JP4181792B2 - Light guide plate and flat illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent visible spectra (rainbow) by an optical element of the like and a dark streak pattern to obtain high-intensity output light. <P>SOLUTION: A light guide plate 2 has an incident part 7 guiding the light from a light source 3, a front surface part 8 causing the light to go out and a back surface part 9 located on a side opposite to the front surface part 8. Optical elements 20 having an inclined surface corresponding to the light flux from the light source 3 with continuity at a position corresponding to a luminance distribution or a light energy distribution of the light source 3 are laid on the front surface part 8 or/and the back surface part 9 with a density distribution functionally increasing in proportion to a distance from the light source 3. First optical deflection elements 30 in a concave or/and convex form finer than the optical element 20 are provided between continuous rows of the optical elements 20. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a light guide plate and a flat illumination device used for a liquid crystal display device or the like, and for any light source, a position corresponding to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceWith continuous or non-continuous installationIt has a density distribution that increases functionally in proportion to the distance from the light source, and it is bright even with a small light source such as a directional point light source, and even with a directional distribution light source that has a linear shape or the like. I get the light.
  Also continuous or discontinuousFirst optical deflecting element having a concave shape and / or a convex shape that is finer than the optical element between the rows of optical elementsAndA second light deflecting element that minutely refracts a part of the light emitted by the optical element is provided on the front surface or the back surface facing the optical element, and a plurality of rows with a white light source or the likeLight ofThe generation of the light spectrum that appears on the exit surface by the diffraction grating element or the Newton prism element by the optical element causes the first light deflection element to diffuse part of the light beam from the light source toward the optical element. Prevent occurrenceit can.
  furtherThe bright and dark stripes generated by a constant outgoing angle due to the interference of light beams, which are periodically totally reflected by the front and back portions, are finely disturbed by the second light deflecting element without reducing the outgoing luminance. Prevent the occurrence ofbe able to.
  Furthermore,The present invention relates to a light guide plate and a flat illumination device capable of preventing the second light deflection element and the convex first light deflection element provided on the front surface portion and the back surface portion from being in close contact with a nearby reflector or sheet. .
[0002]
[Prior art]
  Conventional light guide plates and flat illumination devices use a method that uses scattering on the back surface of the light guide plate. In this method, a dot or a rectangular shape is printed with an ink mixed with a white material such as titanium oxide as the distance from the light source increases, and scattered light is obtained as the distance from the light source increases. We are trying to obtain the uniformity of the emitted light. Further, an injection molding method is used, in which scattering is used for the front surface portion and the back surface portion of the light guide plate, and a minute uneven shape is randomly formed.
[0003]
  Similarly, as a light guide plate and a flat illumination device using an injection molding method, one using a method utilizing refraction or reflection on the front surface portion or the back surface portion of the light guide plate is known. In this method, the convex shape and the concave shape are simply formed so as to be distributed (gradation) more away from the light source, and the probability of refraction and reflection increases as the distance from the light source increases, and the light emitted from the light guide plate is made uniform. Yes.
[0004]
  Further, as a light guide plate and a flat illumination device using an injection molding method, one using a method using refraction or reflection on the front surface portion or the back surface portion of the light guide plate is also known. In this method, a prism shape is formed in parallel with the light source, and light rays from the light source are refracted or reflected by the sides of the prism to be deflected to the emission surface or emitted from the emission surface.
[0005]
  Similarly, a method is known in which a prism shape is provided in parallel with the light source on the front surface portion and the back surface portion of the light guide plate. In this method, the height or depth of the prism is set higher or deeper as the distance from the light source increases, the more light rays from the light source are received as the distance from the light source increases, and the reflected light or refractive light is used more. The emitted light is made uniform.
[0006]
  In particular, when the light source is mixed with a plurality of wavelengths such as a white light source, the light emitted from the emission surface is split into the visible spectrum and looks iridescent. For this reason, when a liquid crystal display device is mounted on these flat illumination devices, a problem as a color liquid crystal screen occurs when the dispersed light corresponds to RGB (red, green, blue) of the liquid crystal.
[0007]
  Furthermore, a bright and dark stripe pattern is generated on the exit surface due to regular brightness of the emitted light. For this reason, when a liquid crystal display device is mounted on these flat illumination devices, the brightness on the screen appears, making it difficult to see.
[0008]
[Problems to be solved by the invention]
  Conventional light guide plates and flat illumination devices use a method of utilizing scattering on the back surface of the light guide plate, and the more the circular or rectangular shape is separated from the light source by using ink mixed with a white material such as titanium oxide. Many dots were printed, and scattered light was obtained as the distance from the light source was increased to obtain uniformity of light emitted from the light guide plate. However, the light was absorbed by the white material or ink, and the light was scattered. As a result, the light beam does not reach only the exit surface, and there is a problem in luminance because the absolute amount of emitted light is low.
[0009]
  In addition, there is no loss due to light absorption in the method in which fine irregularities are randomly formed on the front and back surfaces of the light guide plate by injection molding, and the light from the light source is scattered. Are scattered, the light beam does not reach only the exit surface, the brightness of the exit light is low, and the uneven distribution is random, causing problems with brightness spots and the like.
[0010]
  Similarly, when the distribution of the convex shape or concave shape increases as the distance from the light source is increased (gradation), it is improved compared to printing of ink or the like, or random shaping of fine uneven shapes, but it is merely away from the light source. The probability of refraction and reflection is only increased, and it does not correspond to the directivity (luminance distribution) of the light beam or the shape of the light source. There are no challenges.
[0011]
  Furthermore, a method of forming a prism shape in parallel with the light source on the front surface portion and the back surface portion of the light guide plate, refracting or reflecting light rays from the light source on the sides of the prism and deflecting to the output surface, or emitting from the output surface, This is true if all of the prism ridge lengths have the same condition (in the case of a simple ideal state), but in reality, the light source directivity (luminance distribution) and the shape of the light source are not supported. There is a problem that the amount of light, directivity, and energy are not fully utilized.
[0012]
  Similarly, a prism shape is provided on the front and back surfaces of the light guide plate in parallel with the light source, and the height and depth of the prism are set higher or deeper as the distance from the light source increases, and more light from the light source is received as the distance from the light source increases. Thus, a method that uses a lot of reflected light and refracted light to make the emitted light uniform regardless of the distance from the light source is good as a method away from the light source, but the prism itself is actually pointing the light source. However, there is a problem that the light amount, directivity, and energy of the light source are not sufficiently used because they are not compatible with the characteristics (luminance distribution) and the shape of the light source.
[0013]
  In any case, these conventional methods do not correspond to the directivity of the light amount of the light source, the energy distribution, the shape of the light source, and the like, and these conventional methods are limited.
[0014]
  In particular, when a light source is mixed with a plurality of wavelengths such as a white light source, the light emitted from the emission surface is split into a visible spectrum and looks like a rainbow color. For this reason, when a liquid crystal display device is mounted on these flat illumination devices, a problem as a color liquid crystal screen occurs when the dispersed light corresponds to RGB (red, green, blue) of the liquid crystal. In order to eliminate this problem, a scattering sheet or the like is placed for the purpose of scattering the dispersed light above the light guide plate, but the emitted light with directivity is scattered, or by absorption of light by the scattering sheet, etc. There is a problem in lowering luminance.
[0015]
  In addition, the regular brightness of the emitted light causes a light and dark stripe pattern on the exit surface, and when a liquid crystal display device is placed on these flat illumination devices, the intensity of brightness on the screen appears. It will be awkward. In order to solve this problem, a method of placing a diffusion sheet or the like above the light guide plate to make it difficult to see the bright and dark stripe pattern is used, but there is a problem that causes a decrease in luminance as a whole. In addition, with the increase in the number of members such as the scattering sheet and the diffusion sheet, there are problems in assembly man-hours and member costs.
[0016]
  Furthermore, a minute concave shape is randomly formed on the front and back surfaces of the light guide plate by injection molding and a light guide plate that performs dot printing using ink mixed with a white material such as titanium oxide on the back surface. In the case of a light guide plate, the light guide plate is in close contact with a diffusion sheet or the like provided at the upper portion of the front surface portion, a reflector or a reflective case at the lower portion of the back surface portion, and the like. For this reason, the position where the air layer is refracted shifts, and there is a problem that the effect of the diffusion sheet and the like is reduced by half. Moreover, in order to return the light leaked from the light guide plate to the reflector or the reflection case again, the reflector or the reflection case is made white, but it is in close contact with the light guide plate. There is a problem that the surface of the light can be seen through the (white) light guide plate.
[0017]
  The present invention has been made to solve the above-described problems. Compared to the conventional technique, the present invention always corresponds to the light flux from the light source at a position corresponding to the directivity of the light amount from the light source and the energy distribution.LeaningAn optical element with a slopeNon-continuous or continuousBy providing it, a position where the brightness and energy from the light source are always equalLightEquivalent brightness and energy can be emitted to the exit surface side by total reflection and refraction by the inclined surface of the optical element..
  Also,The optical element density distribution is increased in proportion to the distance from the light source as the luminance and energy from the light source are attenuated, so that the product of the amount of emitted light and the emission angle can be emitted equally at any position of the light guide plate..
  further,A first light deflecting element having a concave shape and / or a convex shape that is finer than the optical element is provided between the optical element rows, and a plurality of rows with a highly directional white light source or the likeLight ofA rainbow-like visible spectrum is generated by light splitting on the light exit surface by a diffraction grating element or a Newton prism spectroscopic element by a scientific element, and a part of a light beam traveling from a light source to an optical element is generated by a first light deflecting element. It can diffuse and prevent the generation of spectroscopy (rainbow).
[0018]
  In addition, the light incident on the light guide plate from the end portions of the front surface and back surface connected to the incident portion of the light guide plate is repeatedly totally reflected on the front surface and back surface.AccompanyingA second light deflecting element that minutely refracts a part of light emitted from bright and dark lights having different brightness due to interference is provided, and a part of the light beam reaching the exit surface has a diameter larger than the height (so-called radius of curvature). (A part of a large arc) of the second light deflecting element that reaches the second light deflecting element and emits the light from the second light deflecting element to the outside at a different exit angle that is smaller than the flat surface portion, Generation of periodic brightness of emitted light can be prevented.
[0019]
  Further, the first light deflecting element and the second light deflecting element having a convex shape provided on the front surface portion and the back surface portion of the light guide plate, a diffuser sheet provided on the upper surface portion, and a reflector on the lower portion of the back surface portion. The light guide plate and the flat surface can prevent the adhesion between the light guide plate and the reflection case, and draw out the effect of the diffusion sheet, etc., or can not directly see the reflector or the surface of the reflection case through the (white) light guide plate The object is to provide a lighting device.
[0020]
[Means for Solving the Problems]
  The light guide plate according to claim 1 of the present invention has a front surface portion and / or a back surface portion corresponding to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceInstall continuously and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightA first light deflecting element having a concave shape and / or a convex shape that is finer than the optical element is provided between the optical element rows.
[0021]
  The light guide plate according to claim 1 is a position in which the front surface portion and / or the back surface portion corresponds to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceInstall continuously and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightSince the first light deflection element having a concave shape and / or convex shape that is finer than the optical element is provided between the rows of the optical elements, the luminance and energy from the light source are always equal.LightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. Moreover, the product of the amount of light emitted at every position of the light guide plate and the solid angle is equally emitted so that the optical element density distribution increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. can do. In addition, a highly directional white light source and multiple rowsLight ofThe first light deflecting element diffuses a part of the light beam from the light source to the optical element by generating the light spectrum (rainbow) appearing on the exit surface by the diffraction grating element or the Newton prism spectroscopic element. Can do.
[0022]
  Furthermore, with a convex first light deflecting element provided on the front surface portion or the back surface portion of the light guide plate, a diffusion sheet or the like provided near the front surface portion or the back surface portion, a reflector or case below the back surface portion, etc. Adhesion with the light guide plate can be prevented.
[0023]
  The light guide plate according to claim 2 is a position corresponding to the luminance distribution or light energy distribution of the light source on the front surface part and / or the back surface part.LightAn optical element having an inclined surface corresponding to the light flux from the sourceDiscontinuous installation and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightA first light deflecting element having a concave shape and / or a convex shape that is finer than the optical element is provided between the optical element rows.
[0024]
  In the light guide plate according to claim 2, the front surface part and / or the back surface part corresponds to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceDiscontinuous installation and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightSince the first light deflection element having a concave shape and / or convex shape that is finer than the optical element is provided between the rows of the optical elements, the luminance and energy from the light source are always equal.LightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. Moreover, the product of the amount of light emitted at every position of the light guide plate and the solid angle is equally emitted so that the optical element density distribution increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. can do. in addition,DiscontinuousHowever, by controlling the length of the optical element and the distance between adjacent optical elements, the product of the amount of light emitted from the optical element is equal to the solid angle, but there is no optical Light energy lower than that of the element can be obtained. In addition, a multi-row with a highly directional white light source, etc.Light ofThe first light deflecting element diffuses a part of the light beam from the light source to the optical element by generating the light spectrum (rainbow) appearing on the exit surface by the diffraction grating element or the Newton prism spectroscopic element. Can do.
[0025]
  Furthermore, with a convex first light deflecting element provided on the front surface portion or the back surface portion of the light guide plate, a diffusion sheet or the like provided near the front surface portion or the back surface portion, a reflector or case below the back surface portion, etc. Adhesion with the light guide plate can be prevented.
[0026]
  Furthermore, the light guide plate according to claim 3 is provided with a larger number of first light deflecting elements on the front surface portion and / or back surface portion as it is closer to the random or incident portion, and the height is in the range of 1 μm to 4 μm and the maximum width is 4 μm. A polygonal pyramid shape in a range of ˜16 μm or an arc shape or a cone shape in a range of 4 μm to 16 μm.
[0027]
  The light guide plate according to claim 3 is provided with more first light deflecting elements on the front surface portion and / or back surface portion as random or closer to the incident portion, and has a height in the range of 1 μm to 4 μm and a maximum width of 4 μm to 16 μm. Since the shape is a polygonal pyramid shape in the range or a circular arc shape or a conical shape in the range of 4 μm to 16 μm, it is finer than the optical element, so that the first light deflecting element does not greatly affect the emitted light. The light emitted from the optical element can be controlled by the deflected light beam from the first light deflecting element. Moreover, multiple rows for white light source with strong directivity or high brightnessLight ofSince the generation of a visible spectrum due to light spectroscopy appears particularly on the exit surface near the incident part due to the diffraction grating element by the optical element, the first light deflecting element is increased as it is closer to the incident part on the front surface part and / or the back surface part. It is possible to diffuse a part of the light beam from the light source toward the optical element, or to emit a light beam having a different emission angle on the emission surface.
[0028]
  In addition, when the white light source has a weak directivity, the light incident on the light guide plate from the end of the front and back surfaces connected to the incident portion of the light guide plate is repeatedly totally reflected on the front and back surfaces.AccompanyingA part of light emitted from bright and dark lights having different luminance due to interference is diffused in a minute amount by partially providing the first light deflection element on the front surface part and / or the back surface part. Can do.
[0029]
  In the light guide plate according to claim 4, the front surface portion and / or the back surface portion corresponds to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceInstall continuously and optical elementsSurface or back surface facing the optical element with a density distribution that increases functionally in proportion to the distance from the light sourceLightA second light deflecting element is provided that minutely refracts part of the light emitted from the optical element.
[0030]
  The light guide plate according to claim 4 is a position corresponding to the luminance distribution or light energy distribution of the light source on the front surface part and / or the back surface part.LightAn optical element having an inclined surface corresponding to the light flux from the sourceInstall continuously and optical elementsSurface or back surface facing the optical element with a density distribution that increases functionally in proportion to the distance from the light sourceLightSince the second light deflecting element that minutely refracts part of the light emitted from the optical element is provided, the brightness and energy from the light source are always equal.LightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. Moreover, the product of the amount of light emitted at every position of the light guide plate and the solid angle is equally emitted so that the optical element density distribution increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. can do. In addition, the light incident on the light guide plate from the end of the front and back surfaces connected to the incident portion of the light guide plate is repeatedly totally reflected on the front and back surfaces.AccompanyingA part of bright and dark light beams having periodicity with different brightness and the like that reach the exit surface due to interference is a second light deflection element having a large diameter with respect to the height (so-called part of an arc having a large curvature radius). When the light beam reaches and exits from the second light deflecting element, the light beam is emitted at a different emission angle that is slightly smaller than the flat surface portion. Can be broken.
[0031]
  In addition, the second light deflection element provided on the front surface portion or the back surface portion of the light guide plate can prevent the light guide plate from being in close contact with the diffusion sheet or the like provided near the front surface portion or the back surface portion.
[0032]
  Furthermore, in the light guide plate according to claim 5, the front surface part and / or the back surface part is a position corresponding to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceDiscontinuous installation and optical elementsSurface or back surface facing the optical element with a density distribution that increases functionally in proportion to the distance from the light sourceLightA second light deflecting element is provided that minutely refracts part of the light emitted from the optical element.
[0033]
  In the light guide plate according to claim 5, the front surface portion and / or the back surface portion corresponds to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceDiscontinuous installation and optical elementsSurface or back surface facing the optical element with a density distribution that increases functionally in proportion to the distance from the light sourceLightSince the second light deflecting element that minutely refracts part of the light emitted from the optical element is provided, the brightness and energy from the light source are always equal.LightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. Moreover, the product of the amount of light emitted at every position of the light guide plate and the solid angle is equally emitted so that the optical element density distribution increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. can do. In addition, although it is continuous, the product of the amount of light emitted from the optical element and the solid angle can be emitted equally by controlling the length of the optical element and the interval between adjacent optical elements. Furthermore, the light rays that have entered the light guide plate from the end portions of the front surface portion and the back surface portion connected to the incident portion of the light guide plate are repeatedly totally reflected on the front surface portion and the back surface portion.AccompanyingA part of bright and dark light beams having periodicity with different brightness reaching the exit surface due to interference reaches the second light deflection element having a large diameter with respect to the height (so-called part of an arc having a large curvature radius). However, when the light is emitted from the second light deflecting element to the outside, the light is emitted at a different emission angle that is slightly smaller than the flat surface portion. Can be broken.
[0034]
  In addition, the second light deflection element provided on the front surface portion or the back surface portion of the light guide plate can prevent the light guide plate from being in close contact with the diffusion sheet or the like provided near the front surface portion or the back surface portion.
[0035]
  The light guide plate according to claim 6 is an arc shape in which the diameter of the second light deflection element is in the range of 5 μm to 100 μm and the height is in the range of 1/20 to 1/80 of the diameter, and the front surface portion or the back surface. It is characterized in that a larger number is provided closer to the part or closer to the incident part.
[0036]
  In the light guide plate according to claim 6, since the diameter of the second light deflection element is an arc shape in the range of 5 μm to 100 μm and the height is in the range of 1/20 to 1/80 of the diameter, Since the diameter is large (a part of a so-called arc having a large curvature radius), the normal line of the second light deflecting element is only slightly different from the normal line of the light guide plate.
[0037]
  In addition, since the second light deflecting element is provided on the front surface portion or the back surface portion so as to be random or closer to the incident portion, the light beam incident on the light guide plate from the end portions of the front surface portion and the back surface portion connected to the incident portion of the light guide plate Repeats total reflection on the front and backAccompanyingGeneration of bright and dark light with different luminance due to interference can be prevented by providing the second light deflecting element randomly on the front surface or the back surface. Since the bright and dark stripe pattern is more conspicuous in the vicinity of the portion than in other places, the more light and dark stripe patterns can be prevented by providing more second light deflecting elements closer to the incident portion on the front surface portion or the rear surface portion.
[0038]
  Furthermore, the light guide plate according to claim 7 is characterized in that the cross section of the optical element has a triangular shape, a trapezoidal shape, or an arc shape, and is continuous or discontinuous.
[0039]
  In the light guide plate according to claim 7, since the cross section of the optical element has a triangular shape, a trapezoidal shape, and an arc shape and is continuous or discontinuous, the light rays that have entered the light guide plate from the incident portion of the light guide plate are triangular, The trapezoidal and arc-shaped inclined surfaces can exist at positions corresponding to the light flux from the light source, and when these are continuous, the same brightness and energy can be emitted at any position, Even if it exists, the same brightness | luminance and energy can be radiate | emitted continuously in any position.
[0040]
  The light guide plate according to claim 8 is characterized in that the height of the optical element is increased or / and partially raised or lowered as the optical element is moved away from the light source.
[0041]
  In the light guide plate according to the eighth aspect, the height of the optical element is increased or / and partially raised or lowered as the optical element is moved away from the light source, so that even the optical element far from the light source receives light rays from the light source and performs total reflection. The amount of light emitted from the light guide plate and the angle of light emission can be changed by partially raising or lowering the height.
[0042]
  Furthermore, the light guide plate according to claim 9 is characterized in that an angle between the inclined surface and the front surface portion and the back surface portion is in a range from π / 2-2 · critical angle to critical angle.
[0043]
  In the light guide plate according to claim 9, since the angle between the inclined surface and the front surface portion and the back surface portion is in the range of π / 2-2 · critical angle to critical angle, from the maximum incident angle of the light beam guided into the light guide plate By using the range up to the minimum angle that breaks the critical angle, all the reflected light can break the critical angle.
[0044]
  The light guide plate according to claim 10 is characterized in that the angle formed between the front surface portion and the back surface portion of the inclined surface in proportion to the distance from the light source approaches the critical angle.
[0045]
  In the light guide plate according to the tenth aspect, the angle formed between the front surface portion and the back surface portion in proportion to the distance from the light source approaches the critical angle. The reflected light that is totally reflected in proportion to the distance is emitted at a small emission angle. For this reason, the product of the light quantity emitted and the solid angle can be emitted equally at any position on the emission surface of the light guide plate.
[0046]
  Furthermore, the light guide plate according to claim 11 is configured such that the inclined surface has an arc on the inside or the outside centered on the center portion of the inclined surface, or an arc is formed on the inside and outside of the inclined surface partially. Features.
[0047]
  In the light guide plate according to the eleventh aspect, since the inclined surface has an arc on the inside or outside with the central portion of the inclined surface as the center, or partially on the inside and outside of the inclined surface, the same size is obtained. In the case where the emission position in the light guide plate is an arc on the inside of the inclined surface, it can be brought closer to the light source side. Further, when the light source is near, the totally reflected light becomes parallel light, and when the light source is far, the totally reflected light can be collected.
[0048]
  Further, when the emission position in the light guide plate having the same size is formed as an arc on the outer side of the inclined surface, it can be moved away from the light source side. Further, when the light source is near, the totally reflected light becomes parallel light, and when the light source is far, the totally reflected light can be diffused.
  Further, different actions such as condensing and diffusing can be obtained on one inclined surface by forming a circular arc partially inside and outside on one inclined surface.
[0049]
  The planar illumination device according to claim 12 is a light source, an incident portion that guides light from the light source, and a position corresponding to the luminance distribution or light energy distribution of the light source.LightIt has an inclined surface corresponding to the light flux from the source.The optical elements to be installed continuously and the optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightLight emitted from the optical element to the front surface portion or the back surface portion facing the first optical deflection element or / and the optical element that is finer than the optical element between the rows of the optical elements and finer than the optical element A light guide plate provided with a second light deflection element that slightly refracts a part of the light guide plate, and a reflector that covers the light guide plate other than the incident portion and the exit surface and reflects the leaked light from the light guide plate again into the light guide plate It is characterized by comprising.
[0050]
  The planar illumination device according to claim 12 is a light source, an incident portion that guides light from the light source, and a position corresponding to the luminance distribution or light energy distribution of the light source.LightIt has an inclined surface corresponding to the light flux from the source.The optical elements to be installed continuously and the optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightLight emitted from the optical element to the front surface portion or the back surface portion facing the first optical deflection element or / and the optical element that is finer than the optical element between the rows of the optical elements and finer than the optical element A light guide plate provided with a second light deflection element that slightly refracts a part of the light guide plate, and a reflector that covers the light guide plate other than the incident portion and the exit surface and reflects the leaked light from the light guide plate again into the light guide plate Because it has, the position where the brightness and energy from the light source are always equalLightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. In addition, the density distribution of the optical element increases functionally in proportion to the distance from the light source as the brightness and energy from the light source decay, and the amount of light emitted from any position of the light guide plate and its solid angle It is possible to emit the same product or to freely control the exit angle from the exit surface by setting the angle of the inclined surface.
[0051]
  In addition, a multi-row with a highly directional white light source, etc.Light ofThe first light deflecting element diffuses a part of the light beam from the light source to the optical element by generating the light spectrum (rainbow) appearing on the exit surface by the diffraction grating element or the Newton prism spectroscopic element. The light beam that has entered the light guide plate from the end of the front and back surfaces connected to the incident portion of the light guide plate is repeatedly totally reflected on the front and back surfaces.AccompanyingA part of bright and dark light beams having periodicity with different brightness and the like that reach the exit surface due to interference is a second light deflection element having a large diameter with respect to the height (so-called part of an arc having a large curvature radius). When the light beam reaches and exits from the second light deflecting element, the light beam is emitted at a different emission angle that is slightly smaller than the flat surface portion. Can be broken.
[0052]
  In addition, the convex first light deflecting element and the second light deflecting element provided on the front surface portion and the back surface portion of the light guide plate, and the diffusion sheet provided in the vicinity of the front surface portion and the back surface portion and the lower portion of the back surface portion. It is possible to emit light while preventing adhesion between a light reflector and a certain reflector or reflection case.
[0053]
  Furthermore, the planar illumination device according to claim 13 is a light source, an incident portion that guides light from the light source, and a position corresponding to the luminance distribution or light energy distribution of the light source.LightIt has an inclined surface corresponding to the light flux from the source.Discontinuous optical elements and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightLight emitted from the optical element to the front surface portion or the back surface portion facing the first optical deflection element or / and the optical element that is finer than the optical element between the rows of the optical elements and finer than the optical element A light guide plate provided with a second light deflection element that slightly refracts a part of the light guide plate, and a reflector that covers the light guide plate other than the incident portion and the exit surface and reflects the leaked light from the light guide plate again into the light guide plate It is characterized by comprising.
[0054]
  The flat illumination device according to claim 13 includes a light source, an incident portion that guides light from the light source, and a position corresponding to the luminance distribution or light energy distribution of the light source.LightIt has an inclined surface corresponding to the light flux from the source.Discontinuous optical elements and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightLight emitted from the optical element to the front surface portion or the back surface portion facing the first optical deflection element or / and the optical element that is finer than the optical element between the rows of the optical elements and finer than the optical element A light guide plate provided with a second light deflection element that slightly refracts a part of the light guide plate, and a reflector that covers the light guide plate other than the incident portion and the exit surface and reflects the leaked light from the light guide plate again into the light guide plate Because it has, the position where the brightness and energy from the light source are always equalLightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. Moreover, the product of the amount of light emitted at every position of the light guide plate and its solid angle is equal so that the density distribution of the optical element increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. The emission angle from the exit surface and the optical element itself by exiting or setting the angle of the inclined surfaceChangeCan be
[0055]
  In addition, a multi-row with a highly directional white light source, etc.Light ofThe first light deflecting element diffuses a part of the light beam from the light source to the optical element by generating the light spectrum (rainbow) appearing on the exit surface by the diffraction grating element or the Newton prism spectroscopic element. The light beam that has entered the light guide plate from the end of the front and back surfaces connected to the incident portion of the light guide plate is repeatedly totally reflected on the front and back surfaces.AccompanyingA part of bright and dark light beams having periodicity with different brightness and the like that reach the exit surface due to interference is a second light deflection element having a large diameter with respect to the height (so-called part of an arc having a large curvature radius). When the light beam reaches and exits from the second light deflecting element, the light beam is emitted at a different emission angle that is slightly smaller than the flat surface portion. Can be broken.
[0056]
  In addition, the convex first light deflecting element and the second light deflecting element provided on the front surface portion and the back surface portion of the light guide plate, and the diffusion sheet provided in the vicinity of the front surface portion and the back surface portion and the lower portion of the back surface portion. It is possible to emit light while preventing adhesion between a light reflector and a certain reflector or reflection case.
[0057]
  Furthermore, the planar illumination device according to claim 14 is characterized in that the light source is a white light source having directivity or / and directivity distribution.
[0058]
  In the flat illumination device according to the fourteenth aspect, since the light source is a white light source having directivity or / and directivity distribution, when the distance from the incident portion of the light guide plate is not equal, directivity is increased in a direction far from the incident portion. Can be matched.
[0059]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
  Note that the present invention provides a position corresponding to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceProvide continuous or discontinuous optical elementsDensity distribution that increases functionally in proportion to the distance from the light sourceApplied continuouslyandDiscontinuousThe first light deflection element having a finer concave shape or convex shape than the optical element is provided between the rows of the optical elements, or from the end portions of the front surface portion and the back surface portion connected to the incident portion of the light guide plate The light incident on the light guide plate repeats total reflection on the front and back surfaces.AccompanyingA second light deflection element that minutely refracts a part of bright and dark light beams having different periodicities and the like that reach the emission surface due to interference is provided, and a visible spectrum (rainbow) or bright and dark light fringes by an optical element or the like is provided. It is an object of the present invention to provide a light guide plate and a flat illumination device capable of preventing generation of a pattern and obtaining high-luminance outgoing light.
[0060]
  1 is a schematic exploded view of a flat illumination device according to the present invention, FIGS. 2 to 13 are schematic views of a light guide plate according to the present invention, FIG. 14 is a partially enlarged view of the light guide plate of FIG. 10, and FIGS. FIG. 18 to FIG. 20 are schematic locus diagrams of light beams of a light guide plate according to the present invention, and FIG. 21 is a schematic diagram of a light guide plate according to the present invention. In FIG. 1 to FIG. 14, the extremely small first light deflection element 30 and second light deflection element 40 are exaggerated on a part of the light guide plate 2.
[0061]
  As shown in FIG. 1, the flat illumination device 1 is generally composed of a light guide plate 2, a light source 3, a reflector 14, and a reflection case 15.
[0062]
  The light guide plate 2 is formed of a transparent acrylic resin (PMMA) or polycarbonate (PC) having a refractive index of about 1.4 to 1.7. The light guide plate 2 includes a side surface portion 11, a front surface portion 8 for light emission, and a back surface portion 9 located on the opposite side and an incident portion 7 that guides light from the light source 3.
[0063]
  As shown in FIGS. 2 to 9, the light guide plate 2 is connected to the position corresponding to the luminance distribution or light energy distribution of the light source 3 without interruption.ContinuedFurther, the optical element 20 can be applied to the front surface portion 8 and / or the back surface portion 9.
[0064]
  Further, as shown in FIGS. 10 to 13, the light guide plate 2 is spaced at a predetermined interval with respect to the position corresponding to the luminance distribution or light energy distribution of the light source 3.DiscontinuousThe optical element 20 ′ may be provided on the front surface portion 8 and / or the back surface portion 9.
[0065]
  Further, the light guide plate 2 is attached to the front surface 8 or / and the back surface 9.Continuous optical element 20 or discontinuous optical element 20 'Optical element 20 between the rows ofAnd optical element 20 'The first light deflecting element 30 having a finer concave shape and / or convex shape can be provided. In the example of FIG.ContinuedThe first light deflection element 30 having a concave shape and / or a convex shape that is finer than the optical element 20 is provided between the rows of the optical elements 20.
[0066]
  In the light guide plate 2, light incident on the front surface portion 8 or the rear surface portion 9 from the front surface portion 8 connected to the incident portion 7 of the light guide plate 2 and the end portion 7 ′ of the rear surface portion 9 into the light guide plate 2. And repeated total reflection at the back 9AccompanyingThe second light deflection element 40 that minutely refracts a part of bright and dark light beams having different periodicities with different brightness reaching the exit surface by interference can be provided. In the example of FIG. 1, the second light deflection element 40 is provided on the surface portion 8.
[0067]
  Here, FIG. 14 is a predetermined interval shown in FIG.Led byProvided on the front surface 8 and back surface 9 of the optical plate 2DiscontinuousIt is the elements on larger scale of optical element 20 '.
[0068]
  As shown in FIG. 14, the length of the optical element 20 ′ is shortened, for example, 20′a to reduce the total reflection amount on the inclined surface, or the length of the optical element 20 ′ is increased on the inclined surface, such as 20′b. Increase the amount of total reflection. Thereby, the total reflection amount from the optical element 20 'can be controlled.
[0069]
  Further, the interval between adjacent optical elements 20 'is controlled. For example, the interval is lengthened as 21a or the interval is shortened as 21b. As a result, the product of the amount of light emitted from the optical element 20 ′ and the solid angle thereof are equal, but the place where the optical element 20 ′ is missing (distance 21a and 20b) is where the optical element 20 ′ is present. Get low light energy. Thereby, a desired luminance distribution can be expressed in the light guide plate 2.
[0070]
  Furthermore, as the light guide plate 2 moves away from the light source 3, the luminance and energy from the light source 3 are attenuated. For this reason, the optical element 20 is increased as the distance from the incident portion 7 increases. The optical element 20 applied to the front surface portion 8 and / or the back surface portion 9 has a density distribution that increases exponentially in proportion to the distance from the light source 3. Thereby, the product of the unit area of the optical element 20 in the vicinity of the incident part 7 and the strong light intensity, and the product of the unit area of the optical element 20 in the vicinity of the reflection end face part 10 away from the incident part 7 and the weak light intensity. Are equal.
[0071]
  The light guide plate 2 has a cross section of a triangular shape, a trapezoidal shape, and an arc shape so that the optical element 20 has an inclined surface corresponding to the light flux from the light source 3. Thereby, the light beam from the light source 3 is efficiently totally reflected on the inclined surface without loss.
[0072]
  Further, although not shown, the light guide plate 2 increases the height of the optical element 20 as the optical element 20 is moved away from the light source 3. Thereby, the height of an inclined surface part can be made high, and the area of an inclined surface part can be enlarged. As a result, the optical element 20 far from the light source 3 can receive a large amount of light from the light source 3. The received light is totally reflected on the inclined surface and deflected in the direction of the exit surface, so that a large amount of the exit light can be emitted even at a position far from the light source 3, and the light can be uniformly guided regardless of the distance of the light source 3. The emission brightness from the optical plate 2 can be obtained.
[0073]
  Although not shown, the light guide plate 2 can raise or lower the height of the inclined surface portion by partially raising or lowering the optical element 20. Thereby, the area of an inclined surface part can be enlarged or reduced. As a result, the amount of light emitted from an arbitrary position of the light guide plate 2 can be increased or decreased, and the angle of emission from an arbitrary position of the light guide plate can be changed. As a result, it is possible to control the luminance at a desired position of the light guide plate 2 and the viewing angle.
[0074]
  It should be noted that by partially changing the height of the optical element 20, for example, when the cross-sectional area is a triangular optical element 20, the height of one continuous triangular ridge can be continuously changed. The change of the emitted light can be made continuous.
[0075]
  In addition, the angle between the inclined surface of the optical element 20 and the front surface portion 8 and the back surface portion 9 is in the range of π / 2-2 · critical angle γ to critical angle γ. That is, the angle formed between the front surface portion 8 and the back surface portion 9 is made closer to the critical angle γ as the inclined surface is separated from the light source 3 in proportion to the distance from the light source 3.
[0076]
  Here, when the light from the light source 3 is guided from the incident part 7 to the inside of the light guide plate 2, for example, when the material of the light guide plate 2 is polycarbonate (PC) resin, the refractive index n of the polycarbonate resin is 1.59. Therefore, the light ray L0 that enters the light guide plate 2 from the air layer and exists in the light guide plate 2 is 0 ≦ | α | ≦ sin.^-1According to the equation (1 / n) (where n is an air layer and refractive index n = 1), the angle of refraction α is approximately within a range of ± 38.9713 °.
[0077]
  Further, the light incident on the light guide plate 2 within the range of the refraction angle α = ± 38.997 ° is sin γ = (1 / n at the boundary surface between the light guide plate 2 and the air layer (refractive index n = 1). ) Can be used to express the critical angle. For example, since the refractive index of polycarbonate resin which is a resin material used for the general light guide plate 2 is about n = 1.59, the critical angle γ is about γ = 38.97 °. In the case of a light guide plate using an acrylic resin (PMMA) material, the refractive index n of the acrylic resin is about n = 1.49, and the refraction angle α is about α = ± 42.38 °. The critical angle γ is also about γ = 42.38 °.
[0078]
  For example, the refractive index n of the light guide plate 2 made of acrylic resin is about n = 1.49, and in the example of FIG. 20, the refraction angle α of the light beam entering the light guide plate 2 is about α = 42.38 °. Accordingly, the optical element 20 provided on the back surface portion 9 of the light guide plate 2 has an angle θ formed with the back surface portion 9 (from π / 2-2 · 42.38 °) in the range of 5.24 ° to 42.38 °. Among them, an inclined surface 21 having an angle θ1 = 5.24 ° which is a minimum value is provided in the vicinity of the incident portion 7, and an inclined surface 22 having an angle θ2 = 42.38 ° which is a maximum value is provided at a position away from the incident portion 7. Is provided.
[0079]
  Among the light beams guided into the light guide plate 2 having the above-described configuration, a light beam L1 having an incident angle β of approximately 42 ° that is close to the incident portion 7 is on the inclined surface 21 of the optical element 20 (inclination θ1 = 5.24 °). Total reflection. The totally reflected light beam L11 travels in the direction of the surface portion 8 of the light guide plate 2. Here, the light beam L11 breaks the critical angle γ (outgoing angle of about 61 °) and exits from the surface portion 8 (outgoing angle of about 61 °). The light is emitted as L12.
[0080]
  In this way, light rays having a small refraction angle among the light rays that have entered the light guide plate 2 are incident angles other than the light rays that have traveled in the extending direction of the light guide plate 2 (the reflection end face portion 10 opposite to the incident portion 7). There are many light rays having a large diameter near the incident portion. Therefore, the inclined surface 21 of the optical element 20 provided in the vicinity of the incident portion is inclined even by a light beam having a large incident angle so that the angle formed with the rear surface portion 9 is reduced by 90.degree. The light is totally reflected at the surface 21, proceeds in the direction of the surface portion 8, breaks the critical angle γ of the light guide plate 2, and can be emitted from the surface portion 8.
[0081]
  In addition, among the light beams guided into the light guide plate 2, the light beam L2 having a light incident angle β = 2 ° that travels in a direction away from the incident portion 7 is the inclined surface 22 of the optical element 20 (inclination θ1 = 42.38). Total reflection at °). The totally reflected light beam L21 travels in the direction of the surface portion 8 of the light guide plate 2, where the light beam L21 breaks the critical angle γ (outgoing angle 2.24 °) outside the surface portion 8 (about 1.5 °). About) The light is emitted as outgoing light L22.
[0082]
  In this way, light rays having a small refraction angle among the light rays that have entered the light guide plate 2 travel in the extending direction of the light guide plate 2 (opposite direction of the incident portion 7), and enter the optical element 20 provided near the incident portion 7. There is little probability of collision. For this reason, the inclined surface 22 of the optical element 20 provided at a position away from the incident portion 7 is set so that the angle formed with the rear surface portion 9 is equal to the critical angle γ, and even the light having a small incident angle is totally reflected by the inclined surface 22. Then, it can proceed in the direction of the surface portion 8, break the critical angle γ of the light guide plate 2, and emit from the surface portion 8.
[0083]
  Therefore, as can be seen from the explanation of the two extreme cases as described above, in the light guide plate of this example, the inclination angle of the inclined surface of the optical element 20 increases with increasing distance from the incident portion 7 with respect to the light beam from the incident portion 7. The angle formed with the back surface portion 9 is made closer to the critical angle γ in proportion to the distance from the light source 3 so that the inclined surface 21 gradually becomes the inclined surface 22. As a result, the product of the amount of light emitted from any position on the exit surface of the light guide plate 2 by the optical element 20 corresponding to the distance from the light source 3 and the solid angle thereof is equal even with the attenuation of luminance and energy from the light source 3. Can be emitted.
[0084]
  Here, the optical element 20 provided with the inclined surface on the back surface portion 9 has been described. However, as described above, the light incident from the incident portion 7 is, for example, acrylic resin, the refraction angle α is α = ±. In the case of 42.38 °, polycarbonate resin, the refraction angle α is α = ± 38.997 ° and proceeds in the direction of the front surface portion 8 and the direction of the back surface portion 9, so that when the optical element 20 is provided on the front surface portion 8, When the same configuration as described is used, a light guide plate 2 used for a front light can be obtained. Further, the emitted light can be freely controlled by selecting the angle of the inclined surface of the optical element 20 so that the light beam once totally reflected by the front surface portion 8 is again totally reflected by the back surface portion 9 again.
[0085]
  Further, by forming an arc inward or outward with the central portion of the inclined surface 21 or the inclined surface 22 of the optical element 20 as the center, the emission position within the light guide plate 2 of the same size is set to the inclined surface 21 or the inclined surface 22. When the inner side of the surface is an arc, it can be brought closer to the light source side, and when the outer side of the inclined surface 21 or the inclined surface 22 is an arc, it can be moved away from the light source side.
[0086]
  In addition, when the outer surface of the inclined surface 21 or the inclined surface 22 is an arc, the totally reflected light becomes parallel light when the light source 3 or the light source 4 is close, and the total reflection when the light source 3 or the light source 4 is far away. Diffused light can be diffused.
[0087]
  Furthermore, when the inside of the inclined surface 21 or the inclined surface 22 is an arc, the totally reflected light becomes parallel light when the light source 3 or the light source 4 is close, and the total reflection when the light source 3 or the light source 4 is far away. The collected light can be collected.
[0088]
  Also, two inclined arcs 21 and 22 on the optical element 20 are provided on one inclined surface, for example, close to the surface portion 8 and the back surface portion 9 of the inclined surface 21 or the inclined surface 22. By forming an arc in the inner direction at the location and an arc in the outer direction at a location far from the front surface portion 8 and the back surface portion 9, it is possible to obtain two different light collection and diffusion effects on one inclined surface. it can.
[0089]
  As shown in FIG. 2 (similar to FIG. 1), when the light source 3 is a line such as a CCFL (cold cathode tube), the optical element 20 has a brightness near the CCFL (cold cathode tube) electrode. Therefore, the luminance distribution is uniform except for both ends, and both ends are attenuated, so that the distribution corresponds to this. That is, the optical elements 20 at both end portions are extremely close to the incident portion 7, and the pitch of the optical elements 20 becomes finer as the reflection end surface portion 10 facing the incident portion 7 is closer. Distributed.
  10 is the same as FIG.Light ofAn optical element 20 'in which the optical element 20 is discontinuously separated isConnected in seriesIs distributed.
[0090]
  As shown in FIG. 3, when the light source 3b has an L (L) shape such as a CCFL (cold tube), the optical element 20 has a lower luminance near the electrode of the CCFL (cold tube) than the others. The luminance distribution is the highest in the vicinity of the end 60 where the two side surfaces 11 of the light guide plate 2 near the light source 3b intersect with each other, and the vicinity of the diagonal connecting the diagonal 6a with the end 60 is brighter than the vicinity of the side surfaces 11. Since the distribution is high, the distribution corresponds to this. That is, the optical elements 20 near both ends of the light source 3b are extremely close to the incident portion 7, and the pitch of the optical elements 20 near the diagonal connecting the diagonal 6a from the vicinity of the end 60 where the two side surfaces 11 of the light guide plate 2 intersect is rough. In the vicinity of the end 6 facing the incident portion 7, the distribution is particularly dense.
  FIG. 13 is the same as FIG.Light ofAn optical element 20 'in which the optical element 20 is discontinuously separated isConnected in seriesIs distributed.
[0091]
  As shown in FIG. 4, when the light source 4 is a point light source such as a semiconductor light emitting element (LED), the optical element 20 has a particularly high brightness at the center of the semiconductor light emitting element and is attenuated at other than the center. The distribution corresponds to these. That is, the direction in which the luminance distribution is strong is the diagonal 6a direction of the incident portion 5 of the light guide plate 2, and the pitch of the optical elements 20 is finer as the diagonal 6a is approached, and the end 6 has a finer pitch and distribution than the diagonal. It is provided.
  11 is the same as FIG.Light ofAn optical element 20 'in which the optical element 20 is discontinuously separated isConnected in seriesIs distributed.
[0092]
  As shown in FIG. 5, when the light source 4 is a point-like multiple light source such as a semiconductor light emitting device (LED), the optical element 20 has a particularly high luminance at the center of the semiconductor light emitting device because the light source 4 is a semiconductor light emitting device. Since it is high and the area other than the center is attenuated, the distribution corresponds to these. That is, the (radial) incident portion 5 is provided on one side surface of the light guide plate 2, the direction in which the luminance distribution is strong is set as the side surface direction opposite to the light guide plate 2, and the optical element 20 is in the direction of both ends of the light source 4. The pitch and the distribution are finely provided as the end portion 6 is approached.
  12 is the same as FIG.Light ofAn optical element 20 'in which the optical element 20 is discontinuously separated isConnected in seriesIs distributed.
[0093]
  As shown in FIG. 6, when the light source 4b has an array shape in which a plurality of point-like objects such as semiconductor light emitting elements (LEDs) are arranged, the optical element 20 emits semiconductor light since the light source 4b is a semiconductor light emitting element. The center of the element has particularly high luminance, and the other areas are attenuated, so the distribution corresponds to these. That is, the incident portion 5 is provided on one side surface of the light guide plate 2, the direction in which the luminance distribution is strong is the reflection end surface portion 10 opposite to the incident portion 5 of the light guide plate 2, and the optical element 20 is between the adjacent light sources 4 b. The position and the wave shape are close to the incident portion 5, and the pitch and distribution are finer as it approaches the reflection end face portion 10, and the pitch and distribution are finer as it approaches the center between the light sources 4 b adjacent to each other.
[0094]
  As shown in FIG. 7, in the case where the light source 4 is a point light source such as a semiconductor light emitting element (LED), the optical element 20 has a particularly high luminance at the center of the semiconductor light emitting element because the light source 4 is a semiconductor light emitting element. Since it is high and the areas other than the center are attenuated, the distribution corresponds to these. That is, the incident portions 5 are provided at the four corners of the light guide plate 2, the direction in which the luminance distribution is strong is the central direction of the light guide plate 2, and the optical element 20 is pitched and distributed between the adjacent light sources 4 and closer to the central direction. Is provided finely.
[0095]
  As shown in FIG. 8, when the light source 4 is a point light source such as a semiconductor light emitting element (LED), the optical element 20 has a particularly high luminance at the center of the semiconductor light emitting element because the light source 4 is a semiconductor light emitting element. Since it is high and the areas other than the center are attenuated, the distribution corresponds to these. That is, a circular (or polygonal) incident portion 5 is provided at the center of the light guide plate 2, the direction with a strong luminance distribution is set to the four end portions 6 of the light guide plate 2, and a portion with low luminance approaches the incident portion 5. The optical elements 20 are provided so that the positions where the luminance and the like are equal become a completely continuous circumference, and the pitch and distribution become finer as it approaches the outer circumferential direction of the light guide plate 2.
[0096]
  As shown in FIG. 9, in the case where the light source 4 is a point light source such as a semiconductor light emitting element (LED), the optical element 20 has a particularly high luminance at the center of the semiconductor light emitting element because the light source 4 is a semiconductor light emitting element. Since it is high and the areas other than the center are attenuated, the distribution corresponds to these. That is, a substantially elliptical incident portion 5 is provided in the lower center of the light guide plate 2, the direction with a strong luminance distribution is set to the two upper end portions 6 of the light guide plate 2 and one central lower portion, and a portion with low luminance is incident. The optical element 20 is provided so as to approach the portion 5 and have a position where equal brightness and the like are completely continuous, and the pitch and distribution become finer as it approaches the lower end 6b direction and the outer peripheral direction of the light guide plate 2. .
[0097]
  Although not shown here, even when the light source 3 is in the shape of a U (U) such as a CCFL (cold tube), the luminance of the vicinity of the light source 3 is similarly low, and the side surface portion 11 of the light guide plate 2 without the light source 3 is used. Since only one has the lowest luminance, the optical element 20 becomes denser as it approaches the middle of the opposite electrode from the vicinity of the electrode of the light source 3 as a distribution corresponding to these, and at the bottom of the U-shaped U shape. The optical elements 20 are densely provided at opposing positions.
[0098]
  It should be noted that the front surface portion 8 and / or the back surface portion 9 shown in FIGS.DiscontinuousThe optical element 20 ′ has a density distribution that increases functionally in proportion to the distance from the light source 3 or the light source 4.DiscontinuousOptical element 20 'ProvideThe length can be controlled by increasing or decreasing the light amount of the light source 3 or the light source 4 to control the total reflection amount at the front surface portion 8 or the back surface portion 9, thereby controlling the light amount emitted from the light exit surface.
[0099]
  The optical element 20 has a triangular, trapezoidal, and arc-shaped cross section, and has a continuous concave shape or convex shape that ends at the end of the light guide plate 2 having a base width of about 4 μm to 100 μmm, for example. Can be configured.
[0100]
  Similarly, the optical element 20 has a triangular shape, a trapezoidal shape, and an arc-shaped cross section, for example, has a concave shape or a convex shape having a base width of about 4 μm to 100 μmm, and the surface portion 8 of the light guide plate 2 or the like. At the position corresponding to the luminance and light energy distribution of the light source 3 and the light source 4 on the back surface 9DiscontinuousIt can be set as the structure provided in.
[0101]
  Like this,Continuous optical element 20 and discontinuous optical element 20 'The front surface portion 8 and the back surface portion 9 of the light guide plate 2Set inThe light beams entering the light guide plate 2 from the light sources 3, 3b, 4 and 4b are totally reflected by the inclined surfaces of the optical elements 20 and 20 ′, and the directivity and energy of the same light quantity are continuously or at any position. The light can be emitted discontinuously. Moreover, it shows in FIG. 10 thru | or FIG. 12 by the target luminance balance etc.DiscontinuousThe interval between adjacent optical elements 20 'may be controlled.
[0102]
  Further, as shown in FIG. 15, the first light deflection element 30 is placed on the back surface portion 9 of the light guide plate 2.Continuous optical element 20 or discontinuous optical element 20 'The first light deflecting element 30 having a concave shape finer than the optical element 20 can be provided between the columns.
[0103]
  The first light deflection element 30 is formed to be finer than the optical element 20 such that the height is in the range of 1 μm to 4 μm and the maximum width is in the range of 4 μm to 16 μm. For this reason, the amount of light deflected by the first light deflection element 30 is extremely smaller than the amount of light totally reflected by the optical element 20. As a result, since only a part of the light beam emitted from the entire light guide plate 2 is disturbed and only a part of the light beam is disturbed, the luminance is not lowered from an arbitrary viewing angle, and is not easily viewed. Does not happen.
[0104]
  For example, the light beam L0 from the incident portion 7 of the light guide plate 2 enters the light guide plate 2 in the range of the refraction angle α = ± 42.38 ° in the case of acrylic resin, and faces the rear surface portion 9 in the direction of the optical element 20. , The light beam LL totally reflected by the inclined surface of the optical element 20 proceeds in the direction of the surface portion 8.
[0105]
  In addition, theseContinuousOptical element 20Or discontinuous optical element 20 'The light beam LL totally reflected by the inclined surface is a plurality of rows with regularity.Continuous optical element 20 and discontinuous optical element 20 'Therefore, the outgoing light beam LL0 emitted from the surface portion 8 is also uniformly emitted in the same direction. Thereby, generation of a visible spectrum due to light dispersion appears on the exit surface like a rainbow.
[0106]
  However, according to the configuration of the light guide plate 2 of this example, a part of the light beam L0 directed toward the back surface portion 9 reaches the arc-shaped first light deflection element 30 having a diameter in the range of 4 μm to 16 μm.
[0107]
  Since the first light deflecting element 30 is much smaller than the optical element 20, the inclined surface of the first light deflecting element 30 is different from the inclined surface of the optical element 20 with respect to the light ray L0 entering at the same angle. Since the angle formed between the inclined surface and the back surface portion 9 is large, the light beam L3 totally reflected at an angle different from the angle at which the optical element 20 is totally reflected (the total reflection angle is smaller than that of the optical element 20) is directed toward the surface portion 8. Then, the outgoing light beam L30 is emitted from the surface portion 8 at an outgoing angle different from that of the outgoing light beam LL0 from the optical element 20.
[0108]
  Therefore, the visible light spectrum generated by a large number of outgoing light beams LL0 in the same direction with the same brightness appearing on the front surface portion 8 by the optical element 20 by the outgoing light beam L30 emitted from the surface portion 8 by the first light deflection element 30. Disturb regularity and make the visible spectrum inconspicuous.
[0109]
  However, in reality, the visible spectrum is not lost, but when viewed from the exit surface side (outside of the surface portion), it is visible due to the presence of the output light beam L30 (diffused light when viewed from the output light beam LL0) by the first light deflection element 30. The continuity of the spectrum is lost and the visible spectrum cannot be recognized.
[0110]
  Further, although not shown, the angle of the inclined surface of the first light deflecting element 30 is different from the inclined surface of the optical element 20, so that light beams having different incident angles are totally reflected from the optical element 20 at the position of the surface portion 8. Although the light beam reaches the same position as the light beam, the incident angle of the optical element 20 and the first light deflection element 30 on the surface portion 8 is different. Disturb the sex and make the visible spectrum inconspicuous.
[0111]
  Further, the first light deflection element 30 is not only totally reflected, but also refraction and the light beam that has passed through the first light deflection element 30 and exited from the back surface portion 9 is incident again and proceeds in a different direction. Disturb the sex and make the visible spectrum inconspicuous.
[0112]
  Furthermore, as shown in FIG. 16, when the optical element 20 is concave, the light beam L 0 in the light guide plate 2 is totally reflected once by the mirror surface of the light guide plate 2, and then the reflected light is concave air of the optical element 20. When exiting to the layer, a visible spectrum (rainbow) appears in the air layer by Newton prism spectroscopy as shown in FIG. 16 (a), and this visible spectrum is a concave arc bottom (upper part) as shown in FIG. 16 (b). ), The light is refracted and spreads further in the direction of the surface portion 8 of the light guide plate 2 and emits a visible spectrum (rainbow) as light rising upward from the surface portion 8.
[0113]
  However, according to the configuration of this example, as shown in FIG. 17, the light beam L30 in the light guide plate 2 is reflected by the mirror surface of the light guide plate 2 by providing the first light deflection element 30 in the vicinity of the optical element 20. Once totally reflected, the reflected light is totally reflected by the inclined surface of the first light deflection element 30. Then, the totally reflected light beam L31 is again totally reflected at the critical surface of the optical element 20, and this totally reflected light beam L32 travels in the direction of the surface portion 8 of the light guide plate 2. 8 is emitted as light rising upward.
[0114]
  Further, by providing the first light deflecting element 30 in the vicinity of the optical element 20, the light beam L30 in the light guide plate 2 is totally reflected once by the mirror surface of the light guide plate 2, and the reflected light is the first light deflection. Total reflection is performed on the inclined surface of the element 30. As a result, the totally reflected light beam L31 ′ is blocked from traveling toward the optical element 20, travels in the direction of the surface portion 8 of the light guide plate 2, and as light that rises upward from the surface portion 8 as white light without being dispersed. Exit.
[0115]
  In this way, when the optical element 20 has a concave shape or the like, the portion where the light guide plate 2 and the concave optical element 20 are connected has two mirror surfaces such as a prism shape. Total reflection is performed on the mirror surface of the light guide plate 2. Thereafter, when the totally reflected light is emitted to the concave air layer of the optical element 20, a visible spectrum (rainbow) appears in the air layer by Newton prism spectroscopy. However, according to the configuration of this example, the light totally reflected by the mirror surface of the light guide plate 2 is totally reflected by the first light deflecting element 30 and is prevented from proceeding to the optical element 20, so that the visible spectrum (rainbow) Occurrence can be prevented.
[0116]
  Further, the generation of the visible spectrum (rainbow) as described with reference to FIG. 16 refracts at the concave portion and further spreads toward the surface portion 8 of the light guide plate 2, and the visible spectrum (rainbow) moves upward from the surface portion 8. stand up. However, as described with reference to FIG. 15, the regularity of the visible spectrum is disturbed by the totally reflected light from the first light deflection element 30, so that the visible spectrum can be made inconspicuous.
[0117]
  In addition to the above, a part of the light beam L0 is totally reflected by the back surface portion 9, and the totally reflected light reaches the front surface portion 8 and repeats total reflection again to reach the optical element 20 and the like. Since this ray is a repetition of total reflection, the approach angle with respect to the optical element 20 is the same as that of the ray L0, and the ray reaching the optical element 20 or the first light deflection element 30 obtains the functions and effects described above. .
[0118]
  Further, although not shown in the figure, light rays that have entered the light guide plate 2 from the end portion 7 ′ of the front surface portion 8 and the back surface portion 9 connected to the incident portion 7 of the light guide plate 2 are repeatedly totally reflected by the front surface portion 8 and the back surface portion 9.AccompanyingBright and dark light having different brightness reaching the exit surface due to interference is periodically generated like a stripe pattern.
[0119]
  Further, the light emitted from the optical element 20 can be made bright and dark by direct light from the optical element 20 depending on the directivity and brightness of the light source 3 together with the optical element 20, and a stripe pattern of bright and dark light may be generated.
[0120]
  However, according to the configuration of this example, the regularity of the bright and dark light generated on the emission surface by the outgoing light L30 emitted to the front surface portion 8 and the back surface portion 9 by the first light deflecting element 30 is disturbed, so Generation of stripes can be prevented.
[0121]
  Here, the first light deflecting element 30 has been described as an arc-shaped concave shape with a diameter ranging from 4 μm to 16 μm, but a conical shape and a height ranging from 1 μm to 4 μm and a maximum width ranging from 4 μm to 4 μm. A polygonal pyramid shape in the range of 16 μm may be used. Even in this case, as described above, if the light beam that has been refracted or totally reflected is emitted to the place where the light beam totally reflected from the optical element 20 exists, the same operation and effect can be obtained.
[0122]
  Further, the first light deflection element 30 generates a visible spectrum (rainbow) with higher luminance as it is closer to the incident portion 7 of the surface portion 8 when the luminance of the light source 3 is strong or the light source 3 has high directivity. And it becomes more noticeable. For this reason, the closer to the incident portion 7 of the back surface portion 9, the more first light deflection elements 30 are provided. Thereby, generation | occurrence | production of a visible spectrum (rainbow) can be disturbed, and a visible spectrum (rainbow) can be made not conspicuous.
[0123]
  Further, the first light deflection element 30 is randomly provided on the back surface portion 9 depending on the luminance of the light source 3 and the size of the light guide plate 2. Thereby, generation | occurrence | production of the visible spectrum (rainbow) from the whole light-guide plate 2 can be disturbed, and a visible spectrum (rainbow) can be made inconspicuous.
[0124]
  As described above, the first light deflection element 30 has a visible spectrum (rainbow) due to the optical element 20 itself (due to the regular existence of the optical element 20 and the like) corresponding to the conditions and specifications of the light source 3 and the light guide plate 2 and the purpose of use. ) And the occurrence of bright and dark light stripes due to the regularity of light caused by the incident portion 7 can be prevented.
[0125]
  In the description here, the first light deflection element 30 and the optical element 20 are provided on the back surface portion 9 of the light guide plate 2, but the first light deflection element 30 may be provided on the front surface portion 8. These operations and effects are also the same as in the case where the back surface portion 9 is provided, and therefore the description of providing the light deflecting element 30 on the front surface portion 8 is redundant and will be omitted.
[0126]
  Although the shape of the first light deflecting element 30 has been described here as a fine concave shape, the function and effect are the same even with a fine convex shape. The description of 30 is omitted because it overlaps.
[0127]
  Further, in particular, the first light deflecting element 30 and the optical element 20 can be provided on the front surface portion 8, and the emitted light can be emitted from the direction of the back surface portion 9 to be used for a front light or the like.
[0128]
  Further, although not shown in the drawing, the light guide plate 2 is closely attached to the light guide plate 2 with the diffusion sheet or the like provided near the front surface portion 8 or the back surface portion 9 or the reflector 15 or the reflection case below the back surface portion 9. It can be prevented by the light deflection element 30 and the effect of a diffusion sheet or the like can be brought out. Further, the convex first light deflecting element 30 keeps an air layer between the light guide plate 2 and the reflector 15 or the reflection karate, and directly passes the surface of the reflector 15 or the reflection case through the (white) light guide plate 2. You can hide it.
[0129]
  In addition, as shown in FIG. 18, the light guide plate 2 is configured so that the light incident on the light guide plate 2 from the end portion 7 ′ of the front surface portion 8 and the back surface portion 9 connected to the incident portion 7 of the light guide plate 2 is particularly incident. Between the front surface portion 8 and the back surface portion 9 between the reflection end surface portion 10 located on the opposite side of the incident portion 7AccompanyingBright and dark light with different brightness is generated by interference. Then, as shown in FIG. 19, when a light beam with brightness and darkness reaches the optical element 20 provided on the back surface portion 9, it is deflected by the optical element 20 and a part of the light emitted from the front surface portion 8 is minutely refracted. By providing the second light deflecting element 40, the bright and dark light stripes composed of regular bright and dark light are made inconspicuous.
[0130]
  The second light deflection element 40 is formed in a circular arc shape with a diameter in the range of 5 μm to 100 μm and a gentle arc shape with a small number of protrusions in the range of 1/20 to 1/80 of the diameter and a large curvature radius. . For this reason, the light beam totally reflected by the optical element 20 does not change the exit angle extremely even if it is refracted when entering and exiting the second light deflecting element 40, and is slightly refracted partially on the light guide plate 2. Therefore, it does not cause a decrease in luminance from an arbitrary viewing angle, and it does not become so difficult to see.
[0131]
  For example, the light beam L0 from the incident portion 7 of the light guide plate 2 enters the light guide plate 2 in the range of the refraction angle α = ± 42.38 ° in the case of acrylic resin, and is particularly guided as shown in FIG. A light beam incident on the light guide plate 2 from the end portion 7 ′ of the front surface portion 8 and the back surface portion 9 connected to the incident portion 7 of the optical plate 2 is formed between the incident portion 7 and the reflection end surface portion 10 located on the opposite side of the incident portion 7. Between the front surface portion 8 and the back surface portion 9, the incident portion 7 and the reflection end surface portion 10 are repeatedly totally reflected.AccompanyingBright and dark light with different brightness is generated by interference. Then, as shown in FIG. 19, a light beam having brightness and darkness, a light beam directly directed from the incident portion 7 toward the back surface portion 9 and a light beam L0 subjected to repeated total reflection in the light guide plate 2 is applied to the optical element 20. The light beam LL totally reflected by the inclined surface of the optical element 20 travels in the direction of the surface portion 8.
[0132]
  Then, the light itself traveling uniformly in the same direction by the optical element 20 contains brightness and darkness, and the emitted light beam LL0 emitted from the surface portion 8 is also emitted uniformly in the same direction, and the light and dark light by the bright and dark light on the exit surface. The occurrence of stripes appears.
[0133]
  In addition, the emitted light can be made bright and dark by direct light from the optical element 20 depending on the directivity and brightness of the light source 3 and the light source 4 together with the optical element 20, and a stripe pattern of bright and dark light may be generated.
[0134]
  However, according to the configuration of this example, the light beam LL4, which is a part of the light beam LL that is totally reflected by the inclined surface of the optical element 20 and travels in the direction of the surface portion 8, reaches the second light deflection element 40, and the second When the light beam is emitted from the light deflecting element 40, the arc shape is gentle (because the difference between the normal line of the second light deflecting element 40 and the normal line of the surface portion 8 of the light guide plate 2 is small). Refract. Thereby, the outgoing light beam L40 is emitted from the surface portion 8 at a slightly different outgoing angle from that of the outgoing light beam LL0 from the optical element 20. In FIG. 19, the locus of the outgoing light beam when the second light deflection element 40 is not provided is indicated by a dotted line LL0 '.
[0135]
  In this way, the second light deflection element 40 emits the outgoing light beam L40 at a slightly different outgoing angle from the outgoing light beam LL0 from the optical element 20 to the surface portion 8, so that regular bright and dark light is emitted as the outgoing light beam L40. It is possible to prevent the generation of bright and dark light stripes having periodicity.
[0136]
  Although the first light deflection element 30 has been described, these optical elements 20And optical element 20 'The light beam LL totally reflected by the inclined surface is a plurality of rows with regularity.Continuous optical element 20 or discontinuous optical element 20 'Therefore, the outgoing light beam LL0 emitted from the surface portion 8 is also emitted in the same direction, and a visible spectrum (rainbow) due to the light spectrum appears on the emission surface like a rainbow.
[0137]
  However, according to the configuration of the present example, the emitted light beam L40 emitted from the second light deflecting element 40 has the same level of brightness that appears on the surface portion 8 in the optical element 20 and has a large number of outgoing lights in the same direction. The regularity of the visible spectrum (rainbow) generated by the light beam LL0 is disturbed to make the visible spectrum (rainbow) inconspicuous.
[0138]
  However, the visible spectrum (rainbow) is not actually lost, but when viewed from the exit surface side (outside of the surface portion), the output light L40 (diffused light when viewed from the output light L0) by the second light deflection element 40 is used. The existence of the visible spectrum loses its continuity and the visible spectrum (rainbow) cannot be recognized.
[0139]
  In addition to the above, although not shown, some of the light rays refracted and incident on the light guide plate 2 and directly incident on the second light deflecting element 40 directly toward the front surface portion 8 and the light beam L0 are totally reflected by the back surface portion 9. The light beam that has directly reached the second light deflecting element 40 toward the surface portion 8 also obtains the functions and effects described above.
[0140]
  Further, the second light deflection element 40 is randomly provided on the surface portion 8 according to the luminance of the light source 3 or the light source 4, the size of the light guide plate 2, or the like. As a result, the generation of the visible spectrum (rainbow) from the entire light guide plate 2 is disturbed by the outgoing light beam L40 to make the visible spectrum (rainbow) inconspicuous, or the rule of the stripe pattern of bright and dark light generated from the entire light guide plate 2 The property can be disturbed by the outgoing light beam L40 and the striped pattern can be made inconspicuous.
[0141]
  The second light deflection element 40 has a visible spectrum (rainbow) with a higher luminance as it is closer to the incident portion 7 of the surface portion 8 when the luminance of the light source 3 or the light source 4 is strong or the light source 4 is more directional. ) Occurs and becomes more noticeable. For this reason, the closer to the incident portion 7 of the surface portion 8, the more second light deflection elements 40 are provided. Thereby, generation | occurrence | production of a visible spectrum (rainbow) can be disturbed, and a visible spectrum (rainbow) can be made not conspicuous.
[0142]
  Further, in the second light deflection element 40, the incident portion 7 closer to the light source 3 or the light source 4 has a higher brightness of the total reflected light from the optical element 20, so that the closer to the incident portion 7, the brighter and darker the emitted light that appears on the emission surface. When the image is conspicuous, brighter and darker light is generated and becomes more conspicuous as the surface portion 8 is closer to the incident portion 7. For this reason, the closer to the incident portion 7 of the surface portion 8, the more second light deflection elements 40 are provided. Thereby, the generation of bright and dark light can be disturbed to make the bright and dark light inconspicuous.
[0143]
  Thus, the second light deflection element 40 is visible by the optical element 20 itself (due to the regular presence of the optical element 20 and the like) corresponding to the conditions and specifications of the light source 3, the light source 4, and the light guide plate 2 and the purpose of use. Generation of a spectrum (rainbow) and bright / dark light can be prevented.
[0144]
  In the description here, the second light deflection element 40 and the optical element 20 are provided on the front surface portion 8 of the light guide plate 2, but the second light deflection element 40 may be provided on the back surface portion 9. Since these operations and effects are also the same as those provided on the front surface portion 8, the description of providing the second light deflection element 40 on the back surface portion 9 is redundant and will be omitted.
[0145]
  Furthermore, although the shape of the second light deflecting element 40 has been described as a convex shape here, these actions and effects are also the same depending on the concave shape, and therefore the description of the concave second light deflecting element 40 is duplicated. I will omit it.
[0146]
  In particular, the second light deflecting element 40 can be provided on the back surface portion 9 and the optical element 20 on the front surface portion 8, and the emitted light can be emitted from the direction of the back surface portion 9 to be used for a front light or the like.
[0147]
  Thus, the position corresponding to the luminance distribution or light energy distribution of the light source 3 or the light source 4 on the front surface portion 8 or the rear surface portion 9 of the light guide plate 2.LightIt has an inclined surface corresponding to the light flux from the light source 3 and the light source 4Continuous optical element 20 or discontinuous optical element 20 'Is applied to the density distribution that increases functionally in proportion to the distance from the light source 3 and the light source 4 so that the brightness and energy from the light source 3 and the light source 4 are always equal.Continuous optical element 20 or discontinuous optical element 20 'The side of the exit surface that undergoes total reflection and refraction by the inclined surfaceSame asIt is possible to emit the same brightness and energy.
[0148]
  Further, every position of the light guide plate 2 so that the density distribution of the optical element 20 increases functionally in proportion to the distance from the light source 3 or the light source 4 as the luminance or energy from the light source 3 or the light source 4 is attenuated. However, the product of the quantity of emitted light and its solid angle can be made equal.
[0149]
  Further, the desired luminance distribution of the light guide plate 2 can be expressed by obtaining light energy lower than that where the optical element 20 is present at the location where the optical element 20 is missing.
[0150]
  Furthermore, the optical element 20Or discontinuous optical element 20 'The first light deflector 30 having a finer concave shape or convex shape is formed.Continuous optical element 20 and discontinuous optical element 20 'Between the two rows. This allows multiple columnsContinuous optical element 20 and discontinuous optical element 20 'The generation of a visible spectrum due to the spectrum of light appearing on the emission surface can be prevented without lowering the emission luminance by the diffraction grating element, the Newton prism spectral element, or the white light source 4 with particularly strong directivity. In addition, depending on the directivity and brightness of the light source 3 and the light source 4, the direct light from the optical element 20 causes the brightness of the emitted light, and the generation of a stripe pattern due to the light and dark light due to repeated total reflection at the front surface portion 8 and the back surface portion 9. In contrast, the emission luminance can be prevented without being lowered.
[0151]
  Further, light rays that have entered the light guide plate 2 from the end portions of the front surface portion 8 and the back surface portion 9 connected to the incident portion 7 of the light guide plate 2 are repeatedly totally reflected by the front surface portion 8 and the back surface portion 9.AccompanyingA second light deflecting element 40 is provided that minutely refracts a part of periodic bright and dark light beams having different luminances that reach the exit surface due to interference. Thereby, generation | occurrence | production of the periodic stripe pattern of the bright and dark light by the brightness of light can be prevented, without reducing an emitted luminance. Moreover, the optical element 20 slightly refracts a part of the visible spectrum generated by a large number of outgoing light beams in the same direction having the same brightness, and the continuity of the outgoing light is disturbed. Can be prevented without lowering the emission luminance.
[0152]
  Further, as shown in FIG. 21, the vicinity of the front surface portion 8 by the second light deflection element 40 provided on the front surface portion 8 of the light guide plate 2 and the convex first light deflection element 30 provided on the back surface portion 9. It is possible to prevent the light guide plate 2 from being in close contact with the reflector 15, the reflective case, and the like provided in the vicinity of the diffusion sheet 16 and the back surface portion 9 provided on the back surface 9. In addition, since the air layer is present between the diffusion sheet 16 and the light guide plate 2 by the convex first light deflection element 30, the light emitted from the light guide plate 2 does not travel into the diffusion sheet 16 as it is. Once the refractive index of the light guide plate 2 is changed, the emission angle can be changed to bring out the effect of the diffusion sheet 16.
[0153]
  If there is no air layer between the diffusion sheet 16 and the reflector 15, the surface of the diffusion sheet 16 or the reflector 15 is made to be integrated with the light guide plate 2 (for example, white). It can be seen directly through the light guide plate 2 (for example, the type on the paper sheet placed under the flat glass is observed as it is). However, according to the configuration of this example, the diffusion sheet 16 and the reflector are provided by providing the second light deflection element 40 on the front surface portion 8 of the light guide plate 2 and the convex first light deflection element 30 on the rear surface portion 9. An air layer can be secured between 15 and the light guide plate 2. Thereby, it is possible to prevent the surfaces of the diffusion sheet 16 and the reflector 15 from being directly seen through the light guide plate 2.
[0154]
  The light source 3 has a linear shape such as a CCFL (cold tube), direct light is incident on the light guide plate 2 from the incident portion 7 of the light guide plate 2, and the other light is reflected by the reflector 14 while being reflected by the light source 3 and the reflector. 14 enters the light guide plate 2 through the space.
[0155]
  In addition to the linear CCFL, the light source may be a semiconductor light emitting element or an array of semiconductor light emitting elements as shown in FIGS.
[0156]
  For example, the light source 4 shown in FIGS. 4 and 5 is a semiconductor light emitting element, and includes an LED, a laser, and the like, and performs wavelength conversion using monochromatic light, white (RGB, red, green, blue) or a fluorescent material. Also used is white light.
[0157]
  Further, when the light guide plate 2 has a plurality of incident portions 5 at the corner 6 where the two side surface portions 11 intersect with each other, a light source 4 having a different light emission color is used for each incident portion to generate white light from the entire light guide plate 2. May be emitted.
[0158]
  Furthermore, as in the light source 4b shown in FIG. 6, it is possible to use a semiconductor light emitting element in which the semiconductor light emitting elements are arranged in an array with equal intervals or densely arranged at both end portions and integrated with a resin or the like.
[0159]
  The reflector 14 is made of a white insulating material or a sheet or metal on which a metal such as aluminum is deposited, and surrounds the incident portion 7 of the light guide plate 2, the light source 3, the light source 4, and the light source 4b. The light from the light source 4 and the light source 4 b is reflected, and the reflected light is incident again on the incident portion 7 of the light guide plate 2.
[0160]
  Although not shown, the light source 3, the light source 4, and the light source 4 b are surrounded by the same material so that the incident portion 7 of the light guide plate 2 and the light source 3, the light source 4, and the light source 4 b are surrounded. The light from the light source 4 b is reflected, and the reflected light is incident again on the incident portion 7 of the light guide plate 2.
[0161]
  The reflector 15 is made of a sheet obtained by depositing metal such as aluminum on a sheet in which a white material such as titanium oxide is mixed in a thermoplastic resin or a sheet of a thermoplastic resin, or by laminating metal foil. The reflector 15 covers the portion other than the incident portion 7 and the incident portion 7 and the surface portion 8 and reflects or reflects light other than light emitted from the light source 3, the light source 4, and the light source 4 b to the surface portion 8 by the light guide plate 2. The light is diffusely reflected and again incident on the light guide plate 2 so that all the light from the light source 3, the light source 4, and the light source 4 b is emitted from the surface portion 8.
[0162]
  The flat illumination device is not provided with a correction sheet for finally controlling the distribution of light rays and the like above the light guide plate 2, but a correction sheet may be used if necessary. This correction sheet is made of a transmissive resin or the like, and has an uneven surface for deflecting light on the surface. This correction sheet corrects the emitted light from the light guide plate 2, diffuses the emitted light with high luminance, collects the emitted light with low luminance, scatters the whole, or partially diffuses. Condensing light. Therefore, select a diffusion sheet, condensing sheet, scattering sheet, diffusing condensing sheet, etc. that should be corrected according to the purpose, and use it by using the processed surface in the forward or reverse direction. To do.
[0163]
【The invention's effect】
  As described above, in the light guide plate according to claim 1, the front surface portion and / or the back surface portion corresponds to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceInstall continuously and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightSince the first light deflection element having a concave shape and / or convex shape that is finer than the optical element is provided between the rows of the optical elements, the luminance and energy from the light source are always equal.LightPerforms total reflection and refraction by the inclined surface of the optical element, and exit sideSame asIt is possible to emit the same brightness and energy. Moreover, the product of the amount of light emitted at every position of the light guide plate and its solid angle is equal so that the density distribution of the optical element increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. Can be emitted. In addition, a highly directional white light source and multiple rowsLight ofSince the first light deflecting element can diffuse a part of the light beam from the light source to the optical element by generating the light spectrum (rainbow) appearing on the exit surface by the diffraction grating element by the optical element, the visible spectrum ( The continuity of the rainbow is lost (disturbed), the recognition of the visible spectrum (rainbow) is disturbed, and the generation of the visible spectrum (rainbow) on the exit surface can be prevented without lowering the exit brightness.
[0164]
  Also, in the case of a concave optical element, the visible spectrum (rainbow) that appears by Newton prism spectroscopy when the part where the light guide plate and the concave optical element are connected has two mirror surfaces such as a prism shape, It is possible to prevent the light beam traveling to the element from being totally reflected by the first light deflecting element and proceeding to the optical element, thereby preventing the generation of the visible spectrum (rainbow).
[0165]
  Furthermore, with a convex first light deflecting element provided on the front surface portion or the back surface portion of the light guide plate, a diffusion sheet or the like provided near the front surface portion or the back surface portion, a reflector or case below the back surface portion, etc. Since adhesion to the light guide plate can be prevented, the intended effect can be easily obtained without impairing the original functions of the diffusion sheet, the reflector, the reflection case, and the like. Moreover, it is possible to obtain easy-to-see outgoing light without directly observing the diffusion sheet, the reflector, the reflection case, and the like.
[0166]
  In the light guide plate according to claim 2, the front surface portion and / or the back surface portion corresponds to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceDiscontinuous installation and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightSince the first light deflection element having a concave shape and / or convex shape that is finer than the optical element is provided between the rows of the optical elements, the luminance and energy from the light source are always equal.LightPerforms total reflection and refraction by the inclined surface of the optical element, and exit sideSame asIt is possible to emit the same brightness and energy. Moreover, the product of the amount of light emitted at every position of the light guide plate and its solid angle is equal so that the density distribution of the optical element increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. Can be emitted. Moreover,DiscontinuousHowever, by controlling the length of the optical element and the distance between adjacent optical elements, the product of the amount of light emitted from the optical element is equal to the solid angle, but there is no optical Light energy lower than that of the element can be obtained. In addition, a highly directional white light source etc. and multiple rowsLight ofSince the first light deflecting element can diffuse a part of the light beam from the light source to the optical element by generating the light spectrum (rainbow) appearing on the exit surface by the diffraction grating element by the optical element, the visible spectrum ( The continuity of the rainbow is lost (disturbed), the recognition of the visible spectrum (rainbow) is disturbed, and the generation of the visible spectrum (rainbow) on the exit surface can be prevented without lowering the exit brightness.
[0167]
  Also, in the case of a concave optical element, the visible spectrum (rainbow) that appears by Newton prism spectroscopy when the part where the light guide plate and the concave optical element are connected has two mirror surfaces such as a prism shape, It is possible to prevent the light beam traveling to the element from being totally reflected by the first light deflecting element and proceeding to the optical element, thereby preventing the generation of the visible spectrum (rainbow).
[0168]
  Furthermore, with a convex first light deflecting element provided on the front surface portion or the back surface portion of the light guide plate, a diffusion sheet or the like provided near the front surface portion or the back surface portion, a reflector or case below the back surface portion, etc. Since adhesion to the light guide plate can be prevented, the intended effect can be easily obtained without impairing the original functions of the diffusion sheet, the reflector, the reflection case, and the like. Moreover, it is possible to obtain easy-to-see outgoing light without directly observing the diffusion sheet, the reflector, the reflection case, and the like.
[0169]
  Furthermore, the light guide plate according to claim 3 is provided with a larger number of first light deflecting elements on the front surface portion and / or back surface portion as it is closer to the random or incident portion, and the height is in the range of 1 μm to 4 μm and the maximum width is 4 μm. Since it is a polygonal pyramid shape in the range of ˜16 μm or a circular arc shape or a conical shape in the range of 4 μm to 16 μm, it is finer than the optical element, and therefore has a great influence on the emitted light by the first light deflection element. Instead, the light emitted from the optical element can be controlled by the deflected light beam from the first light deflecting element. Also, multiple rows for white light source with strong directivity or high brightnessLight ofWhen the generation of a visible spectrum (rainbow) due to light spectroscopy appears on the exit surface in the vicinity of the incident portion due to the diffraction grating element of the optical element, the first light deflection element is placed on the incident portion on the front surface portion and / or the back surface portion. It is possible to diffuse more part of the light beam from the light source toward the optical element or to emit light beams having different emission angles on the emission surface as the closer they are provided. Thereby, generation | occurrence | production of the visible spectrum (rainbow) of an output surface can be prevented, without reducing an emitted luminance, and it can utilize irrespective of the kind of light source, or the shape of a light-guide plate.
[0170]
  In addition, when the white light source has a weak directivity, the light incident on the light guide plate from the end of the front and back surfaces connected to the incident portion of the light guide plate is repeatedly totally reflected on the front and back surfaces.AccompanyingA part of light emitted from bright and dark lights having different luminance due to interference is diffused in a minute amount by partially providing the first light deflection element on the front surface part and / or the back surface part. Can do. Thereby, generation | occurrence | production of the periodic stripe pattern of bright and dark light can be prevented on an output surface, without reducing an emitted luminance.
[0171]
  In the light guide plate according to claim 4, the front surface portion and / or the back surface portion corresponds to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceInstall continuously and optical elementsSurface or back surface facing the optical element with a density distribution that increases functionally in proportion to the distance from the light sourceLightSince the second light deflecting element that minutely refracts part of the light emitted from the optical element is provided, the brightness and energy from the light source are always equal.LightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. Moreover, the product of the amount of light emitted at every position of the light guide plate and its solid angle is equal so that the density distribution of the optical element increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. Can be emitted. In addition, the light incident on the light guide plate from the end of the front and back surfaces connected to the incident portion of the light guide plate is repeatedly totally reflected on the front and back surfaces.AccompanyingA part of bright and dark light beams having different luminances reaching the exit surface due to interference reaches the second light deflection element having a diameter larger than the height (a part of an arc having a large radius of curvature). The light beams emitted from the two light deflecting elements can be emitted at different emission angles that are finer than the flat surface portion. Accordingly, it is possible to prevent the occurrence of a stripe pattern of bright and dark light without causing a slight disturbance of periodic bright and dark light and lowering the emission luminance.
[0172]
  Also, multiple columns with regularityLight ofEven if the light is emitted uniformly in the same direction by the scientific element itself, and the generation of a visible spectrum (rainbow) due to light spectroscopy appears on the exit surface, a part of the visible spectrum (rainbow) is slightly deflected to make the visible spectrum It is also possible to make the visible spectrum (rainbow) inconspicuous by preventing the generation of the visible spectrum (rainbow).
[0173]
  Further, the second light deflection element provided on the front surface portion or the back surface portion of the light guide plate can prevent the light guide plate from being in close contact with the diffusion sheet provided near the front surface portion or the back surface portion.
[0174]
  Furthermore, in the light guide plate according to claim 5, the front surface part and / or the back surface part is a position corresponding to the luminance distribution or light energy distribution of the light source.LightAn optical element having an inclined surface corresponding to the light flux from the sourceDiscontinuous installation and optical elementsSurface or back surface facing the optical element with a density distribution that increases functionally in proportion to the distance from the light sourceSet inSince the second light deflecting element that minutely refracts part of the light emitted by the optical element is provided, the brightness and energy from the light source are always equal.LightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. Moreover, the product of the amount of light emitted at every position of the light guide plate and its solid angle is equal so that the density distribution of the optical element increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. Can be emitted. in addition,DiscontinuousHowever, by controlling the length of the optical element and the interval between the adjacent optical elements, the product of the amount of light emitted from the optical element and the solid angle can be emitted equally. Furthermore, the light rays that have entered the light guide plate from the end portions of the front surface portion and the back surface portion connected to the incident portion of the light guide plate are repeatedly totally reflected on the front surface portion and the back surface portion.AccompanyingA part of bright and dark light beams having periodicity with different brightness reaching the exit surface due to interference reaches the second light deflection element having a large diameter with respect to the height (so-called part of an arc having a large curvature radius). However, since the light beam emitted from the second light deflecting element is emitted at a slightly different emission angle than the flat surface portion, the brightness of the periodic light is slightly disturbed to reduce the emission luminance. Generation of bright and dark light stripes or the like can be prevented without lowering.
[0175]
  Also, multiple columns with regularityLight ofEven if the light is emitted uniformly in the same direction by the scientific element itself, and the generation of a visible spectrum (rainbow) due to light spectroscopy appears on the exit surface, a part of the visible spectrum (rainbow) is slightly deflected to make the visible spectrum It is also possible to make the visible spectrum (rainbow) inconspicuous by preventing the generation of the visible spectrum (rainbow).
[0176]
  Further, the second light deflection element provided on the front surface portion or the back surface portion of the light guide plate can prevent the light guide plate from being in close contact with the diffusion sheet provided near the front surface portion or the back surface portion.
[0177]
  The light guide plate according to claim 6 has an arc shape with a diameter of the second light deflection element in the range of 5 μm to 100 μm and a height in the range of 1/20 to 1/80 of the diameter. On the other hand, since the diameter is large (a part of a so-called arc having a large radius of curvature), the normal line of the second light deflection element is only slightly different from the normal line of the light guide plate. For this reason, since the difference in the emission angle is also small, it can work effectively against bright and dark light without affecting the luminance distribution of the emitted light, and the second light deflection element itself is inconspicuous.
[0178]
  In addition, since the second light deflecting element is provided on the front surface portion or the back surface portion so as to be random or closer to the incident portion, the light beam incident on the light guide plate from the end portions of the front surface portion and the back surface portion connected to the incident portion of the light guide plate Repeats total reflection on the front and backAccompanyingGeneration of bright and dark light with different luminance due to interference can be prevented by providing the second light deflecting element randomly on the front surface or the back surface. Since the bright and dark stripe pattern is more conspicuous in the vicinity of the portion than in other places, the more light and dark stripe patterns can be prevented by providing more second light deflecting elements closer to the incident portion on the front surface portion or the rear surface portion. Thereby, it can utilize irrespective of the position etc. where a high-intensity light source and a light source are provided.
[0179]
  Furthermore, the light guide plate according to claim 7 has a triangular, trapezoidal, or arc-shaped cross section of the optical element and is continuous or non-continuous, so that light rays that have entered the light guide plate from the incident portion of the light guide plate are triangular. Shaped, trapezoidal, and arcuate inclined surfaces can exist at positions corresponding to the normal of the light from the light source, and if these are continuous, equivalent brightness and energy can be emitted at any position. Even if it is discontinuous, the same brightness and energy can be continuously emitted at any position.
[0180]
  Further, the light guide plate according to the eighth aspect of the invention increases the height of the optical element or / and partially raises or lowers the height of the optical element as the distance from the light source increases. Can be reflected. As a result, a large amount of emitted light can be emitted even at a position far from the light source to obtain a uniform emission luminance from the light guide plate regardless of the distance of the light source, or any position of the light guide plate by partially raising or lowering it. The amount of light emitted from can be increased or decreased, and the angle of light emitted from an arbitrary position of the light guide plate can be changed. For this reason, it is possible to control the luminance and the viewing angle at an arbitrary position of the required light guide plate.
[0181]
  Furthermore, in the light guide plate according to claim 9, since the angle between the inclined surface and the front surface portion and the back surface portion is in the range of π / 2-2 · critical angle to critical angle, the maximum incidence of the light beam guided into the light guide plate By using the range from the angle to the minimum angle that breaks the critical angle, the total reflected light can all break the critical angle. Thereby, since the emission angle range from the emission surface of the light guide plate can be made large, the required emission angle can be freely selected and can be adapted to the purpose.
[0182]
  Further, in the light guide plate according to claim 10, since the angle formed between the front surface portion and the back surface portion in proportion to the distance from the light source approaches the critical angle, even with the attenuation of luminance and energy from the light source, The reflected light totally reflected in proportion to the distance from the light source is emitted at a small emission angle. For this reason, the product of the light quantity emitted and the solid angle can be emitted equally at any position on the emission surface of the light guide plate. Thereby, a uniform emission amount and a uniform viewing angle can be obtained.
[0183]
  Furthermore, since the light guide plate according to claim 11 forms an arc on the inner side or the outer side around the central portion of the inclined surface, or partially on the inner side and the outer side of the inclined surface, When the emission position in the light guide plate of the same size is formed as an arc inside the inclined surface, it can be brought closer to the light source side. Further, when the light source is near, the totally reflected light becomes parallel light, and when the light source is far, the totally reflected light can be collected.
[0184]
  Further, when the emission position in the light guide plate having the same size is formed as an arc on the outer side of the inclined surface, it can be moved away from the light source side. Further, when the light source is near, the totally reflected light becomes parallel light, and when the light source is far, the totally reflected light can be diffused.
[0185]
  In addition, since the inner and outer arcs are partially inclined on one inclined surface and the actions and effects such as condensing and diffusing are obtained on one inclined surface by one different inclined surface, the size of the light guide plate, the required amount of emitted light, The viewing angle can be freely controlled.
[0186]
  The planar illumination device according to claim 12 is a light source, an incident portion that guides light from the light source, and a position corresponding to the luminance distribution or light energy distribution of the light source.LightIt has an inclined surface corresponding to the light flux from the source.The optical elements to be installed continuously and the optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightLight emitted from the optical element to the front surface portion or the back surface portion facing the first optical deflection element or / and the optical element that is finer than the optical element between the rows of the optical elements and finer than the optical element A light guide plate provided with a second light deflection element that slightly refracts a part of the light guide plate, and a reflector that covers the light guide plate other than the incident portion and the exit surface and reflects the leaked light from the light guide plate again into the light guide plate Because it has, the position where the brightness and energy from the light source are always equalLightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. In addition, the density distribution of the optical element increases functionally in proportion to the distance from the light source as the brightness and energy from the light source decay, and the amount of light emitted from any position of the light guide plate and its solid angle It is possible to emit the same product or to freely control the exit angle from the exit surface by setting the angle of the inclined surface.
[0187]
  In addition, a multi-row with a highly directional white light source, etc.Light ofGeneration of light spectrum (rainbow) appearing on the exit surface by the diffraction grating element by the optical element can diffuse a part of the light beam from the light source to the optical element by the first light deflecting element, and the incident of the light guide plate The light incident on the light guide plate from the end of the front and back parts connected to the part repeats total reflection on the front and back parts.AccompanyingA part of bright and dark light beams having periodicity with different brightness and the like that reach the exit surface due to interference is a second light deflection element having a large diameter with respect to the height (so-called part of an arc having a large curvature radius). A light beam that reaches and exits to the outside from the second light deflection element can be emitted at a different exit angle that is finer than that of the flat surface portion. Accordingly, it is possible to prevent the occurrence of bright and dark light stripes or the like without causing a slight hindrance to bright and dark light having periodicity and lowering the emission luminance.
[0188]
  Also, in the case of a concave optical element, the visible spectrum (rainbow) that appears by Newton prism spectroscopy when the part where the light guide plate and the concave optical element are connected has two mirror surfaces such as a prism shape, It is possible to prevent the light beam traveling to the element from being totally reflected by the first light deflecting element and proceeding to the optical element, thereby preventing the generation of the visible spectrum (rainbow).
[0189]
  In addition, regular multiple columnsLight ofEven if the light is emitted uniformly in the same direction by the scientific element itself, and the generation of a visible spectrum (rainbow) due to light spectroscopy appears on the exit surface, a part of the visible spectrum (rainbow) is slightly deflected to make the visible spectrum The regularity of the (rainbow) can be disturbed to prevent the generation of the visible spectrum (rainbow) and make the visible spectrum (rainbow) inconspicuous.
[0190]
  In addition, the convex first light deflecting element and the second light deflecting element provided on the front surface portion and the back surface portion of the light guide plate, and the diffusion sheet provided in the vicinity of the front surface portion and the back surface portion and the lower portion of the back surface portion. It is possible to emit light while preventing adhesion between a light reflector and a certain reflector or reflection case. As a result, it is possible to easily obtain the desired effect without impairing the original functions of the diffusion sheet, the reflector, the reflection case, etc., and to obtain outgoing light that is easy to see without directly observing the diffusion sheet, the reflector, the reflection case, etc. be able to.
[0191]
  Furthermore, the planar illumination device according to claim 13 is a light source, an incident portion that guides light from the light source, and a position corresponding to the luminance distribution or light energy distribution of the light source.LightIt has an inclined surface corresponding to the light flux from the source.Discontinuous optical elements and optical elementsIt is applied to a density distribution that increases functionally in proportion to the distance from the light source.,lightLight emitted from the optical element to the front surface portion or the back surface portion facing the first optical deflection element or / and the optical element that is finer than the optical element between the rows of the optical elements and finer than the optical element A light guide plate provided with a second light deflection element that slightly refracts a part of the light guide plate, and a reflector that covers the light guide plate other than the incident portion and the exit surface and reflects the leaked light from the light guide plate again into the light guide plate Because it has, the position where the brightness and energy from the light source are always equalLightTotal reflection, refraction, and the like are performed by the inclined surface of the scientific element, and the same luminance and energy can be emitted to the emission surface side. Moreover, the product of the amount of light emitted at every position of the light guide plate and its solid angle is equal so that the density distribution of the optical element increases in proportion to the distance from the light source as the luminance and energy from the light source decrease. The emission angle from the emission surface and the optical element itself can be continuously changed by setting the angle of the inclined surface.
[0192]
  In addition, a multi-row with a highly directional white light source, etc.Light ofA part of the light beam traveling from the light source to the optical element can be diffused by the first light deflecting element. As a result, the continuity of the visible spectrum (rainbow) is lost (disturbed), the recognition of the visible spectrum (rainbow) is disturbed, and the occurrence of the visible spectrum (rainbow) on the exit surface is prevented without lowering the output brightness. it can.
[0193]
  In addition, a highly directional white light source etc. and multiple rowsLight ofSpectral generation of light that appears on the exit surface by the diffraction grating element by the optical element can diffuse a part of the light beam from the light source to the optical element by the first light deflecting element, and is connected to the incident part of the light guide plate The light incident on the light guide plate from the edge of the front and back surfaces is repeatedly totally reflected on the front and back surfaces.AccompanyingA part of bright and dark light beams having periodicity with different brightness and the like that reach the exit surface due to interference is a second light deflection element having a large diameter with respect to the height (so-called part of an arc having a large curvature radius). A light beam that reaches and exits to the outside from the second light deflection element can be emitted at a different exit angle that is finer than that of the flat surface portion. Accordingly, it is possible to prevent the occurrence of bright and dark light stripes or the like without causing a slight disturbance of bright and dark light having periodicity and reducing the emission luminance.
[0194]
  Furthermore, in the case of a concave optical element, the visible spectrum (rainbow) that appears by Newton prism spectroscopy when the part where the light guide plate and the concave optical element are connected has two mirror surfaces such as a prism shape, It is possible to prevent the light beam traveling to the element from being totally reflected by the first light deflecting element and proceeding to the optical element, thereby preventing the generation of the visible spectrum (rainbow).
[0195]
  Also, multiple columns with regularityLight ofEven if the light is emitted uniformly in the same direction by the scientific element itself, and the generation of a visible spectrum (rainbow) due to light spectroscopy appears on the exit surface, a part of the visible spectrum (rainbow) is slightly deflected to make the visible spectrum The regularity of the (rainbow) can be disturbed to prevent the generation of the visible spectrum (rainbow) and make the visible spectrum (rainbow) inconspicuous.
[0196]
  Further, the convex first light deflecting element and the second light deflecting element provided on the front surface portion and the back surface portion of the light guide plate, the diffusion sheet provided near the front surface portion and the back surface portion, and the lower portion of the back surface portion. It is possible to prevent the light guide plate from being adhered to a certain reflector or reflection case. As a result, it is possible to easily obtain the desired effect without impairing the original functions of the diffusion sheet, the reflector, the reflection case, etc., and to obtain outgoing light that is easy to see without directly observing the diffusion sheet, the reflector, the reflection case, etc. be able to.
[0197]
  Therefore, it is possible to prevent the generation of the visible spectrum (rainbow) due to the dispersion of light appearing on the exit surface without lowering the exit brightness, and the brightness of the exit light by direct light from the optical element or the like depending on the directivity and brightness of the light source. Designed with a wide range of freedom, such as emphasizing brightness, viewing angle, or uniformity, depending on the required purpose of the flat lighting device. And a flat illumination device may be possible.
[0198]
  Still further, in the flat illumination device according to claim 14, since the light source is a white light source having directivity or / and directivity distribution, the distance from the incident portion of the light guide plate is not equal to the light source plate. Directivity can be matched. Thereby, the light of a light source can be utilized efficiently.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a flat illumination device according to the present invention.
FIG. 2 is a schematic view of a light guide plate according to the present invention.
FIG. 3 is a schematic view of a light guide plate according to the present invention.
FIG. 4 is a schematic view of a light guide plate according to the present invention.
FIG. 5 is a schematic view of a light guide plate according to the present invention.
FIG. 6 is a schematic view of a light guide plate according to the present invention.
FIG. 7 is a schematic view of a light guide plate according to the present invention.
FIG. 8 is a schematic view of a light guide plate according to the present invention.
FIG. 9 is a schematic view of a light guide plate according to the present invention.
FIG. 10 is a schematic view of a light guide plate according to the present invention.
FIG. 11 is a schematic view of a light guide plate according to the present invention.
FIG. 12 is a schematic view of a light guide plate according to the present invention.
FIG. 13 is a schematic view of a light guide plate according to the present invention.
14 is a partially enlarged view of the light guide plate of FIG.
FIG. 15 is a schematic locus diagram of light rays of a light guide plate according to the present invention.
FIGS. 16A and 16B are schematic locus diagrams of light rays of a light guide plate according to the present invention. FIGS.
FIGS. 17A and 17B are schematic locus diagrams of light rays of a light guide plate according to the present invention. FIGS.
FIG. 18 is a schematic locus diagram of light rays of a light guide plate according to the present invention.
FIG. 19 is a schematic locus diagram of light rays of a light guide plate according to the present invention.
FIG. 20 is a schematic locus diagram of light rays of a light guide plate according to the present invention.
FIG. 21 is a schematic view of a light guide plate according to the present invention.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Plane illumination apparatus, 2 ... Light guide plate, 3, 4, 4b ... Light source, 5, 7 ... Incident part, 6, 6a, 6b ... End part, 8 ... Surface part, 9 ... Back surface part, 10 ... Reflection end surface part , 11 ... side face part, 14 ... reflector, 15 ... reflector, 16 ... terminal electrode, 20, 20 '... optical element, 21, 22 ... inclined surface, 21a, 21b ... interval, 30 ... light deflecting element, 40 ... light Refraction element, β ... incident angle, α ... refraction angle, γ ... critical angle, n ... refractive index, θ ... angle formed by the front and back surfaces and the inclined surface, L0, L1, L11, L12, L2, L21, L22, L30, L40, LL, L3, LL4, LL0, LL0 ′.

Claims (14)

In a light guide plate having an incident portion that guides light from a light source, a front surface portion that emits the light, and a rear surface portion that is located on the opposite side of the front surface portion, the front surface portion and / or the rear surface portion is the luminance of the light source. density function to increase distance in proportion from the light source to the optical element provided with an optical element continuous with an inclined surface corresponding to the light beam from the previous SL light source distribution or positions corresponding to the light energy distribution applied to the distribution, the optical element finer than a concave shape or / and the first light guide plate and providing a light deflector convex between the column and the previous column's rating optical element. In a light guide plate having an incident portion that guides light from a light source, a front surface portion that emits the light, and a rear surface portion that is located on the opposite side of the front surface portion, the front surface portion and / or the rear surface portion is the luminance of the light source. to functionally increases in proportion to the distance from the light source to the optical element provided with discontinuous optical elements having an inclined surface corresponding to the light beam from the previous SL source at a position corresponding to the distribution or light energy distribution subjected to density distribution, the optical element finer than a concave shape or / and the first light guide plate and providing a light deflector convex between the column and the previous column's rating optical element.   The first light deflection element is provided on the front surface portion and / or the back surface portion more randomly or closer to the incident portion, and has a height of 1 μm to 4 μm and a maximum width of 4 μm to 16 μm. 3. The light guide plate according to claim 1, wherein the light guide plate has a weight shape or a circular arc shape or a conical shape having a diameter in a range of 4 to 16 [mu] m. In a light guide plate having an incident portion that guides light from a light source, a front surface portion that emits the light, and a rear surface portion that is located on the opposite side of the front surface portion, the front surface portion and / or the rear surface portion is the luminance of the light source. density function to increase distance in proportion from the light source to the optical element provided with an optical element continuous with an inclined surface corresponding to the light beam from the previous SL light source distribution or positions corresponding to the light energy distribution applied to the distribution, the second light guide plate and providing a light deflector for fine refracting a portion of light emitted by the pre-Symbol optical element to the surface portion or the back portion facing the optical element. In a light guide plate having an incident portion that guides light from a light source, a front surface portion that emits the light, and a rear surface portion that is located on the opposite side of the front surface portion, the front surface portion and / or the rear surface portion is the luminance of the light source. to functionally increases in proportion to the distance from the light source to the optical element provided with discontinuous optical elements having an inclined surface corresponding to the light beam from the previous SL source at a position corresponding to the distribution or light energy distribution subjected to density distribution, the second light guide plate and providing a light deflector for fine refracting a portion of light emitted by the pre-Symbol optical element to the surface portion or the back portion facing the optical element.   The second light deflection element has an arc shape with a diameter in the range of 5 μm to 100 μm and a height in the range of 1/20 to 1/80 of the diameter, and is randomly or incident on the front surface portion or the back surface portion. The light guide plate according to claim 4, wherein the light guide plate is provided in a greater number as it is closer to the portion.   The light guide plate according to claim 1, wherein the optical element has a triangular shape, a trapezoidal shape, or an arc shape in cross section and is continuous or discontinuous.   The light guide plate according to any one of claims 1, 2, 4, and 5, wherein the height of the optical element increases or / and partially increases or decreases as the distance from the light source increases.   The angle between the inclined surface and the front surface portion and the back surface portion is in the range of π / 2-2 · critical angle to critical angle. Light guide plate.   The guide according to any one of claims 1, 2, 4, and 5, wherein an angle formed between the inclined surface and the front surface portion and the back surface portion approaches a critical angle in proportion to a distance from the light source. Light board.   The inclined surface is formed with an arc inside or outside centering on a central portion of the inclined surface, or with an arc partially inside and outside the inclined surface. The light guide plate according to any one of 2, 4, and 5. A light source, an incident portion for guiding light from the light source, provided with an optical element in a continuous to have a sloped surface corresponding to the light beam from the previous SL source at a position corresponding to the luminance distribution or light energy distribution of the light source wherein performing optical element at a distance proportional to functionally density distribution increasing from the light source, before Symbol fine concave / or convex than the optical element between the column and the row of optical elements A light guide plate provided with a first light deflection element or / and a second light deflection element that minutely refracts part of the light emitted by the optical element on a front surface portion or a back surface portion facing the optical element; A flat illumination device comprising: a reflector that covers the light guide plate other than the incident portion and the emission surface and reflects light leaked from the light guide plate again into the light guide plate. A light source, an incident portion for guiding light from the light source, providing an optical element that have a sloped surface corresponding to the light beam from the previous SL source at a position corresponding to the luminance distribution or light energy distribution of the light source discontinuously wherein performing optical element distance proportionally functionally density distribution increasing from the light source, fine concave and / or convex shape than the optical element between the column and the previous column's rating optical element with A light guide plate provided with a first light deflection element or / and a second light deflection element that minutely refracts part of the light emitted by the optical element on a front surface portion or a back surface portion facing the optical element; A flat illumination device comprising: a reflector that covers the light guide plate other than the incident portion and the light exit surface and reflects light leaked from the light guide plate again into the light guide plate.   14. The flat illumination device according to claim 12, wherein the light source is a white light source having directivity or / and directivity distribution.

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