JP2005026223A - Light guide plate for surface light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide plate for emitting light excellent in uniformity and appearance from a light emitting surface and restraining the generation of bright streaks. <P>SOLUTION: In the light guide plate of a surface light emitting device which has an emitting surface and a reflecting surface facing each other and in which a plurality of dots are formed on the reflecting surface, the dots are arranged at intersection points of at least a pair of of straight lines in longitudinal and lateral directions in an interstitial area so as to have continuous and arbitrary density distribution in approximately vertical and parallel directions against the incident end surface of an arbitrary plate, and such arbitrary density distribution is represented at intervals of the straight lines in longitudinal and lateral directions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light guide plate of a surface light emitting device for spreading light from a light source over the entire light emitting surface for output.

  2. Description of the Related Art In recent years, a surface light emitting device that emits light from a light emitting diode that is a point light source in a planar shape is used as a light source such as a liquid crystal backlight. In this surface light emitting device, light from one or more light emitting diodes is incident from one end surface of a light guide plate having opposing main surfaces, and the light is emitted from the entire one main surface of the light guide plate. Configured as follows. More specifically, the surface light emitting device includes a light guide plate having an outer frame made of a resin material or a metal material, a reflective surface and an output surface, a light emitting diode provided to face the incident end surface of the light guide plate, and a light guide plate. And a reflector provided on the reflective surface side of the light source, and emits light from the light emitting diode from the reflective surface of the light guide plate.

  In the surface light emitting device configured as described above, the light output from the light emitting diode decreases as it propagates through the light guide plate and decreases as it moves away from the light source. Therefore, a light diffusing dot pattern is formed on the reflective surface. We are trying to obtain uniform surface emission. This light diffusing dot pattern is formed to obtain uniform surface light emission. Such a light diffusing dot pattern is formed with a high density especially in a portion where light does not easily reach such as a corner on the light source side.

JP 11-119219 A

  However, since the light diffusing dot pattern formed in the portion where light does not easily reach in this way is randomly arranged in addition to the regular matrix-like arrangement, the adjacent dot interval becomes extremely large, Sometimes it gets smaller. The reflected light of the light in such a part has a directivity different from that of the other part, and there arises a problem that the light diffusing dots are visually recognized and the appearance of the surface emission is deteriorated.

  Accordingly, an object of the present invention is to provide a light guide plate that can emit light with a uniform and attractive appearance on the light emitting surface and can suppress the visual recognition of the light diffusing dots.

  In order to achieve the above object, the light guide plate of the first surface light emitting device according to the present invention has a light emitting surface and a reflective surface facing each other, and a plurality of dots are formed on the reflective surface. In the light guide plate, at least one set of vertical lengths is provided so that the dots have an arbitrary density distribution in the vertical direction and in the substantially parallel direction with respect to the incident end surface of the light guide plate in the interstitial region. It is arrange | positioned at the intersection of the straight line of a direction and a horizontal direction, It is characterized by the above-mentioned.

  With such a configuration, the dots can be arranged in accordance with different desired density changes for each grid area, so that a desired light amount can be obtained with high accuracy from the exit surface of the light guide plate.

  The light guide plate of the second surface light emitting device according to the present invention has an arbitrary density distribution continuous in a substantially vertical direction and a substantially parallel direction with respect to the incident end surface of the light guide plate in the lattice region. It is set to obtain uniform surface light emission from the light guide plate.

  With such a configuration, surface light emission with good uniformity can be obtained.

  Moreover, the light guide plate of the third surface light emitting device according to the present invention has an arbitrary density distribution that is continuous in a substantially vertical direction and a substantially parallel direction with respect to the incident end surface of the light guide plate in the lattice region. Is represented by an interval between the vertical and horizontal straight lines.

  By adopting such a configuration, the dots are smoothly arranged in the lattice-like regions, respectively, so that it is possible to obtain surface light with good appearance.

  The light guide plate of the fourth surface light emitting device according to the present invention is characterized in that the interval between dots adjacent in the vertical direction is different in the lattice region.

  By adopting such a configuration, smooth dot arrangement can be achieved even between grid-like regions adjacent in the vertical direction, so that appearance and uniformity can be further improved.

  The light guide plate of the fifth surface light emitting device according to the present invention is characterized in that the intervals between the dots adjacent in the horizontal direction are different in the lattice area.

  By adopting such a configuration, it is possible to achieve a smooth dot arrangement between grid-like regions adjacent in the horizontal direction, so that appearance and uniformity can be improved and generation of bright lines can be suppressed. .

  The light guide plate of the sixth surface light emitting device according to the present invention is characterized in that, in the lattice region, the interval between dots adjacent in the vertical direction and the horizontal direction differs depending on the distance and angle from the light source.

  By adopting such a configuration, surface light emission that can realize a smooth change in dot density in the vertical and horizontal directions according to the amount of light from the light source, and can extract a large amount of light with high controllability. Can be realized.

  The light guide plate of the seventh surface light emitting device according to the present invention is characterized in that the dots are also formed on the boundary of the lattice-like region.

  By setting it as such a structure, visual recognition of the boundary part of a grid | lattice area | region can be prevented, and appearance can be improved.

  The light guide plate of the eighth surface light emitting device according to the present invention is characterized in that the dots are arranged so as to form a vertical line and a horizontal line in the lattice area.

  With such a configuration, the distance between the dots can be maintained at a constant interval, so that abnormal light emission can be prevented. Moreover, it becomes easy to perform dot processing.

  The light guide plate of the ninth surface emitting device according to the present invention is such that the vertical line formed by the dots in the grid area is at least one grid area between a set of grid areas in the vertical direction. The dots are arranged so that the vertical lines formed by the dots in the above and the vertical lines formed by the dots in the other lattice-shaped region do not form one straight line.

  With such a configuration, generation of bright lines can be suppressed, so that surface emission with good uniformity and good appearance can be obtained.

  In the light guide plate of the tenth surface light emitting device according to the present invention, the vertical lines formed by the dots in the lattice region are formed by the dots in one lattice region in all lattice regions. The dots are arranged so that the vertical lines formed by the dots in the other grid area do not form one straight line.

  With such a configuration, generation of bright lines can be prevented, and thus surface emission with excellent uniformity and appearance can be obtained.

  According to the dot arrangement method as described above, the dot density for each grid can be adapted not only to the Y direction which is the optical axis direction but also to the dot density change in the X direction which is the light source arrangement direction. It is possible to arrange dots over the entire area. In addition, the conventional method corresponds to a change in dot density in one dimension only in the Y direction, and compared with a method formed by a method in which dots are randomly arranged between light sources or corners that are particularly dark, A smooth dot density change can be realized on a two-dimensional surface without the dots being extremely narrow or wide. In addition, since the dot arrangement pattern is different for each grid, a vertical line and a horizontal line do not form one straight line between adjacent grids, so that bright lines can be prevented. Furthermore, since the dot density changes smoothly in the X and Y directions beyond the grid boundaries, dots are also placed near the grid boundaries, making the grid boundaries inconspicuous and uniform. It becomes possible to improve the nature.

  Hereinafter, a light guide plate of a surface light emitting device according to an embodiment of the present invention will be described with reference to the drawings. The light guide plate according to the present embodiment is inputted from a light source by forming a large number of dots so as to satisfy a predetermined distribution on a reflection surface which is the other main surface opposite to an emission surface which is one main surface. The light guide plate of the surface light emitting device is configured so that the emitted light is uniformly emitted from the emission surface, and the predetermined distribution is realized by a dot pattern unique to the present application. That is, in the light guide plate of the present embodiment, the following light diffusion dots are formed from the incident end surface side where the light source is provided on the reflection surface. FIG. 12 is a schematic enlarged view of the light guide plate showing an example of the distribution of dots formed on the reflection surface of the light guide plate.

  The light diffusing dots are formed so as to have different densities in grids (lattice-like regions) partitioned in advance in a lattice shape on the reflection surface of the present embodiment. In the grid, each dot is arranged by forming a vertical line 11 in a substantially vertical direction and a horizontal line 12 in a substantially parallel direction with respect to the incident end face of the light guide plate. The dots form the vertical lines 11 and the horizontal lines 12 in this way. The density distribution in the grid is represented by the intervals of a plurality of vertical straight lines 1 and horizontal straight lines 2, and dots are arranged at the intersections thereof. This is because that. These straight line 1 in the vertical direction and straight line 2 in the horizontal direction are straight lines used on the software in the dot arrangement process, and are not visually recognized in the actual light guide plate shape. However, since dots are connected in rows and columns and arranged in a straight line, they are recognized as the vertical line 11 and the horizontal line 12, and are therefore shown separately.

In such a line, a strip region Ra _k (k = 1, 2, 3,..., N) in the X direction in which the grid is continuous in the horizontal direction (X direction), and a grid is continuous in the vertical direction (Y direction). A continuous density change is shown in the band-like region Rb _k (k = 1, 2, 3,..., N) in the Y direction. Therefore, the density change in each X direction and Y direction can be expressed in each grid, and at the same time, since dots may be arranged at the grid boundaries, the visibility of the grid boundaries may be eliminated. Therefore, the light guide plate of the surface light emitting device having a good appearance can be obtained.

  Further, in the vertical line 11 and the horizontal line 12 formed in the grid, the interval between adjacent dots is not uniform. Furthermore, the number and position of dots differ for each grid. Since the dot density change and the arrangement position are not constant in the grid as described above, the vertical lines 11 and the horizontal lines 12 by the dots in the grid intentionally form one continuous straight line between adjacent grids. Therefore, generation of bright lines can be suppressed.

Since these grids are set to be sufficiently small compared to the length of the light guide plate, depending on the size and density of the grid, such as dots in the grids represented by Ra ₃ and Rb ₃ in FIG. In some cases, there are no dots, and there are only one dot.

  In addition, since a constant dot pattern is not formed for each grid and a finer design can be performed, it is possible to provide a surface light emitting device with good brightness and good appearance, and grids adjacent in the optical axis direction. Since the probability that each vertical line forms one straight line is extremely low, bright lines can be further prevented.

  Hereinafter, an example of a dot array pattern setting method in the present embodiment will be described. In the embodiment of the present invention, the arrangement direction of the light emitting diodes in the light guide plate is the horizontal direction or the X direction, the optical axis direction of the light emitting diodes is the vertical direction or the Y direction, and the position on the light guide plate is the X coordinate (grid Number) and Y coordinate (grid number).

(Data input)
In the dot arrangement pattern setting method according to the embodiment of the present invention, first, values necessary for dot pattern setting are input. The data necessary at this time is the data on the size of the light guide plate, the size of the grid used for the calculation, the coordinates and the density, and the like. First, the dot size is determined in consideration of the size and shape of the light guide plate. Further, the size of the grid is determined in consideration of the size of the dots. For example, when the size of the light guide plate is 34 × 45 mm, if the dot size is φ60 μm and the grid size used for calculation is 1 × 1 mm, sufficient dot processing can be performed to obtain uniform surface light emission. In this embodiment, an area having a dot occupancy of 1 to 80%, or an area obtained by dividing at least one side of the light guide plate by 3 to 300 is defined as one grid. The specific length of one side of the grid is 0.5 to 30 mm.

  Further, the dot density at each position on the reflecting surface is set so that the luminance distribution on the light emitting surface is uniform in the surface. Here, the density at an arbitrary point 51 considered necessary for the calculation is determined. At this time, it is only necessary to arrange two or more data on the same Y coordinate (one row). Further, these arbitrary points 51 need not be limited to the center of the grid, and the numbers in each row and column are the same. It has not been decided. For example, as shown in FIG. 1, it is preferable to take a large number of points 51 indicated by dots with respect to the row of y1 that is a portion where the density change is large, but y3 is a portion where the density change at the center of the light guide plate is relatively small. Regarding the row, the number may be smaller than the number of points set by y1, and the points 51 at different X coordinates may be taken. The number and position of such points 51 can be arbitrarily set in order to obtain desired surface light emission.

  The dot density is set in accordance with the attenuation amount of light input from the light source, and the dot density increases as the light attenuation amount increases. In other words, the density distribution is changed from the incident end face side where the light source is provided to the other end face side, and at the same time, light is emitted from the corner (corner part) on the incident end face side, or between the light emitting diodes when multiple light emitting diodes are used. It is considered that incident light from the diode is difficult to reach and that the density is increased in a portion where the light flux density is low. In other words, the dot density decreases near the light source where the light attenuation is small, and increases at a distance from the light source where the light attenuation is large. Further, the density tends to increase when the angle with the optical axis of the light source is large, and the density tends to decrease when the angle with the optical axis of the light source is small.

(Creation of dot density map of light guide plate)
As described above, after setting the optimum dot density for each point in each arbitrarily set line such as y1 to y5 on the light guide plate as shown in FIG. An interpolation curve as shown in FIG. 2 is obtained by interpolating the graph of the X coordinate and the dot density in the Y coordinate. For example, spline interpolation may be used for interpolation, and spline interpolation is to cover dot density data in all coordinates (grids) by connecting arbitrary points with smooth curves. Thus, the respective interpolation curves obtained by performing interpolation using approximation are derived in all arbitrary rows, and the dot density D (dot density) in each grid in the X direction of y1 to y5 as shown in FIG. Distribution) can be calculated.

  Next, also in the y direction, by using the dot density change in the X direction obtained in FIG. 3 previously obtained, interpolation is performed for all the columns to obtain an interpolation curve as shown in FIG. It is possible to calculate the density change of dots in each grid in the Y direction. Since the dot density D of the center part of all the grids can be calculated at this time, it is possible to create a dot density map (FIG. 5) of the grid center part on the entire surface of the light guide plate. Specifically, as shown in FIG. 17, the dot density D at the center of the grid can be expressed in each grid. At this time, the dot density D at the center of the grid is considered as the average dot density in the grid. A graph having a smooth dot density change on a three-dimensional surface as shown in FIG. 6 can be obtained by a dot density map of the entire surface as shown in FIG.

(Dot placement)
Next, as shown in the schematic diagram of FIG. 7, a grid corresponding to the dot density is drawn in an area composed of rows and columns of each grid, and dots are arranged at the intersections. Such a lattice expresses the size of the dot density by making the straight line in the vertical direction and the straight line in the horizontal direction dense, or widening the interval. On the basis of the interpolation curve obtained from the three-dimensional graph of FIG. 6, in the X-direction strip region Ra _k (k = 1, 2, 3,..., N) composed of grid rows, A band-like region Rb _k (k = 1, 2, 3,..., N) in the Y direction composed of grid rows is obtained by drawing a straight line 2 in the horizontal direction. For the dot density change in the X direction, the interval of the straight line 1 in the vertical direction is changed, and for the dot density change in the Y direction, the interval of the horizontal line 2 is changed. Next, a method of determining the interstitial distance L by the vertical straight line 1 and the horizontal straight line 2 will be described.

First, in order to calculate the interval between the vertical lines in accordance with the change in the dot density of each portion in the X-direction band-like area Ra ₁ (first row of the grid), the density data of the X-direction band-like area Ra ₁ is shown in FIG. By taking out the interpolation curve (FIG. 8) from the two-dimensional graph, the dot density D can be calculated at an arbitrary X coordinate. Next, after drawing the first vertical straight line 1 to the portion of X = 0 corresponding to the left end of the light guide plate and calculating the dot density D at that point from the interpolation curve, the interstitial distance L corresponding to the dot density is calculated. obtain. Specifically, as shown in FIG. 9, first, the area of each lattice is obtained by the following equation (1), and each lattice interval (the length of one side of the lattice) is determined from the square root of the obtained area ((2 )formula).
Lattice plane lattice area (mm ² ) = (area of one dot (mm ² )) / (dot density D (%) / 100) (1)
Interstitial distance L (mm) = √ (lattice area) (2)

The second vertical line 1 is drawn by moving in the X direction by the lattice spacing L obtained by the above calculation. Similarly, the dot density D at the position (X coordinate) of the second vertical straight line 1 is based on the interpolation curve in the X-direction strip region Ra ₁ (grid first row) extracted from the above two-dimensional graph. Since it is obtained from the dot density data, the position of the third vertical line 1 is determined by converting the dot density D at the position of the second vertical line 1 to the interstitial distance L. Thus, it repeats from the left end which is one side edge part of a light-guide plate to the right end which is the other side edge part.

Through the above steps, a plurality of vertical straight lines 1 as shown in the schematic view of FIG. 10 in which the dot density change in the X-direction band-like region Ra ₁ (grid first row) is continuously changed are obtained. In addition, by performing the same operation in other rows (after the X-shaped band region Ra ₂ ), all the X-shaped band regions Ra _k (k = 1, 2, 3,..., N ), A straight line group in the vertical direction in which the dot density change is continuously changed can be obtained.

Next, the same process is performed in the Y-direction band-like region Rb _k (k = 1, 2, 3,..., N) in order from the Y-direction band-like region Rb ₁ (grid first row). First, the first horizontal straight line 2 is drawn on the light source side Y = 0 portion of the Y-direction band-like region Rb ₁ (grid first row) at the left end of the light guide plate, and the dot density D at that point is It is derived from the interpolation curve of the band-like region Rb _{1 in} the Y direction extracted from the three-dimensional graph of FIG. By applying the obtained dot density D to the above formulas (1) and (2), the distance to the second horizontal line 2 is determined. Subsequently, the dot density D at the Y coordinate of the second horizontal line 2 is calculated from the interpolation curve representing the dot density change of the band-like region Rb _{1 in} the Y direction, and the dot density D is converted into the interstitial distance L. Thus, the position where the third horizontal straight line 2 is arranged is determined. Such positioning of the straight line 2 in the horizontal direction is repeatedly performed from the Y = 0 portion which is the end portion on the light source side to the other end portion in the optical axis direction in the band-like region Rb ₁ in the Y direction of the light guide plate. By performing the above process over the entire area of the band-shaped area Rb _k in the Y direction (k = 1, 2, 3,..., N), the dot density change in the band-shaped area Rb _k in the Y direction is continuously performed by the vertical lines. 11 is obtained, and a lattice is drawn in which the vertical and horizontal straight lines intersect. In the obtained lattice, the change in dot density in the X direction and the change in dot density in the Y direction are represented by a straight line 1 in the vertical direction and a straight line 2 in the horizontal direction. Let the intersection of 2 be the dot placement position. By arranging the dots by such a method, it is possible to realize a dot arrangement corresponding to not only the dot density change in the Y direction but also the dot density change in the X direction. Since the dots are arranged on the vertical straight line 1 and the horizontal straight line 2, it is recognized that the vertical line 11 and the horizontal line 12 are formed by the respective dots.

  As shown in FIG. 10, the horizontal straight line 1 and the vertical straight line 2 have a dot density D at the position where each straight line (Nth line) is arranged, and the next straight line (N + 1th line). Is reflected in the distance L at which the line is arranged, and there is a deviation in the change in the distance between the arranged straight lines and the dot density, but the dot distance is sufficiently small, and such a deviation can be ignored. Since it is a range, there is no possibility of affecting the action of dots.

  According to the arrangement method according to the embodiment of the present invention, since dots are formed at the intersections of the vertical straight lines 1 and the horizontal straight lines 2 in each grid, compared to those in which dots are randomly arranged, The dot density changes discontinuously because the distance between dots does not become extremely wide or narrow, and abnormal light emission occurs due to multiple dots appearing very close and appearing as one large dot. Etc. can be prevented.

  Further, since the number of dots and the arrangement position are different for each grid, the vertical lines 11 in each grid do not intentionally form one continuous straight line between grids adjacent in the Y direction. Generation of bright lines can be suppressed. However, as an exception, when there is no change in dot density between adjacent grids, the vertical line 11 may form one continuous straight line between grids adjacent in the Y direction. It is almost impossible to form one continuous straight line over the other. However, if the problem of bright line generation occurs, it can be prevented by shifting the vertical line 11 and the horizontal line 12 by dots in the grid in the X direction and the Y direction.

(Dot position correction)
Since the dot arrangement method according to the embodiment of the present invention is discontinuous textured arrangement at the boundary between grids, dots may overlap each other or the interval may be too wide. Show. The dot position correction method according to the embodiment of the present invention is not limited to the following.

a) When dots overlap each other When dots overlap as shown in FIG. 12, for example, the inter-dot distance (distance between dot centers) is 1.1 times or less the dot diameter, and the inter-dot distance is 0.6. If it is equal to or less than double, dots overlapping two average coordinates are collectively arranged as shown in FIG. Further, when the inter-dot distance is not less than 0.6 times the dot diameter and not more than 1.1 times, the dots are moved away from each other as shown in FIG. The distance to be moved is set to one third of the space existing between the dots in the moving direction.

b) When the distance between the dots is wide As shown in FIG. 15, when the distance between the dots arranged at the ends at the grid boundary is wide, the distance between the four dots arranged at the ends and the diagonal ones. Calculate L1 and L2. Next, the dot density D at the boundary point of the grid is calculated from the dot density map, and the interstitial distance L is calculated from the dot density D using the above formulas (1) and (2). At this time, when both L1 and L2 are larger than L, specifically, when larger than 1.1 times L, one dot is added to the average coordinates of the four grids. However, the addition is not performed if the diameter of the four dots around the added dot is 1.3 times or less.

(Dot shape)
In the present invention, the dot may be a dot formed of a concave portion or a dot formed of a convex portion, and those having various shapes described below can be applied. Hereinafter, preferred dot shapes that can be used in the present invention will be described with reference to FIGS. Here, in FIGS. 18 to 23, (a) is a sectional view and (b) is a plan view. The present invention is not limited to the dot shape shown in FIGS. 18 to 23, and can be applied to other shapes. Hereinafter, the shape shown in each figure will be briefly described.

  FIG. 18 shows dots formed by relatively simple recesses that are recessed from the reflection reference surface Rf, and the dots of this shape are easy to manufacture. Further, FIG. 19 is a dot in which a peak raised from the reflection reference surface Rf is formed in a ring shape, and FIG. The dot has a higher light scattering effect than the dot formed of a simple recess in FIG.

  FIG. 21 shows dots formed by relatively simple convex portions raised from the reflection reference surface Rf, and the dots of this shape are easy to manufacture. Further, FIG. 22 is a dot whose center is raised in a dot recessed from the reflection reference surface Rf, and FIG. 22 is a dot whose periphery is recessed in the dot formed of the convex portion in FIG. The dots shown in FIGS. 22 and 23 have a higher light scattering effect than the dots formed by simple protrusions shown in FIG.

  19, 20, 22, and 23, each dot having a convex portion and a concave portion has a high light scattering ability. For example, when forming a concave portion by pressing a pointed pin against a resin plate By utilizing the fact that the periphery of the concave portion swells, it can be manufactured relatively easily, and high reproducibility can be secured by managing the pressing conditions. In addition, this method can be applied to a mold having a plurality of pins, and mass production is also possible.

  In the present invention, using the fact that the light scattering ability of the dots varies depending on the shape of the dots described above, in addition to the dot density and the dot arrangement described in the embodiment, the luminance in each part of the light emitting surface including the shape of each dot Can be adjusted. In this way, it is possible to adjust the luminance of the light emitting surface more delicately, which cannot be adjusted only by the dot density and the dot arrangement.

  Furthermore, in FIGS. 18 to 23, an example in which dots having a circular planar shape are used is shown. However, the present invention is not limited to this, and may be other shapes such as a quadrangle or a polygon. Furthermore, in the present invention, the shape of the dots may be different for each region depending on the amount of light scattering, so that the light emission luminance on the light emitting surface can be made more uniform.

It is a schematic plan view which shows the point which performs the density setting in the light-guide plate of embodiment which concerns on this invention. It is a graph which shows the interpolation curve of the arbitrary lines (y1) of the X direction in the light-guide plate of embodiment which concerns on this invention. It is a schematic plan view which shows that density distribution is covered to the whole area of arbitrary rows from the interpolation curve of the arbitrary rows of the X direction in the light-guide plate of embodiment which concerns on this invention. It is a graph which shows the interpolation curve of the arbitrary columns of the Y direction in the light-guide plate of embodiment which concerns on this invention. It is a typical top view which shows that the density distribution of the center part of the grid in the light-guide plate of embodiment which concerns on this invention is covered in the whole region. It is a graph which shows the three-dimensional dot density distribution of the X direction in the light guide plate of embodiment which concerns on this invention, and a Y direction. It is a schematic diagram showing the density change of the dot in the light-guide plate of embodiment which concerns on this invention. The 3-dimensional dot density distribution in the light guide plate of the embodiment according to the present invention obtained from the graph shown is a graph showing the density distribution of the band-like region Ra ₁ in the X direction. It is a schematic conceptual diagram showing a method for arranging a vertical direction line in the X-direction of the belt-like region Ra ₁ in the light guide plate of the embodiment according to the present invention. It is a schematic plan view showing an example of vertical linear arrangement in the X direction of the band-like region Ra ₁ in the light guide plate of the embodiment according to the present invention. It is a schematic plan view which shows one example of the dot arrangement | positioning in the light-guide plate of embodiment which concerns on this invention. It is a schematic diagram which shows the example of a correction | amendment of dot arrangement | positioning in the light-guide plate of embodiment which concerns on this invention. It is a schematic diagram which shows the example of a correction | amendment of dot arrangement | positioning in the light-guide plate of embodiment which concerns on this invention. It is a schematic diagram which shows the example of a correction | amendment of dot arrangement | positioning in the light-guide plate of embodiment which concerns on this invention. It is a schematic diagram which shows the example of a correction | amendment of dot arrangement | positioning in the light-guide plate of embodiment which concerns on this invention. It is a figure which shows the specific example of the density setting in the light-guide plate of embodiment which concerns on this invention. It is a figure which shows the specific example of the dot density map in the light-guide plate of embodiment which concerns on this invention. It is sectional drawing (a) and top view (b) which show the shape of the dot applicable to the light-guide plate of embodiment which concerns on this invention. It is sectional drawing (a) and top view (b) which show the shape of the dot applicable to the light-guide plate of embodiment which concerns on this invention. It is sectional drawing (a) and top view (b) which show the shape of the dot applicable to the light-guide plate of embodiment which concerns on this invention. It is sectional drawing (a) and top view (b) which show the shape of the dot applicable to the light-guide plate of embodiment which concerns on this invention. It is sectional drawing (a) and top view (b) which show the shape of the dot applicable to the light-guide plate of embodiment which concerns on this invention. It is sectional drawing (a) and top view (b) which show the shape of the dot applicable to the light-guide plate of embodiment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vertical straight line 2 ... Horizontal straight line 11 ... Vertical line 12 ... Horizontal line 21 ... Dot 31 ... Light guide plate 32 ... Light source 41 ... Grid (grid-like area | region) boundary line 51 ... The point which sets density

Claims (10)

In a light guide plate of a surface light emitting device having an emission surface and a reflection surface facing each other, and a plurality of dots formed on the reflection surface,
In the interstitial region, the dots have at least one set of longitudinal and lateral directions so as to have an arbitrary density distribution that is continuous in a substantially vertical direction and a substantially parallel direction with respect to the incident end face of the light guide plate. A light guide plate for a surface light emitting device, wherein the light guide plate is disposed at an intersection of straight lines. In the lattice region, an arbitrary density distribution that is continuous in a direction substantially perpendicular to and substantially parallel to the incident end face of the light guide plate is set to obtain uniform surface light emission from the light guide plate. The light guide plate of the surface light-emitting device according to claim 1. In the lattice area, an arbitrary density distribution which is continuous in a substantially vertical direction and a substantially parallel direction with respect to the incident end face of the light guide plate is represented by a distance between straight lines in the vertical direction and the horizontal direction. The light guide plate of the surface light-emitting device according to claim 1 or 2. 4. The surface light emitting device according to claim 1, wherein, in the lattice-like region, the interval between adjacent dots in the vertical direction is different. 5. The surface emitting device according to any one of claims 1 to 3, wherein in the lattice-like region, the interval between the dots adjacent in the horizontal direction is different. 4. The light guide plate of a surface light emitting device according to claim 1, wherein an interval between dots adjacent to each other in the vertical direction and the horizontal direction in the lattice area varies depending on a distance and an angle from the light source. The light guide plate of the surface light-emitting device according to claim 1, wherein the dots are also formed on a boundary of the lattice area. The light guide plate of the surface light emitting device according to claim 1, wherein the dots are arranged in a vertical line and a horizontal line in the lattice area. The vertical lines formed by the dots in the grid area are at least between a set of grid areas in the vertical direction, and the vertical lines formed by the dots in one grid area and the other grid pattern. 9. The light guide plate of a surface light emitting device according to claim 8, wherein the dots are arranged so that a vertical line formed by the dots in the region does not form one straight line. The vertical lines formed by the dots in the lattice area are formed by the dots in one lattice area and the dots in the other lattice area in all the lattice areas. 9. The light guide plate of a surface light emitting device according to claim 8, wherein the dots are arranged so that the vertical lines formed do not form one straight line.

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