JP4119216B2 - Lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lighting device including a light guide plate.
[0002]
[Prior art]
Conventionally, in a reflective liquid crystal display device that displays using ambient light as a light source, the brightness depends on the amount of ambient light, so in environments where sufficient ambient light cannot be obtained, such as when used in a dark place, The visibility of the display is extremely reduced. Therefore, a liquid crystal display device has been proposed in which a front light (surface emitting illumination device) is provided on the front side of a reflective liquid crystal display unit (liquid crystal display element) and used as an auxiliary light source. The liquid crystal display device equipped with this front light operates as a normal reflection type liquid crystal display device in an environment where sufficient ambient light can be obtained such as outdoors in the daytime, and the front light is turned on as a light source if necessary. It is.
[0003]
The front light includes a light guide plate having a reflective surface formed of a large number of fine grooves on the surface in order to uniformly illuminate the surface of the liquid crystal display unit uniformly. Due to the action of the reflecting surface, it is possible to illuminate a wide surface with uniform brightness even when a point light source or a line light source is used as the light source. (For example, refer to Patent Document 1).
[0004]
[Patent Document 1]
JP 2000-180631 A
[Problems to be solved by the invention]
The use of the front light for various purposes is being studied as an efficient illumination means with excellent illumination capability. In view of such a current situation, a front light having a more appropriate lighting capability according to each application has been desired.
[0006]
The present invention was made in view of the above circumstances, and an object thereof is to provide an efficient and uniformly irradiated possible lighting apparatus illuminating light only to the area which needs to be illuminated.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, an incident surface for introducing light emitted from a light source, an exit surface for emitting the light, and directing light introduced from the incident surface toward the exit surface A light guide plate comprising a base surface on which a reflection area having fine grooves to be reflected is formed, and a light guide part for propagating light between the incident surface and the output surface, and an incident surface of the light guide plate A plurality of light sources for introducing light into the light source plate, and a plurality of the reflection areas are formed on the base surface with an area smaller than an area of the base surface, and a portion between the reflection areas in the light guide plate is formed in a flat plate shape. Each of the light sources can be illuminated through a plurality of the reflection areas, and the direction of the emitted light can be visually recognized from the base surface side through the plurality of reflection areas and a portion between them. Is provided.
[0008]
According to such an illuminating device, the illumination light emitted from the emission surface illuminates only the same range as the shape of the plurality of reflection areas. Moreover, the illumination range can be visually recognized from the base surface side through these reflection areas. By forming the reflective area in a size smaller than the base surface, forming multiple on the base surface, and limiting the illumination range to the case where the reflective surface is formed on the entire base surface, multiple areas that actually require illumination It is possible to illuminate only the area. By not irradiating illumination light around the area where illumination is necessary, the difference in contrast between the peripheral portion and the illumination range is increased, and the visibility of the plurality of illumination ranges is further enhanced. The reflective area may be formed in a circular shape. The reflection area may be formed at a central portion of the base surface. Furthermore, it is possible to make the emission direction visible from the base surface side through the plurality of reflection areas and the portion between them.
[0009]
According to such a configuration, it becomes possible to efficiently and clearly illuminate a circular object such as a meter or a clock face. If such a light guide plate and a light source are provided in an illuminating device, it is possible to provide an illuminating device capable of efficiently and clearly illuminating an object to be illuminated having an arbitrary shape. Furthermore, a circular object to be illuminated in the illumination range by the emitted light, such as a meter or a clock face, can be visually recognized from the base surface side through the plurality of reflection areas and a portion between them .
Further, a bar light guide in contact with the incident surface is provided outside the incident surface of the light guide plate, a light emitting element is disposed at an end of the bar light guide, and one side surface of the bar light guide Is opposed to the incident surface, and among the side surfaces of the bar light guide, the side surface opposite to the incident surface is a reflective surface in which a plurality of wedge-shaped grooves are formed. Is provided.
The bar light guide body changes the light propagation direction to the light guide plate side by reflecting the light emitted from the light emitting element and introduced into the inside by the side surface constituting the wedge-shaped groove, and the incident surface of the light guide plate Is designed to emit light. The light introduced from the bar light guide into the light guide plate propagates inside the light guide unit, is reflected by the surfaces constituting the prism grooves formed in the reflection area, and its propagation direction is changed. The light is emitted from the emission surface.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partial perspective view of a front light (illumination device) which is a basic form of the illumination device, and FIG. 2 is an exploded perspective view of the front light shown in FIG. The front light (illuminating device) 10 includes a flat light guide plate 12 made of a transparent resin material, and a bar guide in contact with an incident surface 12a of the light guide plate 12 (one end portion on the short side of the rectangular light guide plate 12). Light body 13, light emitting elements (light sources) 15 and 15 provided at both ends in the length direction of bar light guide 13, and incident surfaces of bar light guide body 13, light emitting elements 15 and 15, and light guide plate 12 The cover member 18 is attached so as to cover the side end portion on the 12a side. The light emitting element 15 may be one or three or more.
[0011]
The light guide plate 12 includes a transparent flat plate-shaped light guide unit 11, an incident surface 12a for introducing light into the light guide unit 11, a base surface (upper surface) 12d connected to the incident surface 12a at a right angle, and the base. A reflection area (reflection surface) 12c formed of a plurality of fine grooves 14 formed in a part of the surface 12d and having a wedge shape in cross section is provided. The reflection area (reflection surface) 12c propagates and reflects light propagating through the light guide unit 11. With such a configuration, the light guide plate 12 reflects light introduced into the inside from the incident surface 12a by the reflection area 12c, changes the propagation direction thereof, and emits the light from the emission surface 12b on the opposite side of the reflection area 12c. Has been.
[0012]
As is clear from FIGS. 1 and 2, the reflective area 12c formed on the base surface 12d is formed to be smaller than the base surface 12d. Such a reflection area 12c should just be formed in the same shape as the shape which divides only the range which needs illumination among the to-be-illuminated objects illuminated using the front light 10. FIG. For example, if the range requiring illumination is a circle, the reflection area 12c is formed in a circle. The light guide plate 12 is formed by injection molding a resin material such as a transparent acrylic resin into a flat plate shape, and then forming a reflection area 12c in a part of the base surface 12d that represents a range that needs to be illuminated among objects to be illuminated. do it. As a material constituting the light guide plate 12, transparent resin materials such as polycarbonate resin and epoxy resin, glass, and the like can be used in addition to acrylic resin.
[0013]
In this way, if the shape of the reflection area 12c is formed in a shape that divides only an area to be illuminated in the object to be illuminated, for example, a circle, the illumination light emitted from the emission surface 12b is the same as the shape of the reflection area 12c. Only the range is illuminated as the illumination range 21. The reflective area 12c is formed in a size smaller than the base surface 12d, and the illumination range 21 is limited as compared to the case where the reflective surface is formed on the entire base surface 12d, thereby illuminating only the range that actually needs illumination. It becomes possible. The visibility of the illumination range 21 is enhanced by not irradiating illumination light around the area that needs illumination.
[0014]
As shown in FIG. 2, the bar light guide 13 is a substantially quadrangular column-shaped transparent member made of, for example, an acrylic resin or a polycarbonate resin, and has a side surface 13 a and an incident surface 12 a of the light guide plate 12. It arrange | positions along the light-guide plate 12 side end surface so that it may oppose. Further, one or a plurality of light emitting elements 15 and 15 are disposed at both ends in the length direction of the bar light guide 13. Of the side surfaces of the light guide 13, the side surface opposite to the light guide plate 12 is a reflecting surface 13 b in which a plurality of wedge-shaped grooves 16 are formed, as shown in FIG. This direction is parallel to the end face on which the light emitting element 15 is provided.
[0015]
The bar light guide 13 changes the propagation direction of light toward the light guide plate 12 by reflecting the light emitted from the light emitting elements 15 and 15 and introduced into the inside thereof by the surface constituting the groove 16. The incident surface 12a of the light guide plate 12 is irradiated with light. The light introduced from the bar light guide 13 into the light guide plate 12 propagates inside the light guide 11 and is reflected by the surface constituting the prism groove 14 formed in the reflection area 12c, and the propagation direction thereof is changed. It is changed and is emitted from the emission surface 12 b of the light guide plate 12.
[0016]
The light emitting element 15 is disposed with its light emitting surface facing the side end surface of the bar light guide 13. Here, the light emitting element 15 provided in the front light of the present embodiment will be described with reference to FIG. The light emitting element 15 shown in FIG. 3 includes a substrate 35, LEDs (light emitting diodes) 15R, 15G, and 15B arranged in the center of the substrate 35, and a resin condensing lens formed so as to cover these LEDs. 37 and power supply terminals 36, 36 formed on the substrate 35 on both sides of the condenser lens 37, and emits light toward the front side in the figure (the side where the LEDs are disposed). It has become. Although not shown, signal terminals for controlling the light emission intensity of the LEDs 15R, 15G, and 15B are also provided on the substrate 35. Alternatively, there is one that obtains white light by applying a yellow phosphor to a light emitting portion of one blue LED.
[0017]
The LEDs 15R, 15G, and 15B are diodes having emission colors of red, green, and blue, respectively. By controlling the emission intensity ratio of these LEDs, additive color mixing is performed in the condenser lens 37, and the lens 37 The condensed light can be applied to the end surface of the bar light guide 13. By including the light emitting element 15 having such a configuration, the front light of the present embodiment can control the illumination light with various color tones.
[0018]
In the light emitting element 15 shown in FIG. 3, light emitting bodies of red, green, and blue light emission colors are arranged in a row in the vertical direction from the lower side of the drawing, but the arrangement direction and arrangement order are not particularly limited, and each LED May be arranged in three directions. In addition to the three color LEDs, a white LED may be further provided to increase the luminance. Further, the condensing lens 37 is not limited to the shape shown in FIG. 3 and can be appropriately changed to a substantially hemispherical one.
[0019]
Further, in the present embodiment, the light emission intensity of the RGB LEDs 15R, 15G, and 15B can be freely changed. However, the light emission intensity is not necessarily variable, and a specific light emission color is set by fixing the light emission intensity ratio. It can also be. In the configuration in which the emission color is fixed or variable within a specific range, a configuration in which two LEDs are combined to generate a light emission color, or a single LED and the color of the condenser lens 37 are combined to generate a light emission color. A configuration or the like can also be applied.
[0020]
In the front light 10 of the present embodiment having the above configuration, light incident on the light guide plate 12 from the light emitting element 15 via the bar light guide 13 is incident on the inner surface of the light guide plate 12 or the inner surface side of the cover member 18. The gentle slope portion contributes to light propagation, and the steep slope portion propagates in the direction from the light guide 13 side toward the light guide plate 12 side while repeating the effect of being reflected on the lower surface. Note that a reflective layer made of a metal thin film having excellent light reflectivity such as Al or Ag may be formed on the inner surface side of the cover member 18. If such a reflection layer is formed, the light incident on the cover member 18 from the inside of the light guide 13 or the light guide plate 12 is reflected without being attenuated and returned to the bar light guide 13 or the light guide plate 12 side. And the brightness of the front light 10 can be increased.
[0021]
A detailed configuration of the prism groove 14 formed in the reflection area 12c of the light guide plate 12 will be described with reference to FIG. As shown in FIG. 4, the prism groove 14 is composed of two slope portions formed to be inclined with respect to the reference surface of the reflection area 12c, and the slope portion having a relatively gentle inclination angle is a gentle slope surface. The portion 14a and the steep slope portion 14b formed with a steeper inclination angle than the gentle slope portion 14a. The gentle slope portions 14a and the steep slope portions 14b are alternately formed. The inclination angle θ1 of the gentle slope portion 14a shown in FIG. 4 is preferably 1 ° to 10 °, for example, and the inclination angle θ2 of the steep slope portion 14b is preferably 41 ° to 45 °, for example. By forming the prism grooves controlled within these ranges, a front light having a uniform amount of emitted light in the surface direction of the exit surface 12b can be obtained.
[0022]
When the inclination angle θ1 of the gentle slope portion 14a is less than 1 °, sufficient brightness as an illuminating device cannot be obtained, and when it exceeds 10 °, the uniformity of the amount of light emitted from the exit surface of the light guide plate is Since it falls, it is not preferable. Further, when the inclination angle θ2 of the steep slope portion is less than 41 ° or more than 45 °, the luminance of the lighting device decreases, which is not preferable. In addition, when a regular pattern exists in the object to be illuminated, it is possible to suppress occurrence of interference fringes in the object to be illuminated by appropriately changing the pitch P of the prism grooves 14.
[0023]
Further, in the front light 10 of the present embodiment, the emitted light quantity is made uniform by making the structure of the bar light guide 13 appropriate. The configuration of the bar light guide 13 will be described in detail below with reference to FIG. FIG. 5 is an enlarged partial plan view showing a part of the bar light guide 13 shown in FIG. 2, and a reflective film 19 is provided on the reflection surface 13b of the bar light guide. The reflection film 19 is a metal thin film made of Al, Ag, or the like, and prevents light propagating inside the bar light guide 13 from leaking to the outside from the reflection surface 13b, thereby increasing the amount of light incident on the light guide plate 12. It is provided to make it.
[0024]
A plurality of wedge-shaped grooves 16 are formed on the reflection surface 13b of the bar light guide 13 according to the present embodiment, and these grooves 16 are inclined with respect to the emission surface 13a of the bar light guide 13. The angle α formed by the two slope portions 16a and 16b is, for example, not less than 105 degrees and not more than 115 degrees. When the angle α is less than 105 degrees, the emitted light in the desired direction cannot be obtained, and as a result, the luminance decreases. If the angle α exceeds 115 degrees, the emitted light quantity distribution cannot be kept uniform. The angle α is more preferably 108 degrees or greater and 112 degrees or less. With such a range, the amount of light emitted toward the light guide plate 12 can be further increased, and the brightness of the front light 10 can be further increased.
[0025]
Next, an example in which the above-described front light 10 is used for speedometer illumination of a passenger car will be described with reference to FIGS. 6A and 6B. The front light 10 of the present embodiment is mounted in an instrument panel 41 that is mounted on a driver's seat of a passenger car. For example, a speedometer 42 is attached to the emission surface 12 b side of the front light 10. The upper surface of the front light 10 on the reflective area (reflective surface) 12 c side is covered with a cover glass 43 of the instrument panel 41. The reflection surface 13 b of the front light 10 is formed in a circle having the same size as the circular scale panel 42 a constituting the speedometer 42.
[0026]
The reflection area 12c is composed of two slope portions formed to be inclined with respect to the reference plane of the reflection area 12c. The slope portions having a relatively gentle inclination angle are a gentle slope portion 14a and a gentle slope portion 14a. The steep slope portion 14b is formed with a steeper inclination angle. In the reflection area 12c, gentle slope portions 14a and steep slope portions 14b are alternately formed. By forming the prism groove 14 composed of the gentle slope portion 14a and the steep slope portion 14b, a front light having a uniform amount of emitted light in the surface direction of the exit surface 12b can be obtained.
[0027]
When the light emitting element 15 of the front light 10 is turned on when the speedometer 42 is illuminated, such as during night driving, the light emitted from the light emitting element 15 is first introduced into the light guide 13 and reflected by the light guide 13. The light is reflected by the surface 13 b and the propagation direction thereof is changed, and the light is introduced into the light guide plate 12 from the incident surface 12 a of the light guide plate 12 disposed to face the light exit surface of the light guide plate 13. And the light which propagates the inside of the light-guide plate 12 is reflected in the reflective area 12c of the light-guide plate 12, the propagation direction is changed, and the light which illuminates the speedometer 42 from the output surface 12b of the light-guide plate 12 is emitted. Is done.
[0028]
Since the light guide plate 12 is formed in a circle having the same size as the circular scale panel 42a constituting the speedometer 42, only light corresponding to the range of the scale panel 42a out of the light propagating inside the light guide plate 12 is formed. Can change the propagation direction toward the exit surface 12b. As a result, illumination light that illuminates only a circular area of the same size as the scale panel 42a of the speedometer 42 is emitted from the emission surface 12b. The circular illumination light emitted from the emission surface 12b illuminates only the range of the scale panel 42a of the speedometer 42. The driver monitors the speedometer 42 from the cover glass 43 through the transparent reflecting surface 13b.
[0029]
Since the front light 10 brightly illuminates only the range of the scale panel 42a of the speedometer 42 and does not illuminate the periphery of the scale panel 42a, the speedometer 42 can be easily read with high contrast. Further, since the amount of light applied to the speedometer 42 can be increased by the effect of concentrating the illumination light only on the range of the scale panel 42a of the speedometer 42, a high-luminance display can be obtained. If display is performed while switching the color of the illumination light during operation, the decorativeness and functionality can be improved.
[0030]
As shown in FIG. 7, a plurality of reflection areas (reflection surfaces) 42 may be formed on the base surface 41 of the front light 40. Three reflecting areas (reflecting surfaces) 42 a, 42 b, 42 c are formed on the base surface 41 of the large light guide plate 43. The reflection area 42 is composed of two slope portions, and the slope portion having a relatively gentle slope angle is formed with a gentle slope portion 14a and a steep slope portion formed with a steeper slope angle than the gentle slope portion 14a. 14b. And in the reflective area 42, the gentle slope part 14a and the steep slope part 14b are formed alternately. By forming the prism groove 14 composed of the gentle slope portion 14a and the steep slope portion 14b, a front light having a uniform amount of emitted light can be obtained.
[0031]
The reflection areas (reflection surfaces) 42a, 42b, and 42c are, for example, circular shapes having sizes corresponding to a speedometer, a rotation speed meter, and a fuel meter that constitute an instrument panel of a passenger car, for example. When light is incident from the two light sources 44 and 44 toward the incident surfaces on both sides of the light guide plate 43, the light emission surface 45 of the light guide plate 43 has a circular shape corresponding to the size of the reflection areas 42a, 42b, and 42c. Illumination light is irradiated. If the front light 40 is arranged on the instrument panel of the passenger car, only the speedometer, the rotation speed meter, and the fuel meter are brightly illuminated. And it does not illuminate to the periphery and falls visibility. Each meter on the instrument panel can be read clearly even at night.
[0032]
Further, the front light itself may function as a scale plate of the meter. In the embodiment shown in FIG. 8, the indicator 64 of the meter 63 is attached to the cover glass 62 that covers the emission surface 61 side of the front light 60. A scale 65 of a meter 63 is attached to the emission surface 61 of the front light 60. An incident surface 67 is formed at the center of the reflection area (reflecting surface) 66 of the front light 60, and a light emitting element 68 as a light source is formed facing the incident surface 67. A prism 69 is formed at the center of the emission surface 61. The reflection area (reflection surface) 66 is composed of two slope portions, and a slope portion having a relatively gentle slope angle is formed with a gentle slope portion 14a and a steeper slope angle than the gentle slope portion 14a. The steep slope portion 14b is formed. By forming the prism groove 14 composed of the gentle slope portion 14a and the steep slope portion 14b, a front light having a uniform amount of emitted light can be obtained.
[0033]
According to the front light 60 having such a configuration, the light emitted from the light emitting element 68 can change the propagation direction toward the inclined surface 66 a of the reflection area 66 by the action of the prism 69. The light reflected by the reflection area 66 illuminates the pointer 64 of the meter 63 and causes the scale 65 of the meter 63 affixed to the emission surface 61 to rise. The observer can easily read the meter 63 from the scale 65 and the pointer 64 clearly displayed.
[0034]
The light source, for example, the light emitting element may be easily replaced. In the embodiment shown in FIG. 9, an incident surface 73 is formed at the center of the reflection area (reflective surface) 72 of the front light 70 disposed on the top of the meter 71. An element socket 75 is formed in the center of the cover glass 74 that covers the meter 71 and the front light 70. A light emitting element 76 is detachably attached to the element socket 75, and the light emitting element 76 faces the incident surface 73. The reflection area (reflection surface) 72 is composed of two slope portions, and a slope portion having a relatively gentle slope angle is formed with a gentle slope portion 14a and a steeper slope angle than the gentle slope portion 14a. The steep slope portion 14b is formed. By forming the prism groove 14 composed of the gentle slope portion 14a and the steep slope portion 14b, a front light having a uniform amount of emitted light can be obtained. According to such a configuration, the light emitting element 76 can be easily attached / detached and exchanged from the outside (viewing side) of the cover glass 74, which is useful for improving the maintainability.
[0035]
The light emitting element may be easily replaced using an optical fiber or a light guide pipe. In the embodiment shown in FIG. 10, an incident surface 82 is formed at the center of the reflective area (reflecting surface) 81 of the light 80, and the light guide pipe 83 extends from the incident surface 82 toward the mounting panel 85 of the meter 84. . The end surface of the light guide pipe 83 faces the light emitting element 87 that is detachably attached to the element socket 86. The reflection area (reflection surface) 81 is composed of two slope portions, and a slope portion having a relatively gentle slope angle is formed with a gentle slope portion 14a and a steeper slope angle than the gentle slope portion 14a. The steep slope portion 14b is formed. By forming the prism groove 14 composed of the gentle slope portion 14a and the steep slope portion 14b, a kind of backlight having a uniform amount of emitted light can be obtained. According to such a configuration, the light-emitting element 87 can be easily replaced from the outside of the mounting panel 85, which helps to improve the maintainability.
[0036]
You may make it the structure which can attach or detach a light source directly to a front light. In the embodiment shown in FIG. 11, the front light 90 is formed with a light source insertion portion 92 into which a light pipe 91 incorporating a light emitting element can be inserted and removed. The reflection area (reflection surface ) is composed of two slope portions, and a slope portion having a relatively gentle slope angle is formed with a gentle slope portion 14a and a steeper slope angle than the gentle slope portion 14a. The steep slope portion 14b. By forming the prism groove 14 composed of the gentle slope portion 14a and the steep slope portion 14b, a front light having a uniform amount of emitted light can be obtained. According to such a configuration, the light source can be easily exchanged, and it is useful for enhancing the maintainability, and the decorativeness and functionality of the object to be illuminated are enhanced by exchanging the light pipes 91 of various emission colors. You can also.
[0037]
【The invention's effect】
As described above in detail, according to the illumination device of the present invention, the illumination light emitted from the emission surface illuminates only the same range as the shape of the plurality of reflection areas. By illuminating only the multiple areas that actually require illumination by forming multiple reflective areas with a size smaller than the base surface and limiting the illumination range to the case where the reflective surface is formed on the entire base surface Is possible. By not irradiating illumination light around the area where illumination is necessary, the individual visibility of the illumination range corresponding to the plurality of reflection areas can be improved. Moreover, if the light of a light source is irradiated only to an illumination range, each illumination intensity of a some illumination range will be raised. It is possible to provide an illuminating device that can efficiently and uniformly irradiate illumination light only to a plurality of regions that need to be illuminated. Furthermore, a circular object to be illuminated in the illumination range by the emitted light, such as a meter or a dial, can be visually recognized from the base surface side through the plurality of reflection areas and a portion between them . Furthermore, according to the present invention, the emission direction can be made visible from the base surface side through the reflection area and the portion between them.
If the reflection area is formed in a circular shape, it is possible to illuminate only a plurality of circular areas that actually require illumination. By not irradiating illumination light around a circular area that needs to be illuminated, the individual visibility of the circular illumination area corresponding to a plurality of reflective areas is enhanced.
This reflection area can be a circle having a size corresponding to the meter of the instrument panel, for example. If light is incident from the light source toward the incident surface of the light guide plate, the reflection area is A circular illumination light equivalent to the size is irradiated, and only the meter is illuminated brightly. And it does not illuminate to the periphery and falls visibility. The meter on the instrument panel can be read clearly at night.
Further, according to the present invention, the bar light guide reflects the light emitted from the light emitting element and introduced into the inside thereof by the side surface forming the wedge-shaped groove, thereby changing the light propagation direction to the light guide plate side. In other words, light is applied to the incident surface of the light guide plate. The light introduced from the bar light guide into the light guide plate propagates inside the light guide unit, is reflected by the surfaces constituting the prism grooves formed in the reflection area, and the propagation direction of the light guide plate is changed. It can radiate | emit from the output surface.
[Brief description of the drawings]
FIG. 1 is a partial perspective view of a front light (illumination device) which is an embodiment of an illumination device of the present invention.
2 is an exploded perspective view of the front light shown in FIG. 1. FIG.
FIG. 3 is an enlarged perspective view showing a light emitting element provided in the front light.
FIG. 4 is a cross-sectional view showing a configuration of prism grooves formed in a reflection area (reflection surface) of a light guide plate.
FIG. 5 is an enlarged partial plan view showing a part of a bar light guide.
FIG. 6 is an explanatory view showing an embodiment in which the front light of the present invention is used for illumination of a meter.
FIG. 7 is a perspective view showing another embodiment of the front light of the present invention.
FIG. 8 is a cross-sectional view showing another embodiment of the front light of the present invention.
FIG. 9 is a cross-sectional view showing another embodiment of the front light of the present invention.
FIG. 10 is a cross-sectional view showing another embodiment of the front light of the present invention.
FIG. 11 is a perspective view showing another embodiment of the front light of the present invention.
[Explanation of symbols]
10 Front light (lighting device)
DESCRIPTION OF SYMBOLS 11 Light guide part 12 Light guide plate 12a Incident surface 12b Outgoing surface 12c
12d Basic surface 14 Prism groove (groove)
15 Light emitting element (light source)

Claims (8)

A base on which an incident surface for introducing light emitted from a light source, an exit surface for emitting the light, and a reflective area including a minute groove for reflecting the light introduced from the incident surface toward the exit surface are formed. A light guide plate comprising a surface, a light guide part for propagating light between the incident surface and the output surface, and a plurality of light sources for introducing light into the incident surface of the light guide plate, the reflection area comprising: A plurality of areas are formed on the foundation surface with an area smaller than the area of the foundation surface, and a portion between the reflection areas in the light guide plate is formed into a flat plate shape, and each light source passes through the plurality of reflection areas. An illuminating device that is freely illuminable and that allows the direction of the emitted light to be visually recognized from the base surface side through the plurality of reflection areas and portions between them . The lighting device according to claim 1, wherein the reflection area is formed in a circular shape. The lighting device according to claim 1, wherein the reflection area is formed at a central portion of the base surface. The lighting device according to any one of claims 1 to 3, wherein the reflection area includes a plurality of prism grooves formed by alternately forming gentle slope portions and steep slope portions. 5. The illumination device according to claim 1, wherein the reflection area has a light transmission property that allows light incident at a constant angle to pass therethrough. A bar light guide in contact with the incident surface is provided outside the incident surface of the light guide plate, a light emitting element is disposed at an end of the bar light guide, and one side surface of the bar light guide is The side surface of the bar light guide opposite to the incident surface and opposite to the incident surface is formed as a reflective surface in which a plurality of wedge-shaped grooves are formed. 5. The lighting device according to any one of 4. The lighting device according to claim 1, wherein the light source is detachably attached to the light guide plate. The lighting device according to claim 7, wherein the light source can be attached and detached from the viewing side.

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