JP2004235127A - Floodlight device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact floodlight device which makes visual field good when it is cut off by rain or fog. <P>SOLUTION: A first and a second polarizing beam splitters 13 and 14, respectively, divide unpolarized light L into p-polarized light P and s-polarized light S1, transmit the p-polarized light P and the unpolarized light L in the same direction, and reflect the s-polarized light S1. A first and a second reflecting mirrors 7 and 8 reflect the s-polarized light in the same direction as the p-polarized light. The floodlight device 1 irradiates either one of the s-polarized or the p-polarized light divided by the first and the second polarizing beam splitter 13 and 14 as a first vertically polarized light having a plane of vibration of electric field approximately vertical to the ground, while also irradiating the other one of the p-polarized or the s-polarized light as a second vertically polarized light converted with a first and a second half-wave plates 5 and 6 into light having a plane of vibration of electric field approximately vertical to the ground. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light emitting device such as a headlight and a fog lamp mounted on a vehicle.
[0002]
[Prior art]
The headlights and fog lamps mounted on the vehicle are turned on when it is difficult for the naked eye to see the situation in front. For example, the headlight is used at night when the surroundings are dark, in a tunnel, at the time of heavy rain or fog when visibility ahead is poor.
[0003]
However, if the vehicle's headlights are turned on when heavy fog is obstructed or heavy rainfall blocks the front of the vehicle, the emitted light is diffusely reflected by raindrops and fog particles, and it is as if a light wall is in front of the vehicle. May appear and obstruct the view ahead.
[0004]
FIGS. 14A and 14B are diagrams showing the state of light emitted from the headlight during heavy fog and heavy rain, where FIG. 14A is a schematic diagram showing the state of light distribution of the headlight at that time, and FIG. It is a schematic diagram which shows the situation of the irregular reflection produced on the surface of a raindrop.
[0005]
As shown in FIG. 14A, light emitted from a headlight is irregularly reflected on the surface of fine particles of water vapor and raindrops present on an optical path, and forms a light wall near a vehicle. However, the driver cannot secure a distant view.
[0006]
As shown in FIG. 14B, the light is reflected many times in various directions on the surface of the raindrop, and a light wall caused by the raindrop illuminated by the headlight appears in front of the vehicle. Can be In such a situation, it is not possible to confirm an object that can be confirmed in the case of normal visibility.
[0007]
Here, raindrops that fly from the air during heavy fog and heavy rain have a substantially spherical shape. However, as the grain size increases, the raindrops become flat due to the air resistance at the time of falling and the surface area increases. Since the raindrop has such a shape, the light of the headlight that enters from the side is irregularly reflected in various directions, and is particularly diffused and reflected in a direction perpendicular to the ground. Furthermore, during heavy fog and heavy rain, since the number density of raindrops per unit volume is high, the light once irregularly reflected by raindrops is repeatedly reflected by many nearby raindrops. Raindrops illuminate the entire area illuminated by the light illuminated from above, making it seem as if a light wall appeared near the vehicle, obstructing the field of view and making it difficult to see far away.
[0008]
Meanwhile, there is an invention that blocks light of a headlight in which a polarizer is incorporated in a headlight of a vehicle (for example, see Patent Document 1). The present invention prevents a driver from being dazzled by a headlight in a high beam state.By incorporating a polarizer in a high beam headlight and an analyzer in a windshield, the driver can control an oncoming vehicle. This is to prevent dazzling by the high beam.
[0009]
[Patent Document 1]
JP-A-61-253236 (page 2, FIGS. 1 to 3)
[0010]
[Problems to be solved by the invention]
However, the invention described in Patent Literature 1 uses a polarizer (polarizing filter) to cut off light emitted from a headlight, so that light is lost by 50% or more. There is a problem that the usage rate is poor and the image becomes dark.
For this reason, when the headlight is used during heavy fog or heavy rain, the front of the irradiation becomes even darker.
That is, since the headlight of Patent Document 1 cannot illuminate the front brightly and does not correspond to the case where the field of view is blocked by heavy fog or heavy rain, it has an effect of improving the field of view at that time. Not.
[0011]
In addition, since a polarizer (polarizing filter) generally has a low heat-resistant temperature, when it is mounted on a headlight or the like, there is a problem that the polarization performance is rapidly deteriorated due to the heat of the headlight lamp. is there.
[0012]
Furthermore, when the floodlight is used as a vehicle headlight, there are restrictions when installing it, due to the shape of the installation part of the vehicle where the headlight is installed and the structure of the floodlight, and also in terms of design. It was to receive.
[0013]
An object of the present invention is to provide a light projecting device that has high light use efficiency, is compact, and is not subject to design restrictions so that the view can be improved when the view is blocked by rain or fog. It is in.
[0014]
[Means for Solving the Problems]
In order to solve the problem, the light projecting device according to claim 1 includes a light source that emits unpolarized light, a parabolic mirror that converts unpolarized light emitted from the light source into a parallel light beam, and a light source that emits unpolarized light. It is arranged in the periphery and separates unpolarized light from the parabolic mirror into p-polarized light and s-polarized light, transmits p-polarized light in the same direction as the direction of incidence of the unpolarized light, and reflects s-polarized light. The s-polarized light is reflected by the first and second polarization separation means in the same direction as the p-polarization light, while being installed on the outer periphery of the first and second polarization separation means. Reflecting means for reflecting, and either one of the s-polarized light or the p-polarized light separated by the first and second polarized light separating means as a first vertically polarized light having a vibration plane of an electric field substantially perpendicular to the ground. Irradiate and convert the other side of p-polarized light or s-polarized light to the vibration plane of the electric field And irradiating by converting the second vertical polarized light having a substantially vertical electric field oscillation plane relative to the ground by that converter.
[0015]
According to the first aspect of the present invention, the polarized light separating means is divided and disposed around the light source, and the s polarized light reflected by each polarized light separating means is reflected by the p polarized light transmitted through each polarized light separating means. Thus, the irradiation direction can be adjusted, and both the p-polarized light and the s-polarized light can be irradiated in the front as vertical polarized light. This converts all unpolarized light emitted from the light source into vertically polarized light, effectively utilizing light, suppressing vertical reflection, illuminating the front clearly, and securing the front view. Can be. Further, by arranging the polarization splitting means separately around the light source, the light projecting device can be made compact.
[0016]
The light projecting device according to claim 2 is the light projecting device according to claim 1, wherein the polarization splitting unit is disposed so as to be divided in a substantially horizontal direction, and a non-polarized light incident surface radiated from the light source is disposed. It has first and second polarized light separating means extending horizontally, and the p-polarized light separated by the first and second polarized light separating means is transmitted by the converting means after being transmitted in the same direction as non-polarized light. The s-polarized light converted into the second vertically polarized light and separated by the first and second polarized light separating means is reflected in a substantially horizontal direction and then irradiated by the reflecting means in the same direction as the p-polarized light. It is characterized by being irradiated as polarized light.
[0017]
According to the second aspect of the present invention, the first and second polarization splitting means are arranged so as to be divided in a substantially horizontal direction, and the incident surface is formed so as to extend substantially horizontally. The s-polarized light separated and reflected by the first and second polarized light separating means has a vibration plane of an electric field substantially perpendicular to the ground, and can be used as the first vertically polarized light in that state. Thereby, the oscillating plane in the vertical direction is converted by the conversion unit to the p-polarized light directly irradiated from the first and second polarization separation units, as compared with the s-polarized light irradiated through the reflection unit. The structure for providing the conversion means is simplified, and the size of the light projecting device can be further reduced.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a light projecting device according to the present invention will be described in detail with reference to the accompanying drawings. In the description of the present embodiment, “p-polarized light, s-polarized light, horizontal polarized light, and vertical polarized light” will be first described for convenience of description, and then “a first embodiment of a light projecting device according to the present invention”. ”And“ Second embodiment of the light projecting device according to the present invention ”.
In the embodiment of the present invention, “front” is the front side of the vehicle, “rear” is the rear side of the vehicle, “upper” is the vertical upper side, and “lower” is the vertical lower side.
[0019]
(P-polarized light, s-polarized light, horizontal polarized light, vertical polarized light)
First, p-polarized light, s-polarized light, horizontal polarized light, and vertical polarized light will be described with reference to FIGS.
FIG. 1 is a schematic perspective view for explaining p-polarized light and s-polarized light. FIGS. 2A and 2B are diagrams for explaining the difference between s-polarized light and p-polarized light and horizontal polarized light and vertical polarized light. FIG. 2A illustrates p-polarized light when the polarization separation means is installed parallel to the ground. FIG. 4B is a schematic perspective view showing the vibration direction of the s-polarized light, FIG. 4B is a schematic side view showing the vibration direction of the p-polarized light and the s-polarized light when the polarized light separating means is installed parallel to the ground, and FIG. Is a schematic perspective view showing vibration directions of p-polarized light and s-polarized light when the light is installed with respect to the ground, and FIG. It is a schematic side view which shows a direction.
[0020]
As shown in FIG. 1, p-polarized light is linearly polarized light whose electric field vibration direction (electric field vector) is parallel to the plane of incidence, and s-polarized light is that the vibration direction of the electric field is perpendicular to the plane of incidence. It is linearly polarized light. Note that the term “incident surface” refers to a surface that includes a normal to a reflecting surface from which light is reflected and an optical axis of the incident light. That is, the p-polarized light and the s-polarized light are concepts defined for the incident plane.
[0021]
On the other hand, horizontal polarization and vertical polarization are concepts defined with respect to the ground, and polarization in which the electric field oscillates parallel to the ground is called horizontal polarization, and the oscillating direction of the electric field is perpendicular to the ground. Polarized light is called vertical polarized light. Therefore, as shown in FIGS. 2 (a) and 2 (b), when the incident surface of the polarized light separating means is arranged perpendicular to the ground, that is, when the ground is a reflecting surface, the polarized light separating means is used. The separated p-polarized light matches the vertical polarization and the s-polarized light matches the horizontal polarization.
Further, as shown in FIGS. 2C and 2D, when the incident surface of the polarization splitting means is not arranged perpendicular to the ground, that is, when the ground is not a reflecting surface, p-polarized light, s The polarized light does not coincide with the vertically polarized light and the horizontally polarized light, respectively.
[0022]
(First Embodiment)
Next, a light projecting device according to a first embodiment of the present invention will be described with reference to FIGS.
[0023]
FIG. 3 is a perspective view schematically showing the configuration of the light emitting device according to the first embodiment of the present invention. FIG. 4 is a front view of the light emitting device shown in FIG. FIG. 5 is a sectional view taken along line AA in FIG.
[0024]
The light projecting device 1 shown in FIG. 3 separates non-polarized light L emitted from the light source 2 into p-polarized light P and s-polarized light S by first and second polarizing beam splitters 13 and 14, and s-polarized light among these. S is the first vertically polarized light, and the p-polarized light P further separated is converted into the second vertically polarized light by the first and second half-wave plates 5 and 6, and the first and second polarized lights are converted to the second vertically polarized light. This device irradiates vertically polarized light.
[0025]
The light projecting device 1 includes a light source 2 that emits unpolarized light L, a parabolic mirror 9 for aligning the unpolarized light L emitted from the light source 2 in a forward direction to be a parallel light beam, and a periphery of the light source 2. And splits the non-polarized light L from the parabolic mirror 9 into p-polarized light P (horizontal polarized light) and s-polarized light S, and converts the p-polarized light P (horizontal polarized light) to the unpolarized light L. The first and second polarization beam splitters 13 and 14 that transmit in the same direction and reflect the s-polarized light S are installed on the outer periphery of the first and second polarization beam splitters 13 and 14, and A first reflecting surface that reflects either the s-polarized light S or the p-polarized light P separated by the first and second polarizing beam splitters 13 and 14 and has a vibration plane of an electric field substantially perpendicular to the ground; First and second reflections for illumination as vertically polarized light A first and a second half-wave plate for converting the other one of the p-polarized light P and the s-polarized light S into a second vertically polarized light having a vibration plane of an electric field substantially perpendicular to the ground; 5 and 6.
[0026]
The "first and second polarization beam splitters 13 and 14" correspond to the "first and second polarization separation means" in the claims. The “first and second half-wave plates 5 and 6” correspond to “polarization conversion means” in the claims, and the “first and second reflecting mirrors 7 and 8” correspond to the patents. It corresponds to "first and second reflection means" in the claims.
[0027]
Hereinafter, details of each unit of the light emitting device 1 will be described with reference to FIGS. 3 to 5.
The light projecting device 1 suppresses the diffuse reflection of light emitted from the headlight due to water vapor fine particles and raindrops, which is mainly diffused in the vertical direction and obstructs the field of view, thereby irradiating the front clearly and increasing the field of view. It is a device to secure.
[0028]
As shown in FIGS. 3 and 5, the light source 2 is composed of a lamp that emits unpolarized light L such as, for example, an HID (High Intensity Discharge) light, and is installed on the central optical axis O of the light projecting device 1. . The light source 2 has a proximal end 2a connected to a terminal portion 11 installed at a rear portion of a lamp housing (not shown), and a distal end portion 2b inserted through a through hole 12a of a shade 12 and arranged in a cylindrical portion 12b. are doing.
[0029]
As shown in FIG. 5, the light emitting point 2c of the light source 2 is disposed at the center between the parabolic mirror 9 and the spherical mirror 10. The light source 2 is a lamp that emits unpolarized natural light L around the light emitting point 2c. Most of the unpolarized light L emitted from the light source 2 irradiates the spherical mirror 10 and the parabolic mirror 9. The light source 2 is turned on by turning on a lighting switch (not shown) of a combination switch (not shown) installed near the driver's seat.
[0030]
The light source 2 is not limited to the HID light, but may be another lamp such as a halogen headlamp or a xenon headlamp, and the type thereof is not particularly limited.
[0031]
The shade 12 is formed of, for example, a substantially cylindrical member in which the through hole 12a, the cylindrical portion 12b, and the spherical mirror 10 are integrally formed of glass or the like, and is installed on the optical axis O. The through hole 12a is a hole through which the distal end portion 2b of the light source 2 is inserted. A lamp cover 12c or a lens (not shown) made of, for example, a transparent material such as glass is provided on the front surface of the cylindrical portion 12b.
[0032]
The spherical mirror 10 is provided to increase the efficiency of using light from the light source 2, and is, for example, a concave mirror having a spherical surface having a light emitting point 2 c of the light source 2 as a center and a parabolic mirror of the shade 12. It is installed on the 9 side. The spherical mirror 10 is a mirror for reflecting the non-polarized light L emitted from the light source 2 to the parabolic mirror 9. The unpolarized light L reflected by the spherical mirror 10 is further reflected by the parabolic mirror 9 to be a parallel light beam parallel to the optical axis O.
[0033]
The parabolic mirror 9 is a mirror installed around the light emitting point 2c of the light source 2 so as to cover the light emitting point 2c. The parabolic mirror 9 is, for example, an aspherical mirror formed by vapor-depositing aluminum or the like that reflects spherical light radiated in all directions from the light emitting point 2c of the light source 2 to plane light, and having a substantially bowl shape. In front of the parabolic mirror 9, semi-cylindrical first and second polarizing beam splitters 13 and 14 which are cylindrically matched are provided separately. The parabolic mirror 9 includes a first and a second polarizing beam splitter in which the unpolarized light L directly radiated from the light emitting point 2c of the light source 2 and the unpolarized light L reflected by the spherical mirror 10 are disposed on the left and right front sides. These mirrors reflect toward 13 and 14 and convert them into parallel rays parallel to the optical axis O.
[0034]
The first and second polarization beam splitters 13 and 14 are formed by coating first and second thin film laminates 3 and 4 on the slopes of two semi-cylindrical half prisms that become cylindrical when they match with each other by coating or the like. Become. The first and second polarization beam splitters 13 and 14 refract the incident non-polarized light L so that the incident angle becomes the Brewster angle by the refractive index of the prism, and the first and second polarization beam splitters 13 and 14 respectively. When light is incident on the first and second thin film stacks 3 and 4 in 14 at a Brewster angle, the light transmits p-polarized light P and reflects s-polarized light S. The first and second polarization beam splitters 13 and 14 convert the non-polarized light L reflected forward by the parabolic mirror 9 into p-polarized light P whose vibration direction of the electric field is parallel to the plane of incidence and the incidence of the electric field. This is a polarization splitting element that splits light into s-polarized light S perpendicular to the plane.
The first and second polarization beam splitters 13 and 14 are installed on the left and right sides of the outer periphery of the cylindrical portion 12b of the shade 12, and are installed on the front surfaces thereof in the horizontal direction on the left and right sides with respect to the optical axis O. First and second half-wave plates 5 and 6 at 90 degrees with respect to the axis O are provided.
[0035]
The first and second thin film stacks 3 and 4 installed on the first and second polarization beam splitters 13 and 14 are provided with the outer peripheral surfaces of the first and second polarization beam splitters 13 and 14 and the shade 12. It is divided in the horizontal direction on the left and right between the cylindrical portion 12b, and is installed obliquely with respect to the optical axis O so as to reflect the unpolarized light L outward.
[0036]
FIG. 6 is a diagram showing the light projecting device according to the first embodiment of the present invention, and is a schematic diagram showing the structure of the first thin film stack 3 installed on the first polarizing beam splitter.
Since the second thin film stack 4 is the same as the first thin film stack 3 symmetrically installed, one of the first thin film stacks 3 will be described in detail with reference to FIG.
[0037]
The first thin film stack 3 inside the first polarizing beam splitter 13 includes, for example, a high refractive index film 3a made of a plurality of transparent resins or glass and a low refractive index film 3b made of a gas layer such as air. When the non-polarized light L enters the first thin film laminate 3, the light is separated into p-polarized light P and s-polarized light S, transmits the p-polarized light P, and converts the s-polarized light S into the first light. And the second reflecting mirrors 7 and 8 are reflected in a certain horizontal direction.
[0038]
Here, as shown in FIG. 5, the p-polarized light P is not reflected by the first and second polarization beam splitters 13 and 14, but passes through the first and second polarization beam splitters 13 and 14, and The light enters the first and second half-wave plates 5 and 6.
The s-polarized light S is reflected by the first and second polarization beam splitters 13 and 14 and changes its traveling direction. The first and second polarization beam splitters 13 and 14 are disposed on the outer periphery of the first and second polarization beam splitters 13 and 14. The second reflecting mirrors 7 and 8 are irradiated.
[0039]
In the first embodiment, first and second polarization beam splitters 13 and 14, which are first polarization splitting means, are installed in the horizontal direction on the left and right sides with respect to the optical axis O, and the light emitted from the light source 2 is emitted. Since the plane of incidence of the polarized light L is formed in the horizontal direction, the relationship of p-polarized light P = horizontal polarized light and s-polarized light S = vertical polarized light holds.
[0040]
As shown in FIG. 5, the first and second reflecting mirrors 7 and 8 are installed substantially parallel to the outer peripheral portions of the first and second thin film stacks 3 and 4, and the direction of the s-polarized light S is p-polarized. It is composed of two left and right plane mirrors installed at a predetermined angle to the front with respect to the optical axis O so as to irradiate the front of the vehicle in the same direction as P. The first and second reflecting mirrors 7 and 8 are installed around semi-cylindrical first and second polarizing beam splitters 13 and 14, and have a substantially crescent shape (see FIG. 4). The first and second reflecting mirrors 7 and 8 reflect the s-polarized light S reflected in the outer peripheral direction by the first and second thin film stacks 3 and 4 in the same direction as the p-polarized light P, and The light passes through the outer peripheral portions of the first and second half-wave plates 5 and 6 and irradiates the front of the vehicle as first vertically polarized light.
[0041]
The first and second half-wave plates 5 and 6 are formed, for example, in a plate shape formed by stacking two quarter-wave plates made of transparent resin for liquid crystal. The first and second half-wave plates 5 and 6 make use of the interference linear effect due to the difference in the refractive index between the horizontally polarized light and the vertically polarized light. It has a function of converting the vibration direction of the polarized light P (incident light) by 90 degrees. The first and second half-wave plates 5, 6 are installed in front of the first and second polarization beam splitters 13, 14, respectively, and the first and second polarization beam splitters 13, 14 are provided. This is conversion means for converting the passed p-polarized light P so as to have a vibration plane of an electric field perpendicular to the ground. Polarized light emitted from the first and second half-wave plates 5, 6 illuminates the front of the vehicle as second vertically polarized light.
As shown in FIG. 4, the first and second half-wave plates 5 and 6 have a substantially symmetrical semi-circular shape disposed around the front end of the shade 12.
[0042]
The first and second half-wave plates 5 and 6 are installed so as to be directly attached to the front surfaces of the first and second polarizing beam splitters 13 and 14 which are cylindrically matched. The first and second polarization beam splitters 13 and 14 may be installed separately from the front surface.
In addition, a lamp cover or a lens made of a transparent body may be appropriately installed on the front surface of the light emitting device 1.
[0043]
According to the light projecting device of the first embodiment configured as described above, the operation is performed as follows.
When a lighting switch (not shown) is turned on, the light source 2 (see FIG. 5) is turned on.
As shown in FIG. 5, most of the unpolarized light L emitted from the light source 2 is reflected by the spherical mirror 10 and irradiates the parabolic mirror 9 or directly irradiates the parabolic mirror 9 and A part of the unpolarized light L coming out of the front end portion 2b is transmitted to the lamp cover 12c to irradiate the front. The non-polarized light L irradiated on the parabolic mirror 9 is reflected in a forward direction parallel to the optical axis O, and irradiates the first and second polarizing beam splitters 13 and 14.
[0044]
The non-polarized light L enters the first and second polarization beam splitters 13 and 14 and is refracted so that the incident angle becomes the Brewster angle by the refractive index of the prism. When light enters the first and second thin film stacks 3 and 4 in the first and second polarizing beam splitters 13 and 14 at a Brewster angle, the light is separated into p-polarized light P and s-polarized light S. Is done. The s-polarized light S is reflected and irradiates the first and second reflecting mirrors 7 and 8, and the p-polarized light P is transmitted and irradiates the first and second half-wave plates 5 and 6. The s-polarized light S is reflected by the first and second reflecting mirrors 7 and 8 in the same direction as the p-polarized light P, and illuminates the front as first vertically polarized light.
[0045]
Further, the p-polarized light P separated by the first and second polarizing beam splitters 13 and 14 is converted into a second vertical polarized light by first and second half-wave plates 5 and 6, and is grounded. In the vertical direction, a vertically polarized light having a small reflectance is irradiated forward.
[0046]
Since the light projecting device 1 irradiates the front with the first and second vertically polarized light, the reflectance of the first and second vertically polarized light in the direction perpendicular to the ground is smaller than that of the horizontally polarized light. The degree of reflection diffused in the vertical direction can be significantly reduced as compared with the case of irradiating the polarized light L. For example, even in heavy fog and heavy rain, it is possible to suppress the vertically diffuse reflection of water vapor particles and raindrops, suppress the vertically diffused reflected light, suppress the light wall, and reduce the visibility. A distant field of view can be ensured without being blocked.
[0047]
FIG. 7 is a diagram illustrating an example in which the light projecting device 1 is applied to a headlight of a vehicle, and FIG. 7A is a schematic diagram illustrating a distribution state of light emitted from the light projecting device during heavy fog and heavy rain. And (b) is a schematic diagram showing a state of diffuse reflection occurring on the surface of a raindrop when light is emitted from a light projecting device.
[0048]
As shown in FIG. 7A, the light projecting device 1 is, for example, a headlight of a vehicle, and is installed at the left and right front ends of the vehicle body. The vertically polarized light emitted from the light projecting device 1 is compared with a conventional headlight that irradiates unpolarized light even when it is incident on water vapor fine particles or raindrops when the view is blocked by dense fog or heavy rain. The proportion of light that is diffused and reflected in the vertical direction is significantly reduced. For this reason, the driver can secure a field of view in front of the vehicle without seeing a light wall in front of the vehicle, and can visually recognize the driver from a distance.
[0049]
Further, as shown in FIG. 7 (b), when the light projecting device 1 irradiates the vertically polarized light, the vertically diffused reflection generated on the surface of the raindrop is suppressed to be small. It is possible to secure a forward view without being obstructed by the vehicle.
[0050]
In addition, when driving a vehicle during the nighttime of rainy weather, the irradiation of another vehicle reflected by a water film present on the road surface enters the field of view, so that the road surface appears to be glaring and it may be very difficult to travel.
[0051]
However, the light emitting device according to the first embodiment of the present invention allows the driver of the oncoming vehicle to receive light from the light emitting device 1 by suppressing the reflection of the irradiation on the road surface even during nighttime in rainy weather. It is possible to reduce glare of the light that has been irradiated and reflected on the road surface. For this reason, it becomes possible to improve the visibility ahead of the driver of the own vehicle and the driver of the oncoming vehicle, and to drive the vehicle more comfortably.
[0052]
Further, the light projecting device according to the first embodiment of the present invention converts the p-polarized light P separated by the first and second polarization splitters 13 and 14 into the first and second half-wave plates 5. , 6 convert the light into the second vertically polarized light and irradiate the light, so that the light emitted from the light source 2 can be efficiently emitted forward without blocking. For this reason, it is possible to eliminate obstruction of the field of view in front of the vehicle, and to irradiate brightly and clearly. In addition, the light projecting device 1 can be designed to be optimally designed for a headlight by making the whole thereof substantially circular.
[0053]
(Second embodiment)
Next, a light emitting device according to a second embodiment of the present invention will be described with reference to FIGS.
In the description of the second embodiment, the same components as those of the first embodiment will be denoted by the same reference numerals, and duplicate description will be omitted.
FIG. 8 is a schematic front view showing a light projecting device according to the second embodiment of the present invention. FIG. 9 is a schematic perspective view showing a light emitting device according to the second embodiment of the present invention. FIG. 10 is a schematic perspective view showing a light emitting device according to the second embodiment of the present invention.
As shown in FIGS. 8 to 10, a light projecting device 15 of the second embodiment is obtained by changing the substantially circular light projecting device 1 of the first embodiment to a square shape.
[0054]
FIG. 11 is a schematic cross-sectional view showing the second embodiment of the present invention, and is a cross-sectional view as viewed from line BB in FIG.
As shown in FIG. 11, the light projecting device 15 includes a light source 2, a parabolic mirror 9 for aligning an irradiation angle of the non-polarized light L emitted from the light source 2 in a forward direction to be a parallel light beam, and a light source 2. And a non-polarized light L from the parabolic mirror 9 is converted into p-polarized light (horizontal polarized light) and s-polarized light (first vertical polarized light). First and second polarization beam splitters 22 and 23 for splitting into S, and reflect the s-polarized light (first vertical polarization) S separated by the first and second polarization beam splitters 22 and 23. And second reflecting mirrors 18 and 19 for converting the p-polarized light (horizontal polarized light) P passing through the first and second polarizing beam splitters 22 and 23 into a second vertical polarized light. It is composed of a plate 20 and a housing 21 (see FIGS. 8 to 10).
[0055]
The first and second polarizing beam splitters 21 and 22 are divided and arranged in a substantially horizontal direction, and are formed such that an incident surface of the non-polarized light L emitted from the light source 2 extends horizontally. The p-polarized light P separated by the first and second thin film stacks 16 and 17 provided in the first and second polarizing beam splitters 21 and 22 is １ ／ after being transmitted in the same direction as the unpolarized light L. The light is converted into the second vertically polarized light by the wave plate 20. The s-polarized light S separated by the first and second polarization beam splitters 21 and 22 is reflected in a substantially horizontal direction, and then irradiated by the first and second reflecting mirrors 18 and 19 in the same direction as the p-polarized light P. Irradiated as the first vertically polarized light.
[0056]
The “first polarization beam splitter 21” corresponds to “a first polarization splitting unit” in the claims. Further, the “second polarization beam splitter 22” corresponds to “second polarization splitting means”, the “１ ／ wavelength plate 20” corresponds to “conversion means”, and “first and second polarization beam splitters”. The “reflecting mirrors 18 and 19” correspond to “reflecting means”.
[0057]
Hereinafter, details of each unit of the light projecting device 15 will be described with reference to FIGS.
The light projecting device 15 shown in FIGS. 8 to 10 is, for example, a fog lamp of a vehicle, and is installed at the left and right front ends of a vehicle body (not shown). The light source 2 is turned on by turning on a combination switch (not shown) provided near the driver's seat or a fog lamp switch (not shown) provided on the instrument panel, and illuminates the front of the vehicle.
[0058]
As shown in FIG. 11, a shade 12 is provided at the center on the front surface of a parabolic mirror 9 that reflects the non-polarized light L of the light source 2 in parallel with the optical axis O. First and second polarization beam splitters 22 and 23 are disposed in the horizontal direction.
[0059]
The first and second polarizing beam splitters 22 and 23 are formed of prismatic prisms installed on the left and right of the outer peripheral portion of the cylindrical portion 12b of the shade 12, and the first and second thin film stacks 16 and 17 are provided by coating or the like.
[0060]
FIG. 12 is a diagram showing a light projecting device according to the second embodiment of the present invention, and is a schematic perspective view of a first polarizing beam splitter.
As shown in FIG. 12, the first prismatic beam splitter 22 having a rectangular tube shape has a semi-cylindrical cutout 22c for supporting the shade 12 from the right side, such as a glass or the like formed along the optical axis O. A first thin-film laminate 16 is provided inside the cylinder. The first polarizing beam splitter 22, as in the present embodiment, is formed by, for example, vertically stacking cylindrical joint portions 22a and 22b which are symmetrical with each other.
[0061]
FIG. 13 is a diagram showing a light projecting device according to the second embodiment of the present invention, and is a schematic perspective view of a second polarizing beam splitter.
As shown in FIG. 13, the second polarization beam splitter 23 is a rectangular cylinder made of glass or the like having a symmetric shape with respect to the first polarization beam splitter 22. The second polarizing beam splitter 23 has a semi-cylindrical cutout 23c for supporting the shade 12 from the left side along the optical axis O, and has a second thin film stack 17 provided therein. As in the present embodiment, the second polarization beam splitter 23 is formed by, for example, overlapping vertically symmetric joints 23a and 23b.
[0062]
The second polarization beam splitter 23 and the first polarization beam splitter 22 (see FIG. 12) are aligned so that the notch 22c (see FIG. 12) and the notch 23c form a cylindrical hole. The shade 12 is installed in the hole.
[0063]
A first polarizing beam splitter 22 in which two cylindrical joints 22a and 22b shown in FIG. 12 are vertically stacked, and a cylindrical joint 23a and a cylindrical joint 23b shown in FIG. The second polarizing beam splitter 23 in which are stacked may be formed as a single unit and installed so as not to overlap.
[0064]
The first and second polarization beam splitters 22 and 23 in the second embodiment are made of the same material as the first and second polarization beam splitters 13 and 14 (see FIG. 3) in the first embodiment. Is changed to a square prism and is vertically installed on the left and right.
[0065]
As shown in FIG. 11, the first and second thin film stacks 16 and 17 of the first and second polarization beam splitters 22 and 23 transmit the p-polarized light P and make the p-polarized light P enter the half-wave plate 20. , The s-polarized light S is reflected and the traveling direction is changed to irradiate the first and second reflecting mirrors 18 and 19.
[0066]
As shown in FIG. 8 and FIG. 9, the first and second reflecting mirrors 18 and 19 in the second embodiment are the same as the first and second reflecting mirrors 7 and 8 (FIG. 3) is made of the same material as that of Example 1, but is changed to a square. The first and second reflecting mirrors 18 and 19 are held by a housing 21 interposed therebetween.
[0067]
As shown in FIG. 11, the first and second reflecting mirrors 18 and 19 are provided with two right and left squares which are installed at a predetermined angle so that the s-polarized light S irradiates the same direction as the p-polarized light P. Consisting of a plane mirror. The first and second reflecting mirrors 18 and 19 reflect the s-polarized light S reflected in the outer peripheral direction by the first and second polarizing beam splitters 22 and 23, and After passing through the outer peripheral portion, the front side of the vehicle is irradiated as the first vertically polarized light.
[0068]
In the second embodiment, the first and second polarization beam splitters 22 and 23, which are the first polarization splitting means, are installed such that the plane of incidence of the non-polarized light L emitted from the light source 2 is horizontal. Therefore, the relationship of p-polarized light P = horizontal polarized light and s-polarized light S = vertical polarized light holds.
[0069]
The p-polarized light P incident on the half-wave plate 20 is converted into polarized light having a vibration plane of an electric field substantially perpendicular to the ground, and irradiates the front of the vehicle as second vertically polarized light.
[0070]
As shown in FIG. 9, the half-wave plate 20 in the second embodiment is the same as the first and second half-wave plates 5 and 6 (see FIG. 4) in the first embodiment. Is formed into a single sheet of the above-mentioned material, and is transformed into a square. A transparent plate 24 made of, for example, a disk-shaped transparent resin or glass and disposed around the front end of the shade 12 is provided on the inner side of the half-wave plate 20.
[0071]
As shown in FIG. 11, the half-wave plate 20 is installed in front of the first and second polarizing beam splitters 22 and 23, and passes through the first and second thin film stacks 16 and 17 to form a p-wave plate. This is conversion means for converting the vibration direction of the polarized light P by 90 degrees and converting the vibration so as to vibrate perpendicularly to the ground.
[0072]
The half-wave plate 20 is installed so as to be directly attached to the front surfaces of the first and second polarization beam splitters 22 and 23, but the front surface of the first and second polarization beam splitters 22 and 23 is provided. You may install it away from.
Further, a lamp cover or a lens made of a transparent body may be appropriately installed on the front surface of the light projecting device 15.
[0073]
According to the light projecting device of the second embodiment configured as described above, the operation is performed as follows.
When a fog lamp switch (not shown) is turned on, a light source (see FIG. 11) is turned on.
As shown in FIG. 11, the unpolarized light L emitted from the light source 2 is reflected by the spherical mirror 10 and irradiates the parabolic mirror 9 or irradiates the parabolic mirror 9 directly, Part of the unpolarized light L coming out of 2b is transmitted through the lamp cover 12c to illuminate the front. The non-polarized light L irradiated on the parabolic mirror 9 is reflected in a forward direction parallel to the optical axis O, and irradiates the first and second polarization beam splitters 22 and 23.
[0074]
The non-polarized light L enters the first and second polarization beam splitters 22 and 23 and is refracted so that the incident angle becomes the Brewster angle by the refractive index of the prism. When light enters the first and second thin film stacks 16 and 17 in the splitters 22 and 23 at a Brewster angle, the light is separated into p-polarized light P and s-polarized light S. The s-polarized light S is reflected and irradiates the first and second reflecting mirrors 18 and 19, and the p-polarized light P goes straight and irradiates the half-wave plate 20. The s-polarized light S is reflected by the first and second reflecting mirrors 18 and 19, becomes parallel to the optical axis O, and irradiates the front as first vertically polarized light.
[0075]
Further, the p-polarized light P separated by the first and second thin film stacks 16 and 17 is converted into a second vertically polarized light by the half-wave plate 20, and has a small reflectance in the vertical direction of the ground. The polarized light is irradiated forward.
[0076]
Since the light projecting device 15 illuminates the front with the first and second vertically polarized lights, the reflectance of the light that is diffused in the vertical direction with respect to the ground by the first and second vertically polarized lights is higher than that of the horizontally polarized lights. small. Therefore, the light projecting device 15 can significantly reduce the degree of the reflected light diffused in the vertical direction as compared with the conventional light projecting device that irradiates the non-polarized light L.
Therefore, for example, even in the case of heavy fog or heavy rain, it is possible to suppress reflected light that is diffused in the vertical direction due to water vapor particles and raindrops, and a forward visibility can be secured more than before. Further, since the light projecting device 15 has a square shape as a whole, the light projecting device 15 can have a simple structure and a high-performance configuration, and can be suitably used for a fog lamp.
[0077]
It should be noted that the present invention is not limited to the first and second embodiments described above, and various modifications and changes are possible within the scope of the technical idea, and the present invention relates to these modified and changed inventions. Of course.
For example, the light emitting devices 1 and 15 can be similarly irradiated with vertically polarized light by tilting the entire light emitting devices 1 and 15 by 90 degrees and providing conversion means in front of the reflection means instead of the front surface of the polarization beam splitter. It can be used as a lighting body.
[0078]
The light projecting devices 1 and 15 may be not only a headlight and a fog lamp of a vehicle but also a direction indicator lamp, a rear fog lamp, a stop lamp or a vehicle width lamp.
[0079]
Further, the light emitting devices 1 and 15 may be headlights of a motorcycle such as a motorcycle, or headlights of a boat such as a motor boat.
[0080]
【The invention's effect】
As described above, according to the light projecting device of the first aspect of the present invention, the polarization splitting means is divided and disposed around the light source, and each of the polarized light splitting means is polarized with respect to the p-polarized light transmitted therethrough. The direction of irradiation of the s-polarized light reflected by the separation means can be adjusted by reflection, and both the p-polarized light and the s-polarized light can be irradiated as forward polarized light in the forward direction. This converts all unpolarized light emitted from the light source into vertically polarized light, effectively utilizing light, suppressing vertical reflection, illuminating the front clearly, and securing the front view. Can be. In addition, by dividing and arranging the polarization separating means around the light source, the light projecting device can be made compact.
[0081]
According to the light projecting device of the second aspect of the present invention, the first and second polarization splitting means are arranged so as to be divided in a substantially horizontal direction, and the incident surface is formed so as to extend substantially horizontally. As a result, the s-polarized light separated and reflected by the first and second polarization separation means has a vibration plane of an electric field that is substantially perpendicular to the ground, and in that state, as the first vertical polarized light Available. Thereby, the oscillating plane in the vertical direction is converted by the conversion unit to the p-polarized light directly irradiated from the first and second polarization separation units, as compared with the s-polarized light irradiated through the reflection unit. The structure for providing the conversion means is simplified, and the size of the light projecting device can be further reduced.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view for explaining p-polarized light and s-polarized light.
FIGS. 2A and 2B are diagrams for explaining a difference between s-polarized light and p-polarized light and horizontal polarized light and vertical polarized light. FIG. 2A illustrates p-polarized light and s-polarized light when a polarization splitting unit is installed in parallel with the ground. (B) is a schematic side view showing the vibration directions of p-polarized light and s-polarized light when the polarization separation means is installed parallel to the ground, and (c) is a schematic side view showing the polarization direction of the polarization separation means. FIG. 4D is a schematic perspective view showing the vibration directions of the p-polarized light and the s-polarized light when installed at an angle with respect to the plane. FIG. It is a schematic side view shown.
FIG. 3 is a perspective view schematically showing a configuration of a light emitting device according to the first embodiment of the present invention.
FIG. 4 is a front view of the light projecting device shown in FIG.
FIG. 5 is a sectional view taken along line AA in FIG.
FIG. 6 is a view showing a light projecting device according to the first embodiment of the present invention, and is a schematic view showing a structure of a first thin film stack 3 installed in a first polarizing beam splitter.
FIGS. 7A and 7B are diagrams showing an example in which the light projecting device according to the first embodiment of the present invention is applied to a headlight of a vehicle, and FIG. 7A illustrates light emitted from the light projecting device during heavy fog and heavy rain; (B) is a schematic diagram showing a state of diffuse reflection occurring on the surface of a raindrop when light is emitted from a light projecting device.
FIG. 8 is a schematic front view showing a light emitting device according to a second embodiment of the present invention.
FIG. 9 is a schematic perspective view showing a light emitting device according to a second embodiment of the present invention.
FIG. 10 is a schematic perspective view showing a light emitting device according to a second embodiment of the present invention.
FIG. 11 is a schematic cross-sectional view showing a second embodiment of the present invention, and is a cross-sectional view as seen from line BB of FIG.
FIG. 6 is a schematic sectional view illustrating a light projecting device according to a second embodiment of the present invention.
FIG. 12 is a view showing a light projecting device according to a second embodiment of the present invention, and is a schematic perspective view of a first polarizing beam splitter.
FIG. 13 is a view showing a light projecting device according to a second embodiment of the present invention, and is a schematic perspective view of a second polarizing beam splitter.
14A and 14B are diagrams illustrating a state of light emitted from a headlight during heavy fog and heavy rain, where FIG. 14A is a schematic diagram illustrating a light distribution state of the headlight at that time, and FIG. It is a schematic diagram which shows the situation of the irregular reflection which arises on the surface of a raindrop.
[Explanation of symbols]
1,15 Floodlight device
2 Light source
3,16 First thin film lamination
4,17 Second thin film lamination
5. First half-wave plate (conversion means)
6. Second half-wave plate (conversion means)
7, 18 First reflection mirror (reflection means)
8, 19 Second reflecting mirror (reflecting means)
13,22 First polarization beam splitter (first polarization separation means)
14, 23 Second polarization beam splitter (second polarization separation means)
20 1/2 wavelength plate (conversion means)
L non-polarized
P p polarized light
S s polarized light

Claims (2)

A light source that emits unpolarized light,
A parabolic mirror for converting unpolarized light emitted from this light source into parallel rays,
It is arranged separately around the light source, separates non-polarized light from the parabolic mirror into p-polarized light and s-polarized light, and transmits the p-polarized light in the same direction as the incident direction of the non-polarized light, first and second polarization separation means for reflecting s-polarized light;
Reflecting means disposed on the outer periphery of the first and second polarized light separating means and reflecting the s-polarized light reflected by the first and second polarized light separating means in the same direction as the p-polarized light. When,
Irradiating one of the s-polarized light or the p-polarized light separated by the first and second polarization splitting means as a first vertically polarized light having a vibration plane of an electric field substantially perpendicular to the ground,
Either the p-polarized light or the s-polarized light is converted and irradiated as second perpendicular polarized light having a vibration plane of an electric field substantially perpendicular to the ground by a conversion means for converting a vibration plane of the electric field. Floodlight device. The polarized light separating unit has the first and second polarized light separating units that are arranged so as to be divided in a substantially horizontal direction, and that a non-polarized light incident surface emitted from the light source extends horizontally.
The p-polarized light separated by the first and second polarized light separating means is transmitted in the same direction as the non-polarized light, then converted by the converting means into the second vertical polarized light, and the first and second polarized lights are separated. 2. The s-polarized light separated by the polarization separation means is irradiated as a first vertical polarized light which is reflected in a substantially horizontal direction and then irradiated in the same direction as the p-polarized light by the reflection means. Floodlight device.

Images