WO2013181910A1 - Liquid crystal lens and 2d-3d switchable three-dimensional display device - Google Patents

Description

 Liquid crystal lens and 2D-3D switchable stereo display device

 Embodiments of the present invention relate to a liquid crystal lens and a 2D-3D switchable stereoscopic display device. Background technique

 2D displays cannot directly display stereoscopic images. The key to being able to see a 3D stereoscopic image is that the two eyes of the person have a pupil distance of about 60 mm to produce a difference in viewpoint. The two images with "binocular parallax" become a pair of "stereoscopic image pairs", which have a three-dimensional effect through the fusion of the human visual cortex.

 The 3D display is divided into a tree eye type and a glasses type. The glasses type mainstream technology includes a shutter glass technique and a pattern retard, and the eye type mainly includes a parallax barrier grating, a cylindrical lens grating, and a liquid crystal lens ( LC Lens) grating technology. In the eye-type grating, since the transmittance of the LC lens is high and the switching of 2D-3D can be realized, it will become the mainstream of the 3D display of the eye.

 In the LC lens, one of the more commonly used techniques is a polarization-switching curved liquid crystal lens method, and its display principle is shown in FIG. In FIG. 1, a controllable twisted nematic liquid crystal cell 9 is disposed between the display panel 7 and the liquid crystal lens 10. The method uses an additional controllable twisted nematic liquid crystal cell (TN Cell) to change the light emitted by the display panel. The linear polarization state, and the light of different linear polarization states is different through the refractive index of the anisotropic liquid crystal: when the refractive index of the liquid crystal matches the refractive index of the concave lens of the polymer, the light is directly transmitted to realize 2D display; When the refractive index of the polymer concave lens does not match, the liquid crystal polymer layer functions as a convex lens to realize 3D display. One of the disadvantages of this method is that an additional TN cell device is required, and the display box thickness is increased and the cost is also significantly increased. Summary of the invention

 Embodiments of the present invention provide a liquid crystal lens and a 2D-3D switchable stereoscopic display device, which do not require an additional TN cell device, and enhance the display effect of the stereoscopic display device.

An embodiment of the present invention provides a liquid crystal lens, including: a first substrate, a first electrode formed on the first substrate; a second substrate; a second electrode formed on the second substrate; a polymer layer and a liquid crystal layer between an electrode and the second electrode, the polymer layer and the liquid Forming an arc-shaped interface between the crystal layers, wherein the polymer layer has a first refractive index, the liquid crystal layer uses dual-frequency liquid crystal, and the dual-frequency liquid crystal is driven by a high-frequency voltage and a low-frequency voltage, A first frequency electric field and a second frequency electric field are generated between the first electrode and the second electrode to respectively apply different frequency voltages to the dual frequency liquid crystal, the first frequency electric field being different from the second frequency electric field.

 Optionally, under the action of the first frequency electric field, the liquid crystal molecules of the dual-frequency liquid crystal are aligned along a direction parallel to the electric field, and the incident linearly polarized light has the first refractive index when passing through the liquid crystal layer. Under the action of the second frequency electric field, the liquid crystal molecules of the dual-frequency liquid crystal are aligned perpendicular to the direction of the electric field, and the incident linearly polarized light passes through the liquid crystal layer and has a larger than the first refractive index. Two refractive index.

 Alternatively, the liquid crystal lens further includes: an alignment layer formed on the first electrode and the second electrode, the alignment layer causing the liquid crystal molecule to be under the action of the second frequency electric field The director direction is parallel to the direction of the linearly polarized light.

 Embodiments of the present invention provide a 2D-3D switchable stereoscopic display device, including a display panel and a liquid crystal lens located above the display panel, wherein the liquid crystal lens includes: a first substrate, on the first substrate Forming a first electrode; a second substrate; a second electrode formed on the second substrate; a polymer layer and a liquid crystal layer disposed between the first electrode and the second electrode, the polymer layer Forming an arcuate interface with the liquid crystal layer, wherein the polymer layer has a first refractive index, the liquid crystal layer is dual-frequency liquid crystal, and the dual-frequency liquid crystal is driven by a high frequency voltage and a low frequency voltage a first frequency electric field and a second frequency electric field are generated between the first electrode and the second electrode to respectively apply different frequency voltages to the dual frequency liquid crystal, the first frequency electric field being different from the second frequency electric field.

 Optionally, under the action of the first frequency electric field, the liquid crystal molecules of the dual-frequency liquid crystal are aligned along a direction parallel to the electric field, and the incident linearly polarized light has the first refractive index when passing through the liquid crystal layer. Under the action of the second frequency electric field, the liquid crystal molecules of the dual-frequency liquid crystal are aligned perpendicular to the direction of the electric field, and the incident linearly polarized light passes through the liquid crystal layer and has a larger than the first refractive index. Two refractive index.

Alternatively, in the above display device, the liquid crystal lens further includes: an alignment layer formed on the first electrode and the second electrode, the alignment layer making an electric field at the second frequency The orientation direction of the liquid crystal molecules is parallel to the direction of the linearly polarized light emitted by the display panel. Optionally, the display device further includes: a driving unit, configured to drive the first electrode and the second electrode to generate the first frequency electric field and the second frequency electric field.

 Alternatively, in the above display device, the driving unit is specifically configured to:

 Generating the first frequency electric field by applying a first frequency voltage between the first electrode and the second electrode, and by applying a second frequency between the first electrode and the second electrode And generating, by the voltage, the second frequency electric field, wherein the first frequency is smaller than a separation frequency of the dual frequency liquid crystal, and the second frequency is greater than a separation frequency of the dual frequency liquid crystal.

 Alternatively, in the above display device, the polarization direction of the linearly polarized light generated by the display panel is perpendicular to the director direction of the liquid crystal molecules under the action of the first frequency electric field, and is parallel to the second frequency The direction of the liquid crystal molecules in the director direction under the action of an electric field. DRAWINGS

 In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below. It is obvious that the drawings in the following description relate only to some embodiments of the present invention, and are not intended to limit the present invention. .

 1 is a schematic diagram of a prior art polarization state switching arc liquid crystal lens method;

 2 is a schematic diagram of a 2D-3D switchable stereoscopic display device according to an embodiment of the present invention;

 Figure 3 is a graph showing the variation of the dual-frequency liquid crystal material with frequency f;

 4 is a schematic view of a liquid crystal lens according to an embodiment of the present invention when driven at a low frequency;

 5 is a schematic view of a liquid crystal lens according to an embodiment of the present invention when driven at a high frequency;

 Fig. 6 is a schematic view showing the direction of the director direction of the liquid crystal molecules of the dual-frequency liquid crystal under the action of a high-frequency electric field. detailed description

 The technical solutions of the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings of the embodiments of the present invention. It is apparent that the described embodiments are part of the embodiments of the invention, rather than all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the described embodiments of the present invention without departing from the scope of the invention are within the scope of the invention.

 Embodiments of the present invention provide a liquid crystal lens in which a dual frequency liquid crystal is used.

Below, a brief description of the dual-frequency liquid crystal material will be given. As shown in FIG. 3, the dielectric anisotropy constant of the dual-frequency liquid crystal material changes as the driving voltage frequency f changes. When a low frequency driving voltage is applied, the dual frequency liquid crystal material becomes a positive liquid crystal of 0>0; when a high frequency driving voltage is applied, the dual frequency liquid crystal material becomes a negative liquid crystal of ^<0. The intersection frequency of the curve with the horizontal axis is called the separation frequency or the transition frequency f. The frequency of the high frequency driving voltage is greater than the separation frequency, and the frequency of the low frequency driving voltage is less than the separation frequency.

 Referring to FIGS. 4 and 5, the liquid crystal lens 8 according to an embodiment of the present invention may include:

 a first substrate 1 , the first substrate 1 is formed with a first electrode 2;

 a second substrate 5, a second electrode 4 is formed on the second substrate 5;

 A polymer interface 3 and a liquid crystal layer 6 disposed between the first electrode 2 and the second electrode 4 form an arcuate interface between the polymer layer 3 and the liquid crystal layer 6. Specifically, the polymer layer 3 forms an IHJ lens, and the liquid crystal layer 6 forms a convex lens, and the IHJ surface of the IHJ lens and the convex surface of the convex lens are combined.

 The polymer layer 3 has a first refractive index, the liquid crystal molecules in the liquid crystal layer 6 are dual-frequency liquid crystals, and the dual-frequency liquid crystals are preferably nematic liquid crystals. A first frequency electric field and a second frequency electric field can be generated between the first electrode 2 and the second electrode 4, and the liquid crystal molecular director is arranged in a direction parallel to the electric field under the action of the first frequency electric field. The linearly polarized light passes through the liquid crystal layer 6 to have the first refractive index; under the action of the second frequency electric field, the liquid crystal molecular directors are arranged in a direction perpendicular to the electric field, and the linearly polarized light passes through the liquid crystal layer 2 The second refractive index is greater than the first refractive index.

 Alternatively, in order to achieve a better display effect, the liquid crystal lens according to an embodiment of the present invention may further include: an alignment layer formed on the first electrode and the second electrode, the alignment layer making The direction of the director direction of the liquid crystal molecules is parallel to the direction of the incident linearly polarized light under the action of the second frequency electric field.

 The liquid crystal lens according to the embodiment of the present invention uses a dual-frequency liquid crystal, which can be driven by a high-frequency voltage and a low-frequency voltage, respectively, so that the liquid crystal lens can realize fast switching of 2D-3D when used for stereoscopic display.

The embodiment of the present invention further provides a 2D-3D switchable stereoscopic display device, which includes a display panel and a liquid crystal lens located above the display panel, wherein the liquid crystal lens is the above-mentioned liquid crystal with dual frequency liquid crystal lens. Covering the above liquid crystal lens on a certain type of display device enables 2D-3D free switching of the display device, and can significantly improve 2D switching to 3D Hysteresis effect.

 One example of the display panel is a liquid crystal display panel in which a TFT array substrate and an opposite substrate are opposed to each other to form a liquid crystal cell in which a liquid crystal material is filled. The opposite substrate is, for example, a color filter substrate. The pixel electrode of each pixel unit of the TFT array substrate is used to apply an electric field to control the degree of rotation of the liquid crystal material to perform a display operation. In some illustrative examples, the liquid crystal display further includes a backlight that provides backlighting for the array substrate.

 Another example of the display panel is an organic electroluminescence display panel (OLED display panel) in which a pixel electrode of each pixel unit of the TFT array substrate serves as an anode or a cathode for driving the organic light-emitting material to emit light for a display operation.

 Further, the display panel may be a plasma display panel, an electronic ink display panel, or the like. As shown in FIG. 2, a schematic diagram of a 2D-3D switchable stereoscopic display device according to an embodiment of the present invention includes a display panel 7 and a liquid crystal lens 8 located above the display panel 7. The symbol ® indicates that the direction of the linearly polarized light emitted from the display panel is perpendicular to the plane of the paper, and the direction of the linearly polarized light emitted from the display panel may be perpendicular to the paper surface or perpendicular to the paper surface, that is, It can be aligned with the director direction of the liquid crystal molecules under the action of the high-frequency electric field.

 In a specific implementation, the first frequency electric field and the first electrode may be generated by driving the first electrode 2 and the second electrode 4 by the driving unit by providing a driving unit in the stereoscopic display device. Two frequency electric field.

 The working principle of the 2D-3D switchable stereoscopic display device is as follows:

 When a 2D display is required, a low frequency voltage is applied between the first electrode 2 and the second electrode 4 by the driving unit, and the low frequency voltage generates a low frequency in the polymer layer 3 and the liquid crystal layer 6. The electric field, the frequency of the low-frequency electric field is lower than the separation frequency of the dual-frequency liquid crystal. At this time, Δ£>0, the liquid crystal molecular director (ie, the optical axis direction) is arranged parallel to the electric field direction, and the linearly polarized light is refracted by the liquid crystal layer 6. The ratio is η丄(η.), and the refractive index η of the polymer layer 3. Similarly, the linearly polarized light is not refracted at the interface between the polymer layer 3 and the liquid crystal layer 6, thereby realizing 2D display. The frequency of the low frequency electric field may be 0 to 1000 Hz, preferably 50 to 200 Hz.

When a 3D display is required, a high frequency voltage is applied between the first electrode 2 and the second electrode 4 by the driving unit, and the high frequency voltage is generated in the polymer layer 3 and the liquid crystal layer 6. a high-frequency electric field, the frequency of the high-frequency electric field is greater than the separation frequency of the dual-frequency liquid crystal. At this time, Δ£<0, the liquid crystal molecular director (ie, the optical axis direction) is arranged along the direction perpendicular to the electric field under the action of the electric field. Line The refractive index of the polarized light passing through the liquid crystal layer 6 is n//( n _e ), which is larger than the refractive index η of the polymer layer 3. The linearly polarized light is refracted at the interface between the polymer layer 3 and the liquid crystal layer 6, thereby realizing 3D display. The frequency of the high frequency electric field may be 10k ~ 1000kHz, preferably 50k ~ 200kHz.

 In the above 2D-3D switchable stereoscopic display device, in order to achieve a better display effect, the polarization direction of the linearly polarized light generated by the display panel is perpendicular to the director direction of the liquid crystal molecules under the action of the first frequency electric field. And parallel to the director direction of the liquid crystal molecules under the action of the second frequency electric field. The first frequency electric field is a low frequency electric field, and the second frequency electric field is a high frequency electric field.

Alternatively, in the above 2D-3D switchable stereoscopic display device, the polarization direction of the linearly polarized light generated by the display panel and the direction of the liquid crystal molecules in the direction of the second frequency (high frequency) electric field In addition to 0°, the included angle may be other angles less than 90 degrees, at which point the refractive index of the light passing through the liquid crystal will be less than n _e , at n. Between n and n _e , a linear polarizing plate is added on the first substrate 1. The transmission axis of the linear polarizing plate is the same as the parallel alignment direction of the liquid crystal molecules to reduce 3D crosstalk and optimize 3D display, wherein liquid crystal molecules The parallel orientation direction is parallel to the director direction of the liquid crystal molecules under the action of the high frequency electric field.

 In addition, when a high-frequency electric field is applied to the dual-frequency liquid crystal, the directors of the liquid crystal molecules are arranged perpendicular to the direction of the electric field, but may be in different directions perpendicular to the electric field, as shown in Fig. 6. Therefore, in order to achieve a better display effect, the liquid crystal lens according to an embodiment of the present invention may further include: an alignment layer (not shown) formed on the first electrode 2 and the second electrode 4, The alignment layer is oriented such that the direction of the director of the liquid crystal molecules is the same under the action of the high-frequency electric field and coincides with the polarization direction of the linearly polarized light emitted from the display panel.

 In summary, the embodiment of the present invention does not require a TN cell switching device. On the basis of the active switching curved liquid crystal lens method, the dual-frequency liquid crystal material and the driving technology can significantly improve the hysteresis effect when 2D is switched to 3D. The 2D-3D can be quickly switched to improve the display effect of the stereoscopic display device.

 It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to be limiting, and those skilled in the art should understand that the technical solutions of the present invention may be modified or equivalently substituted without departing from the technical solutions of the present invention. The spirit of the scope should be covered by the scope of the claims of the present invention.

Claims

Claim A liquid crystal lens comprising:  a first substrate, a first electrode is formed on the first substrate;  a second substrate, a second electrode is formed on the second substrate;  a polymer layer and a liquid crystal layer disposed between the first electrode and the second electrode, and a curved interface is formed between the polymer layer and the liquid crystal layer,  Wherein the polymer layer has a first refractive index, the liquid crystal layer uses a dual-frequency liquid crystal, and the dual-frequency liquid crystal is driven by a high frequency voltage and a low frequency voltage, the first electrode and the second electrode A first frequency electric field and a second frequency electric field are generated to apply different frequency voltages to the dual frequency liquid crystal, the first frequency electric field being different from the second frequency electric field.  2. The liquid crystal lens according to claim 1, wherein a liquid crystal molecular director of the dual-frequency liquid crystal is aligned parallel to an electric field direction by the first frequency electric field, and incident linearly polarized light passes through the liquid crystal The layer has the first refractive index, and under the action of the second frequency electric field, the liquid crystal molecules of the dual-frequency liquid crystal are aligned perpendicular to the direction of the electric field, and the incident linearly polarized light passes through the liquid crystal layer. a second refractive index greater than the first refractive index.  3. The liquid crystal lens of claim 1, further comprising:  An alignment layer formed on the first electrode and the second electrode, the alignment layer being such that a direction of a director of the liquid crystal molecule is parallel to a direction of the linearly polarized light under the action of the second frequency electric field .  4. The liquid crystal lens according to claim 1, wherein the dual frequency liquid crystal is a nematic liquid crystal. The liquid crystal lens according to claim 1, wherein the frequency of the first frequency electric field is 0 to 1000 Hz.  6. The liquid crystal lens according to claim 1, wherein the frequency of the first frequency electric field is 50 to 200 Hz.  7. The liquid crystal lens according to claim 1, wherein the frequency of the second frequency electric field is 10 k to 1000 kHz.  The liquid crystal lens according to claim 1, wherein the frequency of the two-frequency electric field is 50 k to 200 kHz. 9. A 2D-3D switchable stereoscopic display device, comprising: Display panel  a liquid crystal lens located above the display panel, the liquid crystal lens comprising:  a first substrate, a first electrode is formed on the first substrate;  a second substrate, a second electrode is formed on the second substrate;  a polymer layer and a liquid crystal layer disposed between the first electrode and the second electrode, and an arc-shaped interface is formed between the polymer layer and the liquid crystal layer;  Wherein the polymer layer has a first refractive index, the liquid crystal layer uses a dual-frequency liquid crystal, and the dual-frequency liquid crystal is driven by a high frequency voltage and a low frequency voltage, the first electrode and the second electrode A first frequency electric field and a second frequency electric field can be generated to apply different frequency voltages to the dual frequency liquid crystals, respectively.  10. The 2D-3D switchable stereoscopic display device according to claim 9, wherein the liquid crystal molecular director is arranged parallel to the direction of the electric field under the action of the first frequency electric field, and the linearly polarized light emitted by the display panel The liquid crystal layer has the first refractive index, and under the action of the second frequency electric field, the liquid crystal molecules are aligned perpendicular to the electric field direction, and the linearly polarized light passes through the liquid crystal layer has a larger than the first A second refractive index of a refractive index.  11. The display device as claimed in claim 9, wherein the liquid crystal lens further comprises:  An alignment layer formed on the first electrode and the second electrode, the alignment layer causing linear polarization of the liquid crystal molecule in a director direction and the display panel under the action of the second frequency electric field The direction of the light is parallel.  12. The display device of claim 9, further comprising:  And a driving unit, configured to drive the first electrode and the second electrode to generate the first frequency electric field and the second frequency electric field.  13. The display device according to claim 12, the driving unit  The first frequency electric field is generated by applying a first frequency voltage between the first electrode and the second electrode, and the driving unit is applied between the first electrode and the second electrode The second frequency voltage is generated to generate the second frequency electric field, wherein the first frequency is smaller than a separation frequency of the dual frequency liquid crystal, and the second frequency is greater than a separation frequency of the dual frequency liquid crystal.  14. The display device of claim 9, wherein The polarization direction of the linearly polarized light generated by the display panel is perpendicular to a director direction of the liquid crystal molecules under the action of the first frequency electric field, and parallel to the liquid crystal layer under the action of the second frequency electric field Sub-director direction.  The display device according to claim 9, wherein an angle between a polarization direction of the linearly polarized light generated by the display panel and a director direction of the liquid crystal molecules under the second frequency electric field is less than 90°.