JP2014145824A - Light source module and display device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source module that is thin, can achieve high-quality illumination without luminance unevenness, and can suppress, when used as a display device for double-sided display, an image on one side from being captured in the other surface; and a display device including the light source module.SOLUTION: A backlight module (10A) includes an LED (13b), and a light guide plate (11) that couples light beams from the LED (13b) made incident on an incidence surface (11a), makes the light beams propagate inside thereof, and takes out the light beams to the outside. The light guide plate (11) has light diffusion members (12, 12) disposed respectively on both sides. The refractive index of the light diffusion members (12, 12) is higher than the transmittance of the light diffusion members (12, 12).

Description

  The present invention relates to a light source module and a display device using the same, and more particularly, to a light source module that is thin for a double-sided display and a display device using the same.

  2. Description of the Related Art Conventionally, an electric signboard 100 that illuminates and displays an image layer on which an image is printed or the like is arranged with several fluorescent lamps 102 in a housing 101, for example, as shown in FIG. The arranged image layer 103 is illuminated.

  In the electric signboard 100 having such a structure, in order to prevent the shape of the fluorescent lamp 102 from being raised, the distance between the fluorescent lamp 102 and the image layer 103 needs to be separated by about 15 to 20 cm, and the thickness is large. There is a drawback of becoming. In particular, in recent years, it may be required to observe images from both sides, and when the distance between the fluorescent lamp 102 and the image layers 103 on both sides is increased, the thickness becomes even thicker.

  Therefore, as a solution to reducing the thickness while observing images from both sides, for example, in Patent Document 1, as shown in FIG. 10, the light guide plates 211 and 211 are back to back and back to back. There has been proposed an electric signboard 200 using a backlight 210 in which a reflection film 212 is sandwiched between 211 and 211 and a light source 213 is disposed on the side ends of the light guide plates 211 and 211 back to back. In this electric signboard 200, the light source 213 is turned on so that light is emitted from both light guide plates 201 and 201 to both sides, and the images of the display panels 201 and 201 on both sides are displayed.

  In this electric signboard 200, since the light source 213 can be disposed at the side end portions of the light guide plates 201 and 201, the thickness can be made thinner than the conventional electric signboard.

JP 2004-13072 A (published January 15, 2004)

  However, in the conventional light source module disclosed in Patent Document 1 and a display device such as an electric signboard provided with the light source module, since two light guide plates 211 and 211 are provided, the light source module and the light source module are provided. There is a problem that the thickness of the display device is not sufficiently thin.

  On the other hand, if the thickness of the light source module and the display device is reduced, for example, the light on the back side may affect the front side, resulting in uneven brightness on the front side. Further, when such a light source module is used in a display device such as an electric signboard, there is a problem in that an image on one side is displayed on the other side when images are displayed on both sides.

  The present invention has been made in view of the above-described conventional problems, and the object thereof is thin, can realize high-quality illumination with no luminance unevenness, and when used as a display device for double-sided display, An object of the present invention is to provide a light source module capable of suppressing an image of one surface from being reflected on the other surface and a display device including the light source module.

  In order to solve the above problems, a light source module according to an aspect of the present invention includes a light source and a light guide member that couples light from the light source from an end surface, propagates inside, and extracts the light to the outside. And the light diffusion member is disposed on both sides of the light guide member, and the reflectance of each light diffusion member is higher than the transmittance of each light diffusion member. .

  In order to solve the above problems, a display device according to an aspect of the present invention is a display device including the light source module described above, and image layers are provided on both sides of the light source module. It is said.

  According to one embodiment of the present invention, high-quality illumination that is thin and does not have uneven brightness can be realized, and when used as a display device for double-sided display, an image on one surface is reflected on the other surface. It is possible to provide a light source module capable of suppressing the above and a display device including the same.

It is sectional drawing which shows schematic structure of the electrical signboard in Embodiment 1 of this invention. It is a front view which shows the structure of the backlight module as a light source module with which the said electrical decoration signboard was equipped. It is an electrical decoration signboard of a comparative example, Comprising: It is sectional drawing which shows the principle of the reflection phenomenon to the surface side of the image of the image film of the back side in an electrical decoration signboard provided with the light-diffusion member with a low reflectance. The cross section which shows the electrical decoration signboard in the said Embodiment 1, Comprising: The principle which eliminates the reflection phenomenon to the surface side of the image of the image film of the back side in an electrical decoration signboard provided with the light-diffusion member with a high reflectance. FIG. It is sectional drawing which shows the scattering effect of the light-scattering part in the said electrical decoration signboard. The electric signboard in Embodiment 2 of this invention is shown, Comprising: It is sectional drawing which shows schematic structure of an electric signboard. It is a front view which shows the structure of the backlight module as a light source module with which the said electrical decoration signboard was equipped. The electric signboard in Embodiment 3 of this invention is shown, Comprising: It is sectional drawing which shows schematic structure of an electric signboard. It is sectional drawing which shows the structure of the conventional electrical signboard. It is sectional drawing which shows the structure of the other conventional electrical signboard.

[Embodiment 1]
One embodiment of the present invention will be described below with reference to FIGS.

  In this embodiment, an electronic signboard as an electronic device and a display device, and a backlight module as a light source module provided in the electric signboard will be described. However, the electronic device, the display device, and the light source module are not limited to this, and include, for example, a liquid crystal display device and an indoor lighting device as the electronic device and the display device, and the light that is part of the lighting device is used as the light source module. A light emitting unit that emits light is included.

  First, configurations of an electronic device including a backlight module as a light source module of the present embodiment and an electric signboard 1A as a display device will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a schematic configuration of an electric signboard in the present embodiment. FIG. 2 is a front view showing a configuration of a backlight module as a light source module provided in the electric signboard.

  As shown in FIG. 1, the electric signboard 1 </ b> A according to the present embodiment has cover members 2, 2, frames 3, 3 provided at the top and bottom, a backlight module 10 </ b> A as a light source module, and an image printed Image films 4a and 4b as the image layers thus formed, protective plates 5 and 5 for protecting the image films 4a and 4b, and a controller 6 are provided.

  Two light diffusion members 12 and 12 are arranged inside the cover members 2 and 2 and the frames 3 and 3 so as to sandwich a light guide plate 11 as a light guide member. Further, a light source group 13 is disposed on one side of the light guide plate 11, and the frames 3 and 3 sandwiching the light diffusion members 12 and 12 are attached so as to cover the light source group 13. The light source group 13 is connected to the control unit 6.

  The backlight module 10 </ b> A includes the light guide plate 11, light diffusion members 12 and 12, and a light source group 13.

  The light source group 13 is provided, for example, on one side in the longitudinal direction of the light guide plate 11, and the light source group 13 is a circuit board 13a and a circuit board 13a mounted as a light source mounted at a distance from each other. It consists of a plurality of LEDs (Light Emitting Diodes) 13b.

  In the present embodiment, the light guide plate 11 is composed of a light guide having a substantially rectangular parallelepiped shape, and is composed of one layer in the thickness direction. Also, the planar direction is composed of a single sheet in the present embodiment. As described above, the light guide plate 11 according to the present embodiment is composed of one light guide in the planar direction. However, the present invention is not necessarily limited thereto, and for example, a plurality of divided flat plates. You may comprise from what arranged the light guide of the shape in the horizontal direction.

  As shown in FIG. 2, the light guide plate 11 has an incident surface 11 a on which the light from the LED 13 b is incident so as to face the LED 13 b. Further, as shown in FIG. 1, the light guide plate 11 has an exit surface 11c orthogonal to the entrance surface 11a and the facing surface 11b facing the entrance surface 11a. In addition, a light scattering portion 14 that is a light conversion member to be described later is formed on an emission surface 11d that is a surface facing the emission surface 11c.

  The light guide plate 11 propagates the light incident from the incident surface 11a through the light guide plate 11 while being totally reflected between the exit surfaces 11c and 11d and between the side surfaces 11e and 11f shown in FIG. Then, the total reflection condition is broken due to scattering by the light scattering portion 14 so that light is emitted from the emission surfaces 11c and 11d.

  Hereinafter, the components of the electric signboard 1A will be described in detail.

  First, in the backlight module 10A in the present embodiment, an LED 13b is employed as a light source. However, the present invention is not necessarily limited to this, and for example, a fluorescent tube or other light source can be employed.

  The frame 3 provided in the lower part fixes the LED 13b as a light source, and the frames 3 and 3 provided in the upper and lower parts sandwich and fix the light guide plate 11 and the light diffusion members 12 and 12. In addition, the frames 3 and 3 provided at the upper and lower parts have an effect of radiating heat generated by the fixed LED 13b. For this reason, it is preferable to use a metal material with high thermal conductivity for the frame 3, and it is more preferable to use a material made of, for example, aluminum (Al). Further, for fixing the LED 13b, a double-sided tape having high thermal conductivity may be used, or a screw may be fixed.

  The light diffusing members 12 and 12 have an effect of diffusing light and an effect of reflecting light. That is, in the present embodiment, the reflectance of each of the light diffusing members 12 and 12 is higher than the transmittance of the light diffusing members 12 and 12. Thereby, the light diffusing members 12 and 12 have a function of suppressing unevenness in luminance of light emitted from the light guide plate 11 and suppressing reflection of the image on the back side by the light diffusing effect and the light reflecting effect. ing.

  Here, the number and the combination of the light diffusing members 12 are not limited in order to have desired optical performance. As the material, for example, a material containing a diffusing agent based on polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS) or the like is used.

  The control unit 6 can control ON / OFF of the LED 13b and light amount output. The output of the LED 13b can be controlled by adjusting the amount of current, pulse width modulation (PWM), or the like.

  The image films 4a and 4b are films on which an image to be displayed on the electric signboard 1A is printed, and the material is not particularly limited as long as the image is printed. In general, a material having polyethylene terephthalate (PET) as a base material and a fixing agent or the like applied to the surface of the polyethylene terephthalate (PET) film so that the printing ink is easily fixed is used.

  The protective plates 5 and 5 are intended to prevent the image films 4a and 4b from being scratched or soiled. The protective plates 5 and 5 are made of a transparent material having a high light transmittance so as not to damage the images of the image films 4a and 4b to be protected. For example, PMMA (acrylic) or PC (polycarbonate) is used. PS (polystyrene) or the like is used. PC is preferable from the viewpoint of scratch resistance and environmental resistance.

  The cover members 2 and 2 have a function of pressing and holding the image films 4a and 4b and the protection plates 5 and 5 and a window portion that allows the display area of the electric signboard 1A to be visually recognized.

  The light guide plate 11 is made of a transparent material having high light transmittance, and for example, polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), or the like is used.

  On the exit surface 11d of the light guide plate 11, a plurality of light scattering portions 14 which are optical path conversion members are formed at intervals. In the present embodiment, the light scattering portion 14 is formed in a dot shape, for example.

  The dot diameter of the light scattering portion 14 is formed so as to increase from the incident surface 11a side of the light guide plate 11 toward the opposing surface 11b. The light scattering portion 14 is disposed so as to be symmetric with respect to a virtual axis that passes through the center in the longitudinal direction of the light guide plate 11 and extends in the short direction of the light guide plate 11.

  One dot diameter of the light scattering portion 14 is, for example, not less than 0.2 mm and not more than 1.5 mm. In the present embodiment, the light scattering portion 14 has a dot shape. However, the light scattering portion 14 is not necessarily limited to this, and may be a line, an ellipse, or a rectangle, and has a function of scattering light, and diffuses depending on the size (length). It is only necessary to be able to control the amount of light.

  The light scattering portion 14 is formed, for example, by dispersing light scattering fine particles in a polymer and then printing the polymer on the exit surface 11d. A phosphor may be used as the light scattering particles. These light scattering portions 14 may be formed by inkjet. At this time, the light scattering particles are not included in the polymer formed by inkjet, and the effect of light refraction due to the shape of the polymer may be used. Further, the light scattering portion 14 may be configured by forming a fine uneven shape such as a prism on the exit surface 11d. Furthermore, you may comprise the light-scattering part 14 by giving laser processing and a blast process to 11d of output surfaces.

  As described above, by forming the light scattering portion 14 on the exit surface 11d, the optical path of the light propagating through the light guide plate 11 can be changed. Specifically, when light propagating inside the light guide plate 11 enters the light scattering portion 14 of the exit surface 11d, the light is scattered and the direction of traveling inside the light guide plate 11 is changed. As a result, at least a part of the light scattered by the light scattering portion 14 is not totally reflected by the emission surface 11c but is emitted to the outside from the emission surfaces 11c and 11d.

  The light that has entered the light guide plate 11 from the incident surface 11a is diffused and the amount of light is attenuated as the distance from the incident surface 11a and the side surfaces 11e and 11f increases. Therefore, as described above, the brightness of the light emitted from the exit surfaces 11c and 11d is increased by increasing the arrangement density by increasing the dot diameter of the light scattering portion 14 as the distance from the entrance surface 11a and the side surfaces 11e and 11f increases. It is possible to suppress the occurrence of variations in.

  Here, in the present embodiment, the light is incident on the light guide plate 11 from one side of the incident surface 11a. However, the present invention is not limited to this, as shown in FIGS. 6 and 7 of the second embodiment to be described later. The light may be incident from the opposite surface 11b opposite to the incident surface 11a, or may be incident from the side surfaces 11e and 11f, though not shown.

  Moreover, in the light-scattering part 14, although the light quantity taken out from the light-guide plate 11 with the dot diameter was adjusted, it is not necessarily this, You may control a density by changing the arrangement space | interval of a dot.

  Next, a phenomenon in which the image of the image film 4b on the back surface side in the electric signboard 1A of the present embodiment having the above-described configuration is reflected on the front surface side will be described with reference to FIGS. FIG. 3 shows a comparative example, and is a diagram illustrating the phenomenon of reflection on the front side of the image of the image film 4b on the back side of the electric signboard 80 including the light diffusing member 12 having a low reflectance. . FIG. 4 is a diagram for explaining the phenomenon of reflection on the front side of the image of the image film 4b on the back side in the electric signboard 1A including the light diffusing member 12 having a high reflectance in the present embodiment. FIG. 5 is a diagram for explaining the scattering effect of the light scattering portion 14 on the light propagating through the light guide plate 11 in the electric signboard 1A of the present embodiment and emitted to the outside by the light scattering portion 14.

  As shown in FIG. 3, in the electric signboard 80 including the light diffusing members 82 and 82 having low reflectance, the image of the image film 4 b arranged on the back surface side of the light guide plate 11 is the emission surface of the electric signboard 80. The external light L1 incident from the outside on the 11d side (indicated as “B surface side” in FIG. 3) transmits to the exit surface 11c side (indicated as “A surface side” in FIG. 3). At this time, the image shadow of the image film 4b is diffused by the light diffusing members 12 and 12, but only by the diffusing effect of the light diffusing members 12 and 12, the exit surface 11c side (in FIG. 3) which is the surface side of the light guide plate 11. An image shadow is reflected on the light diffusing member 12 (shown as “A side”).

  As for the light L2 emitted from the light guide plate 11, the light emitted to the emission surface 11d side (indicated as “B surface side” in FIG. 3) reaches the image film 4b and is transmitted to the outside. The portion is reflected by the surface of the image film 4b and the protective plate 5 and transmits to the opposite emission surface 11c side (indicated as “A surface side” in FIG. 3). At this time, similar to the above-described phenomenon, the image shadow of the image film 4b is reflected on the exit surface 11c side (indicated as “A surface side” in FIG. 3).

  On the other hand, as shown in FIG. 4, in the case of the electric signboard 1 </ b> A of the present embodiment including the light diffusing members 12 and 12 having a high reflectance, the emission surface 11 d side (“B side” in FIG. 4 is displayed. The image film 4b of FIG. 4 is obtained by external light l1 incident from the outside on the exit surface 11d side (indicated as “B surface side” in FIG. 4) of the electric signboard 1A. A part of the light is transmitted to the A side), but most of the light is reflected by the light diffusing member 12.

  That is, the image shadow of the image film 4b can reduce the amount of light transmitted to the exit surface 11c side (indicated as “A surface side” in FIG. 4) by the reflection effect of the light diffusing member 12, and is transmitted. Since light is diffused by the light diffusing member 12, it is possible to prevent image shadows from appearing on the light diffusing member 12 on the exit surface 11 c side (indicated as “A surface side” in FIG. 4), which is the surface side of the light guide plate 11. can do.

  Further, the light L2 emitted from the light guide plate 11 is also emitted to the emission surface 11d side (indicated as “B surface side” in FIG. 4), reaches the image film 4b, and a part of the light is reflected and opposite. The light is transmitted to the light exit surface 11c side (indicated as “A surface side” in FIG. 5), but as described above, due to the reflection effect of the light diffusing member 12, the light exit surface 11d side (in FIG. 4). It is possible to prevent the image shadow of the image film 4b (shown as “B side”) from appearing on the exit surface 11c side (shown as “A side” in FIG. 4).

  Next, as shown in FIG. 5, the light propagating through the light guide plate 11 and extracted by the light scattering portion 14 of the light guide plate 11 is repeatedly reflected on the surface of the light diffusion member 12 having a high reflectance. Eventually, however, most of the light passes through and is taken out of the electric signboard 1A. At this time, by being reflected by the light diffusion member 12 a plurality of times, the light extracted from a part of the light scattering portion 14 is transmitted to the outside in a form dispersed from a larger area of the light diffusion member 12. become. That is, it is possible to suppress the local increase in the amount of light and make the light uniform and take out to the outside. Furthermore, at the time of this transmission, light can be more uniformly transmitted to the outside by the diffusion effect of the light diffusion member 12. That is, more uniform surface light emission can be realized by the reflection effect and the diffusion effect of the light diffusion member 12.

  Thus, in the backlight module 10A of this embodiment and the electric signboard 1A provided with the same, the light guide plate 11 that couples the light from the LED 13b and the LED 13b from the end face, propagates inside, and takes out to the outside. In the backlight module 10 </ b> A including the light guide plate 11, the light guide plate 11 is composed of one layer, and the light diffusion members 12 and 12 are disposed on both sides of the light guide plate 11.

  Thereby, since the light guide plate 11 consists of one layer and the light diffusing members 12 and 12 can be composed of a thin sheet, the backlight module 10A can be thin. Therefore, it is possible to provide a backlight module 10A that is thinner than the conventional one.

  Moreover, in this Embodiment, the reflectance of each light-diffusion member 12 * 12 is higher than the transmittance | permeability of this light-diffusion member 12 * 12. This is because it has been confirmed by a performance evaluation experiment shown in an example described later.

  As a result, even if the external transmitted light L1 enters from one light diffusing member 12, the external transmitted light L1 is reflected by the one light diffusing member 12, so that the external transmitted light L1 is diffused by the other light. There is little going out through the member 12 to the outside.

  Therefore, the externally transmitted light L1 of one light diffusing member 12 hardly affects the light emitted from the other light diffusing member 12. As a result, it is possible to realize high quality illumination with no luminance unevenness. This is because the light of one image film 4b is emitted from the other image film 4a even when there is an electric signboard 1A provided with the image films 4a and 4b on both surfaces of the backlight module 10A. Does not affect. For this reason, the image of one side is not reflected on the other side.

  Therefore, it is possible to realize a high-quality illumination that is thin and does not have uneven brightness, and when used as an electric signboard 1A for double-sided display, it is possible to suppress the image of one surface from being reflected on the other surface. It is possible to provide the light module 10A and the electric signboard 1A including the light module 10A.

  Moreover, in the backlight module 10A of this Embodiment and the electrical signboard 1A provided with it, it is preferable that the reflectance of the light-diffusion member 12 * 12 is 78% or more.

  Thereby, it is possible to surely realize high-quality illumination with no luminance unevenness, and when used as a double-sided electric signboard 1A, a backlight capable of suppressing an image on one surface from being reflected on the other surface A module 10A and an electric signboard 1A including the module 10A can be provided.

  In the backlight module 10A of the present embodiment, the light source is the LED 13b. As a result, the LED 13b is small, has a large amount of light, has low power consumption, and has a long lifetime. Therefore, the LED 13b is suitable as a light source for the backlight module 10A including the light guide plate 11.

  In addition, the electric signboard 1A of the present embodiment includes the backlight module 10A of the present embodiment, and image films 4a and 4b are disposed on both sides of the backlight module 10A.

  Such an electrical decoration signboard 1A has a problem that an image on one side is displayed on the other side when images are displayed on both sides.

  However, the electrical signboard 1A of the present embodiment includes the backlight module 10A of the present embodiment. Therefore, it is possible to realize a high-quality illumination that is thin and does not have uneven brightness, and when used as an electric signboard 1A for double-sided display, it is possible to suppress the image of one surface from being reflected on the other surface. The electric signboard 1A provided with the light module 10A can be provided.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. The configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and explanation thereof is omitted.

  In the backlight module 10 </ b> A as the light source module of the first embodiment and the electric signboard 1 </ b> A having the same, the LED 13 b as the light source is provided only on one side of the light guide plate 11. However, the backlight module 10B as the light source module and the electric signboard 1B having the light source module of the present embodiment are different in that LEDs 13b and 13b as light sources are provided on two opposite sides of the light guide plate 11. Yes.

  The structure of the backlight module 10B as a light source module of this Embodiment and the electrical signboard 1B provided with it is demonstrated based on FIG.6 and FIG.7. FIG. 6 is a cross-sectional view showing a schematic configuration of the electric signboard 1B in the present embodiment. FIG. 7 is a front view showing a configuration of a backlight module 10B as a light source module provided in the electric signboard 1B.

  As shown in FIG. 6, the backlight module 10 </ b> B and the electric signboard 1 </ b> B including the backlight module 10 </ b> B according to the present embodiment include a cover member 2, 2, frames 3, 3 provided on the upper and lower parts, and a backlight module 10 </ b> B. And image films 4a and 4b on which images are printed, protective plates 5 and 5 for protecting the image films 4a and 4b, and a control unit 6.

  Two light diffusion members 12 and 12 are arranged inside the cover members 2 and 2 and the frames 3 and 3 so as to sandwich a light guide plate 11 as a light guide member. Light source groups 13 and 13 are arranged on two sides of the light guide plate 11, and the frames 3 and 3 sandwiching the light diffusion members 12 and 12 are attached so as to cover the light source groups 13 and 13. ing. The light source groups 13 and 13 are connected to the control unit 6.

  The backlight module 10B includes the light guide plate 11, light diffusing members 12 and 12, and light source groups 13 and 13.

  As shown in FIG. 7, the light source groups 13 and 13 are provided on two sides in the longitudinal direction of the light guide plate 11. The light source groups 13 and 13 are provided on the circuit board 13a and the circuit board 13a. It consists of a plurality of LEDs (Light Emitting Diodes) 13b and 13b as light sources mounted at intervals.

  And in the backlight module 10B of the said structure and the electrical decoration signboard 1B provided with it, the light from LED13b * 13b is entered from two sides which the incident surface 11a and the opposing surface 11b of the light-guide plate 11 oppose. It has become.

  As a result, since the amount of light incident on the light guide plate 11 increases, it is possible to provide the backlight module 10B and the electric signboard 1B that can display the images of the image films 4a and 4b brighter.

  Here, the backlight module 10B and the electric signboard 1B according to the present embodiment are different from the backlight module 10A and the electric signboard 1A according to the first embodiment in that the LEDs 13b and 13b are opposed to the incident surface 11a of the light guide plate 11. Only the points of incidence and propagation from the two sides of the surface 11b are different, and the effect is the same as that of the backlight module 10A and the electric signboard 1A of the first embodiment.

  In addition, arrangement | positioning of LED13b * 13b of this Embodiment, the number of incident sides, etc. are not limited. The arrangement of the LEDs 13b and 13b is not limited to the two opposing sides of the light guide plate 11, but may be arranged in an L shape between the incident surface 11a and the side surface 11e of the light guide plate 11, for example. Moreover, you may arrange | position LED13b to all the three sides of the light-guide plate 11, or all four sides.

  As described above, the electrical signboard 1B of the present embodiment includes the backlight module 10B of the present embodiment, and the image films 4a and 4b are disposed on both sides of the backlight module 10B.

  Such an electrical decoration signboard 1B has a problem that an image on one side is displayed on the other side when images are displayed on both sides.

  However, the electrical signboard 1B of the present embodiment includes the backlight module 10B of the present embodiment. Therefore, it is possible to realize a high-quality illumination that is thin and does not have uneven brightness, and when used as an electric signboard 1B for double-sided display, it is possible to suppress the image of one surface from being reflected on the other surface. The electric signboard 1B provided with the light module 10B can be provided.

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to FIG. The configurations other than those described in the present embodiment are the same as those in the first embodiment and the second embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiment 1 and Embodiment 2 are given the same reference numerals, and explanation thereof is omitted.

  In the backlight module 10 </ b> A as the light source module of Embodiment 1 and the electric signboard 1 </ b> A including the backlight module 10 </ b> A, the light diffusion members 12 and 12 are provided in close contact with the light guide plate 11. However, in the backlight module 10 </ b> C as the light source module of the present embodiment and the electric signboard 1 </ b> C including the backlight module 10 </ b> C, at least one light diffusion member 12 is provided with a gap with respect to the light guide plate 11. Is different.

  A configuration of a backlight module 10C as a light source module of the present embodiment, an electronic apparatus including the backlight module 10C, and an electric decoration sign 1C as a display device will be described with reference to FIG. FIG. 8 is a cross-sectional view showing a schematic configuration of the electric signboard 1C in the present embodiment.

  As shown in FIG. 8, the backlight module 10 </ b> C and the electric signboard 1 </ b> C including the backlight module 10 </ b> C according to the present embodiment include cover members 2 and 2, frames 3 and 3 provided on the upper and lower portions, and a backlight module 10 </ b> C. And image films 4a and 4b on which images are printed, protective plates 5 and 5 for protecting the image films 4a and 4b, and a control unit 6.

  Two light diffusion members 12 and 12 are arranged inside the cover members 2 and 2 and the frames 3 and 3 so as to sandwich a light guide plate 11 as a light guide member. Further, a light source group 13 is disposed on one side of the light guide plate 11, and the frames 3 and 3 sandwiching the light diffusion members 12 and 12 are attached so as to cover the light source group 13. The light source group 13 is connected to the control unit 6.

  The backlight module 10 </ b> C includes the light guide plate 11, light diffusion members 12 and 12, and a light source group 13.

  And in this Embodiment, as shown in FIG. 8, the light-diffusion member 12 provided in the image film 4b side with respect to the light-guide plate 11 is arrange | positioned with the clearance gap 15 with the light-guide plate 11. As shown in FIG. ing.

  As described above, the backlight module 10 </ b> C of the present embodiment has the gap 15 between the light diffusion member 12 and the light guide plate 11. As a result, a larger light diffusion effect can be obtained, so that it is possible to suppress the reflection of the image of the image film 4b on the surface side of the light guide plate 11.

  Here, as shown in FIG. 8, in the backlight module 10 </ b> C of the present embodiment, the image film 4 b is a light diffusing member on the side having a gap 15 between the light guide plate 11 and the light diffusing member 12. 12 are arranged in close contact with each other, that is, with a distance of zero. Therefore, it can be said that the distance of the gap 15 between the light diffusion member 12 and the light guide plate 10 is larger than the distance between the light diffusion member 12 and the image film 4b.

  That is, when using a conventional light diffusing member having a low light reflectance of the light diffusing member 12, in order to enhance the light diffusing effect of the light diffusing member 12, the distance between the light diffusing member 12 and the image film 4 b is reduced. It is common to take a wide distance. This is because the light emitted from the light guide plate 10 and diffused at a wide angle by the light diffusing member 12 and emitted from the light diffusing member 12 to the image film 4b side is between the light diffusing member 12 and the image film 4b. This is because the effect of increasing the light uniformity (reflection prevention effect) can be obtained by sufficiently mixing and homogenizing.

  However, when the reflectance of the light diffusing member 12 is large as in the present embodiment, an effect of improving the luminance uniformity by increasing the distance between the light diffusing member 12 and the image film 4b can be expected. Further, the improvement in luminance uniformity by increasing the distance between the light guide plate 10 and the light diffusion member 12 is far greater than the effect. As a result, if the entire thickness including the image film 4b is the same, the distance between the light diffusion member 12 and the light guide plate 10 is larger than the distance between the light diffusion member 12 and the image film 4b. It can be said that it is advantageous to make the distance of the gap 15 larger than the distance between the light diffusion member 12 and the image film 4b.

  Note that the reason why the light uniformity increases when the distance of the gap 15 between the light guide plate 10 and the light diffusing member 12 is increased is that the reflection of the light diffusing member 12 is reflected as described in FIG. 4 and FIG. Since the rate is high, the light is diffused several times between the two light diffusing members 12 and then emitted to the outside. At this time, the greater the distance between the two light diffusing members 12 that are reflecting members, the higher the effect of light uniformity.

  In addition, the electrical signboard 1C of the present embodiment includes the backlight module 10C of the present embodiment, and image films 4a and 4b are disposed on both sides of the backlight module 10C.

  Such an electric signboard 1C has a problem in that an image on one side is displayed on the other side when images are displayed on both sides.

  However, the electrical signboard 1C of the present embodiment includes the backlight module 10C of the present embodiment. Therefore, it is thin and can realize high-quality illumination with no luminance unevenness, and when used as an electric signboard 1C for double-sided display, it is possible to prevent the image on one side from being reflected on the other side. The electric signboard 1C provided with the light module 10C can be provided.

  In the above description, the gap 15 is formed between the light diffusing member 12 and the light guide plate 11 provided on the image film 4b side with respect to the light guide plate 11. However, the present invention is not limited to this. For example, the gap 15 may be formed between the light diffusion member 12 provided on the image film 4 a side with respect to the light guide plate 11 and the light guide plate 11. Further, it is possible to form gaps 15 and 15 between the light guide plate 11 and the two light diffusing members 12 and 12, respectively, which is more preferable because a larger light diffusing effect can be obtained.

  In the present embodiment, the backlight module 10A as the light source module of the first embodiment and the electric signboard 1A including the backlight module 10A have been described. However, the present invention is not limited to this. It is also possible to form the gap 15 in the backlight module 10B as the light source module of the second embodiment and the electric signboard 1B including the backlight module 10B.

[Summary]
The light source module (backlight modules 10A, 10B, and 10C) according to aspect 1 of the present invention couples light from the light source (LED 13b) and the light source (LED 13b) from the end face (incident surface 11a), and propagates inside. In a light source module (backlight modules 10A, 10B, and 10C) including a light guide member (light guide plate 11) that is taken out to the outside, light diffusion members 12 and 12 are provided on both sides of the light guide member (light guide plate 11). Are disposed, and the reflectance of each of the light diffusing members 12 and 12 is higher than the transmittance of each of the light diffusing members 12 and 12.

  According to said structure, since the light-diffusion member 12 * 12 is each arrange | positioned on the both surfaces side of the light guide member (light guide plate 11), and a light-diffusion member can be comprised with a thin sheet | seat, it is thin as a light source module. Can be formed. Therefore, it is possible to provide a light source module that is thinner than the conventional one.

  In the present invention, the reflectance of each light diffusing member is higher than the transmittance of each light diffusing member. For this reason, even if external light enters from one light diffusing member, the external light is reflected by one light diffusing member, so that the external light does not escape to the outside through the other light diffusing member. Few.

  Therefore, the outside light from one light diffusing member hardly affects the light emitted from the other light diffusing member. As a result, it is possible to realize high quality illumination with no luminance unevenness. This means that the light of one image layer does not affect the light emitted from the other image layer even when there is a display device such as an electric signboard having image layers on both sides of the light source module. . For this reason, the image of one side is not reflected on the other side.

  Therefore, a light source module that can realize high-quality illumination that is thin and does not have uneven brightness, and can suppress an image on one surface from being reflected on the other surface when used as an electric signboard for double-sided display. In addition, a display device including the same can be provided.

  In the light source module (backlight modules 10A, 10B, and 10C) according to aspect 2 of the present invention, in the light source module (backlight modules 10A, 10B, and 10C) according to aspect 1, the reflectance of the light diffusing members 12 and 12 is 78. % Or more is preferable.

  Thereby, it is possible to surely realize high-quality illumination with no luminance unevenness, and when used as an electric signboard for double-sided display, a light source module capable of suppressing an image on one surface from being reflected on the other surface, and An electric signboard equipped with the same can be provided.

  In the light source module (backlight module 10C) according to aspect 3 of the present invention, in the light source module according to aspect 1 or 2, at least one of the light diffusion members 12 is a gap between the light guide member (light guide plate 11). 15 is preferably provided.

  As a result, since there is a gap between the diffusion member and the light guide member, light is diffused by the air layer in the progress of light from one diffusion member to the light guide member, and a large light diffusion effect is obtained. Can do.

  For this reason, the light from one diffusing member does not directly escape to the other diffusing member through the light guide member, but is relaxed, that is, blurred, so that high-quality illumination without uneven brightness can be realized, When used as an electric signboard for double-sided display, it is possible to provide a light source module capable of suppressing an image on one surface from being reflected on the other surface and an electric signboard including the light source module.

  In the light source module (backlight module 10C) according to aspect 4 of the present invention, in the light source module according to aspect 3, the side having the gap 15 between the at least one light diffusion member 12 and the light guide member (light guide plate 10). An image layer (image film 4b) is disposed outside the light diffusing member 12, and the distance of the gap 15 between the light diffusing member 12 and the light guide member (light guide plate 10) is determined as follows. It is characterized by being larger than the distance between the layer (image film 4b) and the light diffusing member 12.

  That is, when the reflectance of the light diffusing member is large as in one aspect of the present invention, the effect of improving the luminance uniformity by increasing the distance between the light diffusing member and the image layer can also be expected. The improvement in luminance uniformity by increasing the distance between the light guide member and the light diffusing member is far greater than the effect. As a result, if the total thickness including the image layer is the same, the distance between the light diffusing member and the light guide member is diffused more than the distance between the light diffusing member and the image layer is increased. It can be said that it is advantageous to make the distance larger than the distance between the member and the image layer.

  In the light source module (backlight module 10A / 10B / 10C) in aspect 5 of the present invention, in the light source module (backlight module 10A / 10B / 10C) of aspect 1, aspect 2 or aspect 3, the light source is a light emitting diode ( LED 13b).

  Accordingly, the light-emitting diode (LED 13b) is small in size, has a large amount of light, has low power consumption, and has a long life. Therefore, the light source of the light source module (backlight modules 10A, 10B, and 10C) including the light guide member. Suitable as

  In order to solve the above-mentioned problems, the display device (electric signboards 1A, 1B, and 1C) according to aspect 6 of the present invention has the light source module according to any one of aspects 1 to 4 (backlight modules 10A, 10B, and 10C). ) Provided with image layers (image films 4a and 4b) on both sides of the light source module (backlight modules 10A, 10B, and 10C). It is characterized by having.

  Therefore, a light source module that is thin and capable of realizing high-quality illumination with no luminance unevenness and that can suppress an image on one surface from being reflected on the other surface when used as a display device for double-sided display. A display device provided can be provided.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  In this example, the reflection of the image on the front side of the light guide plate 11 and the front luminance ratio of the image film 4b on the back side of the light guide plate 11 in the electric signboard 1A of the present embodiment and the front luminance ratio of the light diffusion member 12 are described. A confirmation experiment in which the reflectance and transmittance are changed will be described.

  First, the confirmation experiment was performed using the light diffusing member shown in Table 1.

  That is, as an example, Example 1 using the light diffusing member 12 having a total light transmittance of 56%, a reflectance of 40%, a light diffusion coefficient of 0.88, and a thickness of 5 mm, a total light transmittance of 20%, and a reflectance of 78. %, A light diffusion coefficient of 0.91 and a thickness of 5 mm, Example 1 using a light diffusion member 12 was evaluated for performance. As a comparative example, performance evaluation was performed using a light diffusion member having a total light transmittance of 40%, a reflectance of 55%, a light diffusion coefficient of 0.88, and a thickness of 5 mm.

  In addition, the optical value measurement of the light-diffusion coefficient (D) in a light-diffusion member was performed by the automatic variable angle photometer "brand name (GP-200): Murakami Color Laboratory Co., Ltd. make", and it computed by following Formula.

here,
θ: Light receiving angle T _θ : Light transmittance at θ degrees B _θ : Brightness at θ degrees Further, the light diffusion coefficient (D) was determined by the light receiving angle 5 ° of the brightness _{B 5,} the light receiving angle 20 ° of the brightness _{B 20} and the light receiving angle 70 ° Brightness _{B 70.}

  As for the performance evaluation, the images of the image films 4a and 4b on the front and back sides of the light guide plate 11 are visually evaluated, and “○” indicates that the images are not mixed, and the images are not substantially mixed. “△” means that crosses are “x”. Moreover, the front luminance ratio showed the ratio with Comparative Example 1 having the highest front luminance as 1.00. The results are shown in Table 2.

  As shown in Example 1 and Example 2 of the evaluation results in Table 2, the optical performance of the light diffusing members 12 and 12 is such that the reflectance is 55% or more and the light diffusion coefficient is 0.88 or more. Although the front luminance is lower than that of a diffusing member having a high transmittance, it is possible to effectively suppress the reflection of image shadows on other surfaces, and to realize a thin and high-quality double-sided electric signboard 1A. It could be confirmed.

  Among them, the optical performance of the light diffusing members 12 and 12 is such that the reflectance is 78% or more and the light diffusing coefficient of 0.91 or more is particularly effective in reflecting the image shadow on other surfaces. I was able to grasp that it was suppressed.

  On the other hand, when the optical performance of the light diffusing member is a reflectance of 40% and the light diffusing coefficient is 0.88, it is found that the images are mixed and not suitable.

  As a result, it was confirmed that if the reflectance of the light diffusing member is higher than the transmittance of the light diffusing member, the reflection of the image shadow on the other surface can be effectively suppressed.

  The present invention relates to a light source module such as a backlight that emits light from a linearly emitted light source in a planar shape by a light guide member, and a liquid crystal display device such as an electric signboard, a television, and a monitor including the light source module. The present invention can be applied to display devices and electronic devices. In addition, the light source module can be applied as a large planar light source to a display device such as a lighting device and an electronic apparatus.

1A Electric signboard (display device)
1B Illuminated signboard (display device)
1C Illuminated signboard (display device)
2 Cover member 3 Frame 4a Image film (image layer)
4b Image film (image layer)
5 Protection plate 6 Control unit 10A Backlight module (light source module)
10B Backlight module (light source module)
10C backlight module (light source module)
11 Light guide plate (light guide member)
11a Incident surface (end face)
11b Opposing surface 11c Output surface 11d Output surface 11e Side surface 11f Side surface 12 Light diffusing member 13 Light source group 13a Circuit board 13b LED (light source)
14 Light Scattering Section 15 Gap 80 Electric Decoration Sign 82 Light Diffusing Member

Claims (5)

In a light source module comprising a light source and a light guide member that couples light from the light source from the end face, propagates inside, and extracts the outside,
A light diffusing member is disposed on both sides of the light guide member, and
The light source module according to claim 1, wherein the reflectance of each light diffusing member is higher than the transmittance of each light diffusing member.   The light source module according to claim 1, wherein at least one of the light diffusion members is disposed with a gap between the light guide member. An image layer is disposed outside the light diffusion member on the side having a gap between the at least one light diffusion member and the light guide member, and
The light source module according to claim 2, wherein a distance between the light diffusion member and the light guide member is larger than a distance between the image layer and the light diffusion member.   The light source module according to claim 1, wherein the light source is a light emitting diode. A display device comprising the light source module according to any one of claims 1 to 4,
An image layer is disposed on both sides of the light source module.

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