JP4545673B2 - LIGHTING DEVICE AND DISPLAY DEVICE USING THE SAME - Google Patents

Description

  The present invention has a plurality of linear light sources, a reflecting plate that reflects light from the linear light source, and a light incident surface and / or a light emitting surface that has a concavo-convex shape, from the linear light source and the reflecting plate. The present invention relates to an illuminating device including at least a light control member that refracts and transmits the light of light and a protrusion that holds the light control member, and a display device in which a transmissive display element is provided on the illuminating device.

  In recent years, particularly in the field of illumination and transmissive displays, there has been a demand for high brightness, thinness, and uniform brightness, and a plurality of linear light sources, a reflector provided on the back surface thereof, and light that forms a light emitting surface. A direct illumination device having a configuration in which a diffusion plate is combined is preferably used. Such a direct illumination device has a high effective utilization efficiency of the light beam emitted from the linear light source (the ratio of the light beam emitted from the lamp radiated from the light emitting surface) and can increase the number of linear light sources used. Therefore, the luminance of the light emitting surface can be easily increased. In such a direct illumination device, a light diffusing plate is disposed at a relatively short distance right above the linear light source, and therefore contains a large amount of light diffusing fine particles for the purpose of erasing the lamp image of the linear light source. The light diffusing plate was usually used. However, although a light diffusion plate containing a large amount of light diffusing fine particles has good diffusion characteristics, there is a problem in that light loss and light reflectance due to the light diffusing fine particles are high, and light use efficiency is reduced. It was. Therefore, in recent years, a light control member using a prism lens or the like has been developed as a method for erasing a lamp image without containing light diffusing fine particles (see Patent Document 1).

  Moreover, since the distance between the linear light source and the light diffusing plate becomes shorter when the lighting device is made thin, and the weight of the light diffusing plate becomes larger when the lighting device is enlarged, the light diffusing plate becomes a linear light source. There was a problem of deformation due to heat and dead weight. Therefore, as a method of suppressing warpage or deflection of the light diffusion plate used in the illumination device in the direction of the linear light source, for example, a protrusion on the reflection plate is used for the purpose of holding the light diffusion plate and suppressing the deflection of the light diffusion plate. An illuminating device provided with was used. In this case, since the reflectance by the light diffusing plate or the like is high, generally, the projection is projected on the light diffusing plate by using the same material or the same color as the surrounding reflecting plate which is opaque. It was preventing. On the other hand, when a specially shaped protrusion such as a protrusion wall is used, a transparent material may be used (see Patent Document 2).

JP 2002-352611 A (Claims, FIG. 1, etc.) Japanese Patent Laid-Open No. 5-119316 (Claims, FIG. 3, etc.)

  However, when a light control member with high light utilization efficiency and high light transmittance is used for the purpose of improving the brightness of the lighting device, the shadow of the protrusion provided on the reflector can be seen through the light control member. There was a case where the problem of end. Further, when a light control member using a prism or the like is used as the optical surface pattern, a problem that the shadow of the protrusion appears double is newly generated. In recent years, there has been a demand for higher brightness for the above-mentioned lighting device, and therefore there is a further demand for an improvement in light transmittance for a light control member used in the lighting device. There is also a need for improvement.

  Therefore, the present invention provides a lighting device having a plurality of linear light sources and a reflecting plate that reflects light from the linear light sources, and the light transmittance of the light control member used for the purpose of erasing the image of the linear light sources. Even if it is high, the projection used for the purpose of holding the light control member is made of a material or shape that does not substantially project a shadow on the light control member, so that it is bright and has high surface uniformity. The purpose is to provide. Another object of the present invention is to provide a display device in which a transmissive display element is further provided in the illumination device.

As a result of intensive studies on the above problems, the present inventors have found that the problem can be solved by devising the shape of the protrusions used in the direct illumination device or the configuration of the light control member, and completed the present invention.
That is, the present invention has a plurality of linear light sources, a reflecting plate that reflects light from the linear light sources, and a light incident surface and / or a light exit surface having an uneven shape, and the linear light sources and the reflections In an illumination device comprising at least a light control member that refracts and transmits light from a plate and a protrusion that holds the light control member, the protrusion is made of a light-transmitting material, and the horizontal cross section of the protrusion has a circular shape. In this illumination device, the diameter of the tip of the protrusion that contacts the light control member is 1 mm or less. In the present specification, a cross section obtained by cutting the protrusion along a plane parallel to the main surface of the light control member is referred to as a “horizontal cross section of the protrusion”.

The invention according to claim 1 includes a plurality of linear light sources, a reflecting plate that reflects light from the linear light source, and a light control member that refracts and transmits light from the linear light source and the reflecting plate. And a projection that holds at least the light control member, the reflector, the linear light source, and the light control member are arranged in this order from the light incident side to the light emission side, and the projection is It is made of a light-transmitting material, and the projection has a circular horizontal cross section, and the diameter of the tip of the projection in contact with the light control member is 1 mm or less, and the light control member mainly receives light, and mainly emits light. A light exit surface, the light entrance surface and / or the light exit surface has a concavo-convex shape, and the distance between an arbitrary linear light source M and another linear light source N nearest to it is D, When the distance between the linear light source M and the light control member is H In the alpha = Tan at any point with respect to the normal direction of the incident surface of the incident surface ^{-1 {(D / 2) /} H} angle total light transmittance of the incident light is 50% or more And the total light transmittance is 1.05 to 3 times the total light transmittance of light when light enters the point on the incident surface from the normal direction. Device.

  According to the second aspect of the present invention, 10 to 50% of the light incident at an angle α with respect to the normal direction of the incident surface of the light control member has an angle formed with the normal direction of the output surface of −15 ° to +15. The illumination device according to claim 1, wherein the illumination device emits light in a range of °.

According to a third aspect of the present invention, the light control member has a flat entrance surface, the exit surface is formed with the concavo-convex shape, is orthogonal to the exit surface, and includes the top of the concavo-convex shape. The contour line in the light exit portion of the cross section in one direction is such that when the refractive index of the light control member is n, the slope θ2 of the contour line is 0 ≦ | Sin ⁻¹ (n · sin (θ2−Sin ⁻¹ ((1 / n) · sin α))) − θ2 | ≦ (π / 12) is satisfied, and the slope θ2 includes a region X that is less than Sin ⁻¹ (1 / n). The ratio of the length x of the direction component parallel to the exit surface of the region X and the length P of the direction component parallel to the exit surface of the entire contour line is 0.15 to 0.80. The illumination device according to claim 1, wherein:

  According to a fourth aspect of the present invention, the light control member has a contour line in a light emission portion of a cross section along at least a predetermined direction that is orthogonal to the emission surface and includes the top of the uneven shape. 4. The method according to claim 1, comprising two substantially straight lines having an acute angle θ at which the extension lines intersect, and a convex curve connecting the ends of the two substantially straight lines. It is an illuminating device of description.

  According to a fifth aspect of the present invention, the line includes a plurality of concave and convex shapes formed on the light exit surface of the light control member, perpendicular to the light exit surface, and including the top of the corrugated shape on the light exit surface. 5. The illumination according to claim 1, wherein a ridge line in a light emitting portion sectioned in a direction parallel to the linear light source is a straight line extending in a direction parallel to the linear light source. Device.

  The invention described in claim 6 is a display device characterized in that a transmissive display element is provided on the illumination device according to any one of claims 1 to 5.

According to the configuration of the first aspect, since the protrusion is made of a light-transmitting material, the horizontal cross section of the protrusion is circular, and the diameter of the protrusion tip portion in contact with the light control member is 1 mm or less, the light transmittance is high. Even when the light control member having the above is employed, it is possible to provide a lighting device that is difficult to see the shadow of the protrusion and has high brightness. In this case, since the deflection of the light control member can be held by the protrusions as in the conventional case, it is possible to suppress warping and deflection of the light control member.
The total light transmittance of light incident at a predetermined angle α = Tan ⁻¹ {(D / 2) / H} with respect to the normal direction of the incident surface of the light control member is 50% or more, and The total light transmittance is 1.05 to 3 times the total light transmittance in the case of light incident from the normal direction, that is, the total light incident on the position directly above the linear light source. It is appropriately higher than the light transmittance. Therefore, the in-plane distribution of light energy emitted from the light control member is made uniform. Further, preferable optical properties can be obtained at any point on the incident surface.

  According to the structure of Claim 2, in addition to the above effect, the illuminating device with high front luminance preferable as many illuminating devices can be provided.

  According to the configuration of claim 3, in addition to the above effects, it is easy to control the emitted light at an angle in the range of (−π / 12) to (π / 12) with respect to the normal of the emission surface. It is possible to provide a lighting device with high front luminance that is preferable as many lighting devices.

  According to the configuration of the fourth aspect, in addition to the above effects, diffusivity and light exit direction control can be easily achieved by performing different light control on the concavo-convex linear portion and the curved portion.

  According to the configuration of claim 5, in addition to the above effects, the luminance unevenness in the direction perpendicular to the linear light source in which the most noticeable unevenness of the linear light source occurs is a bowl-shaped uneven shape parallel to the linear light source. Can be solved efficiently.

  According to the configuration of the sixth aspect, since the transmissive display element such as a liquid crystal panel is provided on the illuminating device, the light rays that are efficiently condensed and diffused by the light control member are transmitted through the transmissive display element. As a result, it is possible to easily obtain a display device that has a simple configuration, does not require adjustment of the light source position, can eliminate the lamp image, and has excellent brightness on the exit surface. Here, the display device refers to a display module in which a lighting device and a display element are combined, and a device having at least a display function such as a television or a personal computer monitor using the display module.

Hereinafter, the present invention will be described in detail.
The illuminating device of the present invention has a plurality of linear light sources, a reflector that reflects light from the linear light sources, a light incident surface and / or a light exit surface having an uneven shape, and the linear light source and the light source An illumination device comprising at least a light control member that refracts and reflects light from a reflector, and a protrusion that holds the light control member, the protrusion made of a light-transmitting material, and the horizontal cross section of the protrusion It is circular, and the diameter of the tip of the protrusion in contact with the light control member is 1 mm or less.

Next, the structure and function of a lighting device according to an embodiment of the present invention will be described with reference to the drawings.
First, FIG. 1 shows a cross-sectional view of a backlight illumination device for a liquid crystal display device which is an embodiment of the present invention. In the embodiment shown in FIG. 1, the backlight illumination device (backlight module) A is composed of a linear light source C such as a cold cathode tube, a light control member B, a reflector D, and a protrusion E.
Next, FIG. 2 and FIG. 3 are enlarged views of specific embodiments corresponding to the vicinity where the protrusions of FIG. 1 are arranged, and FIG. 4 shows the backlight device with the light control member removed from above. FIG. 5 and FIG. 5 schematically show partial enlarged views of the backlight device with the light control member of a preferred embodiment attached as seen from obliquely above.

  As shown in the figure, the backlight illumination device shown in the above embodiment of the present invention includes a linear light source C such as a cold cathode tube, a light control member B, a reflecting plate D, and a protrusion E. E is attached as a means for fixing the light control member B, for example, as shown in FIG. 4, at the center in the vertical direction of the backlight illumination device and symmetrically in the horizontal direction. However, the position and number of the protrusions may be appropriately changed depending on the size of the backlight illumination device, the degree of deflection of the light control member, and the like, and a plurality of protrusions may be provided. In the following description, as shown in FIG. 4, an example will be described in which a total of two are attached to the center of the backlight illuminating device in the longitudinal direction and one in the lateral direction symmetrically.

The light control member B can be used as long as it has a concavo-convex shape on the light incident surface and / or light output surface, and a small amount of light diffusing fine particles may be mixed as described later. When the distance between the linear light source M and another linear light source N nearest to the linear light source M is D and the distance between the linear light source M and the light control member is H, any distance on the incident surface is set. The total light transmittance of light incident on the point at an angle of α = Tan ⁻¹ {(D / 2) / H} with respect to the normal direction of the incident surface is 50% or more, and the total light transmission Preferably, the rate is 1.05 to 3 times the total light transmittance of light when light enters the point on the incident surface from the normal direction. 2, 3, 5, 6, and 7, a flat surface is formed on the light incident surface of the light control member B, and an angle formed by the extended lines of the two substantially straight lines 10 in FIG. 8 on the light exit surface. Cylindrical projections of θ = 50 °, P1 = 260 μm, and A1 = 182 μm are formed, the light incident surface faces the linear light source, and the longitudinal direction of the cold cathode tube that is a linear light source and the prism ridge line of the light exit surface It is arranged in a direction that substantially matches. Further, the protrusion E may be integrated with the reflecting plate D and an adhesive tape as shown in FIG. 2, or may be embedded in the reflecting plate as shown in FIG.

  Next, the cause of the shadow on the light control member caused by the protrusion E will be described. In the light control member as shown in the preferred embodiment of the present invention, as shown in FIGS. 6 and 7, the direction of the light from the linear light source is controlled using the principle of light refraction and reflection, and a bright surface line is obtained. A light source. At this time, if the light beam from the linear light source is blocked by the projection made of an opaque material, the light beam cannot reach the light control member as shown in FIG. 9, and as a result, the light exit surface of the light control member When viewed from above, the shadow of the protrusion can be seen. In particular, when a light control member that forms a concavo-convex shape on at least one surface in the present invention is used, there may be a problem that the shadow of a projection made of an opaque material appears double.

  On the other hand, the light diffusing plate containing a large amount of light diffusing fine particles used in place of the conventional light control member has a strong light scattering action, and thus there is a light shielding portion by a protrusion on the incident surface of the light diffusing plate. Even in this case, the shadow of the protrusion was hardly recognized on the light diffusing plate exit surface by the scattered light from the other light incident portions. The degree of the light scattering action that makes it possible to recognize the shadow of the protrusion is also affected by the characteristics of the light diffusing fine particles, but generally depends on the concentration of the light diffusing fine particles, and less than 1 part by weight of the light diffusing fine particles. In the case of the light diffusing plate including, the shadow of the protrusion is recognized.

  For this reason, the projection used in the lighting device of the present invention needs to have a shape or material that does not project the shadow even on the light control member having a light diffusing fine particle content of less than 1 part by mass. Specific preferred shapes and materials of the protrusions will be described below.

The horizontal cross-sectional shape of the protrusion used in the lighting device of the present invention is important to be a circle, but it is not necessary to be a circle in a strict sense, and includes a case where it is substantially a circle. For example, an ellipse in which the ratio of the length of the short axis to the length of the long axis is 0.8 or more, or a regular polygon having a regular hexagon or more can be regarded as a circle in the present invention, but is not limited to these shapes. Needless to say.
In the lighting device which is one embodiment of the present invention, as shown in FIGS. 6 and 7, the light from the linear light source travels by being directly refracted and reflected and reflected by the light control member. For this reason, when the horizontal cross section of the projection has a shape having a so-called edge such as a quadrangle, the traveling direction of the light abruptly changes on both sides of the edge, so that the projection shadow easily occurs on the exit surface of the light control member. On the other hand, when the horizontal cross section of the protrusion is a relatively flat elliptical shape, the spreading state of the light passing through the protrusion from the linear light source is greatly different between the major axis direction and the minor axis direction of the ellipse. Depending on the direction, the shadow of the protrusion is likely to occur. That is, it is preferable to make the horizontal cross-sectional shape of the protrusions substantially circular, since it is difficult to recognize the shadows of the protrusions even when observed from all directions.

  In addition, it is important that the protrusion used in the lighting device of the present invention is formed of a light transmissive material. The material for forming the protrusion is preferably formed of a transparent material, and if it is so-called transparent, either a thermoplastic resin or a thermosetting resin is preferably used. Specific examples thereof include (meth) acrylic resins, (meth) acryl styrene copolymer resins, styrene resins, aromatic vinyl resins, olefin resins, ethylene vinyl acetate copolymer resins, vinyl chloride resins, Examples thereof include vinyl ester resins, polycarbonates, fluorine resins, urethane resins, silicone resins, amide resins, imide resins, polyester resins, epoxy resins, phenol resins, urea resins, melamine resins, and the like. When the protrusion is formed of an opaque material, a shadow is projected on the light control member, which is not preferable. In addition, the light transmittance of the light transmissive material that does not generate a shadow is preferably 60% or more, and more preferably 80% or more.

  And as a shape of the projection used for the lighting device of the present invention, a cross section is substantially circular, and a diameter of about 1 to 10 mm, preferably about 1 to 6 mm, is used to hold the light control member. It is important that the diameter of the tip of the protrusion contacting the light control member is 1 mm or less, preferably in the range of 0.1 to 0.8 mm, more preferably in the range of 0.1 to 0.5 mm. preferable. When the prism is formed on the light incident surface side of the light control member, it is preferable to hold the light control member at least twice the prism pitch, and the diameter of the tip portion is in the range of 0.1 to 1 mm. Preferably, it is in the range of 0.1 to 0.8 mm, more preferably in the range of 0.1 to 0.5 mm. Since the light from the linear light source is generally diffused light, when considering the optical path of the light ray that becomes a shadow, the shadow of the protrusion becomes thin by the action of the diffused light. However, since the light control member and the protrusion are in contact with each other, there is almost no light diffusing action, so that the shadow of the protrusion can be seen as it is. Therefore, it can be said that the smaller the contact point between the protrusion and the light control member, the better. In addition, the tip of the protrusion is not limited to a flat surface, and has a concavo-convex shape as long as it does not interfere with the contact between the protrusion and the protrusion formed on the light incident surface and / or the light exit surface. May be.

  As an arrangement form of the protrusions, other shapes or structures may be used as long as they are not projected as a shadow on the other light control member B in the form arranged on the reflector D as shown in FIG. . For example, as shown in FIG. 3, it may be embedded in the reflecting plate D, or the linear light source C and the light control member B may be supported by one protrusion E.

Further, as a light control member used in the illumination device of the present invention, the distance between an arbitrary linear light source M and another linear light source N nearest to the linear light source M is D, the linear light source M and the light control. When the distance from the member is H, the light incident on an arbitrary point on the incident surface at an angle of α = Tan ⁻¹ {(D / 2) / H} with respect to the normal direction of the incident surface. The total light transmittance is 50% or more, and the total light transmittance is 1.05 times to 3 times the total light transmittance of light when light is incident on a point on the incident surface from the normal direction. Those that are doubled are preferred. As such a light control member, as shown in FIGS. 5, 6, and 7, a flat surface is provided on the light incident surface, and an uneven shape is provided on the light emitting surface. Due to the uneven shape of the flat entrance surface and exit surface, a portion directly above the linear light source, that is, a part of the light incident perpendicularly to the light control member is refracted and transmitted, but a part is transmitted by total reflection. Without returning to the linear light source side. Furthermore, since the light incident on the linear light source is also emitted almost perpendicularly to the light control member, the light emitted from the light control member is uniformly distributed in the plane, and the illumination device is expensive. Brightness can be obtained.

  As shown in FIG. 5, the reflector, the linear light source, and the light control member are arranged in this order from the light incident side to the light emission side, and the light control member has a plurality of regular uneven shapes: emission surface It has irregularities. In this way, in the illumination device in which a plurality of linear light sources are arranged between the reflector and the light control member, as shown in FIG. 10, to the virtual surface corresponding to the incident surface of the light control member. The incident light has different light incident energies between the portion directly above each linear light source and the portion between adjacent linear light sources.

  That is, in the region directly above each linear light source position, the incident energy is large because it is close to the linear light source. On the other hand, the non-directly above region facing the position between the plurality of linear light sources (slantly above each linear light source) In (part), since it is away from the linear light source, the incident energy is small.

  Further, as shown in FIG. 11, in the angular distribution diagram of the incident energy with respect to the virtual surface, that is, the luminance distribution diagram with respect to the incident angle, the luminance of the light beam incident in the direction perpendicular to the virtual surface shows the maximum value. On the other hand, as shown in FIG. 12, in the angular distribution diagram of the emission energy with respect to the virtual surface, that is, the luminance distribution diagram with respect to the emission angle, the luminance of the light ray incident in an oblique direction with respect to the virtual surface, The brightness of the light beam in the vicinity of the center position between the light sources shows the maximum value.

  In the illuminating device according to the present invention, as shown in FIG. 13, the distance between an arbitrary linear light source M and another linear light source N located nearest to the linear light source M is D, the line When the distance between the light source M and the light control member is H, the ratio of light incident on the incident surface from the exit surface of the light control member at any point on the incident surface of the light control member The total light transmittance is in the range of 50% to 100%, and has the following relationship.

That is, when light is incident at an angle of α = Tan ⁻¹ {(D / 2) / H} with respect to the normal direction of the incident surface, the total light transmittance R1 of the light is relative to the incident surface. The total light transmittance R2 of the light when the light is incident in the vertical direction is 1.05 to 3.00 times. The ratio R1 / R2 of the total light transmittance is more preferably 1.05 to 2.00 times from the viewpoint of light utilization efficiency.

  Here, when measuring the total light transmittance described above, the width of the parallel light beam to the measurement object is, for example, a concavo-convex shape on the surface of the light control member. In order to reflect the feature of the uneven shape on the total light transmittance, it is necessary that the light is incident on a wide region at least larger than the pitch of the uneven portion.

  FIG. 14 shows a method for measuring the total light transmittance of parallel light incident on a measurement object having a flat incident surface at an incident angle β. As shown in the figure, the object to be measured is placed so as to close the opening of the integrating sphere, and the collimated light collimated with the laser beam or the lens is converted into β with respect to the normal direction of the object to be measured. Incident at an angle of.

  Thus, the light transmitted through the measurement object is diffusely reflected in the integrating sphere, and the reflected energy is measured by a detector (not shown) represented by a photomultiplier. Here, the measurement object is installed as shown in the figure, and the output of the detector when parallel light is incident at an angle β is V (β), and the output of the detector when the measurement object is not installed is Assuming V0, the total light transmittance at an angle β is obtained by V (β) / V0.

  As shown in FIG. 13, the angle α indicates that the light emitted from the linear light source M or the linear light source N is incident on the light control member at a position just above the midpoint between the linear light source M and the linear light source N. This corresponds to the incident angle of the light beam. With respect to the total light transmittance, the light when incident on the light control member at an incident angle α (≠ 0) from an oblique direction, rather than the total light transmittance R2 of the light when incident on the light control member from the vertical direction. The total light transmittance R1 is higher. For this reason, the emitted light energy of the light control member can be made uniform as a whole in the portion directly above each of the linear light sources M and N and the portion between the linear light source M and the linear light source N.

  Furthermore, since the total light transmittance of the light control member depends only on the incident angle and does not depend on the incident position with respect to the light control member, it is not necessary to adjust the positions of the plurality of linear light sources and the light control member. That is, it is not necessary to strictly set the position of the light control member in the in-plane direction when the lighting device is assembled. Therefore, after the light control member of the present invention is manufactured with a large area, it is possible to use a light control member cut out from an arbitrary position according to a required dimension, so that the productivity of the lighting device can be remarkably improved.

  Hereinafter, an example of specific means for adjusting the total light transmittance when light enters the light control member from the vertical direction and the oblique direction will be described. First, as a first example of the specific means, as shown in FIG. 5, there may be mentioned an aspect in which a plurality of uneven shapes are provided on the exit surface of the light control member. FIG. 8 shows a suitable cross-sectional shape in which the uneven shape 9 is formed in a stripe shape.

  The concavo-convex cross-sectional shape is composed of a contour line in a case where the concavo-convex cross-section is orthogonal to the emission surface of the light control member and is crossed along at least one predetermined direction including the top of the concavo-convex shape. The outline is composed of two substantially straight lines (parts) having an acute angle θ at which the extension lines intersect, and a curve (part) connecting each end of the two substantially straight lines (parts), and The top of the contour line is a convex curve.

  Here, the predetermined one direction means a direction parallel to the direction from the linear light source M to the linear light source N. Further, the radius of curvature of the curve constituting the top of the contour line may be infinite, that is, a straight line.

FIG. 15 and FIG. 16 show the behavior of the light beam when the concavo-convex shape 2 having a substantially elliptical cross section is formed on the emission surface. By configuring the concavo-convex shape in a substantially elliptical shape, the absolute value of the inclination of the concavo-convex shape skirt 11 is 0 ≦ | Sin ⁻¹ (n · sin (θ 2 −Sin ⁻¹ ((1 / n) · sin α))). −θ2 | ≦ (π / 12) that satisfies θ2 or less.

In FIG. 18, oblique incident light incident at an angle α with respect to the normal can be emitted from the light control member B in a substantially front direction by refraction at the concavo-convex bottom.

This is due to the following reason.
As shown in FIG. 10, when the slope of the concavo-convex shape is γ, the incident angle to the light control member is φ1, and the refractive index of the light control member is n, the light is transmitted from one skirt of the concavo-convex shape of the light control member. The angle φ5 of the light with respect to the normal direction of the light control member can be obtained as follows.
φ ₂ = Sin ⁻¹ {(sin φ ₁ ) / n}
φ ₃ = γ−φ ₂
φ ₄ = Sin ⁻¹ (n × sin φ ₃ )
φ ₅ = φ ₄ −γ
That is, φ ₅ = Sin ⁻¹ (n · sin (γ−Sin ⁻¹ ((1 / n) · sin φ ₁ ))) − γ
From the gist of the present invention, it is preferable that the light emission direction is the front direction. Therefore, when φ ₁ = α, it is desirable that −15 ° ≦ φ ₅ ≦ 15 °. Further, it is more desirable that −10 ° ≦ φ ₅ ≦ 10 °. Furthermore, it is preferable to select γ so that −5 ° ≦ φ ₅ ≦ 5 °.

  For example, assuming that the distance D between the linear light sources is 33 mm, the shortest distance H from the center of the linear light source to the light control member is 15 mm, and the refractive index n of the light control member is 1.54, 52 ° ≦ γ ≦ 69 ° (42 It is desirable that ° ≦ θ2 ≦ 76 °). Further, it is more preferable that 57 ° ≦ γ ≦ 68 ° (44 ° ≦ θ2 ≦ 66 °). Furthermore, it is preferable to select γ so that 62 ° ≦ γ ≦ 67 ° (46 ° ≦ θ2 ≦ 56 °).

The top of the concavo-convex shape has a region X in which the absolute value θ2 of the inclination with respect to the exit surface is less than Sin ⁻¹ (1 / n). As described above, the slope θ2 of the region X can take a plurality of values. Since θ2 continuously changes due to the curved portion, the dispersion direction can be continuously changed, and higher luminance uniformity can be obtained. Desirably, the slope of an arbitrary point on the top of the concavo-convex shape is equal to or less than the absolute value of the slope of the skirt of the concavo-convex shape with respect to the exit surface. This is desirable from the viewpoint of easy molding and easy control of light direction.

  Further, as shown in FIG. 16, a part of the light 14 incident perpendicularly to the light control member B is emitted while being dispersed in the direction, and at the same time, a part of the light incident on the irregular surface returns to the incident side as reflected light 16. As a result, the total light transmittance can be suppressed. Accordingly, it is possible to obtain a lighting device with high luminance uniformity and high luminance.

  The uneven shape can be formed into a three-dimensional shape having two substantially straight cross sections and a cross section curve. The reason for this will be described below. As shown in FIG. 6, the three-dimensional shape of the concavo-convex shape is constituted by two substantially sloped portions (corresponding to a substantially straight section) and a curved surface portion (corresponding to a sectional curve) forming an acute angle θ, thereby providing a light control member. The obliquely incident light obliquely incident on the incident surface of the light can be emitted in a substantially vertical direction (same direction as the substantially vertical direction of the incident surface) from the light emission surface side of the light control member by a refracting action at a substantially straight section. it can.

  Further, as shown in FIG. 8, the light incident perpendicularly to the light control member disperses the emission direction in the curved surface portion of the uneven shape, and at the same time, a part of the light hitting the uneven surface is totally reflected. Since the light is not raised and emitted, the total light transmittance of the light can be suppressed. By reducing the total light transmittance of the vertical light incident perpendicularly to the light control member, it is possible to easily obtain a lighting device with high luminance uniformity and high luminance.

  The ratio A / P of the projected area A of the curved portion to the projected area P of the uneven shape of the light control member is preferably 40 to 80%. For example, the area ratio A1 / P1 in FIG. 8 corresponds to the area ratio A / P. When the area ratio A / P is less than 40%, the light dispersion effect is reduced, and the luminance uniformity is lowered. Further, when the area ratio A / P exceeds 80%, the area of the substantially straight line portion 10 decreases, so that the ratio of the light emitted in the front direction out of the oblique incident light decreases. In-plane brightness uniformity decreases.

  FIG. 17 shows another shape of the concavo-convex shape that can be implemented in the present invention. In this case, a cross-sectional curve (part) is provided in the uneven valley portion. With this cross-sectional curve portion, the light emission direction is dispersed in multiple directions, and an illumination device with high luminance uniformity can be obtained. Furthermore, as means for propagating light in various directions within the light control member to enhance the dispersion effect, means for deflecting parallel light at a plurality of angles on the incident surface of the light control member may be used. Specifically, a concavo-convex structure having random or periodicity is formed on the incident surface of the light control member.

In addition, when the light control member has an uneven surface on the incident surface and the output surface is flat, a convex portion is periodically formed on the incident surface, and includes the top of the convex portion and is orthogonal to the incident surface. The contour line of the cross section in at least one predetermined direction cut by the surface to be cut has two straight portions of the convex portion, and the two straight lines are at the apex portion or at an acute angle θ ′ of an angle (π / 9) or more on the incident side of the apex portion. Crossing is preferable in controlling the total light transmittance. Further, when the refractive index of the light diffusing plate is n between the convex portions of the incident surface and the absolute value of the inclination with respect to the incident surface is 0 ≦ Sin ⁻¹ (n · sin (θ2′−Sin ⁻¹ (1 / N · sin θ2 ′))) ≦≦ (π / 12) by having the region Y having the angle θ2 ′, the light incident on the region Y from the normal direction is efficiently (−π Since the light can be emitted at an angle in the range of / 12) to (π / 12), the front luminance can be increased efficiently. By adjusting the ratio of the region Y to a suitable range, the control of the total light transmittance is further facilitated.

  The height or depth of the concavo-convex shape formed on the emission surface side is desirably 1 μm or more and 500 μm or less. If the thickness exceeds 500 μm, the uneven shape is observed, and the quality is degraded. On the other hand, when the thickness is less than 1 μm, coloring occurs due to the diffraction phenomenon of light, and the quality deteriorates. Further, particularly when using a liquid crystal panel, it is desirable that the average width of the unevenness in the direction parallel to the arrangement direction of the pixels of the liquid crystal is 2/3 or less of the pixel pitch of the liquid crystal. When the average width exceeds 2/3 of the pixel pitch, a moire phenomenon occurs on the surface of the liquid crystal panel, and the image quality of the liquid crystal panel is greatly deteriorated.

  The resin forming the light control member used in the lighting device of the present invention may contain light diffusing fine particles. The light diffusing fine particles contained in the light diffuse the uneven surface image on the incident surface side and / or the exit surface, and can exhibit an effect of eliminating moire. The particle diameter of the light diffusing fine particles is preferably in the range of 1 to 50 μm, preferably less than 1 part by mass with respect to 100 parts by mass of the light transmissive resin as the light transmissive material, and 0.5 mass. It is more preferable to contain less than part.

  The uneven shape on the incident surface side and the uneven shape on the exit surface side of the light control member can be formed by an extrusion molding method, an injection molding method, a 2P molding method using an ultraviolet curable resin, and the like. It is possible to appropriately adopt the shape in consideration of the size of the uneven shape, the required shape, mass productivity, and the like.

Examples of the present invention will be described below, but the present invention is not limited thereto.
(Production of light control member)
A flat surface is formed on the light incident surface facing the linear light source, and a cylindrical shape having an angle θ = 50 °, P1 = 260 μm, and A1 = 182 μm formed by two substantially straight line extensions in FIG. The light control member characterized by the formation of protrusions was produced as follows.

(1) First, a female die having a cylindrical groove with angles θ = 50 °, P1 = 260 μm, and A1 = 182 μm formed by two substantially straight lines in FIG. 8 was produced by cutting. The shape of the prism was symmetric with respect to the mold surface, and the depth was constant in the plane. Next, prism shapes were molded from the mold onto the surface of the polycarbonate film using an ultraviolet curable resin. Furthermore, the surface of the polycarbonate film on which the prism was not formed was bonded to both surfaces of a transparent acrylic plate having a thickness of 2 mm to obtain a light control member (B-1) on which a convex prism was formed.

(2) In place of the transparent acrylic plate having a thickness of 2 mm, a thickness of 2 mm in which 0.15 parts by mass of light diffusing fine particles (trade name “Tospearl” 2000B, refractive index: 1.420) manufactured by GE Toshiba Silicone Co., Ltd.) is added. (Meth) acryl styrene copolymer resin plate (used resin: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “TX polymer” TX-800S, refractive index: 1.549) was prepared by extrusion molding, and the prism shape was made ultraviolet A polycarbonate film transferred with a curable resin was bonded together in the same manner to obtain a light control member (B-2) on which convex prisms were formed.

(3) Moreover, it replaced with the acrylic board of the said transparent thickness, and the thickness which added 1.0 mass part of light diffusible fine particles (GE Toshiba Silicone Co., Ltd. brand name "Tospearl" 2000B, refractive index: 1.420). A 2 mm (meth) acryl styrene copolymer resin plate (resin used: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “TX polymer” TX-800S, refractive index: 1.549) was prepared by extrusion molding, and the prism shape was The polycarbonate film transferred with the ultraviolet curable resin was bonded in the same manner to obtain a light control member (B-3) on which convex prisms were formed.

(Configuration of the backlight device used)
With the light control member obtained above facing the surface on which the convex prism is formed opposite to the linear light source side, the longitudinal direction of the cold cathode tube, which is a linear light source, and the convex prism ridge line substantially coincide with each other. As shown in FIG. 18, a light diffusion sheet F (trade name “Opal” BS-700, manufactured by Keiwa Co., Ltd.) was overlaid thereon. In addition, the linear light source C and the reflecting plate D used the backlight apparatus of the commercially available liquid crystal television set (The product name KDL-L32HVX by Sony Corporation).

(Evaluation of projection shadow and brightness measurement)
(A) About the shadow by a processus | protrusion, visual evaluation was performed and the result was shown in Table 1.
(B) About the brightness | luminance which shows the brightness of a backlight, it measured with the color luminance meter (BM-5A by Topcon Corporation), and the result was shown in Table 1.

Example 1
A horizontal section shown in FIG. 19 (a) using an acrylic resin (trade name “Paragrass” manufactured by Kuraray Co., Ltd., trade name: 6 mmt) instead of the protrusion attached to the backlight device (trade name KDL-L32HVX, manufactured by Sony Corporation). A circular protrusion having a diameter of 3 mm and a tip diameter of 1 mmφ was cut and produced using a lathe. The protrusions were attached and fixed to the backlight device using a double-sided tape. As shown in FIG. 1, the attachment position was an intermediate position of the linear light source.
When combined with the light control member (B-1), no shadow due to the protrusion was visible at the position where the protrusion and the light control member contacted. Further, as shown in Table 1, the measured luminance was a high value.

(Example 2)
The protrusions of Example 1 were used and evaluated in the same manner as Example 1 in combination with the light control member (B-2). The shadow caused by the protrusion at the position where the protrusion and the light control member contacted was not visible as in Example 1. Further, as shown in Table 1, the measured luminance was also a relatively high value.

(Comparative Example 1)
Evaluation was performed by combining the light control member (B-1) using the protrusions (white opaque: the shape is the same as in Example 1) attached to the backlight device used in Example 1. As a result, a shadow caused by the protrusion was clearly generated at a position where the protrusion and the light control member contact each other.

(Comparative Example 2)
The protrusion of Comparative Example 1 was used and combined with the light control member (B-3). Although the shadow caused by the protrusion was not visible at the position where the protrusion and the light control member were in contact, the measured luminance was a low value as shown in Table 1.

(Comparative Example 3)
Instead of the projections attached to the backlight device used in Example 1, acrylic resin (trade name “Paragrass” transparent plate 6 mmt manufactured by Kuraray Co., Ltd.) is used, and the shape of the horizontal cross section as shown in FIG. A circular projection having a tip diameter of 3 mmφ was cut by a lathe and produced. The protrusions were attached and fixed to the backlight device using a double-sided tape. As shown in FIG. 1, the attachment position was an intermediate position of the linear light source.
When combined with the light control member (B-1), a shadow caused by the protrusion was clearly confirmed at the position where the protrusion and the light control member contacted.

It is a cross-sectional schematic diagram of the backlight apparatus for liquid crystal display devices which is one embodiment of this invention. It is a cross-sectional partial enlarged view of the backlight apparatus for liquid crystal display devices which is one embodiment of this invention. It is the cross-sectional partial enlarged view of the backlight apparatus for liquid crystal display devices which is other one Embodiment of this invention. It is a model top view except the light control member of the backlight apparatus for liquid crystal display devices which is one embodiment of this invention. It is the elements on larger scale seen from diagonally upward of the backlight apparatus for liquid crystal display devices which is one embodiment of this invention. It is a schematic diagram explaining the advancing direction of the light beam just above the linear light source of a light control member. It is a schematic diagram explaining the advancing direction of the light ray in the linear light source part of a light control member. It is a figure which shows the angle which the ridgeline of an entrance plane prism makes. It is a schematic diagram explaining the advancing direction of the light ray when a protrusion is provided between the linear light source and the light control member. It is an incident energy distribution figure which illustrates typically the incident energy of the light ray which injects into the virtual surface provided on the some linear light source. FIG. 6 is a luminance distribution diagram schematically illustrating the luminance (incident energy) of a light beam incident on a light control member (virtual surface) directly above a linear light source. It is a luminance distribution figure explaining typically the luminosity (exit energy) of the light ray which injects into the light control member (virtual surface) between a plurality of linear light sources. It is a schematic block diagram explaining the incident angle of the light ray which injects into the light control member located between several linear light sources. It is a schematic block diagram explaining an example of the apparatus which measures the angle dependence of the total light transmittance of a light control member. It is a schematic block diagram explaining the advancing state of the light ray when light is incident on the light control member in an oblique direction. It is a schematic block diagram explaining the advancing state of the light ray when light is incident on the light control member in the vertical direction. It is a figure which shows the cross-sectional example of the unevenness | corrugation which can be formed in an output surface. It is a figure which shows the example of 1 structure of the illuminating device which concerns on an Example of this application. It is a figure which shows the shape of the protrusion concerning an Example and a comparative example.

Explanation of symbols

A Backlight module B Light control member C Linear light source (cold cathode tube)
D Reflector E Projection 2 Concave and convex shape 10 Concave and convex shape top 11 Concave and convex shape skirt 12 Incident light 13 Emitted light 14 Vertical incident light 15 Incident surface 16 Reflected light

Claims (6)

A plurality of linear light sources, a reflection plate that reflects light from the linear light source, a light control member that refracts and transmits light from the linear light source and the reflection plate, and holds the light control member In the illumination device including at least the protrusion, the reflector, the linear light source, and the light control member are arranged in this order from the light incident side to the light emitting side, the protrusion is made of a light-transmitting material, The horizontal cross section has a circular shape, and the diameter of the tip of the protrusion that contacts the light control member is 1 mm or less. The light control member has a light incident surface that mainly receives light and a light output surface that mainly emits light. The surface and / or the light exit surface has a concavo-convex shape, the distance between an arbitrary linear light source M and another linear light source N nearest to it is D, the linear light source M and the light control member If the distance to is H, any point on the entrance surface The total light transmittance of light incident at an angle of α = Tan ⁻¹ {(D / 2) / H} with respect to the normal direction of the incident surface is 50% or more, and the total light transmittance Is 1.05 times to 3 times the total light transmittance of light when light enters the point on the incident surface from the normal direction.   10 to 50% of light incident at an angle α with respect to the normal direction of the incident surface of the light control member is emitted in an angle range of −15 ° to + 15 ° with the normal direction of the output surface. The lighting device according to claim 1. The light control member has a flat incident surface, and has an uneven surface formed on the output surface. The light output portion has a cross section in at least one predetermined direction including the top of the uneven shape perpendicular to the output surface. When the refractive index of the light control member is n, the contour θ2 has an inclination θ2 of 0 ≦ | Sin ⁻¹ (n · sin (θ 2 −Sin ⁻¹ ((1 / n) · sin α) )) −θ2 | ≦ (π / 12) and the slope θ2 includes a region X that is less than Sin ⁻¹ (1 / n), the region X includes the top of the concavo-convex shape, The ratio between the length x of the direction component parallel to the exit surface and the length P of the direction component parallel to the exit surface of the entire contour line is 0.15 to 0.80. Lighting device described in   The light control member has an acute angle θ at which the contour line in the light emission part of the cross section at least in a predetermined direction including the top of the concavo-convex shape is perpendicular to the emission surface and the extension line intersects The illuminating device according to claim 1, further comprising: two substantially straight lines, and a convex curve connecting one ends of the two substantially straight lines.   A plurality of concavo-convex shapes are formed on the light exit surface of the light control member, and the cross section is perpendicular to the light exit surface and includes the top of the concavo-convex shape on the light exit surface in a direction parallel to the linear light source. The lighting device according to any one of claims 1 to 4, wherein a ridge line in the light emitting portion is a straight line extending in a direction parallel to the linear light source. A transmissive display element is provided on the illumination device according to claim 1.