JP2014120319A - Illumination apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination apparatus capable of suppressing damage, deformations, and the like even if a light source and the incident surface of a light guide plate are positioned with respect to each other with high accuracy.SOLUTION: Even if a light guide plate 1 expands by a temperature change or a humidity change, a distance between an incident surface 13 and a substrate 21, that is, an LED 2 is made constant by compressive deformation of rubber 16. Therefore, it is possible to ensure stable illumination characteristics without damaging or deforming the LED 2 or the light guide plate 1.

Description

  The present invention relates to an illuminating device, for example, an illuminating device suitable for use in an illuminating device used for space production such as a house or a store.

  Conventionally, light sources arranged linearly or linearly are arranged on the end face of the plate-shaped light guide plate, the light of the light source is incident on the light guide plate from the incident surface that is the end face, and the light guide plate is guided. A light extraction means is provided on one of the two surfaces adjacent to and opposite to the incident end face, and light that is guided through the light guide plate by this light extraction means is gradually emitted to the outside, and as a result, planar light emission is performed. Sidelight type lighting devices are known. Sidelight type lighting devices using this light guide plate have been widely used as backlights for liquid crystal monitors.

  Patent Document 1 discloses a backlight that reflects light emitted from a lamp by a reflecting mirror having a parabolic cross section, guides the light into a light guide plate, and emits light in a planar manner with light guided through the light guide plate. Has been. There is an attempt to use such a backlight as a lighting device. If the backlight of Patent Document 1 can be diverted to a lighting device, a thin lighting device with excellent design can be provided.

JP 2007-304304

  Here, as one problem when diverting the backlight of Patent Document 1 to a lighting device, there is a problem that it is desired to set the distance from the light source to the incident surface of the light guide plate with high accuracy. There is also an idea that the light source and the light guide plate may be fixed to the housing for such a problem. However, in order to form the light guide plate at low cost, it should be molded with a resin such as acrylic. However, when the resin expands due to environmental temperature or humidity, the distance from the light source is reduced or the light guide plate is warped. There is a possibility that a malfunction occurs and proper lighting cannot be performed.

  Furthermore, in recent years, along with improvement in luminous efficiency and increase in the amount of emitted light, lighting devices using LEDs (Light Emitting Diodes) that are considered to be environmentally friendly with long life and low power consumption are being put into practical use. is there. When such an LED is used in a lighting device, it has a Lambertian emission characteristic, so in order to capture a higher amount of light, it is necessary to reduce the distance between the LED and the incident surface as much as possible. When the light guide plate expands, the risk of causing damage to the LEDs increases.

  The present invention has been made in view of the above circumstances, and in order to perform good illumination, even when the light source and the incident surface of the light guide plate are positioned with high accuracy, the illumination device can suppress damage, deformation, and the like. The purpose is to provide.

The lighting device according to claim 1 is a lighting device disposed between at least a pair of side walls,
A light source installed on one of the pair of side walls;
An incident surface on which light emitted from the light source is incident, a first main surface that emits light incident from the incident surface, and a second main surface that is opposed to the first main surface and forms an optical path deflecting unit. A light guide plate having,
A positioning member for relatively positioning the light source and the incident surface;
It has an elastic body arrange | positioned between the opposing surface which opposes the said incident surface, and the other of said pair of side walls.

  According to the present invention, the light incident plate and the light source can be brought as close as possible (including the case of contact) by the positioning member. On the other hand, when the light guide plate expands or contracts due to a temperature change or a humidity change. By deforming the elastic body, the influence can be absorbed and the distance between the incident surface and the light source can be kept constant, so that a load is applied to the light source and the light guide plate with a simple configuration. It is possible to realize a lighting device that can always exhibit high lighting performance. Note that “a pair of side walls” means, for example, a case where holes are formed in the structure itself and a pair of side walls is provided, or an inner wall of an opening provided in a housing installed in the structure is used as a pair of side walls. Including. The “elastic body” includes all elastic materials such as rubber, springs and leaf springs.

  The lighting device according to claim 2 is characterized in that, in the invention according to claim 1, a reflective surface is provided on the facing surface.

  By providing a reflecting surface on the facing surface, light that is incident from the incident surface and linearly guided is reflected and returned by the reflecting surface, so that a more efficient lighting device can be provided. Note that “providing a reflecting surface on the facing surface” means that a reflecting tape is applied to the facing surface or a casing in the vicinity thereof, or a reflecting film is deposited on the facing surface itself. The reflection surface may be a reflection diffusion surface.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, the incident surface is two adjacent side surfaces of the light guide plate, and the two light sources respectively face the side surfaces. It is characterized by being arranged.

  When the two light sources are arranged opposite to the adjacent side surfaces, the opposing surfaces are often adjacent to each other, thereby making the opposing surfaces easy to be reflective surfaces. Further, since the light sources are close to each other, the wiring and the like can be shortened, and the wiring is excellent.

  According to a fourth aspect of the present invention, in the invention according to the third aspect, the light source includes a plurality of LED chips.

  By using the LED chip, it is possible to realize an illumination device with high energy efficiency and high efficiency and high uniformity.

  According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the optical path deflecting unit is formed of a plurality of diffusion dots, and the density of the diffusion dots on the second main surface is at least the It changes according to the distance from a light source, It is characterized by the above-mentioned.

  Since the amount of light guided through the light guide plate decreases with increasing distance from the light source, assuming that the density of the diffusing dots on the second main surface is the same, as the distance from the light source increases, the first The amount of light emitted from the main surface is reduced. Therefore, by changing the density of the diffusing dots on the second main surface according to at least the distance from the light source, a high amount of illumination light can be emitted even from the first main surface far from the light source. become.

  According to a sixth aspect of the present invention, in the invention of the fifth aspect, when the pitches of the LED chips of the light source are equal, an intersection of the two incident surfaces is defined as an origin in a plane including the second main surface. When the x-axis is taken along one incident surface and the y-axis is taken along the other incident surface, the radius r (mm) of the circular diffused dot is expressed by equation (1). It is characterized by that.

  When the pitches of the LED chips of the light sources are equal, by satisfying the expression (1), illumination light with uniform illuminance can be emitted regardless of the position of the first main surface.

  According to a seventh aspect of the present invention, in the invention of the fifth aspect, in the plane including the second main surface, the intersection of the two incident surfaces is an origin, and the x-axis along one incident surface When the y-axis is taken along the other incident surface, the radius of the diffused dot is circular when the pitch of the LED chip in the light source becomes finer as it goes away from the origin according to equation (3) r (mm) is represented by the formula (2).

  When the pitch of the LED chips in the light source is finer as the distance from the origin increases according to the equation (3), the illumination light having a uniform illuminance is satisfied regardless of the position of the first main surface by satisfying the equation (2). Can be emitted.

  The illumination device according to an eighth aspect is the invention according to the first or second aspect, wherein the incident surface is one side surface of the light guide plate, and the light source is disposed to face the side surface. It is characterized by that.

  Thereby, the number of parts can be reduced and a simple lighting device can be obtained.

  According to a ninth aspect of the present invention, in the invention of the seventh aspect, the light source includes a plurality of LED chips.

  By using the LED chip, it is possible to realize an illumination device with high energy efficiency and high efficiency and high uniformity.

  According to a tenth aspect of the present invention, in the invention according to the eighth or ninth aspect, the optical path deflecting means is a plurality of diffusion dots whose density increases as the distance from the light source increases.

  By using such diffusing dots, an arbitrary pattern can be arranged on the second main surface, and a uniform illumination device can be realized on the exit surface even if the light sources are discretely arranged. For example, since the amount of light emitted from the first main surface decreases as the distance from the incident surface increases, illumination light with uniform illuminance can be emitted if the density is increased accordingly.

  The illumination device according to claim 11 is characterized in that, in the invention according to any one of claims 1 to 10, the incident surface has a V-groove shape.

  By adjusting the angle of the V-groove shape, light incident from the incident surface can be easily guided efficiently using total reflection, and can be emitted with high efficiency.

  The illuminating device according to a twelfth aspect is the invention according to any one of the first to eleventh aspects, wherein a reflection diffusing member is provided facing the surface of the light guide plate other than the first main surface and the incident surface. It is characterized by that.

  After entering from the incident surface, the light emitted from other than the first main surface is returned to the light guide plate again by the reflection diffusing member and reused, so that the emission efficiency can be increased. In particular, when two light sources are arranged opposite to the adjacent side surfaces of the light guide plate, it becomes easy to install a reflection diffusion member on the opposite surface side, and the illumination efficiency is improved. Note that a reflection / diffusion member may be provided in a portion where the emitted light cannot be used as illumination light even on the first main surface.

  According to a thirteenth aspect of the present invention, in the invention according to any one of the first to twelfth aspects, a diffusing member is arranged to face the first main surface.

  By making the illumination light pass through the diffusion member, it is possible to reduce illuminance unevenness generated on the first main surface and to reduce glare of the emitted light.

  A lighting device according to a fourteenth aspect is characterized in that, in the invention according to any one of the first to thirteenth aspects, the light guide plate has a square plate shape.

  Thereby, the illuminating device which is easy to manufacture can be provided. In particular, when two light sources are provided, the light source can have the same shape, and the manufacturing cost can be reduced.

  According to the present invention, it is possible to provide an illuminating device that can suppress breakage, deformation, and the like even when the light source and the incident surface of the light guide plate are positioned with high accuracy in order to perform good illumination.

It is a perpendicular direction sectional view of lighting installation 10 concerning a 1st embodiment. It is the figure which cut | disconnected the structure of FIG. 1 by the II-II line | wire, and looked at the arrow direction. It is a figure which expands and shows the site | part shown by the arrow III of FIG. It is a figure which expands and shows the 2nd main surface. It is sectional drawing which shows only a light source and a light-guide plate. It is sectional drawing similar to FIG. 2 which shows the modification of this Embodiment. It is sectional drawing similar to FIG. 1 which shows the modification of this Embodiment. It is sectional drawing similar to FIG. 1 which shows the modification of this Embodiment. It is sectional drawing of the planar illuminating device concerning 2nd Embodiment. It is an enlarged view of the entrance plane concerning a modification. It is sectional drawing which shows the modification of a positioning member. It is vertical direction sectional drawing of the illuminating device 10 used as the model of an Example. It is the figure which cut | disconnected the structure of FIG. 12 by the XIII-XIII line | wire, and looked at the arrow direction. It is a figure which shows the light emission characteristic of Lambertian by an angle and light intensity. In the first embodiment, in the plane including the second main surface 12, the intersection point of the two incident surfaces 13 is the origin O, the x-axis is taken along one incident surface 13, and the y along the other incident surface 13 is y. It is a figure which takes an axis | shaft and shows. FIG. 6 is a diagram showing a luminance ratio distribution of Example 1. In the second embodiment, in the plane including the second main surface 12, the intersection of the two incident surfaces 13 is set as the origin O, the x-axis is taken along one incident surface 13, and the y along the other incident surface 13 is y. It is a figure which takes an axis | shaft and shows. It is a figure which shows the luminance ratio distribution of Example 2. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. Moreover, the same code | symbol is used about the same structural member, and detailed description is abbreviate | omitted suitably.

(First embodiment)
FIG. 1 is a vertical sectional view of the lighting device 10. FIG. 2 is a view of the configuration of FIG. 1 taken along the line II-II and viewed in the direction of the arrow. The illuminating device according to the present invention is an illuminating device 10 having an irradiation surface that emits surface light. For example, the illuminating device is preferably attached to an indoor ceiling CL and used as indoor illumination. As shown in FIG. 1, the lighting device 10 includes a first main surface 11 that emits light and a second main surface 12 that faces the first main surface and extends substantially in parallel to the second main surface 12. A plurality of light emitting elements that extend in a direction intersecting the optical plate 1 and the first main surface 11 and the second main surface 12 and are opposed to one side surface portion that becomes the incident surface 13 of the light guide plate 1. 2, the light emitted from the light emitting element 2 is guided into the light guide plate 1 and emitted from the first main surface 11.

  The light guide plate 1 has a flat plate shape as shown in FIG. 1 and is configured to be integrally accommodated in a case (housing) 3 together with the light emitting element 2 so that the first main surface 11 is exposed. Below the case 3, a lower plate 32 having a rectangular opening 31 is attached to support the light guide plate 1.

  The light emitting element 2 may be a light source that emits illumination light in the direction of the incident surface 13. For example, a linear light source (cold cathode tube) or a plurality of light sources arranged at intervals in the longitudinal direction of the incident surface 13 may be used. A point light source (LED) can be used. Further, it is preferable to use an LED that emits white light with low power consumption and high emission intensity. Therefore, in the present embodiment, a white LED is used. Here, instead of the light emitting element 2, the LED 2 will be described below. A plurality of LEDs 2 are linearly arranged at substantially equal intervals (for example, a pitch of about 15 mm) in the longitudinal direction (direction perpendicular to the paper surface) of the substrate 21 attached to the inner side wall 3a of the case 3. The LED 2 and the substrate 21 constitute a light source.

  The LED 2 is a white LED, and emits white light by combining a blue LED and a phosphor (for example, a yellow phosphor) that is excited by light from the blue LED and emits excitation light having a predetermined wavelength. The white LED may be a high color rendering LED that is a combination of a red LED, a blue LED, and a green LED. By using the high color rendering LED, it is possible to realize an illumination device suitable for an application requiring high color reproducibility.

  For example, the substrate 21 has a length approximately equal to the entire width in the longitudinal direction of the incident surface 13, and a plurality of chip-type LEDs 2 are mounted on the substrate 21 at a predetermined pitch. Thus, although the board | substrate 21 is united in the longitudinal direction, it is good also as a structure which divides | segments into several board | substrates and each is electrically connected. The board 21 is connected to a power supply circuit (not shown) arranged outside the lighting device by wiring, and the brightness of the lighting device can be adjusted by adjusting the current flowing through the LEDs with a brightness adjustment button provided in the electric circuit. The emission color can be adjusted.

  In the present embodiment, as shown in FIG. 2, the incident surface 13 is the two adjacent side surfaces of the light guide plate 1, and the substrates 21 to which the LEDs 2 are attached are arranged facing the respective incident surfaces 13. Has been. Therefore, the wiring 22 for supplying power to one of the substrates 21 only needs to connect the adjacent ends of the two substrates 21, thereby facilitating the wiring. A screw member 30 as a positioning member is provided between the substrate 21 and the incident surface 13.

  FIG. 3 is an enlarged view of a portion indicated by an arrow III in FIG. As shown in FIG. 3, in the screw member 30, the screw portion 30 a is screwed into the screw hole 21 a formed in the surface of the substrate 21, and the head portion 30 b is brought into contact with the incident surface 13. By adjusting the screwing amount of the screw portion 30a engaged with the screw hole 21a, the distance Δ between the end surface of the head portion 30b, that is, the incident surface 13 and the substrate 21 can be adjusted. The screw member 30 is fixed to the case 3 by passing the screw portion 30a of the screw member 30 through the screw hole 21a and screwing it into another screw hole formed on the side surface of the case 3. It can also function as a member.

  As shown in FIGS. 1 and 2, a reflective tape 15 is affixed to an opposing surface 14 opposite to the incident surface 13. Thereby, the light guided to the opposing surface 14 in the light guide plate 1 is reflected by the reflective tape 15 and guided in the reverse direction.

  Between each facing surface 14 and the side wall 3b facing the side wall 3a of the case 3, two block-like rubbers 16 are arranged (adhered or the like) as elastic bodies. In the assembled state, the rubber 16 is compressively deformed, and the light guide plate 1 is pressed toward the screw member 30 by its elastic force. When the reflection diffusion tape is not stretched on the facing surface 14 of the light guide plate 1, the light emitted from the facing surface 14 of the light guide plate 1 is returned into the light guide plate 1 by making the surface of the rubber 16 white. Increases functionality. As the rubber 16, in the case of black rubber, for example, the product name PORON (registered trademark) H series of Roger Sinoac Co., Ltd. can be used, and in the case of white rubber, reflective type synthetic rubber, or black rubber + reflective A diffusion sheet (for example, Kimoto Co., Ltd. product name Ref White (registered trademark), Toray Industries, Inc. product name Lumirror (registered trademark)) or the like can be used.

FIG. 4 is an enlarged view showing the second main surface 12. On the second main surface 12, as an optical path deflecting means, for example, diffusion dots 12a are provided by printing or the like. Specifically, titanium oxide (TiO ₂ ), calcium carbonate (CaCo ₃ ), various pigment-based inks. Or dots made of resin fine particles. However, a film (sheet) on which similar diffusion dots are printed may be affixed to the second main surface 12, or the concave portions may be created in a dot shape by a stamper, laser processing, or the like.

  On the second main surface 12, the density of the diffusion dots 12a is adjusted according to the amount of light guided. For example, since the amount of guided light decreases as the distance from the incident surface 13 increases, it is preferable that the density of the diffusing dots 12a increase as the distance from the LED 2 increases because the illuminance distribution of the emitted light can be made uniform. . Increasing the density includes both reducing the pitch with a constant area and increasing the printing radius with a constant pitch. Both may be performed simultaneously.

  The distribution of the diffusing dots 12a varies depending on the size of the light guide plate 1 and the like. That is, in the present embodiment, the area A (upper right in FIG. 2) farthest away from the point O closest to the intersection of the LEDs 2 on the second main surface 12 has the highest density of the diffusion dots 12a. Become. As the distance from the LED 2 increases, the amount of light emitted from the first main surface 11 also decreases. Therefore, by increasing the density of the diffusion dots 12a, it is possible to ensure the illuminance uniformity of the entire first main surface 11. Further, the pitch p1 of the LEDs 2 may be reduced as the distance from the point O increases.

  FIG. 5 is a cross-sectional view showing only the light source and the light guide plate. The operation of the present embodiment will be described with reference to FIG. Light emitted from the LED 2 and incident from the incident surface 13 of the light guide plate 1 is guided through the light guide plate 1 while being totally reflected. The light reaching the facing surface 14 is reflected here and guided in the opposite direction. In the middle of light guide, the light incident on the diffusion dots 12a diffuses in various directions. The light diffused downward by the diffusing dots 12a is directed to the opposite lower surface (first main surface 11), and the light satisfying the total reflection condition continues to be guided in the light guide plate 1, but from the total reflection condition The detached light is emitted from the first main surface 11 to the outside and becomes illumination light. On the other hand, the light diffused upward by the diffusing dots 12 a is emitted from the second main surface 12, is reflected inside the upper case 3, enters the light guide plate 1 again, and is transmitted through the first main surface 11. And then injected outside.

  According to the present embodiment, even when the light guide plate 1 expands due to temperature change or humidity change, the rubber 16 is compressed and deformed, so that the distance between the incident surface 13 and the substrate 21, that is, the LED 2 becomes constant. Stable lighting characteristics can be secured without causing damage or deformation of the LED 2 or the light guide plate 1.

  FIG. 6 is a cross-sectional view similar to FIG. 2 showing a modification of the present embodiment. In this modification, the pitch p3 of the LEDs 2 on both the substrates 21 is arranged so as to become finer as the distance from the origin, which is the intersection of the two incident surfaces 13, according to the equation (3), so that the illuminance distribution of the emitted light Can be made uniform. In such a case, it is preferable that the radius r (mm) of the circular diffusion dot (see FIG. 4) is expressed by equation (2).

  FIG. 7 is a cross-sectional view similar to FIG. 1 showing a modification of the present embodiment. In this modification, a reflection diffusion sheet (reflection diffusion member) 33 is attached to the entire inner surface of the case 3. Here, the reflection diffusion sheet 33 is also opposed to a portion of the first main surface 11 that does not affect illumination (here, a portion facing the lower plate 32). A diffusion plate (diffusion member) 34 is attached to the lower surface of the lower plate 32 of the case 3. Only one of the reflection diffusion sheet 33 and the diffusion plate 34 may be provided. As the reflective diffusion sheet 33, for example, Lef White made by Kimoto Co. can be used. Registered trademark) and the product name Aromabright (registered trademark) of Nippon Polyester Co., Ltd. can be used.

  When the light emitted from the LED 2 is incident from the incident surface 13 and is not emitted from the first main surface 11 but is emitted from another surface, if this is left unattended, the efficiency is lowered. Therefore, the light emitted from other than the first main surface 11 is reflected and diffused by the reflection diffusion sheet 33, and is returned again into the light guide plate 1 to be reused, thereby increasing the emission efficiency. However, if the incident surface 13 is covered with the reflective diffusion sheet 33, the incident light is blocked, so that the incident surface 13 is not covered with the reflective diffusion sheet 33. Further, the light emitted from the first main surface 11 is transmitted through the diffusion member 34, thereby reducing unevenness in illuminance generated on the first main surface 11 and reducing the glare of the emitted light.

  FIG. 8 is a cross-sectional view similar to FIG. 1 showing another modification. In this modification, the diffusion plate 34 is disposed between the lower plate 32 of the case 3 and the light guide plate 1. However, it is desirable to provide a reflection diffusion sheet 33 on the diffusion plate 34 except for the opening 31 of the lower plate 32.

(Second Embodiment)
FIG. 9 is a view similar to FIG. 2 according to the second embodiment, but the diffusion dots are exaggerated. In the present embodiment, the light guide plate 1 has one incident surface 13 and one light source (the LED 2 and the substrate 21) opposed to the incident surface 13 as compared to the above-described embodiment. In the present embodiment, the pitch p2 of the diffusing dots 12a provided on the second main surface 12 is formed so as to decrease (that is, the density increases) as the distance from the LED 2 increases. However, the pitches in the alignment direction of the LEDs 2 are equal.

  As the distance from the LED 2 is increased (toward the right in FIG. 9), the amount of light emitted from the first main surface 11 is also reduced. Therefore, by increasing the density of the diffusion dots 12a, the illuminance of the entire first main surface 11 is uniform. Can be secured. Other configurations are the same as those of the above-described embodiment.

  In the above embodiment, the incident surface 13 is a flat surface, but may be a V-shaped groove as shown in FIG. In FIG. 10, the incident surface 13 has a V-shaped groove 13c in which an upper incident surface 13a and a lower incident surface 13b intersect each other at an angle θ. In particular, a part of the light beam emitted from the LED 2 is refracted by entering the upper incident surface 13a, and enters the second main surface 12 at a deep incident angle, thereby easily satisfying the total reflection condition. Become. On the other hand, a part of the light beam emitted from the LED 2 is refracted by entering the lower incident surface 13b, and enters the first main surface 11 side at a deep incident angle, thereby easily satisfying the total reflection condition. Become. That is, by providing the V-shaped groove 13c on the incident surface 13, the light guide efficiency can be further increased. The inclination angle α of the upper incident surface 13a with respect to the vertical surface and the inclination angle β of the lower incident surface 13b with respect to the vertical surface can be arbitrarily adjusted.

  FIG. 11 is a cross-sectional view showing a modification of the positioning member. A positioning member 30 shown in FIG. 11A includes a screw member 31 having a screw part 31 a and a head part 31 b and an annular member 32 fixed to the screw part of the screw member 31. The annular member 32 has a recess 32a and a hole 32b into which the shaft portion of the screw member 31 is fitted and fixed. When the screw portion 31a of the screw member 31 is engaged with the hole 32b, the head portion 32b of the screw member 31 is housed in the recess 32a. The screw member 31 is attached to the substrate 21 by screwing the screw portion 31a of the screw member 31 into the screw hole 21a of the substrate 21 shown in FIG. 3. At this time, the end surface of the annular member 31 is the incident surface of the light guide plate 1. Positioning can be carried out by abutting on 13.

  In the modification shown in FIG. 11B, the protrusion 3 b is formed so as to protrude from the lower surface of the upper plate of the case 3, and can be positioned by contacting a part of the incident surface 13 of the light guide plate 1. ing. 11C, one side surface 33a of the member 33 having a U-shaped cross section is fixed to the side surface 3a of the case 3, and the other side surface 33b is fixed to the incident surface 13 of the light guide plate 1. In the modification shown in FIG. Positioning can be performed by contacting the part.

Example 1
Examples of the present invention will be described below. The model of an Example is shown to FIG. The same bonds as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. The light guide plate 1 has a size of 275 mm in length and width and a thickness t = 4 mm, and the distance between the LED 2 as a light source and the incident surface of the light guide plate 1 is 0.2 mm. The LEDs 2 are arranged on the substrate 21 at an equal pitch. The positioning member 30 between the light source and the incident surface 13 uses a screw member (not shown) that fixes the substrate 21 and the case 3 so that the distance between the LED 2 and the incident surface 13 facing the LED 2 can be determined. It can be selected freely within the range of length, and the distance can be kept constant. An elastic body 16, for example, a highly reflective white rubber is installed on the opposite surface 14 opposite to the incident surface 13 (in the case where a reflective diffusion tape is directly attached to the opposite surface 14, a simple rubber may be used). On the second main surface 12 side, a highly diffusive and highly reflective diffuser plate 33, for example, a reflex white manufactured by Kimoto Co., Ltd. is installed. Similarly, a highly diffusive and highly reflective reflective diffusion tape 15 is applied to the facing surface 14 side.

A diffusion dot 12a (see FIG. 4) is printed on the surface of the second main surface 12 as an optical path deflecting unit. Examples of the diffusing dots 12a include titanium oxide (TiO ₂ ), calcium carbonate (CaCo ₃ ), various pigment-based inks, or resin fine particles. When the diffusion dot 12a is completely diffused, the distribution of the diffused light reflected from the light incident on the diffusion dot 12a has a so-called Lambertian emission characteristic as shown in FIG. The illumination light to be emitted has almost Lambertian characteristics.

  Here, as shown in FIG. 15, in the plane including the second main surface 12, the intersection of the two incident surfaces 13 is the origin O, the x-axis is taken along one incident surface 13, and the other incident surface Take the y-axis along 13. According to the examination result of the present inventor, when the LEDs 2 are arranged at equal intervals (equal pitch), the first principal surface 11 is changed by greatly changing the radius of the diffusing dots 12a as the distance from the origin O increases. It has been found that the illuminance of the illumination light emitted from the lamp approaches uniform. At this time, the diffusing dots 12a are printed in line symmetry with respect to the dotted line at a pitch of 1 mm in both xy directions, but the radius r (mm) of the circular diffusing dots 12a is expressed by the equation (1). .

  In FIG. 16, the vertical axis is a value (luminance ratio) when the luminance peak value is 1, and the horizontal axis is the distance from the origin O, which is on the diagonal line of the light guide plate 1 indicated by the dotted line in FIG. It is the graph which plotted the value in a position (up to 384 mm). According to FIG. 16, in the case of Example 1, the luminance ratio can be suppressed within 30%. However, if the distance from the origin O is more than 250 mm, the luminance is suddenly decreased, and a sense of incongruity is expected, and it is desirable to make the luminance more uniform depending on the application.

(Example 2)
As described above, in the second embodiment, the pitch P (mm) of the LEDs 2 arranged in the y-axis direction becomes finer as the distance from the origin O increases according to the equation (3), and in the second embodiment, as shown in FIG. The pitch P (mm) of the LEDs 2 arranged in the axial direction is made finer as the distance from the origin O increases according to the equation (3). The diffusion dots 12a are printed in line symmetry with respect to the dotted line at a pitch of 1 mm in both xy directions, and the radius r (mm) of the circular diffusion dot 12a is expressed by equation (2).

  FIG. 18 is a graph showing the relationship between the luminance ratio and the distance in Example 2. Compared to Example 1, the luminance ratio is approximately 80% or more within a range of 350 mm, there is no sharp drop in luminance except in the vicinity of both ends, and there is little possibility of giving a sense of incongruity. Further, the optical efficiency (total luminous flux from the exit surface / total luminous flux of the light source) is improved by 6% compared to the first embodiment. In this way, high-performance lighting can be realized by optical design including LED pitch or the intensity of each LED so as to satisfy the predetermined optical performance. Note that the density can be adjusted by changing the pitch of the diffusion dots instead of changing the radius of the diffusivity dots.

  The present invention is not limited to the embodiments described in the specification, and other embodiments and modifications are apparent to those skilled in the art from the embodiments and ideas described in the present specification. It is.

1 Light Guide Plate 2 Light Emitting Element (LED)
3 Case 10 Illuminating device 11 First main surface 12 Second main surface 12a Diffusing dots 13 Incident surface 13a Upper incident surface 13b Lower incident surface 13c V-shaped groove 14 Opposing surface 15 Reflective tape 16 Rubber 21 Substrate 21a Hole 22 Wiring 30 Screw member 30a Screw part 30b Head 31 Rectangular opening 32 Lower plate 33 Reflection diffusion sheet 34 Diffusion plate CL Ceiling

Claims (14)

A lighting device disposed between at least a pair of side walls,
A light source installed on one of the pair of side walls;
An incident surface on which light emitted from the light source is incident, a first main surface that emits light incident from the incident surface, and a second main surface that is opposed to the first main surface and forms an optical path deflecting unit. A light guide plate having,
A positioning member for relatively positioning the light source and the incident surface;
An illuminating device comprising: an opposing surface facing the incident surface; and an elastic body disposed between the other of the pair of side walls. The lighting device according to claim 1, wherein a reflective surface is provided on the facing surface.   The illumination device according to claim 1, wherein the incident surface is two adjacent side surfaces of the light guide plate, and the two light sources are respectively disposed to face the side surfaces.   The lighting device according to claim 3, wherein the light source includes a plurality of LED chips.   The said optical path deflection | deviation means is formed from the several diffusion dot, The density of the said diffusion dot in a said 2nd main surface changes according to the distance from the said light source at least. Lighting equipment. When the pitches of the LED chips of the light source are equal, the intersection of the two incident surfaces is the origin, the x-axis is taken along one incident surface, and the other incident surface is formed on the plane including the second main surface. The illumination device according to claim 5, wherein a radius r (mm) of the circular diffusing dot when the y axis is taken along is expressed by the formula (1).

In the plane including the second main surface, when the intersection of the two incident surfaces is an origin, the x-axis is taken along one incident surface, and the y-axis is taken along the other incident surface, the light source In the case where the pitch of the LED chip in FIG. 4 is finer as the distance from the origin increases according to the equation (3), the radius r (mm) of the circular diffusion dot is expressed by the equation (2). The lighting device according to claim 5.

  The lighting device according to claim 1, wherein the incident surface is one side surface of the light guide plate, and the light source is disposed to face the side surface.   The lighting device according to claim 8, wherein the light source includes a plurality of LED chips arranged at equal intervals.   The illumination device according to claim 8 or 9, wherein the optical path deflecting unit is a plurality of diffusion dots whose density increases as the distance from the light source increases.   The lighting device according to claim 1, wherein the incident surface has a V-groove shape.   The lighting device according to claim 1, wherein a reflection diffusion member is provided opposite to the first main surface and the incident surface of the light guide plate.   The illuminating device according to any one of claims 1 to 12, wherein a diffusing member is disposed to face the first main surface.   The lighting device according to claim 1, wherein the light guide plate has a square plate shape.

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