Image display unit with controlled electrode sets

This image display unit includes an image display panel and a barrier liquid crystal panel. The barrier liquid crystal panel appropriately controls a potential applied to one or the plurality of electrodes forming the scan-side transparent electrode (105) and the common-side transparent electrode (104) according to an operation mode that is specified, changes a slit width and a slit pitch of the slits (100S, and switches a function to one of the three functions of the 2D display function that emits image light for 2D display from the pixels, the 3D display function that emits image light for 3D display from each of pixels for left eye and pixels for right eye of the pixels, and the viewing angle control function that controls a viewing angle of the image light from the pixels.

TECHNICAL FIELD

The present invention relates to an image display unit, an image display control method, and a non-transitory computer readable medium storing an image display control program, and more specifically, to an image display unit, an image display control method, and a non-transitory computer readable medium storing an image display control program including a two dimension (2D) display function, a three dimension (3D) display function, and a viewing angle control function.

BACKGROUND ART

Three dimension (3D) display techniques to display 3D stereoscopic images in an image display unit (display) of a mobile terminal such as a mobile telephone, a personal computer (PC), and a television include, as is well known in the art, a parallax barrier system, a micro lens system, an integral imaging system and the like. Meanwhile, a viewing angle control technique for controlling the viewing angle of the image display unit includes systems of attaching a commercially available louver (louver sheet that cuts oblique light by slits), overlapping liquid crystals having different directivities, applying contrast reduction to visual angle properties of displayed liquid crystals by grayscale adjustment (Patent literatures 1 and 2).

CITATION LIST

Patent Literature

Patent literature 1: Japanese Unexamined Patent Application Publication No. 2007-293270 (pp. 5-14)Patent literature 2: Published Japanese Translation of PCT International Publication for Patent Application, No. 2008-545994 (pp. 16-24)

SUMMARY OF INVENTION

Technical Problem

Each of the related techniques including the parallax barrier system, the micro lens system, and the integral imaging system that achieve the 3D display function has been established as techniques for achieving 2D/3D switching. However, these related techniques have not been achieved as methods including other functions as well. Further, depending on the applications of the display, there are some cases in which 2D is more convenient or 2D should be used in preference to 3D. Accordingly, with only the 3D display function, the disadvantages are easily raised.

In particular, it is required to assume cases in which mobile terminals such as mobile telephones or notebook personal computers are used in a situation in which there are a large crowd of people (e.g., in trains). However, in such a situation, an e-mail screen displayed on an image display unit (display) of a mobile terminal is frequently peeped at by surrounding people. This often prevents free manipulations of the mobile terminals.

Techniques for solving such problems include applying a technique for controlling the viewing angle to overlap liquid crystals with strong directivity as an image display unit, lowering the display contrast by controlling the grayscale of liquid crystals, attaching a louver (a commercially-available louver sheet including slits formed therein), for example, as described above. However, each of the techniques may cause a further increase in thickness of the image display unit and unguaranteed strength risks. Further, when liquid crystals with wide viewing angle in which grayscale inversion rarely occurs are used, even when the display contrast is lowered by grayscale control, it may often become difficult to greatly change visibility between a front view and an oblique view.

In short, the following problems occur even with the independent implementation of the 3D display technique and the viewing angle control technique as stated above.

The first problem is as follows. First, there are some disadvantages such as reduction in transmittance of the image display unit, an increase in the thickness of the unit and the like depending on the types of structural elements and techniques added to perform switching of 2D/3D display. However, 3D display is not always necessary for all the applications of display and there are some cases in which other effects are prioritized depending on the use conditions. Accordingly, it is more important to increase the effects obtained against such disadvantages.

The second problem is as follows. First, the image display unit using liquid crystals with wide viewing angle originally has a wide viewing angle. Accordingly, when it is tried to prevent viewing from oblique directions by lowering the contrast by grayscale adjustment, it greatly lowers visibility also from a front view. Accordingly, it is impossible to sufficiently obtain the effects of the viewing angle control.

Object of the Present Invention

The present invention has been made in view of the aforementioned circumstances, and aims to provide an image display unit, an image display control method, and an image display control program that include three kinds of functions of a 2D display function, a 3D display function, and a viewing angle control function, and are able to perform flexible switching of these functions.

Solution to Problem

In order to solve the aforementioned problems, the image display unit, the image display control method, and the image display control program according to the present invention mainly employ the following characteristic configurations.

(1) An image display unit according to the present invention is an image display unit at least including: an image display panel that forms pixels to display an image; and a barrier liquid crystal panel that is arranged above the image display panel and forms slits that serve as barriers to shield image light from the pixels of the image display panel, in which the barrier liquid crystal panel forming the slits includes a scan-side transparent electrode and a common-side transparent electrode having sets of electrodes each set formed of an electrode group of one or a plurality of electrodes set to have predetermined one or a plurality of electrode widths corresponding to arrangement intervals of the pixels, the scan-side transparent electrode and the common-side transparent electrode being arranged corresponding to positions of the pixels, and the barrier liquid crystal panel appropriately controls a potential applied to one or the plurality of electrodes forming each of the scan-side transparent electrode and the common-side transparent electrode according to an operation mode that is specified to change a slit width and a slit pitch of the slits formed in the barrier liquid crystal panel, thereby switching to one of three functions of a two dimension (2D) display function that emits image light for 2D display from the pixels of the image display panel as a first mode, a three dimension (3D) display function that emits image light for 3D display from each of pixels for left eye and pixels for right eye of the pixels of the image display panel as a second mode, and a viewing angle control function that controls a viewing angle of the image light from the pixels of the image display panel as a third mode.

(2) An image display control method according to the present invention is an image display control method in an image display unit at least including: an image display panel that forms pixels to display an image; and a barrier liquid crystal panel that is arranged above the image display panel and forms slits that serve as barriers to shield image light from the pixels of the image display panel, in which the barrier liquid crystal panel forming the slits includes a scan-side transparent electrode and a common-side transparent electrode having sets of electrodes each set formed of an electrode group of one or a plurality of electrodes set to have predetermined one or a plurality of electrode widths corresponding to arrangement intervals of the pixels, the scan-side transparent electrode and the common-side transparent electrode being arranged corresponding to positions of the pixels, and the barrier liquid crystal panel appropriately controls a potential applied to one or the plurality of electrodes forming each of the scan-side transparent electrode and the common-side transparent electrode according to an operation mode that is specified to change a slit width and a slit pitch of the slits formed in the barrier liquid crystal panel, thereby switching to one of three functions of a two dimension (2D) display function that emits image light for 2D display from the pixels of the image display panel as a first mode, a three dimension (3D) display function that emits image light for 3D display from each of pixels for left eye and pixels for right eye of the pixels of the image display panel as a second mode, and a viewing angle control function that controls a viewing angle of the image light from the pixels of the image display panel as a third mode.

(3) An image display control program according to the present invention executes the image display control method at least described in the above (2) as a program that can be executed by a computer.

Advantageous Effects of Invention

According to the image display unit, the image display control method, and the image display control program according to the present invention, it is possible to achieve the following effects.

The first effect is as follows. First, the electrode structures of the scan-side transparent electrode and the common-side transparent electrode formed in the barrier liquid crystal panel are such that one or a plurality of electrodes are formed as one set. Further, the electrode group of each set is arranged to correspond to the position of each of the pixels formed in the image display panel, and the method of controlling the electrode group of each set is differentiated according to the operation mode. Accordingly, it is possible to easily switch the mode to any one of the three operation modes of the first mode for 2D display, the second mode for 3D display, and the third mode for viewing angle control.

The second effect is as follows. That is, for example, when they are applied as the image display unit of the parallax barrier system, a barrier liquid crystal panel is added to switch 2D and 3D, which increases the thickness. However, there is no need to increase further thickness to add the viewing angle control function, and the structural risks such as strength as the image display module or the image display apparatus can also be reduced.

The third effect is as follows. That is, for example, when they are applied as the image display unit of the parallax barrier system, it is possible to apply the process for manufacturing the parallax barrier panel, i.e., the barrier liquid crystal panel without greatly changing the conventional technique to add the function for 3D display and the function for viewing angle control to the normal function for 2D display.

The fourth effect is as follows. That is, also in a front view when the 2D display or the viewing angle control is achieved, it is possible to achieve the brightness equal to that in the 3D display depending on the conditions of forming the slits formed in the barrier liquid crystal panel.

DESCRIPTION OF EMBODIMENTS

Hereinafter, with reference to the accompanying drawings, a preferred exemplary embodiment of an image display unit, an image display control method, and an image display control program according to the present invention will be described. In the following description, the image display unit and the image display control method according to the present invention will be described. However, as a matter of course, such an image display control method may be executed as an image display control program that can be executed by a computer, or the image display control program may be recorded in a storage medium that can be read out by a computer.

(Features of the Present Invention)

Prior to the description of the exemplary embodiment of the present invention, the outline of the features of the present invention will be described first. The present invention provides an image display unit, an image display control method, and an image display control program capable of achieving three functions of a 2D display function, a 3D display function, and a viewing angle control function. The present invention includes a barrier liquid crystal panel in which a scan-side transparent electrode and a common-side transparent electrode can be formed, the scan-side transparent electrode and the common-side transparent electrode having electrode structures specific to the present invention and having sets of electrodes, each set including one or a plurality of electrodes whose electrode width is predetermined in consideration of arrangement intervals of pixels, and a method of controlling the electrodes is appropriately switched according to the operations mode to be set, thereby achieving the effect of two functions of the 3D display function and the viewing angle control function in addition to the 2D display function by only ene component of the barrier liquid crystal panel. In particular, the main feature of the present invention is that it is possible to instantaneously switch a mode to any appropriate operation mode of a first mode for normal 2D display, a second mode for 3D display, and a third mode for viewing angle control according to the environment in which a personal computer or a mobile telephone is used and the display performance that is necessary.

More specifically, the present invention has the main feature as follows. When the optical path is designed to allow images having a parallax in right and left eyes to input in order to achieve 3D display, a design for narrowing the viewing angle is also incorporated into the image display unit, thereby enabling switching to the viewing angle control function as well as switching from the 2D display function which is the normal state to the 3D display function. Specifically, according to the present invention, in the image display unit of the parallax barrier system, for example, a slit width, a slit pitch or the like of the parallax barrier is changed by the electrode structure of the barrier liquid crystal panel forming the parallax barrier panel and the switching control method of the applied voltage to control the light amount/angle at which the image light emitted from pixels of the image display panel transmits between slits, thereby being able to arbitrarily switch the 2D display function, the 3D display function, and the viewing angle control function depending on the situations.

To be more specific, the present invention at least includes an image display panel that forms pixels to display an image; and a barrier liquid crystal panel that is arranged above the image display panel and forms slits that serve as barriers to shield image light from the pixels of the image display panel, and the barrier liquid crystal panel forming the slits includes a scan-side transparent electrode and a common-side transparent electrode having sets of electrodes each set formed of an electrode group of one or a plurality of electrodes set to have predetermined one or a plurality of electrode widths corresponding to arrangement intervals of the pixels, the scan-side transparent electrode and the common-side transparent electrode being arranged corresponding to positions of the pixels, and the barrier liquid crystal panel appropriately controls a potential applied to one or the plurality of electrodes forming each of the scan-side transparent electrode and the common-side transparent electrode according to an operation mode that is specified to change a slit width and a slit pitch of the slits formed in the barrier liquid crystal panel, thereby switching to one of three functions of a two dimension (2D) display function that emits image light for 2D display from the pixels of the image display panel as a first mode, a three dimension (3D) display function that emits image light for 3D display from each of pixels for left eye and pixels for right eye of the pixels of the image display panel as a second mode, and a viewing angle control function that controls a viewing angle of the image light from the pixels of the image display panel as a third mode.

In the first mode, each of one or the plurality of electrodes forming each of the scan-side transparent electrode and the common-side transparent electrode is either fixed to a common potential or set to an OFF state, thereby emitting the image light for two dimension (2D) display from the pixels of the image display panel from the barrier liquid crystal panel without forming the slits in the barrier liquid crystal panel. In the second mode, by applying an alternating potential to an electrode predetermined as an electrode for 3D display among the plurality of electrodes forming the scan-side transparent electrode and fixing ene or the plurality of electrodes forming the common-side transparent electrode and rest of the electrodes of the scan-side transparent electrode to a common potential, the slits having a slit width and a slit pitch equal to the arrangement intervals of the pixels are formed in the barrier liquid crystal panel so that side edges of the slits are arranged in positions opposed to centers of the pixels, to emit image light for three dimension (3D) display from each of pixels for left eye and pixels for right eye of the pixels of the image display panel to each direction from the barrier liquid crystal panel. In the third mode, by applying an alternating potential to an electrode predetermined as an electrode for viewing angle control among the plurality of electrodes forming the scan-side transparent electrode and fixing one or the plurality of electrodes forming the common-side transparent electrode and rest of the electrodes of the scan-side transparent electrode to a common potential, the slits having a slit width and a slit pitch narrower than the arrangement intervals of the pixels are formed in the barrier liquid crystal panel, and a viewing angle of the image light from the pixels of the image display panel is limited to a range specified for viewing angle control to emit the image light from the barrier liquid crystal panel.

Configuration Examples of Exemplary Embodiment

Next, one example of an exemplary embodiment of an image display unit according to the present invention will be described. First,FIG. 1is an explanatory view schematically showing the principle of 3D display in an image display unit of a parallax barrier system which is one example of the image display unit according to the present invention. The image display unit of the parallax barrier system includes, as shown inFIG. 1, a barrier liquid crystal panel100which serves as a parallax barrier panel formed above an image display panel10that displays images formed of pixels for right eye10R and pixels for left eye10L. In the barrier liquid crystal panel, slits100S that interrupt light (a slit width w is equal to the arrangement interval of the pixels for right eye10R and the pixels for left eye10L) are arranged at a predetermined pitch (slit pitch p). The image display unit is a technique for inputting images having a parallax (images of the pixels for right eye10R and the pixels for left eye10L) to a right eye201and a left eye202to give the illusion of stereoscopic images, i.e., 3D images.

Next, with reference toFIGS. 3 and 4, a configuration example of the image display unit of the parallax barrier system that displays 3D images as shown inFIG. 1will be described as one example of the image display unit according to the present invention.FIG. 3is a cross-sectional view showing one example of a schematic cross-sectional structure of the image display unit of the parallax barrier system.FIG. 4is a cross-sectional view showing one example of a schematic cross-sectional structure of the barrier liquid crystal panel100in the image display unit of the parallax barrier system shown inFIG. 3.

As shown inFIG. 3, the image display unit of the parallax barrier system includes the image display panel10for image display and the barrier liquid crystal panel100for forming a parallax barrier. The image display panel10includes a structure of holding a liquid crystal layer for display11to form the pixels for right eye10R and the pixels for left eye10L for image display by panel substrates12aand12bmade of glass, acrylic or the like. On the other hand, the barrier liquid crystal panel100holds a barrier liquid crystal layer101to form the slits100S for shielding light by panel substrates102aand102bmade of glass, acrylic or the like. Further, this image display unit includes polarizers103aand103bfor polarizing emitted light provided outside of the panel substrates102aand102b.

The barrier liquid crystal layer101of the barrier liquid crystal panel100shown inFIG. 3is provided between a common-side transparent electrode104and scan-side transparent electrodes105a,105b, and105c, as shown in the cross-sectional view ofFIG. 4. The barrier liquid crystal layer101applies an alternating potential to the scan-side transparent electrodes105a,105b, and105cin a state in which the common-side transparent electrode104is fixed to a common potential, thereby generating a potential difference at intersections between the common-side transparent electrode104and the scan-side transparent electrodes105a,105b, and105c. In this way, slits100Sa,100Sb, and100Sc to shield the image light emitted from the pixels of the image display panel10can be formed.

However, one component of the barrier liquid crystal panel100is added above the image display panel10to form a parallax barrier. This also causes some disadvantages including an increase in thickness as the image display unit and reduction in light transmittance. Therefore, only the effect that 3D images are displayed is not sufficient to make up for these disadvantages.

According to the present invention, as a system which more than compensates for these disadvantages, an electrode structure including sets of electrodes, each set including one or a plurality of electrodes, is employed as the barrier liquid crystal layer101, and a control method of the electrodes is appropriately switched according to an operation mode. Accordingly, it is possible to perform not only a 3D image display function but also a viewing angle control function. Specifically, by appropriately switching the control method of the electrodes according to the operation mode, it is possible to change the slit width/slit pitch/slit thickness/distance between the display surface and the slit surface and the like of the slits100S forming the barrier liquid crystal panel100as desired, and to change the viewing angle of the liquid crystal display screen of the image display unit in principle. Using this principle, for example, switching from a first mode of a normal 2D display function to a second mode of a 3D display function, switching from the second mode of the 3D display function back to the normal 2D display function are made possible. Furthermore, switching to a third mode of the viewing angle control function, switching from the third mode of the viewing angle control function back to the first mode of the normal 2D display function and the like are made possible. This brings about the effect specific to the present invention that it is possible to use three kinds of functions (operation modes) according to the scene.

Next, with reference toFIG. 2, an example of achieving the viewing angle control function to control the viewing angle in the image display unit of the parallax barrier system which is one example of the present invention stated above with reference toFIGS. 3 and 4will be described.FIG. 2is an explanatory view schematically showing the principle for achieving the viewing angle control function in the image display unit of the parallax barrier system.FIG. 2shows an example of changing each of a slit pitch p′ and a slit width w′ of the slits100S formed in the barrier liquid crystal panel100above the image display panel10to ½ (i.e., p′=p/2, w′=w/2) compared to the example of achieving 3D display described with reference toFIG. 1. In short,FIG. 2shows an example of achieving the third mode of the viewing angle control function, as is different from the state of achieving the second mode of the 3D display function shown inFIG. 1.

While the slit pitch p′ and the slit width w′ of the slits100S are halved inFIG. 2compared to those in the 3D display shown inFIG. 1, the density of the number of openings of the slits is doubled. Accordingly, an in-line transmittance of light from the image display panel10(brightness in a front view) is provisionally set presupposing that the in-line transmittance of light is not changed from that inFIG. 1and the optimum input angle to the right eye201and the left eye202adjusted in the 3D display is not changed.

Further, when the slit pitch p′/slit width w′ are changed from the slit pitch p/slit width w in the 3D display shown inFIG. 1, the images displayed in the pixels for right eye10R and the pixels for left eye10L of the image display panel10need to be changed to pixels for both eyes10B so that the same image is input to both of the right eye201and the left eye202or normal images (normal 2D images) are displayed in which the resolution of the image screen is effectively used. If the pixels of the image display panel10are left as in the 3D display as shown inFIG. 1, i.e., the pixels of the image display panel10are left as the pixels for right eye10R and the pixels for left eye10L, two kinds of images displayed by the pixels for right eye10R and the pixels for left eye10L are input into both of the right eye201and the left eye202, and the images are visually recognized as double images.

As stated above, it would be easily imagined that the user's visibility when the normal images (normal 2D images) are displayed in a state in which the slits100S having the slit pitch p′ and the slit width w′ are formed in the barrier liquid crystal panel100above the image display panel10is equal to a viewing image when a louver (louver sheet) is attached to a normal image display panel (image screen).

Next, with reference toFIGS. 5A and 5B, a state of light flux that can transmit between the slits100S when the slit pitch p′ and the slit width w′ of the slits100S formed in the barrier liquid crystal panel100above the image display panel10are halved from the slit pitch p and the slit width w for 3D display (i.e., the pixel arrangement interval w of the pixels for both eyes10B of the image display panel10).FIG. 5AandFIG. 5Bare explanatory views for describing the state of the light flux that transmits between the slits when the slit pitch and the slit width of the slits100S formed in the barrier liquid crystal panel100above the image display panel10are changed.

FIG. 5Ashows a state of the light flux when the second mode for 3D display is specified as the operation mode and the slits100S are formed to have the slit pitch p and the slit width w for 3D display.FIG. 5Bshows a state of the light flux when the third mode for viewing angle control is specified as the operation mode and the slits are formed to have the slit pitch p′ and the slit width w′ in which the slit pitch p and the slit width w for 3D display shown inFIG. 5Aare halved. In order to simplify the description,FIG. 5AandFIG. 5Bshow simplified diagrams in which the panel substrates12aand12band102aand102bfor holding the liquid crystal layer for display11and the barrier liquid crystal layer101, the polarizers103aand103bas described inFIGS. 3 and 4, a refractive index of the liquid crystal and the like are not considered.

As simplified inFIG. 5AandFIG. 5B, an angle θ of the light flux (i.e., a viewing cone indicating the viewing angle) of the light that is emitted from one of the pixels for both eyes10B and is able to transmit between the slits100S is restricted by the slit width w/slit pitch p/slit thickness t/distance d between the pixel and the slit. When the slits100S formed in the barrier liquid crystal panel100are changed from the state shown inFIG. 5Ato the state of the slit width w′/the slit pitch p′/slit thickness t/distance d between the pixel and the slit shown inFIG. 5B, for example, an angle θ′ of the light flux that is able to transmit is changed, which affects the viewing angle at which the light emitted from the liquid crystal layer for display11(image light) can be visibly recognized.

Next, with reference toFIGS. 6 and 7, a relation between the viewing cone θ, i.e., the viewing angle of the light flux from the image display panel10and the slit pitch p, the slit width w, the slit thickness t, the distance d between the pixel and the slit of the slits100S formed in the barrier liquid crystal panel100above the image display panel10will be described.FIG. 6is an explanatory view for simply deriving a relation between the viewing cone θ and the shape of the slits100S formed in the barrier liquid crystal panel100above the image display panel10.FIG. 7is an explanatory view for describing a typical relation between the shape of the slits100S and the viewing cone θ derived inFIG. 6. Both ofFIG. 6andFIG. 7show images for deriving conditions regarding the viewing cone θ (viewing angle).

FIG. 6andFIG. 7each show an example of setting the slit pitch p of the slits100S to be twice as large as the slit width w. The opening width of the barrier liquid crystal panel100that transmits the image light emitted from each pixel of the image display panel10is set to be the same size as the slit width w of the slits100S that shield the image light. In summary, a case is assumed in which both of the slit width w of the slits100S and the opening width w of the barrier liquid crystal panel100are set to have the same size as the cell pitch indicating the arrangement intervals of the pixels of the image display panel10. Further, a side edge of each slit is arranged in a position which is extended vertically from the center of each pixel of the image display panel10.

As shown inFIG. 6, when the distance between the pixel and the slit indicating the distance from the display surface of the image display panel10to the lower end of the slits100is denoted by d, the slit width of the slits100S is denoted by w, the slit pitch of the slits100S is denoted by p=2w, the slit thickness is denoted by t, and the angle between the border line at which the image light emitted from the image display panel10cannot transmit through the barrier liquid crystal panel100and the vertical line to the display surface of the image display panel10, i.e., a viewing cone (viewing angle) is denoted by θ, a parallel distance x from the center O of one of the pixels10ato a side edge P of the N-th (N=1, 2, 3, . . . ) slit100S (the distance measured in parallel with the display surface of the image display panel10, i.e., the distance from the center O of the pixel10ato a location U of the display surface of the image display panel10immediately below the side edge P of the N-th slit100S) is given by the following expression.
x=(N−1)p=2(N−1)w

Meanwhile, from a similar relation between a triangle OPS and a triangle QPT shown inFIG. 6, the following relation can be derived as shown inFIG. 7.
2(N−1)w:w=d:t
∴N=(d+2t)/2t
(However, since N is an integer of one or larger, digits after the decimal point are truncated.)

When the barrier liquid crystal panel100is formed under the conditions shown inFIG. 6, the viewing cone θ (viewing angle) between the center O of one of the pixels10aand the side edge P of the slit100S corresponding to the N-th slit which is counted from the slit100S whose side edge S is positioned on the vertical line of the center O of the pixel10ain the oblique direction is given by the following expression, as shown inFIG. 6andFIG. 7.
tan θ=2(N−1)w/d

Next, with reference toFIG. 8, a relation with the viewing cone θ′ or the viewing angle of the light flux from the image display panel10when the slit pitch p and the slit width w for 3D display shown inFIG. 5Ais halved to the slit pitch p′ and the slit width w′ as shown inFIG. 5Bwill be described.FIG. 8is an explanatory view for simply deriving a relation between the viewing cone θ′ and the shape of the slits100S when the slit pitch and the slit width of the slits100S formed in the barrier liquid crystal panel100above the image display panel10are changed.FIG. 8shows a case in which each of the slit pitch p and the slit width w for 3D display shown inFIG. 6is halved to the slit pitch p′(=p/2) and the slit width w′(=w/2).

FIG. 8also shows an example of setting the slit pitch p′ of the slits100S to be twice as large as the slit width w′. Further, it is assumed that the cell pitch indicating the pixel arrangement interval of the image display panel10has the interval w which is the same to that inFIG. 6. Further, the positional relation between each of the slits100S and each pixel of the image display panel10is, as is different from the case ofFIG. 6, such that the center of each slit100S is formed in a position which is extended vertically from the center of each pixel of the image display panel10.

In the case shown inFIG. 8, as is similar to the case shown inFIG. 6, when the distance between the pixel and the slit indicating the distance from the display surface of the image display panel10to the lower end of the slit100S is denoted by d, the slit width of the slits100S is denoted by w′(=w/2), the slit pitch of the slits100S is denoted by p′=2w′(=w), the slit thickness is denoted by t, and the angle between the border line at which the image light emitted from the image display panel10cannot transmit through the barrier liquid crystal panel100and the vertical line to the display surface of the image display panel10, i.e., a viewing cone (viewing angle), is denoted by θ′, a parallel distance x′ from the center O of one of the pixels10ato a side edge p′ of the N′-th (N′=1, 2, 3, . . . ) slit100S (the distance measured in parallel with the display surface of the image display panel10, i.e., the distance from the center O of the pixel10ato a location U′ of the display surface of the image display panel10immediately below the side edge P′ of the N′-th slit100S) is given by the following expressions.

Meanwhile, from a similar relation between a triangle OP′S and a triangle Q′P′T′, the following relation can be derived.
(4N′−3)w′/2:w′=d:t
∴N′=(2d+3t)/4t
(However, since N′ is an integer of one or larger, digits after the decimal point are truncated.)

When the barrier liquid crystal panel100is formed under the conditions shown inFIG. 8, the viewing cone θ′ (viewing angle) between the center O of one of the pixels10aand the side edge P′ of the slit100S corresponding to the N′-th slit which is counted from the slit100S whose center S is positioned on the vertical line of the center O of the pixel10ain the oblique direction is given by the following expressions, as shown inFIG. 8.

Now, a relation between the viewing cone θ (viewing angle) when the barrier liquid crystal panel100is formed under the conditions shown inFIG. 6andFIG. 7and the viewing cone θ′ (viewing angle) when the barrier liquid crystal panel100is formed under the conditions shown inFIG. 8is as follows.
tan θ:tan θ′=2(N−1)w/d:(4N′−3)w/4d
∴ tan θ/tan θ′=8(N−1)/(4N′−3)

For example, if it is assumed that d=0.5 mm, t=0.02 mm, and w=0.08 mm, the following expressions are obtained.
N=13
N′=13
tan θ=3.84∴θ≈75°
tan θ′=1.96∴θ′≈63°
In summary, for example, when the slit width w′ and slit pitch p′ of the slits100S are halved from the slit width w and the slit pitch p, the viewing angle at which the image light from the pixels of the image display panel10can be visibly recognized can be limited from 75° to 63°.

Further, the viewing cone θ (viewing angle) can be changed not only by changing the slit width w/slit pitch p but also by changing the slit thickness t, the distance d between the pixel and the slit or the like. Furthermore, it is possible to change the viewing cone θ (viewing angle) more efficiently by the combination with a liquid crystal material used for image display, contrast adjustment by grayscale adjustment, luminance adjustment or the like.

In reality, further introduction of parameters such as the refractive index or the transmittance of elements forming the image display unit may have some kind of influence on the viewing cone θ (viewing angle). However, such factors may naturally be treated as variation factors that can be assumed in the exemplary embodiment.

Further, in order to achieve the effect of arbitrarily controlling the viewing cone θ (viewing angle) as stated above, it is required to switch the slit width w/slit pitch p of the slits100S formed in the barrier liquid crystal layer101of the barrier liquid crystal panel100from the state of the 3D display, for example, as described above. One example of a method of switching the second mode for 3D display as shown inFIG. 6to the third mode for viewing angle control as shown inFIG. 8will be described below.

The following electrodes arranged in the barrier liquid crystal layer101of the barrier liquid crystal panel100are the scan-side transparent electrodes105ato105cdescribed with reference toFIG. 4, and are formed as transparent electrodes together with the common-side transparent electrode104in order to transmit the image light emitted from each pixel of the image display panel10. Further, a case is shown in which the barrier liquid crystal layer101of the barrier liquid crystal panel100forms the slits100S in the corresponding areas assuming a case of “normally white”, thereby setting the image light emitted from each pixel of the image display panel10to a non-transmittance state.

FIG. 9is a schematic view showing one example of the electrode structure of the scan-side transparent electrode105to switch the slit width w/slit pitch p of the slits100S formed in the barrier liquid crystal panel100above the image display panel10.FIG. 9shows an example of switching the viewing cone θ and the viewing cone θ′ of the light emitted from the image display surface of the image display panel10by controlling each electrode and switching the slit width w/slit pitch p shown inFIG. 6and the slit width w′/slit pitch p′ shown inFIG. 8, in order to control the viewing angle of the image display unit according to the operation mode of the image display unit.

As shown inFIG. 9, the scan-side transparent electrode105is formed of electrode groups each including a set of five electrodes of one first electrode105-1, two second electrodes105-2aand105-2barranged on the respective sides of the first electrode105-1, and two third electrodes105-3aand105-3barranged outside of the two second electrodes105-2aand105-2b, respectively. The first electrode, the second electrodes, and the third electrodes are connected to a first electrode drive circuit (S1)107-1, a second electrode drive circuit (S2)107-2, and a third electrode drive circuit (S3)107-3for scan-side transparent electrode, respectively.

Note that the electrode width of the first electrode105-1is substantially half (≈w/2) of the slit width w (the arrangement interval w of pixels of the image display panel10) of the slits100S for 3D display shown inFIG. 6. The electrode width of each of the two second electrodes105-2aand105-2band the two third electrodes105-3aand105-3bis substantially ¼ (≈w/4) of the slit width w (the arrangement interval w of pixels of the image display panel10) of the slits100S for 3D display shown inFIG. 6. The opening width of a gap part where there is no electrode, i.e., an area between a set of an electrode group of five electrodes of the scan-side transparent electrode105and a set of the next electrode group, has substantially half (≈w/2) the width of the slit width w (the arrangement interval w of pixels of the image display panel10) of the slits100S shown inFIG. 6. The reason for which the electrode width and the opening width are expressed using the term “substantially” compared to the slit width w (pixel arrangement interval w) is that it is required to form the electrode patterns through an insulating film so as to prevent short-circuit between electrodes, and the electrode width and the opening width are somewhat different from the slit width w (pixel arrangement interval w) depending on the film forming accuracies of the insulating film and the electrode materials.

However, it is desirable to definitely secure a minimum electrode width for forming the slits100S having a constant slit width w as the barrier liquid crystal layer101of the barrier liquid crystal panel100. As shown inFIGS. 10 and 11described later, the first electrode105-1is arranged to substantially cover half (=w/2) the area of the slit width w, and each of the second electrodes105-2aand105-2band the two third electrodes105-3aand105-3bis arranged to substantially cover one quarter (=w/4) of the area of the slit width w.

InFIG. 9, when the mode is switched to the second mode for 3D display as shown inFIG. 6, both of the first electrode drive circuit (S1)107-1and the second electrode drive circuit (S2)107-2are driven that are defined in advance for 3D display according to the instruction to switch the operation mode, to apply an alternating potential to one first electrode105-1having an electrode width of (w/2) and two second electrodes105-2aand105-2beach having an electrode width of (w/4) arranged on the respective sides of the first electrode105-1. In this way, switching can be made so that the width of the slits100S that shield transmission of the image light emitted from each pixel of the image display panel10is substantially equal to the pixel arrangement interval w, and the opening width of the barrier liquid crystal panel100through which the image light transmits is also substantially equal to the pixel arrangement interval w. Further, the slits100smay be formed so that the side edge of each of the slits100S is opposed to the position of the center of each pixel of the image display panel10.

Meanwhile, when the mode is switched to the third mode for viewing angle control as shown inFIG. 8, both of the second electrode drive circuit (S2)107-2and the third electrode drive circuit (S3)107-3are driven that are defined in advance for viewing angle control according to the instruction to switch the operation mode, to apply an alternating potential to the two second electrodes105-2aand105-2beach having an electrode width of (w/4) and the two third electrodes105-3aand105-3beach having an electrode width of (w/4) adjacently arranged outside of the second electrodes105-2aand105-2b, respectively. In this way, switching can be made so that the width of the slits100S that shield transmission of the image light emitted from each pixel of the image display panel10becomes substantially half the width (w/2) of the pixel arrangement interval w, and the opening width of the barrier liquid crystal panel100through which the image light transmits also becomes substantially half the width (w/2) of the pixel arrangement interval w. Further, the slits100S may be formed so that the center of each of the slits100S is opposed to the position of the center of each pixel of the image display panel10.

As described above,FIGS. 10 and 11each show a cross-sectional view of an internal state of the barrier liquid crystal layer101of the barrier liquid crystal panel100when switching between the second mode for 3D display as shown inFIG. 6and the third mode for viewing angle control as shown inFIG. 8is performed.FIG. 10is a cross-sectional view showing one example of an internal state inside the barrier liquid crystal panel100above the image display panel10in the second mode for 3D display as shown inFIG. 6, andFIG. 11is a cross-sectional view showing one example of an internal state inside the barrier liquid crystal panel100above the image display panel10in the third mode for viewing angle control as shown inFIG. 8. InFIG. 10andFIG. 11, an example in which the common-side transparent electrode104is formed as a single electrode pattern is shown for the sake of simplicity. Further, although not shown inFIG. 10andFIG. 11, the positional relation with each pixel of the image display panel10is adjusted so that the center of each pixel of the image display panel10is arranged in the position opposed to the position of the border line between each of second electrodes105-2a1,105-2a2,105-2b1, and105-2b2and each of third electrodes105-3a1,105-3a2,105-3b1, and105-3b2of the barrier liquid crystal panel100.

In the case of the second mode for 3D display as shown inFIG. 6, as described inFIG. 9, an alternating potential is applied to one first electrode105-1ahaving an electrode width of (w/2) and two second electrodes105-2a1and105-2a2each having an electrode width of (w/4) arranged on the respective sides of the first electrode105-1a(the same holds true for105-1b,105-2b1, and105-2b2). Then, the slits100Sa and100Sb that shield the image light emitted from each pixel of the image display panel10are formed to have a slit width w (=w/4+w/2+w/4), as shown in the barrier liquid crystal layer101shown inFIG. 10. Further, the opening part that transmits the image light emitted from each pixel of the image display panel10is formed to have an opening width w (=w/4+w/2+w/4).

Meanwhile, in the case of the third mode for viewing angle control as shown inFIG. 8, as described with reference toFIG. 9, an alternating potential is applied to two second electrodes105-2a1and105-2a2each having an electrode width of (w/4) and two third electrodes105-3a1and105-3a2each having an electrode width of (w/4) adjacently arranged outside of the second electrodes105-2a1and105-2a2, respectively (the same holds true for105-2b1and105-2b2, and105-3b1and105-3b2). Then, as shown in the barrier liquid crystal layer101as shown inFIG. 11, the slits100Sa,100Sb,100Sc, and100Sd that shield the image light emitted from each pixel of the image display panel10are formed to have a slit width w/2 (=w/4+w/4). Further, the opening part that transmits the image light emitted from each pixel of the image display panel10is formed to have an opening width w/2 (=w/2).

FIG. 10andFIG. 11each show an example of forming the common-side transparent electrode104as a single electrode pattern. However, the common-side transparent electrode104opposed to each set of the electrode group of the scan-side transparent electrode105in the barrier liquid crystal panel100may be formed as shown in a schematic view ofFIG. 12. Specifically, by forming the common-side transparent electrode104to have the electrode pattern same to the electrode pattern of the scan-side transparent electrode105in the same direction shown in the schematic view inFIG. 9, it is possible to control the slit width w of the slits100S to be formed with higher accuracy and to obtain preferable switching characteristics.FIG. 12is a schematic view showing one example of the electrode structure of the common-side transparent electrode104for switching the slit width w/slit pitch p of the slits100S formed in the barrier liquid crystal layer101of the barrier liquid crystal panel100.

Specifically, as shown inFIG. 12, the common-side transparent electrode104formed in the same direction as the arrangement direction of the scan-side transparent electrode105is formed of electrode groups each including a set of five electrodes of one first electrode104-1, two second electrodes104-2aand104-2barranged on the respective sides of the first electrode104-1, and two third electrodes104-3aand104-3barranged outside of the two second electrodes104-2aand104-2b, respectively, as is similar to the case of the scan-side transparent electrode105inFIG. 9. The first electrode, the second electrodes, and the third electrodes are connected to a first electrode drive circuit (C1)106-1, a second electrode drive circuit (C2)106-2, and a third electrode drive circuit (C3)106-3for common-side transparent electrode, respectively.

InFIG. 12, the electrode width of the first electrode104-1is substantially half (≈w/2) of the slit width w (the arrangement interval w of pixels of the image display panel10) of the slits100S shown inFIG. 6, as is similar to the case of the scan-side transparent electrode105shown inFIG. 9. The electrode width of each of the two second electrodes104-2aand104-2band the two third electrodes104-3aand104-3bis substantially ¼ (≈w/4) of the slit width w (the arrangement interval w of pixels of the image display panel10) of the slits100S shown inFIG. 6. The opening width of a gap part where there is no electrode, i.e., an area between a set of an electrode group of five electrodes of the common-side transparent electrode and a set of the next electrode group, has substantially half (≈w/2) the width of the slit width w (the arrangement interval w of pixels of the image display panel10) of the slits100S shown inFIG. 6. The reason for which the electrode width and the opening width are expressed using the term “substantially” compared to the slit width w (pixel arrangement interval w) is that, as is similar to the case of the scan-side transparent electrode105shown inFIG. 9, it is required to form the electrode patterns through an insulating film so as to prevent short-circuit between electrodes, and the electrode width and the opening width are somewhat different from the slit width w (pixel arrangement interval w) depending on the film forming accuracies of the insulating film and the electrode materials.

However, also for the common-side transparent electrode104, it is desirable to definitely secure a minimum electrode width for forming the slits100S having a constant slit width w as the barrier liquid crystal layer101of the barrier liquid crystal panel100. Therefore, as is similar to the case of the scan-side transparent electrode105, the first electrode104-1is arranged to substantially cover half (=w/2) the area of the slit width w. Each of the second electrodes104-2aand104-2band the two third electrodes104-3aand104-3bis arranged to substantially cover one quarter (=w/4) of the area of the slit width w.

The electrode arrangement of the common-side transparent electrode104may be simplified compared to the configuration example shown inFIG. 12in consideration of an electrical field applied to the barrier liquid crystal layer101. For example, one first electrode104-1, two second electrodes104-2aand104-2b, and two third electrodes104-3aand104-3bmay be integrally arranged as a solid pattern.

Furthermore, as shown in a schematic view shown inFIG. 13, the common-side transparent electrode104may be formed as a single electrode pattern, and arranged in the direction perpendicular to the arrangement direction of the scan-side transparent electrode105.FIG. 13is a schematic view showing an example different fromFIG. 12, and shows an electrode structure of the common-side transparent electrode104for switching the slit width w/slit pitch p of the slits100S formed in the barrier liquid crystal layer101of the barrier liquid crystal panel100.

InFIG. 13, each electrode set of the common-side transparent electrode104is formed only of one electrode of a single electrode104-4(electrode width is (w/2), for example), and the single electrode104-4is connected to a single electrode drive circuit (C4)106-4. The single electrode104-4that forms the common-side transparent electrode104is arranged in the direction perpendicular to the arrangement direction of the scan-side transparent electrode105, as stated above.

As shown inFIG. 9, the scan-side transparent electrode105is formed of electrode groups each including a set of five electrodes of one first electrode105-1, two second electrodes105-2aand105-2barranged on the respective sides of the first electrode105-1, and two third electrodes105-3aand105-3barranged outside of the two second electrodes105-2aand105-2b, respectively. When the common-side transparent electrode104is formed of electrode groups each including a set of five electrodes of one first electrode104-1, two second electrodes104-2aand104-2barranged on the respective sides of the first electrode104-1, and two third electrodes104-3aand104-3barranged outside of the two second electrodes104-2aand104-2b, respectively, as shown inFIG. 12, as is similar to the scan-side transparent electrode105, the case of switching the mode to the second mode for 3D display and the case of switching the mode to the third mode for viewing angle control may be controlled as follows.

That is, in the case of switching the mode to the second mode for 3D display, both of the first electrode drive circuit (S1)107-1and the second electrode drive circuit (S2)107-2in the scan side are driven to apply an alternating potential to one first electrode105-1having an electrode width of (w/2) and the two second electrodes105-2aand105-2beach having an electrode width of (w/4) arranged on the respective sides of the first electrode105-1. Meanwhile, each of the scan-side third electrode105-3, the first electrode104-1, the second electrode104-2, and the third electrode104-3in the common side is controlled to be fixed to the common potential. Accordingly, it is possible to form the slits100S having a slit width w required for 3D display at the desired positions more accurately compared to the case in which the common-side transparent electrode104is formed as a single electrode pattern.

Furthermore, in the case of switching the mode to the third mode for viewing angle control, both of the second electrode drive circuit (S2)107-2and the third electrode drive circuit (S3)107-3in the scan side are driven to apply an alternating potential to the two second electrodes105-2aand105-2bhaving an electrode width of (w/4) and the two third electrodes105-3aand105-3bhaving an electrode width of (w/4) arranged on outside of the second electrodes105-2aand105-2b, respectively. Meanwhile, each of the scan-side first electrode105-1, the first electrode104-1, the second electrode104-2, and the third electrode104-3in the common side is controlled to be fixed to the common potential. Accordingly, it is possible to form the slits100S having a slit width (w/2) required for viewing angle control at the desired positions more accurately.

When the mode is set to the first mode for normal 2D display in which neither 3D display nor viewing angle control is performed, all the electrodes of the first electrode105-1, the second electrode105-2, and the third electrode105-3in the scan side, and the first electrode104-1, the second electrode104-2, and the third electrode104-3in the common side may be controlled to be fixed to the common potential. Alternatively, in the case of normally white, all the electrodes may be set to the OFF state.

Further, the case of applying the configuration in which the common-side transparent electrode104formed of sets of electrodes, each set including a single electrode104-4is arranged in the direction perpendicular to the arrangement direction of the scan-side transparent electrode105as shown inFIG. 13is similar to the case shown inFIG. 12. In this case, in any of the cases of the second mode for 3D display and the third mode for viewing angle control, the common-side single electrode104-4may be controlled to be fixed to the common potential.

Further, instead of forming the common-side transparent electrode104of electrode groups each including a set of five electrodes of one first electrode104-1, two second electrodes104-2aand104-2barranged on the respective sides of the first electrode104-1, and two third electrodes104-3aand104-3barranged outside of the two second electrodes104-2aand104-2b, respectively, by applying the electrode structure which is the same to that of the opposing scan-side transparent electrode105, as shown inFIG. 12, the common-side transparent electrode104may be formed only of the two second electrodes104-2aand104-2barranged in the same direction as the arrangement direction of the scan-side transparent electrode105, as shown inFIG. 14, in order to simplify the structure of the common-side transparent electrode104.FIG. 14is a schematic view showing an example different fromFIG. 12andFIG. 13, and shows an electrode structure of the common-side transparent electrode104for switching the slit width/slit pitch of the slits100S formed in the barrier liquid crystal layer101of the barrier liquid crystal panel100.

Specifically, each electrode set of the common-side transparent electrode104shown inFIG. 14is formed only of the common-side two second electrodes104-2aand104-2bformed in the same position opposed to the two second electrodes105-2aand105-2bapplied with the alternating potential in any of the second mode for 3D display and the third mode for viewing angle control in the scan-side transparent electrode105. Accordingly, although it depends on the situations of an electrical field, by fixing the common-side second electrodes104-2aand104-2bto the common potential, it is possible to form the slits100S substantially the same to those inFIGS. 10 and 11more accurately than those in the single electrode pattern in any of the second mode for 3D display and the third mode for viewing angle control.

Further, as a configuration example of the barrier liquid crystal panel100, it is also possible to achieve switching control of vertical and horizontal directions of the image light from the image display panel10so as to be able to address with 3D display and switching of vertical and horizontal directions of the viewing angle. More specifically, as shown inFIG. 15, as a set of electrodes of the common-side transparent electrode104, a first single electrode104-4having an electrode width substantially half (w/2) of the slit width w (i.e., the arrangement interval w of pixels of the image display panel10) of the slits100S in the 3D display is formed in each of the positions opposed to the gap parts between electrode sets of the scan-side transparent electrode105shown inFIG. 9(i.e., outside of the scan-side third electrodes105-3aand105-3b). Further, in the similar way, a second single electrode104-5is formed in each of the gap parts between electrode sets of the scan-side transparent electrode105. Then, both of them are arranged so as to be perpendicular to each other as shown inFIG. 16. Accordingly, it is possible to easily address with 3D display and switching of the vertical and horizontal directions of the viewing angle as well.

FIG. 15is a schematic view showing another example of the electrode structures of the scan-side transparent electrode105and the common-side transparent electrode104formed in the barrier liquid crystal layer101of the barrier liquid crystal panel100. Further,FIG. 16is a schematic view showing an example of the electrode structures of the scan-side transparent electrode105and the common-side transparent electrode104when the electrodes having the structures shown inFIG. 15are arranged to be perpendicular to each other in the barrier liquid crystal layer101of the barrier liquid crystal panel100.

First, as shown inFIG. 15, as is similar to the case shown inFIG. 9, the scan-side transparent electrode105is formed of electrode groups each having a set of five electrodes of one first electrode105-1having an electrode width of (w/2), the two second electrodes105-2aand105-2bhaving an electrode width of (w/4) arranged on the respective sides of the first electrode105-1, and the two third electrodes105-3aand105-3bhaving an electrode width of (w/4) arranged outside of the two second electrodes105-2aand105-2b, respectively. The first electrode105-1, the second electrodes105-2aand105-2b, and the third electrodes105-3aand105-3bare connected to the first electrode drive circuit (S1)107-1, the second electrode drive circuit (S2)107-2, and the third electrode drive circuit (S3)107-3for scan-side transparent electrode, respectively.

Meanwhile, the common-side transparent electrode104is formed by arranging the first single electrode104-4having an electrode width of (w/2) in each of the positions opposed to the gap parts having a width (w/2) formed between the sets of the electrode groups of the scan-side transparent electrode105. Then, the first single electrode104-4is connected to the first single electrode drive circuit (C4)106-4for common-side transparent electrode.

Next, in order to address with 3D display and switching of the vertical and horizontal directions of the viewing angle, electrode groups each including a set of five electrodes of one fourth electrode105-4having an electrode width of (w/2), two fifth electrodes105-5aand105-5beach having an electrode width of (w/4) arranged on the respective sides of the fourth electrode105-4, and two sixth electrodes105-6aand105-6beach having an electrode width of (w/4) arranged outside of the two fifth electrodes105-5aand105-5b, respectively, having an electrode structure completely the same to that ofFIG. 15are further added as the scan-side transparent electrode105in the direction perpendicular to the arrangement direction of each electrode of the scan-side transparent electrode105and the common-side transparent electrode104shown inFIG. 15. Further, a second single electrode104-5having an electrode with of (w/2) is added as the common-side transparent electrode104to each of the positions corresponding to the gap parts having a width w/2) formed between the sets of the electrode groups each including the fourth electrode105-4, the fifth electrodes105-5aand105-5b, and the sixth electrodes105-6aand105-6bof the scan-side transparent electrode105that are added. In this way, the electrode structure shown inFIG. 16is formed.

As shown inFIG. 16, the fourth electrode105-4, the fifth electrodes105-5aand105-5b, and the sixth electrodes105-6aand105-6bin the scan side added in the crossing positions are connected to a fourth electrode drive circuit (S4)107-4, a fifth electrode drive circuit (S5)107-5, and a sixth electrode drive circuit (S6)107-6for scan-side transparent electrode that are added, respectively. The common-side second single electrode104-5is connected to a second single electrode drive circuit (C5)106-5that is added.

In summary, inFIG. 16, the scan-side transparent electrode105is formed of electrode groups each including a set of five electrodes of one first electrode105-1, two second electrodes105-2aand105-2barranged on the respective sides of the first electrode105-1, and two third electrodes105-3aand105-3barranged outside of the two second electrodes105-2aand105-2b, respectively. Furthermore, in the direction perpendicular to the direction in which these electrode groups are arranged, electrode groups each including a set of five electrodes of one fourth electrode105-4, two fifth electrodes105-5aand105-5barranged on the respective sides of the fourth electrode105-4, and two sixth electrodes105-6aand105-6barranged outside of the two fifth electrodes105-5aand105-5b, respectively, are arranged. Further, the first single electrode104-4and the second single electrode104-5are arranged as the common-side transparent electrode104so as to be perpendicular to each other in each of the positions opposed to the gap parts between sets of the scan-side transparent electrode105. According to these structures, it is possible to control switching of vertical and horizontal directions of the image light from the image display panel10.

To be more specific, as shown inFIG. 16, by forming the scan-side transparent electrode105and the common-side transparent electrode104in the positions perpendicular to each other, and performing control to select the scan-side transparent electrode105and the common-side transparent electrode104that are in the arrangement direction specified based on the instruction of ON/OFF for switching vertical and horizontal directions, and applying an alternating potential to the scan-side electrode determined according to the instruction of the operation mode of the second mode for 3D display and the third mode for viewing angle control and controlling the rest of the electrodes to be fixed to the common potential, it is possible to appropriately switch control of vertical and horizontal directions of the image light from each pixel of the image display panel10according to the operation mode.

Regarding the process technique (manufacturing technique) for forming the image display unit described above in detail, the image display unit can be manufactured by simple application of any method known to those skilled in the art. Further, the process technique is not directly related to the present invention. Thus, description thereof will be omitted.

Description of Operations of Exemplary Embodiment

Next, with reference to a flowchart shown inFIG. 17, an example of an operation of switching operation modes in the image display unit including three operation modes of the first mode for 2D display which is the normal state, the second mode for 3D display, and the third mode for viewing angle control will further be described.FIG. 17is a flowchart for describing an example of the operation of the image display unit including the three operation modes of the first mode for normal 2D display, the second mode for 3D display, and the third mode for viewing angle control as one example of the image display control method according to the present invention. Further,FIG. 18is a diagram showing control contents of potentials in each step inFIG. 17.

FIG. 17shows a flowchart of one example of a method of controlling switching of the voltage applied to the electrodes (each electrode of the scan-side transparent electrode105, each electrode of the common-side transparent electrode104) when an initial state in which the mode is set to the first mode for normal 2D display is made transition to each state of the second mode for 3D display and the third mode for viewing angle control in the 2D display. Further, the switching control method is distinguished according to the presence or absence of the function of switching vertical and horizontal directions. When the function of switching vertical and horizontal directions is included, the switching control method is further distinguished according to the instruction of ON/OFF of switching of vertical and horizontal directions.

As described above as a configuration example of the exemplary embodiment, various electrode patterns may be selected for the scan-side electrode group forming the scan-side transparent electrode105and the common-side electrode group forming the common-side transparent electrode104. Thus, the flowchart shown inFIG. 17shows a case in which they are formed of maximum number of electrodes as an exemplary embodiment.

Specifically, when the function of switching vertical and horizontal directions of the image light from the image display panel10is included, each set of the electrode group of the scan-side transparent electrode105is formed of the first electrode105-1, the second electrode105-2, the third electrode105-3, the fourth electrode105-4, the fifth electrode105-5, and the sixth electrode105-6, as shown inFIG. 16. The first electrode drive circuit (S1)107-1, the second electrode drive circuit (S2)107-2, the third electrode drive circuit (S3)107-3, the fourth electrode drive circuit (S4)107-4, the fifth electrode drive circuit (S5)107-5, and the sixth electrode drive circuit (S6)107-6are provided as drive circuits to drive the respective electrodes. Meanwhile, when the function of switching vertical and horizontal directions is not included, each set of the electrode group of the scan-side transparent electrode105is formed of the first electrode105-1, the second electrode105-2, and the third electrode105-3, as shown inFIG. 9. InFIG. 16, the first electrode drive circuit (S1)107-1, the second electrode drive circuit (S2)107-2, and the third electrode drive circuit (S3)107-3are provided as drive circuits to drive the respective electrodes.

On the other hand, when the function of switching vertical and horizontal directions of the image light from the image display panel10is included, each set of the electrode group of the common-side transparent electrode104is formed of the first single electrode104-4and the second single electrode104-5, as shown inFIG. 16. The first single electrode drive circuit (C4)106-4and the second single electrode drive circuit (C5)106-5are provided as drive circuits to drive the respective electrodes. When the function of switching vertical and horizontal directions is not included, as shown inFIG. 12, each set of the electrode group of the common-side transparent electrode104is formed of the first electrode104-1, the second electrode104-2, and the third electrode104-3. InFIG. 16, the first electrode drive circuit (C1)106-1, the second electrode drive circuit (C2)106-2, and the third electrode drive circuit (C3)106-3are provided as drive circuits to drive the respective electrodes.

In the flowchart shown inFIG. 17, when the mode is set to the first mode for 2D display which is the normal state in which neither 3D display nor viewing angle control is performed (status ST1), in the case of including the function of switching vertical and horizontal directions, the first electrode drive circuit (S1)107-1, the second electrode drive circuit (S2)107-2, the third electrode drive circuit (S3)107-3, the fourth electrode drive circuit (S4)107-4, the fifth electrode drive circuit (S5)107-5, and the sixth electrode drive circuit (S6)107-6in the scan side, and the first single electrode drive circuit (C4)106-4, and the second single electrode drive circuit (C5)106-5in the common side make all of the first electrode105-1, the second electrode105-2, the third electrode105-3, the fourth electrode105-4, the fifth electrode105-5, and the sixth electrode105-6in the scan side, and the first single electrode104-4and the second single electrode104-5in the common side fixed to the common potential. Otherwise, in the case of normally white, all the scan-side electrodes and the common-side electrodes are controlled to be set to the OFF state (Step St1).

Further, when the mode is set to the first mode for 2D display and the function of switching vertical and horizontal directions is not included, the fourth electrode drive circuit (S4)107-4, the fifth electrode drive circuit (S5)107-5, and the sixth electrode drive circuit (S6)107-6in the scan side are not provided. Thus, the first electrode drive circuit (S1)107-1, the second electrode drive circuit (S2)107-2, and the third electrode drive circuit (S3)107-3in the scan side, and the first electrode drive circuit (C1)106-1, the second electrode drive circuit (C2)106-2, and the third electrode drive circuit (C3)106-3in the common side make all of the first electrode105-1, the second electrode105-2, and the third electrode105-3in the scan side, and the first electrode104-1, the second electrode104-2, and the third electrode104-3in the common side fixed to the common potential. Otherwise, in the case of normally white, all the scan-side electrodes and the common-side electrodes are set to the OFF state (Step St1).

Further, when the first mode for normal 2D display is switched to the second mode for 3D display (status ST2), the presence or absence of the function of switching vertical and horizontal directions is checked. When the function of switching vertical and horizontal directions is not included (Step St2), the fourth electrode drive circuit (S4)107-4, the fifth electrode drive circuit (S5)107-5, and the sixth electrode drive circuit (S6)107-6in the scan side are not provided. Therefore, the first electrode drive circuit (S1)107-1and the second electrode drive circuit (S2)107-2in the scan side are driven to apply an alternating potential to the first electrode105-1and the second electrode105-2in the scan side. Meanwhile, the scan-side third electrode105-3, and the first electrode104-1, the second electrode104-2, and the third electrode104-3in the common side are controlled to be fixed to the common potential by the scan-side third electrode drive circuit (S3)107-3, and the first electrode drive circuit (C1)106-1, the second electrode drive circuit (C2)106-2, and the third electrode drive circuit (C3)106-3in the common side (Step St3,FIG. 18).

Accordingly, as shown inFIG. 1, the slit width of the slits100S that shield transmission of the image light for 3D in the barrier liquid crystal panel100is formed to have the same width as the pixel arrangement interval w. The opening width that transmits the image light for 3D in the barrier liquid crystal layer101of the barrier liquid crystal panel100is also formed to have the same width as the pixel arrangement interval w, and the state is switched to the state for 3D display.

Meanwhile, when the function of switching vertical and horizontal directions is included (Step St4), the instruction of ON/OFF of the function of switching vertical and horizontal directions is further checked. When the instruction of the function of switching vertical and horizontal directions is OFF (Step St5), the first electrode drive circuit (S1)107-1and the second electrode drive circuit (S2)107-2in the scan side are driven to apply an alternating potential to the first electrode105-1and the second electrode105-2in the scan side. Meanwhile, the third electrode105-3, the fourth electrode105-4, the fifth electrode105-5, and the sixth electrode105-6in the scan side, and the first single electrode104-4and the second single electrode104-5in the common side are controlled to be fixed to the common potential by the third electrode drive circuit (S3)107-3, the fourth electrode drive circuit (S4)107-4, the fifth electrode drive circuit (S5)107-5, and the sixth electrode drive circuit (S6)107-6in the scan side, and the first single electrode drive circuit (C4)106-4and the second single electrode drive circuit (C5)106-5in the common side (Step St6,FIG. 18).

Accordingly, the slit width of the slits100S that shield transmission of the image light for 3D in the barrier liquid crystal panel100is formed to have the same width as the pixel arrangement interval w in the horizontal direction of the image display unit, for example. The opening width that transmits the image light for 3D in the barrier liquid crystal layer101of the barrier liquid crystal panel100is also formed to have the same width as the pixel arrangement interval w, and the state is switched to the state for 3D display.

Further, when the instruction of the function of switching vertical and horizontal directions is ON (Step St7), in order to switch control of the vertical and horizontal directions of the image light from the image display panel10, the fourth electrode drive circuit (S4)107-4and the fifth electrode drive circuit (S5)107-5in the scan side are driven to apply an alternating potential to the fourth electrode105-4and the fifth electrode105-5in the scan side. Meanwhile, the first electrode105-1, the second electrode105-2, the third electrode105-3, and the sixth electrode105-6in the scan side, and the first single electrode104-4and the second single electrode104-5in the common side are controlled to be fixed to the common potential by the first electrode drive circuit (S1)107-1, the second electrode drive circuit (S2)107-2, the third electrode drive circuit (S3)107-3, and the sixth electrode drive circuit (S6)107-6in the scan side, and the first single electrode drive circuit (C4)106-4and the second single electrode drive circuit (C5)106-5in the common side (Step St8,FIG. 18).

Accordingly, the slit width of the slits100S that shield transmission of the image light for 3D in the barrier liquid crystal panel100is formed to have the same width as the pixel arrangement interval w in the vertical direction of the image display unit, for example. The opening width that transmits the image light for 3D in the barrier liquid crystal layer101of the barrier liquid crystal panel100is also formed to have the same width as the pixel arrangement interval w, and the state is switched to the state for 3D display.

Further, when the first mode for normal 2D display is switched to the third mode for viewing angle control (status ST3), as is similar to switching to the second mode for 3D display, the presence or absence of the function of switching vertical and horizontal directions is checked. When there is no function of switching vertical and horizontal directions (Step St9), the fourth electrode drive circuit (S4)107-4, the fifth electrode drive circuit (S5)107-5, and the sixth electrode drive circuit (S6)107-6in the scan side are not included. Thus, the second electrode drive circuit (S2)107-2and the third electrode drive circuit (S3)107-3in the scan side are driven to apply an alternating potential to the second electrode105-2and the third electrode105-3in the scan side. Meanwhile, the scan-side first electrode105-1, and the first electrode104-1, the second electrode104-2, and the third electrode104-3in the common side are controlled to be fixed to the common potential by the scan-side first electrode drive circuit (S1)107-1, and the first electrode drive circuit (C1)106-1, the second electrode drive circuit (C2)106-2, and the third electrode drive circuit (C3)106-3in the common side (Step St10,FIG. 18).

Accordingly, as shown inFIG. 2, the slit width of the slits100S that shield transmission of the image light for 2D in the barrier liquid crystal panel100is formed to be half the width (w/2) of the pixel arrangement interval w. The opening width that transmits the image light for 2D in the barrier liquid crystal layer101of the barrier liquid crystal panel100is also formed to be half the width (w/2) of the pixel arrangement interval w, and the state is switched to the state for viewing angle control in which the viewing angle is further limited compared to the first mode.

Meanwhile, when the function of switching vertical and horizontal directions is included (Step St11), as is similar to the case of switching to the second mode for 3D display, the instruction of ON/OFF of the function of switching vertical and horizontal directions is further checked. When the instruction of the function of switching vertical and horizontal directions is OFF (Step St12), the second electrode drive circuit (S2)107-2and the third electrode drive circuit (S3)107-3in the scan side are driven to apply an alternating potential to the second electrode105-2and the third electrode105-3in the scan side. Meanwhile, the first electrode105-1, the fourth electrode105-4, the fifth electrode105-5, and the sixth electrode105-6in the scan side, and the first single electrode104-4and the second single electrode104-5in the common side are controlled to be fixed to the common potential by the first electrode drive circuit (S1)107-1, the fourth electrode drive circuit (S4)107-4, the fifth electrode drive circuit (S5)107-5, and the sixth electrode drive circuit (S6)107-6in the scan side, and the first single electrode drive circuit (C4)106-4and the second single electrode drive circuit (C5)106-5in the common side (Step St13,FIG. 18).

Accordingly, the slit width of the slits100S that shield transmission of the image light for 2D in the barrier liquid crystal panel100is formed to be half the width (w/2) of the pixel arrangement interval w in the horizontal direction of the image display unit, for example. The opening width that transmits the image light for 2D in the barrier liquid crystal layer101of the barrier liquid crystal panel100is also formed to be half the width (w/2) of the pixel arrangement interval w, and the state is switched to the state for viewing angle control in which the viewing angle is further limited compared to the first mode.

Meanwhile, when the instruction of the function of switching vertical and horizontal directions is ON (Step St14), in order to switch control of the vertical and horizontal directions of the image light from the image display panel10, the fifth electrode drive circuit (S5)107-5and the sixth electrode drive circuit (S6)107-6in the scan side are driven to apply an alternating potential to the fifth electrode105-5and the sixth electrode105-6in the scan side. Meanwhile, the first electrode105-1, the second electrode105-2, the third electrode105-3, and the fourth electrode105-4in the scan side, and the first single electrode104-4and the second single electrode104-5in the common side are fixed to the common potential by the first electrode drive circuit (S1)107-1, the second electrode drive circuit (S2)107-2, the third electrode drive circuit (S3)107-3, and the fourth electrode drive circuit (S4)107-4in the scan side, and the first single electrode drive circuit (C4)106-4and the second single electrode drive circuit (C5)106-5in the common side (Step St15,FIG. 18).

Accordingly, the slit width of the slits100S that shield transmission of the image light for 2D in the barrier liquid crystal panel100is formed to be half the width (w/2) of the pixel arrangement interval w in the vertical direction of the image display unit, for example. The opening width that transmits the image light for 2D in the barrier liquid crystal layer101of the barrier liquid crystal panel100is also formed to be half the width (w/2) of the pixel arrangement interval w, and the state is switched to the state for viewing angle control in which the viewing angle is further limited compared to the first mode.

Description of Effects of Exemplary Embodiment

As described above in detail, the exemplary embodiment achieves the effects as follows.

The first effect is as follows. The electrode structures of the scan-side transparent electrode105and the common-side transparent electrode104formed in the barrier liquid crystal panel100are such that one or a plurality of electrodes are formed as one set. Further, the electrode group of each set is arranged so as to correspond to the position of the center of each of the pixels of the image display panel10, and the method of controlling the electrode group of each set is differentiated according to the operation mode. Accordingly, it is possible to easily switch the mode to any one of the three operation modes of the first mode for 2D display, the second mode for 3D display, and the third mode for viewing angle control.

The second effect is as follows. For example, when the exemplary embodiment is applied as the image display unit of the parallax barrier system as described in the aforementioned exemplary embodiment, the barrier liquid crystal panel100is added to perform switching between 2D and 3D. Although this increases the thickness, there is no need to increase further thickness to further add the viewing angle control function, and the structural risks such as strength as the image display module or the image display apparatus can also be reduced.

The third effect is as follows. For example, when the exemplary embodiment is applied as the image display unit of the parallax barrier system as described in the aforementioned exemplary embodiment, it is possible to apply the manufacturing process itself of the parallax barrier panel, i.e., the barrier liquid crystal panel without greatly changing the conventional technique to add the function for 3D display and the function for viewing angle control to the normal function for 2D display.

The fourth effect is as follows. That is, also in a front view when the 2D display or the viewing angle control is achieved, it is possible to achieve the brightness equal to that in the 3D display depending on the conditions of forming the slits100S formed in the barrier liquid crystal panel100.

The configurations of the preferred exemplary embodiment of the present invention have been described above. However, it should be noted that the exemplary embodiment is merely an example of the present invention and is not intended to limit the present invention. Those skilled in the art would easily understand that various modifications can be made according to the specific application without departing from the spirit of the present invention.

While the present invention has been described as a hardware configuration in the exemplary embodiment stated above, the present invention is not limited to this. The present invention may achieve any desired processing by causing a central processing unit (CPU) to execute a computer program. Further, the aforementioned program can be stored and provided to a computer using any type of non-transitory computer readable media. Non-transitory computer readable media include any type of tangible storage media. Examples of non-transitory computer readable media include magnetic storage media (such as flexible disks, magnetic tapes, hard disk drives, etc.), optical magnetic storage media (e.g. magneto-optical disks), CD-ROM (Read Only Memory), CD-R, CD-R/W, and semiconductor memories (such as mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory), etc.). The program may be provided to a computer using any type of transitory computer readable media. Examples of transitory computer readable media include electric signals, optical signals, and electromagnetic waves. Transitory computer readable media can provide the program to a computer via a wired communication line (e.g. electric wires, and optical fibers) or a wireless communication line.

While the present invention has been described above with reference to the exemplary embodiment, the present invention is not limited to the above exemplary embodiment. The configurations and details of the present invention can be modified in various manners which can be understood by those skilled in the art within the scope of the invention.

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2011-048131, filed on Mar. 4, 2011, the disclosure of which is incorporated herein in its entirety by reference.

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