JP2010062135A - Light source module, method for manufacturing the same, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source module that is thin type and has high uniformity in chromaticity and brightness. <P>SOLUTION: The light source module includes: a light guide 2; a light source 1 that is optically connected with an end surface 2e of the light guide 2 and emits light with a specific color toward an inside of the light guide 2; and a first light path conversion layer 30 that is provided on one main surface 2b of the light guide 2 and contains a material for wavelength-converting the light emitted from the light source 1. The first light path conversion layer 30 has one or a plurality of pattern elements 3a arranged along the main surface 2b. A dimension of the pattern elements 3a in a vertical direction Y with respect to a light guide direction X of the light emitted from the light source 1 is shorter than that of the pattern elements 3a in the light guide direction X. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light source module, and more particularly to a light source module that emits light from a main surface (light emitting surface other than an end surface) of a light guide. This type of light source module is used as a general illumination device or a backlight of a liquid crystal display device.

  Moreover, this invention relates to the manufacturing method of the light source module which produces such a light source module.

  Moreover, this invention relates to the electronic device provided with such a light source module.

  A general surface light source module includes a light guide plate and a white LED light source coupled to an end face of the light guide plate, guides white light emitted from the white LED light source into the light guide plate, White light is emitted from one main surface other than the end face. The white LED light source is usually configured by housing a blue LED chip in a package and filling a phosphor material so as to surround the blue LED chip. Yellow (or red and green) fluorescence emitted when the phosphor is excited by a part of the blue light emitted from the blue LED chip and the remaining part of the blue light are mixed into white light. A fine prism (groove) or the like for directing light introduced into the light guide plate to the light output surface is provided on the surface opposite to the light output surface of the light guide plate.

Japanese Patent No. 2868885

  The general surface light source module has the following problems i) to vi).

  i) The phosphor material constituting the white LED light source may be irradiated with excitation light for a long time, resulting in a decrease in wavelength conversion efficiency or discoloration. Particularly, in the vicinity of the blue LED chip, the irradiation energy per unit area of the excitation light is strong, so that the deterioration of the phosphor material is promoted.

  ii) The package of the white LED light source is larger by the phosphor than the size of the blue LED chip itself. As a result, when the entire light emitting surface of the white LED light source is coupled to the end surface of the light guide plate in order to guide a large amount of light from the white LED light source into the light guide plate, the thickness of the light guide plate is increased. This increases the size and weight of the module.

  iii) When the thickness of the light guide plate is increased, the cost of the member related to the light guide plate increases.

  iv) The chromaticity of the light emitted from the package varies depending on the amount of the phosphor contained in the package of the white LED light source, and the chromaticity of the light emitted from the light guide plate varies. As a countermeasure, it takes time and effort to sort out a plurality of white LEDs having close chromaticity.

  v) The amount of the phosphor used is large and the material cost is high.

  vi) When the light guide plate is manufactured, since the fine prism or the like is usually formed using a mold, the manufacturing cost for the light guide plate is high. In particular, when a mold having the same size as that of the light guide plate is manufactured to increase the area, the cost is further increased. When a large number of small light guide plates are coupled to increase the area, the luminance uniformity of the coupled portion is lowered.

  Recently, in order to solve these problems i) to vi), Patent Document 1 (Japanese Patent No. 2868085) discloses a light guide plate and blue light emission optically connected to an end face of the light guide plate. A method including a diode (hereinafter referred to as “blue LED”) has been proposed. A fluorescent scattering layer is provided on any one of the main surfaces of the light guide plate. The fluorescent scattering layer is applied in a state where a fluorescent material that emits fluorescence when excited by the light emission of the blue LED and a white powder that scatters fluorescence are mixed. ing. A part of the blue light emitted from the blue light emitting diode is wavelength-converted in the fluorescence scattering layer, and the light generated by the wavelength conversion and the remaining part of the blue light are mixed together, so that the opposite side of the fluorescence scattering layer is mixed. The light is emitted as white light from the main surface (light emitting surface) of the light guide plate.

  In this document, the fluorescent scattering layer is formed in a dot shape, and the density per unit area of the dots is set as a specific pattern to achieve uniform surface luminance on the light emitting surface side (the fluorescent scattering layer is the light guide plate). ), The luminance is high in the vicinity of the blue LED, and the luminance decreases as the distance from the blue LED increases.

  However, in the method of the same document, when the blue light from the blue LED travels inside the light guide plate, the intensity of the blue light drops sharply, and the luminance uniformity on the light exit surface is insufficient. There is a problem of becoming. Further, when the blue light from the blue LED travels inside the light guide plate, depending on the position in the light guide plate, the intensity of the blue light traveling and the light scattered (wavelength converted) by the fluorescence scattering layer The ratio with the intensity of the light is not always constant and changes. For this reason, there exists a problem that the chromaticity of the light radiate | emitted from a light-projection surface changes according to the position in the said light-guide plate.

  In addition, inside the package in which the conventional LED is arranged, the light emitted from the LED (blue light) and the light emitted from the phosphor cause multiple reflection in the package and color mixing occurs. Although the light reflectance in the package depends on the resin optical characteristics used in the package, it is considered to be, for example, about 90% at the highest, and a loss of 10% of light occurs every time reflection occurs. Therefore, as multiple reflections are repeated in the package, the amount of light extracted from the LED package decreases, and the light extraction efficiency decreases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a light source module that can emit light that is thin and has high chromaticity and luminance uniformity.

  Moreover, the subject of this invention is providing the manufacturing method of the light source module which produces such a light source module.

  Moreover, the subject of this invention is providing the electronic device provided with such a light source module.

In order to solve the above problems, the light source module of the present invention is:
A light guide that transmits light;
A light source that is optically connected to at least one of the end faces of the light guide and emits light of a specific color toward the inside of the light guide;
A first optical path conversion layer that is provided on one main surface perpendicular to the end face of the light guide and includes a material that converts the wavelength of the light from the light source;
The first optical path conversion layer has one or a plurality of pattern elements arranged along the one main surface, and the first optical path conversion layer has a size greater than the dimension of the pattern element with respect to a light guide direction of the light from the light source. The dimension of the pattern element in a direction perpendicular to the light guide direction is short.

  As used herein, the phrase “comprising a material” refers to including a material in a substantially uniform distribution throughout the layer, rather than locally in a portion of the layer.

  “Intrinsic color light” refers to light exhibiting a specific hue other than white.

  The “light guide direction” of the light refers to the main traveling direction of the light excluding scattered light and the like inside the light guide.

  In the light source module of the present invention, a part of the light of the intrinsic color from the light source introduced into the light guide is incident on the first optical path conversion layer, and the wavelength is converted by the first optical path conversion layer. Scattered. Then, the wavelength-converted light and the remaining part of the intrinsic color light from the light source are mixed inside the light guide. The mixed light is emitted to the outside from the other main surface (light emitting surface) opposite to the one main surface of the light guide.

  Here, as the light source that emits the light of the intrinsic color, a light source that does not contain a phosphor material, such as a simple blue LED, can be employed. In such a case, the problems i) to vi) related to the white LED light source described above can be solved as follows.

  i ′) According to the present invention, the light source and the first optical path conversion layer (a material that converts the wavelength of light from the light source, typically a layer containing a phosphor substance) are disposed separately. Therefore, the irradiation energy per unit area of light from the light source becomes relatively weak at the position of the first optical path conversion layer, and the deterioration of the first optical path conversion layer (phosphor material constituting the first optical path conversion layer) can be prevented. it can.

  ii ′) According to the present invention, a light source that does not contain a phosphor material can be adopted, so that the size of the light source can be made substantially equal to the size of the LED chip, and the size of the light exit surface of the light source can be reduced. Accordingly, the thickness of the light guide (typically, the light guide plate) can be reduced. Therefore, the light source module can be reduced in thickness and weight.

  iii ′) According to the present invention, since the thickness of the light guide can be reduced, the member cost related to the light guide can be reduced. Further, the cost can be further reduced by reducing the amount of phosphor used.

  iv ′) According to the present invention, a light source that does not contain a phosphor material can be adopted as the light source, so that variations in chromaticity of light emitted from individual LEDs do not occur. Further, the first optical path conversion layer can be formed to have a uniform thickness by, for example, printing. In such a case, variation in chromaticity due to the first optical path conversion layer is easily suppressed. Therefore, the chromaticity of the light emitted from the light guide becomes uniform.

  v ′) According to the present invention, as described above, the first optical path conversion layer can be formed thin to a uniform thickness, for example, by printing (inside the light guide, the light is guided from the light source). Along with the fact that the optical distance can be made relatively long (described later). In such a case, the amount of phosphor used can be reduced.

  vi ′) According to the present invention, the first optical path conversion layer (and the second optical path conversion layer described later) can be easily formed at low cost on one main surface of the light guide, for example, by printing. Further, it is not necessary to perform fine processing (molding of a prism or the like) on the light guide using a mold. Thus, costs associated with the light guide are reduced.

  In the light source module of the present invention, the first optical path conversion layer includes a plurality of pattern elements arranged along the one main surface, and the dimension of the pattern element with respect to the light guide direction of the light from the light source. The dimension of the pattern element in the direction perpendicular to the light guide direction is shorter than Therefore, the problem which the system of patent document 1 produces can be solved. That is, in the light source module according to the present invention, the light from the light source is not scattered through the gap between the pattern elements arranged in the direction perpendicular to the light guide direction inside the light guide, and the light guide direction. Proceed to. Therefore, the light guide distance of the light from the light source can be made relatively long. Thereby, the uniformity of chromaticity and luminance of light emitted from the light emitting surface of the light guide is increased.

  Moreover, in this invention, the light radiate | emitted from the light source (for example, LED) advances by totally reflecting within a light guide. Since the light guide is a light guide member that transmits light, the member itself absorbs little light, and since the light is guided by totally reflecting the inside, there is almost no loss of light amount due to reflection. Therefore, the ratio of light that can be used in the light source module out of the light emitted from the light source is high, and a light source module with high light use efficiency can be manufactured.

  In the light source module according to one embodiment, the distribution density of the first optical path conversion layer increases as the distance from the end face of the light guide increases.

  The first optical path conversion layer wavelength-converts and scatters the light from the light source incident on the first optical path conversion layer. Here, in the light source module of this embodiment, the distribution density of the first optical path conversion layer increases as the distance from the end face of the light guide increases. Thereby, the probability that the light from the light source is wavelength-converted and scattered as the distance from the end face of the light guide increases. Therefore, even if the intrinsic color light traveling in the light guide direction in the light guide decreases as it moves away from the end face of the light guide, it is emitted from the light exit surface of the light guide. The decrease in the brightness of the light is suppressed. As a result, the luminance uniformity is further increased.

  In the light source module according to the embodiment, the pattern element of the first optical path conversion layer is inclined at a gradually increasing inclination angle with respect to a light guide direction of the light from the light source as it moves away from the end face of the light guide. It is characterized by that.

  As described above, the first optical path conversion layer wavelength-converts and scatters the light from the light source incident on the first optical path conversion layer. Here, in the light source module of this one embodiment, the pattern element of the first optical path conversion layer is gradually larger than the light guide direction of the light from the light source as it is away from the end face of the light guide. It is inclined at an inclination angle. Thereby, the probability that the light from the light source is wavelength-converted and scattered as the distance from the end face of the light guide increases. Therefore, even if the intrinsic color light traveling in the light guide direction in the light guide decreases as it moves away from the end face of the light guide, it is emitted from the light exit surface of the light guide. The decrease in the brightness of the light is suppressed. As a result, the luminance uniformity is further increased.

  In the light source module according to an embodiment, the pattern element of the first optical path conversion layer extends in an elongated direction along a light guide direction of the light from the light source.

  In the light source module of this one embodiment, the pattern elements of the first optical path conversion layer are elongated along the light guide direction of the light from the light source, so that light passes through the first optical path conversion layer. Can be guided. Therefore, the light guide distance of the light from the light source can be made relatively long. Thereby, the uniformity of the brightness | luminance of the light radiate | emitted from the said light-projection surface of the said light guide further increases.

In the light source module of one embodiment,
A second optical path conversion layer that is provided on the one main surface of the light guide and is made of a translucent material that does not include a material that converts the wavelength of the light from the light source, and that guides the light from the light source. Prepared,
In the second optical path conversion layer, the ratio between the intensity of the intrinsic color light and the intensity of the light wavelength-converted by the first optical path conversion layer is substantially constant with respect to the light guide direction of the light from the light source. It arrange | positions so that it may become.

  In the light source module of this embodiment, the chromaticity uniformity of the light emitted from the light emitting surface is further enhanced.

  The first optical path conversion layer includes a plurality of pattern elements arranged along the one main surface, and the second optical path conversion layer is a gap between the pattern elements forming the first optical path conversion layer. It is desirable to include pattern elements provided in

  In the light source module of one embodiment, the first optical path conversion layer is made of a material that generates light of a complementary color with respect to the intrinsic color by the wavelength conversion.

  Here, “complementary color light for the unique color” refers to light of a color that becomes white when mixed with the unique color. For example, when the intrinsic color is blue, yellow (or red and green) is a complementary color.

  In the light source module of the present invention, a part of the light of the intrinsic color from the light source is wavelength-converted by the first optical path conversion layer inside the light guide to generate complementary color light for the intrinsic color. The complementary color light and the remaining part of the intrinsic color light from the light source are mixed to form white light. The white light is emitted to the outside from the other main surface (light emitting surface) opposite to the one main surface of the light guide. As a result, white light suitable for illumination and backlight can be obtained.

In the light source module of one embodiment,
The light sources are respectively provided on a pair of parallel end faces of the light guide,
The first optical path conversion layer has the pattern elements symmetrically with respect to a plane passing through the center of the pair of end faces.

  In the light source module of this one embodiment, many light sources are provided by one light guide. Therefore, high-intensity light is emitted from the light exit surface of the light guide to the outside. The process from the end face where each light source is provided until the light introduced into the light guide is emitted from the light exit face to the outside occurs symmetrically with respect to the plane passing through the center of the pair of end faces. . Accordingly, variations in chromaticity and luminance of light emitted from the light emitting surface are averaged symmetrically with respect to a plane passing through the center of the pair of end surfaces, and as a result, uniformity of chromaticity and luminance is improved.

  In one embodiment, the light guide is a rectangular plate, and the pair of end faces correspond to the long sides of the rectangle.

  In the light source module of this embodiment, the light guide distance of the light from the light source is relatively short. Therefore, the change in the probability of wavelength conversion and scattering by the first optical path conversion layer with respect to the light guide direction of the light from the light source is reduced. As a result, the chromaticity uniformity of the light emitted from the light exit surface is further increased.

  In one embodiment, the light guide is a rectangular plate, and the pair of end surfaces correspond to the short sides of the rectangle.

  In the light source module of this embodiment, the light guide distance of the light from the light source is relatively long. Therefore, the amount of light that is wavelength-converted and scattered by the first optical path conversion layer with respect to the light guide direction of the light from the light source increases as a whole. As a result, the chromaticity of the light emitted from the light emitting surface has many components of the color of the light subjected to wavelength conversion by the first optical path conversion layer. For example, if the light wavelength-converted by the first optical path conversion layer is yellow light, the chromaticity of the light emitted from the light exit surface has a large amount of yellow components. Therefore, a light source with high yellowness is obtained.

The light source module manufacturing method of the present invention is a light source module manufacturing method for producing the light source module,
Forming the pattern element of the first optical path conversion layer on the one main surface of the light guide by printing using a mask,
The light source is attached to the end face of the light guide.

  According to the light source module manufacturing method of the present invention, even if the light guide has a large area, the light source module can be manufactured easily and inexpensively in a short time.

In another aspect, the light source module of the present invention includes:
A light guide that transmits light;
A light source that is optically connected to at least one of the end faces of the light guide and emits light of a specific color toward the inside of the light guide;
A first optical path conversion layer provided on one main surface perpendicular to the end face of the light guide and including a material for wavelength-converting the light from the light source;
A second optical path conversion layer that is provided on the one main surface of the light guide and is made of a translucent material that does not include a material that converts the wavelength of the light from the light source, and that guides the light from the light source. Prepared,
The second optical path conversion layer has a ratio of the intensity of the intrinsic color light traveling inside the light guide and the intensity of the light wavelength-converted by the first optical path conversion layer to the light from the light source. It arrange | positions so that it may become substantially constant regarding a light guide direction, It is characterized by the above-mentioned.

  In the light source module of the present invention, a part of the light of the intrinsic color from the light source introduced into the light guide is incident on the first optical path conversion layer, and the wavelength is converted by the first optical path conversion layer. Scattered. Then, the wavelength-converted light and the remaining part of the intrinsic color light from the light source are mixed inside the light guide. The mixed light is emitted to the outside from the other main surface (light emitting surface) opposite to the one main surface of the light guide. Also, thanks to the second optical path conversion layer, the ratio between the intensity of the intrinsic color light traveling inside the light guide and the intensity of the light wavelength-converted in the first optical path conversion layer is from the light source. The light guiding direction is substantially constant. Therefore, the chromaticity uniformity of the light emitted from the light emitting surface is increased regardless of the position in the light guide.

  Moreover, in this invention, the light radiate | emitted from the light source (for example, LED) advances by totally reflecting within a light guide. Since the light guide is a light guide member that transmits light, the member itself absorbs little light, and since the light is guided by totally reflecting the inside, there is almost no loss of light amount due to reflection. Therefore, the ratio of light that can be used in the light source module out of the light emitted from the light source is high, and a light source module with high light use efficiency can be manufactured.

In another aspect, the method for producing a light source module of the present invention is a method for producing a light source module for producing the light source module,
The pattern element of the first optical path conversion layer is formed by printing using a mask, and the pattern element included in the second optical path conversion layer is formed by printing using a mask,
The light source is attached to the end face of the light guide.

  According to the light source module manufacturing method of the present invention, even if the light guide has a large area, the light source module can be manufactured easily and inexpensively in a short time.

  In the light source module of one embodiment, a diffusing member that diffuses light emitted from the other main surface to the outside is disposed opposite to the other main surface opposite to the one main surface of the light guide. It is characterized by.

  In the light source module according to this embodiment, light emitted to the outside from the other main surface (light emission surface) of the light guide is diffused by the diffusion member. Accordingly, the uniformity of chromaticity and luminance of light emitted to the outside is further increased.

  In the light source module of one embodiment, a reflecting member is disposed so as to face the one main surface of the light guide and to reflect light to be emitted from the one main surface to the outside toward the light guide. It is characterized by being.

  In the light source module according to this embodiment, light that is about to be emitted from the one main surface of the light guide to the outside is reflected to the light guide by the reflection member. As a result, the reflected light is emitted from the other main surface (light emitting surface) to the outside through the light guide. Therefore, the brightness of the light emitted to the outside increases.

  An electronic apparatus according to the present invention is an electronic apparatus including the light source module.

  In the electronic device of the present invention, since the light source module is thin, a thin electronic device such as a thin lighting device or a liquid crystal display device can be configured. Since the chromaticity and luminance uniformity of the light emitted from the light source module is high, a high-performance electronic device can be configured. In addition, the member cost can be reduced, and the electronic device can be configured at low cost.

  Thus, according to the present invention, it is possible to provide a light source module that is thin and has uniform luminance and chromaticity.

It is a figure which shows the place which looked at the light source module of one Embodiment of this invention from upper direction. It is a figure which shows the planar layout of the light source module of FIG. It is a figure which shows the planar layout of the light source module of a comparative example. It is a figure which shows the measurement result of the chromaticity of the light source module of FIG. 3A. It is a figure which shows the measurement result of the brightness | luminance of the light source module of FIG. 3A. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure which shows the measurement result of the chromaticity of the light source module of FIG. 4A. It is a figure which shows the measurement result of the brightness | luminance of the light source module of FIG. 4A. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure which shows the measurement result of the chromaticity of the light source module of FIG. 10A. It is a figure which shows the measurement result of the brightness | luminance of the light source module of FIG. 10A. It is a figure which shows the structural example formed by providing the 2nd optical path change layer along with the strip | belt-shaped pattern element of the 1st optical path change layer in FIG. 10A. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure which shows the plane layout of the light source module of one Embodiment of this invention. It is a figure explaining the method of producing the light source module shown in FIG. 1 and FIG. It is a figure which shows the place which looked at the light source module of one Embodiment from diagonally. FIG. 16 is a diagram showing an example in which a plurality of light source modules in FIG. 15 are arranged in a direction perpendicular to the longitudinal direction of the light guide. It is a figure which shows the example of a structure different from FIG. 11 in which the 2nd optical path change layer is provided along with the strip | belt-shaped pattern element of the 1st optical path change layer in FIG. 10A. It is a figure which shows the place which looked at the light source module of one Embodiment of this invention from diagonally. It is a figure which shows the measurement result of the chromaticity of the light source module of FIG. 18 compared with the measurement result when a 2nd optical path change layer is abbreviate | omitted.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
2 shows a planar layout of the light source module 60 of one embodiment, and FIG. 1 shows the light source module 60 viewed from above in FIG. 2 (in other words, FIG. 2 shows the light source module 60 in FIG. In FIG. 5).

  As can be clearly understood from FIG. 2, the light source module 60 includes a light guide plate 2 as a light guide made of a rectangular plate material, and a plurality of (three in this example) attached to the end surface 2 e of the light guide plate 2. The light source 1 which consists of blue LED1a, and the 1st optical path conversion layer 30 provided in one main surface 2b perpendicular | vertical to the end surface 2e of the light-guide plate 2 are provided.

  The light source 1 only needs to emit light of a specific color, that is, light indicating a specific hue other than white. In this example, as described above, it is assumed that the light source 1 is composed of a plurality of blue LEDs 1a that emit blue light as an intrinsic color. Each blue LED 1a is configured by accommodating a blue LED chip (not shown) in a package having a size substantially equal to the size of the chip. The package contains no phosphor material. Thereby, the problems i) to vi) related to the white LED light source described above can be solved.

  The plurality of blue LEDs 1a are arranged at an equal pitch along the longitudinal direction of the end surface 2e (the Y direction in FIG. 2). Each blue LED 1a is optically connected to the end surface 2e of the light guide plate 2, and emits blue light toward the inside of the light guide plate 2 in a direction (X direction in FIG. 2) perpendicular to the end surface 2e. Therefore, the light guide direction (meaning the main traveling direction) of the light from the blue LED 1a, excluding scattered light and the like inside the light guide plate 2, is the X direction.

  The material of the light guide plate 2 is not particularly limited as long as it is a material that transmits light emitted from the light source 1. In this example, the light guide plate 2 is made of acrylic, but other examples include polycarbonate, polyolefin, silicon, and epoxy resins. Further, glass may be used.

  The first optical path conversion layer 30 is composed of a phosphor as a wavelength conversion substance that converts the wavelength of light from the light source 1 and a resin that holds the phosphor. In this example, the first optical path conversion layer 30 is configured by dispersing, in an acrylic UV (ultraviolet) curable resin, a phosphor that generates a complementary color to blue light emitted from the blue LED 1a, that is, yellow light. The first optical path conversion layer 30 is composed of a plurality of pattern elements 3a arranged in a matrix along the X direction (direction perpendicular to the end face 2e) and the Y direction on the main surface 2b. In this example, the shape of each pattern element 3a is a rectangular shape whose dimension in the Y direction is shorter than that in the X direction.

  When the first optical path conversion layer 30 is formed by printing, a mixed resin (usually called resin ink, printing ink, or ink) in which a phosphor is dispersed in a resin is prepared, and the mixed resin is used. By applying it in various shapes, a phosphor pattern can be produced. As will be described in detail later, when the first optical path conversion layer 30 is formed by printing, a resin is spread on the mask from which the pattern is cut out, and the mixed resin is transferred from the mask to the light guide plate 2 according to the shape of the pattern. .

  As said resin, transparent resin which does not absorb the light from a light source as much as possible is preferable. Further, a curable resin or a resin in which a resin is dissolved in a solvent is preferable so that an arbitrary shape can be applied on the light guide plate 2. For example, in addition to the above-described acrylic UV curable resin, epoxy-based, silicon-based UV curable resin, thermosetting resin, and the like can be given. Alternatively, a resin in a state where an acrylic resin, an epoxy resin, or a silicon resin is dissolved in an organic solvent such as an aromatic resin or a ketone resin can be given.

Furthermore, fine particles such as SiO ₂ and TiO ₂ or polymer fine particles having various particle diameters from several nanometers to several tens of micrometers may be added to these resins. For example, examples of such fine particles include Aerosil (manufactured by EVONIK) and FUN-COAT (manufactured by Jujo Chemical Co., Ltd.). By adding these fine particles, the following effects can be obtained.

  First, by adding fine particles to the resin, the thixotropy of the resin can be improved. The improvement in thixotropy has the effect of reducing the fluidity of the stationary state when the resin is applied on the substrate, and in the case of patterning, it has the effect of improving the aspect ratio of the pattern. Further, the improvement in thixotropy has the effect of improving the resin detachability and separation from the printing mask when the first optical path conversion layer 30 is pattern-transferred using a mask. In order to increase the transfer accuracy and transfer speed, the resin needs to be separated from the mask efficiently. By increasing the thixotropy of the resin by adding fine particles, the transfer accuracy and the printing speed can be improved.

  Moreover, the light diffusibility of resin can be raised by adding microparticles | fine-particles to resin. The improvement of the light diffusibility of the resin is such that when the first optical path conversion layer 30 (and the second optical path conversion layer described later) is formed on the light guide plate 2 by the resin, the light incident on the first optical path conversion layer 30 is more diffused. It has the effect of scattering. The fact that the light emitted from the first optical path conversion layer and the second optical path conversion layer is more diffusive, as a result, helps the effect described later, which improves the uniformity of the luminance and chromaticity of the light emitted from the light guide plate 2. .

  In this light source module 60, part of the blue light from each blue LED 1 a introduced into the light guide plate 2 enters the first optical path conversion layer 30, and wavelength conversion is performed by the phosphor of the first optical path conversion layer 30. And scattered as yellow light. And in the inside of the light-guide plate 2, the said yellow light and the remaining one part of blue light from each blue LED1a are mixed, and it becomes white light. This white light is emitted to the outside from the other main surface (light emitting surface) 2a (see FIG. 1) opposite to the one main surface 2b of the light guide plate 2.

  In this way, the first optical path conversion layer 30 converts a part of the light emitted from the light source 1 into a different wavelength, and mixes it with the light emitted from the light source 1 to obtain light of a desired color (white in the above example). Work to get. The first optical path conversion layer 30 also functions to scatter incident light from the light source 1 incident on the light guide plate 2 and output it from the light exit surface 2 a of the light guide plate 2. If the first light path conversion layer 30 is not provided on the light guide plate 2, incident light from the light source 1 only repeats total reflection between the main surfaces 2 a and 2 b of the light guide plate 2, and the light exit surface. It is hardly emitted from 2a. However, when the first optical path conversion layer 30 exists, a part of the incident light from the light source 1 is converted into light of a different wavelength by the phosphor of the first optical path conversion layer 30 and scattered. As a result, the condition is not met from the total reflection condition, and the light is emitted from the light exit surface 2 a of the light guide plate 2. The first optical path conversion layer 30 having such an effect has a convex shape from the light guide plate 2, and its height is preferably in the range of several micrometers to several tens of micrometers. Thus, if the first optical path conversion layer 30 is thinly formed to a uniform thickness, the amount of phosphor used can be reduced, and the cost can be reduced.

  In the example of FIG. 2, the shape of each pattern element 3 a of the first optical path conversion layer 30 is a rectangular shape whose dimension in the Y direction is shorter than that in the X direction. Therefore, in the light source module 60, the light from each blue LED 1a is not scattered in the light guide direction X through the gap between the pattern elements 3a arranged in the Y direction perpendicular to the light guide direction X inside the light guide plate 2. proceed. Therefore, the light guide distance of each blue LED 1a can be made relatively long, and the wavelength conversion efficiency by the first optical path conversion layer 30 is increased. Thereby, the uniformity of chromaticity and luminance of light emitted from the light emitting surface 2a of the light guide plate 2 is increased.

  In addition to the plurality of pattern elements 3a, the first optical path conversion layer may include pattern elements whose vertical and horizontal dimensions are not limited.

  The first optical path conversion layer may be provided separately for a plurality of pattern elements including phosphors of different types, for example, a pattern element that generates red light and a pattern element that generates green light.

(Second Embodiment)
FIG. 3A shows a light source module 901 as a comparative example, and FIG. 4A shows a light source module 31 of one embodiment. In these drawings, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof will be omitted (the same applies to the drawings described later).

  In the light source module 901 of FIG. 3A, the pattern of the first optical path conversion layer 90 is configured by arranging a plurality of strip-like pattern elements 90 </ b> S elongated in the substantially Y direction at equal pitches in the X direction. Each strip-shaped pattern element 90S is formed by connecting a plurality of rectangular pattern elements 90b that are short in the X direction and long in the Y direction, with a slight shift in the X direction (1/2 of the dimension in the X direction). On the other hand, in the light source module 31 of FIG. 4A, the pattern of the first optical path conversion layer 31 is configured by arranging a plurality of strip-like pattern elements 3S elongated in the substantially X direction at an equal pitch in the Y direction. Each strip-shaped pattern element 3S is formed by connecting a plurality of rectangular pattern elements 3b that are short in the Y direction and long in the X direction in the X direction while being slightly shifted in the Y direction (1/2 of the dimension in the Y direction). As a result, each strip-shaped pattern element 3 </ b> S is elongated along the substantially X direction over substantially the entire region from the side close to the end surface 2 e of the light guide plate 2 to the side far from the end surface 2 e.

  3B and 3C show the measurement results of chromaticity (x, y) and luminance (Lv) of the light source module 901 actually produced. 4B and 4C show measurement results of chromaticity (x, y) and luminance (Lv) of the light source module 31 actually produced. The horizontal axis in these FIG. 3B, FIG. 3C, FIG. 4B, and FIG. 4C represents the position of the light guide plate 2 in the X direction. Comparing the chromaticity (x, y) in FIG. 3B and the chromaticity (x, y) in FIG. 4B, FIG. 4B has higher x and y values, and the emitted light is closer to white. I understand. Further, when the luminance (Lv) in FIG. 3C is compared with the luminance (Lv) in FIG. 4C, it can be seen that the change in luminance (Lv) is smaller in FIG. 4C.

  From these results, the pattern dimension in the Y direction (direction perpendicular to the light guide direction) as compared with the pattern dimension in the X direction (light guide direction) of the first optical path conversion layer 31 as in the light source module 31 of FIG. 4A. Is short, the light guide distance of each blue LED 1a can be made relatively long, and it was confirmed that the wavelength conversion efficiency by the first optical path conversion layer is increased. As a result, it was confirmed that the uniformity of the chromaticity (white in this example) of the light emitted from the light emitting surface 2a of the light guide plate 2 was increased.

  The reason why the light emission state changes depending on whether the pattern of the first optical path conversion layer is elongated in the Y direction or elongated in the X direction is described as follows. For example, comparing the luminance distribution results of FIG. 3C and FIG. 4C, it can be seen that the luminance in the vicinity of the end surface 2e of the light guide plate 2 (the position of x = 100) is higher in FIG. 3C. The reason for this is that when the strip-shaped pattern element 90S is elongated in the Y direction as in the first optical path conversion layer 90 in FIG. 3A, the blue light immediately after the blue light from each blue LED 1a enters the light guide plate 2 This is because most of the light enters the band-shaped pattern element 90S disposed at a position close to the end face 2e, and is emitted from the light emitting surface 2a in the vicinity of the band-shaped pattern element 90S. That is, once light is incident on the band-shaped pattern element 90S disposed at a position close to the end face 2e and once scattered, the total reflection condition is broken and the light is emitted from the light exit surface 2a. Therefore, after that, the inside of the light guide plate 2 is guided to be incident on the strip-shaped pattern element 90S disposed at a position far from the end face 2e. On the other hand, when it has the strip-shaped pattern element 3S elongated in the X direction like the first optical path conversion layer 31 in FIG. 4A, immediately after the blue light from each blue LED 1a is incident on the inside of the light guide plate 2, There are few components that are incident upon the band-shaped pattern element 3S and are scattered, and it is considered that most of the incident light continues to travel inside the light guide plate 2 while maintaining the total reflection condition. From this, when it is desired to increase the amount of emitted light at a specific position in the light emitting surface 2a, it can be said that an elongated pattern element may be disposed at that position in a direction perpendicular to the light guide direction X.

  In the above example, the light source 1 is composed of the blue LED 1a that emits blue light as a unique color. However, an LED that emits light of another unique color may be used. In this case, the first optical path conversion layer may be a layer that converts the wavelength of the other specific color light and generates a complementary color light with respect to the other specific color light. Thereby, the light source module which radiate | emits the light of various colors from the light-projection surface of a light-guide plate can be comprised.

(Third embodiment)
5 and 6 show the planar layouts of the light source modules 62 and 63 of the embodiment, respectively. These light source modules 62 and 63 differ from the light source module 30 only in the pattern of the first optical path conversion layer.

  In the light source module 62 of FIG. 5, the first optical path conversion layer 32 has three patterns provided in order from the side close to the end surface 2 e to which each blue LED 1 a is attached in the X direction in the main surface 2 b of the light guide plate 2. Groups 3A, 3B, 3C are included. In the first pattern group 3A, five pattern elements 3u are arranged at an equal pitch along the Y direction on the side close to the end surface 2e to which each blue LED 1a is attached in the X direction within the main surface 2b of the light guide plate 2. It is arranged. Each pattern element 3u is formed in a rectangular shape whose dimension in the Y direction is shorter than the dimension in the X direction, like the pattern element 3a in FIG. In the second pattern group 3B, eight pattern elements 3u are arranged at an equal pitch along the Y direction in the main surface 2b of the light guide plate 2 substantially at the center in the X direction. Further, in the third pattern group 3C, 14 pattern elements 3u are arranged at an equal pitch along the Y direction on the main surface 2b of the light guide plate 2 on the side far from the end surface 2e to which each blue LED 1a is attached. It has been done. As described above, the number of pattern elements 3u increases as the distance from the end surface 2e of the light guide plate 2 increases, so that the distribution density of the first optical path conversion layer 32 increases as the distance from the end surface 2e of the light guide plate 2 increases.

  In the light source module 63 of FIG. 6, the first optical path conversion layer 33 has three patterns provided in order from the side close to the end surface 2 e to which each blue LED 1 a is attached in the X direction in the main surface 2 b of the light guide plate 2. It includes groups 3A ', 3B', 3C '. It consists of a plurality of rectangular pattern elements 3u whose dimensions in the Y direction are shorter than those in the X direction. In the first pattern group 3A ′, five pattern elements 3u are arranged at equal pitches along the Y direction on the side close to the end surface 2e to which each blue LED 1a is attached in the X direction within the main surface 2b of the light guide plate 2. It is arranged with. Each pattern element 3u is formed in a rectangular shape whose dimension in the Y direction is shorter than the dimension in the X direction, like the pattern element 3a in FIG. In the main pattern 2b of the light guide plate 2, the second pattern group 3B ′ has five pattern elements 3v arranged at an equal pitch along the Y direction substantially at the center in the X direction. Each pattern element 3v is formed in a rectangular shape whose dimension in the Y direction is shorter than the dimension in the X direction, but the dimension in the Y direction is set to about twice that of the pattern element 3u. In the third pattern group 3C ′, four pattern elements 3w are arranged at an equal pitch along the Y direction on the side far from the end face 2e to which each blue LED 1a is attached in the main surface 2b of the light guide plate 2. It is a thing. Each pattern element 3w is formed in a rectangular shape whose dimension in the Y direction is shorter than the dimension in the X direction, but the dimension in the Y direction is set to about four times that of the pattern element 3u. As described above, the dimension of the pattern element in the Y direction increases as the distance from the end surface 2e of the light guide plate 2 increases, so that the distribution density of the first optical path conversion layer 32 increases as the distance from the end surface 2e of the light guide plate 2 increases.

  As described above, the distribution density of the first optical path conversion layers 32 and 33 shown in FIGS. 5 and 6 increases as the distance from the end surface 2 e of the light guide plate 2 increases, that is, as the distance from the light source 1 increases. Thereby, the probability that the blue light from each blue LED 1a is wavelength-converted and scattered as the distance from the end surface 2e of the light guide plate 2 increases. Therefore, even if the blue light traveling in the light guide direction X in the light guide plate 2 decreases as it moves away from the end surface 2e of the light guide plate 2, it is emitted from the light exit surface 2a (see FIG. 1) of the light guide plate 2. A decrease in light brightness is suppressed. As a result, the luminance uniformity is further increased.

  In this way, by changing the distribution density of the first optical path conversion layer with respect to the light guide direction X, the amount of emitted light can be controlled according to the position in the light emitting surface 2a.

(Fourth embodiment)
7 and 8 show the planar layouts of the light source modules 64 and 65 of the embodiment, respectively. These light source modules 64 and 65 differ from the light source module 30 only in the pattern of the first optical path conversion layer.

  In the light source module 64 of FIG. 7, the first optical path conversion layer 34 includes five pattern elements 3 </ b> D extending in the Y direction that extend from the side close to the end surface 2 e to which each blue LED 1 a is attached to the side far from the X direction. They are arranged in pieces. Each pattern element 3D has a shape in which the dimension in the Y direction is shorter than the dimension in the X direction. More specifically, each pattern element 3D has an acute isosceles triangle shape in which the dimension in the Y direction increases as the distance from the end surface 2e of the light guide plate 2 increases. ing. As described above, the dimension in the Y direction of the pattern element 3D increases as the distance from the end surface 2e of the light guide plate 2 increases, so that the distribution density of the first optical path conversion layer 34 increases as the distance from the end surface 2e of the light guide plate 2 increases. .

  In the light source module 64 of FIG. 8, the first optical path conversion layer 35 includes a pattern element 3 </ b> E that extends from the side near the end face 2 e to which each blue LED 1 a is attached in the X direction to a substantially central portion along the Y direction. Seven pattern elements 3F are arranged on the side far from the end face 2e, and pattern elements 3F that integrally connect these pattern elements 3E are arranged. Each pattern element 3E is substantially shaped like a sharp isosceles triangle whose dimension in the Y direction is shorter than the dimension in the X direction, more specifically, the dimension in the Y direction increases as the distance from the end face 2e of the light guide plate 2 increases. It has become. The pattern element 3F has a trapezoidal shape obtained by extending each pattern element 3E to the side far from the end face 2e and overlapping it. In this way, the dimension in the Y direction of the pattern element 3E increases as the distance from the end surface 2e of the light guide plate 2 increases. By overlapping, the distribution density of the first optical path conversion layer 35 increases as the distance from the end surface 2e of the light guide plate 2 increases. ing.

  As described above, the distribution density of the first optical path conversion layers 34 and 35 shown in FIGS. 7 and 8 is the same as that of the first optical path conversion layers 32 and 33 shown in FIGS. 5 and 6. The distance increases as the distance from the end face 2e increases, that is, as the distance from the light source 1 increases. Moreover, the pattern element 3 </ b> D of the first optical path conversion layer 34 and the pattern element 3 </ b> E of the first optical path conversion layer 35 are elongated along the light guide direction X. Thereby, the probability that the blue light from each blue LED 1a is wavelength-converted and scattered is increased as the distance from the end surface 2e of the light guide plate 2 is increased over substantially the entire area of the light guide plate 2 in the X direction. Therefore, even if the blue light traveling in the light guide direction X in the light guide plate 2 decreases as it moves away from the end surface 2e of the light guide plate 2, it is emitted from the light exit surface 2a (see FIG. 1) of the light guide plate 2. A decrease in light brightness is suppressed. As a result, the luminance uniformity is further increased.

  Note that the shapes of the pattern element 3D of the first optical path conversion layer 34 and the pattern element 3E of the first optical path conversion layer 35 are not limited to acute isosceles triangles, and spread in a curved manner as the distance from the end face 2e of the light guide plate 2 increases. The shape may change.

  Further, the entire first optical path conversion layer 35 in FIG. 8 can be grasped as one pattern element.

(Fifth embodiment)
FIG. 9 shows a planar layout of the light source module 66 of the embodiment.

  In the light source module 66, the first optical path conversion layer 36 includes a plurality of pattern elements arranged in a matrix along the X direction and the Y direction. Pattern elements 3c-1, 3c-2, 3c-3,..., 3c-m arranged along the X direction form one row. Such rows are arranged in six rows at equal pitches along the Y direction. In each row, the shape of the pattern element 3c-1 disposed on the side close to the end face 2e of the light guide plate 2 is a rectangular shape whose dimension in the Y direction is shorter than that in the X direction. As the distance from the end surface 2e of the light guide plate 2 increases, the pattern elements 3c-2, 3c-3,..., 3c-m are inclined with a gradually increasing inclination angle with respect to the X direction. In other words, as the distance from the end surface 2e of the light guide plate 2 increases, the rotation angle around the center of each of the pattern elements 3c-2, 3c-3, ..., 3c-m gradually increases. Note that the amount of change in the rotation angle for each pattern element can be set arbitrarily, and the rotation direction may be reversed.

  In general, the luminance of the light emitted from the light emitting surface 2a tends to gradually decrease as the distance from the end surface 2e of the light guide plate 2 increases. Here, the strip-shaped pattern element 90S elongated in the Y direction of the first optical path conversion layer 90 in FIG. 3A is compared with the strip-shaped pattern element 3S elongated in the X direction of the first optical path conversion layer 31 in FIG. 4A. As described above, when it is desired to increase the amount of emitted light at a specific position in the light emitting surface 2a, it can be said that an elongated pattern element may be disposed at that position in a direction perpendicular to the light guide direction X. 9, the pattern elements 3c-2, 3c-3,..., 3c-m are inclined at a gradually increasing inclination angle with respect to the X direction as the distance from the end surface 2e of the light guide plate 2 increases. Thereby, the probability that the blue light from each blue LED 1a is wavelength-converted and scattered as the distance from the end surface 2e of the light guide plate 2 increases. Therefore, even if the blue light traveling in the light guide direction X in the light guide plate 2 decreases as it moves away from the end surface 2e of the light guide plate 2, it is emitted from the light exit surface 2a (see FIG. 1) of the light guide plate 2. A decrease in light brightness is suppressed. As a result, the luminance uniformity is further increased.

  Note that the same effect can be obtained for the second optical path conversion layer described later if long and narrow pattern elements are provided in a direction perpendicular to the light guide direction X.

(Sixth embodiment)
FIG. 10A shows a light source module 67 according to an embodiment.

  In the light source module 67, the pattern of the first optical path conversion layer 37 is configured by arranging a plurality of strip-like pattern elements 3G elongated in the X direction at equal pitches in the Y direction. As shown in the lower part of FIG. 10A, each band-like pattern element 3G includes a plurality of pattern elements 3x-1, 3x-2, 3x-3,..., 3x-i,. It is configured in series. More specifically, in each band-shaped pattern element 3G, the shape of the pattern element 3x-1 disposed on the side close to the end face 2e of the light guide plate 2 is a rectangular shape whose dimension in the Y direction is shorter than that in the X direction. It has become. As the distance from the end surface 2e of the light guide plate 2 increases, the pattern elements 3x-2, 3x-3,..., 3x-i,. Dimensions are getting shorter.

  As a result, the distribution density of the first optical path conversion layer 37 increases as the distance from the end surface 2 e of the light guide plate 2 increases, that is, as the distance from the light source 1 increases. Moreover, the strip-shaped pattern element 3G of the first optical path conversion layer 37 extends elongated along the X direction over substantially the entire region from the side close to the end surface 2e of the light guide plate 2 to the side far from it.

  Thereby, the probability that the blue light from each blue LED 1a is wavelength-converted and scattered as the distance from the end surface 2e of the light guide plate 2 increases. Therefore, even if the blue light traveling in the light guide direction X in the light guide plate 2 decreases as it moves away from the end surface 2e of the light guide plate 2, it is emitted from the light exit surface 2a (see FIG. 1) of the light guide plate 2. A decrease in light brightness is suppressed. As a result, the luminance uniformity is further increased. In addition, white light with an increased yellow component can be emitted.

  10B and 10C show measurement results of chromaticity (x, y) and luminance (Lv) of the light source module 67 actually produced. The horizontal axis in these FIG. 10B and FIG. 10C represents the position of the light guide plate 2 in the X direction. As can be seen from FIG. 10B, the chromaticity (x, y) is a maximum value (0.35, 0.4). Compared to the chromaticity (x, y) of FIG. 4B, in FIG. 10B, white light with further increased chromaticity and increased yellow component is obtained. Further, as can be seen from FIG. 10C, the uniformity of the luminance of the light emitted from the light emitting surface 2a is 90%. Compared to the luminance of FIG. 4C, the uniformity of luminance is higher in FIG. 10C.

  As described above, in the light source module 67 of FIG. 10A, the uniformity of the brightness can be particularly improved as compared with the light source module 31 of FIG. 4A.

(Seventh embodiment)
FIG. 11 shows a configuration example in which the second optical path conversion layer 5 is provided side by side with the band-shaped pattern element 3G of the first optical path conversion layer 37 in FIG. 10A. Specifically, as shown in an enlarged view in the lower part of FIG. 11, the second optical path conversion layer 5 is similar to the pattern elements 3x-i (i = 1, 2,..., M) of the first optical path conversion layer 37. It consists of a plurality of inclined rectangular pattern elements 5a.

Each pattern element 5a forming the second optical path conversion layer 5 is made of a light-transmitting resin that does not contain a wavelength conversion substance. The resin material is preferably a transparent material that absorbs as little light as possible from the light source 1. Further, a curable resin or a resin in which a resin is dissolved in a solvent is preferable so that an arbitrary shape can be formed on the light guide plate 2 by application. Examples include acrylic, epoxy, and silicon UV curable resins, thermosetting resins, and the like. Alternatively, a resin in a state where an acrylic resin, an epoxy resin, or a silicon resin is dissolved in an organic solvent such as an aromatic resin or a ketone resin can be given. Further, SiO ₂ , TiO ₂ fine particles or polymer-based fine particles having various particle diameters from several nanometers to several tens of micrometers may be added to these resins. For example, Aerosil (manufactured by EVONIK), FUN-COAT (manufactured by Jujo Chemical Co., Ltd.) and the like can be mentioned.

  Each pattern element 5a forming the second optical path conversion layer 5 does not include a wavelength conversion substance and thus does not have a wavelength conversion function, and guides incident light from the light source 1 incident on the light guide plate 2 (refraction, reflection, scattering, or the like). The same applies to the following). That is, when light having a certain wavelength enters each pattern element 5a forming the second optical path conversion layer 5, light having the same wavelength as the incident light is emitted from the pattern element 5a. When blue light is incident on each pattern element 5 a forming the second optical path conversion layer 5, blue light is emitted from the pattern element 5 a and guided to the light emitting surface 2 a of the light guide plate 2. Thereby, the intensity | strength of the blue light radiate | emitted from the light-projection surface 2a of the light-guide plate 2 increases in the position where the pattern element 5a is arrange | positioned.

  Generally speaking, in the configuration in which only the first optical path conversion layer is provided on the light guide plate 2, it is difficult to simultaneously improve both the luminance and chromaticity uniformity. The reason for this is that in the configuration in which only the first optical path conversion layer is provided on the light guide plate 2, two change amounts of the change in luminance and the change in chromaticity in the light exit surface 2 a of the light guide plate 2 are represented by the first optical path. This is because the adjustment is made only by the conversion layer (distribution density and angle). For example, as shown in FIG. 10C, high uniformity is realized for the luminance distribution. On the other hand, as shown in FIG. 10B, the chromaticity (x, y) has been improved, but gradually changed (increased) as the distance from the end surface 2e of the light guide plate 2 increases. For this reason, there is still room for improvement in chromaticity (x, y).

  On the other hand, if the second optical path conversion layer 5 is provided on the light guide plate 2 together with the first optical path conversion layer 37 as in this embodiment, two types of change in luminance and chromaticity can be obtained using two types of layers. Since it can be adjusted by arrangement, it is easy to achieve uniform luminance and chromaticity at the same time. In the above-described example, the chromaticity (x, y) is increased at the end of the light guide plate 2 far from the end surface 2e of the light guide plate 2 within the light exit surface 2a. Accordingly, as shown in FIG. 11, each pattern element 5 a forming the second optical path conversion layer 5 is arranged at the end portion 38 far from the end surface 2 e of the light guide plate 2. More specifically, the respective pattern elements 5a are arranged in the gaps between the pattern elements 3x-i forming the strip-shaped pattern elements 3G of the first optical path conversion layer 37 at the end portion 38 on the side far from the end face 2e of the light guide plate 2. . Thereby, the ratio between the intensity of the blue light from the light source 1 and the intensity of the yellow light wavelength-converted by the first optical path conversion layer 37 can be made substantially constant with respect to the light guide direction X (left and right direction in FIG. 11). it can. As a result, the chromaticity uniformity of the light emitted from the light emitting surface 2a is further increased. That is, the uniformity of both the luminance and chromaticity of the white light emitted from the light emitting surface 2a can be improved.

(Eighth embodiment)
FIG. 12 shows a planar layout of the light source module 70 of one embodiment.

  In this light source module 70, light sources 1 and 1 ′ are provided on a pair of end faces 2 e and 2 f parallel to each other corresponding to the rectangular short side of the light guide plate 2. Each of the light sources 1 and 1 'includes a plurality (three in this example) of blue LEDs 1a. The first optical path conversion layer 39 has a plurality of pattern elements 3G and 3G ′ arranged along the Y direction symmetrically with respect to a plane L1 passing through the center of the pair of end faces 2e and 2f.

  Each strip-shaped pattern element 3G disposed on the side close to the end face 2e of the light guide plate 2 is configured in exactly the same manner as described with reference to FIG. Each strip pattern element 3G ′ arranged on the side close to the end face 2f of the light guide plate 2 is configured symmetrically with respect to the corresponding strip pattern element 3G and the plane L1. The mutually corresponding band-like pattern elements 3G and 3G ′ are continuous in the X direction on the plane L1.

  Although not shown in FIG. 12, in the central portion 39a in the main surface 2b of the light guide plate 2 with respect to the X direction, the band-shaped pattern element of the first optical path conversion layer 39 is the same as shown in FIG. Each pattern element 5a forming the second optical path conversion layer 5 is disposed in a gap between the pattern elements 3x-i forming 3G and 3G ′.

  In the light source module 70, as compared with the light source module 67 of FIG. Therefore, high-luminance light is emitted from the light emission surface 2a of the light guide plate 2 to the outside. The process from the end faces 2e and 2f provided with the light sources 1 and 1 'to the outside where the blue light introduced into the light guide plate 2 is emitted from the light exit surface 2a is related to the central plane L1. It happens symmetrically. Accordingly, variations in chromaticity and luminance of light emitted from the light emitting surface 2a are averaged symmetrically with respect to the central plane L1, and as a result, uniformity of chromaticity and luminance is improved.

  Further, the light guide distance of the blue light from each of the light sources 1 and 1 ′ is relatively long (compared to the light source module of FIG. 13 described later). Therefore, as a whole, the amount of light that is wavelength-converted and scattered by the first optical path conversion layer 39 with respect to the light guide direction X of the blue light from each light source 1, 1 ′ increases. As a result, the chromaticity of the light emitted from the light emitting surface 2 has a lot of yellow components. Therefore, a light source with high yellowness is obtained.

  In this embodiment, the first optical path conversion layer 37 and the second optical path conversion layer 5 shown in FIG. 11 are arranged symmetrically, but the pattern shapes of the first optical path conversion layer and the second optical path conversion layer are the same. It is not limited. Even if the first optical path conversion layers described in the above embodiments are arranged symmetrically, similarly, chromaticity and luminance variations of light emitted from the light emitting surface 2a are symmetrical with respect to the central plane L1. The effect of averaging is obtained. Further, the number of blue LEDs 1a constituting each of the light sources 1 and 1 'is not limited to three, and may be four or more, for example. Further, the second optical path conversion layer 5 may be omitted.

(Ninth embodiment)
FIG. 13 shows a planar layout of the light source module 71 of one embodiment.

  In the light source module 71, light sources 1 and 1 ′ are provided on a pair of end faces 2 c and 2 d that are parallel to each other and correspond to the long side of the light guide plate 2. Each of the light sources 1 and 1 'includes a plurality (three in this example) of blue LEDs 1a. The first optical path conversion layer 40 has a plurality of pattern elements 3H and 3H ′ arranged in the X direction symmetrically with respect to a plane L2 passing through the center of the pair of end faces 2c and 2d.

  Each band-shaped pattern element 3H arranged on the side close to the end face 2c of the light guide plate 2 is configured in such a manner that the band-shaped pattern element 3G described with reference to FIG. Further, each strip-shaped pattern element 3H ′ arranged on the side close to the end face 2d of the light guide plate 2 is configured symmetrically with respect to the corresponding strip-shaped pattern element 3H and the plane L2. The mutually corresponding strip-like pattern elements 3G and 3G ′ are continuous in the Y direction at the plane L2.

  Although not shown in FIG. 13, the elements in FIG. 11 are rotated 90 ° in the central portion 40 a with respect to the Y direction in the main surface 2 b of the light guide plate 2, and the first optical path conversion layer 40 is rotated. Each pattern element 5a forming the second optical path conversion layer 5 is disposed in a gap between the pattern elements 3x-i forming the band-shaped pattern elements 3H and 3H ′.

  In the light source module 71, as in the light source module 70 of FIG. 11, a large number of light sources 1 and 1 ′ are provided on one light guide plate 2. Therefore, high-luminance light is emitted from the light emission surface 2a of the light guide plate 2 to the outside. The process from the end faces 2c and 2d provided with the light sources 1 and 1 'to the outside where the blue light introduced into the light guide plate 2 is emitted from the light exit surface 2a is related to the central plane L2. It happens symmetrically. Therefore, variations in chromaticity and luminance of light emitted from the light emitting surface 2a are averaged symmetrically with respect to the central plane L2, and as a result, uniformity of chromaticity and luminance is improved.

  Further, in the light source module 71, the light guide distance of the blue light from the light sources 1 and 1 'is relatively short as compared with the light source module 70 of FIG. Therefore, the change in the probability that the wavelength is converted and scattered by the first optical path conversion layer 40 in the light guide direction Y of the blue light from the light sources 1 and 1 ′ is reduced. As a result, the chromaticity uniformity of the light emitted from the light emitting surface 2a is further increased.

(10th Embodiment)
With reference to FIG. 14, a method for manufacturing the light source module 60 shown in FIGS. 1 and 2 will be described as an example.

  First, the first optical path conversion layer 30 is formed on the light guide plate 2 by printing, in this example, by a screen printing method. At this time, the printing mask 6, the printing ink 7, and the squeegee 8 for spreading the printing ink 7 over the entire mask are prepared in advance. The printing mask 6 has a plurality of holes 6 a having shapes corresponding to the pattern elements 3 a of the first optical path conversion layer 30. Then, a mixed resin 7 for forming the first optical path conversion layer 30 is applied on the mask 6, and the mixed resin 7 is spread over the entire surface of the light guide plate 2 using the squeegee 8. Thereby, the 1st optical path changing layer 30 which consists of a plurality of pattern elements 3a is formed. In this case, the first optical path conversion layer 30 can be formed easily and inexpensively in a short time.

  Thereafter, a plurality of blue LEDs 1a as the light source 1 are optically connected to the end surface 2e of the light guide plate 2 (see FIG. 2).

  In this case, even if the light guide plate 2 has a large area, the light source module 60 (and the other light source modules described above) can be manufactured easily and inexpensively in a short time.

  In addition, when providing the 2nd optical path conversion layer 5 shown in FIG. 11, after attaching the several blue LED 1a as the light source 1 after forming the 1st optical path conversion layer 30 in the light-guide plate 2, printing, for example, The second optical path conversion layer 5 may be formed by a screen printing method.

  The light source module described above is suitably used for various electronic devices. That is, since the above-described light source module is thin, for example, a thin lighting device or a liquid crystal display device can be configured. In addition, since the chromaticity and luminance uniformity of the light emitted from the light source module is high, a high-performance electronic device can be configured. In addition, the member cost can be reduced, and the electronic device can be configured at low cost.

(Eleventh embodiment)
FIG. 15 shows a light source module 80 according to an embodiment as viewed from an oblique direction.

  The light source module 80 includes a rectangular bar-shaped light guide 20 that is rectangular in cross section and extends in one direction (X direction). One blue LED 1a as a light source is provided on each of a pair of end faces 20e and 20f parallel to each other of the light guide 20. The reason why the blue LEDs 1a are used one by one is that they correspond to the sizes of the light guides 20e and 20f.

  A pattern element (not shown) that forms a first optical path conversion layer symmetrically with respect to a plane L3 passing through the center of the pair of end surfaces 20e, 20f on one main surface 20b perpendicular to the end surfaces 20e, 20f of the light guide 20. (In this example, the same pattern elements 3G and 3G 'as shown in FIG. 12) are provided. If the dimension of the main surface 20b in the Y direction permits, a plurality of pattern elements 3G and 3G ′ may be arranged along the Y direction.

  The materials of the light guide 20 and the first optical path conversion layer are the same as those described in the first embodiment.

  In this light source module 80, the blue light from each blue LED 1a has a wavelength as it approaches the center from the end faces 20e, 20f of the light guide 20 due to the pattern elements (3G, 3G ′) forming the first optical path conversion layer. The probability of being transformed and scattered is increasing. Therefore, even if the blue light traveling in the light guide direction in the light guide 20 decreases as it approaches the center of the light guide 20, the brightness of the light emitted from the light exit surface 20a of the light guide 20 is reduced. Is suppressed. The process from the end faces 20e, 20f provided with the LEDs 1a, 1a to the blue light introduced into the light guide 20 to the outside from the light emitting face 20a is symmetric with respect to the central plane L3. To happen. Accordingly, the chromaticity and luminance variations of the light emitted from the light emitting surface 20a are averaged symmetrically with respect to the central plane L3, and as a result, the uniformity of chromaticity and luminance is improved.

  In addition, since the light source module 80 includes the rectangular bar-shaped light guide 20, the volume of the light guide 20 is smaller than that of the light guide plate 2 in each of the above-described embodiments. Therefore, the material cost of the light guide 20 is relatively low, and the cost can be reduced. Furthermore, the weight of other optical members (not shown) can be reduced. Therefore, it is possible to reduce the weight of the light source module 80 and electronic devices such as a backlight and a lighting fixture.

  As shown in FIG. 16, a large area light source module 81 is arranged by arranging a plurality of light source modules 80 in a direction (Y direction) perpendicular to the longitudinal direction of the light guide 20 with respect to the display screen 82. May be configured. In the example of FIG. 16, four sets of light source modules 80 are arranged side by side in the Y direction (note that the LED 1a on the end face 20e side is not shown in FIG. 16). In this case, the elongated light source module 80 substantially constitutes a light source having a relatively large area. Such a light source is preferably used as a backlight for a large-area display screen 82.

(Twelfth embodiment)
FIG. 17 shows a configuration example different from FIG. 11 in which the second optical path conversion layer 5 ′ is provided side by side with the band-shaped pattern element 3 G of the first optical path conversion layer 37 in FIG. 10A. Specifically, as shown in an enlarged view in the lower part of FIG. 17, the second optical path conversion layer 5 ′ includes a plurality of circular (dot) pattern elements 5 b.

  Each pattern element 5b forming the second optical path conversion layer 5 ′ is arranged on a straight line 5c-j (j = 1, 2,..., N) extending in the Y direction. An interval between straight lines adjacent to each other in the X direction (for example, 5c-j and straight line 5c- (j + 1)), that is, a pitch in the X direction of the pattern element 5b is represented by a symbol a. The pitch in the Y direction of the pattern element 5b is represented by the symbol b.

In this example, the pitch b in the Y direction of the pattern element 5b is constant. On the other hand, the X-direction pitch a of the pattern elements 5b depends on the distance X from the end surface 2e of the light guide plate 2 (see FIG. 10A),
a = 0.0001X ² −0.0148X + 0.9382 (1)
(Unit is mm).

  When the X-direction pitch a of the pattern elements 5b is set as in Expression (1), as can be seen from the upper stage in FIG. 17, at the end portion on the side close to the end surface 2e of the light guide plate 2 (side where X is small), The density of the pattern element 5b is sparse with respect to the X direction. As the distance from the end surface 2e of the light guide plate 2 increases, the density of the pattern elements 5b becomes dense in the X direction.

  When the pattern elements 5b of the second optical path conversion layer 5 ′ are arranged in this way, the chromaticity uniformity of the light emitted from the light emitting surface 2a (see FIG. 1) is further enhanced. That is, the uniformity of both the luminance and chromaticity of the white light emitted from the light emitting surface 2a can be improved.

  The method of setting the pitch a in the X direction and the pitch b in the Y direction of the pattern element 5b is not limited to the above example, and both the luminance and chromaticity of the light emitted from the light emitting surface 2a are uniform. It is desirable that the property can be improved.

  In the above example, the pattern element 5b has a circular shape. However, the pattern element 5b may have a band shape, and the shape is not particularly limited. The region where the pattern element 5b is arranged may be applied to the entire gap between the pattern elements 3x-i forming the first optical path conversion layer 37, or may be applied partially.

(13th Embodiment)
FIG. 18 shows a light source module 83 according to an embodiment as viewed obliquely.

  In the light source module 83, light sources 1 and 1 ′ are provided on a pair of end surfaces 2 e and 2 f corresponding to the rectangular short side of the light guide plate 2, respectively. Each of the light sources 1 and 1 'includes a plurality (three in this example) of blue LEDs 1a.

  Although not shown in FIG. 18, on the main surface 2b of the light guide plate 2, the first optical path conversion layer 37 and the second optical path conversion layer 5 ′ combined as shown in FIG. In the same manner as shown in FIG. 6, the planes L1 are symmetrically provided with respect to a plane L1 passing through the center of the pair of end faces 2e and 2f.

  On the main surface 2b of the light guide plate 2, a flat plate-like reflecting member 11 is disposed in parallel to the main surface 2b. In this example, the reflecting member 11 is in contact with the main surface 2 b of the light guide plate 2. The reflecting member 11 reflects light that is about to be emitted from the main surface 2b of the light guide plate 2 to the light guide plate 2 side. As a result, the reflected light exits from the light exit surface 2a through the light guide plate 2 to the outside. Therefore, it is possible to increase the luminance of the light emitted from the light emitting surface 2a to the outside.

  On the light emitting surface 2a opposite to the main surface 2b of the light guide plate 2, a flat plate-like diffusing member 10 is disposed in parallel to the light emitting surface 2a. In this example, the diffusing member 10 is disposed at a position separated from the light emitting surface 2 a of the light guide plate 2 by a distance c. The diffusing member 10 diffuses light emitted from the light emitting surface 2a to the outside. Therefore, the uniformity of chromaticity and luminance of light emitted to the outside can be improved. Although the distance c can be set variably, in this example, the distance c is set to 25 mm.

  FIG. 19 shows the measurement result of the chromaticity y of the light source module 83 shown in FIG. 18, with the distance c between the light emitting surface 2a of the light guide plate 2 and the diffusing member 10 as a parameter, the second optical path conversion layer 5 ′. It is shown in comparison with the measurement result when is omitted. The horizontal axis in FIG. 19 represents the position of the light guide plate 2 in the X direction. The vertical axis in FIG. 19 represents chromaticity y in the XYZ color system.

  Data D0 in FIG. 19 indicates the chromaticity y when the second optical path conversion layer 5 ′ is not present (that is, only the first optical path conversion layer 37 in which the band-shaped pattern elements 3G are arranged) and the distance c = 0 mm. ing. Data D1 indicates the chromaticity y when the second optical path conversion layer 5 ′ is present and the distance c = 0 mm. Data D2 indicates the chromaticity y when the second optical path conversion layer 5 ′ is present and the distance c = 25 mm. Here, the reason why only the chromaticity y is shown is that, as can be inferred from FIG. 10B, in the light source module 83, the change in the y value is larger than the change in the x value, and the y value can be made uniform. This is because the x value can also be made uniform.

  From the comparison between the data D0 and the data D1 in FIG. 19, it can be seen that the uniformity of the chromaticity y is improved by providing the second optical path conversion layer 5 ′. Further, from the comparison between the data D1 and the data D2, the uniformity of the chromaticity y is improved by increasing the distance c between the light emitting surface 2a of the light guide plate 2 and the diffusion member 10 from 0 mm to 25 mm. I understand that.

Here, in order to evaluate quantitatively, the “uniformity of chromaticity” in the plane of white light emitted to the outside of the diffusing member 10 is defined as the following equation (2) (unit:%). ).
{(Maximum value)-(minimum value)} / (maximum value) × 100 (2)

  Then, the data D0 has “chromaticity uniformity” of 61%, and the data D1 has “chromaticity uniformity” of 59%. From this result, it is understood that the “chromaticity uniformity” is improved by 2 points by providing the second optical path conversion layer 5 ′. Further, it can be seen that the data D2 has a “chromaticity uniformity” of 8%, which is further improved. Actually, in the case of data D2, the color unevenness was improved to a level at which no color unevenness could be confirmed.

  In this way, by providing the second optical path conversion layer 5 ′ and optimizing the distance c between the light emitting surface 2 a of the light guide plate 2 and the diffusing member 10, the white light emitted from the diffusing member 10 can be reduced. The uniformity of chromaticity can be improved.

  Note that the method of quantitative evaluation of chromaticity uniformity is not limited to the definition of Expression (2), and other definitions such as dispersion with respect to an average value may be used.

  In the above example, the distance c between the light emitting surface 2a of the light guide plate 2 and the diffusing member 10 is set to 25 mm, but the present invention is not limited to this. This distance c can be variably set from 0 mm (in contact) to an arbitrary value. In order to reduce the thickness of the light source module, when the value of the distance c is set to be smaller, the pattern element 5b of the second optical path conversion layer 5 ′ is set to the central portion of the light guide plate 2, that is, X in FIG. It is desirable to arrange them at high density on the side that takes a large value. Thereby, the chromaticity can be further uniformized.

  Moreover, in the above-mentioned example, although the reflection member 11 is arrange | positioned so that the light-guide plate 2 may be contacted, it is not restricted to this. An arbitrary space may be provided between the main surface 2 b of the light guide plate 2 and the reflecting member 11.

  Further, in the light source module 83 described above, the first optical path conversion layer 37 and the second optical path conversion layer 5 ′ combined as shown in FIG. 17 are formed on the main surface 2b of the light guide plate 2 as shown in FIG. In the same manner as described above, it is assumed that they are provided symmetrically with respect to a plane L1 passing through the center of the pair of end faces (short sides) 2e, 2f. The present invention is not limited to this, and the first optical path conversion layer 37 and the second optical path conversion layer 5 ′ combined as shown in FIG. 17 have a pair of end faces (long sides) as shown in FIG. It is good also as what is provided symmetrically about plane L2 which passes through the center of 2c and 2d. In that case, the light sources 1 and 1 'are also arranged along the end faces 2c and 2d.

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

  The shape of the light guide is not particularly limited. For example, there are a parallel planar shape, a wedge-shaped planar shape with gradually changing inclination, a square bar shape having various polygonal cross-sectional shapes, and a cylindrical shape having a circular or elliptical cross section.

1,1 'Light source 1a Blue LED
2 Light guide plate 5, 5 ′ Second optical path conversion layer 10 Diffusing member 11 Reflecting member 30, 31, 33, 34, 35, 36, 37, 39, 40 First optical path conversion layer 60, 61, 62, 63, 64, 65, 66, 67, 70, 71, 80, 81, 83 Light source module

Claims (15)

A light guide that transmits light;
A light source that is optically connected to at least one of the end faces of the light guide and emits light of a specific color toward the inside of the light guide;
A first optical path conversion layer that is provided on one main surface perpendicular to the end face of the light guide and includes a material that converts the wavelength of the light from the light source;
The first optical path conversion layer has one or a plurality of pattern elements arranged along the one main surface, and the first optical path conversion layer has a size greater than the dimension of the pattern element with respect to a light guide direction of the light from the light source. A light source module, wherein a dimension of the pattern element in a direction perpendicular to a light guide direction is short. The light source module according to claim 1,
The light source module, wherein the distribution density of the first optical path conversion layer increases with increasing distance from the end face of the light guide. The light source module according to claim 1,
The pattern element of the first optical path conversion layer is inclined at a gradually increasing inclination angle with respect to a light guide direction of the light from the light source as the distance from the end face of the light guide is increased. Light source module. The light source module according to claim 1, 2, or 3,
The light source module according to claim 1, wherein the pattern element of the first optical path conversion layer extends in an elongated direction along a light guide direction of the light from the light source. In the light source module according to any one of claims 1 to 4,
A second optical path conversion layer that is provided on the one main surface of the light guide and is made of a translucent material that does not include a material that converts the wavelength of the light from the light source, and that guides the light from the light source. Prepared,
In the second optical path conversion layer, the ratio between the intensity of the intrinsic color light and the intensity of the light wavelength-converted by the first optical path conversion layer is substantially constant with respect to the light guide direction of the light from the light source. A light source module characterized by being arranged as follows. The light source module according to any one of claims 1 to 5,
The light source module according to claim 1, wherein the first optical path conversion layer is made of a material that generates light of a complementary color with respect to the intrinsic color by the wavelength conversion. The light source module according to any one of claims 1 to 6,
The light sources are respectively provided on a pair of parallel end faces of the light guide,
The light source module, wherein the first optical path conversion layer has the pattern elements symmetrically with respect to a plane passing through the center of the pair of end faces. The light source module according to claim 7,
The light source module is a light source module, wherein the light guide is a rectangular plate, and the pair of end faces correspond to the long sides of the rectangle. The light source module according to claim 7,
The light guide is a rectangular plate, and the pair of end surfaces correspond to the short sides of the rectangle. A method of manufacturing a light source module for producing the light source module according to any one of claims 1 to 9,
Forming the pattern element of the first optical path conversion layer on the one main surface of the light guide by printing using a mask,
A method of manufacturing a light source module, wherein the light source is attached to the end face of the light guide. A light guide that transmits light;
A light source that is optically connected to at least one of the end faces of the light guide and emits light of a specific color toward the inside of the light guide;
A first optical path conversion layer provided on one main surface perpendicular to the end face of the light guide and including a material for wavelength-converting the light from the light source;
A second optical path conversion layer that is provided on the one main surface of the light guide and is made of a translucent material that does not include a material that converts the wavelength of the light from the light source, and that guides the light from the light source. Prepared,
The second optical path conversion layer has a ratio of the intensity of the intrinsic color light traveling inside the light guide and the intensity of the light wavelength-converted by the first optical path conversion layer to the light from the light source. A light source module, which is arranged so as to be substantially constant with respect to a light guide direction. A method of manufacturing a light source module for producing the light source module according to claim 11,
The pattern element of the first optical path conversion layer is formed by printing using a mask, and the pattern element included in the second optical path conversion layer is formed by printing using a mask,
A method of manufacturing a light source module, wherein the light source is attached to the end face of the light guide. The light source module according to any one of claims 1 to 9 or claim 11,
A light source characterized in that a diffusing member for diffusing light emitted from the other main surface to the outside is disposed opposite to the other main surface opposite to the one main surface of the light guide. module. The light source module according to any one of claims 1 to 9, claim 11 or claim 13,
A light source module, characterized in that a reflecting member is disposed opposite to the one main surface of the light guide so as to reflect light to be emitted from the one main surface to the outside toward the light guide. .   An electronic apparatus comprising the light source module according to any one of claims 1 to 9, claim 11, claim 13, or claim 14.

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