Foldable display device

Abstract

A foldable display device includes a reflective display panel, a light guide layer, and at least one light source. The light guide layer is located on the reflective display panel and includes a non-bending area, a bending area, and a junction area. The bending area is located in the middle of the light guide layer. The junction area is located between the bending area and the non-bending area. The light source is located on the reflective display panel and faces the sidewall of the non-bending area, and is configured to emit light to the light guide layer. Because the thickness of the non-bending area is greater than the thickness of the bending area, sufficient light input to the light guide layer is ensured. The smaller thickness of the bending area reduces the material rigidity of the bending area, allowing the foldable display device to fold at the bending area. The thickness of the junction area is between the non-bending area and the bending area, thus enabling total internal reflection of light from the light guide layer to the bending area. This ensures sufficient light input without requiring an additional light source and also improves the power efficiency of the foldable display device.

Description

Technical Field

[0001] This disclosure relates to a foldable display device. Background Art

[0002] Current light guide technologies have become quite mature and are not only applied to backlight display devices. Reflective display devices require mature light guide technologies even more. However, due to the rigidity problem of materials in light guide technologies, they are currently still limited to flat devices. If the light guide technology is to be applied to foldable devices, the overall thickness of the front light needs to be much smaller than the thickness of the light guide materials commonly used in flat panels, thereby reducing the material rigidity to achieve the purpose of being easily bent. For example, when evaluating the light guide material of a 10-inch reflective foldable device, under the condition of a folding radius of 4 mm, the light guide material needs to be 0.1 mm thick to possibly meet this bending condition. However, the thickness of the light guide material is proportional to the light emitting efficiency. If a considerable amount of light output is to be satisfied, the light guide material must also have a certain thickness, otherwise the number or power of the light sources needs to be increased. In this way, the power-saving advantage of the reflective display device is reduced. Therefore, how to design the thickness of the light guide material is an important topic in this field. Summary of the Invention

[0003] One technical aspect of this disclosure is a foldable display device.

[0004] In an embodiment of this disclosure, a foldable display device includes a reflective display panel, a light guide layer, and at least one light source. The light guide layer is located on the reflective display panel and includes a non-bending area, a bending area, and a transition area. The bending area is located in the middle part of the light guide layer. The transition area is located between the bending area and the non-bending area. The light guide layer satisfies the following relationships: D2 < D1, W2 ≧ Rxπ, and J1 ≦ (L - W2) / 2 - W1, where D1 is the thickness of the non-bending area, D2 is the thickness of the bending area, W1 is the width of the non-bending area, W2 is the width of the bending area, R is the folding radius of the reflective display panel, J1 is the width of the transition area, and L is the length of the light guide layer. The light source is located on the reflective display panel and faces the sidewall of the non-bending area, configured to emit light to the light guide layer.

[0005] In an embodiment of this disclosure, W1 = 0, and the continuous surface defined by the transition area and the bending area is a descending wedge shape.

[0006] In an embodiment of this disclosure, J1 < W1, and the continuous surface defined by the transition area and the bending area is concave.

[0007] In an embodiment of this disclosure, J1 = 0, and the continuous surface defined by the non-bending area and the bending area is stepped.

[0008] In an embodiment of the present disclosure, the light guide layer further includes a plurality of microstructures located on the top or bottom surface of the light guide layer and configured to interfere with or disrupt the total reflection of light entering the light guide layer.

[0009] In an embodiment of the present disclosure, the microstructures include at least one of a micro hot embossing wedge array pattern, a printed micro array pattern, non-uniform haze control particles, and non-uniform diffusion particles.

[0010] In an embodiment of the present disclosure, the number of light sources is two, and the two light sources are respectively oriented towards opposite sidewalls of the light guide layer.

[0011] In an embodiment of the present disclosure, the transition region is configured to transmit the light emitted by the light source to the bending region by total reflection.

[0012] Another aspect of the present disclosure is a foldable display device.

[0013] In an embodiment of the present disclosure, a foldable display device includes a reflective display panel and a light guide layer. The light guide layer is located on the reflective display panel, wherein the light guide layer has a plurality of microstructures configured to interfere with the total reflection of light in the light guide layer. The light guide layer further includes a non-bending region, a bending region, and a transition region. The bending region is located in the middle part of the light guide layer. The transition region is located between the bending region and the non-bending region. The light guide layer satisfies the following relationships: D2 < D1, W2 ≧ Rxπ, and J1 ≦ (L - W2) / 2 - W1, where D1 is the thickness of the non-bending region, D2 is the thickness of the bending region, W1 is the width of the non-bending region, W2 is the width of the bending region, R is the folding radius of the reflective display panel, J1 is the width of the transition region, and L is the length of the light guide layer.

[0014] In an embodiment of the present disclosure, W1 = 0, and the continuous surface defined by the transition region and the bending region is a descending wedge shape.

[0015] In an embodiment of the present disclosure, J1 < W1, and the continuous surface defined by the transition region and the bending region is concave.

[0016] In an embodiment of the present disclosure, J1 = 0, and the continuous surface defined by the non-bending region and the bending region is stepped.

[0017] In an embodiment of the present disclosure, the thickness of the transition region gradually decreases from the non-bending region towards the bending region.

[0018] In an embodiment of the present disclosure, the top surface of the transition region has a first part and a second part respectively adjacent to the non-bending region and the bending region, and the first part of the top surface is higher than the second part.

[0019] In one embodiment of this disclosure, the microstructure includes at least one of a micron-scale hot-pressed array pattern, a micron-scale inkjet printed pattern, unequal haze control particles, and unequal diffusion particles.

[0020] In the embodiments disclosed above, since the light guide layer includes three regions—a non-bending region, a bending region, and a junction region—and the thickness of the non-bending region is greater than the thickness of the bending region, sufficient light input can be ensured. Furthermore, the bending region of the light guide layer has a smaller thickness, reducing the material rigidity of the bending region, thus allowing the foldable display device to fold at the bending region. The thickness of the junction region of the light guide layer is between that of the non-bending region and the bending region, thus enabling total internal reflection to transmit light from the light guide layer to the bending region. This ensures sufficient light input without requiring an additional light source and also improves the power-saving effect of the foldable display device. Attached Figure Description

[0021] The nature of this disclosure can be best understood by reading it in conjunction with the accompanying illustrations and by the embodiments described below. Note that, according to standard practice in the industry, the various features are not drawn to scale. In fact, the dimensions of the various features may be increased or decreased arbitrarily for clarity of explanation.

[0022] Figure 1 A cross-sectional view of a foldable display device according to one embodiment of the present disclosure is shown;

[0023] Figure 2 Draw Figure 1 A cross-sectional view of a foldable display device when bent;

[0024] Figure 3A Draw Figure 1 A partial enlarged view of the light guide layer of a foldable display device;

[0025] Figure 3B A partially enlarged view of the light guide layer according to another embodiment of this disclosure is shown;

[0026] Figure 4 A cross-sectional view of a foldable display device according to another embodiment of this disclosure is shown;

[0027] Figure 5 A cross-sectional view of a foldable display device according to yet another embodiment of this disclosure is shown;

[0028] Figure 6 A cross-sectional view of a foldable display device according to another embodiment of the present disclosure is shown.

[0029] [Symbol Explanation]

[0030] 100, 100a, 100b, 100c: Foldable display devices

[0031] 110: Reflective display panel

[0032] 120, 120a, 120b, 120c: Light guide layer

[0033] 122, 122b, 122c: Non-bending areas

[0034] 124, 124a, 124b: Handover area

[0035] 126, 126a, 126b, 126c: Bending areas

[0036] 128, 128a: Microstructure

[0037] 130: Light source

[0038] 140: Optical transparent adhesive

[0039] D1, D2: Thickness

[0040] W1, W2, J1: Width

[0041] L: Total Length

[0042] R: Folding radius

[0043] P1: Part 1

[0044] P2: Part Two Detailed Implementation

[0045] The following description of embodiments provides numerous different implementations, or examples, for carrying out various features of the provided object. Specific examples of elements and arrangements are described below to simplify the subject matter. Of course, these examples are merely illustrative and are not intended to be limiting. Furthermore, element symbols and / or letters may be repeated in various examples. This repetition is for simplicity and clarity and does not in itself specify the relationship between the various embodiments and / or configurations discussed.

[0046] Spatial relative terms such as “below,” “under,” “lower,” “above,” and “upper” are used herein for descriptive purposes to describe the relationship between one element or feature and another, as shown in the accompanying drawings. Spatial relative terms are intended to cover different orientations of the apparatus in use or operation other than those shown in the accompanying drawings. The apparatus may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptors used herein shall be interpreted accordingly.

[0047] Figure 1 A cross-sectional view of a foldable display device 100 according to one embodiment of the present disclosure is shown. Figure 2 Draw Figure 1 Cross-sectional view of the foldable display device 100 when bent. Refer to Figure 1 and Figure 2 , the foldable display device 100 includes a reflective display panel 110, a light guide layer 120, and at least one light source 130. The light guide layer 120 is located on the reflective display panel 110 and includes a non-bending area 122, a bending area 126, and a junction area 124. The bending area 126 is located in the middle part of the light guide layer 120. The non-bending area 122, the bending area 126, and the junction area 124 are connected in sequence, so that the junction area 124 is located between the bending area 126 and the non-bending area 122. In addition, the light guide layer 120 satisfies the following relational expressions: D2 < D1, W2 ≥ Rxπ, and J1 ≤ (L - W2) / 2 - W1, where D1 is the thickness of the non-bending area 122, D2 is the thickness of the bending area 126, W1 is the width of the non-bending area 122, W2 is the width of the bending area 126, R is the folding radius of the reflective display panel 110, J1 is the width of the junction area 124, and L is the length of the light guide layer 120. As Figure 2 can be seen, the folding radius R of the reflective display panel 110 means the outer radius of the reflective display panel 110 of the foldable display device 100 in the bent state. The light source 130 is located on the reflective display panel 110 and faces the side wall of the non-bending area 122, and is configured to emit light to the light guide layer 120.

[0048] The light guide layer 120 of the foldable display device 100 satisfies the above three relational expressions. The first relational expression D2 < D1 means that the thickness D1 of the non-bending area 122 is greater than the thickness D2 of the bending area 126. In this way, the material rigidity of the bending area 126 is reduced, so the foldable display device 100 with this light guide layer 120 can be bent as Figure 2 shown. The second relational expression W_{2}\geq R\times\pi means that the width of the bending area 126 of the light guide layer 120 is greater than or equal to the total length of the area of the reflective display panel 110 below it that will be bent, that is, the folding radius R multiplied by the circumference ratio \(\pi\). As Figure 2As illustrated, when the foldable display device 100 is bent to its limit, the shape of the bent area of ​​its reflective display panel 110 can be a semi-circular arc. Therefore, the total length of the bent area of ​​the reflective display panel 110 is the folding radius R multiplied by pi (i.e., half the circumference of a circle). The width W2 of the bent area 126 of the light guide layer 120 must be greater than or equal to this value to ensure that the width W2 of the bent area 126 with low material rigidity is sufficient for the foldable display device 100 to bend. The width J1 of the junction area 124 of the light guide layer 120 can be described by the third relationship J1≦(L-W2) / 2-W1, that is, the width J1 of the junction area 124 can be less than or equal to half of the total length L of the light guide layer 120 minus the width W2 of the bending area 126 minus the width W1 of the non-bending area 122. This relationship means that the light guide layer 120 includes the non-bending area 122, the junction area 124 and the bending area 126, but may also include other areas.

[0049] Specifically, since the light guide layer 120 includes three regions: a non-bending region 122, a bending region 126, and a junction region 124, and the thickness D1 of the non-bending region 122 is greater than the thickness D2 of the bending region 126, sufficient light input can be ensured in the light guide layer 120. Furthermore, the smaller thickness D2 of the bending region 126 reduces the material rigidity of the bending region 126, allowing the foldable display device 100 to fold at the bending region 126. The thickness of the junction region 124 of the light guide layer 120 is between that of the non-bending region 122 and the bending region 126, allowing light from the light guide layer 120 to be transmitted to the bending region 126 via total internal reflection. This ensures sufficient light input without requiring an additional light source 130, and also improves the power efficiency of the foldable display device 100.

[0050] In some embodiments, the number of light sources 130 may be multiple, for example, two, with each light source 130 facing opposite sidewalls of the light guide layer 120 and configured to emit light onto the light guide layer 120. That is, the light guide layer 120 may be located between the two light sources 130. The thickness D1 of the non-bending region 122 of the light guide layer 120 may be equal to the thickness of the emitting surface of the light source 130, which is beneficial for a flattened design around the foldable display device 100, but is not intended to limit this disclosure. In other embodiments, the thickness D1 of the non-bending region 122 may also be greater than or less than the thickness of the emitting surface of the light source 130. The junction region 124 is configured to transmit the light emitted by the light source 130 to the bending region 126 via total internal reflection. In this embodiment, the thickness of the junction region 124 gradually decreases from the non-bending region 122 to the bending region 126. This design allows the non-bending area 122, with its large light-receiving surface, to receive light from the light source 130 and transmit it to the bending area 126 via the junction area 124. The sufficiently large light-receiving surface of the non-bending area 122 ensures good luminous efficiency, while the low material rigidity of the bending area 126 allows the foldable display device 100 to be bent from the bending area 126. The junction area 124 ensures that light entering the light guide layer 120 can be transmitted to the bending area 126, ensuring high luminous efficiency in all areas.

[0051] Figure 3A Draw Figure 1 A partially enlarged view of the light guide layer 120 of the foldable display device 100. (Refer to...) Figure 3A The light guide layer 120 also includes a plurality of microstructures 128. In this embodiment, the microstructures 128 are located on the top surface of the light guide layer 120 and are configured to interfere with or disrupt total internal reflection of light entering the light guide layer 120. The microstructures 128 include at least one of a micron-scale hot-pressed wedge array pattern, a spray-printed micron array pattern, unequal haze control particles, and unequal diffusion particles, but other methods may also be used to fabricate the microstructures 128. Figure 3A In this process, the light guide layer 120 can be attached to the reflective display panel 110 using optically transparent adhesive 140. Microstructures 128 are distributed throughout the light guide layer 120 and can be located in the non-bending area 122, the bending area 126, and the junction area 124. The microstructures 128 can interfere with or disrupt the total internal reflection of light entering the light guide layer 120, thereby allowing light energy to be transmitted to its destination.

[0052] Figure 3B A partially enlarged view of the light guide layer 120 according to another embodiment of this disclosure is shown. This embodiment is similar to... Figure 3A The difference in implementation methods lies in, Figure 3BThe microstructure 128a is located on the bottom surface of the light guide layer 120. The microstructure 128a includes at least one of a micro hot embossed wedge array pattern, an inkjet printed microarray pattern, non-uniform haze control particles, and non-uniform diffusion particles. However, the microstructure 128a can also be fabricated in other ways. In addition, the microstructure 128a on the bottom surface of the light guide layer 120 can be located in the optical transparent adhesive 140.

[0053] The above Figure 3A The microstructure 128 and Figure 3B The microstructure 128a can be selectively applied to Figure 1 , Figure 4 , Figure 5 , Figure 6 in the embodiments of

[0054] Figure 4 FIG. shows a cross-sectional view of a foldable display device 100a according to another embodiment of the present disclosure. The foldable display device 100a includes a reflective display panel 110, a light guide layer 120a, and at least one light source 130. In this embodiment, the light guide layer 120a of the foldable display device 100a does not have a non-bending region 122 as Figure 1 In other words, the width W1 of the non-bending region of the light guide layer 120a is 0. In addition, the continuous surface defined by the junction region 124a and the bending region 126a is in a descending wedge shape. In this embodiment, the side wall of the junction region 124a can directly receive the light emitted by the light source 130 and transmit the light emitted by the light source 130 to the bending region 126a, and similar effects to the previous embodiments can also be achieved.

[0055] Figure 5 FIG. shows a cross-sectional view of a foldable display device 100b according to yet another embodiment of the present disclosure. The foldable display device 100b includes a reflective display panel 110, a light guide layer 120b, and at least one light source 130. In this embodiment, the width W1 of the non-bending region 122b of the light guide layer 120b of the foldable display device 100b is greater than the width J1 of the junction region 124b, that is, J1 < W1, and the continuous surface defined by the junction region 124b and the bending region 126b is concave. The top surface of the junction region 124b has a first portion P1 and a second portion P2 that are respectively adjacent to the non-bending region 122b and the bending region 126b, and the first portion P1 of the top surface is higher than the second portion P*.

[0056] Figure 6 FIG. shows a cross-sectional view of a foldable display device 100c according to still another embodiment of the present disclosure. The foldable display device 100c includes a reflective display panel 110, a light guide layer 120c, and at least one light source 130. In this embodiment, the light guide layer 120c of the foldable display device 100c does not have a non-bending region as Figure 1The width J1 of the junction area 124, which is the junction area of ​​the light guide layer 120a, is 0. Furthermore, the continuous surface defined by the non-bending area 122c and the bending area 126c is stepped. That is, in this embodiment, there is no surface with a thickness gradient between the non-bending area 122c and the bending area 126c of the foldable display device 100c. The stepped surface of the light guide layer 120b achieves similar effects to other embodiments.

[0057] The foregoing outlines the features of several embodiments to enable those skilled in the art to better understand the nature of this disclosure. Those skilled in the art should understand that they can readily use this disclosure as the basis for designing or modifying other processes and structures to achieve the same purposes and / or advantages as the embodiments described herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and alterations can be made to them without departing from the spirit and scope of this disclosure.

Claims

1. A foldable display device, characterized in that, Comprising: A reflective display panel; A light guide layer located on the reflective display panel, comprising: A non-bending area; A bending area located in the middle part of the light guide layer; and A transition area located between the bending area and the non-bending area, and the light guide layer satisfies the following relational expressions: D2 < D1, W2 ≥ Rxπ, and J1 ≤ (L - W2) / 2 - W1, where D1 is the thickness of the non-bending area, D2 is the thickness of the bending area, W1 is the width of the non-bending area, W2 is the width of the bending area, R is the folding radius of the reflective display panel, J1 is the width of the transition area, and L is the length of the light guide layer; And At least one light source located on the reflective display panel and facing the side wall of the non-bending area, configured to emit a light ray to the light guide layer.

2. The foldable display device as claimed in claim 1, characterized in that, W1 = 0, and the continuous surface defined by the transition area and the bending area is in a descending wedge shape.

3. The foldable display device as claimed in claim 1, characterized in that, J1 < W1, and the continuous surface defined by the transition area and the bending area is concave.

4. The foldable display device as claimed in claim 1, characterized in that, J1 = 0, and the continuous surface defined by the non-bending area and the bending area is stepped.

5. The foldable display device as claimed in claim 1, characterized in that, The light guide layer further comprises: A plurality of microstructures located on the top surface or the bottom surface of the light guide layer, configured to interfere with or disrupt the total reflection of the light ray entering the light guide layer.

6. The foldable display device as claimed in claim 5, characterized in that, The plurality of microstructures includes at least one of a micro hot embossing wedge array pattern, a spray-printed micro array pattern, unequal haze control particles, and unequal diffusion particles.

7. The foldable display device as claimed in claim 1, characterized in that, The number of the light sources is two, and the two light sources respectively face the opposite side walls of the light guide layer.

8. The foldable display device as claimed in claim 1, characterized in that, The transition area is configured to transmit the light ray emitted by the light source to the bending area by total reflection.

9. A foldable display device, characterized in that, Comprising: A reflective display panel; and A light guide layer located on the reflective display panel, wherein the light guide layer has a plurality of microstructures configured to interfere with the total reflection of the light ray in the light guide layer, and the light guide layer further comprises: A non-bending area; A bending area located in the middle part of the light guide layer; and A transition area located between the bending area and the non-bending area, and the light guide layer satisfies the following relational expressions: D2 < D1, W2 ≥ Rxπ, and J1 ≤ (L - W2) / 2 - W1, where D1 is the thickness of the non-bending area, D2 is the thickness of the bending area, W1 is the width of the non-bending area, W2 is the width of the bending area, R is the folding radius of the reflective display panel, J1 is the width of the transition area, and L is the length of the light guide layer.

10. The foldable display device as claimed in claim 9, characterized in that, W1 = 0, and the continuous surface defined by the transition area and the bending area is in a descending wedge shape.

11. The foldable display device as claimed in claim 9, characterized in that, J1 < W1, and the continuous surface defined by the transition area and the bending area is concave.

12. The foldable display device as claimed in claim 9, characterized in that, J1 = 0, and the continuous surface defined by the non-bending area and the bending area is stepped.

13. The foldable display device as claimed in claim 9, characterized in that, The thickness of the transition area gradually decreases from the non-bending area to the bending area.

14. The foldable display device as claimed in claim 9, characterized in that, The top surface of the transition area has a first part and a second part respectively adjacent to the non-bending area and the bending area, and the first part of the top surface is higher than the second part.

15. The foldable display device as claimed in claim 9, characterized in that, The plurality of microstructures includes at least one of a micro hot embossing array pattern, a spray-printed micro array pattern, unequal haze control particles, and unequal diffusion particles.

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