JP2004354264A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system capable of improving illumination efficiency by suppressing surface reflection of light on a light entrance face of a translucent body and simultaneously heightening transmission efficiency of light entering the translucent body, concerning the lighting system applied to, for example, illumination of a display board or pointers of a vehicle instrument. <P>SOLUTION: This system is equipped with a light source 8 and the translucent body 6 having the light entrance face 61 for introducing light from the light source 8 to the inside. An optical interference film 9 for suppressing the surface reflection of incident light 61 is provided at least on the light entrance face 61 of the translucent body 6. The optical interference film 9 comprises a thin film formed by laminating, for example, a plurality of substantially transparent-and-colorless optical thin films having optical coherence, and each adjacent thin film has a different refractive index. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a lighting device applied to, for example, a display panel or a pointer of a vehicle instrument.
[0002]
[Prior art]
DESCRIPTION OF RELATED ART Conventionally, as an illuminating device which guides the light from a light source through a translucent body, the illuminating device of patent documents 1-3 below is known in the field of the instrument for vehicles, for example.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2003-021544 [Patent Document 2]
JP 2002-005697 A [Patent Document 3]
JP, 2002-267506, A
The illumination device described in Patent Document 1 illuminates the display panel by guiding light from a light source to the display panel via a light transmitting body. Further, in the lighting device described in Patent Document 2, the light-transmitting body itself is formed of a ring body decorating the circumference of the instrument, and light from a light source is introduced into this ring body to obtain a ring-shaped lighting design. The illumination device described in Patent Document 3 illuminates a pointer by introducing light from a light source into a linear translucent body constituting the pointer.
[0005]
[Problems to be solved by the invention]
However, the lighting device described in each of the above patent documents has a configuration in which light from the light source is introduced into the inside through the light-entering surface of the light-transmitting body, so that light loss due to surface reflection of the light-entering surface cannot be avoided, There is a problem that the lighting efficiency is reduced.
[0006]
The present invention has been made in view of this point, and a main object of the present invention is to provide a lighting device capable of suppressing surface reflection on a light incident surface and improving lighting efficiency.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a light source and a light transmitting body having a light incident surface for introducing light from the light source into the inside, and at least the light incident surface of the light transmitting body has a light incident surface. A light interference film for suppressing surface reflection is provided.
[0008]
The light-transmitting body has a reflection surface that reflects light introduced from the light-incident surface in a predetermined direction, and the reflection surface is an exposed surface that comes into contact with external air.
[0009]
A first light interference film comprising: a light source; and a light-transmitting member formed of a plate for introducing light from the light source into the light-transmitting member. And a light incident surface formed on the back surface side for introducing light from the light source into the inside, and light introduced from the light incident surface formed at a position facing the light incident surface in a plane direction of the light transmitting body. A reflecting surface that reflects the light, and a second light interference film that is formed on the back surface side to include the light incident surface and that suppresses the back surface reflection of external incident light and the front surface reflection of incident light from the light source. Features.
[0010]
The reflective surface is an exposed surface that comes into contact with external air.
[0011]
A light guide that condenses light from the light source and supplies the light to the light incident surface is disposed between the light incident surface and the light source.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a lighting device according to the present invention will be described with reference to the accompanying drawings.
[0013]
1 and 2 show a first embodiment of the present invention. FIG. 1 is a cross-sectional view of a lighting device, and FIG. 2 is a waveform diagram of a reflected light wave and a combined light wave.
[0014]
In FIG. 1, the lighting device according to the present embodiment generally includes a circuit board 1, a pointer driving device 2, a frame 3, a pointer 4, a display panel 5, and a light transmitting body 6.
[0015]
The circuit board 1 is a rigid substrate, and includes a light source 7 for illuminating the hands 4 and a light source 8 for illuminating the display panel 5 in addition to the hands driving device 2.
[0016]
The pointer driving device 2 is composed of, for example, a stepping motor and is disposed behind the circuit board 1, and the drive shaft 21 extends through the circuit board 1.
[0017]
The frame 3 is made of, for example, a white synthetic resin, and has a cylindrical portion 31 surrounding the drive shaft 21 and a reflecting portion 32 covering the back of the light transmitting body 6. In this case, the frame 3 is The display panel 5 is supported from behind.
[0018]
The pointer 4 is attached to the tip of the drive shaft 21, and indicates a later-described index portion of the display panel 5 by the rotation of the drive shaft 21. The pointer 4 has an indicator made of a translucent material, and when the light source 7 is turned on, the light is introduced into the indicator to emit light linearly.
[0019]
The display plate 5 is a well-known print panel in which an index portion 51, such as a scale or a number, to be indicated by the pointer 4 has transparency and a ground portion surrounding the indicator portion 51 has light shielding properties.
[0020]
The light transmitting body 6 is made of a substantially colorless and transparent light transmitting synthetic resin, and is formed in a substantially disk-shaped plate. The translucent body 6 is arranged so that a part of the back surface faces the light source 8 and the front surface faces the display panel 5, and the light from the light source 8 is introduced into a portion facing the light source 8. A light incident surface 61 is formed, and a reflection surface 62 that reflects light introduced from the light incident surface 61 in the plane direction of the light transmitting body 6 is formed at a position facing the light incident surface 61. .
[0021]
The back surface area of the light transmitting body 6 excluding the light incident surface 61 is covered with the reflecting portion 32 of the frame 3, thereby increasing the reflection efficiency, and introducing the light of the light source 8 from the light incident surface 61. The indicator portion 51 is transmitted and illuminated by reflecting the light in the plane direction by the reflecting surface 62 and further reflecting the light through the reflecting portion 32.
[0022]
Here, the light interference film 9 that suppresses surface reflection of incident light by utilizing the coherence of light (light wave) is formed on the incident surface 61. In this example, the light interference film 9 is not formed except for the incident surface 61.
[0023]
The light interference film 9 is, for example, a thin film obtained by laminating a plurality of optical thin films having substantially coherent and colorless optical coherence, and the adjacent thin films have different refractive indexes. These optical thin films are formed by, for example, vacuum evaporation or sputtering so that titanium oxide (titanium compound) having a large refractive index of the material itself and silicon oxide (silicon compound) having a refractive index of the material itself smaller than titanium oxide alternately overlap. It is formed using a film forming method such as a dipping method or a dipping method. The total thickness of the light interference film is 1 micron or less in this example.
[0024]
When light from the light source 8 is incident on the optical interference film 9 configured as described above, the light is transmitted to the interface between the air and the optical thin film, the interface between the optical thin films, the optical thin film and the light transmitting body 6 (light incident). At the interface with the surface 61), the reflected light is reflected at the interface and separate reflected light is generated. By optimally combining each optical thin film and the refractive index (material), the amplitude of the combined light wave generated by interference between the reflected light light waves is reduced. The phase control of the reflected light (light wave) is performed so as to reduce the reflectance, so that the reflectance of the light reflected through the optical interference film 9 is reduced, and the transmittance of the incident light entering the light transmitting body 6 is increased. Has become.
[0025]
Specifically, it is assumed that, for example, reflected light (light wave) W1 shown in FIG. 2A and reflected light (light wave) W2 shown in FIG. 2B are generated by light reflection through the light interference film 9. At this time, since the phases of the reflected lights W1 and W2 are controlled to be different from each other, the amplitude (= intensity) of the combined light wave (reflected light) W3 generated by the optical interference between the reflected lights W1 and W2 is as shown in FIG. As shown in (c), the amplitude of the reflected light W1 and W2 is combined, thereby reducing the intensity of the reflected light. Since the transmittance is inversely proportional to the light reflectance, the intensity of the transmitted light entering the light transmitting body 6 is increased, and as a result, the illumination efficiency is improved.
[0026]
The light interference film 9 is composed of a plurality of optical thin films because the film thickness and the refractive index (material) of each optical thin film are fixed, so that the reflectivity depends on the line of sight of the observer and the wavelength of the reflected light. This is for maintaining low reflectance over a wide wavelength range by using a plurality of layers.
[0027]
As described above, in the present embodiment, the light source 8 and the light transmitting body 6 having the light incident surface 61 for introducing light from the light source 8 into the inside are provided. By providing the light interference film 9 for suppressing the surface reflection of the incident light 61, the transmittance is improved by the amount corresponding to the suppression of the surface reflection of the light incident surface 61, whereby the illumination efficiency can be improved.
[0028]
Further, in the present embodiment, the light interference film 9 is provided only on the light incident surface 61 and the reflection surface 62 is an exposed surface that is in contact with the outside air, thereby preventing a decrease in the reflectance of the reflection surface 62 due to the light interference film 9. Can be.
[0029]
3 and 4 show a second embodiment of the present invention. FIG. 3 is a sectional view of a lighting device according to the present embodiment, and FIG. 4 is a developed view of a light guide used in the present embodiment. In the present embodiment, an example is shown in which the light transmitting body 6 itself also functions as a display body.
[0030]
That is, in this example, the first display panel 501 in which the display panel 5 is located on the drive shaft 21 side, and the second display panel 502 which is separated from the first display panel 501 by a predetermined distance are provided. The first and second display panels 501 and 502 are constituted by a third display panel 503 which is arranged separately in the thickness direction, and each of the display panels 501, 502 and 503 has a donut shape. Is formed.
[0031]
An indicator 51 is formed on the second display plate 502, and the indicator 51 is the same as in the first embodiment.
[0032]
The light transmitting body 6 is arranged so as to be exposed from a gap (the shape is a donut shape) between the display plates 501 and 502 and to be visually recognized by an observer.
[0033]
In this case, a first light interference film 91 that suppresses surface reflection of external incident light such as natural light is formed on the front side of the light transmitting body 6, and the light is opposed to the light source 8 on the rear side and the light is internally reflected. A light incident surface 61 for introducing light into the light transmitting surface 6 is provided, and a reflection surface 62 is formed at a position facing the light incident surface 61. The tilt angle with respect to the plane direction is set so that the light can be totally reflected in the direction. In this example, the tilt angle is approximately 45 and the lens is exposed to the outside air. In addition, a second light interference film 92 is formed on the back surface of the light transmitting body 6 so as to include the light incident surface 61 and suppress the back surface reflection of external incident light and the front surface reflection of incident light from the light source 6. The light interference films 91 and 92 themselves are the same as the light interference films applied in the first embodiment.
[0034]
Further, between the light incident surface 61 of the light transmitting body 6 and the light source 8, a light guide 10 for condensing the light of the light source 8 and irradiating the light to the light transmitting body 6 is formed. In this case, a plurality of light sources 8 are arranged on a concentric circle with respect to the drive shaft 21, and the structure of the light guide 10 itself is cylindrical, but as shown in FIG. Are provided on the light source 8 side (incident side) and the light transmitting body 6 side (irradiation side) so that the light guide 10 is a point light source. The light from the light source 8 is condensed so as to approach parallel light along the drive shaft 21, and is emitted toward the light transmitting body 6.
[0035]
The third display panel 503 is arranged behind the light transmitting body 6 and constitutes the background of the index portion 51 and the exposed area of the light transmitting body 6 (any color is possible).
[0036]
In such a configuration, when the light source 8 is not turned on, the display color of the third display panel 503 is visually recognized by the observer through the indicator 51 and the exposed area of the light transmitting body 6 by the external incident light. At this time, first and second light interference films 91 and 92 are formed on the front and back surfaces of the light transmitting body 6, respectively, to reflect external incident light entering from the front side of the light transmitting body 6 and to prevent the light transmitting body 6 from being reflected. Since the reflection of the external incident light which enters from the front side and advances in the light transmitting body 6 and reaches the rear surface of the light transmitting body 6 is suppressed, the glare due to the external light reflection of the light transmitting body 6 is suppressed. Thereby, the display color of the third display panel 503 can be clearly recognized through the light transmitting body 6.
[0037]
On the other hand, when the light source 8 is turned on, the light is condensed through the light guide 10 so as to approach parallel light, and enters the light transmitting body 6 through the second light interference film 92 and the light incident surface 61. At this time, since the second light interference film 92 suppresses surface reflection on the light incident surface 61, the efficiency of incidence into the light transmitting body 6 is improved. The light that has entered the light transmitting body 6 as described above is reflected in the plane direction of the light transmitting body 6 through the reflecting surface 62. At this time, the reflecting surface 62 is set so as to totally reflect the light condensed into parallel light through the light guide 10 at an angle of about 90 degrees while maintaining the parallel state. Most of the light reflected through 62 comes closer to the plane direction of the light transmitting body 6, and as a result, the incident angle of the light reaching the rear surface of the light transmitting body 6 becomes shallower. Even when the second light interference film 92 is present on the whole and light is likely to pass out of the light transmitting body 6, it is difficult to pass light, and light can be efficiently transmitted to the index portion 51 relatively far from the light entrance surface 61. Can be guided.
[0038]
As described above, according to the present embodiment, the light source 8 and the light transmissive body 6 formed of a plate for introducing the light from the light source 8 into the inside are provided. A first light interference film 91 for suppressing surface reflection of incident light, a light incident surface 61 formed on the back surface side for introducing light of the light source 8 into the inside, and a position facing the light incident surface 61. A reflecting surface 62 for reflecting the light introduced from the light incident surface 61 in the plane direction of the light transmitting body 6, and a rear surface reflecting external incident light formed on the rear surface so as to include the light incident surface 61 and incident from the light source 8. By having the second light interference film 92 that suppresses surface reflection of light, the transmittance is reduced by the surface interference of the light entrance surface 61 by the light interference film 91 as in the first embodiment. And thus the lighting efficiency can be improved.
[0039]
Further, in the present embodiment, by providing the light interference films 91 and 92 on the front and back surfaces of the light transmitting body 6, even when the light transmitting body 6 is used as a display body, reflection of external incident light can be suppressed, and display quality can be improved. Can be improved.
[0040]
Further, in the present embodiment, the light guide 10 that collects light from the light source 8 and supplies the light to the light incident surface is disposed between the light incident surface 61 and the light source 8, so that the light is supplied to the light incident surface 61. Lighting efficiency can be increased by bringing light closer to parallel light. Further, by combining such a light guide 10 with a reflecting surface 62 that reflects the introduced light in a plane direction, even when the light interference film 92 is present in addition to the light incident surface 61, it is possible to suppress light leakage. , Efficient lighting can be performed.
[0041]
In the first and second embodiments, the present invention is applied to the display panel illumination of the instrument. However, the pointer illumination of the instrument, the illumination of the decorative body such as a ring, the illumination of the display such as a liquid crystal panel, the various alarm notifications. The present invention can be applied not only to an instrument, but also to all lighting devices to which a light source and a light-transmitting member are applied, in addition to being applicable to lighting of a device.
[0042]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to provide a lighting device that can achieve the intended purpose, suppress surface reflection of a light incident surface, and improve lighting efficiency. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a lighting device according to a first embodiment of the present invention.
FIGS. 2A and 2B are diagrams illustrating a function of an optical interference film applied to the embodiment, in which FIGS. 2A and 2B are waveform diagrams illustrating light waves of reflected light, and FIG.
FIG. 3 is a cross-sectional view of a lighting device according to a second embodiment of the present invention.
FIG. 4 is a development view of a light guide applied to the embodiment.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 circuit board 2 pointer driving device 3 frame 4 pointer 5 display panel 6 translucent member 7 light source 8 light source 9 light interference film 10 light guide 11 convex lens 21 drive shaft 31 cylindrical portion 32 reflecting portion 51 indicator portion 61 light entrance surface 62 Reflecting surface 91 First light interference film 92 Second light interference film 501 First display plate 502 Second display plate 503 Third display plate

Claims (5)

A light source,
A light-transmitting body having a light incident surface for introducing light from the light source into the inside,
An illumination device, wherein an optical interference film for suppressing surface reflection of incident light is provided on at least the light incident surface of the light transmitting body. The lighting device according to claim 1, wherein the translucent body has a reflecting surface that reflects the light introduced from the light incident surface in a predetermined direction, and the reflecting surface is an exposed surface that comes into contact with external air. A light source,
A light transmitting body made of a plate body for introducing light from the light source into the inside,
A first light interference film formed on the front surface of the light transmitting member to suppress surface reflection of external incident light; a light incident surface formed on the back surface of the light transmitting surface for introducing light of the light source therein; A reflecting surface formed at a position facing the light surface and reflecting the light introduced from the light incident surface in a plane direction of the light transmitting body, and a light incident surface formed on the back surface thereof so as to include the light incident surface. A lighting device, comprising: a second light interference film for suppressing back reflection and front reflection of incident light from the light source. The lighting device according to claim 3, wherein the reflection surface is an exposed surface that is in contact with external air. The lighting device according to claim 4, wherein a light guide that condenses light from the light source and supplies the light to the light incident surface is disposed between the light incident surface and the light source.

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