JP2011258352A - Light source module and electronic equipment equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce luminance unevenness caused in a jointing portion of a light guide body while installing a fixing part in the light guide body.SOLUTION: The light guide body 21 has a fixing part 21b for fixing the light guide body 21 to a chassis, which is formed thinner than a thick part 21c being a central portion of the cross-section orthogonal to the longitudinal direction of the light guide body 21, at least at one of the side end of the cross-section orthogonal to the longitudinal direction of the light guide body 21; a light scattering body 23 has an arrangement density at the end part of the thick part 21c smaller than the arrangement density in the region other than the end part, along the direction orthogonal to the longitudinal direction of the light guide body 21. Thus, the light guide body 21 can be fixed by the fixing part 21b and the effect of the optical characteristics due to installation of the thin fixing part 21b can be compensated by installation of the light scattering body 23 which is adjusted in the arrangement density in a short-length direction.

Description

  The present invention relates to a light source used in a backlight including a side edge (also referred to as a sidelight) type light guide plate that emits light from a light source in a planar shape by a light guide plate, for example, in a liquid crystal display device. The present invention relates to a module and an electronic device including the module.

  In recent years, in order to reduce the thickness of a liquid crystal display device, a backlight including a side edge (also referred to as a sidelight) type light guide plate that emits light from a light source in a planar shape by a light guide plate is frequently used.

  As such a side edge type light guide plate, for example, there is an illumination device disclosed in Patent Document 1. FIG. 11 is a diagram showing an outline of the configuration of the illumination device disclosed in Patent Document 1. As shown in FIG. The illuminating device 100 disclosed in Patent Document 1 is provided with a light guide plate 110 including a plurality of light guides 111 arranged in a row, and for each light guide 111 of the light guide plate 110, and with respect to the light guide 111. And a plurality of light sources 101 that emit light. The light source 101 includes one red LED (Light Emitting Diode) 101R, two green LEDs 101G, and one blue LED 101B (FIG. 11A). A reflective sheet 102 is provided below the light guide plate 110 (FIG. 11B). And the clearance gap 103 which consists of an air layer of 0.1 micrometer or more is formed between the adjacent light guides 111 (FIG.11 (c)). With this configuration, pseudo-impulse display can be performed.

  For example, Patent Document 2 also discloses the same type of light emitter structure. Further, Patent Document 2 discloses a structure in which reflection dots for changing the direction of light are formed in a printed pattern in which the density is changed in the longitudinal direction of an elongated luminous body (FIG. 12). As shown in FIG. 12, the density of the reflective dots 201 changes from the light input end 215 and the mixing unit 281 to the center of the elongated illuminator. In addition, in order to achieve uniform light extraction and illumination from one end of the light emitter to the other end, the size and shape of the reflective dot 201 is the distance from the mixing unit 281 in addition to the light input end 215. Varying as a function of

JP 2008-34372 A (published February 14, 2008) JP 2009-43706 A (released February 28, 2009)

  In the above conventional configuration, as shown in FIG. 13, the light guides 111... Having a rectangular cross section are sandwiched and fixed between the chassis 2 and the diffusion plate 15. However, since the diffusion plate 15 has low strength, the light guides 111 are not sufficiently fixed. For this reason, the light guides 111 are shifted in position and uneven brightness occurs, or the light guides 111 are in contact with the liquid crystal panel and are damaged.

  Therefore, as shown in FIG. 3 which is an explanatory diagram of the present invention, the light guide 21 is formed in a T-shaped cross section in which thin fixing portions 21b and 21b are provided on both sides of the central thick portion 21c. It is conceivable to fix the light guide 21 by sandwiching the fixing portion 21b and the chassis 2 between the upper presser 52 and the lower presser 51.

  However, since the optical characteristics of the thin fixed portion 21b are different from those of the thick portion 21c, bright lines and dark lines are generated at the joint portions of the light guides 21 and 21 simply by providing the fixed portion 21b for fixing. It is difficult to make the brightness uniform.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a light source module in which a fixing portion is provided in a light guide body and luminance unevenness generated in a joint portion of the light guide body is reduced, and The object is to provide an electronic device equipped with the same.

  In order to solve the above problems, a light source module according to the present invention receives light from a plurality of light guides provided in parallel to the longitudinal direction and at least one end face of the light guide in the longitudinal direction. A plurality of light sources and a plurality of light path conversions provided on the light emission side of the light guide or on the reflection sheet side opposite to the light guide in order to extract the light guided inside the light guide And a chassis for attaching the light guide, wherein the light guide is at least one side end of a cross section perpendicular to the longitudinal direction of the light guide in the longitudinal direction of the light guide. A fixing portion for fixing the light guide to the chassis, which is formed thinner than the thick side portion which is the other side end portion or the central portion of the cross section orthogonal to the optical path conversion portion. Length in light body Along a direction perpendicular to the direction, the arrangement density at the ends of the thick portion is characterized in that less than the arrangement density in the region other than the end portion.

  According to said structure, it becomes possible to fix a light guide to a chassis stably via a fixing | fixed part by providing a thin fixing | fixed part in the side end of a thick part. Therefore, there is no problem that the position of the light guide is shifted and uneven brightness occurs, or that the light guide contacts the liquid crystal panel or the like and is damaged.

  Further, by making the arrangement density of the optical path changing portions at the end portion of the thick portion smaller than the arrangement density in the region other than the end portion, the luminance distribution in the short direction can be made uniform. Therefore, it is possible to provide a light source module capable of stably fixing the light guide and obtaining uniform luminance display.

  In addition, the optical path conversion unit is adjacent to the optical path conversion in the end region from the end of the thick part to the end of the light guide along the direction orthogonal to the longitudinal direction of the light guide. It is desirable that the interval and the size of the parts are smaller than the interval and the size of the adjacent optical path conversion units in the region other than the end region.

  The interval (pitch) and size between adjacent optical path conversion parts in the end region from the end of the thick part to the end of the light guide are made smaller than the pitch and size in other than the end region. Thus, the arrangement density can be varied smoothly. Therefore, the luminance distribution can be made more uniform. Further, it is possible to suppress the influence of printing misalignment, dimensional tolerance of the light guide, and obtain a uniform luminance distribution.

  Moreover, it is desirable that the optical path conversion unit is provided in a region other than a boundary portion between the thick portion and the fixed portion.

  The way the light spreads differs between the thick part and the fixed part. When an optical path changing unit is provided at the boundary between the thick part and the fixed part, light is radiated from both the thick part and the fixed part, so that uneven brightness tends to occur. Therefore, a uniform luminance distribution can be realized by providing the optical path conversion unit in an area other than the boundary part between the thick part and the fixed part.

  Moreover, as for the said light conversion part, it is desirable for the space | interval of the said adjacent optical path conversion parts to be 0.5 mm or more.

  It is assumed that the print pattern which is the optical path conversion unit is misaligned during printing. When a misalignment occurs, if the print pattern that was in the thick part is provided in the fixed part, or conversely, if the print pattern that was in the fixed part is provided in the thick part, light will be transmitted between the thick part and the fixed part. Since the spreading method is different, luminance unevenness is caused. In order to prevent this, it is desirable to leave a distance in the vicinity of the boundary between the thick portion and the fixed portion so that the print pattern does not enter another region when a positional deviation occurs. Accordingly, it is possible to suppress luminance unevenness due to the positional deviation of the print pattern.

  In addition, an electronic apparatus according to the present invention includes the light source module described above.

  According to said structure, while providing a light guide stably, providing an electronic device provided with the light source module which does not generate a bright line or a dark line in the joint part of a light guide, and can reduce brightness irregularity There is an effect that can be.

  In the light source module according to the present invention, the light guide has at least one side end of the cross section orthogonal to the longitudinal direction of the light guide, and the other side end or center of the cross section orthogonal to the longitudinal direction of the light guide. A fixing portion for fixing the light guide to the chassis, the optical path changing portion is formed along the direction perpendicular to the longitudinal direction of the light guide, The arrangement density at the end portion of the thick portion is smaller than the arrangement density in the region other than the end portion.

  An electronic device according to the present invention includes the light source module described above.

  Therefore, it is possible to provide a light source module that can stably fix the light guide and obtain a uniform luminance display, and an electronic device including the light source module.

1 illustrates an embodiment of a light source module according to the present invention, and is a front view illustrating a structure of a light guide that constitutes a light guide plate, a plan view, and an arrangement density distribution of a print pattern that is an optical path conversion unit of the light guide. FIG. It is a perspective view which shows an example of the structure of the light guide in the said light source module. It is sectional drawing which shows the attachment structure of the light guide in the said light source module. It is explanatory drawing about the arrangement | positioning density of the printing pattern of the light-scattering body formed in the light guide shown in FIG. 1, and is a figure which shows the luminance distribution of the transversal direction of the light guide in the light conversion part of each position. . It is the figure which expanded the printing pattern of the fixing | fixed part and thick part vicinity in the light guide shown in FIG. It is explanatory drawing which shows the outline of the structure of the light guide shown in FIG. 1, FIG. It is explanatory drawing which shows the state by which the brightness | luminance was equalized by the light source module provided with the light guide shown in FIG. It is a disassembled perspective view which shows the structure of the liquid crystal display device provided with the said light source module. It is sectional drawing which shows the structure of the principal part in a liquid crystal display device provided with the said light source module. It is a top view which shows the structure of the light-guide plate in the said light source module. (A) is a top view which shows the structure of the conventional light source module, (b) is a front view which shows the structure of the said light source module, (c) is the sectional view on the AA 'line of (a). . It is a top view which shows the structure of the conventional light source module. It is sectional drawing which shows the attachment structure of the light guide in the conventional light source module. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the background of this invention, (a) is about the optical path when light is emitted from a light guide, and the light guide of the cross section which is a curved shape where the front end angle | corner was chamfered about the light guide of a rectangular cross section It is sectional drawing of the light guide which shows the light emission position of the light source in the case of performing a comparative experiment, and (b) is a cross section of the light guide showing the optical path in the light guide having a rectangular cross section where the tip angle is not chamfered. It is a figure and (c) is sectional drawing of the light guide which shows the optical path in the light guide of the cross section which is the curved shape where the front-end | tip angle | corner was chamfered. It is a figure which shows the background of this invention, and is a graph which shows the relationship between the position and brightness | luminance of a light source module provided with the light guide which is the curved shape where the front-end | tip angle | corner in the thick part was chamfered.

  The embodiment of the present invention will be described below with reference to FIGS.

  First, with reference to FIGS. 8-10, the structure of the liquid crystal display device 1 as an electronic device provided with the light source module 10 of this Embodiment is demonstrated, for example.

  As shown in FIG. 8, the liquid crystal display device 1 includes a chassis 2, a light source module 10, a liquid crystal panel 3, and a bezel 4 in order from the bottom. The light source module 10 includes a reflection sheet 11 as a reflection plate. The light source includes an LED (Light Emitting Diode) 12 as a light source and an LED substrate 13, a reflector 14, a light guide plate 20, a diffusion plate 15, and an optical sheet group 16. Note that the optical sheet group 16 may not exist in the present invention.

  As shown in FIG. 9, the LED 12, the LED substrate 13, and the reflector 14 are provided at the end portion of the light guide plate 20, so that the light from the LED 12 is incident on one end face 21 a of the light guide plate 20 and guided. The liquid crystal panel 3 is irradiated with light from the exit surface 21 d of the light plate 20 through the diffusion plate 15 and the optical sheet group 16. Therefore, the light source module 10 of the present embodiment employs a side edge (also referred to as side light) method.

  The diffusing plate 15 may be disposed in close contact with the light emitting surface 21d of the light guide 21 without being spaced, or is provided above the light emitting surface 21d with a space D. Also good. In the case of being provided above the emission surface 21d and the distance D, the luminance unevenness can be reduced as compared with the case where the diffusion plate 15 is in close contact with the emission surface 21d of the light guide 21.

  By the way, the liquid crystal display device 1 has a problem of blurring of moving images as compared with a CRT (Cathode-Ray Tube) display device. That is, in the CRT display device, since there is a non-light emission period in which this pixel does not emit light between the light emission period of the pixel in a certain frame and the light emission period of this pixel in the next frame, there is little afterimage feeling. On the other hand, since the display method of the liquid crystal display device 1 is a “hold type” that does not have such a non-light emitting period, an afterimage feeling is generated, and this afterimage feeling is recognized by the user as blurring of a moving image.

  Therefore, in the backlight type liquid crystal display device 1, the light source module 10 that is a backlight is divided and sequentially turned off in synchronization with the timing of applying the video signal to the liquid crystal panel 3. Backlight blinking, which is a technique for inserting a black display between them, has been proposed. Thereby, pseudo-impulse type display can be realized, and afterimage feeling can be suppressed.

  In order to perform the backlight blinking, the light source module 10 of the present embodiment is configured by dividing the light guide plate 20 by a plurality of light guides 21 as shown in FIG. The bodies 21 are arranged with gaps 22 in parallel with each other in the longitudinal direction. Therefore, in the present embodiment, as shown in FIG. 9, the LED 12 causes light to enter from a thick portion 21 c (FIG. 3) described later on one end surface 21 a in the longitudinal direction of each light guide 21. It has become. In addition, it is not necessarily limited to one end surface 21a, but may be incident from the other end surface in the longitudinal direction, and light may be incident from both one end surface 21a and the other end surface. That is, in the present invention, it is sufficient that light is incident from at least one end face 21a.

  When the light guide plate 20 is divided into a plurality of light guides 21 and arranged in parallel in the longitudinal direction, the clearance 22 is about 1 to 2 mm in consideration of thermal expansion and manufacturing tolerances. is required.

  Next, with reference to FIG. 3, a mounting structure of the light guide 21 in the light source module 10 will be described.

  As shown in FIG. 3, each of the light guides 21 of the light guide plate 20 has a T-shaped cross section in which thin fixed portions 21b and 21b are provided on both sides of a central thick portion 21c. That is, the fixing portion 21b is formed so that the chassis-side surface of the fixing portion 21b is flush with the chassis-side surface of the thick portion 21c. Then, the light guide plate 20 is fixed to the chassis 2 by sandwiching the fixing portion 21 b together with the chassis 2 between the upper presser 52 and the lower presser 51 of the fixture 50.

  As a result, the plurality of light guides 21 can be stably fixed to the chassis 2. Therefore, as in the prior art, it is possible to prevent the occurrence of luminance unevenness due to misalignment or damage due to contact with a liquid crystal panel or the like.

  Furthermore, the detailed shape of the light guide 21 is as follows. The fixing portions 21b and 21b as the side ends facing each other of the adjacent light guides 21 and 21 are formed thinner than the thick portion 21c as the central portion of the cross section perpendicular to the longitudinal direction of the light guide 21. Has been. As a result, the light guide 21 of the present embodiment has a T-shaped cross section with a missing portion 21f on the diffusion plate 15 side at the side end, and is formed thinly with the thick portion 21c formed thick. The fixed portions 21b and 21b.

  The structure of the fixture 50 is not limited to that shown in FIG. 3, and can be arbitrarily selected as long as the fixing portion 21 b is attached directly or indirectly to the chassis 2.

  Further, when the fixing portion 21b is formed so that the chassis side surface of the fixing portion 21b is flush with the chassis side surface of the thick portion 21c, the contact surface between the light guide 21 and the chassis 2 is Although it is preferable to widen, it is not limited to this. That is, as long as the light guide 21 can be fixed to the chassis 2, the position of the fixing portion 21b is arbitrary, and may be positioned closer to the emission surface 21d, for example.

  Next, a configuration for preventing luminance unevenness from occurring at the joint portion of the light guides 21 and 21 by providing the fixing portion 21b will be described.

  The light traveling in the light guide 21 collides with the light scatterer 23 serving as an optical path changing unit, whereby the angle of traveling in the light guide 21 is changed, the total reflection condition is broken, and the light guide 21 from the exit surface 21d. The light exits outside and travels toward the diffusion plate 15. Therefore, the luminance distribution of the emitted light can be controlled depending on where in the light guide 21 the light scatterer 23 is arranged and at what density.

  Below, the printing pattern of the light-scattering body 23 which compensates the change of the optical characteristic by having provided the thin fixing | fixed part 21b is demonstrated.

  In the present embodiment, the light scatterer 23 is formed by, for example, dispersing and scattering light scattering fine particles in a polymer and printing. However, the present invention is not limited to this and may be formed by other methods. For example, a phosphor may be used as the light scattering particle, and the light scattering body 23 may be formed with a fine uneven shape such as a prism. It is also possible to form a pattern by providing a rough surface on the emission side surface or the reflection sheet side surface by blasting or the like.

  Next, a pattern example (printing pattern) of the light scatterer 23 formed on the light guide 21 will be described with reference to FIGS. 1, 2, and 4 to 7.

  1 and 2 are views showing a light guide 21 in which a light scatterer 23 is formed by a printing pattern. As shown in FIG. 1 and FIG. 2, the light guide 21 is formed in a printed pattern shape on the surface of the thick portion 21c and the fixed portions 21b and 21b on the chassis 2 side (hereinafter referred to as a pattern arrangement surface 21p). A scatterer 23 is formed.

  For example, the light guide 21 has a length in the longitudinal direction of 900 to 1600 mm (depending on the size of the light source module), a length in the short direction of 40 to 100 mm (possibly larger), and a central portion. The thickness of the thick portion 21c is 4 mm, the thickness of the fixed portion 21b which is the side end portion is 1 mm, and the length of the fixed portion 21b is 2 mm. Further, in the light guide 21, a groove 21g is formed along the longitudinal direction on the emission surface 21d of the thick portion 21c. The grooves 21g have a pitch of 1 mm and a depth of 0.23 mm (depending on the pitch). Further, a vertical surface is formed between the thick portion 21c and the fixed portion 21b.

  The groove 21g has a function of easily breaking a total reflection condition of light guided inside the light guide 21 and easily taking it out. Moreover, the wide light guide 21 can be formed by forming the groove 21g. In the present embodiment, the shape of the light scatterer 23 is described as a dot, but the shape is not limited to this, and may be a belt shape.

  As shown in FIG. 1, the arrangement of the print patterns is such that the arrangement density (ratio of the print pattern to the unit length in the short direction) is bilaterally symmetrical about the center of the thick portion 21c. Distributed. Further, the arrangement density of the print patterns is substantially uniform in the region (excluding the end portion) of the pattern arrangement surface 21p corresponding to the thick portion 21c. Furthermore, the arrangement density of the print pattern is minimal in the vicinity of the end of the thick portion 21c (in FIG. 1, the region near 5 mm from the boundary between the thick portion 21c and the fixed portion 21b). In the fixed part 21c, the arrangement density of the print pattern increases toward the end part direction (the direction opposite to the thick part 21c) of the fixed part 21b. In this way, by arranging the print pattern in the short direction of the light guide 21, luminance unevenness between the light guides can be reduced and a uniform luminance distribution can be realized.

  Here, with reference to FIG. 4, the determination method of the arrangement of the printing pattern of the light scatterer 23 is demonstrated. 4A is a diagram showing the arrangement of the print pattern of the light scatterer 23, and FIG. 4B is the light scatterer 23 at positions A and B on the pattern arrangement surface 21p of the light guide 21. FIG. It is a schematic diagram which shows the luminance distribution by the reflected light from. The dot diameters of the print patterns arranged at the positions A and B are the same so that the arrangement density of the print patterns is the same.

  As shown in FIG. 4B, since the light scatterer 23 at the position A is in the fixed portion 21b where the light guide 21 is thin, the distance to the diffusion plate 15 is increased, and the luminance distribution is widened. (Dotted line in FIG. 4B). On the other hand, since the light scatterer 23 at the position B is in the thick portion 21c where the light guide 21 is thick, the spread of the distribution is narrower than the luminance distribution at the position A in the fixed portion 21b. The value is increased (solid line in FIG. 4B). The luminance distribution in the short direction is an addition of the luminance distribution due to the reflected light from the print pattern at each position of the light guide including the light scatterers 23 other than the positions A and B.

  Here, the absolute value of the brightness of the reflected light from the light scatterers 23 at the positions A and B can be changed by changing the dot diameter of the light scatterers 23. Since the arrangement density can be changed by changing the dot diameter, the absolute value of the brightness of the reflected light from the light scatterer 23 in a certain region is the arrangement of the light scatterer (print pattern) 23 in the region. It can be changed by changing the density.

  In the example shown in FIG. 4, the print patterns of the light scatterers 23 at the positions A and B have the same dot diameter, but the dot diameter of the light scatterer 23 at the position A is set to the brightness at the position A and the position B. The absolute value of the brightness can be made equal by increasing the ratio with the brightness at.

  Therefore, when the absolute value of the reflected light from the light scatterer 23 in a certain region X is smaller than the absolute value of the reflected light from the light scatterer 23 in another region Y, the light scattering in the region X By increasing the arrangement density of the bodies 23 by the ratio between the absolute value of the luminance in the region X and the absolute value of the luminance in the region Y, the luminance value in the region X and the luminance value in the region Y can be made the same. .

  Therefore, a print pattern as shown in FIG. 1 can be arranged by the following method.

  (1) First, the light scatterers 23 are arranged at each position in the short direction (a pattern is arranged so that the arrangement density is constant).

  (2) Next, the luminance distribution of the reflected light from each light scatterer 23 is acquired. The luminance distribution may be acquired by individually measuring and adding the luminance of the reflected light of each light scatterer 23, or may be acquired by measuring the reflected light of each light scatterer 23 in a lump. Good.

  (3) Thereafter, the acquired luminance distribution is compared with the position of the light guide 21 and the position of the light scatterer 23. When the luminance at a certain location is lower than that at another location (a% lower than the other location), the arrangement density of the light scatterers 23 at the certain location is set to 100 / (100-a ) To be doubled. Further, when the luminance at the certain location is higher than the other locations (when it is higher by b% than the other locations), the arrangement density of the light scatterers 23 at the certain location is set to 100 / (100 + b) of the other locations. To be doubled.

  (4) Further, since the light scatterer 23 does not exist between the light guides 21, the methods (2) and (3) are performed at the end portion of the light guide 21.

  (5) After adjusting the print pattern by the method described above, the luminance distribution of the light scatterer 23 is acquired again. And the printing pattern of arrangement | positioning shown in FIG. 1 can be obtained by repeating the method of (2)-(5).

  As described above, the print pattern arrangement density of the light scatterer 23 is obtained by obtaining the luminance distribution data when the pattern is arranged in a specific portion of the pattern arrangement surface 21p, and the correlation between the distribution of the print pattern arrangement and the luminance distribution. Can be determined.

  In order to create the distribution of the pattern arrangement shown in FIG. 1, the print pattern is formed in a polka dot pattern on the pattern arrangement surface 21 p of the light guide 21. Further, the pattern pitch (interval between adjacent polka dots) and the dot diameter are changed, and the pattern arrangement density varies depending on the region.

  The pattern pitch and the dot diameter are constant in the region (excluding the end) of the pattern arrangement surface 21p corresponding to the thick portion 21c.

  On the other hand, in the vicinity of the boundary between the thick portion 21c and the fixed portion 21b, the print pattern pitch and the dot diameter are both reduced to make the pattern arrangement density different from that of the other regions. This is because, in order to make the luminance uniform, it is particularly important to vary the arrangement density of the patterns of the end portions of the light guide 21. FIG. 5 is an enlarged view of the pattern near the boundary between the thick portion 21c and the fixed portion 21b.

  As shown in FIG. 5, it is preferable to make the print pattern pitch and the dot diameter fine from the vicinity of the boundary between the thick portion 21c and the fixed portion 21b to the end portion of the light guide 21. This is because the arrangement density can be varied smoothly for each region, and the luminance distribution can be made more uniform. In addition, when the print pattern is shifted from a predetermined position of the light guide due to the tolerance of the width of the light guide 21 or the printing deviation of the print pattern, the influence of the lack of the print pattern at the end of the light guide 21 is reduced. It is also possible to do.

  Further, as described above, since the cross section of the light guide plate 21 is different in the thick portion 21c and the fixed portion 21b, the luminance distribution on the diffuser plate due to the light scattered from the patterns before and after it is different. That is, in the fixed portion 21b where the light guide 21 is thin, the luminance distribution is widened because the distance to the diffusion plate 15 is long. On the other hand, in the thick portion 21c where the light guide 21 is thick, the spread of the luminance distribution is narrower and the absolute value of the luminance is larger than the fixed portion 21b. The luminance distribution in the short direction is the sum of the luminance distributions formed by these patterns.

  When arranging the print pattern, as shown in FIG. 5, it is preferable not to arrange the print pattern at the boundary (dotted line portion) between the fixed portion 21b and the thick portion 21c. When the print pattern is arranged at the boundary between the fixed part 21b and the thick part 21c, when the misalignment of the print pattern occurs, the thick part 21c is changed to the fixed part 21b (or conversely, the fixed part 21b is changed to the thick part). 21c), the print pattern is shifted. As a result, the influence on the luminance is greater than when the luminance distribution formed by the print pattern is shifted in the fixed portion 21b (or in the thick portion 21c), which causes luminance unevenness. That is, it becomes weak when a printing misalignment occurs due to a width tolerance or the like.

  Furthermore, it is desirable that the pitch between the printed patterns across the boundary region is 0.5 mm or more apart. This is because, when the printing positional accuracy is ± 0.25 mm, the unevenness in luminance due to the above-described tolerance can be substantially suppressed by arranging the prints at a distance of 0.5 mm or more.

  In the present embodiment, the dot diameter of the light scatterer 23 is, for example, 0.2 to 2.0 mm.

  Here, since brightness | luminance attenuate | damps as it distances from LED12 which is a light source, it is necessary to make arrangement | positioning density of the light-scattering body 23 high as it distances from LED12.

  Therefore, as shown in FIG. 6, the dot diameter of the light scatterer 23 may be increased as the distance from the LED 12 increases along the longitudinal direction. Or you may shorten the dot space | interval of the light-scattering body 23 as it distances from LED12 along a longitudinal direction. 6 shows a case where the light of the LED 12 is incident from both end faces 21a and 21a of the light guide plate 21, the dot diameter of the light scatterer 23 at the center of the light guide plate 21 is large, and the pattern This shows a case in which the arrangement density of is maximum. Further, in FIG. 6, the distribution in the short direction is made uniform so that only the distribution in the longitudinal direction is easily understood.

  Thus, in order to realize the distribution of the print pattern shown in FIG. 1, the print pattern has a dot diameter and a dot of the light scatterer 23C in the vicinity of the position corresponding to the boundary between the thick part 21c and the fixed part 21b. By making at least one of the intervals different from that of the other regions, the pattern distribution density is made different, so that the luminance distribution is made uniform.

  Next, with reference to FIG. 7, in the light source module 10 including the three light guides 21..., The light scatterers 23 are arranged in the print pattern shown in FIG. An example is shown.

  As shown in FIG. 7, when a light scatterer having a uniform pattern with respect to the cross-sectional thickness of the light guide is arranged, about 7% of unevenness was observed in the luminance distribution (broken line). On the other hand, when the light scatterer 23 is arranged with a printing pattern having an optimized arrangement density as shown in FIG. 1 with respect to the cross-sectional thickness of the light guide 21, the unevenness of the luminance distribution is improved. In the luminance distribution, the unevenness is about 1% (solid line).

  As described above, it is possible to make the luminance distribution uniform by changing the arrangement density of the print patterns along the short direction.

  Further, the liquid crystal display device 1 as the electronic apparatus of the present embodiment includes the light source module 10 of the present embodiment. Thereby, the liquid crystal display device 1 provided with the light source module 10 that can reduce the occurrence of uneven brightness can be provided.

[Reason for uneven brightness]
Here, the reason why the luminance unevenness occurs at the joint portion of the light guide will be described with reference to FIGS.

  FIGS. 14A to 14C show a comparison between a light guide having a rectangular cross section and a light guide having a cross section having a curved shape with a chamfered tip angle with respect to an optical path when light is emitted from the light guide. It is a figure explaining experiment.

  First, as shown in FIG. 14A, extracted light when light is emitted from the center of the lower surface of the thick portion 321c of the light guide 321 (or when reflected at the center of the light scatterer 323). Consider the movements.

  First, as shown in FIG. 14B, when the thick portion 321c is formed in a rectangular shape, a part of the light rays falling on the side surface of the thick portion 321c is totally reflected, and the light rays can be extracted from the edge portion. I understand that there is no. As a result, it is clear that the rectangular edge portion of the thick portion 321c is a dark line.

  On the other hand, as shown in FIG. 14C, when the leading end angle of the thick portion 321c of the light guide 321 is a chamfered curved shape, the bottom surface of the thick portion 321c of the light guide 321. It can be seen that the light incident on the chamfered curved shape among the light rays emitted from the central portion is condensed. As a result, the rectangular chamfered portion of the thick portion 321c may become a bright line.

  FIG. 15 is a graph showing the relationship between the position of the light source module including the light guide 321 having a curved shape with a chamfered tip angle at the thick portion 321c and the luminance. The light scatterer 323 has a uniform pattern in the short direction and is formed as a printed pattern on the side of the light guide 321 on the side of the reflection sheet.

  And as shown in FIG. 15, each light guide 321 is a light source having a light scatterer 323 in which the leading end angle of the thick portion 321c is chamfered and a rectangular print pattern is formed in a ladder shape. In the module, it can be seen that bright lines are generated at the joints of the light guide 321.

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

  The present invention relates to a light source module including a side edge (also referred to as a sidelight) type light guide plate that emits light from a light source in a planar shape by a light guide plate, and an electronic device including the light source module. It can be applied to electronic devices such as light source modules and liquid crystal display devices.

1 Liquid crystal display device (electronic equipment)
2 Chassis 10 Light source module 11 Reflective sheet 12 LED (light source)
21 Light guide 21a End surface 21b Fixing part 21c Thick part 21d Emission surface 21g Groove 21p Pattern arrangement surface 23 Light scatterer (light path conversion part)

Claims (5)

A plurality of light guides provided in parallel to the longitudinal direction, a plurality of light sources that allow light to enter from at least one end face in the longitudinal direction of the light guide, and a light guide inside the light guide In a light source module including a plurality of optical path conversion units provided on the light emission side of the light guide, or on the reflection sheet side opposite to the light guide,
The light guide body has at least one side end of a cross section orthogonal to the longitudinal direction of the light guide body, and a thicker portion that is the other side end portion or center portion of the cross section orthogonal to the longitudinal direction of the light guide body. A fixing portion for fixing the light guide to a chassis to which the light guide is attached,
The optical path conversion unit is characterized in that an arrangement density at an end of the thick part is smaller than an arrangement density in a region other than the end along a direction orthogonal to the longitudinal direction of the light guide. Light source module.   The optical path conversion units are adjacent to each other in the end region from the end of the thick part to the end of the light guide along the direction orthogonal to the longitudinal direction of the light guide. 2. The light source module according to claim 1, wherein an interval and a size of the light path module are smaller than an interval and a size of the adjacent optical path conversion units in a region other than the end region.   The light source module according to claim 1, wherein the optical path conversion unit is provided in a region other than a boundary portion between the thick portion and the fixed portion.   4. The light source module according to claim 3, wherein the optical path conversion unit has an interval between adjacent optical path conversion units of 0.5 mm or more.   An electronic apparatus comprising the light source module according to claim 1.