JP4468110B2 - LIGHT EMITTING ELEMENT, LIGHT EMITTING DEVICE HAVING THE SAME, AND DISPLAY DEVICE - Google Patents

Description

  The present invention relates to a light emitting element using a fluorescent action of a fluorescent substance, a light emitting device including the light emitting element, and a display device.

  Conventionally, as an example of a light emitting device using a fluorescent dye, there is one described in Patent Document 1. The light-emitting device described in the document includes a black light and a flat light guide plate that receives ultraviolet light emitted from the black light from one end surface and travels inward. On one surface of the light guide plate, a resin light emitting portion containing an ultraviolet fluorescent dye is provided.

  According to such a configuration, the ultraviolet light that has entered the light guide plate from the black light can be sequentially entered into the light emitting unit while traveling in a certain direction inside the light guide plate. As a result, the fluorescent dye in the light emitting part is excited to fluoresce, and so-called surface emission is realized.

  However, there is room for improvement in the prior art as described below.

  First, since the light emitting unit is provided on one side of the light guide plate, in order for ultraviolet light to enter the light emitting unit, the ultraviolet light in the light guide plate passes through the one side and passes through the one side. It must be emitted outside the light plate. However, the proportion of ultraviolet rays that pass through one side of the light guide plate out of the ultraviolet rays that enter the light guide plate is not so large, and the amount of ultraviolet rays that enter the light emitting portion is small. In particular, when the light emitting part is provided only on a part of one side of the light guide plate, the ultraviolet rays passing through the other part of the one side do not contribute to the light emission of the light emitting part at all. Therefore, in the above prior art, the loss of ultraviolet rays is large and the light emission efficiency is low.

  Second, the amount of ultraviolet light emitted from one side of the light guide plate to the outside is large in a portion near the one end surface of the light guide plate, and decreases as the distance from the one end surface increases. Accordingly, the amount of ultraviolet light that enters the light emitting portion also differs greatly between a portion near the one end face and a portion far from the one end face. In this case, it is difficult to make the light emission intensity of the light emitting portion uniform in various places. For example, as a backlight of a liquid crystal display device, as a requirement for improving the quality of a liquid crystal display image, it is required that there is little unevenness in light emission intensity (luminance) of a surface light emitting portion. It is also difficult to meet the exact demands.

Japanese Patent Laid-Open No. 11-133238

  The present invention has been conceived under such circumstances, and has a light emitting element that has high luminous efficiency and can easily perform uniform light emission intensity of each part of the light emitting part, An object of the present invention is to provide a light-emitting device and a display device including the light-emitting device.

  In order to solve the above problems, the present invention takes the following technical means.

The light emitting element provided by the first aspect of the present invention is formed in a plate shape, and all or a part of the side surface is an incident surface for allowing excitation light to enter , and proceeds from the incident surface to the inside. A light emitting element comprising a light guide that causes the excitation light to travel in a certain direction intersecting the thickness direction, wherein a part of the light guide is made of a fluorescent material that fluoresces when receiving the excitation light. And a light emitting unit that displays a desired pattern at the time of fluorescence, and further includes a plurality of auxiliary members that sandwich the light guide from both sides and have a smaller refractive index than the light guide. Accordingly, the light guide body travels in the fixed direction while totally reflecting the excitation light at the interfaces with the plurality of auxiliary members, and at least a part of the plurality of auxiliary members is made of the light guide body. Light emission It has translucency so that visible light emitted from can be emitted to the outside, and the light emitting portion is configured to be transparent at the time of non-excitation using the resin containing the fluorescent material. On the other hand, a portion other than the light emitting portion of the light guide is formed using the same kind of resin as the resin of the light emitting portion, so that the light emitting portion and the transparent portion whose refractive index is substantially the same. The light emitting portion and the portion other than the light emitting portion are characterized by being in close contact with each other at the boundary portion .

According to the present invention, the excitation light that has entered the light guide enters the light emitting portion as it is in the process of traveling through the light guide, and excites the fluorescent material. Therefore, the amount of excitation light entering the light emitting portion is increased compared to the conventional technique in which the excitation light traveling inside the light guide is made to enter the light emitting portion by being emitted to the outside of the light guide. , Luminous efficiency can be increased. In addition, according to the present invention, since the light emitting unit is caused to emit light by the excitation light traveling in the light guide, excitation light having a sufficient amount of light can be advanced over the entire area of the light emitting unit. In the above prior art, the amount of excitation light emitted from one side of the light guide toward the light emitting part was greatly different between the part close to the light source and the part far from the light source, but the light emission intensity of the light emitting part in the present invention is Excitation light traveling outside the light guide is independent of the amount of excitation light emitted to the outside of the light guide, and does not cause a large bias in the amount of excitation light traveling through the light guide. It is possible to reduce the difference in the amount of light. For this reason, in the present invention, it is possible to easily cause the fluorescent dye in almost the entire area of the light emitting portion to emit light with the peak intensity inherent to the fluorescent dye, and the light emission intensity of each part is uniform over substantially the entire area of the light emitting portion. Can be. When the fluorescent dye is irradiated with excitation light to make it fluorescent, the emission intensity of the fluorescent dye increases as the irradiation amount increases when the irradiation amount of the excitation light is below a certain level, but the irradiation amount of the excitation light reaches a predetermined amount. Then, the light emission amount of the fluorescent dye reaches a certain peak, and even if the amount of excitation light is further increased, the light emission amount of the fluorescent dye does not increase and remains constant. If the peak intensity is set at various points in the light emitting portion, the emission intensity can be made uniform. In addition, according to the above configuration, since the excitation light can be caused to proceed by total reflection in the light guide, the attenuation of the excitation light is suppressed, and the excitation light is more efficiently emitted to various portions of the light emitting unit. Can be advanced. As a result, the luminous efficiency is further increased. Further, according to the above configuration, when the light emitting unit is not emitting light, it is difficult to visually distinguish the light emitting unit from the other remaining portions of the light guide, and the entire light guide is simply transparent with high transparency. It becomes possible to make it look like a board. Therefore, it is possible to display information or decorate information by emitting light from the light emitting unit while using it as a substitute for partition glass or the like that requires high transparency.

  In a preferred embodiment of the present invention, excitation light blocking means for transmitting visible light and blocking excitation light is provided at a position facing the surface of the light guide. According to such a configuration, the excitation light is also prevented from being emitted to the front surface side of the light guide. For example, it is suitable when ultraviolet rays are used as excitation light and used in an environment where the emission of ultraviolet rays is not preferable.

  In a preferred embodiment of the present invention, the light emitting part is provided with first and second light emitting parts that are transparent at the time of non-excitation, and these first and second light emitting parts are provided at the time of excitation. Are configured to emit light in different colors. According to such a configuration, it is possible to perform light emission display or illumination with a plurality of colors, and it is possible to improve the decorativeness.

  In a preferred embodiment of the present invention, the light guide is provided with first and second light guides that are sandwiched between the plurality of auxiliary members and that face each other with a space therebetween. At the same time, the light emitting portions of the first and second light guides are configured so that the light emission colors or light emission patterns at the time of excitation are different from each other. According to such a configuration, two types of light emission display or illumination with different light emission colors or light emission patterns can be performed by one light emitting element.

  In a preferred embodiment of the present invention, light diffusing particles are dispersed and mixed in the light emitting section. According to such a configuration, the light emission luminance of the light emitting portion is enhanced by the action of the visible light emitted from the light emitting portion striking the particles and diffusing. In addition, the uniform emission luminance is promoted. Furthermore, since the excitation light traveling in the light guide is also diffused, for example, when the light guide has a complicated shape, the action of the excitation light traveling over the entire area of the light guide is also promoted.

  The light emitting device provided by the second aspect of the present invention enables the excitation light to be incident on the light emitting element provided by the first aspect of the present invention and the incident surface of the light guide of the light emitting element. And a light source.

  According to such a configuration, the same effect as described for the light emitting element provided by the first aspect of the present invention can be obtained.

The light emitting device provided by the third aspect of the present invention is formed in a plate shape, and all or a part of the side surface is an incident surface for allowing excitation light to enter , and proceeds from the incident surface to the inside. A light guide that travels the excitation light in a certain direction intersecting the thickness direction, and a part of the light guide contains a fluorescent material that fluoresces when receiving the excitation light , and has a desired pattern at the time of fluorescence. The light guide is configured as a light emitting unit to display, and further includes a plurality of auxiliary members sandwiching the light guide from both sides thereof and having a refractive index smaller than that of the light guide. The excitation light travels in the predetermined direction while totally reflecting the excitation light at the interfaces with the plurality of auxiliary members, and at least a part of the plurality of auxiliary members transmits visible light emitted from the light emitting portion of the light guide to the outside. Can emit The light-emitting portion is configured to be transparent at the time of non-excitation using the resin containing the fluorescent material, while the light guide body includes the light-transmitting portion. The portions other than the light emitting portion are formed using the same type of resin as the resin of the light emitting portion, so that the light emitting portion and the transparent portion have substantially the same refractive index, and other than the light emitting portion and the light emitting portion. The portions are in close contact with each other at these boundary portions, and the first and second light guides that are sandwiched between the plurality of auxiliary members and that are opposed to each other with a space therebetween as the light guide. Each of the light emitting portions of the first and second light guides is provided and emits excitation light with a light emitting element configured to have different light emission colors or light emission patterns at the time of excitation. And a light source The obtained excitation light is characterized in that it comprises a switching means to selectively allow the incident to one of each of the incident surface of the first and second light guide body of the light emitting element.

  According to such a configuration, in addition to obtaining the same effect as described for the light emitting element provided by the first aspect of the present invention, each of the first and second light guides can be obtained. The light emitting unit can be switched appropriately to emit light.

  In a preferred embodiment of the present invention, when the light source is turned on and the light emitting portion of the light emitting element emits light, the fluorescent material emits light at a peak intensity in the entire region of the light emitting portion. ing. According to such a configuration, the light emission intensity of the entire region of the light emitting unit is made uniform, which is optimal for applications that require illumination with little uneven illuminance.

  In a preferred embodiment of the present invention, the light emitting element includes a plurality of light emitting elements, and is configured such that excitation light can be incident on an incident surface of a light guide body of each of the plurality of light emitting elements. Yes.

  In a preferred embodiment of the present invention, the plurality of light emitting elements are arranged in a panel shape supported by a support member and arranged on the same plane.

  In a preferred embodiment of the present invention, excitation light incident switching means that allows excitation light to selectively enter each light guide of each of the plurality of light emitting elements is further provided.

  The display device provided by the fourth aspect of the present invention includes the light emitting device provided by the second or third aspect of the present invention.

  According to such a configuration, the same effects as described for the light emitting element and the light emitting device provided by the first to third aspects of the present invention can be obtained.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of a liquid crystal display device. A liquid crystal display device A1 shown in the figure includes a transmissive liquid crystal panel 10 and a light emitting device B1 as a backlight of the liquid crystal panel 10. The light emitting device B1 includes one or more light sources 2 that emit ultraviolet rays and a light emitting element E1. The liquid crystal panel 10 is conventionally known and will not be described in detail.

  The light emitting element E <b> 1 is disposed behind the liquid crystal panel 10. As shown in FIG. 2, the light emitting element E1 includes a flat light guide 3 having a rectangular shape in plan view. The light guide 3 is made of, for example, acrylic resin, polycarbonate, polystyrene, or other resin, and is made of a resin having translucency to visible light and ultraviolet light. However, fluorescent dyes excited by ultraviolet irradiation are dispersed and mixed in the entire area of the light guide 3, and the entire light guide 3 serves as the light emitting unit 4. As the fluorescent dye, for example, a rare earth complex described in JP-A-2003-81986 can be used. The rare earth complexes described in the publication include those capable of emitting red, blue, and green colors, and the fluorescent color can be made white by blending them in a predetermined ratio. In the present embodiment, the light emitting unit 4 is configured to emit white light during fluorescence. In addition, the fluorescent dye can be mixed into the light guide 3 by mixing the fluorescent dye with the molding resin in the molding process of the light guide 3 and performing resin molding.

  Further, light diffusion particles are dispersed and mixed throughout the light guide 3. The particles are, for example, metal particles such as ITO (Indium Tin Oxide), titanium oxide, zinc oxide, or gold (Au), or particles such as alumina. The particle size (average particle size) of the particles is 10 nm to 2000 nm, preferably 50 nm to 1000 nm, more preferably 200 nm to 800 nm. Since the light emitting element E1 is used as a backlight, transparency is not necessary. However, even when transparency is required as described later, the light emitting element E1 is transparent as long as the particle diameter is as described above. In particular, when ITO particles are used, the transparency can be improved.

  The whole or a part of one side surface of the light guide 3 serves as an incident surface 31 for allowing ultraviolet light from the light source 2 to enter. On the other side surface and back surface of the light guide 3, a reflective layer 32 that reflects ultraviolet light and visible light is provided. The reflective layer 32 is, for example, an aluminum vapor deposition film. However, the reflective layer 32 is not limited to such a metal vapor deposition film, and may be configured by using a coating film of another material or attaching a light shielding sheet to the back surface of the light guide 3.

  An ultraviolet blocking layer 33 capable of transmitting visible light is laminated on the surface 30a of the light guide 3. The ultraviolet blocking layer 33 is formed, for example, by adhering a resin sheet containing cerium oxide having an ultraviolet absorbing function, or by applying a resin in which cerium oxide is dispersed and mixed. As shown in the enlarged view of the I part in FIG. 1, the surface 30a of the light guide 3 is formed as a rough surface (non-mirror surface) having a large number of minute irregularities. The roughening process can be performed by laser processing, for example.

For example, an ultraviolet LED is used as the light source 2. However, For example other it is also possible to use a black light using a mercury lamp, as the light emitting means of ultraviolet can be adopted various ones. In the drawing, two light sources 2 are shown. However, the present invention is not limited to this, and a sufficient amount of ultraviolet rays is taken into consideration in consideration of the light emission amount of the light source 2 and the volume of the light guide 3. What is necessary is just to determine the number so that it can supply in the light guide 3. About these points, it is the same also about other embodiment mentioned later. In the present embodiment, the amount of ultraviolet light incident from the light source 2 into the light guide 3 is set to an amount that allows the fluorescent dye to fluoresce with the peak intensity inherent to the fluorescent dye in the entire region of the light emitting unit 4. As shown in phantom lines in FIG. 1, a reflector 34 that reflects ultraviolet rays emitted from the light source 2 toward the incident surface 31 is preferably provided in the peripheral portion of the light source 2. The same applies to the embodiments described later. The light source 2 may be supported by the reflector 34 or other support member, or may be mounted on the incident surface 31 of the light guide 3, and its fixing means is not limited.

  Next, the operation of the light emitting device B1 and the liquid crystal display device A1 including the light emitting device B1 will be described.

  First, when the light source 2 is driven to turn on, ultraviolet rays emitted from the light source 2 enter the light guide 3 from the incident surface 31, and the inside of the light guide 3 intersects the thickness direction of the light guide 3. Proceed in the direction you want. Due to the progress of the ultraviolet rays, each of the fluorescent dyes dispersed and mixed in the entire region of the light guide 3 is excited, and the entire light guide 3 emits white light. Then, the white light passes through the surface 30a of the light guide 3 and the ultraviolet blocking layer 33 and travels toward the liquid crystal panel 10, and the light emitting device B1 appropriately functions as a backlight. A part of the ultraviolet light that has traveled into the light guide 3 reaches the surface 30 a, but is blocked by the ultraviolet blocking layer 33. In order to maintain the quality of each part of the liquid crystal panel 10 over a long period of time, it is preferable not to irradiate the inside with ultraviolet rays, but it is possible to meet such demands accurately.

  As described above, in the light emitting device B1, the fluorescent dye mixed in the light guide 3 is excited in the process in which the ultraviolet rays travel inside the light guide 3. For this reason, the fluorescent dye can be excited efficiently, and the light emission efficiency is increased. In particular, since the back surface of the light guide 3 and the side surfaces other than the incident surface 31 are covered with the reflective layer 32, ultraviolet light incident into the light guide 3 is suppressed from leaking to the outside, and the light guide 3. Most of the ultraviolet light incident on is effectively used for excitation of the fluorescent dye. In addition to this, white light emitted by the fluorescence of the fluorescent dye is also prevented from leaking to the outside through the back and side surfaces of the light guide 3, and the white light emitted from the surface 30a of the light guide 3 is prevented. It is suitable for increasing the amount.

Since the surface 30a of the light guide 3 is roughened, the white light inside the light guide 3 is hardly totally reflected by the surface 30a. This action promotes the action of white light passing from the inside of the light guide 3 through the surface 30a and being emitted toward the liquid crystal panel 10, and is more suitable for increasing the amount of light irradiated to the liquid crystal panel 10. If the surface of the ultraviolet blocking layer 33 is roughened, the white light traveling in the ultraviolet blocking layer 33 can be easily emitted to the outside based on the same principle as when the surface 30a of the light guide 3 is roughened. Can be expected, and such a configuration can also be obtained. In addition, when the refractive index of the light guide 3 and the ultraviolet blocking layer 33 is the same, light is not reflected at the interface between them, and in this case, for example, as shown in FIG. if only the surface 33a of the ultraviolet blocking layer 33 and the roughened, emission of white light Ru promoted.

  In the light emitting device B1, since the fluorescent dye is configured to fluoresce in the entire region of the light emitting unit 4 with a peak intensity unique to the fluorescent dye, the light emission intensity of each part of the light emitting unit 4 is uniformly aligned. . The light emitting unit 4 is formed to be slightly larger than the image display area of the liquid crystal panel 10 and faces the image display area. Accordingly, the white light traveling from the light emitting unit 4 toward the image display area has very little variation in the amount of light, and the quality of the image displayed on the liquid crystal panel 10 can be improved. On the other hand, in the light emitting device B1, as described above, the ultraviolet light incident in the light guide 3 efficiently excites the fluorescent dye in the light guide 3, and the waste of ultraviolet light is small. Therefore, the light emission amount of the light source 2 required to cause the fluorescent dye to fluoresce with the peak intensity in the entire region of the light emitting unit 4 is relatively small, and the power consumption can be reduced. The light diffusing particles mixed in the light guide 3 act to scatter and reflect the light generated in the light guide 3 in various directions to increase the amount of white light emitted from the surface 30a. In addition to this, an effect of further reducing variations in the amount of emitted light at various locations on the surface 30a is also produced.

4 to 22 show other embodiments. In these drawings, the same or similar elements as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment.

  In the light emitting device B2 shown in FIG. 4, a transparent ultraviolet blocking layer 33A is provided on the back surface of the light guide 3 constituting the light emitting element E2. Unlike the light emitting element E1 described above, the light emitting element E2 is not provided with the reflective layer 32 on the back surface of the light guide 3, and each of the light guide 3 and the pair of ultraviolet blocking layers 33 and 33A is provided. Is transparent, the entire light emitting element E2 is transparent enough to transmit visible light. The light emitting element E2 may be semitransparent.

  According to the light-emitting device B2, when the light source 2 is driven to be lit, it can be used as a surface-emitting illumination device that emits light from substantially the entire light guide 3 as in the above embodiment. is there. However, when the light source 2 is not turned on, the entire light emitting element E2 is transparent, and can be used for the following applications, for example.

  FIG. 5 shows an example in which a lighting window A2 for a house is configured using the above-described light emitting device B2. As shown in FIG. 6, the window A <b> 2 has a configuration in which the light emitting element E <b> 2 and the light source 2 are mounted on a rectangular frame 60 attached and fixed to the wall of the house. According to this window A2, in the daytime, outdoor light is allowed to pass through the light emitting element E2 and enter indoors, thereby allowing daylighting. On the other hand, at night, the light source 2 is driven to turn on and the light emitting element E2 emits light, so that it can be used as an indoor lighting device. Since surface light emission is performed over a wide area of the window A2, illumination with rich taste is performed. If the fluorescent dye mixed in the light guide 3 emits colored light at the time of excitation, the preference can be further enhanced. In addition, since the light emitting element E2 has an excellent ultraviolet blocking function, an effect of preventing ultraviolet rays of sunlight from entering the room during the daytime when the sunlight is strong can be obtained.

  In FIG. 7, a window frame 61 includes partition members (crosspieces) 61a extending vertically and horizontally, and a plurality of (for example, four) light emitting elements E2 are partitioned by these partition members 61a. 61 is attached. A plurality of light sources 2 are also attached to the frame 61 in correspondence with the plurality of light emitting elements E2. According to such a structure, there exists an advantage which can enlarge the size of the whole window, without enlarging each size of the several light emission element E2 so much. Further, if the fluorescent colors of the respective fluorescent dyes of the plurality of light emitting elements E2 are made different, when the plurality of light emitting elements E2 are caused to emit light, illumination using a plurality of colored lights becomes possible, and the preference is further increased. Will increase.

  FIG. 8 shows an example in which the table A3 is configured using a plurality of light emitting devices B2. In the table A3, the top plate 62 has translucency, and a plurality of light emitting elements E2 and light sources 2 constituting the plurality of light emitting devices B2 are provided on the lower surface side of the top plate 62. According to such a configuration, by causing each light emitting element E2 to emit light, it is possible to illuminate the top plate 62 with the color light of the fluorescent color of each light emitting element E2. Moreover, the lower part of the top plate 62 can also be illuminated. Therefore, there is an appealing aspect of lighting, which is suitable as a table for a store such as a restaurant.

  Preferably, the plurality of light emitting devices B2 in the table A3 are configured such that the light sources 2 can be turned on and off independently of each other, and include a switch or the like. According to such a configuration, for example, when four persons are seated around the table A3, the four light emitting elements E2 are caused to emit light, whereas when two persons are seated, only the corresponding two light emitting elements E2 are allowed to emit light. It will be possible to make it more interesting.

As can be understood from the embodiment shown in FIGS. 7 and 8 , a plurality of light emitting elements E2 may be arranged and light may be emitted by switching them all at once or part by part. Of course, the same applies to the light emitting element E1 of the embodiment described above and other light emitting elements described later.

  In the configuration shown in FIG. 9, one light source 2 and a plurality of light emitting elements E2 are optically connected through optical fibers 63a and 63b and a switching device 64 such as an optical cross connect switch. An optical fiber 63a that receives ultraviolet light from the light source 2 is connected to the input port of the switching device 64, and a plurality of optical fibers for allowing ultraviolet light to enter each of the plurality of light emitting elements E2 to the plurality of output ports. 63b is connected. According to such a configuration, by switching the switching device 64, the ultraviolet rays emitted from the light source 2 are selectively incident on only one of the plurality of light emitting elements E2, and the plurality of light emitting elements E2 are used. It becomes possible to make ultraviolet rays incident on all of them simultaneously. Therefore, in addition to the fact that the total number of light sources 2 can be reduced, there is an advantage that the configuration for selecting a plurality of light emitting elements E2 to emit light can be simplified.

  As understood from the embodiment shown in FIG. 9, in the present invention, when ultraviolet light is incident on the light guide of the light emitting element, the light source is not necessarily provided near the entrance surface of the light guide. Good. In addition to the optical fiber, it is possible to adopt a configuration in which ultraviolet rays are incident on the incident surface of the light guide using light guide means such as a mirror or a prism.

  In the light emitting device B3 shown in FIG. 10, the light guide 3 constituting the light emitting element E3 is formed in a bar shape extending in a certain direction. The light guide 3 has a rectangular cross-sectional shape and is uniform in the longitudinal direction of the light guide 3. An end surface of one end portion in the longitudinal direction of the light guide 3 is an incident surface 31 on which ultraviolet light is incident from the light source 2. Regarding the point that the entirety of the light guide 3 is the light emitting part 4 containing a fluorescent dye, and the point that the light guide 3 is provided with the reflective layer 32 and the ultraviolet blocking layer 33, the light emitting device described above. The same as the light emitting element E1 of B1.

  In the light emitting device B3, when the light source 2 is driven to be turned on and ultraviolet rays are incident on the light guide 3, the ultraviolet rays proceed toward the longitudinal direction of the light guide 3. In the process of progress, the fluorescent dye in the light guide 3 is excited, and visible light generated by the excitation passes through the ultraviolet blocking layer 33 from the surface 30a of the light guide 3 and is emitted to the outside. Since the surface 30a of the light guide 3 is an elongated rectangular region, the light emitting device B3 can illuminate the line-shaped region.

  FIG. 11 shows an example in which the image reading device A4 is configured using the light emitting device B3. In this image reading apparatus A4, the surface 30a of the light guide 3 that emits light from the light emitting element E3 and the ultraviolet blocking layer 33 are directed to the document 65, and the progress of light reflected after the document 65 is irradiated. A lens array 66 for imaging and a light receiving element 67 for imaging are provided on the path. In this image reading apparatus A4, while conveying the document 65 in the sub-scanning direction, light is emitted from the light emitting element E3 to the document 65 in a line shape, and the reflected light is sequentially received by the light receiving element 67 for each line. By reading, an image of a planar area can be read, and can be applied to a facsimile apparatus and various scanner apparatuses. In such an image reading process, in order to obtain a high-quality read image, it is required to make the illuminance of the entire line-shaped reading area of the document 65 uniform. On the other hand, in the light-emitting device B3, as described in the light-emitting device B1, the fluorescent dye in each part of the light-emitting unit 4 is made to fluoresce at a predetermined peak intensity, so that the light-emitting device B3 can The amount of emitted visible light can be made uniform. Therefore, if the total length of the light emitting unit 4 is set to be larger than the maximum reading width of the image reading apparatus A4 (the maximum width of the document 65), the above request can be met accurately.

  In the configuration shown in FIG. 12, the width of the front surface 30a of the light guide 3 and the ultraviolet blocking layer 33 of the light emitting element E3 is made narrower than the width of the back surface of the light guide 3. Such a configuration is suitable for reducing the width of visible light traveling from the surface 30 a and the ultraviolet blocking layer 33 toward the document 65 and increasing the illuminance of the image reading target area of the document 45. As understood from the present embodiment, when the light guide is formed in a bar shape, the cross-sectional shape can be a shape other than the long rectangle.

  In the light emitting device B4 shown in FIG. 13, the light emitting element E4 includes a flat light guide 3A and two flat auxiliary members 5A and 5B sandwiching the light guide 3A from both sides in the thickness direction. It is set as the structure provided. The auxiliary members 5A and 5B are both transparent, the refractive index thereof is smaller than the refractive index of the light guide 3A, and the surfaces of the light guide 3A with respect to the front surface and the back surface are mirror surfaces. Closely against. As a result, the interface between the light guide 3A and each of the two auxiliary members 5A and 5B causes the ultraviolet light traveling in the light guide 3A to be incident when the ultraviolet light is incident at a larger angle than the total reflection critical angle. It is a totally reflective surface. Preferably, an ultraviolet blocking layer 33 is provided on the outer surfaces of the auxiliary members 5A and 5B. In the embodiment shown in FIG. 1, when the ultraviolet blocking layer 33 is laminated on the surface 30 a of the light guide 3, the surface 30 a or the ultraviolet blocking is used as a means for easily emitting the light in the light guide 3 to the outside. Although the means for roughening the surface of the layer 33 has been described, the same means can be adopted when the ultraviolet blocking layer 33 is laminated on the auxiliary members 5A and 5B.

  Unlike the light guide 3 described above, the light guide 3A is a light emitting portion 4A (a portion with a halftone dot pattern in FIG. 13) containing a transparent fluorescent dye. The other part is a non-light emitting part 49 that does not contain a fluorescent dye. For example, as illustrated in FIG. 15A, the light emitting unit 4 </ b> A is formed in a form that displays a pattern such as a character “ABC”. The light emitting portion 4A and the non-light emitting portion 49 are both transparent, and the same type of resin is used as their main component, and their refractive indexes are substantially the same. Further, the boundary portions thereof are in close contact with each other.

  In order to manufacture the light emitting element E4, for example, as shown in FIG. 14, the light emitting portion 4A is formed on the auxiliary member 5B by a printing technique. This printing may be performed using a paint in which a fluorescent resin is mixed as a pigment in a desired resin dissolved in a solvent. Further, a non-light emitting portion 49 is formed on the remaining portion on the auxiliary member 5B by applying a resin that is the same type of resin as that used in the paint and not mixed with a fluorescent dye. This application may be printing, but may be spin coating or the like. In the case of spin coating, the non-light emitting portion 49 may be laminated on the light emitting portion 4A, but such a configuration may be used. This is because even in this case, the ultraviolet rays can be appropriately passed through the light emitting portion 4A. After forming the light emitting part 4 and the non-light emitting part 49, the auxiliary member 5A may be laminated on them. Since the auxiliary member 5B has a certain degree of mechanical strength, and if the necessary strength is ensured for the entire light emitting element E4, it is not necessary to increase the mechanical strength of the auxiliary member 5A. In such a case, the auxiliary member 5A may be formed by a printing method. The auxiliary members 5A and 5B need not have the same thickness.

  In the light emitting device B4 of this embodiment, when ultraviolet rays emitted from the light source 2 enter the light guide 3A, the ultraviolet rays are guided while being totally reflected at the interface between the light guide 3A and the auxiliary members 5A and 5B. Proceed through the body 3A. Accordingly, since the attenuation of ultraviolet rays is small and a large amount of ultraviolet rays can be efficiently guided to the light emitting unit 4A, the light emitting unit 4A can appropriately emit light while reducing the output of the light source 2. Visible light generated by fluorescence in the light emitting portion 4A passes through the auxiliary members 5A and 5B and is emitted to the outside, and is clearly recognized, for example, as shown in FIG. On the other hand, when the light source 2 is not driven, both the light emitting portion 4A and the non-light emitting portion 49 are made of a transparent material having substantially the same refractive index, so that light is largely refracted at the boundary portion between them. There is nothing, and it is difficult to visually confirm the boundary portion. Therefore, the light emitting element E4 can be recognized as a non-patterned transparent plate. As a result, when the light emitting portion 4A is caused to emit light, the viewer is given a feeling that a pattern such as a character displayed by the light emitting portion 4A suddenly appears from a transparent area where nothing exists.

  FIG. 16 shows an example in which an exhibition window A5 that is frequently used in a museum or the like is configured using the above-described light emitting device B4. In the display window A5, as shown in FIG. 4B, the light emitting element E4 and the light source 2 are mounted on a frame body 68 arranged on the peripheral portion of the display window A5, and the light emitting element E4 functions as a partition glass. Plays. According to the display window A5, during the normal time when the light emitting element E4 does not emit light, the entire light emitting element E4 can be kept in a highly transparent state. Can not be. On the other hand, when the light emitting portion 4A of the light emitting element E4 is caused to emit light, as shown in FIG. 17, for example, information regarding the exhibit 69 can be displayed and recognized by the visitor by the light emitting portion 4A.

  FIG. 18 shows an example in which a signboard device A6 for shops is configured using the light emitting device B4. In this signboard device A6, a light emitting element E4 is placed on the front face of a signboard body plate 70 whose name is painted on the surface. The light emitting element E4 is supported using an appropriate support member such as the frame 71, and the light source 2 is supported in the same manner. In this signboard device A6, for example, the light emitting portion 4A of the light emitting element E4 is not lighted during the daytime. In this state, it is possible to clearly see characters such as store names and other patterns displayed on the surface of the signboard body plate 70 through the light emitting element E4. On the other hand, at night, the light emitting portion A4 of the light emitting element E4 is caused to emit light. Then, a design with a design different from that of the signboard body plate 70 is displayed in a light-emitting manner, and an attractive advertising effect is obtained.

  The light emitting device B5 shown in FIG. 19 has a configuration in which two types of light emitting portions 4A and 4B are provided on the light guide 3A of the light emitting element E5. These light emitting portions 4A and 4B have substantially the same refractive index and contain transparent fluorescent dyes, but these fluorescent dyes are different in fluorescent color at the time of excitation. . This light-emitting device B5 is a fluorescent light-emitting device B4 described with reference to FIG. 14 in place of the step of forming a non-light-emitting portion 49 by applying a resin containing no fluorescent dye on the auxiliary member 5B. It can manufacture by apply | coating resin containing a pigment | dye.

  In this light emitting device B5, when the light source 2 is not lit, it is difficult to visually recognize the light emitting portions 4A and 4B and their boundaries, and the light emitting element E5 can be recognized as a simple transparent plate. it can. On the other hand, when the light source 2 is turned on and the light emitting units 4A and 4B emit light, for example, as shown in FIG. 19 (b), the light emitting unit 4A emits and displays predetermined characters and the background portion emits light. It is possible to emit light with a color different from that of the light emitting unit 4A by the light emission of the unit 4B.

  As can be understood from the present embodiment, the present invention can be configured to include a plurality of types of light emitting units having different colors during light emission. In this way, it is possible to display a variety of colors, and it is also possible to use as a lighting device that emits a large amount of light by emitting information on characters and the like while emitting light on the background portion. Needless to say, the light emitting device B5 can be used for the applications shown in FIGS.

  In the light emitting device B6 shown in FIG. 20, the auxiliary member 5B ′ of the light emitting element E6 is opaque. According to such a configuration, the visible light from the light emitting portion 4 does not pass through the auxiliary member 5B ′ and exit to the outside, but passes through the auxiliary member 5A and exits to the front (upward in the drawing). Therefore, the luminance of the light emitting unit 4A in the front direction can be increased. Such a light emitting device B6 is suitable for an application in which it is sufficient to perform a desired display only in the front direction of the light emitting element E6. Moreover, a pattern such as letters and symbols can be attached to the auxiliary member 5B ′, and the pattern can be seen through the auxiliary member 5A and the light guide 3A from the front side of the auxiliary member 5A.

  In the light emitting device B7 shown in FIG. 21, the light emitting element E7 includes three plate-like auxiliary members 5A to 5C and two light guides 3C and 3D sandwiched between them. . All or part of the light guides 3C and 3D are formed as transparent light emitting portions 4C and 4D when not excited. The light emitting portions 4C and 4D are different in emission color or pattern at the time of excitation. Each of the auxiliary members 5A to 5C has a refractive index smaller than that of the light guides 3C and 3D, and the contact surface with the light guides 3C and 3D can totally reflect the ultraviolet rays traveling through the light guides 3C and 3D. It is an interface. The auxiliary members 5A and 5B are at least transparent. As can be understood from the embodiment shown in FIG. 19, the auxiliary member 5C may be either transparent or opaque. When the light emission display is also performed on the back side (the auxiliary member 5C side) of the light emitting element E7, the auxiliary member 5C may be transparent, and otherwise, the auxiliary member 5C may be opaque. The plurality of light sources 2C and 2D are provided so that ultraviolet rays can be individually incident on the two light guides 3C and 3D.

  According to the light emitting device B7, the ultraviolet light incident into the two light guides 3C and 3D can be caused to travel to the light emitting units 4C and 4D while being totally reflected, and the light emitting units 4C and 4D can emit light efficiently. . When the on / off of the light sources 2C and 2D is controlled and only the light source 2C is driven to be lit, the light emitting unit 4C can emit light in a manner as shown in FIG. 22A, for example. On the other hand, when the light source 2D is driven to be turned on instead of the light source 2C, the light emitting unit 4C can emit light in a mode as shown in FIG. Thus, in the light emitting device B7, two types of light emitting displays having different patterns or colors can be switched and displayed by turning on and off the light sources 2C and 2D.

  In the light emitting device B7, a plurality of light sources 2C and 2D are provided corresponding to the two light guides 3C and 3D, but the present invention is not limited to this. For example, as in the embodiment shown in FIG. 9, ultraviolet light emitted from one or more light sources is guided to two light guides 3C and 3D using an optical fiber or a switching device, and the light is guided by control of the switching device. You may enable it to switch incidence | injection of the ultraviolet-ray to the bodies 3C and 3D. Further, a light guide body and auxiliary members may be further added and laminated, and the light guide body may be configured to have a multilayer structure of three layers or more so that more light emitting units are switched and displayed. Furthermore, in the present invention, instead of the configuration in which the two light guides 3C and 3D are sandwiched between the three auxiliary members 5A to 5C as in the light emitting device B7, for example, for light emission as shown in FIGS. Even when a plurality of elements E4 and E5 are arranged in a stacked manner and the respective light emitting portions of the plurality of light emitting elements are switched to emit light, the same operation as the above light emitting device B7 can be obtained. However, from the viewpoint of reducing the number of auxiliary members and reducing the overall thickness, the light guide device B7 has a structure in which two light guides 3C and 3D are laminated on both sides of one auxiliary member 5B. It is preferable to do.

  The present invention is not limited to the embodiment described above. The specific configuration of each part of the light emitting element, the light emitting device, and the display device according to the present invention can be varied in design in various ways.

For example, it the overall shape of the overall shape or the light guide of the light emitting element, a circular, oval, triangular, trapezoidal, star-shaped, also be formed in a plate shape such as a heart-shaped. In addition, the plate shape referred to in the present invention does not particularly ask for the thickness. Accordingly, a sheet-like one having a small thickness is also included in the plate-like concept.

In the present invention, the specific types and components of the fluorescent dye are not particularly limited. Moreover, as excitation light, it is also possible to use light outside the ultraviolet region, for example, using visible light in the near ultraviolet region. The light source for generating excitation light, as described above, also including the specific types and numbers have such limited.

The light-emitting element and light-emitting device according to the present invention can be used as various illumination devices and display devices or as components thereof in addition to the above -described uses, and the specific uses are not limited. It can also be used as a sign, interior, accessory, figurine, or a component thereof.

It is a cross-sectional view showing an example of a light emission device and a liquid crystal display device having the same. It is a partially broken perspective view of the element for light emission of the light-emitting device shown in FIG. It is a principal part enlarged view which shows the element for light emission of the light-emitting device shown in FIG. It is a cross-sectional view showing another example of the light emission device. It is a principal part perspective view which shows an example of the window comprised using the light-emitting device shown in FIG. (A) is a front view which shows the component of the window shown in FIG. 5, (b) is VI-VI sectional drawing of (a). (A) is a front view which shows an example of the structural component of the window comprised using multiple light-emitting devices shown in FIG. 4, (b) is VII-VII sectional drawing of (a). (A) is a perspective view which shows an example of the table comprised using multiple light-emitting devices shown in FIG. 4, (b) is VIII-VIII sectional drawing of (a). It is explanatory drawing which shows typically an example in the case of making an ultraviolet light inject into a several light guide. (A) is a sectional view showing another example of a light emission device, (b) is its partially broken perspective view. It is explanatory drawing which shows an example of the image reading apparatus comprised using the light-emitting device shown in FIG. It is explanatory drawing which shows the other example of the image reading apparatus comprised using the light-emitting device shown in FIG. It is sectional drawing which shows an example of the light-emitting device which concerns on this invention. It is sectional drawing which shows an example of the manufacturing process of the element for light emission of the light-emitting device shown in FIG. (A), (b) is explanatory drawing which shows an example of the non-light-emission state and light emission state of the light emission part of the light-emitting device shown in FIG. (A) is a principal part perspective view which shows an example of the display window comprised using the light-emitting device shown in FIG. 13, (b) is XVI-XVI sectional drawing of (a). It is a principal part perspective view which shows an example at the time of making the light emission part of the display window shown in FIG. 16 light-emit. (A) is a principal part perspective view which shows an example of the signboard apparatus comprised using the light-emitting device shown in FIG. 13, (b) is XVIII-XVIII sectional drawing of (a). (A) is sectional drawing which shows the other example of the light-emitting device based on this invention, (b) is explanatory drawing which shows an example of the state at the time of the light emission. It is sectional drawing which shows the other example of the light-emitting device which concerns on this invention. It is sectional drawing which shows the other example of the light-emitting device which concerns on this invention. (A), (b) is explanatory drawing which shows an example of the state which switched and light-emitted two light emission parts of the light-emitting device shown in FIG.

Explanation of symbols

A1 liquid crystal display device A2 window A3 table A4 image reading device A5 exhibition window A6 signboard device B1 to B7 light emitting device E1 to E7 light emitting element 2, 2C, 2D light source 3, 3A, 3C, 3D light guide 4, 4A to 4D Light emitting part 5A-5C Auxiliary member 10 Liquid crystal panel 31 Incident surface 32 Reflective layer 33 UV blocking layer

Claims (10)

A light guide that is formed in a plate shape and has all or part of the side surface as an incident surface on which excitation light is incident, and the excitation light traveling inward from the incident surface proceeds in a certain direction intersecting the thickness direction. A light emitting element comprising a body,
A part of the light guide includes a fluorescent material that fluoresces when receiving the excitation light , and is configured as a light emitting unit that displays a desired pattern at the time of fluorescence,
The light guide is sandwiched from both sides and further provided with a plurality of auxiliary members having a refractive index smaller than that of the light guide, so that the light guide is excited at the interface with the plurality of auxiliary members. While traveling in the predetermined direction while totally reflecting light, at least a part of the plurality of auxiliary members has translucency so that visible light emitted from the light emitting part of the light guide can be emitted to the outside. Have
While the light emitting portion is configured to be transparent at the time of non-excitation using a resin containing the fluorescent material,
Of the light guide, the part other than the light emitting part is formed using the same type of resin as the resin of the light emitting part, so that the light emitting part and the transparent part have substantially the same refractive index. The light emitting element, wherein the light emitting portion and the portion other than the light emitting portion are in close contact with each other at the boundary portion . The first and second light emitting units are provided as the light emitting units, and the first and second light emitting units are configured to emit light in different colors at the time of excitation. The light emitting element according to 1. As the light guide, there are provided first and second light guides that are sandwiched between the plurality of auxiliary members and are opposed to each other with a gap therebetween,
The respective light emitting portion of the first and second lightguide emission color or luminous patterns upon excitation is configured different from each other, the light emitting element according to claim 1 or 2. The light emitting element according to claim 1, wherein light diffusing particles are dispersed and mixed in the light emitting portion. 5. A light emitting device comprising: the light emitting element according to claim 1; and a light source capable of making excitation light incident on an incident surface of a light guide of the light emitting element. . The light emitting element according to claim 3, a light source that emits excitation light, and excitation light emitted from the light source is selected as one of the incident surfaces of the first and second light guides of the light emitting element. And a switching means that allows the incident light to enter the light emitting device . The light emitting element includes a plurality of light emitting elements, and configured to allow excitation light to be incident on an incident surface of a light guide body of each of the plurality of light emitting elements. Light emitting device . The light emitting device according to claim 7, wherein the plurality of light emitting elements are arranged in a panel shape supported by a support member and arranged on the same plane . The light emitting device according to claim 7, further comprising excitation light incident switching means that allows excitation light to selectively enter each light guide of the plurality of light emitting elements . A display device comprising the light-emitting device according to claim 5.

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