TWI662336B - Backlight module with light modulation device - Google Patents

Abstract

The invention provides a backlight module, which includes a bottom plate, a plurality of light sources disposed on the bottom plate, one or more light control devices, and an optical film. The light regulating device is disposed on the bottom plate and covers at least one light source. The light generated by the light source is emitted to the light regulating device, and the light regulating device controls the light. The optical film is disposed on one side of the light control device opposite to the light source; a plurality of light reduction points are provided on the optical film, and the light reduction points respectively project from the optical film to the top surface of the light control device. The dimming point has a projection range on the top surface, and the centroid of the projection range is outside the range of the light emitting hole.

Description

Backlight module with light regulating device

The present invention relates to a backlight module; specifically, the present invention relates to a backlight module having a light regulating device and an optical film provided thereon.

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. Taking a traditional direct-type backlight module as an example, in order to achieve a better light mixing effect in a limited thickness range, a light-regulating film is added above the light source to reflect part of the light emitted by the light source to different positions before passing The light comes out of the light hole. In addition, in order to further enhance the quality of the backlight generated by the backlight module, a diffusion sheet is also added above the light control film to further achieve the effect of uniformly distributing light.

However, as the requirements for reducing the thickness of the backlight module become stricter, the distance between the light-regulating film and the light source is gradually reduced. At this time, the light emitted by the light source may directly penetrate the light-regulating film and emit light in a position where no light hole is provided under unexpected conditions. This condition will affect the uniformity of light, and then produce some bright spots, which will affect the quality of image display.

The purpose of the present invention is to provide a backlight module, which can increase the uniformity of light distribution.

An object of the present invention is to provide a backlight module capable of maintaining a light emitting effect of a light emitting hole on a light regulating device.

The backlight module includes a bottom plate, a plurality of light sources disposed on the bottom plate, one or more light control devices, and an optical film. The light regulating device is disposed on the bottom plate and covers at least one light source. The light generated by the light source is emitted to the light regulating device, and the light regulating device controls the light. A plurality of light emitting holes are formed on the top surface of the light regulating device for allowing light to penetrate and leave the light regulating device. The optical film is disposed on one side of the light control device opposite to the light source; a plurality of light reduction points are provided on the optical film, and the light reduction points respectively project from the optical film to the top surface of the light control device. The dimming point has a projection range on the top surface, and the centroid of the projection range is outside the range of the light emitting hole.

Through the configuration and combination of the above-mentioned backlight module, the light reduction point can further adjust and distribute the light emitted from the light regulating device, and can also reduce the risk that the light reduction point is completely embedded in the light exit hole and affects optical performance.

100‧‧‧ floor

300‧‧‧ light source

500‧‧‧Reflector

700‧‧‧light control device

701‧‧‧light emitting hole

710‧‧‧Top plate

711‧‧‧Top

713‧‧‧block

730‧‧‧Side plate

731‧‧‧ positioning end

900‧‧‧ Optical diaphragm

901‧‧‧ noodles

910‧‧‧light reduction point

930‧‧‧ projection range

931‧‧‧shaped heart

1 is an exploded view of an embodiment of a backlight module; FIG. 2 is a sectional view of an embodiment of a backlight module; FIG. 3 is a plan view of an embodiment of a backlight module; and FIG. 4 is a plan view of another embodiment of a backlight module; FIG. 5 is a plan view of another embodiment of the backlight module; FIG. 6 is a schematic view of an embodiment of a light reduction point and a light emitting hole; FIG. 7 is a plan view of an embodiment of a light control device.

The invention provides a backlight module, which is preferably applicable to a 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.

As shown in FIG. 1, the backlight module includes a base plate 100, a plurality of light sources 300, one or more light control devices 700, and an optical film 900. The base plate 100 is preferably made of plastic or metal for carrying the light source 300 and a circuit for controlling the light source 300. The light source 300 is preferably a point light source, such as a light emitting diode, but is not limited thereto. The light sources 300 are preferably arranged in a matrix of rows and columns on the base plate 100 to form rows and columns in different directions. However, in different embodiments, the light sources 300 may be arranged in other ways. Preferably, the backlight module further includes a reflective sheet 500 covering the bottom plate 100 and allowing the light source 300 to pass through the reflective sheet 500 to emit light outward. Part of the light emitted by the light source 300 can be directly or indirectly reflected and recovered by the reflective sheet 500 to improve the efficiency of using the light.

As shown in FIG. 1, the light control device 700 is disposed on the reflective sheet 500 and the bottom plate 100 and covers at least one light source 300. Preferably, the light generated by the light source 300 is emitted to reach the light regulating device 700, and the light regulating device 700 regulates the light. For example, the light control device 700 may reflect part of the light to different positions and then allow the light to leave the light control device 700 and reach the optical film 900 above, thereby making the light distribution more uniform, but not limited thereto; the light control device 700 Other types of adjustments to light, such as travel direction, phase, color, etc. can also be made.

In this embodiment, the light control device 700 is formed in a long shape and has a top plate 710 and two opposite side plates 730. The top plate 710 is formed in a long rectangular shape and extends along the rows or columns of the light source 300 arrayed, and the two side plates 730 are respectively bent and protruded from the relatively long ends of the top plate 710. The top plate 710 has a top surface 711. A plurality of light emitting holes 701 are preferably formed on the top surface 711 to allow light to pass through. The two side plates 730 may be parallel to each other, but may also be opened outward or contracted inward relative to the top plate 710. Each side plate 730 has a positioning end 731 away from the top plate 710, and the light regulating device 700 is disposed on the reflection sheet 500 through the positioning end 731 and covers the light source 300 in one row, half row, one column, or half column.

As shown in FIGS. 1 and 2, the optical film 900 is disposed on a side of the light control device 700 opposite to the light source 300. In this embodiment, the optical film 900 is preferably disposed on the top surface 711 and is supported by the light regulating device 700; however, in different embodiments, the optical film 900 may also be provided on other structures by supporting it. Above the light control device 700. The optical film 900 preferably includes a diffusion sheet, a diaphragm, a brightness enhancement sheet, a polarizer, and the like, but is not limited thereto.

As shown in FIG. 1 and FIG. 2, a plurality of light reduction points 910 are provided on the optical film 900; the light reduction points 910 protrude from the optical film 900 to the top surface 711, respectively. The light reduction point 910 has the effect of reflecting or absorbing light; after the light leaves the light control device 700 from the light exit hole 701, if it reaches the position where the light reduction point 910 is arranged, it will be reflected or absorbed, and cannot The position passes through the optical diaphragm 900. In other words, by setting the dimming point 910, the brightness of the local position can be adjusted. In a preferred embodiment, the light reduction point 910 can be provided on the side of the optical film 900 facing the top surface 711 by printing ink, but it is not limited thereto.

As shown in FIGS. 2 and 3, the light reduction point 910 has a projection range on the top surface 711. 930, and the centroid 931 of the projection range 930 is outside the range of the light emitting hole 701. With this arrangement, even if the light reduction point 910 interferes with the top surface 711, it will not be completely blocked by the light exit hole 701 and cause blocking, ensuring that at least part of the light can still exit through the light exit hole 701 and leave the light control device. 700. Specifically, when the optical film 900 is supported by the top plate 710, this setting will increase the chance of the contact point between the light reduction point 910 and the top surface 711 outside the light exit hole 701, so that the top surface 711 can pass the light reduction. Point 910 supports the optical film 900.

As shown in FIG. 2, in this embodiment, since the optical film 900 is supported by the top surface 711 via the light reduction point 910, the distance between the optical film 900 and the top surface 711 is not greater than that of the light reduction point 910. height. Preferably, the distance between the optical film 900 and the top surface 711 is the height of the light reduction point 910; however, in different embodiments, since the light reduction point 910 may still partially fall into the light exit hole 701, the optical The distance between the diaphragm 900 and the top surface 711 will be smaller than the height of the light reduction point 910. In addition, in the embodiment shown in FIG. 2, the light reduction point 910 has a circular arc-like outer surface, and the top of the outer surface is in contact with the top surface 711 to be supported by the top surface 711; however, in different embodiments, The light reduction spot 910 may be formed into another shape.

FIG. 3 is a schematic diagram showing a part of the top surface 711. In the embodiment shown in FIG. 3, the range of the light exit hole 701 extends at least beyond the projection range 930 of the nearest light reduction point, thereby further reducing the chance that the light reduction point 910 blocks the light exit hole 701. However, in different embodiments, as shown in a part of the top surface 711 area shown in FIG. 4, the light exit hole 701 may also fall completely within the projection range 930 of the light reduction point to provide greater optical design flexibility. As long as the centroid 931 of the projection range 930 is outside the range of the light emitting hole 701, it is sufficient to reduce the risk that the light reduction point 910 blocks the light emitting hole 701. In the embodiment shown in FIG. 5, the range of the light emitting hole 701 on the top surface 711 and the closest projection range 930 do not overlap at all. In this embodiment, the contact position of the light reduction point 910 and the top surface 711 must be a range other than the light exit hole 701. Therefore, it is impossible for the light reduction point 910 to block the light emitting hole 701.

In the embodiment shown in FIG. 6, the top end of the light reduction point 910 is supported by a portion of the top surface 711 which is not provided with the light emitting hole 701. In this preferred embodiment, the maximum width D of the light reduction point 910 preferably conforms to the following relationship: D > 1.7 H + d (Equation 1)

Among them, D: the maximum width of the light reduction point 910; H: the distance between the top surface 711 and the top surface 711 of the optical film 900; d: the diameter of the light exit hole 701 closest to the light reduction point 910.

With this arrangement, the light reduction spot 910 can have a sufficient area to provide a desired light control effect. In addition, when the light reduction point 910 has a circular bottom connected to the surface 901, the maximum width D is preferably the diameter of the circular bottom. However, in different embodiments, when the bottom of the light reduction point 910 is rectangular or other shapes, the maximum width D may be one side length, diagonal length, or other maximum width in a certain direction. In addition, the light reduction point 910 has a maximum thickness T, and the distance H is preferably not greater than the maximum thickness T, so that the overall thickness of the backlight module is further reduced.

In a preferred embodiment, the arrangement density and number of the light reduction points 910 can be determined according to the light output effect of the light control device 700. As shown in FIG. 7, the top surface 711 is divided into a plurality of blocks 713, and the light intensity in each block 713 is measured or simulated separately, and is the smallest value obtained from the standard value (for example, the smallest value obtained by counting the brightness values of all blocks 713). Or the first quartile) to determine the compensation value that requires dimming. Since the light emitting holes 701 in each block 713 have different sizes, the size of the corresponding dimming point 910 suitable for each block 713 is also different. Each of these can be customized by using the formula of the above formula 1, for example. The size of the dimming point 910 corresponding to the block 713. When the dimming compensation value for each block 713 is obtained, The reflectance of the material of the light reduction point 910 and the size of the light reduction point 910 can be used to estimate the distribution number of the light reduction points 910 corresponding to each block 713 to obtain the desired optical effect.

For example, when the distance H between the surface 901 and the top surface 711 is 0.05 mm and the diameter d of the light emitting holes 701 distributed in a specific block 713 is 0.2 mm, then the equation (1) above can be calculated to correspond to this The maximum width D of the light reduction points 910 arranged in a block 713 should be greater than 0.285 mm, so the area of each light reduction point 910 (assuming a round point) corresponding to this block 713 should be greater than 0.064 mm ² . If the area A _pixel of this block 713 is 25 mm ² , and the original measured brightness compensation value C is 20% relative to the standard brightness, and the reflectance R of the material 910 is 80%, then The total area A _{ink of the} dimming point 910 that should be arranged corresponding to this block 713 is obtained by the formula: From the minimum area of the dimming point 910 0.064mm ² obtained above and the total area of the dimming point 910 A _ink , the minimum number of dimming points N corresponding to this block 713 can be calculated by the following formula: Preferably, the dimming point 910 is arranged to correspond to the block 713 whose brightness is greater than the standard brightness, and the block 713 whose brightness is less than the standard brightness is preferably not to correspond to the dimming point 910.

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 (8)

A backlight module includes: a base plate; a plurality of light sources are respectively disposed on the base plate; at least one light control device is disposed to cover the light sources; wherein the control device has a top surface, the top surface A plurality of light emitting holes are arranged; and an optical film is disposed on a side of the light regulating device opposite to the light sources; a plurality of light reduction points are provided on the optical film and project from the optical film to the top surface, respectively. Wherein, the light reduction points respectively have a projection range on the top surface, and the centroid of the projection range is outside the range of the light emitting holes. The backlight module according to claim 1, wherein a range of the light emitting holes at least partially protrudes beyond the closest projection range. The backlight module according to claim 2, wherein the range of the light emitting holes does not overlap with the closest projection range. The backlight module according to claim 1, wherein the light reduction points have a maximum width D conforming to the following relationship: D > 1.7 H + d, where D: the maximum width of the light reduction points; H: the optical film The distance between one surface facing the top surface and the top surface; d: the diameter of the light emitting hole closest to the light reduction points. The backlight module according to claim 1, wherein the light regulating device has: a top plate; and two side plates, which are respectively bent and protruded from two opposite ends of the top plate; each of the side plates has a positioning end away from the top plate; ; Wherein the top surface is formed on the top plate. The backlight module according to claim 1, wherein a distance between the optical film and the top surface is not greater than a height of the light reduction points. The backlight module according to claim 6, wherein the optical film is supported by the top surface. The backlight module according to claim 6, wherein at least part of the top ends of the dimming points are in conflict with the top surface.