CN102841393A - Reflective sheet and optical touch device of the reflective sheet - Google Patents

Abstract

The present invention provides a reflective sheet, which includes a substrate, a plurality of protruding structures and a plurality of reflective microstructures. The substrate has a first surface, the protruding structures are arranged on the first surface of the substrate, and the reflective microstructures are arranged on the protruding structures. The present invention also provides an optical touch device using the reflective sheet. The reflective sheet of the present invention can effectively reflect incident light at different angles, and the optical touch device of the present invention has a simple structure and is easy to assemble.

Description

Reflective sheet and optical touch device of the reflective sheet

technical field

The invention relates to an optical component and a touch device, and in particular to a reflective sheet and an optical touch device using the reflective sheet.

Background technique

Touch devices have the advantage of being easy to operate, so they have been widely used in a variety of electronic products in recent years, such as mobile phones, personal digital assistants (PDAs), digital cameras, music players, computers, satellite navigation devices , touch screen, etc. Currently common touch devices include resistive touch devices, capacitive touch devices, and optical touch devices. Among them, optical touch devices have become more and more popular due to their advantages of better durability and lower cost. be valued.

The optical touch device needs to provide light to the sensing area so that the light sensing element can sense the position of the touch point. In the prior art, reflectors or light guides are usually used to guide the light emitted by the light-emitting component into the sensing area.

FIG. 1 is a schematic top view of a conventional optical touch device using a reflective sheet. Please refer to FIG. 1 , the conventional optical touch device 100 has a sensing area 101 and includes light sensing elements 110a, 110b, light sources 120a, 120b, and reflective sheets 130a, 130b, 130c. The photo-sensing element 110b and the photo-sensing element 110a are located beside the sensing area 101 and respectively located at two ends of the first side 101a of the sensing area 101 . The light source 120a is disposed on the light sensing element 110a, and the light source 120b is disposed on the light sensing element 110b. The reflective sheet 130a is arranged next to the second side 101b of the sensing area 101, the reflective sheet 130b is arranged next to the third side 101c of the sensing area 101, and the reflective sheet 130c is arranged next to the fourth side 101d of the sensing area 101 . The light sources 120a, 120b provide light to the sensing area 101, the sensing area of the light sensing element 110a covers the reflective sheets 130b, 130c, and the sensing area of the light sensing element 110b covers the reflective sheets 130a, 130b.

During operation, the reflective sheets 130a, 130b, 130c reflect the light emitted by the light sources 120a, 120b, and the light sensing elements 110a, 110b sense the light reflected by the reflective sheets 130a, 130b, 130c. When a shading object (such as a finger or a pen) is manipulated in the sensing area 101, the shading object will cause the light sensing elements 110a, 110b to sense dark areas, and according to the dark areas sensed by the light sensing elements 110a, 110b The position of the shading object can be calculated from the position of the area.

However, in the conventional optical touch device 100 , the incident angle of the light provided by the light source 120 a in the area R1 near the connection of the reflective sheets 130 b and 130 c is relatively large, resulting in poor reflection effect. Similarly, the incident angle of the light provided by the light source 120b in the area R2 near the junction of the reflective sheets 130a and 130b is relatively large, resulting in a poor reflection effect. Therefore, the brightness of the corners of the sensing region 101 (that is, the regions R1 and R2 ) is relatively dark, which will reduce the sensing accuracy of the optical touch device 100 .

FIG. 2 is a schematic top view of another conventional optical touch display device using a reflective sheet. Please refer to FIG. 2, the existing optical touch display device 100' is similar to the optical touch display device 100, the difference is that the reflective sheet 130a' and the reflective sheet 130b' are connected by a reflective sheet 130d', and The reflective sheet 130d' faces the light source 120b'. The reflective sheet 130b' and the reflective sheet 130c' are connected by a reflective sheet 130e', and the reflective sheet 130e' faces the light source 120a'. Because the incident angle of the light incident on the reflective sheet 130d', 130e' is small, the reflective sheet 130d', 130e' can reflect the light more effectively, so as to avoid reducing the optical efficiency due to the darker brightness at the corner of the sensing area 101'. Sensing accuracy of the touch display device 100'. However, the structure of the optical touch display device 100' is relatively complicated, so the assembly steps are also relatively complicated, resulting in poor production efficiency.

Contents of the invention

The invention provides a reflective sheet, which can effectively reflect incident light from different angles.

The invention provides an optical touch device, which has a simple structure and is easy to assemble.

In order to achieve the above advantages, the present invention provides a reflective sheet. The reflective sheet includes a base, a plurality of raised structures and a plurality of reflective microstructures. The base has a first surface. The protruding structures are arranged on the first surface of the base, and the reflective microstructures are arranged on the protruding structures.

In an embodiment of the present invention, the above-mentioned reflective sheet further includes a glue strip, the glue strip is disposed on the second surface of the base, and the second surface is opposite to the first surface.

In one embodiment of the present invention, each of the above-mentioned protruding structures is a prism column, and these prism columns are parallel to each other, and the bottom surfaces of two adjacent prism columns connected to the first surface are connected to each other.

In one embodiment of the present invention, each of the above-mentioned raised structures is a triangular prism.

In an embodiment of the present invention, the apex angle of each of the above-mentioned protruding structures ranges from 90 degrees to 120 degrees.

In one embodiment of the present invention, each of the above-mentioned protruding structures is a half cylinder, these half cylinders are parallel to each other, and the bottom surfaces connected to the first surface of two adjacent half cylinders are connected to each other.

In one embodiment of the present invention, the aforementioned reflective microstructures are pyramids or glass microspheres.

In one embodiment of the present invention, the above-mentioned reflective sheet further includes a protective film covering these microstructures.

In one embodiment of the present invention, the above-mentioned protective film is a filter film.

In one embodiment of the present invention, the above-mentioned base and the protruding structures are integrally formed.

In one embodiment of the present invention, the above-mentioned base and the raised structures are made of thermoplastic polyurethane (Thermoplastic Polyurethane, TPU).

The present invention also provides an optical touch device with a sensing area, and the optical touch device includes at least one reflective sheet, at least one light source and at least one light sensing element. At least one reflective sheet is disposed beside at least one side of the sensing area. Each reflective sheet includes a base, a plurality of raised structures and a plurality of reflective microstructures. The substrate has a first surface facing the sensing area. The protruding structures are arranged on the first surface of the base, and the reflective microstructures are arranged on the protruding structures. At least one light source is arranged beside the sensing area to provide light to the sensing area. At least one light-sensing element is arranged beside the sensing area, and the sensing range of each light-sensing element covers the corresponding at least one reflective sheet.

Because the reflective sheet of the present invention has a plurality of raised structures and a plurality of reflective microstructures arranged on the raised structures, it can effectively reflect light rays of different incident angles. Since the optical touch device of the present invention uses such a reflective sheet, it can avoid the corners of the sensing area from being dimmed, so as to improve sensing accuracy. Moreover, the optical touch device of the present invention has the advantages of simple structure and easy assembly.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited below, and are described in detail as follows in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic top view of a conventional optical touch display device using a reflective sheet.

FIG. 2 is a schematic top view of another conventional optical touch display device using a reflective sheet.

FIG. 3 is a schematic top view of an optical touch device according to an embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a reflective sheet of the optical touch device shown in FIG. 3 .

FIG. 5 is a three-dimensional schematic diagram of a reflective microstructure of a reflective sheet according to another embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of a reflective sheet according to another embodiment of the present invention.

the

Detailed ways

In order to further explain the technical means and effects of the present invention to achieve the intended purpose of the invention, the following describes the reflective sheet and the optical touch device using the reflective sheet according to the present invention in combination with the accompanying drawings and preferred embodiments. Embodiments, structures, features and effects thereof are described in detail below.

FIG. 3 is a schematic top view of an optical touch device according to an embodiment of the present invention. Referring to FIG. 3 , the optical touch device 200 of this embodiment has a sensing area 201 and includes at least one reflective sheet, at least one light source disposed beside the sensing area 201 and at least one side of the sensing area 201 At least one light sensing element next to it. In this embodiment, at least one light sensing element includes, for example, light sensing elements 210 a , 210 b disposed at two ends of the side 201 a of the sensing area 201 . The light sensing elements 210a and 210b can be complementary metal oxide semiconductor (CMOS) image sensing elements, charge coupled devices (charge coupled device, CCD) or other suitable light sensing elements. In addition, the at least one light source includes, for example, a light source 220a disposed on the light sensing element 210a and a light source 220b disposed on the light sensing element 210b. The light sources 220a, 220b can be light emitting diodes, laser diodes or other suitable light sources. In addition, at least one reflective sheet includes, for example, a reflective sheet 230a disposed beside the side 201b of the sensing region 201, a reflective sheet 230b disposed beside the side 201c of the sensing region 201, and a reflective sheet 230b disposed beside the side 201d of the sensing region 201. Next to the reflective sheet 230c. . It should be noted that the present invention does not limit the number of light sensing elements, light sources, and reflective sheets. In other embodiments, the number of reflective sheets, light sources, and light sensing elements can be adjusted according to actual needs. In addition, the sensing area 201 can be located on the surface of a substrate, and the substrate can be a carrier plate (such as a glass substrate or other rigid substrate). In another embodiment, the substrate can be a display panel, that is, the optical touch device 200 can be integrated with a touch display device.

FIG. 4 is a schematic cross-sectional view of a reflective sheet of the optical touch device shown in FIG. 3 . Referring to FIG. 3 and FIG. 4 , each reflective sheet 230 a , 230 b , 230 c includes a base 232 , a plurality of protruding structures 233 and a plurality of reflective microstructures 234 . The base 232 has a first surface 232 a and a second surface 232 b, wherein the second surface 232 b is opposite to the first surface 232 a, and the first surface 232 a faces the sensing region 201 . The protruding structure 233 is disposed on the first surface 232 a of the base 232 , and the reflective microstructure 234 is disposed on the protruding structure 233 . In this embodiment, the base 232 and the protruding structure 233 are integrally formed, for example, but the invention is not limited thereto. In other embodiments, the base 232 and the protruding structure 233 can be formed separately. The material of the base 232 and the protruding structure 233 includes thermoplastic polyurethane, for example.

Each protruding structure 233 in this embodiment is, for example, a prism column. These prism columns are parallel to each other, and the bottom surfaces 233a of two adjacent prism columns connected to the first surface 232a are connected to each other, that is, between two adjacent prism columns. There is no gap between them. However, in other embodiments, the bottom surfaces 233 a of the two adjacent protruding structures 233 connected to the first surface 232 a may not be connected to each other, that is, the two adjacent protruding structures 233 are separated by a certain distance. In addition, in this embodiment, each protruding structure 233 is, for example, a triangular prism, and the range of the vertex angle θ of each protruding structure 233 is, for example, 90 degrees to 120 degrees. The width of the bottom surface of each protruding structure 233 connected to the first surface 232a is, for example, 1 mm to 2 mm, and the height H of each protruding structure 233 is, for example, about 1 mm. The protruding structures 233 can be made by embossing technology, and the reflective effect of the reflective sheets 230a, 230b, 230c can be controlled by adjusting the height H and the angle θ of the protruding structures 233 .

The aforementioned reflective microstructures 234 are, for example, glass microspheres, and the diameter of each glass microsphere is, for example, about 100 micrometers (micrometer). The glass microspheres include, for example, a bead body 234 a and a reflective film 234 b disposed between the bead body 234 a and the protruding structure 233 . The beads 234a are used to refract the light 221 provided by the light sources 220a and 220b. The reflective film 234b is, for example, a metal film (such as an aluminum film) for reflecting the light 221 . In addition, the present invention does not limit the reflective microstructures to be glass beads. For example, as shown in FIG. 6 , each reflective microstructure 234' can also be a pyramid.

In this embodiment, each reflective sheet 230a, 230b, 230c may further include a rubber strip 235 . The adhesive strip 235 is disposed on the second surface 232 b of the base 232 for supporting the base 232 . In addition, each reflective sheet 230 a , 230 b , 230 c may further include a protective film 236 covering the reflective microstructure 234 to protect the reflective microstructure 234 . For example, there is a slight gap between the protective film 236 and the reflective microstructure 234 , so that the reflective microstructure 234 can provide a good reflective effect. In one embodiment, the protective film 236 can be a filter film to filter out light outside a specific wavelength band, thereby improving the sensing accuracy of the optical touch device 200 . For example, when the light 221 provided by the light sources 220a and 220b is infrared light, the protective film 236 can allow the infrared light to pass through and filter out light outside the infrared light band.

When the optical touch device 200 of this embodiment is working, since the raised structures 233 of the reflective sheets 230a, 230b, and 230c allow the reflective microstructures 234 to face in different directions, the reflective sheets 230a, 230b, and 230c can effectively reflect different incident angles. Ray 221. Therefore, the reflective sheets 230 a , 230 b , and 230 c can also effectively reflect light rays with relatively large incident angles, so as to prevent the corners of the sensing area 201 from being dark, thereby improving the sensing accuracy of the optical touch device 200 . In addition, compared with the existing optical touch device 100 ′, the optical touch device 200 of this embodiment does not need additional reflective sheets facing the light sources 220 a and 220 b at the corners of the sensing area 201 , so the structure is relatively simple. It is beneficial to improve the assembly efficiency.

6 is a schematic cross-sectional view of a reflective sheet of an optical touch device according to another embodiment of the present invention. Please refer to FIG. 6 , the structure of the reflective sheet 330 in this embodiment is similar to that of the aforementioned reflective sheet 230 a , 230 b or 230 c , the difference being that each protruding structure 333 of the reflective sheet 330 is a semi-cylindrical. These half-cylinders are parallel to each other, and the bottom surfaces 333 a of two adjacent half-cylinders connected to the first surface 332 a of the base 332 are connected to each other. In other embodiments, the bottom surfaces 333 a of the two adjacent half cylinders connected to the first surface 332 a of the base 332 may not be connected to each other. It should be noted that the present invention does not limit the protruding structures to be prism columns or semi-cylindrical columns, and in other embodiments, the cross-sections of these protruding structures may also be wave-shaped or multiple circular arcs connected in sequence. In this embodiment, the reflective microstructures 334 are, for example, glass beads. In other embodiments, the reflective microstructures may also be pyramids. In addition, the reflective sheet 330 of this embodiment can replace the aforementioned reflective sheets 230a, 230b, 230c to provide similar functions.

To sum up, the reflective sheet of the present invention has a plurality of raised structures, so that the reflective microstructures disposed on the raised structures face in different directions, so the reflective sheet of the present invention can effectively reflect light rays of different incident angles. Because the optical touch device of the present invention uses the reflective sheet, the problem of darker brightness at the corners of the sensing area can be eliminated, so as to improve the sensing accuracy of the optical touch device. Moreover, the optical touch device of the present invention has a simple structure, so it is beneficial to improve assembly efficiency.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the technical content disclosed above to make some changes or modify them into equivalent embodiments with equivalent changes, but as long as they do not depart from the technical solution of the present invention, the Technical Essence Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims (20)

1. A reflective sheet, characterized in that it comprises a base, a plurality of raised structures and a plurality of reflective microstructures, the base has a first surface facing the sensing region, and the raised structures are configured on the base On the first surface, the reflective microstructures are arranged on the protruding structures. 2. The reflective sheeting according to claim 1, wherein the reflective sheet further comprises an adhesive strip disposed on a second surface of the base, and the second surface is opposite to the first surface . 3. The reflective sheet as claimed in claim 1, wherein each raised structure is a prism column, and the prism columns are parallel to each other, and the bottom surfaces of adjacent two prism columns connected to the first surface are mutually connected. 4. The reflective sheeting according to claim 3, wherein each raised structure is a triangular prism. 5 . The reflective sheet as claimed in claim 4 , wherein the vertex angle of each protruding structure ranges from 90° to 120°. 6. The reflective sheet as claimed in claim 1, wherein each raised structure is a half cylinder, the half cylinders are parallel to each other, and the bottom surfaces of the adjacent two half cylinders connected to the first surface are mutually connected. 7. The reflective sheet of claim 1, wherein the reflective microstructures are pyramids or glass beads. 8. The reflective sheet as claimed in claim 1, further comprising a protective film covering the microstructures. 9. The reflective sheet according to claim 8, wherein the protective film is a filter film. 10. The reflective sheet as claimed in claim 1, wherein the base and the protruding structures are integrally formed. 11. The reflective sheet as claimed in claim 10, wherein the base and the protruding structures are made of thermoplastic polyurethane. 12. An optical touch device having a sensing area, the optical touch device comprising at least one reflective sheet, at least one light source and at least one light sensing element, the at least one reflective sheet is arranged in the sensing area Next to at least one side of the sensing area, the at least one light source is arranged next to the sensing area to provide light to the sensing area, the at least one photo-sensing element is arranged next to the sensing area, and each photo-sensing element The sensing range covers at least one corresponding reflective sheet, wherein each reflective sheet includes a base, a plurality of raised structures and a plurality of reflective microstructures, the base has a first surface facing the sensing area, The protruding structures are configured on the first surface of the base, and the reflective microstructures are configured on the protruding structures. 13. The optical touch device according to claim 12, wherein each reflective sheet further comprises an adhesive strip, the adhesive strip is disposed on a second surface of the base, and the second surface is in contact with the second surface The first surface is opposite. 14. The optical touch device according to claim 12, wherein each protruding structure is a prism column, and the prism columns are parallel to each other, and two adjacent prism columns are connected to the first surface bottoms are connected to each other. 15. The optical touch device as claimed in claim 14, wherein each protruding structure is a triangular prism. 16 . The optical touch device as claimed in claim 15 , wherein the vertex angle of each protruding structure ranges from 90 degrees to 120 degrees. 17. The optical touch device according to claim 12, wherein each protruding structure is a half-cylinder, the half-cylinders are parallel to each other, and two adjacent half-cylinders are connected to the first surface bottoms are connected to each other. 18. The optical touch device according to claim 12, wherein the reflective microstructures are pyramids or glass beads. 19. The optical touch device as claimed in claim 12, wherein each reflective sheet further comprises a protective film covering the microstructures. 20. The optical touch device according to claim 19, wherein the protective film is a filter film.

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