KR100919445B1 - Light guide panel - Google Patents

Abstract

PURPOSE: A light guide plate for capable of improving the luminance of light and the efficiency of the light are provided to improve the efficiency of the light and increase the light by forming a center of the plate. CONSTITUTION: A light guide plate(100) includes a plate(110) and a plurality of reflecting pattern(120) on the rear side of the plate. The reflection pattern proceeds the light in which it is inlaid through each light-in surface in the frontal surface of the plate. The first patterns each reflection pattern is in a line with the cross direction of the plate. A second pattern is in a line in lengthwise of the plate in which they are shorter than the length of the first patterns.

Description

Light guide plate {LIGHT GUIDE PANEL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate, and more particularly, to a light guide plate capable of improving light efficiency and making luminance of emitted light uniform.

In general, the light guide plate changes the traveling direction (nearly parallel to the exit surface of the light guide plate) through the light incident surface provided on the side to emit the light to the exit surface. Such a light guide plate cannot obtain sufficient luminance because the light propagation plate cannot be used to switch the direction of light by using a simple transparent plate as it is.

Accordingly, the light guide plate is configured to include a reflective pattern of "V" shape for advancing the light traveling direction to the front surface of the light guide plate. Such a reflection pattern is formed in parallel with the light incident surface. At this time, the distance between the reflective patterns becomes narrower as the distance from the light incident surface becomes smaller, and the height of the reflective patterns on the back surface of the light guide plate is also formed to increase as the distance from the light incident surface increases.

Such a conventional light guide plate has a limitation in forming a reflective pattern because the distance between the reflective patterns must be formed differently according to the distance from the light source, and thus there is a limit in improving the brightness. As the area of the light guide plate increases, the efficiency decreases and There is a problem that the luminance is uneven. In addition, the conventional light guide plate has a problem that productivity is lowered because the height of the reflective pattern must be formed differently according to the distance from the light source.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and it is a technical object of the present invention to provide a light guide plate capable of improving the efficiency of light and making the luminance of emitted light uniform.

The light guide plate according to an embodiment of the present invention for achieving the above-described technical problem is a plate provided with a light incident surface on each side; And a plurality of reflective patterns formed concave on the rear surface of the plate to have a predetermined height to propagate light incident through the light entering surfaces toward the front of the plate, wherein the length of each reflective pattern is It is characterized by increasing gradually toward the central portion at each corner.

Each of the reflective patterns may include a first pattern formed in a horizontal direction of the plate; And a second pattern formed in the longitudinal direction of the plate to have a length shorter than the length of the first pattern.

The length of the second pattern is less than half of the length of the first pattern.

Each of the reflective patterns may include a first pattern formed along a horizontal direction of the plate; And a second pattern formed along a longitudinal direction of the plate, wherein at least one of the first and second patterns is formed to have a predetermined slope.

The first pattern is formed parallel to the horizontal direction of the plate to have a first length, the second pattern is characterized in that it is formed to have a second length shorter than the first length and to be inclined at a constant slope. .

The first pattern is formed to have a first length and to be inclined at a constant slope, and the second pattern is formed to be parallel to the longitudinal direction of the plate to have a second length shorter than the first length. .

The first and second patterns have different lengths and are inclined at a predetermined slope to have an "X" shape.

The first and second patterns have the same length and are inclined at a predetermined slope to have an "X" shape.

The length of the first pattern is increased toward the horizontal center line of the plate, the length of the second pattern is characterized by increasing toward the longitudinal center line of the plate.

The plurality of reflective patterns may be formed in a matrix form or staggered in a zigzag form along the horizontal and vertical directions.

The central portion of the second pattern is formed to cross the central portion of the first pattern.

The central portion of the second pattern is formed to cross the edge portion of the first pattern.

The second pattern may be formed to be connected to or spaced apart from a central portion or an edge portion of the first pattern.

The second pattern may include first and second divided patterns formed to be spaced apart from a central portion or an edge portion of the first pattern so as to be symmetrical about the first pattern.

The second pattern may be configured to include first and second divided patterns that are alternately formed to be connected to or spaced apart from an edge portion of the first pattern.

The present invention as described above has the following effects.

First, by forming a plurality of reflective patterns with the same height and width, and by making the length of the vertical pattern shorter than the horizontal pattern, it is possible to increase the brightness of the light to improve the efficiency of the light and at the same time make the brightness of the light uniform.

Second, by increasing the size of each reflective pattern toward the center of the plate gradually increases the brightness of the light to improve the efficiency of the light and at the same time the brightness of the light can be made uniform.

Third, since each reflective pattern has a constant width and height and is formed at regular intervals, productivity can be improved.

1 is a view for explaining a light guide plate according to a first embodiment of the present invention.

2 is a plan view schematically illustrating a horizontal pattern only to describe a reflective pattern according to an exemplary embodiment of the present invention.

3A is a cross-sectional view illustrating a cross section of a horizontal center line of the plate illustrated in FIG. 2.

3B is a cross-sectional view illustrating a cross section of the longitudinal center line of the plate illustrated in FIG. 2.

4 is a plan view schematically showing only a vertical pattern to explain a reflective pattern according to an exemplary embodiment of the present invention.

5 is a view for explaining a reflective pattern according to an embodiment of the present invention.

6 is a view for explaining a light guide plate according to another exemplary embodiment of the present disclosure.

7 to 12 are views for explaining another embodiment of each reflective pattern in the light guide plate according to the first embodiment of the present invention.

FIG. 13 is a diagram for describing a reflective pattern of a light guide plate according to a second exemplary embodiment of the present invention.

14 is a view for explaining another embodiment of the reflective pattern in the light guide plate according to the second embodiment of the present invention.

15 is a view for explaining a reflection pattern of the light guide plate according to the third embodiment of the present invention.

16 is a view for explaining a reflection pattern of the light guide plate according to the fourth embodiment of the present invention.

17 is a view for explaining another embodiment of a reflective pattern in the light guide plate according to the fourth embodiment of the present invention.

<Explanation of Signs of Major Parts of Drawings>

100: light guide plate

110: plate

120, 220, 320, 420: reflective patterns

122, 222, 322, 422: horizontal pattern

124, 224, 324, 424: vertical pattern

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining a light guide plate according to a first embodiment of the present invention.

1, a light guide plate 100 according to a first embodiment of the present invention includes a plate 110; And a plurality of reflective patterns 120.

Light is incident on the side surfaces of the plate 110 from the first to fourth light source parts 21, 22, 23, and 24. The plate 110 may be made of a translucent material in the form of a plate. In this case, each of the first to fourth light source parts 21, 22, 23, and 24 irradiates light to each side surface of the plate 110 using a light source such as a lamp or a light emitting diode (LED).

The plurality of reflective patterns 120 are formed in a matrix form on the rear surface of the plate 110 to have a predetermined interval and a predetermined height so that the light incident through each light incident surface is directed to the front surface of the plate 110.

To this end, each reflective pattern 120 has a horizontal pattern 122 formed in the horizontal direction of the plate 110 to have a first length; And a vertical pattern 124 formed in the longitudinal direction of the plate 110 to have a second length shorter than the first length.

2 is a plan view schematically illustrating a horizontal pattern only to describe a reflective pattern according to an exemplary embodiment of the present invention.

As shown in FIG. 2, the horizontal pattern 122 is formed in a matrix form to have a plurality of columns and rows on the rear surface of the plate 110. In this case, the horizontal pattern 122 is formed to have a first interval S1 along the horizontal direction of the plate 110 and to have a second interval S2 along the longitudinal direction of the plate 110. Here, the first interval S1 is preferably larger than the second interval S2.

In addition, as illustrated in FIG. 3A, the horizontal pattern 122 may have a concave shape to have a “-” shape and a cross section of a “V” shape as shown in FIG. 3B. have. At this time, the horizontal pattern 122 is formed to have the same height (H) and width (W) from the rear surface of the plate 110, regardless of the distance from the first to fourth light source (21, 22, 23, 24). do. Here, the horizontal pattern 122 may be easily formed through laser processing.

In addition, the first lengths 1L1 to 1L5 of the horizontal patterns 122 increase as the horizontal center line Ch of the plate 110 increases (1L1 <1L2 <1L3 <1L4 <1L5) and the plate 110. It increases toward the longitudinal center line (Cv) of. In this case, the first length of each horizontal pattern 122 is symmetrically about the horizontal center line Ch of the plate 110 and vertically symmetrically about the longitudinal center line Cv of the plate 110.

The horizontal pattern 122 of each of the reflective patterns 120 propagates the light incident through the light incident surface provided on the upper and lower surfaces of the plate 110 to the front surface of the plate 110. Accordingly, the light guide plate 100 may increase the luminance of the light and improve the uniformity through the horizontal pattern 122, the length of which increases as the distance from the light source increases.

4 is a plan view schematically showing only a vertical pattern to explain a reflective pattern according to an exemplary embodiment of the present invention.

As shown in FIG. 4, the vertical pattern 124 is formed in a matrix form to have a plurality of columns and rows on the rear surface of the plate 110. In this case, the vertical pattern 124 is formed to have a first interval S1 along the horizontal direction of the plate 110 and to have a second interval S2 along the longitudinal direction of the plate 110. Here, the first interval S1 is preferably larger than the second interval S2.

In addition, the vertical pattern 124 may have a concave shape such that the vertical pattern 124 has a “-” shape and a “V” shape like a cross section. In this case, the vertical patterns 124 are formed to have the same height and width from the rear surface of the plate 110 regardless of the distance from the first to fourth light source parts 21, 22, 23, and 24. Here, the vertical pattern 124 may be easily formed through laser processing.

In addition, the second length of each vertical pattern 124 increases toward the horizontal center line Ch of the plate 110 and increases toward the vertical center line Cv of the plate 110. In this case, the second length of each vertical pattern 124 is symmetrically about the horizontal center line Ch of the plate 110 and vertically symmetrically about the vertical center line Cv of the plate 110.

The vertical patterns 124 of each of the plurality of reflective patterns 120 propagate light incident through the light incident surfaces provided on the left and right surfaces of the plate 110 to the front surface of the plate 110. Accordingly, the light guide plate 100 may increase the luminance of the light and increase the uniformity through the vertical pattern 124, the length of which increases as the distance from the light source increases.

Each of the plurality of reflective patterns 120 described above is formed by combining the above-described horizontal pattern 122 and the vertical pattern 124. That is, each of the plurality of reflective patterns 120 is formed in a “+” shape as shown in FIG. 5 by crossing the center of the horizontal pattern 122 and the center of the vertical pattern 124. In this case, the second length 2L of the vertical pattern 124 is formed to be less than half of the first length 1L of the horizontal pattern 122.

As described above, according to the present invention, the lengths 1L and 2L of the plurality of reflective patterns 120 increase from the corners of the plate 110 toward the center of the plate 110 to increase the luminance of the light emitted from the light guide plate. It is possible to improve the efficiency and to make the luminance of the light uniform. In addition, the present invention can improve productivity because the reflective patterns 120 are formed at regular intervals and have a constant width and height.

Meanwhile, in the above-described light guide plate of the present invention, the plurality of reflective patterns 120 have been described as being formed in a matrix form to have a plurality of rows and columns, but the present invention is not limited thereto. As illustrated in FIG. It may be formed to be staggered in a zigzag form along the horizontal and vertical direction of the). When the plurality of reflective patterns 120 are formed in a zigzag form, the efficiency of light and the brightness of light may be more uniform than that of the matrix.

On the other hand, each reflective pattern 120 formed in the light guide plate of the present invention described above may be formed in various forms in addition to the "+" shape by the combination of the horizontal pattern 122 and the vertical pattern 124.

In another embodiment, in each of the reflective patterns 120, the center of the vertical pattern 124 is one edge of the horizontal pattern 122 (FIG. 7A) and the other side of the vertical pattern 124. It may be formed to be connected to the edge portion corresponding to any one of the edge (Fig. 7 (b)), one end (Fig. 7 (c)), and the other end (Fig. 7 (d)). Here, at least one reflective pattern 120 of (a) to (d) of FIG. 7 may be formed on the plate 110.

In another embodiment, in each of the reflective patterns 120, the vertical pattern 124 is a central portion of the horizontal pattern 122, as illustrated in FIG. 8 (FIG. 8A or FIG. 8B). It is formed to be connected to, or one edge (Fig. 8 (c) or (d)), the other edge (Fig. 8 (e) or (f)), one end (Fig. 8 (g) or (h)) , And may be formed to be connected to an edge portion corresponding to any one of the other ends ((i) or (j) of FIG. 8). Here, at least one reflective pattern 120 of FIGS. 8A to 8J may be formed on the plate 110.

In another embodiment, in each reflective pattern 120, the vertical pattern 124 is a central portion of the horizontal pattern 122, as illustrated in FIG. 9 (FIG. 9A or FIG. 9B). Formed adjacent to each other, or spaced apart from one side (FIG. 9 (c) or (d)), the other edge (FIG. 9 (e) or (f)), and one end (FIG. 9 (g) or (h). ), And the other end (i) or (j) of the other end may be formed adjacent to be spaced apart from the edge portion corresponding to. Here, at least one reflective pattern 120 of (a) to (j) of FIG. 9 may be formed on the plate 110.

In another exemplary embodiment, in each reflective pattern 120, the vertical pattern 124 may be formed to alternate between the first and second divided vertical patterns formed in the horizontal pattern 122, as illustrated in FIG. 10. 124a, 124b). In addition, the first divided vertical pattern 124a is formed to be connected to one side edge (a or b) of the horizontal pattern 122 or one end (c or d) of FIG. 10. Can be. Further, the second divided vertical pattern 124b is formed to be connected to the other edge (FIG. 10 (a) or (b)) or the other end (FIG. 10 (c) or (d)) of the horizontal pattern 122. Can be. Here, at least one reflective pattern 120 of FIGS. 10A to 10D may be formed on the plate 110.

In another embodiment, in each of the reflective patterns 120, the vertical patterns 124 are formed to be symmetrical with each other about the horizontal pattern 122, as illustrated in FIG. 11. It may be configured to include a pattern (124a, 124b). The first and second divided vertical patterns 124a and 124b may be formed adjacent to the center of the horizontal pattern 122 to be spaced apart from each other (FIG. 11A), or one side edge (FIG. 11B). It may be formed adjacent to the edge portion corresponding to any one of the other edge (Fig. 11 (c)), one end (Fig. 11 (d)), and the other end (Fig. 11 (e)). . Here, at least one reflective pattern 120 of (a) to (e) of FIG. 11 may be formed on the plate 110.

In another embodiment, in each of the reflective patterns 120, the vertical pattern 124 is formed adjacent to the horizontal pattern 122 and adjacent to the horizontal pattern 122, as shown in FIG. 12. The first and second divided vertical patterns 124a and 124b may be formed to cross each other. In addition, the first divided vertical pattern 124a is adjacent to be spaced apart from one side edge (FIG. 12 (a) or (b)) or one end (FIG. 12 (c) or (d)) of the horizontal pattern 122. Can be formed. Further, the second divided vertical pattern 124b is adjacent to be spaced apart from the other edge (FIG. 12 (a) or (b)) or the other end (FIG. 12 (c) or (d)) of the horizontal pattern 122. Can be formed. Here, at least one reflective pattern 120 of FIGS. 12A to 12D may be formed on the plate 110.

Meanwhile, in another embodiment, at least one reflective pattern 120 of the shapes illustrated in FIGS. 5 and 7 to 12 may be formed in a matrix or staggered in the plate 110. have.

FIG. 13 is a diagram for describing a plurality of reflective patterns 220 in the light guide plate according to the second exemplary embodiment of the present invention.

Referring to FIG. 13, each reflective pattern 220 of the LGP 100 according to the second exemplary embodiment may include a horizontal pattern 222 formed to be parallel to the long side direction of the plate 110; And a vertical pattern 224 formed to intersect the horizontal pattern 222 to have a predetermined slope.

Each horizontal pattern 222 is formed to be concave to have a "V" cross section on the back surface of the plate 110 to have a constant interval and a constant height, and is formed to be parallel to the long side direction of the plate 110 plate 110 The light incident through each light incident surface of) advances to the front surface of the plate 110. In this case, as described above, the length of each horizontal pattern 222 is formed to increase toward the central portion of the plate 110 (the further away from the light incident surface).

Each vertical pattern 224 is inclined at a constant slope to have a length shorter than the length of each horizontal pattern 222 so as to have a "V" cross section on the back of the plate 110 to intersect each horizontal pattern 222. It is formed concave to advance the light incident through each light incident surface of the plate 110 to the front of the plate (110). At this time, the length of each vertical pattern 224 is formed so as to increase from the corner portion of the plate 110 to the central portion of the plate 110 (farther from the light incident surface) as described above. In addition, the inclination of each vertical pattern 224 is preferably 45 degrees.

Accordingly, each vertical pattern 224 is formed to have a constant inclination so that each reflective pattern 220 is formed such that the length of the vertical pattern 224 has a shorter "X" shape than the horizontal pattern 222.

Meanwhile, each reflective pattern 220 of the light guide plate 100 according to the second embodiment of the present invention is formed in a matrix form as shown in FIG. 13 or alternately in a zigzag form as shown in FIG. 14. Can be formed.

As described above, the present invention increases the length of the plurality of reflective patterns 220 from each corner portion of the plate 110 toward the center of the plate 110 and forms the vertical pattern 224 at a constant inclination. By increasing the brightness of the light emitted from 100) it is possible to improve the light efficiency and to make the brightness of the light uniform. In addition, the present invention may improve productivity because each reflective pattern 220 has a constant width and height and is formed at regular intervals.

FIG. 15 is a diagram for describing a plurality of reflective patterns 320 in the light guide plate according to the third exemplary embodiment.

Referring to FIG. 15, each reflective pattern 320 of the LGP 100 according to the third exemplary embodiment may include a horizontal pattern 322 formed to have a predetermined slope on the plate 110; And a vertical pattern 324 formed to cross each horizontal pattern 322 and to be parallel to a short side direction of the plate 110.

As described above, each of the reflective patterns 320 includes the light guide plate 100 according to the second embodiment of the present invention, except that the horizontal pattern 322 is formed at a constant slope and the vertical pattern 324 is vertically formed. Each reflection pattern 220 provides the same effect.

Meanwhile, each reflective pattern 320 of the light guide plate 100 according to the third exemplary embodiment of the present invention may be formed in a matrix form or staggered in a zigzag form (not shown) as illustrated in FIG. 15. .

FIG. 16 is a diagram for describing a plurality of reflective patterns 420 in the light guide plate according to the fourth exemplary embodiment.

Referring to FIG. 16, each reflective pattern 420 of the light guide plate 100 according to the fourth exemplary embodiment of the present invention may include a horizontal pattern 422 formed to have a predetermined first slope on the plate 110; And a vertical pattern 424 intersecting each horizontal pattern 422 and formed to have a constant second slope on the plate 110.

Each horizontal pattern 422 is inclined at a first inclination so as to have a constant interval and a constant height is formed concave to have a "V" cross section on the back of the plate 110 through each light incident surface of the plate 110 The incident light is advanced to the front of the plate 110. In this case, as described above, the length of each horizontal pattern 422 is formed to increase toward the central portion of the plate 110 (the further away from the light incident surface).

Each vertical pattern 424 has a "V" cross section on the back surface of the plate 110 to be inclined at a second slope to have a length shorter than the length of each horizontal pattern 422 to intersect each horizontal pattern 422. It is formed to be concave so that light incident through each light incident surface of the plate 110 is advanced to the front of the plate (110). At this time, the length of each vertical pattern 424 is formed so as to increase from the corner portion of the plate 110 toward the central portion of the plate 110 (farther from the light incident surface) as described above. In addition, the inclination between the vertical pattern 424 and the horizontal pattern 422 is preferably 90 degrees.

Accordingly, each reflective pattern 420 is formed such that the length of the vertical pattern 424 has a "X" shape shorter than the horizontal pattern 422.

Meanwhile, each reflective pattern 420 of the light guide plate 100 according to the fourth exemplary embodiment of the present invention may be formed in a matrix form or staggered in a zigzag form (not shown) as illustrated in FIG. 16. .

As such, the present invention increases the lengths of the plurality of reflective patterns 420 from each corner portion of the plate 110 toward the center of the plate 110, and also keeps the horizontal pattern 422 and the vertical pattern 424 constant. By forming the inclination, the brightness of the light emitted from the light guide plate 100 may be increased to improve the light efficiency and to make the brightness of the light uniform. In addition, the present invention can improve productivity because each reflective pattern 420 has a constant width and height and is formed at regular intervals.

On the other hand, in the light guide plate 100 according to the fourth embodiment of the present invention, the vertical pattern 424 of each reflective pattern 420 is limited to have a length shorter than the length of the horizontal pattern 422 However, the present invention is not limited thereto, and the length of the horizontal pattern 422 may be shorter than the length of the vertical pattern 424.

Furthermore, in the light guide plate 100 according to the fourth embodiment of the present invention, each reflective pattern 420 has a length of the horizontal pattern 422 and the vertical pattern 424 as shown in FIG. 17. The same may be formed. Accordingly, each reflective pattern 220 has a horizontal pattern 422 and a vertical pattern 424 having the same length “X”. In this case, although the horizontal pattern 422 and the vertical pattern 424 of each reflective pattern 420 have the same length, the horizontal pattern 422 and the vertical pattern 424 of each reflective pattern 420 have a length plate. Since it is formed to increase toward each of the center portion of the plate 110 from each corner of the 110, it is possible to increase the brightness of the light emitted from the light guide plate 100 to improve the light efficiency and at the same time the brightness of the light.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

Claims (17)

delete delete delete Plates provided with light incident surfaces on each side; And A plurality of reflective patterns formed concave on the back surface of the plate to advance light incident through the light entering surfaces to the front surface of the plate, and having a same height as each other; Each reflective pattern having the same height is gradually increased in length from each corner portion of the plate toward the center portion, Each of the reflective patterns may include a first pattern formed in a horizontal direction of the plate; And a second pattern formed in the longitudinal direction of the plate to have a length shorter than the length of the first pattern. The method of claim 4, wherein The length of the second pattern is less than half the length of the first pattern of the light guide plate. Plates provided with light incident surfaces on each side; And A plurality of reflective patterns formed concave on the back surface of the plate to advance light incident through the light entering surfaces to the front surface of the plate, and having a same height as each other; Each reflective pattern having the same height is gradually increased in length from each corner portion of the plate toward the center portion, Each of the reflective patterns may include a first pattern formed along a horizontal direction of the plate; And a second pattern formed along a longitudinal direction of the plate, wherein at least one of the first and second patterns is formed to have a predetermined slope. The method of claim 6, The first pattern is formed parallel to the horizontal direction of the plate to have a first length, The second light guide plate is formed to have a second length shorter than the first length and to be inclined at a predetermined slope. The method of claim 6, The first pattern is formed to have a first length and to be inclined at a constant slope, The second light guide plate is formed in parallel with the longitudinal direction of the plate to have a second length shorter than the first length. The method of claim 6, The first and second patterns have different lengths and are inclined at a predetermined slope to have an "X" shape. The method of claim 6, The first and second patterns have the same length as each other, and the light guide plate is formed to be inclined at a constant slope to have an "X" shape. The method according to any one of claims 4 to 10, The length of the first pattern is increased toward the horizontal center line of the plate, the length of the second pattern is a light guide plate, characterized in that increases toward the longitudinal center line of the plate. The method according to any one of claims 4 to 10, The plurality of reflective patterns are formed in a matrix form, or are formed to be staggered in a zigzag form along the horizontal direction and the vertical direction. The method according to any one of claims 4 to 10, The central portion of the second pattern is formed to intersect the central portion of the first pattern. The method according to any one of claims 4 to 5, The central portion of the second pattern is formed to intersect the edge portion of the first pattern. The method according to any one of claims 4 to 5, The second light guide plate is formed to be connected to or spaced apart from the central portion or the edge portion of the first pattern. The method according to any one of claims 4 to 5, The second pattern includes a first light guide plate and a second divided pattern formed to be spaced apart from the central portion or the edge portion of the first pattern to be symmetrical about the first pattern. The method according to any one of claims 4 to 5, The second pattern is a light guide plate comprising a first and a second divided pattern formed to be alternately connected to each other so as to be connected to or spaced apart from the edge portion of the first pattern.