Backlight module and display device

Abstract

The present invention relates to a backlight module and a display device. A backlight module and a display device using the backlight module, the structure of the backlight module includes: a back plate having a bottom, which has at least two adjacent edges and the two adjacent edges are connected to form a corner; a plurality of light sources are arranged on the bottom of the back plate; and at least two reflective side walls, which are respectively arranged at the two edges of the back plate, each reflective side wall includes two end sections and a middle section between the two end sections, the end sections correspond to the corners, the middle section corresponds to the non-corner position of the back plate, the middle section forms a first angle with the bottom of the back plate, and the two end sections form a second angle with the bottom of the back plate, and the first angle is greater than the second angle. Thereby, the block scanning uniformity of the backlight module is improved.

Description

Technical Field

[0001] The present invention mainly relates to a light source component, and in particular to a backlight module and a display device. Background Art

[0002] A general direct-type backlight module mainly includes a backplane, several light sources, such as light-emitting diodes (LEDs), and an optical film. The LEDs are arranged in a matrix on the backplane, and the optical film is arranged above the LEDs to mix the light generated by the LEDs.

[0003] In the existing light-emitting diode structure, the light generated by the light-emitting chip is mainly emitted from the top of the chip package, which makes the light intensity from the top of the package higher and the light from the sides of the package weaker. This will form dark areas between adjacent light emitters, and the dark areas formed at the corners or edges are the most obvious, which will cause the appearance of the backlight module to look obvious in light and dark contrast and uneven light mixing. Please refer to Figure 1 As shown, Figure 1 FIG. 1 is a top view of a conventional backlight module 1, which includes a circuit board 11, light emitting diodes 12 arrayed on the circuit board 11, and a frame 13. Figure 1 It can be seen that the light contribution at the center of the matrix LED 12 comes from the front, back, left, and right sides of each LED 12, but at the side close to the frame 13, the light contribution comes only from the left, right, or front and back adjacent LEDs 12. Therefore, the luminous flux per unit area of ​​the block where the edge light source is located is small, so it is easy to form a dark area at the edge. This situation is more serious at the corner of the frame 13, so a dark corner 131 is formed at the corner where the dark areas of the two edges meet, such as Figure 1 In summary, due to the dark corner problem of the conventional backlight module, the light uniformity of the overall display is not good. Summary of the invention

[0004] The object of the present invention is to provide a method of providing an inclined reflective surface with different angles to a back plate in different sections of each reflective side wall of a backlight module, so as to provide different fill-in light effects in different sections.

[0005] To achieve the above-mentioned purpose, the present invention provides a backlight module, comprising: a back panel, comprising a bottom, which has at least two adjacent edges, and the connection between the two adjacent edges forms a corner; a plurality of light sources, arranged at the bottom of the back panel; and at least two reflective side walls, which are respectively arranged at the two edges of the back panel, each reflective side wall includes two end sections and a middle section between the two end sections, the end sections correspond to the corner, the middle section corresponds to the non-corner position of the back panel, the middle section forms a first angle with the bottom of the back panel, the two end sections form a second angle with the bottom of the back panel, and the first angle is greater than the second angle.

[0006] In some embodiments, at least one edge of the back plate may be a straight line or an arc.

[0007] In some embodiments, the two end regions include a first reflection region close to the bottom of the back plate and a second reflection region away from the bottom of the back plate, the first reflection region and the back plate form the second angle, the second reflection region and the back plate form a third angle, the third angle is greater than the second angle, and the first angle is equal to the third angle.

[0008] In some embodiments, the first angle is equal to the third angle.

[0009] In some embodiments, the third angle is 70 degrees.

[0010] In some embodiments, the first angle is 70 degrees to 80 degrees and includes both ends, and the second angle is 45 degrees to 55 degrees and includes both ends.

[0011] In some embodiments, the light source is a light emitting diode matrix, which is composed of a plurality of light emitting diodes arranged in an array, and a spacing between the light emitting diodes is equal to the length of the end segment.

[0012] In some embodiments, a transition section is further included between the middle section and the end section, and the length of the transition section is the spacing between the light-emitting diodes.

[0013] In some embodiments, the LED light source is a large light emitting angle LED.

[0014] Another object of the present invention is to provide a method of providing inclined reflective surfaces with different angles to the back plate in different sections of the reflective side wall of the backlight module, so as to provide different fill-in light effects in different sections.

[0015] To achieve the above object, the present invention provides a display device, comprising the backlight module of the above embodiment and a display panel disposed in front of the backlight module.

[0016] One of the common brightness measurement methods for light-emitting devices is to use a fixed-size square containing several pixels as a brightness measurement block, and move it horizontally in the visible area at intervals of each pixel. The brightness is measured once each time it moves, and the minimum brightness measured above is divided by the maximum brightness as the block scanning uniformity (Area Scan Uniformity, ASU). The common specification of a general light output module is approximately: ASU>85%. The present invention sets two sections of reflection inclination angles on the reflection side wall corresponding to the edge of the light source of the backlight module, which can respectively correspond to the corners and edge areas of the light source backplane with less luminous flux. In accordance with the zone design, the block scanning uniformity can be further improved. Of course, if it is used with a light-emitting diode with a large light-emitting angle, it can have a better effect of improving the block scanning uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A top-down brightness simulation diagram of a conventional backlight module;

[0018] Figure 2 A three-dimensional diagram of a back plate and a reflective side wall of a backlight module according to an embodiment of the present invention;

[0019] Figure 3 for Figure 2 A left side schematic diagram of a front cross-section of a backlight module of an embodiment;

[0020] Figure 4 for Figure 2 A top view of the backlight module of the embodiment;

[0021] Figure 5 A three-dimensional diagram of a back plate and a reflective side wall of a backlight module according to another embodiment of the present invention;

[0022] Figure 6 for Figure 5 The left side schematic diagram of the front cross-sectional view of the backlight module of the embodiment;

[0023] Figure 7 for Figure 6 A schematic diagram of the optical path; and

[0024] Figure 8 It is a front cross-sectional schematic diagram of a display device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail with reference to the drawings as follows. The drawings are mainly simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner. Therefore, only elements related to the present invention are marked in the drawings, and the elements shown are not drawn in terms of the number, shape, size ratio, etc. during implementation. The specifications and dimensions during actual implementation are actually a selective design, and the element layout may be more complicated.

[0026] The following descriptions of the embodiments are with reference to the attached drawings to illustrate specific embodiments in which the present invention may be implemented. The directional terms mentioned in the present invention, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and understand the present invention, rather than to limit the present invention. In addition, in the specification, unless explicitly described to the contrary, the word "comprising" will be understood to mean including the elements described, but not excluding any other elements.

[0027] Please refer to Figure 2 , Figure 3 and Figure 4 The structure of the backlight module 2 of this embodiment includes: a back plate 21, a plurality of light sources 22 and at least two reflective side walls 23, and in this embodiment, there are four reflective side walls. The back plate 21 includes a bottom 211 and at least two adjacent edges 212, and the edges 212 can be straight lines or arcs, and the two adjacent edges 212 form a corner 213 where they are connected to each other.

[0028] The light source 22 is disposed at the bottom 211 of the back plate 21. In this embodiment, the light source 22 is a light emitting diode matrix composed of a plurality of light emitting diodes 221. It is worth mentioning that in order to allow the light emitting diode corners of the light emitting diode matrix to be irradiated with more light, in the embodiment, the main light emitting angle of the light emitting diode 221 is forward light emitting (between negative 60 degrees and 60 degrees), and the remaining oblique large-angle light will be emitted to the reflective side wall and then reflected upward, for example: Lambertian light emitting diodes 221 or light emitting diodes with a larger angle.

[0029] The two adjacent reflective side walls (23a, 23b) are respectively arranged at the bottom 211 of the back plate 21 and close to the edge 212 of the back plate 21 to reflect the light from the light emitting diode 221. The two adjacent reflective side walls (23a, 23b) also correspond to the corner 213 of the back plate 21 at the connection point. In more detail, each reflective side wall (23a, 23b) includes two end sections (24a, 24b) and a middle section 25 located between the two end sections (24a, 24b). The adjacent end sections (24a, 24b) of the two reflective side walls (23a, 23b) correspond to the corner 213. The middle section 25 is correspondingly arranged at a non-corner position of the back plate 21. The middle section 25 forms a first angle α with the bottom 211 of the back plate 21. The two end sections are arranged at a first angle α. The sections (24a, 24b) form a second angle β with the bottom 211 of the back plate 21, and the first angle α and the second angle β are both acute angles. In other words, the angle between the side of the reflective side wall (23a, 23b) facing away from the light source 22 and the back plate 21 is an acute angle; the side of the reflective side wall (23a, 23b) facing the light source is used to reflect light, especially by making the first angle α greater than the second angle β to compensate for the dark angle problem of the corner 213.

[0030] According to the backlight structure of the above embodiment, Figure 2 As shown, the middle section 25 of the reflective side wall 23a corresponds to the edge of the LED matrix, and the corner formed by the end section 24a of the reflective side wall 23a and the end section 24b of the other reflective side wall 23b (usually corresponding to the corner 213 of the back plate 21) corresponds to the corner of the LED matrix. Figure 3 As shown, the reflective side wall 23a can reflect the light emitted by the light emitting diode 221 upwards. Since the second angle β of the end sections (24a, 24b) is smaller than the first angle α of the middle section 25, the end sections (24a, 24b) can receive a larger range of large-angle light emitted by the light emitting diode 221 and reflect it upwards, so as to enhance the brightness of the corner 213 of the back panel 21, thereby achieving the effect of uniform light emission of the overall backlight module. In the present embodiment, the reflective side wall (23a, 23b) further includes a transition section 26, which is located between the end sections (24a, 24b) and the middle section 25, and the angle between the transition section 26 and the back plate 21 is between the first angle α and the second angle β. In addition, the length of the transition section 26 is preferably at least corresponding to the spacing 222 between two adjacent light-emitting diodes 221, so as to mitigate the light source reflection effect in the area and avoid abrupt brightness changes there.

[0031] In another embodiment of the present invention, Figure 5 , Figure 6 The structure of the backlight module 2' of this embodiment is Figure 2 The structural difference of the backlight module 2 in the embodiment is that the two end areas (24a, 24b) include a first reflection area 241a close to the bottom of the back plate 21 and a second reflection area 241b away from the bottom of the back plate, and the first reflection area 241a and the second reflection area 241b of this embodiment are adjacent to each other, the first reflection area 241a and the back plate 21 form the second angle β, and the second reflection area 241b and the back plate 21 form a third angle γ, and the third angle γ is also an acute angle, and the third angle γ is greater than the second angle β. Therefore, the corner positions of the reflective side walls (23a, 23b) of the backlight module 2' in this embodiment provide two kinds of inclined angle reflections for the corner positions of the light-emitting diode matrix, which can more gently enhance the brightness of the corner positions. For more details, please refer to Figure 7 The middle section 25 of the reflective side wall 23a of the present invention utilizes a reflection angle (i.e., the first angle α) to reflect the light of the light emitting diode 221 with a smaller light emitting angle (e.g., Figure 7 The third angle γ can reflect the light of the light emitting diode 221 at a smaller light emitting angle (such as θ1) to the forward direction, thereby compensating for the insufficient brightness of the corresponding middle section 25; and the corresponding end sections (24a, 24b) use two reflection angles to reflect the light. In other words, the third angle γ can make the light emitting diode 221 have a smaller light emitting angle (such as Figure 7 In addition to reflecting the light θ1) in the forward direction, the second angle β can also make the light output angle larger (such as Figure 7 The light of θ2) is reflected in the forward direction. The end sections of the reflective side walls (23a, 23b) of the present invention have two angles for reflecting light, which can compensate more light to the corners of the LED matrix than the middle section 25 having only one reflection angle. In summary, the backlight module of the present invention has better light uniformity.

[0032] The foregoing Figure 2 In the embodiment, the first angle of the present invention can be 70 degrees to 80 degrees (including both ends), and the second angle can be 45 degrees to 55 degrees (including both ends). Figure 5 The third angle added in the embodiment can be 70 degrees. Figure 6 In the embodiment, the third angle γ and the first angle α are the same angle value.

[0033] like Figure 4As shown. The purpose of setting the end sections (24a, 24b) of this embodiment is to provide more light to be reflected upwards corresponding to the darkest part of the corner of the LED matrix. In particular, the length of the end sections (24a, 24b) should be between 0.5 and 3 times the distance between two adjacent LEDs 221. It should be particularly noted that if the length of the end regions (24a, 24b) is too long, for example, more than 3 times, it may cause the brightness of the LED matrix corresponding to the middle region 25 to be excessive, resulting in a decrease in the overall luminous uniformity.

[0034] like Figure 8 The display device 4 of the embodiment of the present invention comprises the aforementioned backlight module (2, 2'), and a display panel 3 ( Figure 8 Taking the backlight module 2 as an example, the display device 4 also has the effect of good light uniformity, which will not be elaborated here.

[0035] From the above embodiments, it can be seen that the present invention sets at least two sections with different reflection inclination angles on the reflective side wall corresponding to the edge of the light-emitting diode matrix of the backlight module, which respectively correspond to the dark corners and edge areas of the backplane with lower brightness, and can produce a better brightness enhancement effect on the darker corners, so as to obtain better light uniformity of the overall backlight module.

[0036] The above disclosed embodiments are only illustrative of the principles, features and effects of the present invention, and are not intended to limit the scope of the present invention. Any person skilled in the art may modify and alter the above embodiments without violating the spirit and scope of the present invention. Any equivalent changes and modifications made using the contents disclosed in the present invention shall still be covered by the attached claims.

[0037] [List of Reference Numerals]

[0038] 1: Backlight module

[0039] 11: Circuit Board

[0040] 13: Frame

[0041] 131: Vignette

[0042] 14: Optical film

[0043] 2. 2': Backlight module

[0044] 21: Back panel

[0045] 211: Bottom

[0046] 212: Edge

[0047] 213: Corner

[0048] 22: Light Source

[0049] 221: Light Emitting Diode

[0050] 222: Spacing

[0051] 23a, 23b: Reflective side walls

[0052] 24a, 24b: End sections

[0053] 241a: First reflection area

[0054] 241b: Second reflection area

[0055] 25: Middle section

[0056] 26: Transition section

[0057] 3: Display Panel

[0058] 4: Display device

[0059] α: first angle

[0060] β: Second angle

[0061] γ: The third angle.

Claims

1. A backlight module, characterized in that: Include: A back plate, comprising a bottom, having at least two adjacent edges, wherein a corner is formed at a position where the two adjacent edges are connected; A plurality of light sources are arranged on the bottom of the back plate; as well as At least two reflective side walls are respectively arranged at the two edges of the back plate, each reflective side wall includes two end sections and a middle section between the two end sections, the end sections correspond to the corners, the middle section corresponds to the non-corner position of the back plate, the side of the middle section facing away from the light source forms a first angle with the bottom of the back plate, the sides of the two end sections facing away from the light source form a second angle with the bottom of the back plate, the first angle is greater than the second angle, and both the first angle and the second angle are acute angles, the first angle is 70 degrees to 80 degrees and includes both end values, and the second angle is 45 degrees to 55 degrees and includes both end values.

2. The backlight module according to claim 1, characterized in that: At least one edge of the back plate is a straight line.

3. The backlight module according to claim 1 or 2, characterized in that: At least one edge of the back plate is an arc line.

4. The backlight module according to claim 1, wherein: The two end areas include a first reflection area close to the bottom of the back plate and a second reflection area away from the bottom of the back plate, the first reflection area forms the second angle with the back plate, the second reflection area forms a third angle with the back plate, the third angle is greater than the second angle, and the third angle is an acute angle.

5. The backlight module according to claim 4, characterized in that: The first angle is equal to the third angle.

6. The backlight module according to claim 4, characterized in that: The third angle is 70 degrees.

7. The backlight module according to claim 1, wherein: The light source is a light emitting diode matrix, which is composed of a plurality of light emitting diodes arranged in an array, and the spacing between the light emitting diodes is equal to the length of the end section.

8. The backlight module according to claim 7, characterized in that: A transition section is also included between the middle section and the end section, and the length of the transition section is the spacing between the light-emitting diodes.

9. The backlight module according to claim 7, wherein: The light emitting diode is a light emitting diode with a large light emitting angle.

10. A display device, comprising: The backlight module according to any one of claims 1 to 9; and Display panel, It is arranged in front of the backlight module.

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