Optical fiber display apparatus

Abstract: An optical fiber display apparatus (10) comprises a display panel, (16) and a plurality of optical fibers, (28) one end of each being optically connected to a light source (20A, 20B), and the other end thereof being implanted in the panel (16) from one surface side thereof, so that the end face thereof is exposed at the other surface of the panel (16). A fixing device (22) is used for implanting of the fibers, and includes a sleeve (24) detachably inserted and held in a through hole formed in the panel, and a ferrule (28) detachably inserted in the sleeve (24) from a side of one end thereof and held therein, the other end of each of the fibers being received and fixed in the ferrule. A second ferrule may be detachably inserted in the sleeve from a side of the other end thereof, to be thus suspended from the other surface of the panel. One end of a decorative optical fiber is received and fixed in the second ferrule to be thus suspended from the display panel. Preferably, the decorative fiber comprises a core, and a cladding surrounding the core, a plurality of cone-shaped openings being discretely formed in the surface thereof so that light conducted in the core is allowed to partially leak out of the cone-shaped openings, whereby the decorative effect is increased.

Description: BACKGROUND OF THE INVENTION 1) Field of the Invention The present invention relates to a display apparatus utilizing optical fibers, especially decorative optical fibers which may be advantageously utilized when the display apparatus is constituted as a decorative illumination such as a chandelier. 2) Description of the Related Art In an optical fiber display apparatus as disclosed by GB-A-2 114 353, a plurality of optical fibers are implanted in a display panel in such a manner that an end face of each optical fiber is exposed on a display surface of the panel. The other end faces of the optical fibers are optically connected to a light source, so that a light guided from the light source through each optical fiber is emitted from the exposed end face thereof, whereby images, characters, marks, symbols or the like can be displayed on the display surface of the panel. This optical fiber display apparatus has many advantages or merits in comparison with another display apparatus. For example, the optical fiber display apparatus can provide a very large display area which cannot be realized by a cathode-ray tube (CRT) display. Also, maintenance of the optical fiber display apparatus is easier than that of an LED large size display apparatus having a display panel on which a plurality of light emitting devices (LED) are mounted. Conventionally, the optical fibers in the display panel are implanted by inserting the optical fibers through holes formed in the display panel, an adhesive is applied to a location at which each optical fiber is inserted, and after the adhesive has hardened, the exposed end faces of the implanted optical fibers are polished by a suitable abrasive machine or tool. These procedures are very troublesome, especially on site, and although the optical fiber display apparatus may be assembled in a factory, this is not preferable because it is costly to transport the assembled apparatus, due to a bulkiness thereof and because the optical fibers may be broken during the shipping thereof. In the conventional implanting operation, an exchange of a broken optical fiber for a new one is very difficult, due to the adhesive holding the optical fibers in the panel. The display apparatus may be constituted as a decorative illumination, such as a chandelier, by extending and suspending the optical fibers from the display surface of the panel. In this case, the disadvantages as mentioned above are substantially the same for the decorative illumination. In the optical fiber decorative illumination, the suspended optical fibers are frequently notched so that light leaks out of the notches of each optical fiber, resulting in increase of an optically decorative effect of the optical fibers. Nevertheless, the conventionally notched or decorative optical fibers do not sufficiently increase the optically decorative effect, because the notches are formed as a V-shaped groove. Namely, the V-shaped groove must be shallow, to prevent a breaking of the decorative optical fiber, as much as possible, at the notched location. That is, if the notches are deeply formed in the optical fibers, to thereby increase the optically decorative effect thereof, these decorative optical fibers are very easily broken. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical fiber display apparatus wherein a plurality of first and second optical fibers, the second optical fibers suspending from the display surface of the panel, can be easily implanted in a display panel without the using of an adhesive, and wherein a broken and implanted optical fiber can be easily and quickly exchanged for a new one. In accordance with the present invention, there is provided an optical fiber display apparatus comprising the features of appended claim 1. The implanting means as defined in claim 1 may further include a quick nut engageable with the sleeve member inserted in the through hole of the display panel, whereby the sleeve member is held therein. Preferably, the first and second ferrule member as defined in claim 1 are made of a plastically deformable material so that the fixing of the other end of each of the first plurality of optical fibers in the first ferrule member and of the one end of each of the second plurality of optical fibers in the second ferrule member can be carried out by a partial swaging of the first and second ferrule members, respectively. BRIEF DESCRIPTION OF THE DRAWINGS The other objects and advantages of the present invention will be better understood from the following description, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of an optical fiber display apparatus which does not form part of the present invention; Figure 2 is an enlarged longitudinal sectional view of a fixing device used in the optical fiber display apparatus shown in Fig. 1 and also does not form part of the invention; Figure 3 is an exploded view of the fixing device shown in Fig. 2; Figure 4 is a plane view of a push-on or quick nut forming a part of the fixing device shown in Figs. 2 and 3; Figure 5 is a longitudinal sectional view of a another type of ferrule member forming a part of the fixing device shown in Figs. 2 and 3; Figure 6 is a schematic view of an optical fiber display apparatus according to the present invention; Figure 7 is an enlarged longitudinal sectional view of a fixing device used in the optical fiber display apparatus shown in Fig. 6; Figure 8 is an exploded view of the fixing device shown in Fig. 7; Figure 9 is a longitudinal sectional view of a decorative optical fiber advantageously usable in the optical fiber display apparatus shown in Fig. 6; Figure 10 is a longitudinal sectional view similar to Fig. 9, showing a modification of the decorative optical fiber shown in Fig. 9; and Figure 11 is a longitudinal sectional view similar to Fig. 9, showing another modification of the decorative optical fiber shown in Fig. 9. DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 does not form part of the invention and is described to aid understanding of the invention. Figure 1 schematically shows an optical fiber display apparatus constituted such that a fixed image is decoratively displayed. This optical fiber display apparatus is intended to be suspended from a ceiling of a hall or room. The display apparatus comprises a box-like casing 10 preferably made of a suitable composite material or a suitable hard synthetic resin material, and including a side wall frame 12, a top wall 14 integrally formed therewith, and a bottom wall 16 detachably attached thereto. The bottom wall 16 sonstitutes a display panel in which a plurality of through holes are formed, these through holes defining the fixed image to be displayed on an outer display surface of the panel 16. The display apparatus also comprises a plurality of optical fibers 18, which are divided into two groups A and B. The optical fibers of group A are gathered together at one end thereof, and are optically connected to a light source 20A attached to an inner wall portion of the side wall frame 12. Similarly, the optical fibers of group B are gathered together at one end thereof, and are optically connected to a light source 20B attached to an opposed inner wall portion of the side wall frame 12. The other end of each of the optical fibers 18 of the groups A and B is implanted in the panel 16 by using a fixing device 22 as shown in Figs. 2 and 3 which also does not form a part of the present invention. The fixing device 22 comprises a sleeve member 24 inserted to the through hole formed in the panel 16, a push-on or quick nut 26 for engaging with and fastening the inserted sleeve member 24 to the panel 16, and a ferrule member 28 held by the sleeve member 24 and having the optical fiber 18 fixed therein. The sleeve member 24 may be made of a suitable metal material or a suitable hard synthetic resin material, and includes a sleeve body 24a having an outer diameter that is slightly smaller than an inner diameter of the through hole formed in the panel 16, and a flange 24b integrally formed at one end of the sleeve body 24a. As best shown in Fig. 3, the sleeve body 24a has a small opening 24c formed at the other end side thereof, and a ridge element 24d integrally formed on the inner wall surface thereof and at one side of the othe end thereof. Note, when the sleeve member 24 is made of the metal material, the ridge element 24d may be formed by pressing. The sleeve member 24 is inserted to the through hole of the panel 16 from the outer display surface side thereof, until the flange 24b is abutted thereagainst, as shown in Fig. 2. The insertion of the sleeve member 24 may be carried out by pulling up same with a suitable tool engaged with the small opening 24c, if necessary. After the sleeve member 24 is inserted, the quick nut 26 is engaged with a portion of the sleeve body 24a projected from an inner surface of the panel 16. The quick nut 26 is preferably made of a steel material, and comprises an annular ring plate 26a and four pawl elements 26b integrally and inwardly extended therefrom, as apparent from Figs. 3 and 4. The diameter of a circle defined by inner edges of the pawl elements 26b is slightly smaller than that of the sleeve body 24a. and accordingly, when the quick nut 26 is forcibly pressed onto the sleeve body 24a, the four pawl elements 26 are firmly engaged with the outer surface of the sleeve body 24a, whereby the sleeve member 24 is prevented from dropping out of the through hole of the panel 16. The ferrule member 28 is made of a plastically deformable material such as a suitable metal or a suitable synthetic resin, and includes a tubular body 28a for receiving the optical fiber 18 therein, and a flange 28b integrally formed at one end thereof. As best shown in Fig. 3, the tubular body 28a has a reduced thin portion 28a 1 and an enlarged thick portion 28a 2 integrated therewith. The reduced thin portion 28a 1 is swaged by a suitable tool after the optical fiber 18 is received in the ferrule 28, so that the received optical fiber 18 is immovably fixed within the tubular body 28a. Note, after the optical fiber 18 is fixed in the ferrule member 28, the end face of the optical fiber 18 is treated, if necessary. An outer diameter of the enlarged thick portion 28a 2 is slightly smaller than the inner diameter of the sleeve body 24a, so that the ferrule member 28 can be inserted into the sleeve member 24 until the flange 28b of the ferrule member 28 is abutted against the end of the sleeve member 24, as shown in Fig. 2. Nevertheless, the ferrule member 28 must be forcibly inserted in the sleeve member 24 to enable it to pass over the ridge element 24d integrally formed on the inner wall surface thereof, i.e., the inserted ferrule member 28 is firmly held within the sleeve member 24 by the engagement of the ferrule member 28 with the ridge element 24d. The ferrule member 28 held by the sleeve member 24 can withstand a pulling force of at least from 3 to 5 kg, and thus the ferrule member 28 is not easily removed from the sleeve member 24. In place of the ridge element 24d, projections may be formed on the inner wall surface of the sleeve member 24, so that the ferrule member 28 can withstand a pulling force of more than 5 kg. Note, in the embodiment as mentioned above, although the ridge element 24d is provided on the inner wall surface of the sleeve member 24, it may be formed on the outer surface of the ferrule member 28. With the above arrangement of the fixing device 22, the implanting of the optical fibers 18 in the panel 18 is easier and quicker in comparison with the conventional implanting of optical fibers in which an adhesive is used for fixing same, and thus the optical fiber display apparatus as shown in Fig. 1 can be advantageously assembled by use of the fixing device 22, especially on site. Preferably, a protective transparent board 30, which may be made of a glass or acrylic resin, is attached to the display surface of the panel 16, to protect the exposed end faces of the optical fibers 18 from pollution or contamination whenever necessary. Figure 5 shows another type of ferrule member, generally indicated by a reference numeral 32, which includes a thin tubular body 32a and a flange 32b integrally formed at one end thereof. The tubular body 32a has substantially the same diameter as the enlarged thick portion 28a 2 of the ferrule member 28, but an inner diameter thereof is larger than that of the ferrule member 28 for receiving an optical fiber 34 having a larger diameter than that of the optical fiber 18. Namely, the single sleeve member 24 can be commonly used for the two ferrule members 28 and 32 in which the optical fibers 18 and 34 having different diameters are received. In the ferrule member 32, the tubular body 32a must be partially swaged before the optical fiber 34 can be fixed in the ferrule member 32. It is preferable to prepare various type ferrules having the same diameter and different inner diameters (for example, from 0.25 to 3.0 mm). Figure 6 shows an optical fiber display apparatus constituted as a decorative illumination such as a chandelier. This display apparatus comprises a box-like casing 36 which may be constituted in substantially the same manner as the casing 10. A bottom wall 38 of the casing 36 serves as a display panel in which a plurality of through holes are formed. The display apparatus also comprises a first plurality of optical fibers 40 which are divided into two groups C and D. The optical fibers of group C are gathered together at one end thereof and are optically connected to a light source 42C attached to an inner wall portion of the side wall frame of the casing 36. Similarly, the optical fibers of group D are gathered together at one end thereof and are optically connected to a light source 42D attached to an opposed inner wall portion of the side wall frame of the casing 36. The other ends of each of the optical fibers 40 of the groups C and D are implanted in the panel 38. The display apparatus further comprises a second plurality of optical fibers 44, one end of each is implanted in the panel 38 to be thus suspended therefrom, and is optically connected to the corresponding one end of the implanted optical fibers 40. The implanting and connecting of the optical fibers 40, 44 is carried out by using a fixing device 46 as shown in Figs. 7 and 8. The fixing device 46 comprises a sleeve member 48 inserted to the through hole formed in the panel 38, a push-on or quick nut 50 for engaging with and fastening the inserted sleeve member 48 to the panel 38. a first ferrule member 52 held by the sleeve member 48 and having the optical fiber 40 fixed therein, and a second ferrule member 54 held by the sleeve member 48 and having the optical fiber 44 fixed therein. The sleeve member 48 may be made of a suitable metal material or a suitable hard synthetic resin material, and includes a sleeve body 48a having an outer diameter sligthly than an inner diameter of the through hole formed in the panel 38, and a flange 48b integrally formed at one end of the sleeve body 48a. As best shown in Fig. 8, the sleeve body 48a has a small opening 48c formed at the side of the other end thereof, and first and second ridge elements 48d and 48e integrally formed on the inner wall surface thereof and at the sides of the ends thereof, respectively. When the sleeve member 48 is made of a metal material, the ridge elements 48d and 48e may be formed by pressing. The sleeve member 48 is inserted to the through hole of the panel 38 from the outer display surface side thereof until the flange 48b is abutted thereagainst, as shown in Fig. 7. The sleeve member 48 may be inserted by pulling up same with a suitable tool engaged with the small opening 48c, if necessary. After the sleeve member 48 is inserted, the quick nut 50 is engaged with a portion of the sleeve body 48a projected from an inner surface of the panel 38. The quick nut 50 is substantially identical to the quick nut 26 shown in Figs. 2, 3 and 4. Thus, when the quick nut 50 is forcibly pressed over the sleeve body 48a, the four pawl elements of the quick nut 50 are firmly engaged with the outer surface of the sleeve body 48a, whereby the sleeve member 48 is prevented from dropping out of the through hole of the panel 38. The first and second ferrule members 52 and 54 are substantially identical to the ferrule member 28 shown in Figs. 2 and 3. Namely, each of the ferrule members 52 and 54 is made of a plastically deformable material such as a suitable metal or a suitable synthetic resin, and includes a tubular body 52a, 54a for receiving the optical fiber 40, 44 therein and a flange 52b, 54b integrally formed at one end thereof. Also, each of the tubular bodies 52a and 54a has a reduced thin portion 52a 1 , 54a 1 and an enlarged thick portion 52a 2 , 52a 2 integrated therewith, as best shown in Fig. 8. The reduced thin portion 52a 1 , 54a 1 is swaged by a suitable tool after the optical fiber 40, 44 is received in the ferrule 52, 54, so that the received optical fiber 40, 44 is immovably fixed within the tubular body 52a, 52a. Note, after the optical fiber 40, 44 is fixed in the ferrule member 52, 54, the end face of the optical fiber 40, 44 is treated, if necessary. The outer diameter of enlarged thick portion 52a 2 , 54a 2 is slightly smaller than the inner diameter of the sleeve body 48a, so that the ferrule members 52 and 54 can be inserted to the sleeve member 48 from the opposed end sides thereof, until the flanges 52b and 52b are abutted against the opposed ends of the sleeve member 48 as shown in Fig. 7. Nevertheless, the ferrule members 52 and 54 must be forcibly inserted in the sleeve member 48 because of the ridge elements 48d and 48e integrally formed on the inner wall surface thereof, whereby the inserted ferrule members 52 and 54 are firmly held in the sleeve member 48 by the engagement of the ferrule members 52 and 54 with the ridge element 48d and 48e, respectively. With the arrangement of the fixing device 46, the optical fibers 40 and 44 can be easily and quickly implanted in the panel 38 and thus the optical fiber display apparatus as shown in Fig. 6 can be advantageously assembled by use of the fixing device 22, especially on site. In the embodiment shown in Figs. 6, preferably, the optical fibers 44 suspended from the display panel 38 are constituted such that light can partially leak out of discrete locations on the surface of the optical fibers 44, whereby a decorative effect thereof can be increased. Figure 9 shows a decorative optical fiber which can be advantageously used as the optical fiber 44. This decorative optical fiber, generally indicated by a reference numeral 56, comprises a core 58 and a cladding 60 surrounding same, and is characterized in that a plurality of cone-shaped openings 62 are discretely formed over the surface thereof. A light conducted in the core 58 is allowed to partially leak out of the openings 62, and thus a decorative effect of the optical fiber 56 is increased. The decorative optical fiber 56 is not susceptible to breaking, due to the cone shape of the openings 62. Preferably, the decorative optical fiber 56 is made of suitable synthetic resin materials to enable an easy formation of the cone-shaped openings 62. Namely, the cone-shaped opening 62 can be easily formed by a penetraton of a heated needle element into the core 58, through the cladding 60. The cone-shaped openings 62 may be filled with a suitable transparent adhesive material 62, such as an ultraviolet-curing type adhesive, visible light-curing type adhesive, one-component type adhesive, two-component type adhesive or the like, as shown in Fig. 10, so that the decorative optical fibers 56 are strengthened against breakage. Preferably, the adhesive material 64 is made proud at the surface of the cladding 60, as shown in Fig. 10, so that the leaked light is scattered at the raised portion of the adhesive material 64, whereby the decorative effect is further increased. In the embodiment shown in Fig. 10, although the raised portion of the adhesive material 64 has a semi-spherical shape, it may have any other shape. Also, the adhesive material 64 may be colored by mixing a suitable dye therewith. Furthermore, lens elements may be inserted to the openings 62 and adhered thereto. In the embodiment shown in Fig. 9, although the openings 62 are diametrically disposed over the surface of the optical fiber 56, they may be disposed along the surface of the optical fiber 56 at one side thereof, as shown in Fig. 11. Note, the arrangement of the cone-shaped openings 62 can be carried out in various ways. For example, the openings 62 may be helically or circularly disposed on the surface of the optical fiber 56.

Claims: An optical fiber display apparatus (10; 36) comprising: a display panel (16; 38) having a plurality of through holes; a first plurality of optical fibers (18; 40), one end of each being optically connected to a light source (20A, 20B; 42C, 42D), and the other end thereof being implanted in said display panel from one surface side thereof; means (22; 46) for implanting the other end of each of said first plurality of optical fibers (18; 40) in said display panel (16; 38), said implanting means including a sleeve member (24; 48) detachably inserted and held in each of said through holes, and a first ferrule member (28; 32; 52) detachably inserted into said sleeve member from a side of one end thereof and held therein, the other end of each of said first plurality of optical fibers being received and fixed in said first ferrule member; characterized in that said apparatus further comprises: a second plurality of optical fibers (44; 56), one end of each being implanted in said display panel from the other surface side thereof, whereby said first plurality of optical fibers are optically connected to said second plurality of optical fibers at the end faces thereof, respectively, said second plurality of optical fibers being suspended from the other surface side of said display panel; and said implanting means (46) further comprises: a second ferrule member (54) for implanting the one end of each of said second plurality of optical fibers (44; 56) in said display panel, said second ferrule member being detachably inserted into said sleeve member (48) from a side of the other end thereof and held therein, the one end of each of said second plurality of optical fibers being received and fixed in said second ferrule member, each of said first and second ferrule members (52; 54) being connected to each other at the end surface thereof. An optical fiber display apparatus as set forth in claim 1, wherein each of said second plurality of optical fibers (44; 56) includes a core (58) and a cladding (60) surrounding said core, a plurality of cone-shaped openings (62) being discretely formed in the surface thereof so that a light conducted in said core is allowed to partially leak out of said cone-shaped openings. An optical fiber display apparatus as set forth in claim 2, wherein said cone-shaped openings (62) are filled with a transparent adhesive material. An optical fiber display apparatus as set forth in claim 3, wherein said adhesive material is made proud at the surface of the cladding (60), whereby the leaked light is scattered at the proud portion of said adhesive material. An optical fiber display apparatus as set forth in claim 1, wherein said implanting means further includes a quick nut (26; 50) for engaging with and fastening said inserted sleeve member (24; 48) to the panel, said quick nut being pressed onto said sleeve member from the one surface side of the panel. An optical fiber display apparatus as set forth in claim 1, wherein said first and second ferrule member (52; 54) are made of a plastically deformable material, and the fixing of the other end of each of said first plurality of optical fibers (40) in said first ferrule member (52) and the one end of each of said second plurality of optical fibers (44; 56) in said second ferrule member (54) is carried out by a partial swaging of said first and second ferrule members, respectively.

Inventors: HARATA YUKIO, KAWAI YOSHINORI, SHIBA TOSHINOBU, SHIMIZU SHOZO, SHIMOSHIMBARA YOSHIHIRO, UEDA YOSHIO, HARATA, YUKIO, KAWAI, YOSHINORI, SHIBA, TOSHINOBU, SHIMIZU, SHOZO, SHIMOSHIMBARA, YOSHIHIRO, UEDA, YOSHIO, Harata, Yukio, c/o Toyohashi Plants, Kawai, Yoshinori, c/o Toyohashi Plants, Shiba, Toshinobu, c/o Toyohashi Plants, Shimizu, Shozo, c/o Mitsubishi Rayon Company, Ltd., SHIMOSHIMBARA, YOSHIHIRO,, Ueda, Yoshio, c/o Mitsubishi Rayon Company, Ltd.
Applicants: MITSUBISHI RAYON CO, MITSUBISHI RAYON CO., LTD
Application year: 1991
Main classification: G09F9
IPC codes: G09F9, G02B6