JP2004512564A - Autostereoscopic display - Google Patents

Abstract

An autostereoscopic display apparatus includes an image forming apparatus and a substrate having alternating strips, wherein strips having first optical properties are separated by strips having different optical properties. The substrate may consist of alternating strips of polarizing film separated by transparent, non-polarizing strips. Instead, the substrate consists of first staggered strips that delay the linearly polarized light component by half a wavelength, and they are separated by a second staggered strip that delays the linearly polarized light component by one wavelength. It may be. Another removable, polarizing substrate may be removably placed in front of the substrate containing these alternate strips. If the movable polarizing substrate is placed in a direction in front of the strips, the observer will see an autostereoscopic image, and if the polarizing substrate is removed, a 2D image will be visible.

Description

[0001]
This application claims priority to earlier provisional application No. 60 / 104,142 filed on Oct. 14, 1998 and No. 60 / 150,789 filed on Aug. 26, 1999.
[0002]
(Background of the Invention)
U.S. Pat. No. 4,717,949 (Eichen Raob) discloses an autostereoscopic display that uses a flat screen and displays a plurality of narrow vertical light emitting lines thereon. In front of the screen is an image forming device, such as a liquid crystal display, including a row and column of pixels, which forms an image by changing the transmissivity of individual pixels located across its surface. The screen and light valve are arranged so that the observer sees these emission lines through one set of pixels with the left eye and the same line through another set of pixels with the right eye.
[0003]
(Summary of the Invention)
The present invention provides an autostereoscopic display device. Generally, the device is an imaging device that includes display pixels arranged in rows and columns; a first substrate that includes alternating strips, and has a first optical property that these alternate strips include. A substrate wherein the strips are separated by strips having different second optical properties; and a polarizing substrate, wherein each of the first substrate and the polarizing substrate is independently optically positioned before or after the image forming apparatus. I have.
[0004]
According to various preferred embodiments, the device comprises a first polarizing substrate optically positioned before or after the imaging device and having alternating strips of polarizing film separated by transparent, non-polarizing strips. And a second polarizing substrate optically disposed before or after the image forming apparatus. According to another preferred embodiment, the apparatus includes an optical delay substrate including a first alternating strip that delays a component of the passing linearly polarized light by half a wavelength, the first strip comprising a component of the passing linearly polarized light. Are delayed by a second alternating strip. For these embodiments, these alternating strips are preferably arranged vertically. The image forming device may be a transparent, electronically addressed liquid crystal display, the display comprising an addressable liquid crystal layer in an array of individual pixels, the device further comprising a backlight source. Alternatively, the imaging device may be an emissive, addressable display with display pixels arranged in rows and columns.
[0005]
For an embodiment using a polarizing substrate with alternating strips of polarizing film, the device includes a second, non-imaging LCD without pixel structure, wherein the LC panel is the liquid crystal of the second LCD. It may be possible to switch between autostereoscopic imaging and 2D viewing by applying and removing voltages to the layers.
[0006]
According to various embodiments, a movable, second polarizing substrate may be removably placed in front of the substrate containing these alternating strips. If the movable polarizing substrate is placed in a direction in front of the strips, the observer will see an autostereoscopic image, and if the polarizing substrate is removed, a 2D image will be visible.
[0007]
(Detailed description of preferred embodiments)
FIG. 1 shows the front side (closer to the viewer) of an electronically addressed liquid crystal display 15 consisting of two glasses 17, 18 together with a liquid crystal layer 16 addressable to an array of individual pixels arranged in rows and columns. An analyzer comprising a first polarizing sheet 24 in any of the following: a weak diffuser or diffusing surface in front of this polarizing sheet 24; a polarizing film sandwiched between transparent areas in the form of narrow slits 33 which do not polarize the light passing therethrough. A second polarizing sheet 27 (as shown in the front view of FIG. 2) consisting of vertical strips 32; a third glass sheet 36; the molecular orientation can be changed by applying a voltage over the entire surface, without a pixel structure The autostereoscopic display 10 has a second liquid crystal layer 38; a fourth glass sheet 37; a third polarizer 20; and a backlight I that emits normally white scattered light. For purposes of illustration, it is assumed that the polarization directions of all three polarizing sheets are the same, as indicated by arrows 5 on each sheet of FIG. 1 and in the polarizing strip of FIG. However, other directions can be used, and sheets that polarize light in different directions can be used. For example, most LCDs use a polarization direction of 45 degrees from vertical and horizontal. For the purposes of this example, it is also assumed that in the off state (no voltage applied), the second liquid crystal layer 38 (without a pixel structure) does not change the polarization direction of light passing through it. However, as will be apparent from the description of the operation of this device below, this may also differ depending on the polarization direction of the polarizer.
[0008]
When no voltage is applied to the second liquid crystal layer 38, light passes through it and the polarizing strip 32 of the second polarizing sheet 27, and then simply passes through the first liquid crystal layer 16, whereas individual pixels The applied voltage changes the polarization of the light to varying degrees so that the light passing through the different pixels is free to pass through the first (pre) polarizing sheet 24, and thereby is extinguished to some extent; As in the normal case of a liquid crystal display, an image is formed that is visible to the observer 13 located on the opposite side of the sheet 24.
[0009]
When a voltage is applied to the second liquid crystal layer 38, the polarization direction of the light passing therethrough changes by 90 degrees and is blocked by the polarizing strip 32 of the second polarizing layer 27. However, it passes freely through the transparent slits 33 between the polarizing strips 32. Next, the polarization direction of the light passing through the strip 32 is changed to various degrees by the pixels in the first liquid crystal layer 1.6, and the light passing through the different pixels is changed to various degrees by the first polarizing sheet 24. Erased, thereby forming an image visible from the other side of the sheet.
[0010]
The interval between the transparent slits 33 of the second polarizing sheet 27 is selected according to the equation: p = 2 / ((I / w)-(1 / e)), where p is the pitch of the slits and w is the horizontal of the first LC layer 16. The pixel pitch in the direction, and e is the average separation distance between the eyes of the observer 13. Typically, a value of 63 mm is used for e, which is also used for adults. The width of the slit 33 will typically be half the width of the polarizing strip 32. Because this seems to give the best visual result.
[0011]
An observer 13 looking at the display 10 with this "on" second liquid crystal layer 38 sees light passing through the transparent slit 33, and if the polarizing strip 32 is in this second layer 38, the dark area between them is wide. The observer then sees the liquid crystal display illuminated by the light lines behind the pixels of the first LC layer 16. Given the formula for slit pitch shown above, an "observation zone" is created in which the observer can observe the even number of first liquid crystal layers 16 according to the principles outlined in U.S. Pat. No. 4,717,949. Alternatively, light lines aligned behind the odd pixel columns are visible and the entire disclosure of that patent is incorporated herein by reference. If the left-eye image of the stereo pair is displayed in odd columns of pixels and the right-eye image is displayed in even columns, or vice versa, the observer may see that his or her left eye is behind a column of pixels displaying this left-eye image. U.S. Pat. No. 4,717,949 is again whenever the right eye is in the viewing area where the line is visible and the right eye is simultaneously located in the viewing area where the light line is visible behind the row of pixels displaying this right eye image. You will see a stereoscopic image according to the principles described in.
[0012]
Thus, by applying a voltage to or removing the voltage from the second LC layer 38, the observer can see both eyes an autostereoscopic image where every other row of pixels of the first LC layer 16 is visible, It is possible to switch between normal 2D viewing where all pixels are visible.
[0013]
In the 3D mode, the operation of the first LC layer 16 must be inverted from that in the 2D mode. For example, if applying no voltage to a pixel in 2D mode would show that pixel as a bright point, applying the maximum voltage would show it as a black point and somewhere in between would show it as a gray point. . In the 3D mode, no voltage applied represents it as a black point, while voltage applied represents it as a bright point, and again the intermediate voltage represents it as a gray point. This reversal of operation must be taken into account by the hardware or software controlling the pixels of the first LC layer 16 to ensure that the correct image is displayed, rather than a negative image, in each mode.
[0014]
It is possible to replace the second liquid crystal layer 38 with its own pixel row and column individually addressed. Each pixel will either pass light without changing its polarization direction (no voltage applied) or change the polarization direction by 90 degrees (voltage applied). Applying voltages to different groups of pixels in the second liquid crystal layer 38 to create a window in which light lines for 3D viewing surrounded by uniformly illuminated 2D regions (no light lines) or vice versa Can be done.
[0015]
Modifications and additions of this basic design are possible. For example, neutral, non-polarizing filter strips may be placed in gaps 33 between polarizing strips 32 to equalize the amount of light passing through these strips and gaps per unit area to increase illumination uniformity in 2D mode. It is possible. These filters will need to block only about 10% to 20% of the light passing through them, depending on the polarizing material used for the strips 32. These filters may be strips of some neutral gray transparent material located within gaps 33 between the polarizing strips, or may be made by exposing a thin strip of photographic emulsion layer on the surface of the glass substrate on which the polarizing strips will be applied. Good.
[0016]
It is also possible to color the gaps 33 between the polarizing strips 32 to achieve this reduction in transmission. This has been demonstrated to effectively reduce the transmission to match the transmission between alternating strips of polarized and unpolarized light.
[0017]
Another variation may use a depolarizing strip in combination with a continuous sheet polarizer. Instead of using a gap between the polarizing strips, a continuous polarizing sheet with narrow parallel lines of depolarizing material may be used where the slits would otherwise be located. These strips of depolarizing material should be on the side of the polarizer facing the liquid crystal layer 38 of the second liquid crystal panel.
[0018]
There are many ways to make a polarizing sheet that includes a non-polarizing slit 33 and an alternating polarizing strip 32. These methods all start with a continuous sheet of polarizing material on a substrate, such as glass, and either remove the polarizing material in the area of the slit 33 or remove the polarizing properties of this material in these areas of the slit 33. These experimentally demonstrated methods are chemical bleaching, photo bleaching and chemical etching of a continuous polarizing sheet using an etching mask to create regions of the polarizing strip 32.
[0019]
Polarizing sheets 20, 24, 27 and strips 32 may function as conventional polarizers, i.e., they may absorb components of light waves that are oscillating in unwanted directions. However, in some cases, it is preferable to use a new type of polarizing film that reflects light components oscillating in unwanted directions. This reflected light will re-enter the backlight 11 where it will diffuse and some will reappear with the correct orientation polarization component. Thus, the overall brightness of the display is increased. This type of reflective polarizing film is manufactured by 3M (St. Paul, MN, USA) and is called a double brightness enhancement film. It is developed for the purpose of "recycling" light polarized in unwanted directions as described above, thereby increasing the brightness of the liquid crystal display.
[0020]
An alternative configuration is shown in FIG. This configuration has the disadvantage that the polarizing strip 32 must be placed further away from the LC pixel layer 16, thereby pushing the viewing distance further away from the imaging LCD. This makes it impractical to implement on many LCDs. Nevertheless, this arrangement has the advantage that there is no need to flip the image between 2D and 3D modes, which may make it desirable in some situations.
[0021]
FIG. 3 shows a polarizer 24 on the front side of the LCD 15, typically as in an off-the-shelf LCD arrangement. As before, the imaging LCD 15 includes two sheets of glass 17, 18 with a layer 16 of liquid crystal material between them. A third glass sheet 36 is located behind the rear polarizer 22 of the imaging LCD 15. A second liquid crystal layer 38 without pixel structure is placed between this glass sheet 36 and a fourth glass sheet 36 located behind it. Behind the fourth glass sheet 37 is a vertical strip 32 of polarizing film sandwiched by a transparent region 33 that does not polarize the passing light (as shown in the front view of FIG. 4). A backlight that emits normally white scattered light is located behind these other elements. For purposes of illustration, it is assumed that the polarization directions of all three polarizing sheets are the same, as indicated by arrow 5 on each sheet of FIG. 3 and in polarizing strip 32 of FIG. However, other directions can be used, and sheets that polarize light in different directions can be used. It is also assumed that in the off state (no voltage applied), the second liquid crystal layer 38 (without a pixel structure) does not change the polarization direction of light passing through it.
[0022]
When no voltage is applied to the second liquid crystal layer 38, light passing through the polarizing strips 32 and the gaps 33 between them passes through it and the polarizing sheet 22 behind the imaging LCD 15, and then the first liquid crystal layer 16. In contrast to the simple passing, the voltage applied to each pixel changes the polarization direction to various degrees, so that light passing through different pixels can pass freely through the front polarizing sheet 24 or the front polarizing sheet 24, so that the observer 13 located on the opposite side of the sheet 24 sees it, as in the usual case of a liquid crystal display.
[0023]
When a voltage is applied to the second liquid crystal layer 38, the polarization direction of light passing therethrough changes by 90 degrees. Thus, light that has passed through the strip 32 is blocked by the polarizing layer 22 behind the imaging LCD 15. However, light that has passed through the gap 33 between the polarizing strips 32 still passes freely through the polarizer 22 after the imaging LCD 15. Next, the polarization direction of the light passing through the gap 33 is changed to various degrees by the pixels in the image forming liquid crystal layer 16, and the light passing through the different pixels is erased to various degrees by the pre-polarizing sheet 24, so that Form an image visible from the other side of the sheet.
[0024]
The spacing of the transparent strips 32 of polarizing material is again selected according to the formula p = 2 / ((I / w)-(1 / e)), where p is the pitch of the transparent slit and w is the horizontal of the first LC layer. The pixel pitch in the direction, and e is the average separation distance between the eyes of the observer 13. Typically, a value of 63 mm is used for e.
[0025]
An observer looking at the display with the second liquid crystal layer 38 in this active ("on") state will see the light passing through the transparent slit 3, but if there is a polarizing strip 32 there will be a dark strip between them. The observer sees the liquid crystal display illuminated by the light lines behind the pixels of the first LC layer. Given the formula for slit pitch shown above, an "observation zone" is created in which the observer can observe the even number of first liquid crystal layers 16 according to the principles outlined in U.S. Pat. No. 4,717,949. Alternatively, an optical line aligned behind the odd-numbered pixel column can be seen. If the left-eye image of the stereo pair is displayed in odd columns of pixels and the right-eye image is displayed in even columns, or vice versa, the observer may see that his or her left eye is behind a column of pixels displaying this left-eye image. A stereoscopic image will be visible whenever the right eye is in the viewing area where the line is visible and the right eye is simultaneously located in the viewing area where the light line is visible behind the pixel array displaying this right eye image.
[0026]
Thus, by applying a voltage to or removing the voltage from the second LC layer 38, the observer can see both eyes an autostereoscopic image where every other row of pixels of the first LC layer 16 is visible, It is possible to switch between normal 2D viewing where all pixels are visible.
[0027]
As described above, in this embodiment, when changing from the 2D mode to the 3D mode, there is no need to turn the image between positive and negative. Regardless of the state of the second LC layer 38, white pixels appear white and black pixels appear black.
[0028]
It is possible to replace the second liquid crystal layer 38 with its own pixel row and column individually addressed. Each pixel will either pass light without changing its polarization direction (no voltage applied) or change the polarization direction by 90 degrees (voltage applied). Ferroelectric liquid crystal materials are ideally suited for this purpose. Applying voltages to different groups of pixels in the second liquid crystal layer 38 to create a window in which light lines for 3D viewing surrounded by uniformly illuminated 2D regions (no light lines) or vice versa Can be done.
[0029]
Modifications and additions of this basic design are possible. For example, neutral, non-polarizing filter strips may be placed in gaps 33 between polarizing strips 32 to equalize the amount of light passing through these strips and gaps per unit area to increase illumination uniformity in 2D mode. It is possible. These filters will need to block only about 10% to 20% of the light passing through them, depending on the polarizing material used for the strips 32. Again, the gap 33 may be colored.
[0030]
Another variation may use a depolarizing strip in combination with a continuous sheet polarizer. Instead of using a gap between the polarizing strips, a continuous polarizing sheet with narrow parallel lines of depolarizing material may be used on the side facing the imaging LCD 15 and the viewer 13 or else where the slits are located. These strips of depolarizing material would have to be placed on the side of the polarizer facing the liquid crystal layer of the second liquid crystal panel.
[0031]
According to another embodiment, the polarizer 27 with the slit and the second polarization rotating liquid crystal layer 38 are arranged on the front side (the side facing the observer 13) of the image forming LCD 15, and the polarizing strip 32 is arranged on the front side of the image forming LCD 15. It can also be placed on the side facing the observer. A rear polarizer 22 is provided behind the glass sheet 18 of the image forming LCD 15. One such configuration is shown in FIG. Here, the front polarizer 24 of the image forming LCD 15 has been removed and replaced by a polarizing strip of polarizer 27. A second LC layer 38 is in front of the polarizing strip 32, and the continuous polarizing sheet 24 is in front of the second LC glass 36 (the side facing the viewer). In this case, the formula for the spacing of the slits 33 between the polarizing strips 32 is P = 2 / (I / w + 1 / e), where P is the slit pitch, w is the pixel pitch, and e is the observer Eye separation, which averages about 63 mm for adults. The polarization directions of these polarizing strips are chosen such that when the pixels of the imaging LCD 15 are in the white ("on") state, light coming from the imaging LCD 15 is free to pass through them. The polarization direction of the pre-polarizer 24 is selected such that when the second LC layer is inactive, it also passes light coming from these polarizing strips and also passes light coming from white (“on”) pixels seen through these slits. I have. Thus, the light coming from all the pixels of the image forming LCD 15 is visible to the observer, and the polarizing strip 32 is almost invisible.
[0032]
When the second LC layer 38 is activated, it changes the direction of polarization of the light at the viewer's side from the previous direction to a direction of 90 degrees, thereby blocking any light passing through the polarizing strip 32, but Light from the slit 33 between 32 is still allowed to pass. Under this condition, an observer looking at the display sees the pixels of the imaging LCD 15 through the transparent slit 33, but there is a dark strip between the polarizing strips 32, if any. Given the slit pitch formula given above, an "observation zone" is created in which the observer is familiar with the art, and the book of stereoscopic computer graphics and other true 3D techniques (see Aligned behind even or odd pixel columns of imaging liquid crystal layer 16 according to the general principles outlined in Chapter 3, Section 3.6 of David McArista, edited by Princeton University Press, ISBN 0-691-08741-5). You can see the slit. The associated geometry is similar to illuminating the LCD with a slit located behind it. If the left eye image of the stereo pair is displayed in odd columns of pixels and the right eye image is displayed in even columns, or vice versa, the observer will see his or her left eye through the slit in the pixel column displaying this left eye image. Whenever you are in the viewing area and your right eye is simultaneously located in the viewing area that is visible behind the slit in the row of pixels displaying this right-eye image, you will again see the stereoscopic image, according to generally known principles. Would.
[0033]
In this configuration, the forefront polarizer 24, the one closest to the observer 13, acts as an analyzer to prevent unwanted polarized light from exiting the system, so that the image is visible.
[0034]
Thus, by applying a voltage to or removing the voltage from the second LC layer 38, the observer can see both eyes an autostereoscopic image where every other row of pixels of the first LC layer 16 is visible, It is possible to switch between normal 2D viewing where all pixels are visible.
[0035]
When in the 3D mode, the operation of the first LC layer 16 must be reversed again from when it was in the 2D mode. For example, if applying no voltage to a pixel in the 2D mode would make that pixel appear as a bright point, applying the maximum voltage would make it appear as a black point and somewhere in between would appear as a gray point. In the 3D mode, the state without voltage appears as a black point when viewed through the slit, while the voltage applied state manifests it as a bright point, and again the intermediate voltage manifests it as a gray point. This reversal of operation must be taken into account again by the hardware or software controlling the pixels of the imaging LCD 15 to ensure that the correct image is displayed in each mode, rather than the negative image.
[0036]
Another configuration with the second LC layer 38 and the strip polarizer 32 in front of the imaging LCD 15 is shown in FIG. Here, the continuous front polarizer 24 of the image forming LCD 15 is held. An additional glass sheet 36, 37 and a second LC layer 38 are placed in front of this polarizer and the polarizing strip substrate 23 is placed in front of the second LC glass 36 (closest to the viewer 13). In this case, the formula for the slit spacing is P = 2 / (1 / w + 1 / e), where P is the slit pitch, w is the pixel pitch, and e is the separation of the observer's eyes, It averages about 63 mm for adults. The polarization directions of these polarizing strips 32 are chosen such that light coming from the front polarizer 24 of the imaging LCD 15 is free to pass through them when the second LC layer 38 is inactive (ie, "off"). is there. So, in this state, the observer will see all pixels with both eyes and will hardly see the strip 32.
[0037]
When the second LC layer 38 is activated, it changes the polarization direction of light passing through it to a direction at 90 degrees from its previous direction. This light is then blocked by the polarizing strips 32 and the observer sees only the light from the imaging LCD 15 that passes through the slits 33 between the polarizing strips 32. As before, because of the slit spacing, the observer's left eye sees odd columns of pixels through the slit, and the right eye sees even columns of pixels, so that the left eye screen of the stereo pair is in these odd columns and the right eye screen Are displayed in even columns, a 3D image will be recognized.
[0038]
With this configuration, there is no need to invert the image on the image forming LCD between the 2D mode and the 3D mode. Regardless of the state of the second LC layer, white pixels remain white and black pixels remain black.
[0039]
Any of these "before the second LC" configurations of FIGS. 5 through 8 can employ the design variations described for the "after the second LC" configurations of FIGS. For example, the second LCD 35 may take the form of a monochrome LCD with independently addressable pixels in rows and columns or even some other configuration. By activating pixels in one area and not activating others, a 3D window with a 2D background or vice versa can be created. Within the gap between the slits 33 it is also possible to place a second row of strips made of a non-polarized neutral filter material. These filter strips can provide approximately equal amounts of light per unit area exiting the polarizing strip and the slit. These polarizing strips may also be replaced by a continuous polarizer, on the side facing the LC layer in the second liquid crystal panel, with a line of depolarizing material co-located with the slit.
[0040]
5-8 with a slit in front of the imaging LCD 15 can be used for other types of imaging displays other than LCDs. In other words, the image forming apparatus does not need to be transmissive and may be releasable. The main requirement is that the display pixels are well-defined and arranged in a linear matrix. Emissive displays 40 meeting these criteria include plasma displays, electroluminescent (EI) displays, field emission displays (FED), and some conventional CRTs. When used with such an emissive display 40, the continuous polarizer 24 must be located on one side of the LC layer 38 and glass assembly, and the strip polarizer 32 and slit 33 on the other side. As shown in FIG. 10, the continuous polarizer 24 may be at the front and the strip polarizer 32 may be at the back, or vice versa, as shown in FIG.
[0041]
According to another embodiment, the present invention provides an autostereoscopic display comprising a delay filmstrip and a removable polarizer. The autostereoscopic display of this configuration is very lightweight, has a small cross section, and includes relatively low cost autostereoscopic optics, making it particularly applicable to laptop computers and other portable equipment.
[0042]
FIG. 1 uses a typical liquid crystal display 15 as its image source, the liquid crystal display being the far side (the side facing the backlight 11 opposite to the observer 13) and the front side (ie, the viewing side). 2 shows a cross-sectional view of the stereoscopic display 10 having another polarizing sheet 24 acting as an analyzer (on the side closest to the person 13). In addition to the polarizing sheets 20, 24, the liquid crystal display 15 includes two transparent substrates 17, 18, such as glass, with a liquid crystal layer 16 sandwiched therebetween. This liquid crystal layer 16 is addressable to an array of individual pixels arranged in rows and columns to create an image. Optional elements in the form of a diffuser 42 may be included in front of the pre-polarizer sheet 24. The diffuser 42 will ideally blur the pixels of the LCD just to the point where the black border between them disappears, to avoid moire effects in stereoscopic 3D mode.
[0043]
The delay sheet or film 50 includes alternating vertical strips, and as shown in the front view of FIG. 12, a set of strips 51 delays one component of linearly polarized light by half a wave and a second alternating strip. The set 52 delays one component of linearly polarized light by one wave. Therefore, the delay sheet 50 rotates the polarization direction of the light. This delay sheet or film is in front of the pre-polarizer 24 and optional diffuser 42, as shown in FIG.
[0044]
A third removable polarizing sheet 60, preferably approximately the same size and shape as the liquid crystal display 15, may be placed by an observer in front of other elements, or may be removed from the display by the observer. For the following discussion, the polarization directions of the two polarizing sheets 20, 24 are the same, as indicated by the arrows 5 on each sheet in FIG. The same is true for this removable sheet when placed in the proper orientation in front of the display, parallel to the long side of the display. However, other directions can be used, and sheets that polarize in different directions can be used. For the sake of this discussion, the thin strips 52 of the delay film 17 of FIG. 12 change the polarization direction of light passing through them by 360 degrees, thereby resulting in a one-wave portion that, when light enters, results in polarization in the same direction. It is also assumed that the thick strips 51 are half-wave portions that change the polarization direction of light passing through them by 90 degrees. Note that the direction of the fast axis of this retardation film must be at a 45 degree angle to the polarization direction of the polarizing sheet 24 from which light exits to cause this.
[0045]
This strip of delay film will typically be made starting with a single wave film and then etching away a wide area to create a half wave strip 51, as shown in plan cross-section in FIG. An additional layer 55 may be added in the form of a laminate having substantially the same refractive index as that of but having no retardation characteristics. This layer will prevent diffraction and scattering from steep slopes and comers between the single wave and half wave strips. Ideally, an anti-reflective coating is also provided on the front side of the laminate 55 to reduce the reflection of ambient light from the display.
[0046]
In the absence of the removable polarizing sheet 60, light simply passes through the retardation film 50 and reaches the viewer's eyes 13. The polarization direction of this light does not affect the visibility to the eyes, so that the observer sees all the pixels with each eye as usual. However, when the removable polarizing sheet 60 is in place, it will block the light exiting the wide strip because it is rotated by 90 degrees. As a result, observer 13 appears to be looking through a slit barrier placed in front of the LCD.
[0047]
The spacing of the one-wave strips 52 on the delay film is preferably selected according to the formula p = 2 / ((I / w)-(I / e)), where p is the pitch of the slit and w is the LC layer. And e is the average separation between the observer's eyes. Typically, a value of 63 mm is used for e 1, but a smaller value is preferred if the device is to be used for viewing by children. The width of half wave strip 51 will typically be twice the width of one wave strip 52. Since this generally gives the best visual result.
[0048]
An observer looking at the display with the removable polarizer 60 in place will see the light passing through the one-wave slit 52, and if there is a half-wave strip 51 there will be a large dark area between them. Thus, the observer sees the liquid crystal display through an alternating barrier of opaque lines and narrow transparent slits. For the slit pitch formulas listed above, an "observation zone" is created, into which the observer is well-known in the art and, among other things, stereoscopic computer graphics and other true 3D In accordance with the general principles outlined in Chapter 3, Section 3.6 of the book of Technology (edited by David McArista, Princeton University Press, ISBN 0-691-08741-5), even or odd pixel columns of the first liquid crystal layer 16 A light line aligned behind is visible. If the left-eye image of the stereo pair is displayed in odd columns of pixels and the right-eye image is displayed in even columns, or vice versa, the observer may see that the left-eye pixel column displaying this left-eye image is behind the slit. Whenever the right eye is in the observation area visible to the eye and the pixel array displaying this right eye image is simultaneously located in the observation area visible behind the slit, again according to the principles described in the book referenced above, You will see a stereo image.
[0049]
Thus, by placing or removing the removable polarizer 60 in place, the observer may have an autostereoscopic image in which every other row of LC layer 16 pixels can be seen in both eyes, and all LC layers 16 in both eyes. It is possible to switch between normal 2D viewing where the pixels are visible.
[0050]
According to an alternative embodiment, an emissive display is used instead of an LCD, in which case a polarizing sheet is placed in front, followed by a diffuser 15 and a retardation film 17 in front of this polarizer.
[0051]
In each case, a convenient coupling mechanism for the removable polarizer 60 is to hinge the polarizer 60 to the display 10 (as shown in FIG. 22), for example, at a hinge 90 at the top of the display 10. This allows the viewer to flip the polarizer 60 between a position in front of the display 10 and a position where the polarizer 60 is not in front of the display 10. The advantage of this configuration is that the polarizer moves easily between the two positions, but remains permanently attached to the display device so that it is not lost or damaged. An alternative is to make this removable polarizing sheet 60 very flexible and wrap it around the rollers 91 so that it is rolled down and back again in front of the LCD 15 (as shown in FIG. 23). Yet another alternative is to attach the removable polarizer to a rigid frame 92 that removably snaps or clips into a plastic case 93 surrounding the LCD (as shown in FIG. 24) and uses this when not in use. Store in display or laptop case pocket.
[0052]
Besides using for video or computer driven LCD displays, the system is also effective for certain handheld calculators, personal secretaries such as those marketed under the Palm Pilot trademark, and other display devices that present virtually graphics. Can be used.
[0053]
An alternative embodiment of the autostereoscopic display is shown in FIGS. In this embodiment, the thin portions 57 have no delay films on them, so that the light does not change polarization direction at all as it passes through them. As with the configuration described above, light has a similar polarization direction as it exits these narrow sections as it enters. Thick strips 51 are half-wave portions that change the polarization direction of light passing through them by 90 degrees. These strips are attached to a substrate 59, ideally made of glass, which gives the structure rigidity. Under certain circumstances, this glass substrate may be, for example, the front glass of the LCD display 15 when there is no diffuser 42. This configuration may be made by adhering a continuous layer of a half-wave retarder film to one side of the substrate, and then etching away the narrow portions to expose the substrate. As before, a layer 55 of index matched laminate may be placed over the delay strip to fill the gap between them to prevent scattering and reflected light from the sides and edges of these strips. . Once again, to enter the 3D mode, the user places the polarizing sheet 60 in front of the display in such a way that it blocks light exiting the half-wave portion 51 but allows light exiting the narrow portion 57 to pass. If the polarizing sheet 60 is not in place, the observer will see the unobstructed light from all parts.
[0054]
FIG. 16 shows yet another embodiment of an autostereoscopic display with a delay filmstrip. This embodiment uses electro-optical means to achieve a 2D / 3D function. As in the embodiment of FIGS. 11-14, a wide strip of delay film 51 is sandwiched between thin strips 61 and is in front of the front polarizer. These narrow sections 61 have no delay film or have a thickness sufficient to rotate the direction of light passing through them by a multiple of 180 degrees. So the polarization direction of the light does not change at all after passing through this narrow part. The thick strips 51 are thick enough to rotate the direction of light passing through them by 90 degrees, where N is an odd integer. These strips are attached to a substrate 63, ideally made of glass, which gives the structure rigidity. This arrangement may be made by gluing a continuous layer of delay film to one side of substrate 63 and then etching away narrow portions 61. As with the configurations described above, to prevent scattering and reflected light from the sides and edges of these strips, a layer 55 of index matched laminate is placed over the delay strip to fill the gaps between them. Is also good.
[0055]
Imaging LCDs are usually designed so that the front and rear polarizers pass light polarized 45 degrees clockwise or counterclockwise with respect to the vertical. So, for example, if the light exiting the front polarizer 24 is polarized clockwise at 45 degrees to the normal, this light will pass through the narrow portion 61 of the film laminate 55 and then travel relative to the normal. It will remain polarized 45 degrees clockwise. As it passes through the thick portion 51 of the retardation film, its polarization direction is rotated by 90 degrees, so it will now be 45 degrees counter-clockwise perpendicular.
[0056]
A liquid crystal plate 15 without a polarizer on the back may be placed in front of the retardation film strips 51, 61 and their laminate 55, if any. The front polarizer 24 of the LCD is placed with its polarization direction vertical or horizontal so that when the LC panel is off, half of the light from the delay film 51 and the narrow portion 61 between them. Of the light passes through the polarizer 24. For the purpose of this discussion, it is assumed that the polarization direction of this pre-polarizer 24 is vertical. Thus, when the LC panel is off, light from both retardation filmstrips and the gap between them passes through the polarizer 24 in front of the LC panel 15 and all pixels of the LCD are clearly visible in both eyes. Looks even. When the LC panel 15 is turned on, it rotates the polarization direction of light passing through it counterclockwise by 45 degrees, so that the light coming from the delay film is now turned 90 degrees from vertical, and this LC panel Blocked by polarizer 24. Light from the narrow area is now oriented vertically, parallel to the polarization direction of this pre-polarizer. So it passes freely. The observer then sees the pixels of the LCD 15 only through these small parts, and if the left-eye image and the right-eye image are displayed using alternating rows of elements on this LCD, the 3D image will be displayed for the reasons previously described. You will see
[0057]
With this configuration, when switching between the 2D mode and the 3D mode, there is no need to change the image to negative on this LCD.
[0058]
Again, this strip of delay film is usually a one-wave film, with a wide portion etched away to create a half-wave strip, as previously described for the embodiment shown in plan cross-section in FIG. As such, additional layers may be added in the form of a laminate 55 having approximately the same refractive index as this retardation fill, but having no retardation properties. This layer will prevent diffraction and scattering from steep slopes and comers between the single wave and half wave strips. Ideally, the laminate also has an anti-reflective coating on the front side to reduce the reflection of ambient light from the display.
[0059]
The spacing of one wave strip on the delay film is selected according to the formula p = 2 / ((I / w)-(Ie)), where p is the pitch of the slit and w is the horizontal of this LC layer. The pixel pitch in the direction, and e is the average separation between the observer's eyes. Typically, a value of 63 mm is used for e 1, but if the device is to be used by a child, typically a smaller value will be used. The width of this half wave strip will typically be twice the width of a single wave strip. Since this generally gives the best visual result.
[0060]
Again, it is possible to use an emissive display instead of an LCD if the polarizing sheet is placed in front of the emissive display and then a diffuser and a delay film follow this polarizer.
[0061]
In general, in all cases where a delay film is involved, there is no built-in diffusion layer on the exposed surface, since such a diffusion layer can scatter light and cause ghosting. It is preferred to place the pre-polarizer on the LCD. If using an LCD in which such a diffusion layer is on the front polarizer, it is preferable to first adhere a smooth sheet material to all of this to disable the diffusion layer. Standard anti-reflective sheets, such as those made by OCLI, which have an adhesive layer on one side to facilitate adhesion, serve this purpose. However, they may have birefringent properties and be able to depolarize light passing through this polarizer if they are not oriented in one direction. This direction is usually the same as one of the sides of the original ready-made sheet, parallel to the sides of the LCD.
[0062]
Another embodiment of a 2D / 3D autostereoscopic display is shown in FIGS. 17 and 18, which involves a sheet of polarizing strip 71 on the front side (the side facing the viewer) of the imaging LCD 15. Here, the pre-polarizer of the image forming LCD is removed and replaced with the polarizing strip 71. In this case, the formula for the slit spacing between these polarizing strips is P = 2 / (I / w + 1 / e), where P is the slit pitch, w is the pixel pitch, and e is the observer's Eye separation, which averages about 63 mm for adults. The linear polarization directions of these polarizing strips 71 are typically chosen such that light coming from the imaging LCD 15 is free to pass through it when no output is applied to the imaging LCD 15 (this is a natural white color). This is typically referred to as LCDs manufactured today).
[0063]
The polarization direction of the strip 71 is also ideally at a 45 degree angle as indicated by the arrow 5 '. This direction is typical for very many LCDs. A second polarizing sheet 18 is provided for the observer. The sheet is separate or removable from the LCD assembly so that the viewer can put it in place and turn it if necessary. Placing this separate sheet 60 in front of the LCD such that its polarization direction is parallel to the polarization direction of the LCD strips 71 allows light to pass freely through these strips and polarizers. . The light coming from all the pixels on the imaging LCD is then visible to the observer and the polarizing strip is almost invisible.
[0064]
By holding a separate polarizing sheet 60 and flipping it around a horizontal line passing through its center and parallel to the long sides, the observer will see that its polarization direction is perpendicular to the polarization direction of the polarizing strip. Can be placed in the direction. This is shown in FIG. Thus, a separate polarizer 60 in turn blocks all light passing through the polarizing strip 71, thus allowing a viewer to see the pixels of the imaging LCD 15 only through the gap between the polarizing strips. Given the formula of slit pitch shown above, an "observation area" is created in which the observer is placed in front of the even or odd pixel columns of the imaging liquid crystal layer according to the general principles known in the art. You can see the slits that are aligned. If the left-eye image of the stereo pair is displayed in odd columns of pixels and the right-eye image is displayed in even columns, or vice versa, the observer may see that their left eye is displaying these left-eye images in these slits. Whenever the right eye is in the viewing area visible through the slit and its right eye is simultaneously located in the viewing area visible behind these slits, the right eye follows the general principle known in the art. , You will see a stereoscopic image.
[0065]
Thus, by flipping the separate polarizer 60, the observer sees every other row of 15 pixels of the imaging LCD with both eyes and sees all the pixels of this imaging LCD with both eyes. It is possible to switch between normal 2D observation.
[0066]
In the 3D mode, the operation of the image forming LCD must be inverted again from when it is in 2D. For example, if applying no voltage to a pixel in the 2D mode would make that pixel appear as a bright point, applying the maximum voltage would make it appear as a black point and somewhere in between would appear as a gray point. In the 3D mode, the state without voltage appears as a black point when viewed through the slit, while the voltage applied state manifests it as a bright point, and again the intermediate voltage manifests it as a gray point. This reversal of operation must be taken into account again by the hardware or software controlling the pixels of the imaging LCD to ensure that the correct image is displayed in each mode, rather than the negative image.
[0067]
Another possible but not convenient configuration is to allow a gap between the strip polarizer and the front of the imaging LCD. For example, the strip polarizer may be made on a rigid substrate spaced a small amount (typically 0.15 mm or less) from the front glass of the LCD. These separate polarizers slide down between the imaging LCD and the substrate on which the polarizing strip is mounted. Again, by placing it in one orientation with its polarization direction parallel to that of the polarizing strip, a 2D image with maximum resolution can be seen. By sliding it in with its polarization direction opposite to that of the polarizing strip, a 3D image can be seen.
[0068]
Another embodiment involves a removable toppling polarizer and a polarizing strip on the back side (away from the viewer) of the imaging LCD. This configuration is shown in FIGS. In this embodiment, the polarizer is removed and replaced with a sheet 70 of polarizing strips 71 after the image forming LCD. In this case, the formula for the slit spacing between these polarizing strips is P = 2 / (I / w-1 / e), where P is the slit pitch, w is the pixel pitch, and e is the observation pitch. Of the eyes of a subject, which averages about 63 mm for adults. The linear polarization directions of these polarizing strips 71 are typically chosen such that light exiting the polarizing strip when the imaging LCD is not powered is free to pass through the imaging LCD and the front polarizer 81. (This is called the natural white configuration and is typical of LCDs manufactured today).
[0069]
The polarization direction of the strip 71 is also ideally at a 45 degree angle as indicated by the arrow 5 '. A second polarizing sheet 60 is provided for the observer. This sheet is separate from the LCD assembly so that the viewer can put it in place and turn it if necessary. This sheet will also have linear polarization in the direction of 45 degrees on the sides. By placing the separate sheet 60 between the backlight 11 and the polarizing strip 71 of the LCD in front of the LCD in such an orientation that its polarization direction is parallel to the polarization direction of the LCD strip, light is emitted from these LCDs. It allows free passage through the strip and the polarizer. The light coming from all the pixels on the imaging LCD is then visible to the observer and the polarizing strip is almost invisible.
[0070]
By removing the polarizing sheet 60 and flipping it around a horizontal line passing through its center and parallel to the long side, the observer moves it between the backlight 11 and the polarizing strip 71, this time It can be placed in a direction whose polarization direction is perpendicular to the polarization direction of the polarizing strip. Thus, the polarizing strip 71 now blocks all light passing through the removable polarizer 60, but this figure is free to pass through the gap between the strips. The observer then sees the line of light behind every other pixel in this image formation. Given the formula of slit pitch shown above, an "observation area" is created in which an observer may have an even number or number of imaging liquid crystal layers in accordance with the principles outlined in U.S. Pat. No. 4,717,949. The slits aligned after the odd pixel columns are visible and the disclosure of that patent is incorporated herein by reference. If the left-eye image of the stereo pair is displayed in odd columns of pixels and the right-eye image is displayed in even columns, or vice versa, the observer may see that their left eye is displaying these left-eye images in these slits. Again, whenever the right eye is in the viewing area visible before these slits and the right eye is in the viewing area visible in front of these slits. According to the principles described in US Pat. No. 949, a stereoscopic image will be visible.
[0071]
In the 3D mode, the operation of the image forming LCD must be inverted again from when it is in 2D. For example, if applying no voltage to a pixel in the 2D mode would make that pixel appear as a bright point, applying the maximum voltage would make it appear as a black point and somewhere in between would appear as a gray point. In the 3D mode, the state without voltage appears as a black point when viewed through the slit, while the voltage applied state manifests it as a bright point, and again the intermediate voltage manifests it as a gray point. This reversal of operation must be taken into account again by the hardware or software controlling the pixels of the imaging LCD to ensure that the correct image is displayed in each mode, rather than the negative image.
[0072]
Another possible but not convenient configuration is to allow a gap between the strip polarizer 71 and the rear of the imaging LCD 15. For example, the strip polarizer 71 may be made on a rigid substrate spaced a small amount (typically 0.15 mm or less) from the rear glass 18 of the LCD. This separate polarizer 60 slides down between the imaging LCD and the substrate 70 on which the polarizing strip 71 is mounted. Again, by placing it in one orientation with its polarization direction parallel to that of the polarizing strip, a 2D image with maximum resolution can be seen. By sliding it in with its polarization direction opposite to that of the polarizing strip, a 3D image can be seen.
[0073]
The following describes a holographic diffuser device suitable for reducing and, in some cases, eliminating the appearance of moiré patterns as commonly encountered in many conventional 3D display systems. These embodiments may be implemented using strips of delay films or polarizing films before or after the above-described displays, as well as existing 3D displays such as those provided by Dimension Technology, Inc. (DTI, Rochester, NY, USA). It is applicable to various systems involving strips. Generally, the first and simplest device uses a polarizing strip and a transparent slit in front of the display, with a system such as described above, or with a strip of delay film before the display. Or the system with an opaque parallax barrier slit mask in front of the LCD. The second is a variant that can be used in systems that use a line of light after an LCD made by any one of a number of different means, including polarizing strips, strips of retardation films, and opaque parallax barrier slit masks.
[0074]
In some cases, including a diffuser, especially for the embodiments described above using a substrate with a polarizing strip at the front of the display, or for embodiments using an optical delay substrate at the front of the display It may be desirable. Diffusers designed for use in front strip devices work by blurring the pixels seen behind them until the gap between them disappears. Ideally, this diffuser should distribute the light as uniformly as possible within the blurred pixel images, and should blur these images as clearly as possible. A perfectly sharp image with perfectly uniform variance and no dark gaps between pixels will result in complete removal of moiré lines.
[0075]
The closest approach to this ideal diffuse pattern is to spread the light only horizontally and commonly referred to in the industry as a "top hat distribution pattern", where light coming from any single point spreads over sharp angles. And is provided by a diffuser in which the light spreads evenly over that angle, such a diffuser can be easily made using holographic or diffraction grating techniques, but the diffusion angle required is very small, One encounters a problem related to the fact that it is typically between I and 2 degrees, which requires that the holographic pattern or diffractive structure be quite large, and in fact can be as large as a pixel. Such a structure does not uniformly blur light from individual pixels, even if the overall pattern is uniform. Becomes a result produce "flash" like effect and undesirable scattered light image, it produces a ghost.
[0076]
Starting with a one-way diffuser that scatters light at a large angle in only one direction (eg, 10 to 20 degrees), the direction is set to an angle that is close to perpendicular but slightly inclined about an axis perpendicular to the diffuser. This problem can be avoided by having the largest component of the vector point along this vertical axis, while the smaller component of the scatter vector points along the horizontal axis. Experiments performed with a diffuser that scatters light in a single direction over about +/- 20 degrees have shown that a tilt angle of 10 degrees from vertical is sufficient to substantially eliminate Moire patterns. In this way, the light is spread in the horizontal direction by an appropriate amount. Because of this large angle of diffusion, the structures on the diffuser will be small and will be oriented more or less horizontally. Thus, a uniform and precisely controlled scattering pattern can be achieved.
[0077]
In practical devices, these pixels are diffused so that they overlap slightly in the vertical direction, but this is not a problem because the amount of overlap is so small as to be invisible.
[0078]
Ideally, such a diffuser should be located between the LCD and the preceding slit forming structure, and as close as possible to this slit structure.
[0079]
If the light lines are located behind the imaging LCD, a diffuser in the form of a strip, as described in US patent application Ser. No. 09 / 950,440, may be necessary and the disclosure of that application is incorporated by reference. Incorporated here. In this device, the diffuser must take the form of a flat substrate with alternating strips of transparent areas and strips that diffuse the light passing through. The diffusion strip layer must be located near a plane in front of the LCD pixels and must be aligned with the LCD light lines and pixel columns.
[0080]
When manufacturing these slits, one encounters the same problem with small diffusion angles and the resulting structure size. These diffractive structures must be so large that only a few fit within each strip. This means that the diffusion pattern from each strip cannot be accurately formed and also may result in unwanted orders of diffraction that direct some light to the wrong viewing area and thus cause ghosting.
[0081]
The solution to this problem is to diffuse the light again in one direction at a large angle, this direction being tilted a few degrees from vertical, and the exact angle starting into a grid or holographic pattern depending on the width and diffusion angle of the pixel boundaries It is. The grating or holographic pattern is ideally made in a thin layer, such as an epoxy or thin plastic, which can be etched and adhered to a rigid substrate. A thin vertical strip is then etched into this layer and the precisely spaced strips are etched away, as shown in U.S. Ser. No. 09 / 950,440, except that the diffusion angle is large and inclined at an angle from vertical. It is made by leaving a certain striped diffuser pattern.
[0082]
In either case (either a polarizing or delay strip before the LCD or a light line behind the LCD), a lenticular lens array (of many lenses per pixel) with a very fine lens pitch can be holographically or grating. Can be used instead of diffuser. Such lens arrays are commonly used as one-way diffusers for precisely controlling light in projection screens and other applications. This lenticular (cylindrical) lens is oriented with a slight vertical tilt from horizontal, which will slightly tilt the diffusion direction from vertical.
[0083]
25 and 26 show another embodiment of the present invention. This autostereoscopic display 10 has a polarizing sheet 20 on the far side (the side facing the backlight 11 away from the observer 13) and another polarizer acting on the front side (the side closest to the observer 13). An image forming LCD 15 having a polarizing sheet 24 is used. In addition to these polarizing sheets, the liquid crystal display includes two glasses 17, 18 having a liquid crystal layer 16 addressable to an array of individual pixels arranged in rows and columns to create an image. In the embodiment shown, a diffuser 42 is located in front of the front polarizer 24. The diffuser 42 will ideally blur the pixels of the LCD 15 just to the point where the black border between them is no longer visible to the observer to avoid the moire effects often encountered in autostereoscopic 3D mode. The diffuser 42 is a single diffuser having a relatively large diffusion angle in a direction slightly inclined (eg, 5 to 10 degrees) from vertical so that a small and precisely controlled amount of diffusion occurs in the horizontal direction. It may have a shape.
[0084]
A second LCD 35 without a polarizer is placed in front of the imaging LCD 15. The LCD 15 has electrodes 101 placed in a vertical strip pattern adjacent to its LC layer 38, as best seen in FIG. Upon actuation of these electrodes 101, these LC molecules are rotated, or otherwise redirected or affected, so that the polarization direction of light passing through these strips 101 is ideally 90 degrees or multiples thereof. Rotate. The liquid crystal material of layer 38 is typically a ferroelectric material or other LC material that has the property of rotating the molecules when a voltage is applied and keeping these molecules in the rotated direction when the voltage is removed. Should be material. Thus, the second LCD 35 is left in this state if the LC layer 38 under the electrode strip 101 is in its "active" (polarized light rotation) state during assembly and remains permanently in this state without any output. You may. If necessary, use this display 10 whenever and when this display is on, to ensure that the LC molecules remain in the correct orientation while using this display Periodically, a voltage can be again applied to this second LCD layer 38 for a short period of time.
[0085]
A third removable polarizing substrate 60, approximately the same size and shape as these liquid crystal displays, may be placed or removed by an observer in front of other elements. The polarization direction of the removable polarizer 60 is generally the same as the polarization direction of the polarizer 24 in front of the imaging LCD 15 when the removable polarizer 60 is in its proper orientation in front of the display 10. Would.
[0086]
When there is no removable polarizing substrate 60, the light simply passes through the second LCD 35 and reaches the observer's eyes 13. The polarization direction of this light does not affect the visibility to the eyes, so that the observer sees all the pixels of the image forming LCD 15 with each eye as usual. However, when the removable polarizing substrate 60 is in place, it blocks the polarization direction of the light exiting the wide electrode strip 101 because it has been rotated by 90 degrees, but the narrow strip 102 between the electrodes 101 The light that exits is allowed to pass. As a result, the observer appears to be looking through a slit barrier placed in front of the LCD.
[0087]
The spacing of the strips 102 between the electrodes 101 on the second LCD 35 is selected according to the formula p = 2 / ((I / w)-(I / e)), where p is the pitch of the slit and w is the electrical The horizontal pixel pitch of the LC layer in the addressed liquid crystal display 15, and e is the average separation between the observer's eyes. As in the previous example, a typical value of 63 mm is used for e based on the average separation of the adult eyes, but if the device is specifically designed for children to see, a smaller value should be used. Would. The width of electrode 101 will typically be twice the width of strip 102.
[0088]
An observer looking at the display with the removable polarizer 60 in place will see the light passing through the narrow slit 102 and if the polarization direction changes, there will be a large dark area between them. Thus, the observer sees the liquid crystal display through an alternating barrier of opaque lines and narrow transparent slits. Given the slit pitch formula given above, an "observation area" is created in which the observer follows the even or odd pixel columns of the first liquid crystal layer 16 according to the general principles discussed above. The up light line is visible. If the left-eye image of the stereo pair is displayed in odd columns of pixels and the right-eye image is displayed in even columns, or vice versa, the observer may see that his or her left eye is behind a column of pixels displaying this left-eye image. A stereoscopic image will be visible whenever the right eye is in the viewing area where the line is visible and the right eye is simultaneously located in the viewing area where the light line is visible behind the row of pixels displaying this right eye image.
[0089]
Thus, by placing the removable polarizer 60 in place or removing it, the observer can see both eyes with autostereoscopic imaging where every other row of pixels in the first LC layer 16 can be seen in both eyes, and in both eyes. It is possible to switch between normal 2D viewing where all pixels are visible. This removable polarizer 60 may have the shape described with reference to FIG. 22, FIG. 23 or FIG.
[0090]
If a polarizing sheet is placed in front and the diffuser and the second LCD and the removable polarizer are placed in front of this polarizing sheet, it is also possible to use emissive displays instead of transmissive imaging LCDs.
[0091]
The polarizing sheets 20, 24 and the strips 102 may function as conventional polarizers, that is, they may absorb components of the light wave that are oscillating in unwanted directions. However, at least in the case of the last polarizer, it is preferable to use a new type of polarizing film that reflects light components vibrating in unwanted directions. This reflected light will re-enter the backlight 11 where it will diffuse and some will reappear with the correct orientation polarization component. Thus, the overall brightness of the display is increased. This type of reflective polarizing film is manufactured by 3M (St. Paul, MN, USA) and is called a double brightness enhancement film. It is developed for the purpose of "recycling" light polarized in unwanted directions as described above, thereby increasing the brightness of the liquid crystal display.
[0092]
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that various changes may be made and elements may be substituted with equivalents without departing from the scope of the invention. right. In addition, many modifications may be made to adapt a particular situation of material to the teachings of the invention without departing from the scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode intended for implementing the invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims. .
[Brief description of the drawings]
FIG.
FIG. 2 is a plan view of the autostereoscopic display according to the first embodiment.
FIG. 2
FIG. 2 is a rear view of a polarizer with a slit used in the display of FIG. 1.
FIG. 3
FIG. 5 is a plan view of an autostereoscopic display according to a second embodiment.
FIG. 4
FIG. 4 is a rear view of a polarizer with a slit used in the display of FIG. 3.
FIG. 5
FIG. 9 is a plan view of an autostereoscopic display according to a third embodiment.
FIG. 6
FIG. 6 is a rear view of a polarizer with a slit used in the display of FIG. 5.
FIG. 7
FIG. 9 shows a plan view of an autostereoscopic display according to a fourth embodiment.
FIG. 8
It is a rear view of the polarizer by the slit used for the display of FIG.
FIG. 9
It is a top view of an autostereoscopic display by a 5th example.
FIG. 10
It is a top view of an autostereoscopic display by a 6th example.
FIG. 11
It is a top view of an autostereoscopic display by a 7th example.
FIG.
FIG. 12 is a front view of an optical delay board used for the display of FIG. 11.
FIG. 13
FIG. 13 is a cross-sectional view of the optical delay substrate of FIG.
FIG. 14
FIG. 9 is a front view of an optical delay board according to another embodiment of the present invention.
FIG.
FIG. 15 is a cross-sectional view of the optical delay substrate of FIG.
FIG.
FIG. 6 is a cross-sectional view of another embodiment of an optical delay substrate incorporating an electro-optical device.
FIG.
FIG. 9 is a plan view of an autostereoscopic display according to another embodiment.
FIG.
FIG. 18 is a front view of a substrate including a polarizing strip used in the display of FIG. 17.
FIG.
FIG. 18 is a plan view of the display of FIG. 17 showing the turning of the removable polarizer.
FIG.
FIG. 4 is a plan view of another embodiment using a removable polarizer.
FIG. 21
FIG. 9 is a plan view of yet another embodiment using a removable polarizer.
FIG.
FIG. 3 is a side view of a display with a hinged removable polarizer.
FIG. 23
FIG. 4 is a side view of a display including a removable polarizer provided on a roller.
FIG. 24
FIG. 4 is a side view of a display including a polarizer mounted on a case removably attached to the image forming display.
FIG. 25
FIG. 9 is a plan view of an autostereoscopic display according to another embodiment.
FIG. 26
FIG. 26 is a front view of a second LCD used for the display of FIG. 25.

Claims (38)

An autostereoscopic display device,
An image forming apparatus including display pixels arranged in rows and columns,
A first substrate including alternating strips, wherein the alternating strip includes strips having a first optical property, wherein the strips are separated by strips having different second optical properties; An apparatus comprising: a first substrate optically disposed before or after an image forming apparatus; and a polarizing substrate optically disposed before or after the image forming apparatus. Apparatus according to claim 1, wherein:
The image forming apparatus;
A first polarizing substrate optically disposed before or after said image forming apparatus, said substrate comprising alternating strips of polarizing film separated by transparent, non-polarizing strips;
A second polarizing substrate optically disposed before or after the image forming apparatus. 3. The apparatus of claim 2, wherein said imaging device comprises a transparent, electronically addressed liquid crystal display, said liquid crystal display comprising a liquid crystal layer addressable to an array of individual pixels. , Wherein said device further comprises a backlight source. 4. Apparatus according to claim 3, wherein said alternating strips are arranged vertically. 5. The apparatus according to claim 4, wherein the transparent strips are spaced according to the formula: p = 2 / ((1 / w)-(I / e)), where p is the pitch of the slit and w is the pitch of the slit. A device wherein the horizontal pixel pitch of the LC layer in an electronically addressed liquid crystal display, and e is the average separation of the observer's eyes. The apparatus of claim 5, wherein the width of the transparent strip is about half the width of the strip of polarizing film. 5. The device according to claim 4, further comprising a second liquid crystal panel including a liquid crystal layer without a pixel structure, wherein a voltage is applied over the entire surface of the second liquid crystal panel to reduce a liquid crystal of the layer. A device that changes molecular orientation. An apparatus according to claim 7, wherein
The second polarizing substrate arranged toward an observer,
The image forming liquid crystal display disposed behind the second polarizing substrate;
The first polarizing substrate disposed behind the image forming liquid crystal display;
The second liquid crystal panel disposed behind the first polarizing substrate;
An apparatus comprising: a rear polarizer disposed behind the second liquid crystal panel; and the backlight source disposed behind the rear polarizer. An apparatus according to claim 7, wherein
The second polarizing substrate arranged toward an observer of the device,
The image forming liquid crystal display disposed behind the second polarizing substrate;
A polarizer after being placed behind the image forming liquid crystal display,
The second liquid crystal panel disposed behind the rear polarizer;
An apparatus, comprising: the first polarizing substrate disposed behind the second liquid crystal panel; and the backlight source disposed behind the second polarizing substrate. An apparatus according to claim 7, wherein
A pre-polarizer placed towards the observer of the device,
The second liquid crystal panel disposed behind the front polarizer;
The first polarizing substrate disposed behind the second liquid crystal panel;
The image forming liquid crystal display disposed behind the first polarizing substrate;
Apparatus comprising: the second polarizing substrate disposed behind the imaging liquid crystal display; and the backlight source disposed behind the second polarizing substrate. An apparatus according to claim 7, wherein
The first polarizing substrate arranged toward an observer of the device,
The second liquid crystal panel disposed behind the first polarizing substrate;
A front polarizer disposed behind the second liquid crystal panel;
The image forming liquid crystal display disposed behind the front polarizer;
Apparatus comprising: the second polarizing substrate disposed behind the imaging liquid crystal display; and the backlight source disposed behind the second polarizing substrate. 2. The apparatus according to claim 1, wherein the image forming apparatus includes an emissive display, and the apparatus further includes a liquid crystal panel including a liquid crystal layer without a pixel structure, and applies a voltage over the entire surface thereof. An apparatus comprising: a liquid crystal panel that changes the molecular orientation of the liquid crystal of said layer by doing so, a first polarizing substrate comprising alternating strips of polarizing film separated by transparent, non-polarizing strips, and a second polarizing substrate. An apparatus according to claim 12, wherein
The first polarizing substrate arranged toward an observer of the device,
The liquid crystal panel disposed behind the first polarizing substrate;
An apparatus, comprising: the second polarizing substrate disposed behind the liquid crystal panel; and the emissive display disposed behind the second polarizing substrate. An apparatus according to claim 12, wherein
The second polarizing substrate arranged toward an observer of the device,
The liquid crystal panel disposed behind the second polarizing substrate;
An apparatus, comprising: the first polarizing substrate disposed behind the liquid crystal panel; and the emissive display disposed behind the first polarizing substrate. 3. The device according to claim 2, further comprising a liquid crystal panel including a liquid crystal layer without a pixel structure, wherein a voltage is applied over the entire surface of the second liquid crystal panel, and the liquid crystal molecules of the layer are molecularly aligned. A device that changes 16. The device according to claim 15, wherein the device is switchable between autostereoscopic imaging and 2D viewing by applying and removing a voltage to a liquid crystal display without a pixel structure. 2. The apparatus of claim 1 wherein said first substrate includes an optical delay substrate including a first alternating strip that delays a component of linearly polarized light passing therethrough by half a wavelength, said first strip passing therethrough. A device separated by a second alternating strip that delays the linearly polarized light components by one wavelength. 18. The apparatus of claim 17, wherein said imaging device comprises a transparent, electronically addressed liquid crystal display, said liquid crystal display comprising a liquid crystal layer addressable to an array of individual pixels. , Wherein said device further comprises a backlight source. 20. The device according to claim 18, wherein said staggered strips are arranged vertically. A device according to claim 1, wherein said one-wavelength strips are spaced according to the formula p = 2 / ((1 / w)-(1 / e)), where p is the pitch of the slit and w is the electronically A device wherein the horizontal pixel pitch of the LC layer in the addressed liquid crystal display, and e is the average separation of the observer's eyes. 21. The apparatus of claim 20, wherein the width of the one-wavelength strip is about half the width of the half-wavelength strip. 20. The apparatus of claim 17, wherein the half-wave strips have been etched from the substrate between the single-wavelength strips. 23. The apparatus of claim 22, wherein the first substrate further comprises a non-delay laminate over these half-wave and one-wave strips, wherein the laminate is from the junction of these half-wave and one-wave strips. For reducing diffraction and scattering of light. 18. The apparatus according to claim 17, further comprising a movable polarizer, wherein the movable polarizer is operatively disposed between the image forming devices and optically associated with the image forming device. When the movable polarizer is in its operating position, the observer can see an autostereoscopic image, and when the movable polarizer is in its inoperable position, it can be observed. A device that allows a 2D image to be seen by a person. 3. The device according to claim 2, wherein the non-polarizing strip of the first polarizing substrate is colorless. 3. The apparatus of claim 2, wherein the non-polarizing strip of the first polarizing substrate is colored to filter the light passing therethrough to a desired degree. A display device,
An image forming apparatus including display pixels arranged in rows and columns,
An apparatus comprising: a first polarizing substrate permanently disposed before or after the image forming apparatus; and a second polarizing substrate removably disposed before or after the image forming apparatus. 28. The apparatus according to claim 27, wherein the second polarizing substrate is optically disposed before or after an image forming apparatus, and a viewer of the apparatus can view an autostereoscopic image. 29. The apparatus according to claim 28, wherein when the second polarizing substrate is removed before or after the image forming apparatus, an observer of the apparatus can view a 2D image. 29. The apparatus according to claim 28, wherein when the second polarizing substrate is optically disposed at a second, opposite position with respect to the image forming apparatus, a 2D image is visible to a viewer of the apparatus. 28. The apparatus according to claim 27, wherein said second polarizing substrate is hinged to said image forming apparatus. 28. The apparatus according to claim 27, wherein the second polarizing substrate is flexible and mounted on a roller. 28. The apparatus according to claim 27, wherein said second polarizing substrate is mounted on a frame rather than being removably attachable to an image forming apparatus. 28. The apparatus according to claim 27, wherein the first polarizing substrate comprises alternating strips of polarizing film separated by alternating transparent, non-polarizing strips. 36. The apparatus according to claim 35, wherein the first polarizing substrate and the second polarizing substrate are on the same side of the image forming device when the second polarizing substrate is optically disposed with respect to the image forming device. Equipment located in the. 36. The apparatus according to claim 35, wherein said imaging device comprises a transparent, electronically addressed liquid crystal display, said liquid crystal display comprising a liquid crystal layer addressable to an array of individual pixels. And the apparatus further comprises a backlight source, and the apparatus further comprises a third polarizing substrate on the liquid crystal display opposite the first polarizing substrate. 28. The apparatus according to claim 27, further comprising an optical delay substrate optically disposed before or after the image forming apparatus, wherein the optical delay substrate delays a linearly polarized light component passing therethrough by a half wavelength. Apparatus comprising a first staggered strip, said first strip being separated by a second staggered strip which delays the passing linearly polarized light component by one wavelength. 38. The apparatus of claim 37, wherein when the second polarizing substrate is optically disposed with respect to the image forming device, the optical delay substrate and the second polarizing substrate are on the same side of the image forming device. Equipment that is located.