TWI663620B - Backlight module and light emitting keyboard - Google Patents

Abstract

The invention provides a backlight module and a light-emitting keyboard. The backlight module is used to illuminate a plurality of keys. The backlight module includes a plurality of light emitting units and a light guide plate. The plurality of light-emitting units are respectively disposed below the plurality of keys. The light guide plate includes a light entrance surface, a light exit surface, and a plurality of light diffusion units. Each light diffusion unit corresponds to one of the plurality of light emitting units, and each light diffusion unit is located above the corresponding light emitting unit. Each light diffusion unit includes at least one diffusion structure, and the at least one diffusion structure is disposed on at least one of the light incident surface and the light exit surface. Each diffusion structure includes a plurality of concentrically arranged curved rings, and the plurality of curved rings have a common focus located at the center of the corresponding light emitting unit.

Description

Backlight module and illuminated keyboard

The invention relates to a backlight module and a light-emitting keyboard, in particular to a backlight module having a diffusion structure and a light-emitting keyboard using the backlight module.

The application range of the light guide plate is getting wider and wider. For example, the light guide plate technology is used in the panel, the illuminated keyboard, and the advertisement signboard. As the application level becomes more and more extensive, under the premise of increasing demand, the industry is also constantly improving the optical effect of the light guide plate in order to improve the user experience in different fields.

In more and more light guide plate application fields, there is a need for controlling the light exit angle and the light exit position on the light exit surface of the light guide plate. For example, some light-emitting keyboards are difficult to control the light emitting direction due to the light guide plate therein, and it is easy to cause light leakage in the gap between the edges of the keys, which reduces the aesthetics of the keyboard and wastes light sources.

The conventional direct-type light source light guide plate generally contains diffusion particles for scattering light, so that the incident light can be uniformly emitted from the light emitting surface. However, it is difficult to accurately control the position and density of diffuse particles in the light guide plate, and the light will have different exit directions when the light enters the diffuse particles at different angles. Therefore, it is difficult for the conventional light guide plate to control the direction and position of the outgoing light. . For this reason, the prior art light guide plate is still insufficient and has room for improvement.

Following the above, the technical problem to be solved by the present invention lies in The invention provides a backlight module and a light-emitting keyboard using the backlight module. The light guide plate in the backlight module has a light diffusing unit that can increase the light diffusivity and increase the light exit angle, thereby improving the lighting effect of the light-emitting keyboard and saving light sources.

One of the technical solutions adopted in the embodiments of the present invention is to provide a backlight module for illuminating a plurality of keys. The backlight module includes a plurality of light emitting units and a light guide plate. The plurality of light-emitting units are respectively disposed below the plurality of keys. The light guide plate is disposed above the plurality of light emitting units. The light guide plate includes a light entrance surface, a light exit surface, and a plurality of light diffusion units. Each light diffusion unit corresponds to one of a plurality of light emitting units, and each light diffusion unit is located above the corresponding light emitting unit. Each light diffusion unit includes at least one diffusion structure, and the at least one diffusion structure is disposed on at least one of the light incident surface and the light exit surface. Each diffusion structure includes a plurality of concentrically arranged curved rings, and the plurality of curved rings have a common focus. The common focus is located at the center of the corresponding light emitting unit.

Another technical solution adopted in the embodiment of the present invention is to provide a backlight module for illuminating a plurality of keys. The backlight module includes a plurality of light emitting units and a light guide plate. The plurality of light-emitting units are respectively disposed below the plurality of keys. The light guide plate is disposed above the plurality of light emitting units. The light guide plate includes a light entrance surface, a light exit surface, and a plurality of light diffusion units. Each light diffusion unit corresponds to one of a plurality of light emitting units, and each light diffusion unit is located above the corresponding light emitting unit. Each light diffusion unit includes at least one diffusion structure, and the at least one diffusion structure is disposed on at least one of the light incident surface and the light exit surface. Each diffusion structure includes a plurality of concentrically arranged curved rings, each curved ring has a first surface and a second surface, each first surface is a curved surface, and each first surface is selected from a spherical curved surface and a non-circular curved surface. A group of spherical curved surfaces, where each first surface has a common focal point, each first surface faces away from the focal point, and each second surface is connected between two adjacent first surfaces.

Another technical solution adopted in the embodiment of the present invention is to provide a A backlight module for illuminating a plurality of keys. The backlight module includes a plurality of light emitting units and a light guide plate. A plurality of light-emitting units are respectively disposed below the plurality of keys. The light guide plate is disposed above the plurality of light emitting units. The light guide plate includes a light transmitting plate and a plurality of light diffusion units. The light-transmitting plate is made of a first material. Each light diffusion unit corresponds to one of the plurality of light emitting units, and each light diffusion unit is located above the corresponding light emitting unit. Each light diffusion unit includes at least one diffusion structure. The diffusion structure is composed of a second material. The light diffusion rate of the second material is greater than the light diffusion rate of the first material. Each light diffusion unit is formed by a second injection molding step. In light-transmitting sheet.

Another technical solution adopted by the embodiment of the present invention is to provide a light-emitting keyboard, which includes: a bottom plate, a plurality of keys, and a backlight module as described above, wherein the plurality of keys are disposed on the bottom plate and a plurality of light-emitting units. The light guide plate is disposed under the bottom plate and corresponds to a plurality of keys, respectively. The light guide plate is disposed between the plurality of light emitting units and the plurality of keys.

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and description, and are not intended to limit the present invention.

Z‧‧‧ backlight module

1‧‧‧light guide

101‧‧‧Into the light surface

102‧‧‧light surface

11‧‧‧light diffusion unit

12‧‧‧Translucent sheet

111‧‧‧ diffusion structure

112‧‧‧ auxiliary astigmatism structure

R‧‧‧ curved ring

S1‧‧‧First surface

S2‧‧‧Second surface

F‧‧‧ Focus

A‧‧‧ Optical axis

2‧‧‧light-emitting unit

C‧‧‧light unit center

L‧‧‧light

3‧‧‧ substrate

U‧‧‧ Illuminated Keyboard

3‧‧‧ button

30‧‧‧Keycap

31‧‧‧actuating assembly

4‧‧‧ floor

41‧‧‧support film

42‧‧‧ conductive film

421‧‧‧on point

H‧‧‧ opening

5‧‧‧ film layer

FIG. 1 is a schematic diagram of a backlight module according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged schematic diagram of FIG. 1.

FIG. 3 is a partially enlarged schematic diagram of a backlight module according to a modified embodiment of the first embodiment of the present invention.

FIG. 4 is a partially enlarged schematic view of a backlight module according to another modified embodiment of the first embodiment of the present invention.

FIG. 5 is a partially enlarged schematic diagram of a backlight module according to another modified embodiment of the first embodiment of the present invention.

6 is a schematic perspective view of a light-emitting keyboard according to a first embodiment of the present invention.

FIG. 7 is a cross-sectional side view of one of the keys in the illuminated keyboard according to the first embodiment of the present invention.

FIG. 8 is a schematic top view of the button shown in FIG. 7.

FIG. 9 is a partially enlarged schematic diagram of a backlight module according to a second embodiment of the present invention.

FIG. 10 is a partially enlarged schematic diagram of a backlight module according to a modified embodiment of the second embodiment of the present invention.

11 is a partial cross-sectional side view of a light-emitting keyboard according to a second embodiment of the present invention.

The embodiments of the backlight module and the light-emitting keyboard disclosed in the present invention will be described below in conjunction with specific embodiments in conjunction with FIGS. 1 to 11. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. However, the content disclosed below is not intended to limit the protection scope of the present invention, and those skilled in the art can implement the present invention in different embodiments based on different viewpoints and applications without departing from the principle of the concept of the present invention. In addition, it should be stated in advance that the drawings of the present invention are only schematic illustrations, and are not depicted in actual dimensions. In addition, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are mainly used to distinguish components.

First embodiment

Referring to FIG. 1, a first embodiment of the present invention provides a backlight module Z, which includes a plurality of light emitting units 2 and a light guide plate 1. The light guide plate 1 is disposed above the plurality of light emitting units 2 and has a light incident surface 101, a light emitting surface 102, and a plurality of light diffusion units 11. Specifically, a plurality of light-emitting units 2 are disposed on a substrate 3, and each light-diffusion unit 11 corresponds to one of the plurality of light-emitting units 2, and as shown in FIG. 1, each light-diffusion unit 11 is located on a corresponding light-emitting unit. Above unit 2.

In this embodiment, the material of the light guide plate 1 is preferably polycarbonate (PC), acrylic (PMMA), or glass. The light emitting unit 2 may be a light emitting diode. However, the above is merely an example, and the present invention is not limited to the type of material of the light guide plate 1 or the selection of the light emitting unit 2.

Please refer to FIG. 1 and FIG. 2 for cooperation. Further, each light diffusion unit 11 includes at least one diffusion structure 111, and each diffusion structure 111 is disposed on at least one of the light incident surface 101 and the light exit surface 102. That is, the diffusion structure 111 may be disposed on the light incident surface 101 and the light exit surface 102, or the light incident surface 101 and the light exit surface 102 are both provided with the diffusion structure 111. As shown in FIG. 2, the diffusion structure 111 includes a plurality of concentrically arranged curved surface rings R, and the plurality of curved surface rings R have a common focal point F, which is located at the center C of the corresponding light emitting unit 2. Furthermore, as shown in FIG. 2, in this embodiment, the light emitting unit 2 is symmetrical to the optical axis A of the curved ring R.

Specifically, in this embodiment, a plurality of curved surface rings R form a Fresnel lens, and the center of the Fresnel lens is the common focus F of each curved surface ring R. As shown in FIG. 2, each curved surface ring R has a first surface S1 and a second surface S2. All the first surfaces S1 of each diffusion structure 111 are formed by a common spherical curved surface, and each second surface S2 is connected to an adjacent surface. Between the two first surfaces S1 such that all the first surfaces S1 of each of the diffusion structures 111 have a common focus F. Specifically, each first surface S1 is a continuous segment divided by a common spherical surface, and as shown in FIG. 2, in this embodiment, the common focus F coincides with the center of the light emitting unit 2. As a result, the astigmatism effect when the light L emitted from the light emitting unit 2 passes through the diffusion structure 111 is similar to the astigmatism effect caused by setting a light source at the focal point of a spherical concave lens. Compared with the conventional light guide plate 1, the astigmatism effect and light diffusion can be improved. Uniformity. However, the present invention is not limited to the above; among other things, the center of the light-emitting unit 2 can be staggered from the common focus F, and the incident light beam can also be diffused by each of the first curved surfaces S1 of the diffusion structure 111, so that the incident light is larger. The light exits the light guide plate 1.

The principle of the Fresnel lens is to divide the lens into a plurality of concentric circles and remove the internal materials to retain only the surface structure part, so as to achieve the same focusing or astigmatic effect as the lens Results, while saving the use of lens materials. In this embodiment, a Fresnel lens formed by a spherical concave lens is integrated on the light emitting surface 102 of the light guide plate 1, and the center of the Fresnel lens (that is, the common focus F of the curved ring R) is set at the center C of the light emitting unit 2. As a result, the light guide plate 1 has astigmatism capability like a spherical concave lens.

Further, the present invention does not limit that all the first curved surfaces S1 of the same diffusion structure 111 are formed by a common spherical curved surface. In a variant embodiment, as shown in FIG. 3, the first surface S1 of the diffusion structure 111 may also be formed by a Formed by a common aspheric surface. Aspheric lenses have a higher ability to control the direction of light than spherical lenses. This is because the light emitting surface of the spherical lens must be spherical. Due to this limitation, the parameters that can be adjusted according to the requirements of the spherical lens are limited; compared to the spherical lens, the aspheric lens can have different light emitting curved surface designs according to application requirements. For example, if the aspheric lens is designed to have a small radius of curvature near the optical axis and a large curvature away from the optical axis, the amount of light near the optical axis can be increased. Therefore, in the backlight module Z of this embodiment as shown in FIG. 3, the diffusion structure 111 formed by the aspherical lens can control the light diffusion direction.

Please refer to FIG. 4 and FIG. 5. In other variations of this embodiment, the light incident surface 101 and the light exit surface of the light guide plate 1 are both provided with a diffusion structure 111. FIG. 4 illustrates an embodiment in which a spherical Fresnel lens is provided on both the light incident surface 101 and the light exit surface 102. The first surface S1 of the diffusion structure 111 provided on the light incident surface 101 is a first spherical surface having a first curved surface radius. The curved surface is formed. The diffusion structure 111 provided on the light emitting surface 102 is formed by a first spherical curved surface having a first curved radius. As can be seen from FIG. 4, the first spherical curved surface is different from the second spherical curved surface, that is, the first curved surface. The radius is different from the second surface radius.

FIG. 5 illustrates an embodiment in which an aspheric Fresnel lens is provided on both the light incident surface 101 and the light emitting surface 102. The first surface S1 of the diffusion structure 111 provided on the light incident surface 101 is formed by a first aspheric curved surface. The diffusion structure 111 on the light emitting surface 102 is formed by a second aspheric curved surface, and it can be seen from FIG. 4 that the first aspheric curved surface is different from the second aspheric curved surface. As can be seen from Figure 5, The first aspheric surface is different from the second aspheric surface.

By setting Fresnel lenses formed by spherical surfaces with different curvature radii on the light incident surface 101 and the light output surface 102 of the light guide plate 1, the required light emission position and direction can be obtained by matching the curvature radii. Similarly, by setting different Fresnel lenses formed on the light incident surface 101 and the light emitting surface 102 of the light guide plate 1 with different aspheric curved surfaces, the desired light emitting position and direction can be achieved by the curved surface design.

In addition, it should be noted that, in this embodiment, the pitch of the curved ring R is not limited to that shown in the drawings. The pitch, height, and width of the curved ring R can be designed according to actual needs. Specifically, the selection of the pitch, height, and width of the curved ring R can be matched with the curvature radius or curved shape of the spherical or aspherical Fresnel lens to achieve a specific exit of the incident light on the light-emitting surface 102 of the light guide plate 1. Position and shooting angle.

It is worth mentioning that on the premise that the distance between the light-emitting unit 2 and the light guide plate 1 is fixed, the curvature radius of the first surface S1 formed by the spherical curved surface can be obtained according to the imaging formula of the spherical lens:

Similarly, the curvature radius of the first surface S1 formed by the aspheric surface can be obtained according to the aspheric lens imaging formula:

In contrast, if the curvature radius of the first surface S1 has a better predetermined value according to the actual application requirements, the distance between the light-emitting unit 2 and the center of the diffusion structure 111 can be in accordance with the above-mentioned formula according to the above formula. .

It should be noted that, in this embodiment, each first surface S1 of the diffusion structure 111 is a segmented surface formed by dividing a common spherical surface or a common aspheric surface. However, this embodiment The invention is not limited to this. For example, in other embodiments, each first surface S1 may be a segment of a spherical curved surface, and the spherical curved surfaces forming each first surface S1 are different from each other. In these embodiments, each curved ring R has a respective focal point, and the diffusion structure 111 does not have a common focal point.

In addition, in this embodiment, the diffusion structure 111 is formed on the light guide plate 1 through a hot pressing process. Specifically, it can be processed on rollers, steel plates or nickel plates by computer numerical control (CNC) technology, laser engraving or thermal transfer technology, and then transferred to the roller-to-roll method. On the light guide plate 1. However, the above is merely an example, and the present invention does not limit the manner in which the diffusion structure 111 is formed on the light guide plate 1.

Please refer to FIG. 6 and FIG. 7, this embodiment further provides a light-emitting keyboard U, which includes a bottom plate 4, a plurality of keys 3, and the backlight module Z as described above. FIG. 7 shows a cross-sectional side view of one of the keys 3 in FIG. 6, wherein the light-emitting unit 2 is disposed below the bottom plate 4 and corresponds to a key 3. The key 3 has a light-transmissive keycap 30 for the light generated by the light-emitting unit 2. L passed. The light emitting unit 2 is disposed on the substrate 3. In this embodiment, a thin film layer 5 is provided between the substrate 3 and the light guide plate 1. As shown in FIG. 7, the thin film layer 5 has a through hole capable of accommodating the light emitting unit, and the thickness of the thin film layer 5 can be calculated according to actual needs, so that the interval between the light emitting unit 2 and the diffusion structure 111 is the first surface of the diffusion structure 111. Focal length of S1.

Please refer to FIG. 7 and FIG. 8. FIG. 8 is a top view of the button 3 shown in FIG. As shown in FIG. 8, in this embodiment, the bottom plate 4 has an opening H, and the position of the opening H corresponds to the light emitting unit 2 and the diffusion structure 111 so that the light L generated by the light emitting unit 2 passes through the diffusion structure 111 and the opening H. The light-emitting keyboard U is emitted from the light-transmitting keycap 30.

Please continue to refer to FIGS. 7 and 8. Further, the button 3 further includes an actuating component 31, and the bottom plate 4 includes a supporting film layer 41 and a conducting film layer 42, wherein the conducting film layer 42 has a conducting point 421. When the button 3 is pressed down to a trigger position, the actuating component 31 will trigger the conducting point 421 to make the circuit in the conducting film layer 42 conduct and output the key signal. As shown in FIG. 8, in this embodiment, the expansion The diffusion structure 111 is disposed on both sides of the conducting point 421 so that the light emitted by the light emitting units 2 corresponding to the diffusion structures 111 can be evenly diffused to the four corners of the keycap 30 to illuminate the four corners shown on the keycap 30. Characters. A conventional light-emitting keyboard usually has a light-emitting unit under the keycap corresponding to the number of characters on the keycap. For example, if a keycap displays four characters, four light-emitting units are required to correspond to the four characters. Position so that each character glows evenly. Compared with the conventional light-emitting keyboard, this embodiment uses the backlight module Z as described above, and the diffusion structure 111 is arranged on both sides of the conduction point 421, so that only two light-emitting units 2 are needed to make the light L The diffusion to the four corners of the keycap 30 saves the amount of the light-emitting unit 2 and the power consumption required by the light-emitting unit 2.

Through the above-mentioned technical means, an embodiment of the present invention provides a backlight module Z and a light-emitting keyboard U. A diffusion structure 111 formed by a Fresnel lens is integrated on the light incident surface 101 and / or the light exit surface of the light guide plate 1 of the backlight module Z. 102, and the light-emitting unit 2 corresponds to the diffusion structure 111, and the center of the light-emitting unit 2 corresponds to the focal point F of the Fresnel lens of the diffusion structure 111, whereby the light-diffusing ability of the light guide plate can be improved by using the astigmatic effect of the Fresnel lens. In addition, by adjusting the curved surface ring R of the diffusion structure 111, such as adjusting the pitch and the radius of curvature of the light incident surface 101 and the light emitting surface 102, the specific light emitting direction and light emitting position of the light L on the light emitting surface 102 can be achieved.

Second embodiment

9 to 11 illustrate a backlight module and a light-emitting keyboard provided by a second embodiment of the present invention. In this embodiment, components corresponding to those in the first embodiment have the same reference numerals, and parts having the same structure and functions as the components are not described here. The differences between this embodiment and the first embodiment are described below. Supplied backlight module and illuminated keyboard.

The main difference between this embodiment and the first embodiment is that the light guide plate 1 includes a plurality of light diffusion units 11 and a light transmitting plate 12. Each light diffusion unit 11 corresponds to one of the light emitting units 2, and as shown in FIG. 9, the light diffusion unit 11 is located above the corresponding light emitting unit 2. In this embodiment, the light-transmitting plate is made of a first material, and the light diffusion unit 11 is made of a second material. Formed in the light-transmitting plate 12 through a secondary injection molding step, wherein the light diffusivity of the second material is greater than that of the first material.

In detail, in this embodiment, the light diffusing unit 11 is a light-transmitting material mixed with high-concentration diffusion particles; however, the present invention is not limited thereto, and in other modified embodiments, for example, it may have an internal scattering structure. Light-transmitting material. In addition, as shown in FIG. 9, in this embodiment, the light diffusion unit 11 penetrates the light incident surface 101 and the light exit surface 102 of the light guide plate 1. As a result, the light diffusing unit 11 has a larger astigmatism effect than the portion of the light-transmitting plate 12, which can diffuse the light L generated by the light emitting unit 2 directly below the light diffusing unit 11 and emit it at a large light exit angle. Glossy surface 102.

Since the conventional light guide plate is doped with diffusion particles in a light-transmitting material, the local concentration of which is difficult to accurately control. Compared with the conventional light guide plate, the light guide plate 1 of this embodiment is formed by secondary injection. Forming a light diffusion unit 11 doped with high-concentration diffusion particles in the light guide plate 1 can make the light guide plate 1 of this embodiment have a better light diffusion effect.

Further, referring to FIG. 10, in a modified embodiment, the light-transmitting plate 12 has an auxiliary light-scattering structure 112 at the outer periphery of each light-diffusing unit 11, wherein the auxiliary light-scattering structure 112 may be disposed at the entrance of the light guide plate 1. At least one of the light surface and the light emitting surface 102, and the auxiliary astigmatism structure may be specifically implemented by a V-cut structure, a spherical Fresnel lens, or an aspheric Fresnel lens. In FIG. 10, the auxiliary astigmatism structure 112 is an example of a spherical Fresnel lens provided on the light emitting surface 102. However, the present invention is not limited thereto.

Please refer to FIG. 11, a second embodiment of the present invention further provides a light-emitting keyboard using the backlight module provided in this embodiment, wherein FIG. 11 shows a partially enlarged side view of the light-emitting keyboard. As shown in FIG. 11, the light diffusing unit 11 corresponding to the button 3 is implemented by a second material doped with high-concentration diffusion particles. In addition, this embodiment is different from the first embodiment in that, in the first embodiment, the light guide plate 1 is located below the bottom plate 4, and in this embodiment, the light guide plate 1 is located above the bottom plate 4. Specifically, the present invention does not limit the relative position between the light guide plate 1 and the bottom plate 4, as long as the The light unit 2 corresponds to the light diffusion unit 11 respectively, and the light diffusion unit 11 may be located above the light emitting unit 2.

To sum up, the backlight module and the light-emitting keyboard using the backlight module provided by the embodiments of the present invention use "each diffusion structure includes a plurality of concentrically arranged curved rings" and "the plurality of curved rings have a common The technical solution of "focus" enables the backlight module and the light-emitting keyboard of the embodiment of the present invention to have a better light diffusion effect than the backlight module and the light-emitting keyboard of the prior art.

Further, in the embodiment of the present invention, by overlapping the common focal point F of the light-emitting unit 2 and the curved ring R, or using a light Fresnel lens or non-spherical lens with different curvatures on the light incident surface 101 and light exit surface 102 of the light guide plate 1 The diffusion structure 111 formed by the spherical Fresnel lens can further improve the light diffusion effect of the backlight module Z and the illuminated keyboard U. In addition, by adjusting parameters such as the pitch and height of the curved ring R, the backlight module and the light-emitting keyboard of the embodiment of the present invention can also control the light emitting direction and light emitting position.

The content disclosed above is only the preferred and feasible embodiment of the present invention, and therefore does not limit the scope of patent application of the present invention. Therefore, any equivalent technical changes made using the description and drawings of the present invention fall into the application of the present invention. Within the scope of the patent.

Claims (9)

A backlight module for illuminating a plurality of keys, the backlight module includes: a plurality of light-emitting units, each of which is correspondingly disposed below the plurality of keys; and a light guide plate, which is disposed above the plurality of light-emitting units. The light guide plate includes: a light entrance surface; a light exit surface; and a plurality of light diffusion units, each of which corresponds to one of the plurality of light emitting units, and each of the light diffusion units is located in a corresponding Above the light emitting unit; wherein each of the light diffusion units includes at least one diffusion structure, the at least one diffusion structure is disposed on at least one of the light incident surface and the light exit surface; wherein each of the diffusion structures includes a plurality of Concentric surface rings, and the plurality of surface rings have a common focus. The backlight module according to claim 1, wherein each of the diffusion structures is a Fresnel lens, and the center of the Fresnel lens is a common focus of the plurality of curved rings. The backlight module according to claim 1, wherein the common focus is located at a center of the corresponding light emitting unit. A backlight module for illuminating a plurality of keys, the backlight module includes: a plurality of light-emitting units, each of which is correspondingly disposed below the plurality of keys; and a light guide plate, which is disposed above the plurality of light-emitting units. The light guide plate includes: a light entrance surface; a light exit surface; and a plurality of light diffusion units, each of which corresponds to one of the plurality of light emitting units, and each of the light diffusion units is located in the corresponding light emitting unit. Above; wherein each of the light diffusion units includes at least one diffusion structure, the at least one diffusion structure is disposed on at least one of the light incident surface and the light exit surface; wherein each of the diffusion structures includes a plurality of concentric settings Each curved surface ring has a first surface and a second surface, each of the first surfaces is a curved surface, and each of the first surfaces is selected from the group consisting of a spherical curved surface and an aspherical curved surface In the group, each curved surface ring has a focal point, and the first surface of each curved surface ring faces away from the focal point, and each of the second surfaces is connected between two adjacent first surfaces. The backlight module according to claim 4, wherein each of the light diffusion units has two of the diffusion structures, respectively disposed on the light incident surface and the light exit surface of the light guide plate, and the light incident surface is disposed on the light incident surface. Each of the first surfaces in the diffusion structure is formed by a first spherical curved surface and has a first radius of curvature, and each of the first surfaces in the diffusion structure provided on the light emitting surface is formed of a second spherical curved surface. And has a second radius of curvature, wherein the first radius of curvature is not equal to the second radius of curvature. The backlight module according to claim 4, wherein each of the light diffusion units has two of the diffusion structures, respectively disposed on the light incident surface and the light exit surface of the light guide plate, and the light incident surface is disposed on the light incident surface. Each of the first surfaces in the diffusion structure is formed by a first aspherical curved surface, and each of the first surfaces in the diffusion structure provided on the light emitting surface is formed by a second aspherical curved surface, wherein the first An aspheric surface is different from the second aspheric surface. A light-emitting keyboard includes: a bottom plate; a plurality of keys disposed on the bottom plate; and the backlight module according to any one of claims 1 to 6, wherein the plurality of light-emitting units are disposed under the bottom plate. And each corresponding to a plurality of keys, the light guide plate is disposed between the plurality of light emitting units and the plurality of keys. The illuminated keyboard according to claim 7, wherein the light guide plate is disposed on the bottom plate. The illuminated keyboard according to claim 7, wherein the light guide plate is disposed under the base plate.