems and is not affected by electromagnetic radiation noise.

[0003] As a conventional optical communication system, for example, there is a configuration in which a transmitter generates a pulse signal sequence or the like in which light intensity such as infrared rays is changed, and a receiver analyzes a pulse signal. In optical communication, a modulated signal by such light intensity modulation processing is often used.

[0004] In addition, when light in the visible light region is used for optical communication, the light is often used as illumination light at the same time. The light source has been proposed to realize white with RGB three-color LED and to use white LED! RU

[0005] Further, among devices having both the function of visible light communication and the function of illumination, two or more colors having complementary colors are combined to produce white light for illumination. Some have achieved multi-color communication using multiple colors of light.

[0006] Further, there is a method for realizing visible light communication by using a screen that emits light in a single color as a light source, and changing the color of the light source with time.

Patent Document 1: JP-A-10-190584

Patent Document 2: JP 2004-72365 A

Disclosure of the invention Problems to be solved by the invention

[0007] Currently, when multiple color communication in visible light communication is realized using a display device or the like, it is based on information generated in accordance with temporal changes in colors included in content displayed on the display device or the like. , Red (R), green (G), and blue (B) are determined so that the degree of freedom of information transmission is limited.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a communication device, a communication system, and a communication method capable of optical communication with a high degree of freedom. There is.

Means for solving the problem

[0009] The present invention relates to a display unit for displaying an image, content information image display control means for displaying an image corresponding to content information on the display unit in a first cycle, and content information to the display unit. Communication information image display control means for causing the display unit to display an image corresponding to the communication information in the second period while the image to be displayed is not displayed.

[0010] With this configuration, while an image corresponding to content information is not displayed on the display unit, an image corresponding to communication information is displayed, and communication is possible using the image light. Therefore, optical communication with a high degree of freedom without being affected by the image corresponding to the content information becomes possible.

[0011] In the communication device of the present invention, the second period may be equal to or less than the first period.

[0012] With this configuration, it is possible to make it difficult for a person viewing an image corresponding to content information to recognize that an image corresponding to communication information is included.

[0013] From the same viewpoint, in the communication device of the present invention, the second period is 360 Hz or less.

[0014] Further, in the communication device of the present invention, the display unit includes a plurality of light emitting units corresponding to a plurality of colors, and the communication information image display control unit performs the plurality of the plurality of light emitting units according to the communication information. You can also control the light emission order of the light emitting parts.

[0015] With this configuration, communication information can be represented by the light emission order of the plurality of light emitting units. [0016] Further, in the communication device of the present invention, the communication information image display control unit corresponds to the communication information on the display unit with the luminance of the image corresponding to the content information displayed on the display unit immediately before. Display the image you want to view.

[0017] With this configuration, it is more difficult to recognize that a person viewing an image corresponding to content information includes an image corresponding to communication information.

[0018] In addition, the present invention provides a light receiving unit that receives light of an image corresponding to content information and light of an image corresponding to communication information, and light of an image corresponding to content information received by the light receiving unit. Demodulating means for demodulating the communication information based on the light of the image corresponding to the communication information out of the light of the image corresponding to the communication information.

With this configuration, communication information can be obtained from light of an image corresponding to the communication information from the communication device described above.

[0020] Further, the communication device of the present invention has communication quality deriving means for deriving communication quality based on light corresponding to the communication information, and the demodulation means is regarded as having good communication quality. In some cases, the communication information may be demodulated.

[0021] This configuration prevents unnecessary demodulation.

[0022] Further, the communication device of the present invention may have a notification means for notifying the communication quality.

With this configuration, the user of the communication device can recognize the communication quality.

[0024] The present invention is a communication system including a communication device that displays an image corresponding to the communication information described above and a communication device that receives light of an image corresponding to the communication information.

[0025] Further, the present invention is a communication method in a communication apparatus having a display unit for displaying an image, and a content information image display control for displaying an image corresponding to content information on the display unit in a first cycle. And a communication information image display control step of causing the display unit to display an image corresponding to the communication information in a second period while an image corresponding to the content information is not displayed on the display unit.

The invention's effect

[0026] According to the present invention, while an image corresponding to the content information is displayed on the display unit, an image corresponding to the communication information is displayed and communication can be performed using the image light. Optical communication with a high degree of freedom without being affected by the image corresponding to the tenth information becomes possible.

Brief Description of Drawings

FIG. 1 is a diagram showing a configuration of a liquid crystal display as a transmitter.

FIG. 2 is a diagram showing a configuration of a part for controlling an RGB filter in a liquid crystal display.

FIG. 3 is a diagram showing two pixels corresponding to an RGB filter of a display unit in a liquid crystal display as a transmitter.

FIG. 4 is a diagram showing an example of transition of the light emission state of a pixel corresponding to communication information “0”.

FIG. 5 is a diagram showing an example of transition of the light emission state of a pixel corresponding to communication information “1”.

FIG. 6 is a diagram showing an example of transition of the light emission state of a pixel corresponding to communication information “00”.

FIG. 7 is an example of an image displayed on a display unit in a liquid crystal display.

FIG. 8 is a diagram showing an example of transition of the light emission state of a pixel corresponding to communication information “11”.

FIG. 9 is a diagram showing an operation during communication of the liquid crystal display.

FIG. 10 is a diagram showing an operation of the liquid crystal display during non-communication.

FIG. 11 is a diagram showing a configuration of a receiver.

FIG. 12 is a flowchart showing an operation at the time of reception by the receiver.

FIG. 13 is a flowchart showing the screen transition operation of the display unit in the receiver.

FIG. 14 is a diagram showing screen transition of the display unit in the receiver.

FIG. 15 is a diagram showing a correspondence relationship between the communication quality of visible light communication, the state of the display unit in the receiver, and the image displayed on the display unit.

FIG. 16 is a diagram illustrating an example of communication quality of visible light communication.

FIG. 17 is a diagram showing an example of image display on the display unit when the receiver is a mobile terminal.

BEST MODE FOR CARRYING OUT THE INVENTION

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

FIG. 1 is a diagram showing a configuration of a liquid crystal display which is a transmitter for visible light communication according to the present embodiment. This liquid crystal display is composed of backlight unit 1, polarizing film 2, TF It comprises a T substrate 3, an RGB filter 4, a content light emission control unit 5, a communication light emission control unit 6, a display communication control unit 7, a communication information storage unit 8, and a content information storage unit 9. Among these units, a display unit comprising a backlight unit 1, a polarizing film 2, a TFT substrate 3, and an RGB filter 4, a content light emission control unit 5, and a content information storage unit 9 are used for a normal liquid crystal display. Visible light communication can be realized by arranging the communication light emission control unit 6 and the communication information storage unit 8.

[0030] In addition to adding the communication light emission control unit 6 and the communication information storage unit 8 to the liquid crystal display, during the scan in which an image corresponding to content information such as a moving image or a still image is displayed. By inserting an image corresponding to the communication information into, it is possible to communicate with visible light while the image is displayed.

[0031] The part other than the display unit is divided into two parts: an image-related part and a communication-related part. A content information storage unit 9 which is a part related to an image stores content information. The content light emission control unit 5 displays an image corresponding to the content information on the display unit based on the content information input from the content information storage unit 9. On the other hand, the communication information storage unit 8 which is a part related to communication stores communication information. The communication light emission control unit 6 controls the backlight unit 1 based on the communication information input from the communication information storage unit 8 and causes the display unit to display an image corresponding to the communication information. The image corresponding to the communication information and the image corresponding to the content information are alternately displayed in time on the display unit.

[0032] During communication, the luminance of the image corresponding to the content information displayed on the display unit may or may not be reflected in the image corresponding to the communication information. When the brightness of the image corresponding to the content information displayed on the display unit is reflected in the image corresponding to the communication information, the communication information stored in the communication information storage unit 8 is input to the communication light emission control unit 6 and The content information stored in the content information storage unit 9 is input to the communication light emission control unit 6 via the display communication control unit 7. The communication light emission control unit 6 controls the backlight unit 1 based on the communication information and the content information, and causes the display unit to display an image corresponding to the communication information and the content.

[0033] On the other hand, the brightness of the image corresponding to the content information displayed on the display unit is an image for communication. If not reflected, only the communication information stored in the communication information storage unit 8 is input to the communication light emission control unit 6, and the communication light emission control unit 6 controls the backlight unit 1 with this communication information. Then, an image corresponding to the communication information is displayed on the display unit.

FIG. 2 is a diagram showing a configuration of a portion that controls the RGB filter 4 in the liquid crystal display. The configuration of the control part is as follows: red LED 10, green LED 11, blue LED 12 in RGB filter 4, arithmetic unit 13, control unit 14, timing generator 15, and communication information storage unit 8 in communication light emission control unit 6. It is composed of. The communication light emission control unit 6 inputs the communication information stored in the communication information storage unit 8 into the red LED 10, the green LED 11, and the blue LED 12. Then, the red LED 10, the green LED 11, and the blue LED 12 light up and blink according to the communication information sequence.

[0035] When the luminance of the image corresponding to the content information displayed on the display unit is reflected in the image corresponding to the communication information, when displaying the image corresponding to the communication information, the RGB filter corresponding to each pixel thereof 4 emits light while maintaining the brightness of the image corresponding to the content information displayed at the previous time only the LED of the image color corresponding to the communication information.

FIG. 3 is a diagram showing two pixels corresponding to the RGB filter 4. In FIG. 3, red (R), green (G), and blue (B) colors emit light with the same brightness, so that it appears white to the human eye. Of the two pixels, the left pixel 1 is a high luminance pixel, and the right pixel 2 is a low luminance pixel.

FIG. 4 is a diagram illustrating an example of transition of the light emission state of the pixel corresponding to the communication information “0”.

When transmitting the communication information “0”, the communication light emission control unit 6 expresses “0” by emitting light in the order of red (R) and green (G), and finally blue (B). Color correction is performed by emitting light. On the other hand, FIG. 5 is a diagram illustrating an example of transition of the light emission state of the pixel corresponding to the communication information “1”. When transmitting communication information “1”, the communication light emission control unit 6 expresses “1” by emitting light in the order of red (R) and blue (B), and finally displays green (G). Correct color by emitting light

FIG. 6 is a diagram illustrating an example of transition of the light emission state of the pixel corresponding to the communication information “00”.

The light emission control unit for communication 6 corresponds to the communication information for the pixel at the odd-numbered timing. Does not emit light. For this reason, the pixel emits light corresponding to the content information. on the other hand

The communication light-emission control unit 6 causes the pixel to emit red (R) at the luminance 4 of the image corresponding to the content information at the second timing. Next, in the fourth timing, the communication light-emission control unit 6 causes the pixel to emit green (G) with the luminance 3 of the image corresponding to the content information. Further, the communication light emission control unit 6 causes the pixel to emit light in blue (B) at the luminance 3 of the image corresponding to the content information at the sixth timing. In this way, red (R) emits light at the second timing, and green (G) emits light at the fourth timing, so that “0” is expressed, and blue (B ) Emits light, thereby realizing color correction.

FIG. 7 is an example of an image displayed on the display unit at timings 1 to 6 in FIG. As shown in FIG. 7, an image corresponding to the content information is displayed at the odd-numbered timing. On the other hand, the red (R) part of the image corresponding to the content information is displayed at the second timing, the green (G) part at the fourth timing, and the blue (B) part at the sixth timing. The

[0040] Returning again to FIG. Similarly, at the eighth timing, the communication light emission control unit 6 causes the pixel to emit red (R) with the luminance 2 of the image corresponding to the content information. Next, the communication light emission control unit 6 causes the pixel to emit light in green (G) at the luminance 1 of the image corresponding to the content information at the tenth timing. Further, the communication light emission control unit 6 causes the pixel to emit light in blue (B) at the luminance 1 of the image corresponding to the content information at the 12th timing. In this way, red (R) emits light at the 8th timing, green (G) emits light at the 10th timing, and “0” is represented, and blue (B) at the 12th timing. Color correction is realized by emitting light.

FIG. 8 is a diagram illustrating an example of transition of the light emission state of the pixel corresponding to the communication information “11”.

The communication light-emission control unit 6 does not cause the pixels to emit light corresponding to the communication information at odd-numbered timings. For this reason, the pixel emits light corresponding to the content information. On the other hand, at the second timing, the communication light emission control unit 6 causes the pixel to emit red (R) with the luminance 4 of the image corresponding to the content information. Next, in the fourth timing, the communication light emission control unit 6 causes the pixel to emit light in blue (B) with the luminance 3 of the image corresponding to the content information. Further, the communication light emission control unit 6 corresponds to the pixel content information at the sixth timing. Lights green (G) with image brightness 3. In this way, red (R) emits light at the second timing and blue (B) emits at the fourth timing, thereby expressing “1”, and green (G ) Emits light, thereby realizing color correction.

Similarly, the communication light emission control unit 6 causes the pixel to emit red (R) at the luminance 2 of the image corresponding to the content information at the eighth timing. Next, the communication light-emission control unit 6 causes the pixel to emit blue (B) at the luminance 1 of the image corresponding to the content information at the tenth timing. Further, the communication light emission control unit 6 causes the pixel to emit green (G) at the luminance 1 of the image corresponding to the content information at the 12th timing. In this way, red (R) emits light at the 8th timing, and blue (B) emits light at the 10th timing, so that “1” is expressed, and green (G) at the 12th timing. By emitting light, color correction is realized.

FIG. 9 is a diagram showing an operation during communication of a liquid crystal display as a transmitter. The content light emission control unit 5 reads content information from the content information storage unit 9 (S1), and performs signal processing for image display corresponding to the content information (S2). Further, the content light emission control unit 5 displays an image corresponding to the content information on the display unit in accordance with the processed signal (S3). Next, the communication light emission control unit 6 reads the communication information from the communication information storage unit 8 and also reads the content information from the content information storage unit 9 (S4), and performs signal processing for image display corresponding to the communication information. Perform (S5). Here, as described above, the brightness of the image corresponding to the communication information is adjusted to be the brightness of the image corresponding to the content information. Further, the communication light emission control unit 6 causes the display unit to display an image corresponding to the communication information based on the processed signal (S6).

In the operation of FIG. 9, the VSYNC scanning frequency is preferably 360 [Hz], which is six times the normal frequency. Therefore, the time required for the operations of S1 to S6 described above is 0.0027 [Sec]. During this time, the flicker effect prevents the human eye from feeling flickering in brightness and chromaticity.

On the other hand, FIG. 10 is a diagram showing an operation of the liquid crystal display as a transmitter during non-communication. During non-communication, only operations S101 to S103 corresponding to S1 to S3 in FIG. 9 are performed. The time required for the operation of S101 to S103 is the VSYNC scanning frequency. Corresponding to the force S60 [Hz], 0.166 [Sec] is preferable. During this time, the flicker effect prevents the human eye from feeling any flickering in brightness or chromaticity.

FIG. 11 is a diagram showing a configuration of a visible light communication receiver according to the present embodiment. This receiver includes an optical filter 17 that allows red light to pass through, an optical filter 18 that allows green light to pass, and an optical filter that allows blue light to pass, among light from the liquid crystal display as the transmitter described above. An optical sensor 20 such as a CMOS sensor corresponding to these optical filters 17, a synchronization detection circuit 21, a determination unit 22, an SZN measurement unit 24, a calculation unit 25, a communication information storage unit 26, and a display Part 27.

FIG. 12 is a flowchart showing the receiving operation of the receiver. Each optical sensor 20 receives light that has passed through the corresponding optical filter 17 and the like, detects the luminance of the light, and outputs a signal (luminance signal) corresponding to the luminance to the determination unit 22 (S21).

[0048] When the image corresponding to the communication information and the image corresponding to the content information are alternately displayed on the liquid crystal display, the synchronization detection circuit 21 is a luminance corresponding to the light of the image corresponding to the communication information. The timing at which the signal reaches the determiner 22 is detected (S22). The determination unit 22 detects a temporal difference in the luminance signal input from each optical sensor 20 at the timing detected by the synchronization detection circuit 21, and at a timing at which the temporal difference is eliminated, The luminance signal is output to the SZN measuring device 24 (S23).

[0049] The SZN measuring device 24 measures the communication quality (SZ N value) of visible light communication based on the input luminance signal, and outputs the luminance signal and the SZN value to the computing unit 25 (S24 ). The computing unit 25 determines whether or not the input SZN value is greater than or equal to a predetermined value (S25). When the SZN value is equal to or greater than the predetermined value, the calculation unit 25 also demodulates the communication information with the input luminance signal power (S26). The demodulated communication information is stored in the communication information storage unit 26. On the other hand, when the SZN value is less than the predetermined value, the calculation unit 25 does not demodulate the communication information from the input luminance signal (S27).

FIG. 13 is a flowchart showing the screen transition operation in the display unit 27 of the receiver. When the optical sensor 20 receives light, the display unit 27 displays the message “Recognized optical wireless communication signal. Do you want to capture information?” (See Fig. 14 (a)) (S31). Next, the calculation unit 25 determines whether or not the user has performed an information capturing operation (S32). [0051] When an information capturing operation is performed, reception processing by the calculation unit 25 is started (S33). Further, the calculation unit 25 determines whether or not the reception sensitivity is poor, in other words, whether or not the input SZN value is less than a predetermined value (S34). If the reception sensitivity is good, the reception processing by the calculation unit 25 is continued (S35), and when the reception processing is completed, the display unit 25 displays “Information has been captured.” (See Fig. 14 (b)) (S36).

[0052] On the other hand, if the reception sensitivity is poor, the reception processing by the calculation unit 25 is interrupted, and the display unit 25 displays "Reception sensitivity is not good. Do you want to import again?" (Fig. 14 (c) (See S37). Next, the display unit 27 determines whether or not an information capturing operation has been performed by the user (S38). If an information capturing operation has been performed, the operations after S31 are repeated.

FIG. 15 is a diagram illustrating a correspondence relationship between the communication quality of visible light communication, the state of the display unit 27, and the image displayed on the display unit 27. FIG. 16 is a diagram illustrating an example of communication quality of visible light communication.

[0054] When the communication quality of visible light communication based on the SZN value is good, the display unit 27 is always bright and displays a sign indicating that it is good. The communication quality of visible light communication is good when the brightness of red (R), green (G), and blue (B) is stable at a predetermined value or more, as shown in Fig. 16 (a). Indicates. In this case, the receiver can receive communication information stably. In addition, when the communication quality of visible light communication based on the SZN value is unstable, the display unit 27 displays a sign indicating that the transition between light and dark becomes intense and unstable. Visible light communication quality is unstable when the ratio of the luminance of red (R), green (G), and blue (B) changes over time as shown in Fig. 16 (b). Indicates. In this case, the receiver may stop receiving communication information on the way. In addition, when the communication quality of the visible light communication based on the SZN value is poor, the display unit 27 is always dark and displays a sign indicating that it is defective. Visible light communication quality is poor, as shown in Fig. 16 (c), although the red (R), green (G), and blue (B) brightness is stable. Indicates a case where it is not sufficient. In this case, the receiver may stop receiving communication information on the way.

FIG. 17 is a diagram illustrating an example of image display on the display unit 27 when the receiver is a portable terminal. FIG. 17A illustrates a case where the communication quality of visible light communication is good. 17 (b) is visible When the communication quality of optical communication is unstable, Fig. 17 (c) shows the case where the communication quality of visible light communication is poor. As shown in FIG. 17, the display unit 27 can display not only the communication quality of mobile phone communication but also the communication quality of visible light communication based on the SZN value. Thereby, the user can grasp the communication quality of visible light communication.

[0056] As described above, in this embodiment, the image corresponding to the content and the image corresponding to the communication information are alternately displayed on the display unit of the liquid crystal display which is the transmitter, thereby corresponding to the content information. Optical communication with a high degree of freedom without being affected by the image to be transmitted becomes possible. In addition, by preventing the brightness of the image corresponding to the content and the brightness of the image corresponding to the communication information from changing, an image corresponding to the communication information is included by the person viewing the image corresponding to the content information. Can be difficult to recognize.

Industrial applicability

As described above, the communication device, the communication system, and the communication method according to the present invention are capable of highly flexible communication and are useful as communication devices and the like.

Claims

The scope of the claims

[1] a display for displaying images;

Content information image display control means for displaying an image corresponding to the content information on the display unit in a first cycle;

Communication information image display control means for causing the display unit to display an image corresponding to the communication information in a second period while an image corresponding to the content information is not displayed on the display unit. Communication device.

[2] The communication device according to claim 1, wherein the second period is equal to or less than the first period.

[3] The communication device according to claim 2, wherein the second period is 360 Hz or less.

[4] The display unit includes a plurality of light emitting units corresponding to a plurality of colors,

The communication according to any one of claims 1 to 3, wherein the communication information image display control unit controls a light emission order of the plurality of light emitting units according to the communication information. apparatus.

[5] The communication information image display control means causes the display unit to display an image corresponding to the communication information with the luminance of the image corresponding to the content information displayed on the display unit immediately before. The communication device according to any one of claims 1 to 3.

[6] a light receiving means for receiving the light of the image corresponding to the content information and the light of the image corresponding to the communication information;

Demodulating means for demodulating the communication information based on the light of the image corresponding to the communication information out of the light of the image corresponding to the content information received by the light receiving means and the light of the image corresponding to the communication information; A communication apparatus comprising:

[7] Communication quality deriving means for deriving communication quality based on light corresponding to the communication information is provided.

7. The communication apparatus according to claim 6, wherein the demodulation means demodulates the communication information when the communication quality is considered to be good.

[8] According to claim 7, further comprising notifying means for notifying the communication quality The communication device described.

[9] A communication system including the communication device according to any one of claims 1 to 5 and the communication device according to any one of claims 6 to 8.

[10] A communication method in a communication device having a display unit for displaying an image,

A content information image display control step for displaying an image corresponding to the content information on the display unit in a first cycle;

A communication information image display control step for displaying an image corresponding to the communication information on the display unit in a second period while an image corresponding to the content information is not displayed on the display unit. Communication method.