JP2004273203A - Light guide and display using the same - Google Patents

Abstract

An object of the present invention is to reduce the thickness of a light guide main body, increase the use efficiency of light with respect to incident light, and efficiently and uniformly spread light in a plane.
In a planar light guide for guiding light in a planar manner, at least one incident coupler (2) for taking incident light into the interior of the light guide main body (1) is provided on a flat portion on the light guide main body (1). The incident coupler 2 is configured by a diffractive optical element having a function of converting incident light into light guided inside the light guide body while spreading light on a plane parallel to the plane portion of the light guide body.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a planar light guide for guiding light in a plane, and a display using the same, and more particularly to a light guide for a planar illumination light source, and an LCD for emitting light from the light guide. The present invention relates to a display body used as illumination light for a display element such as a panel.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, planar light guides that guide light in a planar manner have been used in many applications, including use as an optical member for a back light source of a display element such as an LCD panel.
[0003]
In particular, a light guide as an optical member for a back light source of a display element such as an LCD panel is typically formed of a transparent resin having a thickness of about 1 to several mm.
[0004]
In general, light is incident on the light guide from a direction perpendicular to the plane portion at the end face of the light guide.
[0005]
[Problems to be solved by the invention]
However, in such a conventional light guide, optical efficiency such as reduction of light use efficiency with respect to incident light and generation of undesired light components (for example, uneven brightness and components that cannot be used as illumination light, etc.) are generated. Problem.
[0006]
When the size of the light source is small and the number thereof is small, it is difficult to efficiently and uniformly spread the light in a plane.
[0007]
On the other hand, the thickness of the light guide itself must be increased in order not to reduce the light use efficiency of the incident light, so it is conceivable to reduce the thickness of the light guide itself. It is not possible at present.
[0008]
The thickness of the light guide itself is not limited to the problem that the product cannot be made thin, but also has problems in weight, manufacturing cost, and the like.
[0009]
An object of the present invention is to achieve a reduction in the thickness of a light guide body, increase the efficiency of use of light with respect to incident light, and efficiently and uniformly spread light in a planar manner. An object of the present invention is to provide a light guide and a display using the same.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the invention corresponding to claim 1, in a planar light guide for guiding light in a plane, an incident coupler for taking incident light into the inside of the light guide main body is provided. At least one light guide is disposed on a plane portion on the light body, and the incident coupler converts the incident light into light guided in the light guide body while spreading light on a plane parallel to the plane portion of the light guide body. It is constituted by a diffractive optical element having a function.
[0011]
Therefore, in the light guide according to the first aspect of the present invention, the size of the incident coupler is increased by arranging the incident coupler for taking the incident light into the inside of the light guide main body on a flat portion on the light guide main body. Can be determined without being limited by the thickness of the light guide body, and an incident coupler sized to obtain a sufficient efficiency of taking in incident light can be used.
Accordingly, light can be efficiently incident on the planar light guide main body, and the thickness of the light guide main body can be reduced.
In particular, since the diffractive optical element constituting the incident coupler may have a thin structure (typically about 0.1 to 10 μm) as compared with other optical elements, the light guide is easily handled as a smooth plate or film. be able to.
Further, since the structure is extremely simple and the constituent materials are small, it can be manufactured at low cost.
Further, optically, the function of the diffractive optical element allows light to be spread evenly, and in particular, even when the size of the light source is small and the number is small (one case), the light is uniformly guided. Can be lighted.
Furthermore, even if the positional relationship between the light source and the light guide main body is slightly deviated, the incidence efficiency of light on the light guide main body does not significantly change, and the alignment between the light source and the light guide main body is simplified. .
[0012]
According to a second aspect of the present invention, in the light guide according to the first aspect of the present invention, the incident light is introduced into the light guide body at an angle equal to or larger than the critical angle by the incident coupler. .
[0013]
Therefore, in the light guide according to the second aspect of the present invention, the incident coupler takes the incident light into the light guide main body at an angle equal to or greater than the critical angle, so that the two planes of the flat light guide main body are formed. In the portion, total reflection occurs, and the inside of the planar light guide body can be guided very efficiently.
[0014]
Furthermore, in the invention corresponding to claim 3, in the light guide according to the invention described in claim 1 or 2, light guided inside the light guide main body is emitted to the outside of the light guide main body. At least one emission coupler is arranged on the light guide body.
[0015]
Furthermore, in the invention according to claim 4, in the light guide according to the invention according to claim 3, the exit coupler is constituted by a diffractive optical element.
[0016]
Therefore, in the light guide according to the third and fourth aspects of the present invention, an emission coupler for emitting light guided inside the light guide main body to the outside of the light guide main body is provided on the light guide main body. , Light can be efficiently emitted from the inside of the planar light guide main body at the position where the emission coupler is arranged.
That is, light can be selectively emitted from an arbitrary position on a plane, and light is guided in other regions, so that light can be used extremely efficiently.
Further, the diffractive optical element constituting the exit coupler may have a thin structure (typically about 0.1 to 10 μm) as compared with other optical elements, so that the light guide can be handled as a plate or a film.
[0017]
On the other hand, according to a fifth aspect of the present invention, in the light guide of the third or fourth aspect of the present invention, the size of the exit coupler is reduced on the side closer to the entrance coupler, and the size of the exit coupler is reduced. Therefore, it is set to be large.
[0018]
Therefore, in the light guide of the invention corresponding to claim 5, the size of the exit coupler is reduced by making the size of the exit coupler smaller on the side closer to the entrance coupler and increasing as the distance from the entrance coupler increases. Accordingly, it is possible to control the rate at which light from the light being guided is converted into emission light without significantly changing the optical design of the emission coupler. Can be injected.
[0019]
According to a sixth aspect of the present invention, in the light guide according to any one of the first to fifth aspects of the present invention, at least one of the incident coupler and the exit coupler has a diffraction structure. The optical element is a surface relief type diffraction element.
[0020]
Therefore, in the light guide of the invention corresponding to claim 6, the diffractive optical element constituting at least one of the incident coupler and the exit coupler is a surface relief type diffractive element, for example, an embossing technique or the like. The light guide can be easily and inexpensively mass-produced by using.
In particular, when both the input coupler and the output coupler are surface relief type diffraction elements, a light guide having all functions can be formed by one molding. At this time, if the incidence coupler and the emission coupler are formed on the same surface, the production becomes easier.
[0021]
According to a seventh aspect of the present invention, in the light guide according to the first aspect of the present invention, at least one of the incident coupler and the exit coupler has a diffraction structure. The optical element is a kinoform or a blazed diffraction grating.
[0022]
Therefore, in the light guide of the invention corresponding to claim 7, the light guide is realized by using a kinoform or a blazed diffraction grating as the diffractive optical element constituting at least one of the input coupler and the output coupler. The light utilization efficiency can be made extremely high when light is incident on the body body and / or when light is emitted from the light guide body.
[0023]
Further, in the invention according to claim 8, in the light guide according to any one of claims 1 to 5, at least one of the incident coupler and the emission coupler is configured. The diffractive optical element is a volume type diffractive element.
[0024]
Therefore, in the light guide of the invention corresponding to claim 8, the light use efficiency is improved by making the diffractive optical element constituting at least one of the incident coupler and the exit coupler a volume type diffractive element. In addition to being able to be extremely high, it is possible to block noise light and control display colors by the incident angle dependence and wavelength selectivity of the volume diffraction element.
[0025]
On the other hand, according to a ninth aspect of the present invention, in the light guide according to any one of the first to eighth aspects, at least one of the incident coupler and the exit coupler is a transmission type coupler. It is designed to be a diffraction element.
[0026]
Therefore, in the light guide according to the ninth aspect of the present invention, at least one of the input coupler and the output coupler can be disposed close to each other by using a transmission diffraction element. Alignment errors are not easily affected, and simple assembly can be performed.
In addition, since there is no need to provide a reflective layer or the like, it can be manufactured with extremely few steps.
[0027]
According to a tenth aspect of the present invention, in the light guide according to any one of the first to eighth aspects, at least one of the incident coupler and the exit coupler is a reflection type coupler. It is designed to be a diffraction element.
[0028]
Therefore, in the light guide of the invention corresponding to claim 10, at least one of the input coupler and the output coupler is a reflection type diffractive element, so that it faces the light incident surface of the light guide main body. Since it is arranged on the surface where light is reflected, it becomes possible to provide a reflection layer or the like, light loss is extremely small, and high efficiency can be easily achieved.
Also, when a surface relief type diffraction element is used, the height of the structure can be made smaller than that of a transmission type diffraction element when the height of the structure with the optimum diffraction efficiency is set, and the fabrication is easy. It becomes.
Further, in the case of a volume diffractive element, the wavelength can be selectively guided using the wavelength selectivity.
[0029]
Further, in the invention according to claim 11, in the light guide according to any one of claims 3 to 5, the emission coupler is formed of a light scattering element having a fine uneven surface. I am trying to do it.
[0030]
Therefore, in the light guide of the invention corresponding to claim 11, the emission coupler can be easily manufactured by configuring the emission coupler with a light scattering element having a fine uneven structure on the surface, and uniform scattering can be achieved. Obtainable.
In particular, when the incident coupler is a surface relief type diffraction element, a light guide having functions of incidence and emission can be easily formed by duplication of the surface irregularities.
[0031]
On the other hand, according to a twelfth aspect of the present invention, in the light guide according to any one of the first to eleventh aspects, the incident coupler is provided on a surface facing the light incident surface of the light guide body. And a reflection layer is provided over substantially the entire flat surface of the light guide body on which the incident coupler is disposed.
[0032]
Therefore, in the light guide according to the twelfth aspect of the present invention, the incident coupler is a reflection type diffraction element disposed on the surface of the light guide main body opposite to the light incident surface, and the light guide on which the incident coupler is disposed. By providing the reflective layer over substantially the entire flat surface of the body, light loss at the incident coupler is minimized, and light is emitted from the light guide body only on the surface without the reflective layer. In addition, light loss of the entire light guide is extremely small, and a highly efficient light guide can be easily obtained.
[0033]
According to a thirteenth aspect of the present invention, in the light guide according to any one of the first to twelfth aspects, the light guide body is provided on a plane portion of the light guide body on which the incident coupler is disposed. A plurality of injection couplers are arranged.
[0034]
Therefore, in the light guide of the invention corresponding to claim 13, by forming a plurality of emission couplers on the plane portion of the light guide main body on which the incident coupler is disposed, the formation surface of the light guide main body is formed. Only one surface is required, and it can be easily manufactured.
In particular, when the input coupler and the output coupler are surface relief type diffraction elements, only one surface can be molded, and mass production can be performed extremely inexpensively and easily.
[0035]
According to a fourteenth aspect of the present invention, in the light guide according to any one of the first to thirteenth aspects, at least one of the incident coupler and the exit coupler is formed into a curved shape. Of the diffraction grating.
[0036]
Therefore, in the light guide of the invention corresponding to claim 14, at least one of the input coupler and the output coupler is constituted by a curved diffraction grating, so that when divergent light enters, parallel light The light is diffracted as light having different shapes (or light having different degrees of divergence). When parallel light is incident, the divergent light is diffracted.
Therefore, it is extremely suitable as an incident coupler for guiding light from a point light source or the like into the light guide main body, or as an exit coupler for appropriately expanding and emitting light in the light guide main body.
Further, the way of spreading can be easily controlled by the shape of the curve.
[0037]
On the other hand, according to a fifteenth aspect of the present invention, in the light guide according to any one of the first to fourteenth aspects, the main light guide direction in a plane parallel to the plane portion of the light guide body. In the direction substantially perpendicular to the direction, the incident light is made to enter the light guide main body from the incident coupler at an angle of not less than 60 degrees and not more than 180 degrees in a substantially uniform light intensity distribution.
[0038]
Therefore, in the light guide of the invention corresponding to claim 15, in the direction substantially orthogonal to the main light guide direction in a plane horizontal to the plane portion of the light guide main body, the light enters the light guide main body from the incident coupler. The incident light spreads at an angle of not less than 60 degrees and not more than 180 degrees in a substantially uniform light intensity distribution, so that the incident light is in a plane substantially perpendicular to the main light guide direction of the light guide body. The light can be spread evenly.
Further, by setting the angle of the incident light to preferably 90 degrees or more, the uniformity of the light to be guided is improved and the non-uniform region of the light around the incident coupler can be narrowed.
[0039]
According to a sixteenth aspect of the present invention, in the light guide according to any one of the first to fifteenth aspects, light is incident on a plane substantially perpendicular to a plane portion of the light guide body. The incident light is made to enter the light guide body as substantially parallel light from the coupler.
[0040]
Therefore, in the light guide of the invention corresponding to claim 16, the incident light enters the light guide main body from the incidence coupler into the light guide main body as a substantially parallel light in a plane substantially perpendicular to the plane portion of the light guide main body. By doing so, it becomes easy to control the emission light at the emission coupler, it is possible to suppress the generation of unnecessary light, and to obtain the emission light having a preferable light amount distribution in a plane with high efficiency.
[0041]
Further, in the invention according to claim 17, in the light guide according to any one of claims 1 to 16, the thickness of the light guide body is set to 0.5 mm or less. ing.
[0042]
Therefore, in the light guide of the invention corresponding to claim 17, by setting the thickness of the light guide main body to 0.5 mm or less, the light guide having a small thickness can be used while increasing the light use efficiency. Can be realized.
Further, it can be bent in the manufacturing process, can be manufactured easily, and an inexpensive product can be easily realized.
Furthermore, a flexible display can be configured by using the light guide of the present invention as a light source in combination with a display element such as a film LCD.
In particular, when the thickness of the light guide main body is 0.2 mm or less, it is easy to manufacture with a manufacturing apparatus having a winding mechanism, and the mass productivity is extremely high.
[0043]
Further, in the invention according to claim 18, in the light guide according to any one of claims 1 to 17, the light guide body side of the light source that generates incident light is flattened. The light guide body and the light source are integrated with each other through close contact or an adhesive material.
[0044]
Therefore, in the light guide of the invention corresponding to claim 18, the light guide main body side of the light source that generates the incident light is flattened, and the light guide main body and the light source are integrally joined through close contact or an adhesive material. By doing so, light can be stably and efficiently introduced into the light guide main body without causing misalignment.
Further, when light enters the light guide from the light source, loss due to reflection or the like can be eliminated.
[0045]
On the other hand, in the invention according to claim 19, a display element such as an LCD panel is disposed on the light emitting surface of the light guide according to any one of the above-described inventions.
[0046]
Therefore, in the display body of the invention corresponding to claim 19, a display element such as an LCD panel is arranged on the light exit surface of the light guide of the invention according to any one of claims 1 to 18. By doing so, it is possible to realize a bright and thin display body with high light use efficiency.
[0047]
According to a twentieth aspect of the present invention, in the display according to the nineteenth aspect, an emission coupler is disposed at a corresponding position on the light guide body for each pixel of a display element such as an LCD panel. I am trying to do it.
[0048]
Accordingly, in the display body according to the present invention, the emission coupler is disposed at a corresponding position on the light guide body for each pixel of a display element such as an LCD panel, so that a light source such as a black matrix is provided. Since light is not emitted from the light guide to the region where the light is blocked, the light use efficiency can be further improved.
[0049]
According to a twenty-first aspect of the present invention, in the display according to the nineteenth aspect, the light guide is provided for each of R, G, and B cells constituting one pixel of a display element such as an LCD panel. The injection coupler is arranged at a corresponding position on the body.
[0050]
Therefore, in the display body of the invention according to claim 21, each cell of each color of R, G, and B constituting one pixel of a display element such as an LCD panel emits light to a corresponding position on the light guide body. By arranging the coupler, since light is not emitted from the light guide to a region where light is blocked, such as a black matrix, a full-color display with even higher light use efficiency can be performed.
[0051]
In the invention according to claim 22, in the display body according to claim 20 or claim 21, the emission coupler has a function of condensing emission light near a display element position such as an LCD panel. Like that.
[0052]
Therefore, in the display body of the invention corresponding to claim 22, the emission coupler has a function of condensing the emission light near the position of the display element such as an LCD panel, so that the emission light is transmitted to the cell of the display element. Even if the display element and the light guide body are displaced within the cell size range, the light emitted from the light guide is Continue to enter the cell.
Therefore, the allowable amount of the alignment error when the display element and the light guide are combined can be increased, and a bright display can be easily and stably manufactured.
Further, the spread of light emitted from the cells of the display element can be controlled by the distance between the light-collecting point and the size of the emission coupler, and the distance between the display element and the light guide, so that the observer can observe the image brightly. The viewing zone can be arbitrarily formed.
[0053]
Further, in the invention according to claim 23, in the display body according to any one of claims 19 to 22, the emission coupler has a wavelength selectivity for emitting light of a specific wavelength. I have to.
[0054]
Therefore, in the display body according to the twenty-third aspect of the present invention, color display can be easily performed by making the emission coupler have wavelength selectivity for emitting light of a specific wavelength.
In particular, at the time of full-color display, members such as color filters are not required, and a very efficient and bright display can be obtained.
[0055]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the present invention, an incident coupler that takes incident light into the light guide main body is disposed on a flat portion on the light guide main body, and the incident coupler is placed on a plane parallel to the flat portion of the light guide main body. A fundamental feature is that the diffractive optical element has a function of converting light into light guided inside the light guide body while spreading light.
[0056]
Hereinafter, embodiments of the present invention based on the above-described concept will be described in detail with reference to the drawings.
[0057]
(First Embodiment)
FIG. 1 is a perspective view showing an overall configuration example of a light guide using the incident coupler according to the present embodiment.
[0058]
In FIG. 1, at least one incident coupler 2 (in this example, one incident light coupler 2) for taking incident light into the inside of the light guide main body 1 is provided on a flat surface of the flat light guide main body 1 for guiding light in a plane. And the incident coupler 2 is a diffractive optical element having a function of converting incident light into light that is guided inside the light guide main body while spreading light on a plane parallel to the plane portion of the light guide main body. It is composed.
[0059]
That is, light emitted from a point light source 3 such as an LED or a semiconductor laser is incident on an incident coupler 2 arranged on a plane portion of a planar light guide main body 1, and a diffractive optical element of the incident coupler 2 is formed. The diffractive function allows the light to enter the plate-shaped or film-shaped light guide body 1 while spreading in a direction substantially perpendicular to the main light guide direction.
[0060]
In the present embodiment, the thickness of the light guide body 1 is set to 0.5 mm or less.
[0061]
Next, in the light guide of the present embodiment configured as described above, the incident coupler 2 for taking the incident light into the inside of the light guide main body 1 is arranged on a plane portion on the light guide main body 1. By doing so, the size (area) of the incident coupler 2 can be determined without depending on the thickness of the light guide main body 1, and the incident light can be determined in consideration of how the light from the light source 3 spreads. Can be used to obtain a sufficient take-up efficiency.
[0062]
Thereby, light can be efficiently incident on the planar light guide main body 1 and the thickness of the light guide main body 1 can be reduced.
[0063]
In particular, since the diffractive optical element constituting the incident coupler 2 may have a thin structure (typically about 0.1 to 10 μm) as compared with other optical elements, the light guide may be formed in the same manner as a smooth plate or film. Can be easily handled.
[0064]
Further, such a light guide has a very simple structure and requires only a small amount of constituent materials, so that it can be manufactured at low cost.
[0065]
Furthermore, optically, the function of the diffractive optical element allows light to be spread evenly, and in particular, even when the size of the light source 3 for inputting light to the incident coupler 2 is small and the number is small (one light source). In this case, the light can be uniformly spread over a sufficiently wide range to guide the light.
[0066]
Furthermore, since the light guide can be made thin, it can be used as a light guide having high light use efficiency for many uses, including use as a surface light source such as a lighting member of an LCD display device.
[0067]
In particular, when the thickness of the light guide is 0.5 mm or less, a light guide having a small thickness can be realized while increasing the light use efficiency.
[0068]
On the other hand, it can be bent in the manufacturing process, can be easily manufactured, and an inexpensive product can be easily realized.
[0069]
Further, by using the light guide of the present embodiment as a light source and combining it with a display element such as a film LCD (it is also possible to bond together), a flexible display can be constituted.
[0070]
In particular, when the thickness of the light guide is 0.2 mm or less, it can be easily manufactured by a manufacturing apparatus having a winding mechanism, and the mass productivity is extremely high.
[0071]
FIG. 2 is a side view showing an example of the entire configuration of a light guide using the incident coupler according to the present embodiment. The same parts as those in FIG. Only the part will be described.
[0072]
In FIG. 2, incident light is introduced into the light guide body 1 at an angle equal to or greater than the critical angle by the incident coupler 2.
[0073]
That is, the diffracted light travels at an angle exceeding the critical angle with respect to the plane portion of the light guide main body 1 by the incident coupler 2, and the interface between the plane portion of the light guide main body 1 (the outside of the light guide main body 1 and the light guide body). At the boundary).
[0074]
Next, in the light guide of the present embodiment configured as described above, the incident coupler 2 takes the incident light into the light guide main body 1 at an angle equal to or larger than the critical angle. Light is totally reflected inside the light guide main body 1 in a cross section substantially orthogonal to the plane portion of the light guide main body 1.
[0075]
That is, the critical angle is determined from the refractive index of the material forming the light guide main body 1 and the refractive index of the medium outside the light guide main body 1.
[0076]
For example, if the refractive index of the former is 1.5 and the refractive index of the latter is 1.0, the critical angle is an angle of about 42 degrees. Light incident on one interface is totally reflected.
[0077]
Since the light guided by total reflection has very little loss, it is optimal as a light guide.
[0078]
In addition, as a method of distributing light in the light guide main body 1, a method of reflecting and guiding light many times and a function of the diffractive optical element of the incident coupler 2 make it possible to substantially distribute the light to the plane portion of the light guide main body 1. There is a method in which the angular distribution of the diffracted light is expanded in a cross section orthogonal to the light guide, and distributed in the light guide body 1 with a small number of reflections (typically 0 or 1).
[0079]
These can be appropriately selected according to the conditions such as the reflection efficiency of the surface of the light guide body 1 and the emission coupler described later.
[0080]
FIG. 3 is a plan view showing an overall configuration example of a light guide using the incident coupler according to the present embodiment. The same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted. Here, only the different parts will be described.
[0081]
In FIG. 3, even if the light source 3 and the incident coupler 2 are relatively small, and the number of the light sources 3 and the incident couplers 2 is small, the incident coupler 2 is Due to the function of the diffractive optical element that constitutes, the light is spread and diffracted in the range of the angle 、 in the plane, so that the light is sufficient in the width direction of the plane of the light guide without the need for an additional optical element. Thus, the area near the entrance coupler 2 where the light does not spread can be narrowed.
[0082]
Further, as shown in FIG. 4, the function of converting the light quantity distribution with respect to the angle at the time of incidence (FIG. 4A) to a more uniform diffracted light distribution (FIG. And the light can be spread very uniformly within a plane.
[0083]
As a specific example, when a curved diffraction grating pattern as shown in the plan view of FIG. 5 is used, an effect of expanding light is obtained, and by locally changing the curvature and the lattice spacing of the curve, Conversion of the light amount distribution can be realized, and a substantially uniform light amount distribution can be formed in the angle range of the angle ξ.
[0084]
Depending on the application, the light quantity distribution of the diffracted light does not need to be uniform with respect to the angle, and can be appropriately designed so as to have an optimum distribution in the light guide.
[0085]
Note that these diffraction grating patterns are formed by general diffraction optics based on the distribution of the amount of light and the angle of the incident light on the surface of the incident coupler 2 on the light guide main body 1 and the distribution of the amount of light and the angle of the light diffracted from the incident coupler 2. It can be determined by theory.
[0086]
Here, in the direction substantially perpendicular to the main light guide direction in a plane parallel to the plane portion of the light guide main body 1, the light enters the light guide main body 1 from the incident coupler 2 at an angle ξ = 60 degrees or more. When the light intensity is spread to a substantially uniform light intensity distribution, light can be easily spread uniformly in a plane.
[0087]
For example, when the width of the plane of the light guide body 1 in the direction substantially orthogonal to the main light guide direction is 30 mm, and the width of the incident coupler 2 is 5 mm, the light guide body is 46.7 mm away from the incident coupler 2 in the main light guide direction. From the position, light can be distributed over the entire width of the light guide body 1.
[0088]
Here, preferably, when the angle ９０ is equal to or more than 90 degrees, the uniformity is improved and the non-uniform region of the light around the incident coupler 2 can be narrowed.
[0089]
At this time, the light can be distributed over the entire width of the light guide main body 1 from a position 30 mm away under the same conditions as in the case described above, and the region where the light is uniformly distributed on the light guide main body 1 is reduced. Can be wider.
[0090]
Of course, the divergence angle か ら from the incident coupler 2 can be set to 180 ° or close to 180 °. In this case, light can be distributed over the entire width of the light guide from immediately adjacent to the incident coupler.
[0091]
On the other hand, when the angle ξ is set to a value close to 180 degrees, the light intensity in the main light guide direction is increased, and the light intensity is decreased as the angle from the main light guide direction is increased. Light can be uniformly distributed throughout.
[0092]
The effects of "spreading light to the light guide body 1" and "uniformly guiding light" can be obtained especially when the light guide is used as an illumination member by increasing the effective area in which the light guide can be used as an illumination light source. Effective area is reduced), and the effect of making the illumination light uniform is obtained.
[0093]
In particular, the former can minimize unnecessary area and volume as a light source, and is particularly suitable as a light source for a small LCD panel.
[0094]
Furthermore, in the light guide of the present embodiment, even if the positional relationship between the light source 3 and the light guide main body 1 (incident coupler 2) is slightly shifted, if the size is sufficiently smaller than the size of the incident coupler 2, the light guide 3 The efficiency of light incidence on the main body 1 does not significantly change, and alignment between the light source 3 and the light guide main body 1 is simple.
[0095]
While the basic configuration example of the present invention has been described above, other configuration examples will be described below.
[0096]
(Second embodiment)
FIG. 6 is a plan view showing an overall configuration example of a light guide using a plurality of incident couplers according to the present embodiment, and the same parts as those in FIGS. 1 to 3 and FIG. A description thereof is omitted, and only different portions will be described here.
[0097]
That is, in the light guide according to the present embodiment, as shown in FIG. 6, light is incident on one light guide main body 1 using a plurality of sets (two sets in this example) of the incident coupler 2 and the light source 3. I try to make it.
[0098]
Next, in the light guide of the present embodiment configured as described above, since the two sets of the incident coupler 2 and the light source 3 are used, the light distribution in the light guide main body 1 is further improved. It can be more uniform.
[0099]
In addition, light can be uniformly guided to a larger light guide. For example, when the width of the plane of the light guide main body 1 in a direction substantially orthogonal to the main light guide direction is 30 mm, and the size of the incident coupler 2 is 5 mm × 5 mm, the direction from one incident coupler 2 to the main light guide Light can be distributed over the entire width of the light guide body 1 from a position 47 mm away, but if there are two incident couplers 2, light can be distributed over the entire width of the light guide body 1 from a position 18.7 mm away. Light can be distributed.
[0100]
(Third embodiment)
FIG. 7 is a plan view showing an example of the entire configuration of a light guide using the entrance coupler and the exit coupler according to the present embodiment, and the same parts as those in FIGS. 1 to 3 and FIGS. The description is omitted by attaching the reference numerals, and only different portions are described here.
[0101]
That is, the light guide according to the present embodiment, as shown in FIG. 7, transmits light for guiding the inside of the light guide main body 1 to the outside of the light guide main body 1 on the above-described light guide main body 1. A plurality of injection couplers 4 for injection (at least one injection coupler may be provided) are provided.
[0102]
Further, the plurality of emission couplers 4 are constituted by diffractive optical elements.
[0103]
Next, in the light guide according to the present embodiment configured as described above, the emission coupler 4 that emits the light guided inside the light guide main body 1 to the outside of the light guide main body 1 is connected to the light guide. By arranging a plurality of light on the body main body 1, light can be efficiently emitted from the inside of the planar light guide body 1 at the position where the emission coupler 4 is arranged.
[0104]
That is, light can be selectively emitted from an arbitrary position on a plane, and light is guided in other regions, so that light can be used extremely efficiently.
[0105]
In this case, the size of the injection coupler 4 is reduced on the side closer to the incident coupler 2 and is increased as the distance from the incident coupler 2 increases, so that the size of the injection coupler 4 depends on the size of the injection coupler 4. Since the rate of conversion from the light in the light guide to the emission light can be controlled without largely changing the optical design of 4, the light can be uniformly emitted from the planar light guide body 1.
[0106]
This means that the rate at which the light in the light guide gradually decreases in the light guide direction due to the divergence angle or emission on the optical path can be easily realized by compensating for the size of the emission coupler 4. .
[0107]
On the other hand, as shown in the plan view of FIG. 8, in a plane substantially perpendicular to the plane portion of the light guide main body 1, the incident light enters the light guide main body 1 from the incident coupler 2 as substantially parallel light. By this, the control of the emitted light in the emission coupler 4 becomes easy, the generation of unnecessary light is suppressed, and the emitted light having a preferable light amount distribution in a plane can be obtained with high efficiency.
[0108]
That is, when not only the optical design of the emission coupler 4 is easy, but also uniform emission light is desired to be obtained from the light guide main body 1, the light enters the plurality of emission couplers 4 from within the light guide main body 1. Since the angle of light is almost constant, the optical design of the plurality of emission couplers 4 is only required once, and it is only necessary to arrange a plurality of the same emission couplers 4 at the time of fabrication. Can be.
[0109]
(Fourth embodiment)
The light guide according to the present embodiment is a diffractive optical element that forms at least one of the input coupler 2 and the output coupler 4 as shown in the side views of FIGS. Is a surface relief type diffraction element.
[0110]
Next, in the light guide of the present embodiment configured as described above, the diffractive optical element constituting at least one of the incident coupler 2 and the exit coupler 4 is a surface relief type diffractive element. Accordingly, the light guide can be easily and inexpensively mass-produced by using, for example, an embossing technique.
[0111]
In particular, when both the input coupler 2 and the output coupler 4 are surface relief type diffraction elements, a light guide having all functions can be formed by a single molding.
[0112]
(Fifth embodiment)
In the light guide according to the present embodiment, in the light guide described above, the diffractive optical element constituting at least one of the incident coupler 2 and the exit coupler 4 is a kinoform or a blazed diffraction grating. ing.
[0113]
Next, in the light guide of the present embodiment configured as described above, the diffractive optical element constituting at least one of the incident coupler 2 and the exit coupler 4 is replaced with a kinoform or a blazed diffraction grating. By doing so, the light utilization efficiency at the time of entering the light guide main body 1 and / or at the time of exit from the light guide main body 1 can be extremely increased.
[0114]
When a blazed diffraction grating is used, it is more preferable to use a curved grating pattern in order to efficiently realize the function of spreading light.
[0115]
(Sixth embodiment)
In the light guide according to the present embodiment, in the light guide described above, the diffractive optical element constituting at least one of the incident coupler 2 and the exit coupler 4 is a volume diffractive element.
[0116]
Next, in the light guide of the present embodiment configured as described above, the diffractive optical element forming at least one of the incident coupler 2 and the exit coupler 4 is configured to be a volume diffractive element. Accordingly, the light use efficiency can be made extremely high, and at the same time, the light that becomes noise can be cut off and the display color can be controlled by the incident angle dependence and the wavelength selectivity of the volume diffractive element.
[0117]
(Seventh embodiment)
The light guide according to the present embodiment is a diffractive optical element that forms at least one of the input coupler 2 and the output coupler 4 as shown in the side views of FIGS. Is a transmission type diffraction element.
[0118]
Next, in the light guide of the present embodiment configured as described above, the diffractive optical element forming at least one of the input coupler 2 and the output coupler 4 is configured to be a transmissive diffraction element. As a result, the light source 3, the incident coupler 2, and the light guide body 1 can be integrated with each other because they are arranged on the light incident surface of the light guide body 1. Assembly can be performed.
[0119]
In addition, since there is no need to provide a reflective layer or the like, it can be manufactured with extremely few steps and can be easily used.
[0120]
(Eighth embodiment)
The light guide according to the present embodiment is a diffractive optical element that forms at least one of the input coupler 2 and the output coupler 4 as shown in the side views of FIGS. Is a reflection type diffraction element.
[0121]
Next, in the light guide of the present embodiment configured as described above, the diffractive optical element constituting at least one of the incident coupler 2 and the exit coupler 4 is a reflection type diffractive element. As a result, since the light guide body 1 is arranged on the surface facing the light incident surface, a reflection layer or the like can be provided, light loss is extremely small, and high efficiency can be easily achieved. .
[0122]
In addition, when a surface relief type diffraction element is used, when the height of the structure is optimized for diffraction efficiency, the height of the structure can be significantly reduced as compared with the case of a transmission type diffraction element, and fabrication Becomes easier.
[0123]
Further, in the case of a volume diffractive element, the wavelength can be selectively guided using the wavelength selectivity.
[0124]
(Ninth embodiment)
In the light guide according to the present embodiment, in the above-described light guide, the emission coupler 4 is formed of a light scattering element having a fine uneven structure on the surface.
[0125]
Next, in the light guide of the present embodiment configured as described above, the emission coupler 4 is made of a light scattering element having a fine uneven structure on the surface, so that it can be easily manufactured. And uniform scattering can be obtained.
[0126]
In particular, when the incident coupler 2 is a surface relief type diffraction element, a light guide having the functions of incidence and emission can be easily formed by duplication of the surface irregularities.
[0127]
(Tenth embodiment)
In the light guide according to the present embodiment, in the light guide described above, the incident coupler 2 is a reflection type diffraction element arranged on a surface of the light guide main body 1 facing the light incident surface, and the incident coupler 2 is arranged. The light guide body 1 is provided with a reflective layer over substantially the entire flat surface portion.
[0128]
Next, in the light guide of the present embodiment configured as described above, the incident coupler 2 is a reflection type diffraction element arranged on the surface of the light guide main body 1 facing the light incident surface, and By providing the reflective layer over substantially the entire surface of the light guide body 1 on which the light guide 2 is disposed, the loss of light in the incident coupler 2 is minimized and the light from the light guide body 1 is reduced. Since the light is emitted only on the surface without the reflective layer, light loss of the entire light guide is extremely small, and a highly efficient light guide can be easily obtained.
[0129]
(Eleventh embodiment)
In the light guide according to the present embodiment, in the above-described light guide, a plurality of emission couplers 4 are arranged on a plane portion of the light guide main body 1 on which the incident coupler 2 is arranged.
[0130]
Next, in the light guide of the present embodiment configured as described above, a plurality of emission couplers 4 are arranged on the plane portion of the light guide main body 1 on which the incident coupler 2 is arranged. Thereby, the formation surface may be only one surface of the light guide main body 1 and can be easily manufactured.
[0131]
In particular, when the input coupler 2 and the output coupler 4 are surface relief type diffractive elements, they can be formed on one surface of a substrate such as a flat plate or a film, and are extremely inexpensive and easily provided with high precision. Mass production can be performed.
[0132]
(Twelfth embodiment)
In the light guide according to the present embodiment, in the above-described light guide, at least one of the input coupler 2 and the output coupler 4 is configured by a curved diffraction grating.
[0133]
Next, in the light guide of the present embodiment configured as described above, at least one of the input coupler 2 and the output coupler 4 is configured by a curved diffraction grating. When divergent light is incident, the light is diffracted as parallel light (or light having a different degree of divergence), and when parallel light is incident, the divergent light is diffracted.
[0134]
Therefore, it is extremely suitable as the incident coupler 2 for guiding the light from the light source 3 such as a point light source into the light guide main body 1 or as the emission coupler 4 for appropriately expanding and emitting the light inside the light guide main body 1. .
[0135]
Further, the way of spreading can be easily controlled by the shape of the curve.
[0136]
(Thirteenth embodiment)
The light guide according to the present embodiment is different from the above-described light guide in that the light guide body 1 side of the light source 3 for generating incident light is flattened as shown in the side view of FIG. The light source 3 is integrated with the light source 3 through close contact or an adhesive material.
[0137]
Next, in the light guide according to the present embodiment configured as described above, the light source 3 that generates the incident light has a flat light guide body 1 side, and the light guide body 1 and the light source 3 are further By integrating them through close contact or an adhesive material, light can be stably and efficiently introduced into the light guide main body 1 without misalignment.
[0138]
Further, when the light enters the light guide main body 1 from the light source 3, loss due to reflection or the like can be eliminated.
[0139]
Furthermore, a light guide in which such a light source 3 is integrated is extremely easy to handle.
[0140]
It is preferable to use materials having substantially the same refractive index as the light guide body 1, the light source 3, the adhesive, and the like for integration (in order to extremely reduce the reflectance at each interface).
[0141]
Further, since the thickness of the light guide body 1 can be reduced, a small light source such as an LED light source or a semiconductor laser is also used as the light source 3 so that the overall thickness of the flat light source can be reduced. It is possible to provide the light source 3 which is extremely small in volume.
[0142]
In particular, by employing the configuration shown in FIG. 12, the entire light source 3 can be made substantially flat.
[0143]
(14th embodiment)
FIG. 13 is a side view showing an example of the entire configuration of a display body in which a light guide according to the present embodiment and an LCD panel are combined, and the same parts as those in FIGS. 1 to 3 and FIGS. The description is omitted by attaching the reference numerals, and only different portions will be described here.
[0144]
That is, the light guide according to the present embodiment has a configuration in which the LCD panel 5 is arranged as a display element on the light exit surface of the light guide main body 1 as shown in FIG.
[0145]
Next, in the display of the present embodiment configured as described above, the LCD panel 5 as a display element is arranged on the light exit surface of the light guide main body 1, so that light can be used. A highly efficient, bright and thin display body can be realized.
[0146]
(Fifteenth embodiment)
In the display according to the present embodiment, in the display described above, the emission coupler 4 is arranged at a corresponding position on the light guide body 1 for each pixel of the LCD panel 5 as a display element.
[0147]
Next, in the display body of the present embodiment configured as described above, the emission coupler 4 is arranged at a corresponding position on the light guide body 1 for each pixel of the LCD panel 5 as a display element. With this configuration, since light is not emitted from the light guide to a region where light is blocked, such as a black matrix, the light use efficiency can be further improved.
[0148]
(Sixteenth embodiment)
In the display according to the present embodiment, in the above-described display, when the LCD panel 5 serving as a display element is a color LCD panel, each of the R, G, and B cells forming one pixel of the LCD panel 5 is provided. The emission coupler 4 is arranged at a corresponding position on the light guide body 1.
[0149]
Next, in the display of the present embodiment configured as described above, for each cell of each color of R, G, and B constituting one pixel of the LCD panel 5, the corresponding position on the light guide main body 1 is set. By arranging the emission coupler 4 in a region, light is not emitted from the light guide to a region where light is blocked, such as a black matrix, so that full-color display with further improved light use efficiency is performed. be able to.
[0150]
(Seventeenth embodiment)
In the display body according to the present embodiment, as shown in the side view of FIG. 14, the emission coupler 4 has a function of condensing emission light near the position of the LCD panel 5 as shown in the side view of FIG.
[0151]
Next, in the display body of the present embodiment configured as described above, the emission coupler 4 has a function of condensing the emitted light near the position of the LCD panel 5, so that the emitted light is Even if the LCD panel 5 and the light guide main body 1 are displaced within the size of the cell because the light is converged or narrowed to a state close to the light condensing in the cell of the panel 5, the light guide is Outgoing light continues to enter the cells of the LCD panel 5.
[0152]
Therefore, the allowable amount of the alignment error when the LCD panel 5 and the light guide are combined can be increased, and a bright display can be easily and stably manufactured.
[0153]
Further, the spread of light emitted from the cells of the LCD panel 5 can be controlled by the point of light collection, the size of the emission coupler 4, and the distance between the LCD panel 5 and the light guide, so that the observer can be brightened. The viewing zone to be observed can be arbitrarily formed.
[0154]
(Eighteenth Embodiment)
In the display according to the present embodiment, in the display described above, the emission coupler 4 has wavelength selectivity for emitting light of a specific wavelength.
[0155]
Next, in the display body of the present embodiment configured as described above, since the emission coupler 4 has a wavelength selectivity for emitting light of a specific wavelength, color display can be easily performed. Can be.
[0156]
In particular, at the time of full-color display, members such as color filters are not required, and a very efficient and bright display can be obtained.
[0157]
(Other embodiments)
It should be noted that the present invention is not limited to the above embodiments, and can be implemented in various modifications without departing from the spirit of the invention at the stage of implementation.
For example, in each of the above embodiments, the case where an LCD panel is used as a display element has been described. However, the present invention is not limited to this, and another display element may be used.
[0158]
In addition, the above embodiments may be implemented in appropriate combinations as much as possible. In such a case, the combined effects can be obtained.
[0159]
Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent features.
For example, even if some components are deleted from all the components shown in each of the above embodiments, at least one of the problems described in the column of the problem to be solved by the invention can be solved, and When (at least one of) the effects described in the effect column is obtained, a configuration from which this component is deleted can be extracted as an invention.
[0160]
【The invention's effect】
As described above, according to the light guide of the invention corresponding to claim 1, the incident light is introduced into the light guide main body, and the incident light is transmitted to the light guide in a plane parallel to the plane portion of the light guide main body. Since the incident coupler composed of the diffractive optical element having a function of converting the light into light to be guided inside the light guide main body while expanding is formed on a flat portion on the flat light guide main body, Light can be efficiently incident on the light guide main body, and the thickness of the light guide main body can be reduced.
Optically, the light can be uniformly spread by the function of the diffractive optical element. In particular, even when the size of the light source is small and the number thereof is small, the light can be uniformly guided.
[0161]
Further, according to the light guide of the invention corresponding to claim 2, since the incident light is introduced into the light guide main body at an angle equal to or larger than the critical angle by the incident coupler, the planar light guide is provided. It is possible to guide the light inside the main body extremely efficiently.
[0162]
Further, according to the light guide of the invention corresponding to claim 3 and claim 4, the emission coupler for emitting the light guided inside the light guide main body to the outside of the light guide main body is provided. Since a plurality of light guides are formed on the main body, light can be selectively and efficiently emitted from the inside of the planar light guide main body at the position where the emission coupler is arranged.
[0163]
On the other hand, according to the light guide of the invention corresponding to claim 5, the size of the exit coupler is small on the side close to the entrance coupler and increases as the distance from the entrance coupler increases. Therefore, it is possible to control the rate at which light is converted from light being guided to emitted light without largely changing the optical design of the emission coupler, so that light can be uniformly emitted from the planar light guide body. Becomes possible.
More specifically, by compensating the rate at which the light in the light guide gradually decreases in the light guide direction due to the divergence angle and emission by the size of the emission coupler, it can be easily realized. .
[0164]
Further, according to the light guide of the invention corresponding to claim 6, since the diffractive optical element constituting at least one of the incident coupler and the exit coupler is a surface relief type diffractive element, The light guide can be easily and inexpensively mass-produced by using the embossing technique or the like.
In particular, when the incident coupler and the exit coupler are both surface relief type diffraction elements, it is possible to form a light guide having all functions by a single molding.
[0165]
Further, according to the light guide of the invention corresponding to claim 7, the diffractive optical element constituting at least one of the incident coupler and the exit coupler is a kinoform or a blazed diffraction grating. In addition, it is possible to extremely increase the light use efficiency when light enters the light guide body or / and when light is emitted from the light guide body.
In particular, in the case of a kinoform, it can be flexibly applied to arbitrary light wavefront conversion, and in the case of a blazed diffraction grating, the optical function is simply designed by the grating interval and grating pattern. In addition, the fabrication is relatively easy, and it is possible to easily produce a high-precision optical element.
[0166]
Furthermore, according to the light guide of the invention corresponding to claim 8, since the diffractive optical element constituting at least one of the incident coupler and the exit coupler is a volume diffractive element, The light use efficiency can be made extremely high, and the incident angle dependency and wavelength selectivity of the volume diffractive element can block noise light and control the display color.
[0167]
On the other hand, according to the light guide of the invention corresponding to claim 9, at least one of the input coupler and the output coupler is configured as a transmission type diffraction element. Since the light source, the incident coupler, and the light guide main body are integrated on the incident surface, the alignment can be prevented from being shifted.
In addition, even when they are not integrated, they can be arranged close to each other, so that alignment errors are hardly affected, and simple assembly can be performed.
Further, since there is no need to provide a reflective layer or the like, the device can be manufactured with few steps.
[0168]
According to the light guide of the invention corresponding to claim 10, at least one of the incident coupler and the exit coupler is configured as a reflection type diffraction element. Since it is arranged on the surface opposite to the incident surface, a reflective layer or the like can be provided, light loss is extremely small, and high efficiency can be easily achieved.
In the case of a surface relief type diffractive element, the height of the structure can be made smaller than that of a transmissive type diffractive element, and the fabrication can be facilitated.
Further, in the case of a volume diffractive element, it is possible to selectively guide the wavelength by utilizing the wavelength selectivity.
[0169]
Furthermore, according to the light guide of the invention corresponding to claim 11, since the emission coupler is made of a light scattering element having a fine uneven structure on the surface, it can be easily manufactured, and can be manufactured uniformly. Scattering can be obtained.
In particular, when the incident coupler is a surface relief type diffraction element, it is possible to easily form a light guide having the functions of incidence and emission by duplicating the surface irregularities.
[0170]
On the other hand, according to the light guide of the invention corresponding to claim 12, the incident coupler is a reflection type diffraction element disposed on the surface of the light guide main body opposite to the light incident surface, and the incident coupler is disposed. Since the reflective layer is provided over almost the entire surface of the light guide body, light loss at the incident coupler is minimized, and light is emitted from the light guide body only on the surface without the reflective layer. Therefore, light loss in the entire light guide body is extremely small, and a highly efficient light guide can be easily obtained.
[0171]
Further, according to the light guide of the invention corresponding to claim 13, since a plurality of emission couplers are arranged on the plane portion of the light guide main body on which the incident coupler is arranged, the formation surface is a light guide. Only one surface of the body is required, and it can be easily manufactured.
In particular, when the input coupler and the output coupler are surface relief type diffraction elements, only one surface can be formed, and mass production can be performed extremely inexpensively and easily.
[0172]
Further, according to the light guide of the invention corresponding to claim 14, since at least one of the incident coupler and the exit coupler is constituted by a curved diffraction grating, divergent light is incident. Then, the light is diffracted as parallel light (or light having different degrees of divergence). When the parallel light enters, the divergent light is diffracted, so that light from a point light source or the like is introduced into the light guide body. It is suitable as an incident coupler for guiding or as an exit coupler for appropriately expanding and emitting light in the light guide body.
The shape of the curve makes it possible to easily control the spread.
[0173]
On the other hand, according to the light guide of the invention corresponding to claim 15, in the direction substantially orthogonal to the main light guide direction in a plane horizontal to the plane portion of the light guide main body, the light from the incident coupler to the inside of the light guide main body. Since the light is made to spread in a substantially uniform light intensity distribution at an angle of not less than 60 degrees and not more than 180 degrees, the light is within a plane in a direction substantially orthogonal to the main light guide direction of the light guide body. It is possible to spread light uniformly.
Further, by setting the angle of the incident light to preferably 90 degrees or more, the uniformity of the light to be guided is improved, and the non-uniform region of the light around the incident coupler can be narrowed.
[0174]
Further, according to the light guide of the invention corresponding to claim 16, in a plane substantially perpendicular to the plane portion of the light guide main body, the light is incident from the incident coupler into the light guide main body as substantially parallel light. Therefore, it is easy to control the emission light at the emission coupler, and it is possible to suppress the generation of unnecessary light and obtain the emission light having a preferable light amount distribution in a plane with high efficiency.
[0175]
Furthermore, according to the light guide of the invention corresponding to claim 17, since the thickness of the light guide body is set to 0.5 mm or less, the light guide is thin while the light use efficiency is high. An optical body can be realized.
In addition, it can be bent in the manufacturing process, can be easily manufactured, and an inexpensive product can be easily realized.
Furthermore, a flexible display can be formed by combining the light guide of the present invention as a light source with a display element such as a film LCD.
In particular, when the thickness of the light guide body is 0.2 mm or less, the light guide body can be easily manufactured with a manufacturing apparatus having a winding mechanism, and the mass productivity can be extremely high.
[0176]
Still further, according to the light guide of the invention corresponding to claim 18, the light guide main body side of the light source that generates the incident light is flattened, and the light guide main body and the light source are united through close contact or an adhesive material. Therefore, light can be stably and efficiently introduced into the light guide main body without any misalignment.
Further, it is possible to eliminate a loss due to reflection or the like when the light enters the light guide from the light source.
[0177]
On the other hand, according to the display body of the invention corresponding to claim 19, since a display element such as an LCD panel is arranged on the light emitting surface of the light guide, the light use efficiency is high, and the brightness is high. In addition, it is possible to realize a thin display body.
[0178]
According to the display body of the present invention, the emission coupler is arranged at a corresponding position on the light guide body for each pixel of a display element such as an LCD panel. Since light is not emitted from the light guide to a region where light is blocked, such as a matrix, light use efficiency can be further improved.
[0179]
Further, according to the display body of the invention corresponding to claim 21, each cell of each color of R, G, B constituting one pixel of a display element such as an LCD panel is located at a corresponding position on the light guide body. Since an emission coupler is arranged, light is not emitted from the light guide to areas where light is blocked, such as a black matrix, enabling full-color display with even higher light use efficiency. It becomes.
[0180]
Further, according to the display body of the invention corresponding to claim 22, since the emission coupler has a function of condensing the emitted light near the position of the display element such as the LCD panel, the emitted light is transmitted to the LCD panel or the like. Even if the display element such as an LCD panel and the light guide body are displaced within the size of the cell, the light is guided even if the display element is narrowed down to the condensed or near condensed state in the cell of the display element. The light emitted from the light body continues to enter the cells of the display element such as an LCD panel.
Thus, the allowable amount of alignment error when a display element such as an LCD panel and a light guide are combined can be increased, and a bright display can be easily manufactured.
Also, the spread of light emitted from the cells of the display element such as an LCD panel can be controlled by the distance between the light-condensing point and the size of the emission coupler, and the distance between the display element such as an LCD panel and the light guide. It is possible to arbitrarily form a viewing zone that can be observed brightly by a person.
[0181]
Furthermore, according to the display body of the invention corresponding to claim 23, since the emission coupler has a wavelength selectivity for emitting light of a specific wavelength, color display can be easily performed.
In particular, at the time of full-color display, members such as a color filter are not required, and a very efficient and bright display can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an overall configuration example of a light guide using an incident coupler according to a first embodiment of the present invention.
FIG. 2 is a side view showing an overall configuration example of the light guide using the incident coupler according to the first embodiment of the present invention.
FIG. 3 is a plan view showing an overall configuration example of a light guide using the incident coupler according to the first embodiment of the present invention.
FIG. 4 is a diagram showing light intensity distributions before and after an incident coupler in the light guide according to the first embodiment.
FIG. 5 is a plan view showing another configuration example of the light guide using the incident coupler according to the first embodiment of the present invention.
FIG. 6 is a plan view showing an overall configuration example of a light guide using a plurality of incident couplers and emission couplers according to a second embodiment of the present invention.
FIG. 7 is a plan view showing an overall configuration example of a light guide using an entrance coupler and an exit coupler according to a third embodiment of the present invention.
FIG. 8 is a plan view showing another configuration example of the light guide using the entrance coupler and the exit coupler according to the third embodiment of the present invention.
FIG. 9 is a side view showing an overall configuration example of a light guide using an entrance coupler and an exit coupler according to fourth to eighth embodiments of the present invention.
FIG. 10 is a side view showing an example of the overall configuration of a light guide using an entrance coupler and an exit coupler according to the fourth to eighth embodiments of the present invention.
FIG. 11 is a side view showing an overall configuration example of a light guide using an entrance coupler and an exit coupler according to fourth to eighth embodiments of the present invention.
FIG. 12 is a side view showing an overall configuration example of a light guide using an incident coupler and an exit coupler according to fourth to eighth embodiments of the present invention.
FIG. 13 is a side view showing an example of the entire configuration of a display unit in which a light guide and an LCD panel are combined according to a fourteenth embodiment of the present invention.
FIG. 14 is a side view showing an example of the overall configuration of a display unit in which a light guide according to a seventeenth embodiment of the present invention and an LCD panel are combined.
[Explanation of symbols]
1. Light guide body
2 ... Injection coupler
3. Light source
4: Injection coupler
5 LCD panel.

Claims (23)

In a planar light guide that guides light in a plane,
At least one incident coupler for taking incident light into the interior of the light guide main body is disposed on a flat portion on the light guide main body,
The incident coupler is constituted by a diffractive optical element having a function of converting incident light into light to be guided inside the light guide body while spreading light on a plane parallel to the plane portion of the light guide body. A light guide, characterized in that: The light guide according to claim 1, wherein
A light guide, wherein incident light is introduced into the light guide body at an angle equal to or greater than the critical angle by the incident coupler. In the light guide according to claim 1 or 2,
A light guide, wherein at least one emission coupler for emitting light for guiding light inside the light guide body to the outside of the light guide body is disposed on the light guide body. The light guide according to claim 3, wherein
A light guide, wherein the emission coupler comprises a diffractive optical element. In the light guide according to claim 3 or 4,
A light guide, wherein the size of the exit coupler is reduced on the side close to the incident coupler, and increases as the distance from the incident coupler increases. The light guide according to any one of claims 1 to 5,
A light guide, wherein a diffractive optical element constituting at least one of the incident coupler and the exit coupler is a surface relief type diffractive element. In the light guide according to any one of claims 1 to 6,
A light guide, wherein a diffractive optical element constituting at least one of the incident coupler and the exit coupler is a kinoform or a blazed diffraction grating. The light guide according to any one of claims 1 to 5,
A light guide, wherein a diffractive optical element constituting at least one of the incident coupler and the exit coupler is a volume diffractive element. The light guide according to any one of claims 1 to 8,
A light guide, wherein at least one of the incident coupler and the exit coupler is a transmission diffraction element. The light guide according to any one of claims 1 to 8,
A light guide, wherein at least one of the incident coupler and the exit coupler is a reflection type diffraction element. The light guide according to any one of claims 3 to 5,
A light guide, wherein the emission coupler is constituted by a light scattering element having a fine uneven structure on the surface. The light guide according to any one of claims 1 to 11,
The incident coupler, a reflection type diffraction element disposed on a surface facing the light incident surface of the light guide body,
A light guide, comprising a reflection layer over substantially the entire surface of a plane portion of the light guide body on which the incident coupler is disposed. The light guide according to any one of claims 1 to 12,
A light guide, wherein a plurality of the emission couplers are arranged on a plane portion of the light guide body on which the incident coupler is arranged. The light guide according to any one of claims 1 to 13,
A light guide, wherein at least one of the input coupler and the output coupler is constituted by a curved diffraction grating. The light guide according to any one of claims 1 to 14,
In a direction substantially orthogonal to the main light guide direction in a plane parallel to the plane portion of the light guide body, incident light from the incident coupler into the light guide body is substantially at an angle of 60 degrees or more and 180 degrees or less. A light guide, wherein the light guide is made to spread and enter into a uniform light intensity distribution. The light guide according to any one of claims 1 to 15,
A light guide, wherein incident light is incident on the light guide body from the incident coupler as substantially parallel light in a plane substantially perpendicular to a plane portion of the light guide body. The light guide according to any one of claims 1 to 16,
A light guide, wherein the thickness of the light guide body is 0.5 mm or less. The light guide according to any one of claims 1 to 17,
Flatten the light guide body side of the light source that generates the incident light,
The light guide, wherein the light guide body and the light source are integrated with each other through close contact or an adhesive material. A display body comprising a light guide according to any one of claims 1 to 18, wherein a display element such as an LCD panel is disposed on a light exit surface of the light guide. 20. The display according to claim 19,
A display body, wherein the emission coupler is arranged at a corresponding position on the light guide body for each pixel of a display element such as an LCD panel. 20. The display according to claim 19,
A display body characterized in that the emission coupler is arranged at a corresponding position on the light guide body for each cell of each color of R, G, and B constituting one pixel of a display element such as an LCD panel. . In the display according to claim 20 or 21,
A display body, wherein the emission coupler has a function of condensing emission light near a position of a display element such as an LCD panel. The display according to any one of claims 19 to 22, wherein
A display body, wherein the emission coupler has a wavelength selectivity for emitting light of a specific wavelength.

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