TWI530719B - Light guide plate and display apparatus of using the light guide plate - Google Patents

Description

Light guide plate and display device using the same

The present invention relates to a light guide plate and a display device using the same.

The liquid crystal display panel is a non-self-illuminating display device. Therefore, in order to achieve the display effect, the external light source is mainly guided to the liquid crystal display panel through a backlight or a front light module to realize the display function.

The main components of the general lateral backlight module are at least: a light source and a light guide plate. The light source is usually a point source or a line source, and a point source such as a light emitting diode (LED). The light guide plate is used to guide the direction of the light. The light source enters the light guide plate from the side (incident surface) of the light guide plate, and is reflected and scattered through a reflective surface of the light guide plate to form uniform scattered light in all aspects and emit light from the light guide plate. The surface leaves the liquid crystal display panel to provide a flat light with a uniform distribution of the liquid crystal display panel.

In the past, as the size of the liquid crystal display panel is getting larger and larger, in practice, on the premise of cost consideration, a plurality of light-emitting diodes are arranged in a line-like light bar to replace the conventional line source. However, when the light provided by the point light source is incident on the light incident surface of the light guide plate, a phenomenon of alternating bright and dark is easily generated, which is generally called a hot spot in the industry, which causes uneven light emission of the light guide plate.

Therefore, how to provide a light guide plate capable of improving hot spots, rapid mass production, easy adjustment of microstructure distribution and shape, shortening of microstructure process timing, and low cost is one of the problems urgently needed to be solved in the field.

It is an object of the present invention to provide a light guide plate which can improve hot spots, can be mass-produced quickly, can easily adjust the microstructure distribution and shape, shorten the microstructure process timing, and is inexpensive, and a display device using the same.

To achieve the above object, the light guide plate of the present invention comprises a plate body and a plurality of microstructures. The plate body has a light incident surface. A plurality of microstructures are formed on the light incident surface, and at least one of the adjacent microstructures overlaps each other in the first direction.

The present invention further provides a display device including a first substrate, a second substrate, a display medium, and a backlight module. The second substrate is disposed opposite to the first substrate. The display medium is disposed between the first substrate and the second substrate. The backlight module is disposed on a side of the first substrate away from the second substrate.

The backlight module includes a light guide plate and at least one light source, and the light source is disposed corresponding to the light incident surface of the light guide plate. The light guide plate has a plate body and a plurality of microstructures. A plurality of microstructures are formed on the light incident surface of the light guide plate, and overlap with at least one of the microstructures in the first direction.

In one embodiment, the microstructures each have a geometric center, and the microstructures each have a width and a height, and the distance from the geometric center of the adjacent microstructures in the first direction is between 0.01 mm and 0.05 mm. between.

In an embodiment, the heights of the at least one adjacent microstructures are different in the first direction.

In an embodiment, the at least one adjacent microstructures overlap each other in the second direction, and the second direction is substantially perpendicular to the first direction.

In one embodiment, the microstructure to height to microstructure width ratio is between 0.2 and 0.6.

In an embodiment, the light incident surface forms a first roughened region and a second roughened region. Moreover, the heights of the microstructures located in the first rough region are greater than the heights of the microstructures located in the second roughness region.

In summary, the present invention forms a plurality of microstructures on the light incident surface of the light guide plate by means of inkjet or coating, which can process a plurality of light guide plates in batches and in large quantities, and achieve rapid and large-scale production. The advantages of shortening the microstructure process timing.

In addition, compared to mechanical processing, inkjet or coating methods can be adjusted according to the needs of different products, without the need to adjust the tool model. In addition, the present invention can achieve the effect of improving hot spots through the microstructures overlapping each other.

1‧‧‧Backlight module

21‧‧‧First substrate

22‧‧‧second substrate

23‧‧‧ Display media

10, 30, 40, 50, 60‧‧‧ light guides

12a, 32, 42, 52, 62‧‧‧ into the glossy surface

12b‧‧‧Glossy

14, 34, 34a, 34b, 44, 44a, 44b, 54, 64‧‧‧ microstructures

321a‧‧‧First rough area

321b‧‧‧second rough zone

141, 541‧‧ ‧ geometric center

D‧‧‧distance

D‧‧‧Microstructure width

L‧‧‧Light source

H‧‧‧Microstructure height

X‧‧‧ first direction

Y‧‧‧second direction

1 is a schematic view of a display device of the present invention.

2A is a perspective view of a first embodiment of a light guide plate with a light emitting diode according to the present invention.

2B is a partial enlarged view of FIG. 2A.

2C is a top plan view of FIG. 2B.

Figure 2D is an enlarged schematic view of a single microstructure.

Figure 2E is a plot of the ratio of microstructure height to microstructure width versus energy loss.

3 is a partially enlarged schematic view showing a second embodiment of the light guide plate with the light emitting diode of the present invention.

4 is a partially enlarged schematic view showing a third embodiment of the light guide plate with the light emitting diode of the present invention.

Fig. 5A is a perspective view showing a fourth embodiment of the light guide plate of the present invention in combination with the light emitting diode.

Fig. 5B is a partially enlarged schematic view of Fig. 5A.

FIG. 5C is a top plan view of FIG. 5B.

Figure 5D is a plot of the sum of the widths of different adjacent microstructures and energy loss.

FIG. 5E is a distance-energy relationship diagram of the conventional light guide plate of the present embodiment. FIG.

Fig. 6A is a partially enlarged schematic view showing a fifth embodiment of the light guide plate of the present invention.

FIG. 6B is a distance-energy relationship diagram of the conventional light guide plate of the present embodiment. FIG.

Hereinafter, a light guide plate and a display device to which the light guide plate is applied according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals. In addition, the illustrations of all the embodiments of the present invention are merely schematic and do not represent true dimensions and proportions.

Please refer to FIG. 1 together. FIG. 1 is a schematic diagram of a display device of the present invention.

The display device of this embodiment includes a backlight module 1, a first substrate 21, a second substrate 22, and a display medium 23. The second substrate 22 is disposed opposite to the first substrate 21. The display medium 23 is disposed between the first substrate 21 and the second substrate 22. The backlight module 1 is disposed on a side of the first substrate 21 away from the second substrate 22 .

The backlight module 1 includes a light guide plate 10 and at least one light source L. The light source L is disposed corresponding to the light incident surface 12a of the light guide plate 10. The detailed structure of the light guide plate 10 will be described later.

Through the light guide plate 10, the light provided by the light source L can enter the light guide plate 10, exit from the light exit surface 12b of the light guide plate 10, and sequentially enter the first substrate 21, the display medium 23, and the second substrate 22, and then leave the display device to realize display. The function.

2A to 2E, which are respectively a perspective view of a first embodiment of a light guide plate with a light-emitting diode of the present invention, a partial enlarged view of FIG. 2A, a top view of FIG. 2B, and a single microstructure. A magnified view and a plot of the ratio of microstructure height to microstructure width versus energy loss.

The light guide plate 10 of the embodiment includes a plate body and a plurality of microstructures 14. A plurality of microstructures 14 are formed on the light incident surface 12a of the light guide plate 1. The light source L to which the light guide plate 10 is disposed is located on the light incident surface 12a side, and the light beam will enter the light guide plate 10 from the light incident surface 12a.

The light guide plate 10 of the embodiment can be a light transmissive plate body and used with at least one light source L. The light source L can be, for example, a light emitting diode.

The microstructures 14 are formed by inkjet or ink coating. And the ink material can have photocuring properties. Therefore, the ink material further includes a sensitizer. For example, the ink material of this embodiment may be polymethylmethacrylate (PMMA). Therefore, the ink will be solidified after being formed on the light incident surface to form the microstructures 14. Since the ink material of the present embodiment is a photocurable material, a plurality of microstructures 14 can be formed by irradiating UV light.

The microstructures 14 of the embodiment are identical in shape and size, and are evenly distributed on the light incident surface 12a. In addition, the number of the microstructures 14 and the number of columns of the drawing are referred to, and are not limited thereto.

If the inkjet method is adopted, the ink can be ejected along the track through the driving device, and a plurality of light guide plates can be arranged adjacent to each other in the operation, and the light incident surfaces of the light guide plates are processed together. In this way, batches, a large number of processing of a plurality of light guide plates can be achieved, and a rapid mass production and shortening of the microstructure process timing can be achieved.

The above manufacturing method can adjust the height of the microstructure by changing the surface of the light surface according to different hot-spot processing costs and different hot spots according to different product lines, without being as conventional The machining process needs to be specially matched with different fixtures, so the manufacturing method provided by the embodiment is simpler. In addition, in view of the limitations of the machined equipment, the size of the processed microstructure is also limited, and the ink formed by the inkjet method as in this embodiment The microstructure size of the material is not limited to this, so that a smaller size microstructure can be provided and the design is more flexible.

However, when the light guide plate 10 of the present embodiment is actually applied, a plurality of light emitting diodes can be matched, and the light beams generated by the light emitting diodes can enter the microstructures 14 from the light incident surface 12a of the light guide plate 10. The divergence angle of the beam will increase to improve or avoid hot spots generated when applying a point source.

It is to be noted that, preferably, the ink material may be selected from the same or similar refractive index as the light guide plate 10, so that the light will not pass through the light guide plate 10 and the microstructure when the light penetrates the microstructures 14 into the light guide plate 10. 14 is a different medium, causing loss of light coupling.

The detailed features of the microstructures will be described below. Specifically, for the sake of clarity and clarity in the following drawings, the number of columns of the microstructures 14 in the X direction (first direction) is exemplified by only three columns, but The actual application is not limited to three columns.

Referring to FIG. 2C, the microstructure 14 of the present embodiment has a geometric center 141. To facilitate understanding of the subsequent adjustment of the microstructure, the present embodiment defines the distance from the orthographic projection of the geometric center 141 to the light incident surface 12a as the microstructure height H. And each of the microstructures 14 has a microstructure width D. Taking the microstructure 14 as a circle as an example, the microstructure width D is the diameter of the microstructure 14.

Moreover, when the microstructure height H and the microstructure width D ratio of each of the microstructures 14 are between 0.2 and 0.6, the effect of improving the hot spot is more significant (compared with the highest energy and lowest point of the point light source of the prior art) The difference in energy is small, and the most significant is the ratio of the microstructure height H to the microstructure width D of 0.3. It can be seen from FIG. 2E that even if a plurality of microstructures 14 are disposed on the light-incident surface 12a, the overall energy consumption is not significant, so that the microstructures 14 can be disposed through the entire energy loss. The design of the smooth surface 12a increases the divergence angle of the light source to achieve the purpose of improving the hot spot.

Those having ordinary knowledge in the art should be aware of the above, and the so-called hot spot here is a phenomenon in which the brightness distribution on the light guide plate is uneven, and will not be described in the following paragraphs.

Next, please refer to FIG. 3, FIG. 4, FIG. 3 and FIG. 4 are partial enlarged views of the second and third embodiments of the light guide plate with the light-emitting diode of the present invention.

Similar to the first embodiment, the light guide plate 30 of the second embodiment includes a plate body and a plurality of microstructures 34. The plate body has a light incident surface 32. The microstructures 34 are formed on the light incident surface 32. The light guide plate 40 of the third embodiment includes a plate body and a plurality of microstructures 44. The plate body has a light incident surface 42. The microstructures 44 are formed on the light incident surface 42.

However, the difference from the first embodiment is that the second and third embodiments differ in the microstructure height H of each of the microstructures adjacent in the X direction (first direction).

Furthermore, the second embodiment is such that the height H of the microstructures 34a in the middle row is higher than the height H of the microstructures 34b adjacent to the light incident surface 32. Contrary to the second embodiment, the third embodiment has the height H of the microstructures 44a in the middle row being lower than the height H of the microstructures 44b adjacent to the light entrance surface 42.

The manner of adjusting the height H of the microstructure can be changed by changing the roughness of the light-incident surfaces 32, 42 so that the surface tension is changed. In short, the microstructures having different microstructure heights H are on the light-incident surfaces 32, 42. The roughness of the position is also different.

For example, taking the second embodiment as an example, the light incident surface 32 may be formed into a first rough region 321a and a second rough region 321b. For example, the first rough region 321a may be coated with a siloxane, a polyaminic acid, a polyimine, a fluoropolymer or a combination thereof such that the roughness of the first rough region 321a is greater than that of the second rough region 321b. The roughness, therefore, the height of the microstructures 34 formed in the first rough region 321a is higher than the microstructures 34 formed in the second roughness region 321b.

When the experimental conditions are: the microstructure is slightly arranged in the X direction with 13 columns, the diameter of the microstructure is 0.05 mm, and the higher microstructure height H is 0.015 mm, and the lower microstructure height H is 0.01 mm. The case of PCT. The experimental examples optimized at this time are eleven columns of higher microstructures 34a with a lower column of microstructures 34b, and a column of lower microstructures 44b with twelve columns of higher microstructures 44a.

The remaining component configurations and effects are similar to those of the first embodiment and will not be described again.

5A, FIG. 5B, and FIG. 5C are respectively a perspective view, a partially enlarged schematic view, and a top plan view of a fourth embodiment of a light guide plate with a light-emitting diode according to the present invention. Figure 5D is a plot of the sum of adjacent microstructure widths and energy loss. FIG. 5E is a position-energy relationship diagram of the conventional light guide plate of the present embodiment. FIG.

Similar to the first embodiment, the light guide plate 50 of the fourth embodiment includes a plate body and a plurality of microstructures 54. The plate body has a light incident surface 52. The microstructures 54 are formed on the light incident surface 52.

However, the difference from the first embodiment lies in the X direction of the first embodiment (first The distance of the adjacent geometric centers 141 of the microstructures 14 (the shortest distance between two adjacent central regions) is equal to or greater than the sum of the microstructure widths of adjacent microstructures. In short, the microstructures 14 of the first embodiment are not overlapped with each other in the X direction (first direction). The distance d between the geometric centers 541 of the adjacent microstructures 54 of the present embodiment is smaller than the sum of the microstructure widths of the microstructures adjacent to each other in the X direction. In short, the microstructures 54 of the present embodiment are arranged in an overlapping manner in the X direction (first direction). And the distance between the geometric centers 541 of the microstructures 54 adjacent in the X direction (first direction) is between 0.01 mm and 0.05 mm.

When the microstructure width is 0.05 mm and the geometric center 541 is 0.05 mm, the performance of the improvement hot spot is better. As can be seen from FIG. 5D, adjusting the degree of overlap of adjacent microstructures will not have a significant impact on the overall energy consumption, so that the at least partially overlapping portion can be disposed in the case where the overall energy consumption is not significant. The microstructures 54 are on the light incident surface 52 such that the divergence angle of the light source L is increased to achieve the purpose of improving the hot spot.

FIG. 5E further shows the performance of the single light-emitting diode of the geometric center 541 of the adjacent microstructures of 0.05 mm in the light guide plate and the prior art (that is, without any structure on the light-incident surface). The performance of the single light-emitting diodes is compared in the performance of the light guide plate. As can be seen from the figure, the high brightness of the present embodiment tends to be lower in brightness (the dotted line in the figure), that is, the difference between light and dark is less significant. Therefore, it can improve hot issues.

The remaining component configurations and effects are similar to those of the previous embodiment and will not be described again.

Finally, please refer to FIG. 6A and FIG. 6B together, which are respectively a partially enlarged schematic view of a fifth embodiment of the light guide plate of the present invention and a position-energy relationship diagram of the light guide plate of the present embodiment.

The light guide plate 60 of the fifth embodiment includes a plate body and a plurality of microstructures 64. The plate body has a light incident surface 62. The microstructures 64 are formed on the light incident surface 62. In this embodiment, in addition to defining the X direction (first direction), the Y direction (second direction) may be defined, and the Y direction is substantially perpendicular to the X direction.

The difference from the fourth embodiment is that the microstructures 64 of the present embodiment overlap in the Y direction (the second direction) except that they overlap in the X direction (first direction). Further, the distance between the geometric centers of the microstructures 64 adjacent to each other in the Y direction of the present embodiment is smaller than the sum of the microstructure widths of the microstructures 64 adjacent to each other in the Y direction.

The remaining component configurations and effects are similar to those of the previous embodiment and will not be described again.

In summary, the present invention forms a plurality of microstructures on the light incident surface of the light guide plate by means of inkjet or coating, which can process a plurality of light guide plates in batches and in large quantities, and achieve rapid and large-scale production. The advantages of shortening the microstructure process timing.

In addition, compared to mechanical processing, inkjet or coating methods can be adjusted according to the needs of different products, without the need to adjust the tool model. In addition, the present invention can achieve the effect of improving hot spots through the microstructures overlapping each other.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

50‧‧‧Light guide plate

52‧‧‧Into the glossy surface

54‧‧‧Microstructure

L‧‧‧Light source

X‧‧‧ first direction

Y‧‧‧second direction

Claims (10)

A light guide plate comprising: a plate body having a light incident surface; and a plurality of microstructures formed on the light incident surface, the microstructures being at least adjacent to each other in a first direction and a second direction The microstructures overlap each other. The light guide plate of claim 1, wherein the microstructures each have a geometric center, and each of the microstructures has a width and a height, and the geometry of the adjacent microstructures in the first direction The center distance is between 0.01 mm and 0.05 mm. The light guide plate of claim 2, wherein the height of the at least one adjacent microstructure is different in the first direction. The light guide plate of claim 2, wherein the second direction is perpendicular to the first direction. The light guide plate of claim 2, wherein each of the microstructure heights and each of the microstructure width ratios is between 0.2 and 0.6. The light guide plate of claim 1, wherein the light incident surface forms a first rough region and a second rough region, and the heights of the microstructures located in the first rough region are greater than the second rough region. The height of the microstructures. A display device includes: a first substrate; a second substrate disposed opposite to the first substrate; a display medium disposed between the first substrate and the second substrate; and a backlight module disposed on the The backlight module includes: a light guide plate having a plate body and a plurality of microstructures, wherein the microstructures are formed on a light incident surface of the light guide plate, and The microstructures and the at least one adjacent microstructures overlap each other in the first direction and the second direction; and at least one light source is disposed corresponding to the light incident surface of the light guide plate. The display device of claim 7, wherein the microstructures each have a geometric center, and the microstructures each have a width and a height, adjacent to the first direction The geometric center of the microstructures has a distance between 0.01 mm and 0.05 mm. The display device of claim 8, wherein the height of the at least one adjacent microstructure is different in the first direction. The display device of claim 8, wherein the second direction is perpendicular to the first direction.