Backlight module

Abstract

A backlight module includes a circuit board, a light shield, and a light guide plate. The circuit board has a first light-emitting unit and a second light-emitting unit. The light shield is disposed above the circuit board and has a shielding area. The light guide plate is disposed between the circuit board and the light shield and includes a first single-key light-guiding area and a second single-key light-guiding area. The first single-key light-guiding area has a first through-hole to accommodate the first light-emitting unit. The second single-key light-guiding area has a second through-hole to accommodate the second light-emitting unit. The distance between the geometric center of the first single-key light-guiding area and the geometric center of the light guide plate is greater than the distance between the geometric center of the second single-key light-guiding area and the geometric center of the light guide plate. The current flowing through the first light-emitting unit is greater than the current flowing through the second light-emitting unit. This improves the problem of uneven light energy or reduced light efficiency in the first light-emitting unit caused by the expansion and contraction of the light guide plate and the circuit board.

Description

Technical Field

[0001] This disclosure relates to a keyboard device, and more particularly to a backlight module used in a keyboard device. Background Technology

[0002] Traditional keyboards often have a rather monotonous and dull appearance, so computer peripheral manufacturers have developed backlit keyboards with excellent visual effects. Backlit keyboards have a backlight module. The backlight module used in traditional keyboards consists of two main components, from top to bottom: a light-shielding layer and a light strip.

[0003] While traditional keyboard backlight modules are simple in design, they no longer meet the market's demand for thinner designs. With the evolution of LED technology, some keyboard backlight modules use smaller light-emitting elements paired with light guide plates to achieve thinner designs. The most direct way to effectively improve brightness is to shorten the distance between the light guide plate and the light-emitting element. However, when the light-emitting module expands and contracts due to temperature changes, the relative position between the light-emitting element and the light guide plate may shift, especially in areas far from the geometric center of the light guide plate (e.g., on the sides of the keyboard). This shift can lead to uneven light energy distribution or reduced luminous efficiency, and may also cause the light guide plate to touch the light-emitting element, resulting in the colloid of the light-emitting element cracking or detaching.

[0004] Therefore, how to propose a backlight module that can solve the above problems is one of the issues that the industry is currently eager to invest research and development resources to address. Summary of the Invention

[0005] In view of this, one purpose of this disclosure is to propose a backlight module that can solve the above problems.

[0006] To achieve the above objectives, according to one embodiment of this disclosure, a backlight module includes a circuit board, a light shield, and a light guide plate. The circuit board has a first light-emitting unit and a second light-emitting unit. The light shield is disposed above the circuit board and has a shielding area. The light guide plate is disposed between the circuit board and the light shield and includes a first single-key light-guiding area and a second single-key light-guiding area. The first single-key light-guiding area has a first through-hole to accommodate the first light-emitting unit. The second single-key light-guiding area has a second through-hole to accommodate the second light-emitting unit. The distance between the geometric center of the first single-key light-guiding area and the geometric center of the light guide plate is greater than the distance between the geometric center of the second single-key light-guiding area and the geometric center of the light guide plate. The current flowing through the first light-emitting unit is greater than the current flowing through the second light-emitting unit.

[0007] In one or more embodiments disclosed herein, the area of ​​the first through hole is larger than the area of ​​the second through hole.

[0008] In one or more embodiments disclosed herein, the light guide plate further includes an opaque area. The opaque area has a first expansion / contraction hole corresponding to the shielding area.

[0009] In one or more embodiments disclosed herein, the area of ​​the first expansion / contraction hole is greater than the area of ​​the first through hole or the area of ​​the second through hole.

[0010] In one or more embodiments disclosed herein, the backlight module further includes a reflective layer. The reflective layer is disposed between the light guide plate and the circuit board. A light-shielding plate covers the upper end of the first expansion hole. The reflective layer covers the lower end of the first expansion hole.

[0011] In one or more embodiments disclosed herein, the opaque area further has a second expansion orifice corresponding to the shielding area. The distance between the geometric center of the first expansion orifice and the geometric center of the light guide plate is less than the distance between the geometric center of the second expansion orifice and the geometric center of the light guide plate, and the area of ​​the first expansion orifice is greater than the area of ​​the second expansion orifice.

[0012] In one or more embodiments disclosed herein, the circuit board has a third expansion hole corresponding to the shielding area. The third expansion hole does not overlap or partially overlaps with the first or second expansion hole in its vertical position.

[0013] In one or more embodiments disclosed herein, the opaque area further comprises a second expansion orifice corresponding to the shielding area. The geometric centers of the first and second expansion orifices are respectively equidistant from the geometric center of the light guide plate. The distance between the geometric center of the first expansion orifice and the first short side of the light guide plate is equal to the distance between the geometric center of the second expansion orifice and the second short side of the light guide plate. The distance between the geometric center of the first expansion orifice and the first long side of the light guide plate is equal to the distance between the geometric center of the second expansion orifice and the second long side of the light guide plate.

[0014] In one or more embodiments disclosed herein, a first expansion orifice is located between a first light-emitting unit and a second light-emitting unit, and is configured to block optical crosstalk between the first light-emitting unit and the second light-emitting unit.

[0015] In one or more embodiments disclosed herein, one of the light-shielding plate and the circuit board is bonded to the light guide plate via a first connector.

[0016] In one or more embodiments disclosed herein, the light-shielding plate and another of the circuit boards are bonded to the light guide plate via a second bonding member.

[0017] In one or more embodiments disclosed herein, the vertical positions of the first connector and the second connector corresponding to the shielding area do not overlap or partially overlap.

[0018] In summary, in the backlight module disclosed herein, by making the current flowing through the first light-emitting unit, which is farther from the geometric center of the light guide plate, greater than the current flowing through the second light-emitting unit, which is closer to the geometric center of the light guide plate, the problem of uneven light energy or degraded light efficiency caused by the expansion and contraction of the light guide plate and the circuit board in the first light-emitting unit can be improved. By making the area of ​​the first through-hole in the light guide plate used to accommodate the first light-emitting unit larger than the area of ​​the second through-hole used to accommodate the second light-emitting unit, the problem of the light guide plate colliding with the first light-emitting unit due to expansion and contraction can be effectively avoided. By providing expansion and contraction holes in the opaque area of ​​the light guide plate, the amount of expansion and contraction of the light guide plate during temperature changes can be effectively reduced. By covering the upper and lower ends of the expansion and contraction holes with a light-shielding plate and a reflective layer, respectively, light leakage at the expansion and contraction holes can be avoided. By making the area of ​​the expansion and contraction holes farther from the geometric center of the light guide plate smaller, a balance can be achieved between the amount of expansion and contraction and the structural strength of the light guide plate. By incorporating expansion and contraction holes on the circuit board, the expansion and contraction of the circuit board during temperature changes can be effectively reduced. These holes also serve as venting holes for air between the light guide plate and the circuit board. By bonding the connectors between the light shield and the light guide plate, and / or between the circuit board and the light guide plate, at least one of the light shield and the circuit board can have substantially the same or similar expansion and contraction as the light guide plate, further ensuring that the light guide plate will not collide with the first light-emitting unit. By misaligning the connectors bonded between the light shield and the light guide plate with those bonded between the circuit board and the light guide plate, the overall thickness of the backlight module can be prevented from becoming excessive.

[0019] The above description is only used to illustrate the problem to be solved by this disclosure, the technical means to solve the problem, and the effects produced, etc. The specific details of this disclosure will be described in detail in the following implementation method and related drawings. Attached Figure Description

[0020] To make the above and other objects, features, advantages and embodiments disclosed herein more apparent and understandable, the accompanying drawings are described below:

[0021] Figure 1 To illustrate a top view of a keyboard device according to an embodiment of this disclosure;

[0022] Figure 2 For illustration Figure 1 A partial cross-sectional view of the keyboard device in the diagram;

[0023] Figure 3 For illustration Figure 1 A partial top view of the light guide plate in the image;

[0024] Figure 4 For illustration Figure 1 Another partial cross-sectional view of the keyboard device in the diagram;

[0025] Figure 5A partial cross-sectional view of a keyboard device according to another embodiment of this disclosure is provided;

[0026] Figure 6 For illustration Figure 5 A partial top view of the keyboard device in the image;

[0027] Figure 7 For illustration Figure 1 Another partial cross-sectional view of the keyboard device in the diagram;

[0028] Figure 8 For illustration Figure 1 Another top view of the keyboard device in the image;

[0029] Figure 9 For illustration Figure 8 A partial top view of the keyboard device.

[0030] [Symbol Explanation]

[0031] 100: Keyboard device

[0032] 110: Base Plate

[0033] 120, 120a, 120b: Button assembly

[0034] 130: Bracket

[0035] 200: Backlight Module

[0036] 210: Circuit board

[0037] 211: First light-emitting unit

[0038] 212: Second light-emitting unit

[0039] 220:Visor

[0040] 221: Shelter Zone

[0041] 230: Light guide plate

[0042] 231: First single-key light guide area

[0043] 231a: First through hole

[0044] 232: Second single-bond light guide area

[0045] 232a: Second through hole

[0046] 233: Opaque area

[0047] 213, 233a, 233a1, 233a2, 233a3, 233a4: Expansion / Contraction Holes; 233a11, 233a12, 233a13, 233a14, 233a21, 233a22, 233a23, 233a24: Extensions; 240: Reflective Layer

[0048] 250: First mating part

[0049] 260: Second mating component

[0050] C00, C01, C02, C03, C04, C05, C06, C11, C12, C13, C14, C21, C22: Geometric center; Dx, Dy: Horizontal direction

[0051] Dz: Vertical direction

[0052] E1: First short side

[0053] E2: Second shorter side

[0054] E3: First long side

[0055] E4: Second longest side

[0056] L1, L2, L3, L4: Distance Detailed Implementation

[0057] The following describes several embodiments of this disclosure with reference to the accompanying drawings. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit this disclosure. That is, in some embodiments of this disclosure, these practical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and elements will be shown in the drawings in a simple schematic manner.

[0058] Please refer to Figure 1 This is a top view illustrating a keyboard device 100 according to an embodiment of this disclosure. Figure 1 As shown, in this embodiment, the keyboard device 100 includes a base plate 110, a plurality of key assemblies 120, and a backlight module 200 (labeled as...). Figure 2The key assembly 120 is disposed above the base plate 110 and configured for user pressing. A backlight module 200 is disposed between the base plate 110 and the key assembly 120 and configured to emit light toward the key assembly 120, thereby making the keyboard device 100 a backlit keyboard. Furthermore, the keyboard device 100 of this embodiment can be an external keyboard for desktop computers (e.g., a PS / 2 interface keyboard or a USB interface keyboard) or an input device including keys, but is not limited thereto. In other words, the concept of the keyboard device 100 disclosed herein can be applied to any electronic product that uses pressing as an input method.

[0059] like Figure 1 As shown, in this embodiment, the keyboard device 100 can be mainly divided into key components 120 located on both sides (e.g., key components 120a indicated by diagonal lines) and key components 120 located in the middle area of ​​the keyboard device 100 (e.g., key components 120b).

[0060] Please refer to Figure 2 as well as Figure 3 . Figure 2 For illustration Figure 1 A partial cross-sectional view of the keyboard device 100. Figure 3 For illustration Figure 1 A partial top view of the light guide plate 230. (See attached image.) Figure 2 and Figure 3 As shown, in this embodiment, the button assembly 120 is mounted on the backlight module 200 via a bracket 130. The connection between the button assembly 120 and the bracket 130 can employ various existing technologies (e.g., a scissor-type support guide structure), which will not be described in detail here. The backlight module 200 includes a circuit board 210, a light shield 220, and a light guide plate 230. The circuit board 210 has multiple light-emitting units located below the button assembly 120, wherein the first light-emitting unit 211 and the second light-emitting unit 212 are exposed... Figure 2 and Figure 3 The light-emitting element can be, but is not limited to, a light-emitting diode (LED). A light-shielding plate 220 is disposed above the circuit board 210 and has a shielding area 221. A light guide plate 230 is disposed between the circuit board 210 and the light-shielding plate 220, and includes a first single-bond light guide area 231, a second single-bond light guide area 232, and an opaque area 233. It should be noted that... Figure 3 In the middle, the two large dashed boxes indicate the button components 120a and 120b respectively, while the two small dashed boxes indicate the first single-key light guide area 231 and the second single-key light guide area 232 respectively.

[0061] For example, the first single-key light guide area 231 and the second single-key light guide area 232 are defined by the orthographic projections of the key assemblies 120a and 120b onto the light guide plate 230, but this disclosure is not limited thereto. The first single-key light guide area 231 has a first through-hole 231a to accommodate the first light-emitting unit 211. The second single-key light guide area 232 has a second through-hole 232a to accommodate the second light-emitting unit 212. An opaque area 233 is located between the first single-key light guide area 231 and the second single-key light guide area 232. For example, the opaque area 233 is at least the area of ​​the light guide plate 230 connected between the first single-key light guide area 231 and the second single-key light guide area 232. The shielding area 221 of the light shield 220 corresponds to the opaque area 233 in the vertical direction Dz.

[0062] Light emitted by the first light-emitting unit 211 enters the first single-key light-guiding area 231 of the light guide plate 230 through the inner wall of the first through hole 231a. Light emitted by the second light-emitting unit 212 enters the second single-key light-guiding area 232 of the light guide plate 230 through the inner wall of the second through hole 232a. In some embodiments, the bottoms of the first single-key light-guiding area 231 and the second single-key light-guiding area 232 respectively include microstructure portions (not shown). The microstructure portions surround the first light-emitting unit 211 and the second light-emitting unit 212 to guide the light emitted by the first light-emitting unit 211 and the second light-emitting unit 212 to the light-shielding plate 220. In practical applications, the light-shielding plate 220 is provided with two light-transmitting areas (not shown). These two light-transmitting areas correspond to the key assemblies 120a and 120b, respectively. In this way, the light emitted by the first light-emitting unit 211 and the second light-emitting unit 212 can accurately illuminate the aforementioned key assemblies 120a and 120b after passing through these two light-transmitting areas. For example, the areas of these two light-transmitting areas are smaller than the areas of the first single-key light guide area 231 and the second single-key light guide area 232, respectively, and are respectively aligned with the central areas of the aforementioned two button assemblies 120a and 120b, but this disclosure is not limited thereto. It should be noted that the aforementioned areas are the areas seen when looking down at the light shield 220 along the vertical direction Dz.

[0063] like Figure 2 As shown, in this embodiment, the backlight module 200 further includes a reflective layer 240. The reflective layer 240 is disposed between the light guide plate 230 and the circuit board 210, and is configured to reflect the light incident on the light guide plate 230 from the first light-emitting unit 211 and the second light-emitting unit 212 upwards, thereby effectively reducing light loss.

[0064] like Figure 1As shown, in this embodiment, the geometric center C11 of the first single-key light guide area 231 and the geometric center C12 of the second single-key light guide area 232 are located below the key assemblies 120a and 120b, respectively. As mentioned above, key assembly 120a is classified as key assembly 120 located in the middle area of ​​the keyboard device 100, while key assembly 120b is classified as key assembly 120 located in the side areas of the keyboard device 100. Therefore, the distance between the geometric center C11 of the first single-key light guide area 231 and the geometric center C00 of the light guide plate 230 is greater than the distance between the geometric center C12 of the second single-key light guide area 232 and the geometric center C00 of the light guide plate 230. The first light-emitting unit 211 and the second light-emitting unit 212 are substantially located at the geometric center C11 of the first single-key light guide area 231 and the geometric center C12 of the second single-key light guide area 232, respectively. Therefore, it can be seen that the first light-emitting unit 211 is farther away from the geometric center C00 of the light guide plate 230 than the second light-emitting unit 212.

[0065] It should be noted that when expansion and contraction occur due to temperature changes, the relative position of the light-emitting units located on both sides of the keyboard device 100 and the light guide plate 230 shifts significantly (and they are more likely to collide with the light guide plate 230). This can result in locally darker areas in the single-key light guide area on both sides of the keyboard device 100 (on the side farther from the light-emitting unit). Since the first light-emitting unit 211 is farther from the geometric center C00 of the light guide plate 230 than the second light-emitting unit 212, the luminous efficacy of the first light-emitting unit 211 is more easily affected by the expansion and contraction of the light guide plate 230 and the circuit board 210. In this embodiment, the backlight module 200 ensures that the current flowing through the first light-emitting unit 211 is greater than the current flowing through the second light-emitting unit 212. This allows the brightness of the light emitted by the first light-emitting unit 211 to be greater than the brightness of the light emitted by the second light-emitting unit 212, thus compensating for and improving the problem of uneven light intensity or reduced luminous efficacy caused by the expansion and contraction of the light guide plate 230 and the circuit board 210.

[0066] In some embodiments, the light-emitting units below the key assemblies 120 located on both sides of the keyboard device 100 may use the same circuit loop, while the light-emitting units below the key assemblies 120 located in the middle area of ​​the keyboard device 100 may use a different circuit loop. Different resistor configurations are used to control the current flowing through each light-emitting unit, thereby improving the overall luminous efficiency of the backlight module 200. In other embodiments, the circuit loops of all light-emitting units may also be independent, allowing for separate control of the current flowing through each light-emitting unit.

[0067] Compared to the second light-emitting unit 212, the first light-emitting unit 211 is more likely to collide with the light guide plate 230. In some embodiments, the area of ​​the first through-hole 231a of the light guide plate 230 used to accommodate the first light-emitting unit 211 can be larger than the area of ​​the second through-hole 232a of the light guide plate 230 used to accommodate the second light-emitting unit 212. By making the area of ​​the first through-hole 231a larger than the area of ​​the second through-hole 232a, the problem of the light guide plate 230 colliding with the first light-emitting unit 211 due to expansion and contraction can be effectively avoided. It should be noted that the aforementioned area is the area seen when looking down at the light guide plate 230 along the vertical direction Dz.

[0068] like Figure 2 and Figure 3 As shown, in this embodiment, the opaque area 233 of the light guide plate 230 has a plurality of expansion and contraction holes 233a corresponding to the shielding area 221. Although the expansion and contraction holes 233a are shown to be roughly circular in the figure, they can have any suitable shape, such as triangles, rectangles, polygons, ellipses, or similar shapes, but this disclosure is not limited thereto. By providing expansion and contraction holes 233a in the opaque area 233 of the light guide plate 230, the light guide plate 230 has space to release the deformation caused by expansion during expansion and contraction, thus effectively reducing the amount of expansion and contraction of the light guide plate 230 when the temperature changes. In some embodiments, in order to make the expansion and contraction holes 233a have a significant effect, the area of ​​the expansion and contraction holes 233a can be larger than the area of ​​the first through hole 231a or the area of ​​the second through hole 232a. It should be noted that the aforementioned area is the area seen when viewing the light guide plate 230 from above along the vertical direction Dz.

[0069] like Figure 2 As shown, in this embodiment, the first light-emitting unit 211 is spaced L1 and L2 from the right inner wall and left inner wall of the first through hole 231a, respectively, and the second light-emitting unit 212 is spaced L3 and L4 from the right inner wall and left inner wall of the second through hole 232a, respectively. It should be noted that regardless of whether the coefficient of thermal expansion of the light guide plate 230 or the circuit board 210 is larger, both will contract inwards when heated, especially along their long sides. Therefore, for the first through hole 231a located below the key assembly 120a on the left side of the keyboard device 100, the distances L1 and L2 can be pre-designed to be different so that the position of the first light-emitting unit 211 after expansion and contraction is closer to the center of the first through hole 231a. For example, if it is known that the first light-emitting unit 211 shifts towards the right inner wall of the first through hole 231a after expansion and contraction, then the distance L1 can be pre-designed to be greater than the distance L2, and vice versa. The through-hole located below the key assembly 120a on the right side of the keyboard device 100 is reversed. For the second through-hole 232a located below the key assembly 120b in the middle area of ​​the keyboard device 100, the distance L3 can be substantially equal to the distance L4.

[0070] like Figure 2 As shown, in this embodiment, the expansion and contraction hole 233a is located between the first light-emitting unit 211 and the second light-emitting unit 212, and is configured to block light crosstalk between the first light-emitting unit 211 and the second light-emitting unit 212. That is, light emitted from the first light-emitting unit 211 and traveling towards the second light-emitting unit 212 can be blocked by the expansion and contraction hole 233a to avoid entering the second single-bond light-guiding area 232, and light emitted from the second light-emitting unit 212 and traveling towards the first light-emitting unit 211 can also be blocked by the expansion and contraction hole 233a to avoid entering the first single-bond light-guiding area 231. Furthermore, the light-shielding plate 220 covers the upper end of the expansion and contraction hole 233a. The reflective layer 240 covers the lower end of the expansion and contraction hole 233a. This prevents light emitted by the first light-emitting unit 211 and the second light-emitting unit 212 from leaking through the upper and lower ends of the expansion and contraction hole 233a after entering it.

[0071] Please refer to Figure 4 It is a drawing Figure 1 Another partial cross-sectional view of the keyboard device 100. (See diagram below.) Figure 4 As shown, in this embodiment, the keyboard device 100 further includes a first connector 250 and a second connector 260. A light-shielding plate 220 is bonded to a light guide plate 230 via the first connector 250. A circuit board 210 is bonded to the light guide plate 230 via the second connector 260. Specifically, the first connector 250 and the second connector 260 are disposed corresponding to the opaque area 233 of the light guide plate 230, and overlap vertically with the shielding area 221 (i.e., overlap in the vertical direction Dz). This ensures that the light-shielding plate 220, the circuit board 210, and the light guide plate 230 have substantially the same or similar expansion and contraction amounts when the temperature changes, thereby further ensuring that the light guide plate 230 will not collide with the first light-emitting unit 211. In other embodiments, the first connector 250 and the second connector 260 only partially overlap in the vertical direction Dz. In practical applications, one of the first connector 250 and the second connector 260 may be omitted.

[0072] Please refer to Figure 5 as well as Figure 6 . Figure 5 A partial cross-sectional view is shown for illustrating a keyboard device 100 according to another embodiment of this disclosure. Figure 6 For illustration Figure 5 A partial top view of the light guide plate 230 in this embodiment. This embodiment is different from... Figure 4The difference in the illustrated implementation is that the first connector 250 and the second connector 260 do not overlap in their vertical positions corresponding to the shielding area 221. By staggering the first connector 250 and the second connector 260, the overall thickness of the backlight module 200 can be avoided.

[0073] like Figure 6 As shown, in this embodiment, taking the button assembly 120a as an example, the expansion and contraction holes 233a are disposed at the center of the four sides of the button assembly 120a, while the first connecting member 250 and the second connecting member 260 are disposed at the corners of the button assembly 120a. Therefore, in addition to the expansion and contraction holes 233a providing the aforementioned light-blocking effect in the horizontal directions Dx and Dy, the first connecting member 250 and the second connecting member 260 can also provide a light-reducing effect in the direction inclined to the horizontal directions Dx and Dy.

[0074] Please refer to Figure 7 It is a drawing Figure 1 Another partial cross-sectional view of the keyboard device 100. (See diagram below.) Figure 7 As shown, in this embodiment, the circuit board 210 has an expansion / contraction hole 213 corresponding to the shielding area 221. The expansion / contraction hole 213 extends through the reflective layer 240. The vertical position of the expansion / contraction hole 213 on the circuit board 210 does not overlap with that of the expansion / contraction hole 233a on the light guide plate 230 to avoid light leakage. By providing the expansion / contraction hole 213 on the circuit board 210, in addition to effectively reducing the expansion / contraction of the circuit board 210 when the temperature changes, the expansion / contraction hole 213 can also serve as a vent for air between the light guide plate 230 and the circuit board 210.

[0075] In some other embodiments, the vertical positions of the expansion and contraction hole 213 on the circuit board 210 and the expansion and contraction hole 233a on the light guide plate 230 may only partially overlap, and the expansion and contraction hole 213 may not extend through the reflective layer 240.

[0076] Please refer to Figure 8 It is a drawing Figure 1 Another top view of the keyboard device 100. (See image below.) Figure 8 As shown, in this embodiment, the opaque area 233 further has expansion and contraction holes 233a1 and 233a2 corresponding to the shielding area 221. To keep the diagram concise and clear, Figure 8 The middle part is an abbreviated drawing. Figure 3The expansion and contraction hole 233a is essentially circular. In some embodiments, only expansion and contraction holes 233a1 and 233a2 may be provided, without expansion and contraction hole 233a. The geometric center C13 of expansion and contraction hole 233a1 and the geometric center C14 of expansion and contraction hole 233a2 are respectively equidistant from the geometric center C00 of light guide plate 230. The distance between the geometric center C13 of expansion and contraction hole 233a1 and the first short side E1 of light guide plate 230 is equal to the distance between the geometric center C14 of expansion and contraction hole 233a2 and the second short side E2 of light guide plate 230. The distance between the geometric center C13 of expansion and contraction hole 233a1 and the second short side E2 of light guide plate 230 is equal to the distance between the geometric center C14 of expansion and contraction hole 233a2 and the first short side E1 of light guide plate 230. The distance between the geometric center C13 of the expansion and contraction hole 233a1 and the first long side E3 of the light guide plate 230 is equal to the distance between the geometric center C14 of the expansion and contraction hole 233a2 and the second long side E4 of the light guide plate 230. Similarly, the distance between the geometric center C13 of the expansion and contraction hole 233a1 and the second long side E4 of the light guide plate 230 is equal to the distance between the geometric center C14 of the expansion and contraction hole 233a2 and the first long side E3 of the light guide plate 230. In other words, the expansion and contraction holes 233a1 and 233a2 are symmetrically positioned on the light guide plate 230 in the horizontal direction Dx and centered in the horizontal direction Dy.

[0077] Furthermore, the expansion / contraction hole 233a1 has extensions 233a11 and 233a12 extending along the horizontal direction Dx toward the first short side E1 and the second short side E2, respectively, and extensions 233a13 and 233a14 extending along the horizontal direction Dy toward the first long side E3 and the second long side E4, respectively. Additionally, the expansion / contraction hole 233a2 has extensions 233a21 and 233a22 extending along the horizontal direction Dx toward the first short side E1 and the second short side E2, respectively, and extensions 233a23 and 233a24 extending along the horizontal direction Dy toward the first long side E3 and the second long side E4, respectively. The extensions 233a11, 233a12, 233a13, 233a14, 233a21, 233a22, 233a23, and 233a24 of the expansion and contraction holes 233a1 and 233a2 (as shown by the dashed lines) divide the light guide plate 230 into six regions, each region having a geometric center C01, C02, C03, C04, C05, and C06, respectively. Through this structural configuration, the expansion and contraction holes 233a1 and 233a2 effectively interrupt the continuous expansion and contraction of the light guide plate 230 in the horizontal directions Dx and Dy, and effectively reduce the amount of expansion and contraction of the light guide plate 230 when the temperature changes. In practical applications, the number of regions into which the light guide plate 230 is divided can be flexibly changed (by altering the number of expansion and contraction holes 233a1 and 233a2). Furthermore, the more regions are divided, the less the light guide plate 230 expands and contracts when the temperature changes.

[0078] Please refer to Figure 9 It is a drawing Figure 8 A partial top view of the keyboard device 100. (See attached image.) Figure 9 As shown, in this embodiment, multiple expansion and contraction holes 233a3 and multiple expansion and contraction holes 233a4 are located around the geometric center C00 of the light guide plate 230. Taking an expansion and contraction hole 233a3 with a geometric center C21 and an expansion and contraction hole 233a4 with a geometric center C22 as examples, the distance between the geometric center C21 of the expansion and contraction hole 233a3 and the geometric center C00 of the light guide plate 230 is smaller than the distance between the geometric center C22 of the expansion and contraction hole 233a4 and the geometric center C00 of the light guide plate 230. It should be noted that when the temperature changes, the expansion and contraction amount is greater closer to the geometric center C00 of the light guide plate 230 and smaller further away from the geometric center C00 of the light guide plate 230. By making the area of ​​the expansion and contraction hole 233a3 larger than the area of ​​the expansion and contraction hole 233a4, the expansion and contraction amount of the light guide plate 230 during temperature changes can be made more uniform. Furthermore, by making the area of ​​the expansion and contraction hole 233a4, which is relatively far from the geometric center C00 of the light guide plate 230, smaller, a balance can be achieved between the expansion and contraction of the light guide plate 230 and its structural strength. It should be noted that the aforementioned area is the area seen when viewing the light guide plate 230 from above along the vertical direction Dz.

[0079] In some embodiments, when the light guide plate 230 is divided into the aforementioned six regions, the expansion and contraction holes 233a3 and 233a4 can also be provided based on the geometric centers C01, C02, C03, C04, C05, and C06 of each region. For example, in the region with the geometric center C01, the expansion and contraction hole 233a3 with a larger area can be provided closer to the geometric center C01, while the expansion and contraction hole 233a4 with a smaller area can be provided farther away from the geometric center C01, and the same applies to other regions.

[0080] From the detailed description of the specific embodiments disclosed above, it is evident that in the backlight module of this disclosure, by making the current flowing through the first light-emitting unit, which is farther from the geometric center of the light guide plate, greater than the current flowing through the second light-emitting unit, which is closer to the geometric center of the light guide plate, the problem of uneven light energy or reduced light efficiency caused by the expansion and contraction of the light guide plate and the circuit board in the first light-emitting unit can be improved. By making the area of ​​the first through-hole in the light guide plate used to accommodate the first light-emitting unit greater than the area of ​​the second through-hole used to accommodate the second light-emitting unit, the problem of the light guide plate colliding with the first light-emitting unit due to expansion and contraction can be effectively avoided. By providing expansion and contraction holes in the opaque area of ​​the light guide plate, the amount of expansion and contraction of the light guide plate when the temperature changes can be effectively reduced. By covering the upper and lower ends of the expansion and contraction holes with a light-shielding plate and a reflective layer respectively, light leakage at the expansion and contraction holes can be avoided. By making the area of ​​the expansion and contraction holes farther from the geometric center of the light guide plate smaller, a balance can be achieved between the amount of expansion and contraction and the structural strength of the light guide plate. By incorporating expansion and contraction holes on the circuit board, the expansion and contraction of the circuit board during temperature changes can be effectively reduced. These holes also serve as venting holes for air between the light guide plate and the circuit board. By bonding the connectors between the light shield and the light guide plate, and / or between the circuit board and the light guide plate, at least one of the light shield and the circuit board can have substantially the same or similar expansion and contraction as the light guide plate during temperature changes, further ensuring that the light guide plate will not collide with the first light-emitting unit. By misaligning the connectors bonded between the light shield and the light guide plate with those bonded between the circuit board and the light guide plate, the overall thickness of the backlight module can be prevented from becoming excessive.

[0081] Although the present disclosure has been described above with reference to embodiments, it is not intended to limit the present disclosure. Any person skilled in the art may make various modifications and alterations without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the scope defined in the appended claims.

Claims

1. A backlight module, characterized in that, Include: The circuit board is equipped with a first light-emitting unit and a second light-emitting unit; A light-shielding plate, disposed above the circuit board, and having a shielding area; and A light guide plate, disposed between the circuit board and the light shield, includes: The first single-bond light-guiding area has a first through hole to accommodate the first light-emitting unit; The second single-bonded light-guiding area has a second through-hole to accommodate the second light-emitting unit; and The opaque area has a first expansion and contraction hole corresponding to the shaded area; The distance between the geometric center of the first single-bond light guide area and the geometric center of the light guide plate is greater than the distance between the geometric center of the second single-bond light guide area and the geometric center of the light guide plate. The current flowing through the first light-emitting unit is greater than the current flowing through the second light-emitting unit.

2. The backlight module as described in claim 1, characterized in that, The area of ​​the first through hole is larger than the area of ​​the second through hole.

3. The backlight module as described in claim 1, characterized in that, The area of ​​the first expansion orifice is greater than the area of ​​the first through hole or the area of ​​the second through hole.

4. The backlight module as described in claim 1, characterized in that, It further includes a reflective layer disposed between the light guide plate and the circuit board, wherein the light shield covers the upper end of the first expansion and contraction hole, and the reflective layer covers the lower end of the first expansion and contraction hole.

5. The backlight module as described in claim 1, characterized in that, The opaque area further has a second expansion hole corresponding to the shielding area. The distance between the geometric center of the first expansion hole and the geometric center of the light guide plate is less than the distance between the geometric center of the second expansion hole and the geometric center of the light guide plate, and the area of ​​the first expansion hole is greater than the area of ​​the second expansion hole.

6. The backlight module as described in claim 5, characterized in that, The circuit board has a third expansion hole corresponding to the shielding area, and the vertical position of the third expansion hole does not overlap or partially overlaps with the first expansion hole or the second expansion hole.

7. The backlight module as described in claim 1, characterized in that, The opaque area further has a second expansion hole corresponding to the shielding area. The geometric centers of the first and second expansion holes are equidistant from the geometric center of the light guide plate. The distance between the geometric center of the first expansion hole and the first short side of the light guide plate is equal to the distance between the geometric center of the second expansion hole and the second short side of the light guide plate. The distance between the geometric center of the first expansion hole and the first long side of the light guide plate is equal to the distance between the geometric center of the second expansion hole and the second long side of the light guide plate.

8. The backlight module as described in claim 1, characterized in that, The first expansion orifice is located between the first light-emitting unit and the second light-emitting unit, and is configured to block optical crosstalk between the first light-emitting unit and the second light-emitting unit.

9. The backlight module as described in claim 1, characterized in that, The light shield and one of the circuit boards are bonded to the light guide plate through a first connector.

10. The backlight module as described in claim 9, characterized in that, The light-shielding plate is bonded to the light guide plate via a second connector, along with another component in the circuit board.

11. The backlight module as described in claim 10, characterized in that, The first connector and the second connector do not overlap or partially overlap in their vertical positions corresponding to the shielding area.

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