CN118671875A - Light source module and reflective display device - Google Patents

Abstract

The present invention provides a light source module and a reflective display device, wherein the light source module comprises a flexible circuit substrate, a light emitting element, and a light guide film. The light emitting element and the light guide film are located on the flexible circuit substrate and are both located on the same side of the flexible circuit substrate. The light emitting surface of the light emitting element faces the light guide film, wherein there is a width between an edge of the light emitting surface farthest from the flexible circuit substrate and another edge of the light emitting surface closest to the flexible circuit substrate. In addition, the light guide film has a thickness, and the width of the light emitting surface does not exceed four times the thickness. By limiting the thickness of the light guide film and the light emitting surface, the light coupling efficiency is improved.

Description

Light source module and reflective display device

Technical Field

The present invention relates to a light source module and a display device using the light source module, and in particular to a reflective display device and a light source module thereof.

Background Art

As flexible displays become thinner, in order to significantly reduce the thickness of the display, the size of various components inside the display must be reduced. For example, the light source module inside the display usually includes a light guide plate, and the thickness of the display can be reduced by reducing the thickness of the light guide plate to meet the trend of thinning flexible displays.

The current industry development has applied thinned light guide plates (i.e. light guide films; LGF) to the light source modules of reflective display devices. In the light source module of a reflective display, light is emitted from the light-emitting surface of the light source (e.g., light-emitting diode; LED) and enters the light guide film through the light-incident surface on the side of the light guide film.

However, since the light-entering surface of the light-guiding film is much smaller than the light-emitting surface of the light source, the sizes of the two are difficult to match, resulting in reduced light coupling efficiency. In addition, the size difference between the light-entering surface of the light-guiding film and the light-emitting surface of the light source also deepens the difficulty of aligning the light-emitting surface with the light-entering surface during assembly, thus causing optical defects and further affecting the image quality of the display.

Summary of the invention

An embodiment of the present invention provides a light source module, wherein the width of the light emitting surface of the light source module is no more than four times the thickness of the light incident surface of the light guide film, so as to improve the light coupling efficiency of the light source module.

An embodiment of the present invention provides a reflective display device, comprising the light source module mentioned above.

In at least one embodiment of the present invention, the light source module includes a flexible circuit substrate; a light emitting element located on the flexible circuit substrate; and a light guide film located on the flexible circuit substrate. The light guide film and the light emitting element are both located on the same side of the flexible circuit substrate, and a first light emitting surface of the light emitting element faces the light guide film. There is a width between an edge of the first light emitting surface farthest from the flexible circuit substrate and another edge of the first light emitting surface closest to the flexible circuit substrate. The light guide film has a thickness, and the width of the first light emitting surface does not exceed four times the thickness.

In at least one embodiment of the present invention, the thickness of the light guide film is no greater than 100 μm.

In at least one embodiment of the present invention, the light source module further includes a light shielding film located on the light guiding film, wherein the light shielding film and the flexible circuit substrate are respectively located on two opposite sides of the light guiding film.

In at least one embodiment of the present invention, the light shielding film covers a top surface of the light emitting element.

In at least one embodiment of the present invention, the light-shielding film includes a black light-shielding layer and a white light-shielding layer located between the black light-shielding layer and the light-guiding film, and the white light-shielding layer has light transmittance.

In at least one embodiment of the present invention, a portion of the light-shielding film directly contacts the light-guiding film, and a length exists between a side of the portion farthest from the light-emitting surface and another side of the portion closest to the light-emitting surface, and the length ranges from 2 mm to 3 mm.

In at least one embodiment of the present invention, the light shielding film completely covers the top surface of the light emitting element.

In at least one embodiment of the present invention, the first light emitting surface directly contacts the light guide film.

In at least one embodiment of the present invention, there is a distance between the first light emitting surface and the light guide film, and the distance does not exceed 1 mm.

In at least one embodiment of the present invention, the light emitting element further includes at least one second light emitting surface, and the second light emitting surface does not face the light guide film and the flexible circuit substrate.

An embodiment of the present invention further provides a reflective display device, comprising any light source module as described in the above embodiments, and a reflective display panel disposed opposite to the light source module.

In the above embodiment, by designing that the width of the first light-emitting surface does not exceed four times the thickness of the light-guiding film, the light coupling efficiency is improved, the brightness of the light source module is increased, and the imaging quality of the reflective display device is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be understood from the following detailed description and the accompanying drawings. It should be noted that various features are not drawn to the standard scale in industry practice. In fact, the size of various features may be increased or decreased arbitrarily for the sake of clarity of discussion.

FIG1 is a side view of a light source module according to an embodiment of the present invention;

FIG2 is a front view of the light emitting surface of the light emitting element in the embodiment of FIG1 ;

FIG3 is a side view of a light source module according to another embodiment of the present invention;

FIG4 is a top view of the light source module in the embodiment of FIG3 ;

FIG. 5 is a schematic diagram of a reflective display device according to an embodiment of the present invention.

【Explanation of symbols】

10, 30, 50: Light source module

100: Flexible circuit board

100a, 100b: surface

102: Gap

120: Light emitting element

120a, 120b, 120c: light emitting surface

120s: Shell

120t, 140t: Top surface

121t, 121b: Edge

140: Light guide film

140i: light incident side

160:Light-shielding film

162: Block

162a, 162b: Side

164: Black light shielding layer

166: White light shielding layer

500: Display device

510: Display panel

D: Spacing

L: Length

OD1, OD2: Observation direction

T:Thickness

W: Width

DETAILED DESCRIPTION

The present invention will be described in detail with the following embodiments. It should be noted that the following description of the embodiments of the present invention is only for illustration and is not intended to exhaustively disclose all embodiments or to limit the specific embodiments of the present invention. For example, the description of "a first feature formed on a second feature" includes multiple implementations, including the first feature directly contacting the second feature, and also including additional features formed between the first feature and the second feature so that the two are not in direct contact. In addition, the same element symbols used in the drawings and the specification will represent the same or similar elements as much as possible.

Spatially relative terms, such as "lower," "below," "beneath," "above," and related terms, are used herein to simply describe the relationship of an element or feature as shown in the figures to another element or feature. These spatially relative terms cover different orientations when the device is used or operated in addition to the orientation depicted in the figures. In addition, when the element is rotatable (rotated 90 degrees or other angles), the spatially relative descriptors used herein can also be interpreted accordingly.

In the following text, in order to clearly present the technical features of this case, the dimensions (such as length, width, thickness and depth) of the elements (such as layers, films, substrates and regions, etc.) in the drawings will be enlarged in unequal proportions. Therefore, the description and explanation of the embodiments below are not limited to the dimensions and shapes presented by the elements in the drawings, but should cover the dimensions, shapes and deviations of the two caused by actual processes and/or tolerances. For example, the flat surface shown in the drawings may have rough and/or nonlinear features, and the acute angles shown in the drawings may be rounded. Therefore, the elements presented in the drawings of this case are mainly for illustration, and are not intended to accurately depict the actual shape of the elements, nor are they used to limit the scope of the patent application for this case.

Furthermore, the words "about", "approximately" or "substantially" that appear in the present case not only cover the numerical values and numerical ranges that are clearly recorded, but also cover the permissible deviation range that can be understood by a person with ordinary knowledge in the technical field to which the invention belongs, wherein the deviation range can be determined by the error generated during measurement, and this error is caused by, for example, the limitations of the measurement system or process conditions. In addition, "about" can mean within one or more standard deviations of the above numerical values, such as ±30%, ±20%, ±10% or ±5%. The words "about", "approximately" or "substantially" that appear in the present text can select an acceptable deviation range or standard deviation based on the optical properties, etching properties, mechanical properties or other properties, and not just one standard deviation can be applied to all the above optical properties, etching properties, mechanical properties and other properties.

FIG1 is a side view of a light source module 10 according to an embodiment of the present invention. Referring to FIG1 , the light source module 10 includes a flexible circuit substrate 100, a light emitting element 120, and a light guide film 140. The two sides of the flexible circuit substrate 100 respectively have a surface 100a and a surface 100b, wherein the light emitting element 120 and the light guide film 140 are both located on the flexible circuit substrate 100, and the light emitting element 120 and the light guide film 140 are both located on the same side of the flexible circuit substrate 100. For example, as shown in FIG1 , the light emitting element 120 and the light guide film 140 are both located on the surface 100a of the flexible circuit substrate 100.

In this embodiment, the flexible circuit substrate 100 may be a flexible printed circuit board (FPCB), and the light emitting element 120 may be an electroluminescent element such as a light emitting diode. The light emitting element 120 must be electrically connected to the flexible circuit substrate 100, so that the light emitting element 120 can be controlled to emit light by a control element (not shown) disposed on the flexible circuit substrate 100. In various embodiments of the present invention, the light emitting element 120 may have a cool color temperature (e.g., 6500K) or a warm color temperature (e.g., 3500K).

1 , the light guide film 140 of this embodiment has a light incident surface 140i, which is also one side of the light guide film 140, and the light emitting element 120 includes a light emitting surface 120a, wherein the light emitting surface 120a faces the light guide film 140. Thus, the light emitted from the light emitting surface 120a travels toward the light guide film 140 and is incident on the light incident surface 140i, thereby entering the light guide film 140.

FIG2 is a front view of the light emitting surface 120a of the light emitting element 120, please refer to FIG1 and FIG2, wherein FIG2 is drawn along the observation direction OD1 indicated in FIG1, viewing the light emitting surface 120a. As shown in FIG2, the light emitting surface 120a has an edge 121t and an edge 121b, wherein a width W is defined between the edge 121t farthest from the flexible circuit substrate 100 (equivalent to the upper edge of the light emitting surface 120a in FIG1) and the edge 121b closest to the flexible circuit substrate 100 (equivalent to the lower edge of the light emitting surface 120a in FIG1).

In addition, since the light emitting element 120 may be a light emitting diode, the light emitting element 120 may further include a housing 120s and a chip (not shown), wherein the housing 120s may be made of a molding compound, and the chip may generate light and emit the light from the light emitting surface 120a. In addition, the housing 120s may contain a fluorescent material to convert the wavelength of the light emitted by the chip, that is, to change the color of the aforementioned light.

It is worth mentioning that in other embodiments of the present invention, in addition to the light-emitting surface 120a, the light-emitting element 120 may also include at least one other light-emitting surface. For example, the light-emitting element 120 shown in FIG. 1 may also include a light-emitting surface 120b and three light-emitting surfaces 120c (FIG. 1 only shows one light-emitting surface 120c), and the light-emitting surface 120b and the light-emitting surface 120c do not face the light-guiding film 140 and the flexible circuit substrate 100. Specifically, the light-emitting surface 120b may be the top surface of the light-emitting element 120 in FIG. 1, and faces away from the flexible circuit substrate 100. The three light-emitting surfaces 120c may be arranged in a U-shape, wherein two light-emitting surfaces 120c are connected to the light-emitting surface 120a, and the remaining light-emitting surface 120c is opposite to the light-emitting surface 120a and faces away from the light-guiding film 140.

The light guide film 140 partially covers the flexible circuit substrate 100 and has a thickness T, wherein the thickness T may be less than or equal to 100 μm, i.e., not greater than 100 μm. In various embodiments of the present invention, the thickness T of the quadruple light guide film 140 may be greater than or equal to the width W of the light emitting surface 120 a. In other words, the width W of the light emitting surface 120 a does not exceed four times the thickness T of the light guide film 140 (i.e., 4T≧W). In this way, the central brightness of the light source module 10, i.e., the central brightness of the top surface 140 t of the light guide film 140, may reach a range of 99.4 nits to 104.1 nits, and the average brightness at the light entrance, i.e., the average brightness of the top surface 140 t close to the light entrance surface 140 i, may reach a range of 93.8 nits to 107.6 nits. In addition, the average brightness of the light source module 10 may fall between 88.5 nits and 95.0 nits.

It should be noted that, although the thickness T of the light guide film 140 in this embodiment is not greater than 100 μm, the thickness T of the light guide film 140 is not limited thereto. In other embodiments, the thickness T of the light guide film 140 may also exceed 100 μm. In addition, the material of the light guide film 140 may include polymethylmethacrylate (PMMA), polycarbonate (PC), methyl methacrylate-styrene (MS) resin or other similar polymer materials.

Please continue to refer to FIG. 1 , there is a distance D between the light emitting surface 120a and the light guide film 140. In the present embodiment, the distance D between the light emitting surface 120a and the light guide film 140 does not exceed 1 mm. However, the present invention is not limited thereto, and the distance D may be greater than 1 mm. The distance D can form a gap 102 between the light emitting surface 120a and the light guide film 140, wherein the gap 102 may contain, for example, air or other gases. It is worth mentioning that in some embodiments of the present invention, the light emitting surface 120a may also directly contact the light guide film 140, wherein no gap 102 may be formed between the light emitting surface 120a and the light guide film 140.

FIG3 is a side view of a light source module 30 according to another embodiment of the present invention. Referring to FIG3 , the difference between the light source module 30 according to the present embodiment and the light source module 10 according to the embodiment of FIG1 is that the light source module 30 further includes a light shielding film 160. The light shielding film 160 is located on the light guide film 140, wherein the light shielding film 160 and the flexible circuit substrate 100 are respectively located on opposite sides of the light guide film 140, and the light shielding film 160 is located on the top surface 140t of the light guide film 140, as shown in FIG3 .

In the embodiment shown in FIG3 , the light shielding film 160 covers the top surface 120t of the light emitting element 120, wherein the top surface 120t is the same as the light emitting surface 120b shown in FIG1 , and the light shielding film 160 completely covers the top surface 120t of the light emitting element 120. On the other hand, the light shielding film 160 only partially covers the light guide film 140, but does not completely cover the light guide film 140. Specifically, one of the blocks 162 of the light shielding film 160 covers the light guide film 140, and the block 162 can directly contact the light guide film 140.

FIG. 4 is a top view of the light source module 30. Please refer to FIG. 3 and FIG. 4, wherein FIG. 4 is drawn along the observation direction OD2 indicated in FIG. 3, while viewing the light shielding film 160. As shown in FIG. 4, the block 162 of the light shielding film 160 has two opposite side edges 162a and a side edge 162b, wherein the side edge 162a farthest from the light-emitting surface 120a (i.e., the leftmost edge of the block 162 in FIG. 3) and the side edge 162b closest to the light-emitting surface 120a (i.e., the rightmost edge of the block 162 in FIG. 3) have a length L. In some embodiments of the present invention, the length L may be between 2 mm and 3 mm. However, in other embodiments, the length L of the present invention is not limited thereto and may be any length.

3, the light shielding film 160 of this embodiment includes a black light shielding layer 164 and a white light shielding layer 166, wherein the white light shielding layer 166 is located between the black light shielding layer 164 and the light guide film 140. It is worth mentioning that for visible light, the black light shielding layer 164 of this embodiment is not light-transmissive, while the white light shielding layer 166 is light-transmissive.

In other embodiments, the number of light shielding layers in the light shielding film 160 is not limited to two layers (i.e., the black light shielding layer 164 and the white light shielding layer 166), and may be more than two layers or only one layer. In addition, the color of the light shielding layer is not limited to black and white, that is, the light shielding film 160 may include light shielding layers of other colors, such as a yellow light shielding layer or a red light shielding layer. In addition, the material of the light shielding film 160 may include a polyester film (e.g., a PET film) or other similar materials that are not completely transparent.

The black light shielding layer 164 included in the light shielding film 160 has a high light absorption rate. When part of the light emitted from the light emitting surface 120a is not incident on the light guide film 140, the light can be absorbed by the light shielding film 160 to avoid light leakage or reduce the adverse effects caused by light leakage. In addition, the provision of the light shielding film 160 can effectively prevent the light uniformity of the light guide film 140 from being affected by the scattering of light emitted from the light emitting surface 120a, so as to achieve a better light uniformity effect.

FIG5 is a schematic diagram of a reflective display device 500 according to at least one embodiment of the present invention. Referring to FIG5 , the display device 500 includes a light source module 50 and a reflective display panel 510, wherein the reflective display panel 510 is disposed relative to the light source module 50. The light source module 50 of this embodiment is substantially the same as the light source module 10 or the light source module 30 of the aforementioned embodiment. In other words, the light source module in the display device 500 may also be the light source module 10 or the light source module 30.

As shown in Fig. 5, the light source module 50 covers the reflective display panel 510, wherein the reflective display panel 510 may include, for example, an electrophoretic display panel, a cholesterol liquid crystal display panel or a similar display panel. Using the light source module in the above embodiment as a front light source can improve the display brightness of the reflective display panel 510.

In summary, when the width of the light-emitting surface in the light source module does not exceed four times the thickness of the light-guiding film, the light coupling efficiency can be improved, thereby increasing the brightness of the light source module. In addition, the light-shielding film in the light source module can also improve light leakage and improve light uniformity, thereby improving the image quality of the reflective display.

Although the embodiments of the present invention have been disclosed above, they are not intended to limit the embodiments of the present invention. Any person with ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention shall be determined by the definition of the attached claims.

Claims (11)

1. A light source module, comprising: A flexible circuit substrate; a light emitting element, located on the flexible circuit substrate; and A light guide film is located on the flexible circuit substrate, wherein the light guide film and the light emitting element are located on the same side of the flexible circuit substrate, and a first light emitting surface of the light emitting element faces the light guide film; wherein a width is defined between an edge of the first light-emitting surface that is farthest from the flexible circuit substrate and another edge of the first light-emitting surface that is closest to the flexible circuit substrate; The light guide film has a thickness, and the width of the first light emitting surface is no more than four times of the thickness. 2 . The light source module as claimed in claim 1 , wherein the thickness of the light guide film is not greater than 100 μm. 3. The light source module according to claim 1, further comprising: A light shielding film is located on the light guiding film, wherein the light shielding film and the flexible circuit substrate are respectively located on two opposite sides of the light guiding film. 4 . The light source module as claimed in claim 3 , wherein the light shielding film covers a top surface of the light emitting element. 5 . The light source module as claimed in claim 4 , wherein the light shielding film completely covers the top surface of the light emitting element. 6. The light source module as claimed in claim 4, wherein the light shielding film comprises: a black light shielding layer; and A white light shielding layer is located between the black light shielding layer and the light guiding film, and the white light shielding layer has light transmittance. 7. The light source module as described in claim 4 is characterized in that a block of the light-shielding film is directly in contact with the light-guiding film, and there is a length between a side of the block farthest from the first light-emitting surface and another side of the block closest to the first light-emitting surface, and the length is between 2 mm and 3 mm. 8 . The light source module as claimed in claim 1 , wherein the first light emitting surface directly contacts the light guide film. 9 . The light source module as claimed in claim 1 , wherein there is a distance between the first light emitting surface and the light guide film, and the distance does not exceed 1 mm. 10 . The light source module as claimed in claim 1 , wherein the light emitting element further comprises at least one second light emitting surface, and the second light emitting surface does not face the light guide film and the flexible circuit substrate. 11. A reflective display device, comprising: A light source module as claimed in any one of claims 1 to 10; and A reflective display panel is arranged opposite to the light source module.