JP2006019027A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system capable of carrying out illumination without luminance irregularity, in a lighting system using a plurality of light sources. <P>SOLUTION: This lighting system is provided with: a plurality of light emitting diodes 4 mounted in a predetermined range on a surface of a wiring board 3; and a lens array 2 composed by forming lens parts 2a for refracting illumination light emitted from the light emitting diodes 4 by making them correspond to the respective light emitting diodes 4. The lens parts 2a formed on the outside are so mounted as to tilt the center axis (x) of each lens part 2a with respect to the optical axis (y) of the corresponding light emitting diodes 4, and each light emitting diode 4 is so mounted as to be positioned on a focal point of the corresponding lens part 2a or in the vicinity of the focal point. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an illumination device that illuminates an object to be illuminated, and is suitable, for example, as an illumination device used in a vehicle head-up display.

  Conventionally, a display device as shown in FIG. 6 is known, and a liquid crystal display element 10 in which a polarizing member is attached to the front and back surfaces of a liquid crystal cell in which liquid crystal is sealed in a pair of translucent substrates, and a hard wiring board 11. A light source 12 that illuminates the liquid crystal display element 10 is connected to the vehicle, and a display image emitted from the liquid crystal display element 10 illuminated by the light source 12 is reflected by a reflecting mirror 13. And the like are projected on the display unit 14 (see, for example, Patent Document 1). Such a display device is called a head-up display.

  Since such a display device has a structure for projecting onto the display unit 14, a large amount of light is emitted such that a part of the light is transmitted at the time of projection or a part other than necessary is illuminated in the display device. There was a problem of loss. Further, since it is necessary to project a display image with good contrast even in the daytime, it is necessary to illuminate the liquid crystal display element 10 with the light source 12 having high luminance. Therefore, it has been desired to efficiently illuminate using a plurality of light sources with high directivities such as light emitting diodes.

On the other hand, the display image projected on the display unit 14 is desired to be displayed larger, and the display device is desired to be miniaturized. By using a concave reflecting mirror (concave reflector) 13, The display image of the liquid crystal display element 10 was enlarged and displayed.
Japanese Patent Laid-Open No. 10-48565

  However, by using a light source with high directivity as in such a display device, the illumination efficiency increases, but the illumination light from the light source is concentrated and emitted in the front direction. Therefore, when performing wide-angle display in order to project a large display image, there has been a problem that the outer luminance of the display image projected on the display unit is lower than the inner luminance, resulting in poor appearance. .

  Accordingly, an object of the present invention is made by paying attention to the above-described problem, and an object of the present invention is to provide an illuminating device that can perform illumination without uneven brightness in an illuminating device using a plurality of light sources.

  In the illumination device of the present invention, as described in claim 1, a plurality of light sources provided within a predetermined range of the wiring board surface and a lens unit that refracts illumination light emitted from the light sources correspond to the light sources. A lens unit formed outside, the lens unit formed outside is provided with a central axis of the lens unit inclined with respect to the optical axis of the light source, and The light source is provided so as to be positioned on or near the focal point of the lens unit.

  Further, as described in claim 2, in the illumination device according to claim 1, the radius of curvature of the lens portion formed on the outside is smaller than the radius of curvature of the lens portion formed on the inside. It is characterized by being formed.

  Further, as described in claim 3, in the illumination device according to claim 1, an illuminated member that is transmitted and illuminated by illumination light emitted from the light source through the collective lens, and the illuminated member And a magnifying member that refracts or reflects transmitted light to enlarge and displays the enlarged light.

Further, according to the illumination device of the present invention, as described in claim 4, each of the light sources includes a plurality of light sources provided within a predetermined range of the wiring board surface and a lens unit that refracts illumination light emitted from the light sources. An illuminating device comprising a collective lens formed corresponding to
The lens part formed on the outer side is provided such that the central axis of the lens part is inclined with respect to the optical axis of the light source, and the light source is provided at a position intersecting the central axis of the lens part. It is a feature.

  The present invention can provide an illuminating device that can illuminate an object to be illuminated with a plurality of light sources and can perform illumination without uneven brightness.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings by taking as an example a display device for a vehicle head-up display that displays vehicle speed, engine speed, and the like.

  FIG. 1 shows a vehicle head-up display mounted on a vehicle, and a display image projected by a display device C provided on an upper dashboard B of the vehicle A is observed by a windshield (display unit) D surface. The structure is reflected in the direction of the person E. The observer E can observe the display image as a virtual image V superimposed on the landscape.

  The display device C according to the embodiment of the present invention is provided so as to be embedded in the upper part of the dashboard B, and will be described with reference to FIG. The display device C includes a lens array (collective lens) 2, a wiring board 3, a light emitting diode (light source) 4, a liquid crystal display element (illuminated member) 5, and a cylindrical reflection provided in the housing 1. It is mainly composed of a member 6 and a concave mirror (enlarged member) 7.

  The housing 1 is made of a light-shielding synthetic resin material, and is provided with an opening 1a that opens an upper portion (front glass side) of the position where the concave mirror 7 is disposed. In addition, a light shielding wall 1 b is formed in the housing 1 integrally with the housing 1 to prevent the sunlight from entering a liquid crystal display element (to be described later) and making the virtual image V difficult to see (washout). The housing 1 is provided with a translucent cover 1c made of a translucent synthetic resin material (for example, acrylic), and is disposed so as to close the opening 1a.

  The lens array 2 is made of a translucent synthetic resin material (for example, acrylic) and is disposed in the housing 1. The lens array 2 is formed with a plurality of convex spherical surfaces, and the illumination light from the light-emitting diode 4 is refracted by the spherical surfaces to uniformly illuminate a liquid crystal display element (to be described later) serving as a member to be illuminated. Light can be irradiated.

  The wiring substrate 3 is preferably an aluminum substrate having high thermal conductivity, and is disposed in the housing 1 so as to be parallel to the lens array 2 at a predetermined interval. The wiring board 3 mounts at least an electronic component such as the light emitting diode 4 and is provided with wiring for supplying power to the electronic component. The predetermined interval differs depending on the directivity of the light emitting diode 4 and the spherical shape of the lens array 2, and is selected such that there is no luminance unevenness.

  The LED 4 can be a chip LED, and is mounted within a predetermined range on the surface of the wiring substrate 3 on the lens array 2 side so that the optical axis is substantially perpendicular to the surface of the wiring substrate 3. Further, the light emitting diodes 4 having narrow directivity (20 degrees to 30 degrees in the present embodiment) are used, and are disposed at positions corresponding to the spherical surface of the lens array 2.

  The liquid crystal display element 5 has a polarizing member attached to the front and back surfaces of a liquid crystal cell in which liquid crystal is sealed in a pair of translucent substrates. The liquid crystal display element 5 is provided in the housing 1 and is disposed at a position where the illumination light from the light emitting diode 4 reaches via the lens array 2. The illumination light transmitted through the liquid crystal display element 5 is projected onto the concave mirror 7 as a display image. The liquid crystal display element 5 includes an arithmetic circuit (not shown) that measures the vehicle speed and the engine speed based on output signals from a vehicle speed sensor and an engine rotation sensor provided in the vehicle A, and a liquid crystal that drives the liquid crystal based on the calculation result. The measured values of the speed of the vehicle A and the engine speed can be expressed as numerical values by a drive circuit (not shown).

  The cylindrical reflecting member 6 is formed in a cylindrical shape having both ends opened with a white synthetic resin material, provided so that one opening is closed by the liquid crystal display element 5, and the light emitting diode 4 from the other opening side. The illumination light is arranged so as to be incident through the lens array 2. Therefore, the cylindrical reflecting member 6 prevents the illumination light from the light emitting diode 4 from being reflected on the inner wall of the cylindrical reflecting member 6 and leaking to other than the liquid crystal display element 5 and being directed to the liquid crystal display element 3 side. It is arranged so as to collect light, and efficient illumination can be obtained.

  The concave mirror 7 is provided in the housing 1 below the opening 1a, and reflects a display image projected through a liquid crystal display element 5 described later to the windshield D side. The angle is adjustable so that it can be easily seen. The concave mirror 7 is formed of a reflective surface 7a having a predetermined curvature in order to enlarge and display the display image on the windshield D.

  Next, an illumination structure that is a main part of the present invention will be described with reference to FIGS.

  The lens array 2 is provided with lens portions 2 a formed corresponding to the respective light emitting diodes 4. The lens portion 2a has a smooth incident surface 2b on which the illumination light from the light emitting diode 4 is incident, and a convex spherical surface 2c that transmits the illumination light and is provided on the opposite side of the incident surface. The liquid crystal display element 5 is irradiated (emitted) with desired refraction. In the lens array 2, the lens unit 2 a formed on the outside is provided with the central axis x of the lens unit 2 a inclined with respect to the optical axis y of the light emitting diode 4.

  The spherical surface 2c of the lens array 2 is set according to the material (refractive index) of the lens array 2 and the distance from the light emitting diode 4 and the incident surface 2b of the lens array 2, and the illumination light from the light emitting diode 4 It is formed with such a curvature and size that the liquid crystal display element 5 is irradiated so as not to be uneven. In this case, the curvature radius of the curved surface 2c of the lens portion 2a formed on the outside is formed in a shape smaller than the curvature radius of the curved surface 2c of the lens portion 2a formed on the inside. That is, the curved surface 2c of the outer lens portion 2a is formed with a smaller focal length than the curved surface 2c of the inner lens portion 2a.

  The light emitting diode 4 is disposed such that the optical axis y is substantially perpendicular to the surface of the wiring substrate 3 and the surface of the lens array 2 provided in parallel with the wiring substrate 3. The light emitting diodes 4 are provided corresponding to the respective spherical surfaces 2c, and are provided so as to intersect the central axis x of the respective spherical surfaces 2c. In this case, the light emitting part of the light emitting diode 4 is provided so as to be located on or near the focal point of the lens part 2a.

  Therefore, as shown in FIG. 3, the illumination light of the light emitting diodes 4 provided on the outside has many components that are refracted to the outside (end direction) by the corresponding spherical surface 2b. As shown in FIG. 4, the display image has a uniform brightness with respect to the reflection surface 7a of the concave mirror 7 not only on the front surface side (inside the reflection surface 7a) but also outside the liquid crystal display element 5. Can be projected.

  In the illumination structure of such a display device, a plurality of light emitting diodes 4 provided within a predetermined range on the surface of the wiring board 3 and a lens portion 2 a that refracts illumination light emitted from the light emitting diodes 4 correspond to each light emitting diode 4. The lens unit 2a formed outside is provided with the central axis x of the lens unit 2a inclined with respect to the optical axis y of the light-emitting diode 4. By providing the light emitting diode 4 so as to be positioned on or near the focal point of the lens unit 2a, illumination without unevenness in luminance can be performed.

  In addition, a liquid crystal display element 5 that is transmitted and illuminated by illumination light emitted from the light emitting diode 4 through the lens array 2 and a concave mirror 7 that reflects and transmits the transmitted light that passes through the liquid crystal display element 5 are provided. As a result, even when the display image is enlarged, it is possible to prevent the outer luminance of the display image from being lower than the inner luminance, and display with good appearance by illumination without luminance unevenness. be able to.

  The lens array 2 shown in the embodiment of the present invention has been described by taking an example in which the incident surface 2b is smooth. However, the present invention is not limited to this, for example, the incident surface is a spherical surface. It may have a concave surface or a convex surface corresponding to the position.

  Further, as shown in FIG. 5, a plurality of light emitting diodes 40 provided within a predetermined range on the surface of the wiring board 30 and a lens portion 20 a that refracts illumination light emitted from the light emitting diodes 40 correspond to each light emitting diode 40. The lens unit 20a formed on the outside is provided with the central axis v of the lens unit 20a inclined with respect to the optical axis w of the light emitting diode 40. In addition, the light emitting diode 40 may be provided at a position where it intersects the central axis v of the lens portion 20a, and each incident surface 20b may be inclined and uneven, as in the above-described embodiment. The effect is obtained.

  In addition, for example, by providing a lens array having a spherical surface in the form of a honeycomb and arranging the light emitting diodes in alignment with the corresponding positions, the light emitting diodes can be densely arranged, so that high-intensity illumination can be achieved. Even in this case, by applying the present invention, the same effects as those of the above-described embodiment can be obtained.

  Further, the display device C according to the embodiment of the present invention described above has been described by taking as an example a structure in which a display image to be projected is reflected by the windshield D in the direction of the viewer E. The part is displayed not by the windshield D, but by a rigid reflector fixedly provided on the dust board B or the housing 1 or a translucent reflector (combiner) attached to the inner surface of the windshield 4. A structure that reflects an image in the direction of an observer may be used.

  Further, in addition to the configuration of the present invention, by providing a concave lens between the concave mirror and the liquid crystal display element, or between the liquid crystal display element and the light source, even when the enlarged display is performed at a larger ratio, the luminance unevenness is reduced. It becomes possible to prevent.

  Moreover, although the present invention has shown what is enlarged and displayed by the concave mirror 7, it may be enlarged and displayed by refraction by a lens.

  Further, in the embodiment of the present invention, the display device C described above has been described as an example, but the present invention is not limited to this, and the configuration may be any as long as the same effect can be obtained. For example, it is sufficient if a plurality of light sources are provided, and a point light source such as a bulb or a linear light source such as a cold cathode tube may be used.

The figure which shows the structure of the head-up display mounted in the vehicle in embodiment of this invention. The figure which shows the main structures of the display apparatus in embodiment same as the above. The figure which shows the illumination structure of the display apparatus in embodiment same as the above. The figure which shows the illumination structure of the display apparatus in embodiment same as the above. The figure which shows another example of the illumination structure in embodiment same as the above. The figure which shows a prior art example.

Explanation of symbols

2 Lens array (collective lens)
2a Lens part 2b Incident surface 2c Spherical surface 3 Wiring board 4 Light emitting diode (light source)
5 Liquid crystal display element (illuminated member)
7 Concave mirror (enlarged member)
x Center axis y Optical axis

Claims (4)

  An illumination device comprising: a plurality of light sources provided within a predetermined range of a wiring board surface; and a collective lens in which lens portions that refract illumination light emitted from the light sources are formed corresponding to the light sources. The lens portion formed on the outside is provided such that the central axis of the lens portion is inclined with respect to the optical axis of the light source, and the light source is positioned on or near the focal point of the lens unit. An illuminating device characterized by being provided.   The lighting device according to claim 1, wherein a radius of curvature of the lens portion formed outside is formed in a shape smaller than a radius of curvature of the lens portion formed inside.   An illuminated member that is transmitted and illuminated by illumination light emitted from the light source through the collective lens, and an enlarged member that refracts or reflects the transmitted light that is transmitted through the illuminated member and displays the enlarged image. The lighting device according to claim 1. An illumination device comprising: a plurality of light sources provided within a predetermined range of a wiring board surface; and a collective lens in which lens portions that refract illumination light emitted from the light sources are formed corresponding to the light sources. The lens portion formed on the outside is provided such that the central axis of the lens portion is inclined with respect to the optical axis of the light source, and the light source is provided at a position where it intersects the central axis of the lens portion. A lighting device characterized by that.

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