Optical communication device and optical communication system

Abstract

Provided are an optical communication device and an optical communication system that make it possible to shorten the transmission time of Morse-coded information. The optical communication device comprises a light source, an optical element that is provided on the optical axis of the light source and controls the light distribution state of light emitted from the light source, and a processing circuit for performing light distribution control of the optical element. The processing circuit generates a character information code obtained by converting character information into Morse code, controls the light distribution state of the optical element to a first light distribution shape when transmitting the short point code "." of the character information code, and controls the light distribution state of the optical element to a second light distribution shape different from the first light distribution shape when transmitting the long point code "-" of the character information code.

Description

Optical communication device and optical communication system

[0001] The present invention relates to an optical communication device and an optical communication system.

[0002] Conventionally, communication methods using Morse code have been established. For example, a technique for transmitting Morse-coded information by controlling the blinking pattern of a light source has been disclosed (for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2007-174509

[0004] Morse code is a character code that is variable-length coded by combining short dots ("・") and long dots ("-"), and is generally transmitted as a pulse-width modulated (PWM) Morse code. For this reason, transmission times may be long depending on the amount of information in the coded string or sentence.

[0005] An object of the present invention is to provide an optical communication device and an optical communication system that can shorten the transmission time of Morse-coded information.

[0006] An optical communication device according to one aspect of the present disclosure includes a light source, an optical element disposed on an optical axis of the light source and controlling a light distribution state of light emitted from the light source, and a processing circuit that controls the light distribution state of the optical element, wherein the processing circuit generates a character information code by converting character information into Morse code, and controls the light distribution state of the optical element to a first light distribution shape when transmitting a short dot code of the character information code, and controls the light distribution state of the optical element to a second light distribution shape different from the first light distribution shape when transmitting a long dot code of the character information code.

[0007] An optical communication system according to one aspect of the present disclosure includes an optical communication device and a control device that transmits character information to the optical communication device, wherein the optical communication device includes a light source, an optical element that is arranged on the optical axis of the light source and controls the light distribution state of the light emitted from the light source, and a processing circuit that controls the light distribution of the optical element, wherein the processing circuit generates a character information code by converting the character information into Morse code, and controls the light distribution state of the optical element to a first light distribution shape when transmitting a short dot code of the character information code, and controls the light distribution state of the optical element to a second light distribution shape different from the first light distribution shape when transmitting a long dot code of the character information code.

[0008] FIG. 1A is a side view showing an example of an optical communication device according to an embodiment. FIG. 1B is a perspective view showing an example of an optical element according to an embodiment. FIG. 2 is a schematic plan view of a first substrate as viewed from the Dz direction. FIG. 3 is a schematic plan view of a second substrate as viewed from the Dz direction. FIG. 4 is a perspective view of a liquid crystal cell in which a first substrate and a second substrate are stacked in the Dz direction. FIG. 5 is a cross-sectional view taken along the line AA′ shown in FIG. 4. FIG. 6A is a diagram showing the alignment direction of an alignment film on a first substrate. FIG. 6B is a diagram showing the alignment direction of an alignment film on a second substrate. FIG. 7 is a diagram showing the layered structure of an optical element according to an embodiment. FIG. 8A is a conceptual diagram for explaining a change in the shape of light caused by an optical element according to an embodiment. FIG. 8B is a conceptual diagram for explaining a change in the shape of light caused by an optical element according to an embodiment. FIG. 8C is a conceptual diagram for explaining a change in the shape of light caused by an optical element according to an embodiment. FIG. 8D is a conceptual diagram for explaining a change in the shape of light caused by an optical element according to an embodiment. FIG. 9 is a conceptual diagram for conceptually explaining light distribution control by an optical communication device according to an embodiment. FIG. 10 is a diagram showing a schematic configuration of an optical communication system according to an embodiment. FIG. 11 is a block diagram showing an example of a control device according to the first embodiment. FIG. 12 is a block diagram showing an example of an optical communication device according to the first embodiment. FIG. 13A is a diagram showing a specific example of a first light distribution shape. FIG. 13B is a diagram showing a specific example of a second light distribution shape. FIG. 14 is a flowchart showing an example of information transmission processing in the optical communication system according to the first embodiment. FIG. 15 is a diagram showing a schematic configuration of an optical communication system according to the second embodiment. FIG. 16 is a block diagram showing an example of a receiving device according to the second embodiment. FIG. 17 is a flowchart showing an example of information transmission processing in the optical communication system according to the second embodiment. FIG. 18 is a diagram showing an example of header information. FIG. 19 is a sub-flowchart showing an example of header information transmission processing. FIG. 20A is a conceptual diagram explaining light distribution control timing in the header information transmission processing. FIG. 20B is a conceptual diagram explaining light distribution control timing in the header information transmission processing. FIG. 20C is a conceptual diagram explaining light distribution control timing in the header information transmission processing. FIG. 21 is a sub-flowchart showing an example of message transmission processing. FIG. 22A is a conceptual diagram explaining light distribution control timing in the message transmission processing.Fig. 22B is a conceptual diagram illustrating the timing of light distribution control in message transmission processing. Fig. 22C is a conceptual diagram illustrating the timing of light distribution control in message transmission processing. Fig. 23 is a flowchart illustrating an example of information reception processing in a receiving device. Fig. 24 is a sub-flowchart illustrating an example of header information reception processing. Fig. 25 is a sub-flowchart illustrating an example of message reception processing.

[0009] Modes for carrying out the invention (embodiments) will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially identical. Furthermore, the components described below can be combined as appropriate. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, for clarity of explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment. However, these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each figure, elements similar to those described above with reference to the previous figures may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0010] FIG. 1A is a side view showing an example of an optical communication device according to an embodiment. FIG. 1B is a perspective view showing an example of an optical element according to an embodiment. As shown in FIG. 1A, the optical communication device 1 includes a light source 4, a reflector 4a, and an optical element 100. As shown in FIG. 1B, the optical element 100 includes a first liquid crystal cell 2_1, a second liquid crystal cell 2_2, a third liquid crystal cell 2_3, and a fourth liquid crystal cell 2_4. The light source 4 is formed, for example, by a light-emitting diode (LED). The reflector 4a is a component that focuses light from the light source 4 onto the optical element 100.

[0011] In FIG. 1B , the Dz direction indicates the emission direction of light from the light source 4 and the reflector 4 a. The optical element 100 is configured by stacking a first liquid crystal cell 2_1, a second liquid crystal cell 2_2, a third liquid crystal cell 2_3, and a fourth liquid crystal cell 2_4 in the Dz direction. In the present disclosure, the optical element 100 is configured by stacking the first liquid crystal cell 2_1, the second liquid crystal cell 2_2, the third liquid crystal cell 2_3, and the fourth liquid crystal cell 2_4 in this order from the light source 4 side (the lower side of FIG. 1B ). In FIG. 1B , one direction of a plane parallel to the stacking plane of the first liquid crystal cell 2_1, the second liquid crystal cell 2_2, the third liquid crystal cell 2_3, and the fourth liquid crystal cell 2_4, which is perpendicular to the Dz direction, is defined as the Dx direction (first direction), and a direction perpendicular to both the Dx direction and the Dz direction is defined as the Dy direction (second direction).

[0012] The first liquid crystal cell 2_1, the second liquid crystal cell 2_2, the third liquid crystal cell 2_3, and the fourth liquid crystal cell 2_4 each have the same configuration. In the present disclosure, the first liquid crystal cell 2_1 and the fourth liquid crystal cell 2_4 are liquid crystal cells for p-wave polarization. Furthermore, the second liquid crystal cell 2_2 and the third liquid crystal cell 2_3 are liquid crystal cells for s-wave polarization. Hereinafter, the first liquid crystal cell 2_1, the second liquid crystal cell 2_2, the third liquid crystal cell 2_3, and the fourth liquid crystal cell 2_4 will also be collectively referred to as "liquid crystal cells 2."

[0013] The liquid crystal cell 2 includes a first substrate 5 and a second substrate 6. FIG. 2 is a schematic plan view of the first substrate as viewed from the Dz direction. FIG. 3 is a schematic plan view of the second substrate as viewed from the Dz direction. In FIG. 3, the drive electrodes are visible through the substrates, but the drive electrodes and wiring are shown with solid lines for clarity. FIG. 4 is a perspective view of a liquid crystal cell in which the first and second substrates are stacked in the Dz direction. In FIG. 4, the drive electrodes and wiring on the second substrate side are shown with solid lines, and the drive electrodes and wiring on the first substrate side are shown with dotted lines for clarity. FIG. 5 is a cross-sectional view taken along line A-A' in FIG. 4. Note that FIGS. 2, 3, 4, and 5 illustrate a third liquid crystal cell 2_3 and a fourth liquid crystal cell 2_4 in which the drive electrodes 10a and 10b of the first substrate 5 extend in the Dx direction and the drive electrodes 13a and 13b of the second substrate 6 extend in the Dy direction.

[0014] As shown in FIG. 5, the liquid crystal cell 2 includes a liquid crystal layer 8 between a first substrate 5 and a second substrate 6, the periphery of which is sealed with a sealing material 7.

[0015] The liquid crystal layer 8 modulates light passing through the liquid crystal layer 8 according to the state of the electric field. Positive nematic liquid crystal is used as the liquid crystal molecules, but other liquid crystals having a similar effect may also be used.

[0016] As shown in FIG. 2 , the liquid crystal layer 8 side of the base material 9 of the first substrate 5 is provided with a plurality of drive electrodes 10a, 10b, a plurality of metal wirings 11a, 11b that supply drive voltages to the drive electrodes 10a, 10b, and a plurality of metal wirings 11c, 11d that supply drive voltages to a plurality of drive electrodes 13a, 13b (see FIG. 3 ) provided on the second substrate 6, which will be described later. The metal wirings 11a, 11b, 11c, and 11d are provided in a wiring layer on the first substrate 5. The metal wirings 11a, 11b, 11c, and 11d are provided at intervals in the wiring layer on the first substrate 5. Hereinafter, the plurality of drive electrodes 10a, 10b may be simply referred to as "drive electrodes 10." Furthermore, the plurality of metal wirings 11a, 11b, 11c, and 11d may be referred to as "first metal wirings 11." 2, in the third liquid crystal cell 2_3 and the fourth liquid crystal cell 2_4, the drive electrodes 10 on the first substrate 5 extend in the Dx direction. Note that in the first liquid crystal cell 2_1 and the second liquid crystal cell 2_2, the drive electrodes 10 on the first substrate 5 extend in the Dy direction.

[0017] As shown in FIG. 3 , the liquid crystal layer 8 side of the base material 12 of the second substrate 6 shown in FIG. 5 includes multiple drive electrodes 13a and 13b and multiple metal wirings 14a and 14b that supply drive voltages to these drive electrodes 13. The metal wirings 14a and 14b are provided in the wiring layer of the second substrate 6. The metal wirings 14a and 14b are provided at intervals in the wiring layer on the second substrate 6. Hereinafter, the multiple drive electrodes 13a and 13b may be simply referred to as "drive electrodes 13." The multiple metal wirings 14a and 14b may be referred to as "second metal wirings 14." As shown in FIG. 3 , in the third liquid crystal cell 2_3 and the fourth liquid crystal cell 2_4, the drive electrodes 13 on the second substrate 6 extend in the Dy direction. Note that, in the first liquid crystal cell 2_1 and the second liquid crystal cell 2_2, the drive electrodes 13 on the second substrate 6 extend in the Dx direction.

[0018] The driving electrodes 10 and 13 are translucent electrodes formed of a translucent conductive material (translucent conductive oxide) such as ITO (indium tin oxide). The first substrate 5 and the second substrate 6 are translucent substrates such as glass or resin. The first metal wiring 11 and the second metal wiring 14 are formed of at least one metal material selected from aluminum (Al), copper (Cu), silver (Ag), molybdenum (Mo), and alloys thereof. The first metal wiring 11 and the second metal wiring 14 may also be formed as a laminated body in which a plurality of layers are stacked using one or more of these metal materials. At least one metal material selected from aluminum (Al), copper (Cu), silver (Ag), molybdenum (Mo), and alloys thereof has lower resistance than a translucent conductive oxide such as ITO.

[0019] The metal wiring 11c of the first substrate 5 and the metal wiring 14a of the second substrate 6 are connected by a conductive portion 15a made of, for example, conductive paste, etc. The metal wiring 11d of the first substrate 5 and the metal wiring 14b of the second substrate 6 are connected by a conductive portion 15b made of, for example, conductive paste, etc.

[0020] Furthermore, connection (Flex-on-Board) terminal portions 16a and 16b to be connected to a flexible printed circuit (FPC) (not shown) are provided in an area on the first substrate 5 that does not overlap with the second substrate 6 in the Dz direction. The connection terminal portions 16a and 16b each include four connection terminals corresponding to the metal wirings 11a, 11b, 11c, and 11d.

[0021] The connection terminals 16a and 16b are provided on the wiring layer of the first substrate 5. A drive voltage is supplied to the liquid crystal cell 2 from the FPC connected to the connection terminal 16a or the connection terminal 16b to be applied to the drive electrodes 10a and 10b on the first substrate 5 and the drive electrodes 13a and 13b on the second substrate 6. Hereinafter, the connection terminals 16a and 16b may be simply referred to as "connection terminals 16."

[0022] As shown in FIG. 4 , the liquid crystal cell 2 has the first substrate 5 and the second substrate 6 overlapping in the Dz direction (light irradiation direction), and the plurality of drive electrodes 10 on the first substrate 5 intersect with the plurality of drive electrodes 13 on the second substrate 6 as viewed from the Dz direction. In the liquid crystal cell 2 configured in this manner, the alignment direction of the liquid crystal molecules 17 in the liquid crystal layer 8 can be controlled by supplying drive voltages to the plurality of drive electrodes 10 on the first substrate 5 and the plurality of drive electrodes 13 on the second substrate 6, respectively. The region in which the alignment direction of the liquid crystal molecules 17 in the liquid crystal layer 8 can be controlled is referred to as the "effective area AA." In the effective area AA, the refractive index distribution of the liquid crystal layer 8 changes, thereby enabling control of the degree of diffusion of light passing through the effective area AA of the liquid crystal cell 2. The region outside the effective area AA, where the liquid crystal layer 8 is sealed with the sealant 7, is referred to as the "peripheral area GA" (see FIG. 5 ).

[0023] 5, in the effective area AA of the first substrate 5, the drive electrode 10 (drive electrode 10a in FIG. 5) is covered with an alignment film 18. In addition, in the effective area AA of the second substrate 6, the drive electrode 13 (drive electrodes 13a and 13b in FIG. 5) is covered with an alignment film 19. The alignment directions of the liquid crystal molecules in the alignment film 18 and the alignment film 19 are different.

[0024] 6A and 6B are diagrams showing the alignment directions of the alignment film on the first and second substrates, respectively.

[0025] As shown in Figures 6A and 6B, the alignment direction of the alignment film 18 on the first substrate 5 and the alignment direction of the alignment film 19 on the second substrate 6 intersect with each other in a plan view. Specifically, as shown by the solid arrow in Figure 6A, the alignment direction of the alignment film 18 on the first substrate 5 is perpendicular to the extension direction of the drive electrodes 10a and 10b shown by the dashed arrow in Figure 6A. Furthermore, as shown by the solid arrow in Figure 6B, the alignment direction of the alignment film 19 on the second substrate 6 is perpendicular to the extension direction of the drive electrodes 13a and 13b shown by the dashed arrow in Figure 6B. In the following description, the extension direction of each of the drive electrodes 10 and 13 and the alignment direction of the alignment films 18 and 19 covering them are described as being perpendicular to each other, but they may also intersect at an angle other than perpendicular, for example, an angle in the range of 85° to 90°. Furthermore, it is preferable that the drive electrodes 10 on the first substrate 5 side and the drive electrodes 13 on the second substrate 6 side are perpendicular to each other, but they may intersect at an angle ranging from 85° to 90°, for example. The alignment direction of the alignment films 18 and 19 is formed by a rubbing treatment or a photo-alignment treatment.

[0026] Here, the mechanism by which the shape of light is changed by each liquid crystal cell 2 (first liquid crystal cell 2_1, second liquid crystal cell 2_2, third liquid crystal cell 2_3, and fourth liquid crystal cell 2_4) will be described. FIG. 7 is a diagram showing the layered structure of the optical element according to the embodiment. FIGS. 8A, 8B, 8C, and 8D are conceptual diagrams for explaining the change in the shape of light by the optical element according to the embodiment. FIGS. 8A, 8B, 8C, and 8D show an example in which a potential difference is generated between each drive electrode of the shaded substrate of each liquid crystal cell 2.

[0027] 7, the optical element 100 is provided on the optical axis of the light source 4, indicated by the dashed line, and as described above, the first liquid crystal cell 2_1, the second liquid crystal cell 2_2, the third liquid crystal cell 2_3, and the fourth liquid crystal cell 2_4 are stacked in this order from the light source 4 side (the lower side in FIG. 7). The third liquid crystal cell 2_3 and the fourth liquid crystal cell 2_4 are stacked in a state rotated by 90° with respect to the first liquid crystal cell 2_1 and the second liquid crystal cell 2_2.

[0028] 6A and 6B , in each liquid crystal cell 2, the alignment direction of the alignment film intersects between the first substrate 5 side and the second substrate 6 side. As a result, the orientation of the liquid crystal molecules in the liquid crystal layer 8 gradually changes from the Dx direction to the Dy direction (or from the Dy direction to the Dx direction) as it moves from the first substrate 5 side to the second substrate 6 side, and the polarization component of the transmitted light rotates along this change. That is, in the liquid crystal cell 2, the polarization component that was a p-polarized component on the first substrate 5 side changes to an s-polarized component as it moves toward the second substrate 6 side, and the polarization component that was an s-polarized component on the first substrate 5 side changes to a p-polarized component as it moves toward the second substrate 6 side. This rotation of the polarization component may be referred to as optical rotation.

[0029] 8A shows a state in which no potential is generated between the adjacent electrodes of each liquid crystal cell 2. In this case, only optical rotation occurs in each liquid crystal cell 2, and none of the polarized light components are diffused.

[0030] 8B , for example, by generating a potential difference between the drive electrodes 10 a and 10 b on the first substrate 5 side of the first liquid crystal cell 2_1, the liquid crystal molecules are oriented in an arc shape between the electrodes, thereby forming a refractive index distribution along the Dx direction in the liquid crystal layer 8. When light from the light source 4 passes through in this state, the refractive index distribution acts on the polarized light component parallel to the Dx direction (the p-polarized component in FIG. 8B ), causing the p-polarized light component to diffuse in the Dx direction.

[0031] Furthermore, when a potential difference is also generated between the drive electrodes 13 a and 13 b on the second substrate 6 side of the first liquid crystal cell 2_1, a refractive index distribution in the Dy direction is formed on the second substrate 6 side, which causes the s-polarized component to diffuse in the Dy direction on the second substrate 6 side. That is, the polarized component that changed from a p-polarized component to an s-polarized component while passing through the liquid crystal layer 8 of the first liquid crystal cell 2_1 now diffuses in the Dy direction as well. On the other hand, the s-polarized component when incident on the first liquid crystal cell 2_1 undergoes optical rotation while passing through the liquid crystal layer 8, but becomes a polarized component that intersects with both refractive index distributions, and therefore passes through the first liquid crystal cell 2_1 with only optical rotation without being diffused.

[0032] The s-polarized light component that enters the first liquid crystal cell 2_1 is converted to a p-polarized light component after passing through the first liquid crystal cell 2_1, and the second liquid crystal cell 2_2 acts on the p-polarized light component. That is, as shown in FIGS. 8A and 8B , the first liquid crystal cell 2_1 acts on the p-polarized light component of the light that enters the optical element 100, and the second liquid crystal cell 2_2 acts on the s-polarized light component. The third liquid crystal cell 2_3 and the fourth liquid crystal cell 2_4 are rotated 90° relative to the first liquid crystal cell 2_1 and the second liquid crystal cell 2_2, so that the polarization components that act on them are also swapped by 90°. That is, the third liquid crystal cell 2_3 acts on the s-polarized light component that enters the optical element 100, and the fourth liquid crystal cell 2_4 acts on the p-polarized light component that enters the optical element 100.

[0033] 8C , in the optical element, by applying a potential difference between the drive electrodes extending in the Dy direction for each liquid crystal cell 2 (between the drive electrodes 10 a and 10 b on the first substrate 5 for the first liquid crystal cell 2_1 and the second liquid crystal cell 2_2, and between the drive electrodes 13 a and 13 b on the second substrate 6 for the third liquid crystal cell 2_3 and the fourth liquid crystal cell 2_4), the p-polarized light component can be acted upon, and the shape of the light can be enlarged mainly in the Dx direction. This effect may be referred to as lateral diffusion.

[0034] 8D , by applying a potential difference between the drive electrodes extending in the Dx direction for each liquid crystal cell 2 (between the drive electrodes 13 a and 13 b on the second substrate 6 in the first liquid crystal cell 2_1 and the second liquid crystal cell 2_2, and between the drive electrodes 10 a and 10 b on the first substrate 5 in the third liquid crystal cell 2_3 and the fourth liquid crystal cell 2_4), the s-polarized light component can be affected, and the shape of the light can be enlarged mainly in the Dy direction. This effect may be called vertical diffusion.

[0035] The degree of light diffusion in each direction depends on the potential difference between adjacent drive electrodes 10a and 10b (or between drive electrodes 13a and 13b). If the potential difference between drive electrodes 10a and 10b (or between drive electrodes 13a and 13b) is set to a predetermined maximum potential difference (e.g., 30 V), the light diffusion in that direction will be maximum (100%). If no potential difference is generated, no light diffusion will occur in that direction (0%). Alternatively, if the potential difference between drive electrodes 10a and 10b (or between drive electrodes 13a and 13b) is set to 50% of the maximum potential difference (e.g., 15 V), the light diffusion in that direction will be 50%. Note that if the relationship between the voltage difference and the light diffusion is not linear, a potential difference other than 15 V can be used.

[0036] The distance (also called the cell gap) between the substrates (between the first substrate 5 and the second substrate 6) of each liquid crystal cell 2 is wide, about 30 μm to 50 μm, which minimizes the influence of the electric field formed on one substrate on the other substrate. Furthermore, the drive voltage that generates a potential difference between adjacent drive electrodes 10 a, 10 b (or drive electrodes 13 a, 13 b) is a so-called AC rectangular wave, which, needless to say, prevents image sticking of the liquid crystal molecules.

[0037] In addition, the orientation direction of each orientation film, the extension direction of the drive electrodes of each substrate, and the angle between them can be changed as appropriate for the entire optical element 100 or for each liquid crystal cell 2 depending on the characteristics of the liquid crystal used and the optical properties desired to be achieved.

[0038] In this embodiment, the optical element 100 is described as having a configuration in which four liquid crystal cells, a first liquid crystal cell 2_1, a second liquid crystal cell 2_2, a third liquid crystal cell 2_3, and a fourth liquid crystal cell 2_4, are stacked together. However, this configuration is not limited to this, and it is also possible to use a configuration in which, for example, two or three liquid crystal cells 2 are stacked together, or a configuration in which five or more liquid crystal cells 2 are stacked together.

[0039] In the present disclosure, in the optical communication device 1 configured as described above, the light incident on the optical element from the light source 4 is controlled in two directions, the Dx direction (the direction of horizontal diffusion) and the Dy direction (the direction of vertical diffusion), by controlling the drive voltage of each liquid crystal cell 2. The vertical and horizontal diffusions may be collectively referred to as light diffusion. This changes the shape of the light emitted from the optical element. The light shape refers to the shape of the light appearing on a plane parallel to the exit surface of the optical element, and may also be referred to as the light distribution shape. The control of the degree of light diffusion in the present disclosure will now be described with reference to FIG. 9 .

[0040] 9 is a conceptual diagram for explaining the control of the degree of light diffusion by the optical communication device according to the embodiment. In FIG. 9, the light irradiation range is shown on a virtual plane xy perpendicular to the Dz direction. Note that the outline of the actual irradiation range may be slightly unclear due to factors such as the distance from the light source 4 and the light diffraction phenomenon.

[0041] As described above, the alignment direction of the liquid crystal molecules 17 in the liquid crystal layer 8 is controlled by supplying a drive voltage to each of the drive electrodes 10, 13 of each liquid crystal cell 2 of the optical element 100 provided on the optical axis of the light source 4. This controls the light distribution shape of the light emitted from the optical element 100.

[0042] Specifically, for example, as described above, the light distribution shape in the Dx direction changes depending on the drive voltage applied to the drive electrodes 10 or 13 extending in the Dy direction in each liquid crystal cell 2. Such diffusion of light in the Dx direction may be referred to as horizontal diffusion. Furthermore, the light distribution shape in the Dy direction changes depending on the drive voltage applied to the drive electrodes 10 or 13 extending in the Dx direction in the first to fourth liquid crystal cells. Such diffusion of light in the Dy direction may be referred to as vertical diffusion.

[0043] In the present disclosure, the minimum diffusivity of the horizontal and vertical diffusion is 0%, and the maximum diffusivity is 100%. More specifically, when the horizontal diffusivity is 0%, the drive electrodes that function to widen the light distribution in the Dx direction (e.g., the drive electrodes 10 extending in the Dy direction on the first substrate 5 of the first liquid crystal cell 2_1) do not affect the refractive index distribution of the liquid crystal layer 8. In this case, there is no potential difference between adjacent drive electrodes 10a, 10b, or no potential is supplied to the electrodes. On the other hand, when the horizontal diffusivity is 100%, the drive electrodes that function to widen the light distribution in the Dx direction (e.g., the drive electrodes 10 extending in the Dy direction on the first substrate 5 of the first liquid crystal cell 2_1) have the maximum effect on the refractive index distribution of the liquid crystal layer 8. In this case, the potential difference between adjacent drive electrodes 10a, 10b is set to the maximum potential difference (e.g., 30 V) in the optical element 100. When the horizontal diffusion degree is greater than 0% but less than 100%, a potential adjusted so that the potential difference between the adjacent drive electrodes 10a and 10b is greater than 0 V but less than the maximum potential difference (e.g., 30 V) is applied to the electrodes. The same applies to the vertical diffusion degree.

[0044] The outline a in Fig. 9 illustrates an illumination range when the horizontal diffusion rate and the vertical diffusion rate are both 100%. The outline b in Fig. 9 illustrates an illumination range when the horizontal diffusion rate is 100% and the vertical diffusion rate is 0%. The outline c in Fig. 9 illustrates an illumination range when the horizontal diffusion rate is 0% and the vertical diffusion rate is 100%. The outline d in Fig. 9 illustrates an illumination range when the horizontal diffusion rate and the vertical diffusion rate are both 0%. That is, the outline d shows the light distribution state when light from the light source 4 is emitted without being controlled by the optical element 100 (i.e., transmitted through the optical element 100 as is).

[0045] In the optical communication device 1 configured as described above, the horizontal diffusivity and vertical diffusivity of the light emitted from the optical element 100 can be controlled by controlling the drive voltage of each liquid crystal cell 2. This makes it possible to change the light distribution shape of the light emitted from the optical communication device 1. Hereinafter, the control that changes the light distribution shape of the light emitted from the optical communication device 1 will also be referred to as "light distribution control."

[0046] A method for transmitting Morse-coded information using the optical communication device 1 capable of controlling the light distribution pattern as described above will be described below.

[0047] (Embodiment 1) Fig. 10 is a diagram showing a schematic configuration of an optical communication system 200 according to embodiment 1. As shown in Fig. 10, the optical communication system 200 according to embodiment 1 includes an optical communication device 1 and a control device 300. The control device 300 is exemplified by a portable communication terminal device such as a smartphone or a tablet. In the present disclosure, the optical communication device 1 includes the above-described optical element 100 and is configured to be capable of controlling light distribution in two directions, the Dx direction and the Dy direction.

[0048] Data and various command signals are transmitted and received between the control device 300 and the optical communication device 1 via a communication means. In the present disclosure, the communication means is, for example, a wireless communication means such as Bluetooth (registered trademark) or Wi-Fi (registered trademark). The control device 300 and the optical communication device 1 may perform wireless communication via a predetermined network such as a mobile communication network. Alternatively, the control device 300 and the optical communication device 1 may be connected by wire and perform wired communication.

[0049] In the present disclosure, the control device 300 has a function of transmitting character information to be Morse coded and various setting information required for Morse coding and transmission to the optical communication device 1. The optical communication device 1 Morse codes the character information transmitted from the control device 300 based on the various setting information and transmits it.

[0050] Fig. 11 is a block diagram showing an example of a control device 300 according to embodiment 1. As shown in Fig. 11 , the control device 300 according to embodiment 1 includes a display panel 20, a touch sensor 30, a processing circuit 310, a detection circuit 311, a memory circuit 323, a communication circuit 325, and a display control circuit 331.

[0051] The display control circuit 331 is a circuit that executes display control processing for the display panel 20. The detection circuit 311 is a circuit that detects whether or not the touch sensor 30 has been touched, based on detection signals output from each detection element 31 of the touch sensor 30. The detection circuit 311 is configured by, for example, a detection IC. Alternatively, the detection circuit 311 and the display control circuit 331 may be mounted on the display panel 20 as a single display IC. The display panel 20, the touch sensor 30, the detection circuit 311, and the display control circuit 331 function as an HMI (Human Machine Interface) in the control device 300.

[0052] The processing circuit 310 is a component realized by, for example, a CPU of a smartphone, tablet, or the like that constitutes the control device 300.

[0053] The memory circuitry 323 is a component realized by, for example, RAM, EEPROM, ROM, etc. of a smartphone, tablet, or the like that constitutes the control device 300.

[0054] The communication circuit 325 is configured, for example, by a wireless communication module of a smartphone, tablet, or the like that constitutes the control device 300. The communication circuit 325 is a circuit that performs communication with the optical communication device 1.

[0055] In the present disclosure, the memory circuitry 323 stores text information (hereinafter also referred to as a “message”) to be transmitted to the optical communication device 1 and various setting information.

[0056] The various setting information in the first embodiment includes the language of the message (Roman or Japanese), the number of repetitions R, the code length s, the code interval i, the message interval e, etc. The contents of the message body and the setting values ​​of the various setting information may be input by the user operating the control device 300, or may be transmitted to the control device 300 from an external device (not shown) and stored in the memory circuitry 323.

[0057] Fig. 12 is a block diagram showing an example of the optical communication device 1 according to the embodiment 1. As shown in Fig. 12, the optical communication device 1 according to the embodiment 1 includes a processing circuit 110, a communication circuit 111, an electrode driving circuit 112, a light source driving circuit 113, and a memory circuit 114 as control blocks for controlling the light source 4 and the optical element 100 described above.

[0058] The electrode driving circuit 112 is a circuit that supplies a driving voltage corresponding to the light distribution shape to each of the driving electrodes 10, 13 of each liquid crystal cell 2 of the optical element 100. The light distribution control rate in the optical communication device 1 is defined by the sampling rate (sps: samples per second) of the DA converter for driving the electrodes. The light source driving circuit 113 is a circuit that supplies a driving current corresponding to each control parameter such as light emission intensity and light emission color to the light source 4. The processing circuit 110 is composed of, for example, a microcomputer. The memory circuit 114 is composed of, for example, a RAM, an EEPROM, a ROM, etc. The communication circuit 111 is a circuit that communicates with the control device 300.

[0059] In the present disclosure, the memory circuitry 114 stores messages and various setting information transmitted from the control device 300. The processing circuitry 110 converts the messages transmitted from the control device 300 into Morse code.

[0060] Morse code is a character code that is variable-length coded by combining short dots (・) and long dots (-), and is generally transmitted as a pulse-width modulated (PWM) Morse code. In this case, the short dots (・) and long dots (-) are defined by their code lengths. For this reason, transmission times may be long depending on the content and amount of information in the message.

[0061] In the present disclosure, the optical communication device 1 transmits information by combining a first light distribution shape corresponding to the short dot symbol "." and a second light distribution shape corresponding to the long dot symbol "-." In other words, in the present disclosure, the short dot symbol "." and the long dot symbol "-" are defined by the light distribution shape of the optical communication device 1. This allows the transmission time of Morse-coded information to be shortened.

[0062] Fig. 13A is a diagram showing a specific example of a first light distribution shape. Fig. 13B is a diagram showing a specific example of a second light distribution shape. An example of the first light distribution shape is a light distribution state in which the horizontal diffusion degree and the vertical diffusion degree are both 0%, as shown in Fig. 13A. An example of the second light distribution shape is a light distribution state in which the horizontal diffusion degree is 100% and the vertical diffusion degree is 0%, as shown in Fig. 13B.

[0063] In this embodiment, the length of the period during which the first light distribution shape or the second light distribution shape is maintained in the information transmission process described below is defined as the "code length s." The interval between successive codes is defined as the "code interval i." The repetition interval when a series of messages is repeatedly transmitted is defined as the "message interval e."

[0064] The first and second light distribution shapes are not limited to those shown in Figures 13A and 13B. The first and second light distribution shapes may be different from each other. Specifically, for example, the second light distribution shape may be a light distribution state in which the horizontal diffusion degree is 0% and the vertical diffusion degree is 100%, or a light distribution state in which the horizontal diffusion degree and the vertical diffusion degree are both 100%.

[0065] Fig. 14 is a flowchart showing an example of information transmission processing in the optical communication system 200 according to embodiment 1. Here, an example will be described in which the information transmission processing shown in Fig. 14 is started when the optical communication device 1 receives a message transmitted from the control device 300.

[0066] The message (text information) sent from the control device 300 and various setting information such as the language of the message (Roman or Japanese), the number of repetitions R, the code length s, the code interval i, the message interval e, etc. are stored in the memory circuit 114 of the optical communication device 1 (step S101).

[0067] The processing circuit 110 of the optical communication device 1 determines whether the message (text information) is in Roman or Japanese (step S102), converts the message into Morse code (step S103), and stores it in the memory circuit 114.

[0068] In the present disclosure, a conversion table for converting a message (character information) into Morse code is stored in advance in the memory circuit 114. A known Morse code table can be used as the conversion table. Hereinafter, the Morse-coded message will also be referred to as a "character information code."

[0069] Here, the number of symbols in the character information code (the total number of short dot symbols "." and long dot symbols "-") is defined as N. The processing circuit 110 resets the repetition number r (r is an integer equal to or less than R) (r=0, step S104) and increments the repetition number r (r=r+1, step S105). Next, the processing circuit 110 resets the code number n (n is an integer equal to or less than N) (n=0, step S106) and increments the code number n (n=n+1, step S107).

[0070] The processing circuit 110 reads the n-th code of the character information code and determines whether the code is a dot code "." or a dash code "-." Specifically, the processing circuit 110 determines whether the n-th code of the character information code is a dot code "." (step S108).

[0071] If the nth symbol in the character information code is a dot symbol "." (step S108; Yes), the processing circuit 110 controls the electrode driving circuit 112 to supply a driving voltage to each driving electrode 10, 13 of each liquid crystal cell 2 of the optical element 100 so that the light distribution state of the optical element 100 becomes the first light distribution shape (step S109).

[0072] If the nth symbol in the character information code is a dash "-" (step S108; No), the processing circuit 110 controls the electrode driving circuit 112 to supply a driving voltage to each of the driving electrodes 10, 13 of each liquid crystal cell 2 of the optical element 100 so that the light distribution state of the optical element 100 becomes the second light distribution shape (step S110).

[0073] Then, the processing circuit 110 controls the light source drive circuit 113 to turn on the light source 4 (step S111), thereby transmitting the n-th code.

[0074] The processing circuit 110 determines whether the code length s has elapsed (step S112). If the code length s has not elapsed (step S112; No), the processing circuit 110 repeatedly executes the process of step S112 until the code length s has elapsed. If the code length s has elapsed (step S112; Yes), the processing circuit 110 controls the light source drive circuit 113 to turn off the light source 4 (step S113). The code length s is set to, for example, 500 ms.

[0075] Next, the processing circuit 110 determines whether the code number n has reached the number of codes N of the character information code (step S114).

[0076] If the code number n is less than the number of codes N of the character information code (step S114; No), the processing circuit 110 determines whether the code interval i has elapsed (step S115). If the code interval i has not elapsed (step S115; No), the processing circuit 110 repeatedly executes the processing of step S115 until the code interval i has elapsed. If the code interval i has elapsed (step S115; Yes), the processing circuit 110 returns to the processing of step S107 and repeatedly executes the processing up to step S114. The code interval i is set to, for example, 100 ms.

[0077] When the code number n reaches the number of codes N of the character information code (step S114 returns Yes), the processing circuit 110 determines whether the message interval e has elapsed (step S116). If the message interval e has not elapsed (step S116 returns No), the processing circuit 110 repeats the process of step S116 until the message interval e has elapsed. The message interval e is set to, for example, 1000 ms.

[0078] When the message interval e has elapsed (step S116; Yes), the processing circuit 110 determines whether the repetition number r has reached the repetition count R (step S117). If the repetition number r is less than the repetition count R (step S117; No), the processing circuit 110 returns to the processing of step S105 and repeatedly executes the processing up to step S117.

[0079] When the repetition number r reaches the number of repetitions R (step S117; Yes), the information transmission process shown in FIG. 14 ends.

[0080] According to the optical communication device 1 and optical communication system 200 according to the first embodiment described above, the processing circuit 110 of the optical communication device 1 generates a character information code by converting a message (character information) into Morse code, and controls the light distribution state of the optical element 100 to a first light distribution shape when transmitting a short dot symbol "." in the generated character information code, and controls the light distribution state of the optical element 100 to a second light distribution shape different from the first light distribution shape when transmitting a long dot symbol "-" in the character information code. This makes it possible to read the Morse-coded message (character information) by visually checking the light distribution state of the optical element 100 in the optical communication device 1.

[0081] 15 is a diagram showing a schematic configuration of an optical communication system according to embodiment 2. As shown in Fig. 15, an optical communication system 200a according to embodiment 2 includes an optical communication device 1a, a control device 300, and a receiving device 400. The receiving device 400 is exemplified by a portable communication terminal device such as a smartphone or a tablet.

[0082] In the present disclosure, the receiving device 400 has a function of decoding the Morse code transmitted from the optical communication device 1 a. In the optical communication system 200 a according to the second embodiment, a protocol for transmitting the Morse code (hereinafter also referred to as a "transmission protocol") is shared in advance between the optical communication device 1 a and the receiving device 400. The transmission protocol defines the format of header information including various setting information when transmitting a character information code, a data transmission rate b (second data transmission rate) when transmitting the header information, and the like.

[0083] Fig. 16 is a block diagram showing an example of a receiving device 400 according to embodiment 2. As shown in Fig. 16 , the receiving device 400 according to embodiment 2 includes a display panel 40, an image sensor 50, a processing circuit 410, an image capturing circuit 411, a storage circuit 423, and a display control circuit 431.

[0084] In the present disclosure, the imaging element 50 is an image sensor that acquires changes in the light distribution state of the optical communication device 1 a. Examples of the image sensor include a solid-state imaging element such as a complementary metal oxide semiconductor (CMOS) image sensor, but are not limited thereto and may also be a charge coupled device (CCD) image sensor, for example.

[0085] The display control circuit 431 is a circuit that executes display control processing for the display panel 40. The imaging circuit 411 is a circuit that acquires the light distribution state of the optical communication device 1a based on pixel signals output from each pixel of the imaging element 50. The imaging circuit 411 is configured with, for example, an image processing IC. The display panel 40 and the display control circuit 431 function as an HMI (Human Machine Interface) in the receiving device 400. The imaging element 50 and the imaging circuit 411 function as a camera for acquiring the light distribution state of the optical communication device 1a as image data.

[0086] The processing circuit 410 is a component realized by, for example, a CPU of a smartphone, tablet, or the like that constitutes the receiving device 400 .

[0087] The memory circuitry 423 is a component realized by, for example, RAM, EEPROM, ROM, etc. of a smartphone, tablet, or the like that constitutes the receiving device 400.

[0088] In the present disclosure, image data acquired by the camera (the image sensor 50 and the image acquisition circuit 411) is stored in the memory circuit 423. The processing circuit 410 analyzes the acquired image data and decodes the Morse code transmitted from the optical communication device 1a.

[0089] The various setting information in the second embodiment includes the language of the message (Roman or Japanese), the data transmission rate B (first data transmission rate) when transmitting the character information code, the number of repetitions R, etc. The content of the message body and the setting values ​​of the various setting information may be input by the user operating the control device 300a, or may be transmitted to the control device 300a from an external device (not shown) and stored in the memory circuitry 323.

[0090] Fig. 17 is a flowchart showing an example of information transmission processing in the optical communication system 200a according to embodiment 2. Here, an example will be described in which the information transmission processing shown in Fig. 17 is started when the optical communication device 1a receives a message transmitted from the control device 300a.

[0091] The message (text information) sent from the control device 300a and various setting information such as the language of the message (Roman or Japanese), data transmission rate B, and number of repetitions R are stored in the memory circuit 114 of the optical communication device 1a (step S201).

[0092] The processing circuit 110 of the optical communication device 1a generates header information (step S202), converts the header information into Morse code (step S203), and stores the converted header information in the storage circuit 114. Fig. 18 is a diagram showing an example of header information.

[0093] 18 illustrates an example of multiple pieces of header information defined by header information numbers P ("5", "4", ..., "1" in FIG. 18). Each piece of header information includes a start code "S" indicating the start position, a header information number P ("5", "4", ..., "1" in FIG. 18), a data transmission rate B ("30" (bps: bit per second) in FIG. 18), a repetition count R ("3" (times) in FIG. 18), and an end code "E" indicating the end position.

[0094] The conversion table used to convert header information into Morse code can be the same as the conversion table used to convert a message (character information) into Morse code. Hereinafter, the header information corresponding to the Morse-coded header information number P ("5", "4", ..., "1" in Figure 18) will also be referred to as the "header code".

[0095] The processing circuit 110 executes a header information transmission process (step S204). Fig. 19 is a sub-flowchart showing an example of the header information transmission process.

[0096] 19 , the processing circuitry 110 first resets the light distribution control counter value C for the light distribution control rate S of the optical communication device 1a (C=0, step S301). Then, the processing circuitry 110 resets the countdown number p (p is an integer equal to or less than P+1) (p=6, step S302) and decrements the countdown number p (p=p−1, step S303). Next, the processing circuitry 110 sets the number of symbols in the header code (the total number of short dot symbols “·” and long dot symbols “-”) to M, resets the symbol number m (m is an integer equal to or less than M) (m=0, step S304), and increments the symbol number m (m=m+1, step S305).

[0097] Next, the processing circuit 110 increments the light distribution control counter value C (C=C+1, step S306), and determines whether the value of C(b / S) is an integer (step S307).

[0098] If the value of C(b / S) is not an integer (step S307; No), processing circuit 110 executes exceptional processing that differs from the light distribution control in the header information transmission processing (step S308). Specifically, in the exceptional processing, processing circuit 110 controls electrode driving circuit 112 to supply driving voltages to driving electrodes 10, 13 of each liquid crystal cell 2 of optical element 100 such that the light distribution state of optical element 100 is substantially different from the first light distribution shape and the second light distribution shape.

[0099] After the exception handling is performed in step S308, the process returns to step S306, and the processes from step S306 to step S308 are repeatedly performed.

[0100] If the value of C(b / S) is an integer (step S307; Yes), the processing circuitry 110 reads the m-th symbol in the header code and determines whether the m-th symbol is a dot symbol "." or a dash symbol "-." Specifically, the processing circuitry 110 determines whether the m-th symbol is a dot symbol "." (step S309).

[0101] If the mth symbol in the header code is a dot symbol "." (step S309; ​​Yes), the processing circuit 110 controls the electrode driving circuit 112 to supply a driving voltage to each driving electrode 10, 13 of each liquid crystal cell 2 of the optical element 100 so that the light distribution state of the optical element 100 becomes the first light distribution shape (step S310).

[0102] If the m-th symbol in the header code is a dash symbol "-" (step S309; ​​No), the processing circuit 110 controls the electrode driving circuit 112 to supply a driving voltage to each of the driving electrodes 10 and 13 of each liquid crystal cell 2 of the optical element 100 such that the light distribution state of the optical element 100 becomes the second light distribution pattern (step S311). This causes the m-th symbol in the header code to be transmitted.

[0103] 20A, 20B, and 20C are conceptual diagrams illustrating the timing of light distribution control in the header information transmission process. In Fig. 20A, 20B, and 20C, light distribution control in the header information transmission process (step S310 or step S311) is executed at the shaded light distribution control timings.

[0104] The example shown in Fig. 20A shows an example where the data transmission rate b is 30 bps and the light distribution control rate S is 120 sps. The example shown in Fig. 20B shows an example where the data transmission rate b is 630 bps and the light distribution control rate S is 120 sps. The example shown in Fig. 20C shows an example where the data transmission rate b is 120 bps and the light distribution control rate S is 120 sps.

[0105] Next, the processing circuit 110 determines whether the code number m has reached the number of codes M of the header code (step S312).

[0106] If the code number m is less than the number of codes M of the header code (step S312; No), the processing circuit 110 returns to the processing of step S305 and repeatedly executes the processing up to step S312.

[0107] When the code number m reaches the number of codes M in the header code (step S312; Yes), the processing circuit 110 determines whether the countdown number p has reached "1" (step S313). If the countdown number p is greater than "1" (step S313; No), the processing circuit 110 returns to the processing of step S303 and repeats the processing up to step S313.

[0108] When the countdown number p reaches "1" (step S313; Yes), the header information transmission process shown in FIG. 19 ends, and the process returns to the information transmission process shown in FIG.

[0109] Returning to the information transmission process shown in Fig. 17, the processing circuit 110 of the optical communication device 1a determines whether the message (character information) is in Roman or Japanese (step S205), converts the message into Morse code (step S206), and stores the character information code converted into Morse code in the memory circuit 114. Fig. 21 is a sub-flowchart showing an example of the message transmission process.

[0110] 21, the processing circuitry 110 first resets the light distribution control counter value C=0 for the light distribution control rate S of the optical communication device 1a (C=0, step S401). Then, the processing circuitry 110 resets the repetition number r (r is an integer equal to or less than R) (r=0, step S402), and increments the repetition number r (r=r+1, step S403).

[0111] Here, the number of symbols in the character information code (the total number of short dot symbols "." and long dot symbols "-") is set to N. The processing circuit 110 resets the symbol number n (n is an integer equal to or less than N) (n=0, step S404), and then increments the symbol number n (n=n+1, step S405).

[0112] Next, the processing circuit 110 increments the light distribution control counter value C (C=C+1, step S406), and determines whether the value of C(B / S) is an integer (step S407).

[0113] If the value of C(B / S) is not an integer (step S407; No), the processing circuit 110 executes exceptional processing that differs from the light distribution control in the message transmission processing (step S408). Specifically, in the exceptional processing, the processing circuit 110 controls the electrode driving circuit 112 to supply driving voltages to the driving electrodes 10 and 13 of the liquid crystal cells 2 of the optical element 100 such that the light distribution state of the optical element 100 is substantially different from the first light distribution shape and the second light distribution shape.

[0114] After the exception handling is performed in step S408, the process returns to step S406, and the processes from step S406 to step S408 are repeatedly performed.

[0115] If the value of C(B / S) is an integer (step S407; Yes), the processing circuit 110 reads the nth symbol of the character information code and determines whether the nth symbol is a dot symbol "." or a dash symbol "-." Specifically, the processing circuit 110 determines whether the nth symbol of the character information code is a dot symbol "." (step S409).

[0116] If the nth symbol in the character information code is a dot symbol "." (step S409; Yes), the processing circuit 110 controls the electrode driving circuit 112 to supply a driving voltage to each driving electrode 10, 13 of each liquid crystal cell 2 of the optical element 100 so that the light distribution state of the optical element 100 becomes the first light distribution shape (step S410).

[0117] If the n-th symbol in the character information code is a dash symbol "-" (step S409; No), the processing circuit 110 controls the electrode driving circuit 112 to supply a driving voltage to each of the driving electrodes 10 and 13 of each liquid crystal cell 2 of the optical element 100 such that the light distribution state of the optical element 100 becomes the second light distribution pattern (step S411). This allows the n-th symbol in the character information code to be transmitted.

[0118] 22A, 22B, and 22C are conceptual diagrams illustrating the timing of light distribution control in the message transmission process. In Fig. 22A, 22B, and 22C, light distribution control in the message transmission process (step S410 or step S411) is executed at the shaded light distribution control timing.

[0119] The example shown in Fig. 22A shows an example where the data transmission rate B is 30 bps and the light distribution control rate S is 120 sps. The example shown in Fig. 22B shows an example where the data transmission rate B is 630 bps and the light distribution control rate S is 120 sps. The example shown in Fig. 22C shows an example where the data transmission rate B is 120 bps and the light distribution control rate S is 120 sps.

[0120] Next, the processing circuit 110 determines whether the code number n has reached the number of codes N of the character information code (step S412).

[0121] If the code number n is less than the number of codes N of the character information code (step S412; No), the processing circuit 110 returns to the processing of step S405 and repeats the processing up to step S412.

[0122] When the code number n becomes the number of codes N of the character information code (step S412; Yes), the processing circuit 110 determines whether the repetition number r becomes the number of times the message is repeated R (step S413). If the repetition number r is less than the number of times the message is repeated R (step S413; No), the processing circuit 110 returns to the processing of step S403 and repeatedly executes the processing up to step S413.

[0123] When the number of repetitions r reaches the number of repetitions R (step S413; Yes), the optical communication device 1a transmits an end code "E" indicating the end position (step S414), terminates the message transmission process shown in FIG. 21, returns to the information transmission process shown in FIG. 17, and terminates the information transmission process.

[0124] 23 is a flowchart showing an example of information reception processing in the receiving device 400. As a prerequisite for the information reception processing shown in FIG. 23 , the camera (image sensor 50 and image capture circuit 411) of the receiving device 400 acquires the light distribution state of the optical communication device 1a as image data at a frame rate at least equal to or higher than the light distribution control rate of the optical communication device 1a, based on the above-mentioned transmission protocol. The acquired image data is stored in the memory circuit 423 of the receiving device 400.

[0125] Specifically, if the sampling rate of the DA converter for driving the electrodes of the optical communication device 1a is 120 sps, the camera (imaging element 50 and imaging circuit 411) of the receiving device 400 acquires image data at a frame rate of 120 fps (frames per second) or higher, which makes it possible to suppress code loss when acquiring the header code and character information code.

[0126] First, the receiving device 400 receives the header information transmitted from the optical communication device 1a based on the above-mentioned transmission protocol (step S501). Fig. 24 is a sub-flowchart showing an example of the header information receiving process.

[0127] In the header information reception process shown in FIG. 24, the processing circuit 410 of the receiving device 400 first resets the counter value C corresponding to the light distribution control timing at the light distribution control rate S of the optical communication device 1a (C=0, step S601).

[0128] Next, the processing circuit 410 increments the counter value C (C=C+1, step S602), and stores the image data acquired by the camera (image sensor 50 and image capture circuit 411) of the receiving device 400 in the memory circuit 423 (step S603).

[0129] Next, the processing circuitry 410 analyzes the acquired image data and determines whether the light distribution state of the optical element 100 transmitted from the optical communication device 1a is the first light distribution shape (step S604). If it is the first light distribution shape (step S604; Yes), the processing circuitry 410 stores it in the memory circuitry 423 as a dot symbol "." in Morse code (step S605).

[0130] If the light distribution shape is not the first light distribution shape (step S604; No), processing circuitry 410 then determines whether the light distribution shape is the second light distribution shape (step S606).If the light distribution shape is the second light distribution shape (step S606; Yes), processing circuitry 410 stores the Morse code dash symbol "-" in memory circuitry 423 (step S607).

[0131] If the light distribution shape is not the second light distribution shape (step S606; No), the process returns to step S602.

[0132] By the above-described image data analysis, header code symbols are sequentially stored in the memory circuit 423 of the receiving device 400. The processing circuit 410 sequentially decodes the symbols stored in the memory circuit 423 to obtain various setting information included in the header information. A known method can be used as the image data analysis method in the receiving device 400. The present disclosure is not limited to the image data analysis method in the receiving device 400.

[0133] The processing circuit 410 determines whether or not the start code "S" has been detected (step S608). If the start code "S" has not been detected (step S608; No), the processing returns to step S602.

[0134] If the start code "S" is detected (step S608; Yes), the processing circuit 410 then determines whether or not the header information number P is detected (step S609). If the header information number P is not detected (step S609; No), the processing returns to step S602.

[0135] When the header information number P is detected (step S609; Yes), the processing circuit 410 stores the detected header information number P in the memory circuit 423 (step S610).

[0136] Next, the processing circuit 410 determines whether or not the data transmission rate B of the character information code has been detected (step S611). If the data transmission rate B of the character information code has not been detected (step S611; No), the processing returns to step S602.

[0137] When the data transmission rate B of the character information code is detected (step S611; Yes), the processing circuit 410 stores the detected data transmission rate B of the character information code in the storage circuit 423 (step S612).

[0138] Next, the processing circuit 410 determines whether or not the message repetition count R has been detected (step S613). If the message repetition count R has not been detected (step S613; No), the processing returns to step S602.

[0139] When the number of times R of message repetition is detected (step S613; Yes), the processing circuitry 410 stores the number of times R of message repetition detected in the memory circuitry 423 (step S614).

[0140] Next, the processing circuit 410 determines whether or not the end code "E" indicating the end position of the character information code has been detected (step S615). If the end code "E" indicating the end position of the character information code has not been detected (step S615; No), the processing returns to step S602.

[0141] When the end code "E" indicating the end position of the character information code is detected (step S615; Yes), the processing circuit 410 determines whether the header information number P=1 has been stored in the memory circuit 423 (step S616).

[0142] If the header information number P=1 is not stored in the memory circuit 423 (step S616; No), the process returns to step S601. If the header information number P=1 is stored in the memory circuit 423 (step S616; Yes), the header information reception process shown in Fig. 24 is terminated, and the process returns to the information reception process shown in Fig. 23.

[0143] The above-described header information reception process acquires the data transmission rate B of the character information code and the number of message repetitions R included in the header information. Furthermore, the transmission start timing of the character information code can be defined, for example, by the interval between acquisitions of header information number P. Specifically, for example, the position obtained by adding the acquisition interval of header information number P to the acquisition timing of header information number P=1 may be acquired as the transmission start timing of the character information code. This allows the processing circuit 410 of the receiving device 400 to acquire the transmission start timing of the character information code by analyzing the header information acquired by the above-described header information reception process.

[0144] Returning to the information reception process shown in Fig. 23, the processing circuit 410 receives the message transmitted from the optical communication device 1a based on the various setting information acquired by the header information reception process described above (step S502). Fig. 25 is a sub-flowchart showing an example of the message reception process.

[0145] 25, the processing circuit 410 of the receiving device 400 resets a counter value C corresponding to the light distribution control timing at the light distribution control rate S of the optical communication device 1a at the transmission start timing of the character information code acquired by the header information reception process described above (C=S / B-1, step S701). Here, for example, if the data transmission rate B of the character information code is 30 bps, the value of C=S / B-1 becomes "3."

[0146] Next, the processing circuit 410 increments the counter value C (C=C+1, step S702) and determines whether the value of C(B / S) is an integer (step S703). For example, if the data transmission rate B is 30 bps, the counter value C becomes "4" in the first step S702, and the value of C(B / S) becomes "1" in the subsequent step S703.

[0147] If the value of C(B / S) is not an integer value (step S703; No), the process returns to step S702.

[0148] If the value of C(B / S) is an integer value (step S703; Yes), the processing circuit 410 stores the image data acquired by the camera (image sensor 50 and image capture circuit 411) of the receiving device 400 in the memory circuit 423 (step S704).

[0149] Next, the processing circuitry 410 analyzes the acquired image data and determines whether the light distribution state of the optical element 100 transmitted from the optical communication device 1a is the first light distribution shape or the second light distribution shape. Specifically, the processing circuitry 410 determines whether the light distribution state of the optical element 100 transmitted from the optical communication device 1a is the first light distribution shape (step S705).

[0150] If the light distribution shape is the first light distribution shape (step S705; Yes), processing circuitry 410 stores the Morse code short dot symbol "." in memory circuitry 423 (step S706). If the light distribution shape is the second light distribution shape (step S705; No), processing circuitry 410 stores the Morse code long dot symbol "-" in memory circuitry 423 (step S707).

[0151] Next, the processing circuit 410 determines whether or not the end code "E" indicating the end position of the character information code has been detected (step S708). If the end code "E" indicating the end position of the character information code has not been detected (step S708; No), the processing returns to step S702. Thereafter, the code of the character information code is sequentially acquired at the timing when the value of C(B / S) becomes an integer value (Integer) in step S703.

[0152] When the end code "E" indicating the end position of the character information code is detected (step S708; Yes), the message receiving process shown in FIG. 25 is terminated, and the process returns to the information receiving process shown in FIG. 23, whereupon the information receiving process is terminated.

[0153] According to the optical communication system 200a according to the second embodiment, the receiving device 400 has a function of decoding the Morse code transmitted from the optical communication device 1a, thereby enabling high-speed information transmission.

[0154] Furthermore, when transmitting header information, it is transmitted at a data transmission rate b (second data transmission rate) predefined between the optical communication device 1a and the receiving device 400, and when transmitting character information code, it is transmitted at a data transmission rate B (first data transmission rate) included in the header information. The receiving device 400 can then obtain the transmission start timing of the character information code by analyzing the header information.

[0155] According to the above-described embodiments, an optical communication device and an optical communication system capable of reducing the transmission time of Morse-coded information can be obtained.

[0156] Although preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to such embodiments. The contents disclosed in the embodiments are merely examples, and various modifications are possible within the scope of the present disclosure. For example, if the optical communication device of the present disclosure is capable of adjusting not only the light distribution shape but also the brightness and color of the light, a configuration for adjusting the brightness and color of the light using the configuration of the present disclosure can also be adopted. Appropriate modifications made within the scope of the present disclosure also naturally fall within the technical scope of the present disclosure.

[0157] REFERENCE SIGNS LIST 1, 1a Optical communication device 2 Liquid crystal cell 2_1 First liquid crystal cell 2_2 Second liquid crystal cell 2_3 Third liquid crystal cell 2_4 Fourth liquid crystal cell 4 Light source 5 First substrate 6 Second substrate 7 Sealant 8 Liquid crystal layer 9 Base material 10, 10a, 10b Drive electrode 11 First metal wiring 11a, 11b, 11c, 11d Metal wiring 12 Base material 13, 13a, 13b Drive electrode 14 Second metal wiring 14a, 14b Metal wiring 15a, 15b Conductive portion 16a, 16b Connection terminal portion 17 Liquid crystal molecule 18 Alignment film 19 Alignment film 20, 40 Display panel 30 Touch sensor 31 Detection element 100 Optical element 110 Processing circuit 111 Communication circuit 112 Electrode drive circuit 113 Light source driving circuit 114 Memory circuit 200, 200a Optical communication system 300, 300a Control device 310 Processing circuit 311 Detection circuit 323 Memory circuit 325 Communication circuit 331 Display control circuit 400 Receiving device 410 Processing circuit 411 Imaging circuit 423 Memory circuit 431 Display control circuit AA Effective area GA Peripheral area

Claims

1. An optical communications device comprising: a light source; an optical element arranged on the optical axis of the light source and controlling the light distribution state of light emitted from the light source; and a processing circuit for controlling the light distribution of the optical element, wherein the processing circuit generates a character information code by converting character information into Morse code, controls the light distribution state of the optical element to a first light distribution shape when transmitting a short dot code of the character information code, and controls the light distribution state of the optical element to a second light distribution shape different from the first light distribution shape when transmitting a long dot code of the character information code.

2. An optical communications system comprising: an optical communications device; and a control device that transmits character information to the optical communications device, wherein the optical communications device comprises: a light source; an optical element arranged on the optical axis of the light source and controlling the light distribution state of light emitted from the light source; and a processing circuit that controls the light distribution of the optical element, wherein the processing circuit generates a character information code by converting character information into Morse code, controls the light distribution state of the optical element to a first light distribution shape when transmitting a short dot code of the character information code, and controls the light distribution state of the optical element to a second light distribution shape different from the first light distribution shape when transmitting a long dot code of the character information code.

3. The optical communication system according to claim 2, wherein the control device transmits setting information for transmitting the character information code to the optical communication device.

4. The optical communication system described in claim 3, wherein the setting information includes at least a first data transmission rate when transmitting the character information code, and the processing circuit controls the light distribution state of the optical element at the first data transmission rate when transmitting the character information code.

5. The optical communication system according to claim 4, further comprising a receiving device for decoding the Morse code transmitted from said optical communication device.

6. The optical communication system described in claim 5, wherein a second data transmission rate is defined between the optical communication device and the receiving device when transmitting at least header information including the setting information, and the processing circuit controls the light distribution state of the optical element at the second data transmission rate when transmitting the header information.

7. The optical communication system according to claim 6, wherein the receiving device obtains a transmission start timing of the character information code based on the header information.

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