TWI716041B - Back light module - Google Patents

Abstract

A back light module includes a light guide plate that has a first side and a second side, a light emitting element, and a light guiding element. The light emitting element is adjacent to the first side of the light guide plate. The light guiding module is disposed between the first side and the second side, and the light guiding module forms a first opening. The light guiding element includes a first refractive portion and a second refractive portion. The first refractive portion has a first refractive index. The second refractive portion has a second refractive index. The first refractive index and the second refractive index is different from a refractive index of the light guide plate. An orthogonal projection of the first refractive portion on the first side is not overlapped with an orthogonal projection of the second refractive portion on the first side.

Description

Backlight module

This disclosure relates to a backlight module.

In current handheld electronic devices, various functional components are buried in the upper frame and the lower frame area. At present, some electronic devices cancel the design of the upper frame and place the front lens in the center of the display area in pursuit of a higher screen-to-body ratio. However, in this case, holes must be made in the display module and the backlight module in the display area, and this design easily leads to the problem of uneven brightness near the holes in the display area. Therefore, how to solve the above problems is one of the important issues in this field.

This disclosure relates to a backlight module. The backlight module includes a light guide plate, a light emitting element, and a light guide element. The light guide plate has a first side and a second side. The light emitting element is close to the first side of the light guide plate. The light guide element is arranged between the first side and the second side and forms a first opening. The light guide element includes a first refraction portion and a second refraction portion. The first refractive part has a first refractive index, and the second refractive part has a second refractive index, wherein the first refractive index and the second refractive index are different from the refractive index of the light guide plate. The orthographic projection of the first refractive part on the first side and the second refractive part on the first side The orthographic projections do not overlap each other.

In summary, the backlight module proposed in the present disclosure can guide the light emitted by the light-emitting element on the first side to the end of the first opening close to the second side, thereby preventing the backlight module from being provided with the first opening. As a result, the light intensity cannot be evenly distributed.

10‧‧‧Electronic device

10a‧‧‧First surface

11‧‧‧Photographic Module

12‧‧‧Cover glass

13‧‧‧Filter layer

14‧‧‧Liquid crystal layer

15‧‧‧Voltage control layer

16‧‧‧Backlight Module

16a‧‧‧First side

16b‧‧‧Second side

161‧‧‧Light-emitting element

162‧‧‧Light guide element

163‧‧‧Reflective film

164‧‧‧Light guide plate

165‧‧‧Diffusion film

17‧‧‧Back cover module

50, 60, 70, 80, 90, 100, 110‧‧‧Light guide element

51, 61, 71, 81, 91, 101, 111‧‧‧First refraction part

51a, 51b, 51c, 52a, 52c, 53a, 61a, 61c, 62a, 62c, 71a, 71c, 72a, 72c, 81a, 82a, 101a, 101c, 102a, 102c

52, 62, 72, 82, 92, 102, 112‧‧‧Second refracting part

53, 63, 73, 83, 93, 103, 113‧‧‧third refracting part

54, 64, 74, 84, 94, 104, 114‧‧‧Fourth refracting part

95, 105, 115‧‧‧reflective ring

106、116‧‧‧First reflection part

107、117‧‧‧Second reflection part

106a, 106b, 107a, 107b, 116a, 116b, 117a, 117b‧‧‧reflecting surface

1111, 1121‧‧‧First refractive layer

1112、1122‧‧‧Second refractive layer

1113、1123‧‧‧The third refractive layer

2-2, 4-4‧‧‧ line segment

a1, a2, a3, a4‧‧‧angle

d‧‧‧Distance

DA‧‧‧Display area

L‧‧‧Light

O1‧‧‧First opening

O2‧‧‧Second opening

PA‧‧‧Frame area

R‧‧‧Radius

r1‧‧‧Inner diameter

r2‧‧‧Outer diameter

t1, t2, t3‧‧‧thickness

x1, x2‧‧‧horizontal axis

y‧‧‧Vertical axis

FIG. 1 is a front view of an electronic device according to an embodiment of the disclosure.

Figure 2 shows a cross-sectional view along line 2-2 in Figure 1.

FIG. 3 is a front view of the backlight module in the electronic device according to the embodiment of FIG. 1. FIG.

Figure 4 shows a cross-sectional view along line 4-4 in Figure 3.

FIG. 5 is a top view of a light guide element according to an embodiment of the present disclosure.

FIG. 6 is a top view of a light guide element according to another embodiment of the present disclosure.

FIG. 7 is a top view of a light guide element according to another embodiment of the present disclosure.

FIG. 8 is a top view of a light guide element according to another embodiment of the present disclosure.

FIG. 9 is a top view of a light guide element according to another embodiment of the present disclosure.

FIG. 10 is a top view of a light guide element according to another embodiment of the present disclosure.

FIG. 11 is a top view of a light guide element according to another embodiment of the present disclosure.

Hereinafter, multiple embodiments of the present invention will be disclosed in the form of drawings. For clear description, 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 the present invention. That is, in some embodiments of the present invention, these practical details are unnecessary. In addition, in order to simplify the drawings, some conventionally used structures and elements will be shown in a simple schematic manner in the drawings. Moreover, unless otherwise indicated, the same component symbols in different drawings can be regarded as corresponding components. The drawing of these drawings is to clearly express the connection relationship between the elements in these embodiments, and does not show the actual size of each element.

Please refer to FIG. 1, which shows a front view of an electronic device 10 according to an embodiment of the present disclosure. Taking this embodiment as an example, the electronic device 10 is a mobile phone with a display function and a camera function. As shown in FIG. 1, the first surface 10a of the electronic device 10 has a display area DA and a frame area PA. The display area DA can display a color image, and a first opening O1 is opened in the display area DA.

As shown in FIG. 1, the electronic device 10 further includes a camera module 11. The photographing module 11 is disposed in the first opening O1. In this embodiment, the photographing module 11 may include a charged coupled device (CCD) whose lens faces the first surface 10a, thereby allowing the electronic device 10 to capture external images facing the first surface 10a.

Next, please refer to Figure 2, which shows a cross-sectional view along line 2-2 in Figure 1. As shown in FIG. 2, the electronic device 10 further includes a cover glass 12, a display module (including a filter layer 13, a liquid crystal layer 14 and a voltage control layer 15 ), a backlight module 16 and a back cover module 17.

As shown in Figure 2, the cover glass 12 can be made of glass, acrylic or other types of transparent materials. The cover glass 12 forms the first surface 10 a of the electronic device 10. The cover glass 12 can protect the internal components of the electronic device 10 and prevent the external environment from damaging the internal components of the electronic device 10.

As shown in FIG. 2, the display module in this embodiment is a liquid crystal display (LCD) module, in which the filter layer 13 includes a color filter. For example, in this embodiment, the filter layer 13 includes a red filter layer, a blue filter layer, and a green filter layer. Different color filter layers allow different wavelengths of light to pass through. The filter layer of each color defines a sub-pixel, and multiple sub-pixels define a pixel unit.

As shown in FIG. 2, a liquid crystal layer 14 and a voltage control layer 15 are provided between the filter layer 13 and the backlight module 16. The liquid crystal layer 14 contains liquid crystal molecules. The voltage control layer 15 includes sub-pixel electrodes, thin film transistors (TFT), data lines, and scan lines. Each sub-pixel electrode corresponds to a thin film transistor, and each thin film transistor corresponds to a sub pixel, and each group of data lines and scan lines corresponds to a thin film transistor. The external controller can individually control the switch of each thin film transistor through the data line and the scan line. According to the switching of the thin film transistor, the sub-pixel electrodes apply voltages of different degrees to the liquid crystal molecules in the liquid crystal layer 14 to change the tilt angle of the liquid crystal molecules, thereby controlling the light transmittance in each sub-pixel.

The backlight module 16 can provide light traveling toward the first surface 10a. The light sequentially passes through the voltage control layer 15, the liquid crystal layer 14 and the filter layer 13 above the backlight module 16. As mentioned above, the voltage control layer 15 and the liquid crystal layer 14 control the transmittance of light in different sub-pixels, and then the light is converted into colored light of different colors through the filter layer 13. In this way, the electronic device 10 can display a colorful image through the filter layer 13, the liquid crystal layer 14, the voltage control layer 15, and the backlight module 16.

As shown in FIG. 2, the back cover module 17 may contain various components with different functions, such as a processor, a battery, a radio device or a playback device, and so on. The present disclosure is not limited to the above, and therefore, the above components are not explicitly shown in Figure 2. In this embodiment, the camera module 11 is disposed on the back cover module 17 and protrudes toward the first surface 10a.

As shown in FIG. 2, the first opening O1 of the electronic device 10 is located in the filter layer 13, the liquid crystal layer 14, the voltage control layer 15 and the backlight module 16. The first opening O1 penetrates through the filter layer 13, the liquid crystal layer 14, the voltage control layer 15 and the backlight module 16, so that the camera module 11 can be accommodated in the first opening O1. With the above design, the photographing module 11 of the electronic device 10 can be located inside the display area DA (see FIG. 1), so that the display area DA can extend and surround the photographing module 11, increasing the area of the display area DA.

Please refer to Figure 3 and Figure 4 next. FIG. 3 is a front view of the backlight module 16 in the electronic device 10 according to the embodiment of FIG. 1. Figure 4 shows a cross-sectional view along line 4-4 in Figure 3. The light guide plate 164 has a first side 16a and a second side 16b opposite to the first side 16a, and the first opening O1 is provided between the first side 16a and the second side 16b.

As shown in FIG. 4, in this embodiment, the backlight module 16 includes a light emitting element 161, a light guide element 162, a reflective film (reflective film) 163, a light guide plate (LGP) 164, and a diffusion film (diffusion film). film)165. The light emitting element 161 is close to the first side 16 a of the light guide plate 164. The light guide element 162 is closer to the second side 16b of the backlight module 16 and forms a first opening O1. That is, the distance from the light guide element 162 to the second side 16b is smaller than the distance from the light guide element 162 to the first side 16a. The light guide plate 164 is disposed between the reflective film 163 and the diffusion film 165, wherein the diffusion film 165 is closer to the first surface 10a of the electronic device 10 (refer to FIG. 1).

As shown in FIG. 4, the light-emitting element 161 can be a light emitting diode (LED) or other elements that can generate light. The light-emitting element 161 is configured to emit light toward the second side 16 b of the light guide plate 164. The light will change its traveling direction after being guided by the reflective film 163 and the light guide plate 164, and finally pass through the diffuser film 165 and leave the backlight module 16. Specifically, the backlight module 16 in this embodiment is an edge type, that is, the light-emitting element 161 is located on one of the sides of the display area DA of the electronic device 10 (refer to FIG. 1 at the same time).

As shown in FIG. 4, part of the light emitted by the light emitting element 161 will reach the first opening O1. The light guide element 162 is configured to guide light to the end of the first opening O1 close to the second side 16b. In this way, it can be ensured that the light emitted by the light-emitting element 161 can uniformly reach the space near the second side 16b of the light guide plate 164 without spilling out through the first opening O1. In this embodiment, the light guide element 162 is detachably disposed in the backlight module 16. That is, as shown in FIG. 4, the backlight module 16 has a second opening O2, and the light guide element 162 is detachably disposed inside the second opening O2. As shown in Figure 4, the first opening O1 It has an inner diameter r1, and the second opening O2 has an outer diameter r2, wherein the inner diameter r1 is smaller than the outer diameter r2. Next, various implementations of the detachable light guide element 162 will be described with reference to FIGS. 5-11. However, it should be understood that people in the field can make changes based on practical needs and are not limited to those shown in Figures 5-11.

Please refer to FIG. 5, which shows a top view of a light guide element 50 according to an embodiment of the present disclosure. In this embodiment, the light guide element 50 is actually the light guide element 162 in Figures 3 and 4. Therefore, the description of Figure 5 below can also refer to Figures 3 and 4 at the same time. .

As shown in FIG. 5, the light guide element 50 has a ring shape as a whole, and a first opening O1 is formed in the center. Specifically, the light guide element 50 has an inner diameter r1 and an outer diameter r2. The inner diameter r1 defines the size of the first opening O1, and the outer diameter r2 defines the size of the second opening O2 (refer to FIG. 4 at the same time). It should be understood that the dimensions of the components in Figure 5 are not shown to scale. In some embodiments, the distance between the outer edge of the light guide element 50 and the first opening O1 is d, the radius of the first opening O1 is R, and satisfies d≦R/10, so as to achieve better light transmission effect.

As shown in Figure 5, the light guide element 50 includes a first refraction portion 51 and a second refraction portion 52, wherein the orthographic projections of the first refraction portion 51 and the second refraction portion 52 on the first side 16a of the light guide plate 164 are mutually Does not overlap. The first refraction portion 51 and the second refraction portion 52 may be made of a transparent refraction material. For example, the first refraction portion 51 and the second refraction portion 52 can be made of a blended resin. The first refractive part 51 has a first refractive index n1, and the second refractive part 52 has a second refractive index n2. In this embodiment, the first refraction portion 51 and the second refraction portion 52 are made of the same material, so the first refractive index n1 is equal to the second refractive index n2.

As shown in Figure 5, the light guide element 50 further includes a third refraction portion 53 And the fourth refraction part 54. The third refraction portion 53 and the fourth refraction portion 54 are connected to the first refraction portion 51 and the second refraction portion 52, and the third refraction portion 53 is closer to the first side 16 a than the fourth refraction portion 54. The third refraction portion 53 and the fourth refraction portion 54 may be made of transparent refraction materials. In the present embodiment, the third refraction portion 53 has a third refractive index n3, and the fourth refraction portion 54 has a fourth refractive index n4. In this embodiment, the third refraction portion 53 and the fourth refraction portion 54 can be made of the same material, so the third refractive index n3 is the same as the fourth refractive index n4. More specifically, the third refractive index n3 and the fourth refractive index n4 are equal to the refractive index of the light guide plate 164 in FIG. 4.

Referring to FIGS. 3 and 5 at the same time, it can be understood that the third refraction portion 53 is closer to the light-emitting element 161. Therefore, the light L emitted by the light-emitting element 161 first passes through the light guide plate 164 and then enters the third refraction portion 53. In this embodiment, since the refractive index of the light guide plate 164 and the third refraction portion 53 are the same, the light L will not be deflected after passing through the interface 53 a of the light guide plate 164 and the third refraction portion 53.

Thereafter, as shown in Figure 5, the light L will pass through the interface 51a between the third refraction portion 53 and the first refraction portion 51 (or the interface 52a between the third refraction portion 53 and the second refraction portion 52) . In this embodiment, the first refractive index n1 of the first refractive part 51 is greater than the third refractive index n3 of the third refractive part 53. Due to the above-mentioned difference in refractive index, the first refracting part 51 will guide the light L to deflect it.

Then, as shown in FIG. 5, after leaving the interface 51 a between the first refraction portion 51 and the second refraction portion 52, the light L enters the interface 51 b between the first refraction portion 51 and the light guide plate 164. Since the incident angle of the light L on the interface 51b is smaller than the total reflection angle of the interface 51b, the light L will be reflected and deviate toward the first opening O1.

Finally, as shown in FIG. 5, the light L shifted toward the first opening O1 enters the interface 51c between the first refraction portion 51 and the fourth refraction portion 54. In this embodiment, the first refractive index n1 of the first refractive part 51 is greater than the fourth refractive index n4 of the fourth refractive part 54. Due to the aforementioned difference between the refractive indices, the fourth refraction portion 54 will guide the light L to be away from the first opening O1.

As shown in FIG. 5, the light L entering the light guide element 50 from the front of the first opening O1 is guided to the rear of the first opening O1 and travels toward the second side 16b, and the exit direction is close to the incident direction. In other words, the light guide element 50 can uniformly distribute the light L to an area close to the second side 16b of the light guide plate 164 (refer to FIG. 3). In this way, the brightness uniformity of the display area DA (see FIG. 1) of the electronic device 10 can be ensured.

As shown in FIG. 5, the horizontal axis x1 at the junction of the interface 51a and the first opening O1 is parallel to the first side 16a, and the interface 51a and the horizontal axis x1 have an angle a1. Approximately, the horizontal axis x2 at the junction of the interface 51c and the first opening O1 is parallel to the first side 16a and the second side 16b, and the interface 51c and the horizontal axis x2 have an angle a2. In this embodiment, the interface 51a is located below the horizontal axis x1, and the interface 51c is located above the horizontal axis x2. That is to say, the angle a1 and the angle a2 are opposite in direction, but the value is the same (the difference is only a negative sign).

Different angles a1 and a2 will affect the degree of deflection of the light L. Specifically, the incident angle to the interface 51b should be smaller than the total reflection angle of the interface 51b, so that the light L can reach the fourth refracting portion 54. The angle a1 of the interface 51a and the angle a2 of the interface 51c will affect the degree of deflection of the light L. Those skilled in the art can adjust the angle a1 and the angle a2 according to practical needs, so that the largest proportion of the light L can be successfully reflected by the interface 51c to the fourth refraction部54.

For example, please refer to FIG. 6 which shows a top view of a light guide element 60 according to another embodiment of the present disclosure. As shown in FIG. 6, the light guide element 60 is the same as the light guide element 50 as a whole, and the difference lies in the inclination angles of the interface 61a and the interface 61c of the light guide element 60. Specifically, in Figure 6, the interface 61a is horizontal to the horizontal axis x1, and the interface 61c is parallel to the horizontal axis x2. That is, in this embodiment, the angle a1 and the angle a2 are both equal to zero.

Alternatively, refer to FIG. 7, which shows a top view of a light guide element 70 according to another embodiment of the present disclosure. As shown in FIG. 7, the light guide element 70 is the same as the light guide element 50 as a whole, and the difference is that the inclination angles of the interface 71 a and the interface 71 c of the light guide element 70 are different. In this embodiment, the interface 71a is located above the horizontal axis x1, and the interface 71c is located below the horizontal axis x2. In other words, the signs of the angle a1 and the angle a2 in this embodiment are opposite to those shown in FIG. 5.

Next, please refer to FIG. 8, which shows a top view of a light guide element 80 according to another embodiment of the present disclosure. As shown in FIG. 8, the light guide element 80 is the same as the light guide element 50 as a whole, and the difference is that the first refraction portion 81, the second refraction portion 82, and the fourth refraction portion 84 in the light guide element 80 are merged with each other. That is, in this embodiment, the first refraction portion 51, the second refraction portion 52, and the fourth refraction portion 54 are made of the same material, and the three are integrally formed, so that the first refraction portion 81 and the second refraction portion 82 and the fourth refraction portion 84 are combined into a C-shaped refraction portion. In this embodiment, light can be guided to the fourth refracting portion 84 behind the first opening O1 through the interface 81a. In addition, changing the rear of the first opening O1 to a C-shaped design has the advantage of convenient manufacturing.

Next, please refer to Figure 9, which shows another example based on this disclosure The top view of the light guide element 90 of the embodiment. The light guide element 90 is the same as the light guide element 50 as a whole, and the difference is that the light guide element 90 further includes a reflection ring 95.

As shown in Figure 9, the reflective ring 95 is located at the center of the light guide element 90 and surrounds the first opening O1. The reflection ring 95 may be disposed on the inner surface of the first opening O1. Specifically, the reflection ring 95 may be a reflective metal ring or a ring structure made of other total reflection materials. By setting the reflection ring 95 around the first opening O1, it is possible to prevent part of the light L that is not guided by the first refraction portion 91 from directly entering the first opening O1. In this way, it can be ensured that the camera module 11 (see Figure 2) located in the first opening O1 is not interfered by light. In addition, the reflection ring 95 can also be provided in the embodiment in FIG. 7, and the embodiment in FIG. 7 requires the reflection ring 95 to be installed in comparison with the embodiment in FIG. 5.

Next, please refer to FIG. 10, which shows a top view of a light guide element 100 according to another embodiment of the present disclosure. As shown in FIG. 10, the light guide element 100 is similar to the light guide element 90, and the difference is that the light guide element 100 further includes a first reflecting portion 106 and a second reflecting portion 107, and the angle a1 and the angle a2 are slightly different. In this embodiment, the reflection ring 105 may not be present at the same time, that is, it may be omitted. In this way, the first reflection part 106 can be directly connected to the first opening O1.

As shown in FIG. 10, the first reflective portion 106 and the second reflective portion 107 can be made of metal or various reflective materials. The first reflective portion 106 and the second reflective portion 107 are respectively disposed in the third refraction portion 103 and the fourth refraction portion 104, and are respectively interposed between the first refraction portion 101 and the second refraction portion 102. In this embodiment, the first reflecting portion 106 has a reflecting surface 106a and a reflecting surface 106b. The reflective surface 106a is connected to the interface 101a, and the reflective surface 106b is connected to the interface 52a. Similarly, the second reflection portion 107 has a reflection surface 107a and a reflection surface 107b. The reflective surface 107a is connected to the interface 101c, and the reflective surface 107b is connected to the interface 102c.

As shown in FIG. 10, by providing the first reflecting part 106 in the third refraction part 103, the light L incident on the interface 101a and the interface 102a can be guided by the reflecting surface 106a or the reflecting surface 106b to enter the interface 101a or Interface 102a. The subsequent progress of the light L is similar to that shown in Figure 5, and the description will not be repeated here.

As shown in FIG. 10, the third refraction portion 103 and the fourth refraction portion 104 in this embodiment are substantially the same. The second reflective portion 107 is provided in the fourth refraction portion 104, so that the light L emitted from the interface 101b and the interface 102b can be guided by the reflective surface 107a or the reflective surface 107b and leave the light guide element 100 in a uniform direction. In summary, by designing the first reflecting portion 106 and the second reflecting portion 107 in the light guide element 100, more light L can be transmitted to the side of the first opening O1 close to the second side 16b. In order to improve the brightness uniformity in the display area DA of the electronic device 10 (refer to FIG. 1 and FIG. 3 at the same time).

As shown in FIG. 10, the reflecting surface 106a and the vertical axis y have an angle a3, and the reflecting surface 106b and the vertical axis y also have an angle a3, but the direction is opposite. In this embodiment, the angle a3 and the first refractive index n ₁₀₁ of the first refraction portion ₁₀₁ and the third refractive index n _{103 of the} third refraction portion 103 satisfy the following mathematical relationship (1):

For example, in one embodiment, the first refractive index n _{101 of the} first refraction portion 101 is between 1.51 and 2.10, and the third refractive index n ₁₀₃ of the third refraction portion ₁₀₃ is 1.5, and the angle a3 is Between 12 degrees and 83 degrees. As shown in FIG. 10, the angle between the reflecting surface 106a and the reflecting surface 106b is twice the angle a3, that is, the angle between the two reflecting surfaces is approximately between 24 degrees and 166 degrees.

As shown in Fig. 11, the second reflecting portion 107 and the first reflecting portion 106 in this embodiment are disposed on opposite sides of the first opening O1, and exhibit a symmetrical design. It should be understood that the reflecting surface 106a, the reflecting surface 106b, The inclination of the reflective surface 107a and the reflective surface 107b can be adjusted according to practical requirements, and is not limited to the one shown in FIG. 10.

Finally, please refer to FIG. 11, which shows a top view of a light guide element 110 according to another embodiment of the present disclosure. As shown in FIG. 11, the light guide element 110 is similar to the light guide element 100, but the difference is that the first refraction portion 111 and the second refraction portion 112 in the light guide element 110 each include a plurality of refraction layers.

As shown in FIG. 11, the first refraction portion 111 includes a first refraction layer 1111, a second refraction layer 1112, and a third refraction layer 1113. The first refraction layer 1111, the second refraction layer 1112, and the third refraction layer 1113 are sequentially arranged in a direction away from the first opening O1. The first refractive layer 1111 is adjacent to the reflection ring 115. The second refractive layer 1112 surrounds the first refractive layer 1111. The third refractive layer 1113 surrounds the second refractive layer 1112. In this embodiment, the first refraction layer 1111, the second refraction layer 1112, and the third refraction layer 1113 can be made of a transparent refraction material, so that the first refraction layer 1111 has a refractive index n11, and the second refraction layer 1112 has a refractive index n12. The third refractive layer 1113 has a refractive index n13.

Similarly, the second refraction portion 112 includes a first refraction layer 1121, a second refraction layer 1122, and a third refraction layer 1123. Adjacent to the first refractive layer 1121 Reflection ring 115. The second refractive layer 1122 surrounds the first refractive layer 1121. The third refractive layer 1123 surrounds the second refractive layer 1122. In this embodiment, the first refraction layer 1121, the second refraction layer 1122, and the third refraction layer 1123 can be made of a transparent refraction material, so that the first refraction layer 1121 has a refractive index n11, and the second refraction layer 1122 has a refractive index n12. The third refractive layer 1123 has a refractive index n13. That is, in this embodiment, the second refraction portion 112 and the first refraction portion 111 are mirror-symmetrical to each other.

In this embodiment, the refractive index n12 is greater than the refractive index n13, and the refractive index n13 is greater than the refractive index n11. In other words, the first refractive layer 1111, the second refractive layer 1112, and the third refractive layer 1113 have different refractive indexes. In this embodiment, the refractive index n11, refractive index n12, and refractive index n13 are all greater than the third refractive index n3 of the third refraction portion 113. Therefore, when the light L enters the first refraction portion 111, it will occur at the interface 111a. Deflection, and the degree of deflection will vary depending on where the light L enters.

Specifically, the greater the difference in refractive index between two adjacent media, the greater the degree of deflection. Therefore, by appropriately adjusting the refractive indices of the first refraction layer 1111, the second refraction layer 1112, and the third refraction layer 1113, the amount of deflection of the light L incident from different angles can be adjusted more accurately, so that most All the light L can be transmitted to the fourth refracting part 114.

In addition, as shown in FIG. 11, since the first refraction layer 1111, the second refraction layer 1112, and the third refraction layer 1113 have different refractive indexes from each other, except for the interface 111b between the third refraction layer 1113 and the external medium , There is an interface 111c between the third refraction layer 1113 and the second refraction layer 1112 inside the first refraction portion 111, and there is an interface 111c between the second refraction layer 1112 and the first refraction layer 1111 It also has an interface 111d. The interface 111b, the interface 111c, and the interface 111d may have the same or different total reflection angles. Since there are multiple interfaces in the first refraction part 111, when the light L travels in the first refraction part 111, there is more opportunity for total reflection to reach the fourth refraction part 114 behind the first opening O1.

In this embodiment, since the first refraction portion 111 has multiple interfaces, the light L can be effectively confined in the first refraction portion 111. Since the second refractive layer 1112 has a relatively large refractive index n12, further speaking, most of the light L will be confined in the second refractive layer 1112. In this way, after most of the light L enters the first refracting part 111 through the interface 111a, it will not leave the interface 111b or enter the reflection ring 115, but will leave the first refracting part 111 through the interface 111e. Therefore, in some embodiments, the reflective ring 115 can be removed, and still have a good light guiding effect. In the embodiment in which the reflection ring 115 is removed, the refractive index n11 of the first refraction layer 1111, the refractive index n12 of the second refraction layer 1112, and the refractive index n13 of the third refraction layer 1113 may be greater than those in the first opening O1. The refractive index of _air n _air (approximately equal to 1), so as to further ensure that the light L does not enter the first opening O1.

In this embodiment, the first refraction part 111 includes three refraction layers. However, in some embodiments, the first refraction portion 111 may include two, four, or more refraction layers. For example, the first refraction portion 111 in Figure 11 may only include the first refraction layer 1111 and the second refraction layer 1112, and the refractive index n11 is smaller than the refractive index n12, which can also prevent the light L from entering the first opening O1 .

As shown in FIG. 11, the vertical axis y at the junction of the reflecting surface 116a and the reflecting surface 116b is perpendicular to the first side 16a and the second side 16b. The reflective surface 116a and the vertical axis y sandwich an angle a4, and the reflective surface 116b and the vertical axis y also sandwich an angle a4, but the direction is opposite. In the present embodiment, the angle a4 n the refractive index of the second refractive layer 1112 satisfies the following mathematical relationship (2) between the n-refractive index and the third refractive layer _{1113 1112} 1113:

As shown in FIG. 11, the second reflective portion 117 and the first reflective portion 116 in this embodiment are disposed on opposite sides of the first opening O1, and exhibit a symmetrical design. It should be understood that the inclination of the reflective surface 116a, the reflective surface 116b, the reflective surface 117a, and the reflective surface 117b can be adjusted according to practical requirements, and is not limited to those shown in FIG. 11.

As shown in FIG. 11, in this embodiment, the first refraction layer 1111, the second refraction layer 1112, and the third refraction layer 1113 are all arcs, and the three are concentric circles with each other. The first refractive layer 1111 has a thickness t1, the second refractive layer 1112 has a thickness t2, and the third refractive layer 1113 has a thickness t3.

Specifically, the thickness t1 refers to the difference between the radius of curvature of the surface of the first refractive layer 1111 close to the reflection ring 115 and the radius of curvature of the surface of the first refractive layer 1111 away from the reflection ring 115. The thickness t2 refers to the difference between the radius of curvature of the surface of the second refractive layer 1112 close to the reflection ring 115 and the radius of curvature of the surface of the second refractive layer 1112 away from the reflection ring 115. The thickness t3 refers to the difference between the radius of curvature of the surface of the third refraction layer 1113 close to the reflection ring 115 and the radius of curvature of the surface of the third refraction layer 1113 away from the reflection ring 115. In this embodiment, the total of the thickness t1, the thickness t2, and the thickness t3 may be less than 5% of the inner diameter r1 of the first opening O1. Should understand, The drawings are not drawn to actual scale for the sake of explanation.

The various embodiments of the light guide element 162 in Figure 4 have been described above with reference to Figures 5 to 11. In other words, the user can install the light guide elements 50 to 110 shown in FIG. 5 to FIG. 11 into the backlight module 16 in FIG. 4. However, in some embodiments, the light guide element 162 can be integrally formed with the light guide plate 164.

Here, the light guide element 50 depicted in FIG. 5 is taken as an example. The refractive index of the third refraction portion 53 and the fourth refraction portion 54 of the light guide element 50 is the same as the refractive index of the light guide plate 164, so actually the third refraction portion 53, the fourth refraction portion 54 and the light guide plate 164 can be made of the same material Manufactured in one piece. In such an embodiment, the first refraction portion 51 and the second refraction portion 52 are provided on the light guide plate 164. Similarly, the first refraction portions 61-111 and/or the second refraction portions 62-112 in the light guide elements 60-110 in FIGS. 6-11 and the light guide plate 164 may be integrally formed of the same material. To make it out.

In summary, the electronic device proposed in the present disclosure has an opening located in the display area, and a camera module is arranged in the opening. This design reduces the area of the frame area required by the electronic device and correspondingly increases the area of the display area . On the other hand, the electronic device proposed in the present disclosure also includes a specially designed backlight module to guide the light emitted by the light-emitting element to be evenly distributed in the display area located on the side of the camera module opposite to the light-emitting element, so that The overall brightness of the display area is uniform.

The present disclosure has been described with examples and the above-mentioned embodiments, and it should be understood that the present invention is not limited to the disclosed embodiments. On the contrary, the present invention covers a variety of alterations and similar arrangements (for example, those generally known to those skilled in the art). Therefore, additional claims should be based on the broadest interpretation to cover all such Change and approximate layout.

16a‧‧‧First side

16b‧‧‧Second side

161‧‧‧Light-emitting element

50‧‧‧Light guide element

51‧‧‧The first refraction part

51a, 51b, 51c, 52a, 52c, 53a‧‧‧interface

52‧‧‧Second refraction part

53‧‧‧The third refraction part

54‧‧‧Fourth refracting part

a1‧‧‧Angle

a2‧‧‧angle

d‧‧‧Distance

L‧‧‧Light

O1‧‧‧First opening

R‧‧‧Radius

r1‧‧‧Inner diameter

r2‧‧‧Outer diameter

x1, x2‧‧‧horizontal axis

Claims (20)

A backlight module includes: a light guide plate having a first side and a second side opposite to each other; a light emitting element close to the first side of the light guide plate; and a light guide element disposed in the light guide plate , And forming a first opening, the light guide element includes a first refraction portion and a second refraction portion, wherein the first refraction portion has a first refractive index, the second refraction portion has a second refractive index, the The first refractive index and the second refractive index are different from a refractive index of the light guide plate, and the orthographic projection of the first refraction portion on the first side and the orthographic projection of the second refraction portion on the first side The projections do not overlap each other. The backlight module according to claim 1, wherein the first refraction portion and the second refraction portion are located on opposite sides of the first opening. The backlight module according to claim 1, wherein the first refractive index is equal to the second refractive index and smaller than the refractive index of the light guide plate. The backlight module according to claim 3, wherein the light guide element further comprises: a third refraction part connected to the first refraction part and the second refraction part; and a fourth refraction part connected to the first refraction part Portion and the second refraction portion, wherein the third refraction portion and the fourth refraction portion are located on opposite sides of the first opening, and the third refraction portion is closer to the first side than the fourth refraction portion. The backlight module according to claim 4, wherein the third refractive part has a third refractive index, and the fourth refractive part has a fourth refractive index, wherein the third refractive index is equal to the fourth refractive index. The backlight module of claim 5, wherein the third refractive index is equal to the refractive index of the light guide plate. The backlight module according to claim 6, wherein the third refraction portion and the fourth refraction portion are integrally formed with the light guide plate. The backlight module of claim 4, wherein a first interface is formed between the first refraction portion and the third refraction portion, and a second interface is formed between the second refraction portion and the third refraction portion, The first interface and the second interface are separated from each other. The backlight module according to claim 8, wherein the light guide element further comprises: a first reflecting part, which is disposed in the third refraction part and directly connected to the first opening, and is located between the first interface and the second Between interfaces. The backlight module according to claim 9, wherein the first reflective portion has a first reflective surface and a second reflective surface, the first reflective surface is connected to the first interface, and the second reflective surface is connected to the second Interface, and the first anti The emitting surface is connected to the second reflecting surface. The backlight module according to claim 10, wherein an included angle between the first reflective surface and the second reflective surface is between 24 degrees and 166 degrees. The backlight module according to claim 9, wherein the light guide element further comprises: a second reflection part disposed in the fourth refraction part, and the second reflection part and the first reflection part are located in the first opening On opposite sides. The backlight module according to claim 1, wherein the light guide element further comprises: a reflection ring disposed on an inner surface of the first opening. The backlight module according to claim 1, wherein the first refraction portion has a plurality of refraction layers, and the refraction layers are arranged in order in a direction away from the first opening. The backlight module according to claim 14, wherein the refraction layers comprise: a first refraction layer surrounding a part of the second opening; and a second refraction layer surrounding the first refraction layer. The backlight module according to claim 15, wherein the first A refractive index of the refractive layer is smaller than a refractive index of the second refractive layer. The backlight module according to claim 16, wherein the first refraction layer comprises: a third refraction layer surrounding the second refraction layer, wherein the refractive index of the third refraction layer is between that of the first refraction layer And the refractive index of the second refractive layer. The backlight module according to claim 1, wherein the distance between the outer edge of the light guide element and the first opening is d, the radius of the first opening is R, and d≦R/10. The backlight module according to claim 1, wherein the light guide plate has a second opening, and the light guide element is detachably disposed in the second opening. The backlight module according to claim 1, wherein the distance from the light guide element to the second side is smaller than the distance from the light guide element to the first side.

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