JP7065441B2 - Light guide panel - Google Patents

Description

The present invention relates to a light guide panel using an LED light source.

A light guide panel using an LED light source is used in a surface lighting fixture that is thin and emphasizes design.

FIG. 12 is a diagram illustrating a configuration of a conventional light guide panel and a structure of a conical prism (see Patent Document 1). FIG. 12A is a configuration diagram of a conventional light guide panel. Reference numeral 10 is a light guide plate, which is a plate-shaped panel having 6 faces. Reference numeral 20 is a prism, which is formed by arranging a plurality of prisms one by one on a predetermined one surface of the light guide plate 10. Reference numeral 30 is an LED element, and a plurality of the LED elements are aligned and arranged so as to face another one surface different from the predetermined one surface on which the prism is formed in the light guide plate 10, and the inside of the light guide plate 10 is arranged from the other one surface. Irradiate the light. The light emitted from the LED element 30 to the inside of the light guide panel 10 is reflected by the prism 20 and emitted as reflected light in the direction opposite to the predetermined one surface on which the prism 20 of the light guide plate 10 is formed. ..

FIG. 12B is a diagram illustrating the structure of the prism 20. The prism 20 is a conical prism, and has a circular plane as a bottom surface, and a curved surface is formed from the end side of the bottom surface toward the apex.

FIG. 12C is a configuration diagram of another conventional light guide panel. Reference numeral 50 is a prism constituting the light guide plate 40.

FIG. 12D is a diagram illustrating the structure of the prism 50. The prism 50 is an extruded prism, and is formed by extruding the light guide plate 40 from a predetermined surface of the light guide plate 40 toward the inside of the light guide plate 40.

Japanese Patent Application Laid-Open No. 2003-255140

However, in the case of a light guide panel in which a plurality of conical prisms are arranged one by one on a predetermined one surface of the light guide plate 10, milling processing and laser dot processing make the cone relatively easy and low cost. Although it is possible to process a shaped prism, strong reflected light is generated around the conical prism, and the amount of light is small between adjacent conical prisms, so that the light emitted from the entire light guide plate 10 is periodic. There will be strength and weakness. That is, the light distribution controllability is lowered.

Further, in the case of an extruded prism, since the shape does not change in the extruded direction of the extruded prism, light is not scattered in the cross section thereof, and uneven brightness is likely to occur.

Further, regarding workability, it is necessary to use a time-consuming processing method such as shaper processing.

The present invention relates to a light guide panel in which a prism group formed of a plurality of conical prisms having excellent light distribution controllability, luminance unevenness, and processability is formed.

The light guide panel according to the present invention includes a light guide plate having a plurality of surfaces and capable of transmitting light, and a light source that irradiates light from the first surface of the light guide plate surfaces to the inside of the light guide plate. On the second surface, which is different from the first surface of the light guide plate, prisms formed by curved surfaces whose diameter gradually decreases from the surface of the second surface toward the inside of the light guide plate are adjacent to each other. It is characterized in that a plurality of prism groups formed side by side are formed by being in contact with or overlapping a part of other prisms adjacent to each other, and further, a plurality of prism groups are formed on the second surface.

By configuring the light guide panel according to the present invention as described above, the prism group as a reflector that reflects the light emitted from the light source has a continuous curved surface, so that the reflected light is diffusely reflected on the curved surface. The degree of doing becomes stronger. In addition, the diffusely reflected reflected light overlaps with each other, and the intensity of the light seen side by side in the vertical and horizontal directions of the light guide panel is less likely to occur, and uneven brightness is less likely to occur.

In addition, the light diffusely reflected by the continuous curved surface of the prism group overlaps to increase the intensity of the reflected light, and by forming a plurality of the prism groups aligned, the intensity of the entire emission surface of the reflected light is further increased, so that the light distribution is performed. Increased controllability.

In addition, since the prism group can be easily processed by a well-known conventional method, it has an effect of being excellent in processability.

It is a figure explaining the light guide panel which concerns on Embodiment 1 of this invention. It is a figure explaining the light guide panel which concerns on Embodiment 2 and Embodiment 3 of this invention. It is a figure explaining the light guide panel which concerns on Embodiment 4 of this invention. It is a figure explaining the light guide panel which concerns on Embodiment 5 of this invention. It is a figure explaining the light guide panel which concerns on Embodiment 6 of this invention. It is a figure which measured the light distribution diagram and the maximum luminous intensity of the light guide panel which concerns on Embodiment 6 of this invention. It is a figure explaining the light guide panel which concerns on Embodiment 7 of this invention. It is a figure which measured the luminance unevenness reduction property and the light distribution controllability of the light guide panel which concerns on Embodiment 7 of this invention. It is a figure explaining the light guide panel which concerns on Embodiment 8 of this invention. It is a figure explaining the light guide panel which concerns on Embodiment 8 of this invention. It is a figure explaining the light guide panel which concerns on Embodiment 9 of this invention. It is a figure explaining the structure of the conventional light guide panel and the structure of a conical prism.

(Embodiment 1)
(Structure of light guide panel)
Hereinafter, the light guide panel according to the first embodiment of the present invention will be described. FIG. 1 is a diagram illustrating a light guide panel according to the first embodiment of the present invention. FIG. 1A is a configuration diagram of a light guide panel, and 100 is a light guide plate. The light guide plate 100 has a plurality of surfaces, and LED elements 120 are arranged in the vicinity of the side surface (first surface) 110, which is one surface thereof, with respect to the first surface 110. A plurality of prism groups 140 are formed inside the light guide plate 100. The light guide panel of the present invention is composed of such a light guide plate 100 and an LED element 120.

A plurality of LED elements 120 are aligned and arranged in parallel with the first surface 110, and the inside of the light guide plate 100 is irradiated with light from the first surface 110. The light emitted from the LED element 120 to the inside of the light guide plate 100 is reflected by the prism group 140, and the lower surface opposite to the second surface 130, which is the upper surface of the light guide plate 100 on which the prism group 140 is formed (shown). It is emitted as reflected light from (1) to the outside.

The LED as a light source is not limited to the LED element 120 as described above, but has various configurations such that an LED element is provided at one end of a light guide tube and the light guide tube is provided along the first surface 110 of the light guide plate 100. Light source is applicable.

(Prism structure)
FIG. 1B is a perspective view showing a prism formed on the second surface of the light guide panel, and is a diagram illustrating the structure of the prism. In FIG. 1B, 150 is a prism, which is formed from the surface of the second surface 130, which is the upper surface of the light guide panel 100, toward the inside of the light guide plate 100. The prism 150 has a bottom surface 180 closed by an end side 170 of a circle centered on 160 along the second surface 130 of the light guide plate 100, and a vertex formed inside the light guide plate 100 from the end side 170. It is a conical shape in which a curved surface 200 whose diameter gradually decreases toward 190 is formed. The curved surface 200 is inclined toward the apex 190 at an angle θ formed by the diameter (dotted line) of the bottom surface 180. That is, when the radius in the case of a circle centered on the bottom surface 180 is indicated by a dotted line, the radius (diameter) gradually decreases from the bottom surface 180 toward the apex 190.

Here, in the entire volume of the present application, the shape of the bottom surface 180 may be a perfect circle, or may be an ellipse or a shape consisting of an arbitrary curve.

(Structure of prism group)
FIG. 1 (c) is a perspective view showing a group of prisms formed on a light guide panel. Reference numeral 140 is a group of prisms formed on the light guide plate 100, and the prism 150 described with reference to FIG. 1B is in contact with another prism 150 adjacent to each other or overlaps with a part of another prism 150 adjacent to each other. , Is formed side by side.

As described with reference to FIG. 1A, by forming the prism group 140, the light emitted from the LED element 120 is emitted from the first surface 110 of the light guide plate 100 to the inside of the light guide plate 100, and FIG. 1 (a) As shown by the solid line arrow or the dotted line arrow in c), it becomes specular reflected light and diffuse reflected light and is emitted to the outside of the light guide plate 100.

By configuring the light guide panel in this way, the prism group 140 as a reflector that reflects the light emitted from the LED element 120 has a continuous curved surface 200 of the prism 150, so that the reflected light is reflected on the curved surface 200. The degree of diffuse reflection increases. In addition, the diffusely reflected reflected light overlaps with each other, and the intensity of the light seen side by side in the vertical and horizontal directions of the light guide plate 100 is less likely to occur, and uneven brightness is less likely to occur. Further, by adjusting the distance between the prisms 150, the light distribution control becomes easy and the light distribution controllability is enhanced.

In all the embodiments of the present application, after the prism 150 is actually formed on the light guide plate 100, the bottom surface 180 of the prism 150 formed on the second surface 130 of the light guide plate 100 is not necessarily a perfect circle. Not limited to this, the end side 170 or the apex 190 of the prism 150 may not be clearly visible. Therefore, the prism group 140, the prism 150, the center 160, the end side 170, the bottom surface 180, the apex 190, and the curved surface 200 may be described as being virtually present at the position.

In addition, this embodiment may be applied mutatis mutandis to all other embodiments.

(Embodiment 2, Embodiment 3)
FIG. 2 is a diagram illustrating a light guide panel according to a second embodiment and a third embodiment of the present invention. FIG. 2A is a top view of the prism group 140. FIG. 2B is a perspective view of the prism 150.

As the second embodiment, as shown in FIG. 2A, the sizes or shapes of the prisms 150 may be different from each other, and the prisms 150 having the same size and shape and the prisms 150 having the same size or shape may be different from each other. Different prisms 150 may be mixed. As the third embodiment, the prisms 150 constituting the prism group 140 may be all formed in the same size and shape throughout the entire application.

The prism 150 can be formed in the shape of a cone, in which case the bottom surface 180 of the cone, the apex 190, the radius to the center 160 and the edge 170 of the bottom surface 180, and the center 160 and the apex 190 of the bottom surface 180. The shape or size of the prism 150 can be adjusted by adjusting these parameters at any time, where h is the connecting height and θ is the angle formed by the diagonal side z of the cone and the bottom surface 180.

Further, as another shape of the prism 150, the shape as shown in FIG. 2C may be used. In the prism 150 shown in FIG. 2 (c), the slope extending from the end side 170 of the bottom surface 180 to the apex 190 is a mortar-shaped curved surface, and the diameter extending horizontally from the center 160 to the end side 170 of the bottom surface 180 and the diameter thereof. When the angle formed by the minute side at the intersection of the diameter and the oblique side is θ, the angle θ gradually decreases from the bottom surface 180 toward the apex 190. That is, in FIG. 2C, there is a relationship of θ ₁ > θ ₂ > θ ₃ .

By configuring the prism 150 in this way, the light distribution controllability can be controlled to the optimum state, and the uneven brightness can be reduced.

In addition, this embodiment may be applied mutatis mutandis to all other embodiments.

(Embodiment 4)
FIG. 3 is a view illustrating the light guide panel according to the fourth embodiment of the present invention, and FIG. 3 (a) is a top view of the light guide plate 100 as viewed from the second surface 130 which is the upper surface side.

In FIG. 3A, the prism group 140 is composed of a plurality of prisms 150, and the bottom surface 180 of the prism 150 formed on the second surface 130 of the light guide plate 100 is formed in a circle by the end sides 170. The centers 160 of the bottom surface 180 of each prism 150 are arranged side by side on a straight line A of one dotted line. By configuring the prism group 140 in this way, the shape of the center of the prism 150 in the extrusion direction does not change, so that the light distribution controllability of the prism group 140 can be improved.

FIG. 3B is a perspective view of the prism group 140 described in FIG. 3A as viewed from diagonally above, and as described in FIG. 2C, each prism constituting the prism group 140 is formed. In the 150, a slope extending from the end side 170 of the bottom surface 180 to the apex 190 is formed by a mortar-shaped curved surface.

In FIG. 3B, three prisms 150 adjacent to each other are formed by overlapping a part thereof, and the part P in which a part of the prism 150A at the left end and a part of the prism 150B in the middle overlap each other is , Conducting. Further, the portion Q in which the part of the prism 150B at the right end and the part of the prism 150C at the right end overlap each other with respect to the part of the prism 150B in the middle is also conducting.

Further, the tangent line R formed by overlapping the prisms 150A and 150B and the tangent line Q formed by overlapping the prisms 150B and 150C may be sharply sharpened or smooth, respectively. It may be formed of a curved surface.

This aspect is the same when each prism 150 constituting the prism group 140 has a conical shape as described with reference to FIG. 2 (b).

As a result, the light emitted from the LED element 120 of FIG. 1A hits the plurality of wavy curved surfaces of the prism group 140 and is scattered, and the difference in the intensity of the reflected light depending on the reflected location becomes small. Luminance unevenness is reduced as compared with the case of the prism of No. 1, and the reflected light is collected and the amount of light is larger than that of the case of a single prism, so that the light distribution controllability is improved.

It should be noted that this embodiment may be applied mutatis mutandis to all other embodiments.

(Embodiment 5)
FIG. 4 is a view illustrating the light guide panel according to the fifth embodiment of the present invention, and is a top view of the light guide plate 100 as viewed from the second surface 130 on the upper surface side.

The prism group 140 is composed of a plurality of prisms 150, and the bottom surface 180 of the prism 150 formed on the second surface 130 of the light guide plate 100 is formed in a circle by the end sides 170, and the center 160 of each prism 150 is formed. Are arranged side by side on the curve B of one dotted line. By configuring the prism group 140 in this way, the prism group 140 can be configured three-dimensionally, and the light distribution controllability can be further improved as compared with the case where the prisms 150 are arranged on a straight line.

It should be noted that this embodiment may be applied mutatis mutandis to all other embodiments.

(Embodiment 6)
Next, FIG. 5 is a diagram illustrating a light guide panel according to the sixth embodiment of the present invention. FIG. 5 is a top view of the prism group 140 formed on the light guide plate 100 as viewed from the second surface 130 on the upper surface side. In FIG. 5, the shape of the bottom surface 180 formed on the second surface 130 of the light guide plate 100 of the plurality of prisms 150 constituting the prism group 140 is circular, and the end of the prism 150A at one end (left end) of the prism group 140 is formed. The maximum length gamma (γ) from the side 170A through the center 160 of the plurality of prisms 150 adjacent to each other to the end side 170B of the prism 150B at the other end (right end) of the prism group 140 is the prism group 140. It is larger than twice the diameter delta (δ) of the constituent prisms 150. That is, it shows that it has a relationship of γ> 2 × δ.

When this relationship is satisfied, the prism group 140 has higher light distribution controllability than a single prism 150, and can exhibit the original ability when the prism is a prism group.

FIG. 6 is a light distribution diagram and a diagram of measuring the maximum luminous intensity of the light guide panel according to the sixth embodiment of the present invention.

FIG. 6A is a light distribution diagram when γ = δ, and the data of the cross section A and the cross section B are close to each other, which is almost the same as the light distribution diagram when one conical prism is used. The maximum luminous intensity at this time was 181 cd.

FIG. 6B is a light distribution diagram when γ = 10 × δ, and the difference between the measured values of the A cross section and the B cross section becomes clearer than in the case of FIG. 6A, and the maximum at this time. The luminous intensity was also 270 cd, which was higher than that in the case of FIG. 6 (a).

FIG. 6C is a diagram showing the relationship between γ / δ and the maximum luminous intensity. The horizontal axis of FIG. 6 (c) is γ / δ, and the vertical axis is the maximum luminous intensity when γ = 10 × δ is 1, and it is shown that a sufficient maximum luminous intensity is reached at γ / δ = 2. rice field.

It should be noted that this embodiment may be applied mutatis mutandis to all other embodiments.

(Embodiment 7)
Next, FIG. 7 is a diagram illustrating a light guide panel according to the seventh embodiment of the present invention. FIG. 7 focuses on the prisms 150C and the prisms 150D that are adjacent to each other among the plurality of prisms 150 constituting the prism group 140, and the prism group 140 formed on the light guide plate 100 is viewed from the second surface 130 on the upper surface side. It is a top view.

In the seventh embodiment shown in FIG. 7, the shapes of the bottom surfaces 180C and 180D of the plurality of prisms 150C and 150D constituting the prism group 140 are circular, and the diameters of the bottom surfaces 180C and 180D are L. At this time, the distance K between the centers 160C and 160D of the bottom surfaces 180C and 180D is larger than 1/4 of the diameter L and smaller than 1/2 of the diameter L. That is, the relationship of (1/4 × L) <K <(1/2 × L) is satisfied.

If the distance K between the plurality of prisms 150 adjacent to each other becomes too large, the shape change of the prisms 150 in the extrusion direction (direction from the bottom surface 180 to the apex 190) becomes too large, and the light distribution controllability becomes low. On the other hand, if the interval K becomes too small, the performance of reducing the luminance unevenness decreases. That is, when the relationship of (1/4 × L) <K <(1/2 × L) is satisfied, both the performance of reducing luminance unevenness and the light distribution controllability can be achieved at the highest level.

FIG. 8 is a diagram in which the brightness unevenness reduction property and the light distribution controllability of the light guide panel according to the seventh embodiment of the present invention are measured.

FIG. 8A is a diagram showing the relationship between K / L and the maximum luminous intensity, where the horizontal axis is K / L and the vertical axis is the maximum luminous intensity when γ = 10 × δ is 1. As can be seen from FIG. 8A, if the distance K between the prisms 150 becomes too large, the shape change in the extrusion direction of the prism 150 becomes too large, and the orientation controllability becomes low. Therefore, the maximum luminous intensity rapidly decreases at K / L = 0.625, which indicates that K <(1/2 × L) is suitable.

FIG. 8B is a diagram showing the relationship between K / L and uniformity, where the horizontal axis is K / L and the vertical axis is the uniformity at a line 30 mm from the light entrance end (first surface). .. As can be seen from FIG. 8B, when the prism spacing K becomes too small, the luminance unevenness reducing property decreases, and when K / L = 0.25, the luminance unevenness becomes easy to feel 0.5. From this, it was shown that (1/4 × L) <K is suitable.

That is, from the actually measured values of FIGS. 8 (a) and 8 (b), when the relationship of (1/4 × L) <K <(1/2 × L) is satisfied, the performance and arrangement for reducing the luminance unevenness are arranged. It was shown that optical controllability can be achieved at the highest level.

It should be noted that this embodiment may be applied mutatis mutandis to all other embodiments.

(Embodiment 8)
Next, FIG. 9 is a diagram illustrating a light guide panel according to the eighth embodiment of the present invention. In FIG. 9, the dotted line E is a line parallel to the first surface 110 of the light guide plate 100, a line parallel to the arrangement direction of a plurality of LED elements 120 provided side by side, or as indicated by a white arrow. A line perpendicular to the optical axis direction of the light radiated from the LED element 120 to the inside of the light guide plate 100 through the first surface 110, and the dotted line F is a line perpendicular to the first surface 110 of the light guide plate 100, or a plurality of lines. It is a line perpendicular to the arrangement direction of the LED elements 120 provided side by side, or a line in the optical axis direction of light radiated from the LED element 120 to the inside of the light guide plate 100 through the first surface 110.

When the prism group 140 is formed of a plurality of prisms 150 arranged in a straight line, the center 160A of the bottom surface 180A of the prism 150A and the center 160B of the bottom surface 180B of the prism 150B are connected at both ends of the prism group 140. The dotted line C is inclined at an angle α with respect to the above-mentioned dotted line E. Alternatively, it can be said that the dotted line C connecting the prisms 150A and the prisms 150B at both ends of the prism group 140 is inclined at an angle (π / 2-α) with respect to the above-mentioned dotted line F. In other words, it can be said that the dotted line C connecting the prisms 150A and the prisms 150B at both ends of the prism group 140 is neither parallel nor vertical to either the dotted line E or the dotted line F.

With such a configuration, the angle α can be appropriately adjusted to form the prism group 140, the light distribution control can be facilitated, and the luminance unevenness can be reduced.

Next, FIG. 10 is a diagram illustrating a light guide panel according to the eighth embodiment of the present invention. FIG. 9 described above is an example in which the prism group 140 is formed by a plurality of prisms 150 arranged on a straight line, whereas in FIG. 10, a plurality of prism groups 140 are arranged on a curve. It is an example of the case where it is formed by the prism 150 of.

In FIG. 10, the definitions of the dotted line E and the dotted line F are the same as those in FIG. At this time, the dotted line C connecting the center 160C of the bottom surface 180C of the prism 150C and the center 160D of the bottom surface 180D of the prism 150D at both ends of the prism group 140 is inclined at an angle β with respect to the above-mentioned dotted line E. There is. Alternatively, it can be said that the dotted line C connecting the prisms 150C at both ends of the prism group 140 and the prism 150D is inclined at an angle of (π / 2-β) with respect to the above-mentioned dotted line F. In other words, it can be said that the dotted line C connecting the prisms 150C and the prism 150D at both ends of the prism group 140 is neither parallel nor vertical to either the dotted line E or the dotted line F.

With such a configuration, the angle β can be appropriately adjusted to form the prism group 140, the light distribution control can be facilitated, and the luminance unevenness can be reduced.

It should be noted that this embodiment may be applied mutatis mutandis to all other embodiments.

(Embodiment 9)
Next, FIG. 11 is a diagram illustrating the light guide panel according to the ninth embodiment of the present invention, and is a schematic view of the light guide panel 100 as viewed from above. In the ninth embodiment shown in FIG. 11, as shown in FIG. 11A, the first surface 110 of the light guide plate 100 is an uneven surface or a wavefront as a kind of uneven surface, and a plurality of prism groups 140 are formed. The line connecting the centers 160 of the prisms 150 is perpendicular to the optical axis of the light emitted from the LED element 120 facing the first surface 110 to the light guide plate 100. Alternatively, it is parallel to the dotted line E shown in FIG. 9 or FIG.

FIG. 11B is a schematic view of the light guide panel 100 as viewed from above. As shown in FIG. 11B, when the first surface 110 of the light guide plate 100 is a flat plate, the light indicated by the white arrow from the LED element 120 is emitted from the first surface 110 of the light guide plate 100 to the inside of the light guide plate 100. When incident on, light is incident on the area inside the two arrows, but light is not incident on the area indicated by the mesh line outside the two arrows according to Snell's law.

FIG. 11C is a schematic view of the light guide panel 100 as viewed from above. In the ninth embodiment, as shown in FIG. 11C, it is proposed that the first surface 110 of the light guide plate 100 is an uneven jagged surface. 11 (d) is a perspective view of the first surface 110 of FIG. 11 (c) as viewed from diagonally above. By forming the first surface 110 in this way, as shown in FIG. 11 (e), the light emitted from the LED element 120 reaches in the light guide plate 100 as compared with the case described in FIG. 11 (b). The range shown by the mesh that cannot be done is greatly reduced.

At this time, the arrangement direction of the prism group 140 shown in FIG. 11A is parallel to the arrangement direction of the LED elements 120 or the dotted line E shown in FIG. 9 or FIG. Explaining this with reference to FIGS. 9 and 10 described above, the angles α and β of the prism group 140 are 0 in FIGS. 9 and 10. That is, in FIGS. 9 and 10, the lines connecting the centers 160 of the bottom surfaces 180 of the prisms 150 at both ends of the prism group 140 are parallel to the first surface 110 of the light guide plate 100, or a plurality of lines are provided side by side. It is parallel to the arrangement direction of the LED elements 120. In other words, it is perpendicular to the optical axis direction of the light emitted from the LED element 120 through the first surface 110 to the inside of the light guide plate 100.

As described above, the invention in which the arrangement direction of the prism group 140 is parallel to the arrangement direction of the LED elements 120 and the invention in which the shape of the first surface 110 on which the light from the LED element 120 in the light guide plate 100 is incident is an uneven surface. By combining the above, wide-angle light distribution control can be performed in the direction perpendicular to the optical axis direction of the light incident on the light guide plate 100 from the LED element 120.

As another example, as shown in FIG. 11 (f), the shape of the first surface 110 of the light guide plate 100 may be a wavefront. FIG. 11 (g) is a perspective view when the shape of the first surface 110 of the light guide plate 100 is a wavefront.

In this case as well, it is possible to smoothly control the wide-angle light distribution as in the case described with reference to FIG. 11 (c).

It should be noted that this embodiment may be applied mutatis mutandis to all other embodiments.

100 light guide plate, 110 first surface, 120 LED element, 130 second surface, 140 prism group, 150 prism, 160 center, 170 end edge, 180 bottom surface, 190 vertices, 200 curved surface.

Claims (10)

A light guide plate that has multiple surfaces and can transmit light,
A light source for irradiating the inside of the light guide plate with light from the first surface of the light guide plate is provided.
On the second surface of the light guide plate, which is different from the first surface, prisms formed by curved surfaces whose diameters gradually decrease from the surface of the second surface toward the inside of the light guide plate are mutually arranged. A group of prisms formed side by side is formed by overlapping with a part of other adjacent prisms.
Further, a plurality of the prism groups are formed on the second surface.
The shape of each of the prisms constituting the prism group on the surface is a circle.
The distance between the centers of the circles of the plurality of prisms adjacent to each other constituting the prism group is larger than 1/4 of the diameter of the circles of the prisms, and the diameter of the circles of the prisms is 0. It is smaller than 625 and
A light guide panel, characterized in that , in at least one group of prisms, the centers of the circles are aligned on only one curve having substantially the same radius of curvature . A light guide plate that has multiple surfaces and can transmit light,
A light source for irradiating the inside of the light guide plate with light from the first surface of the light guide plate is provided.
On the second surface of the light guide plate, which is different from the first surface, prisms formed by curved surfaces whose diameters gradually decrease from the surface of the second surface toward the inside of the light guide plate are mutually arranged. A group of prisms formed side by side is formed by overlapping with a part of other adjacent prisms.
Further, a plurality of the prism groups are formed on the second surface.
The shape of each of the prisms constituting the prism group on the surface is a circle.
The distance between the centers of the circles of the plurality of prisms adjacent to each other constituting the prism group is larger than 1/4 of the diameter of the circles of the prisms, and the diameter of the circles of the prisms is 0. It is smaller than 625 and
Of the plurality of prisms constituting the prism group, a line connecting the centers of the circles of the prisms at both ends is the light of light emitted from the light source facing the first surface to the light guide plate. A light guide panel, characterized in that it is not perpendicular to or parallel to an axis . A light guide plate that has multiple surfaces and can transmit light,
A light source for irradiating the inside of the light guide plate with light from the first surface of the light guide plate is provided.
On the second surface of the light guide plate, which is different from the first surface, prisms formed by curved surfaces whose diameters gradually decrease from the surface of the second surface toward the inside of the light guide plate are mutually arranged. A group of prisms formed side by side is formed by overlapping with a part of other adjacent prisms.
Further, a plurality of the prism groups are formed on the second surface.
The shape of each of the prisms constituting the prism group on the surface is a circle.
The distance between the centers of the circles of the plurality of prisms adjacent to each other constituting the prism group is larger than 1/4 of the diameter of the circles of the prisms, and the diameter of the circles of the prisms is 0. It is smaller than 625 and
In the prism group, the centers of the circles are aligned on one straight line.
A light guide panel characterized in that the diameter of the circle located at the center of a straight line is the maximum, and the diameter of the circle decreases as the distance from the center increases . The light guide panel according to claim 1 or 2 , wherein the prism group includes a plurality of the prisms having different shapes from each other. The light guide panel according to claim 1 or 2 , wherein the plurality of prisms constituting the prism group all have the same shape. The light guide panel according to any one of claims 1 , 2, 4 or 5 , wherein in the prism group , the centers of the circles are aligned on one straight line. From the end on the surface of the prism at one end of the prism group, through the center of the circle of a plurality of prisms adjacent to each other, to the end on the surface of the prism at the other end of the prism group. The present invention is described in any one of claims 1 to 6 , wherein the maximum length of the prism group is larger than twice the diameter of the surface of the second surface of the prism constituting the prism group. Light guide panel. The first surface of the light guide plate is provided with irregularities.
Of the plurality of prisms constituting the prism group, a line connecting the centers of the circles of the prisms at both ends is the light of light emitted from the light source facing the first surface to the light guide plate. The light guide panel according to claim 1 or 3 , characterized in that it is perpendicular to an axis. The slope extending from the edge of the bottom to the apex is a mortar-shaped curved surface, and the angle between the diameter extending horizontally from the center of the bottom to the edge and the minute side at the intersection of the diameter and the edge is θ. The light guide according to any one of claims 1 to 8, wherein the light guide includes a prism group in which a prism having a prism whose angle θ gradually decreases from the bottom surface to the apex is included. panel. The distance between the centers of the circles of the plurality of prisms adjacent to each other constituting the prism group is larger than the diameter of the circle of the prism of 0.375, and the diameter of the circle of the prism is 0. The light guide panel according to any one of claims 1 to 9 , wherein the light guide panel is smaller than 5.

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