Display device

A display device includes a first light source, a second light source, a liquid crystal panel, and a light-guide device. The liquid crystal panel is disposed on the first light source and the second light source. The light-guide device is disposed between the first light source and the liquid crystal panel. A first light-receiving surface of the light-guide device faces toward the first light source. A second light-receiving surface of the light-guide device faces toward the second light source. A first light beam emitted by the first light source enters the light-guide device through the first light-receiving surface and leaves the light-guide device through a light-emitting surface opposite to the first light-receiving surface. A second light beam emitted by the second light source enters the light-guide device through the second light-receiving surface and leaves the light-guide device through the light-emitting surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 107101388, filed on Jan. 15, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a display device, and particularly relates to a display device having a first light source and a second light source.

2. Description of Related Art

Through the development of science and technology, various vehicles are equipped with a display device. Such display device not only displays traffic information (e.g., satellite navigation) to the driver, but may also be configured to display entertaining contents (e.g., gaming or movies) to the passenger next to the driver.

However, when the driver drives the vehicle, if the display device displays entertaining contents, the driver may be distracted by the contents, and an accident is more likely to occur. Therefore, a method for controlling a viewing angle of a display device is needed. With the method, when the display device displays entertaining contents, the driver is unable to view the frame of the display device, so the driver is not distracted and the chance of occurrence of an accident is reduced.

SUMMARY OF THE INVENTION

One or some exemplary embodiments of the invention provide a display device capable of controlling a viewing angle.

At least one display device according to an embodiment of the invention includes a first light source, a second light source, a liquid crystal panel, and a light-guide device. The liquid crystal panel is disposed on the first light source and the second light source. The light-guide device is disposed between the first light source and the liquid crystal panel. A first light-receiving surface of the light-guide device faces toward the first light source. A second light-receiving surface of the light-guide device faces toward the second light source. A first light beam emitted by the first light source enters the light-guide device through the first light-receiving surface and leaves the light-guide device through a light-emitting surface opposite to the first light-receiving surface. A second light beam emitted by the second light source enters the light-guide device through the second light-receiving surface and leaves the light-guide device through the light-emitting surface.

According to one or some exemplary embodiments of the invention, the viewing angle of the display device is controlled by using the first light source and the second light source.

DESCRIPTION OF THE EMBODIMENTS

The invention now will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As appreciated by those of ordinary skill in the art, various different modifications may be made to the embodiments described hereinafter without departing from the spirit or scope of the invention.

The terms used herein such as “about”, “approximate”, or “substantial” include a related value and an average within an acceptable deviation range of specific values determined by those with ordinary skills in the art with consideration of discussed measurement and a specific number of errors related to the measurement (i.e., a limitation of a measurement system). For example, the term “about”, “approximate”, or “substantial” may represent those within one or a plurality of standard deviations of the related value, such as within ±30%, ±20%, ±10%, ±5%.

Unless otherwise defined, all of the terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skills in the art to which the invention belongs. It will be further understood that the terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Exemplary embodiments of the disclosure are described with reference of schematic cross-sectional and top views of the idealized embodiments. Therefore, a shape variation serving as a result of a manufacturing technique and/or manufacturing tolerance is omitted from the drawings. Therefore, the embodiments of the invention should not be interpreted as being limited to specific shapes shown in the drawings but may include a shape deviation caused during manufacture, for example. For example, a flat area shown in the figures or described herein may practically have rough and/or non-linear characteristics. Moreover, an acute angle shown in the drawings can practically be a rounded angle. Therefore, the shapes shown in the figures are substantially schematic, and the shapes therein are not intended to represent accurate shapes, and are not intended to serve as limitations of the claims.

FIG. 1is a schematic cross-sectional view illustrating a display device according to an embodiment of the invention.

Referring toFIG. 1, a display device10includes a first light source E1, a second light source E2, a liquid crystal panel P, and a light-guide device100.

The first light source E1and the second light source E2may be a light emitting diode, a bulb, a light tube, or other light emitting devices, for example. In the embodiment, the first light source E1is disposed on a circuit board B1, and the second light source E2is disposed on a circuit board B2. In the embodiment, the circuit board B1is disposed at a bottom of a case BZ, for example, and the circuit board B2is disposed on a sidewall of the case BZ, for example. Even though the circuit board B2and the circuit board B1of the embodiment are two separate circuit boards, the invention is not limited thereto. In some embodiments, the circuit board B2and the circuit board B1are connected with each other, and the connected circuit boards are bended at a corner of the case BZ, for example.

The liquid crystal panel P is disposed on the first light source E1and the second light source E2, for example. The liquid crystal panel P includes a polarizer, a pixel array substrate, liquid crystal, and a color filter, for example. However, the invention is not limited thereto. In some embodiment, another liquid crystal panel may be further disposed on the liquid crystal panel P, and the another liquid crystal panel may omit a color filter, for example. However, the invention is not limited thereto.

The light-guide device100is located between the first light source E1and the liquid crystal panel P. The light-guide device100includes a light-guide plate, for example. In addition, a material of the light-guide plate includes, for example, polymethyl methacrylate (PMMA), polycarbonate (PC), glass, polydimethylsiloxane (PDMS), polyethylene terephthalate (PET) or other materials capable of guiding light.

A first light-receiving surface X1of the light-guide device100faces toward the first light source E1. A second light-receiving surface X2of the light-guide device100faces toward the second light source E2. In the embodiment, the second light-receiving surface X2is connected with the first light-receiving surface X1and a light-emitting surface T. However, the invention is not limited thereto.

A first light beam L1emitted by the first light source E1enters the light-guide device100through the first light-receiving surface X1, and leaves the light-guide device100through the light-emitting surface T opposite to the first light-receiving surface X1to arrive at the liquid crystal panel P. Even thoughFIG. 1illustrates that each first light source E1emits one first light beam L1, each first light source E1of the embodiments of the invention emits more than just one first light beam L1. In practice, each first light source E1of the embodiments of the invention may emit an infinite number of first light beams L1from different angles.

A second light beam L2emitted by the second light source E2enters the light-guide device100through the second light-receiving surface X2, and leaves the light-guide device100through the light-emitting surface T after being reflected by the first light-receiving surface X1to arrive at the liquid crystal panel P. Even thoughFIG. 1illustrates one second light beam L2, the second light source E2of the embodiments of the invention emits more than just one second light beam L2. In practice, each second light source E2of the embodiments of the invention may emit an infinite number of second light beams L2from different angles.

An included angle between a first average light-emitting direction D1of the first light beam L1leaving the light-emitting surface T and the light-emitting surface T is a first included angle α1. An included angle between a second average light-emitting direction D2of the second light beam L2leaving the light-emitting surface T and the light-emitting surface T is a second included angle α2. In the embodiment, the included angle α1between the first average light-emitting direction D1and the light-emitting surface T is greater than the included angle α2between the second average light-emitting direction D2and the light-emitting surface T.

Since the first average light-emitting direction D1is different from the second average light-emitting direction D2, a switchable viewing angle of the display device10may be adjusted by choosing to turn on the first light source E1or the second light source E2. For example, when the first light source E1is turned on and the second light source E2is turned off, the viewing angle of the display device10is a front viewing angle (about 0 degrees). If the second light source E2is turned on and the first light source E1is turned off, the viewing angle of the display device10may be deviated from the front and toward the side view angle. In other words, by turning on/off of the first light source E1and the second light source E2, the viewing angle of the display device10for a user is controlled.

In some embodiments, the first light source E1and the second light source E2may be turned on at the same time to increase the brightness of a frame displayed by the display device10.

In the embodiment, the display device10may optionally further include a first optical film F1. The first optical film F1is disposed between the light-guide device100and the first light source E1. An optical distance OD is kept in advance between the first light source E1and the first optical film F1. The optical distance OD offers a sufficient space for light emitted by the adjacent first light sources E1to be mixed with each other.

The first optical film F1may be a diffuser film, for example. However, the invention does not intend to limit that the first optical film F1includes only one film. In some embodiments, the first optical film F1further includes a diffuser plate, a quantum dot enhancement film (QDEF), a phosphor film, a prism film, a dual brightness enhancement film (DBEF), a grating film, other optical films or a combination thereof.

In the embodiment, the display device10may optionally further include a second optical film F2. The second optical film F2is disposed between the light-guide device100and the liquid crystal panel P.

The second optical film F2may be, for example, a diffuser film, a quantum dot enhancement film (QDEF), a phosphor film, a light-guide film, a prism film, a dual brightness enhancement film (DBEF), a grating film, other optical films, or a combination thereof. In some embodiments, the second optical film F2is meshed.

In some embodiments, the second optical film F2is disposed to refract the first light beam L1and/or the second light beam L2. In some embodiment, when a light-emitting angle of the second light beam L2is excessively large, the second optical film F2may direct a traveling direction of the second light beam L2to be closer to a normal line N of the light-emitting surface T.

In the embodiment, the display device10may optionally further include a frame S. The frame S is disposed on the case BZ or the circuit board B1, and is adapted to support the first optical film F1and/or the light-guide device100. However, the invention is not limited thereto. In some embodiments, the first optical film F1, the light-guide device100, and the second optical film F2may be fixed by another support structure or frame. The invention does not intend to limit how the first optical film F1, the light-guide device100, and the second optical film F2are fixed.

Referring toFIGS. 2A and 2B,FIG. 2Ais a schematic cross-sectional view illustrating a display device according to an embodiment of the invention, andFIG. 2Bis a schematic top view illustrating a light-guide device ofFIG. 2A. The reference symbols and some contents of the embodiment shown inFIG. 1are also used in the embodiment ofFIGS. 2A and 2B, and like or similar reference symbols serve to represent like or similar components. Meanwhile, the descriptions of identical technical contents are omitted in the following. Detailed descriptions of the omitted part may be referred to the foregoing embodiment and thus will not be reiterated in the following.

In the embodiment, a light-guide device200includes a first light-guide plate210, a second light-guide plate220, a third light-guide plate230, a light deflecting structure240, and a light deflecting structure250. The first light source E1, the second light source E2, and a third light source E3are disposed on the circuit board B1.

The first light-guide plate210is located between the first light source E1and the liquid crystal panel P, and the first light-receiving surface X1is located at the first light-guide plate210and faces toward the first light source X1.

The second light-guide plate220is disposed at a side of the first light-guide plate210, such as being disposed near a left end of the first light-guide plate210. The second light-guide plate220has a bottom end and a top end. In addition, the top end of the second light-guide plate220is closer to the first light-guide plate210than the bottom end of the second light-guide plate220. In addition, the second light-receiving surface X2is located at the bottom end of the second light-guide plate220. The second light-receiving surface X2faces toward the second light source E2.

The light deflecting structure240is disposed at a side of the first light-guide plate210corresponding to the second light-guide plate220. The second light beam L2emitted by the second light source E2may travel through the second light-guide plate220, be deflected by the light deflecting structure240, be guided toward the first light-guide plate210, and then be emitted out of the light-emitting surface T of the first light-guide plate210, for example. An included angle β1is provided between a surface of the light deflecting structure240facing toward an outer side and a top surface of the second light-guide plate220or the light-emitting surface T of the first light-guide plate210. The included angle β is greater than 0 degrees and less than 90 degrees, such as 45 degrees.

The third light-guide plate230is disposed at a side of the first light-guide plate210. The third light-guide plate230and the second light-guide plate220are respectively disposed at different sides of the first light-guide plate210. The third light-guide plate230is disposed near a right end of the first light-guide plate210, for example. The third light-guide plate230has a bottom end and a top end. In addition, the top end of the third light-guide plate230is closer to the first light-guide plate210than the bottom end of the third light-guide plate230. In addition, a third light-receiving surface X3is at the bottom end of the third light-guide plate230. The third light source E3is disposed on the circuit board B1in correspondence with the third light-guide plate230. The third light-receiving surface X3faces toward the third light source E3.

The light deflecting structure250is disposed at a side of the first light-guide plate210corresponding to the third light-guide plate230. A third light beam L3emitted by the third light source E3may travel through the third light-guide plate230, be deflected by the light deflecting structure250, be guided toward the first light-guide plate210, and then be emitted out of the light-emitting surface T of the first light-guide plate210, for example. An included angle β2is provided between a surface of the light deflecting structure250facing toward an outer side and a top surface of the third light-guide plate230. The included angle β2is greater than 0 degrees and less than 90 degrees, such as 45 degrees.

The included angle between the first average light-emitting direction D1of the first light beam L1leaving the light-emitting surface T and the light-emitting surface T is the first included angle α1. An included angle between a third average light-emitting direction D3of the third light beam L3leaving the light-emitting surface T and the light-emitting surface T is a third included angle α3. The included angle α1between the first average light-emitting direction D1and the light-emitting surface T is greater than the included angle α3between the third average light-emitting direction D3and the light-emitting surface T. The included angle α3may be the same as or different from the included angle α2.

Since the first average light-emitting direction D1is different from the third light-emitting direction D3, a viewing angle of the display device20may be adjusted by choosing to turn on the first light source E1or turn on the second light source E2and/or the third light source E3. For example, when the first light source E1is turned on and the second light source E2and the third light source E3are turned off, the viewing angle of the display device20is a front viewing angle (about 0 degrees). If the third light source E3is turned on and the first light source E1is turned off, the viewing angle of the display device10may be deviated from the front and toward the side view angle. In the embodiment, the third average light-emitting direction D3and the second average light-emitting direction D2are different directions. Therefore, by turning on/off the first light source E1, the second light source E2, and the third light source E3, various viewing angles of the display device20are controlled. In some embodiments, the first light source E1, the second light source E2, and the third light source E3may be turned on at the same time to increase the brightness of a frame displayed by the display device20. Nevertheless, in another embodiment, the third average light-emitting direction D3and the second average light-emitting direction D2may be the same to enhance side light emission of a single viewing direction.

In the embodiment, the first light-guide plate210, the second light-guide plate220, the third light-guide plate230, the light deflecting structure240, and the light deflecting structure250are integrally formed. However, the invention is not limited thereto. In some embodiments, the light deflecting structure240and the first light-guide plate210or the light deflecting structure240and the second light-guide plate220may be adhered by an optical adhesive. In some embodiments, the light deflecting structure250and the first light-guide plate210or the light deflecting structure250and the third light-guide plate230may be adhered by an optical adhesive.

Referring toFIGS. 3A and 3B,FIG. 3Ais a schematic cross-sectional view illustrating a display device according to an embodiment of the invention, andFIG. 3Bis a schematic top view illustrating a light-guide device ofFIG. 3A. The reference symbols and some contents of the embodiment shown inFIGS. 2A and 2Bare also used in the embodiment ofFIGS. 3A and 3B, and like or similar reference symbols serve to represent like or similar components. Meanwhile, the descriptions of identical technical contents are omitted in the following. Detailed descriptions of the omitted part may be referred to the foregoing embodiment and thus will not be reiterated in the following.

Referring toFIGS. 3A and 3B, a light-guide device300of a display device30includes a first light-guide plate310, a light deflecting structure340, and a second light-guide plate320connected in sequence, and the light-guide device300is substantially in an L shape. What differs from the previous embodiment is that the embodiment does not include the third light-guide plate230and the light deflecting structure250. Therefore, the light-guide device300exhibits a cross-sectional shape substantially in an L shape.

Referring toFIGS. 4A and 4B,FIG. 4Ais a schematic cross-sectional view illustrating a display device according to an embodiment of the invention, andFIG. 4Bis a schematic top view illustrating a light-guide device ofFIG. 4A. The reference symbols and some contents of the embodiment shown inFIGS. 2A and 2Bare also used in the embodiment ofFIGS. 4A and 4B, and like or similar reference symbols serve to represent like or similar components. Meanwhile, the descriptions of identical technical contents are omitted in the following. Detailed descriptions of the omitted part may be referred to the foregoing embodiment and thus will not be reiterated in the following.

Referring toFIGS. 4A and 4B, a light-guide device400of a display device40includes a first light-guide plate410, a light deflecting structure440, and a second light-guide plate420connected in sequence.

The second light-guide plate420is perpendicular to the first light-guide plate410and the circuit board B1. The light deflecting structure440and the second light-guide plate420are arranged along a periphery of the first light-guide plate410to surround the first light-guide plate410, as shown inFIG. 4B. A normal projection of the second light-guide plate420on the circuit board B1surrounds a normal projection of the first light source E1on the circuit board B1. In the embodiment, since the second light-guide plate420is substantially in an annular shape, a plurality of light sources, such as the second light source E2and the third light source E3, may be disposed with respect to the light-receiving surfaces. The third light-receiving surface X3of the second light-guide plate420may face toward the third light source E3, and the third light-receiving surface X3and the second light-receiving surface X2may be located at the same or different horizontal surfaces.

FIG. 5is a partial schematic cross-sectional view illustrating a light-guide device according to an embodiment of the invention. The reference numerals and some contents in the previous embodiment are used in the embodiment ofFIG. 5, in which like or similar reference numerals indicate like or similar components, and repeated description of the same technical contents is omitted. Detailed descriptions of the omitted part may be referred to the foregoing embodiment and thus will not be reiterated in the following.

In the embodiment, a light-guide device500includes a first light-guide plate510, a light deflecting structure540, and a second light-guide plate520.

In the embodiment, a side surface W1of the light deflecting structure540facing toward an outer side and a side surface W2of the light deflecting structure540facing toward an inner side have different included angles with respect to the first light-guide plate510. For example, an included angle γ1between the side surface W1and the light-emitting surface T is greater than an included angle γ2between the side surface W2and the first light-receiving surface X1. By controlling the included angles γ1and γ2, the traveling direction of the second light beam L2is controlled.

FIG. 6is a partial schematic cross-sectional view illustrating a light-guide device according to an embodiment of the invention. In the embodiment, a light-guide device600includes a first light-guide plate610, a light deflecting structure640, and a second light-guide plate620.

In the embodiment, a side surface of the light deflecting structure640facing toward an outer side is a curved convex surface. By adjusting the curvedness of the convex surface of the light deflecting structure640, the traveling direction of the second light beam L2is controlled.

While the embodiment illustrates that the side surface of the light deflecting structure640facing toward the outer side is a smooth curved convex surface, the invention is not limited thereto. In other embodiments, the side surface of the light deflecting structure640facing toward the outer side may be in an irregular shape, such as a spline shape, or other shapes.

FIG. 7is a partial schematic cross-sectional view illustrating a light-guide device according to an embodiment of the invention. The reference numerals and some contents in the previous embodiment are used in the embodiment ofFIG. 7, in which like or similar reference numerals indicate like or similar components, and repeated description of the same technical contents is omitted. Detailed descriptions of the omitted part may be referred to the foregoing embodiment and thus will not be reiterated in the following.

In the embodiment, a light-guide device700includes a first light-guide plate710, a light deflecting structure740, and a second light-guide plate720connected in sequence. The light-guide device700optionally includes a plurality of first microstructures M1protruding from the first light-receiving surface X1. The first microstructures M1are protruding dots, for example. However, the invention is not limited thereto. The first microstructures M1may also be in a shape of semi-circles, triangles, triangular prisms, trapezoids, or other geometric shapes. In the embodiment, the light-guide device700may optionally include a plurality of microstructures M2protruding from the light-emitting surface T. The second microstructures M2are protruding dots, for example. However, the invention is not limited thereto. The second microstructures M2may also be in a shape of semi-circles, triangles, triangular prisms, trapezoids, or other geometric shapes.

The first microstructures M1and the second microstructures M2are able to facilitate the light emitting efficiency of the light-guide device700. Even though other embodiments do not illustrate the first microstructures M1and the second microstructures M2, the first microstructures M1and the second microstructures M2may also be applied in the light-guide device of any other embodiments of the invention.

FIG. 8is a partial schematic cross-sectional view illustrating a light-guide device according to an embodiment of the invention. In the embodiment, a light-guide device800includes a first light-guide plate810, a light deflecting structure840, an optical adhesive O, and a second light-guide plate820connected in sequence.

In the embodiment, the light deflecting structure840and the first light-guide plate810may be integrally formed. The light deflecting structure840is adhered to the second light-guide plate820through the optical adhesive O. In addition, the optical adhesive O may include a transparent material, for example. Accordingly, the manufacturing complexity of the light-guide device800of the embodiment may be reduced.

FIG. 9is a partial schematic cross-sectional view illustrating a light-guide device according to an embodiment of the invention. In the embodiment, a light-guide device900includes a first light-guide plate910, the optical adhesive O, a light deflecting structure940, and a second light-guide plate920connected in sequence.

In the embodiment, the light deflecting structure940and the second light-guide plate920may be integrally formed. The light deflecting structure940is adhered to the first light-guide plate910through the optical adhesive O. Accordingly, the manufacturing complexity of the light-guide device900of the embodiment may be reduced.

FIG. 10is a partial schematic cross-sectional view illustrating a light-guide device according to an embodiment of the invention. In the embodiment, a light-guide device1000includes a first light-guide plate1010, a light deflecting structure1040, and a second light-guide plate1020.

In the embodiment, the first light-guide plate1010and the second light-guide plate1020are separated. The light deflecting structure1040is a diffraction grating or a reflective layer, for example. Even though there is no other components disposed between the first light-guide plate1010and the light deflecting structure1040and between the second light-guide plate1020and the light deflecting structure1040, the invention is not limited thereto. In some embodiment, the light deflecting structure of other embodiments may also be disposed between the first light-guide plate1010and the light deflecting structure1040or between the second light-guide plate1020and the light deflecting structure1040. In other words, the light deflecting structure1040of the embodiment may be used with the light deflecting structure of other embodiments.

In view of the foregoing, according to the embodiments of the invention, the viewing angle of the display device is adjustable by choosing to turn on the first light source or turning on the second light source. For example, when the first light source is turned on and the second light source is turned off, the viewing angle of the display device is about 0 degrees. If the second light source is turned on and the first light source is turned off, the viewing angle of the display device is deviated from 0 degrees. In other words, the viewing angle of the display device may be controlled through the first light source and the second light source.