JPH0843637A - Light distribution structure of parallel incident light - Google Patents

Abstract

PURPOSE:To lessen the reflection loss at end faces to the min. limit and to prevent overheating of the light receiving end of a light guide by connecting this light guide concentrically to an optical rod. CONSTITUTION:The luminous flux emitted from a light source 5 existing on one side P1 of two pieces of focuses P1, P2' is reflected by a reflector 31a, made incident on the optical rod 32a from its side face, condensed at the other focus P2', passed through the other focus P2' by intersecting therewith, reflected by a reflection film 32a2 formed at the paraboloid 32a1 of revolution of at the front end, and so reflected as to be made into the luminous flux parallel with the central axis of the optical rod 32a. As a result, the parallel luminous fluxes are made incident at incident angle 0 on the light receiving surface of the light guide 22c and the reflection loss at the end face is lessened to the min. limit. Further, the structure is hermetically closed by the reflector 31a and the light guide 22c is not projected into the space arranged with the light source 5. The structure is so formed that the optical rod 32a receives the light and that this light is guided to the light guide 22c and, therefore, there is no possibility of overheating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for distributing light emitted from a single light source to a plurality of light guides and guiding the light to a lamp by each of the plurality of light guides.

[0002]

2. Description of the Related Art As a technique for distributing a light beam emitted from a single light source to a large number of light guides and guiding it to a lamp, Japanese Patent Application Laid-Open No. HEI-2 is proposed.
A centralized illumination system using a high-brightness light source described in Japanese Patent Publication No. 172102 is known. FIG. 4 shows the above known example.
The special bulb 1 shown in FIG. 1A is made of hard glass, and the discharge light emitting mechanism is enclosed in the special bulb 1 and is fed by the lead wires 1a and 1b. There are many (5 in this example) in this special bulb 1.
Light guides 1c to 1g are formed, and the light generated by the discharge is distributed and led out by these light guides. As shown in FIG. 1B, a large number of light guides 1
The light derived from c to 1 g is the optical fiber 2c.
.About.2g lead to the lamps 3c to 3g, respectively (the lamps 3d and 3e are not shown in the figure). In the above-mentioned known example, the special tube 1 is required, and this member is not versatile, which is inconvenient for practical use. To eliminate these inconveniences,
A configuration of FIG. 5 is also proposed in which a commercially available light source bulb can be used. The light source 5 is installed at the focus F of the rotary parabolic mirror 4 shown in FIG. This light source 5
For example, a commercially available mercury discharge lamp can be used, and it can be attached / detached and replaced. Light incident on the paraboloidal mirror 4 from the light source 5 is reflected parallel to the optical axis Z as indicated by arrows a, b, and c. A large number of optical fibers 6 are arranged so as to face the parallel light fluxes, and the respective light fluxes are incident and guided to desired locations (lamps not shown). 7 is a glass rod for absorbing heat rays.

In the prior art shown in FIG. 5, the parallel luminous flux reflected by the rotating parabolic mirror 4 has a uniform luminous flux distribution density. Therefore, a large number of optical fibers 6 are evenly distributed in the amount of light. Depending on the application of this light distribution mechanism, the above-mentioned uniform distribution function may be convenient, but it is not suitable for unifying the light source of a vehicle lamp, for example.
Generally, a vehicle is equipped with a large number of lamps, a headlight and a stop lamp require a relatively large amount of light, and a tail lamp and a small lamp require a small amount of light. Therefore, if the conventional example of FIG. 5 is applied to a vehicular lamp and the light emission of the light source 5 is evenly distributed, the headlamps and the stop lamps lack the light amount supplied, and the tail lamps and the small lamps supply the light amount. Is too large, there is a problem that the light must be dimmed by the optical filter. A light distribution structure shown in FIG. 6 is conceivable as a light distribution structure capable of intentionally distributing the light amount to a large number of light guides by solving the above-mentioned problems. This structure was created by the present inventors and will be referred to as a tentative plan hereinafter. FIG. 6 (A) is a side view, and FIG. 6 (B) is a BB arrow view thereof. 8 is a spheroidal mirror, f ₁ is its first focal point, f ₂ is also its second focal point, Z
Is also the optical axis. The light source 5 is arranged near the first focal point. In this proposal, the light source was composed of a mercury discharge tube.

The spheroidal mirror 8 is emitted from the light source 5 described above.
The light flux reflected at is focused on the second focal point f ₂ as shown by arrows d and e, intersects, and then diffuses. A convex lens 9 is provided at a position for receiving the diffused light, and the light is condensed to form a parallel light flux as indicated by arrows d'and e '. A convex lens having such a function is widely used as an aspherical convex lens for a projector-type headlight, for example. Since FIG. 6A is vertically symmetrical with respect to the optical axis Z, the arrow mark is attached to only one side. A large number of light guides 6 are arranged so as to face the parallel light beams d'and e '. The BB arrow view is as shown in FIG. The distribution density of the parallel light flux is dense in the central portion and sparse in the peripheral portion. By using this, a light guide that guides light to a large amount of light such as a headlight or a stop lamp is arranged in the center as shown in 6a of FIG. 6B, and a small amount of light such as a small lamp or a tail lamp is arranged. The light guide for guiding the light to the lamp is arranged at the peripheral portion as shown in 6b of FIG. Accordingly, it is possible to distribute light to each of the lamps without excess or deficiency. Also, FIG.
In the prior art shown in (1), when the number of optical fibers 6 to be arranged is increased, the rotary parabolic mirror 4 is replaced with one having a large diameter to increase the diameter of the parallel light flux (arrows a, b, c). Although it had to be done, in the trial shown in FIG. 6A, the convex lens 9 is replaced with a large diameter lens without moving the spheroidal mirror 8 and the large diameter lens is moved forward of the lamp. Since the diameter of the parallel light flux (arrows d ', e') increases, the number of light guides 6 arranged can be increased.

The light distributing device according to the tentative plan shown in FIG. 6 has an excellent effect that the number of the light guides 6 arranged can be easily changed, but the convex lens 9 is a relatively heavy component member. In addition, the convex lens 9 absorbs light and causes a loss due to surface reflection of light. Comparing the problems of the conventional example shown in FIG. 4, the known example shown in FIG. 5 and the trial example shown in FIG. 6, the conventional example shown in FIG. 4 uses a special bulb, so that it is not easy to replace the light source bulb. In the known example of FIG. 5, it is not easy to change the number of light guides to be installed, and the tentative plan of FIG. 6 is heavy because a convex lens is provided. In order to solve the above problems, a light distribution structure as shown in FIG. 7 has been proposed and is well known.
The structure shown in FIG. 7 is a device created by the present inventor and applied for separately (actual application No. 4-55689, hereinafter referred to as a device of the prior application). FIG. 6 is a perspective view corresponding to one example of a light distribution structure according to the present invention. A pair of spheroidal mirrors 8A and 8B are opposed to each other and fixed to each other. In this example, it is fixed with a mounting screw 8C via a short cylindrical adapter 12. The light source 5 is installed in the space surrounded by the pair of spheroidal mirrors 8A and 8B. In this example, a discharge lamp burner was used as the light source. Reference numeral 10 drawn by a solid line is a socket of the light source 5. The light source socket may be provided at the position 10 'shown by the phantom line.
Reference numeral 11 is a power supply harness. The light receiving portions of a plurality of (five in this example) light guides 9a to 9d fixed to the short cylindrical adapter 12 are arranged radially at equal intervals in the circumferential direction. Each of these light guides is connected to a lamp (not shown). Z is a spheroidal mirror 8A,
It represents the optical axis of 8B. The light emitted from the light source 5 is
In the space surrounded by the pair of spheroidal mirrors 8A and 8B repeatedly and surrounded by the pair of spheroidal mirrors 8A and 8B, light in all directions is distributed with a uniform luminous flux density. (Speaking figuratively, this space is filled with light). Therefore, equal light amounts are derived from the light guides 9a to 9b. Since this embodiment (FIG. 7) is substantially symmetrical with respect to the optical axis Z, the light distribution amount of each light guide becomes uniform with high accuracy. Further, as can be easily understood from this operation, the number of light guides to be installed can be set arbitrarily, and the degree of freedom in design is large. Also,
When the light source (for example, a discharge lamp) is worn, the mounting screw 8C can be removed and replaced easily. Further, as is apparent from this embodiment, since no convex lens is used, the weight can be reduced. As described above, the invention of the prior application shown in FIG. 7 is a recent and most advanced publicly known technology relating to the light distribution structure, and (a) is lightweight because it does not use a convex lens. ) Light emitted from a single light source can be distributed to multiple light guides, and (c) the number of light guides can be set arbitrarily, and (d) the amount of light for each light guide. Is evenly distributed.

The inventors of the present invention applied for the optical distribution structure according to the invention of the prior application shown in FIG. 7, and then continued the practical application test and research to find that the desired effect was obtained in practical use. I confirmed, but I found that there is room for improvement in the following points and confirmed this. That is, although there are various types of optical fibers forming the light guide, one of the optical characteristic values of each type of optical fiber is the critical angle of the incident angle on the light receiving surface.
Incident light that exceeds this critical angle may be totally reflected by the light-receiving surface, or may not be guided in a correct state even if it enters the optical fiber. In the invention of the prior application (FIG. 7), since the incident angle of the light incident on the light receiving surfaces of the light guides 9a to 9e could not be controlled, the light having the incident angle exceeding the critical angle could not be effectively derived. There was a limit to the improvement of the effective utilization rate of the luminous flux. Further, in the prior art shown in FIG.
A light flux emitted from the light source 5 and not incident on the spheroidal mirror 8 (a light flux emitted in the range of the solid angle ω shown in FIG. 6) is not effectively used, so that the luminous flux effective utilization rate of the entire light distribution structure is not high. The configuration shown in FIG. 8 is effective for eliminating the above-mentioned problems and improving the effective utilization rate of the light flux. This configuration is an unknown "light distribution structure with an auxiliary reflector" created by the present inventors and applied for separately.
(Japanese Patent Application No. 6-140428), which is hereinafter referred to as the invention of the prior application.

Next, referring to FIGS. 8 to 10, an embodiment of the previously-noted prior invention will be described. FIG. 8 shows a light distribution structure provided with an auxiliary reflector according to the invention of the prior application, and is a view in which an optical path arrow is added to a cross-sectional view schematically illustrating a main part. For convenience of explanation, orthogonal coordinate axes Y and Z are assumed as shown. 21a and 21b are spheroidal reflectors each having a first focal point P ₁ and a second focal point P ₂ ,
The first focal points P ₁ are arranged in series so as to coincide with each other, and the second focal points P ₂ are positioned on the axis Z, respectively. That is,
The axis Z coincides with the major axis direction of the ellipse. Illustrated A
Is the major axis dimension, and B is the minor axis dimension. The light guides 22a and 22b are installed along the extended line of the major axis of the spheroidal reflector, that is, on the Z axis. Between the first focal point P ₁ and the second focal point P ₂ , concave mirror type auxiliary reflectors 23a and 23b direct their convex surfaces toward the first focal point, that is, their reflective surfaces direct toward the second focal point P ₂ . At the same time, they are arranged toward the light receiving surfaces of the light guides 22a and 22b. The above-mentioned auxiliary reflectors 23a, 23
b re-reflects the light flux passing through the second focal point toward the light receiving surfaces of the light guides 22a and 22b so that the incident angle θ ₁ is less than half the critical angle. In carrying out the present invention, the incident angle of the re-reflected light is required to be 1/2 or less of the critical angle, and the incident angle θ ₁ is 0 <2θ ₁ <critical angle .... (1) It is allowed to change within the range of the above formula (1).
The incident angle cannot be 0 or less, and the fact that the incident angle is half or less of the critical angle is indispensable for achieving the object of the present invention. Therefore, the numerical limitation of the above formula (1) is theoretical. It is based on grounds. This permissible angle range is quite wide from the viewpoint of precision optics. That is, for example, when the optical fiber is made of quartz glass and the critical angle is about 15 degrees, it has a wide allowable range of 0 ° <θ ₁ <7.5 ° (2). Therefore, the shapes of the auxiliary reflectors 23a and 23b such that the incident angle θ ₁ of the re-reflected light shown in FIG. 1 falls within the range of the above-mentioned formula (2) specify this by an analytical geometric formula. The fact is that
It is extremely difficult, and according to modern optical technology, "a light beam re-reflected by an auxiliary reflector is incident on the light-receiving surface of the light guide at an incident angle of less than half the critical angle,
The shape of the reflection surface of the "auxiliary reflector" can be configured in any way, and is a matter of design consideration. The auxiliary reflector of this embodiment was designed by the following design so that the incident angle of the re-reflected light incident on the light guide would be an angle θ ₁ ′ smaller than the critical angle. 9A and 9B are charts showing a design procedure for obtaining the three-dimensional shape of the auxiliary reflector in FIG. 8 described above, in which FIG. 9A shows a reference curve of interest on the Z axis, and FIG. 9B shows rotation of the Z axis. (C) represents a method of converting the coordinates into a shape to obtain the line segment M ', and (C) represents a method of rotating the above-mentioned line segment M'about the axis Z to obtain a rotation surface constituting the reflection surface. ing. As shown in FIG. 9A, a line segment M consisting of a parabola with the axis Z as the axis and the second focus P ₂ as the focus position is determined. As shown in FIG. 9 (B), with respect to the second focal point P ₂ , the line segment M is angled by θ ₁ ′.
Just rotate. The axis Z ′ shown in the drawing is the angle θ ₁ ′ with respect to the axis Z.
The figure shows the shape when it is rotated only by the angle.
_It represents a line segment M consisting of a parabola rotated by ₁ '. Due to this rotation, the vertex P ₃ of the parabola M becomes the point P ₃ ′.
Go to A point P ₃ ″ shown is a point where a line segment M ′ after rotation (shown by a broken line and formed of a parabola) intersects the axis Z. In FIG. 9 (B), it is formed by a rotated parabola. The line segment M ′ is located above the Z axis (that is, the part above the point P ₃ ″ is considered, and as shown in FIG. φ
As described above, the line segment M ″ describes a plane of rotation. Assuming that the axis Z ′ is also rotated together with the above-described rotation, the axis Z ′ is Z ′, Draw a cone as represented by Z ". However, this FIG. 9C is a schematic view so that it is easy to infer a three-dimensional shape, and is not an accurate plan view. (If you draw correctly, the bottom of the rotating body will be a straight line, not a vertically elongated ellipse like this figure). Figure 9
As can be easily understood from the fact that the drawing process described above with respect to FIG. 9A starts from the parabola in FIG. 9A, the light flux that has passed through the second focal point in FIG. When it reaches L'and is re-reflected by the rotating body, it becomes a re-reflected light flux parallel to the line Z'-Z '. Similarly, "when it is re-reflected by the line Z" point L of the virtual becomes re-reflected light beam parallel to the -Z ". That is, the crossing angle with respect to the axis Z corners theta ₁ '
And this angle θ ₁ ′ is set smaller than the critical angle. As a result, the re-reflected light flux is transmitted to the light guide 22a,
The light is incident on the light-receiving surface 22b (see FIG. 8) at an incident angle smaller than the critical angle and is effectively used. In the embodiment of FIG. 8, the two spheroidal reflectors 21a and 2ab are provided so that the first focus P ₁ is shared, but the number of these spheroidal reflectors 21a and 2ab can be set to an integer N of 3 or more. Accordingly, the number of installed light guides and auxiliary reflectors is also N.

FIG. 10 is an enlarged view schematically showing the vicinity of the light receiving portion of the light guide described in the embodiment shown in FIG. 8 above and schematically drawn, showing the critical angle of the optical fiber and the incident angle from the auxiliary reflector. It is the figure which compared and was filled in. The optical fiber 24 forming the light guide 22a has a critical angle θ ₂ as a characteristic value, and a light beam incident obliquely beyond this angle range is not effectively guided by the optical fiber 24. On the other hand, the re-reflected light from the auxiliary reflector has an incident angle θ.
_{At 1} , the light receiving surface of the light guide 22a is reached. here,
According to the equation (1), the incident angle θ ₁ is smaller than half the sea angle. Therefore, the re-reflected light enters the light guide 22a and is effectively guided.

[0009]

According to the spectral structure (FIGS. 8 to 10) provided with the auxiliary reflector according to the invention of the prior application, as described with reference to FIG. 10, the light guide 2 is used.
Since the incident angle θ ₁ of the reflected light from the auxiliary reflector with respect to the end face (light receiving face) of the optical fiber 24 forming 2a is within 1/2 of the critical angle θ ₂ of the optical fiber, the effective use of the luminous flux The effect of high rate was obtained. However, since it has the incident angle θ ₁ , the reflection loss at the end face is large as compared with the case where the incident angle is 0. Furthermore, FIG.
As can be seen from FIG. 3, the light receiving ends of the light guides 22a and 22b are exposed in the closed space surrounded by the spheroidal reflectors 21a and 21b, and the light source 5 arranged in the closed space generates heat. Therefore, there is also a problem that the light receiving end of the light guide is overheated. The present invention has been made in view of the above circumstances, and improves the light distribution structure according to the invention of the above-mentioned prior application. (A) The incident angle of reflected light with respect to the light receiving end of the light guide is zero. It is an object of the present invention to provide a light distribution structure in which the reflection loss at the end face is reduced to the minimum limit, and (b) there is no risk of the light receiving end of the light guide overheating.

[0010]

In order to achieve the above-mentioned object (reduction loss reduction / overheat prevention), a parallel incidence type light distribution structure according to the present invention has two focal points and is similar to a spheroid. A reflector having a concave reflection surface formed of a rotating surface,
A light source located at one of the two focal points and a light source located on a straight line connecting the two focal points, occupying a space including the other focal point position of the two focal points Is
An optical rod made of a transparent body, wherein a light beam emitted from a light source located at one of the focal points is reflected by the concave reflection surface toward the other focal point, and the optical rod is provided from a side surface of the optical rod. Light is incident on the inside of the optical rod and is focused on the other focal point in the optical rod, and the optical rod has a shape inserted into the reflector, and the optical rod is inserted. The tip portion is formed into a paraboloid of revolution that shares the other focal position as a focal point, and a light reflecting film is formed on the part of the paraboloid of revolution.

[0011]

According to the above construction, the light beam emitted from the light source located at one of the two focal points is reflected by the reflector, enters from the side surface of the optical rod, and is condensed at the other focal point. A light flux that intersects with the other focal point, is reflected by the paraboloid of revolution of the tip (specifically, is reflected by a reflective film formed on the paraboloid of revolution), and is parallel to the central axis of the optical rod. Will be reflected. As a result, when the light guide is concentrically connected to the optical rod, the parallel light flux is incident on the light receiving surface of the light guide at an incident angle of 0 (that is, perpendicular to the end surface on the light receiving side). ) Incident and the reflection loss at the end face is reduced to the theoretically possible minimum. Furthermore, since the light guide is sealed by the reflector and does not project into the space where the light source that is the heat source is arranged, the light rod receives light and guides it to the light guide. It is thermally isolated and there is no risk of overheating.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, referring to FIGS.
An embodiment of the present invention will be described. FIG. 1 is a sectional view schematically showing one embodiment of a parallel incidence type light distribution structure according to the present invention, and FIG. 8 showing a light distribution structure provided with an auxiliary reflector according to the invention of the prior application. It is a corresponding figure. The present embodiment (FIG. 1) is compared with the invention of the prior application (FIG. 8), and the different points, that is, the points improved by applying the present invention will be briefly described. 2) in which the tip of the light guide 22a is exposed inside the spheroidal reflector 21a, the light guide 2 of the present embodiment (FIG. 1) is
The tip of 2c is connected to an optical rod (for example, a glass rod) 32a, and the tip of the optical rod projects into the reflector 31a. Next, in contrast to the structure of the invention (FIG. 8) of the prior application in which the auxiliary reflector 23a re-reflects the light beam to guide it to the light guide 22a, in the present embodiment (FIG. 1), the optical rod 32a The reflection film 32a ₁ formed on the paraboloid of revolution 32a ₁ formed at the tip re-reflects the light beam and guides it to the light guide 22c via the optical rod 32a. The basic structural differences (improvements) are the above two, but there is another derivative improvement. That is, in the point that the light emitted from the light source located at the first focal point P ₁ is reflected by the reflector (21a or 31a) and condensed at the second focal point (P ₂ or P ₂ ′), the invention of the prior application (FIG. 8) and this embodiment (FIG. 1) are the same. However, in the invention of the prior application (FIG. 8), the optical path from the first focus P ₁ to the second focus P ₂ passes through the air,
In contrast to the straight optical path which is not refracted except for being reflected by the reflector, the optical rod 32 is used in the present embodiment (FIG. 1).
The optical path is refracted when it enters into a. As a result, the reflector 21a of the invention of the prior application (FIG. 8) was formed by the spheroidal surface, but the reflector 31a in the present embodiment (FIG. 1) corrects the above refraction to make the point P ₂ shown. ′ Is configured to collect the reflected light. In order to perform the above correction by design, consider a cross section along a plane including the Z-Z axis as in FIG. On the other hand, the light guide 22c is made of a material that has a required heat resistance and is transparent to visible light (optical glass is used in this embodiment). Since the refractive index can be known if the material of the light guide is determined, the spheroidal surface in the prior invention is slightly modified so that the reflected light is focused at the second focus P ₂ . If the spheroidal surface is treated as an ellipse by design for the plane figure as shown in FIG. 1, it is not difficult in terms of optical design technology to correct the ellipse and collect the reflected light at the second focal point. In this case, it is possible to use a computer, and further, the light focusing on the second focus P ₂ does not need to be focused strictly on one point (a point having no size) theoretically, and it is approximate. It is practically sufficient to focus the light on one point, so the above modification can be made by design technology. If the ellipse can be corrected in a plane, the pseudo spheroidal reflector 31a can be obtained by design by rotating the ellipse so that the curved surface becomes symmetrical with respect to the Z-Z axis. Here, the pseudo spheroid is a similar shape obtained by modifying the spheroid. FIG. 2 is a detailed schematic sectional view in which the vicinity of the optical rod shown in FIG. Light rod 3
2a is a glass rod optically connected to the light guide 22c, and the opposite side of the end connected to the light guide is concentric with the symmetry axis ZZ of the pseudo spheroidal reflector 31a. It projects into the pseudo-spheroidal reflector, and its tip is shaped into a paraboloid of revolution 32a ₁ . The above-mentioned paraboloid of rotation 32a ₁ is the above-mentioned axis ZZ
As the axis of symmetry, and the spheroidal reflector 31
The focus position is shared with the second focus P ₂ ′ of a. Therefore, the second focal point P ₂ ′ is located inside the optical rod 32a.

Light emitted from the light source 5 located at the first focal point P ₁ at a large diffusion angle θ ₅ as shown by a dotted arrow m and reflected by the pseudo spheroidal reflector 31a is shown by a dotted arrow m '. On the way to the second focal point P ₂ ′
It is blocked by a ₂ . Therefore, as indicated by the arrow q, the fact that the diffusion angle is within θ ₆ is the second angle when the light enters the optical rod 32a.
It is one of the conditions to reach the focus. Further, the light emitted with a small diffusion angle as indicated by the broken line arrow n is emitted by the optical rod 3
The light is incident on 2a obliquely and exceeds the critical angle, so that the surface is reflected as shown by an arrow n '. Therefore, another condition is that the diffusion angle is not more than θ ₇ as shown by the arrow u. FIG. 3 is shown to explain the relationship between the reflected light incident on the optical rod and the critical angle in the above-mentioned embodiment, and a diagram in which an optical path arrow is entered and an angle symbol is added to the schematic cross-sectional view of the main part. Is. y'is the optical rod 32a
Perpendicular to the axis Z-Z described above. The angle θ ₉ shown in FIG. 3 is a critical angle of the optical rod 32a. Although the critical angle has been described above with reference to FIG. 10 described above, the critical angle θ ₂ shown in FIG.
It is a critical angle of 4. The critical angle is an optical characteristic value that differs depending on the material. The critical angle θ ₅ shown in FIG.
It is the critical angle of 2a. Optical path arrows q, u, shown in FIG.
n and n ′ are optical path arrows q, u, and
It corresponds to n and n '.

[0014]

When the present invention is applied, the luminous flux emitted from the light source located at one of the two focal points is reflected by the reflector, enters from the side surface of the optical rod, and is condensed at the other focal point. , Crosses at the other focal point, is reflected by the paraboloid of revolution of the tip (specifically, is reflected by a reflective film formed on the paraboloid of revolution), and is parallel to the central axis of the optical rod. It is reflected so that it becomes a light flux. As a result, when the light guide is concentrically connected to the optical rod, the parallel light flux is incident on the light receiving surface of the light guide at an incident angle of 0 (that is, perpendicular to the end surface on the light receiving side). ) Incident and the reflection loss at the end face is reduced to the theoretically possible minimum. Furthermore, since the light guide is sealed by the reflector and does not project into the space where the light source that is the heat source is arranged, the light rod receives light and guides it to the light guide. It has an excellent practical effect that it is thermally isolated and there is no risk of overheating.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of a parallel incidence type light distribution structure according to the present invention, and FIG. 8 illustrates a light distribution structure including an auxiliary reflector according to the invention of the prior application. It is a figure corresponding to.

FIG. 2 is a detailed schematic cross-sectional view in which the vicinity of the optical rod shown in FIG. 1 above is drawn in an enlarged manner.

FIG. 3 is shown for explaining the relationship between the reflected light incident on the optical rod and the critical angle in the above-mentioned embodiment, and an optical path arrow is entered and an angle symbol is added to the schematic cross-sectional view of the main part. It is a figure.

FIG. 4 is a perspective view showing a known example of a light distribution structure.

FIG. 5 is a schematic side view showing a known example different from the above.

6A and 6B show a tentative plan relating to a light distribution device, FIG. 6A is a schematic side view, and FIG. 6B is a BB cross-sectional view thereof.

FIG. 7 is an external perspective view schematically showing an embodiment of a light distribution structure according to the invention of the prior application.

FIG. 8 is a view showing a light distribution structure provided with an auxiliary reflector according to the invention of the prior application, in which an optical path arrow is added to a sectional view schematically illustrating a main part.

9 is a diagram showing a design procedure for obtaining the three-dimensional shape of the auxiliary reflector in FIG. 8 described above, which is (A).
Is a target curve for the Z axis, and (B) is a method for obtaining the line segment M ′ by coordinate conversion into a form in which the Z axis is rotated.
(C) represents a method of rotating the line segment M ′ around the axis Z to obtain a rotation surface forming a reflection surface.

FIG. 10 is an enlarged view schematically showing the vicinity of the light receiving portion of the light guide described in the embodiment shown in FIG. 8 described above in an enlarged view and showing the critical angle of the optical fiber and the incident angle from the auxiliary reflector. It is the figure filled in contrastingly.

[Explanation of symbols]

1 ... Special tube, 2 ... Optical fiber, 3 ... Lamp, 4 ... Rotating parabolic mirror, 5 ... Light source, 6 ... Optical fiber, 7 ... Glass rod, 8, 8A, 8B ... Spheroidal mirror, 9 ... Convex lens,
9a to 9e ... Light guide, 10 ... Socket, 11 ... Harness, 21a, 21b ... Spherical surface reflector, 22
a, 22b, 22c ... Light guide, 23a, 23b ...
Secondary reflector, 31a, 31b ... pseudo spheroidal reflector, 32a ... light rod, 32a ₁ ... paraboloid,
32a ₂ ... Reflective film.

Claims (1)

[Claims] 1. A reflector having two focal points and having a concave reflecting surface consisting of a surface of revolution similar to a spheroid, and a light source positioned at one of the two focal points, An optical rod made of a transparent body, the optical rod being arranged on a straight line connecting the two focal points and occupying a space including the other focal point position of the two focal points; The light beam emitted from the light source located at the focal point is reflected by the concave reflecting surface toward the other focal point, enters the optical rod from the side surface of the optical rod, and is incident on the other focal point in the optical rod. It is designed to collect light,
Further, the optical rod has a shape inserted into the reflector, and the tip end portion into which the optical rod is inserted is formed into a paraboloid of revolution sharing the other focal point as a focal point. A parallel incidence type light distribution structure, wherein a light reflection film is formed on the rotation paraboloid portion.