JP2009205951A - Line illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a line illumination device with little degradation of brightness and with uniformity improved of irradiation light volume. <P>SOLUTION: The device is provided with: a line-type light guide (111) made up by forming a light-incident end by focusing optical fiber pieces (1) and attaching a focusing base (3) to them at one end of an optical fiber bundle (1A) bundling a plurality of the optical fiber (1) pieces, and a light-irradiating end by linearly aligning the optical fiber pieces (1) and attaching a case (2) including a line base at the other end of the optical fiber bundle (1A); and a light source device (7) emitting light toward the light-incident end. In adjacency to the light-irradiating end of the line-type light guide (111), a sheet-shaped light transmission body is arranged pinched by a transmission body holder (6) from either face side to be aligned with the light-irradiating end. The sheet-shaped light transmission body is provided with an incoming light end face opposed to the light-irradiating end of the line-type light guide (111) and an outgoing light end face at the opposite side, with the incoming light end face of the sheet-shaped light transmission body aligned with the light-irradiating end of the line-type light guide (111). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an illuminating device using an optical fiber, and more particularly to a line illuminating device suitably used for inspection of various products.

  As a line illumination device using an optical fiber, a device including a line type light guide and a light source device is provided. Here, the line type light guide forms an optical fiber bundle by bundling a plurality of optical fibers, condenses the optical fibers at one end of the optical fiber bundle, and forms a light incident end of the optical fiber bundle. Optical fibers are arranged in a line at the other end of the optical fiber bundle to form a light emitting end of the optical fiber bundle.

In order to make the amount of light emitted from such a line illumination device uniform, for example, in Japanese Patent Laid-Open No. 6-148442 (Patent Document 1), a light diffusing plate is provided at a distance from the line-shaped light emitting end of an optical fiber bundle. Further, it is disclosed that a hollow body having an inner reflection surface is provided between the line-shaped light emitting end and the light diffusion plate.
JP-A-6-148442

  However, in the method disclosed in Patent Document 1, a hollow region is interposed between the line-shaped light emitting end of the optical fiber bundle and the light diffusion plate, and reflection is caused by the inner reflection surface of the hollow body. Therefore, there is a problem that the brightness is reduced.

  In view of the above technical problems, an object of the present invention is to provide a line illumination device in which the decrease in brightness is small and the uniformity of the amount of irradiation light is improved.

According to the present invention, the above object is achieved as follows:
A light incident end is formed by converging the optical fiber at one end of an optical fiber bundle formed by bundling a plurality of optical fibers, and a light exit end is formed by aligning the optical fibers in a line at the other end of the optical fiber bundle. And a light source device that emits light toward a light incident end of the line light guide,
A sheet-like light transmission body aligned with the light emission end is disposed adjacent to the light emission end of the line-type light guide, and the sheet-like light transmission body is incident light facing the light emission end of the line-type light guide. A line illumination having an end face and a light exit end face opposite to the light entrance end face, wherein the light entrance end face of the sheet-like light transmitter and the light exit end of the line light guide are aligned. apparatus,
Is provided.

  In one aspect of the present invention, the sheet-shaped optical transmission body has a configuration in which the outer periphery of the core portion is covered with a cladding layer. In one aspect of the present invention, the sheet-shaped optical transmission body is formed by laminating a plurality of optical transmission unit sheets in which the outer periphery of the core portion is covered with the cladding layer. In one aspect of the present invention, the sheet-shaped optical transmission body has a curved cross-sectional shape orthogonal to the direction of the linear arrangement of the optical fibers at the light exit end of the line-type light guide. In one aspect of the present invention, the sheet-like optical transmission body is sandwiched by transmission body holders from both sides thereof.

  According to the line illumination device of the present invention, the light emitted from the light emitting end of the line-type light guide is guided from the light incident end surface of the sheet-like light transmission body into the sheet-like light transmission body, where it is efficiently performed. The line illumination light is transmitted while being repeatedly reflected on the inner surface and emitted from the light exit end face, thereby obtaining bright line illumination light with improved uniformity of the amount of irradiation light.

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

  FIG. 1 is a schematic diagram showing a configuration of an embodiment of a line illumination device according to the present invention, FIG. 2 is a schematic partial bottom view thereof, and FIG. 3 is a schematic longitudinal sectional view of a sheet-like optical transmission body. FIG. 4 is a schematic bottom view of the light transmission unit sheet.

  An optical fiber bundle (1A) is formed by bundling a plurality of optical fibers (1). As the optical fiber (1), a known organic or inorganic optical fiber can be used. At one end of the optical fiber bundle (1A), the light incident end is formed by converging the optical fiber (1) in a circular shape. A focusing base (3) is attached to the light incident end. At the other end of the optical fiber bundle (1A), the light emitting ends are formed by aligning the optical fibers (1) in a line (aligned in the left-right direction in FIG. 1). At the light emitting end, the light emitting end face of each optical fiber (1) is disposed downward in FIG. At the light exit end, the optical fibers (1) may be arranged in one row, but may be arranged in multiple rows, for example, 2 to 4 rows as appropriate, depending on the illumination design.

  In order to maintain the arrangement of the optical fibers (1) at the light exit end, a housing (2) is attached to the light exit end. A housing | casing (2) consists of a line cap and a side plate. The line cap engages with the tip of the optical fiber (1) to ensure its line-like arrangement, and the side plate holds the line cap and protects the light emitting end of the optical fiber bundle and the vicinity thereof appropriately. It is to be stored. The housing (2) is formed in a box shape using a lightweight and highly rigid aluminum plate in consideration of ease of attachment to the apparatus. Between the housing (2) and the focusing base (3), the optical fiber bundle (1A) is protected by a flexible protective tube (protective flexible tube) (4) for preventing damage. The line type light guide (111) is configured as described above.

  A light source device (7) is disposed adjacent to the light incident end of the line type light guide (111). The light source device (7) includes a light source (8) made of a halogen lamp or the like, and emits light toward the light incident end of the line type light guide (111).

  Adjacent to the light emitting end of the line type light guide (111), a sheet-like light transmission body (5) aligned with the light emitting end is disposed. The sheet-shaped light transmission body (5) includes a light incident end face (upper end face in FIG. 1) facing the light emitting end of the line type light guide (111) and a light exit end face opposite to the light incident end face (lower face in FIG. 1). End face). The light incident end face of the sheet-like light transmission body (5) and the light emitting end face of the line type light guide (111) both extend in the left-right direction in FIG. 1 and are aligned with each other. In the sheet-like optical transmission body (5), the distance, that is, the length between the light incident end face and the light outgoing end face is L.

  The sheet-like optical transmission body (5) may be composed of one optical transmission unit sheet in which the outer periphery of the core portion (10) as shown in FIG. 4 is covered with the cladding layer (11), or such A plurality of such light transmission unit sheets, for example, 2 to 4 sheets (including simple superposition) may be laminated. The number of laminated light transmission unit sheets can be appropriately selected according to the lighting design. The sheet-like light transmission body (5) can be made as thick as the light emitting end of the line-type light guide (111), but if it is made thicker by about 1 mm, the line-type light guide ( 111) Even if an axial shift occurs between the light emitting end of 111) and the light incident end face of the sheet-like light transmission body (5), light can be efficiently taken into the sheet-like light transmission body (5). Therefore, it is preferable.

  The core part (10) and the clad layer (11) of the light transmission unit sheet can be made of a synthetic resin. Examples of such a synthetic resin include a methyl methacrylate copolymer (PMMA), a polystyrene resin, A known material such as a fluorinated methacrylate polymer or a vinylidene fluoride polymer can be used, and a combination of materials capable of obtaining a required refractive index difference between the core (10) and the clad layer (11). Is used.

  The sheet-like optical transmission body (5) is sandwiched by the transmission body holder (6) from both sides thereof. The transmitter holder (6) maintains a linear arrangement of the sheet-like optical transmitter (5), and is lightweight and highly rigid in consideration of external protection and connection with the line-type light guide (111). It can be formed into a box shape with an aluminum plate.

  The sheet-like optical transmission body (5) has a straight shape in which the cross-sectional shape perpendicular to the direction of the linear arrangement of the optical fibers (1) at the light exit end of the line-type light guide (111) is straight as shown in FIG. However, as shown in FIG. 5, it may be curved in an S shape, for example. When it is curved into an S shape or the like, the uniformity of the amount of irradiation light is further improved, but the amount of irradiation light tends to decrease due to light leakage. The degree of bending is preferably at least displaced more than the thickness of the core (10). The number of bends is two in the case of an S-shape, but other suitable numbers are possible. Whether or not to bend, and how much and how many times to be bent may be appropriately set according to the lighting design.

  When the cross-sectional shape is a straight shape (FIG. 3), the length L of the sheet-like optical transmission body (5) is preferably 30 mm or more because it tends to impair the uniformity of the amount of irradiated light when it is shortened. . The length L of the sheet-like optical transmission body (5) is uniform even when the cross-sectional shape is curved in an S-shape (FIG. 5), even if it is shorter than the straight shape. It tends to be less likely to impair the performance, so it can be made shorter.

  The line illumination device of the present invention can be manufactured, for example, by the following method.

  After a long optical fiber is wound around a dedicated drum and arranged in a sheet shape, the optical fiber is temporarily fixed using a tape so as not to break the sheet-like arrangement. The temporarily stopped optical fiber is cut at a predetermined position, and the optical fiber sheet (optical fiber bundle) obtained thereby is removed from the drum.

  After bonding one end edge of the optical fiber sheet corresponding to one end face of each optical fiber to the line cap to form a light emitting end in a line arrangement, the end face of the optical fiber at the light emitting end is waterproofed. Mirror finish using paper. Next, the light emitting end of the optical fiber bundle bonded and fixed to the line cap is attached to the housing side plate and stored.

  Next, the optical fiber bundles coming out of the housing are randomly converged, and the optical fibers are firmly fixed together by heat fusion, and then the protective flexible tube is fixed to the optical fiber bundle, and the concentrating base is fixed, and then the optical fiber bundle is fixed. The light incident end is formed. Thereafter, the light incident end face of the optical fiber bundle is optically polished using water-resistant paper.

  A line type light guide is obtained as described above.

  On the other hand, the sheet-like optical transmission body is bonded to the transmission body holder, and the end surface is mirror-finished using water-resistant paper.

  Next, the line-type light guide and the sheet-like optical transmission body with the transmission body holder are arranged in a required positional relationship, connected as desired, and optically coupled to obtain a line illumination device.

  Examples will be described in detail below.

  The line lighting device of the present invention was manufactured by the following method.

  An optical fiber sheet having a width of 300 mm, consisting of a number of optical fibers having a length of 2 m, is obtained by winding a long optical fiber having a diameter of 0.5 mm around a dedicated drum having a circumference of 2 m, temporarily fixing it, and cutting it at a predetermined position. Two sheets were made.

  Next, an aluminum line cap having an outer shape of 350 mm × 20 mm and a thickness of 5 mm was prepared. After fixing the optical fibers (1) of the two optical fiber sheets with an adhesive so as to be sandwiched between the line caps, The light exit end face was finished by optical polishing of the light exit end. Next, the light emitting end of the optical fiber sheet [optical fiber bundle] (1A) bonded to the line cap was fixed to the side plate and stored in the housing (2).

  After the optical fiber bundle (1A) coming out of the housing (2) is randomly focused, the optical fibers are firmly fixed by heat fusion, and the optical fiber bundle (1A) is passed through the protective flexible tube (4). It was fixed to the focusing base (3) by adhesion. Thereafter, the light incident end face of the optical fiber bundle (1A) to which the focusing base (3) was attached was optically polished using water-resistant paper to produce a 300 mm wide line light guide (111).

  Next, an optical transmission body (5) obtained by superposing four optical transmission unit sheets having a width of 300 mm, a length of 65 mm, and a thickness of 0.3 mm and having a straight cross-sectional shape was prepared.

  Next, an aluminum transmitter holder (6) having a width of 350 mm, a length of 60 mm, and a thickness of 20 mm is prepared, and the optical transmitter is fixed with an adhesive so as to be sandwiched between the transmitter holders. The output end face was optically polished to finish the end face, and the line type light guide (111) and the optical transmission holder (6) were connected to produce a line illumination device.

  A lighting device was manufactured in the same manner using a light transmission unit sheet having a S-shaped cross section.

  Here, a line illumination device (abbreviated as “optical transmission body”) using the light transmission body of the straight cross-sectional shape of the present invention and a line illumination using the light transmission body of the cross-sectional shape curved in the S shape of the present invention. Line illumination using a device (abbreviated as “S-shaped light transmission body”), a conventional line illumination device using a diffuser plate (abbreviated as “conventional method”), and a conventional line type light guide having no diffusion function The irradiation light quantity of the apparatus (abbreviated as “line type light guide”) was compared. As a measurement method, a φ1 mm photometer was placed 20 mm away from the line-shaped emission end face of the apparatus, and the illuminance was measured by scanning the center of the line in the thickness direction from the right end to the left end in the longitudinal direction. FIG. 6 is a graph showing the measurement result of the irradiation light amount group.

  Based on the MAX value and the MIN value of the light amount in the line width, the average light amount and the light amount unevenness calculated by the formula of (MAX−MIN) / (MAX + MIN) × 100% were compared for the above line illumination devices. The results shown in Table 1 were obtained. That is, in the example of the present invention, brighter and more uniform line illumination was obtained than in the conventional example.

It is a schematic diagram which shows the structure of one Embodiment of the line illuminating device which concerns on this invention. It is a typical partial bottom view of the line illuminating device of FIG. It is a typical longitudinal cross-sectional view of the sheet-like optical transmission body of the line illuminating device of FIG. It is a typical bottom view of the light transmission unit sheet | seat of the line illuminating device of FIG. It is a typical longitudinal cross-sectional view of the sheet-like optical transmission body in other embodiment of the line illuminating device which concerns on this invention. It is a graph which shows the measurement result of the irradiation light amount spot of a line illuminating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber 1A Optical fiber bundle 2 Case 3 Focusing cap 4 Protective flexible tube 5 Sheet-like optical transmission body 6 Transmission body holder 7 Light source device 8 Light source 10 Core part 11 Cladding layer 111 Line type light guide

Claims (5)

A light incident end is formed by converging the optical fiber at one end of an optical fiber bundle formed by bundling a plurality of optical fibers, and a light exit end is formed by aligning the optical fibers in a line at the other end of the optical fiber bundle. And a light source device that emits light toward a light incident end of the line light guide,
A sheet-like light transmission body aligned with the light emission end is disposed adjacent to the light emission end of the line-type light guide, and the sheet-like light transmission body is incident light facing the light emission end of the line-type light guide. A line illumination having an end face and a light exit end face opposite to the light entrance end face, wherein the light entrance end face of the sheet-like light transmitter and the light exit end of the line light guide are aligned. apparatus.   The line illumination device according to claim 1, wherein the sheet-like optical transmission body has a configuration in which an outer periphery of a core portion is covered with a clad layer.   The line illumination device according to claim 2, wherein the sheet-like optical transmission body is formed by laminating a plurality of optical transmission unit sheets in which an outer periphery of the core portion is covered with the cladding layer.   The sheet-like optical transmission body is characterized in that the shape of a cross section perpendicular to the direction of the linear arrangement of the optical fibers at the light exit end of the line-type light guide is curved. The line illuminating device as described in any one.   The line illumination device according to any one of claims 1 to 4, wherein the sheet-like optical transmission body is sandwiched by transmission body holders from both sides thereof.