JP4094513B2 - Barrier element and stereoscopic image display apparatus including the same - Google Patents

Description

  The present invention relates to a barrier element capable of viewing a three-dimensional image without requiring special glasses and capable of displaying a two-dimensional image, and a stereoscopic image display apparatus including the barrier element.

  Conventionally, various methods have been proposed as a method for displaying a three-dimensional image without using glasses. As one of such methods, a lenticular lens method is known. The lenticular incorporates a large number of small lenses, and uses the lenticular to control the traveling direction of light so that the right eye image reaches the right eye and the left eye image reaches the left eye. However, the lenticular lens system generally has a problem that it is not possible to switch between a three-dimensional image and a two-dimensional image.

  As another 3D image display method, a parallax (parallax) barrier method has been proposed. In this system, a fine stripe-shaped light shielding slit called a barrier stripe is used. For example, a striped right-eye image and left-eye image are alternately displayed at positions spaced apart by a certain distance behind the light-shielding slit, and only the right-eye image is displayed on the viewer's right eye by viewing through the light-shielding slit. Set to deliver only the left eye image to the left eye. Thereby, a stereoscopic image can be seen without glasses. In such a system, the light shielding part and the transmission part as a barrier are fixed. Therefore, when trying to view a two-dimensional image, there is a problem that a bright two-dimensional image cannot be obtained because the light-shielding portion becomes an obstacle.

  Patent Document 1 discloses a method of stereoscopically displaying a three-dimensional image by displaying a three-dimensional image on one liquid crystal display panel and electronically generating a barrier stripe image using the other liquid crystal display panel. ing. According to this method, when displaying a two-dimensional image, the barrier stripe image can be erased and displayed so as not to obstruct. Therefore, a bright and easy-to-see two-dimensional image can be displayed, and switching between the three-dimensional image and the two-dimensional image is possible. In the case of such a technique, it is necessary to pattern the transparent electrode shape of the liquid crystal display panel for displaying the barrier stripe image according to the shape of the barrier stripe. In particular, since the patterning of the transparent electrode needs to be performed by etching or the like, there is a problem that when a fine electrode pattern is formed, disconnection often occurs and the yield decreases. Furthermore, when this method is applied to applications such as notebook personal computers, monitors, and televisions, it is necessary to pattern transparent electrodes made of ITO (indium tin oxide) or the like in stripes. A voltage drop due to electrode wiring resistance becomes a problem, and degradation of display quality due to gradation becomes a problem.

  Patent Document 2 discloses a method for stereoscopically viewing an image by generating a barrier stripe by combining a liquid crystal panel using a common electrode and a patterned polarizing element without the need for patterning a transparent electrode. . 9 and 10 are cross-sectional views illustrating an outline of the three-dimensional image display device described in Patent Document 2. FIG. A three-dimensional image display device disclosed in Patent Document 2 will be described with reference to FIG.

  The liquid crystal panel 100 for generating the barrier stripe is provided on the front surface of the image display means 200 including the pixel portion 101 for the right eye image and the pixel portion 102 for the left eye image. The liquid crystal layer 33 is sandwiched between substrates 31 and 32 made of, for example, glass. A polarizing plate 34 is provided between the lower substrate 32 and the image display means 200.

  A patterned polarizing plate 300 is arranged on the upper surface of the upper substrate 31. The polarizing plate 300 includes a polarizing film (hereinafter referred to as “PVA film”) 50 made of polyvinyl alcohol, which is divided into a polarizing region 51 having a polarizing function and a non-polarizing region 52 having no polarizing function. Yes. The PVA film 50 is sandwiched between transparent support plates 60 made of, for example, triacetyl acetate (hereinafter referred to as “TAC”) or glass. Thereby, the patterned polarizing plate 300 is formed. In the figure, A is the transmission axis of the upper polarizing plate 300, and B is the transmission axis of the lower polarizing plate 34.

  FIG. 9 is a cross-sectional view showing the display principle of the three-dimensional image display by the three-dimensional image display device described in Patent Document 2. The display principle of a three-dimensional image will be described with reference to FIG. The polarizing direction of the polarizing plate 34 and the polarizing direction in the polarizing region 51 of the polarizing plate 300 are set to be orthogonal to each other. By applying a voltage to the liquid crystal panel 100 and causing the liquid crystal molecules in the liquid crystal layer 33 to rise, the polarizing region 51 becomes a barrier. Further, the non-polarization region 52 transmits light regardless of the polarization direction. Therefore, by forming the polarization region 51 to be a parallax barrier with respect to the pixel portions 101 and 102, it is possible to display a three-dimensional image by the ballarax barrier method.

  FIG. 10 is a cross-sectional view showing the display principle of the two-dimensional image display by the three-dimensional image display device described in Patent Document 2. The principle of displaying a two-dimensional image will be described with reference to FIG. When no voltage is applied to the liquid crystal panel 100, the polarizing region 52 is in a state where light can be transmitted therethrough. Therefore, light is transmitted from the entire surface of the liquid crystal panel 100 without the polarizing region 52 being a barrier. In such a state, a two-dimensional image can be obtained by making the display image of the pixel units 101 and 102 a two-dimensional image.

According to the technique of Patent Document 2, even if the barrier stripe pattern is fine, the electrode pattern need not be etched by patterning the polarizing plate 300. Accordingly, a barrier stripe pattern having a complicated shape can be formed without causing a disconnection failure, and a stereoscopic video display device capable of electrically switching between a two-dimensional image and a three-dimensional image can be provided.
JP-A-5-122733 (publication date May 18, 1993) JP-A-8-76110 (publication date March 22, 1996)

  However, the polarizing plate 300 disclosed in Patent Document 2 has the following manufacturing defects. A manufacturing process of the polarizing plate 300 will be described. The stretched PVA film 50 is attached to a transparent support 60 such as glass or TAC, and a resist film is formed on the PVA film 50. After masking the portion 52 where the polarizing function is not desired, the exposed portion 51 of the PVA film 50 is dyed with iodine or a dichroic dye that imparts the polarizing function.

  An organic polymer (resin) film, particularly a PVA film 50 used as a polarizing film, is easily expanded and contracted with respect to heat, moisture, and the like, and has a large dimensional variation, compared to an inorganic material such as glass. Therefore, it goes without saying that PVA is attached to an organic polymer substrate such as TAC via an adhesive, and even when it is attached to a glass substrate with small dimensional fluctuations, the size of the adhesive changes due to the lateral displacement of the adhesive layer. There is a risk.

  When a resist pattern is formed on a PVA film by a photolithography method, there are a resist peeling step using a solvent such as an aqueous caustic soda solution and a heating step such as resist calcination. For this reason, the final dimension of the actual resist pattern is likely to fluctuate with respect to the design dimension of resist (barrier) patterning, resulting in deviation from the barrier pattern design dimension. In addition, the polarizing plate 300, the liquid crystal panel 100, and the image display means 200 for displaying the left and right eye images on which the barrier stripe pattern is formed must be accurately arranged at predetermined positions, and the barrier stripe pattern is fine. The more accurate the position accuracy, the more severe the position accuracy.

  When the PVA film 50 having a large dimensional variation is patterned as described above, the dimensional variation is large, resulting in a deviation in the finished dimension with respect to the design dimension. Therefore, the dimensional accuracy of the barrier stripe pattern is deteriorated, and further, the fitting accuracy between the barrier stripe pattern and the video display pixel pattern is deteriorated, so that there is a problem that 3D image display is adversely affected. Furthermore, when a large screen size is used for a notebook personal computer or a monitor, it is extremely susceptible to dimensional accuracy, and it is difficult to obtain a good three-dimensional image.

  Moreover, in order to dye | stain with the iodine or dichroic dye on the PVA film 50 patterned by the resist, it is necessary to introduce the new process which is not in the manufacturing process of the conventional liquid crystal display device, and manufacture is complicated. There is another problem of becoming.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to form a fine barrier pattern with high dimensional accuracy by using a conventional manufacturing process of a liquid crystal display device and Display and non-display, and switching between 3D and 2D images, with no significant image degradation due to gradations and improved reliability, especially in medium to large 3D display devices It is an object of the present invention to provide a barrier element that performs the above and a stereoscopic image display device including the same.

  In order to solve the above problems, a barrier element according to the present invention is arranged on the front or back of a video display element in which a plurality of video display units for displaying images are repeatedly arranged in a certain order on a plane. In addition, a light-shielding unit that controls on / off of light transmission of the image from each video display unit and a transmission unit that constantly transmits the light are alternately and repeatedly transmitted from each video display unit in a specific direction. In the barrier element that changes the observable position where the image can be seen for each video display unit by transmitting only the light that does not transmit in other directions, a liquid crystal layer is formed in the light shielding unit, The transmissive part is characterized by having a light-transmissive transmissive layer having a substantially isotropic refractive index.

  In addition to the above-described configuration, the barrier element according to the present invention includes at least two or more types in which the transmission layer includes a maximum thickness region having the same thickness as the thickness of the liquid crystal layer and a thin region having a smaller thickness. It is characterized by being formed by a region having a thickness of.

  In addition to the above configuration, the barrier element according to the present invention includes two types of the video display units, and the images displayed by the video display units are a right-eye image and a left-eye image in a three-dimensional display of the same image. It is characterized by being an image.

  In addition to the above-described configuration, the barrier element according to the present invention is characterized in that the images displayed by the video display units are independent images.

In addition to the above configuration, the barrier element according to the present invention has the above-mentioned liquid crystal layer, where dmax is the maximum thickness region, dmin is the thickness of the thin region, and Δn is the birefringence of the liquid crystal layer. The retardation of the layer is 10 nm ≦ (dmax−dmin) Δn ≦ 60 nm
It is characterized by being.

  In addition, the stereoscopic video display device according to the present invention includes two types of video display units that are a left-eye pixel unit and a right-eye pixel unit, respectively, and a barrier element. A stereoscopic image display apparatus that switches between a three-dimensional image and a two-dimensional image and displays the three-dimensional image by providing the barrier element according to claim 1 and switching light shielding / transmission in a liquid crystal layer of the barrier element according to a given electric signal. It is characterized by switching between a two-dimensional image and a two-dimensional image.

  As described above, in the barrier element according to the present invention, a liquid crystal layer is formed in the light-shielding portion, and a light-transmitting transmissive layer having a substantially isotropic refractive index is formed in the transmissive portion. Therefore, at the time of three-dimensional image display, the liquid crystal layer takes a certain alignment state so that light is not transmitted and functions as a light shielding portion, while the transmission layer transmits light and functions as a transmission portion. Therefore, 3D image display can be performed. In the case of two-dimensional image display, light is transmitted by the liquid crystal layer having another alignment state, and the transmission layer also transmits light and functions as a transmission part. Therefore, two-dimensional image display can be performed. In other words, the three-dimensional image and the two-dimensional image can be switched and displayed by only changing the applied signal with one apparatus.

  In other words, unlike the case of Patent Documents 1 and 2, both the light shielding part and the transmissive part are configured by a liquid crystal display element, and the transmissive part has a substantially isotropic refractive index and a light-transmissive transmission. It consists of layers.

  This makes it possible to manufacture with high accuracy using a conventional manufacturing process of a liquid crystal display device without introducing a new manufacturing process.

  Therefore, it is possible to form a fine barrier pattern with high dimensional accuracy by using the manufacturing process of the conventional liquid crystal display device, and to switch and display a 3D image and a 2D image without image deterioration due to gradation. There is an effect that a barrier element can be obtained.

  The barrier element includes a pair of transparent electrode substrates each having a transparent electrode formed thereon, and a pair of polarizing plates sandwiching the pair of transparent electrode substrates. It may be a barrier element in which a light shielding part that separates light in one direction and light in the other direction, and a transmission part that transmits light in one direction and light in the other direction, respectively. .

  In addition to the above-described configuration, the barrier element according to the present invention includes at least two or more types in which the transmission layer includes a maximum thickness region having the same thickness as the thickness of the liquid crystal layer and a thin region having a smaller thickness. Therefore, the gap of the liquid crystal layer of the barrier element can be uniformly maintained as a spacer that keeps the gap between the bottom plate and the top plate of the liquid crystal layer constant by the maximum thickness region. On the other hand, since the arrangement ratio of the spacers can be suppressed by the thin region, the generation of bubbles under an external impact or a low temperature environment can be suppressed. Therefore, in addition to the effect of the above configuration, there is an effect that both the gap of the liquid crystal layer and the generation of bubbles can be suppressed.

  In addition to the above configuration, the barrier element according to the present invention includes two types of the video display units, and the images displayed by the video display units are a right-eye image and a left-eye image in a three-dimensional display of the same image. Since it is an image, in addition to the effect by the above configuration, there is an effect that a good three-dimensional image display can be performed.

  Further, in the barrier element according to the present invention, in addition to the above-described configuration, the image displayed by each video display unit is an independent image. For example, the image is an image for the left observer. It is an image for right observers. Also, for example, an upper observer image and a lower observer image. Three or more people may be used. Therefore, in addition to the effect of the above configuration, there is an effect that different images can be satisfactorily shown to observers at different positions with one display device.

In addition to the above configuration, the barrier element according to the present invention has the above-mentioned liquid crystal layer, where dmax is the maximum thickness region, dmin is the thickness of the thin region, and Δn is the birefringence of the liquid crystal layer. The retardation of the layer is 10 nm ≦ (dmax−dmin) Δn ≦ 60 nm
Therefore, it is possible to suppress a decrease in transmittance due to an increase in birefringence due to retardation of the liquid crystal layer. Therefore, in addition to the effect of the above configuration, there is an effect that it is possible to suppress a decrease in display quality.

  A stereoscopic image display device according to the present invention includes the above-described barrier element, and switches between a three-dimensional image and a two-dimensional image by switching light shielding / transmission in the liquid crystal layer of the barrier element in accordance with an applied electric signal. Since display is performed, when a three-dimensional image is displayed, light is not transmitted by taking a certain alignment state of the liquid crystal layer and functions as a light shielding portion, while the transmission layer transmits light and functions as a transmission portion. Therefore, 3D image display can be performed. In the case of two-dimensional image display, light is transmitted by the liquid crystal layer having another alignment state, and the transmission layer also transmits light and functions as a transmission part. Therefore, two-dimensional image display can be performed. In other words, the three-dimensional image and the two-dimensional image can be switched and displayed by only changing the applied signal with one apparatus.

  Therefore, it is possible to form a fine barrier pattern with high dimensional accuracy by using the manufacturing process of the conventional liquid crystal display device, and to switch and display a 3D image and a 2D image without image deterioration due to gradation. There is an effect that a stereoscopic image display device including a barrier element can be obtained.

  The parallax barrier element of the present invention includes a pair of transparent electrode substrates each having a transparent electrode formed thereon, and a pair of polarizing plates sandwiching the pair of transparent electrode substrates, and a gap between the pair of transparent electrode substrates. A parallax barrier element in which a barrier light-shielding portion that separates light in one direction and light in the other direction and a transmission portion that transmits light in the one direction and light in the other direction are formed A liquid crystal layer is formed on the barrier light-shielding portion, and a transparent resin layer having a refractive index substantially isotropic and having a film thickness of at least two or more types is formed on the transmission portion. It can also be comprised so that it may be formed.

  Since the parallax barrier device of the present invention is divided into a region filled with a light-transmitting resin and a region filled with a liquid crystal material having refractive index anisotropy. The light beam incident on the parallax barrier element is linearly polarized by the polarizing plate and then enters a region filled with a light-transmitting resin having a substantially isotropic refractive index. Even if this polarized light passes through the translucent resin layer, it maintains the polarization state as it is.

  On the other hand, in a region filled with a liquid crystal material having refractive index anisotropy, the polarization state of polarized light incident on the liquid crystal layer changes according to the alignment state of the liquid crystal layer. Therefore, the polarization state can be separated according to the region divided by the above configuration, and the transmission part and the barrier light shielding part can be formed by setting the pair of polarizing plates to have an appropriate axial arrangement. it can.

  In this specification, “image light” includes not only light emitted from the pixel portion of the display element but also light that is incident on the pixel portion of the display element to form an image.

  The parallax barrier element is not limited to use in a three-dimensional image display device. For example, the parallax barrier element is a dual view display (right observer and left Different images can be displayed for each observer). Of course, it is possible not only to separate and transmit light in the left-right direction but also to separate light in the up-down direction.

  The light in the one direction may be light for the left eye image, and the light in the other direction may be light for the right eye image.

  The light in the one direction may be light of the left observer image, and the light in the other direction may be light of the right observer image.

  The light in the one direction may be light of the upper observer image, and the light in the other direction may be light of the lower observer image.

  According to the parallax barrier element of the present invention, a fine barrier pattern can be formed with high dimensional accuracy using a conventional manufacturing process of a liquid crystal display device. Further, according to the parallax barrier element of the present invention, since the barrier pattern can be electrically displayed / non-displayed, by combining with a video display unit having a left-eye pixel unit and a right-eye pixel unit, A stereoscopic video display device in which a 3D image and a 2D image are switched and displayed is obtained.

  Here, the translucent resin layer used for the transmissive portion can be configured to have a function of uniformly maintaining the gap of the liquid crystal layer of the parallax barrier element in addition to the above function.

  In general, as a means to maintain the gap of liquid crystal display devices, a method of dispersing spherical spacer beads on one substrate, and using a photosensitive resin, a spacer on a pillar is formed at a predetermined position by photolithography. And how to do it.

  Especially for medium to large applications, it is difficult to evenly spread spherical spacer beads in the plane, and it is difficult to keep the gap in the plane uniform. The column spacers made of photosensitive resin are often used.

In the case of the above-mentioned columnar spacer made of a photosensitive resin, the hardness is higher than that of the spherical spacer bead, it is difficult to elastically deform against external stress, and furthermore, about 1 / compared with the thermal expansion coefficient (10 ⁻⁴ order) of the liquid crystal material. It has a characteristic of a thermal expansion coefficient of 10 (10 ⁻⁵ order).

  Therefore, the cell thickness uniformity improves as the arrangement ratio of the columnar spacers arranged in the plane increases.

  However, due to the material characteristics of the columnar spacers as described above, there are problems such that bubbles are likely to be generated by an external impact and low-temperature bubbles are generated in a low-temperature environment. Therefore, generally, about 1 to 3 columnar spacers of about 10 μm are arranged for RGB pixels of a liquid crystal display device, and the arrangement ratio of the columnar spacers is designed to be extremely low compared to the display area. Has been.

  In the case of the parallax barrier element of the present invention, since the photosensitive resin is arranged in the entire transmission region, the arrangement ratio of the photosensitive translucent resin layer in the display surface becomes extremely high. For this reason, when the photosensitive resin layer is formed with a single film thickness, the entire transmission region functions as a columnar spacer. It is preferable to take a separate measure against the occurrence.

  On the other hand, in the parallax barrier element of the present invention, the photosensitive translucent resin layer formed in the transmissive region is formed of at least two types of film thickness regions, so that the parallax barrier device is formed only in the maximum film thickness region. Since the gap of the liquid crystal layer can be maintained, the above-mentioned reliability problem can be solved without any additional measures by arbitrarily changing the ratio of the maximum film thickness region to the other thin film thickness region. The point can be solved.

  That is, in the regions of different film thicknesses formed on the photosensitive translucent resin layer formed in the transmission region, the maximum film thickness region has both the function of the transmission window and the function of maintaining the gap of the liquid crystal layer. Since the low-thickness region has only the function of the transmission window, the problem of reliability can be solved.

In addition, there is a gap between the low thickness region (thickness = dmin) of the photosensitive translucent resin layer having at least two types of thickness regions formed in the transmission portion formed on one substrate and the counter substrate. Alternatively, the liquid crystal layer can be filled by a film thickness difference (dmax−dmin) from the maximum film thickness region (film thickness = dmax). In this case, as the gap of the liquid crystal layer filled in the gap increases, the birefringence due to the retardation ((dmax−dmin) Δn) of the liquid crystal layer increases (Δn is the birefringence of the liquid crystal layer). Decrease in rate increases. Therefore, the relationship between the maximum film thickness (dmax) and the minimum film thickness (dmin) is
10 nm ≦ (dmax−dmin) Δn ≦ 60 nm
By optimizing the transmission rate, it is possible to minimize the decrease in transmittance.

  It is preferable that the transparent electrode formed on each of the pair of transparent electrode substrates is a common electrode that is not patterned. Since the transmissive region and the barrier light-shielding region are each formed of a translucent resin layer and a liquid crystal layer, fine patterning of the transparent electrode is not required. Accordingly, since the disconnection failure due to the transparent electrode pattern being linear, for example, does not occur, the manufacturing yield can be improved.

  Further, when the transparent electrode pattern is, for example, linear, when applied to a large parallax barrier element, a voltage drop due to wiring resistance occurs, and a display defect due to gradation occurs. In the case of a barrier element, since a common electrode that is not patterned is used, the voltage drop as described above does not occur. Therefore, a barrier display without gradation can be performed, and a good three-dimensional image can be displayed. .

  The stereoscopic video display apparatus of the present invention can also be configured to include the parallax barrier element of the present invention and a video display element having a left-eye pixel unit and a right-eye pixel unit. In the case where the image display element is a display element that is not self-luminous type, for example, a liquid crystal display element, it is desirable to further include a light source disposed farther from the observer than the parallax barrier element and the image display element. Examples of the light source include an area light type backlight in which a lamp such as a cold cathode fluorescent tube is disposed below the surface of the parallax barrier element and the image display element, and an edge light type backlight in which the lamp is disposed on the end surface of the light guide plate. It is done.

  The gap between the pair of transparent electrodes is divided into a region filled with a translucent resin having a substantially isotropic refractive index and a region filled with a liquid crystal material having refractive index anisotropy. When no voltage is applied to the parallax barrier element, the light beam from the light source is linearly polarized by the polarizing plate when entering the parallax barrier element having an optical shutter function for forming the parallax barrier. Even if the polarized light is incident on a region filled with a light-transmitting resin having a substantially isotropic refractive index, the polarized light is kept as it is and emitted from the parallax barrier element.

  On the other hand, in the region filled with the liquid crystal material having refractive index anisotropy, the polarization state changes according to the alignment state of the liquid crystal layer. Therefore, the polarization state can be separated according to the region divided by the above configuration. By disposing the polarizing plate so that the polarization direction of the emitted light in the transmissive region matches the transmission axis of the polarizing plate, the transmissive portion and the barrier light shielding portion can be formed. Furthermore, a stereoscopic image can be displayed by combining with a video display element having a left-eye pixel portion and a right-eye pixel portion.

  The liquid crystal layer is preferably displayed by switching between a three-dimensional image and a two-dimensional image by switching light shielding / transmission according to an electrical signal applied to the pair of transparent electrodes.

  When displaying a two-dimensional image by a parallax barrier element having an optical shutter function, the refractive index anisotropy of the liquid crystal layer can be eliminated by applying or not applying a common electrode. The linearly polarized light incident on the element is emitted from the parallax barrier element as it is without being affected by the refractive index anisotropy of the liquid crystal layer. That is, the polarized light emitted from the region filled with the liquid crystal material has the same polarization state as the polarized light emitted from the region filled with the translucent resin, so that the polarized light emitted from both regions is a parallax barrier element. It can permeate | transmit the polarizing plate arrange | positioned at the output side. Therefore, the parallax barrier disappears and a bright and easy-to-see two-dimensional image can be displayed.

  In this way, the barrier light-shielding region filled with the liquid crystal material is switched between light-shielding / transmission by the electrical signal applied to the transparent electrode, and thus the stereoscopic video display device switches between the three-dimensional image and the two-dimensional image. Can be displayed.

[Embodiment 1]
FIG. 1 is a cross-sectional view schematically showing a stereoscopic video display device (video display device) according to the present embodiment. Moreover, the principal part is shown in FIG. The stereoscopic image display apparatus according to the present embodiment is provided on a parallax barrier element (barrier element) 10 having an optical shutter function and on the back side of the parallax barrier element 10 (opposite side to the observer side, the same applies hereinafter). And a backlight (not shown) disposed on the back side of the image display element 20. The video display element 20 includes a pixel unit 101 (video display unit) that displays a right-eye image and a pixel unit 102 (video display unit) that displays a left-eye image. In the present embodiment, the parallax barrier element 10 is disposed on the front surface of the video display element 20, but is not particularly limited, and may be disposed on the rear surface of the video display element 20.

  The parallax barrier element 10 includes, for example, a pair of transparent electrode substrates 1 and 2 made of glass provided with a transparent electrode, and a pair of polarizing plates 3 and 4 provided outside the pair of transparent electrode substrates 1 and 2. Have. The pair of transparent electrode substrates 1 and 2 have alignment films (not shown) subjected to alignment treatment in a predetermined direction on the opposing surfaces. Hereinafter, the parallax barrier element 10 is also referred to as a liquid crystal panel. In the figure, A is the transmission axis of the upper polarizing plate 3, and B is the transmission axis of the lower polarizing plate 4.

  The liquid crystal panel 10 includes a barrier light-shielding region (light-shielding part) 111 that separates light from the pixel part 101 that displays a right-eye image and light from a pixel part 102 that displays a left-eye image, and pixels that display a right-eye image. A transmission region (transmission unit) 112 that transmits the light from the unit 101 and the light from the pixel unit 102 that displays the image for the left eye. A liquid crystal layer 11 is formed in the barrier light shielding region 111 in the gap between the pair of transparent electrode substrates 1 and 2.

  Further, in the transmission region 112 in the gap between the pair of transparent electrode substrates 1 and 2, a translucent resin layer 12 having a substantially isotropic refractive index is formed as a transmission layer.

  In other words, the parallax barrier element 10 includes a plurality of, here, two video display units (pixel unit 101 and pixel unit 102) for displaying an image, which are repeatedly arranged on a plane in a certain order (here, two). A light-shielding portion (barrier light-shielding region 111) that is disposed in front of the alternating video display elements (video display element 20) and controls on / off of light transmission of the image from each of the video display parts on a plane. And a transmission portion (transmission region 112) that constantly transmits the light, and transmits only light traveling in a specific direction from each of the video display portions, and does not transmit light traveling in other directions. The barrier element can change the observable position where the image can be seen for each video display unit.

  The parallax barrier element 10 generates a right-eye image and a left-eye image as described above, and enables a three-dimensional image display without using special glasses or the like. On the other hand, the image for the right eye and the image for the left eye can be replaced with the image for the right observer and the image for the left observer, respectively, and another person can observe each as a separate two-dimensional image. Similarly, the right-eye image and the left-eye image are replaced with the upper (or lower) observer image and the lower (or upper) observer image, respectively, and another person observes them as separate two-dimensional images. It can also be. Also, instead of two video display units (pixel unit 101 and pixel unit 102), three (respectively A, B, and C) are repeatedly arranged in a certain order, that is, A, B, C, A, B , C, A, B, C,..., Arranged in the order of right side observer image, middle side observer image, left side observer image, upper side observer image, middle side observer It is also possible to use an image for the lower side and an image for the lower observer. The same applies to four or more. In either case, the barrier element transmits only light traveling in a specific direction (for example, only the right observer image if there are three), and light traveling in the other direction (for example, if there are three, the remaining elements) By preventing the transmission of the middle-side observer image and the left-side observer image), the observable position where the image can be seen can be changed for each video display unit.

The translucent resin layer 12 is composed of at least two types of film thickness areas, for example, a high film thickness area (maximum thickness area) 112H and a low film thickness area (thin thickness area) 112L. The high-thickness region 112H has a function as a spacer for keeping the gap between the pair of transparent electrode substrates 1 and 2 constant. The gap between the low-thickness region 112L and the transparent electrode substrate 1 or 2 has a film thickness difference dmax. The liquid crystal is filled with a thickness of −dmin. dmax is the film thickness of the region 112H having a high film thickness, and dmin is the film thickness of the region 112L having a low film thickness. dmax is just the thickness in the region of the liquid crystal layer 11. By forming the liquid crystal layer in the gap as a cushion layer, it is possible to suppress external impact and generation of bubbles in a low temperature environment. Furthermore, the relationship between the thicknesses of the regions having different thicknesses is 10 nm ≦ (dmax−dmin) Δn ≦ 60 nm.
(Δn is the birefringence of the liquid crystal layer), so that the polarization of the liquid crystal layer in which the polarized light transmitted through the transmission part 112 is filled in the gap between the region 112L with a small film thickness and the transparent electrode substrates 1 and 2 (( Good display can be performed without being affected by the decrease in transmittance due to dmax−dmin) Δn). The derivation of the relational expression will be described in the following examples.

  The translucent resin layer used for the transmission part does not have the function of uniformly maintaining the gap of the liquid crystal layer of the parallax barrier element in addition to the above function, and the region with the maximum film thickness (film thickness = dmax) It can also be configured to be smaller than the film thickness of the liquid crystal layer.

  In the present embodiment, the liquid crystal panel 10 is disposed in front of the video display element 20. However, in a display device such as a liquid crystal display device using a backlight as a light source, in other words, in a display device other than a self-luminous display device such as an EL (electroluminescence) display device, the liquid crystal panel 10 and the video display element There is no problem even if the front-rear arrangement of 20 is reversed. For example, the image display element 20, the liquid crystal panel 10, and the backlight (light source) may be arranged in this order from the observer side.

  Next, the display principle of the stereoscopic video display apparatus according to the present embodiment will be described with reference to FIGS. 3 and 4.

  In the present embodiment, a case where the liquid crystal layer 11 has a parallel (homogeneous) alignment including a liquid crystal material having a positive dielectric anisotropy and has a retardation of λ / 2 when no voltage is applied will be described. λ is the wavelength of light passing through the liquid crystal layer 11. In the figure, X and Y are the vibration directions (polarization directions) of light after passing through the translucent resin layer 12 and the liquid crystal layer 11, respectively.

  In the present embodiment, the parallel alignment method of the liquid crystal layer 11 is adopted for convenience of explanation, but there is no particular limitation, and polarization of incident light such as a vertical alignment method and a TN (twisted nematic) alignment method is used. Any orientation method can be adopted as long as the state can be changed.

  Furthermore, in the parallax barrier element of the present invention, the liquid crystal layer may have a memory property. For example, when the liquid crystal layer 11 is formed from a ferroelectric liquid crystal material, it is only necessary to energize the liquid crystal panel 10 as a parallax barrier element only when switching between two dimensions (planar) / 3 dimensions (three-dimensional). Low power consumption is possible.

  FIG. 3 is a cross-sectional view showing the display principle of the three-dimensional image display by the stereoscopic video display apparatus according to the present embodiment. The display principle when no voltage is applied to the liquid crystal panel 10 functioning as a parallax barrier element, in other words, a three-dimensional image display will be described with reference to FIG.

  The transmission axis directions of the polarizing plates 3 and 4 are set substantially parallel to each other. The alignment direction of the liquid crystal layer 11 is desirably set to 45 ° with respect to the transmission axis direction of the polarizing plates 3 and 4. In the figure, the symbol represented by X or Y represents the direction of the polarization plane, and the symbols X and Y represent that the respective polarization planes are substantially orthogonal. That is, here, X is a direction parallel to the paper surface, and Y is a direction perpendicular to the paper surface.

  First, light transmitted through the liquid crystal layer 11 will be described. When the light linearly polarized by the lower polarizing plate 4 enters the liquid crystal layer 11, it becomes polarized light whose polarization direction is rotated by 90 ° by the retardation (λ / 2) of the liquid crystal layer 11. Since the transmission axis directions of the pair of polarizing plates 3 and 4 are set substantially parallel to each other, the linearly polarized light transmitted through the liquid crystal layer 11 cannot transmit through the upper polarizing plate 3. Therefore, the barrier light-shielding region 111 where the liquid crystal layer 11 is formed is darkly displayed, and a parallax barrier can be formed.

  Next, the light transmitted through the translucent resin layer 12 will be described separately for the region 112H having the maximum film thickness and the region 112L having a low film thickness. In the case of light transmitted through the region 112H having the maximum film thickness, when the light linearly polarized by the lower polarizing plate 4 enters the translucent resin layer 12, the translucent resin layer 12 exhibits refractive index anisotropy. Since there is almost no, it keeps the polarization state as it is and enters the upper polarizing plate 3 on the exit side.

On the other hand, in the case of light that passes through the other low thickness region 112L,
10 nm ≦ (dmax−dmin) Δn ≦ 60 nm
By setting to, the upper polarizing plate 3 is hardly affected by the retardation of the liquid crystal layer on the region 112L having a low film thickness, so that the polarization state is hardly changed like the region 112H having the maximum film thickness. (The relational expression will be described later).

  Since the transmission axis directions of the upper polarizing plate 3 and the lower polarizing plate 4 are set substantially parallel to each other, the light emitted from the translucent resin layer 12 passes through the upper polarizing plate 3. Thereby, the transmissive area | region 112 in which the translucent resin layer 12 is formed will be in a bright state, and the image for right eyes and the image for left eyes can each be displayed. Therefore, when no voltage is applied to the liquid crystal panel 10 that performs polarization separation, the barrier light-shielding region 111 forms a parallax barrier, so that a three-dimensional image can be displayed.

  FIG. 4 is a cross-sectional view showing the display principle of the two-dimensional image display by the stereoscopic video display device of the present embodiment. The display principle when a voltage is applied to the polarization separation liquid crystal panel 10, in other words, a two-dimensional video display will be described with reference to FIG.

  First, light transmitted through the liquid crystal layer 11 will be described. In the voltage application state, the liquid crystal molecules in the liquid crystal layer 11 rise in the inter-electrode direction, so that the linearly polarized light incident on the liquid crystal layer 11 is not affected by the liquid crystal layer 11 and remains in the polarization state as it is. Incident on the polarizing plate 3. Therefore, the linearly polarized light incident on the liquid crystal layer 11 is transmitted through the upper polarizing plate 3, so that the barrier light shielding region 111 where the liquid crystal layer 11 is formed is in a bright state.

  About the light which permeate | transmits the translucent resin layer 12, since it permeate | transmits the upper polarizing plate 3 similarly to the time of a three-dimensional image display, the permeation | transmission area | region 112 in which the translucent resin layer 12 is formed will be in a bright state. . Therefore, in the voltage application state of the liquid crystal panel 10 that functions as a parallax barrier, the parallax barrier is electrically extinguished, and the barrier light shielding region 111 in which the liquid crystal layer 11 is formed and the transmission in which the translucent resin layer 12 is formed. Since all the regions 112 are in a bright state, a bright two-dimensional image can be displayed.

[Embodiment 2]
In the first embodiment, a case where a pair of polarizing plates 3 and 4 are used has been described. However, a λ / 4 plate (quarter wavelength plate) or a λ / 2 plate (half wavelength) is used as necessary. A retardation plate such as a plate) and a polarizing plate may be used in combination. In this embodiment, a display principle of a stereoscopic video display device using a λ / 2 plate as a retardation plate will be described. Note that the liquid crystal layer 11 in the present embodiment is a parallel (homogeneous) liquid crystal layer including a liquid crystal material having a positive dielectric anisotropy, as in the first embodiment, and is λ when no voltage is applied. It has a retardation of / 2.

  FIG. 5 is a cross-sectional view showing the display principle of the three-dimensional image display by the stereoscopic video display device of the present embodiment. The display principle when no voltage is applied to the liquid crystal panel 10 functioning as a parallax barrier element, in other words, a three-dimensional image display will be described with reference to FIG.

  The stereoscopic image display apparatus according to the present embodiment includes a λ / 2 plate 5 disposed in a gap between the upper transparent electrode substrate 1 and the upper polarizing plate 3 facing the upper transparent electrode substrate 1. The transmission axis directions of the pair of polarizing plates 3 and 4 are set so as to be substantially orthogonal to each other. The alignment direction of the liquid crystal layer 11 is desirably set to 45 ° with respect to the transmission axis direction of the lower polarizing plate 4.

  First, light transmitted through the liquid crystal layer 11 will be described. When the light linearly polarized by the lower polarizing plate 4 enters the liquid crystal layer 11, it becomes polarized light whose polarization direction is rotated by 90 ° by the retardation (λ / 2) of the liquid crystal layer 11. The polarized light emitted from the liquid crystal layer 11 is rotated by −90 ° again by the λ / 2 plate 5 disposed on the emission side, and returned to the original polarization state. Since the transmission axis directions of the pair of polarizing plates 3 and 4 are set so as to be substantially orthogonal, the linearly polarized light that has passed through the liquid crystal layer 11 cannot pass through the upper polarizing plate 3. Therefore, the barrier light-shielding region 111 where the liquid crystal layer 11 is formed is darkly displayed, and a parallax barrier can be formed.

  Next, the light transmitted through the translucent resin layer 12 will be described by dividing it into the maximum film thickness region 112H and the other low film thickness region 112L.

When the light linearly polarized by the lower polarizing plate 4 enters the translucent resin layer 12, the translucent resin layer 12 has almost no refractive index anisotropy, and thus maintains the polarization state as it is. Then, the light enters the λ / 2 plate 5. On the other hand, in the case of light that passes through the other low thickness region 112L,
10 nm ≦ (dmax−dmin) Δn ≦ 60 nm
Since it is hardly affected by the retardation of the liquid crystal layer on 112L, it is incident on the λ / 2 plate 5 with almost no change in the polarization state as in the region of 112H having the maximum film thickness. (The relational expression will be described later). The polarized light is incident on the upper polarizing plate 3 with the polarization plane rotated by 90 ° according to the λ / 2 plate 5.

  That is, the polarized light is incident on the upper polarizing plate 3 with a polarization plane rotated by 90 ° with respect to the transmission axis direction of the lower polarizing plate 4. Since the transmission axis direction of the upper polarizing plate 3 is substantially orthogonal to the transmission axis direction of the lower polarizing plate 4, the polarized light incident on the upper polarizing plate 3 is transmitted through the upper polarizing plate 3. Thereby, the transmissive area | region 112 in which the translucent resin layer 12 is formed will be in a bright state, and the image for right eyes and the image for left eyes can each be displayed. Therefore, when no voltage is applied to the liquid crystal panel 10 that performs polarization separation, the barrier light-shielding region 111 forms a parallax barrier, so that a three-dimensional image can be displayed.

  FIG. 6 is a cross-sectional view illustrating the display principle of the two-dimensional image display by the stereoscopic video display apparatus according to the present embodiment. The display principle when a voltage is applied to the polarization separation liquid crystal panel 10, in other words, a two-dimensional image display will be described with reference to FIG.

  First, light transmitted through the liquid crystal layer 11 will be described. In the voltage application state, the liquid crystal molecules in the liquid crystal layer 11 rise in the direction between the electrodes, so that the linearly polarized light incident on the liquid crystal layer 11 is not affected by the liquid crystal layer 11 and remains in the polarization state as it is. / 2 The light enters the plate 5. The polarized light is incident on the upper polarizing plate 3 with the polarization plane rotated by 90 ° according to the λ / 2 plate 5. Since the transmission axis directions of the pair of polarizing plates 3 and 4 are set so as to be substantially orthogonal, the linearly polarized light transmitted through the liquid crystal layer 11 is transmitted through the upper polarizing plate 3. Therefore, the barrier light shielding region 111 where the liquid crystal layer 11 is formed is in a bright state.

  About the light which permeate | transmits the translucent resin layer 12, since it permeate | transmits the upper polarizing plate 3 similarly to the time of a three-dimensional image display, the permeation | transmission area | region 112 in which the translucent resin layer 12 is formed will be in a bright state. . Therefore, in the voltage application state of the liquid crystal panel 10 that functions as a parallax barrier, the parallax barrier is electrically extinguished, and the barrier light shielding region 111 in which the liquid crystal layer 11 is formed and the transmission in which the translucent resin layer 12 is formed. Since all the regions 112 are in a bright state, a bright two-dimensional image can be displayed.

  As shown in Embodiments 1 and 2, a parallax barrier can be formed by applying no voltage to the region (barrier light shielding region) 111 in which the liquid crystal layer 11 of the liquid crystal panel 10 is formed. Therefore, a three-dimensional image can be observed by forming the video display element 20 as a three-dimensional image of a right-eye image and a left-eye image and forming a parallax barrier on the liquid crystal panel 10. Further, when a two-dimensional image is displayed on the video display element 20, it is possible to display a two-dimensional image by applying a voltage to the liquid crystal panel 10 used as the parallax barrier element and extinguishing the parallax barrier. Therefore, according to the stereoscopic video display devices of Embodiments 1 and 2, switching between a two-dimensional image and a three-dimensional image can be easily performed.

  The liquid crystal panel 10 shown in the first and second embodiments is combined with a video display element 20 including a pixel unit 101 that displays a right-eye image and a pixel unit 102 that displays a left-eye image. A stereoscopic video display device that can be switched electrically is obtained. As the video display element 20, a flat panel display such as a liquid crystal display panel, an organic or inorganic EL display panel, a PDP (plasma display panel), a fluorescent display tube, or the like can be used. The pixel arrangement of the video display element 20 is not limited to the stripe arrangement, but may be a delta arrangement, a mosaic arrangement, a square arrangement, or the like. As the image display element 20, a black and white or full color display panel can be used.

  In the three-dimensional image display device described in Patent Document 2, since the PVA film 50 is formed on the entire surface of the transparent support plates 60 and 61 (solid), when the PVA film 50 is thermally contracted, the transparent support plate 60 and 61 contraction is likely to occur. However, in the parallax barrier element of the present invention, the translucent resin layer 12 can be formed in a stripe shape by using a stripe barrier pattern or the like. Therefore, even if the translucent resin layer 12 is thermally contracted, the influence on the substrates 1 and 2 due to the thermal contraction of the translucent resin layer 12 is greater than that in the case where the translucent resin layer 12 is solid. small.

[Embodiment 3]
An example of a method for manufacturing the polarization separation liquid crystal panel 10 used in the stereoscopic image display device of the present invention will be described. First, a transparent electrode (not shown) made of ITO (indium tin oxide) or the like is formed on the lower substrate 2. For convenience of explanation, the lower substrate 2 will be described as an example, but the upper substrate 1 can be manufactured in the same manner as the lower substrate 2.

  The transparent electrode may be patterned, but it is preferable in the manufacturing process to use a solid (unmatched) electrode that is not patterned. A generally available substrate with ITO may be used. For example, a negative resist type photosensitive acrylic resin material is applied as a translucent resin to the substrate 2 on which ITO is formed by a spin coating method or the like. In order to form at least two or more types of regions in the photosensitive acrylic resin material, a photomask is used so that different exposure amounts are given to the high-thickness region 112H and the low-thickness region 112L. What is necessary is just to perform exposure. By exposing the region 112L having a smaller film thickness to the region 112L having a lower film thickness by exposing an exposure amount smaller than that given to the region 112H having a higher film thickness, the region 112L has a smaller amount of exposure than the region 112H. Since the film thickness is increased, the region 112H having a high film thickness and the region 112L having a low film thickness can be easily formed.

For example, as a method of exposing different exposure amounts to the region 112H and the region 112L,
(1) A method of exposing a plurality of times using different photomasks in order to perform exposure with a predetermined exposure amount (2) A light can be diffracted into an opening region of a photomask corresponding to 112L which relatively reduces the exposure amount A method of forming a fine light-shielding pattern (a level that cannot be resolved) and providing a difference in relative exposure amount (3) A photomask opening area corresponding to 112L that has a relatively low exposure amount has a different transmittance. A method of forming a light-shielding material (halftone material) to give a difference in relative exposure amount, etc. can be raised.

  The photosensitive resin exposed at different exposure amounts as described above is developed with an aqueous NaOH solution, for example, and further subjected to a baking treatment, whereby the translucent resin layer 12 having at least two types of film thickness regions is obtained. Can be formed. Since the region 112H having a high film thickness of the translucent resin layer 12 also has a spacer function, it is not necessary to separately form or scatter the spacer, and the manufacturing process is simplified.

  After forming the translucent resin layer 12, an alignment film (not shown) made of, for example, polyamic acid is applied to the lower substrate 2 by a printing method and baked. Furthermore, the lower substrate 2 can be obtained by performing an alignment treatment by, for example, a rubbing method. If necessary, an insulating film may be formed in the gap between the alignment film and the transparent electrode.

  A peripheral sealing material is printed on one of the upper substrate 1 and the lower substrate 2 by, for example, a printing method, and preliminary baking is performed in order to remove a solvent component in the sealing material. After bonding the upper substrate 1 and the lower substrate 2, a liquid crystal material 11 is formed by injecting a liquid crystal material from an injection port formed in the peripheral sealing material and sealing the injection port. Note that the liquid crystal material may be injected by a dispenser method instead of the dip method. Specifically, a peripheral sealing material without an inlet is formed on one substrate, a liquid crystal material is dropped into the frame of the peripheral sealing pattern, and then both substrates 1 and 2 are bonded to form the liquid crystal layer 11. May be. The liquid crystal panel 10 can be obtained through the above steps.

  Since the liquid crystal panel 10 can form a parallax barrier pattern using photolithography generally used in the manufacturing process of a liquid crystal display device, the liquid crystal panel 10 is manufactured without changing the existing liquid crystal manufacturing process at all. be able to. Specifically, the translucent resin layer 12 can form a fine barrier pattern with high pattern dimensional accuracy by using general photolithography. Further, even when a fine parallax barrier is required, there is no need to pattern the transparent electrode, so that there is no failure in switching between light shielding / transmission due to disconnection of the transparent electrode.

  The parallax barrier pattern can be arbitrarily selected according to the pixel pattern of the video display element 20 such as a stripe barrier pattern, a matrix barrier pattern, and an oblique barrier pattern having a stepped opening. Furthermore, since the barrier pattern can be formed by a photolithography method, an arbitrary pattern shape such as a curved shape as well as a linear shape can be selected.

  In order to more specifically describe the parallax barrier element of the present invention, examples of the present invention will be described. The liquid crystal panel 10 as a parallax barrier element in this example was manufactured by the following process. First, a spacer negative resist solution (“JNPC-77” (trade name) manufactured by JSR Corporation) is applied to a spin coater on a substrate 2 made of glass with ITO (indium tin oxide) (not shown). And rotated for 1 minute at 2000 rpm. Pre-baking was performed at 120 ° C. for 10 minutes in a clean oven to remove the residual solvent in the spacer. Exposure was performed using a photomask that had been subjected to a halftone process so that a desired translucent resin pattern of the liquid crystal panel 10 was obtained. At this time, the region 112H having a high film thickness is exposed to ultraviolet rays under an exposure amount of 200 mJ, developed with a 2% aqueous solution of NaOH at 30 ° C. for 1 minute, washed with water, and then washed at 230 ° C. for 40 minutes in a clean oven. Firing was performed.

  Next, an alignment film made of polyamic acid was formed and baked in a clean oven at 250 ° C. for 30 minutes. The baked alignment film was subjected to an alignment treatment by rubbing so as to have a desired alignment direction, whereby a lower substrate 2 was obtained. The upper substrate 1 was obtained in the same manner as the lower substrate 2.

  A peripheral sealing material (“XN-21S” (trade name) manufactured by Mitsui Chemicals, Inc.) was formed on the upper substrate 1 using a screen plate in which a frame-like seal shape was patterned. In order to remove the residual solvent in the sealing material, it was heated in a clean oven at 100 ° C. for 30 minutes. The upper and lower substrates 1 and 2 were bonded and baked at 200 ° C. for 60 minutes.

  The liquid crystal layer 11 was formed in the parallax barrier region 111 by injecting a liquid crystal material into the gap between the bonded upper and lower substrates 1 and 2. By attaching a pair of polarizing plates 3 and 4 (“SEG1425DU” manufactured by Nitto Denko Corporation) to the upper and lower substrates 1 and 2, it was possible to obtain the polarization separation liquid crystal panel 10 of this example having an optical shutter function.

  Here, the result of optimizing the film thickness difference between the regions 112H and 112L having different film thicknesses formed in the translucent resin layer 12 from the viewpoint of the transmittance of the transmission region 112L having the low film thickness of the parallax barrier element is shown in FIG. Shown in In addition, the impact from the outside and the reliability results in a low temperature environment are also shown in FIG.

  In this evaluation, a parallel (homogeneous) alignment liquid crystal layer 11 including a liquid crystal material having a positive dielectric anisotropy was used. The liquid crystal layer 11 has a retardation of λ / 2 when no voltage is applied (λ is the wavelength of transmitted light). Further, the transmission axis directions of the polarizing plates 3 and 4 are set substantially parallel to each other. Further, the alignment direction of the liquid crystal layer 11 was set to 45 ° with respect to the transmission axis direction of the polarizing plates 3 and 4. The transmittance was measured using TOPCON BM5 (color luminance meter), and the transmittance when an AIR reference was used is shown in FIG.

From FIG. 7, it can be seen that in the region where the range of (dmax−dmin) Δn is 0 to 60 nm, the transmittance change of the transmission region 112L is small and hardly changes. However, when the ratio exceeds 60 nm, the transmittance tends to be extremely reduced, so that the transmittance is reduced when the three-dimensional image is displayed, and the luminance becomes dark. Therefore, from the viewpoint of transmittance (luminance),
0 nm ≦ (dmax−dmin) Δn ≦ 60 nm
It is desirable to satisfy the relationship.

Furthermore, it can be seen from FIG. 8 that when dmax−dmin = 0, that is, dmax = dmin, it is particularly vulnerable to bubble defects due to external impact during low temperature storage. Except for special mobile phone applications, the low-temperature storage compensation temperature of -25 ° C for mid-sized and larger notebook personal computers and monitors
10 nm ≦ (dmax−dmin) Δn
By satisfying the above, it is possible to prevent the generation of bubbles against low temperature storage and external impact, and to ensure reliability.

Therefore, when the relationship between dmax and dmin is optimized from the above evaluation, from the viewpoint of transmittance and reliability,
10 nm ≦ (dmax−dmin) Δn ≦ 60 nm
It is further desirable to satisfy this relationship.

Also from the viewpoint of transmittance and reliability,
20 nm ≦ (dmax−dmin) Δn ≦ 60 nm
It is further desirable to satisfy this relationship.

  Next, in addition to the parallel alignment shown in the first and second embodiments, a vertical separation and a TN alignment type polarization separation liquid crystal panel 10 were respectively formed. Here, (dmax−dmin) Δn = 20 nm. Using these liquid crystal panels 10, the orientation method of the liquid crystal layer 11, the positive and negative dielectric anisotropy of the liquid crystal layer, the arrangement of the pair of polarizing plates in the transmission axis direction, the presence of the λ / 2 plate 5, and three-dimensional image display Is the contrast between the liquid crystal layer 11 (barrier light shielding region) and the translucent resin layer 12 (that is, the luminance of the translucent resin layer 12 / the luminance of the liquid crystal layer 11 (luminance ratio). )). The results are shown in Table 1.

  When the λ / 2 plate 5 is used, the λ / 2 plate 5 may be disposed in either the gap between the upper substrate 1 and the polarizing plate 3 or the gap between the lower substrate 2 and the polarizing plate 4. . As the λ / 2 plate 5, a two-dimensional retardation plate “NRF” made of polycarbonate was used. This λ / 2 plate has a retardation of 260 nm.

  The contrast measurement between the translucent resin layer 12 and the liquid crystal layer 11 (barrier light shielding part) was performed using a TOPCON BM5 (color luminance meter). The parallel alignment and TN alignment were measured with no voltage applied, and the vertical alignment was measured by applying a 10 V / 200 Hz rectangular wave.

表１に示すように、すべての条件で良好なコントラストを示し、良好なパララックスバリア性能を示していることが分かる。平行配向および垂直配向では共に、一対の偏光板の透過軸方向が互いに直交するように配置し、かつλ／２板を用いる場合、非常に高いコントラストを得ることができる。すなわち、良好な３次元画像を得ることができる。一方、一対の偏光板の透過軸方向が互いに平行に配置されている場合には、若干低めのコントラストを示す。しかし、十分なパララックスバリア性能を示しており、λ／２板５を用いる必要がないので、製造コストの抑制が可能である。

As shown in Table 1, it can be seen that good contrast was exhibited under all conditions, and good parallax barrier performance was exhibited. In both the parallel alignment and the vertical alignment, when the transmission axis directions of the pair of polarizing plates are arranged so as to be orthogonal to each other and a λ / 2 plate is used, a very high contrast can be obtained. That is, a good three-dimensional image can be obtained. On the other hand, when the transmission axis directions of the pair of polarizing plates are arranged parallel to each other, a slightly lower contrast is shown. However, sufficient parallax barrier performance is shown, and it is not necessary to use the λ / 2 plate 5, so that the manufacturing cost can be suppressed.

  Further, when a voltage was applied to the parallel and TN-oriented parallax barrier elements, the barrier light-shielding region 111 in which the liquid crystal layer 11 was formed was in a bright state, and a bright and good two-dimensional image display could be confirmed. Note that since the transmittance of the liquid crystal layer 11 changes in accordance with the drive voltage, a brighter two-dimensional image display can be performed by setting the drive voltage high.

  In the case of the Barrax barrier element using the vertical alignment, the barrier light-shielding region 111 in which the liquid crystal layer 11 is formed is in a bright state by setting the parallax barrier element to a voltage-free state, and a bright and good two-dimensional image. The display could be confirmed.

  In the case of parallel orientation and TN orientation, 3D image display is performed when no voltage is applied. Therefore, power consumption can be reduced by applying it to electronic equipment that mainly performs 3D image display rather than 2D image display. It is. On the other hand, in the case of the vertical orientation, two-dimensional image display is performed when no voltage is applied. Therefore, application to an electronic device that mainly performs two-dimensional image display rather than three-dimensional image display reduces power consumption. Is possible. Therefore, according to the purpose of the electronic device to be used, specifically, by selecting the orientation mode appropriately depending on whether the 3D image display is mainly performed or the 2D image display is mainly performed, it is possible to reduce the consumption. Electricity becomes possible.

  The parallax barrier element of the present invention includes a transmissive portion filled with a translucent resin having a substantially refractive index between a pair of transparent electrode substrates, and a barrier light-shielding portion filled with a liquid crystal material. By providing a parallax barrier, a three-dimensional image can be displayed. Further, the entire region of the parallax barrier element can be brightly displayed by electrically switching the liquid crystal layer. For example, bright display can be achieved by applying a voltage in the case of parallel alignment and TN alignment, and by applying no voltage in the case of vertical alignment. Therefore, a bright two-dimensional image can be displayed. Furthermore, the parallax barrier element of the present invention is a liquid crystal panel having a very simple configuration and easy to manufacture.

  The translucent resin layer formed between the pair of transparent electrode substrates included in the parallax barrier element of the present invention is preferably composed of at least two types of thickness regions, and the highest thickness region. Therefore, since it has the function of a spacer that keeps the gap between the pair of transparent electrode substrates constant, it is possible to easily ensure the reliability in a low temperature environment.

  The translucent resin layer formed between the pair of transparent electrode substrates included in the liquid crystal panel as the parallax barrier element of the present invention uses photolithography that is frequently used in the manufacturing process of a normal liquid crystal display device as it is. Can be formed. Therefore, it is not necessary to introduce any new process, and it is possible to manufacture a parallax barrier element with a very simple process and high dimensional accuracy of the barrier pattern.

  According to the liquid crystal panel as the parallax barrier element of the present invention, it is not particularly necessary to pattern the transparent electrode of the transparent electrode substrate, so that even when a fine barrier pattern is formed, disconnection failure does not occur. Therefore, the manufacturing yield can be improved, and the voltage drop due to the wiring resistance of the transparent electrode in a large application such as a notebook personal computer, a monitor, or a television is very small, so that a large stereoscopic display device without gradation is provided. I can do it.

  According to the liquid crystal panel as the parallax barrier element of the present invention, the alignment method of the liquid crystal layer is set to parallel or TN alignment, so that three-dimensional image display is performed in the absence of voltage application and two-dimensional in the voltage application state. Image display can be performed. Furthermore, by using the λ / 2 plate in combination, it is possible to obtain a further excellent barrier performance and obtain a very good three-dimensional image.

  According to the liquid crystal panel as the parallax barrier element of the present invention, the alignment method of the liquid crystal layer is set to the vertical alignment so that two-dimensional image display is performed in the absence of voltage application and three-dimensional image display in the voltage application state. It can be performed. Furthermore, by using the λ / 2 plate in combination, it is possible to obtain a further excellent barrier performance and obtain a very good three-dimensional image.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. Embodiments are also included in the technical scope of the present invention.

  It is possible to view a three-dimensional image without using special glasses, and it can also be applied to a use for displaying a two-dimensional image.

1 is a cross-sectional view illustrating an outline of a stereoscopic video display device according to a first embodiment. 1 is a cross-sectional view illustrating an outline of a stereoscopic video display device according to a first embodiment. 3 is a cross-sectional view illustrating a display principle of three-dimensional image display by the stereoscopic video display apparatus according to Embodiment 1. FIG. 3 is a cross-sectional view illustrating a display principle of two-dimensional image display by the stereoscopic video display device according to Embodiment 1. FIG. 6 is a cross-sectional view illustrating a display principle of a three-dimensional image display by the stereoscopic video display apparatus according to Embodiment 2. FIG. 6 is a cross-sectional view illustrating a display principle of two-dimensional image display by the stereoscopic video display device according to Embodiment 2. FIG. It is a figure which shows the transmittance | permeability of the transmissive area | region of the stereoscopic video display apparatus of Example 1. It is a figure which shows the reliability evaluation result of the three-dimensional video display apparatus of Example 1. FIG. 10 is a cross-sectional view illustrating a display principle of a three-dimensional image display by a three-dimensional image display device described in Patent Document 2. FIG. 10 is a cross-sectional view illustrating a display principle of a two-dimensional image display by a three-dimensional image display device described in Patent Document 2. FIG.

Explanation of symbols

1 Upper substrate 2 Lower substrate 3 Upper polarizing plate 4 Lower polarizing plate 5 λ / 2 plate 10 Parallax barrier element (barrier element)
11 Liquid crystal layer 12 Translucent resin layer (transmission layer)
20 Video display element 31 Upper substrate 32 Lower substrate 33 Liquid crystal layer 34 Polarizing plate 50 PVA film 51 Polarizing region 52 Non-polarizing region 60 Support 101 Right-eye pixel unit (video display unit)
102 Left-eye pixel unit (video display unit)
111 Barrier light shielding area (light shielding part)
112 Transmission area (transmission part)
112H High-thickness region in the transmission region (maximum thickness region)
112L Low-thickness region in the transmission region (thin region)

Claims (7)

A plurality of video display units for displaying an image are arranged on the front or back of a video display element repeatedly arranged in a certain order on a plane,
On the plane, a light-shielding unit that controls on / off of light transmission of the image from each video display unit, and a transmission unit that constantly transmits the light are alternately and repeatedly provided.
In the barrier element that changes the observable position where the image can be seen for each video display unit by transmitting only light traveling in a specific direction from each video display unit and not transmitting light traveling in other directions,
A liquid crystal layer is formed on the light shielding portion, and a transmissive layer made of a translucent resin material having a refractive index substantially isotropic is formed on the transmissive portion. . The liquid crystal layer and the transmission layer are formed in a gap between a pair of transparent electrode substrates,
  The barrier element according to claim 1, wherein the transparent electrodes respectively formed on the pair of transparent electrode substrates are flush common electrodes. The transmissive layer is formed of at least two types of regions including a maximum thickness region having the same thickness as the liquid crystal layer and a thin region having a thickness smaller than the maximum thickness region. Item 3. The barrier element according to Item 1 or 2. 3. The barrier according to claim 1, wherein the video display unit includes two types, and images displayed by the video display units are a right-eye image and a left-eye image in a three-dimensional display of the same image. element. The barrier element according to claim 1, wherein the images displayed by the video display units are independent images. When the thickness of the maximum thickness region is dmax, the thickness of the thin region is dmin, and the birefringence of the liquid crystal layer is Δn,
  The retardation of the liquid crystal layer is
  10 nm ≦ (dmax−dmin) Δn ≦ 60 nm
The barrier element according to claim 3, wherein: Two types of video display units, which are a left-eye pixel unit and a right-eye pixel unit, respectively, and a barrier element are provided, and a three-dimensional image and a two-dimensional image are switched and displayed by switching light shielding / transmission by the barrier element. In a stereoscopic image display device,
  A barrier element according to claim 1 or 2,
  A three-dimensional image display device, wherein a three-dimensional image and a two-dimensional image are switched and displayed by switching light shielding / transmission in a liquid crystal layer of the barrier element in accordance with an applied electric signal.

Images