JP2017204367A - Planar illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a visual effect.SOLUTION: A planar illumination device includes an optical member and a light source part. The optical member has a base formed like a flat plate. The light source part is arranged along a side face of the base of the optical member. In the brightness distribution, in the base, of light incoming from a light source part, a boundary between a bright area and a dark area is inclined with respect to a line orthogonal to the side face.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a planar lighting device.

  2. Description of the Related Art Conventionally, planar illumination devices used for automobile high-mount stoplights and the like have been provided. In such a planar illumination device, for example, a light source, a mirror, and a lens may be used for light distribution control.

  In order to enhance the visual effect, the optical member is formed so that stereoscopic display using the parallax of both eyes with respect to light emitted from two points on the exit surface of the observer observing the light exit surface is possible. Technology is known.

JP-A-2015-87769

  However, in the above-described conventional technology, since the parallax of the observer's eyes is used, for example, the stereoscopic display may not be performed depending on the position of the observer, and for example, when the observer observes the emission surface with one eye It is not displayed in 3D. That is, the conventional planar lighting device has room for improvement in terms of enhancing the visual effect.

  This invention is made | formed in view of the above, Comprising: It aims at providing the planar illuminating device which can improve a visual effect.

  In order to solve the above-described problems and achieve the object, a planar illumination device according to one aspect of the present invention includes an optical member having a base formed in a flat plate shape, and a side surface of the base of the optical member. In the luminance distribution in the base portion of the light incident from the light source portion, the boundary between the bright portion and the dark portion is inclined with respect to a line orthogonal to the side surface.

  According to one embodiment of the present invention, the visual effect can be enhanced.

FIG. 1 is a front view showing a planar illumination device according to the embodiment. FIG. 2 is a side view showing the planar illumination device according to the embodiment. FIG. 3 is a side sectional view showing the prism portion according to the embodiment. FIG. 4 is a side sectional view showing an optical member having a low reflection portion and a luminance suppression portion according to the embodiment. FIG. 5 is a diagram illustrating an illumination mode of the planar illumination device according to the embodiment. FIG. 6 is a diagram illustrating a luminance distribution on the light extraction surface according to the embodiment. FIG. 7 is a front view showing the planar illumination device according to the first modification. FIG. 8 is a side view showing the planar illumination device according to the first modification. FIG. 9 is a front view illustrating another example of the planar lighting device according to the first modification. FIG. 10 is a diagram illustrating a luminance distribution on the light extraction surface according to the first modification. FIG. 11 is a front view showing a planar illumination device according to the second modification. FIG. 12 is a diagram illustrating a luminance distribution on the light extraction surface according to the second modification. FIG. 13 is a front view showing a planar illumination device according to Modification 3-1. FIG. 14 is a diagram illustrating a luminance distribution on the light extraction surface according to Modification 3-1. FIG. 15 is a front view illustrating a planar illumination device according to Modification 3-2. FIG. 16 is a diagram illustrating a luminance distribution on the light extraction surface according to Modification 3-2. FIG. 17 is a front view showing a planar illumination device according to Modification 3-3. FIG. 18 is a diagram illustrating a luminance distribution on the light extraction surface according to Modification 3-3.

  Hereinafter, a planar illumination device according to an embodiment will be described with reference to the drawings. Note that the application of the planar lighting device is not limited by the embodiment described below. It should be noted that the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual situation. Even between the drawings, there are cases in which portions having different dimensional relationships and ratios are included.

(Embodiment)
First, the outline | summary of a structure of the planar illuminating device 1 is demonstrated using FIG.1 and FIG.2. FIG. 1 is a front view showing a planar illumination device according to the embodiment. In FIG. 1, the luminance distribution of light emitted from the light source unit in a state of focusing on the side surface of the base part is schematically shown as a waveform on the left side of the planar illumination device 1. FIG. 2 is a side view showing the planar illumination device according to the embodiment.

  As shown in FIG. 1, the planar illumination device 1 includes an optical member 2 and a light source unit 3.

  The optical member 2 has a base 20 that is a transparent body formed in a flat plate shape. For example, the base portion 20 is formed of a light transmissive material. For example, the base 20 may be formed of acrylic resin, polycarbonate, or the like. For example, the base 20 may be a so-called light guide plate. Note that the base 20 may be formed of any material as long as it has desired strength, heat resistance, and the like. Further, in the optical member 2, one surface 21 (hereinafter also referred to as “light extraction surface 21”) illustrated in FIG. 1 is a light emitting surface.

  As shown in FIG. 2, the base portion 20 of the optical member 2 is formed with a prism portion 22 on one side in the thickness direction of the base portion 20. For example, the prism portion 22 is formed on the back surface (hereinafter also referred to as “back surface”) of the light extraction surface 21 of the optical member 2. The prism portions 22 are formed side by side in a predetermined direction. For example, the prism portion 22 is formed side by side in the longitudinal direction of the base portion 20 (left-right direction in FIG. 2).

  Here, the prism portion 22 will be described with reference to FIG. FIG. 3 is a side sectional view showing the prism portion according to the embodiment. The prism portion 22 is formed in a shape having a predetermined prism function. In the prism portion 22, a second region 222 having a prism shape is continuous with a first region 221 having a predetermined inclination angle θ <b> 1 with respect to a plane in which the thickness direction of the base portion 20 is orthogonal in a cross section along the longitudinal direction of the base portion 20. In the following description, the first region 221 of one prism portion 22 continues to the height of the first region 221 of one prism portion 22, that is, the second region 222 of another prism portion 22. The height of the position is defined as “first height”. In addition, the height of the position where the first region 221 and the second region 222 of one prism portion 22 are continuous is referred to as a “second height”.

  The prism portion 22 may be formed along the width direction of the base portion 20 (hereinafter, also referred to as “short direction”), or may be formed inclined with respect to the short direction of the base portion 20. . For example, the first region 221 of the prism portion 22 may be formed along the short direction of the base portion 20. Further, for example, the second region 222 of the prism portion 22 may be formed along the short direction of the base portion 20. In the example shown in FIG. 3, the light extraction surface 21 is a flat surface and the thickness direction of the base portion 20 is perpendicular to the surface. Therefore, the surface where the thickness direction of the base portion 20 is orthogonal will be described as the light extraction surface 21 hereinafter. .

  For example, in the prism portion 22, as shown in FIG. 3, in the first region 221 whose inclination angle θ <b> 1 with respect to the light extraction surface 21 is, for example, not less than 0 degrees (°) and not more than 8 degrees in the cross section along the longitudinal direction of the base portion 20. The second region 222 having a prism shape is continuous. Further, as shown in FIG. 3, the second region 222 of one prism portion 22 is continuous with the first region 221 of another prism portion 22.

  As shown in FIG. 3, in the cross section along the longitudinal direction of the base portion 20, the first region 221 of one prism portion 22 has a second height higher than the first height from the first height in the thickness direction of the base portion 20. It has a shape that extends to the height. The second region 222 of one prism portion 22 has a shape in which one end portion is continuous with the first region 221 at the second height and extends to the first height, and the other end at the first height. The portion is continuous with the first region 221 of the other prism portion 22. For example, the second region 222 of the leftmost prism portion 22 in FIG. 3 is continuous with the first region 221 of the adjacent (right) prism portion 22. In addition, the inclination angle with respect to the light extraction surface 21 of the second region 222 in the cross section along the longitudinal direction of the base 20 may be appropriately set according to a desired light distribution.

  In the prism portion 22, the ratio R11 of the first region 221 in the length of the base portion 20 in the longitudinal direction is, for example, 60% or more and less than 100%. As shown in FIG. 3, the length L11 of the first region 221 in the length in the longitudinal direction of the base 20 is the length L10 of the entire prism portion 22 in the length in the longitudinal direction of the base 20 (hereinafter referred to as “structural unit length”). R11 ”) is, for example, 60% or more and less than 100%. For example, the ratio R11 described above is calculated by the following mathematical formula (1).

  Ratio R11 = length L11 of first region 221 / constituent unit length L10 (1)

  For example, the structural unit length L10 corresponds to the total length of the first region 221 and the second region 222 in the length of the base 20 in the longitudinal direction.

  The prism unit 22 is formed such that the structural unit length L10 of the prism unit 22 is, for example, 40 μm or more and 500 μm or less. With the configuration described above, the optical member 2 is transparent at the base portion 20 on which the prism portion 22 is formed. For example, the optical member 2 is transparent, and when the light source unit 3 is in a non-lighting state, the back surface side can be seen through from the light extraction surface 21 side of the base 20, and the light extraction surface 21 side from the back surface side of the base 20. Can be seen through.

  Further, as shown in FIG. 2, for example, a prism region (for example, a prism portion 22) to be subjected to prism processing is formed on the back surface of the light extraction surface 21 of the optical member 2. For example, the prism region is formed by arranging prism structures in the longitudinal direction of the base 20. In addition, non-prism regions (hereinafter also referred to as “non-prism portions 23”) that are not subjected to prism processing are formed at both ends in the longitudinal direction of the base portion 20. Note that the length of the non-prism region may be appropriately set according to the use of the planar illumination device 1 or the like.

  Further, in order to form the prism region (prism portion 22) and the non-prism region (non-prism portion 23), for example, the optical member 2 is subjected to predetermined processing on the back surface of the base portion 20 by post-processing as a processing method for performing prism processing. A prism region in which prism processing is performed may be formed in this region. Further, for example, in the optical member 2, after the prism processing is performed over the entire back surface of the base portion 20, the non-prism region is formed by removing the prism processing in the region corresponding to the non-prism region by post-processing. May be. Further, for example, in the optical member 2, the region facing the non-prism region on the back surface of the base 20 is formed lower than the height of the region subjected to the prism processing, and then the prism region is formed by post-processing. A prism region may be formed. By forming the prism region and the non-prism region by such a processing method, the optical member 2 is formed with a prism region in which a prism processing is performed on a predetermined region on the back surface of the base 20 and is not formed on the other regions. A prism region is formed.

  The processing method for forming the prism region and the non-prism region is not limited to the above example, and any processing method can be used as long as the prism region or the non-prism region can be formed in a desired region. Also good. Further, for example, the optical member 2 may be molded by the above processing method using a predetermined mold.

  Note that the plurality of prism portions 22 may be formed symmetrically with respect to a center line passing through a central portion in the longitudinal direction on the back surface of the light extraction surface 21 of the optical member 2. A plurality of prism portions 22 are arranged in the order of the first region 221 and the second region 222 from the side surface 24 on the left side in FIG. 2 to the central portion in the longitudinal direction. Further, for example, on the back surface of the light extraction surface 21 of the optical member 2, the prism portion 22 arranged in the order of the first region 221 and the second region 222 from the right side surface 25 side in FIG. Multiple lines. As described above, the plurality of prism portions 22 may be formed mirror-symmetrically with respect to the center line in the longitudinal direction on the back surface of the light extraction surface 21 of the optical member 2.

  Moreover, the optical member 2 of the planar illumination device 1 may have various configurations in order to perform desired light distribution control. This point will be described with reference to FIG. FIG. 4 is a side view showing an optical member having a low reflection portion and a luminance suppression portion according to the embodiment. As shown in FIG. 4, the optical member 2 may include a low reflection portion 26 and a luminance suppression portion 27.

  As shown in FIG. 4, a low reflection portion 26 that suppresses reflection into the base 20 is provided on the light extraction surface 21 side of the base 20 in the optical member 2. For example, the optical member 2 is formed with a low reflection portion 26 having a low reflection function so as to overlap the light extraction surface 21. For example, the low reflection portion 26 may have a fine uneven shape of 1 μm or less such as a dielectric multilayer film formed by sputtering or vapor deposition or a moth-eye shape. For example, the low reflection part 26 may be formed by performing the low reflection process on the light extraction surface 21. For example, in the low reflection process, it is preferable to process the light extraction surface 21 into a mirror surface state. For example, the above-described processing methods include direct processing (sputtering, vapor deposition, shaping, etc.) on the base 20 as a light guide plate, insert molding of a low reflection film, and application of a low reflection film via an adhesive or adhesive. Any processing method such as combination may be used.

  Note that the regular reflectance of the light extraction surface 21 is, for example, 1.6% or less. For example, when the regular reflectance of the light extraction surface 21 is 1.6% or less, in the example illustrated in FIG. 4, the ratio of the light beam IL14 reflected in the base 20 out of the light beams IL12 toward the light extraction surface 21 is 1. .. 6% (= light amount of IL14 / light amount of IL12 * 100) or less. Further, for example, the regular reflectance of the light extraction surface 21 may be 1.6% or less by forming the low reflection portion 26 so as to overlap the light extraction surface 21 of the optical member 2.

  In addition, formation of the low reflection part 26 mentioned above is an example, and the optical member 2 may be any configuration as long as the regular reflectance of the light extraction surface 21 satisfies a desired value. For example, if the regular reflectance of the light extraction surface 21 satisfies a desired value, the optical member 2 may not have the low reflection portion 26.

  As shown in FIG. 4, a luminance suppression unit 27 that suppresses light emission to the back surface side is provided on the back surface side of the base 20 in the optical member 2. For example, the optical member 2 is formed with a luminance suppressing portion 27 that suppresses light emission to the back surface side so as to cover the back surface. For example, the luminance suppression unit 27 may be a louver film, a film that reflects the wavelength of light from a light source (dielectric multilayer film), a film that absorbs light (dielectric multilayer film), a transparent film containing a dye-based pigment, or the like. Good. For example, a louver film is preferably used to shield light emitted in an oblique direction. The luminance suppressing unit 27 may have any configuration as long as it has a desired function.

  A luminance ratio LR1 that is a ratio of the luminance of the light extraction surface 21 to the luminance of the back surface is, for example, 20 or more. For example, the luminance ratio LR1 is calculated by the following mathematical formula (2).

  Luminance ratio LR1 = luminance of light extraction surface 21 / luminance of back surface (2)

  For example, the luminance ratio LR1 may be 20 or more by arranging the luminance suppressing unit 27 on the back side of the base 20. For example, the luminance of the light extraction surface 21 is the luminance in the vertical direction of the light extraction surface 21 and the luminance in the thickness direction of the base 20 of the back surface of the light extraction surface 21 (surface on which the prism portion 22 is formed). Also good. For example, the luminance ratio LR1 may be a ratio of the front luminance on the light extraction surface 21 side to the front luminance on the back surface side.

  The arrangement of the luminance suppressing unit 27 described above is an example, and the optical member 2 may have any configuration as long as the luminance ratio LR1 satisfies a desired value. For example, if the luminance ratio LR1 satisfies a desired value, the optical member 2 may not have the luminance suppression unit 27.

  Here, the light distribution in the optical member 2 will be described using the light beams IL11 to IL15 shown in FIG. Light rays IL11 to IL15 shown in FIG. 4 virtually indicate the light distribution in the optical member 2. For example, among the light beams IL11 that travel from the base 20 toward the second region 222, some of the light beams IL12 are reflected in the direction of the light extraction surface 21 by the second region 222 having a prism function.

  A part of the light beam IL <b> 13 from the base 20 toward the light extraction surface 21 is emitted outside the light extraction surface 21. For example, since the regular reflectance of the light extraction surface 21 satisfies a desired value due to the reflection being suppressed by the low reflection portion 26, most of the light rays IL13 are radiated out of the light extraction surface 21. The Thus, the planar illumination device 1 can suppress an increase in the amount of light reflected from the light extraction surface 21 side into the base 20 when the regular reflectance of the light extraction surface 21 satisfies a desired value. The light extraction efficiency can be improved.

  In addition, a part of the light beam IL <b> 14 from the base 20 toward the light extraction surface 21 is reflected by the light extraction surface 21. For example, since reflection is suppressed by the low reflection portion 26, a small amount of light IL 14 out of the light IL 12 is reflected by the light extraction surface 21. As described above, the optical member 2 is able to reduce the light leaking from the back surface by suppressing reflection on the light emitting surface (light extraction surface 21).

  In addition, for example, among the light beams IL <b> 11 that travel from the base 20 toward the second region 222, some of the light beams IL <b> 15 pass through the second region 222 and are emitted outside the base 20. That is, the light beam IL15 becomes light that leaks in an oblique direction from the back surface when it is virtually planar. Such light leaking from the back surface may be visually recognized by a person on the back surface side, for example, a person inside or outside the vehicle in which the planar lighting device 1 is used as a high-mount light. However, in the planar lighting device 1, since the luminance ratio LR1 satisfies a desired value by the luminance suppression unit 27 and the like, light leaking to the back side is suppressed, and the influence on the person on the back side can be suppressed. .

  As shown in FIG. 1, the light source unit 3 includes a holding member 30 and a light source 31 that is, for example, an LED (Light Emitting Diode). The light source unit 3 is disposed along a pair of side surfaces 24 and 25 of the base 20 of the optical member 2. A pair of light sources 3 is provided at both ends of the optical member 2. In addition, the light source part 3 may be provided in only one of the both end parts of the optical member 2.

  For example, the pair of holding members 30 holds the optical member 2 from both sides. In FIG. 1, a pair of light sources 3 is provided at both ends of the optical member 2 in the longitudinal direction of the base 20 and holds the optical member 2. Each holding member 30 holds the light source 31 at both ends of the optical member 2. Although FIG. 1 illustrates a state in which the light source 31 is exposed in a front view, the light source 31 may be covered with, for example, the holding member 30 as long as the light source 31 is disposed at a predetermined position with respect to the optical member 2. . The optical member 2 may be held by the holding member 30 by covering the vicinity of the side surfaces 24 and 25 with the holding member 30.

  Each light source unit 3 may be provided close to the side surfaces 24 and 25 of the base 20, or may be provided apart from the side surfaces 24 and 25 of the base 20. Each light source unit 3 is provided with a plurality (four in FIG. 1) of light sources 31. The plurality of light sources 31 are arranged along the side surfaces 24 and 25 of the base 20. The plurality of light sources 31 are discretely arranged, for example, arranged at equal intervals. Thereby, the some light source 31 can be used as a point light source, respectively.

  As shown in FIG. 1, the light emitted from the plurality of light sources 31 has a non-uniform luminance distribution having bright and dark portions on the side surfaces 24 and 25 of the base portion 20 (in FIG. 1, the luminance on the left side surface 24). Only the distribution is shown). Thereby, the light of the non-uniform brightness distribution which has a bright part and a dark part can be radiated | emitted from the light extraction surface 21 of the base 20. FIG. Further, in FIG. 1, in the waveform indicating the luminance distribution on the side surface 24 of the base portion 20, the peak side (right side in the figure) is a bright part of luminance, and the valley side (left side in the figure) is a dark part of luminance. For example, the luminance distribution of light emitted from the plurality of light sources 31 increases as the distance from the center of each light source 31 increases, and decreases as the light source 31 and the light source 31 move away from each other.

  Here, the non-uniform brightness means, for example, a brightness ratio between a bright part and a dark part (dark part brightness / brightness) when measured in a state where the light incident end face (side surfaces 24, 25) of the base 20 is focused. Part luminance) is, for example, at least 80% or less, preferably 50% or less. As a result, in the planar illumination device 1, light with a nonuniform luminance distribution having a bright portion and a dark portion is incident on the side surfaces 24 and 25 of the optical member 2, so that the bright light is emitted from the light extraction surface 21 of the base portion 20. It is possible to emit light having a non-uniform luminance distribution having a part and a dark part. In the example illustrated in FIGS. 1 and 2, light having a luminance distribution in which bright portions and dark portions are alternately arranged on the side surfaces 24 and 25 of the optical member 2 is incident and emitted from the light extraction surface 21. Is a luminance distribution in which bright portions and dark portions are alternately arranged along the longitudinal direction of the base portion 20.

  The thickness of the plurality of light sources 31 may be approximately the same as the thickness of the base portion 20. In addition, the width W10 of the base 20 may be wider than the overall width W11 in the arrangement direction of the plurality of light sources 31, or is equal to the entire width W11 in the arrangement direction of the plurality of light sources 31, or of the plurality of light sources 31. It may be narrower than the overall width W11 in the arrangement direction.

  Further, for example, in the front luminance of the light emitting area (light extraction surface 21), that is, the luminance in the vertical direction of the light extraction surface 21, the luminance distribution is focused on the light incident end surfaces (side surfaces 24 and 25) of the light guide plate (base portion 20). In the combined state, the luminance distribution (averaged in the thickness direction) is calculated at a pitch of at least 1 mm, preferably 0.5 mm, in the width direction (short direction) of the light guide plate.

  Here, the illumination aspect in the lighting state of the planar illumination device 1 will be described with reference to FIG. FIG. 5 is a diagram illustrating an illumination mode of the planar illumination device according to the embodiment. In addition, in FIG. 5, the case where the planar illuminating device 1 is seen from diagonally upward in the front is shown. FIG. 5 shows an actual measurement result of the lighting state of the planar lighting device 1. Moreover, the illumination aspect shown in FIG. 5 is an example, and the illumination aspect of the planar illumination device 1 is not limited to this.

  In the non-lighting state of the planar illumination device 1, for example, it is transparent over the base 20 of the optical member 2. As shown in FIG. 5, in the lighting state of the planar illumination device 1, light is emitted from the light extraction surface 21, that is, the prism region (prism portion 22) subjected to the prism processing, and outside the light extraction surface 21 (in FIG. 5). The non-prism area (non-prism portion 23) on the left and right outer sides of the light extraction surface 21 that is not subjected to prism processing does not emit light. As shown in FIG. 5, the illumination mode of the planar lighting device 1 in the lighting state is that the prism region, that is, the light extraction surface 21 emits light, and the longitudinal direction of the base portion 20 from each side edge of the emitted light extraction surface 21. A plurality of light rays extending toward the center are visually recognized. A plurality of light rays are visually recognized side by side along each side edge of the light extraction surface 21. The plurality of light beams are viewed with a similar inclination with respect to a line orthogonal to the side surfaces 24 and 25 of the base 20. In addition, the line orthogonal to the side surfaces 24 and 25 of the base part 20 respond | corresponds to the line of the longitudinal direction of the base part 20 in the example of FIG.

  The light source unit 3 and the viewpoint are connected via the prism unit 22 between each light source unit 3 provided along the side surfaces 24 and 25 of the base unit 20 and the viewpoint of the person viewing the light emitting surface (light extraction surface 21). Light can be perceived at the position. As a result, the light / dark boundary is inclined according to the position of the viewpoint of the person viewing the light extraction surface 21, and a plurality of inclined light rays are perceived in the light emission surface to the person who has viewed the emitted light extraction surface 21. A plurality of inclined light beams can perceive a feeling of depth that extends from the front to the back of the light-emitting surface, thereby enhancing the visual effect.

  Note that the inclination angles of the plurality of light rays vary depending on the position of the viewpoint of the person viewing the light emitting surface. In the example shown in FIG. 5, light rays extending from both side edges of the light extraction surface 21 intersect in the vicinity of the center in the longitudinal direction of the base 20, and the intersection of the light rays depends on the position of the viewpoint of the person viewing the light emitting surface. It moves in the direction along the longitudinal direction of 20. In addition, the plurality of light rays are portions having higher brightness than other portions on the light extraction surface 21, and the light rays are visually recognized in the example illustrated in FIG. There may be. Further, the optical member 2 may be processed or the light emitted from the light source unit 3 may be adjusted in order to make the light rays visible in various modes.

  Next, the luminance distribution on the light extraction surface 21 will be described with reference to FIG. FIG. 6 is a diagram illustrating a luminance distribution on the light extraction surface according to the embodiment. In addition, in FIG. 6, the case where the planar illuminating device 1 is seen from diagonally upward in the front is shown. Moreover, in FIG. 6, the simulation result of the lighting state of the planar illuminating device 1 is shown. Moreover, the luminance distribution 4 shown in FIG. 6 is an example, and the aspect of the luminance distribution 4 is not limited to this.

  As shown in FIG. 6, the luminance distribution 4 in the vertical direction of the light extraction surface 21 that is a light emitting area has a bright portion 40 and a dark portion 41 of luminance. Thus, since the luminance distribution 4 on the light extraction surface 21 has the bright part 40 and the dark part 41, the luminance is not uniform. That is, the luminance distribution 4 on the light extraction surface 21 has nonuniform luminance. As shown in FIG. 6, in the luminance distribution 4 on the light extraction surface 21, a plurality of bright portions 40 extend from both side edges of the light extraction surface 21 toward the longitudinal center of the base 20 in the dark portion 41 on one surface. . In the luminance distribution 4 on the light extraction surface 21, the bright portions 40 and the dark portions 41 are alternately arranged in a direction orthogonal to the side surfaces 24 and 25 of the base portion 20. The boundary between the bright part 40 and the dark part 41 is similarly inclined with respect to a line orthogonal to the side surfaces 24 and 25 of the base part 20. In addition, the line orthogonal to the side surfaces 24 and 25 of the base part 20 respond | corresponds to the line of the longitudinal direction of the base part 20 in the example of FIG.

  As described above, the boundary between the bright part 40 and the dark part 41 is inclined, so that a pictorial depth feeling (perspective) that extends from the front to the back on the light extraction surface 21 can be produced. Thereby, the person who has seen the light emitting surface (light extraction surface 21) can perceive the boundary between the inclined bright part 40 and the dark part 41, and the light is emitted by the boundary between the inclined bright part 40 and the dark part 41. The surface can be perceived as having a depth that extends from the front to the back. Thereby, for example, the visual effect can be enhanced with a configuration that does not use binocular parallax.

  Note that the inclination angle of the boundary between the bright part 40 and the dark part 41 in the luminance distribution 4 varies depending on the position of the viewpoint of the person viewing the light emitting surface. Further, in the example shown in FIG. 6, the boundary between the bright part 40 and the dark part 41 extending from both side edges of the light extraction surface 21 intersects in the vicinity of the center in the longitudinal direction of the base part 20. It moves in a direction along the longitudinal direction of the base 20 according to the position of the viewpoint.

  A planar illumination device according to a modification of the embodiment will be described with reference to the drawings. In addition, about the structure similar to above-described embodiment, the code | symbol similar to embodiment is attached | subjected and description may be abbreviate | omitted.

(Modification 1)
First, a planar lighting device 1A according to the first modification will be described with reference to FIGS. 7, 8, 9 and 10. FIG. FIG. 7 is a front view showing the planar illumination device according to the first modification. FIG. 8 is a side view showing the planar illumination device according to the first modification. FIG. 9 is a front view illustrating another example of the planar lighting device according to the first modification. FIG. 10 is a diagram illustrating a luminance distribution on the light extraction surface according to the first modification. In addition, in FIG. 10, the case where 1 A of planar illumination apparatuses are seen from diagonally upward in the front is shown. Moreover, in FIG. 10, the simulation result of the lighting state of 1 A of planar illumination apparatuses is shown. Moreover, the luminance distribution 4A shown in FIG. 10 is an example, and the aspect of the luminance distribution 4A is not limited to this.

  As shown in FIG. 7, the planar illumination device 1A includes an optical member 2A and a light source unit 3A. The optical member 2A has a base portion 20A that is a transparent body formed in a flat plate shape. Also in the optical member 2A, one surface 21A shown in FIG. 7 (hereinafter, also referred to as “light extraction surface 21A”) is a light emitting surface. The optical member 2A is different from the optical member 2 of the above-described embodiment in that it includes an absorption surface 50A or a scattering surface 51A described later. About another point, it is the same as that of the optical member 2 of above-described embodiment.

  An absorption surface 50A that absorbs light incident on the base 20A or a scattering surface 51A that scatters light incident on the base 20A is formed on a surface orthogonal to the side surfaces 24A and 25B of the base 20A. That is, the surface orthogonal to the side surfaces 24A and 25A of the base 20A is the absorption surface 50A or the scattering surface 51A. In the case of the absorption surface 50A, for example, the absorption surface 50A may be formed by applying black coating to the surfaces orthogonal to the side surfaces 24A and 25A of the base 20A, or surfaces orthogonal to the side surfaces 24A and 25A of the base 20A. A black form may be applied to the absorbent surface 50A. In the case of the scattering surface 51A, for example, minute unevenness may be formed on the surface orthogonal to the side surfaces 24A and 25A of the base portion 20 to form the scattering surface 51A.

  Further, for example, either one of the surfaces orthogonal to the side surfaces 24A and 25A of the base 20A may be the absorption surface 50A and the other may be the scattering surface 51A. Further, for example, only one of the surfaces orthogonal to the side surfaces 24A and 25A of the base 20A may be used as the absorption surface 50A or the scattering surface 51A. The absorbing surface 50A and the scattering surface 51A may have any configuration as long as they have a desired absorption rate.

  As shown in FIG. 7, the light source unit 3 </ b> A includes a holding member 30 </ b> A, a light source 31, and a light incident element 32. Unlike the light source unit 3 of the above-described embodiment, the light source unit 3A in Modification 1 emits light so as to have a uniform luminance distribution on the side surface 24A (and side surface 25A) of the base 20A. In the first modification, the light source unit 3A is disposed along the pair of side surfaces 24A and 25A of the base 20A of the optical member 2A. A pair of light sources 3A is provided at both ends of the optical member 2A. Note that the light source unit 3A may be provided on only one of both end portions of the optical member 2A.

  For example, the pair of holding members 30A holds the optical member 2A from both sides. In FIG. 7, a pair of light source units 3A is provided at both ends of the optical member 2A in the longitudinal direction of the base 20A, and holds the optical member 2A. Each holding member 30A holds the light source 31 at both ends of the optical member 2A. 7 illustrates a state in which the light source 31 is exposed in a front view, but the light source 31 may be covered with, for example, the holding member 30A as long as the light source 31 is disposed at a predetermined position with respect to the optical member 2A. . The optical member 2A may be held by the holding member 30A by covering the vicinity of the side surfaces 24A and 25A with the holding member 30A.

  Each light source unit 3A is provided with a light source 31 at a position sandwiching the light incident element 32 from the longitudinal direction of the light incident element 32 (vertical direction in FIG. 7). For example, the two light sources 31 are arranged so that light enters the light incident element 32 from the side end portions of the light incident element 32. Note that only one light source 31 may be used as long as the desired light distribution control is performed. The light source 31 allows light to enter the light incident element 32 from one of the side end portions of the light incident element 32. You may arrange | position so that it may light.

  For example, the light incident element 32 has a function of converting light emitted from the light source 31 that is a point light source into light of a linear light source. For example, the light incident element 32 is formed of a light transmissive material. The light incident element 32 may be a so-called light bar. The light incident element 32 is provided with one surface intersecting the longitudinal direction facing the optical member 2A. The light incident element 32 is provided so that one surface thereof faces the side surfaces 24A and 25A of the base portion 20A. For example, in the light source section 3A on the left side in FIG. 7, the light incident element 32 is provided along the side surface 24A of the base section 20A. Further, in the light source unit 3A on the left side in FIG. 7, the light incident element 32 is provided with one surface facing the side surface 24A of the base 20A. For example, in the light source unit 3A on the right side in FIG. 7, the light incident element 32 is provided along the side surface 25A of the base unit 20A. Further, in the light source unit 3A on the right side in FIG. 7, the light incident element 32 is provided with one surface facing the side surface 25A of the base 20A.

  In addition, a mechanism that performs predetermined optical control is provided on a surface 321 (hereinafter, also referred to as “reflecting surface 321”) opposite to the surfaces facing the side surfaces 24A and 25A in the light incident element 32. For example, the reflection surface 321 of the light incident element 32 has a function of controlling the light distribution of light incident from the side end of the light incident element 32 in the direction of the optical member 2A. For example, the reflecting surface 321 of the light incident element 32 may include a portion having a roughening process to form minute irregularities and having a light scattering function and a portion not having a roughening process. Further, for example, a prism may be disposed on the reflection surface 321 of the light incident element 32. The reflection surface 321 of the light incident element 32 may have any configuration as long as light incident from the side end of the light incident element 32 can be distributed in the direction of the optical member 2A. The width of the light incident element 32 is desirably equal to or greater than the width of the base portion 20A in the short direction. Thereby, in the planar illumination device 1A, the light from the light incident element 32 is irradiated over the entire lateral direction of the side surfaces 24A and 25A of the optical member 2A, so that the light extraction surface 21A of the base portion 20A is more evenly distributed. Can emit light.

  As shown in FIG. 9, a predetermined light distribution member is provided on the surface of the light incident element 32 that faces the side surfaces 24 </ b> A and 25 </ b> A of the base 20 </ b> A, that is, the opposite surface 322 of the reflective surface 321 of the light incident element 32. May be. For example, a lenticular lens, a diffusing element, a prism, or a TIR-Fresnel lens may be provided as a light distribution member on the surface of the light incident element 32 that faces the side surfaces 24A and 25A of the base 20A. The light incident element 32 may be continuous with the side surfaces 24A and 25A of the base portion 20A. For example, the light incident element 32 may be integrally formed with the base 20A.

  In addition, it is desirable that the width W12 of the region where the luminance is uniform in the light incident element 32 is equal to or greater than the width W10 in the short direction of the base portion 20A. Here, “uniform brightness” means, for example, that the brightness ratio between the bright part and the dark part (dark part brightness / bright part brightness) is 70% or more, preferably 80% or more. Thereby, 1 A of planar illumination apparatuses are irradiated with the light from the light incident element 32 over the whole lateral direction of the side surfaces 24A and 25A of the optical member 2A. The light incident element 32 may have the same thickness as the base 20A. In the example shown in FIG. 7, for the sake of simplicity, the case where the width W12 of the region where the luminance is uniform in the light incident element 32 is the same as the width of the light incident element 32 is illustrated. The width W12 of the region where the luminance is uniform in the element 32 may be narrower than the width of the light incident element 32.

  For example, in the front luminance of the light emitting area (light extraction surface 21A), that is, the luminance in the vertical direction of the light extraction surface 21A, the luminance distribution is focused on the light incident end surfaces (side surfaces 24A and 25A) of the light guide plate (base portion 20A). In the state, the luminance distribution (averaged in the thickness direction) is calculated at a pitch of at least 1 mm, preferably 0.5 mm, in the width direction (short direction) of the light guide plate. Further, for example, by setting the width W12 of the region where the luminance is uniform in the light incident element 32 to be equal to or larger than the width W10 in the short direction of the base portion 20A, the bright portion and the dark portion of the luminance obtained by the calculation method described above are used. The luminance ratio (dark portion luminance / bright portion luminance) can be 70% or more, preferably 80% or more.

  Moreover, the surface orthogonal to the side surfaces 24A and 25B of the base portion 20A is the absorption surface 50A or the scattering surface 51A. Thereby, 1 A of planar illumination apparatuses can radiate | emit the light of the uneven brightness distribution which has a bright part and a dark part from 21 A of light extraction surfaces of 20 A of bases. In the example shown in FIGS. 7 and 8, light having a more uniform luminance distribution is incident on the side surfaces 24A and 25A of the optical member 2A than in the case of only the point light source, and the light is absorbed by the absorbing surface 50A. Or the light is scattered by the scattering surface 51A. Thereby, the light radiated | emitted from 21 A of light extraction surfaces can be made into the luminance distribution in which the bright part and dark part of a brightness | luminance were located in a line along the longitudinal direction of 20 A of bases.

  When the surface orthogonal to the side surfaces 24A and 25B of the base 20A is the absorption surface 50A, the light absorption rate at the absorption surface 50A is at least 0.05, preferably 0.1 or more, and more preferably 0. .3 or more. As a result, the planar illumination device 1A has a light portion and a dark portion from the light extraction surface 21A of the base portion 20A even when light with a more uniform luminance distribution is incident on the side surfaces 24A and 25A of the optical member 2A. It is possible to emit light having a uniform desired luminance distribution.

  As shown in FIG. 10, the luminance distribution 4A in the vertical direction of the light extraction surface 21A, which is a light emitting area in the base 20A, has a bright portion 40A and a dark portion 41A. By absorbing or scattering light on the side surfaces 24A and 25A of the base portion 20A, the light reflection component is reduced and the dark portion 41A is generated. As described above, in the luminance distribution 4A on the light extraction surface 21A, for example, when the light extraction surface 21A is viewed from an oblique direction, a dark part is visually recognized, and the luminance looks uneven. As shown in FIG. 10, the luminance distribution 4A on the light extraction surface 21A has a dark part 41A near the absorption surface 50A or the scattering surface 51A (see FIGS. 7 and 9). The dark part 41A extends toward the center of the lateral direction of the side surfaces 24A and 25A as the distance from the light source part 3A in the longitudinal direction of the base part 20A increases. That is, in the luminance distribution 4A on the light extraction surface 21A, the bright portion 40A and the dark portion 41A of the luminance are arranged in a direction orthogonal to the side surfaces 24A and 25A of the base portion 20A. The boundary between the bright portion 40A and the dark portion 41A is inclined with respect to a line orthogonal to the side surfaces 24A and 25A of the base portion 20A. Note that the lines orthogonal to the side surfaces 24A and 25A of the base 20A correspond to the longitudinal lines of the base 20A in the examples of FIGS.

  As described above, the boundary between the bright part 40A and the dark part 41A is inclined, so that it is possible to bring out a pictorial depth feeling (perspective) that extends from the front to the back on the light extraction surface 21A. Thereby, the person who has seen the emitted light emitting surface (light extraction surface 21A) can perceive the boundary between the inclined bright part 40A and the dark part 41A, and light is emitted by the boundary between the inclined bright part 40A and the dark part 41A. The surface can be perceived as having a depth that extends from the front to the back. Thereby, for example, the visual effect can be enhanced with a configuration that does not use binocular parallax.

  Note that the inclination angle of the boundary between the bright part 40A and the dark part 41A in the luminance distribution 4A varies depending on the position of the viewpoint of the person viewing the light emitting surface. In the example shown in FIG. 10, the boundary between the bright portion 40A and the dark portion 41A extending from both side edges of the light extraction surface 21A intersects in the vicinity of the center in the longitudinal direction of the base portion 20A. It moves in a direction along the longitudinal direction of the base 20A according to the position.

(Modification 2)
Next, a planar lighting device 1B according to Modification 2 will be described with reference to FIGS. FIG. 11 is a front view showing a planar illumination device according to the second modification. FIG. 12 is a diagram illustrating a luminance distribution on the light extraction surface according to the second modification. In addition, in FIG. 12, the case where the planar illuminating device 1B is seen from diagonally upward in the front is shown. Moreover, in FIG. 12, the simulation result of the lighting state of the planar illuminating device 1B is shown. Moreover, the luminance distribution 4B shown in FIG. 12 is an example, and the aspect of the luminance distribution 4B is not limited to this. The planar illumination device 1B is different from the planar illumination device 1A in that the holding member 30B includes the absorption surface 50B or the scattering surface 51B. Since the other points are the same as those of the planar lighting device 1A of the first modification, “** A” of the planar lighting device 1A is read as “** B”.

  As shown in FIG. 11, the planar illumination device 1B includes an optical member 2B and a light source unit 3B. The optical member 2B has a base 20B that is a transparent body formed in a flat plate shape. Also in the optical member 2B, one surface 21B shown in FIG. 11 (hereinafter, also referred to as “light extraction surface 21B”) is a light emitting surface. The optical member 2B is the same as the optical member 2 of the above-described embodiment.

  As illustrated in FIG. 11, the light source unit 3 </ b> B includes a holding member 30 </ b> B, a light source 31, and a light incident element 32. Also in the second modification, unlike the light source unit 3 of the above-described embodiment, the light source unit 3B emits light so as to have a uniform luminance distribution on the side surface 24B (and the side surface 25B) of the base 20B. Moreover, also in the modification 2, the light source part 3B is arrange | positioned along a pair of side surfaces 24B and 25B of the base 20B of the optical member 2B. A pair of light sources 3B is provided at both ends of the optical member 2B. In addition, the light source part 3B may be provided only in one among the both ends of the optical member 2B.

  The light source unit 3B is different from the optical member 2A of Modification 1 described above in that the holding member 30B includes an absorption surface 50B or a scattering surface 51B described later. The holding member 30B absorbs light radiated from the light incident element 32 between the light incident element 32 of the light source unit 3B and the side surfaces 24B and 25B of the base part 20B at the ends of the side surfaces 24B and 25B of the base part 20B. The absorption surface 50B or the scattering surface 51B that scatters the light emitted from the light incident element 32 is provided. Thereby, the planar illumination device 1B can emit light having a non-uniform luminance distribution having a bright part and a dark part from the light extraction surface 21B of the base part 20B. In the example shown in FIG. 11, light having a uniform luminance distribution is incident on the side surfaces 24B and 25B of the optical member 2B, and the light is absorbed by the absorption surface 50B, or the light is scattered by the scattering surface 51B. . Thereby, the light radiated | emitted from the light extraction surface 21B can be made into the luminance distribution in which the bright part and dark part of a brightness | luminance were located in a line along the longitudinal direction of the base 20B.

  In addition, when providing the absorption surface 50B, you may form the absorption surface 50B using the surface to which the black coating was given, or the surface to which the black film was stuck, for example. When the scattering surface 51B is provided, for example, the scattering surface 51B may be formed using a surface on which minute irregularities are formed. Further, for example, the holding member 30B may include the absorption surface 50B or the scattering surface 51B at both ends, or may include the absorption surface 50B or the scattering surface 51B only at one of the ends. The absorption surface 50B and the scattering surface 51B may have any configuration as long as they have a desired absorption rate.

  When the absorption surface 50B is provided, the total light reflectance at the absorption surface 50B is at least 90% or less, preferably 80% or less, and more preferably 50% or less. Thereby, even if the light of uniform luminance distribution is radiated | emitted with respect to the side surfaces 24B and 25B of the optical member 2B, the planar illuminating device 1B is non-uniform | heterogenous which has a bright part and a dark part from the light extraction surface 21B of the base 20B. Light having a desired luminance distribution can be emitted. When the scattering surface 51B is provided, when the spread of light scattering on the scattering surface 51B is represented by a Gaussian distribution, the full width at half maximum of the Gaussian distribution is at least 5 degrees (°), preferably 15 degrees or more. More preferably, it is 30 degrees or more. Thereby, even if the light of uniform luminance distribution is radiated | emitted with respect to the side surfaces 24B and 25B of the optical member 2B, the planar illuminating device 1B is non-uniform | heterogenous which has a bright part and a dark part from the light extraction surface 21B of the base 20B. Light having a desired luminance distribution can be emitted.

  Each light source unit 3B is provided with a light source 31 at a position sandwiching the light incident element 32 from the longitudinal direction of the light incident element 32 (vertical direction in FIG. 11). For example, the two light sources 31 are arranged so that light enters the light incident element 32 from the side end portions of the light incident element 32. Note that only one light source 31 may be used as long as the desired light distribution control is performed. The light source 31 allows light to enter the light incident element 32 from one of the side end portions of the light incident element 32. You may arrange | position so that it may light. For example, the light incident element 32 has a function of converting light emitted from the light source 31 that is a point light source into light of a linear light source. For example, the light incident element 32 is formed of a light transmissive material. The light incident element 32 may be a so-called light bar.

  Further, the distance between the light source part 3B and the side surfaces 24B and 25B of the base part 20B is at least 0.1 mm to 20 mm, preferably 0.5 mm to 15 mm, and more preferably 1 mm to 10 mm. . Thereby, even if the light of uniform luminance distribution is radiated | emitted with respect to the side surfaces 24B and 25B of the optical member 2B, the planar illuminating device 1B is non-uniform | heterogenous which has a bright part and a dark part from the light extraction surface 21B of the base 20B. Light having a desired luminance distribution can be emitted.

  As shown in FIG. 12, the luminance distribution 4B in the vertical direction of the light extraction surface 21B, which is a light emitting area in the base 20B, has a bright portion 40B and a dark portion 41B. By absorbing or scattering the light incident on the side surfaces 24B and 25B of the base portion 20B, the light reflection component is reduced and the dark portion 41B is generated. As described above, in the luminance distribution 4B on the light extraction surface 21B, for example, when the light extraction surface 21B is viewed from an oblique direction, the dark portion 41B is visually recognized, and the luminance looks uneven. As shown in FIG. 12, the luminance distribution 4B on the light extraction surface 21B has a linear dark portion 41B in the bright portion 40B on one surface. The dark part 41B extends toward the center of the lateral direction of the side surfaces 24B and 25B as the distance from the light source part 3B in the longitudinal direction of the base part 20B increases. In the luminance distribution 4B on the light extraction surface 21B, the bright portion 40B and the dark portion 41B are arranged in a direction orthogonal to the side surfaces 24B and 25B of the base 20B. The boundary between the bright portion 40B and the dark portion 41B is inclined with respect to a line orthogonal to the side surfaces 24B and 25B of the base portion 20B. In addition, the line orthogonal to the side surfaces 24B and 25B of the base 20B corresponds to the longitudinal line of the base 20B in the example of FIG.

  As described above, the boundary between the bright part 40B and the dark part 41B is inclined, so that a pictorial depth feeling (perspective) that extends from the front to the back can be created on the light extraction surface 21B. Thereby, the person who has seen the emitted light emitting surface (light extraction surface 21B) can perceive the boundary between the inclined bright part 40B and the dark part 41B, and light is emitted by the boundary between the inclined bright part 40B and the dark part 41B. The surface can be perceived as having a depth that extends from the front to the back. Thereby, for example, the visual effect can be enhanced with a configuration that does not use binocular parallax.

  Note that the inclination angle of the boundary between the bright part 40B and the dark part 41B in the luminance distribution 4B varies depending on the position of the viewpoint of the person viewing the light emitting surface. Also in the example shown in FIG. 12, the boundary between the bright portion 40B and the dark portion 41B extending from both side edges of the light extraction surface 21B intersects in the vicinity of the center in the longitudinal direction of the base portion 20B. Depending on the position, the base 20B moves in the direction along the longitudinal direction.

(Modification 3-1)
Next, a planar lighting device 1C according to Modification 3-1 will be described with reference to FIGS. FIG. 13 is a front view showing a planar illumination device according to Modification 3-1. FIG. 14 is a diagram illustrating a luminance distribution on the light extraction surface according to Modification 3-1. In addition, in FIG. 14, the case where the planar illuminating device 1C is seen from diagonally upward in the front is shown. Moreover, in FIG. 14, the simulation result of the lighting state of 1 C of planar illumination apparatuses is shown. Moreover, the luminance distribution 4C shown in FIG. 14 is an example, and the aspect of the luminance distribution 4C is not limited to this.

  As illustrated in FIG. 13, the planar illumination device 1 </ b> C includes an optical member 2 </ b> C and a light source unit 3 </ b> C. The optical member 2C has a base portion 20C that is a transparent body formed in a flat plate shape. Also in the optical member 2 </ b> C, one surface 21 </ b> C (hereinafter also referred to as “light extraction surface 21 </ b> C”) illustrated in FIG. 13 is a light emitting surface. The optical member 2C is the same as the optical member 2 of the above-described embodiment.

  As illustrated in FIG. 13, the light source unit 3 </ b> C includes a holding member 30 </ b> C, a light source 31, and a light incident element 32. Also in the modified example 3-1, the light source unit 3C is disposed along the pair of side surfaces 24C and 25C of the base 20C of the optical member 2C. A pair of light sources 3C is provided at both ends of the optical member 2C. The light source unit 3C may be provided on only one of both end portions of the optical member 2C.

  The light source unit 3C is different from the light source units 3A and 3B of Modification 1 and Modification 2 described above in the arrangement of the light source 31, and one light source 31 is disposed in each light source unit 3C. In the modified example 3-1, the light source 31 is disposed on one side in the width direction of the holding member 30C (that is, the direction orthogonal to the side surfaces 24C and 25C of the base portion 20C). Light is emitted from the light incident element 32 of the light source unit 3C toward one half of the base 20C in the direction orthogonal to the side surfaces 24C and 25C. For example, the light source 31 is disposed only in one of the light incident elements 32 having a light distribution property that uniformly radiates light from the light sources 31 at both ends of the light incident element 32 as in the first and second modifications. The planar illumination device 1C can emit light having a non-uniform luminance distribution having a bright part and a dark part from the light extraction surface 21C of the base part 20C. In addition, also in FIG. 13, the light emitted from the light extraction surface 21C can be a luminance distribution in which bright portions and dark portions of luminance are aligned along the longitudinal direction of the base portion 20C.

  As shown in FIG. 14, the luminance distribution 4C in the vertical direction of the light extraction surface 21C, which is a light emitting area in the base 20C, has a bright portion 40C and a dark portion 41C. The luminance distribution 4C on the light extraction surface 21C looks uneven in luminance. As shown in FIG. 14, the luminance distribution 4C on the light extraction surface 21C has a dark part 41C on one side of the holding member 30C where the light source 31 is disposed. The dark part 41C extends toward the center of the lateral direction of the side surfaces 24C and 25C as the distance from the light source part 3C in the longitudinal direction of the base part 20C increases. In the luminance distribution 4C on the light extraction surface 21C, the bright portion 40C and the dark portion 41C are arranged in a direction orthogonal to the side surfaces 24C and 25C of the base portion 20C. The boundary between the bright portion 40C and the dark portion 41C is inclined with respect to a line orthogonal to the side surfaces 24C and 25C of the base portion 20C. In addition, the line orthogonal to the side surfaces 24C and 25C of the base portion 20C corresponds to the longitudinal line of the base portion 20C in the example of FIG.

  As described above, the boundary between the bright part 40C and the dark part 41C is inclined, so that it is possible to create a pictorial depth (perspective) that extends from the front to the back on the light extraction surface 21C. Thereby, the person who has seen the emitted light emitting surface (light extraction surface 21C) can perceive the boundary between the inclined bright part 40C and the dark part 41C, and light is emitted by the boundary between the inclined bright part 40C and the dark part 41C. The surface can be perceived as having a depth that extends from the front to the back. Thereby, for example, the visual effect can be enhanced with a configuration that does not use binocular parallax.

  In addition, the inclination angle of the boundary between the bright part 40C and the dark part 41C in the luminance distribution 4C varies depending on the position of the viewpoint of the person viewing the light emitting surface. Also in the example shown in FIG. 14, the boundary between the bright portion 40C and the dark portion 41C extending from both side edges of the light extraction surface 21C intersects in the vicinity of the center in the longitudinal direction of the base portion 20C. Depending on the position of the base, the base 20C moves in a direction along the longitudinal direction.

(Modification 3-2)
Next, a planar lighting device 1D according to Modification 3-2 will be described with reference to FIGS. 15 and 16. FIG. 15 is a front view illustrating a planar illumination device according to Modification 3-2. FIG. 16 is a diagram illustrating a luminance distribution on the light extraction surface according to Modification 3-2. In addition, in FIG. 16, the case where planar illumination device 1D is seen from diagonally upward in the front is shown. Moreover, in FIG. 16, the simulation result of the lighting state of the planar illuminating device 1D is shown. Moreover, the luminance distribution 4D shown in FIG. 16 is an example, and the aspect of the luminance distribution 4D is not limited to this.

  As shown in FIG. 15, the planar illumination device 1D includes an optical member 2D and a light source unit 3D. The optical member 2D has a base 20D that is a transparent body formed in a flat plate shape. Also in the optical member 2D, one surface 21D (hereinafter, also referred to as “light extraction surface 21D”) shown in FIG. 15 is a light emitting surface. The optical member 2D is the same as the optical member 2 of the above-described embodiment.

  As illustrated in FIG. 15, the light source unit 3 </ b> D includes a holding member 30 </ b> D, a light source 31, and a light incident element 32. Also in Modification 3-2, the light source unit 3D is disposed along the pair of side surfaces 24D and 25D of the base 20D of the optical member 2D. A pair of light sources 3D is provided at both ends of the optical member 2D.

  The light source unit 3D is different from the light source unit 3C of Modification 3-1 described above in the arrangement of the light source 31. In Modification 3-2, the light source 31 is disposed on the other side in the width direction of the holding member 30D (that is, the direction orthogonal to the side surfaces 24D and 25D of the base 20D). Light is emitted from the light incident element 32 of the light source unit 3D toward the other half of the base 20D in the direction orthogonal to the side surfaces 24D and 25D. For example, the light source 31 is disposed only in one of the light incident elements 32 having a light distribution property that uniformly radiates light from the light sources 31 at both ends of the light incident element 32 as in the first and second modifications. The planar illumination device 1D can emit light having a nonuniform luminance distribution having a bright part and a dark part from the light extraction surface 21D of the base part 20D. Also in the example shown in FIG. 15, the light emitted from the light extraction surface 21 </ b> D can have a luminance distribution in which bright portions and dark portions of luminance are aligned along the side surfaces 24 </ b> D and 25 </ b> D of the base portion 20 </ b> D.

  As shown in FIG. 16, the luminance distribution 4D in the vertical direction of the light extraction surface 21D, which is a light emitting area in the base portion 20D, has a luminance bright portion 40D and a dark portion 41D. Thus, the luminance distribution 4D on the light extraction surface 21D has the bright portion 40D and the dark portion 41D, and thus the luminance is not uniform. That is, the luminance distribution 4D on the light extraction surface 21D has nonuniform luminance. As shown in FIG. 16, in the luminance distribution 4D on the light extraction surface 21D, the holding member 30D has a dark part 41D on the other side where the light source 31 is disposed. The dark part 41D extends toward the center of the lateral direction of the side surfaces 24D and 25D as the distance from the light source part 3D in the longitudinal direction of the base part 20D increases. In the luminance distribution 4D on the light extraction surface 21D, the bright portion 40D and the dark portion 41D are arranged in a direction orthogonal to the side surfaces 24D and 25D of the base portion 20D. The boundary between the bright part 40D and the dark part 41D is inclined with respect to a line orthogonal to the side surfaces 24D and 25D of the base part 20D. Note that the lines orthogonal to the side surfaces 24D and 25D of the base 20D correspond to the longitudinal lines of the base 20D in the example of FIG.

  As described above, the boundary between the bright part 40D and the dark part 41D is inclined, so that a pictorial depth feeling (perspective) that extends from the front to the back can be created on the light extraction surface 21D. Thereby, the person who has seen the emitted light emitting surface (light extraction surface 21D) can perceive the boundary between the inclined bright part 40D and the dark part 41D, and light is emitted by the boundary between the inclined bright part 40D and the dark part 41D. The surface can be perceived as having a depth that extends from the front to the back. Thereby, for example, the visual effect can be enhanced with a configuration that does not use binocular parallax.

  Note that the inclination angle of the boundary between the bright part 40D and the dark part 41D in the luminance distribution 4D varies depending on the position of the viewpoint of the person viewing the light emitting surface. Also in the example shown in FIG. 16, the boundary between the bright portion 40D and the dark portion 41D extending from both side edges of the light extraction surface 21D intersects in the vicinity of the center in the longitudinal direction of the base portion 20D. Depending on the position, the base 20D moves in a direction along the longitudinal direction.

(Modification 3-3)
Next, a planar lighting device 1E according to Modification 3-3 will be described with reference to FIGS. FIG. 17 is a front view showing a planar illumination device according to Modification 3-3. FIG. 18 is a diagram illustrating a luminance distribution on the light extraction surface according to Modification 3-3. In addition, in FIG. 18, the case where the planar illuminating device 1E is seen from diagonally upward in the front is shown. Moreover, in FIG. 18, the simulation result of the lighting state of the planar illuminating device 1E is shown. Moreover, the luminance distribution 4E shown in FIG. 18 is an example, and the aspect of the luminance distribution 4E is not limited to this.

  As shown in FIG. 17, the planar illumination device 1E includes an optical member 2E and a light source unit 3E. The optical member 2E has a base portion 20E that is a transparent body formed in a flat plate shape. Also in the optical member 2E, one surface 21E shown in FIG. 17 (hereinafter also referred to as “light extraction surface 21E”) serves as a light emitting surface. The optical member 2E is the same as the optical member 2 of the above-described embodiment.

  As illustrated in FIG. 17, the light source unit 3 </ b> E includes a holding member 30 </ b> E, a light source 31, and a light incident element 32. Also in Modified Example 3-3, the light source unit 3E is disposed along the pair of side surfaces 24E and 25E of the base 20E of the optical member 2E. A pair of light sources 3E is provided at both ends of the optical member 2E.

  The light source unit 3E is different from the light source units 3C and 3D of the modified example 3-1 and modified example 3-2 described above in the arrangement of the light source 31. In Modification 3-3, the light source 31 is arranged on one side in the width direction of one holding member 301E (that is, the direction orthogonal to the side surfaces 24E and 25E of the base 20E). In Modification 3-3, the light source 31 is disposed on the other side in the width direction of the other holding member 302E (that is, the direction orthogonal to the side surfaces 24E and 25E of the base portion 20E).

  Light is emitted from the light incident element 32 of the light source unit 3E held by one holding member 301E toward one half of the base 20E in the direction orthogonal to the side surfaces 24E and 25E. Light is emitted from the light incident element 32 of the light source 3E held by the other holding member 302E toward the other half of the base 20E in a direction orthogonal to the side surfaces 24E and 25E. For example, the light source 31 is disposed only in one of the light incident elements 32 having a light distribution property that uniformly radiates light from the light sources 31 at both ends of the light incident element 32 as in the first and second modifications. The planar illumination device 1E can emit light having a nonuniform luminance distribution having a bright part and a dark part from the light extraction surface 21E of the base part 20E. In the example shown in FIG. 17 as well, the light emitted from the light extraction surface 21E can be a luminance distribution in which bright and dark portions of luminance are arranged along the side surfaces 24E and 25E of the base 20E.

  As shown in FIG. 18, the luminance distribution 4E in the vertical direction of the light extraction surface 21E, which is a light emitting area in the base 20E, has a bright portion 40E and a dark portion 41E. Thus, the luminance distribution 4E on the light extraction surface 21E looks uneven in luminance. As shown in FIG. 18, in the luminance distribution 4E on the light extraction surface 21E, the dark portion 41E is provided on the side (one side) where the light source 31 of one holding member 301E is disposed with the center in the longitudinal direction of the base portion 20E as a boundary. The other holding member 302E has a dark portion 41E on the side where the light source 31 is disposed (the other side).

  The dark part 41E on one side extends toward the center in the short side direction of the side surfaces 24E and 25E as the distance from the light source part 3E in the longitudinal direction of the base part 20E increases. On the other hand, the dark side 41E on the other side extends toward one end of the side surfaces 24E and 25E in the short direction as the distance from the light source 3E in the longitudinal direction of the base 20E increases. In the luminance distribution 4E on the light extraction surface 21E, the bright portion 40E and the dark portion 41E are arranged in a direction orthogonal to the side surfaces 24E and 25E of the base portion 20E. The boundary between the bright part 40E and the dark part 41E is inclined with respect to a line orthogonal to the side surfaces 24E and 25E of the base part 20E. In addition, the line orthogonal to the side surfaces 24E and 25E of the base 20E corresponds to the longitudinal line of the base 20E in the example of FIG.

  As described above, the boundary between the bright part 40E and the dark part 41E is inclined, so that a pictorial depth feeling (perspective) that extends from the front to the back can be brought about on the light extraction surface 21E. Thereby, the person who has seen the emitted light emitting surface (light extraction surface 21E) can perceive the boundary between the inclined bright part 40E and the dark part 41E, and light is emitted by the boundary between the inclined bright part 40E and the dark part 41E. The surface can be perceived as having a depth that extends from the front to the back. Thereby, for example, the visual effect can be enhanced with a configuration that does not use binocular parallax.

  Note that the inclination angle of the boundary between the bright part 40E and the dark part 41E in the luminance distribution 4E varies depending on the position of the viewpoint of the person viewing the light emitting surface. Also in the example shown in FIG. 18, the boundary between the bright portion 40E and the dark portion 41E extending from both side edges of the light extraction surface 21E intersects in the vicinity of the center in the longitudinal direction of the base portion 20E. Depending on the position, the base 20E moves in a direction along the longitudinal direction.

  In the above-described embodiment and the modification of the embodiment, the configuration in which the light source unit is disposed on each of the pair of side surfaces of the base portion of the optical member has been described. For example, the light source unit is only one of the pair of side surfaces. May be arranged. Even if comprised in this way, the light radiated | emitted from a light extraction surface will have a luminance distribution which has a bright part and a dark part of a brightness | luminance, and inclines in the longitudinal direction of a base.

  Further, in the above-described embodiment and the modification of the embodiment, the light emitted from the light extraction surface by the configuration of the light source unit, the absorption surface or the scattering surface is a luminance distribution having a bright part and a dark part. For example, the luminance distribution having a bright part and a dark part may be used for the light emitted from the light extraction surface by the prism part in which the pitch and angle are appropriately defined.

  Moreover, although it was set as the structure provided with one light incident element for every light source part in the modification of above-described embodiment, multiple light incident elements may be laminated | stacked, for example. The light incident element may be formed in a wedge shape, and the light source may be disposed on one side, or the wedge-shaped light incident elements may be disposed to face each other. When the wedge-shaped light incident element is arranged on one side, for example, the light incident element is formed so that the thickness decreases as it goes in one direction along the short direction of the base. In addition, when the wedge-shaped light incident elements are arranged to face each other, for example, the two light incident elements are formed so that the thickness decreases in one direction or the other direction along the short direction of the base, and Are arranged with their inclined surfaces facing each other. In addition, the light incident element may be formed with a prism that is partially angle-adjusted so that the luminance of emitted light is non-uniform, or may not be partially formed. Moreover, you may arrange | position the member by which the transmittance | permeability was controlled between the light-receiving element and the side surface of the base.

  Note that the above-described planar illumination device may be used for a high mount of an automobile. For example, the planar lighting device may be attached to the rear window of an automobile. Moreover, an optical member is not limited to the object for motor vehicles, You may be used for the planar illuminating device of various uses.

  Further, the present invention is not limited by the above embodiment. What was comprised combining each component mentioned above suitably is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

DESCRIPTION OF SYMBOLS 1 Planar illuminating device 2 Optical member 20 Base 24 Side surface 25 Side surface 3 Light source part 4 Luminance distribution 40 Bright part 41 Dark part

Claims (15)

An optical member having a base formed in a flat plate shape;
A light source portion disposed along a side surface of the base portion of the optical member,
A planar illumination device in which a boundary between a bright part and a dark part is inclined with respect to a line orthogonal to the side surface in a luminance distribution in the base part of light incident from the light source part.   The base portion of the optical member is a transparent body, and is a prism portion formed on one side in the thickness direction of the base portion and arranged in a predetermined direction, and the thickness direction of the base portion in a cross section along the predetermined direction is A second region having a prism shape is continuous with a first region having an inclination angle with respect to the orthogonal plane of 0 degrees or more and within 8 degrees, and the ratio of the first region in the length in the predetermined direction is 60% or more and 100. The planar illumination device according to claim 1, comprising a prism portion that is less than%.   The planar illumination device according to claim 1, wherein the light source unit emits light so as to have a nonuniform luminance distribution on the side surface of the base.   3. The planar illumination device according to claim 2, wherein a luminance ratio between a bright part and a dark part in a luminance distribution of light emitted from the light source unit is at least 80% or less in a state where the side surface is focused.   The planar illumination device according to claim 4, wherein a luminance ratio of a bright part and a dark part in a luminance distribution of light emitted from the light source unit is 50% or less in a state where the side surface is focused.   The planar illumination device according to claim 2, wherein the light source unit includes a plurality of light sources arranged along the side surface of the base. The light source unit emits light so as to have a uniform luminance distribution on the side surface of the base,
The surface illumination device according to claim 1, wherein a surface orthogonal to the side surface of the base portion is a light absorption surface or a scattering surface.   The planar illumination device according to claim 7, wherein the light absorption at the absorption surface or the scattering surface is at least 0.05 or more.   The planar illumination device according to claim 8, wherein an absorbance of light on the absorption surface or the scattering surface is 0.3 or more. The light source unit emits light so as to have a uniform luminance distribution on the side surface of the base,
The planar illumination device according to claim 2, further comprising a light absorbing surface or a light scattering surface at an end portion of the base portion between the light source portion and the base portion and oriented in a direction orthogonal to the side surface.   When the distance between the light source part and the base part is at least 0.1 mm or more and 20 mm or less and includes the absorption surface, the total reflectance of light at the absorption surface is at least 90% or less, and the scattering surface is 11. The planar illumination device according to claim 10, wherein the full width at half maximum of the Gaussian distribution is at least 5 degrees or more when the spread of light scattering on the scattering surface is expressed by a Gaussian distribution.   The planar illumination device according to claim 11, wherein a distance between the light source unit and the base unit is 1 mm or more and 10 mm or less.   The planar illuminating device of Claim 11 or 12 whose total reflectance in the said absorption surface is 50% or less.   The planar illumination device according to any one of claims 11 to 13, wherein a full width at half maximum in the Gaussian distribution is 30 degrees or more when a spread of light scattering on the scattering surface is expressed by a Gaussian distribution.   The planar illumination device according to claim 1, wherein the light source unit emits light toward one half or the other half of the base portion in a direction orthogonal to the side surface.