RU2617003C1 - Light guide plate and backlight device containing it - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: backlight device is configured to switch between the 3D display and the 2D display mode, comprises a light guide plate. The light guide plate comprises a substrate configured to spread the first light beam and the second light beam inside it due to total internal reflection. The first beam is introduced from one of the front surface and the rear surface of the substrate, when the 3D display mode is used, and the second beam is introduced from, at least, one of the side surfaces of the substrate, when the 2D display mode is used, the first and the second light beams have different angular distributions. The substrate also comprises a prismatic structure on an upper substrate surface and consisting of a series of the spaced prisms. The bottom substrate surface has an array of the linear grooves or protrusions.

EFFECT: reducing the total backlight device thickness, providing a simple switch between the 3D and the 2D display modes, and eliminating the shadow effect in the 3D display mode.

40 cl, 11 dwg

Description

FIELD OF THE INVENTION

The present invention relates generally to lighting techniques, in particular to a light guide plate and a backlight device comprising a light guide plate, which can be used to obtain 3D and 2D images without the need for glasses.

State of the art

Currently, 3D display devices are used in various fields of activity, such as medical imaging, games, advertisements, education, the military sphere, etc. In addition, a lot of research has been done on the display of 3D images using holographic and stereoscopic methods.

Stereoscopic methods can be classified into those in which glasses are required to be used (i.e. when polarized light and a shutter are used to allow two eyes of the user to see separate images), and those in which glasses are not required (i.e. e. the so-called autostereoscopic display, in which the display device directly divides the image to form fields of view).

Recently, with respect to autostereoscopic display devices, there has been a tendency to master the parallax barrier, which is used for the virtual creation of 3D images using stereo images. The parallax barrier includes vertical or horizontal slits formed in front of the images corresponding to the left and right eyes of the user, and allows the user to observe 3D images separately through these slots to achieve a stereoscopic effect.

At the same time, many display devices currently under construction should provide easy switching between 3D and 2D display modes without using a parallax barrier structure to satisfy all user needs.

US 8820997 B2 discloses a switchable 3D / 2D display device 1000 using a parallax barrier method to provide 3D display. As shown in FIG. 10A-B, a known display device comprises a light guide 1010 having a scattering structure 1011 on one plane thereof, which is used to form 3D images. The light guide 1010 is made of PMMA, which is colorless and transparent. Other planes of the optical fiber 1010 are machined to obtain mirror smoothness and have no elements. The light from the light sources 1013 provided at the ends of the light guide 1010 propagates between the reflective surfaces inside the light guide 1010, but when it hits the scattering structure 1011, it is diffusely reflected and emitted in the direction of the LCD 1030. Thus, by using the scattering structure 1011 provided at the locations corresponding to the slots of the parallax barrier, it is possible to obtain the same lighting state as with the parallax barrier and the backlight structure.

The unstructured portions 1012 of the light guide 1010 are flat, colorless, and transparent. Therefore, light from the light source 1020 used for 2D display passes through the unstructured portions 1012 of the light guide 1010. However, this light from the light source 1020 used for 2D display is scattered by the scattering structure 1011. This scattering by the structure 1011 does not appear in a different measure in the distribution of illumination on the LCD 1030.

Switching between 2D and 3D display modes is achieved by switching between light sources 1013 and light sources 1020. When a 2D image is required to be displayed, a controller (not shown) only activates light sources 1020. When a 3D image is required to be displayed, the controller only activates light sources 1013.

The construction shown in FIG. 10A-B provides an easy way to switch between 2D and 3D display modes without compromising resolution, light distribution, and viewing angle compared to traditional 2D display. However, the scattering structure 1011 used for the 3D display mode, which is implemented in the form of lines, can cause a shadow effect in the 2D display mode and significantly degrade the image quality.

US 7,626,643 B2 discloses a switchable parallax barrier 3D / 2D display device 1100. As shown in FIG. 11A-B, a known display device includes a display panel 1130 and a backlight system having a light source 1150 and a waveguide 1110. The waveguide 1110 includes scattering portions 1120 of scattering material. The light propagates through the waveguide 1110 due to total internal reflection, but can be scattered on the scattering sections 1120. The scattered light emerging from the waveguide 1110 through its output surface creates lines of light corresponding to the positions of the scattering sections 1110 and forming a parallax barrier used when illuminating a 3D autostereoscopic an image displayed by the display panel 1130. The intermediate sections 1140 between the scattering sections 1120 are formed of a material that can switch between a light transmission state and a dispersion state. The optical properties of the intermediate sections 1140 are controlled using electric fields. Such a display device is switchable between a 2D display mode in which the intermediate sections 1140 are scattering and the waveguide 1110 provides uniform illumination, and a 3D display mode in which the intermediate sections 1140 are light transmitting and the waveguide 1110 provides lighting in the form of light lines.

The type of switchable 3D / 2D display device shown in FIG. 11A-B, allows you to implement the required switching between 3D and 2D display modes on the same light guide plate 1110, thereby providing a reduction in thickness, but at the same time requires additional sets of column electrodes. The scattering materials used and their structure make production difficult and render such a display device inefficient, since a significant part of the light generated by the light source 1150 is lost. There is also a deterioration in image quality due to the appearance of enhanced crosstalk due to the uncontrolled scattering direction in the scattering portions 1120.

Disclosure of invention

To eliminate or mitigate one or more of the aforementioned disadvantages of the solutions known from the prior art, the present invention is described in the independent claims. Various particular embodiments of the present invention are described in the dependent claims.

The technical effects provided by the present invention are: reducing the total thickness of the backlight device by using one light guide plate for 3D and 2D display modes; providing easy switching between 3D and 2D display modes by using at least one light source for each display mode; and improving image quality by eliminating the shadow effect in 3D display using prismatic and linear structures on opposite sides of the light guide plate.

According to a first aspect of the present invention, there is provided a light guide plate. The light guide plate contains a substrate, a prismatic structure, and a linear structure. The substrate is configured to allow the propagation of the first light beam and the second light beam within itself due to total internal reflection. The first light beam is introduced from one of the front surface and the rear surface of the substrate when the 3D display mode is used, while the second light beam is introduced from at least one of the side surfaces of the substrate when the 2D display mode is used. The first and second light beams have different angular distributions. A prismatic structure is provided on the upper surface of the substrate and consists of spatially spaced rows of prisms. Each row of prisms contains a plurality of single prisms that are butt-mounted to each other. A linear structure is provided on the bottom surface of the substrate and consists of an array of linear grooves or protrusions. The prismatic structure is configured to output the first light beam from the substrate when the first light beam enters each row of prisms on the upper surface of the substrate. The linear structure is configured to output a second light beam from the substrate when the second light beam enters each linear groove or protrusion on the lower surface of the substrate.

In some embodiments, the rows of prisms of the prismatic structure are periodically or non-periodically spatially spaced on the upper surface of the substrate.

In some embodiments, the grooves or protrusions of the linear structure are periodically or non-periodically spatially spaced on the bottom surface of the substrate.

In some embodiments, the rows of prisms of the prismatic structure are parallel to the direction of propagation of the first light beam or are located at an arbitrary angle relative to the direction of propagation of the first light beam.

In some embodiments, the grooves or protrusions of the linear structure are perpendicular to the propagation direction of the second light beam or are located at an arbitrary angle relative to the propagation direction of the second light beam.

In one embodiment, the substrate, prismatic structure, and linear structure are made of PMMA and / or other optically transparent material, such as, for example, glass. The substrate, prismatic structure and linear structure can be made as one unit.

In one embodiment, a prismatic structure is provided on the upper surface of the substrate by etching, printing, gluing, molding, cutting, or any combination thereof.

In one embodiment, a linear structure is provided on the bottom surface of the substrate by etching, printing, or a combination thereof.

In one embodiment, the width of the substrate is constant, or the substrate has a variable width.

In one embodiment, the prisms in each row of prisms of the prismatic structure are linearly end-to-end with each other. In another embodiment, the prisms in each row of the prisms of the prismatic structure are end-to-end, but offset relative to each other, thereby forming a zigzag line.

In one embodiment, the spatial diversity period and the width of each row of prisms of the prismatic structure are selected in accordance with the characteristics of the light source illuminating the substrate with the first light beam. The width of each row of prisms can be constant or variable. If the width is variable, the width of each row of prisms may increase from said one of the front and back surfaces of the substrate onto which the first light beam falls, to the other of the front and back surfaces of the substrate. The width of each row of prisms of the prismatic structure can also vary continuously or discretely from the prism to the prism.

In one embodiment, the base of each prism in each row of prisms of the prismatic structure has a constant or variable width.

In one embodiment, the width and depth / height of each groove or protrusion in the linear structure are selected in accordance with the characteristics of the light source illuminating the substrate with a second light beam. The width and / or depth / height of each groove or protrusion in the linear structure may be constant or different. The width and / or depth / height of each groove or protrusion in the linear structure may also vary along the length of the groove or protrusion.

According to a second aspect of the present invention, there is provided a backlight device. The backlight device is configured to switch between the 3D display mode and the 2D display mode. The backlight device comprises a light guide plate according to a first aspect of the present invention, at least one first lighting module, at least one second lighting module, at least one redirection film and at least one reflective film. Said at least one first lighting module is configured to emit a first light beam in the direction of one of a front surface and a rear surface of the substrate of the light guide plate. Said at least one second lighting module is configured to emit a second light beam in the direction of at least one of the side surfaces of the substrate of the light guide plate. The first and second light beams have different angular distributions. Said at least one redirection film is provided above the upper surface of the substrate. Said at least one reflective film is provided below the bottom surface of the substrate. When the 3D display mode is selected, said at least one first lighting module is turned on, said at least one second lighting module is turned off, and said at least one redirection film is adapted to redirect a first light beam outputted from the substrate through the prismatic structure, in the direction of the eye of the observer. When the 2D display mode is selected, said at least one first lighting module is turned off, said at least one second lighting module is turned on, and said at least one reflective film is capable of reflecting a second beam of light output from the substrate through a linear structure, and changing the angular distribution of the second light beam to allow the second light beam to pass through the substrate and said at least one redirection film into the eye of the observer.

In one embodiment, said at least one first lighting module consists of at least one first light source and at least one first light conversion module, and said at least one second lighting module consists of at least one second light source and at least one second light conversion module. Said at least first light conversion module is adapted to collimate, homogenize and angularly transform the light emitted by said at least one first light source, and to introduce the converted light as a first light beam into the substrate. Said at least one second light conversion module is adapted to collimate, homogenize and angularly convert the light emitted by said at least one second light source, and to introduce the converted light as a second light beam into the substrate.

In one embodiment, each of said at least one first light source and said at least one second light source is made in the form of one or more LEDs, laser diodes, lamps, or any combination thereof.

In one embodiment, said at least one first light conversion module comprises at least one collimating array, at least one homogenizing film, and at least one redirecting cube. The collimating array can be made in the form of a set of separate or combined collimators. The homogenizing film can be made in the form of a film with microspherical or microcylinder lenses. The homogenizing film may be in the form of a diffuser to shape the light beam. The redirecting cube can be made in the form of a cube having a symmetric or asymmetric prismatic structure.

In one embodiment, said at least one second light conversion unit is configured as a collimating cube with parallel or non-parallel surfaces.

In one embodiment, said at least one redirection film has an array of symmetric or asymmetric microprisms.

In one embodiment, the backlight device further comprises a film with Fresnel lenses provided over said at least one redirecting film and configured to focus the first and second light beams from said at least one redirecting film in an observer plane. A film with Fresnel lenses may have a radial or cylindrical structure.

In one embodiment, the reflective film is made in the form of a film with convex or concave microspherical or micropyramidal lenses. In another embodiment, the reflective film is made in the form of a reflective diffuser with a Lambert angular distribution.

Other features and advantages of the present invention will be apparent after reading the following detailed description and after viewing the accompanying drawings.

Brief Description of the Drawings

The essence of the present invention is explained below with reference to the accompanying drawings, in which:

FIG. 1 is a diagram illustrating a perspective view of a switchable 3D / 2D backlight device in accordance with one exemplary embodiment of the present invention;

FIG. 2A-B are diagrams illustrating top and bottom views of a light guide plate with prismatic and linear structures for extracting light;

FIG. 3A-D are diagrams illustrating general views of the upper surface of a light guide plate containing differently located prismatic structures;

FIG. 4A-B are diagrams illustrating general views of a single prism in a prismatic structure located on an upper surface of a light guide plate;

FIG. 5 is a diagram illustrating a transverse view of one linear groove or protrusion in a linear structure located on a lower surface of a light guide plate;

FIG. 6 is a diagram illustrating a transverse view of a backlight device based on a single light guide plate operating in a 3D display mode;

7 is a diagram illustrating one example of a lighting module used for a 3D display mode;

FIG. 8A-C are diagrams illustrating transverse views of a lighting module used for a 3D display mode, and a general view of one collimator in a collimating array that is part of a lighting module;

FIG. 9 is a diagram illustrating a transverse view of a backlight device based on one light guide plate operating in a 2D display mode;

FIG. 10A-B are diagrams illustrating a transverse view of one type of switchable 3D / 2D display device of the prior art;

FIG. 11A-B are diagrams illustrating a transverse view of another type of switchable 3D / 2D display device of the prior art.

The implementation of the invention

Various embodiments of the present invention are described in more detail below with reference to the accompanying drawings. However, the present invention can be implemented in many other forms and should not be construed as being limited by any particular structure or function as described in the following description. In contrast, these embodiments are provided in order to make the description of the present invention detailed and complete. Based on the present description, it will be obvious to a person skilled in the art that the scope of the present invention covers any embodiment of the present invention that is disclosed herein, regardless of whether this embodiment is implemented independently or in conjunction with any other embodiment of the present invention . For example, the device disclosed herein may be practiced by using any number of embodiments provided herein. In addition, it should be understood that any embodiment of the present invention can be implemented using one or more of the elements presented in the attached claims.

The word “exemplary” is used herein to mean “used as an example or illustration”. Any embodiment described herein as “exemplary” need not be construed as preferred or having an advantage over other embodiments.

In addition, terminology associated with the direction, such as “front”, “back”, “upper”, “lower”, “side”, etc., is used with reference to the orientation of the described figures. Since the components of the embodiments of the present invention can be arranged in different orientations, terminology associated with the direction is used for purposes of illustration and not limitation. It should be understood that other embodiments may be used and structural or logical substitutions may be made without departing from the scope of the present invention.

FIG. 1 shows a perspective view of a switchable parallax barrier 3D / 2D backlight device 100 in accordance with one exemplary embodiment of the present invention. The backlight device 100 is configured to switch between a 3D display mode and a 2D display mode. As shown, the backlight device 100 comprises a light guide substrate 110, a first lighting module 120, a second lighting module 130, a redirection film 140, a reflection film 150, and a film 160 with Fresnel lenses. Those skilled in the art will appreciate that the present invention is not limited by the number of components shown in FIG. 1, and, if required, the backlight device 100 may further comprise two or more first lighting modules 120, second lighting modules 130, redirection films 140 and / or reflection films 150. The only limitation is that the backlight device 100 only uses one light guide substrate 110, which is necessary to ensure a decrease in its thickness. The number of other structural elements of the backlight device 100 may vary depending on specific applications.

In the embodiment shown in FIG. 1, the first lighting module 120 is used for the 3D display mode and consists of at least one light source 121 and at least one light conversion module 122. The second lighting module 130 is used for the 2D display mode and consists of at least one light source 131 and at least one light conversion module 132. The first lighting module 120 is configured to emit a first light beam in the direction of one of the front surface and the rear surface of the light guide substrate 110, while the second lighting module 130 is configured to emit a second light beam in the direction of at least one of the side surfaces of the light guide substrate 110. Since the lighting modules 120 and 130 are used for 3D and 2D display modes, respectively, the first and second light beams emitted by the lighting modules 120 and 130 must have different angular distributions. As will be shown below, the light guide substrate 110 is provided with a prismatic structure 111 on its upper surface for extracting the first light beam in 3D display mode and a linear structure 112 on its lower surface for extracting the second light beam in 2D display mode. It should be noted that the term “light guide plate” as used herein means a combination of the light guide substrate 110 together with the prismatic and linear structures 111, 112. A redirecting film 140 is provided above the light guide substrate 110, and a reflective film 150 is provided under the light guide substrate 110. The film 160 with Fresnel lenses is an optional structural element and is provided above the redirecting film 140.

Light source 121 may be implemented as one or more light emitting diodes (LEDs), laser diodes, llamas, or any combination thereof. In preferred embodiments, the light source 121 is implemented as one or more LEDs for emitting uncollimated unpolarized light or one or more laser diodes for emitting polarized highly collimated light. In the same preferred embodiments, the light conversion module 122 is configured to collimate, homogenize, and angularly transform the light emitted by the light source 121, and to introduce the converted light as the first light beam into the light guide substrate 110.

The light source 131 may also be implemented as one or more LEDs or llamas for emitting uncollimated unpolarized light or one or more laser diodes for emitting polarized highly collimated light. Preferably, the light conversion unit 132 is configured to collimate, homogenize, and angularly transform the light emitted by the light source 131 and to introduce the converted light as a second light beam into the light guide substrate 110.

The transfer film 140 is configured to redirect the first beam of light emitted by the first lighting module 120 and removed from the light guide substrate 110 by the prismatic structure 111, normal to the upper surface of the Fresnel lens film 160, if used, or directly in the direction of the observer's eyes. A film 160 with Fresnel lenses is used to focus the first light beam (as well as the second light beam in the case of the 2D display mode) from the redirecting film 140 in the plane of the observer.

The reflective film 150 is configured to reflect a second light beam outputted from the substrate 110 through the linear structure 112, and change the angular distribution of the second light beam to allow the second light beam to pass through the substrate 110 and the redirection film 140 (and the film 160 with Fresnel lenses, if it applied) in the direction of the observer's eyes.

Switching between 3D and 2D display modes is realized by switching between the first lighting module 120 and the second lighting module 130. In the 3D display mode, the light source 121 of the first lighting module 120 is turned on, while the light source 131 of the second lighting module 130 is turned off. In the 2D display mode, the opposite situation is observed.

The light guide substrate 110 of the backlight device 100 is configured to propagate the first and second light beams within themselves due to the effect of total internal reflection. The design of the light guide plate will now be described in more detail with reference to FIG. 2A-B. As noted above, the light guide plate includes a light guide substrate 110 (hereinafter referred to as “the substrate” for simplicity), a prismatic structure 111 provided on the upper surface of the substrate 110, and a linear structure 112 provided on the lower surface of the substrate 110. Substrate 110, prismatic structure 111 and linear structure 112 may be made of PMMA and / or glass, and / or other optically transparent material. In addition, the substrate 110, the prismatic structure 111, and the linear structure 112 may be integrally formed.

FIG. 2A illustrates a prismatic structure 111 configured to partially output a first light beam propagating within the substrate 110 (in the case of a 3D display mode) from the substrate 110 in the direction of the redirection film 140 when the first light beam falls on the prismatic structure 111. The prismatic structure 111 consists from spatially spaced rows of 210 prisms. Each row 210 of prisms contains a plurality of individual prisms 211 located end-to-end with each other. A first light beam from the first illumination module 120 (i.e., from the light source 121) is introduced through the front surface of the substrate 110. The upper surface and lower surface of the substrate 110 are optically polished. The rows of prisms 210 are separated from each other on the upper surface of the substrate 110 by unstructured zones 212. If the first light beam introduced from the first lighting module 120 into the substrate 110 enters the unstructured zones 212, it does not violate the effect of total internal reflection and propagates inside the substrate 110 without changes. At the same time, if the first light beam introduced from the lighting module 120 into the substrate 110 falls on a row of prisms 210, it is partially removed from the substrate 110 due to the violation of the effect of total internal reflection. In this case, the prism rows 210 are linear slits for the display mode based on the parallax barrier, and the first light beam output from the substrate 110 through the prism rows 210 forms illumination with an autostereoscopic display effect. At the same time, the unstructured zones 212 form barriers for the display mode based on the parallax barrier (since the second light beam entering the zones 212 remains inside the substrate 110 by maintaining the effect of total internal reflection). The prismatic structure 111 can be provided on the upper surface of the substrate 110 by means of etching, printing, gluing, molding, cutting, or any combination thereof.

FIG. 3A-D show various exemplary embodiments of a prismatic structure 111.

The prism rows 210 in the prismatic structure 111 may be parallel to the propagation direction of the first light beam, as shown in FIG. 3A, or can be rotated by a certain angle relative to the direction of propagation of the first light beam, as shown in FIG. 3B-D. Each prism 211 in the row 210 of prisms of the prismatic structure 111 can be oriented in the direction of propagation of the first light beam, as shown in FIG. 3A and 3C, or may be rotated through a certain angle in accordance with the general direction of the row in the prismatic structure 111, as shown in FIG. 3B and 3D. The prisms 211 in the rows 210 of the prisms of the prismatic structure 111 can be linearly end-to-end with each other, as shown in FIG. 3A, 3B and 3D, or with any offset to form zigzag lines, as shown in FIG. 3C. The prismatic structure 111 is characterized by basic parameters such as a period 310 between rows of 210 prisms and a width of 320 for each row 210 of prisms. The period 310 is selected so as to provide the possibility of applying a further algorithm for compiling an image and achieving an autostereoscopic image in the process of lighting and image compilation. In general, period 310 is constant, but may be variable according to the requirements of the algorithm. The width 320 is selected in accordance with the width of the linear light sources illuminating the composite image on the panel determined by the image compilation algorithm. In general, the width 320 is constant, but may be variable according to the requirements of the algorithm or the need to improve the efficiency and uniformity of light extraction from the substrate 110. If the width 320 is changed, the width 320 generally increases from the front surface to the rear surface of the substrate 110 (in accordance with orientation shown in Fig. 3A-D).

FIG. 4A-B show the general diagrams of each prism 211 in the prismatic structure 111. As shown in these figures, the width 320 of each row 210 of the prisms can vary continuously or discretely from the prism to the prism depending on the applicable algorithm requirements, the distribution of the series of prisms and production technology. The width 320 is determined by the width 410 of each prism 211 located at the design point of the row of prisms in the prismatic structure 111. The main parameters of each row 211 in the prismatic structure 111 are determined so that the first light beam is removed from the substrate 110 with high efficiency and uniformly, but with slight deterioration of its inherent light parameters, such as angular distribution. Width 410 may be constant for one given prism 211, as shown in FIG. 4A, or a variable with an initial value of 4101 and an end value of 4102, as shown in FIG. 4B, in accordance with the applicable conditions. The width 410 defines a portion of the first light beam passing through the lower surface 411 of each prism and, accordingly, emerging from the substrate 110 due to the violation of the effect of total internal reflection on the surface 412 of the prism. To disrupt the effect of total internal reflection, the surface 412 is oriented at a certain angle exceeding the angle of total internal reflection between the first light beam propagating inside the substrate 110 and the surface 412. The angular position of the surface 412 is determined by the first angle 413 at the base, which is selected depending on the parameters of the first the lighting module 120, and thus the propagation parameters of the first light beam inside the substrate 110. In general, the first corner 413 at the base is also set in accordance with Glov prismatic surface structure redirects the film 140 (which will be discussed below) to ensure accurate redirects the first light beam output from the substrate 110, on plane normal to the observer.

The second corner 414 at the base is set so as to obtain a uniform vertical angular distribution of the output first light beam after passing through the surface 412. The length of the prism 415 is selected so as to provide high-quality uniform lines of the output first light beam, and can be further determined by the structure of the redirection film 140, the design of the display panel and the requirements of the algorithm, especially in the case of zigzag rows of prisms in the prismatic structure 111.

For the cases of the embodiments described above with reference to FIG. 3B and 3D, prism 211 may be implemented in the form of an unusual prism having a modified shape in which the sides along the propagation direction are not perpendicular to the sides of the prism and rotated through an angle 416 to compensate for possible light deviations. Other marked parameters, such as the upper angle 417 and the height 418 of the prism, are dimensions defined in accordance with angles 413, 414 and a length of 415.

Thus, the parameters of the prism 311 are related to the characteristics of the first light beam (from the light source 121) propagating within the substrate 110.

Returning to FIG. 2B, a linear structure 112 is shown as being provided on the lower surface of the substrate 110 and consisting of an array of linear grooves or protrusions 220. The linear structure 112 can be provided on the lower surface of the substrate 110 by etching, printing, or a combination thereof. The second light beam is introduced by the second lighting module 130 (ie, the second light source 131) into the substrate 110 with at least one of the side surfaces of the substrate 110. The linear structure 112 is configured to partially output the second light beam (in the case of the 2D display mode) from the substrate 110, when a second light beam enters each groove or protrusion on the lower surface of the substrate 110. A second light beam partially removed from the substrate 110 through the linear structure 112 is directed to the redirecting film 150. Similar to the first beam with The 3D image used when the second light beam enters the unstructured zones 221 between the grooves or protrusions 220, it does not violate the effect of total internal reflection and propagates further inside the substrate 110.

FIG. 5 is a transverse view of one linear groove or protrusion 220. The linear structure 112 is characterized by the following parameters: the period between the linear grooves or protrusions, a width of 510, a height of 520, and a length of 530 of each groove or protrusion. The period between the linear grooves or protrusions may be constant or variable. The period is chosen in such a way as to ensure uniform lighting. The width 510 and height 520 of each groove or protrusion 220 in the linear structure 112 may also be constant or variable. If the width 510 and the height 520 are variable, these parameters can be varied along the length 530 to ensure uniform extraction of the second light beam along all directions of the substrate 110. It should be noted that the period, width 510, and height 520 can vary linearly, randomly, or in any other suitable way . In addition, each of the grooves or each of the protrusions of the linear structure may be perpendicular to the direction of propagation of the second light beam or may be located at an arbitrary angle relative to the direction of propagation of the second light beam.

A functional illumination diagram in 3D display mode is illustrated in FIG. 6. The first lighting module 120 is located close to the surface of the substrate 110 for introducing the first light beam from the light source 121 (after passing the light conversion module 122) into the substrate 110. If the light source 121 is implemented as one or more LEDs, the light conversion module 122 is implemented in the form of a combination of a collimating array 123, ensuring the collimation of light from the LED due to the use of the effect of total internal reflection, a homogenizing film 124, ensuring the homogenization of collimated light from the collimating mass siva 123, a redirection cube 125, which provides additional mixing of light as a zone component of the front panel and redirects the light to increase the efficiency and uniformity of further extraction of light from the substrate 110. Different types of this type of light conversion module 122 are illustrated in FIG. 7 and 8A-C. Again, it should be noted that light from the first lighting module 120 is introduced into the substrate 110 as a first light beam.

The collimating array 123 can be implemented as a series of combined or separate collimators for each light source in the array of light sources 121 or as any other module with a different structure, but with the same functionality, converting point-distributed non-collimated light into a uniform spatial distribution of collimated light at the exit.

The homogenizing film 124 is configured to convert the angular distribution of the input light into the desired angular distribution for further input to the substrate 110 and lighting. The homogenizing film 124 can be implemented as a lens-raster film with a micro-cylindrical structure, a film with a microspherical structure with convex and concave lens arrays, a diffuser to shape the light beam, capable of scattering light for only one of two or both of the vertical and horizontal axes, or can be implemented in the form of any other film with a different structure, but with the same functionality of manipulating light by changing the direction of its energy ui.

The redirecting cube 125 is configured to split the input light into several interdependent directions to increase the uniformity and efficiency of further extraction of light from the substrate 110. The redirecting cube 125 can be implemented as a cube having a symmetric or asymmetric prismatic structure, or in the form of any other cube having different structure, but the same functionality of manipulating light by splitting the light into several interdependent directions. The redirection cube 125 may be implemented with an increased length along the direction of light propagation in order to function similarly to the zonal component of the front panel.

As shown in FIG. 8A-B, which are a top view and a side view of the light conversion unit 122, respectively, uncollimated light from periodically spatially separated light sources 121 is reflected on and introduced into the front surface of each collimator in the collimating array 123. Inside, the light is collimated due to the effect of total internal reflection on the side surfaces 1231 for horizontal collimation and the upper and lower surfaces 1232 for vertical collimation. The cylindrical surface 1233 provides additional required collimation in the horizontal direction, compensating for the length of the collimating array 123.

The collimated light from the collimating array 123 passes through the homogenizing film 124, implemented as a lens-raster film with vertically oriented micro-cylindrical surfaces 1241. The parameters of the homogenizing film 124 are selected based on the key angular characteristics of the input and desired output light.

Then, the light from the homogenizing film 124 is split in two directions on a redirecting cube 125 having a symmetrical microprismatic surface 1251 containing elongated microprisms located with a vertical period. Light is reflected on the prismatic surface 1251 with an additional angular displacement and passes through the cube 125, being redirected in two symmetrical directions. The vertical and horizontal dimensions of all the components of the light conversion module 122 are additionally set based on the dimensions of the light source 121 and the front surface of the substrate 110 (which is illuminated by the light source 121). All components in the light conversion module 122 are end-to-end with each other without air gaps or with a small air gap to reduce the total thickness of the first lighting module 120.

A general view of one collimator in collimating array 123 is shown in FIG. 8C. The horizontal width 1234 is selected based on the horizontal size of one lighting area of the light source 121 in accordance with the principle described above, and the vertical height 1235 is selected in a similar manner. The horizontal width 1236 is set based on a pre-calculated number of light sources in the array of light sources 121 and its corresponding period, which is also calculated in accordance with the size of the front surface of the substrate 110 (which is illuminated by the light source 121). The length 1237 is set so as to provide sufficient collimation of uncollimated light with a wide angular distribution from light sources 121; in general, it is calculated from the condition of ensuring uniform spatial and angular distribution of collimated light. The length of 1238 is set in accordance with the production capabilities and general requirements for the length of the collimator. The radius 1239 for the cylindrical surface 1233 is calculated so as to obtain a component with a focal length sufficient for additional collimation. All parameters for a single collimator in collimating array 123 are variable, and the design shown in FIG. 8A-C is an example only and may be modified to achieve the same light output characteristics.

The proper implementation of the light conversion module 122 allows the desired angular and spatial distribution of light to be provided for further input into the substrate 110 and efficient and uniform light extraction for high-quality 3D display lighting.

Returning to FIG. 6, the first light beam removed from the substrate 110 through the prismatic structure 111 reaches the redirection film 140 located above the substrate 110. The redirection film 140 is configured to redirect the first light beam through itself so that the first light beam falls normal to the upper surface redirection film 140.

The transfer film 140 may be implemented as a film with a prismatic structure 141 on its lower surface. In this case, the prismatic structure 141 is configured to redirect the first light beam due to the effect of total internal reflection. The first light beam extracted from the substrate 110 through the prismatic structure 111 reaches one of the two sides of each prism in the prismatic structure 141. After refraction on the aforementioned one of the two sides of each prism in the prismatic structure 141, the first light beam hits the opposite side, where it is reflected due to the effect of total internal reflection, it passes through the rest of the redirecting film 140 along the normal to its upper surface. The transfer film 140 may also be implemented as an optical film with a different structure, but with the same functionality.

After passing through the redirection film 140, a first light beam propagates to the Fresnel lens structure 161 provided on the lower surface of the Fresnel lens film 160. A film 160 with Fresnel lenses is used to focus the incident first light beam (as well as the incident second light beam in the case of 2D display mode) from the redirecting film 140 in the observer plane. The parameters of each Fresnel lens, such as radius or curvature, are selected so as to focus the light beam in the plane of the observer at the required distance from the display.

Thus, the main observation area of the parallax barrier is formed in the plane of the observer. The parallax barrier effect is achieved mainly by illuminating the pixel panel with a linear light pattern from the substrate 110. The linear light pattern is obtained because the prismatic structure 111 is located periodically or non-periodically, forming lines of light.

A functional lighting diagram in 2D display mode is illustrated in FIG. 9. As shown, two second lighting modules 130 are located on the side surfaces of the substrate 110 (and along the length of the substrate 110) to allow light from light sources 131 to enter the substrate 110. Instead of two lighting modules 130, only one or more two lighting modules can be used depending on specific applications.

As noted above, the lighting module 130 consists of a light source 131 and a light conversion module 132. The light conversion module 132 may be implemented with an increased length along the light propagation direction to function as a zone component of the front panel. The light emitted by the light source 131 passes through the light conversion unit 132 and, being subjected to angular conversion, is introduced through the side surfaces into the substrate 110 as a second light beam. A second light beam propagates within the substrate 110 as in a waveguide.

The second light beam extracted from the substrate 110 through the linear structure 112 is oriented not normal, but with a pre-calculated angular divergence, and falls on the reflective film 150. The reflective film 150 is configured to reflect and change the angular distribution of the second light beam so that a second beam of light passed through the redirecting film 140 normal to the upper surface of the Fresnel lens film 160. Reflective film 150 can be implemented as a reflective structured film with microspherical convex or concave lenses, a reflective diffuser, reflective films with different structures, but with the same functionality, or even in the form of an arrangement of selected films with the same complex functionalities. A second light beam incident on the surface 151 is reflected upward with a changed angular distribution of light to pass through the redirection film 140.

Thus, the above method allows for uniform spatial and sufficient angular distribution of light for further illumination of the LCD with a wide field of view in the case of the 2D display mode. The mentioned characteristics are largely achieved due to the structure and location of the linear structure 112 on the lower surface of the substrate 110.

In general terms, the present invention provides a backlight device 100 configured to switch between a 3D display mode and a 2D display mode. When the 3D display mode is selected, the first lighting module 120 is turned on, the second lighting module 130 is turned off, and the transfer film 140 is configured to redirect the first beam of light output from the substrate 110 through the prismatic structure 111 towards the observer's eyes. When the 2D display mode is selected, the first lighting module 120 is turned off, the second lighting module 130 is turned on, and the reflection film 150 is configured to reflect a second beam of light outputted from the substrate 110 through the linear structure 112, and change the angular distribution of the second light beam to allow passage a second beam of light through the substrate 110 and the redirecting film 140 in the direction of the eye of the observer.

Although exemplary embodiments of the present invention have been disclosed herein, it should be noted that in these embodiments of the present invention, any various changes and modifications may be made without departing from the scope of legal protection that is determined by the appended claims. In the appended claims, reference to the singular does not exclude the presence of a plurality of such elements unless explicitly stated otherwise.

Claims (57)

1. The light guide plate containing: a substrate configured to permit the propagation of the first light beam and the second light beam within itself due to total internal reflection, wherein the first light beam is introduced from one of the front surface and the rear surface of the substrate when the 3D display mode is used, and the second light beam is introduced from at least at least one of the side surfaces of the substrate when the 2D display mode is used, wherein the first and second light beams have different angular distributions; a prismatic structure provided on the upper surface of the substrate and consisting of spatially spaced rows of prisms, wherein each row of prisms contains a plurality of single prisms that are end-to-end to each other; and a linear structure provided on the bottom surface of the substrate and consisting of an array of linear grooves or protrusions; wherein the prismatic structure is configured to output the first light beam from the substrate when the first light beam enters each row of prisms on the upper surface of the substrate; and the linear structure is configured to output a second light beam from the substrate when the second light beam enters each linear groove or protrusion on the lower surface of the substrate. 2. The light guide plate according to claim 1, in which the rows of prisms of the prismatic structure are periodically spatially spaced on the upper surface of the substrate. 3. The light guide plate according to claim 1, wherein the rows of prisms of the prismatic structure are non-periodically spatially spaced on the upper surface of the substrate. 4. The light guide plate according to claim 1, wherein the grooves or protrusions of the linear structure are periodically spatially spaced on the lower surface of the substrate. 5. The light guide plate according to claim 1, wherein the grooves or protrusions of the linear structure are spatially spaced non-periodically on the lower surface of the substrate. 6. The light guide plate according to claim 1, in which the rows of prisms of the prismatic structure are parallel to the direction of propagation of the first light beam or are located at an arbitrary angle relative to the direction of propagation of the first light beam. 7. The light guide plate according to claim 1, wherein the grooves or protrusions of the linear structure are perpendicular to the direction of propagation of the second light beam or are located at an arbitrary angle relative to the direction of propagation of the second light beam. 8. The light guide plate according to claim 1, wherein the substrate, prismatic structure, and linear structure are made of PMMA and / or other optically transparent material. 9. The light guide plate according to claim 1, wherein the substrate, the prismatic structure, and the linear structure are integrally formed. 10. The light guide plate according to claim 1, wherein the prismatic structure is provided on the upper surface of the substrate by means of etching, printing, gluing, molding, cutting, or any combination thereof. 11. The light guide plate according to claim 1, wherein the linear structure is provided on the lower surface of the substrate by means of etching, printing, or a combination thereof. 12. The light guide plate according to claim 1, in which the width of the substrate is constant. 13. The light guide plate according to claim 1, in which the substrate has a variable width. 14. The light guide plate according to claim 1, wherein the prisms in each row of the prisms of the prismatic structure are linearly end-to-end to each other. 15. The light guide plate according to claim 1, in which the prisms in each row of the prisms of the prismatic structure are end-to-end, but offset from each other, thereby forming a zigzag line. 16. The light guide plate according to claim 1, in which the period of spatial diversity and the width of each row of prisms of the prismatic structure are selected in accordance with the characteristics of the light source illuminating the substrate with the first light beam. 17. The light guide plate according to claim 16, wherein the width of each row of prisms is constant. 18. The light guide plate according to claim 16, wherein the width of each row of prisms is variable. 19. The light guide plate according to claim 18, wherein the width of each row of prisms increases from said one of the front and rear surfaces of the substrate, on which the first light beam incident, to the other of the front and rear surfaces of the substrate. 20. The light guide plate according to claim 16, in which the width of each row of prisms of the prismatic structure varies continuously or discretely from the prism to the prism. 21. The light guide plate according to claim 1, wherein the base of each prism in each row of prisms of the prismatic structure has a constant width. 22. The light guide plate according to claim 1, wherein the base of each prism in each row of prisms of the prismatic structure has a variable width. 23. The light guide plate according to claim 1, wherein the width and depth / height of each groove or protrusion in the linear structure are selected in accordance with the characteristics of the light source illuminating the substrate with a second light beam. 24. The light guide plate according to claim 1, wherein the width and / or depth / height of each groove or protrusion in the linear structure is constant. 25. The light guide plate according to claim 1, in which the width and / or depth / height of each groove or protrusion in the linear structure are different. 26. The light guide plate of claim 25, wherein the width and / or depth / height of each groove or protrusion in the linear structure varies along the length of the groove or protrusion. 27. A backlight device configured to switch between a 3D display mode and a 2D display mode, the device comprising: light guide plate according to one of paragraphs. 1-26; at least one first lighting module, configured to emit a first light beam in the direction of one of the front surface and the rear surface of the substrate of the light guide plate; at least one second lighting module configured to emit a second light beam in the direction of at least one of the side surfaces of the substrate of the light guide plate, the first and second light beams having different angular distributions; at least one redirection film provided above the upper surface of the substrate; and at least one reflective film provided below the bottom surface of the substrate; wherein when the 3D display mode is selected, said at least one first lighting module is turned on, said at least one second lighting module is turned off, and said at least one redirection film is configured to redirect a first light beam outputted from the substrate through the prismatic structure, in the direction of the observer's eyes; when the 2D display mode is selected, said at least one first lighting module is turned off, said at least one second lighting module is turned on, and said at least one reflective film is configured to reflect a second beam of light output from the substrate through a linear structure, and changing the angular distribution of the second light beam to allow the second light beam to pass through the substrate and said at least one redirection film into the eye of the observer. 28. The backlight device according to p. 27, in which: said at least one first lighting module consists of at least one first light source and at least one first light conversion module; said at least one second lighting module consists of at least one second light source and at least one second light conversion module; wherein said at least first light conversion module is configured to collimate, homogenize, and angularly transform the light emitted by said at least one first light source, and to introduce the converted light as a first light beam into the substrate; and said at least one second light conversion module is configured to collimate, homogenize, and angularly transform the light emitted by said at least one second light source, and to introduce the converted light as a second light beam into the substrate. 29. The backlight device according to p. 28, in which each of said at least one first light source and said at least one second light source is made in the form of one or more LEDs, laser diodes, lamps, or any combination thereof. 30. The backlight device according to claim 28, wherein said at least one first light conversion module comprises at least one collimating array, at least one homogenizing film, and at least one redirection cube. 31. The backlight device according to p. 30, in which the collimating array is made in the form of a set of separate or combined collimators. 32. The backlight device according to claim 30, wherein the homogenizing film is made in the form of a film with microspherical or microcylinder lenses. 33. The backlight device according to claim 30, wherein the homogenizing film is made in the form of a diffuser to shape the light beam. 34. The backlight device according to claim 30, wherein the redirection cube is made in the form of a cube having a symmetric or asymmetric prismatic structure. 35. The backlight device according to claim 28, wherein said at least one second light conversion module is made in the form of a collimating cube with parallel or non-parallel surfaces. 36. The backlight device according to claim 27, wherein said at least one redirection film has an array of symmetric or asymmetric microprisms. 37. The backlight device according to claim 27, further comprising a film with Fresnel lenses provided above said at least one redirecting film and configured to focus the first and second light beams from said at least one redirecting film in an observer plane. 38. The backlight device according to claim 37, wherein the film with Fresnel lenses has a radial or cylindrical structure. 39. The backlight device according to p. 27, in which the reflective film is made in the form of a film with convex or concave microspherical or micropyramidal lenses. 40. The backlight device according to p. 27, in which the reflective film is made in the form of a reflective diffuser with a Lambert angular distribution.

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