Backlight module of luminous keyboard

Abstract

The circuit board is provided with a first loop, a second loop, a converging part and a guide connecting part, the first loop and the second loop are electrically connected to the converging part, the converging part is electrically connected with the guide connecting part, and the first loop is provided with a first line section; the light guide plate is arranged above the circuit board and is provided with a first light guide area and a second light guide area, and the first light guide area is arranged above the first circuit section; the plurality of light-emitting elements are arranged on the first line section in parallel; and the resistor unit is provided with a first resistor and a second resistor, the first resistor is arranged in the first loop, and the second resistor is arranged in the second loop. The sum of the line impedance value of the first loop and the impedance value of the first resistor is approximately equal to the sum of the line impedance value of the second loop and the impedance value of the second resistor. The guide connection part is connected with an external control chip and is used for transmitting a control signal.

Description

Technical Field

[0001] The present utility model relates to a backlight module, and particularly to a backlight module for a backlit keyboard. Background Art

[0002] The backlight modules of currently popular backlit keyboards mainly include four major components, which, from the keyboard downwards in sequence, include a light-shielding sheet, a light guide plate (Light Guide Plate, LGP), a reflective sheet, and a light bar. In this type of backlight module, all the light-emitting elements are placed on the same light bar, and the light bar is placed near the center of the backlight module, so that the light emitted by the light-emitting elements on the light bar is incident into the light guide plate on both sides, and then the light is distributed on the back side of the keyboard through the light guide plate to form the keyboard backlight.

[0003] However, since this type of backlit keyboard has problems of relatively thick thickness and uneven light, another architecture of the light-emitting module of the backlit keyboard has been proposed currently. In this architecture, the light-emitting elements are mounted on a circuit board, and a multi-layer structure of a keycap, a scissor foot, an iron plate, a light-shielding sheet (Black Matrix, BM), a light guide plate, a reflective sheet, and a circuit board is stacked from top to bottom in sequence. However, since the minimum height of the light-emitting diode (LED) of the current light-emitting element is 0.15 mm, in order to reduce the overall thickness and improve the light-emitting brightness and uniformity, it is necessary to consider further improvement of its design method.

[0004] In addition, the current backlit keyboard is equipped with resistors to control the light-emitting brightness of the overall backlight module. If there are N light-emitting elements, N resistors will be equipped to control the brightness of each light-emitting element respectively to control the overall brightness. However, when the number of light-emitting elements is large, the component cost will increase, resulting in the product not having a cost advantage.

[0005] Therefore, it is necessary to propose a new design of the backlight module for a backlit keyboard, which can improve the light-emitting brightness of the keyboard and make the light source evenly distributed. Summary of the Utility Model

[0006] In view of this, the present utility model proposes a backlight module for a backlit keyboard. The backlight module for the backlit keyboard of the present utility model can improve the brightness and make the optical coupling more uniform.

[0007] The present utility model provides a backlight module for a luminous keyboard, which includes: a circuit board having a first circuit, a second circuit, a converging portion, and a connecting portion. The first circuit and the second circuit are electrically connected to the converging portion, and the converging portion is electrically connected to the connecting portion. The first circuit has a first line segment, and the second circuit has a second line segment; a light guide plate is disposed above the circuit board and has a first light guide area and a second light guide area. The first light guide area is disposed above the first line segment, and the second light guide area is disposed above the second line segment; a plurality of light-emitting elements are connected in parallel to the first line segment and connected in parallel to the second line segment; and a resistor unit has a first resistor and a second resistor. The first resistor is disposed in the first circuit, and the second resistor is disposed in the second circuit; wherein, the sum of the line impedance value of the first circuit and the impedance value of the first resistor is approximately equal to the sum of the line impedance value of the second circuit and the impedance value of the second resistor; the connecting portion is connected to an external control chip, and the connecting portion is used to transmit control signals.

[0008] In some embodiments, the first light guide area includes a first sub-area and a second sub-area arranged adjacent to each other. The first sub-area includes a first single-key light guide area and a second single-key light guide area disposed on both sides thereof. One of the light-emitting elements is disposed on one side of the first single-key light guide area and emits a light beam toward the first single-key light guide area and the second single-key light guide area.

[0009] In some embodiments, the first sub-area has a light conduction channel, and the light conduction channel passes through the first single-key light guide area or the second single-key light guide area.

[0010] In some embodiments, the first sub-area is disposed adjacent to one side edge of the light guide plate. The distance between the first single-key light guide area and the side edge is greater than the distance between the second single-key light guide area and the side edge, and the microstructure density of the first single-key light guide area is less than the microstructure density of the second single-key light guide area.

[0011] In some embodiments, the light guide plate has a third light guide area, and the third light guide area has a third single-key light guide area. The area of the third single-key light guide area is greater than the area of the first single-key light guide area or the area of the second single-key light guide area, and the converging portion is disposed in the area on the circuit board corresponding vertically to the third light guide area.

[0012] In some embodiments, the number of the light-emitting elements on the first line segment is equal to the number of the light-emitting elements on the second line segment. The line length from the center position of the light-emitting elements in the first circuit to the converging portion is greater than the line length from the center position of the light-emitting elements in the second circuit to the converging portion, and the impedance value of the first resistor is less than the impedance value of the second resistor.

[0013] In some embodiments, the first light guide area includes a plurality of single-key light guide areas, the second light guide area includes a plurality of single-key light guide areas, a first ratio of the total microstructure area of the single-key light guide areas in the first light guide area divided by the number of the light-emitting elements on the first circuit segment is greater than a second ratio of the total microstructure area of the single-key light guide areas in the second light guide area divided by the number of the light-emitting elements on the second circuit segment, and the impedance value of the first resistor is greater than the impedance value of the second resistor. In some embodiments, the number of the light-emitting elements on the first circuit segment is less than the number of the light-emitting elements on the second circuit segment, the line length from the center positions of the light-emitting elements in the first loop to the converging portion is approximately equal to the line length from the center positions of the light-emitting elements in the second loop to the converging portion, and the impedance value of the first resistor is greater than the impedance value of the second resistor.

[0014] In some embodiments, the number of the light-emitting elements on the first circuit segment is equal to the number of the light-emitting elements on the second circuit segment, the first light guide area includes a plurality of single-key light guide areas, the second light guide area includes a plurality of single-key light guide areas, the total microstructure area of the single-key light guide areas in the first light guide area is greater than the total microstructure area of the single-key light guide areas in the second light guide area, and the impedance value of the first resistor is greater than the impedance value of the second resistor.

[0015] In some embodiments, the first resistor and the second resistor are electrically connected to the converging portion.

[0016] In summary, the backlight module of the light-emitting keyboard of the present invention divides the keyboard into multiple areas corresponding to the arrangement of the keycaps, divides the light guide plate into multiple light guide areas corresponding to the multiple areas, and the circuit board also sets multiple loops corresponding to the multiple areas. Different areas have different light-emitting areas and different line lengths. The backlight module of the present invention can set different numbers of light-emitting elements and light guide areas with different microstructure areas corresponding to different light-emitting areas. Furthermore, the backlight module of the present invention can set resistors with different impedance values corresponding to different line lengths to make the current in each loop uniform and stable. In other words, the backlight module of the present invention adjusts the number of light-emitting elements, the microstructure area of the light guide area, and the total impedance value of the loop corresponding to different areas, so as to improve the brightness of the backlight module and make the light coupling more uniform, and reduce the brightness difference between different light guide areas to a level that cannot be distinguished by the naked eye (for example, the brightness difference is within 50%).

[0017] It should be noted that, as used in this case, terms such as "first", "second", "third", etc. describe various components, components, regions, layers and / or parts, and these components, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another. Unless the context clearly indicates otherwise, the terms such as "first", "second", "third" used in this article do not imply order or sequence. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the backlight module of the light-emitting keyboard of the present utility model;

[0019] Figure 2 For the backlight module along Figure 1 Partial schematic diagram of the A-A section line;

[0020] Figure 3 It is a top view schematic diagram of the light guide plate and the circuit board of the backlight module;

[0021] Figure 4A It is a partial enlarged schematic diagram of the light guide area and the circuit board of this embodiment;

[0022] Figure 4B It is a partial enlarged schematic diagram of the light guide area and the circuit board of this embodiment;

[0023] Figure 4C It is a partial enlarged schematic diagram of the light guide area and the circuit board of this embodiment;

[0024] Figure 5 It is a top view schematic diagram of the light guide plate and the circuit board of the backlight module;

[0025] Figure 6 It is a top view schematic diagram of the light guide plate and the circuit board of the backlight module;

[0026] Figure 7 It is a top view schematic diagram of the light guide plate and the circuit board of the backlight module;

[0027] Figure 8 It is a top view schematic diagram of the variant state of the light guide plate and the circuit board of the backlight module;

[0028] Among them, reference numerals:

[0029] 1: Backlight module;

[0030] 2: Circuit board;

[0031] 21, 22, 25, 26: Circuits;

[0032] 211, 221: Circuit segments;

[0033] 23: Converging section;

[0034] 24: Conductive connection section;

[0035] 25: Reflective layer;

[0036] 27: External control chip;

[0037] 3: Light guide plate;

[0038] 31, 31A, 32, 33, 34, 35: Light guide regions;

[0039] 311, 312, 321, 322, 323: Sub-regions;

[0040] 311A, 311B, 311C, 323A, 323B, 331A: Single-key light guide regions;

[0041] 41, 41A, 42, 43, 44: Light-emitting elements;

[0042] 5: Resistance unit;

[0043] 51, 52, 53, 54: Resistors;

[0044] 6: Light-shielding sheet;

[0045] A1, A2, A2’, A3: Regions;

[0046] S1, S2: Sides. Detailed implementation manner

[0047] As used herein, terms such as "first", "second", "third", etc. describe various components, components, regions, layers, and / or parts, and these components, components, regions, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or part from another. Unless the context clearly indicates otherwise, terms such as "first", "second", "third" used herein do not imply order or sequence.

[0048] Used herein and not otherwise defined, the term "approximately equal to" is used to describe and account for small variations caused by factors such as existing manufacturing process errors, temperature, and environment. When combined with an event or situation, this term can include the precise moment when the event or situation occurs, as well as the event or situation occurring up to a close approximation point. For example, when combined with a numerical value, this term can include a variation range less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.

[0049] A backlit keyboard generally includes a keyboard component, a bottom plate, and a backlight module, but this is not restrictive. The keyboard component may include, for example, a plurality of keycaps of different sizes, such as function keys, number keys, letter keys, input keys, etc. On the top surface of each keycap, there may be a symbol annotation corresponding to the character or function of the keycap. The symbol annotation can be any symbol required for the keyboard function, such as but not limited to English letters, numbers, special symbols, or symbol codes of various input methods. The symbol annotation area of the keycap can be designed to be semi-translucent, but this is not restrictive. Thus, the light emitted by the backlight module can pass through the light-emitting area of the characters to make the keycaps emit light for the user to view and identify.

[0050] The bottom plate is located between the keyboard component and the backlight module, and the material can be, for example, but not limited to various metals such as iron, stainless steel, nickel, copper, or materials such as resin, plastic, rubber, etc. The bottom plate can be designed to be light-transmissive or light-opaque. The bottom plate may be provided with a plurality of openings corresponding to the plurality of keycaps. The openings can be round holes, squares, polygons, or other shapes.

[0051] Figure 1 FIG. is a schematic diagram of the backlight module of the backlit keyboard of the present invention. Figure 2 For the backlight module along Figure 1 Partial schematic diagram of the A-A section line. Figure 3 FIG. is a top view schematic diagram of the light guide plate and the circuit board of the backlight module. As Figure 1 , Figure 2 And Figure 3 As shown, the backlight module 1 generally includes a circuit board 2, a light guide plate 3, a plurality of light-emitting elements 41, 42, and a resistor unit 5. In some embodiments, the backlight module 1 may further include a light-shielding sheet 6. The light-shielding sheet 6 has the properties of blocking light and reflecting light, and is used to control the actual light-emitting area.

[0052] The circuit board 2 may have, for example, a surface facing the light guide plate 3 and a surface facing away from the light guide plate 3. In some embodiments, the surface of the circuit board 2 facing the light guide plate 3 may be coated with a reflective layer 25 as a reflective and light-shielding material to reflect some of the light emitted by the light-emitting elements 41, 42 to the light guide plate 3, but this is not restrictive. The through holes of the light guide plate 3 are larger than the sizes of the light-emitting elements 41, 42, and the reflective layer 25 of the circuit board 2 may be exposed in the through holes of the light guide plate 3. The light-emitting elements 41, 42 may be close to or in contact with the reflective layer 25, so that the light is directly reflected by the reflective layer 25, improving the light utilization rate. The reflective layer 25 can be white or other colors that are beneficial for reflection. The reflective layer and the circuit board 2 can be integrally formed, making the light-incident area smoother to reduce losses during light incidence and improve the optimized utilization of the light input efficiency. The circuit board 2 can be, for example, but not limited to a flexible printed circuit board (FPC).

[0053] In this embodiment, the circuit board 2 has a plurality of circuits 21, 22, a converging portion 23, and a connection portion 24. One ends of the circuits 21, 22 are electrically connected to the converging portion 23, the other ends of the circuits 21, 22 are electrically connected to the connection portion 24, and the converging portion 23 is electrically connected to the connection portion 24. The connection portion 24 is adjacent to the long side of the circuit board 2, and the converging portion 23 is adjacent to the connection portion 24. The connection portion 24 can be connected to an external control chip 27, and the connection portion 24 is used to transmit control signals.

[0054] It is worth mentioning that in this embodiment, the circuit board 2 having 13 circuits is taken as an example for illustration. For example, Figure 3 five circuits are provided on the left side in [description], and eight circuits are provided on the right side, but it is not intended to limit the present invention. The number and design of the circuits are for adjusting the number of light-emitting elements, the microstructure area of the light guide area, and the total impedance value of the circuits in a coordinated manner, so as to make the current flowing through the light-emitting elements in each area uniform and stable. Therefore, corresponding to different design methods, different numbers of circuits and circuit designs can also be used, which is not restrictive here. In some embodiments, the circuit 21 has a circuit segment 211, and the circuit 22 has a circuit segment 221.

[0055] The light guide plate 3 is disposed above the circuit board 2. The light guide plate 3 has light guide areas 31, 32. The light guide area 31 is disposed above the circuit segment 211, and the light guide area 32 is disposed above the circuit segment 221. It is worth mentioning that in this embodiment, corresponding to the circuits, the light guide plate is divided into 13 regions. For example, Figure 3 the uppermost row in [description] is divided into three regions, and each of the other rows is divided into left and right two regions for illustration, but it is not intended to limit the present invention. Similarly, the purpose of the partitioning is to adjust the number of light-emitting elements, the microstructure area of the light guide area, and the total impedance value of the circuits in a coordinated manner, so as to make the current flowing through the light-emitting elements in each area uniform and stable. Therefore, corresponding to different design methods, different numbers of partitions or partitions of different shapes can also be used, which is not restrictive here.

[0056] The light-emitting elements 41, 42 can be, for example, side view mini LEDs, which can emit a single direct light to directly inject most of the light into the light guide plate 3 to obtain a better light coupling effect. In some embodiments, the light-emitting elements 41 are connected in parallel to the circuit segment 211 of the circuit 21 and are located in the light guide area 31. The light-emitting elements 42 are connected in parallel to the circuit segment 221 of the circuit 22 and are located in the light guide area 32. For example, two light-emitting elements 41 of the circuit 21 are connected in parallel and then one end is connected to the converging portion 23, and the other end is connected to the connection portion 24. Similarly, three light-emitting elements 42 of the circuit 22 are connected in parallel and then one end is connected to the converging portion 23, and the other end is connected to the connection portion 24.

[0057] Hereinafter, the setting manners of the light guide area and the light-emitting element will be described in detail, which are only exemplary and not intended to limit the present invention.

[0058] Figure 4A and Figure 4B are partial enlarged schematic views of the light guide area and the circuit board of this embodiment. As Figure 3 and Figure 4A shown, the light guide area 31 will be taken as an example for illustration herein. The light guide area 31 may include adjacent sub-areas 311 and 312. Two light-emitting elements 41 are connected in parallel between the sub-area 311 and the sub-area 312. The sub-area 311 is located on one side of the light guide area 31 (for example, Figure 4A the left side) and is disposed adjacent to one side edge S1 of the light guide plate 3 (for example, Figure 3 the left short side of the light guide plate 3), while the sub-area 312 is located on the other side of the light guide area 31 (for example, Figure 4A the right side). Hereinafter, the sub-area 311 will be taken as an example for illustration, but it is not intended to limit the present invention.

[0059] The sub-area 311 may include, for example, a single-key light guide area 311A, a single-key light guide area 311B, and a single-key light guide area 311C. The single-key light guide area 311B is disposed between the single-key light guide area 311A and the single-key light guide area 311C, and the single-key light guide area 311A and the single-key light guide area 311C are respectively disposed on both sides of the sub-area 311. The single-key light guide area 311A is adjacent to the light-emitting element 41, and the single-key light guide area 311C is far from the light-emitting element 41 and adjacent to the side edge S1 of the light guide plate 3. In other words, the distance between the single-key light guide area 311A and the side edge S1 is greater than the distance between the single-key light guide area 311C and the side edge S1.

[0060] Furthermore, one of the light-emitting elements 41 connected in parallel (such as Figure 4A the left light-emitting element 41) is disposed on one side of the single-key light guide area 311A and emits light toward the single-key light guide area 311A and the single-key light guide area 311C. Since the single-key light guide area 311A is closer to the light-emitting element 41 and the single-key light guide area 311C is farther from the light-emitting element 41, the light energy received by the single-key light guide area 311A will be greater than the light energy received by the single-key light guide area 311C. Therefore, the microstructure density of the single-key light guide area 311A will be less than the microstructure density of the single-key light guide area 311C. That is, corresponding to the distance from the light-emitting element 41, the microstructure density of the single-key light guide area 311A will be the smallest, the microstructure density of the single-key light guide area 311C will be the largest, and the microstructure density of the single-key light guide area 311B will be between the single-key light guide area 311A and the single-key light guide area 311C.

[0061] Similarly, as Figure 4BAs shown, in this embodiment, any one of the single-button light guide areas 311A, 311B, and 311C can be divided into upper, middle, and lower areas. Taking the single-button light guide area 311A as an example, the single-button light guide area 311A can be divided into areas A1, A2, and A3 (such as Figure 4B the upper, middle, and lower areas therein). In one embodiment, the areas A1, A2, and A3 can be equal divisions of the area of the single-button light guide area 311A, but not limited to equal division, and the light-emitting element 41 is disposed on one side of the area A2. For the same reason as above, since the area A2 is closer to the light-emitting element 41, the microstructure density of the area A2 will be less than the microstructure densities of the areas A1 and A3. On the other hand, since the single-button light guide area 311C is the farthest from the light-emitting element 41, the microstructure density of the area A2' corresponding to the light-emitting element 41 in the single-button light guide area 311C will be greater than the microstructure density of the area A2 in the single-button light guide area 311A.

[0062] In addition, overall, the arrangement of the microstructures in the sub-area 312 is similar to that in the sub-area 311, and the difference lies in the mirror image relationship centered on the light-emitting element 41, which will not be elaborated herein.

[0063] Generally speaking, the light guide area 31 as a whole can be divided into three equal-area regions, namely upper, middle, and lower regions, and the light-emitting element 41 can be correspondingly disposed in the middle region. Therefore, the microstructure density in the middle region of the light guide area 31 will be less than that in the upper region and / or the lower region. In other words, the sub-areas 311 and 312 have light conduction channels (regions with a smaller microstructure density), and the light conduction channels will pass through the single-button light guide area 311A, the single-button light guide area 311B, and / or the single-button light guide area 311C.

[0064] Figure 4C This is a partial enlarged schematic diagram of the light guide area and the circuit board of this embodiment. As Figure 3 and Figure 4C shown, the light guide area 32 on the right side is taken as an example for illustration herein. The light guide area 32 can include a sub-area 321, a sub-area 322, and a sub-area 323. The sub-area 321 is adjacent to the light guide area 31, the sub-area 322 is disposed between the sub-area 321 and the sub-area 323, and the sub-area 323 is adjacent to the other side edge S2 of the light guide plate 3 (such as Figure 3 the right short side of the light guide plate 3).

[0065] Since the area of the light guide area 32 is larger than the area of the light guide area 31, three light-emitting elements 42 are correspondingly disposed for the light guide area 32, and the three light-emitting elements 42 are disposed on the second line segment 221 of the loop 22. Two light-emitting elements 42 are connected in parallel between the sub-area 321 and the sub-area 322, and one light-emitting element 42 is disposed on one side of the sub-area 323. The arrangement of the sub-area 321 and the sub-area 322 in the light guide area 32 is similar to the arrangement of the sub-area 311 and the sub-area 312 in the light guide area 31, which will not be elaborated herein.

[0066] On the other hand, the sub-region 323 may, for example, have only two single-key light-guiding regions, namely the single-key light-guiding region 323A and the single-key light-guiding region 323B. For the same reason as above, since the single-key light-guiding region 323A is closer to the light-emitting element 42 and the single-key light-guiding region 323B is farther from the light-emitting element 42, the microstructure density of the single-key light-guiding region 323A will be less than that of the single-key light-guiding region 323B.

[0067] Please refer again to Figure 3 As shown, the light guide plate 3 may further have a light-guiding region 33. The light-guiding region 33 has a single-key light-guiding region 331A. The area of the single-key light-guiding region 331A is larger than that of any one of the single-key light-guiding regions in other light-guiding regions (for example Figure 4A the single-key light-guiding regions 311A, 311B, 311C or as Figure 4C the single-key light-guiding regions 323A, 323B). The converging portion 23 is disposed in the region on the circuit board 2 vertically corresponding to the light-guiding region 33. The single-key light-guiding region 331A may, for example, correspond to the key cap of the space bar.

[0068] Furthermore, the resistance unit 5 of the backlight module, for example, has a resistor 51 and a resistor 52. The resistor 51 is disposed in the loop 21, and the resistor 52 is disposed in the loop 22. And the resistor 51 and the resistor 52 are disposed at the converging portion 23.

[0069] Hereinafter, the setting method of the resistances of different light-guiding regions will be described in detail. It is only illustrative and not intended to limit the present invention.

[0070] First, as Figure 3 shown, taking the loops 21 and 22 corresponding to the light-guiding regions 31 and 32 on the same row as an example for explanation. When the number of light-emitting elements 41 (for example, two) provided in the light-guiding region 31 is less than the number of light-emitting elements 42 (for example, three) provided in the light-guiding region 32, the total impedance value of the light-emitting elements 41 in the loop 21 will be less than the total impedance value of the light-emitting elements 42 in the loop 22. In addition, the line length from the center position of these light-emitting elements 41 in the loop 21 to the converging portion 23 is approximately equal to the line length from the center position of these light-emitting elements 42 in the loop 22 to the converging portion 23, and the line impedance value of the loop 21 will be approximately equal to the line impedance value of the loop 22. Therefore, the impedance value of the resistor 51 connected to the loop 21 will be set to be greater than the impedance value of the resistor 52 connected to the loop 22. Thus, the sum of the impedance value of the light-emitting elements 41, the line impedance value, and the impedance value of the resistor 51 on the loop 21 will be approximately equal to the sum of the impedance value of the light-emitting elements 42, the line impedance value, and the impedance value of the resistor 52 on the loop 22. In other words, the total impedance value of the loop 21 will be approximately equal to the total impedance value of the loop 22.

[0071] It should be noted that in this embodiment, the central position of the light-emitting elements refers to the central position of the outermost light-emitting elements in each circuit. For example, the midpoint position of the distance between two light-emitting elements 41 in the light guide area 31, or the midpoint position of the distance between the two outermost light-emitting elements 42 in the light guide area 32. Furthermore, the line length refers to the line length connecting the central positions of multiple light-emitting elements to the converging portion. For example, the line lengths connecting the central positions of two light-emitting elements 41 in the light guide area 31 and the central positions of the two outermost light-emitting elements 42 in the light guide area 32 to the converging portion. Hereinafter, the central position and the line length are both defined in this way.

[0072] Thereby, in this embodiment, the brightness of different light guide areas 31 and 32 in the backlight module 1 can be increased and the light coupling can be made more uniform, reducing the brightness difference between different light guide areas 31 and 32 to a level that cannot be distinguished by the naked eye (for example, the brightness difference is within 50%).

[0073] Figure 5 It is a top view schematic diagram of the light guide plate and the circuit board of the backlight module. As Figure 5 shown, taking the circuits 21 and 25 corresponding to the light guide areas 31 and 34 located in different rows as an example for explanation. When the number of light-emitting elements 41 arranged in the light guide area 31 (for example, two) is equal to the number of light-emitting elements 43 arranged in the light guide area 34 (for example, two), the total impedance value of the light-emitting elements 41 in the circuit 21 will be approximately equal to the total impedance value of the light-emitting elements 43 in the circuit 25. In addition, the line length from the central positions of these light-emitting elements 41 in the circuit 21 to the converging portion 23 is greater than the line length from the central positions of these light-emitting elements 43 in the circuit 25 to the converging portion 23, and the line impedance value of the circuit 21 will be approximately greater than the line impedance value of the circuit 22. Therefore, the impedance value of the resistor 51 connected to the circuit 21 will be less than the impedance value of the resistor 53 connected to the circuit 25. Therefore, the sum of the impedance values of the light-emitting elements 41, the line impedance value, and the impedance value of the resistor 51 on the circuit 21 will be approximately equal to the sum of the impedance values of the light-emitting elements 43, the line impedance value, and the impedance value of the resistor 53 on the circuit 23.

[0074] Thereby, in this embodiment, the brightness of different light guide areas 31 and 34 in the backlight module 1 can be increased and the light coupling can be made more uniform, reducing the brightness difference between different light guide areas 31 and 34 to a level that cannot be distinguished by the naked eye (for example, the brightness difference is within 50%).

[0075] Figure 6 It is a top view schematic diagram of the light guide plate and the circuit board of the backlight module. As Figure 6As shown, taking the circuits 22 and 26 corresponding to the light guide regions 32 and 35 located on different rows as an example for illustration. When the number of light emitting elements 42 (for example, three) provided in the light guide region 32 is equal to the number of light emitting elements 44 (for example, three) provided in the light guide region 35, the total impedance value of the light emitting elements 42 in the circuit 22 will be approximately equal to the total impedance value of the light emitting elements 44 in the circuit 26. Additionally, the total microstructural area of the single-key light guide regions in the light guide region 32 is greater than the total microstructural area of the single-key light guide regions in the light guide region 35. Therefore, the impedance value of the resistor 52 connected to the circuit 22 will be set to be greater than the impedance value of the resistor 54 connected to the circuit 26, so as to enhance the brightness of the light guide region 35. Furthermore, the line length from the central positions of the light emitting elements 42 in the circuit 22 to the converging portion 23 is less than the line length from the central positions of the light emitting elements 44 in the circuit 26 to the converging portion 23, and the line impedance value of the circuit 22 will be approximately greater than the line impedance value of the circuit 26. Therefore, the sum of the line impedance value of the circuit 22 and the impedance value of the resistor 52 is approximately equal to the sum of the line impedance value of the circuit 24 and the impedance value of the resistor 54. That is, the sum of the impedance value of the light emitting elements 42, the line impedance value, and the impedance value of the resistor 52 on the circuit 22 will be approximately equal to the sum of the impedance value of the light emitting elements 44, the line impedance value, and the impedance value of the resistor 54 on the circuit 24.

[0076] Thereby, in this embodiment, the brightness of different light guide regions 32 and 35 in the backlight module 1 can be enhanced and the light coupling can be made more uniform, reducing the brightness difference between different light guide regions 32 and 35 to a level that is indistinguishable to the naked eye (for example, the brightness difference is within 50%).

[0077] Figure 7 It is a top view schematic diagram of the light guide plate and the circuit board of the backlight module. As Figure 7 shown, taking the circuits 21 and 26 corresponding to the light guide regions 31 and 35 located on different rows as an example for illustration. The total microstructural area of the single-key light guide regions in the light guide region 31 is greater than the total microstructural area of the single-key light guide regions in the light guide region 35. Therefore, the number of light emitting elements 41 (for example, two) provided in the light guide region 31 will be less than the number of light emitting elements 44 (for example, three) provided in the light guide region 35. In other words, the ratio of the total microstructural area of the single-key light guide regions in the light guide region 31 divided by the number of light emitting elements 41 on the line segment in the light guide region 31 will be greater than the ratio of the total microstructural area of the single-key light guide regions in the light guide region 35 divided by the number of light emitting elements 44 on the line segment in the light guide region 35. Therefore, the impedance value of the resistor 51 of the circuit 21 can be set to be greater than the impedance value of the resistor 54, so as to enhance the brightness of the light guide region 35.

[0078] Thereby, in this embodiment, the brightness of different light guide regions 31 and 35 in the backlight module 1 can be increased and the light coupling can be made more uniform, so that the brightness difference between different light guide regions 31 and 35 is reduced to a level that cannot be distinguished by the naked eye (for example, the brightness difference is within 50%).

[0079] As described above, the backlight module of the illuminated keyboard in this embodiment divides the keyboard into multiple regions corresponding to the arrangement of the keycaps, divides the light guide plate into multiple light guide regions corresponding to multiple regions, and the circuit board also sets multiple circuits corresponding to multiple regions. Different regions will have different light-emitting areas and different line lengths. The backlight module of this embodiment can set different numbers of light-emitting elements and light guide regions with different micro-structure areas corresponding to different light-emitting areas. Furthermore, the backlight module of this embodiment can set resistors with different impedance values corresponding to different line lengths to make the current in each circuit uniform and stable. In other words, the backlight module of this embodiment adjusts the number of light-emitting elements, the micro-structure area of the light guide region, and the total impedance value of the circuit corresponding to different regions, so as to increase the brightness of the backlight module and make the light coupling more uniform, and reduce the brightness difference between different light guide regions to a level that cannot be distinguished by the naked eye (for example, the brightness difference is within 50%).

[0080] Figure 8 It is a top view schematic diagram of the change states of the light guide plate and the circuit board of the backlight module. As Figure 8 shown, the light-emitting element 41A can also be arranged on one side (for example, the upper side) of the light guide region 31A. For example, the light-emitting element 41A can be arranged on one side of the light guide region 31A adjacent to the long side of the light guide plate. Of course, the micro-structure of the single-key light guide region in the light guide region 31A can also be correspondingly changed in different ways. Thereby, different design methods of the light-emitting elements and the light guide regions can be increased. It should be noted that according to different design requirements, the light-emitting element can also be arranged on the lower side or other different positions of the light guide region.

[0081] To sum up, the backlight module of the illuminated keyboard of the present invention divides the keyboard into multiple regions corresponding to the arrangement of the keycaps, divides the light guide plate into multiple light guide regions corresponding to multiple regions, and the circuit board also sets multiple circuits corresponding to multiple regions. Different regions will have different light-emitting areas and different line lengths. The backlight module of the present invention can set different numbers of light-emitting elements and light guide regions with different micro-structure areas corresponding to different light-emitting areas. Furthermore, the backlight module of the present invention can set resistors with different impedance values corresponding to different line lengths to make the current in each circuit uniform and stable. In other words, the backlight module of the present invention adjusts the number of light-emitting elements, the micro-structure area of the light guide region, and the total impedance value of the circuit corresponding to different regions, so as to increase the brightness of the backlight module and make the light coupling more uniform, and reduce the brightness difference between different light guide regions to a level that cannot be distinguished by the naked eye (for example, the brightness difference is within 50%).

[0082] The components of several embodiments are outlined above, so that those with ordinary knowledge in the technical field to which the present utility model pertains can better understand the concepts of the embodiments of the present utility model. Those with ordinary knowledge in the technical field to which the present utility model pertains should understand that the embodiments of the present utility model can be used as a basis to design or modify other processes and structures to achieve the same purposes and / or obtain the same benefits as those introduced herein. Those with ordinary knowledge in the technical field to which the present utility model pertains should also understand that these equivalent structures do not depart from the spirit and scope of the present utility model, and various changes, substitutions, and other options can be made herein without departing from the spirit and scope of the present utility model. Therefore, the protection scope of the present utility model shall be defined by the scope of the appended patent application.

Claims

1. A backlight module for an luminous keyboard, characterized in that: Include: A circuit board has a first loop, a second loop, a collection portion and a conductive portion, wherein the first loop and the second loop are electrically connected to the collection portion, the collection portion is electrically connected to the conductive portion, the first loop has a first line segment, and the second loop has a second line segment; A light guide plate, disposed above the circuit board, having a first light guide area and a second light guide area, wherein the first light guide area is disposed above the first line segment, and the second light guide area is disposed above the second line segment; A plurality of light emitting elements are arranged in parallel on the first line segment and in parallel on the second line segment; and A resistor unit having a first resistor and a second resistor, wherein the first resistor is disposed in the first loop and the second resistor is disposed in the second loop; The sum of a line impedance value of the first loop and an impedance value of the first resistor is approximately equal to the sum of a line impedance value of the second loop and an impedance value of the second resistor; The conductive part is connected to an external control chip, and the conductive part is used to transmit a control signal.

2. The backlight module according to claim 1, characterized in that: The first light-guiding area includes a first sub-area and a second sub-area that are adjacent to each other, and the first sub-area includes a first single-key light-guiding area and a second single-key light-guiding area that are arranged on both sides thereof. One of the light-emitting elements is arranged on one side of the first single-key light-guiding area and emits a light ray toward the first single-key light-guiding area and the second single-key light-guiding area.

3. The backlight module according to claim 2, characterized in that: The first sub-area has a light-conducting channel, and the light-conducting channel passes through the first single-key light-conducting area or the second single-key light-conducting area.

4. The backlight module according to claim 3, characterized in that: The first sub-area is arranged adjacent to a side edge of the light guide plate, a distance between the first single-key light guide area and the side edge is greater than a distance between the second single-key light guide area and the side edge, and a microstructure density of the first single-key light guide area is less than a microstructure density of the second single-key light guide area.

5. The backlight module according to claim 2, wherein: The light guide plate has a third light guide area, the third light guide area has a third single-key light guide area, the area of ​​the third single-key light guide area is larger than the area of ​​the first single-key light guide area or the area of ​​the second single-key light guide area, and the collecting part is arranged in the area on the circuit board vertically corresponding to the third light guide area.

6. The backlight module according to claim 1, wherein: The number of the light-emitting elements on the first line segment is equal to the number of the light-emitting elements on the second line segment, the line length from the center position of the light-emitting elements in the first loop to the gathering portion is greater than the line length from the center position of the light-emitting elements in the second loop to the gathering portion, and the impedance value of the first resistor is less than the impedance value of the second resistor.

7. The backlight module according to claim 1, wherein: The first light guide area includes multiple single-key light guide areas, and the second light guide area includes multiple single-key light guide areas. A first ratio of the sum of the microstructure areas of the single-key light guide areas in the first light guide area divided by the number of the light-emitting elements on the first circuit segment is greater than a second ratio of the sum of the microstructure areas of the single-key light guide areas in the second light guide area divided by the number of the light-emitting elements on the second circuit segment. The impedance value of the first resistor is greater than the impedance value of the second resistor.

8. The backlight module according to claim 1, wherein: The number of the light-emitting elements on the first line segment is less than the number of the light-emitting elements on the second line segment, the line length from the center position of the light-emitting elements in the first loop to the gathering portion is approximately equal to the line length from the center position of the light-emitting elements in the second loop to the gathering portion, and the impedance value of the first resistor is greater than the impedance value of the second resistor.

9. The backlight module according to claim 1, wherein: The number of the light-emitting elements on the first circuit segment is equal to the number of the light-emitting elements on the second circuit segment, the first light guide area includes multiple single-key light guide areas, the second light guide area includes multiple single-key light guide areas, the sum of the microstructure areas of the single-key light guide areas in the first light guide area is greater than the sum of the microstructure areas of the single-key light guide areas in the second light guide area, and the impedance value of the first resistor is greater than the impedance value of the second resistor.

10. The backlight module according to claim 1, wherein: The first resistor and the second resistor are electrically connected to the collecting portion.

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