JP6507606B2 - Underwater lighting device - Google Patents

Description

  The present invention relates to an underwater lighting device using coherent light, and more particularly to an underwater lighting device capable of irradiating light into the sea with reduced reflection loss at the sea surface.

  Underwater lighting devices for lighting the water are available for use. For example, Patent Document 1 discloses a fish lamp that projects light into the sea to gather fish in the sea. The fish lamp shown in Patent Document 1 illuminates the sea by controlling the light distribution of a large number of regularly arranged LEDs using a lens or the like.

JP, 2011-134692, A

  However, even if the light distribution of a large number of LEDs is controlled, it is affected by the reflection loss at the sea surface, and it is not yet sufficient as the light utilization efficiency. When a large number of LEDs are used, although the light quantity increases, the size of the light source increases, the straightness of the light beam decreases, and even if the light distribution characteristic is controlled using a lens etc. It can not be obtained, and it is difficult to allow light to reach deep into the water. Nowadays, in which limited energy is required to be efficiently used, techniques for further improving the light utilization efficiency are required.

  This invention is made in view of such a point, and it aims at providing the underwater lighting device which can irradiate light into the sea by reducing the reflection loss in the sea surface.

  The underwater lighting device according to the present invention radiates coherent light whose polarization direction is uniform from outside to outside of the water.

  In the underwater illumination device according to the present invention, the coherent light emitted from the underwater illumination device toward water may be light having more p-polarization components than s-polarization components.

  In the underwater illumination device according to the present invention, the coherent light having the same polarization direction is irradiated from the outside of the water to the water through a retardation plate, and the coherent light transmitted through the retardation plate is more than an s-polarization component. Also, it may be light having many p-polarization components.

  In the underwater lighting device according to the present invention, some of the plurality of coherent light beams, each of which has the same polarization direction, may be selectively irradiated from the outside of the water toward the water.

  In the underwater illumination device according to the present invention, a coherent light source for emitting coherent light having a uniform polarization direction, an optical element for diffusing the coherent light and directing it into water, and an optical scan for scanning the coherent light on the optical element And a member.

  In the underwater lighting device according to the present invention, the optical element has a diffusion area for diffusing incident coherent light to illuminate a virtual illumination area, the diffusion area including a plurality of element diffusion areas, the plurality Each of the elementary diffusion areas of the second group illuminates the partial illumination areas in the corresponding virtual illumination area by diffusion of the incident coherent light, and at least a part of each partial illumination area deviates from the other partial illumination areas It may be

  In the underwater illumination device according to the present invention, the optical element may be a hologram recording medium, and each of the plurality of element diffusion regions may be an element hologram region in which different interference fringe patterns are formed.

  In the underwater lighting device according to the present invention, the optical element may be a lens array group having a plurality of lens arrays, and the plurality of element diffusion regions may respectively correspond to the plurality of lens arrays.

  According to the present invention, since coherent light having a uniform polarization direction can be directed to water, it is possible to selectively irradiate coherent light having a polarization direction with low reflection loss on the water surface. As a result, the reflection loss on the water surface can be reduced to improve the light utilization efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows schematic structure of the ship provided with the underwater illuminating device by one Embodiment of this invention. FIG. 2 is a schematic view of the underwater lighting device shown in FIG. FIG. 2 is a schematic perspective view showing the configuration of the light scanning member in detail. The schematic perspective view which shows a mode that the laser beam diffused by the optical element illuminates a virtual illumination range. The perspective view which shows the example which the underwater illuminating device shown in FIG. 1 further equips with a phase difference plate.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of easy illustration and understanding, the scale, the dimensional ratio in the vertical and horizontal directions, etc. are appropriately changed from those of the actual one and exaggerated.

  In addition, as used in the present specification, the shape or geometric condition and the degree thereof are specified. For example, terms such as “parallel”, “orthogonal”, “identical”, values of length and angle, etc. Without being bound by the meaning, it shall be interpreted including the extent to which the same function can be expected.

  FIG. 1 is a view showing a schematic configuration of a ship 50 provided with an underwater lighting device 1 according to an embodiment of the present invention. The underwater lighting device 1 shown in FIG. 1 is attached to the bow of a ship 50. The underwater lighting device 1 emits coherent light L whose polarization direction is uniform toward the sea from the atmosphere. According to the ship 50 shown in FIG. 1, it becomes possible to selectively irradiate the coherent light L in the deflection direction with a low reflection loss at the sea surface S. As a result, the reflection loss at the sea surface S can be reduced to improve the light utilization efficiency. Hereinafter, each component which comprises the underwater lighting apparatus 1 is explained in full detail.

  FIG. 2 is a schematic view showing a schematic configuration of the underwater lighting device 1. As shown in FIG. 2, the illumination unit 2 includes an illumination device 4 and an optical element 5. Among these, the irradiation device 4 has a laser light source 6 and a light scanning member 7.

  The laser light source 6 emits coherent light, that is, laser light whose polarization direction is uniform. In the present embodiment, the case of using the laser light source 6 that emits light having more p-polarization components than s-polarization components is described. In addition, the laser light source 6 may have a plurality of light source units 8 that emit a plurality of laser beams having different emission wavelength ranges. The plurality of light source units 8 may be provided independently, or may be a light source module in which the plurality of light source units 8 are arranged side by side on a common substrate. The laser light source 6 of the present embodiment only needs to have at least two light source units 8 having different emission wavelength ranges, and the number of types of emission wavelength ranges may be two or more. Moreover, in order to increase the light emission intensity, a plurality of light source units 8 may be provided for each light emission wavelength range.

  For example, in the case where the laser light source 6 includes the light source unit 8 r in the red light emission wavelength range, the light source unit 8 g in the green light emission wavelength range, and the light source unit 8 b in the blue light emission wavelength range, these light source units 8 It becomes possible to generate white illumination light La by superimposing the three laser lights emitted.

  FIG. 3 shows an example of the configuration of the light scanning member 7. The light scanning member 7 temporally changes the traveling direction of the laser light from the laser light source 6 so that the traveling direction of the laser light is not constant. As a result, the laser beam emitted from the light scanning member 7 scans the incident surface of the optical element 5.

  The light scanning member 7 has a reflective device 13 rotatable about two rotation axes 11 and 12 extending in directions intersecting with each other, as shown in FIG. The laser light from the laser light source 6 incident on the reflection surface 13 a of the reflection device 13 is reflected at an angle corresponding to the inclination angle of the reflection surface 13 a and travels in the direction of the incident surface 5 a of the optical element 5. By rotating the reflective device 13 around the two rotation axes 11 and 12, the laser light scans the incident surface 5 a of the optical element 5 two-dimensionally. The reflecting device 13 repeats an operation of rotating around the two rotation axes 11 and 12 at, for example, a fixed period, so that the laser light repeatedly two-dimensionally scans the incident surface 5 a of the optical element 5 in synchronization with this period. .

  In the present embodiment, it is assumed that only one light scanning member 7 is provided, and a plurality of laser beams emitted by the laser light source 6 are all incident on the common light scanning member 7 and the light scanning is performed. The traveling direction is changed with time by the member 7 to scan the optical element 5.

  The optical element 5 has the above-described incident surface 5a on which a plurality of laser beams are incident, diffuses the plurality of laser beams incident on the incident surface 5a, and illuminates the virtual illumination range 20 provided at a predetermined position. (pass.

  FIG. 4 is a view showing how the laser light diffused by the optical element 5 illuminates the virtual illumination range 20. The optical element 5 has a plurality of diffusion regions 14 corresponding to a plurality of laser beams having different emission wavelength ranges. The corresponding laser light is incident on each diffusion region 14. The laser light diffused in each diffusion area 14 illuminates the actual illumination range after passing through the virtual illumination range 20.

  When it is desired to perform illumination control for each partial illumination range in the virtual illumination range 20, it is necessary to further divide each diffusion region 14 into a plurality of element diffusion regions 15 as shown in FIG. Each element diffusion area 15 diffuses the incident laser light to illuminate a partial illumination area 19 in the virtual illumination area 20. At least a part of the partial illumination area 19 is different for each element diffusion area 15.

  Note that it is arbitrary whether or not each diffusion region 14 is divided into a plurality of element diffusion regions 15 and illumination control is performed for each partial illumination range 19 in the virtual illumination range 20. When it is desired to simply cause light to uniformly enter the entire virtual illumination range 20, it is not necessary to divide each diffusion region 14 into a plurality of element diffusion regions 15. In the following, as an example, when the hologram recording medium 16 is used as the optical element 5, an example of dividing the hologram recording medium 16 into a plurality of element hologram areas 18 corresponding to a plurality of element diffusion areas 15 and recording interference fringes Will be explained.

  The hologram recording medium 16 corresponding to the optical element 5 has a plurality of hologram areas 17 corresponding to the plurality of diffusion areas 14 as shown in FIG. 4, for example. Each hologram area 17 is provided corresponding to each of a plurality of laser beams having different emission wavelength ranges. Each hologram area 17 has an incident surface 17a on which the corresponding laser beam is incident. Any laser light that has been incident on the incident surface 17 a of each hologram area 17 and diffused therein illuminates the virtual illumination range 20. For example, when the hologram recording medium 16 has three hologram areas 17, the laser light diffused in each hologram area 17 illuminates the actual illumination area after passing through the entire virtual illumination area 20.

  Although FIG. 4 shows an example in which three hologram regions 17 are provided in correspondence with three laser beams emitting in red, blue or green, the hologram recording medium 16 according to the present embodiment has different emission wavelength ranges. It is sufficient to have two or more hologram regions 17 in association with two or more laser beams. As shown in FIG. 4, when the hologram recording medium 16 has three hologram areas 17 corresponding to three laser beams emitting in red, blue or green, each hologram area 17 covers the entire virtual illumination area 20. In the case where three laser beams are emitted, the light that illuminates the virtual illumination range 20 is illuminated in white.

  The size or area of each hologram area 17 in the hologram recording medium 16 does not have to be the same. Even if the size of each hologram area 17 is different, adjusting the interference fringes formed on the incident surface 17a of each hologram area 17 for each hologram area 17 makes each hologram area 17 a common virtual illumination range 20. Light can be incident.

  Each of the plurality of hologram areas 17 has a plurality of elementary hologram areas 18 corresponding to the plurality of elementary diffusion areas 15. Each of the plurality of elementary hologram areas 18 illuminates the partial illumination area 19 within the virtual illumination area 20 by diffusing the incident laser light. At least a part of the partial illumination area 19 illuminated by each elementary hologram area 18 is different for each elementary hologram area 18. That is, the partial illumination areas 19 illuminated by different elementary hologram areas 18 are at least partially different.

  An interference fringe pattern is formed on the incident surface 17 a of each element hologram area 18. Thus, the laser light incident on the incident surface 17 a of each elementary hologram area 18 is diffracted by the interference fringe pattern on the incident surface 17 a and illuminates the corresponding partial illumination area 19 on the virtual illumination area 20. By adjusting the interference fringe pattern variously, it is possible to change the traveling direction of the laser light diffracted or diffused in each element hologram area 18.

  Thus, the laser light incident on each point in each elementary hologram area 18 illuminates the corresponding partial illumination area 19. In addition, the light scanning member 7 temporally changes the incident position and the incident angle of the laser light incident on each element hologram area 18. The laser light incident in one elementary hologram area 18 illuminates a common partial illumination area 19 regardless of the position in the elementary hologram area 18. This means that the incident angle of the laser light incident on each point of the partial illumination range 19 changes with time. The change in the incident angle is a speed that can not be resolved by the human eye, and as a result, the scattering pattern of uncorrelated laser light is multiplexed and observed to the human eye. Therefore, the speckles generated corresponding to each scattering pattern are superimposed, averaged and observed by the observer. Thereby, speckles become less noticeable in the virtual illumination range 20. Further, since the laser light from the light scanning member 7 sequentially scans each element hologram area 18 on the hologram recording medium 16, the laser light diffracted at each point in each element hologram area 18 has different wavefronts. Since these laser beams are independently superimposed on the virtual illumination range 20, in the virtual illumination range 20, a uniform illuminance distribution in which speckles are inconspicuous can be obtained.

  In this manner, each of the plurality of coherent lights diffused by the optical element 5 of the underwater lighting device 1 passes through the virtual illumination area 20, passes through the sea surface S, and travels in the water. In the present embodiment, each coherent light L emitted from the underwater lighting device 1 has the same polarization direction for each coherent light L. For example, as such an example, it may be assumed that the underwater illumination device 1 emits each coherent light L mainly composed of p-polarization components.

  In particular, the underwater lighting device 1 can emit coherent light L in the polarization direction with low reflection loss at the sea surface S. Specifically, since the sea surface S is along the horizontal plane, the underwater lighting device 1 can irradiate the coherent light L in which the p-polarization component is more than the s-polarization component toward the sea. From the viewpoint of further reducing the reflection loss at the sea surface S, the incident angle to the sea surface S of the coherent light L emitted from the underwater lighting device 1 is preferably close to the Brewster's angle. Such coherent light L with low reflection loss at the sea surface S can reach deep in the sea with high energy density.

  Next, an example of the usage method of the underwater illuminating device 1 which consists of the above structures is demonstrated. In the following description, an example in which the underwater lighting device 1 is applied to aquaculture of fish will be described as an example.

  For example, fish with positive phototropism such as squid, sardines, mackerel, salmon, and saury have the habit of gathering in light. For this reason, in order to collect fish having positive phototaxis, it is preferable to irradiate from the underwater lighting device 1 coherent light L that reaches deep water, that is, coherent light L with low reflection loss at the sea surface S. Good. Therefore, coherent light L having more p-polarization components than s-polarization components is emitted from the underwater lighting device 1 toward the sea.

  On the other hand, for example, fish with negative phototaxis such as red sea bream and hamo have a tendency to move away from light. For this reason, when coherent light L that reaches deep water, ie, coherent light L with low reflection loss at sea surface S, is irradiated from underwater lighting device 1, the fish having negative phototaxis escapes away from the light .

  In particular, even for fish having positive to negative phototaxis, it is conceivable that the degree to which they gather or move away varies depending on the color of light, that is, the wavelength of light. Therefore, the underwater illumination device 1 according to the present embodiment selectively uses some of the three light source units 8 to selectively select some of the three coherent light beams having the same polarization direction. Can also be irradiated. For example, the underwater lighting device 1 uses the light source unit 8 r in the red light emission wavelength range of the three light source units 8 and the light source unit 8 g in the green light emission wavelength range to obtain red and green light having uniform polarization directions. Coherent light in the emission wavelength range of This makes it possible to emit appropriate coherent light L according to the type of fish having positive to negative phototaxis.

  As described above, according to the present embodiment, the coherent light L having the same polarization direction is irradiated from the outside of the water toward the water. According to such a configuration, the coherent light L having the same polarization direction can be irradiated toward the water, so that the coherent light L having the polarization direction with low reflection loss at the sea surface S can be selectively selected from the underwater lighting device 1 It can be irradiated. As a result, the reflection loss at the sea surface S can be reduced to improve the light utilization efficiency.

  Further, according to the present embodiment, the coherent light L irradiated from the underwater lighting device 1 toward the water is light having more p-polarization components than s-polarization components. Since the sea surface S is along the horizontal surface, the reflection loss at the sea surface S can be significantly suppressed by irradiating the water with coherent light L having more p-polarization components than s-polarization components.

  Further, according to the present embodiment, it is possible to selectively irradiate some of the plurality of coherent lights L, each of which has the same polarization direction, from the outside of the water to the water. In this case, it is possible to irradiate appropriate coherent light L according to the type of fish having phototaxis.

  Further, according to the present embodiment, the optical element 5 includes the diffusion area 14 for diffusing the incident coherent light to illuminate the virtual illumination range 20, and the diffusion area 14 includes the plurality of element diffusion areas 15. And each of the plurality of element diffusion regions 15 illuminates the partial illumination area 19 in the virtual illumination area 20 corresponding to each by diffusion of the incident coherent light, and at least a portion of each partial illumination area 19 is , And the other partial illumination range 19. According to such an embodiment, it is possible to easily adjust the light distribution of the underwater lighting device 1.

  In the above-described embodiment, as shown in FIG. 2, the laser light source 6 includes the plurality of light source units 8. However, the configuration of the laser light source 6 is not limited to such an example. For example, the laser light source 6 may emit laser light of a single wavelength range.

  In addition, even in the case where coherent light having different emission wavelength ranges is emitted from the plurality of light source units 8, the light source does not necessarily emit laser light in the wavelength ranges of red, green and blue. For example, the light source may emit laser light in a yellow or violet wavelength range. In this case, the wavelength selection filter 21 may transmit light in the yellow and violet wavelength ranges.

  In the above description, an example in which the hologram recording medium 16 is used as the optical element 3 has been described, but the specific form of the optical element 3 is not limited to the hologram recording medium 16. For example, the optical element 3 may be configured using a lens array group in which each element diffusion area 15 is one lens array. In this case, a lens array is provided for each element diffusion area 15, and the shape of each lens array is designed such that each lens array illuminates the partial illumination area 19 in the virtual illumination area 20. And the position of each partial illumination range 19 differs at least in part. As a result, as in the case where the optical element 3 is configured using the hologram recording medium 16, it is possible to change the illumination color of only a part of the virtual illumination range 20 or not to illuminate only a part.

  Further, in the embodiment described above, the coherent light emitted from the laser light source 6 is light having a p-polarization component more than the s-polarization component, and is emitted from the underwater lighting device 1 while maintaining this polarization direction. However, the present invention is not limited to such an example, and after the polarization direction of the coherent light emitted from the laser light source 6 is adjusted by appropriately combining a retardation plate and a polarization beam splitter, the adjusted coherent light L is subjected to underwater illumination It may be released from the device 1. FIG. 5 shows an example in which a retardation plate 9 is further provided to adjust the polarization direction of the coherent light emitted from the laser light source 6.

  In the example shown in FIG. 5, the retardation plate 9 is provided in the optical path of the coherent light L emitted from the laser light source 6. Specifically, the retardation plate 9 is disposed between the light scanning member 7 and the optical element 5.

  In the retardation plate 9, the direction of the slow axis is determined according to the polarization direction of the coherent light L emitted from the laser light source 6. In the example shown in FIG. 5, the coherent light from the laser light source 6 is irradiated from the atmosphere to the water through the retardation plate 9 and the coherent light L transmitted through the retardation plate 9 is more than the s-polarization component. The light has a large amount of p-polarization components. As described above, the reflection loss at the sea surface S can be significantly suppressed by irradiating the water with the coherent light L in which the p-polarization component is more than the s-polarization component.

  The aspects of the present invention are not limited to the above-described individual embodiments, but include various modifications that those skilled in the art can conceive, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications and partial deletions can be made without departing from the conceptual idea and spirit of the present invention derived from the contents defined in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 underwater illumination unit 2 illumination unit, 4 illumination device, 5 optical element, 6 laser light source, 7 light scanning member, 8 light source part, 9 phase difference plate, 11,12 rotation axis, 13 reflection device, 14 diffusion area, 15 element Diffusion area, 16 hologram recording medium, 17 hologram area, 17a entrance plane, 18 element hologram area, 19 partial illumination area, 20 illuminated area, 50 ships

Claims (6)

An underwater lighting apparatus for irradiating coherent light having a uniform polarization direction from outside the water to the water , comprising:
A coherent light source that emits coherent light whose polarization directions are aligned;
An optical element that diffuses the coherent light and directs it into water;
A light scanning member for scanning the coherent light on the optical element;
Equipped with
The optical element has a diffusion area that diffuses incident coherent light to illuminate a virtual illumination range,
The diffusion region includes a plurality of element diffusion regions,
Each of the plurality of element diffusion regions illuminates a partial illumination range within a virtual illumination range corresponding to each by diffusion of incident coherent light;
An underwater lighting device , wherein at least a portion of each partial illumination range is offset from other partial illumination ranges .   The underwater lighting device according to claim 1, wherein the coherent light irradiated from the underwater lighting device toward water is light having a p-polarization component more than an s-polarization component. The coherent light having the same polarization direction is irradiated from the outside of the water to the water through the retardation plate,
The underwater lighting device according to claim 1, wherein the coherent light transmitted through the retardation plate is light having a p-polarization component more than an s-polarization component.   The underwater lighting device according to any one of claims 1 to 3, wherein it is possible to selectively irradiate some of the plurality of coherent light beams, each of which has the same polarization direction, from the outside of the water to the water. . The optical element is a hologram recording medium,
The underwater lighting device according to any one of claims 1 to 4, wherein each of the plurality of element diffusion regions is an element hologram region in which different interference fringe patterns are formed. The optical element is a lens array group having a plurality of lens arrays,
The underwater lighting device according to any one of claims 1 to 4, wherein the plurality of element diffusion regions respectively correspond to the plurality of lens arrays.

Images