KR101677997B1 - Stereoscopic 3d display device and method of driving the same - Google Patents

Abstract

The stereoscopic image display apparatus and the driving method thereof according to the present invention minimize the deterioration of 3D performance by minimizing liquid crystal distortion of a liquid crystal lens, which occurs when a Fresnel lens is implemented by a liquid crystal lens to reduce a cell gap. A first substrate and a second substrate having a plurality of lens regions having a plurality of partial regions defined and spaced apart from each other; A plurality of first electrodes formed on an inner surface of the first substrate and a plurality of second electrodes formed on an inner surface of the second substrate, for each of the lens regions; And a liquid crystal layer formed between the first substrate and the second substrate, the liquid crystal lens being driven according to a voltage applied thereto and having a lens function; And a display panel disposed below the liquid crystal lens and outputting two-dimensional image information. A voltage having a different polarity and an absolute value based on a common voltage is applied to the first electrode and the second electrode facing each other, And the liquid crystal layer is controlled by a refractive index distribution having a refractive index distribution.

Description

TECHNICAL FIELD [0001] The present invention relates to a stereoscopic image display device,

The present invention relates to a stereoscopic image display apparatus and a driving method thereof, and more particularly, to a stereoscopic image display apparatus and a driving method thereof, in which a Fresnel lens is implemented by a liquid crystal lens to reduce a cell gap .

A simple definition of 3D display is "the total system that artificially reproduces the 3D screen".

Here, the system includes a software technique that can be viewed in 3D and a hardware that actually realizes the content created by the software technique in 3D. The reason for incorporating the software area is that the 3D display hardware requires separately configured contents in a separate software manner for each stereoscopic implementation method.

In addition, the virtual 3D display makes it possible to literally feel the stereoscopic effect in the flat display hardware by using the binocular disparity which is caused when the eye is about 65 mm away from the horizontal direction among the various factors of the human feeling of three-dimensional feeling System. In other words, our eyes see a different image (a little bit of space between the left and the right, respectively) even if we look at the same things because of binocular parallax. When these two images are transmitted to the brain through the retina, By fusing them exactly, we can feel the stereoscopic effect. It is the virtual 3D display that uses it to create a virtual stereoscopic effect through a design that simultaneously displays two left and right images on a 2D display device and sends them to each eye.

In order to display images of two channels on one screen in such a virtual 3D display hardware device, in most cases, one channel is changed one line at a time horizontally or vertically in one screen. At the same time, when images of two channels are output from one display device, in the case of a non-eyeglass system due to the hardware structure, the right image enters the right eye as it is, and the left image enters only the left eye. In addition, in the case of wearing the glasses, the right image is visually obscured by the special glasses suitable for each method, and the left image is obscured by the right eye so that the right eye can not be seen.

As mentioned above, the binocular parallax due to the interval between the two eyes is the most important factor for the person to feel the three-dimensional feeling and the depth feeling, but there is also a deep relationship with the psychological and memory factors. Accordingly, Dimensional image information, a volumetric type, a holographic type, and a stereoscopic type based on whether the three-dimensional image information can be provided.

The volume expression method is a method for making the depth direction perceive by the psychological factors and the suction effect, and is a three-dimensional computer graphic which displays the perspective method, overlapping, shading, contrast, and movement by calculation, So-called IMAX films, which give rise to an optical illusion that it is sucked into the space by providing a large screen.

The three-dimensional representation known as the most complete stereoscopic imaging technique can be represented by laser light reproduction holography or white light reproduction holography.

As described above, when an association image of a plane including parallax information is displayed on the left and right sides of a human being present at a distance of about 65 mm as described above, the brain expresses three-dimensional images using the physiological factors of both eyes. And the ability to generate spatial information before and after the display surface in the process of fusing them to sense a stereoscopic effect, that is, stereography. Such a three-dimensional expression system is largely classified into a system in which glasses are worn and a system in which glasses are not worn.

Representative examples of a method of not wearing glasses include a lenticular method and a parallax barrier method in which a lenticular lens plate vertically arranging a cylindrical lens is disposed in front of the display panel.

1 is a cross-sectional view showing a typical lenticular lens type stereoscopic image display apparatus.

As shown in the figure, a typical lenticular lens type stereoscopic image display apparatus includes a liquid crystal panel 10 in which liquid crystal 6 is filled between upper and lower substrates 5 and 15, a liquid crystal panel 10 between the liquid crystal panel 10 and the liquid crystal panel 10, And a lenticular plate 30 positioned on the front surface of the liquid crystal panel 10 for realizing a stereoscopic image.

At this time, first and second polarizers 1 and 11 are attached to the upper surface of the upper substrate 5 and the lower surface of the lower substrate 15, respectively.

The lenticular plate 30 is formed by forming a material layer having a convex lens shape on its upper surface on a flat substrate.

Here, the image image transmitted through the liquid crystal panel 10 passes through the lenticular plate 30 and another group of images comes into each eye of the final observer, so that a three-dimensional stereoscopic image can be felt.

The liquid crystal panel 10 and the lenticular plate 30 are supported by an instrument or the like so that the first polarizer 11 on the liquid crystal panel 10 and the lenticular plate 30 on the liquid crystal panel 10, Are spaced apart from each other by a predetermined distance.

In this case, the liquid crystal panel 10 or the lenticular plate 30 may sag or bend into a space between the first polarizer 11 and the lenticular plate 30 on the liquid crystal panel 10. If such a bending phenomenon occurs, there is a problem that the light path that is finally transmitted through the backlight unit 20, the liquid crystal panel 10, and the lenticular plate 30 is generated, thereby lowering the image quality.

In recent years, a liquid crystal lens, that is, a liquid crystal lens electrically driven, has been proposed in which the liquid crystal layer serves as a lens using the characteristics of liquid crystal molecules.

That is, a general lens controls the path of the incident light according to the position by using the refractive index difference between the material constituting the lens and air. However, it is possible to configure the liquid crystal layer to be driven by different vertical electric fields for each position by applying different voltages to the liquid crystal layers at different positions without forming the lens of such a physical shape. Then, the incident light incident on the liquid crystal layer experiences a different phase change for each position, and as a result, the liquid crystal layer can control the path of the incident light like an actual lens. An array structure including a liquid crystal and electrodes for driving the liquid crystal is referred to as a liquid crystal electric field lens when the vertical electric field is applied and the transmission of light by the driving of the liquid crystal is obtained as it is transmitted through the lens.

At this time, in order to appropriately change the phase of the liquid crystal lens by using the vertical electric field as described above, the thickness of the liquid crystal layer is required to be several times to several tens times as large as the thickness of the liquid crystal layer of a general liquid crystal display device. That is, the focal length of the liquid crystal lens is inversely proportional to the refractive index anisotropy of the liquid crystal and the thickness (cell gap) of the lens. Therefore, the cell gap of the liquid crystal lens should be 20 占 퐉 to 100 占 퐉 according to the necessary focal distance.

However, in the process of manufacturing a liquid crystal display device, the liquid crystal panel has a cell gap of about 3 to 10 mu m, and equipment which is advantageous for manufacturing a liquid crystal panel having a cell gap within this range is used. In order to manufacture a liquid crystal lens having a cell gap of 10 m or more in such a situation, the manufacturing apparatus should be replaced with a structure favorable for manufacturing a liquid crystal panel having a large cell gap, It is necessary to develop new materials to enhance the durability so as not to cause crushing by crushing.

In this case, the material cost due to the increase in the thickness of the liquid crystal layer increases, resulting in an increase in the manufacturing cost of the product, and furthermore, the equipment itself must be replaced.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a stereoscopic image display device and a method of driving the liquid crystal display device in which a thickness of a liquid crystal layer constituting a liquid crystal lens, And the like.

It is another object of the present invention to provide a stereoscopic image display device and a method of driving the same that minimize the deterioration of 3D performance due to an error caused by liquid crystal distortion by minimizing the liquid crystal distortion of the liquid crystal lens.

Other objects and features of the present invention will be described in the following description of the invention and claims.

According to another aspect of the present invention, there is provided a method of driving a stereoscopic image display device including a liquid crystal lens driven by a voltage applied thereto and having a lens function, And a panel.
The liquid crystal lens may include a first substrate and a second substrate which are defined by a plurality of lens regions having a plurality of partial regions and are spaced apart from each other, a liquid crystal layer provided between the first substrate and the second substrate, A plurality of upper first electrodes and a plurality of lower first electrodes arranged to be spaced apart from each other on the inner surface of the first substrate, and a plurality of lower first electrodes arranged on the inner surface of the second substrate, And may include an upper second electrode and a plurality of lower second electrodes.
In the stereoscopic image display apparatus of the present invention, the upper and lower first electrodes and the upper and lower second electrodes are located at the boundaries between the respective partial regions to constitute a shielding electrode having a larger width than the other electrodes A voltage having a different polarity and the same absolute value as the common voltage is applied to the upper and lower first electrodes and the upper and lower second electrodes which are opposed to each other.
Further, in the method of driving a liquid crystal lens of the present invention, the electrode positioned at the boundary between the upper and lower first electrodes and the upper and lower second electrodes is composed of a shielding electrode having a greater width than the other electrodes And a voltage having a different polarity and having an absolute value different from each other is applied to the upper and lower first electrodes and the upper and lower second electrodes facing each other based on a common voltage and the voltage is not applied to the shield electrode, .

The display panel may further include a light source positioned below the display panel to transmit light to the display panel.

The display panel is characterized in that first and second image pixels respectively displaying the first and second images are sequentially and repeatedly arranged.

The display panel is one of a liquid crystal display, an organic light emitting display, an electroluminescent display, a plasma display, and an electroluminescent display.

And a plurality of first electrodes are formed on an inner surface of the first substrate with respect to each of the lens regions, with a first insulating layer interposed therebetween.

And a plurality of second electrodes are formed on an inner surface of the second substrate with respect to each of the lens regions, with a second insulating layer interposed therebetween.

Wherein a plurality of upper first electrodes of the first substrate are disposed opposite a plurality of lower second electrodes of the second substrate and a plurality of lower first electrodes of the first substrate are disposed on a plurality of upper And the second electrodes are disposed opposite to each other.

And a voltage source formed on the first substrate or the second substrate to apply different voltages to the plurality of first electrodes and the plurality of second electrodes, respectively.

And the electrodes located at the boundary between the partial regions of the plurality of first electrodes and the second electrodes constitute a shielding electrode to which no voltage is applied or 0V is inputted.

And the one lens region is divided into at least three partial regions.

The plurality of first electrodes and the plurality of second electrodes are formed in a symmetrical shape with respect to the lens region and the edge portion of the lens region.

A first voltage Vmin corresponding to a threshold voltage is applied to the first and second opposing electrodes located at the center of the lens region. In this case, a first voltage Vmin having a different polarity from the common voltage, Vmin) is applied.

In this case, the n-th voltage Vmax having a different polarity and the same absolute value as the common voltage is applied to the opposing first and second electrodes located at the edge portions of the lens regions. Respectively.

Wherein a voltage applied to the opposing first and second electrodes located between the center and the edge of the lens region is between a threshold voltage Vmin of the lens region and the nth voltage Vmax, A voltage having a value which is different from the common voltage and has the same absolute value is applied to the first and second electrodes on the upper and lower sides, respectively .

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As described above, in the stereoscopic image display device and the driving method thereof according to the present invention, the Fresnel lens is implemented by appropriately adjusting the voltage to a plurality of electrodes provided for forming a liquid crystal lens, Cell gap level. As a result, the manufacturing cost can be reduced by reducing the material cost.

The stereoscopic image display apparatus and the driving method thereof according to the present invention minimize the liquid crystal distortion of the liquid crystal lens and reduce the transmission error caused by the liquid crystal distortion to about 60 to 70% of the conventional level.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a stereoscopic image display apparatus of a general lenticular lens system. Fig.
2 is a cross-sectional view schematically showing a structure of a liquid crystal lens according to a first embodiment of the present invention.
3 is a table showing, for example, a 1/2 unit electrode width and an applied voltage of a Fresnel lens.
4 is a graph showing a comparison between the cell gap of the liquid crystal lens of the comparative example and the Fresnel lens.
Fig. 5 is a diagram showing an ideal Fresnel lens and a liquid crystal lens according to a first embodiment of the present invention in comparison with phase changes of incident light when light passes through it. Fig.
6 is a view showing a phase change of incident light when light passes through the liquid crystal lens according to the first embodiment of the present invention when 0 V is applied to an ideal Fresnel lens.
7 is a cross-sectional view schematically showing the structure of a liquid crystal lens according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view schematically showing the structure of a stereoscopic image display apparatus having a liquid crystal lens according to a second embodiment of the present invention shown in FIG. 7; FIG.
9A and 9B are views showing a method of applying a voltage to a liquid crystal lens in a stereoscopic image display apparatus according to the first embodiment and the second embodiment of the present invention, respectively.
10 is a graph comparing transmittance errors (error) according to 1/2 unit lens pitch in the liquid crystal lenses according to the first and second embodiments of the present invention.

Hereinafter, preferred embodiments of a stereoscopic image display apparatus and a driving method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view schematically showing the structure of a liquid crystal lens according to a first embodiment of the present invention.

As shown in the figure, the liquid crystal lens 110 according to the first embodiment of the present invention has a function of emitting a two-dimensional image signal as a three-dimensional image signal like a profile of a lens surface, And a liquid crystal layer 106 formed between the first substrate 105 and the second substrate 115. The first substrate 105 and the second substrate 115 are spaced apart from each other with a lens region defined therebetween.

At this time, a common electrode 107 made of a transparent conductive material, that is, a first electrode is formed on the entire surface of the first substrate 105 on the first substrate 105 as an upper substrate.

A plurality of second electrodes 117a and 117b are formed on the inner surface of the second substrate 115 which is a lower substrate facing the first substrate 105 with respect to the respective lens regions, 119 are interposed therebetween. However, the present invention is not limited thereto, and the plurality of second electrodes 117a and 117b may be separated from each other on a single layer. At this time, the plurality of second electrodes 117a and 117b may be made of a transparent conductive material.

V2 ',..., Vmax') are applied to the second electrodes 117a and 117b, respectively, on the second substrate 115, May be formed.

A first alignment layer 108 and a second alignment layer 118 are formed on inner surfaces of the first substrate 105 and the second substrate 115 having such a structure. A liquid crystal layer 106 is formed between the first substrate 105 and the second substrate 115 on which the two orientation films 118 are formed. At this time, between the plurality of second electrodes 117b formed on the insulating layer 119 and the second alignment layer 118, the overcoat layer (not shown) Not shown) can be further formed.

Meanwhile, in the liquid crystal lens 110 according to the first embodiment of the present invention configured as described above, the electrodes located at the boundaries of the respective partial regions of the plurality of second electrodes 117a and 117b constitute the shielding electrode In this case, the shielding electrode may be formed with a larger width than the other electrodes. Here, in order to reduce the thickness of the lens, one lens region may be divided into at least three partial regions, or may be divided into five or seven partial regions.

The plurality of lower second electrodes 117a and the plurality of upper second electrodes 117b may be spaced apart from each other to have the same size. They may be formed at different intervals.

At this time, a first voltage Vmin 'corresponding to a threshold voltage is applied to the second electrodes 117a and 117b located at the center of the lens region, and the second electrodes 117a and 117b positioned at the edge portions of the lens regions The highest n-th voltage Vmax 'is applied. In this case, the voltage applied to the plurality of second electrodes 117a and 117b located between the center of the lens region and the edge portion is between the threshold voltage Vmin 'of the lens region and the nth voltage Vmax' A voltage of a value which gradually increases as the distance from the center of the lens region is applied. If a ground voltage is applied to the common electrode 107 in a state where a voltage is applied to the plurality of second electrodes 117a and 117b as described above, A vertical electric field is formed between the common electrodes 107.

When a voltage is applied in this manner, the voltage difference applied between the plurality of second electrodes 117a and 117b adjacent to each other becomes 1V or less, and a horizontal electric field formed between the plurality of second electrodes 117a and 117b It should not occur to a large extent.

The second electrodes 117a and 117b and the common electrodes 107a and 117b are electrically connected to the second electrodes 117a and 117b by a voltage gradually decreasing from the edge portion to the center of the lens region. ), And the entirety thereof has the same phase change as a convex lens having a convex semicircular or parabolic shape.

At this time, in order to implement the Fresnel lens, in the partial area located at the most central part among the above-mentioned three, five or seven odd partial areas (hereinafter referred to as the central partial area) A gradually increasing voltage is applied to the second electrodes 117a and 117b with respect to the second electrodes 117a and 117b located on both sides of the second electrodes 117a and 117b positioned at the center of the central part partial area with respect to the second electrodes 117a and 117b . In the partial region located on the left side of the central partial region among the partial regions except for the central partial region, the second electrodes 117a and 117b from the leftmost second electrodes 117a and 117b to the rightmost second electrode 117a and 117b A large voltage is applied at a small voltage in the order from the leftmost second electrode 117a, 117b to the rightmost second electrode 117a, 117b in the partial region located on the right side of the central portion partial region can do.

As a result, not all of the convex lenses have a phase shift such as a convex lens having a convex semi-circular or parabolic shape but a plurality of discontinuities, and the role of the Fresnel lens is the same as that of a Fresnel lens. Therefore, the size of the cell gap, which is the thickness of the liquid crystal layer, can be remarkably reduced by the above-described electrode configuration and driving method.

In particular, when 0 V is applied to the shield electrode located at the boundary between the partial regions, a liquid crystal lens having a plurality of discontinuous surfaces and having the same phase change as an ideal Fresnel lens can be realized.

FIG. 3 is a table showing, for example, a half unit electrode width and an applied voltage of the Fresnel lens, and FIG. 4 is a graph showing a comparison between the cell gap of the liquid crystal lens and the Fresnel lens of the comparative example.

Referring to FIG. 3, a voltage is applied to the portion "A" of FIG. 4 under the same condition as that of the conventional liquid crystal lens. That is, the voltage is continuously lowered until the electrodes 1 to 8, In order to realize the Fresnel lens, the 6.23V voltage similar to the voltage (5.98V) of the first electrode is applied to align the liquid crystal molecules completely vertically.

Referring to FIG. 4, a comparative example in which the electrodes are arranged in the same manner as in the first embodiment of the present invention, a threshold voltage is applied to an electrode located at the center of one lens region, When a voltage having a gradually increasing value is applied to the electrodes located on the left and right sides thereof, a convex semi-circular or parabolic lens having a phase change without a discontinuity is formed.

In other words, the phase change waveform of the light for the liquid crystal lens of the comparative example does not have the discontinuous surface unlike the liquid crystal lens according to the first embodiment of the present invention, but when the same first focal distance is used, It is found that a cell gap of 20 mu m, which is twice as large as that of the liquid crystal lens, is formed.

At this time, to implement the Fresnel lens, 6.23V is applied to the 10th electrode and 2.21V is applied to the 8th electrode as shown in FIG. 3, and a horizontal electric field is formed between 8th and 6th due to the difference, The liquid crystal array is twisted by this electric field, and the lens shape is collapsed as shown in Fig. 5 below.

FIG. 5 is a diagram showing an ideal Fresnel lens and a liquid crystal lens according to the first embodiment of the present invention, in comparison with the phase change of incident light when light passes through. FIG. That is, the result of simulating the shape of the Fresnel lens according to the first embodiment of the present invention when 0 V is not applied to the shield electrode.

5, for example, simulates a phase change of incident light when light passes through one lens region of three partial regions. The solid line represents simulation results, and the dotted line represents an ideal Fresnel lens shape Respectively.

As shown in the drawing, when a voltage is applied to one lens region FA including a plurality of partial regions A1, A2, and A3 in the liquid crystal lens according to the first embodiment of the present invention, It can be seen that the phase shift of light passing through the liquid crystal lens by the partial regions A1, A2, and A3 of the Fresnel lens is formed in the form of a Fresnel lens having a plurality of discontinuous surfaces. In FIG. 5, when a liquid crystal lens having a first focal length is implemented, a cell gap of about 10 탆 is formed.

However, in the case of the partial regions A1 and A3 positioned on the left and right sides of the central partial region A2, the phase change waveforms of the partial regions A2 and A3 are substantially the same as those of the ideal Fresnel lens. It can be seen that there is a difference from the waveform of the ideal Fresnel lens.

In particular, at the boundary between the partial regions A1, A2, and A3 forming the discontinuity, a vertical waveform must be formed to minimize the error due to the discontinuity. However, since the vertical waveform does not appear and has a predetermined slope, It differs from the ideal Fresnel lens waveform. At this time, it can be understood that the maximum value of the waveforms in these partial regions A1, A2, and A3 is formed in the vicinity of the liquid crystal layer of about 8 mu m.

Thus, the difference in the maximum value of the waveforms in the partial regions A1, A2, and A3 means that the lens has a difference in curvature. That is, since the convex lenses having different radii of curvature are transmitted through the convex lenses, there is a possibility that many errors occur as lenses. In other words, in the liquid crystal lens according to the first embodiment, the phase shift of the light passing through the partial area A2 at the center and the phase of light passing through the partial areas A1 and A3 located at the left and right of the central part area It means that there is a difference in the change.

In order to solve this problem, in the first embodiment of the present invention, the ninth electrode is made to be a shielding electrode. That is, 0V is applied to the No. 9 electrode to shield the high voltage of the adjacent electrode. Since the concept after the "A" portion is the same as that of a general liquid crystal lens other than the Fresnel lens, if a gradually lower voltage is applied to the electrodes 10 to 24 as shown in FIG. 3, The shape can be obtained.

6 is a diagram showing a phase change of incident light when light passes through the liquid crystal lens according to the first embodiment of the present invention when 0 V is applied to an ideal Fresnel lens.

In the liquid crystal lens according to the first embodiment of the present invention, as shown in the figure, when a shielding electrode is not formed at the boundary between the partial regions A1, A2, and A3, It can be seen that the light passing through the lens region FA having the ideal Fresnel lens has a waveform similar to the phase change of the light passing through the ideal Fresnel lens.

That is, a waveform is formed similar to a nearly ideal Fresnel lens waveform at the boundaries of the partial regions A1, A2, and A3 with respect to the phase change waveform (see FIG. 5) when 0 V is not applied to the shield electrode . It can also be seen that the boundary between the partial regions A1, A2, and A3 is formed to have a straight line shape more similar to the ideal Fresnel lens waveform.

In this case, FIG. 6 illustrates a case where 0 V or no voltage is applied to the shield electrode. However, a predetermined voltage may be applied to the shield electrode in addition to the case where 0 V or no voltage is applied to the shield electrode. That is, when a common electrode is formed on the entire surface of the upper substrate, a voltage equal to the voltage applied to the common electrode may be applied. The reason why the voltage is applied to the common electrode of the upper substrate is to prevent deterioration of the liquid crystal. Applying a voltage of a predetermined magnitude to the common electrode and alternately applying a larger voltage and a smaller voltage to the plurality of second electrodes based on the voltage value, And a smaller voltage is applied to prevent deterioration due to rotation of the liquid crystal in a specific direction. In this case, the same voltage applied to the common electrode is applied to the shield electrode so that the voltage sensed by the plurality of electrodes is substantially 0V.

However, even in this case, there is a liquid crystal distortion because the voltage difference between the adjacent electrodes is large at the boundary of each partial region. That is, when a Fresnel lens is implemented by a liquid crystal lens for the purpose of lowering the cell gap, since a voltage is applied to the common electrode of the upper substrate with the shielding electrode placed at the part where the lens is divided, , Which serves as an error factor in implementing a liquid crystal lens for implementing 3D.

In the second embodiment of the present invention, a plurality of first electrodes having the same structure as that of the lower substrate are formed on the upper substrate. In the first embodiment of the present invention, The liquid crystal deviations due to the horizontal electric field can be minimized by dividing the liquid crystal molecules into a plurality of first and second electrodes of the substrate, respectively.

7 is a cross-sectional view schematically showing the structure of a liquid crystal lens according to a second embodiment of the present invention.

8 is a cross-sectional view schematically showing the structure of a stereoscopic image display apparatus having a liquid crystal lens according to a second embodiment of the present invention shown in FIG.

As shown in the figure, a stereoscopic image display device having a liquid crystal lens according to a second embodiment of the present invention includes a liquid crystal lens 210 driven by a voltage applied thereto and having a lens function, And a light source 220 positioned below the display panel 240 and transmitting light to the display panel 240. The display panel 240 includes a display panel 240,

In this case, if the display panel 240 directly emits light, the light source 220 may be omitted.

First and second image pixels P1 and P2 for sequentially displaying the first and second images IM1 and IM2 are sequentially and repeatedly arranged on the display panel 240. The display panel 240 includes a display panel 240, Type or projection type liquid crystal display (LCD), an organic light emitting diode (OLED) display, a field emission display (FED), a plasma display panel (PDP), and an electroluminescent display (EL) may be used.

The liquid crystal lens 210 according to the second embodiment of the present invention has a function of emitting a two-dimensional image signal as a three-dimensional image signal like a profile of a lens surface, And selectively outputs a three-dimensional image signal or a two-dimensional image signal according to whether a voltage is applied or not. That is, by using the characteristic that the light is transmitted when the voltage is not applied, the switching function such as the two-dimensional display when the voltage is not applied and the three-dimensional display when the voltage is applied can be used.

In one liquid crystal lens 210, a lens region L having a portion having such an optical path difference is periodically repeated.

8, one lens region L of the liquid crystal lens 210 corresponds to a width of two image pixels P1 and P2 of the display panel 240 located below the liquid crystal lens 210 However, the present invention is not limited to this, and a plurality of image pixels may be formed corresponding to the one lens region L.

Hereinafter, the liquid crystal lens 210 according to the second embodiment of the present invention will be described in detail.

The liquid crystal lens 210 according to the second embodiment of the present invention includes a first substrate 205 and a second substrate 215 in which a plurality of lens regions L are defined and spaced apart from each other, And a liquid crystal layer 206 formed between the second substrate 215 and the second substrate 215.

At this time, a plurality of first electrodes 207a and 207b are spaced apart from each other by a first insulating layer 209 with respect to the respective lens regions L on the inner surface of the first substrate 205, Respectively. However, the present invention is not limited thereto, and the plurality of first electrodes 207a and 207b may be spaced apart from each other on a single layer. At this time, the plurality of first electrodes 207a and 207b have a fine line width and may be made of a transparent conductive material.

A plurality of second electrodes 217a and 217b are formed on the inner surface of the second substrate 215 which is a lower substrate facing the first substrate 205 with respect to the respective lens regions L And is spaced apart with a second insulating layer 219 therebetween. However, the present invention is not limited thereto, and the plurality of second electrodes 217a and 217b may be spaced apart from each other on a single layer. At this time, the plurality of second electrodes 217a and 217b have a fine line width and may be made of a transparent conductive material.

The width of each of the first and second electrodes 207a, 207b, 217a and 217b may be, for example, about 5 占 퐉 to 10 占 퐉 and the distance between the adjacent first and second electrodes 207a, 207b, 217a, The interval may be, for example, about 5 mu m to 10 mu m. At this time, the pitch of one lens region L may be variously variable, for example, from about 90 μm to about 1000 μm. The first and second electrodes 207a, 207b, 217a and 217b according to the width and spacing distance of the lens region L,

Although not shown in the drawing, the first substrate 205 or the second substrate 215 may have different voltages (±) applied to the first electrodes 207a and 207b and the second electrodes 217a and 217b, respectively, Vmin, ± V1, ± V2, ...., ± Vmax) may be formed.

A first alignment layer 208 and a second alignment layer 218 are formed on inner surfaces of the first substrate 205 and the second substrate 215 having such a configuration. A liquid crystal layer 206 is formed between the first substrate 205 and the second substrate 215 on which the two orientation films 218 are formed. At this time, a plurality of first and second electrodes 207a, 207b, 217a, and 217b formed on the first and second insulating layers 209 and 219 and a second An overcoat layer (not shown) in a state where its surface is flat without being affected by the step difference due to the constituent elements of the overcoat layer can be further formed.

In order to make the liquid crystal lens 210 function as a transmission layer in an initial state at the time of no voltage application, the first and second alignment layers 208 and 218 may be formed so that the rubbing direction of the second alignment layer 218 is the second And may be perpendicular to the longitudinal direction of the electrodes 217a and 217b. At this time, the rubbing direction of the first alignment layer 208 may be anti-parallel or anti-parallel to each other.

On the other hand, in the liquid crystal lens 210 according to the second embodiment of the present invention configured as described above, a plurality of first electrodes 207a and 207b and a plurality of second electrodes 217a and 217b The positioned electrode may constitute a shielding electrode, in which case the shielding electrode may be formed with a greater width than the other electrodes. Here, in order to reduce the thickness of the lens, one lens region L may be divided into at least three partial regions, or may be divided into five or seven partial regions.

The plurality of lower first electrodes 207a and the plurality of lower first electrodes 207b may be spaced apart from each other to have the same size. Meanwhile, the plurality of lower second electrodes 217a may be spaced apart from each other, And the plurality of upper second electrodes 217b may be spaced apart from each other so as to have the same size.

7 and 8, a plurality of upper first electrodes 207a of the first substrate 205 are arranged to face a plurality of lower second electrodes 217a of the second substrate 215 And a plurality of lower first electrodes 207b of the first substrate 205 are arranged to oppose a plurality of upper second electrodes 217b of the second substrate 215. However, The present invention is not limited thereto.

The plurality of first electrodes 207a and 207b and the second electrodes 217a and 217b are symmetrically formed in the lens region L with the edge portion of the lens region L as a boundary.

The first and second images IM1 and IM2 emitted from the display panel 240 are transmitted to the first and second viewing zones V1 and V2 by the liquid crystal lens 210, If the distance between the first and second viewing zones V1 and V2 is designed to be a distance between two eyes of a person, the user can easily select the first and second images IM1 and V2 transmitted to the first and second viewing zones V1 and V2, , IM2) are synthesized to recognize the three-dimensional image due to the binocular parallax.

When no voltage is applied to the first and second electrodes 207a and 207b and the second electrodes 217a and 217b, the liquid crystal lens 210 is moved to the first and second images IM1 and IM2 of the display panel 240, , IM2) as a simple transparent layer that displays the light without refraction. Accordingly, the first and second images IM1 and IM2 are transmitted to the user as they are, and the user recognizes the two-dimensional image.

A first voltage Vmin corresponding to a threshold voltage is applied to the opposing first and second electrodes 207a, 207b, 217a, and 217b located at the center of the lens region L. The first voltage Vmin, The first and second electrodes 207a, 207b, 217a, and 217b located at the centers of the first and second electrodes L and L are applied with the first voltage Vmin having a different polarity and an absolute value based on the common voltage. In this case, the first voltage Vmin according to the second embodiment of the present invention is applied to the first and second electrodes 207a, 207b, 217a, and 217b on the upper and lower sides, And has a value corresponding to 1/2 of the first voltage Vmin 'according to the embodiment.

The largest n-th voltage Vmax is applied to the opposing first and second electrodes 207a, 207b, 217a, and 217b located at the edge portions of the lens regions L. In this case, The n-th voltage Vmax having a different polarity and the same absolute value is applied. At this time, the n-th voltage Vmax according to the second embodiment of the present invention is applied to the first and second electrodes 207a, 207b, 217a, and 217b on the upper and lower sides, And has a value corresponding to 1/2 of the n-th voltage Vmax 'according to the embodiment. In this case, a voltage applied to the opposing first and second electrodes 207a, 207b, 217a, and 217b positioned between the center of the lens region L and the edge portion is the voltage applied to the lens region L A voltage of a value which gradually increases as the distance from the center of the lens region L is applied between the threshold voltage Vmin and the n-th voltage Vmax. The polarity is different on the basis of the common voltage, A voltage is applied to the upper and lower first and second electrodes 207a, 207b, 217a, and 217b, respectively.

When the voltage is applied in this manner, the voltage difference applied between the plurality of first electrodes 207a and 207b adjacent to each other or between the plurality of second electrodes 217a and 217b becomes 1 / 2V or less, The horizontal electric field formed between the first electrodes 207a and 207b or between the second electrodes 217a and 217b is minimized.

9A and 9B are views showing a method of applying a voltage to the liquid crystal lens in the stereoscopic image display apparatus according to the first and second embodiments of the present invention, respectively.

9A and 9B, in the first embodiment of the present invention, a common voltage of 0 V is applied to the first electrode of the upper substrate, that is, the common electrode, and the second electrode of the lower substrate has a threshold voltage The voltage is applied so as to gradually increase from the center of the lens region at a non-uniform interval from 1.7 V as the first voltage Vmin 'to the n-th voltage Vmax' as the maximum voltage to 6 V.

In the second embodiment of the present invention, the voltages Vmin ', V1', V2 ',..., Vmax' applied to the second electrodes of the lower substrate in the method of the first embodiment, The voltage (0 V) applied to the first electrode is distributed to the upper and lower substrates, and voltages (± Vmin, ± V1, ± V2, ...., ± Vmax) having different polarities and the same absolute value are applied, Thereby realizing a Fresnel lens. That is, a voltage of Vmin '/ 2, V1' / 2, V2 '/ 2, ...., Vmax' / 2 is applied to the second electrode of the lower substrate in the direction away from the center of the lens region, A voltage of -Vmin '/ 2, -V1' / 2, -V2 '/ 2, ..., -Vmax' / 2 is sequentially applied to the first electrode of the upper substrate in the direction away from the center of the lens region Lens shape.

For example, as the distance from the center of the lens region to the second electrode of the lower substrate increases from <0.85 V with a first voltage (Vmin), which is a threshold voltage, to a voltage (Vmax) The voltage is applied to the first electrode of the upper substrate at a non-uniform interval from <-0.85 V with the first voltage (-Vmin) as a threshold voltage to <-3 V with the n-th voltage (-Vmax) The voltage is applied so that the distance from the center of the region increases.

As a result of simulating the lens according to the second embodiment of the present invention, the voltage applied to the method according to the first embodiment is <Vmin '/ 2, <V1' / 2, <V2 '/ 2, ...., and <Vmax' / 2 and in the case of the upper substrate <-│Vmin '/ 2│, <-│V1' / 2│, |, ...., < - | Vmax '/ 2 |, and the liquid crystal distortion significantly decreases.

It can be concluded that the same lens shape can be realized by the applied voltage because the electric fields involved in the liquid crystal deflection are all involved in the vertical electric field,

10 is a graph showing a comparison of transmittance errors (error) according to 1/2 unit lens pitch in the liquid crystal lenses according to the first and second embodiments of the present invention.

First, the transmittance error refers to data obtained by placing a polarizing plate (upper / lower; 45 degrees / 135 degrees) crossing vertically on the upper and lower substrates (upper and lower substrates 90 degrees rubbing) Is a numerical value quantitatively indicating an error level with respect to liquid crystal distortion.

At this time, in the electrically controlled birefringence (ECB) mode, if the liquid crystal distortion does not occur, the transmittance should be 0% regardless of whether a voltage is applied or not. However, when liquid crystal distortion occurs, a region where light is transmitted occurs.

Accordingly, it can be determined that the higher the transmittance in the above structure, the more the liquid crystal distortion occurs.

As can be seen from FIG. 10, it can be seen that the transmittance error is largely generated in the position of the discontinuity of the Fresnel lens (when the voltage difference between adjacent electrodes is large and the liquid crystal distortion occurs severely). In the case of the first embodiment, Is 12.3%, whereas in the case of the second embodiment, the transmittance error is reduced by 4.3% to 60% to 70%.

As a result, the polarizing plate was attached to the liquid crystal lens with the same structure as the actual liquid crystal lens, and the result agrees with the result of observation with a microscope.

While a great many are described in the foregoing description, it should be construed as an example of preferred embodiments rather than limiting the scope of the invention. Therefore, the invention should not be construed as limited to the embodiments described, but should be determined by equivalents to the appended claims and the claims.

105, 205: first substrate 106, 206: liquid crystal layer
107, 207a, 207b: first electrode 108, 208: first alignment film
110, 210: liquid crystal lenses 115, 215: second substrate
118, 218: second orientation film 117a, 117b, 217a, 217b: second electrode
209: first insulation layer 219: second insulation layer
220: light source 240: display panel

Claims (18)

A liquid crystal lens driven according to a voltage application and having a lens function; And
And a display panel positioned below the liquid crystal lens and emitting two-dimensional image information,
In the liquid crystal lens,
A first substrate and a second substrate having a plurality of lens regions having a plurality of partial regions defined and spaced apart from each other;
A liquid crystal layer provided between the first substrate and the second substrate; And
A plurality of upper first electrodes and a plurality of lower first electrodes arranged on the inner surface of the first substrate and spaced apart from each other, and a plurality of lower first electrodes arranged on the inner surface of the second substrate, And an upper second electrode and a plurality of lower second electrodes,
The upper and lower first electrodes and the upper and lower second electrodes are located at the boundaries between the respective partial regions to constitute a shielding electrode having a greater width than the other electrodes,
A voltage having a different polarity and the same absolute value as the common voltage is applied to the upper and lower first electrodes and the upper and lower second electrodes facing each other. The stereoscopic image display apparatus of claim 1, further comprising a light source positioned below the display panel to transmit light to the display panel. The stereoscopic image display apparatus of claim 1, wherein the display panel sequentially and repeatedly arranges first and second image pixels, each of which displays first and second images. The stereoscopic image display apparatus of claim 1, wherein the display panel is one of a liquid crystal display, an organic light emitting display, an electroluminescent display, a plasma image display, and an electroluminescent display. The stereoscopic image display apparatus of claim 1, wherein the plurality of upper and lower first electrodes are spaced apart from each other with a first insulating layer interposed therebetween. The three-dimensional image display apparatus according to any one of claims 1 to 5, wherein the plurality of upper and lower second electrodes are spaced apart from each other with a second insulating layer interposed therebetween. 7. The plasma display panel of claim 6, wherein the plurality of upper first electrodes are disposed to face the plurality of lower second electrodes, and the plurality of lower first electrodes are arranged to face the plurality of upper second electrodes Video display device. The organic electroluminescent device of claim 1, wherein the plurality of upper and lower first electrodes and the plurality of upper and lower second electrodes, which are provided on the first substrate or the second substrate, respectively have different voltages (± Vmin, ± V1, ± V2, ...., &lt; RTI ID = 0.0 &gt; Vmax). &Lt; / RTI &gt; The stereoscopic image display apparatus of claim 1, wherein the shield electrode is not applied with a voltage or 0V is input. The organic electroluminescent device of claim 1, further comprising a first alignment layer and a second alignment layer, respectively, disposed on inner surfaces of the first substrate and the second substrate,
The rubbing direction of the second alignment film is a direction perpendicular to the longitudinal direction of the upper and lower second electrodes and the rubbing direction of the first alignment film is a direction crossing the longitudinal direction of the upper and lower second electrodes, Wherein the three-dimensional image display device has a reverse direction. The stereoscopic image display apparatus of claim 1, wherein the plurality of upper and lower first electrodes and the plurality of upper and lower second electrodes are arranged symmetrically with respect to the lens region and the edge portion of the lens region. The stereoscopic image display apparatus of claim 8, wherein a first voltage (Vmin) corresponding to a threshold voltage is applied to first and second opposing electrodes located at the center of the lens region. 13. The stereoscopic image display apparatus of claim 12, wherein the largest n-th voltage (Vmax) is applied to the first and second opposing electrodes located at the edge portions of the lens regions. The liquid crystal display device according to claim 13, wherein a plurality of opposing first and second electrodes, located between the center of the lens region and the edge portion, are provided between the first voltage (Vmin) and the nth voltage (Vmax) Wherein a voltage having a value gradually increasing from a center of the lens region is applied to the three-dimensional image display apparatus. A first substrate and a second substrate having a plurality of lens regions having a plurality of partial regions defined and spaced apart from each other; And a plurality of upper first electrodes and a plurality of lower first electrodes arranged on the inner surface of the first substrate and spaced apart from each other on the inner surface of the second substrate, Wherein the upper and lower first electrodes and the upper and lower second electrodes are located at a boundary between the upper and lower first electrodes and between the upper and lower second electrodes, A driving method of a liquid crystal lens comprising a shielding electrode having a large width and driven by a voltage applied to a liquid crystal lens having a lens function,
A voltage having a different polarity and the same absolute value as the common voltage is applied to the upper and lower first electrodes and the upper and lower second electrodes which are opposed to each other,
Wherein no voltage is applied to the shield electrode or 0 V is input to the shield electrode. 16. The driving method of a liquid crystal lens according to claim 15, wherein a first voltage (Vmin) corresponding to a threshold voltage is applied to opposing first and second electrodes located at the center of the lens region. 17. The driving method of claim 16, wherein the largest n-th voltage (Vmax) is applied to the opposing first and second electrodes located at the edge portions of the lens regions. The liquid crystal display device according to claim 17, wherein a plurality of opposing first and second electrodes, located between the center and the edge of the lens region, are arranged between the first voltage (Vmin) and the nth voltage (Vmax) Wherein a voltage having a value gradually increasing as the distance from the center of the lens region is applied.

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