KR100895753B1 - Planar light source device, light guide used for the same, and manufacturing method thereof - Google Patents

Abstract

Even in the case of using a light source reflector with strong specular tendency in the edge light type light source device, the light emitted from the primary light source and entering the light incident cross section and introduced into the light guide is not blocked. However, the occurrence of dark lines due to the shielding of light to be originally guided is prevented, and the generation of bright lines in the vicinity of the light incident cross section over a long period of time is prevented, and the occurrence of a sudden sudden brightness change is prevented. In the light guide 3 used in combination with the primary light source 1 and the light source reflector 2, the first light absorption band 36 postponed to the light exit surface 33 along the light incident end face 31 and The 2nd light absorption band 136 is arrange | positioned in parallel, the width | variety of the 1st light absorption band 36 is 50 micrometers-800 micrometers, and the side edge close to the light incident end surface 31 of the 1st light absorption band 36 is light. The distance from the incident end surface is 300 micrometers or less, and the edge near the light incident end surface 31 of the 2nd light absorption band 136 is 500 micrometers-3000 micrometers apart from the light incident end surface.

Description

A surface light source device and a light guide for use in the same, and a manufacturing method therefor {PLANAR LIGHT SOURCE DEVICE, LIGHT GUIDE USED FOR THE SAME, AND MANUFACTURING METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge light type surface light source device and a light guide used therein, and in particular, a muscle shape according to the light incident cross section near the light guide cross section facing the primary light source. The present invention relates to a surface light source device that is intended to reduce non-uniformity in luminance distribution observed as a bright line and / or a dark line, and a light guide body and a manufacturing method thereof. The surface light source device of the present invention is suitably applied to, for example, a backlight of a liquid crystal display device.

In addition, the present invention relates to a surface light source device particularly for miniaturization and reduced power consumption. The surface light source device of this invention is used suitably for the comparatively small liquid crystal display device used as an indicator of the display panel of portable electronic devices, such as a mobile telephone and a portable game machine, and various apparatuses, for example.

Background Art In recent years, liquid crystal displays have been widely used in monitors, such as portable notebook computers, or as display units such as liquid crystal televisions and video integrated liquid crystal televisions, and in other various fields. The liquid crystal display device basically comprises a backlight unit and a liquid crystal display element unit. As the backlight unit, an edge light method is often used in view of the compactness of the liquid crystal display device. Conventionally, as an edge light type backlight, at least one cross section of a rectangular light guide is used as a light incident cross section, and a linear or rod-shaped primary light source such as a straight tube fluorescent lamp is arranged in accordance with the light incident cross section. Then, the light generated from the primary light source is introduced from the light incident end face of the light guide into the light guide, and the light emitted from one of the two main surfaces of the light guide is emitted widely.

In such a backlight, a nonuniformity may arise (a brightness uniformity falls) due to the propagation form of the light emitted from the primary light source and exiting through the light guide body. As one form of this luminance uniformity fall, the luminance of the region close to the primary light source is higher than that of the other regions.

As a method for preventing such luminance uniformity decrease, for example, Japanese Utility Model Publication No. 1965-26083 (Patent Document 1), Japanese Utility Model Publication No. 1985-60788 (Patent Document 2) and Japanese Utility Model Publication Japanese Patent Laid-Open No. 1987-154422 (Patent Document 3) discloses disposing a light absorbing film or a light adjusting film for suppressing light transmission at a position close to a primary light source of a light emitting surface of a light guide. This technique is to cope with that the intensity of the light emitted from the light guide surface in the region close to the primary light source is greater than the intensity of the light emitted in the region far from the primary light source. It is trying to limit the light output.

By the way, as the thickness of the light guide becomes thinner (for example, about 2 to 3 mm) in recent years, it is a special form of the decrease in the brightness uniformity, and is close to the light incident cross section of the light guide (for example, about 2 to 4 mm). Correspondingly to the light exit plane position, the root (bright line) of the root shape brighter than the periphery may be observed in parallel with the light incident end surface. When the method similar to the said patent documents 1-3 is used for prevention of the locally abrupt brightness change (namely, a big brightness change corresponding to a small position change in a brightness distribution) by this bright line, Since the width | variety of a light absorption film etc. is wide, the problem that a brightness | luminance of not only a bright line but the whole surroundings fall, or a dark line becomes easy to produce arises.

On the other hand, as a technique for preventing a sudden sudden change in luminance due to such bright lines, Japanese Unexamined Patent Application Publication No. 1997-197404 (Patent Document 4) discloses a light exit surface of the light incident cross section of the light guide and an opposite surface thereof. It is proposed to attach a light blocking member such as ink to an edge which forms a boundary with the ink.

In addition, in accordance with the locally abrupt change in luminance due to the above-described generation of bright lines, dark dark portions (dark lines) of darker shapes than the surroundings may be observed between adjacent bright lines in parallel with the light incident cross section. Japanese Patent Application Laid-Open No. 1996-227074 (Patent Document 5) discloses a method for preventing the occurrence of such dark lines, which forms a light absorption layer having a light absorption pattern in which the light absorption rate gradually decreases as it moves away from the light incident end. Is disclosed.

By the way, with respect to liquid crystal display devices having a relatively small screen size, such as portable electronic devices such as mobile phones and portable game machines, or indicators of various electric devices or electronic devices, reduction in power consumption and reduction of power consumption are desired. There, a light emitting diode (LED) which is a point-shaped light source is used as a primary light source of a backlight because of power consumption reduction. As a backlight which used LED as a primary light source, in order to exhibit the same function as using a linear primary light source, for example, as described in Unexamined-Japanese-Patent No. 1995-270624 (patent document 6), A plurality of LEDs are arranged in one dimension according to the light incident cross section of the light guide. Thus, by using the primary light source by the one-dimensional arrangement of several LED, the required light quantity and the uniformity of the brightness distribution over the whole screen can be obtained.

In the case of such a small liquid crystal display device, further reduction in power consumption is required, and in order to respond to this, it is necessary to reduce the number of LEDs used. However, if the number of LEDs is reduced, the distance between the light emitting points increases, so that the area of the light guide close to the area between adjacent light emitting points is enlarged, and the brightness of light emitted from the light guide area in the required direction is reduced. . This brings about unevenness (i.e., luminance unevenness) of the luminance distribution in the viewing direction on the plane of the surface light source device.

In addition, Japanese Patent Application Laid-Open No. 1995-27137 (Patent Document 7) discloses a prism sheet in which a light emitting surface uses a light guide having a rough surface, and a plurality of prism rows are arranged so that the prism face is the light guide side. The method of arrange | positioning on the light emission surface of a sieve, narrowing the distribution of emitted light is proposed in order to suppress the power consumption of a backlight, and to not sacrifice a brightness largely. However, in such a backlight, although high luminance can be obtained with low power consumption, there is a problem that luminance unevenness is easily seen through the prism sheet.

Of these luminance spots, the most significant problem is the dark shadow that occurs in the middle of the light guide body or the adjacent LED 2 corresponding to the outside of the LEDs 2 at both ends in the plurality of LED arrangements as shown in FIG. It is a part (dark part). If the area of this dark part is large and it is made visible also in the effective light emission area | region of the backlight corresponding to the display screen of a liquid crystal display device, a backlight quality will fall significantly. In particular, when the distance between the LED and the effective light emitting area is reduced in order to reduce the number of LEDs used in order to reduce power consumption or to reduce the size of the device, the dark portion is visually recognized in the effective light emitting area. Easier The cause of the luminance unevenness is that the light generated from each of the LEDs disposed adjacent to the light incident end face of the light guide has directivity, and the light incident on the light guide due to the refraction effect when it enters the light guide is This is because the expansion becomes relatively narrow. Further, since only the light in the direction substantially perpendicular to the direction of the prism row of the prism sheet is observed from the normal direction of the light exit surface, the magnification of the observed light is actually smaller than the magnification of the light emitted from the light guide. Thus, with the conventional backlight which uses a point light source as a primary light source, it was difficult to make both the reduction of power consumption and the maintenance of the uniformity of luminance distribution compatible.

Further, in a backlight using a linear light source such as a cold cathode tube as the primary light source, as a method of eliminating the dark portion in the vicinity of the incident surface, for example, Japanese Patent Laid-Open No. 1997-160035 (Patent Document 8) discloses a light guide. Although the method of roughening the light incident cross section of is proposed, in the backlight which used point light sources, such as LED, as a primary light source, such a dark part could not be fully eliminated by this method.

On the other hand, Japanese Utility Model Publication No. 1993-6401 (Patent Document 9) and Japanese Patent Publication No. 1996-179322 (Patent Document 10) or the like have a light guide in a backlight using a linear light source such as a cold cathode tube. For the purpose of converging the outgoing light from the light incidence plane in parallel with the light incidence plane, a plurality of prismatic rows extending along a direction substantially perpendicular to the light incidence cross section are formed in parallel to the light outgoing plane of the light guide or vice versa. Proposed. In the light guide member formed with such a prism row, the light incident on the light guide member is directed to the direction in which the inclination angle with respect to the direction of the incident light increases by reflection of the prism row of the light guide member, or is returned to the direction toward which the incident light is directed. For this reason, since the advancing direction of the light incident on the light guide is converged in the direction in which the prism rows extend, the luminance can be improved. When such a light guide is applied to a backlight using an LED, the light incident on the light guide is enlarged with respect to the direction of the incident light by reflection in the prism row of the light guide, and the enlarged light is approximately equal to the prism row of the prism sheet. Since it exits in the vertical direction, the distribution of the light seen through the prism sheet is expanded.

However, if a prism row having a straight section having a cross-sectional shape is formed in the light guide member, the light can be enlarged by having anisotropy in a specific direction by the prism row, so that a bright muscle shape in the oblique direction as shown in Fig. 74 is formed. Luminance spots occur. In addition, as shown in Fig. 75, the occurrence of luminance unevenness is found by increasing the luminance at the portion where the light emitted from each point light source overlaps each other.

In addition, in order to eliminate the dark areas between the primary light sources and the corners, as described above, when the light incident cross section is roughened, the dark areas become smaller, but the luminance of the near shape bright in the oblique direction as shown in FIG. 76. The stain will be more noticeable.

In order to eliminate such luminance unevenness, Japanese Patent Laid-Open No. 2004-6326 (Patent Document 11) discloses that the surface of the prism row formed on the light guide is roughened, or a lens row is formed in which the linear shape of the prism row is deformed. Is proposed. However, also in the surface light source device using such a light guide body, each point shape as shown in FIG. 76 depending on the magnitude | size of a surface light source device, the number of point shape light sources, such as LED to arrange | position, and the space | interval of arrangement of a point shape light source. Remarkable luminance unevenness due to superposition of bright uneven luminance unevenness in the oblique direction of the light emitted from the light source may be found within the effective display range.

Patent Document 1: Japanese Utility Model Publication No. 1965-26083

Patent Document 2: Japanese Utility Model Publication No. 1985-60788

Patent Document 3: Japanese Utility Model Publication No. 1987-154422

Patent Document 4: Japanese Patent Laid-Open No. 1997-197404

Patent Document 5: Japanese Patent Application Laid-Open No. 1996-227074

Patent Document 6: Japanese Patent Application Laid-Open No. 1995-270624

Patent Document 7: Japanese Patent Publication No. 1995-27137

Patent Document 8: Japanese Patent Application Laid-Open No. 1997-160035

Patent Document 9: Japanese Utility Model Publication No. 1993-6401

Patent Document 10: Japanese Patent Application Laid-Open No. 1996-179322

Patent Document 11: Japanese Patent Application Laid-Open No. 2004-6326

The method of the said patent document 4 attaches a light shielding member to the edge of a light-guide light incident cross section, and since a part of this light shielding member also hangs in a light incidence cross section, a part of the light incident from the light incident cross section will be interrupted | blocked, Since the amount of light incident on the light guide from the primary light source decreases as much as that portion, the overall luminance is easily lowered, and the light to be guided is also shielded if there is no light shielding member among the light incident from the edge. This has a problem of being easy to occur.

Moreover, since this method forms a very narrow light-shielding member, it cannot be said that the effect of suppressing the generation of bright lines is also sufficient. In addition, this technique is very difficult to realize in fact that the light-shielding member is applied to the edge, and it is difficult to form the light-shielding member at a desired position, and the problem that the light-shielding member attached to the edge is likely to fall off is difficult. have.

In addition, in the method of the said patent document 5, although patterns, such as a dot pattern, are employ | adopted as a light absorption pattern, in this case, the area | region which does not absorb light exists in part, and since the light-shielding in this area becomes inadequate, There is a problem such that a bright line is observed.

In the backlight of the edge light system, a light source reflector is used to efficiently introduce light generated from the primary light source into the light guide body. The light source reflector is a reflecting member disposed adjacent to a portion except for a portion facing the light guide body light incident end face of the primary light source, and specifically, a sheet or film is used.

Some light source reflectors have a strong tendency for diffuse reflection and a strong tendency for specular reflection. The light source reflector with a strong tendency to diffuse reflection tends to have a low reflectance, a large number of multiple reflections inside the light source reflector, and a low light incident efficiency to the light guide, as compared with a strong specular tendency to reflect. On the other hand, specular reflection is a reflection form in which there is little reflection component of the light which has diffusivity, and contains many reflection components with high directivity by specular reflection. Therefore, since the light source reflector having a strong tendency for specular reflection tends to have a high reflectance and a high light incident efficiency to the light guide, as compared with a strong diffuse reflection tendency, it is possible to increase the brightness of the backlight (a few% to 15%). There is an advantage. As a light source reflector with a strong tendency for specular reflection, for example, a stainless steel reflector includes a coating reflector, an aluminum reflector, a thick reflective aluminum (multilayer film) reflector, and the like.

By the way, when using the light source reflector with a strong tendency for specular reflection, it turned out that the bright line of the vicinity of the said light-guide light-injection cross section appears especially stronger than when using the light source reflector with a strong tendency to diffuse reflection. Therefore, in this case, it is particularly preferable to prevent the sudden sudden change in luminance that generates bright lines so as not to impair the quality of the backlight.

DISCLOSURE OF THE INVENTION An object of the present invention is to solve the above technical problem, and it is necessary to lower the overall luminance or to guide the light without the light coming from the primary light source entering the light incident cross section and being introduced into the light guide. It is possible to prevent the generation of dark lines in the vicinity of the light incident cross section over a long period of time without causing the generation of dark lines by shielding the light to be prevented, and to prevent the occurrence of a sudden sharp brightness change locally.

In particular, the present invention focuses on achieving the above object even when using a light source reflector having a strong tendency of regular reflection in combination with a primary light source in an edge light type light source device.

It is also an object of the present invention to eliminate various luminance unevenness of the surface light source device as described above, and to provide a high quality surface light source device and a light guide for the surface light source device used therefor.

In addition, another object of the present invention is to provide a method advantageous for manufacturing a light guide for a surface light source device that can solve the above technical problems.

According to the present invention, to solve the above technical problem,

In the light guide body which guides the light which generate | occur | produces the light emitted from a primary light source, and has the light incident end surface into which the light emitted from the said primary light source enters, the light exit surface which the light guided out, and the surface opposite to the said light exit surface,

On either of the light exit surface and the surface, the first light absorption band and the second light absorption band extending along the light incident end face are arranged in parallel in this order from the side close to the light incident end face, and the first light absorption band Has a width of 50 μm to 800 μm, and a side edge close to the light incident end face of the first light absorption band has a distance from the light incident end face of 300 μm or less, and is close to the light incident end face of the second light absorption band. A side light guide is provided with a light guide for a surface light source device, wherein the light guide is positioned 500 μm to 30 μm away from the light incident end surface.

In one aspect of the present invention, the visible light transmittance of the second light absorption band is higher than the visible light transmittance of the first light absorption band. In one aspect of the present invention, an edge portion that forms a boundary between the light exit surface and the light incident end surface is formed along the light incident end surface as a protruding portion protruding from another region of the light exit surface. The height half width of the protrusions is 1 to 50 µm.

In addition, according to the present invention, to solve the above technical problem,

In the method of manufacturing the light guide for a surface light source device as described above, by discharging ink from a plurality of nozzles by the inkjet method, they are independent of each other in a region close to at least the light incident end face of the light exit surface of the light guide, Or forming a partially continuous ink dot, and then leveling the ink dots to join adjacent ones to form a continuous ink layer over the entire area, and then curing the ink layer by A manufacturing method of a light guide for a surface light source device is provided, wherein the first light absorption band and / or the second light absorption band are formed.

In one aspect of the present invention, the light incident end face corresponding portion of the light guide member is cut to form the light incident end face, and then the first light absorption band is formed.

In addition, according to the present invention, to solve the above technical problem,

The light guide for a surface light source device as described above, the said primary light source arrange | positioned adjacent to the said light incidence end surface of this light guide, and the optical deflecting element arrange | positioned adjacent to the light exit surface of the said light guide, Comprising: The deflection element has a light incidence surface positioned opposite to the light exit surface of the light guide and an outgoing surface on the opposite side, and is in a direction substantially parallel to the light incident end surface of the light guide on the light incidence surface of the light deflection element. A planar light source device is provided, comprising a plurality of rows of prisms extending and parallel to each other.

In one aspect of the present invention, a light diffusing element is disposed adjacent to a light exit surface of the light deflecting element, and the light diffusing element includes a position of at least 2 mm to a position of 4 mm from a light incident end surface of the light guide. The dot pattern part which provided the light absorption dot pattern in the width | variety of the width | variety is provided, and this dot pattern part is formed by disperse | distributing the light-absorbing ceramic material of the dot shape of 30 micrometers-70 micrometers in diameter.

In addition, according to the present invention, to solve the above technical problem,

In the light guide body which guides the light which generate | occur | produces the light emitted from a primary light source, and has the light incident end surface into which the light emitted from the said primary light source injects, and the light exit surface from which the light guided out, and the back surface opposite to the said light exit surface,

A light absorption band having a width of 50 μm to 1000 μm extending along the light incident cross section is formed on the back surface, and the side edge close to the light incident cross section of the light absorption band has a distance of 300 μm or less from the light incident cross section. A light guide for a surface light source device is provided.

In one aspect of the present invention, an edge portion forming a boundary between the back surface and the light incident end surface is formed along the light incident end surface as a protrusion raised to another region of the back surface, and the height of the protrusion is half the value. Full width is 1-50 micrometers. In one aspect of the present invention, the surface is formed with a prism row forming surface region having a plurality of prism rows extending in a direction substantially perpendicular to the light incident end surface and arranged in parallel with each other, An approximately flat surface region extending along the light incident cross section is formed, and at least a portion of the light absorption band is located at at least a portion of the approximately flat surface region. In one aspect of the present invention, the light absorption band is formed so that the visible light transmittance is higher on the side edge farther than the side edge close to the light incident end face. In one aspect of the present invention, the width of the light absorption band is 50 μm to 800 μm, and on the rear surface of the light absorption band, a second light absorption band extending along the light incidence cross section at a position farther from the light incidence cross section. It is formed, and the side edge close to the light incidence end face of the second light absorption band is positioned 500 mu m to 3000 mu m away from the light incidence end face. In one aspect of the present invention, the visible light transmittance of the second light absorption band is higher than the visible light transmittance of the light absorption band.

In addition, according to the present invention, to solve the above technical problem,

In the light guide body which guides the light which generate | occur | produces the light emitted from a primary light source, and has the light incident end surface into which the light emitted from the said primary light source injects, and the light exit surface from which the light guided out, and the back surface opposite to the said light exit surface,

The light emitting surface or the rear surface is formed with a prism row forming surface area having a plurality of prism rows extending in a direction substantially perpendicular to the light incident end surface and arranged in parallel with each other, and the prism row forming surface area being An approximately flat surface region extending along the light incident cross section is formed on the formed light exit surface or the rear surface, and light having a width of 50 μm to 1000 μm extending along the light incident cross section on at least a portion of the approximately flat surface region. A light guide for a surface light source device is provided, wherein an absorption band is formed.

In addition, according to the present invention, in order to solve the above technical problem, in the method for manufacturing the light guide for a surface light source device, the light incident end surface corresponding to the light incident end surface corresponding portion of the light guide material is cut to perform the light incident There is provided a method of manufacturing a light guide for a surface light source device, wherein a cross section is formed and then the light absorption band is formed.

In one aspect of the present invention, ink is ejected from a plurality of nozzles by an inkjet method to form ink dots that are independent of each other or partially continuous in a region adjacent to at least the light incident end surface of the rear surface of the light guide body, Next, the ink dots are leveled to join adjacent ones to form a continuous ink layer over the entire area, and then the light absorbing band is formed by curing the ink layer.

In addition, according to the present invention, to solve the above technical problem,

And a primary light source disposed adjacent to the light incident end surface of the light guide, and a light deflecting element disposed adjacent to the light exit surface of the light guide. The deflection element has a light incidence surface positioned opposite to the light exit surface of the light guide and an outgoing surface on the opposite side, and extends in a direction substantially parallel to the light incident end face of the light guide on the light incidence surface of the light deflection element. And a plurality of prism rows parallel to each other.

In one aspect of the present invention, a light diffusing element is disposed adjacent to the light exit surface of the light deflecting element, and the light diffusing element includes at least 2 mm to a position of 4 mm from a light incident end surface of the light guide. The dot pattern part which provided the light absorption dot pattern in the width | variety of the width | variety is provided, and this dot pattern part is formed by disperse | distributing the light-absorbing ceramic material of the dot shape of 30 micrometers-70 micrometers in diameter.

Furthermore, the light guide for surface light source devices of this invention guides the light which generate | occur | produces from a primary light source, and also has the plate which has the light-incidence cross section into which the light emitted from the said primary light source enters, and the light exit surface from which the light guided out is emitted. In the light guide of the shape, one of the light emitting surface and the back surface on the opposite side thereof extends substantially along the direction of directivity of light incident on the light guide in the plane along the light emitting surface, and is substantially parallel to each other. A plurality of uneven structure rows arranged are formed, and a band-like flat portion extending along the light incidence end face to at least a portion of a region from the region adjacent to the light incidence end face to the effective light emission region of the uneven structure heat forming surface. It is characterized by being formed.

In addition, the surface light source device of the present invention includes a light guide for a surface light source device as described above, a plurality of point-shaped primary light sources disposed adjacent to the light incident end surface of the light guide, and a light exit surface of the light guide. A light incident surface disposed opposite to the light exit surface of the light guide and opposite to the light exit surface, the light exit surface extending in a direction substantially parallel to the light incident end surface of the light guide; And an optical deflection element in which a plurality of lens rows parallel to each other are formed.

Effects of the Invention

According to the present invention as described above, the first light absorption band having a specific width extending along the light incidence end face at a position near the light incidence end face is formed on the light exit face of the light guide, and the light comes from the primary light source. The light incident from the incidence cross section is not blocked and there is no reduction in the amount of light incident from the primary light source into the light guide, i.e. without lowering the overall brightness or causing the generation of dark lines by shielding the light to be originally guided. The generation of bright lines in the vicinity of the light incident end face can be prevented.

In addition, according to the present invention, the second light absorption band is formed on the light exit surface of the light guide at a predetermined distance from the first light absorption band, and is used in combination with the primary light source when a light source reflector having a strong tendency for specular reflection is used. Also, it is possible to satisfactorily prevent the generation of bright lines in the vicinity of the light incident cross section, and to prevent the occurrence of suddenly sharp brightness changes.

Further, according to the present invention, since the first light absorption band and the second light absorption band are formed on either the light exit surface or the rear surface of the light guide, the fabrication is easy and the formed first and second light absorption bands are easy. Preferably, it is possible to exert the effects of preventing the occurrence of the bright line and preventing the occurrence of the sudden sudden change in brightness over a long period without falling off.

Further, according to the present invention, ink dots are formed on the light exit surface of the light guide by the inkjet method, and then the ink dots are leveled to similarly increase the size of the ink dots, and the ink non-arrival portion is formed by ink. Since the first light absorption band is formed by forming a very continuous ink layer and then curing the ink layer, the bonding state of the ink dots in the ink layer is controlled by setting the required leveling time according to the viscosity of the ink. The surface state of the first light absorption band can be easily controlled.

In addition, according to the present invention as described above, a light absorption band having a specific width extending along the light incident cross section at a position close to the light incident cross section is formed on the back surface of the light guide, and comes from the primary light source and crosses the light incident cross section. The light incident from the block is not blocked and there is no reduction in the amount of light incident on the light guide from the primary light source, i.e. without causing the occurrence of dark lines by reducing the overall brightness or shielding the light to be originally guided, Generation of bright lines in the vicinity of the light incident cross section can be prevented.

Further, according to the present invention, since the light absorption band is formed on the back surface of the light guide, the fabrication of the light absorption band is easy, and the formed light absorption band is not easily eliminated, and it is possible to satisfactorily prevent the occurrence of the above-mentioned bright lines and rapidly abruptly over the long term. It is possible to exert the effect of preventing the occurrence of the luminance change.

In addition, according to the present invention, by cutting the light incident end face corresponding portion of the light guide material and forming the light incident end face, the edge portion forming the boundary between the back face and the light incident end face is placed on the other area of the back face. It can be formed along the light incidence end face as a raised protrusion, and when forming the light absorption band thereafter, the distance from the light incidence end face of the side edge close to the light incidence end face of the light absorption band can be easily 0 mu m.

Further, according to the present invention, ink dots are formed on the light exit surface of the light guide by the inkjet method, and then the ink dots are leveled to similarly increase the size of the ink dots, and the ink non-arrival portion is formed by ink. Since the light absorption band is formed by burying the continuous ink layer and curing the ink layer thereafter, the bonding state of the ink dots in the ink layer can be easily controlled by setting the required leveling time according to the viscosity of the ink. It is possible to control the surface state of the light absorption band, and the distance from the light entrance end face of the side edge close to the light entrance end face of the light absorption band can be easily 0 占 퐉.

Further, according to the present invention, the second light absorption band is formed on the rear surface of the light guide at a predetermined distance away from the light absorption band, so that even in the case of using a light source reflector with a strong tendency for specular reflection in combination with the primary light source, The generation of bright lines in the vicinity of the incident cross section can be prevented, and the occurrence of a sudden sudden change in luminance can be effectively prevented.

According to the present invention, the luminance unevenness of the surface light source device can be eliminated, and a high quality surface light source device can be provided, and in particular, it is relatively used as an indicator of display panels and various devices of portable electronic devices such as mobile phones and portable game machines. The surface light source device suitable for a small liquid crystal display device can be provided.

1 is a schematic perspective view showing an embodiment of a surface light source device according to the present invention;

2 is a schematic plan view showing a light guide with a primary light source,

3 is a view for explaining an example of the manufacturing method of the light guide according to the present invention;

4 is a view for explaining an example of the manufacturing method of the light guide according to the present invention;

5 is a view showing the shape of optical deflection by the optical deflection element;

6 is a schematic plan view showing a light diffusing element together with a primary light source;

Fig. 7 is a schematic partial sectional view of a liquid crystal display device having the surface light source device according to the present invention as a backlight;

8 is a schematic partial cross-sectional view of a light guide;

9 is a schematic partial sectional view of a light guide;

10 shows visible light transmittance of a light guide and a light absorption band;

11 is a view showing visible light transmittance of a light guide and a light absorption band;

12 is an explanatory diagram illustrating an example of a method of manufacturing a light guide;

13 is an explanatory diagram illustrating an example of a method of manufacturing a light guide;

14 is an explanatory diagram illustrating an example of a method of manufacturing a light guide;

15 is a partial cross-sectional view of the light guide;

16 is an enlarged view of an edge portion of the light guide;

17 is an enlarged view of an edge portion of the light guide;

18 is an enlarged view of an edge portion of the light guide,

19 is a schematic perspective view showing one embodiment of the surface light source device according to the present invention;

20 is a schematic plan view showing the light guide with a primary light source,

21 is a view illustrating an example of a method of manufacturing a light guide according to the present invention;

22 is a view for explaining an example of the manufacturing method of the light guide according to the present invention;

Fig. 23 is a schematic partial sectional view of a liquid crystal display device having the surface light source device according to the present invention as a backlight;

24 is a schematic partial cross-sectional view of a light guide;

25 is a schematic partial sectional view of a light guide;

26 is a view showing visible light transmittance of a light guide and a light absorption band;

27 shows visible light transmittance of a light guide and a light absorption band;

28 is an explanatory diagram illustrating an example of a method of manufacturing a light guide;

29 is an explanatory diagram illustrating an example of a method of manufacturing a light guide;

30 is an explanatory diagram illustrating an example of a method of manufacturing a light guide;

31 is a partial cross-sectional view of a light guide;

32 is an enlarged view of an edge portion of the light guide;

33 is an enlarged view of an edge portion of the light guide,

34 is a schematic perspective view showing one embodiment of the surface light source device according to the present invention;

35 is a schematic partial perspective view illustrating the light guide with a primary light source;

36 is a schematic partial bottom view showing a light guide;

37 is a schematic perspective view showing one embodiment of the surface light source device according to the present invention;

38 is a schematic bottom view showing the light guide with a primary light source;

39 is a view for explaining an example of a method for manufacturing a light guide according to the present invention;

40 is a view for explaining an example of a method of manufacturing a light guide according to the present invention;

Fig. 41 is a schematic partial sectional view of a liquid crystal display device using the surface light source device as a backlight according to the present invention;

42 shows visible light transmittance of a light guide and a light absorption band;

43 is a view showing visible light transmittance of a light guide and a light absorption band;

44 is an explanatory diagram showing an example of a method of manufacturing a light guide;

45 is an explanatory diagram illustrating an example of a method of manufacturing a light guide;

46 is an explanatory diagram illustrating an example of a method of manufacturing a light guide;

47 is a schematic partial bottom view showing a light guide;

48 is a schematic partial perspective view showing a light guide;

Fig. 49 is a schematic partial sectional view of a liquid crystal display device using the surface light source device as a backlight according to the present invention;

50 is an exploded perspective view showing the surface light source device according to the present invention;

51 is a bottom view showing the light guide according to the present invention together with the primary light source;

52 is a view showing the shape of optical deflection by the optical deflection element;

53 is a perspective view showing a light guide according to the present invention with a primary light source,

54 is a bottom view illustrating the light guide according to the present invention with a primary light source;

Fig. 55 is an explanatory diagram of a calculation method of the frequency distribution of the inclination angle for specifying the cross-sectional shape of the lens rows of the light guide according to the present invention;

56 shows an example of the frequency distribution of an inclination angle;

Fig. 57 is an explanatory view of a calculation method of the frequency distribution of the inclination angle for specifying the cross-sectional shape of the asymmetric lens row of the light guide according to the present invention;

Fig. 58 is an explanatory diagram of a calculation method of the frequency distribution of the inclination angle for specifying the cross-sectional shape of the irregular concave-convex structure column of the light guide according to the present invention;

Fig. 59 is a schematic plan view showing a method for measuring the normal luminance distribution of the surface light source device according to the present invention;

60 is a diagram illustrating an example of a normal luminance distribution;

61 is a view showing an example of a luminance distribution based on the use of a plurality of primary light sources;

62 is a view showing an example of a cross-sectional shape of lens rows of the light guide according to the present invention;

63 is a view showing an example of a cross-sectional shape of a lens column of the light guide according to the present invention;

64 is a view showing an example of a cross-sectional shape of lens rows of the light guide according to the present invention;

65 is a view showing an example of a cross-sectional shape of a lens column of the light guide according to the present invention;

66 is a view showing an example of a cross-sectional shape of a lens column of the light guide according to the present invention;

67 is a plan view showing the light guide according to the present invention together with the primary light source;

68 is a plan view showing a light guide according to the present invention together with a primary light source;

69 is a partially exploded perspective view showing the light guide according to the present invention together with a primary light source;

70 is an explanatory diagram of a method for manufacturing a light emitting surface forming die of the light guide according to the present invention;

71 is an explanatory diagram of a manufacturing method of a light emitting surface forming die of the light guide according to the present invention;

72 is an explanatory diagram of a method for manufacturing a light emitting surface forming die of the light guide according to the present invention;

73 is a schematic diagram for explaining occurrence of luminance unevenness in the surface light source device;

74 is a schematic diagram for explaining occurrence of luminance unevenness in the surface light source device;

75 is a schematic diagram for explaining occurrence of luminance unevenness in the surface light source device;

76 is a schematic diagram for explaining occurrence of luminance unevenness in the surface light source device;

Explanation of the sign

DESCRIPTION OF SYMBOLS 1 Primary light source, 2: Light source reflector, 3: Light guide, 3 ': Light guide material, 31: Light incident cross section, 31': Light incident cross section corresponding part, 32: Side cross section, 33: Light exit surface, 33 ' : Light exit surface corresponding part, 34: back side, 34 ': back side counterpart, 36, 236: light absorption band (1st light absorption band), 36-1: light absorption band (1st light absorption band) 1st area, 36-2 : Light absorption band (1st light absorption band) 2nd area | region, 36A: Ink dot for light absorption bands (1st light absorption band), 36B: Ink layer for light absorption bands (1st light absorption band), 36 ': Light absorption band (1st light) Absorption band) counterpart, 136, 336: second light absorption band, 136-1: second light absorption band first region, 136-2: second light absorption band second region, 136-3: second light absorption band third region, 136A: ink dot for second light absorption band, 136B: ink layer for second light absorption band, 136 ': second light absorption band counterpart, 137: approximately flat surface region, 138: transition region, 139: prism row forming surface region, 37: convex part of uneven part, 38: light diffusing fine particle, 39: protrusion part, 4: light deflection Element, 41: light receiving surface, 42: light emitting surface, 5: light reflecting element, 6: light diffusing element, 61: incident surface, 62: exit surface, 64: dot pattern portion, 64 ': dot shape light absorbing ceramic material, 70 : Recessed part, 102: LED, 104: light guide, 141: light incident cross section, 143: light exit surface, 431: high light diffusion region, 143a: prism row, 144: lens row forming surface, 144a: lens row, 144b : Flat part, 106: light deflection element, 161: light incident surface, 161a: lens row, 162: light exit surface, 108: light reflecting element, 110: light diffusing reflective sheet, 150: inclined lens row, 152: dot pattern

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings.

1 is a schematic perspective view showing one embodiment of a surface light source device according to the present invention. As shown in FIG. 1, the surface light source device of this embodiment is a light guide which makes at least one side cross section the light incident end surface 31, and has one surface orthogonal to this as the light output surface 33. As shown in FIG. A sieve 3, a linear primary light source 1 disposed to face the light incident end face 31 of the light guide 3 and covered by the light source reflector 2, and a light exit surface of the light guide 3. The light deflecting element 4 disposed above, the light diffusing element 6 disposed opposite to this on the light exiting surface 42 of the light deflecting element 4, and the light exiting surface 33 of the light guide 3. It consists of the light reflection element 5 arrange | positioned facing the back surface 34 on the opposite side.

The light guide 3 is arrange | positioned in parallel with XY surface, and has a rectangular plate shape as a whole. The light guide 3 has four side cross sections, and among them, at least one side cross section of a pair of side cross sections parallel to the YZ plane is used as the light incident cross section 31. The light incident end surface 31 is disposed opposite to the primary light source 1, and the light generated from the primary light source 1 enters the light guide 3 from the light incident end surface 31. In the present invention, for example, the light source may be disposed opposite to other side cross sections such as the side cross section 32 on the side opposite to the light incident end face 31.

Two main surfaces substantially orthogonal to the light incident end surface 31 of the light guide 3 are located substantially parallel to the XY plane, respectively, and one surface (the upper surface in the drawing) is the light exit surface 33. At least one of the light exit surface 33 or the rear surface 34 of the light exit surface 33 or a plurality of lens rows such as a directional light output mechanism comprising a rough surface, a prism row, a lenticular lens row, a V-shaped groove, etc. By providing a directional light output mechanism or the like composed of a lens surface formed in parallel with the incident end surface 31 in parallel, the light exit surface 33 while guiding the light incident from the light incident end surface 31 into the light guide 3. Is emitted from the light incident end surface 31 and the light exit surface 33 in the plane (XZ plane) orthogonal to the light incident surface 31). The angle which the direction (peak light) of the peak of the emission light intensity distribution in this XZ in-plane distribution makes with the light emission surface 33 is made into (alpha). The angle α is, for example, 10 to 40 degrees, and the full width at half maximum of the emitted light intensity distribution is, for example, 10 to 40 degrees.

As for the rough surface formed on the surface of the light guide 3 and the lens row, the average inclination angle (theta) a by ISO 4287 / 1-1984 shall be in the range of 0.5-15 degree of the brightness | luminance in the light emission surface 33 It is preferable at the point which aims at uniformity. The average inclination angle θa is more preferably in the range of 1 to 12 degrees, and more preferably in the range of 1.5 to 11 degrees. The average inclination angle θa is preferably set by the ratio L / t of the thickness t of the light guide 3 and the length L of the direction in which the incident light propagates. That is, when using L / t of about 20-200 as the light guide 3, it is preferable to make average inclination-angle (theta) a into 0.5-7.5 degree, More preferably, it is the range of 1-5 degree, Preferably it is the range of 1.5-4 degree. In addition, when using L / t about 20 or less as the light guide 3, it is preferable to set average inclination-angle (theta) a to 7-12 degrees, More preferably, it is the range of 8-11 degrees.

The average inclination angle θa of the rough surface formed on the light guide 3 is obtained according to ISO 4287 / 1-1984 by measuring the rough surface shape using a stylus type surface roughness meter, x coordinate in the measurement direction, From the function f (x) the following equation (1) and equation (2)

Can be obtained using Here, L is a measurement length and (DELTA) a is the tangent of an average inclination-angle (theta) a.

Moreover, as the light guide 3, it is preferable that the emission rate exists in 0.5 to 5% of range, More preferably, it is 1 to 3% of range. This is because when the light emission rate is less than 0.5%, the amount of light emitted from the light guide 3 becomes small, and thus, sufficient luminance is not obtained, and when the light emission rate is greater than 5%, a large amount is provided in the vicinity of the primary light source 1. This is because the light is emitted, the attenuation of the emitted light in the X direction in the light exit surface 33 becomes remarkable, and the uniformity of the luminance at the light exit surface 33 tends to decrease. Thus, by setting the light emission rate of the light guide 3 to 0.5 to 5%, the angle of the peak light in the outgoing light intensity distribution (in the XZ plane) of the light exiting from the light exit surface is 50 to the normal line of the light exit surface. In the range of 80 degrees, the light having a high directional emission characteristic in such a manner that the half width of the emitted light intensity distribution (in the XZ plane) in the XZ plane perpendicular to both the light incident end face and the light exit face is in the range of 10 to 40 degrees. The surface light source device which can emit from the light guide 3, can efficiently deflect the emission direction to the optical deflecting element 4, and can have high brightness.

In the present invention, the light emission rate from the light guide 3 is defined as follows. Light intensity I ₀ of the outgoing light at the edge of the light exit face 31 on the light incident end face 31 side and exit light intensity I at the position L from the edge of the light incident end face 31 side ), The thickness (Z direction dimension) of the light guide 3 is t, the following formula (3)

Satisfies the relationship Here, the constant α is the light emission rate, and per unit length (length corresponding to the light guide thickness t) in the X direction orthogonal to the light incident end surface 31 on the light exit surface 33. It is the ratio (percentage:%) which light exits from the light guide 3. This emission rate α can be obtained from the gradient by taking the number of light intensities of the emitted light from the light exit surface 23 on the vertical axis, taking the L / t on the horizontal axis, and showing these relationships.

In addition, in order to control the directivity in the surface (YZ plane) parallel to the primary light source 1 of the outgoing light from the light guide 3, the other main surface to which the directional light output mechanism was not provided was made. It is preferable to form a lens surface in which a plurality of lens rows are arranged extending in a direction substantially perpendicular to the direction (X direction). In the embodiment shown in FIG. 1, an array of a plurality of lens rows is formed on a light exit surface 33 and extends in a substantially vertical direction (X direction) with respect to the light incident end surface 31 on the back surface 34. The lens surface which consists of these is formed. In the present invention, a lens surface may be formed on the light exit surface 33 and the rear surface 34 may be roughened, as opposed to the embodiment shown in FIG. 1.

As shown in FIG. 1, when a lens row is formed on the back surface 34 or the light exit surface 33 of the light guide 3, the lens row includes a prism row extending in the X direction, a lenticular lens row, Although V-shaped groove | channel etc. are mentioned, It is preferable to make the shape of a YZ cross section into a substantially triangular prism row.

In the present invention, when the prism rows are formed on the rear surface 34 of the light guide 3 as lens rows, the vertex angle is preferably in the range of 85 to 110 degrees. This is because by setting the vertex angle in this range, the light emitted from the light guide 3 can be properly focused, and the luminance as the surface light source device can be improved, and more preferably in the range of 90 to 100 degrees.

In the light guide of the present invention, a prism is formed in order to accurately produce a desired prism column shape, to obtain stable optical performance, and to suppress wear and deformation of the prism portion at the time of assembly work or use as a light source device. You may form a flat part or a curved part in the row | route part.

Further, in the present invention, instead of or in combination with forming the light emitting mechanism on the light emitting surface 33 or the back surface 34 as described above, the directional light output by mixing and dispersing the light diffusing fine particles in the light guide body. You may give a mechanism.

The light incident end surface 31 is preferably roughened in order to adjust the magnification of light in the XY plane and / or in the XZ plane. As a method of forming a rough surface, the method of cutting with a fly tool etc., the method of grinding by a grindstone, a side pepper, a buff, etc., the method by blast processing, an electric discharge processing, electrolytic polishing, chemical polishing, etc. are mentioned. Examples of the blast particles used for blasting include spherical ones such as glass beads and polygonal ones such as alumina beads, but the one using the polygonal one can form a rough surface having a greater effect of expanding light. desirable. Anisotropic roughening surface can be formed by adjusting the cutting direction of cutting and polishing. In order to adjust the magnification of light in the XY plane, the machining direction in the Z direction can be adopted to form a concave-convex shape in the Z direction, and in order to control the expansion of light in the XZ plane, the machining direction in the Y direction is Since roughness in the Y direction can be formed, this roughening can be performed directly on the light incident end face of the light guide, but the portion corresponding to the light incident end face of the mold is processed and transferred to the mold. Can be.

The degree of roughening of the light incident end surface 31 is 1-5 degrees in average tilt angle (theta) a in the light guide thickness direction, 0.05-0.5 micrometer of center line average roughness (Ra), and 0.5 ten-point average roughness (Rz). It is preferable that it is-3 micrometers. This is because, by setting the degree of roughening of the light incident end surface 31 to this range, it is possible to suppress the occurrence of bright or dark bands and to make it difficult to blur the bright and dark lines. The average inclination angle θa is more preferably in the range of 2 to 4.5 degrees, particularly preferably in the range of 2.5 to 3 degrees. The centerline average roughness Ra is more preferably in the range of 0.07 to 0.3 µm, particularly preferably 0.1 to 0.25 µm. Ten-point average roughness Rz becomes like this. More preferably, it is 0.7-2.5 micrometers, Especially preferably, it is the range of 1-2 micrometers. Further, the degree of roughening of the light incident end surface 31 is in the longitudinal direction, for the same reason as described above, the average inclination angle θa is 1 to 3 degrees, the center line average roughness Ra is 0.02 to 0.1 µm, and the ten point average roughness. It is preferable that (Rz) is 0.3-2 micrometers. Average inclination angle (theta) a becomes like this. More preferably, it is 1.3-2.7 degree | times, Especially preferably, it is the range of 1.5-2.5 degree | times. Centerline average roughness Ra becomes like this. More preferably, it is 0.03-0.08 micrometer, Especially preferably, it is the range of 0.05-0.07 micrometer. Ten-point average roughness Rz becomes like this. More preferably, it is 0.4-1.7 micrometers, Especially preferably, it is the range of 0.5-1.5 micrometers.

On the light exit surface 33 of the light guide, the first absorption band 36 and the second light absorption band 136 extending along the light incident end face 33 are arranged in this order from the side closer to the light incident end face 31. Are arranged. These 1st and 2nd light absorption bands 36 and 136 can be formed by apply | coating a black ceramic material, for example. Although the formation of the light absorption bands 36 and 136 is not specifically limited, For example, it is possible to carry out by application | coating of ink, and it is especially preferable by inkjet printing, screen printing, ballistic printing, or thermal transfer printing. Moreover, as a material of the light absorption bands 36 and 136, it is preferable to use a quick-drying material from a viewpoint of productivity, It is preferable that a drying time is 60 second or less, More preferably, it is 40 second or less, More preferably, 20 It is preferable that it is less than a second. Examples of such light absorption band materials include organic solvents such as ethyl methyl ketone, organic solvent-based paints using (meth) acryletomonoma, and the like, evaporative drying ink, thermosetting ink, ultraviolet ray-curable paint, ultraviolet curable ink, and the like. Can be mentioned.

The first absorption band 36 absorbs a part of the light introduced into the light guide 3 from the light incident end face 31 and prevents the generation of the bright line in the vicinity of the light incident end face 31. The light transmittance (JIS-K7105B) is, for example, 0 to 90%, preferably 0 to 60%, more preferably 2 to 45%, particularly preferably 4 to 30%. Moreover, it is preferable that the reflectance (JIS-K7105B) of the 1st light absorption band 36 is 0 to 20%, More preferably, it is 0 to 15%. In addition, although it is thought that this bright line generation | occurrence | production contributes the light which enters into the light guide body from the light emission surface 33 by the reflection by the light source reflector 2, without passing through a light incident cross section, the 1st light absorption band 36 has such a light intensity. Absorption of some prevents the generation of bright lines.

The second light absorption band 136 is a portion of the light introduced into the light guide 3 from the back surface 34 by the light introduced from the light incident end face 31 into the light guide 3 or the reflection by the light source reflector 2. By absorbing the light, the bright light is prevented by the first light absorption band 36, and the luminance in the region in the vicinity of the region where the luminance is lowered is reduced. As a result, bright lines are prevented from being generated by the first absorption band 36, and the occurrence of locally abrupt changes in luminance in the region where the luminance is lowered and in the vicinity thereof is prevented. In order to satisfactorily realize such a brightness adjusting action of the second light absorption band 136, the visible light transmittance of the second light absorption band 136 is preferably higher than the visible light transmittance of the first light absorption band 36. The reason for this is as follows. The cause of the bright line involved in the second light absorption band 136 is generally the light introduced into the light guide 3 from the light incident end face 31 or the reflection path from the back surface 34 by the light source reflector 2. A part of the light received into the light guide 3 totally reflects to both the light output surface 33 and the back surface 34, the light guide light in the effective light emitting area of the surface light source device and in the display area of the liquid crystal display device. It relates to the exit surface 33. These bright lines are generally weak light bands having a larger magnification than the bright lines in which the first light absorption band 36 is involved, and the first light absorption band 36 is used to improve the sudden change in luminance and to make a smooth output light distribution. It is suitable to use a light absorption band having a transmittance higher than that of (). In addition, since the second light absorption band 136 is located at a position away from the light guide end face 31 of the light guide than the first light absorption band 36, the second light absorption band 136 significantly loses the mode of light guiding the inside of the light guide body and thus is within the effective light emission region. Further, there is a high risk of causing uneven luminance of dark lines or dark bands in the display area. Also from such a viewpoint, it is preferable to use the high visible light transmittance (low visible light transmittance) as the 2nd light absorption band 136. FIG. The visible light transmittance (JIS-K7105B) of the second light absorption band 136 is, for example, 40 to 95%, preferably 60 to 90%, and more preferably 70 to 90%. In the state where the light source reflector is arranged, the reflectance (JIS-K7105B) of the second light absorption band 36 is preferably 40 to 95%, preferably 60 to 90%, and more preferably 70 to 90%. 90%.

The thickness of the light guide 3 is, for example, about 1.5 to 4 mm, preferably 2 to 3 mm in the vicinity of the light incident end face 31.

2 is a schematic plan view of the light guide 3 together with the primary light source 1. As shown in FIG. 2, the first light absorption band 36 does not block light incident from the light incident end face 31, but reduces the luminance due to a decrease in the amount of incident light or blocks light to be guided. In order to suppress the generation of dark lines, it is necessary to be formed only on the light exit surface 33 of the light guide 3 and not to be formed on the light incident end surface 31. Further, the first light absorption band 36 has a width (X direction dimension) of W1, and the side edge on the side closer to the light incident end face 31 and the light incident end face 31 of the two side edges defining the width thereof. The distance to is D1. Width W1 is 50-800 micrometers, Preferably it is 100-500 micrometers, Especially preferably, it is 150-400 micrometers. If the width W1 is less than 50 µm, the effect of preventing the occurrence of necessary bright lines tends to decrease. If the width W1 exceeds 800 µm, dark lines tend to occur or the overall luminance decreases. The width W1 is preferably 0.4 times or less, more preferably 0.3 times or less, and particularly preferably 0.2 times or less of the thickness at the light incident end surface position of the light guide 3. In addition, when the distance D1 is 300 µm or less, the above-mentioned effect of preventing the generation of bright lines is obtained, preferably 200 µm or less, and particularly preferably 100 µm or less.

On the other hand, the second light absorption band 136 has a width (X direction dimension) of W2, and the side edge near the light incident end face 31 and the light incident end face 31 of the two side edges defining the width thereof. The distance to is D2. Width W2 becomes like this. Preferably it is 50-800 micrometers, More preferably, it is 100-700 micrometers, Especially preferably, it is 150-600 micrometers. If the width W2 is less than 50 µm, the required luminance adjustment effect tends to be lowered. If the width W2 exceeds 800 µm, the overall luminance decreases and the reflection of the dark band tends to occur. In addition, when the distance D2 is in the range of 500 to 3000 µm, the above-described brightness adjustment effect is obtained, preferably in the range of 700 to 2000 µm, and particularly preferably in the range of 900 to 1500 µm.

On the basis of forming the first absorption band 36 on the light exit surface 33 of the light guide 3, a recess is formed in at least a part of the first light absorption band formation portion of the light exit surface 33, and the recess is formed. You may apply | coat a paint etc. to a part and form a 1st light absorption band. That is, as shown in FIG. 8 and FIG. 9, the concave portion 70 having, for example, a cross-sectional triangle or a lenticular shape is, for example, 150 μm or less in depth, preferably 100 on the light exit surface 33. The first absorption zone 36 is formed to have a depth of 50 m or less, more preferably 50 m or less, and to include the inside of the recess. If the depth of the concave portion 70 is too large, the waveguide mode in the light guide is insufficient, and dark lines easily appear. Similarly with regard to the second light absorption band 136, a recess is formed in at least a part of the second light absorption band forming portion of the light exit surface 33, and a coating or the like is applied to the recess to form the second light absorption band. good.

As the light guide 3, it is not limited to the shape as shown in FIG. 1, The thing of various shapes, such as a wedge shape with a thick light incident cross section, can be used.

3 and 4, an example of the manufacturing method of the light guide as described above will be described. Fig. 3 is a schematic plan view showing the light guide material 3 'obtained by molding by a resin molding process and applying the porcelain serving as the first and second light absorption bands. When the light guide material 3 'shows a part corresponding to each part of the light guide 3 finally obtained as a corresponding part, the light incident end face corresponding part 31' and the light exit surface corresponding part 33 ' ), A first light absorption band counterpart 36 'and a second light absorption band counterpart 136'. The mat surface as a rough surface which comprises a required light output mechanism is formed in the light exit surface correspondence part 33 ', and the required prism row is formed in the back surface correspondence part on the opposite side. The first light absorption band corresponding portion 36 'is formed in a region proximate the light incident end surface corresponding portion 31' of the light exit surface corresponding portion 33 ', and the first light absorption band corresponding portion 36' is formed. The second light absorption band corresponding portion 136 'is formed in an area away from the second light absorption band.

As shown in FIG. 4, the light incidence end face 31 is formed as a cutting surface by performing a cutting process with respect to the light-incidence end face correspondence part 31 ', and cutting an unnecessary part. Thus, the light generated from the primary light source 1 can be configured to easily enter the light incident end face 31 up to the boundary with the light exit surface 33. 3 and 4, the first light absorption band corresponding portion 31 ′ is formed in the unnecessary portion cut out by cutting, and the cutting of the first light absorption band corresponding portion 31 ′ in cutting is performed. Simultaneously cutting off the side edge close to the light incident end face correspondence portion 31 'makes the distance D1 easy to 0 占 퐉, and the light incident end face 31 with the light exit face 33. The light generated from the primary light source 1 up to the boundary can be configured to be incident. The second light absorption band counterpart 136 'can be used as the second light absorption band 136 as it is.

The light deflecting element 4 is disposed on the light exit surface 33 of the light guide 3. The two main surfaces 41 and 42 of the light deflecting element 4 are arranged in parallel with each other as a whole, and are respectively located in parallel with the XY plane as a whole. One of the main surfaces 41 and 42 (the main surface located on the light exit surface 33 of the light guide 3) is the light incident surface 41, and the other is the light exit surface 42. The light exit surface 42 is a flat surface parallel to the light exit surface 33 of the light guide 3. The light incident surface 41 is a prism row forming surface in which a plurality of prism rows extending in a plurality of Y directions are arranged in parallel with each other. The prism row forming surface may have a relatively narrow flat portion (e.g., a flat portion having a width equal to or smaller than the X-direction dimension of the prism row) between adjacent prism rows, but from the point of increasing light utilization efficiency It is preferable to arrange the prism rows continuously in the X direction without providing a portion.

5 shows an embodiment of light deflection by the light deflection element 4. This figure shows the advancing direction of the peak light (light corresponding to the peak of the emitted light distribution) from the light guide 3 in the XZ plane. The peak light inclined at an angle α from the light exit surface 33 of the light guide 3 is incident on the first side of the prism row and totally reflected by the second side in the direction of the normal to the exit surface 42. Exit. In addition, within the YZ plane, a sufficient improvement in the luminance in the direction of the normal line of the light exit surface 42 can be achieved in a wide range of regions by the action of the prism heat of the light guide body 34 as described above.

The shape of the prism face of the prism row of the optical deflection element 4 is not limited to a single plane, but can be, for example, a cross-sectional convex polygonal shape or a convex curved shape, whereby high luminance and narrow field of view can be achieved. Can be.

In the optical deflecting element of the present invention, the prism heat is fixed for the purpose of accurately producing a desired prism shape, obtaining stable optical performance, and suppressing wear and deformation of the prism portion at the time of assembly work or use as a light source device. The flat portion or the curved portion may be formed in the. In this case, it is preferable that the width of the flat portion or the curved portion formed in the prism thermal portion is 3 占 퐉 or less from the viewpoint of suppressing the occurrence of the uneven pattern of luminance due to the decrease in luminance or sticking phenomenon as the light source device. Preferably it is 2 micrometers or less, More preferably, it is 1 micrometer or less.

In the present invention, the light diffusing element 6 can be arranged adjacent to the light exit surface of the light deflecting element 4 in order to appropriately control the viewing range according to the purpose without causing a decrease in luminance. In addition, in this invention, by arrange | positioning the light-diffusion element 6 in this way, the quality improvement can also be aimed at by suppressing the lumps, luminance unevenness, etc. which become a cause of quality deterioration.

In order to prevent sticking with the light deflecting element 4, it is preferable to give an uneven structure to the incident surface 61 facing the light deflecting element 4 of the light diffusing element 6. Similarly, also in the emission surface 62 of the light diffusion element 6, in consideration of the prevention of sticking between the liquid crystal display elements disposed thereon, the surface of the light diffusion element 6 is uneven It is preferable to give a structure. When providing this uneven structure only for the purpose of sticking prevention, it is preferable to set it as the structure which average angle of inclination becomes 0.7 degrees or less, More preferably, it is 1 degree or more, More preferably, it is 1.5 degree or more.

The light diffusivity of the light diffusing element 6 incorporates a light diffusing agent such as silicone beads, polystyrene, polymethyl methacrylate, fluorinated methacrylate or the like in the light diffusing element 6, or the like. And imparting an uneven structure to at least one surface of the light diffusion element 6. The uneven structure formed on the surface differs in the case where it is formed in one surface of the light-diffusion element 6, and when formed in both surfaces. In the case where the uneven structure is formed on one surface of the light diffusion element 6, the average inclination angle is preferably in the range of 0.8 to 12 degrees, more preferably 3.5 to 7 degrees, and more preferably 4 to 6.5 It is also. In the case where the uneven structure is formed on both surfaces of the light diffusing element 6, the average inclination angle of the uneven structure formed on one surface is preferably in the range of 0.8 to 6 degrees, more preferably 2 to 4 degrees. More preferably, it is 2.5-4 degrees. In this case, in order to suppress the fall of the total light transmittance of the light diffusing element 6, it is preferable to make the average inclination angle of the incident surface side of the light diffusing element 6 higher than the average inclination angle of the emission surface side.

In addition, the haze value of the light diffusing element 6 is preferably in the range of 8 to 82%, preferably from the viewpoint of improving the luminance characteristic and improving the visibility, and more preferably in the range of 30 to 70%, More preferably, it is 40 to 65% of range.

FIG. 6 is a schematic plan view of the light diffusing element 6 together with the primary light source 1. As shown in FIG. 1 and FIG. 6, the dot pattern portion 64 is formed in the light diffusion element 6. The dot pattern portion is formed by disperse-distributing a dot-shaped light absorbing ceramic material having a diameter of 30 μm to 70 μm on the exit surface 62. The dot pattern part has a distance d2 from the position of the distance d1 from the light incident end face of the light guide. It exists in the area | region of width d2-d1 including up to a position. It is preferable that the distance d1 is 2 mm or less, and the distance d2 is 4 mm or more. This makes it possible to appropriately suppress the overall brightness in the vicinity of the primary light source position and obtain a luminance distribution with less discomfort along the light emitting surface. In order to obtain such an effect efficiently, the dot pattern portion 64 preferably has a visible light transmittance of 60% to 95%. In addition, in order to obtain a luminance distribution with less discomfort, the density of the dispersion arrangement of the dot-shaped light absorbing ceramic material is moved away from the primary light source in at least a part of the width region close to the position of the distance d2 from the light incident end surface. It is preferable to make it small.

The primary light source 1 is a linear light source extending in the Y direction, and as the primary light source, for example, a fluorescent lamp or a cold cathode tube can be used. In this case, as shown in FIG. 1, the primary light source 1 can be provided not only in the case where it is opposite to one side end surface of the light guide 3, but also in the side end surface of the opposite side as needed. In the present invention, the primary light source 1 is not limited to a linear light source, and a point light source such as an LED light source, a halogen lamp, a metahalo lamp, or the like can also be used. In particular, when used in a display device having a relatively small screen size such as a cellular phone or a portable information terminal, it is preferable to use a small point light source such as an LED. Thus, when using a point light source as the primary light source 1, arrangement | positioning of the primary light source 1 can be arrange | positioned at the corner part of the light guide 3, etc. As shown in FIG. In this case, light incident on the light guide 3 emits light from the light guide 3 so as to propagate the light guide center radially about the primary light source 1 in the same plane as the light exit surface. It is preferable from the viewpoint of the uniformity of luminance to form a light output mechanism in which a plurality of lens rows are formed in parallel in a substantially half-moon shape with the point light source surrounded on the surface. In addition, in order to emit light emitted from the light exit surface of the light guide 3 in a radial manner centering on the primary light source 1, the exit light emitted in this radial direction is efficient regardless of the exit direction. In order to deflect in the desired direction, it is preferable to arrange the prism rows formed in the light deflection element 4 in parallel in a substantially half-moon shape so as to surround the primary light source 1 from the viewpoint of uniformity of luminance.

The light source reflector 2 will guide the light of the primary light source 1 to the light guide 3 with little loss. As a material of the light source reflector 2 with a strong tendency of regular reflection, the plastic film which has a metal vapor deposition reflective layer on the surface can be used, for example. As shown, the light source reflector 2 avoids the light diffusing element 6 and the light deflecting element 4 from the outer edge of the end edge portion of the light reflecting element 5 through the outer surface of the primary light source 1. It is wound around the light exit surface edge part of (3). On the other hand, the light source reflector 2 avoids only the light diffusing element 6 and passes from the outer edge of the light reflecting element 5 to the edge of the light exit surface of the light deflecting element 4 via the outer surface of the primary light source 1. It is also possible to wind up, or it is also possible to wind around the edge of the exit surface of the light-diffusion element 6 from the outer edge of the light reflection element 5 via the outer surface of the primary light source 1. Or it may be wound up from the light guide back surface 34, avoiding the light reflection element 5. As shown in FIG.

It is also possible to attach a reflecting member such as the light source reflector 2 to the side end surface other than the side end surface 31 of the light guide 3.

As the light reflection element 5, the plastic sheet which has a metal vapor deposition reflection layer on the surface can be used, for example. In the present invention, instead of the reflective sheet, it is also possible to use a light reflecting layer or the like formed on the back surface 34 of the light guide 3 by metal deposition or the like as the light reflecting element 5.

The light guide 3, the light deflecting element 4 and the light diffusing element 6 of the present invention can be made of a synthetic resin having a high light transmittance. As such a synthetic resin, methacryl resin, acrylic resin, polycarbonate resin, polyester resin, vinyl chloride resin, and cyclic polyolefin resin can be illustrated. In particular, methacryl resin is excellent in the height of light transmittance, heat resistance, a mechanical characteristic, and moldability. As such methacryl resin, it is preferable that methyl methacrylate is 80 weight% or more as resin which has methyl methacrylate as a main component. In forming the surface structure of the light guide 3, the light deflecting element 4, and the light diffusing element 6, such as a rough surface or a hairline, and a surface structure such as a prism row or a lenticular lens row, a transparent synthetic resin plate is desired. It may be formed by hot pressing using a mold member having a surface structure, or may be shaped simultaneously with molding by screen printing, extrusion molding or injection molding. Moreover, a structural surface can also be formed using heat or photocurable resin. Moreover, the roughening structure which consists of active-energy-ray-curable resin on the surface of transparent base materials, such as a transparent film or sheet which consists of polyester resin, acrylic resin, polycarbonate resin, vinyl chloride resin, polymethacryl imide resin, etc. In addition, a lens array structure may be formed, and such a sheet may be integrally bonded on a separate transparent substrate by a method such as adhesion or fusion. As active energy ray hardening type resin, a polyfunctional (meth) acryl compound, a vinyl compound, (meth) acrylic acid ester, an aryl compound, the metal salt of (meth) acrylic acid, etc. can be used.

The light emitting surface of the surface light source device comprising the primary light source 1, the light source reflector 2, the light guide 3, the light deflecting element 4, the light diffusing element 6 and the light reflecting element 5 as described above [ The liquid crystal display device having the surface light source device of the present invention as a backlight is configured by disposing a liquid crystal display element LC on the exit surface 62 of the light diffusing element 6 as shown in FIG. 7. do. In FIG. 7, the dot-shaped light absorptive ceramic material of the dispersion arrangement which comprises the dot pattern part of the light-diffusion element 6 is shown with the code | symbol 64 '. The liquid crystal display device passes the liquid crystal display element LC from above in FIG. 7, and is observed by an observer. The display area of the liquid crystal display device is determined by the display area of the liquid crystal display element LC or the opening area of the frame holding the liquid crystal display element. The effective light emitting area of the surface light source device is larger than the display area of the liquid crystal display device and exists to cover all of the display areas. The first light absorption band 36 is disposed outside the display area and outside the effective light emission area. The second light absorption band 136 is disposed so as to be positioned outside the display area, but may extend over the effective light emission area.

In FIG. 7, the case where the said distance D1 is 0 micrometer in the light guide 3 is shown. As shown, the first light absorption band 36 extends to the boundary with the light incident end face 31, but not to the light incident end face 31. That is, the light incident end surface 31 is comprised so that the light which arises from the primary light source 1 may enter into the boundary with the light emission surface 33.

Moreover, the light source reflector 2 is arrange | positioned so that the edge part may cover the 1st and 2nd light absorption bands 36 and 136. As shown in FIG. However, the light source reflector 2 does not have to cover the second light absorption band 136. An area of about 2 to 4 mm in width of the outer circumference of the light emitting surface of the surface light source device is covered by the frame, and no light is emitted to the outside from this area (frame frame area). The end edge portion of the light source reflector 2 is located within the frame frame area, and thus the first and second light absorption bands 36 and 136 are located within the frame shape area, that is, outside the effective light emitting area of the surface light source device. However, the second light absorption band 136 may be located outside the frame-shaped region, that is, within the effective light emitting region of the surface light source device.

Most of the light L1 reaching the first light absorption band 36 among the light introduced from the light incident end face 31 into the light guide 3 is absorbed by the first light absorption band. The rest of the light is reflected by the light exit surface 33, and becomes light L2 traveling in the light guide. The light L2 is emitted from the back surface 34, reflected by the reflecting element 5, reincident into the light guide body, and exits from the light exit surface 33. In the present invention, the light L2 can be sufficiently weaker than the light L1 by the light absorption in the first light absorption band 36, and therefore, hardly causes the bright line. For example, if the first absorption band 36 does not exist, the intensity of this light L2 becomes quite strong. This light L2, i.e., the reflected light at the portion where the first absorption band 36 is attached in the present invention, is the biggest cause of the bright line generation, and when the first light absorption band 36 does not exist, the outstanding bright line occurs. do.

In particular, when the light source reflector 2 has a strong specular tendency, when the first light absorption band 36 does not exist, a part of the light in the light guide 3 is directed to the light exit surface 33. Since the light is reflected and reflected by the reflector 2 which is a light source, it penetrates the light exit surface 33 again and is introduced into the light guide 3, and thus, a very noticeable bright line is generated based on this. In order to prevent the generation of such very noticeable bright lines, it is preferable to use a sufficiently low visible light transmittance as the first light absorption band 36. However, in the case where the occurrence of the noticeable bright line by the first light absorption band 36 is prevented in this way, the luminance of the region where the bright line is reduced decreases excessively compared with the luminance of the region in the vicinity thereof, and the contrast of the luminance in these regions is reduced. (I.e., a sudden sharp change in luminance occurs locally), the hidden line removal region may be viewed as a dark line, or may be viewed as a dark line while the area near the bright line reduction area is weak. In other words, even if the noticeable bright line is removed, a sudden sharp change in brightness occurs locally, which may lower the quality of the display image when used as a backlight of the display device.

By the way, in this invention, by arrange | positioning the 2nd light absorption band 136, the brightness | luminance of the area | region in the vicinity of a bright line reduction area | region is adjusted brightness so that the difference with the brightness of a bright line reduction area | region may become small, and the locally abrupt brightness | luminance in these areas is reduced. The change is not caused to occur, that is, the luminance contrast in these areas is not increased. Therefore, the bright line reduction area is not visually recognized as the dark line or the area in the vicinity thereof is visually recognized as the bright line.

That is, in the light introduced from the light incident end face 31 into the light guide 3, part of the light L3 reaching the second light absorption band 136 is absorbed by the second light absorption band. The rest becomes light L4 which is reflected by the light exit surface 33 and propagates in the light guide body. This light L4 is emitted from the back surface 34, reflected by the reflecting element 5, reincident into the light guide body, and exits from the light exit surface 33. In the present invention, the light L4 can be made weaker than the light L3 by the light absorption in the second light absorption band 136. Therefore, the intensity difference with the light L2 is reduced, and therefore, the light There is no significant difference in the luminance in the region where L2 is first emitted from the light exit surface and in the region where the light L4 near the first exits from the light exit surface (that is, the luminance contrast is not large).

In particular, the light L5 introduced into the light guide 3 from the edge portion that forms the boundary between the light guide back surface 34 and the light incident end face 31 and reaches the second light absorption band 136 is the second light. Part of it is absorbed by the light absorption band. The remainder is reflected by the light exit surface 33 to become light L6 traveling in the light guide. This light L6 is emitted from the back surface 34, reflected by the reflecting element 5, reincident into the light guide body, and exits from the light exit surface 33. In the present invention, the light L6 can be made weaker than the light L5 by the light absorption in the second light absorption band 136, and therefore, the intensity difference with the light L2 is reduced, so that the light There is no significant difference in the luminance in the region where L2 first emits from the light exit surface and in the region where the light L6 near the first exits from the light exit surface (that is, the brightness contrast is not large).

In addition, some of the light generated from the primary light source 1 is reflected from the light source reflector 22 and reaches the first and second light absorption bands 36 and 136 without reaching the light incident end face 31. In the placenta is absorbed. For example, if the light absorption bands 36 and 136 do not exist, light is absorbed into the light guide from the light exit end face 33 at the portion where the light absorption bands 36 and 136 are attached in the present invention. This light is also a cause of the above-mentioned bright line, and also in this point, when the light absorption bands 36 and 136 do not exist, the bright line is generated.

In the present invention, since the light having a narrowly collimated luminance distribution (in the XZ plane) can be incident on the liquid crystal display element LC from the light source device, brightness and color uniformity are eliminated without the gray level inversion in the liquid crystal display element. While good image display can be obtained, light irradiation concentrated in a desired direction can be obtained, and the utilization efficiency of the amount of emitted light of the primary light source 1 for illumination in this direction can be improved.

In the description of the above embodiments, the first and second light absorption bands 36 and 136 have been described as having almost uniform light absorption characteristics in both the width directions, but in the present invention, the first and second light absorption bands have their light absorption. The characteristic may change in the width direction. As a preferable aspect of such light absorption characteristics, what is formed so that the side edge side which is farther from the side edge | side near the light incident cross section of the 1st light absorption band 36 may become high visible light transmittance. By doing so, it is possible to prevent a sudden change in the light absorbency at the boundary between the region of the first light absorption band 36 and the light guide light emitting surface 33 on which it is not formed, and further reduce the occurrence of sudden local brightness change. can do. Similarly with respect to the second light absorption band 136, the edges on both sides of the second light absorption band 136 are formed so that the visible light transmittance is increased. By doing so, a sudden change in the light absorbency at the boundary between the region of the second light absorption band 136 and the light guide light exit surface 33 in which it is not formed is prevented, and the occurrence of a sudden sudden brightness change is further reduced. can do.

For example, as shown in FIG. 10, the 2nd area | region 36-2 which makes the 1st light absorption band 36 far from the 1st area | region 36-1 which is close to the light incident cross section with respect to the width direction (X direction). ), And the thickness of the first region 36-1 is approximately twice the thickness of the second region 36-2, so that the visible light transmittance T2 of the second region 36-2 is obtained. Can be made higher than the visible light transmittance T1 of the first region 36-1. The first light absorption band 36 in which the visible light transmittance is changed in two stages is first applied with a uniform thickness to both the first region 36-1 and the second region 36-2, After that, it is possible to obtain additional porcelain coating only in the first region 36-1. Similarly, the first light absorption band in which the visible light transmittance is changed in three or more steps can be formed.

Similarly with regard to the second light absorption band 136, the first region 136-1, the second region 136-2, and the third region 136 in the order close to the light incident cross section in the width direction (X direction). -3), and the thickness of the second region 136-2 is about three times the thickness of the first and third regions 136-1 and 136-3, whereby the first and third regions Visible light transmittance T2 of (136-1, 136-3) can be made higher than visible light transmittance T3 of the 2nd area | region 136-2. The second light absorption band 136 in which the visible light transmittance is changed in two stages is first applied with a uniform thickness to all of the first to third regions 136-1 to 136-3. After that, it is possible to obtain additional porcelain coating only in the second region 136-2. Similarly, the second light absorption band in which the visible light transmittance is changed in three or more steps can be formed.

In addition, as shown in FIG. 11, the thickness of the first absorption band 36 is set to the side edge far from the side edge close to the light incident end face 31 with respect to the width direction (X direction) of the first light absorption band 36. By gradually making it small, the visible light transmittance of the 1st light absorption band 36 may be changed continuously to the width direction of the 1st light absorption band 36. FIG. Similarly, by gradually decreasing the thickness of the second light absorption band 136 from the center to both edges in the width direction (X direction) of the second light absorption band 136, the visible light transmittance of the second light absorption band 136 is reduced. The second light absorption band 36 may be continuously changed in the width direction. The first and second light absorption bands 36 and 136 of this type can be obtained by carrying out porcelain coating while moving the mask member from the side closer to the light incident end face 31 in the X direction. The continuous change in the visible light transmittance in the first and second light absorption bands 36 and 136 does not have to span the entire width direction but may be part of the width direction.

The change in the visible light transmittance in the first and second light absorption bands 36 and 136 may be a combination of the step change described with reference to FIG. 10 and the continuous change described with reference to FIG. 11.

As for the visible light transmittance of the 1st light absorption band 36, it is preferable that the lowest value exists in the range of 0%-60%, and the highest value exists in the range of 40%-90%. In addition, it is preferable that the lowest light transmittance of the second light absorption band 136 is in the range of 40% to 90%, and the highest value is in the range of 60% to 95%. When it exists in these ranges, generation | occurrence | production of a dark line can be prevented, maintaining the prevention effect of bright line generation, and generation | occurrence | production of a sudden sudden change of brightness | luminance can be further reduced.

12 and 13, another example of the method of manufacturing the light guide as described above will be described. 12 (a) and 13 (a) are partial plan views, and FIGS. 12 (b) and 13 (b) are XZ partial sectional views thereof.

First, as shown in FIG. 12, the width W1 ′ close to the light incidence end face 31 of the light exit face 33 of the light guide 3 and spaced apart from the light incidence end face distance D1 ′. The ink dots 36A that are independent or partially continuous with each other by the inkjet method are formed in the region of. As an apparatus used for implementing the inkjet method, the printer of the continuous (continuous injection) system and the DOD (dot on demand) system using a piezo nozzle is illustrated. By these apparatuses, ink is ejected from a plurality of nozzles, and the light guide 3 is scanned in a required direction parallel to the light exit surface 33 with respect to the nozzle, if necessary, so that a predetermined area of the light exit surface is provided. A plurality of independent ink dots 36A are formed as shown in FIG. All of these ink dots may be completely independent as shown, but some of them may partially overlap and continue.

Next, adjacent ones of the ink dots are bonded to form a continuous ink layer (hereinafter referred to as "leveling"). This leveling is carried out for the time required to obtain the required leveling amount. Thereby, as shown in FIG. 13, the ink layer which continued over the whole area | region of the width | variety W1 spaced apart from the light-incidence end surface 31 by distance D1 from the light incident end surface 31 is combined with each other. It becomes (36B). The area of the width W1 includes all of the areas of the width W1 ', and is slightly larger than the width W1' by leveling.

Next, the first light absorption band 36 is formed by curing the ink layer 36B.

As the ink, for example, an ultraviolet curable ink can be used. The ultraviolet curable ink can be suitably used since the required leveling amount can be easily achieved by controlling the timing of ultraviolet irradiation. In addition, in order to easily control the time for obtaining the required leveling amount, it is preferable to keep the temperature of the ink discharge nozzle, that is, the temperature of the ink constant. Moreover, also by heating the light guide 3, the viscosity of the ink dot 36A after ink ejection, such as ink droplets, can be reduced, thereby shortening time for obtaining the required leveling amount, and it is necessary for printing. It is possible to shorten the time required.

As described above, by controlling the bonding state of the ink dots in the ink layer 36B as desired by the leveling time, the surface state of the first light absorption band 36, that is, the degree of irregularities can be controlled. By providing appropriate irregularities on the surface of the first light absorption band 36, unnecessary light can be made less noticeable. That is, as described above, when a part of the light generated from the primary light source 1 is reflected from the light source reflector 22 and reaches the first absorption band 36 without reaching the light incident end face 31, here, Placenta is absorbed. At this time, the remaining light is reflected toward the light guide light exit surface 33, but the reflected light can be diffused and reflected by the unevenness of the surface of the first light absorption band 36, which can make it inconspicuous.

The higher the resolution of the printer, the ink dots can be formed closer to each other, and it is preferable to shorten the time required for leveling for joining the ink dots.

As mentioned above, what was stated about the 1st light absorption band 36 is suitable also in the 2nd light absorption band 136. As shown to FIG. That is, as shown in FIG. 12, inks deviating from the area of the width W1 ′ of the light emitting surface 33 of the light guide 3 similarly independently or partially continuous with each other by the inkjet method. A dot 136A is formed. All of these ink dots may be completely independent as shown, but some of them may partially overlap and continue. Next, the ink dot is leveled similarly. Thereby, as shown in FIG. 13, adjoining ones of the ink dots are combined, and it is set as the continuous ink layer 136B over the whole area | region deviating from the area | region of width W1. Next, the second light absorption band 136 is formed by curing the ink layer 136B. As described above, by controlling the bonding state of the ink dots in the ink layer 136B as desired by the leveling time, the surface state of the second light absorption band 136, that is, the degree of irregularities can be controlled. By forming an appropriate unevenness on the surface of the second light absorption band 136, it is possible to prevent unnecessary light from falling further. That is, as described above, when a part of the light generated from the primary light source 1 reaches the second light absorption band 136 without being reflected from the light source reflector 22 and reaching the light exit end face 31, the excitation In the placenta is absorbed. At this time, the remaining light is reflected toward the light guide light exit surface 33, but by reflecting the reflected light by the unevenness of the surface of the second light absorption band 136, it can be prevented from falling.

Further, by forming the first and second light absorption bands 36 and 136 as described above in parallel, the time for formation is shortened.

Another example of the manufacturing method of the light guide as described above will be described with reference to FIG. 14.

In this example, first, the light guide material 3 'as shown in Fig. 14A is prepared. Next, as shown in FIG.14 (b), the cutting process with respect to the light incident end surface correspondence part 31 'is performed, and the light incident end surface 31 is formed. By this cutting process, at the boundary between the light incidence end face 31 and the light exit face 33, the light exit face 33 protrudes toward the light exit face 33 (that is, it protrudes with respect to another area of the light exit face 33). ] The protrusion 39 is formed. The protrusion 39 extends along the boundary line between the light incident end face 31 and the light exit face 33, that is, along the light incident end face 31. The protrusion 39 can be formed by cutting as described above, but may be formed by molding at the time of injection molding.

Next, as shown in Fig. 14C, ink dots 36A and 136A are formed in required areas of the light exit surface 33. Next, as shown in FIG. This ink dot is formed as described with reference to FIG. Next, the ink dots are leveled, and ink layers 36B and 136B are formed in required areas of the light exit surface 33 as shown in Fig. 14D. The formation of these ink layers is described with reference to FIG. 13, but here, the side edges close to the light incident end face 31 of the ink layer 36B formed by leveling reach the protrusions 39, The position of the ink dot formation area is set. That is, the area | region in which the ink dot 36A shown in FIG.14 (c) is formed is only a little distance from the light incident end surface 31. FIG. As a result, the ink flowing during the leveling of the ink dots is prevented from moving to the light incident end face 31 by the protrusion 39.

Finally, the first and second light absorption bands 36 and 136 are formed by curing the ink layers 36B and 136B.

According to the above method, it is easy to form the first light absorption band 36 very close to the light incident end face 31 without following the light incident end face 31. According to this first absorption band 36, it is possible to control the reduction of the amount of light incident on the light guide 3 from the light incident end face 31. As shown in FIG.

In order to facilitate the action of the blocking at the proper position of the movement of the ink to the light incident end face 31 by the protrusion 39 and to facilitate the formation of the protrusion 39, the dimensions of the protrusion 39 are adjusted. It is preferable to set it as the following suitable range. That is, as shown in FIG. 18, the height of the protrusion 39 (height from another area of the light exit surface 33) is H, and the full width at half maximum of the height in the XZ cross-sectional shape of the protrusion 39. Is W, Preferably H is 1-50 micrometers, More preferably, it is 2-30 micrometers, More preferably, it is 5-20 micrometers, W is 1-50 micrometers, More preferably, it is 2-30 micrometers More preferably, it is 5-20 micrometers. If the protrusion height H is too small, the action of the ink movement blocking tends to be insufficient, and if the protrusion height H is too large, assembling of the surface light source device becomes difficult or distortion of the protrusion is likely to occur. This also tends to make it difficult to move the ink to the vicinity of the top of the projection. In addition, when the height half width W is too small, it is difficult to form protrusions, and the mechanical strength is lowered, and the action of ink movement prevention is less likely, and the height half width W is too large. There is a tendency that assembling becomes difficult and it becomes difficult to move the ink to the vicinity of the width of the protrusion.

In any of the methods described above, it is preferable to use an ultraviolet curable ink containing (meth) acrylate monomer and / or an organic solvent as the ultraviolet curable ink that is a porcelain for forming the light absorption band 36. This is because the bonding strength to the surface of the light guide 3 of the light absorption band 36 formed by curing the ink layer is advantageous. By the presence of the organic solvent in the ink width, it is possible to obtain an improvement in the anchor effect by melting and ruining the surface of the light guide 3. In particular, when (meth) acrylic resin is used as the light guide 3, (meth) acrylate monomer is present in the ink, so that crosslinking reaction occurs between the ink and the light guide during polymerization in the ink. It becomes easy, and the improvement of an anchor effect by this can be obtained.

It is preferable that the said (meth) acrylate monomer and the organic solvent have a number average molecular weight of 100 or more, Preferably it is 15 or less, More preferably, it is 200 or more so that ink density may not change significantly. (Meth) acrylate monomer is methyl methacrylate, for example, It is preferable that 0.5-10 weight% is contained in ink, for example. The organic solvent preferably has a boiling point of 60 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, so that the ink concentration does not change significantly. For example, methyl ethyl ketone, ethyl acetate, chloroform, or longitudinal acetate It is illustrated that it contains at least 1 of a sorb and a metal acrylic acid.

As such an ultraviolet curable ink, the thing of the composition shown below is mentioned, for example.

Ink 1:

Acrylic acid origoma: 30-50 wt%

Acryl isobonyl: 0-20 wt%

1, 6-hexanegiol acrylate: 1-20 wt%

Tetrahydrofurfuryl acrylate: 10-20 wt%

Benzophenone: 1-5 wt%

Carbon black: 1-5 wt%

Ink 2:

Acryl isobonyl: 0-20 wt%

1,6-hexaneziol acrylate: 1-20 wt%

Amiso acrylate / acrylate ester mixture: 30-50 wt%

Benzophenone: 1-5 wt%

Carbon black: 1-5 wt%

In the present invention, in the case of forming the light absorption band by the inkjet method or the like, as the ultraviolet curable ink, the ink viscosity is 1 to 100 cp and the surface tension is 20 to 55 mN / m at the head temperature at the time of ink ejection. It is preferable to use, More preferably, the ink viscosity is 1-50cp and surface tension is 20-45mN / m, More preferably, the ink viscosity is 1-20cp and surface tension is 25-35mN / m. The head temperature is preferably 10 to 100 ° C, more preferably 35 to 85 ° C from the viewpoints of leveling properties of the ink dots, adhesion to the light guide member, accurate arrival position stability of the ejected ink, and the like. Preferably it is the range of 40-60 degreeC.

In the case where the light absorption band is formed by the inkjet method or the like, the head speed is preferably 10 to 1000 mm / sec from the viewpoint of shortening the tact time, leveling property of the ink dot, adhesion to the light guide member, and the like. More preferably, it is 200-800 mm / sec, More preferably, it is the range of 250-500 mm / sec.

In the present invention, as the first and second light absorption bands 36 and 136, those containing fine particles of light diffusivity or light absorption can be used. 20 micrometers or less are preferable, More preferably, it is 14 micrometers or less, Especially preferably, it is 8 micrometers or less. Such microparticles | fine-particles can be contained 10-125 weight% with respect to 100 weight part of porcelain solid content except this microparticle. As light-absorbing microparticles | fine-particles, what consists of black polymer type microparticles | fine-particles, such as an acrylic resin containing carbon black, a styrene resin, a (meth) acryl / styrene copolymer resin, and a benzoguanamine resin, etc. can be illustrated. Examples of the light diffusing fine particles include polymer fine particles such as acrylic resin, styrene resin, (meth) acrylic / styrene copolymer resin and silicone resin, and inorganic fine particles such as silica, alumina and calcium carbonate. The light diffusing fine particles may use light diffusion due to surface reflection, or may be light transmitting and use light diffusion due to refraction of internally transmitted light. The light absorbing fine particles contribute to the improvement of the light absorption of the light absorption bands 36 and 136, and the light diffusing fine particles indirectly improves the light absorption by performing light diffusion in the light absorption bands 36 and 136. It contributes to the averaging by diffusion of the light emitted without being absorbed.

15, the embodiment of the 1st light absorption band 36 containing light diffusable or light absorbing microparticles | fine-particles is shown. In this embodiment, fine irregularities are formed on the surface of the light absorption band 36. The convex part 37 of this unevenness | corrugation is formed by the light diffusable or light absorbing microparticles | fine-particles 38 contained in the light absorption band 36. As shown in FIG. This unevenness | corrugation is made to contain the light diffusable or light absorbing microparticles | fine-particles 38 in the ceramic material which comprises the light absorption band 36, and it can form according to coating film formation. By forming fine irregularities on the surface of the light absorption band 36 in this way, unnecessary light can be made less noticeable. That is, as described above, when a part of the light generated from the primary light source 1 reaches the light absorption band 36 without being reflected from the light source reflector 22 and reaching the light incident end face 31, here, Placenta is absorbed. At this time, the remaining light is reflected toward the light guide light exit surface 33, but the reflected light is diffusely reflected by the unevenness of the surface of the light absorption band 36, which makes it inconspicuous. Also in the 2nd light absorption band 136, the same form is suitable.

In FIG. 16, the enlarged view of the boundary part of the light output surface 33 of the light guide 3 and the light incident end surface 31 is shown. The edge portion that forms the boundary between the light exit surface 33 and the light incident end face 31 (the same as for the edge portion that forms the boundary between the back surface 34 and the light incident end face 31) is ideally formed at approximately right angles. However, in reality, the processing is often a curved surface with a small radius of curvature. In particular, when the light incident end surface 31 is formed by cutting as described above, the synthetic resin of the light guide material is partially melted by the process, so that the light exit surface 33 and the light incident end surface 31 are separated. The edge portion of the boundary may be curved based on the surface tension. From the viewpoint of the prevention of the lowering of the luminance uniformity, such as the prevention of the bright line generation, the radius of curvature R of the edge portion is preferably 50 µm or less. If the radius of curvature R of this edge portion is too large, light incidence at the edge portion becomes remarkable, and this portion acts like a convex lens, and abnormal light is emitted from the light guide 3, or the first and second This is because there is a risk of reducing the effect of preventing the occurrence of bright lines caused by the light absorption bands 36 and 136 and the effect of preventing the occurrence of sudden local brightness changes. The radius of curvature R of the edge portion is more preferably 10 µm or less, particularly preferably 5 µm or less.

17 shows the light exit surface 33 and the light incident end surface 31 when the light incident end surface 31 and the side edge close to the light incident end surface of the first light absorption band 36 are simultaneously formed by cutting. An enlarged view of the border is shown. The surface tension of the radius of curvature R (corresponding to the protrusion 39 above) is formed at the edge portion of the boundary between the light exit surface 33 and the light incident end surface 31 by the surface tension, and the first light absorption band ( The edge of 36) is positioned to expose a portion of the light guide edge portion. The exposed portion of the light guide edge portion constitutes the light incident end face 31.

Fig. 19 is a schematic perspective view showing one embodiment of the surface light source device according to the present invention, and Figs. 35 and 36 are partial perspective views and partial bottom views of the light guide body. In these drawings, the same reference numerals are attached to the same, corresponding, or related members as in FIGS. 1 to 18. As stated below, in this embodiment, the light absorption band 36 is formed in the back surface 34 of the light guide 3.

In the back surface 34 of the light guide 3, a substantially flat surface region 137 having a width WP extending along the light incident end surface 31 is formed in the vicinity of the light incident end surface 31. This substantially flat surface area 137 may be a smooth surface, or may be roughened (that is, become a mat surface). In the substantially flat surface region 137, prismatic columns (in Fig. 36, the ridges and the curves thereof are indicated by numerals 34a and 34b, respectively) formed over most of the region of the back surface 34 are not formed. It is not. The substantially flat surface region 137 is at a height position (Z-direction position) that is substantially equal to the curve 34b of the prism row. The width WP of the substantially flat surface region 137 is, for example, 50 µm to 1000 µm, and is preferably about the same as or slightly larger than the width W of the light absorption band 36. In this substantially flat surface region 137, a light absorption band 36 extending along the light incident end face 31 is formed. The light absorption band 36 can be formed, for example, by applying a black ceramic material. In order to improve the adhesiveness or fixability of the ceramic material in this ceramic material application, it is preferable that the rough flat surface area | region 137 is roughened.

Although the application of the light absorption band 36 is not specifically limited, It is especially preferable by inkjet printing, screen printing, tempo printing, or thermal transfer printing as demonstrated in the actual form other than the said FIG. In addition, as a material of the light absorption band 36, what was demonstrated in embodiment other than said FIG. 1 is mentioned.

This light absorption band absorbs a part of the light introduced into the light guide 3 from the light incident end face 31, and prevents the generation of bright lines in the vicinity of the light incident end face 31. Therefore, the visible light transmittance (JIS-K7105B) is, for example, 0% to 90%, preferably 0% to 60%, further preferably 2% to 45%, and particularly preferably 4% to 30%. Moreover, it is preferable that the reflectance (JIS-K7105B) of the light absorption band 36 is 0 to 20%, More preferably, it is 0 to 15%. In addition, although it is thought that the light beam generation also contributes to the light which flows into the light guide body from the back surface 34 by the reflection by the light source reflector 2 without passing through a light incident cross section, the light absorption band 36 absorbs a part of this light, Prevent occurrence.

In the present embodiment, the width WT is formed between the region where the prism rows are substantially formed in the light guide surface 34 (ie, the prism row forming surface region 139) and the substantially flat surface region 137. Transition region 138 is formed. In this transition area 138, the transition from the side close to the prism row forming surface region 139 to the side near the flat surface region 137 and the transition from the prism row forming surface to the substantially flat surface are made gradually. The width WT of the transition region 138 is, for example, 50 µm to 2000 µm.

In this embodiment, since the light absorption band 36 is formed in the substantially flat surface area | region 137 in which the prism row is not formed, when a light absorption band 36 is given by printing or application | coating etc., a ceramic material is an adjacent prism. There is almost no such thing as leaching in the prism row forming surface region 139 by the grooves between the rows, and the light absorption band 36 having a predetermined width can be reliably formed, and the surface light source device having good optical performance can be stably You can get it.

20 is a schematic bottom view showing the light guide 3 together with the primary light source 1. As shown in FIG. 20, the light absorption band 36 does not shield light incident from the light incident end face 31, but reduces the luminance due to a decrease in the amount of incident light and shields light to be guided. In order to suppress generation | occurrence | production of a dark line, it is necessary to be formed only in the back surface 34 of the light guide 3, and not to form in the light incident end surface 31. FIG. The light absorption band 36 has a width (X direction dimension) of W, and the distance between the side edge near the light incident end face 31 and the light incident end face 31 of the two side edges defining the width is W. D. Width W is 50-1000 micrometers, Preferably it is 50-800 micrometers, More preferably, it is 100-700 micrometers, Especially preferably, it is 200-400 micrometers. If the width W is less than 50 µm, the effect of preventing the occurrence of necessary bright lines tends to decrease, and if the width W exceeds 100 µm, dark lines tend to occur or the overall luminance decreases. The width W is preferably 0.4 times or less, more preferably 0.3 times or less, and particularly preferably 0.2 times or less of the thickness at the light incident end surface position of the light guide 3. Moreover, if the distance D is 300 micrometers or less, the above-mentioned bright line generation prevention effect can be obtained, Preferably it is 200 micrometers or less, Especially preferably, it is 100 micrometers or less.

In forming the light absorption band 36 in the back surface 34 of the light guide 3, a recess is formed in at least one part of the light absorption band formation site of the back surface 34, and a coating material etc. are apply | coated to this recess, and light You may form an absorption band. That is, as shown in FIG. 24 and FIG. 25, the recessed part 70 of a cross-sectional triangle or a lenticular shape, for example in the back surface 34 is 150 micrometers or less in depth, Preferably it is 100 micrometers, for example. Hereinafter, the light absorption band 36 is preferably formed to have a depth of 50 μm or less, and to include the inside of the recess. If the depth of the concave portion 70 is too large, the waveguide mode in the light guide is lost, and dark lines easily appear.

As the light guide 3, it is not limited to the shape shown in FIG. 19, The thing of various shapes, such as a wedge shape with a thick light incident cross section, can be used.

21 and 22, an example of the manufacturing method of the above light guide is described.

FIG. 21: is a typical bottom view which shows the light-guide material 3 'obtained by apply | coating the ceramic material shape | molded by the resin molding process and becoming a light absorption band. When the light guide material 3 'shows a part corresponding to each part of the light guide 3 finally obtained as a counterpart, the light incident end face counterpart 31', the back counterpart 34 ', and Light absorption band counterpart 36 '. Required prism rows are formed in the back surface counterpart 34 '. The mat surface as a rough surface which comprises a required light output mechanism is formed in the light output surface corresponding part on the opposite side. The light absorption band corresponding part 36 'is formed in the substantially flat area | region which adjoins the light-incidence cross-section corresponding part 31' of the back surface responding part 34 '.

As shown in Fig. 22, by cutting the light incident end face corresponding portion 31 'and cutting out unnecessary portions, the light incident end face 31 is formed as the cut surface, and at the same time the light absorption band 36 ) Is formed. Thus, the light generated from the primary light source 1 can be configured to easily enter the light incident end face 31 up to the boundary with the light exit surface 33. As shown in Figs. 21 and 22, the light absorption band corresponding portion 31 'is formed even in an unnecessary portion cut out by cutting, and the light incident cross section corresponding to the light absorption band corresponding portion 31' is formed in the cutting process. By simultaneously cutting off the side edge close to the portion 31 ', the distance D is easily set to 0 µm, and the light incident end surface 31 reaches the boundary with the light exit surface 33. The light generated from the primary light source 1 can be configured to enter.

The light emitting surface of the device which is a surface light source composed of the primary light source 1, the light source reflector 2, the light guide 3, the light deflecting element 4, the light diffusing element 6 and the light reflecting element 5 as described above. [The liquid crystal display element LC as a backlight is comprised by arrange | positioning liquid crystal display element LC on the emission surface 62 of the light-diffusion element 6, as shown in FIG. In FIG. 23, the dot-shaped light absorptive ceramic material of the disperse arrangement which comprises the dot pattern part of the light-diffusion element 6 is shown with the code | symbol 64 '. The liquid crystal display device is passed through the liquid crystal display element LC from above in FIG. 23 and observed by an observer. The display area of the liquid crystal display device is determined by the display area of the liquid crystal display element LC or the opening area of the frame holding the liquid crystal display element. The effective light emitting area of the surface light source device is larger than the display area of the liquid crystal display device and exists to cover all of the display areas. The light absorption band 36 is disposed outside the display area and positioned outside the effective light emission area.

The case where the said distance D is 0 micrometer in the light guide 3 is shown by FIG. As shown, the light absorption band 36 extends to the boundary with the light incident end face 31, but does not extend to the light incident end face 31. That is, the light incident end surface 31 is comprised so that the light which generate | occur | produces from the primary light source 1 may enter into the boundary with the back surface 34. As shown in FIG.

Moreover, the light source reflector 2 is arrange | positioned so that the edge part may cover the light absorption band 36. As shown in FIG. An area of about 2 to 4 mm in width of the outer circumference of the light emitting surface of the surface light source device is covered by a frame, and no light is emitted to the outside from this area (frame-shaped area). The edge of the light source reflector 2 is located in the frame frame region, and therefore, the light absorption band 36 is located in the frame frame region, that is, outside the effective light emitting region of the surface light source device.

Of the light introduced from the light incident end face 31 into the light guide 3, the light L1 reaching the light absorption band 36 is absorbed by the light absorption band. The rest is reflected from the back surface 34 to become light L2 traveling in the light guide. This light L2 exits from the light exit surface 33. In the present invention, the light L2 can be sufficiently weaker than the light L1 by the light absorption in the light absorption band 36, and therefore, it rarely causes a bright line. For example, if the light absorption band 36 does not exist, the intensity of this light L2 becomes quite strong. This light L2, that is, the reflected light at the portion where the light absorption band 36 is attached in the present invention is the biggest cause of the bright line generation, and when the light absorption band 36 does not exist, the bright line is noticeably generated.

In addition, part of the light generated from the primary light source 1 is reflected by the light source reflector 2 and reaches the light absorption band 36 without reaching the light incident end face 31, where most of it is absorbed. . For example, if the light absorption band 36 does not exist, light flows into the light guide from the back surface 34 of the portion where the light absorption band 36 is attached in the present invention. This light is also a cause of the above-mentioned bright line, and also in this point, when the light absorption band 36 does not exist, the bright line is generated.

In the present invention, since light of a narrowly collimated luminance distribution (in XZ plane) sufficiently collimated can be incident on the liquid crystal display element LC from a device serving as a light source, it is bright without uniformity of gray level in the liquid crystal display element and uniform in color. It is possible to obtain an image display having good sex, and to obtain light irradiation concentrated in a desired direction, and to improve the utilization efficiency of the amount of emitted light of the primary light source 1 for illumination in this direction.

In the description of the above embodiment, the light absorption band 36 has been described as having almost uniform light absorption characteristics in the width direction. However, in the present invention, the light absorption band may be changed in the width direction. As a preferable aspect of such a light absorption characteristic, what is formed so that the side edge side farther than the side edge close to the light incident cross section of the light absorption band 36 may have high visible light transmittance. By doing so, a sudden change in the light absorbency at the boundary between the light absorption band 36 and the region of the light guide back surface 34 on which it is not formed can be prevented, and the occurrence of luminance nonuniformity can be further reduced.

For example, as shown in FIG. 26, the light absorption band 36 is positioned in the second region 36-2 far from the first region 36-1 near the light incident cross section with respect to the width direction (X direction). The visible light transmittance T2 of the second region 36-2 is reduced by setting the thickness of the first region 36-1 to about twice the thickness of the second region 36-2. It can be made higher than the visible light transmittance T1 of one area | region 36-1. The light absorption band 36 in which the visible light transmittance is changed in two stages is first applied with a uniform thickness to both the first region 36-1 and the second region 36-2, and thereafter. It can be obtained by performing additional ceramic coating only in the first region 36-1. Similarly, the light absorption band in which the visible light transmittance changes in three or more steps can be formed.

In addition, as shown in FIG. 27, the thickness of the light absorption band 36 is gradually reduced over the side edge away from the side edge close to the light incident end face 31 with respect to the width direction (X direction) of the light absorption band 36. Thus, the visible light transmittance of the light absorption band 36 may be continuously changed in the width direction of the light absorption band 36. The light absorption band 36 of this form can be obtained by performing a ceramic coating while moving a mask member from the side closer to the light incident end surface 31 in the X direction. The continuous change in the visible light transmittance in the light absorption band 36 does not need to span the entire width direction, but may be part of the width direction.

The change in the visible light transmittance in the light absorption band 36 may be a combination of the step change described with reference to FIG. 26 and the continuous change described with reference to FIG. 27.

As for the visible light transmittance of the light absorption band 36, it is preferable that the lowest value exists in the range of 0%-60%, and the highest value exists in the range of 40%-90%. By being in this range, generation | occurrence | production of a dark line can fully be prevented, maintaining the prevention effect of a bright line generation, and generation | occurrence | production of a luminance nonuniformity can be reduced.

28 and 29, further another example of the above-described method for manufacturing the light guide will be described. (A) and FIG. 29 (a) are partial bottom views, and FIG. 28 (b) and FIG. 29 (b) are partial sectional views of the XZ.

First, as shown in FIG. 28, in the area in the substantially flat surface area 137 of the back surface 34 of the light guide 3, the distance from the light incident end surface (close to the light incident end surface 31) ( In the region of the width W 'provided with D'), the ink dots 36A that are independent or partially continuous with each other are formed by the inkjet method. As an apparatus used for implementation of the inkjet method, the printer of the continuous (continuous injection) system and the DOD (dot on demand) system using a piezo nozzle is illustrated. By these apparatuses, ink is ejected from a plurality of nozzles, and the light guide 3 is scanned in a predetermined direction parallel to the back surface 34 with respect to the nozzle as necessary, thereby being shown in a predetermined region on the back surface. The same plurality of ink dots 36A which are independent of each other are formed. All of these ink dots may be completely independent as shown, but some of them may partially overlap and continue.

Next, adjoining ones of the ink dots are combined to form a continuous ink layer (hereinafter referred to as "leveling"). This leveling is carried out for the time required to obtain the required leveling amount. Thereby, as shown in FIG. 29, the adjacent ink layers are bonded to each other, and the ink layer (continuous over the entire area of the width W at a distance D from the light incident end surface 31 ( 36B). The area of the width W includes all of the areas of the width W ', and the width W is slightly larger than the width W' by the leveling.

Next, the light absorption band 36 is formed by hardening the ink layer 36B.

As the ink, for example, an ultraviolet curable ink as described in the embodiment other than FIG. 1 may be used. As described in the embodiment other than FIG. 1, by controlling the bonding state of the ink dots in the ink layer 36B as desired by the leveling time, the surface state of the light absorption band 36, that is, the degree of irregularities, is controlled. Can be controlled. Proper irregularities are formed on the surface of the light absorption band 36, so that unnecessary light can be made less noticeable. That is, as described above, when a part of the light generated from the primary light source is reflected from the light source reflector 22 and reaches the light absorption band 36 without reaching the light incident end face 31, the placenta is absorbed here. do. At this time, the remaining light is reflected on the rear surface of the light guide body 34, but the reflected light is diffusely reflected by the unevenness of the surface of the light absorption band 36, so that it can be made inconspicuous.

In order to perform the formation of the light absorption band 36 as described above well, the existence of the substantially flat surface region 137 is important. That is, since the substantially flat surface region 137 having a width WP of 50 µm or more exists, the ceramic material is applied to this region, leveled and cured, and the light absorption band 36 having a required width extending along the light incident end surface 31 is provided. ) Becomes easy to form. Here, even when the ceramic material leaches into the prismatic valleys during application and leveling, the leaching can be prevented from becoming excessive. The width of the light absorption band 36 can be controlled by adjusting the viscosity, coating amount, and the like of the ceramic material used, whereby the light guide for the surface light source device having good optical performance can be stably obtained. When the width WP of the substantially flat surface area 137 is less than 50 μm or when the approximately flat surface area 137 does not exist, the ceramic material directly adheres unevenly to the slopes of the prism rows, and the ceramic material does not arrive. A part appears, and uniform leveling tends to be difficult. Thereby, it becomes difficult to form the light absorption band of required width | variety, light absorption becomes inadequate, and it exists in the tendency for the effect of the prevention of the bright line generation in the vicinity of the light-incidence end surface 31 to become difficult to obtain.

A further separate example of the method of manufacturing the light guide as described above will be described with reference to FIG. 30.

In this example, first, the light guide material 3 'as shown in Fig. 30A is prepared. Next, as shown in FIG. 30 (b), the light incidence end face 31 is formed by cutting the light incidence end face corresponding portion 31 '. By this cutting process, a projection projecting toward the rear surface 34 (that is, protruding from the other area of the substantially flat surface area of the rear surface 34) at the boundary between the light incident end surface 31 and the rear surface 34. 39 is formed. The protruding portion 39 extends along the boundary line between the light incident end face 31 and the back surface 34, that is, along the light incident end face 31. This protrusion 39 can be formed by cutting as described above, but may be formed by molding at the time of injection molding.

Next, as shown in Fig. 30C, an ink dot 36A is formed in a required area of the back surface 34 (area in the substantially flat surface area 137). This ink dot is formed as described with reference to FIG. 28 above. Next, leveling of the ink dots is performed, and as shown in FIG. 30 (d), the ink layer 36B is formed in the required area of the back surface 34. This ink layer is formed as described above with reference to FIG. 29, but here, the side edges close to the light incident end face 31 of the ink layer 36B formed by leveling reach the protrusions 39. FIG. The position of the ink dot formation area is set. That is, the area | region in which the ink dot 36A shown in FIG. 30 (c) is formed is slightly separated from the light incident end surface 31. FIG. Thereby, the ink flowing at the time of leveling of the ink dot prevents the projection 39 from moving to the light incident end surface 31.

Finally, the ink absorption zone 36 is formed by curing the ink layer 36B.

According to the above method, it is easy to form the light absorption band 36 extremely close to the light incident end face 31 without having to follow the light incident end face 31. According to this light absorption band 36, reduction of the amount of light which injects into the light guide 3 from the light incident end surface 31 can be suppressed.

In order to facilitate the action at the proper position of the movement of the ink to the light incident end face 31 by the protrusions 39, and to facilitate the formation of the protrusions 39, the dimensions of the protrusions 39 are as follows. It is preferable to be in the appropriate range, such as. That is, as shown in FIG. 34, the height of the protrusion 39 (height in another area of the substantially flat surface region of the back surface 34) is H, and the height of the protrusion 39 in the XZ cross-sectional shape is determined. The full width at half maximum of height is referred to as W. Preferably, H is 1 to 50 µm, more preferably 2 to 30 µm, more preferably 5 to 20 µm, and W is 1 to 50 µm, more preferably. Is 2-30 micrometers, More preferably, it is 5-20 micrometers. When the protrusion height H is too small, the action of the ink movement blocking tends to be insufficient. When the protrusion height H is too large, the assembly of the surface light source device becomes difficult, or the distortion of the protrusion is likely to occur. It also tends to be difficult to move the ink to near the top of the protrusions. In addition, when the height half width W is too small, it is difficult to form protrusions, and the mechanical strength is lowered, and the action of ink movement retardation tends to be uncertain, and the height half width W is too large. There is a tendency that assembling becomes difficult and it becomes more difficult to move the ink to the vicinity of the top of the protrusion.

In any of the methods described above, the ultraviolet curable ink which is a porcelain for forming the light absorption band 36 contains (meth) acrylate monomer and / or an organic solvent as described in the embodiment of FIG. It is preferable to use an ultraviolet curable ink. In addition, as the light absorption band 36, those containing fine light diffusing or light absorbing fine particles as described in the embodiments other than FIG. 1 can be used.

31 shows an embodiment of a light absorption band 36 containing light diffusing or light absorbing fine particles. In this embodiment, the minute unevenness | corrugation which was demonstrated in embodiment other than said FIG. 1 is formed in the surface of the light absorption band 36. FIG. The convex part 37 of this unevenness | corrugation is formed by the light diffusable or light absorbing microparticles | fine-particles 38 contained in the light absorption band 36. As shown in FIG. This unevenness | corrugation is made to contain the light diffusable or light absorbing microparticles | fine-particles 38 in the ceramic material which comprises the light absorption band 36, and it can form according to coating film formation. By forming fine irregularities on the surface of the light absorption band 36 in this way, unnecessary light can be prevented from being noticed further. That is, as described above, most of the light generated from the primary light source 1 is reflected from the light source reflector 22 and reaches the light absorption band 36 without reaching the light incident end face 31. Is absorbed. At this time, the remaining light is reflected on the light guide surface 34 side, but the reflected light is diffusely reflected by the unevenness of the surface of the light absorption band 36, which makes it inconspicuous.

FIG. 32 shows an enlarged view of the boundary between the back surface 34 of the light guide 3 and the light incident end face 31. The edge portion that forms the boundary between the back surface 34 and the light incident end surface 31 (the same as for the edge portion that forms the boundary between the light exit surface 33 and the light incident end surface 31) is ideally almost Although it forms a right angle, in reality, in many cases, it is made into the curved surface of a minute curvature radius according to a process. In particular, in the case where the light incident end surface 31 is formed by cutting as described above, the synthetic resin of the light guide material is partially melted by the process and the boundary between the back surface 34 and the light incident end surface 31 is formed. The edge portion of may become a curved surface based on the surface tension. From the viewpoint of the prevention of the lowering of the luminance uniformity, such as the prevention of the bright line generation, the radius of curvature R of the edge portion is preferably 50 µm or less. If the radius of curvature R of this edge portion is too high, light incidence from the edge portion becomes remarkable, and this portion acts like a convex lens, and abnormal light is emitted from the light guide 3, or the light absorption band 36 It is because there exists a possibility that the effect of preventing the generation | occurence | production of the bright wire by this may be reduced. The radius of curvature R of the edge portion is more preferably 10 µm or less, particularly preferably 5 µm or less.

33, enlargement of the boundary part between the back surface 34 and the light incident end surface 31 when the light incident end surface 31 and the side edge close to the light incident end surface of the light absorption band 36 were formed simultaneously by cutting. Shows a figure. The surface tension of the curvature radius R (corresponding to the protrusion 39 above) is formed at the edge portion of the boundary between the back surface 34 and the light incident end surface 31 by the surface tension, and the edge of the light absorption band 36 is formed. It is positioned to expose a part of the light guide edge portion. The exposed portion of the light guide edge portion constitutes the light incident end face 31.

It is a typical partial bottom view which shows one Embodiment of the light guide for surface light source devices which concerns on this invention. In this figure, the same code | symbol is attached | subjected to the member or part which has a function similar to the said FIG. 19-36. FIG. 47 is a view corresponding to FIG. 36.

In the present embodiment, the light absorption band 36 is formed so as to cover the entirety of the substantially flat surface region 137 of the width WP on the rear surface of the light guide and also cover a part of the transition region 138. Since the porcelain applied when forming the light absorption band 36 flows along the valleys of the prism rows and advances farther than in the portions other than the valleys, the far side farther from the light incident end face 31 of the light absorption zone 36. Becomes a zigzag shape. Thereby, the gradation effect in the light absorptivity of the light absorption band 36 is exhibited, and generation | occurrence | production of a luminance nonuniformity can be reduced further. However, when the width of the short zigzag shape farther from the light incident end face 31 of the light absorption band 36 becomes too large, inclusion of a dark band may occur, so it is preferable to be 300 탆 or less.

Next, even in the case of using a reflector which is a light source having strong specular tendency in combination with the primary light source, it is easy to prevent the generation of bright lines in the vicinity of the light incident cross section and to prevent the sudden occurrence of a sudden brightness change. An embodiment of the surface light source device is shown. As a material of the light source reflector with a strong tendency for regular reflection, the plastic film which has a metal vapor deposition reflective layer on the surface can be used, for example.

37 is a schematic perspective view showing one embodiment of the surface light source device according to the present invention. In this figure, the same code | symbol is attached | subjected to the member or part which has a function similar to the said FIG. 19-36.

In this embodiment, two light absorption bands are provided. That is, on the light guide surface 34, the light incident end surface 31 is larger than the light absorption band 36, except for the light absorption band similar to the embodiment of Figs. 19 to 36 (" first light absorption band "; 36). 2nd light absorption band 136 extended along the light-incidence end surface 31 in the position far from (). That is, on the back surface 34 of the light guide, the first light absorption band 36 and the second light absorption band 136 extending along the light incident end face 31 are arranged in this order from the side close to the light incident end face 31. Is arranged. These 1st and 2nd light absorption bands 36 and 136 can be formed by apply | coating a black ceramic material like the light absorption band 36 of embodiment of FIGS. 19-36, for example.

The second light absorption band 136 is received from the light exit surface 33 into the light guide 3 by the light introduced from the light incident end face 31 into the light guide 3 or by the reflection by the light source reflector 2. By absorbing a part of the light, the first light absorption band 36 prevents the generation of bright lines and reduces the luminance in the region near the region where the luminance is lowered. This prevents the occurrence of bright lines by the first light absorption band 36, thereby preventing the occurrence of a sudden sharp change in the luminance in the region where the luminance is reduced and in the vicinity of the region. In order to satisfactorily realize such a brightness adjusting action of the second light absorption band 136, the visible light transmittance of the second light absorption band 136 is preferably higher than the visible light transmittance of the first light absorption band 36. The reason for this is as follows. The cause of the bright lines involved in the second light absorption band 136 is generally light introduced into the light guide 3 from the light incident end face 31, or a reflection path light exit surface by the reflector 2 which is a light source. A part of the light received from the light guide 3 from 33 is totally reflected on the back surface 34, and the light guide light emitting surface 33 is in the effective light emitting area of the surface light source device and in the display area of the liquid crystal display device. It is reflected in. These bright lines are generally weak light bands having a larger magnification than the bright lines in which the first light absorption band 36 is involved, and the first light absorption band 36 is used to improve the sudden change in luminance and to make a smooth output light distribution. It is suitable to use a light absorption band having a transmittance higher than that of (). In addition, since the second light absorption band 136 is located at a position away from the light guide end face 31 of the light guide than the first light absorption band 36, the second light absorption band 136 significantly loses the mode of light guiding the inside of the light guide, and thus, is located within the effective light emission region. In addition, there is a high risk of causing uneven luminance of dark lines or dark bands in the display area. Also from this viewpoint, it is preferable to use the thing with high visible light transmittance (low visible light transmittance) as the 2nd light absorption band 36. FIG. The visible light transmittance (JIS-K7105B) of the second light absorption band 136 is, for example, 40 to 95%, preferably 60 to 90%, and more preferably 70 to 90%. In the state where the light source reflector is arranged, the reflectance (JIS-K7105B) of the second light absorption band 36 is preferably 40 to 95%, preferably 60 to 90%, and more preferably 70 to 90%. 90%.

The thickness of the light guide 3 is, for example, about 1.5 to 4 mm, preferably 2 to 3 mm in the vicinity of the light incident end face 31.

FIG. 38 is a schematic bottom view of the light guide 3 together with the primary light source 1. As shown in FIG. 38, the first light absorption band 36 does not block light incident from the light incident end face 31, but is caused by a decrease in luminance due to a decrease in the incident light or light blocking of light to be guided. In order to suppress generation | occurrence | production of a dark line, it is necessary to be formed only in the back surface 34 of the light guide 3, and not to form in the light incident end surface 31. FIG. Further, the first light absorption band 36 has a width (X direction dimension) of W1, and the side edge on the side closer to the light incident end face 31 and the light incident end face 31 of the two side edges defining the width thereof. The distance to is D1. Width W1 is 50-800 micrometers, Preferably it is 100-500 micrometers, Especially preferably, it is 150-400 micrometers. If the width W1 is less than 50 µm, the effect of preventing the occurrence of necessary bright lines tends to be lowered. If the width W1 exceeds 800 µm, dark lines are generated or the overall luminance decreases. The width W1 is preferably 0.4 times or less, more preferably 0.3 times or less, and particularly preferably 0.2 times or less of the thickness at the light incident end surface position of the light guide 3. Moreover, if the distance D1 is 300 micrometers or less, the above-mentioned bright line generation prevention effect can be acquired, Preferably it is 200 micrometers or less, Especially preferably, it is 100 micrometers or less.

On the other hand, the second light absorption band 136 has a width (X direction dimension) of W2, and the side edge near the light incident end face 31 and the light incident end face 31 of the two side edges defining the width thereof. The distance to is D2. Width W2 becomes like this. Preferably it is 50-800 micrometers, More preferably, it is 100-700 micrometers, Especially preferably, it is 150-600 micrometers. If width W2 is less than 50 micrometers, the required brightness adjustment effect will fall, and if width W2 exceeds 800 micrometers, there exists a tendency for the fall of the whole brightness | luminance and the reflection of a rock band generate | occur | produce. In addition, if the distance D2 is in the range of 500-3000 micrometers, said brightness adjustment effect can be obtained, Preferably it is in the range of 700-2000 micrometers, Especially preferably, it is in the range of 900-1500 micrometers.

19 to 36, as described with reference to FIGS. 24 and 25 with respect to the first light absorption band 36, the second light absorption band 136 also has a second side of the back surface 34. A recessed part may be formed in at least one part of the light absorption band formation site | part, and a coating material etc. may be apply | coated to this recessed part, and a 2nd light absorption band may be formed.

39 and 40, an example of the manufacturing method of the light guide as described above will be described. These figures correspond to FIG. 21 and FIG. 22, and the same code | symbol is attached | subjected to the member or part which has a function similar to FIG. 21 and FIG. 39, required prism rows are formed in the back surface counterpart 34 '. The mat surface as a rough surface which comprises a required light output mechanism is formed in the light output surface corresponding part on the opposite side. In a substantially flat area proximate to the light incident end face correspondence portion 31 'of the back surface correspondence portion 34', away from the first light absorption band correspondence portion 36 'and the first light absorption band correspondence portion 36'. A second light absorption band counterpart 136 'is formed. As shown in Fig. 40, by cutting the light incident end face corresponding portion 31 'and cutting unnecessary portions, the light incident end face 31 is formed as the cut surface, and at the same time the first light absorption band ( 36) is formed. The second light absorption band counterpart 136 'can be used as the second light absorption band 136 as it is.

The light emitting surface of the surface light source device comprising the primary light source 1, the light source reflector 2, the light guide 3, the light deflecting element 4, the light diffusing element 6 and the light reflecting element 5 as described above [ The liquid crystal display device having the surface light source device of the present invention as a backlight is configured by disposing a liquid crystal display element LC on the exit surface 62 of the light diffusion element 6 as shown in FIG. This figure corresponds to FIG. 23, and the same reference numerals are attached to members or portions having the same functions as in FIG.

In FIG. 41, the case where the said distance D1 is 0 micrometer in the light guide 3 is shown. As shown, the first light absorption band 36 extends to the boundary with the light incident end face 31, but does not extend to the light incident end face 31. That is, the light incident end surface 31 is comprised so that the light which generate | occur | produces from the primary light source 1 may enter into the boundary with the back surface 34. As shown in FIG.

In addition, the light source reflector 2 is arrange | positioned so that the edge part may cover the 1st and 2nd light absorption bands 36 and 136 via the light reflection element 5. However, the end edge part of the light source reflector 2 may be arrange | positioned inside the light reflection element 5, and may cover the 1st and 2nd light absorption bands 36 and 136 directly. In addition, the light source reflector 2 may not cover the second light absorption band 136. An area of about 2 to 4 mm in width of the outer circumference of the light emitting surface of the surface light source device is covered by the frame, and no light is emitted from the area (frame-shaped area) to the outside. The end edge portion of the light source reflector 2 is located in the frame shape region, and therefore, the first and second light absorption bands 36 and 136 are located in the frame shape region, that is, outside the effective light emitting region of the surface light source device. However, the second light absorption band 136 may be located outside the frame-shaped area, that is, within the effective light emitting area of the surface light source device.

Most of the light L1 reaching the first light absorption band 36 among the light introduced from the light incident end face 31 into the light guide 3 is absorbed by the first light absorption band. The rest is reflected from the back surface 34 to become light L2 traveling in the light guide. This light L2 exits from the light exit surface 33. In the present invention, the light L2 can be sufficiently weaker than the light L1 by the light absorption in the first light absorption band 36, and therefore, hardly causes the bright line. For example, if the first absorption band 36 does not exist, the intensity of this light L2 becomes quite strong. This light L2, i.e., the reflected light at the portion where the first light absorption band 36 is attached in the present invention, is the biggest cause of the bright line generation, and the visible bright line when the first light absorption band 36 does not exist. This happens.

In particular, when the light source reflector 2 or the light reflecting element 5 is used having a strong specular tendency, when the first light absorption band 36 does not exist, a part of the light in the light guide 3 Reflected by the reflector 2 or the light reflecting element 5 which is a light source passing through the back surface 34 (in FIG. 41, the light reflecting element 5 is disposed inward of the end edge of the light source reflector 2, Therefore, the light reflecting element 5 is specularly reflected by the light reflecting element 5, but when the edge of the light reflector 2 is disposed inward of the light reflecting element 5, it is specularly reflected by the light reflecting element 2], and the back surface 34 again. Since it penetrates and is introduced into the light guide 3, an unusually visible bright line is generated based on this. In order to prevent the occurrence of such unusually noticeable bright lines, it is preferable to use a low visible light transmittance as the first absorption band 36. However, in the case where the occurrence of noticeable bright lines by the first light absorption band 36 is prevented in this way, the luminance of the region where the bright lines are reduced decreases excessively compared with the luminance of the region in the vicinity thereof, The contrast of the luminance becomes large (that is, a sudden sudden change in luminance occurs), and the hidden line removal region may be viewed as a dark line, or may be viewed as a hidden line even when the region near the reduced line area is weak. In other words, even if the visible bright lines are removed, there is a sudden sudden change in luminance, which may reduce the quality of the display image when used as a backlight of the display device.

In this invention, by arrange | positioning the 2nd light absorption band 136, luminance of the area | region in the vicinity of a bright line reduction area | region is adjusted brightness so that the difference with the brightness of a bright line reduction area | region may become small, and a locally abrupt brightness change in these areas is carried out. Is prevented from occurring, that is, the luminance contrast in these areas is not increased. Therefore, the bright line reduction area is not visually recognized as the dark line or the area in the vicinity thereof is visually recognized as the bright line.

That is, of the light L3 which reaches the 2nd light absorption band 136 among the light introduce | transduced into the light guide 3 from the light incident end surface 31, the placenta is absorbed by the said 2nd light absorption band. The rest of the light is reflected from the back surface 34 to become light L4 traveling in the light guide. This light L4 exits from the light exit surface 33. In the present invention, the light L4 can be made sufficiently weaker than the light L3 by the light absorption in the second light absorption band 136. Therefore, the intensity difference with the light L2 is reduced, and therefore There is no significant difference in the luminance in the region where the light L2 is first emitted from the light exit surface and in the region where the light L4 near the first exits the light exit plane (that is, the luminance contrast does not become large). ).

In particular, the light L5 introduced into the light guide 3 from the edge portion that forms the boundary between the light guide light exit surface 33 and the light incident end face 31 and reaches the second light absorption band 136 is applicable. Part of it is absorbed by the second light absorption band. The rest of the light is reflected by the back surface 34 and becomes light L6 traveling in the light guide. This light L6 is emitted from the light exit surface 33. In the present invention, the light L6 can be made weaker than the light L5 by the light absorption in the second light absorption band 136, and therefore, the intensity difference with the light L2 is reduced, and thus the light Luminance in the area where L2 is first emitted from the light exit surface and the area in which the light L6 near the first exits from the light exit surface is not significantly different (that is, the brightness contrast is not large).

In addition, some of the light generated from the primary light source 1 is reflected by the light source reflector 2 and reaches the first and second light absorption bands 36 and 136 without reaching the light incident end face 31. Here, the placenta is absorbed. For example, if the light absorption bands 36 and 136 do not exist, light enters the light guide from the back surface 34 of the portion where the light absorption bands 36 and 136 are attached in the present invention. This light is also a cause of the above-mentioned bright line, and also in this point, when the light absorption bands 36 and 136 do not exist, the bright line is generated.

In the above description, the first and second light absorption bands 36 and 136 have been described as having almost uniform light absorption characteristics in the width direction, but in the present invention, the first and second light absorption bands have the light absorption. The characteristic may change in the width direction. As a preferable aspect of such a light absorption characteristic, what is formed so that the side edge side which is farther from the side edge | side near the light incident cross section of the 1st absorption zone 36 may become high visible light transmittance. By doing so, a sudden change in the light absorbency at the boundary between the region of the first light absorbing band 36 and the light guide body back surface 34 on which it is not formed is prevented, and the occurrence of a sudden sudden brightness change is further reduced. can do. Similarly with respect to the second light absorption band 136, the edges on both sides of the second light absorption band 136 are formed to have a higher visible light transmittance. This prevents the sudden change in the light absorbency at the boundary between the second light absorption band 136 and the region of the light guide back surface 34 on which it is not formed, and further reduces the occurrence of sudden local brightness change. can do.

For example, as shown in FIG. 42, the 2nd area | region 36-2 which makes the 1st light absorption band 36 far from the 1st area | region 36-1 near the light incident cross section with respect to the width direction (X direction). ), And the thickness of the first region 36-1 is approximately twice the thickness of the second region 36-2, so that the visible light transmittance T2 of the second region 36-2 is reduced. It can be made higher than the visible light transmittance T1 of the 1st area | region 36-1. The first light absorption band 36 in which the visible light transmittance is changed in two stages is first applied with a uniform thickness to both the first region 36-1 and the second region 36-2, After that, it is possible to obtain additional porcelain coating only in the first region 36-1. Similarly, the first light absorption band in which the visible light transmittance is changed in three or more steps can be formed.

Similarly with regard to the second light absorption band 136, the first region 136-1, the second region 136-2, and the third region 136 in the order close to the light incident cross section in the width direction (X direction). -3), and the thickness of the second region 136-2 is about three times the thickness of the first and third regions 136-1 and 136-3, whereby the first and third regions Visible light transmittance T2 of (136-1, 136-3) can be made higher than visible light transmittance T3 of the 2nd area | region 136-2. The second light absorption band 136 in which the visible light transmittance is changed in two steps is first applied with a uniform thickness to all of the first to third regions 136-1 to 136-3, and thereafter. It can be obtained by performing further porcelain coating only in the second region 136-2. Similarly, the second light absorption band in which the visible light transmittance is changed in three or more steps can be formed.

In addition, as shown in FIG. 43, the thickness of the first light absorption band 36 is closer to the side edge closer to the light incident end surface 31 in the width direction (x direction) of the first light absorption band 36. By gradually decreasing over, the visible light transmittance of the first light absorption band 36 may be continuously changed in the width direction of the first light absorption band 36. Similarly, by gradually decreasing the thickness of the second light absorption band 136 from the center to both edges in the width direction (X direction) of the second light absorption band 136, the visible light transmittance of the second light absorption band 136 is reduced. The second light absorption band 36 may be continuously changed in the width direction. The first and second light absorption bands 36 and 136 of this type can be obtained by carrying out porcelain coating while moving the mask member from the side closer to the light incident end face 31 in the X direction. The continuous change in the visible light transmittance in the first and second light absorption bands 36 and 136 may be a part of the width direction without necessarily covering the entire width direction.

The change in the visible light transmittance in the first and second light absorption bands 36 and 136 may be a combination of the step change described with reference to FIG. 42 and the continuous change described with reference to FIG. 43.

It is preferable that the lowest light transmittance of the first absorption band 36 is in the range of 0% to 60% and the highest value is in the range of 40% to 90%. The visible light transmittance of the second light absorption band 136 is preferably in the range of 40% to 90% of the lowest value and in the range of 60% to 95% of the highest value. By being in these ranges, generation | occurrence | production of a dark line can be prevented, maintaining the effect of preventing a bright line generation, and generation | occurrence | production of a sudden sharp brightness change can be reduced locally.

44 and 45, further another example of the manufacturing method of the above light guide is demonstrated. These figures correspond to the said FIG. 28 and FIG. 29, and the same code | symbol is attached | subjected to the member or part which has a function similar to FIG. 28 and FIG.

First, as shown in FIG. 44, in the area in the substantially flat surface area 137 of the back surface 34 of the light guide 3, the distance D1 from the light incident end surface is close to the light incident end surface 31. In the region of the width W1 with '), as described above with reference to FIGS. 28 and 29, the ink dots 36A that are independent or partially continuous with each other are formed by the inkjet method.

Next, as described with reference to Figs. 28 and 29, the leveling of the ink dots is performed. Thereby, as shown in FIG. 45, the ink layer which adjoins adjacent ink dots and is continuous over the whole area | region of the width W1 by the distance D1 from the light-incidence end surface 31 is located. Consisting of 36B. The area of the width W1 includes all of the areas of the width W1 ', and is slightly larger than the width W1' by leveling.

Next, the first light absorption band 36 is formed by curing the ink layer 36B.

As mentioned above, what was said about the 1st absorption band 36 is also suitable also about the 2nd light absorption band 136. FIG. That is, as shown in FIG. 44, the inkjet method is similarly applied to the area | region which deviated from the area | region of the width W1 'in the area | region within the said substantially flat surface area | region 137 of the back surface 34 of the light guide 3. The ink dots 136A are formed independently of one another or in part by continuous. All of these ink dots may be completely independent as shown, but some of them may be partially overlapping and continuous. Next, the ink dot is leveled similarly. As a result, as shown in FIG. 45, the adjacent ones of the ink dots are joined to form a continuous ink layer 136B over the entire region deviating from the region of the width W1. Next, the second light absorption band 136 is formed by curing the ink layer 136B. As described above, by controlling the bonding state of the ink dots in the ink layer 136B as desired by the leveling time, the surface state of the second light absorption band 136, that is, the degree of irregularities can be controlled. Proper irregularities are formed on the surface of the second light absorption band 136, whereby unnecessary light can be made less noticeable. That is, as described above, when a part of the light generated from the primary light source 1 is reflected from the light source reflector 22 and reaches the second light absorption band 136 without reaching the light incident end face 31, the excitation Most of it is absorbed. At this time, the remaining light is reflected on the light guide surface 34 side, but the reflected light is diffusely reflected by the unevenness of the surface of the second light absorption band 136, which makes it inconspicuous.

Further, by forming the first and second light absorption bands 36 and 136 as described above in parallel, the time for formation is shortened.

46, the further another example of the manufacturing method of the above light guide is demonstrated. This figure corresponds to the above-mentioned FIG. 30, and the same code | symbol is attached | subjected to the member or part which has a function similar to FIG.

In this example, first, the light guide material 3 'as shown in Fig. 46A is prepared. Next, as shown in FIG. 46 (b), the cutting process is performed on the light incident end surface correspondence portion 31 'to form the light incident end surface 31. By this cutting process, the protrusion part 39 which protrudes toward the back surface 34 is formed in the boundary between the light incident end surface 31 and the back surface 34. As shown in FIG. The protruding portion 39 extends along the boundary line between the light incident end face 31 and the rear face 34, that is, along the light incident end face 31. The protrusion 39 can be formed by cutting as described above, but may be formed by molding at the time of injection molding.

Next, as shown in FIG. 46 (c), ink dots 36A and 136A are formed in required areas of the back surface 34. As shown in FIG. This ink dot is formed as in FIG. 44 described above. Next, the ink dots are leveled, and ink layers 36B and 136B are formed in required areas of the light exit surface 33 as shown in Fig. 46D. These ink layers are formed as in FIG. 45 above, but here, so that the side edges close to the light incident end face 31 of the ink layer 36B formed by leveling reach the protrusions 39, The position of the ink dot formation area is set. That is, the area | region in which the ink dot 36A shown in FIG. 46 (c) is formed deviates only a little from the light incident end surface 31. FIG. Thereby, the ink flowing at the time of leveling of the ink dot prevents the projection 39 from moving to the light incident end surface 31.

Finally, the first and second light absorption bands 36 and 136 are formed by curing the ink layers 36B and 136B.

According to the above method, as described with reference to FIG. 30, it is easy to form the first light absorption band 36 extremely close to the light incident end face 31 without following the light incident end face 31. According to the first absorption band 36, the decrease in the amount of light incident on the light guide 3 from the light incident end face 31 can be suppressed. Also in this method, what was demonstrated about said FIG. 34 is suitable.

In the present invention, as described above with reference to FIG. 31, the first and second light absorption bands 36 and 136 can be used containing light diffusing or light absorbing fine particles.

It is a typical partial perspective view which shows one Embodiment of the light guide for surface light source devices which concerns on this invention. In this figure, the same code | symbol is attached | subjected to the member or part which has a function similar to the said FIGS. 19-47.

In the present embodiment, a substantially flat surface region 137a having a predetermined width extending along the light incident end surface 31 is provided near the light incident end surface 31 on the back surface 34 of the light guide 3. Formed. The area | region of the back surface 34 other than this substantially flat surface area | region 137a becomes the prism column formation surface area | region 139. As shown in FIG. The substantially flat surface area 137a may be a smooth surface or roughened like the above substantially flat surface area 137. However, unlike the substantially flat surface area 137, the substantially flat surface area 137a is at the same height position (Z-direction position) as the ridge line of the prism row. The width of the substantially flat surface area 137a is about the same as that of the approximately flat surface area 137. In this substantially flat surface region 137a, a light absorption band 36 extending along the light incident end face 31 is formed. A transition region having a function similar to that described in the above embodiment may be provided between the substantially flat surface region 137a and the prism row forming surface region 139.

In this embodiment, there exists an advantage that manufacture of the metal mold | die for light guide manufacture becomes easy in the Z direction position substantially flat surface area | region 137a is substantially the same as the ridge line of a prism row. Such a substantially flat surface area 137a can be used in place of the approximately flat surface area 137 in all of the above embodiments.

In addition, in this embodiment, also in the light output surface 33 used as the mat surface which comprises a directional light output mechanism, the light absorption band 236 extended along the light incident end surface 31 is formed. The light absorption band 236 is configured such that the width (X direction dimension), the positional relationship with respect to the light incident end face 31, and the like are the same as those described with respect to the light absorption band 36, and is the same as the light absorption band 36. Has the function.

According to this embodiment, in addition to the light absorption band 36, by providing the light absorption band 236, the generation | occurrence | production of the bright line in the vicinity of a light incident cross section can be prevented more effectively. In this case, however, the visible light transmittance of the light absorption band 236 is preferably lower than the visible light transmittance of the light absorption band 36.

Similarly, in the embodiment of FIGS. 37 to 46, the light absorption band 236 extending along the light incident end surface 31 can be formed on the light exit surface 33. In addition, as shown in FIG. 49, in the embodiment of FIGS. 37-46, in addition to the light absorption band 236 to the light output surface 33, the width (X direction dimension) and the light incident cross section 31 are shown. ), The second light absorption band 336 may be formed such that the positional relationship and the like with respect to) are equivalent to those described with respect to the second light absorption band 136. Here, the operation of the light absorption band 236 and the second light absorption band 336 will be described (the operation of the light absorption band 36 and the second light absorption band 136 is as described above).

Of the light introduced from the light incident end face 31 into the light guide 3, the light L1 ′ reaching the light absorption band 236 is absorbed by the light absorption band. The rest of the light is reflected by the light exit surface 33 and becomes light L2 'which travels in the light guide. This light L2 'exits from the back surface 34, is reflected by the light reflecting element 5, reenters into the light guide body, and exits from the light exit surface 33. In the present invention, the light L2 'can be made sufficiently weaker than the light L1' by the light absorption in the first light absorption band 36, so that the bright line generation is further suppressed.

In addition, among the light introduced into the light guide 3 from the light incident end face 31, part of the light L3 'reaching the second light absorption band 336 is absorbed by the second light absorption band. The remainder is reflected by the light exit surface 33 to become light L4 'which travels in the light guide. The light L4 'is emitted from the back surface 34, reflected by the light reflecting element 5, reincident into the light guide body, and is emitted from the light exit surface 33. In the present invention, the light L4 'can be made weaker than the light L3' by the light absorption in the second light absorption band 336, so that the intensity difference with the light L2 'is reduced. Therefore, there is no big difference in luminance in the region where the light L2 'first emits on the light exit surface and the region where the light L4' near the first exits on the light exit surface (i.e., the reduction in the brightness contrast). Contributes to).

In particular, the light L5 ′ introduced into the light guide 3 from the edge portion that forms the boundary between the light guide back surface 34 and the light incident end face 31 and reaches the second light absorption band 336 is applied to the light guide. 2 A part thereof is absorbed by the light absorption band. The rest of the light is reflected by the light exit surface 33 to become light L6 'that travels in the light guide. This light L6 'exits from the back surface 34, is reflected by the light reflecting element 5, reenters into the light guide body, and exits from the light exit surface 33. In the present invention, the light L6 'can be made weaker than the light L5' by the light absorption in the second light absorption band 336, so that the intensity difference with the light L2 'is reduced. Therefore, there is no big difference in luminance in the region where the light L2 'first emits from the light exit surface and the region where the light L6' near the first exits from the light exit plane (i.e., the reduction in the brightness contrast). Contributes to).

In addition, some of the light generated from the primary light source 1 is reflected by the light source reflector 2 and reaches the light absorption band 236 and the second light absorption band 336 without reaching the light incident end face 31. The placenta is absorbed here. For this reason, the bright line generation is further suppressed.

The formation of the light absorption band 236 and the second light absorption band 336 on the light exit surface 33 may be further used in the embodiments of FIGS. 19 to 36.

In the above-mentioned embodiment, although the prism row forming surface is provided in the back surface 34 of the light guide 3, and the light output mechanism is provided in the light output surface 33, on the contrary, the back surface 34 of the light guide 3 is provided. ), A light emitting mechanism, for example, may be provided with a rough surface, and a prism heat forming surface may be provided on the light emitting surface 33. That is, in the embodiment of Figs. 19 to 36, the embodiment of Figs. 37 to 46, the embodiment of Fig. 48, and the other embodiments, the light absorption bands 36 and 236 and the second light absorption band are shown. The arrangement of the light guide 3 can be reversed upside down with the 136, 336 or the arrangement of the light absorbing band 36, 236 and the second light absorbing band 136, 336 can be maintained. It may be reversed up and down, and the prism heat forming surface may be a light emitting surface, and the rough surface may be disposed on the back surface side. Even in such an arrangement, the effect as described in the above embodiment can be obtained based on the action of the light absorption band and the second light absorption band.

In this case, even in a case where the light absorbing band 36 and the second light absorbing band 136 are not formed on the light emitting surface or the back surface on which the prism rows are formed, the substantially flat surface regions 137 and 137a are formed. By forming, the bright line generation is further suppressed. It is easy to leave a gap between the edge of the light source reflector 2 and the prism row forming surface of the light guide when substantially flat surface areas 137 and 137a are not formed, and from this prism from the primary light source 1 via this gap. Although light incidence to the column formation surface may cause a bright line generation, when substantially flat surface areas 137 and 137a are formed, the edge of the light source reflector 2 and the prism row of the light guide body It is considered that it is difficult to provide a gap between the formation surface, and therefore, light incidence from the primary light source 1 to the prism column formation surface is unlikely to occur, and thus, it is considered that the cause of the bright line is reduced by one.

50 is an exploded perspective view showing an embodiment of the surface light source device according to the present invention. As shown in Fig. 50, the surface light source device of the present embodiment includes a plurality of LEDs 102 as point-shaped primary light sources and the light generated from the LEDs incident and guided from a light incident end face to emit light. And a light guide element 104 in the form of a square plate in the XY plane to be emitted from the light, and a light deflecting element 106 and a light reflecting element 108 disposed adjacent to the light guide. The light guide 104 has four top and bottom main surfaces, and four edges which arrange the outer periphery of the main surface.

The LED 102 is adjacent to one of a pair of edges approximately parallel to each other of the light guide 104 (adjacent edge in the left front side of FIG. 50) and is also suitable for each other in the center and both sides thereof in the Y direction. Is being deployed. In the present invention, the point light sources such as LEDs, which are primary light sources, are preferably as few as possible from the viewpoint of low power consumption, but can be arranged at equal intervals or close to each other by the size of the light guide 104.

At the incidence edge of the light guide 104, a light incident end face 141 corresponding to the position where the LED 102 is arranged is formed. The light incident end surface 141 formed in the light guide 104 may be formed by cutting the incidence edge in a concave shape so as to have a lower back surface shape or the like. It is preferable that the LED light emitting surface and the light incident cross section have a shape (including a case where both surfaces are flat) fitting each other in the uneven region. In addition, in order to enlarge the light in the XY plane, the light incident end face 141 is preferably roughened as described with respect to the light guide light incident end face 31 in the embodiment other than FIG. 1.

As for the light guide 104, one main surface (upper surface in a figure) is the light output surface 143. As shown in FIG. The light exit surface 143 is a directional light exit mechanism that emits light guided in the light guide body 104 in a direction inclined with respect to the light exit surface 143 (that is, in a direction inclined with respect to the XY plane). Equipped with. The directional light emitting mechanism is, for example, a rough surface (mat surface). The directional light output mechanism emits light having directivity in the XZ plane distribution including both the normal direction (Z direction) of the light exit surface 143 and the X direction perpendicular to the incidence edge. The angle which the direction of the peak of this emission light distribution forms with the light emission surface 143 is 10 degrees-40 degrees, for example, and the half value width of an emission light distribution is 10 degrees-40 degrees, for example.

As for the light guide 104, the other main surface (lower surface in the figure; rear surface) is the lens row formation surface 144 serving as the uneven structure row formation surface. The lens column forming surface 144 is formed in the direction of the directivity of the light generated from the LED 102 and incident on the light guide body 104 (except the region near the incidence edge) (the direction of the maximum intensity in the light intensity distribution). It has lens rows as a plurality of rows of uneven structures extending in a substantially along direction and arranged substantially parallel to each other. For example, when the direction of the directivity of the light incident on the light guide 104 is approximately the X direction, as shown in FIG. 51, the direction of the lens row 144a can be the X direction (FIG. 51). Is indicated by the ridge line of each lens row 144a]. In the present invention, the direction of the lens rows 144a may be shifted from the direction of the directivity of the light incident on the light guide 102 as long as the direction does not significantly impair the effect of enlarging the light. It is regarded as a direction almost along the direction of the directivity of the light incident on 104. In this case, the direction of the lens array 144a is preferably within a range of 20 ° with respect to the direction of the directivity of light incident on the light guide, more preferably within a range of 10 °. By forming the lens rows in this direction, the light incident on the light guide can be enlarged in the XY plane, and dark areas are less likely to occur.

Moreover, in this invention, the strip | belt-shaped flat part 144b extended along the said light incident cross section is formed in the area | region near the light incident cross section of the lens column formation surface 144, It is characterized by the above-mentioned. The flat part 144b is formed in at least a part of the area from the area in contact with the light incident end surface of the lens row forming surface 144 to the effective light emission area. By forming such a flat portion 144b, the light from the primary light source can be mixed between the effective light emitting regions, thereby suppressing the bright muscle shape irregularities in the oblique direction as shown in FIG. This flat part may be a mirror surface and may be roughened.

The light deflecting element 106 is disposed on the light exit surface 143 of the light guide 104. The two main surfaces of the light deflecting element 106 are each positioned parallel to the XY plane as a whole. One of the two main surfaces (the main surface located on the light exit end face 143 side of the light guide) is a light incident surface 161, and the other is a light exit surface 162. The light exit surface 162 is a flat surface parallel to the light exit surface 143 of the light guide 104. The light incident surface 161 is a lens row forming surface in which a plurality of lens rows 161a are arranged in parallel with each other. The lens rows 161a of the light incident surface 161 extend in a direction substantially perpendicular to the direction of the directivity of the light from the LEDs 102 incident on the light guide 104, and are formed in parallel with each other. In the present embodiment, the lens rows 161a extend in the Y direction.

52 shows the shape of light deflection by the light deflection element 106. This figure shows the advancing direction of the peak outgoing light (light corresponding to the peak of the outgoing light distribution) from the light guide 104 in the XZ plane. Light inclined from the light exit surface 143 of the light guide 104 is incident on the first surface of the lens row 161a, totally reflected by the second surface, and almost exits in the direction of the normal of the light exit surface 162. . In addition, within the YZ plane, due to the action of the lens columns 144a as described above, the luminance in the direction of the normal line of the light exit surface 162 can be sufficiently improved in a wide range.

Fig. 53 is a perspective schematic view of the light exit surface side of the light guide of the present invention; 102 'in the figure shows the installation position of LED102. On the light exit surface 143 of the light guide 104, a light guide in front of each LED installation position 102 ′ near the light incident end surface 141, that is, in the plane along the light exit surface 143. On the straight line extending generally along the direction (normally X direction) of the light incident from the LED 102, the high light-diffusion region 431 extending along this straight line is formed. This high light diffusion region 431 is a region formed so as to have higher light diffusivity than its surroundings, and has a fine concavo-convex surface, a concave-convex structure such as a dot or an abstract volcanic projection, and the average inclination angle? It is preferable to set so that it may become .1-1 degree large. If the value of the average inclination angle θa is less than 0.1 °, there is a tendency that the suppressing effect of dark part generation in front of the LED 102 cannot be sufficiently exhibited. On the contrary, if the average inclination angle θa is over 1 °, the high light diffusion region 431 becomes excessively bright, resulting in uneven luminance. Tends to result in the occurrence of. The difference between the high light diffusion region 431 and the average inclination angle θa around it is more preferably in the range of 0.3 to 0.7 °, still more preferably in the range of 0.2 to 0.4 °. The high light diffusion region 431 is preferably formed such that the average inclination angle θa is gradually changed at least in the boundary region with the surroundings in order to avoid deterioration of quality due to a sudden change in the light diffusivity with the surroundings.

The high light diffusion region 431 is formed in a vertical shape such as a rectangle or a triangle so as to extend generally along a straight line extending generally in the direction of the directionality of incident light, but deterioration of quality due to a sudden change in light diffusivity with the surroundings. In order to avoid this, it is preferable that the corners are rounded or elliptical. Although the width and length of the high light diffusion region 431 can be appropriately set in accordance with the generated dark portions, in order to effectively suppress the dark portion generation in front of the LED 102 within a range in which the high light diffusion region is not too bright, It is preferable that the aspect ratio is in the range of 1.1 to 7, the width is 0.5 to 5 mm, and the length is about 0.55 to 35 mm, and more preferably the aspect ratio is the range of 3 to 5, and the width is 1.5 to 4.5 mm and the length is It is the range of 5-15 mm.

The position at which the high light diffusion region 431 is formed can also be appropriately set in accordance with the generated dark portion. However, in order to effectively suppress the dark portion generation in front of the LED 2 in a range in which the high light diffusion region is not too bright, It is preferable to form the end portion at a position of 0.5 to 7 mm from the incident end face 41, and to make the end portion of the high light diffusion region 431 be outside the effective light emitting region.

In the present invention, it is preferable that portions other than the high light diffusion region 431 of the light exit surface 143 also form light exit mechanisms such as rough surfaces and uneven structure surfaces. As the concave-convex structure, a plurality of lens rows such as prism rows, lenticular lens rows, or V-shaped grooves are directions (Y direction) that are substantially orthogonal to the direction of directivity of the light from the LEDs 102 incident on the light guide 104. Or it extends in the substantially parallel direction (X direction), and formed in parallel with each other, etc. are mentioned. In addition, the lens row in this case is not limited to a linear shape, but may be a curved one so as to surround the LED 102.

As for the rough surface and uneven structure surface as such a light output mechanism, the average inclination angle (theta) a by ISO4287 / 1-1984 measured in the direction of the directivity of the light which entered the light guide should be in the range of 0.2-20 degrees. It is preferable at the point which aims at equalizing the brightness in (143). Average inclination angle (theta) a becomes like this. More preferably, it is the range of 0.3-10 degrees, Especially preferably, it is the range of 0.5-5 degrees.

In the case of using a lens row extending in the Y direction as the light output mechanism, the lens row used for this purpose is, for example, a prism row, and the arrangement pitch is preferably 10 to 100 탆, more preferably 10 to 80. It is the range of 20 micrometers, More preferably, it is 20-60 micrometers, Apex angle is preferably 140 degrees-179.6 degrees, More preferably, it is the range of 156 degrees-179.4 degrees, Especially preferably, it is the range of 164 degrees-179 degrees.

The average inclination angle θa of the rough surface or lens row as the light output mechanism formed on the light guide 104 is as described in the embodiment other than FIG. 1 described above, and can be obtained according to ISO4287 / 1-1984.

As a light emitting mechanism of the light guide, a material having a refractive index different from the main component of the light guide may be present in the light guide. As a substance of such refractive index, a fine particle may be dispersed in the light guide, and a phase of refractive index may be provided on the surface or inside of the light guide. The refractive index difference with the main component of the light guide is preferably 0.002 or more and 0.3 or less, more preferably 0.005 or more and 0.2 or less, and even more preferably 0.01 or more and 0.1 or less. As a shape of the substance of phase refractive index, disperse | distributing a thing of particulate form is especially preferable from the point of ease of manufacture. As an example of microparticles | fine-particles, a silicone type, a styrene type, its copolymer, an acryl type, its copolymer, inorganic fine particles, etc. are mentioned. As concentration of microparticles | fine-particles, 0.01 mass% or more and 10 mass% or less are preferable, 0.1 mass% or more and 5 mass% or less are more preferable, 0.2 mass% or more and 3 mass% or less are more preferable.

This light output mechanism is provided so that light diffusivity becomes nonuniform in the light exit surface 143 of the light guide body 104, and suppresses the brightness unevenness in the light exit surface 143, or distributes the brightness. Can also be optimized. In the state where the average inclination angle of the light output mechanism of the light guide is uniform throughout the effective light emitting region, the luminance decrease occurs when the light deflection element, the light reflection element, and the primary light source are measured to measure the normal luminance. In this case, the luminance unevenness can be reduced by making it larger and setting it smaller in the region where the luminance becomes higher.

In the surface light source device such as the present invention, in particular, a small surface light source device, the brightness of the center portion is preferably high and distributed so as to gradually decrease as it goes around, and the average inclination angle is centered on the center of the light exit surface 143. It is preferable to form a large area | region and to make another part into the area | region with small average inclination angle. In the embodiment illustrated in FIG. 53, a region 432 having a large average inclination angle including the center portion of the light exit surface 143, a region 433 having a slightly larger average inclination angle around the periphery thereof, and located near the light incident cross section and having high light Three regions of the region 434 having a small average inclination angle including the diffusion region 431 are formed. In this case, the average inclination angle θa of the region 434 having a small average inclination angle is preferably in the range of 0.2 to 2 degrees, more preferably in the range of 0.5 to 1.5 degrees. Moreover, it is preferable to make the average inclination-angle (theta) a of the area 433 slightly larger in average inclination-angle in the range of 1-10 degrees, More preferably, it is the range of 1.5-5 degrees. Moreover, it is preferable to make the average inclination-angle (theta) a of the area | region 432 with a large average inclination-angle into 1.5 to 20 degree, More preferably, it is the range of 2 to 10 degree. Each area is preferably formed such that the average inclination angle θa gradually changes in at least each boundary area in order to avoid deterioration of quality due to a sudden change in light diffusivity between adjacent areas.

In the present invention, in order to suppress the appearance of luminance unevenness, it is preferable to optimize the cross-sectional shape of the uneven structure rows such as the lens rows 144a formed on the light guide 104. As the optimization of this cross-sectional shape, it is based on the inclination angle (microinclination angle) in the micro area | region required for specification of the uneven | corrugated structure train | elongation, such as lens column cross-sectional shape demonstrated below, and the existence ratio (distribution frequency) of the angular component based on it. do.

As a cross section for calculating the minute inclination angle and the distribution frequency which specifically determine the cross-sectional shape of the uneven structure column such as the lens row 144a, a cross section substantially perpendicular to the direction in which the uneven structure column such as the lens row extends is taken (Fig. 54). See (a) of]. When the uneven structure rows such as the lens rows 144a are not completely parallel to each other, the cross section of the curved shape is taken so as to be orthogonal to the direction in which the uneven structure rows such as the lens rows are extended (see FIG. 54 (b)). ].

From the lens row cross-sectional shape, as shown in FIG. 55 (a), the shape for five cycles of the cross-sectional repeating structure is extracted. The cross-sectional shape is divided into 500 minute regions in 500 equal parts (100 equal parts for each repeating unit) along the shape line. In addition, the extraction of the cross-sectional shape need not be limited to 5 cycles, and the number of divisions need not be limited to 500, and these can be obtained as long as an appropriate inclination angle or distribution frequency representing the entire cross-sectional shape can be obtained. It can be changed appropriately.

As shown in FIG. 55 (b), in each micro area, the tangent line (for example, it is a tangent line at the center position of the micro area, and approximately shown in FIG. 55 (b)). It is also possible to represent it from the line segment which connects both ends as follows. The same is below) and the uneven | corrugated structure formation surface, such as lens row | mold formation surface 144 (here, it refers to the plane which disregarded uneven structure heat | emission, such as lens row. The absolute value of this angle (inclined angle) is obtained, and the frequency distribution of the absolute value of the inclination angle with respect to the entire microarea (the ratio of the number of the microregions with the angle of inclination to the total number of microareas) is obtained by an angle of 1 °. Each angle (that is, the angle is represented by α °, and the angle range of α °-0.5 ° or more or less than α ° + 0.5 ° is represented by angle (°)). An example of calculation of this frequency distribution is shown in FIG.

The obtained frequency distribution WHEREIN: The ratio with respect to the number of all the micro area | regions of the number of the micro area | regions which take the angle of a certain range is calculated | required, and this is called the existence ratio of the angular component of this angle range. The shape of the uneven structure rows such as the lens rows is particularly determined by this existence ratio. For example, in FIG. 56, when the ratio with respect to the total number of micro area | regions of the number of micro area | regions of the angle range of 20-50 degree was 35%, the existence ratio of 20-50 degree of angular components is assumed to be 35%.

As shown in FIG. 57, when the shape of each repeating unit of the cross-sectional repeating structure is asymmetrical, the shape of five cycles of the cross-sectional repeating structure is extracted, and only the left portion of each repeating unit is extracted. Are divided into 50 equal parts according to the shape lines, respectively, and divided into 250 minute areas in total. Similarly, with respect to only the right part of each repeating unit, 50 equal parts along the shape lines are respectively divided into 250 minute areas in total. Divide. And in each micro area | region of the left part, the absolute value of the angle (inclined angle) which forms the tangent line and the uneven structure row formation surface, such as the lens row formation surface 44, is calculated | required, and the inclination-angle absolute value with respect to all the micro area | regions is obtained. The frequency distribution of is calculated for each angle of 1 °. Similarly, the frequency distribution of the absolute value of the inclination angle with respect to the entire minute region is also calculated for each angle of 1 ° with respect to the right portion. In addition, the extraction of the cross-sectional shape need not be limited to five cycles, and the number of divisions need not be limited to the above-described ones, and these are minute inclinations representing the entire cross-sectional shape with respect to the respective left and right portions. As long as an appropriate thing can be obtained as an angle or distribution frequency, it can change suitably.

In addition, as shown in FIG. 58, although there exists the case of the irregular shape which is not necessarily recognized as repetition of a unit shape in cross-sectional shape in the uneven structure row, in that case, it measured according to the shape line of a cross-sectional shape. The 500-micrometer-long length is extracted, 50O is divided equally along the shape line, and the frequency distribution is computed as above with respect to each micro area | region of 1 micrometer of length obtained by this. In addition, the extraction of the cross-sectional shape need not be limited to 500 µm in length, and the number of divisions need not be limited to 500, and these can obtain an appropriate one as a small inclination angle or distribution frequency representing the entire cross-sectional shape. As long as it is possible, it can change suitably.

In addition, in the present invention, in the case of a cross-sectional shape in which substantially the same unit shape repeats regularly (that is, when the uneven structure row is a lens row), the valleys formed in the boundary between adjacent repeating units (the most in the cross-sectional shape) The shape of the region near the low position greatly influences the optical performance. There, the lens valley part inclination angle is used as an evaluation item. The measurement is as follows. As described above, the shape of, for example, five cycles of the cross-sectional repeating structure is extracted. The cross-sectional shape is divided into, for example, about 500 equal parts (100 equal parts for each repeating unit) according to the shape line, and is divided into, for example, 500 minute regions. In the five lens valleys formed at the boundary portions of the repeating units, the average value of the inclination angles of the six small regions on the left and right sides is obtained from the boundary of the repeating units. And when the shape of each repeating unit is symmetrical, the average of the average value of 10 calculated | required as mentioned above is called, and it is called the valley part inclination angle of the said lens row. In addition, when the shape of each repeating unit is asymmetrical left and right, the average of five average values is averaged with respect to each of the left and right sides calculated | required as mentioned above, and it is called left valley inclination angle and right valley inclination angle of the said lens row.

By the way, as described above, the luminance unevenness of the dark portion shown in Fig. 73 is easily visible in the effective light emitting area when the primary light source interval is wide and the distance from the light incident end face is small. In order to reduce such luminance unevenness, the light incident on the light guide is sufficiently enlarged in the XY plane in the vicinity of the primary light source, that is, in the vicinity of the light incident cross section, and the light is passed through the light deflecting element 106 in a large area so that the light can be observed. It is necessary to do Therefore, in this invention, the lens column 144a of at least the vicinity of a primary light source, ie, the vicinity of a light incident cross section, is made into the shape which is excellent in the effect which enlarges light. As described above, the light incident on the light guide travels in the inclined direction with respect to the direction of the directivity of the light by the reflection in the lens column 144a in the XY plane, and the light traveling in the inclined direction is the lens row 144a. The reflection in the direction returns to the direction of the directivity of the incident light. As a result, the light incident on the light guide is widened in the XY plane, and further propagates in a direction substantially perpendicular to the lens column 161a of the light deflecting element 106. For this reason, when it passes through an optical deflection element and observes from the light emission surface normal line direction, light looks wide.

In order to enhance the effect of enlarging such light, a shape in which the existence ratio of the angular component of 20 to 50 ° is more than or equal to a predetermined value in the cross-sectional shape of the uneven structure rows such as the lens rows 144a is preferable. In order to heighten the effect | action which expands light more, the shape whose presence ratio of the angle component of 25-50 degrees is more than a fixed value is preferable, or the shape whose presence ratio of the angle component of 30-50 degrees is more than a fixed value is preferable, Or the shape whose presence ratio of 35-50 degree angle component is more than a fixed value is preferable, or the shape whose presence rate of 40-50 degree angle component is more than a fixed value is preferable. In order to heighten this effect, the more the ratio of the said angular component exists, the more preferable.

Here, the cross-sectional shape of the uneven structure rows such as the lens rows 144a means the averaged extracted at the time of calculating the parameter. Therefore, when the cross-sectional shape is an irregular shape as described above, each of the uneven structure rows It means not being obsessed with shape, but averaged. In addition, when the shape of each repeating unit of the repeating structure having a cross-sectional shape is asymmetrical as described above, it is necessary to correspond to the above in each of the left part and the right part. Hereinafter, although the uneven structure row is a lens row and the shape of each repeating unit of the repeating structure of a cross-sectional shape is a left-right symmetry, the other case is also the same.

In order to increase the effect of enlarging the light, the angle component of 20 to 50 ° represented by the absolute value of the inclination angle in the cross-sectional shape of the lens column 144a at least in the vicinity of the primary light source (near the light incident cross section). It is preferable that the ratio of is made 10% or more, More preferably, it is 20% or more, More preferably, it is 30% or more. In order to increase the effect of enlarging the light further, the existence ratio of the angle component of 25 ° or more and 50 ° or less in the cross-sectional shape of the lens row 144a is at least 10 in the vicinity of the primary light source (near the light incident end face). It is preferable to set it as% or more, More preferably, it is 20% or more, More preferably, it is 30% or more.

In order to increase the effect of enlarging the light further, the existence ratio of the angle component of 25 to 50 ° in the cross-sectional shape of the lens array 144a is at least 20% at least in the vicinity of the primary light source (near the light incident cross section). It is preferable to set it as it, More preferably, it is 30% or more, More preferably, 40% or more, or the ratio of 30-50 degrees of angular components in the cross-sectional shape of the lens row 44a shall be 5% or more. It is preferable, More preferably, it is 10% or more, More preferably, it is 15% or more.

In order to further enhance the effect of expanding the light, the ratio of the presence of an angle component of 30 to 50 ° in the cross-sectional shape of the lens array 144a is at least 10% in the vicinity of the primary light source (near the light incident end face). It is preferable to set it as it, More preferably, it is 20% or more, More preferably, it is 30% or more, or the ratio of 35-50 degrees of angular components in the cross-sectional shape of the lens row 44a shall be 8% or more. It is preferable that it is 10% or more, More preferably, it is 20% or more, or it is preferable that the existence ratio of the 40-50 degree angle component in the cross-sectional shape of the lens row 44a is 2% or more. More preferably, it is 3% or more, More preferably, it is 5% or more.

In order to increase the luminance measured in the light exit plane normal direction, the light in the direction inclined with respect to the direction of directivity in the plane parallel to the light exit plane of the light incident on the light guide has a greater effect in the direction of the directivity of the light. This is preferable, and for this purpose, it is preferable that the lens row 144a is provided so as to have a function of converging in the direction in which the lens row 144a extends while changing the traveling direction of light by reflection.

In order to suppress the luminance unevenness of the bright-shaped inclination which occurs in order to enlarge the light by having anisotropy in a specific direction in the lens row 144a as shown in FIG. 74, the light is not concentrated at a specific angle. It is preferable to make the cross-sectional shape of the lens row 144a into a curved shape. Specifically, at least in the vicinity of the primary light source, a certain angle is set to α ° in the cross-sectional shape of the lens column 144a, and the abundance ratio of the angle component of α ° to α ° + 10 ° is set to α ° = When calculated | required about the whole angle within the range of 0-80 degree, it is preferable to make it the maximum value become 60% or less, Preferably it is 50% or less, More preferably, it is 40% or less. If this maximum value is too high, the cross-sectional shape of the lens row 144a becomes linear, and the anisotropy in a specific direction becomes easy to enlarge the light. Therefore, the luminance unevenness of the bright shape having a bright inclination direction as shown in FIG. It is easy to occur.

On the other hand, if the maximum value of the abundance ratio of the angle components of α ° to α ° + 10 ° is to be made small, the cross-sectional shape of the lens rows is forced to have many angle components. In the present invention, as described later, when the angular component of 35 ° or less is too large, light traveling in the direction of the direction of incident light is relatively increased, and the phenomenon that the front of the primary light source is brightened. Moreover, an angular component larger than 50 ° also has a small effect of enlarging light. For this reason, it is preferable that the cross-sectional shape of a lens row distributes the most micro area | region in the range of 60 degrees or less of angle components, Preferably it is 50 degrees or less. Therefore, the maximum value of the abundance ratio of the angle component of α ° to α ° + 10 ° is preferably at least 15%, preferably at least 20%.

For the above reasons, 60% or less is preferable, as for the existence ratio of the above-mentioned 40-50 degree angle component, 50% or less is more preferable, 40% or less is still more preferable. Moreover, 90% or less is preferable, as for the existence ratio of the above-mentioned 35-50 degree angle component, 75% or less is more preferable, and 60% or less is still more preferable. Moreover, 80% or less of the existence ratio of the above-mentioned 30-50 degree angle component is preferable.

Next, the light incident end surface 141 is demonstrated. When the light incident end surface is roughened, a lot of light in the oblique direction is incident on the direction of the directivity of the light in a plane parallel to the light exit surface 143 of the light incident on the light guide. As a result, the light is enlarged in the XY plane, and the dark portion as shown in FIG. 73 becomes small. However, when the magnification of the light becomes large, the light traveling in the oblique direction tends to be emitted by the reflection in the lens row 144a, so that the bright muscle portion as shown in FIG. Lose.

For this reason, in this invention, in order to prevent this luminance unevenness generate | occur | producing in an effective light emission area | region, light incident on at least one part area | region between the area | region which touches the light incident end surface 141 to the effective light emission area | region. A strip-shaped flat portion 144b extending along the cross section 141 is formed. Although light from the primary light source has a property that only light having a certain angular component is easily emitted by reflection in the lens row 144a, bright near-shaped luminance unevenness as shown in FIG. 76 occurs, but the light incident cross section 141 ), A band-like flat portion 144b extending along the light incident cross section exists in at least a portion of the region from the region in contact with the region to the effective light emitting region, so that light from neighboring primary light sources is flat. Even when light reaches the region where the lens rows 144a are formed by mixing negatively, the near-brightness luminance unevenness is suppressed by this mixing effect.

In addition, the specific shape of the lens array 144a has an existence ratio of 30 to 50 ° of an angular component of 40% or less, preferably 30% or less, and also 5% or more, preferably 10% or more, more preferably 15 % Or more is preferable. Alternatively, the proportion of the angular component of 35 to 50 degrees or less is preferably 30% or less, preferably 20% or less, further 2% or more, preferably 8% or more, and more preferably 13% or more. Alternatively, the specific shape of the lens row 144a has a valley inclination angle of 30 ° or less, preferably 25 ° or less, more preferably 20 ° or less, and also 5 ° or more, preferably 8 ° or more, more preferably 10 ° or more is preferred. If these angular component presence ratios and valley inclination angles are too high, the effect of preventing luminance unevenness as shown in FIG. 76 tends to be lowered. If too small, light that has been enlarged in the region near the primary light source can be compared with the prism rows of the prism sheet. It cannot be reflected in the vertical direction, and the prism sheet tends to reduce the component of light standing up in the normal direction of the light exit surface, and as a result, the luminance in the normal direction tends to decrease.

As a method of partially changing the shape of the lens row forming surface, there is a method of roughening. By roughening at least a part of the surface of the lens row in various ways, it is possible to change at least a part of the lens row shape easily and inexpensively. It is also possible to continuously change the degree of this change and gradually change the lens column shape by position. By roughening the lens array 144a, luminance unevenness as shown in FIG. 73 can also be eliminated.

In order to reduce the luminance unevenness due to the superposition of the light generated from the plurality of primary light sources as shown in FIG. 73, it is preferable to appropriately make the relationship between the luminance distribution of the light generated from each primary light source and the distance between the light sources. Specifically, in the state where the light deflecting element 106 and the light reflecting element 108 are provided, when only one of the plurality of primary light sources 102 provided adjacent to the edge of the light guide 104 is lit, FIG. 59. As shown in Fig. 2, the normal luminance is measured at intervals of 1 mm along the longitudinal direction (y direction) in the region S of a width of 0.5 mm of 3 to 3.5 mm from the edge of the light incident cross section side of the effective light emission region. When the relationship between the measurement position y [mm] and the luminance is plotted, it is preferable that the ratio of the half-width full-width distance to the distance between the primary light sources is in the range of 0.8 to 1.2 times, and preferably about the same. Examples of graphs in which the relationship between the measurement position y [mm] and the luminance are plotted in FIGS. 60A and 60B are shown. FIG. 60A shows a case where this ratio is larger than 1.2 times, and FIG. 60B shows a case where this ratio is smaller than 0.8 times. When this ratio is too big | large, as shown to Fig.61 (a), the superposition of the distribution of the light from the adjacent primary light source 2 will become large, and this part of superposition will become especially bright and it will become easy to produce a contrast shape. If the ratio is too small, as shown in Fig. 61 (b), the enlargement of the distribution of the light from the primary light source 2 is insufficient, and the front portion of the primary light source is particularly bright, so that the middle of the adjacent primary light source is The area corresponding to the position is relatively dark, so that the contrast is likely to occur.

As a preferable cross-sectional shape of the lens row 144a, a part or all of the cross-sectional shape line is formed by a convex curve outward as shown in Fig. 62, a shape made by a concave curve outward as shown in Fig. 63, and outward as shown in Fig. 64. There is a shape consisting of a curve having a convex region and a concave region toward the outside. Preferred cross-sectional shapes of the lens array 44a include a polygonal shape (that is, a straight line shape) as shown in FIG. 65, and a combination of a straight line and a curve as shown in FIG. When using the shape containing these polygonal shapes or a straight line, it is preferable to set shape especially suitably so that the brightness unevenness of FIG. 74 may not arise. As described above, the maximum value is preferably 60% or less when the ratio of the presence of the angle component at an angle (α ° to α ° + 10 °) is obtained for the angle α ° in the range of 0 to 80 °. Preferably it is 50% or less, More preferably, it is 40% or less. In the case where the cross-sectional shape of the lens rows includes several straight lines, light is reflected by a plane corresponding to each straight line, whereby the effect of enlarging the light is strong, and the reflected angles are significantly different from each other. If it is a structure, light advances to various directions, and the luminance unevenness of FIG. 74 becomes difficult to produce. The preferred shape is the polygonal shape of Fig. 65, wherein the angle formed with the lens row forming surface has a straight line of about 40 °, about 30 °, about 20 °, or about 40 °, about 30 °, about 20 °, It is desirable to have a straight line of about 0 degrees. Moreover, the structure of FIG. 66 which has a straight line which satisfy | fills this condition may be sufficient. Also in these structures, even in the case where the ratio of the presence of the angular component at any angle (α ° to α ° + 10 °) is high, in other angle components, the light is greatly different from the angle component near α °. Since it is reflected, the luminance unevenness of FIG. 74 is unlikely to occur.

In the cross-sectional shape of FIG. 65 and FIG. 66, 2-20 are preferable, as for the number of a straight line (side), 3-15 are more preferable, and 4-10 are still more preferable. When the number of edges is too small, the light does not widen in various directions, and therefore, the luminance unevenness in FIG. 74 tends to occur. On the other hand, when the number of edges is too large, it is difficult to manufacture the light guide member having the lens rows 144a.

The arrangement pitch of the lens rows 144a is preferably in the range of 10 to 100 m, more preferably in the range of 10 to 80 m, still more preferably in the range of 20 to 70 m. In the present invention, the pitch of the lens rows 144a may be the same in all the lens rows 144a as long as it is within the above range, may be partially different, or may be gradually changed.

In the case where the required magnification angle is particularly large, more than 110 °, it is difficult to magnify the light sufficiently with only the lens array extending generally along the direction of directivity of the light guide incident light. In this case, the inclined lens row 150 extending in the direction inclined with respect to the direction (X direction) of the incident light as shown in FIG. 67 is disposed on the light exit surface or the rear surface of the light guide 104. It is preferable. In particular, it is preferable that the lens rows extend in substantially the same direction as the direction corresponding to the required magnification angle. The presence of such an inclined lens row 150 ensures good reflection of incident light components that have the same large angle that are not properly reflected in the lens row 144a so that the traveling direction is changed to an angle that can be properly reflected in the lens row 144a. Can be. The preferable formation position of this inclined lens row 150 is an area | region corresponding to the primary light source of a non-display part correspondence area | region, and when this is not formed, the dark part is passed through the optical deflection element 106, for example, a prism sheet, and it observes it. It is preferable that it is an area | region which becomes. Since light in this area does not face the direction perpendicular to the prism rows of the prism sheet, changing the traveling direction of the light in this area is an effective means for reducing the dark portion in FIG. 73. It is preferable that the inclination-lens row formed has the existence ratio of 20-50 degree angle component computed by the same method as the said lens row 144a is 10 to 80%. If the existence ratio is too small, the action of changing the direction of the light decreases. If the ratio is too large, new bright lines are generated, which is likely to cause new luminance unevenness.

In addition, for the same purpose, the same dot pattern 152 shown in FIG. 68 may be provided on the light exit surface or the back surface of the light guide 104. The dot pattern 152 can be formed by etching, laser processing, or the like. The presence of such a dot pattern 152 ensures that the incident light component, which has a large angle with respect to the direction of directivity of the incident light, is well reflected in the lens column 144a so that the traveling direction is properly reflected in the lens column 144a. Can be changed to any angle. The preferable formation position of this dot pattern is an area | region corresponding between the primary light sources of a non-display part correspondence area | region, and when it is not formed, it is preferable that it is an area | region where a dark part is observed through a prism sheet. Since light in this area does not face the direction perpendicular to the prism rows of the prism sheet, changing the traveling direction of the light at this position is an effective means for reducing the dark portion in FIG. 73. In the cross section orthogonal to the straight line which forms a dot with a primary light source, the shape of each dot of the formed dot pattern WHEREIN: The existence ratio of the 20-80 degree angle component computed by the method similar to the said lens column 144a is 10-80. It is preferable that it is%. If the existence ratio is too small, the action of changing the direction of the light decreases. If the ratio is too large, new bright lines are generated, which is likely to cause new luminance unevenness.

In the present invention, as described above, the lens row forming surface in which the light output mechanism is formed on the light exit surface 143 of the light guide body 104 and the main surface (rear surface) on the opposite side is formed with the lens row 144a. Although it is preferable to set it as this, you may form the light output mechanism which made the light output surface into the formation surface of the lens row 144a, and provided the high light-diffusion area | region in the main surface on the opposite side.

It is a partially exploded perspective view which shows a part of the light guide for surface light source devices which concerns on this invention with LED. In this embodiment, the light incident end surface 141 consists of an anisotropic rough surface. This anisotropic rough surface has a larger average inclination angle θa in the Y direction along the light exit surface 143 than the average inclination angle θa in the Z direction orthogonal to the light exit surface 143. The distribution in the XY plane of light incident in the light guide 4 from the light incident end face 141 generated from 102 can be enlarged. This prevents excessive light emission from the light guide 104 in the vicinity of the light incidence cross section based on excessively expanding the distribution in the XZ plane, thereby efficiently applying a large area to the light exit surface 143. The light of intensity can be led, and it can contribute to the improvement of the uniformity of luminance.

As for the anisotropic rough surface of this light incident end surface 141, the average inclination angle in the Y direction along the light exit surface 143 becomes like this. Preferably it is 3-30 degrees, More preferably, it is 4-25 degrees, Especially preferably, it is 5-20 °. If the average inclination angle is less than 3 °, the above-described effects are less likely to occur. If the average inclination angle is more than 30 °, the distribution of light in the XY plane does not become wider and the luminance tends to be lowered. In addition, in order to obtain said effect, it is preferable that the average inclination angle in the Z direction orthogonal to the light exit surface 143 is 5 degrees or less, especially 3 degrees or less. The anisotropic rough surface of the light incident end surface 141 preferably has a length of 8 ° or more of the inclination angle when measured in the direction along the light exit surface 143 is 5% or less of the previous measurement length. If the length of the region with an inclination angle of 8 ° or more exceeds 5% of the total measurement length, the luminance due to excessive light emission from the light guide 104 near the light incident cross section based on excessively expanding the distribution of light in the XY plane There exists a tendency for a fall to occur. As such anisotropic rough surface, the regular or irregular uneven structure which is substantially parallel to each other extended in the substantially Z direction is preferable. More specifically, the lens row which is substantially parallel to each other extended in the substantially Z direction, or what roughened this lens row is mentioned.

The light guide 104 of this invention can be comprised from the synthetic resin with high light transmittance like what was demonstrated about the light guide 3 in embodiment other than the said FIG. When forming the surface structure of the rough surface of the light guide 104, the surface of prisms, etc., or the anisotropic roughening structure of the light incident cross section, as described in embodiment of the above-mentioned FIG. It may be formed by heat press using a mold member having a shape, and may be shaped simultaneously with molding by screen printing, extrusion molding or injection molding. Moreover, a structural surface can be formed using heat or photocurable resin.

The formation method of the mold member for these shaping | molding is said. In the formation of the high light diffusion region 431 formed in the light guide of the present invention, when forming by roughing surface, a shielding plate or the like having an opening corresponding to the high light diffusion region 431 is provided on the surface of the mold. The method of shielding an outer part, blasting, or etching can be mentioned, and can be formed by transferring this. In particular, when performing blasting with fine particles, by providing the shielding plate at an appropriate distance from the surface of the mold, a region in which the average inclination angle θa gradually decreases can be formed in the outer peripheral portion of the high light diffusion region 431. . In the case of forming a concave-convex structure such as a dot or a volcanic protrusion, a reverse shape of the concave-convex structure may be formed at a predetermined position of the mold, and a method of transferring the concave-convex structure may be mentioned. Similarly, when forming the rough surface as a light output mechanism, the method of shielding an area | region other than the upper side of a metal mold | die with a shielding board, etc., and blasting or etching is mentioned, and installing a shielding plate at a suitable distance from the surface of a metal mold | die is provided. Thereby, the area | region in which the average inclination-angle (theta) a decreases slowly can be formed in the area | region outer peripheral part.

As a method of partially changing the shape of the lens row 144a formed in the light guide of the present invention, a method of blasting part or all of the mold having the lens columnar transfer surface formed by cutting or etching, the lens columnar surface A method of grinding a part or all of a mold having a mold and transferring it, a lens column shape by blasting part or all of a molding obtained by molding using a first mold having a lens thermal shape transfer surface and transferring it again The method of obtaining the 2nd metal mold | die which has a transfer surface, etc. are mentioned. By these methods or by forming a blast trace directly on at least a part of the lens row forming surface of the light guide 104 by blasting, the frequency distribution and valley inclination angle of the cross-sectional shape of the lens row 144a can be changed. .

The flat portion 144b formed on the lens row forming surface of the light guide of the present invention is a method for mirror-polishing a part of a mold having a lens thermal transfer surface by cutting or etching, or applying a lens row to a portion corresponding to the flat portion. It can obtain by not forming. Moreover, after forming a light guide, it can also form by the method of performing mirror polishing or sanding to a light guide directly.

The lens shape formed in the optical deflecting element 106 can be variously used according to the objective, for example, a prism shape, a lenticular lens shape, a fly-eye lens shape, a waveform shape, etc. are mentioned. Especially, the prism sheet by which the several prism rows of substantially triangular cross section was arranged is especially preferable. It is preferable to make the vertex angle of a prism row into the range of 50-80 degrees, More preferably, it is the range of 55-70 degrees.

The optical deflecting element 106 of the present invention can be made of a synthetic resin having a high light transmittance as described with respect to the optical deflecting element 4 in the embodiment other than FIG. In forming a surface structure such as a prism row of the light deflecting element 106, as described in the embodiments other than FIG. 1, the transparent synthetic resin plate is formed by thermally pressing using a mold member having a desired surface structure. You may shape | mold simultaneously with shaping | molding by screen printing, extrusion molding, injection molding, etc. Moreover, a structural surface can be formed using heat or photocurable resin. The mold member for these shaping | molding can be obtained by metal mold | die cutting, an etching, etc. as demonstrated in embodiment other than the said FIG. In addition, a rough surface composed of an active energy ray-curable resin on a transparent base material such as a transparent film or sheet made of polyester resin, acrylic resin, polycarbonate resin, vinyl chloride resin, polymethacrylimide resin, or the like. The structure and the lens array structure may be formed on the surface, and such sheets may be bonded together on separate transparent substrates by a method such as bonding or fusion. As active energy ray hardening type resin, a polyfunctional (meth) acryl compound, a vinyl compound, (meth) acrylic acid ester, an aryl compound, the metal salt of (meth) acrylic acid, etc. can be used.

As the light reflection element 108, as described with respect to the light reflection element 5 in the embodiment of the above-mentioned FIG. 1, for example, a plastic sheet having a metal vapor deposition reflection layer on its surface can be used. In the present invention, it is also possible to use a light reflecting layer or the like formed on the main surface 144 on the side opposite to the light exit surface of the light guide 104 as the light reflecting element 108 by metal deposition or the like. Moreover, it is preferable to attach a reflection member also to four side end surfaces (except the light incident end surface 141) of the light guide 104. As shown in FIG.

Example

Hereinafter, an Example demonstrates this invention.

[Examples 1-11, Comparative Examples 1-5]

By injection molding using acrylic resin (acrylic PET (trade name) manufactured by Mitsubishi Rayon Co., Ltd.), one surface is a mat surface, the other surface has a prism vertex angle of 100 degrees, a front end radius of curvature of 15 µm, and a pitch of 50 µm. A wedge-shaped light guide material was also produced in a square shape, which is a prism pattern arranged so that the prism rows were parallel to the short sides. The following black ink is applied to the mat surface of the light guide material on which the prism pattern is formed by screen printing from the longer side of the thicker one to various widths (Examples 1 to 11 and Comparative Examples 1 to 5). 1 The light absorption band corresponding part was formed. In this manner, the visible light transmittance of the ultraviolet curable black ink when the black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance was 30%. At the same time, black ink was applied by screen printing to form a second light absorption band in an area away from the first light absorption band counterpart. In such a manner, the visible light transmittance of the ultraviolet curable black ink when the black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance was 80%.

Black ink:

Acrylic acid: 45% by weight

Isobulin acrylate: 17% by weight

1, 6 hexanegiol acrylate: 15% by weight

Tetrahydrofurfuryl acrylate: 15% by weight

Benzophenone: 3 wt%

Carbon Black: 5 wt%

Next, the light incident end surface and the first light absorption band formed as the cut surface are further cut by performing a cutting process on the light incident end face corresponding portion of the light guide material to cut off an unnecessary part including a part of the first light absorption band corresponding part. A light guide having a second light absorption band was obtained. The light guide has a wedge shape of 230 mm x 290 mm and a thickness of 2.2 mm-0.7 mm, the radius of curvature R of the edge portion is 40 m, and the distance D1 to the light incident cross section is 0 m. The width W1 of the light absorption band, the distance D2 between the light incident end face and the second light absorption band, and the width W2 of the second light absorption band were as follows.

Example 1 ---- W1 = 500 µm, D2 = 1000 µm, W2 = 200 µm

Example 2 ---- W1 = 400 μm, D2 = 1000 μm, W2 = 200 μm

Example 3 ---- W1 = 300 mu m, D2 = 1000 mu m, W2 = 200 mu m

Example 4 ---- W1 = 200 µm, D2 = 1000 µm, W2 = 200 µm

Example 5 ---- W1 = 150 µm, D2 = 1000 µm, W2 = 200 µm

Example 6 ---- W1 = 75 μm, D2 = 1000 μm, W2 = 200 μm

Example 7 ---- W1 = 300 µm, D2 = 1100 µm, W2 = 700 µm

Example 8 ---- W1 = 300 µm, D2 = 900 µm, W2 = 300 µm

Example 9 ---- W1 = 300 µm, D2 = 900 µm, W2 = 150 µm

Example 10 ---- W1 = 300 µm, D2 = 900 µm, W2 = 75 µm

Example 11 ---- W1 = 300 µm, D2 = 1100 µm, W2 = 200 µm

Comparative Example 1-W1 = 20 µm, D2 = 900 µm, W2 = 200 µm

Comparative Example 2-W1 = 800 µm, D2 = 900 µm, W2 = 200 µm

Comparative Example 3 ---- W1 = 300 µm, D2 = 2700 µm, W2 = 200 µm

Comparative Example 4-W1 = 300 µm, D2 = 400 µm, W2 = 1000 µm

Comparative example 5 ---- W1 = 20 micrometers, D2 = 900 micrometers, W2 = 200 micrometers (The light absorption band of 20 micrometers width is formed continuously also in the light incident end surface side.).

A light source reflector having a strong tendency to specularly reflect the cold cathode tube along a long side thereof so as to face one side cross-section (cross section of a side of thickness 2.2 mm) corresponding to the side (long side) of the light guide 290 mm in length (long side). 4 films) and covered. In addition, the light diffusion reflecting film (E60 (brand name) by Toray Corporation) was attached to the other side end surface, and the reflecting sheet was arrange | positioned so as to oppose the surface (rear surface) of a prism array. The above configuration was assembled into the frame. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

Here, the light source reflector is wound from the outer edge of the light reflecting element through the outer surface of the primary light source to the light exit surface end edge of the light guide, and the first and second light absorption bands are led by the end edge of the light source reflector. In order to be covered, the edge of the light source reflector was only 1.3 mm from the light guide end face of the light guide and projected upward of the light exit surface. In addition, the frame was made to shield the area | region of width 2.5mm of the outer peripheral part of a light guide body light emission surface (namely, so that the width | variety of a frame shape area might be 2.5mm). That is, the edge part of the light source reflector was located in the frame shape area | region, and the 1st and 2nd light absorption bands were located in the frame shape area | region, ie, out of the effective light emission area of the surface light source device.

On the other hand, using an acrylic ultraviolet curable resin having a refractive index of 1.5064, a convex curved shape having a curvature radius of one prism face of 400 µm, a planar shape of the other prism surface, and a large number of prism rows having a pitch of 50 µm in parallel The prism sheet | seat which formed the spread prism heat | fever on one surface of the polyester film of thickness 125micrometer was produced.

The prism sheet to be obtained has the prism column forming surface facing the light exit surface (mat surface) side of the light guide, the ridge line of the prism row parallel to the light incident cross section of the light guide, and the prism row of the light guide The lower surface was mounted so that the shape prism faced.

In the surface light source devices of Examples 1 to 11 and Comparative Examples 1 to 5 obtained as described above, the light emitting surface was observed by turning on the primary light source under the same conditions. The bright line and the dark line in the vicinity of the cross section were inconspicuous to the extent that the actual use is not impaired, and the decrease in the overall luminance was such that the use was not actually impaired. Especially, the thing of Examples 4 and 7 was the most favorable. In addition, in Examples 1-5, 7-9, and 11, the bright line and dark line in the vicinity of the light-guide light incident cross section were hardly recognized. In Examples 2-6 and 8-11, the fall of the whole brightness was hardly recognized. On the other hand, in the comparative example 1, the clear bright line in the vicinity of the light-guide light incident cross section was recognized, and in the comparative example 2, the brightness in the vicinity of the light-guide light incident cross section was compared with the thing of Examples 1-11. Was recognized, and in Comparative Examples 3 and 4, bright lines and dark lines in the vicinity of the light guide cross-section of light guides were recognized as compared with those of Examples 1 to 11, and in Comparative Example 5, Example 1 Compared with the thing of -11, the fall of the whole brightness | luminance and the dark line in the effective light emission area were recognized.

Example 12

In the same manner as in Example 1, a light guide material was produced. Thereafter, cutting was performed on the light incident end surface corresponding portion of the light guide material to obtain a light guide having a light incident end surface formed as a cutting surface. The light guide was in the shape of a wedge substrate having a thickness of 230 mm x 290 mm and a thickness of 2.2 mm to 0.7 mm. On the mat surface of the light guide material on which the prism pattern is formed, a plurality of ultraviolet curable black inks are dropped by the inkjet method under the following conditions, and the width W1 'as shown in FIG. 12 is about 300. A large number of mutually independent first light absorption band ink dots having a diameter of about 70 µm were formed in an area having a distance D1 'of about 60 µm with a thickness of about µm. At the same time, a large number of mutually independent second light absorption band ink dots of about 70 mu m in diameter were formed by the inkjet method. In this state, the ink dot is leveled for 5 seconds, and the first light absorption band ink is continuously continuous over the entire area with a width W1 of about 400 mu m and a distance D1 of about 10 mu m as shown in FIG. Formed a layer. At the same time, the second light absorption band ink layer was formed by the same leveling. At that point, ultraviolet rays were irradiated to cure the ink layer to form substantially linear first and second light absorption bands.

Inkjet method:

Head speed: 400mm / s

Head temperature: 55 ℃

Piezoelectric element feeding method

UV curable black ink (ink 95 wt% + methylmethacrylate 5 wt%):

Ink composition:

Acrylic acid: 42% by weight

Isobulin acrylate: 15% by weight

1, 6 hexanegiol acrylate: 20% by weight

Acrylic amine / acrylic acid ester mixture: 15% by weight

Benzophenone: 3 wt%

Carbon Black: 5 wt%

Ink Viscosity (55 ° C): 10cp

Ink Surface Tension (55 ℃): 30mN / m

In the same manner, the visible light transmittance of the ultraviolet curable black ink when printing the ultraviolet curable black ink with a transparent acrylic plate having a thickness of 2 mm and having a size capable of measuring the visible light transmittance was 20% for the first light absorption band. The second light absorption band was 80%.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflecting film, and the reflection sheet like Example 1, and the structure obtained by this was assembled to the frame. In this light guide, the maximum peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light exit surface normal direction, and the full width at half maximum was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 1, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted on the light incident end surface so that the planar prism surface of each prism row might face.

About the surface light source device obtained as mentioned above, when the primary light source was lighted and the light emitting surface was visually observed, the bright line and dark line in the vicinity of the light-guide light incident cross section were hardly noticeable.

Comparative Example 6

The light guide material similar to Example 1 was produced, and the cutting process with respect to the light incident cross section corresponding part of the light guide material was performed, and the light guide body which has the light incidence cross section formed as a cutting surface was obtained. In this comparative example, no light absorption band was formed.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflecting film, and the reflection sheet like Example 1, and the structure obtained by this was assembled to the frame. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 1, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident end surface of the light guide, It mounted on the light incident end surface so that the planar prism surface of each prism row might face.

With respect to the surface light source device obtained as described above, the primary light source was turned on under the same conditions as in Example 12, and the light emitting surface was visually observed. As a result, a clear bright line in the vicinity of the light guide cross section was recognized.

Example 13

In the same manner as in Example 1, a light guide material was produced. Thereafter, cutting was performed on the light incident end surface corresponding portion of the light guide material to obtain a light guide having a light incident end surface formed as a cutting surface. The light guide was in the shape of a wedge substrate having a thickness of 230 mm x 290 mm and a thickness of 2.2 mm to 0.7 mm. On the mat surface of the light guide material on which this prism pattern was formed, as in Example 12, a plurality of ultraviolet curable black inks were dropped by the inkjet method, and the width W1 'as shown in FIG. 12 was about 300 µm. A plurality of mutually independent first light absorption band ink dots having a diameter of about 70 mu m were formed in a region where the furnace distance D1 'was about 60 mu m. At the same time, a large number of mutually independent second light absorption band ink dots of about 70 mu m in diameter were formed by the inkjet method. Immediately thereafter, ultraviolet rays were irradiated to cure the ink dots so as not to level the ink dots, thereby forming substantially linear first and second light absorption bands.

In the same manner, the visible light transmittance of the ultraviolet curable black ink when the ultraviolet curable black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance was 20% for the first light absorption band. The second light absorption band was 80%.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflecting film, and the reflection sheet like Example 1, and the structure obtained by this was assembled to the frame. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 1, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted on the light incident end surface so that the lower surface prism surface of each prism line might face.

In the surface light source device obtained as described above, the primary light source was turned on under the same conditions as in Example 12, and the light emitting surface was visually observed. As a result, a decrease in luminance was recognized slightly compared with that in Example 12. In the vicinity of the body light incident cross-section, some bright lines were recognized.

Example 14

In the same manner as in Example 12, cutting was performed on the light incident end surface corresponding portion of the light guide material, thereby obtaining a light guide having a light incident end face formed as a cutting surface. By the cutting process, the protrusion which protruded and protruded with respect to the other area | region of a light exit surface was formed in the boundary between a light incident cross section and a light exit surface. The height of this protrusion was 10 mu m, and the full width at half maximum was 100 mu m. In the same manner as in Example 12, an ink layer was formed by forming and leveling ink dots. However, the position of the formation area of the said ink dot with respect to a 1st light absorption band was set so that an ink layer might reach a protrusion part by leveling.

In the surface light source device obtained in the same manner as in Example 12 using the obtained light guide, the primary light source was turned on and the light emitting surface was visually observed. The cancer line was barely noticeable.

[Examples 15-23, Comparative Examples 7-9]

By injection molding using acrylic resin (acrylic pet [trade name] manufactured by Mitsubishi Rayon Co., Ltd.), one side is a mat surface, the other surface is a prism vertex angle of 100 degrees, a front end radius of curvature l5 μm, a pitch of 50 μm. A wedge-shaped light guide member was produced in a rectangular shape, which is a prism row forming surface having a prism pattern arranged so that the prism rows are parallel to the short sides. However, this light guide material does not form a prism row in the whole of the said other surface in which the prism row was formed, but has various width | variety from the longer side of the thicker one (Examples 15-23 and Comparative Examples 7-9). ) Has a region consisting of a substantially flat surface at approximately the same height position as the curve of the prism rows, and also has a transition region having a width of 500 µm gradually shifting from the flat surface to the prism row forming surface.

The following black ink is applied to the substantially flat surface area of the prism thermal forming surface of this light guide material by screen printing from the longer side of the thicker one by various widths (Examples 15 to 23 and Comparative Examples 7 to 9). The light absorption band corresponding part was formed. Substantially no occurrence of ink transfer to the transition region and the prism row forming surface region. In addition, the visible light transmittance of the ultraviolet curable black ink when printing black ink in the size which can measure visible light transmittance on the transparent acrylic plate of thickness 2mm was 30%.

Black ink:

Acrylic acid: 45% by weight

Isobulin acrylate: 17% by weight

1, 6 hexanegiol acrylate: 15% by weight

Tetrahydrofurfuryl acrylate: 15% by weight

Benzophenone: 3 wt%

Carbon Black: 5 wt%

Next, by cutting the light incident end face corresponding portion of the light guide material and cutting the unnecessary portion including a part of the light absorption band corresponding part, a light guide having a light incident end face formed as the cut surface and the light absorption band was obtained. . The light guide has a shape of a wedge substrate of 230 mm x 290 mm and a thickness of 2.6 mm-0.7 mm, the radius of curvature R of the edge portion is 40 µm, and the width of the light absorption band having a distance of 0 µm from the light incident surface is It was as follows. Further, the light guide material was fabricated so that the width of the substantially flat surface region of the obtained light guide was about 50 µm larger than the width of the light absorption band.

Example 15 ---- 800 μm

Example 16-700 μm

Example 17 ---- 600 μm

Example 18 ---- 500 μm

Example 19 ---- 400 μm

Example 20 ---- 300 μm

Example 21 ---- 200 μm

Example 22 ---- 150 μm

Example 23 ---- 75 μm

Comparative Example 7 ---- 20 μm

Comparative Example 8 ---- 1500 μm

Comparative Example 9-20 micrometers (The light absorption band of 20 micrometers width is formed continuously also in the light incident end surface side.).

Opposite the side cross-section (cross section on the side of 2.6 mm in thickness) corresponding to the side (long side) of the light guide body 290 mm in length, and along the long side, the cold cathode tube is turned into a light source reflector (silver reflective film made by Placed overcover. In addition, the light diffusion reflecting film (E60 (brand name) by Toray Corporation) was attached to the other side end surface, and the reflecting sheet was arrange | positioned so as to oppose the surface (rear surface) of a prism array. The above structure was assembled to the frame body. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

Here, the light source reflector is wound from the outer edge of the light guide surface to the edge of the light guide light exit surface through the outer surface of the primary light source, and the light absorption band is covered by the edge of the light source reflector (except for comparison). Example 8 extruded the edge of the light source reflector only 1.3 mm from the light guide light incident end face upward so that a part of the light absorption band was covered by the end edge portion of the light source reflector. Moreover, the frame was made to shield the area | region of width 2.5mm of the outer periphery of the light guide light exit surface (that is, the width | variety of the frame-shaped area | region was 2.5 mm). In other words, the end edge portion of the light source reflector was located in the frame-shaped region, and the light absorption band was located in the frame-shaped region, that is, outside the effective light emitting region of the surface light source device.

On the other hand, using an acrylic UV curable resin having a refractive index of 1.5064, one prism face has a radius of curvature of 400 μm, the other prism face has a planar shape, and a plurality of prism rows having a pitch of 50 μm are arranged in parallel. The prism sheet | seat which formed the spread prism heat | fever on one surface of the polyester film of thickness 125micrometer was produced.

The prism sheet forming surface of the resultant prism sheet faces the light exit surface (mat surface) side of the light guide, the ridge line of the prism row is parallel to the light incident cross section of the light guide, and the prism rows of the light guide The lower surface was mounted so that the shape prism faced.

In the surface light source devices of Examples 15 to 23 and Comparative Examples 7 to 9 obtained as described above, the primary light source was turned on under the same conditions and the light emitting surface was visually observed. The bright line and the dark line in the vicinity of the light incident cross section were not so noticeable as to be practically uninterrupted to use, and the decrease in the overall brightness was not such a problem as to actually be used. The clear bright line near the cross section was recognized, and in the comparative example 8, the fall of the brightness in the vicinity of the light guide light incident cross section was recognized compared with the thing of Examples 15-23, In the comparative example 9 Compared with those of Examples 15 to 23, the decrease in luminance and dark lines in the display area were recognized.

Example 24

In the same manner as in Example 15, a light guide material was produced. Thereafter, cutting was performed on the light incident end surface corresponding portion of the light guide material to obtain a light guide having a light incident end surface formed as a cutting surface. The light guide was in the shape of a wedge substrate having a thickness of 230 mm 290 mm and a thickness of 2.6 mm-0.7 mm. In the substantially flat surface area of about 400 micrometers in width of the prism heat forming surface (rear surface) of the light guide material which formed this prism pattern, many ultraviolet-curable black ink of the following is droplet-ized by the inkjet method, and it shows in FIG. A large number of independent ink dots having a diameter of about 70 µm were formed in an area having a width W 'of about 210 µm and a distance D' of about 60 µm. By leveling the ink dots in that state for 5 seconds, a continuous ink layer was formed over the entire area in the region having a width W of about 300 µm and a distance D of about 10 µm as shown in FIG. At that point, ultraviolet rays were irradiated to cure the ink layer, thereby forming a substantially linear light absorption band.

Inkjet method:

Head speed: 400mm / s

Head temperature: 55 ℃

Piezoelectric element feeding method

UV curable black ink (ink 95 wt% + methylmethacrylate 5 wt%):

Ink composition:

Acrylic acid: 42% by weight

Isobulin acrylate: 15% by weight

1, 6 hexanegiol acrylate: 20% by weight

Acrylic amine / acrylic acid ester mixture: 15% by weight

Benzophenone: 3 wt%

Carbon Black: 5 wt%

Ink Viscosity (55 ° C): 10cp

Ink Surface Tension (55 ℃): 30mN / m

In the same manner, the visible light transmittance of the ultraviolet curable black ink was 20% when the ultraviolet curable black ink was printed with a transparent acrylic plate having a thickness of 2 mm and the visible light transmittance was measured.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflection film, and the reflection sheet like Example 15, and the structure obtained by this was assembled to the frame body. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 15, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted on the light incident end surface so that the planar prism surface of each prism row might face.

About the surface light source device obtained as mentioned above, when the primary light source was lighted and the light emitting surface was visually observed, the bright line and dark line in the vicinity of the light-guide light incident cross section were hardly noticeable.

Comparative Example 10

The light guide material like Example 15 was produced, and the cutting process with respect to the light incident cross section corresponding part of the light guide body material was performed, and the light guide body which has the light incidence cross section formed as a cutting surface was obtained. In this comparative example, no light absorption band was formed.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflection film, and the reflection sheet like Example 15, and the structure obtained by this was assembled to the frame body. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 15, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted on the light incident cross section so that the lower surface prism surface of each prism row faced.

With respect to the surface light source device obtained as described above, the primary light source was turned on under the same conditions as in Example 24, and the light emitting surface was visually observed, and clear bright lines in the vicinity of the light guide cross section were recognized.

Example 25

In the same manner as in Example 15, a light guide material was produced. Thereafter, cutting was performed on the light incident end surface corresponding portion of the light guide material to obtain a light guide having a light incident end surface formed as a cutting surface. The light guide was in the shape of a wedge substrate having a thickness of 230 mm 290 mm and a thickness of 2.6 mm-0.7 mm. In the substantially flat surface area of about 400 micrometers in width of the prism heat forming surface (rear surface) of the light guide material which formed this prism pattern, many ultraviolet curable black ink was droplet-ized by the inkjet method like Example 24, and A large number of ink dots having a diameter of about 70 mu m were formed in a region having a width W 'of about 210 mu m and a distance D' of about 60 mu m as shown in FIG. Immediately thereafter, ultraviolet rays were irradiated to cure the ink dots so as not to level the ink dots, thereby forming a substantially linear light absorption band. In this light absorption band, each ink dot was located independently of each other, the width was about 210 micrometers, and the distance from the light incident cross section was about 60 micrometers.

In the same manner, the visible light transmittance of the ultraviolet curable black ink was 20% when the ultraviolet curable black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflection film, and the reflection sheet like Example 15, and the structure obtained by this was assembled to the frame body. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 15, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted on the light incident end surface so that the planar prism surface of each prism row might face.

In the surface light source device obtained in the above manner, when the primary light source was turned on under the same conditions as in Example 24, and the light emitting surface was visually observed, a decrease in luminance was recognized slightly compared with that in Example 24, and the light guide was also observed. Some bright lines were recognized near the body light incident cross section.

[Examples 26-34, Comparative Examples 11-13]

In the same manner as in Example 15, the prism pattern is arranged such that one surface is a mat surface, and the other surface is parallel to a short side of a prism vertex angle of 100 degrees, a front end radius of curvature radius of 15 µm, and a pitch of 50 µm. A wedge-shaped light guide member was produced in a rectangular shape, which is a prism heat-forming surface having a surface. However, this light guide material material does not form a prism row in the whole of the said other surface in which the prism row was formed, but it extended from the long side of the thicker one in various widths (Examples 26-34 and Comparative Examples 11-13). It was set as having the area | region which consists of a substantially flat surface located in the height position substantially the same as the ridgeline of a prism row, and has a transition area | region of 50 micrometers in width which gradually transitions from a flat surface to a prism row formation surface. In the substantially flat surface area of the prism row forming surface of this light guide material material, it is carried out similarly to Example 15, except for the screen which is wide in the width | variety (extensions 26-34 and comparative examples 11-13) from the longer side of a thicker one. Black ink was apply | coated by printing and the light absorption band correspondence part was formed. There was no occurrence of ink transfer to the transition region and prism row forming surface region. In addition, the visible light transmittance of the ultraviolet curable black ink when printing black ink in the size which can measure visible light transmittance on the transparent acrylic plate of thickness 2mm was 40%. Further, black ink was applied to the mat surface of the light guide material by screen printing as in Example 6 to form a light absorption band corresponding portion.

Next, by cutting the light incident end face corresponding portion of the light guide material and cutting off unnecessary parts including a part of the light absorption band corresponding parts on both sides of the light guide material, A light guide having a light absorption band was obtained. The light guide has a wedge shape of 230 mm x 290 mm and a thickness of 2.6 mm-0.7 mm, the radius of curvature R of the edge portion is 40 µm, and the light absorption band on the back side with a distance of 0 µm from the light incident surface. The width of was as follows. Further, the light guide material was fabricated such that the width of the substantially flat surface area of the obtained light guide was about 100 [mu] m larger than the width of the light absorption band.

Example 26-800 μm

Example 27 ---- 700 μm

Example 28 ---- 600 μm

Example 29 ---- 500 μm

Example 30 ---- 400 μm

Example 31 ---- 300 μm

Example 32 ---- 200 μm

Example 33 ---- 150 μm

Example 34 ---- 75 μm

Comparative Example 11 ---- 20 μm

Comparative Example 12-1500 µm

Comparative Example 13-20 micrometers (The light absorption band of 20 micrometers width is formed continuously also in the light incident end surface side.).

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflecting film, and the reflecting sheet like Example 15, and the structure obtained by this was assembled to the frame. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

Here, the light source reflector is wound around the outer edge of the light guide from the outer edge of the primary light source to the edge of the light guide light exit surface, and the light absorption band is covered by the end edge of the light source reflector (Comparative Example 12 The edge of the light source reflector protruded only 1.3 mm above the back surface of the light guide body and above the light exit surface so that a part of the light absorption band was covered by the end edge portion of the light source reflector. In addition, the frame body shielded the area | region of width 2.5mm of the outer peripheral part of the light guide body light emission surface (namely, so that the width | variety of the frame frame area might be 2.5mm). That is, the edge part of the light source reflector was located in the frame shape area | region, and the light absorption band was located in the frame shape area | region, ie, out of the effective light emission area | region of the surface light source device.

In the prism sheet produced in the same manner as in Example 15, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted to the light incident cross section so that the planar prism surface of each prism row might face.

In the surface light source devices of Examples 26 to 34 and Comparative Examples 11 to 13 obtained as described above, the light emitting surface was visually observed by lighting the primary light source under the same conditions. The bright lines and dark lines in the vicinity of the light incident cross section were hardly noticeable, but in the comparative example 11, clear bright lines in the vicinity of the light guide cross section of the light guide were recognized. The lowering of the brightness in the vicinity of the light guide cross section of light guide was recognized as compared with the 34th, and in the comparative example 13, the lowering of luminance and dark lines in the display area were recognized as compared with those of Examples 26 to 34. .

Example 35

In the same manner as in Example 26, a light guide material was produced. Thereafter, cutting was performed on the light incident end surface corresponding portion of the light guide material to obtain a light guide having a light incident end surface formed as a cutting surface. The light guide was in the shape of a wedge substrate having a thickness of 230 mm 290 mm and a thickness of 2.6 mm-0.7 mm. In the substantially flat surface area of about 250 μm in width of the prism row forming surface (rear surface) of the light guide, a plurality of independent ink dots are formed by the inkjet method as in Example 24, and the ink dots are leveled. As a result, a continuous ink layer was formed over the entirety in the region where the width W as shown in FIG. 29 was about 150 µm and the distance D was about 10 µm. At that point, ultraviolet rays were irradiated to cure the ink layer, thereby forming a substantially linear light absorption band. In the same manner, the visible light transmittance of the ultraviolet curable black ink was 40% when the ultraviolet curable black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance.

Further, by forming a plurality of independent ink dots on the light exit surface of the light guide by the same inkjet method as in Example 24 and leveling the ink dots, the distance from the light incident end face at a width of about 250 μm. The continuous ink layer was formed in the whole about 10 micrometers. At that point, ultraviolet rays were irradiated to cure the ink layer, thereby forming a substantially linear light absorption band. In the same manner, the visible light transmittance of the ultraviolet curable black ink was 20% when the ultraviolet curable black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflecting film, and the reflecting sheet like Example 15, and the structure obtained by this was assembled to the frame. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 15, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted on the light incident end surface so that the planar prism surface of each prism row might face.

In the surface light source device obtained as mentioned above, when the primary light source was turned on and the light emitting surface was visually observed, the bright line and dark line in the vicinity of the light-guide light incident cross section were hardly noticeable.

[Examples 36-46, Comparative Examples 14-18]

In the same manner as in Example 15, the prism pattern is arranged such that one surface is a mat surface, and the other surface is parallel to a short side of a prism vertex angle of 100 degrees, a front end radius of curvature radius of 15 µm, and a pitch of 50 µm. A wedge-shaped light guide member was produced in a rectangular shape, which is a prism heat-forming surface having a surface. However, this light guide material material does not form a prism row in the whole of the said other surface in which the prism row was formed, but various width | variety from the longer side of the thicker one (Examples 36-46 and Comparative Examples 14-18). It is assumed that it has a region consisting of a substantially flat surface that is at substantially the same height position as the ridge line of the prism rows, and has a transition region having a width of 50 µm gradually shifting from the flat surface to the prism row forming surface. On the substantially flat surface area of the prism thermal forming surface of this light guide material material, black color is screen-printed by the same screen printing as Example 15 in various width | variety (Examples 36-46 and Comparative Examples 14-18) from the longer side of a thicker one. Ink was applied to form a first light absorption band corresponding portion. In such a manner, the visible light transmittance of the ultraviolet curable black ink when the black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance was 30%. At the same time, black ink was applied by screen printing to form a second light absorption band in an area away from the first light absorption band corresponding portion. In such a manner, the visible light transmittance of the ultraviolet curable black ink when the black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance was 80%.

Next, the light incident end surface and the first light absorption band formed as the cut surface are further cut by performing a cutting process on the light incident end face corresponding portion of the light guide material to cut off an unnecessary part including a part of the first light absorption band corresponding part. A light guide having a second light absorption band was obtained. The light guide has a wedge shape of 230 mm x 290 mm and a thickness of 2.6 mm-0.7 mm, the radius of curvature R of the edge portion is 40 m, and the distance D1 to the light incident cross section is 0 m. The width W1 of the light absorption band, the distance D2 between the light incident end face and the second light absorption band, and the width W2 of the second light absorption band were as follows. In addition, the light guide material was produced such that the approximately flat surface area of the light guide obtained can exist only to a position far from the light incidence end face only about 100 탆 from the side edge far from the light incidence end face of the second light absorption band.

Example 36 ---- W1 = 500 µm, D2 = 1000 µm, W2 = 200 µm

Example 37 ---- W1 = 400 μm, D2 = 1000 μm, W2 = 200 μm

Example 38 ---- W1 = 300 µm, D2 = 1000 µm, W2 = 200 µm

Example 39 ---- W1 = 200 µm, D2 = 1000 µm, W2-200 µm

Example 40 ---- W1 = 150 μm, D2 = 1000 μm, W2 = 200 μm

Example 41 ---- W1 = 75 µm, D2 = 1000 µm, W2 = 200 µm

Example 42 ---- W1 = 300 µm, D2 = 1100 µm, W2 = 700 µm

Example 43 ---- W1 = 300 µm, D2 = 900 µm, W2 = 300 µm

Example 44 ---- W1 = 300 µm, D2 = 900 µm, W2 = 150 µm

Example 45 ---- W1 = 300 µm, D2 = 900 µm, W2 = 75 µm

Example 46 ---- W1 = 300 µm, D2 = 1100 µm, W2 = 200 µm

Comparative Example 14-W1 = 20 µm, D2 = 900 µm, W2 = 200 µm

Comparative Example 15-W1 = 800 µm, D2 = 900 µm, W2 = 200 µm

Comparative Example 16-W1 = 300 µm, D2 = 2700 µm, W2 = 200 µm

Comparative Example 17 ---- W1 = 300 µm, D2 = 400 µm, W2 = 1000 µm

Comparative example 18 ---- W1 = 20 micrometers, D2 = 900 micrometers, W2 = 200 micrometers (The light absorption band of 20 micrometers width is formed continuously also in the light incident end surface side.).

A light source reflector having a strong tendency to specularly reflect the cold cathode tube along a long side thereof, corresponding to a side cross section (a cross section of the side having a thickness of 2.6 mm) corresponding to the side (long side) of the light guide 290 mm in length (long side). 4 films) and covered. In addition, the light diffusion reflecting film (E60 (brand name) by Toray Corporation) was attached to the other side end surface, and the reflecting sheet was arrange | positioned so as to oppose the surface (rear surface) of a prism array. The above configuration was assembled to the frame. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

Here, the light source reflector may be wound around the edge of the light guide light exit surface from the outer edge of the end edge portion of the light guide back surface to the outer edge of the primary light source, such that the first light absorption band and the second light absorption band are at the end edges of the light source reflector. If the edge of the light source reflector is only 1.3 mm from the light guide cross-section, the edge of the light source reflector is covered by the negative side so that part of the second light absorption band is covered by the edge of the light source reflector. To protrude upward. In addition, the frame body was made to shield the area | region of width 2.5mm of the outer peripheral part of a light guide body light emission surface (namely, so that the width | variety of a frame shape area might be 2.5mm). That is, the edge portion of the light source reflector is located in the frame region, and the first and second light absorption bands are located in the frame frame region, i.e., outside the effective light emission region of the surface light source device. The second light absorption band was located outside the frame region, that is, within the effective light emitting region of the surface light source device.

In the prism sheet produced in the same manner as in Example 15, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, and the light guide is On the light incidence end face side, so as to face the planar prism face of each prism row.

In the surface light source devices of Examples 36 to 46 and Comparative Examples 14 to 18 obtained as described above, the primary light source was turned on under the same conditions and the starting surface was visually observed. The bright line and the dark line in the vicinity of the light incident cross section are inconspicuous to the extent that the use is not really impaired, and the decrease in the overall luminance is such that the actual use is not impaired. Especially, the thing of Examples 39 and 43 was the best. Moreover, in Examples 36-40, 42-44, and 46, the bright line and the dark line in the vicinity of the light-guide light incident cross section were hardly recognized. In Examples 37-41 and 43-46, the fall of the whole brightness was hardly recognized. On the other hand, in the comparative example 14, the clear bright line in the vicinity of the light-guide light incident cross section was recognized, and in the comparative example 15, the brightness in the vicinity of the light-guide light incident cross section was compared with the thing of Examples 36-46. Was recognized, and in Comparative Examples 16 and 17, bright lines and dark lines in the vicinity of the light guide cross-section of light guides were recognized as compared with those of Examples 36 to 46, and in Comparative Example 18, Example 36 Compared with the thing of -46, the fall of the whole brightness | luminance and the dark line in the effective light emission area were recognized.

Example 47

In the same manner as in Example 36, a light guide material was produced. Thereafter, cutting was performed on the light incident end surface corresponding portion of the light guide material to obtain a light guide having a light incident end surface formed as a cutting surface. The light guide was in the shape of a wedge substrate having a thickness of 230 mm 290 mm and a thickness of 2.6 mm-0.7 mm. In the substantially flat surface area of about 110 탆 in width of the prism thermal forming surface (rear surface) of this light guide, many ultraviolet curable black ink is droplet-ized by the inkjet method like Example 24, and it is shown in FIG. A large number of mutually independent first light absorption band ink dots having a diameter of about 70 µm were formed in an area having a width W1 'of about 300 µm and a distance D1' of about 60 µm. At the same time, a large number of mutually independent second light absorption band ink dots of about 70 mu m in diameter were formed by the inkjet method. In this state, the ink dot is leveled for 5 seconds, and the first light absorption band ink is continuously continuous over the entire area of the width W1 as shown in Fig. 45 and the distance D1 is about 10 m. Formed a layer. At the same time, the second light absorption band ink layer was formed by the same leveling. At that point, ultraviolet rays were irradiated to cure the ink layer to form substantially linear first and second light absorption bands.

In the same manner, when the ultraviolet curable black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance, the visible light transmittance of the ultraviolet curable black ink was 20% for the first light absorption band. , The second light absorption band was 80%.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflection film, and the reflection sheet like Example 15, and the structure obtained by this was assembled to the frame body. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 15, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted on the light incident end surface so that the planar prism surface of each prism row might face.

About the surface light source device obtained as mentioned above, when the primary light source was lighted and the light emitting surface was visually observed, the bright line and dark line in the vicinity of the light-guide light incident cross section were hardly noticeable.

Example 48

In the substantially flat surface area of the prism row forming surface (rear surface) of the light guide body obtained in Example 47, many ultraviolet curable black ink is droplet-ized by the inkjet method like Example 47, and is shown in FIG. A plurality of mutually independent first light absorption band ink dots having a diameter of about 70 µm were formed in an area having the same width W1 'of about 300 µm and a distance D1' of about 60 µm. At the same time, a large number of mutually independent second light absorption band ink dots of about 70 mu m in diameter were formed by the inkjet method. Immediately thereafter, ultraviolet rays were irradiated to cure the ink dots so as not to level the ink dots, thereby forming substantially linear first and second light absorption bands. In the same manner, the visible light transmittance of the ultraviolet curable black ink when the ultraviolet curable black ink was printed on a transparent acrylic plate having a thickness of 2 mm in a size capable of measuring the visible light transmittance was 20% for the first light absorption band. The second light absorption band was 80%.

The obtained light guide body was combined with the cold cathode tube, the light source reflector, the light-diffusion reflection film, and the reflection sheet like Example 15, and the structure obtained by this was assembled to the frame body. As for this light guide, the largest peak of the emitted light intensity distribution (XZ plane) was 70 degrees with respect to the light emission surface normal direction, and the full width at half value was 22.5 degrees.

In the prism sheet produced in the same manner as in Example 15, the prism row forming surface faces the light exit surface (mat surface) side of the light guide, and the ridge line of the prism row is parallel to the light incident cross section of the light guide, It mounted on the light incident cross section so that the lower surface prism surface of each prism row faced.

As for the surface light source device obtained as mentioned above, when the primary light source was lighted on the same conditions as Example 47, and the light emitting surface was visually observed, the fall of brightness was recognized slightly compared with the thing of Example 47, and further light guide was performed. In the vicinity of the body light incident cross-section, some bright lines were recognized.

Example 49

A light guide was obtained in the same manner as in Example 47. By the cutting process, the protrusion which protruded protruded with respect to the other area | region of the substantially flat surface area | region was formed in the boundary between the light incident cross section and the substantially flat surface area | region of the back surface. The height of this protrusion was 10 mu m, and the full width at half maximum was 100 mu m. In the same manner as in Example 47, an ink layer was formed by forming and leveling ink dots. However, the position of the formation area of the said ink dot with respect to a 1st light absorption band was set so that an ink layer might reach a protrusion part by leveling.

With respect to the surface light source device obtained in the same manner as in Example 47 using the obtained light guide member, the primary light source was turned on and the light emitting surface was visually observed, whereby bright lines and dark lines in the vicinity of the light guide cross section of the light guide body were almost inconspicuous. Did.

Example 50

As mentioned above, the light guide for surface light source devices which concerns on this invention, and the surface light source device using the same were produced.

Further, in the present embodiment, the measurement of the inclination angle of the small region of the light guide cross-sectional shape makes a copy of the lens row forming surface of the light guide, cuts it into a plane orthogonal to the extending direction of the lens row, and cuts the cut end optically. It carried out based on the cross-sectional shape line obtained by enlarging with a microscope, an atomic microscope, or other imaging means. Calculation of the frequency distribution of the absolute value of the small area inclination angle and calculation of the valley inclination angle were performed as described with reference to FIG. 55. However, as described above, when the microscopic area is set by dividing the cross-sectional shape into equal parts, measurement of the coordinates of the cross-sectional shape may be complicated. In that case, calculation can be performed simply by the following method.

First, the cut section is divided so that the Y coordinate is divided into equal parts, and a micro area is set. Then, the frequency distribution of the absolute value of the inclination-angle of the micro area | region with respect to the micro area | region which divided | segmented the Y coordinate by the same method as mentioned above is calculated. The frequency / (cos of inclination angle) of each inclination angle of the calculated frequency distribution is calculated | required. Next, the total of the frequency / [cos of inclination angle] is obtained. Next, for each angle of inclination, {frequency / [cos of inclination angle]} / total is obtained. This value becomes the frequency distribution when the cross-sectional shape is equally divided to set the micro area.

The average inclination angle was measured using a 1 micrometer R, 55 ° cone diamond needle (010-2528) as a stylus with a stylus type surface roughness gauge (Surf Komu 570A type manufactured by Tokyo Regular Co., Ltd.) at a driving speed of 0.03 mm / sec. . The measurement length was 2 mm. After correcting the inclination of the average line of the extraction curve, the center line average value of the curve obtained by differentiating the curve was calculated according to the above formulas (1) and (2).

The distance from the stainless steel plate to the discharge nozzle was determined using glass beads (J220, manufactured by Bottaz Varinity Co., Ltd.) having a particle diameter of 106 μm or less. 32 cm, discharge nozzle 0.15 MPa, the nozzle is run at a moving speed of 8.0 cm / s in the X-axis direction, and the front blasting process of the stainless steel plate is carried out while moving the stainless steel plate sequentially by 10 mm in the Y-axis direction. It was roughening. The average inclination angle θa of the roughened portion was 1.0 °.

Subsequently, the shielding plate (having an opening having a radius of 45 mm) shown in FIG. 70 was disposed at a height of 7 cm from the front blasted stainless steel plate, and the nozzle movement speed was adjusted to 6.0 cm / s as described above. A second blast treatment was performed. The average inclination angle θa of the treated portion was 1.8 °. Next, the shielding plate (having an opening of a radius of 17 mm) shown in FIG. 71 was placed at a height of 7 cm with the second blasted stainless steel plate, and the third blasting process was performed in the same manner as the second blasting process. The average inclination angle θa of the treated portion was 2.5 °. In addition, the shielding plate (having two triangular openings) shown in FIG. 72 was arrange | positioned at the height of 2 cm from the stainless steel plate which carried out the 4th blasting process, and the alumina particle (made by Fujimi Incorporated Company) of an average particle diameter of 30 micrometers A400) was used, except that the nozzle movement speed was 1.5 cm / s and the discharge pressure was 0.6 MPa, the fourth blast treatment was carried out in the same manner as the second blast treatment to obtain a first mold.

On the other hand, the effective area 51mm x 71mm and 34mm thickness quenched steel which grind | polishing grind | polish performed the nickel plating of thickness 0.2mm, and mirror-mirror processing was carried out, and the lens row of pitch 50micrometer was made to the side of 71mm length on the surface. A symmetrical lens pattern that spoke in parallel was formed by cutting. Subsequently, the area | region from the side of 51 mm of length of this metal mold | die to 3.5 mm is masked with an adhesive tape, and nozzle movement speed is 3.8 cm / s using glass beads (J400 made by Bottaz Varinity) of 63 micrometers or less in particle diameters, Except having made discharge pressure into 0.2 Mpa, the blast process was performed like the 2nd blast process, and the 2nd metal mold | die which roughened the shape transfer surface of the lens pattern partially was obtained.

In addition, alumina particles (A400 manufactured by Fujimi Incorporated) having an average particle diameter of 30 µm were used for an quenched steel having an effective area of 0.85 mm x 51 mm and a thickness of 34 mm, and the nozzle height was 16 cm and the nozzle movement speed was used. Except having made 5.0 cm / s and discharge pressure 0.08 Mpa, the blast process was performed like the 2nd blast process, and the 3rd metal mold | die was obtained.

Injection molding is performed using the obtained first mold as the mold for the light exit surface, the second mold as the mold for the back surface, and the third mold as the mold for the light incident end face, and in a rectangle of short side 51 mm and long side 71 mm, The wedge shape varies from 0.85 mm (light incident end face side end) to 0.6 mm (opposite end) along a long side, and one main surface is a light exit surface in which a high light diffusion region is formed near the light incident end face. The light guide made of transparent acrylic resin in which the main surface of the side is a lens row formation surface was produced. In the area | region from the light incidence end surface to 3.5 mm of the lens row formation surface of the obtained transparent acrylic resin light guide body, it grind | polished until sand-ray lens disappears and buff polishing was performed, and it was mirror-mirrored.

An array having three LEDs (LNR 03703: Kagoshima Matsushita Electronics Co., Ltd .: LED spacing: 15.5 mm) was disposed so as to face a short side end face (light incidence end face) having a thickness of 0.85 mm. A prism sheet (M168YS manufactured by Mitsubishi Rayon Co., Ltd.), in which a light scattering reflection sheet (75W05 manufactured by Reco Corporation) is disposed on the lens row forming surface side of the light guide, and a plurality of prism rows having a pitch of 18 µm are arranged in parallel on the light emitting surface side. ) Was arranged such that the prism thermal forming surfaces faced each other to produce a surface light source device.

This surface light source device is used in combination with a liquid crystal display element to constitute a liquid crystal display device having a dimension of an effective light emitting area of 46 mm x 61 mm, and a distance from the light guide cross section to the effective light emitting area of 6.25 mm. The cross-sectional shape of the lens column formation surface of the obtained light guide was as follows.

(Area A: area up to 3.5 mm from the light incident cross section)

Mirror

(Area B: Area other than Area A)

Outward convex curve

Frequency distribution of absolute tilt angle:

30 ° or more and 50 ° or less ---- 26%

Bone inclination angle: 12 °

All LEDs were turned on and the light source device was made to emit light, and the luminance unevenness of the effective light emission area was determined. 73, dark root as shown in FIG. 74, root due to overlapping distribution of light sources as shown in FIG. 75, root as shown in FIG. 76, LED None of the anterior dark side was observed.

Comparative Example 19

A surface light source device was produced in the same manner as in Example 50 except that the lens heat-forming surface of the obtained transparent acrylic resin light guide was not polished. The cross-sectional shape of the lens column formation surface of the obtained light guide was as follows.

(Area A: area up to 3.5 mm from the light incident cross section)

Outward convex curve

Frequency distribution of absolute tilt angle:

20 ° or more and 50 ° or less ---- 67%

25 ° or more and 50 ° or less ---- 51%

30 ° or more and 50 ° or less ---- 39%

35 ° or more and 50 ° or less ---- 26%

40 ° or more and 50 ° or less ---- 8%

15 ° or less ------------ 33%

35 ° or more and 60 ° or less ---- 26%

40 ° or more and 60 ° or less ---- 8%

Maximum value of the ratio of α ° to α ° + 10 °: 31% (α ° = 31 °)

Bone inclination angle: 31 °

(Area B: Area other than Area A)

Outward convex curve

Frequency distribution of absolute tilt angle:

30 ° or more and 50 ° or less ---- 26%

Bone inclination angle: 12 °

All LEDs were turned on and the surface light source device was made to emit light, and the luminance unevenness of the effective light emission area was determined. The list by which the superficial luminance unevenness of the bright root shape in the oblique direction of the light radiate | emitted from each point shape light source as shown in FIG. 76 overlapped was observed clearly.

Claims (23)

In the light guide body which guides the light which generate | occur | produces the light emitted from a primary light source, and has the light incident cross section which light injected from the said primary light source enters, the light exit surface which the light guided out, and the back surface opposite to the said light exit surface, On either of the light exit surface and the rear surface, the first light absorption band and the second light absorption band extending along the light incident end face are arranged in parallel in this order from the side closer to the light incident end face, The width of the first light absorption band is 50㎛ to 800㎛, The side edge close to the light incident cross section of the first light absorption band has a distance from the light incident cross section of 0 μm to 300 μm, The side edge close to the light incident cross section of the second light absorption band is located 500 μm to 300 μm away from the light incident cross section, An edge portion forming a boundary between the light exit surface and the light incident end surface is formed along the light incident end surface as a protrusion raised to another area of the light exit surface, and the full width at half maximum height of the protrusion is formed. Characterized in that 1㎛ 50㎛ Light guide for surface light source device. The method of claim 1, The visible light transmittance of the second light absorption band is higher than the visible light transmittance of the first light absorption band. Light guide for surface light source device. delete In the method for manufacturing the light guide for a surface light source device according to claim 1, By ejecting ink from a plurality of nozzles by the inkjet method, ink dots independent or partially continuous with each other are formed in a region close to the light incident end surface of the light exit surface of the light guide body, Next, by leveling the ink dots and joining adjacent ones, a continuous ink layer is formed over the entire area close to the light incident end surface, Thereafter, the first light absorption band and / or the second light absorption band are formed by curing the ink layer. The manufacturing method of the light guide for surface light source devices. The method of claim 4, wherein The light incidence end face is formed by cutting the light incident end face corresponding portion of the light guide material to form the light incidence end face, and then the first light absorption band is formed. The manufacturing method of the light guide for surface light source devices. The light guide for surface light source devices of Claim 1, the said primary light source arrange | positioned adjacent to the said light incident end surface of the said light guide, and the optical deflection element arrange | positioned adjacent to the light exit surface of the said light guide body, The light deflecting element has a light incidence surface positioned opposite to the light exit surface of the light guide and an outgoing surface on the opposite side thereof, The light incident surface of the light deflection element is provided with a plurality of prism rows extending in a direction parallel to the light incident end surface of the light guide and parallel to each other. Cotton light source device. The method of claim 6, The light diffusing element is arranged adjacent to the light exit surface of the light deflecting element, The light diffusing element includes a dot pattern portion in which a light absorption dot pattern is formed in a width region including a position of 2 mm to a position of 4 mm from a light incident end surface of the light guide, The dot pattern portion is formed by dispersing a dot-shaped light absorbing ceramic material having a diameter of 30 µm to 70 µm. Cotton light source device. In the light guide body which guides the light which generate | occur | produces the light emitted from a primary light source, and which has the light incident cross section which light injected from the said primary light source enters, the light exit surface which the light guided out, and the back surface opposite to the said light exit surface, A light absorption band having a width of 50 μm to 1000 μm extending along the light incident cross section is formed on the rear surface, and a side edge close to the light incident cross section of the light absorption band has a distance from 0 μm to 300. Μm, An edge portion forming a boundary between the back surface and the light incident cross section is formed along the light incident cross section as a protruding portion protruding from another area of the back surface, The height half width of the protrusion is characterized in that 1㎛ to 50㎛ Light guide for surface light source device. delete The method of claim 8, On the rear surface, a prism row forming surface region having a plurality of prism rows arranged in a direction perpendicular to the light incident end surface and arranged in parallel with each other is formed, The rear surface is formed with a flat surface region extending along the light incident cross section, Part or all of the light absorption band is located at part or all of the flat surface region Light guide for surface light source device. The method of claim 8, The light absorption band is formed so that the visible light transmittance is higher on the side edges farther than the side edges close to the light incident cross section. Light guide for surface light source device. The method of claim 8, The width of the light absorption band is 50㎛ to 800㎛, On the rear surface, a second light absorption band extending along the light incidence cross section at a position far from the light incidence cross section than the light absorption band is formed. The side edge close to the light incident end face of the second light absorption band is positioned 500 占 퐉 to 3000 占 퐉 away from the light incident end face. Light guide for surface light source device. The method of claim 12, The visible light transmittance of the second light absorption band is higher than the visible light transmittance of the light absorption band. Light guide for surface light source device. In the light guide body which guides the light which generate | occur | produces the light emitted from a primary light source, and has the light incident cross section which light injected from the said primary light source enters, the light exit surface which the light guided out, and the back surface opposite to the said light exit surface, On the light exit surface or the back surface, there is formed a prism row forming surface region having a plurality of prism rows extending in a direction orthogonal to the light incident end surface and arranged in parallel with each other. A flat surface region extending along the light incident cross section is formed on the light exit surface or the rear surface on which the prism row forming surface region is formed, A light absorption band having a width of 50 μm to 1000 μm extending along the light incident cross section is formed in part or all of the flat surface area. An edge portion forming a boundary between the light incident end surface and the light exit surface or the back surface is provided with a protruding portion that is raised relative to the light exit surface or another region of the back surface. Light guide for surface light source device. The method for manufacturing the light guide for a surface light source device according to claim 8 or 14, The light incidence end face is formed by cutting the light incident end face corresponding portion of the light guide material to form the light incidence end face, and then the light absorption band is formed. The manufacturing method of the light guide for surface light source devices. The method of claim 15, By ejecting ink from a plurality of nozzles by the inkjet method, ink dots independent or partially continuous with each other are formed in a region close to the light incident end surface of the rear surface of the light guide body, Next, by leveling the ink dots and joining adjacent ones to each other, a continuous ink layer is formed over the entire area close to the light incident end surface. Thereafter, the light absorption band is formed by curing the ink layer. The manufacturing method of the light guide for surface light source devices. The light guide for surface light source devices of Claim 8 or 14, the said primary light source arrange | positioned adjacent to the said light incident end surface of the said light guide, and the optical deflection element arrange | positioned adjacent to the light exit surface of the said light guide. Equipped with The light deflecting element has a light incidence surface positioned opposite to the light exit surface of the light guide and an outgoing surface on the opposite side thereof, The light incident surface of the light deflection element is provided with a plurality of prism rows extending in a direction parallel to the light incident end surface of the light guide and parallel to each other. Cotton light source device. The method of claim 17, The light diffusing element is arranged adjacent to the light exit surface of the light deflecting element, The light diffusing element includes a dot pattern portion in which a light absorption dot pattern is formed in a width region including a position of 2 mm to a position of 4 mm from a light incident end surface of the light guide, The dot pattern portion is formed by dispersing a dot-shaped light absorbing ceramic material having a diameter of 30 μm to 70 μm. Cotton light source device. In the plate-shaped light guide body which guides the light which generate | occur | produces the light emitted from a primary light source, and also has the light incidence cross section into which the light emitted from the said primary light source enters, and the light exit surface from which the light guided out is emitted, On one of the light emitting surface and the back surface on the opposite side thereof, a plurality of uneven structure rows extending along the direction of directivity of light incident on the light guide body in the surface along the light emitting surface and arranged in parallel with each other Formed, A band-like flat portion extending along the light incident cross section is formed in part or all of the area from the region in contact with the light incident cross section of the uneven structure thermoforming surface to the effective light emitting region, In the vicinity of the primary light source of the concave-convex structure row, the cross-sectional shape orthogonal to the extending direction of the plurality of concave-convex structure rows is the angle of inclination between the tangent in each micro region and the concave-convex structure row forming surface. The absolute value of the angular component of 20 ° or more and 50 ° or less is characterized in that 10% or more Light guide for surface light source device. The method of claim 19, A light output mechanism is provided on part or all of the light exit surface, the back surface, and the inside of the light guide. Light guide for surface light source device. The method of claim 20, The light output mechanisms extend along a direction roughly formed on at least one of the light exit surface and the rear surface, or a direction orthogonal to the direction of the directivity of light incident on the light guide member or the direction of the directivity of light incident on the light guide member. Characterized by a plurality of parallel rows of lenses Light guide for surface light source device. delete The light guide for surface light source devices of Claim 19, A primary light source disposed adjacent to the light incident cross section of the light guide; It is disposed adjacent to the light exit surface of the light guide, has a light entrance surface facing the light exit surface of the light guide and the light exit surface on the opposite side, parallel to the light incident end surface of the light guide on the light incident surface. And an optical deflecting element extending in one direction and having a plurality of lens rows parallel to each other. Cotton light source device.

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