JP2010192269A - Light source module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plane light source which is thin and has highly even intensity. <P>SOLUTION: The light source module includes a light diffusion means 12 on a bottom surface 11C of a light guide 11 of which a cross sectional shape is a triangle. Thereby, luminous flux is emitted in directions of a side surface 11D and side surface 11E of the light guide 11, and the light source module which is thin and has a high light diffusion property can be obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The light source module of the present invention relates to a light source module using a light emitting diode (LED) as a light source, which can be used as a light source for general illumination or a backlight light source of a liquid crystal display device.

  Conventionally, a planar or linear light source module using a linear light guide has been used for general lighting applications, backlights for liquid crystal televisions, scanners, copiers, and the like, which are alternatives to fluorescent lamps. As a linear light source using a light guide, for example, there are those described in JP-A-2002-100224 (Patent Document 1), Special Table 2006-511050 (Patent Document 2), and the like.

  The light source module using the light guide disclosed in the above-mentioned patent document includes a light diffusing means for extracting light to the outside of the light guide and a light source for making the light incident on the light guide. The light emitted from the light source is coupled to the light guide and is guided through the light guide by repeating total reflection. At this time, the light incident on the light diffusing means formed on the light guide is scattered by the light diffusing means as needed, and is emitted to the outside of the light guide at a stage where the total reflection condition is not satisfied.

  Incidentally, in recent years, liquid crystal televisions have been required to be further thinned for reasons such as design, space saving, and resource saving. In addition, in order to reduce the thickness of the entire liquid crystal television, it is essential to reduce the thickness of the backlight. For this reason, it is necessary to emit light with high diffusion from the light source module used for the backlight. For example, when a linear light source module is used as a light source for a backlight of a liquid crystal television, it is desirable to emit light with high diffusion, and it is desirable to further widen the light intensity distribution shown in FIG.

  On the other hand, in the conventional example, this light diffusibility is not considered at all. For this reason, in the structure of a prior art example, the diffusibility of emitted light is inadequate and there exists a problem that the backlight apparatus cannot be reduced in thickness. Also, for general lighting applications, being able to emit light with high diffusion means that it is possible to uniformly illuminate a wider area, which is necessary.

JP 2002-100224 A JP-T 2006-511050

  Therefore, an object of the present invention is to provide a light source module capable of emitting light from a light guide body with high diffusion.

In order to solve the above problems, the light source module of the present invention is:
A light source;
A light guide having at least one incident surface on which light from the light source is incident, and an incident surface adjacent to the incident surface that emits light incident from the incident surface;
In the light source module having a light diffusing means for emitting light propagating through the light guide to the outside on a bottom surface adjacent to the incident surface of the light guide, the light source module has an acute angle with respect to the bottom surface of the light guide. As described above, a side surface is provided. According to the light source module of the present invention, the side surface is provided at an acute angle with respect to the bottom surface, and the light path is converted at the side surface portion, thereby enabling emission with higher light diffusibility.

  In the light source module of one embodiment, the cross-sectional shape perpendicular to the light guide direction of the light guide is a triangle, and preferably, the base of the triangle corresponding to the bottom surface of the light guide and the light guide The angle between the other two sides of the triangle corresponding to the side surface is 45 ° ≦ θ <90 °.

  In one embodiment, the cross-sectional shape perpendicular to the light guide direction of the light guide is a trapezoid.

  According to the light source modules of these inventions, it is possible to emit light with higher diffusion. For this reason, the light source module which can irradiate a light beam in a wide range can be obtained.

  In the planar light source device and the electronic apparatus according to an embodiment, at least one light source module is arranged.

  According to the electronic apparatus of this embodiment, it is possible to realize an electronic apparatus such as an illumination light source including a light source module capable of irradiating a light beam over a wide range and a backlight light source of a liquid crystal display device.

  According to the light source module of the present invention, since the side surface of the light guide is provided at an acute angle with respect to the light bottom surface, the light path of the light guide is converted on the side surface of the light guide. Can be emitted.

It is a figure for demonstrating the outline | summary of the light source module 1 of 1st Embodiment of this invention. It is a figure which shows distribution of the light beam radiate | emitted from the light source module 1 of Embodiment 1 of this invention. It is an arrangement pitch distribution figure showing distribution of arrangement pitch of light diffusion means 12 formed in light guide 11 of a 1st embodiment of the present invention. It is a bottom view which shows distribution of the arrangement pitch of the light-diffusion means 12 formed in the light guide 11 of 1st Embodiment of this invention. It is a schematic block diagram which shows the cross-sectional shape of the light guide 11 used for the light source module 1 of 2nd Embodiment of this invention. It is a figure which shows distribution of the light beam radiate | emitted from the light source module 1 of 2nd Embodiment of this invention. It is a figure for demonstrating the planar light source device 17 in 3rd Embodiment implement | achieved by arranging at least 1 or more of the light source modules 1 of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2. An illumination device using an LED as a light source will be described as an example. Note that the present invention is not limited to the configurations of the following embodiments. Moreover, about the member which shows the same function and effect | action, the same code | symbol is attached | subjected and description is abbreviate | omitted.

(First embodiment)
FIG. 1A is a perspective view of the light guide 11 provided in the first embodiment of the light source module 1 of the present invention, and FIG. 1B is a cross-sectional view showing an AA cross section of the light guide 11.

  In the first embodiment, as an example of the light guide 11, a regular triangular prism acrylic resin having a side of 10 mm and a length of 530 mm is employed. Here, the length is a dimension of the light guide direction Z from the light incident side end surface 11A toward the opposite side end surface 11B of the light incident side end surface 11A, and the height is a direction that is a main emission direction of the light guide 11. Y is the dimension, and the width is the dimension in the direction X perpendicular to the light guide direction Z and the main emission direction Y.

  The size can be changed as necessary and is not limited to the above size. Moreover, as a material of the light guide 11, the same effect can be obtained as long as it is a transparent and high light transmittance material such as polystyrene resin, methacrylic resin, polycarbonate resin or glass in addition to acrylic resin. It is not limited to resin or the like.

  In the light source module 1 of this embodiment, as shown in FIG. 1A, the light source 2 is installed adjacent to the light incident side end face 11A. In this embodiment, the light source 2 is constituted by an LED (light emitting diode).

  A plurality of light diffusing means 12 are formed at a predetermined interval in the light guide direction Z on the bottom surface 11C as the adjacent surface of the end surface A of the light guide 11, and the adjacent surface adjacent to the bottom surface 11C. A side surface 11D and a side surface 11E are inclined by 60 ° with respect to the bottom surface 11C.

  As shown in FIG. 1A, the light diffusing means 12 are dotted in the direction X on the bottom surface 11C.

  In this embodiment, the light diffusing means 12 is formed by mixing diffusing fine particles in a transparent resin and patterning the light guide 11 linearly by a printing technique such as screen printing or offset printing. It was.

  Note that the light diffusing means 12 can have the same effect even when the light diffusing means 12 has a spot shape instead of a linear shape. Further, the light diffusing means 12 may be a microprism instead of the printed diffusing fine particles.

  Further, in place of the light diffusing means 12, a light diffusing means having a shape having an effect of scattering and reflecting light such as a V-shaped groove and a microlens structure may be used.

  When light entering the light guide 11 from the light source 2 and propagating through the light guide 11 enters the light diffusing means 12, the incident light is reflected and scattered by the light diffusing means 12, The light reflection body 11 does not satisfy the total reflection condition, and the reflected and scattered light is emitted from the side surface 11D and the side surface 11E adjacent to the bottom surface 11C provided with the light diffusion means 12 at an acute angle. In the present embodiment, the side surface 11D and the side surface 11E serve as emission surfaces. The side surface 11D and the side surface 11E are adjacent to the light incident side end surface 11A.

  Here, as described above, the light guide 11 provided in the light source module of this embodiment is scattered by the light diffusion means 12 because the XY cross section of the light guide 11 is an equilateral triangle, unlike the conventional example. The light is emitted from the side surface 11D and the side surface 11E. At that time, the light path is changed by the side surface 11D and the side surface 11E and emitted more obliquely upward, so that the light guide 11 is a rectangular parallelepiped and the cross section is rectangular. As a result, light can be emitted with high diffusion.

  The distribution of the light beam emitted from the light source module according to the first embodiment configured as described above will be described with reference to FIG. This figure shows the X-direction orientation distribution of the light emitted from the light source module shown in FIG. 1 (a) in comparison with the prior art and the like, 20 mm in height from the light diffusion means on the bottom surface of the light guide. The result of having obtained | required the illumination intensity distribution on the irradiation surface of the position of by the simulation is shown. The length and height of the base on which the light diffusing means was provided were almost constant, and the influence of the side angle on the orientation distribution was evaluated.

  The thin solid line in FIG. 2 shows the case where the cross-sectional shape of the light guide 11 is an equilateral triangle with a base length of 10 mm in FIG. 1 and θ = 60 °, and the thin broken line shows the cross-sectional shape of the light guide 11 in the length of the base. The case of an isosceles triangle with a thickness of 10 mm and θ = 45 ° is shown, and the thick solid line shows the case where the cross-sectional shape of the light guide 11 is 10 mm at the base of θ = 90 ° and the height is 6 mm. The point where the position of the light guide 11 in the X direction is 0 mm corresponds to the center portion of the light guide 11.

  As can be seen from FIG. 2, the light diffusibility is increased by making θ smaller than 90 °, that is, by making the shape of the light guide 11 into a triangular shape. Further, when θ is 45 ° or less, θ is 90 °, that is, the diffusion state is similar to that in the case where the cross section is rectangular. For this reason, it has been found that the angle θ formed by the bottom surface and the side surface is preferably 45 ° ≦ θ ≦ 90 °.

  Next, the distribution of the arrangement pitch (mm) of the light diffusing means 12 formed in the light guide 11 of this embodiment is shown. 3 represents the position coordinate Z in the Z direction from the light incident side end surface 11A to the opposite side end surface 11B of the light incident side end surface 11A, and the vertical axis in FIG. 3 represents the arrangement pitch of the light diffusion means 12. (mm). In the position coordinate Z, zero represents the center position between the light incident side end face 11A and the opposite end face 11B of the light incident side end face 11A, and the position coordinate Z becomes closer to the opposite end face 11B than the center position. Has increased.

  4 is a view of FIG. 1 viewed from the bottom surface 11C side, that is, in the Y direction. The arrangement pitch of the light diffusing means 12 decreases with increasing distance from the light incident side end face 11A, and the arrangement pitch is minimized on the opposite end face 11B side. That is, the light diffusion means 12 has the maximum density on the light incident side end face 11A.

  The example of the arrangement pitch distribution shown in FIGS. 3 and 4 was obtained by using ray tracing analysis software so that the illuminance distribution on the irradiation surface was uniform. This is because the light source 2 emits light from the inside of the light guide and is not attenuated, so the amount of light is large. However, in the process of guiding light to the opposite side end surface 11B, the light amount is attenuated because it is emitted by the light diffusion means 12. . In order to compensate for the attenuation, the density of the light diffusing means 12 is increased on the end face B side.

  Further, in this embodiment, the light diffusing means 12 is formed in a linear and island shape, the width thereof is constant, and the arrangement pitch distribution, that is, the density is changed, but the width of the linear light diffusing means, that is, You may change the size. Further, the size and density of the spotted light diffusing means may be changed by using the linear light diffusing means as the spotted light diffusing means.

  As described above, the cross-sectional shape perpendicular to the light guide direction of the light guide 11 is a triangle, and the light diffusing means 12 is provided on the bottom surface thereof, so that the light diffusibility is further improved compared to the case where the cross-sectional shape is a rectangle. It becomes possible to do. Moreover, a light source with uniform brightness and illuminance can be obtained by making the pitch and size of the light scattering means variable in the light guide direction.

  As a result, a light source module capable of irradiating a light beam over a wide range can be obtained, and the light source module can be thinned.

(Second embodiment)
Next, a second embodiment of the present invention will be described based on FIG. 5 and FIG.

  FIG. 5 shows a cross-sectional shape of the light guide 11 in the second embodiment. As a schematic configuration of the light source module, only the shape of the light guide 11 is different from that of the first embodiment. In addition, the position of a cross section shows the cross section of the substantially same position as the AA cross section of FIG.

  The shape of the light guide 11 in the second embodiment is trapezoidal, and the angle θ formed by the bottom surface 11C, the side surface 11D, and the side surface 11E is an acute angle. In the second embodiment, light is emitted from the side surface 11D, the side surface 11E, and the upper surface 11F.

  FIG. 6 shows the result of calculating the illuminance distribution on the irradiation surface 20 mm above the bottom surface 11 </ b> C by simulation when the height h of the trapezoidal shape is changed.

  The thin solid line shows the case where θ is 60 ° and h = 6 mm, the thin broken line shows the case where θ is 60 ° and h = 5 mm, and the thick solid line is the case where the cross-sectional shape is rectangular and θ is 90 °. . The length of the bottom of the cross-sectional shape is 10 mm.

  As can be seen from FIG. 6, when the cross-sectional shape of the light guide is trapezoidal, the light diffusibility is inferior to the triangle of the first embodiment because of the influence of the light beam emitted from the upper surface 11F, but the cross-sectional shape is rectangular. Compared to the case, light can be emitted with higher diffusion, and a light source module capable of irradiating a light beam over a wide range can be obtained.

  In the present embodiment, the entrance surface is an end surface (not shown), and the exit surface is a side surface 11D, a side surface 11E, and an upper surface 11F adjacent to the end surface.

(Third embodiment)
Next, an electronic device including the light source module of the present invention will be described with reference to FIG. 7 using a planar light source device as an example.

  FIG. 7A is a plan view of the planar light source device 17 realized by arranging a plurality of light source modules in the first embodiment of the present invention, and FIG. 7B is a cross-sectional view taken along line AA of the planar light source device 17. It is.

  FIG. 7 assumes a backlight for a liquid crystal television as the planar light source device. An optical sheet such as a diffusion sheet 20 is provided on the light emitting side of the light guide 11 in FIG. Furthermore, an optical sheet such as the reflection sheet 21 is provided on the bottom surface side of the light guide 11, that is, in the −Y direction, so that the light use efficiency is improved.

  Since this planar light source device uses the light source module of the present invention and is excellent in light diffusibility, it is possible to obtain a planar light source with uniform brightness by adopting the configuration of the third embodiment. It becomes.

  Further, since the light source module of the present invention is excellent in light diffusibility, it is possible to diffuse light at a wide angle at a low height. When compared with the same light diffusivity, the third embodiment This electronic device can be made thinner than when a plurality of conventional light source modules are arranged.

  In the present embodiment, the light guide 11 is arranged in the vertical direction with respect to the planar light source device 17, but the same effect can be obtained even if arranged in the horizontal direction.

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

DESCRIPTION OF SYMBOLS 1 Light source module 2 Light source 11 Light guide 11A (light guide 11) light incident side end surface 11B (light guide 11) opposing side end surface 11C (light guide 11) bottom 11D (light guide 11) side 11E Side surface (of light guide 11) 11F Upper surface of (light guide 11) 12 Light diffusing means 17 Flat light source device 20 Diffusion sheet 21 Reflecting sheet

Claims (5)

A light source;
At least one incident surface on which light from the light source is incident;
A light guide having an exit surface adjacent to the entrance surface for emitting light incident from the entrance surface;
A light diffusing means for emitting light propagating through the light guide to the outside on a bottom surface adjacent to the incident surface of the light guide;
The light source is characterized in that a side surface is provided at an acute angle with respect to the bottom surface.   The light source module according to claim 1, wherein a cross-sectional shape perpendicular to the light guide direction of the light guide is a triangle.   The light source module according to claim 2, wherein an angle formed by the bottom surface and the side surface is 45 ° ≦ θ <90 °.   The light source module according to claim 1, wherein a cross-sectional shape perpendicular to the light guide direction of the light guide is a trapezoid.   One or more light source modules according to claim 1 are arranged, and a planar light source device and an electronic apparatus are arranged.