TWI641895B - Backlight module and display device - Google Patents

Abstract

The invention provides a backlight module, which includes a light source device, a reflective curved surface, and a cavity. The light source device includes one or more light sources distributed along the first direction. The reflective curved surface extends along the first direction, and reflects the light generated by the light source into the cavity. The reflection surface has a first-order surface and a second-order surface. The first-order curved surface and the second-order curved surface are arranged side by side, respectively extending in the first direction, and forming an indentation with respect to the light source on a cross section perpendicular to the first direction. The second-order curved surface is closer to the light source device than the first-order curved surface and forms a stepped structure with the first-order curved surface.

Description

Backlight module and display device including the same

The present invention relates to a backlight module having a reflective curved surface and a display device using the same. Specifically, the present invention relates to a backlight module having a reflective curved surface with a stepped structure design and a display device using the same.

Flat and curved display devices have been widely used in various electronic devices, such as mobile phones, personal wearable devices, televisions, host computers for transportation, personal computers, digital cameras, handheld video games, and the like. However, with the continuous improvement of specifications such as resolution and narrow bezels, the optical design in display devices has also been tested.

Taking a liquid crystal display device as an example, its optical performance is usually related to a backlight module disposed behind the display panel. Traditionally, backlight modules can be roughly divided into two types: edge-lit and direct-lit. Among them, one type of edge-lit backlight module is first performed by a concave reflective element disposed on the side of the display area when the light source emits light Reflect to direct light under the display area; and then reflect through the reflective sheet below the display area to generate a backlight. However, this type of backlight module may generate a bright band on the display area near one side of the light source, thereby causing problems in use.

An object of the present invention is to provide a backlight module and a display device including the same. Can reduce the situation of local bright band on the light source side.

Another object of the present invention is to provide a backlight module and a display device including the same, which can reduce the occurrence of color shift on the light source side.

The display device includes a display panel and a backlight module. The display panel is stacked on the backlight module to receive light from the backlight module. The backlight module includes a light source device, a reflective curved surface, and a cavity. The light source device includes one or more light sources distributed along the first direction. The reflection curved surface extends along the first direction and is sandwiched with the light source device to form a light outlet; and the cavity has a light entrance end facing the light outlet to receive the light reflected by the reflection curved surface.

The reflection surface has a first-order surface and a second-order surface arranged side by side. The first-order curved surface extends along the first direction, and forms a recess with respect to the light source on a cross section perpendicular to the first direction. The second-order curved surface also extends along the first direction, and forms a recess with respect to the light source on a cross section perpendicular to the first direction. The second-order curved surface is closer to the light source device than the first-order curved surface and forms a stepped structure with the first-order curved surface. The second-order curved surface has a second-order lateral edge close to the first-order curved surface, and a step height is sandwiched between the second-order lateral edge and the first-order curved surface.

With the aforementioned stepped structure design, the proportion of the light emitted from the light exit port toward the end of the light source device can be reduced, so the proportion of light that directly reaches the light exit surface of the cavity without being reflected by the reflecting portion can be reduced, thereby reducing the light exit surface of the cavity. Concentration of light near the light entrance side.

G‧‧‧step height

10‧‧‧ backlight module

30‧‧‧Display Panel

100‧‧‧light source device

110‧‧‧light source substrate

130‧‧‧light source

131‧‧‧ light-emitting surface

133‧‧‧ normal of luminous surface

151‧‧‧First exposure range

152‧‧‧Second exposure range

200‧‧‧light exit

300‧‧‧ reflective surface

301‧‧‧base

310‧‧‧First-order surface

320‧‧‧ second-order surface

321‧‧‧Second-order side edge

323‧‧‧Second step boss

325‧‧‧second-stage boss

330‧‧‧step difference

500‧‧‧ Cavity

501‧‧‧Incoming light end

510‧‧‧Reflection

530‧‧‧Optical diaphragm

610‧‧‧The first parabola

620‧‧‧second parabola

1 is an exploded view of an embodiment of a display device; FIG. 2 is a sectional view of an embodiment of a display device; FIG. 3 is a partially enlarged schematic view of an embodiment of a reflective curved surface; 4 is a schematic cross-sectional view of the embodiment shown in FIG. 3; FIG. 5 is a schematic view of another embodiment of a reflective curved surface; FIG. 6 is a schematic cross-sectional view of the embodiment shown in FIG. 5; FIG. 8 is a schematic diagram of another embodiment of a reflective curved surface; FIG. 9 is a schematic diagram of an embodiment in which the reflective curved surface shown in FIG. 8 is matched with a light source device; and FIG.

The invention provides a display device and a backlight module included in the display device. The display device preferably includes a non-self-luminous display panel such as a liquid crystal display panel or an electrophoretic display panel; and it can be preferably applied to a computer monitor, a television, a monitor, or a vehicle mainframe. In addition, the display device can also be applied to other electronic devices, for example, as a display screen of a mobile phone, a digital camera, a handheld game instrument, and the like.

In the embodiment shown in FIG. 1, the display device includes a display panel 30 and a backlight module 10. The display panel 30 is stacked on the backlight module 10 to receive light from the backlight module 10. The backlight module 10 includes a light source device 100, a reflective curved surface 300, and a cavity 500. As shown in FIG. 1, the light source device 100 includes a light source substrate 110 and a plurality of light sources 130. In this embodiment, the light source substrate 110 is a metal or other material heat-dissipation substrate that is elongated along the first direction X; the light sources 130 are distributed on the light source substrate 110 along the first direction X. In addition, the light source 130 may be firstly arranged on a long flexible circuit board or a printed circuit board, and then disposed on the light source substrate 110 through the above-mentioned circuit board. In this embodiment, the light source 130 is preferably a light emitting diode; however, in different embodiments, the light source 130 may be a single or a plurality of light sources extending along the first direction X, such as a cathode ray lamp. Tube etc.

The reflective curved surface 300 extends along the first direction X, and is preferably set to correspond to the light source 130. Specifically, as shown in the sectional view of FIG. 2, the reflective curved surface 300 is preferably provided with a light emitting surface 131 facing the light source 130, that is, the light source. 130 Surface that emits light. The reflective curved surface 300 is located below a side of the light source substrate 110 where the light source 130 is disposed, and is connected to the light source substrate 110 at one end parallel to the first direction X, but is not limited thereto. In addition, the other end of the reflective curved surface 300 parallel to the first direction X and opposite to the light source substrate 110 is preferably sandwiched with the light source device 100 to form a light outlet 200. The light emitted by the light source 130 can be reflected from the reflective curved surface 300 and emitted from the light exit port 200. In this embodiment, the reflective curved surface 300 is supported by the base 301. The base 301 may be made of metal, plastic, or other materials; the reflective curved surface 300 may be formed by surface-treating the surface of the base 301, or may be formed by attaching other materials to the base 301.

As shown in FIGS. 1 and 2, the reflective curved surface 300 includes a first-order curved surface 310 and a second-order curved surface 320. The first-order curved surface 310 and the second-order curved surface 320 respectively extend along the first direction X; preferably, both of them are linearly distributed in the first direction X without bending, but are not limited thereto. The second-order curved surface 320 is closer to the light source device 310 than the first-order curved surface 310. In other words, in the orientation shown in FIG. 2, the second-order curved surface 320 is located closer to the top of the slope on the slope surface formed by the reflective curved surface 300 as a whole. Is closer to the light source substrate 110; and the first-order curved surface 320 is located closer to the foot of the slope. In a preferred embodiment, the base 301 is connected to the light source substrate 110, and one end of the second-order curved surface 320 is close to or even connected to the light source substrate 110.

The first-order curved surface 310 and the second-order curved surface 320 are both concave with respect to the light source 130 on a section perpendicular to the first direction X (for example, the section shown in FIG. 2), and the first-order curved surface 310 and the second-order curved surface are added. The curved surfaces 320 all extend along the first direction X. So first-order surface 310 and second-order surface 320 are respectively formed as open arc grooves extending along the first direction X. In addition, the first-order curved surface 310 and the second-order curved surface 320 together form a stepped structure. The second-order curved surface 320 is preferably convex toward the light exit 200 or retracted in the opposite direction relative to the first-order curved surface 310. As shown in FIG. 1 and FIG. 2, the second-order curved surface 320 has a second-order lateral edge 321 near one of the first-order curved surfaces 310. The second-order lateral edge 321 is preferably parallel to the first direction X. The second-order side edge 321 and the first-order curved surface 310 have a step height G, which forms the aforementioned stepped structure. The step height G is larger than 0, and preferably not larger than 0.8 mm. With this arrangement, the proportion of the light reflected from the reflective curved surface 300 to be above the light exit port 200 (ie, closer to the light source substrate 110 side) can be reduced.

The cavity 500 is preferably composed of a reflection portion 510 and an optical film 530. The reflective portion 510 is preferably connected to one end of the reflective curved surface 300 opposite to the light source device 100, and the optical film 530 is disposed opposite to the reflective curved surface 300 and is preferably connected to the light source substrate 110. The optical film 530 may preferably be a diffusion sheet, a brightness enhancement sheet, or other light-transmitting plates. In addition, the optical film 530 may also be a substrate, a polarizer, or other light-transmitting plate provided on the bottom surface of the display panel. The reflecting portion 510 and the optical film 530 are clamped together to form a light entrance end 501 toward one end of the light exit port 200. The light entrance end 501 faces the light exit port 200 to receive light emitted from the light exit port 200. After the light enters the cavity 500, it is preferably reflected by the reflection portion 510 and reaches the optical film 530. With the aforementioned stepped structure design, the proportion of the light emitted from the light exit port 200 toward the optical film 530 can be reduced, so the proportion of light that directly reaches the optical film 530 without being reflected by the reflection portion 510 can be reduced, thereby reducing Concentration of light on the side of the diaphragm 530 near the light-entry end 501.

In the embodiment shown in FIG. 3, the second-order curved surface 320 is lifted toward the light source 130 or the light exit 200 relative to the first-order curved surface 310. In this embodiment, the pedestal 301 having a stepped structure is formed by an integral forming method such as an aluminum extrusion process, and then the first First-order curved surface 310 and second-order curved surface 320. However, in the embodiment shown in FIG. 1 and FIG. 2, an additional diaphragm, metal tape, or other materials may be attached to the first-order curved surface 310 on the base 301 to form a lift and have Segmented second-order surface 320.

In addition, as shown in FIG. 3, the reflective curved surface 300 further includes a step surface 330. The two ends of the step surface 330, preferably opposite ends parallel to the first direction X, are connected to the second-order side edge 321 and the first-order curved surface 310, respectively. The step surface 330 and the second-order curved surface 320 form a convex ridge at the second-order side edge 321.

In a section perpendicular to the first direction X, such as the section shown in FIG. 4, the section line of the first-order curved surface 310 is substantially a part of the first parabola 610, and the section line of the second-order curved surface 320 is substantially Part of the second parabola 620. The first parabola 610 and the second parabola 620 preferably have the same shape, but the first parabola 610 is translated toward the cavity 500 than the second parabola 620 in a direction in which the parallel optical film 530 extends. The first parabola 610 has a first focus F ₁ and the second parabola 620 has a second focus F _{2. The positions} of the first focus F ₁ and the second focus F ₂ are different. In this preferred embodiment, the first focus F ₁ and the second focus F ₂ both fall outside one side of the light source substrate 110 carrying the light source 130. The first focus F ₁ is farther from the cavity 500 than the second focus F ₂ . The light source 130 is preferably at least partially located on the first focus F ₁ , for example, the first focus F ₁ falls on the center of the light emitting surface 131. However, in different embodiments, the light emitting surface 131 may also partially fall on the line connecting the first focus F ₁ and the second focus F ₂ . With this setting, the light generated by the light source 130 can be sent to the deeper part of the cavity 500 through the reflection of the first-order curved surface 310 to maintain the uniformity of the light distribution, and at the same time, it can be lifted by the second-order curved surface 320 A defocusing effect is generated to reduce the concentration of light at the proximal end of the optical film 530.

In the embodiment shown in FIG. 5, the second-order curved surface 320 is retracted away from the light source 130 or the light exit 200 relative to the first-order curved surface 310. In this embodiment, for example, an aluminum extrusion process is used. The monolithic forming method is used to form the base 301 with a stepped structure, and the first-order curved surface 310 and the second-order curved surface 320 are formed by surface treatment, respectively. However, in different embodiments, additional membranes, metal tapes, or other materials may be attached to the second-order curved surface 320 on the base 301 to form a first-order curved surface 310 that is raised and has a step.

In a section perpendicular to the first direction X, such as the section shown in FIG. 6, the section line of the first-order curved surface 310 is substantially a part of the first parabola 610, and the section line of the second-order curved surface 320 is substantially Part of the second parabola 620. The first parabola 610 and the second parabola 620 preferably have the same shape, but in a direction in which the parallel optical film 530 extends, the second parabola 620 is translated toward the cavity 500 than the first parabola 610. The first parabola 610 has a first focus F ₁ and the second parabola 620 has a second focus F _{2. The positions} of the first focus F ₁ and the second focus F ₂ are different. In this preferred embodiment, the first focus F ₁ and the second focus F ₂ both fall outside one side of the light source substrate 110 carrying the light source 130, and the second focus F ₂ is farther from the cavity 500 than the first focus F ₁ . The light source 130 is preferably at least partially located on the first focus F ₁ , for example, the first focus F ₁ falls on the center of the light emitting surface 131. However, in different embodiments, the light emitting surface 131 may also partially fall on the line connecting the first focus F ₁ and the second focus F ₂ . With this arrangement, the light generated by the light source 130 can be sent to the deeper part of the cavity 500 through the reflection of the first-order curved surface 310 to maintain the uniformity of the light distribution, and at the same time can be retracted by the second-order curved surface 320 A defocusing effect is generated to reduce the concentration of light at the proximal end of the optical film 530.

As shown in FIG. 7, the light source 130 has a full-height full-width opening angle θ. Preferably, the full-height full-width opening angle θ refers to a range of opening angles in the emission spectrum of the light source 130 that is greater than or equal to half of its intensity peak. In a cross section perpendicular to the first direction X, as shown in the cross section in FIG. 7, the two ends of the cross-section of the light emitting surface 131 are respectively opened at the full-width half-width opening angle θ with respect to the light surface normal 133 to open the first irradiation range 151 and the second Illumination range 152. The first irradiation range 151 and the second irradiation range 152 are preferably Partially overlapped, and all are distributed in a conical shape, so they are all formed into a fan-shaped range on the cross section shown in FIG. 7. As shown in FIG. 7, on this cross section, the section line of the second-order curved surface 320 completely falls within the combined set range of the first irradiation range 151 and the second irradiation range 152. However, in different embodiments, the intercept line of the second-order curved surface 320 may only partially fall within the range of one of the first irradiation range 151 or the second irradiation range 152. With this arrangement, it is possible to reduce the situation in which the light of higher intensity generated by the light source 130 directly hits the front end of the optical film 530.

In the foregoing embodiment, the second-order curved surface 320 is a whole strip-shaped and is arranged on the entire length of the reflective curved surface 300 in the first direction X without interruption. However, in the embodiment shown in FIG. 8, the second-order curved surface may be arranged in sections on the entire length of the reflective curved surface 300 along the first direction X, and includes a plurality of second-order boss surfaces 323. Specifically, a plurality of second-stage bosses 325 are provided on one surface of the base 301 facing the light source 130. The second-stage bosses 325 are distributed along the first direction X space, and the surface is formed as a second-stage boss surface. 323.

As shown in FIG. 9, the second-stage boss surfaces 323 are preferably formed in a rectangular shape, and the centroid distance P between the centers of the two second-stage boss surfaces 323 adjacent to each other. As mentioned above, the plurality of light sources 130 are arranged along the first direction X, preferably corresponding to the second-stage boss surfaces 323 in a many-to-one or one-to-one manner, but not limited thereto. In addition, the centroid distance between two adjacent light sources 130 is D, and the ratio P / D is preferably not greater than 15 or P is not greater than 200 mm. Since the color tone of the light at each position on the light emitting surface 131 of the light source 130 may be different, by this design, the difference in light intensity of each color of each position in the first direction X along the first edge of the optical film 500 can be maintained within a certain range, for example, less than 50% to reduce the occurrence of bright bands and color casts at the front end.

In the embodiment shown in FIG. 10, the second-step boss surface 323 has a length L in the first direction X. The ratio L / P between the length L and the centroid distance P of the adjacent second and second stage boss surfaces 323 is preferably not less than 0.4 and less than 1; that is, 0.4 L / P <1. Because the color tone of the light at each position on the light emitting surface 131 of the light source 130 may be different, by this setting, the difference in light intensity of each color at each position of the leading edge of the optical film 500 can be maintained within a certain range, for example, less than 100%, in order to reduce The front end is too bright and color shifted.

The present invention has been described by the above related embodiments, but the above embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the invention. On the contrary, modifications and equal settings included in the spirit and scope of the scope of patent application are all included in the scope of the present invention.

Claims (12)

A backlight module includes: a light source device including at least one light source distributed along a first direction; a reflective curved surface extending along the first direction and sandwiched with the light source device to form a light outlet; wherein the reflective curved surface It has a first-order curved surface extending along the first direction and forming an indentation with respect to the at least one light source on a cross section perpendicular to the first direction; and a second-order curved surface extending along the first direction and in A cross section perpendicular to the first direction forms an indentation with respect to the at least one light source, and the second-order curved surface includes a plurality of second-order boss surfaces distributed along the first direction; wherein the second-order curved surface is greater than the first-order curved surface. The curved surface is close to the light source device, and forms a stepped structure with the first-order curved surface; the second-order curved surface has a second-order side edge close to the first-order curved surface, and the second-order side edge and the first-order curved surface A difference in height is sandwiched between the curved surfaces; and a cavity having a light entrance end facing the light exit. The backlight module according to claim 1, wherein the step height is greater than 0 and not greater than 0.8 mm. The backlight module according to claim 1, wherein the second-order curved surface is lifted toward the light sources relative to the first-order curved surface. The backlight module according to claim 1, wherein the second-order curved surface is retracted relative to the first-order curved surface away from the light sources. The backlight module according to claim 1, wherein a section line of the first-order curved surface on a section perpendicular to the first direction is substantially a part of a first parabola, and a section of the second-order curved surface on the section The line is essentially a part of a second parabola, and the focus of the first parabola is different from the focus of the second parabola. The backlight module according to claim 5, wherein at least part of the light source falls on a focal point of the first parabola. The backlight module according to claim 1, wherein the light source has a light-emitting surface and a half-height full-width opening angle; on a cross section perpendicular to the first direction, two ends of a cross-section of the light-emitting surface are opposite to the light-emitting surface normal to The half-height full-width opening angle opens a first irradiation range and a second irradiation range, and a section line of the second-order curved surface at least partially falls within the first irradiation range and / or the second irradiation range. The backlight module according to claim 7, wherein the cut line of the second-order curved surface completely falls within the first irradiation range and / or the second irradiation range. The backlight module according to claim 1, wherein the reflective curved surface includes a step surface, and two ends of the step surface are respectively connected to the second-order side edge and the first-order surface, and the step surface and the second-order surface A convex ridge is formed at the second-order side edge. The backlight module according to claim 1, wherein the centroid distance between two adjacent second-stage boss surfaces is not more than 200 mm. The backlight module according to claim 1, wherein the at least one light source includes a plurality of light sources, and a ratio of a centroid distance between two adjacent second-stage boss surfaces and a centroid distance between two adjacent light sources is not greater than 15. The backlight module according to claim 1, wherein a ratio of a length of each second-stage boss surface in the first direction to a centroid distance between two adjacent second-stage boss surfaces is not less than 0.4 and less than 1 .