JPH0746920Y2 - Lighting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a lighting device, and more particularly to a lighting device in which the amount of emitted linear light is increased.

[Conventional technology]

An illuminating device using an optical transmission rod such as a quartz glass rod or an optical glass rod is disclosed in Japanese Patent Application Laid-Open No. 60-118806 or Japanese Patent Application No. 60-284115 by the applicant (Japanese Patent Application Laid-Open No. 62-142465).
Have been proposed in.

In this illuminating device, a schematic configuration of a main part is shown in FIG. 8. However, the solid cylindrical optical transmission rod 1 has a higher refractive index than the rod 1 and is light resistant. Diffusion stripes 2 are formed by applying a certain fine powder in the form of straight fine stripes. As the fine powder, titania, magnesia, barium sulfate or the like can be appropriately used. A lamp 3 having a lamp reflecting mirror 3a composed of a spheroidal reflecting mirror is arranged at a position where one end surface 1a of the rod 1 formed in a flat shape faces each other, and the light emitted from the lamp 3 is , Is injected into the rod 1. On the other end surface 1b of the rod 1, a plane reflecting mirror 4 having a reflecting surface on the surface facing the end surface 1b is arranged.

In the above configuration, when the lamp 3 is turned on, the lamp 3
The emitted light is incident on the end surface 1a of the rod 1 while being condensed directly or via the lamp reflecting mirror 3a. The incident light is transmitted in the axial direction while repeating total reflection, and is transmitted to the terminal surface 1b of the rod 1. The light transmitted to the terminal surface 1b of the rod 1 is reflected inside the rod 1 by the flat reflecting mirror 4. At this time, the light that has reached the diffusion fringes 2 is diffused and reflected, and the light having directivity is emitted to the side facing the diffusion fringes 2, and the linear light can be emitted to the outside of the rod.

[Problems to be solved by the invention]

However, according to the illuminating device described above, when the light emitted from the lamp 3 enters the rod 1 from the end face 1a and is transmitted, the traveling angle of the transmitted light decreases from the angle of incidence on the rod 1. Therefore, there is a problem that the light emitted from the lamp 3 cannot be effectively converted into linear light.

[Means and Actions for Solving Problems]

The present invention has been made in view of the above, and improves the efficiency of converting light emitted from the lamp 3 into linear light and improves the light amount level of the linear light emitted. The present invention provides an illuminating device in which the end face of the light incident side is a convex face projecting to the incident light source side.

〔Example〕

Hereinafter, a lighting device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment according to the present invention, and since the same parts as those in FIG. 8 are shown by the same reference numerals, overlapping description will be omitted, but the end face of the light transmission rod 1 on the incident side is the lamp 3. A convex surface (hemispherical convex surface) 10 protruding in a hemispherical shape toward the side is formed. In order to form the convex surface 10, when a quartz rod is used as the rod 1, the rod 1 is made vertical and rotated about an axis, and the end face of the rod 1 is melted by an acid / hydrogen flame from below. Form. Also, in the case of a multi-component glass rod, it can be formed in the same manner as in the case of a quartz glass rod. Further, when a resin rod is used as the rod 1, the end surface may be formed into a hemispherical surface to form the convex surface 10 by molding, injection molding, thermal processing, or the like.

In the above structure, when the lamp 3 located at the first focal point of the reflecting mirror 3a is turned on, the light emitted from the lamp 3 is incident on the end surface 1a of the rod 1 either directly or through the lamp reflecting mirror 3a while being condensed. To be done.

A lamp 3 incorporating a lamp reflector 3a when it is incident
As shown in FIG. 2, the light emitted from the lamp is focused light A which is reflected light by the lamp reflecting mirror 3a, and parallel light B and divergent light C which are emitted from the opening of the lamp reflecting mirror 3a as direct light from the lamp 3. It is divided into three types of light flux components. Of these, the focused light A is a light flux component that is condensed from the first focus to the second focus of the lamp reflecting mirror 3a, and most of the solid angle of the lamp (compared to the linear light composed of the divergent light B and the parallel light C ( Since it covers about 70%), it is the strongest part of energy. When the focused light A is incident on the flat end face 1a, as shown in FIG. 3 (b), an incident loss occurs due to Fresnel reflection on the end face 1a, and the material of the rod 1 and the air refraction Since the traveling angle of the transmitted light flux decreases from the incident angle due to the difference with the index, the number of total reflections within the rod 1 also decreases. For this reason, the transmitted light flux reaching the diffusion fringes 2 is reduced, and the emission light amount level of the linear light emitted to the outside of the rod 1 is low. On the contrary, in this embodiment, since the end face is the convex surface 10 having a hemispherical shape, as shown in FIG. If it is designed to pass through the central axis, it will propagate at the same angle as the incident angle. Therefore, the number of total reflections in the rod 1 is about 2.5 times that of the conventional lighting device having the end face 1a, and the transmitted light flux reaching the diffusion fringes 2 increases, so that the line radiated to the outside of the rod 1 is increased. The efficiency of the emitted light of the circular light is improved and the amount of emitted light becomes high. Furthermore, since the incident angle of the light from the lamp 3 of the rod 1 to the convex surface 10, which is the incident surface, is substantially vertical, Fresnel reflection at the incident end face is reduced and incident loss is also reduced.

As described above, the focused light A occupies about 70% of the light radiated toward the rod 1, but the remaining about 30% is emitted as linear light from the lamp 3 from the opening of the lamp reflecting mirror 3a. Become. Since the direct light is a divergent light beam from the filament position of the lamp 3, the rate of incidence on the rod 1 is slightly different depending on the distance between the lamp 3 and the incident end face of the rod 1 and the diameter of the rod 1, but Although it is a small effective incident component, it contributes as a light flux component reaching the diffusion fringes 2 like the focused light A. That is, the parallel light B is an incident component of the direct light in the vicinity of the center of the optical axis and is substantially parallel to the optical axis. As shown in FIGS. 4 (a) and 4 (b), the incident light flux does not reach the diffusion fringes 2 when it is incident on the end face 1a, but when it is incident on the convex surface 10, the parallel light B is refracted to be a focused light. Will propagate through the rod 1 and can reach the diffusion fringes 2. Therefore, it is possible to increase the output light amount level of the light radiated to the outside of the rod 1.

The divergent light C is direct light from the lamp 3 which is incident on the outer peripheral portion of the end surface of the rod 1 at a relatively gentle divergence angle. Therefore, due to the refraction at the incident surface, there is a difference in the propagation direction as shown in FIGS. 5 (a) and 5 (b) based on the difference between the flat end surface 1a and the convex surface 10 of the incident side end surface of the rod 1. However, there is practically no difference in the components reaching the diffusion fringes 2.

The light thus entering the rod 1 is transmitted in the axial direction while repeating total reflection, and the end surface 1b of the rod 1 is
Transmitted up to. The light transmitted to the terminal surface 1b of the rod 1 is reflected inside the rod 1 by the flat reflecting mirror 4.

The reflected light is again reflected by the convex surface 10 toward the diffusion fringes 2 as shown in FIGS. 6 (a) and 6 (b). That is, when the critical angle of the rod 1 in the air atmosphere (43.23 ° when the material of the rod is quartz is 43.) is α _c , the component close to parallel light is D and D in FIG. As shown by E, in the region of α ≧ α _c , total reflection occurs at the interface, and it is returned to the rod 1 again.
This component reaches the diffusion stripe 2. In the region of α <α _c , as shown by F, the component is refracted from the interface to the outside and transmitted as focused light, and the component is returned to the rod 1 again by Fresnel reflection at the interface. The component returned to 1 reaches the diffusion fringe 2. As for the components other than the parallel light, the Fresnel reflection component at the interface is returned to the rod 1 again and reaches the diffusion fringes 2 as shown in FIG. 6 (b).

As described above, while the light flux incident from the convex surface 10 reaches the diffusion fringes 2 while reaching the plane reflecting mirror 4, the fringes are reflected by the plane reflecting mirror 4 and reciprocate in the rod 1. 2 and then reflected by the convex surface 10 to reach the diffusion stripe 2. The light that reaches the diffusion fringes 2 by this repetition is diffused and reflected, and the light having directivity is strongly emitted to the side facing the diffusion fringes 2, and the linear light having an extremely large light amount level is emitted to the outside of the rod 1. Is emitted.

In addition, when the applicant conducted an experiment, a flat end face 1a
Compared with the case of No. 1, when the hemispherical convex surface 10 is formed, as shown in FIGS. 7 (a) and (b) and Table 1, the amount of light emitted from the rod 1 is extremely increased. It was confirmed to do.

However, the average value of the amount of light on the flat end face 1a was set to 100%, and the light emitted from the rod having the diffusion fringes of 230 mm was measured at 2 mm intervals.

In the present embodiment, the convex surface 10 is formed in a hemispherical shape, but it is not limited to this, and although not particularly shown, the end surface may be formed in a convex shape with respect to the incident side. Of course, it may be a semi-elliptical spherical surface or a tapered shape.
Also with these, the incidence efficiency of the light flux from the light source into the rod 1 can be improved.

[Effect of device]

As described above, according to the lighting device of the present invention, the reflected light from the concave reflecting mirror made of the spheroidal surface passes through the center of the hemispherical convex spherical surface when entering the end face of the optical transmission rod. The light enters without refraction, almost no Fresnel reflection occurs, and the incident loss is reduced.

In addition, the incident light has a large propagation angle within a range not exceeding the critical angle and propagates at an angle substantially the same as the incident angle, which increases the chance of reflection at the diffusion fringes. Therefore, the propagating light flux is effectively converted into linear light, and the light amount increases.

Further, when the surface area of the incident end is a hemispherical surface, it is twice as large as the cylindrical cross-sectional area, the apparent incident cross-sectional area is increased, and the heat load per unit area and the incident light flux density are made uniform.

[Brief description of drawings]

FIG. 1 is a partially longitudinal explanatory view showing an embodiment according to the present invention,
FIG. 2 is an explanatory view of a light beam incident on the rod, and FIG. 3 (a)
(B) is an explanatory view of the incident state of focused light, FIG. 4 (a)
FIG. 5B is an explanatory view of the incident state of parallel light, FIG.
(B) is an explanatory view of the incident state of divergent light, FIG. 6 is an explanatory view showing the effect of the convex surface on the reflected light from the end surface of the rod, FIG. 7 is a graph showing the experimental results, and FIG. 8 is It is a schematic explanatory drawing which shows the conventional illuminating device. Explanation of symbols 1 ... Rod, 1a ... End face, 1b ... End face, 2 ... Diffusing fringe, 3 ... Lamp, 3a ... Lamp reflector, 4 ... Plane reflector, 10 ... Hemispherical convex surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junji Nakamura 69 Otomon, Ogata, Yamagata City, Yamagata Prefecture (72) Inventor Fukunishi Ko, Tanabe, Sagamihara City, Kanagawa Prefecture 2634-15 (56) References JP-A-59-81683 ( JP, A) JP 61-77802 (JP, A) JP 57-138610 (JP, A) JP 61-113012 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. An optical transmission rod having diffusion fringes formed on the outer peripheral surface thereof by adhering fine powder having a high refractive index in the form of linear fine stripes in the axial direction, and disposed on one end face of the optical transmission rod. A light source device having a concave reflecting mirror made of a spheroid that makes light incident on one end face thereof, and an illumination device having a flat reflecting mirror at the other end face of the light transmission rod, wherein the light source of the light source device is It is arranged at the position of the first focal point of the ellipse forming the spheroid, and the one end face of the optical transmission rod is formed in a hemispherical convex surface toward the light source device side, and the spherical center position of the hemispherical convex surface. Is arranged so as to match the position of the second focal point of the ellipse, so that the reflected light from the concave reflecting mirror is incident on the hemispherical convex surface of the transmission rod in a direction perpendicular to the hemispherical convex surface. Made lighting equipment.