Light modulating module and image display

The disclosure provides a light modulating module attached on a display side of a reflective display apparatus, including: a light source portion capable of providing an illumination light beam, wherein the illumination light beam is capable of being transmitted to the reflective display apparatus, and the reflective display apparatus is adapted to reflect the illumination light beam to generate an image light beam; and an image light modulating device is disposed above the reflective display apparatus and disposed in a light path of the image light beam, wherein the image light modulating device is capable of modulating a direction and/or a polarization state of the image light beam, and the image light beam is emitted to either a left or right eye of a viewer to form an autostereoscopic image perceivable to the viewer after the image light beam passes through the image light modulating device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosure relates to a 3D image display, and in particular relates to a light modulating module thereof.

2. Description of the Related Art

Displays capable of showing stereoscopic images or animations are called three-dimensional (3D) image displays. Major developments in the 3D display fields have led to two types of technologies: a polarized glasses type and a naked-eye type. Meanwhile, 3D display effects may also be theoretically accomplished by using holography. However, holography needs interference of several light beams to display 3D images.

In the conventional 3D image displays, whether the naked-eye type or the polarized glasses type, a light modulating module is fixed on a display apparatuses. A user cannot view 3D images by an original 2D image display. The only way to view 3D images is buy a new 3D image display. Accordingly, a moveable light modulating module capable of being attached on a 2D image display to perform 3D images is called-for.

BRIEF SUMMARY OF THE INVENTION

One embodiment of the disclosure provides a light modulating module, adapted to be attached on a display side of a reflective display apparatus, comprising: a light source portion capable of providing an illumination light beam, wherein the illumination light beam is capable of being transmitted to the reflective display apparatus, and the reflective display apparatus is adapted to reflect the illumination light beam to generate an image light beam; and an image light modulating device disposed above the reflective display apparatus and disposed in a light path of the image light beam, wherein the image light modulating device is capable of modulating a direction and/or a polarization state of the image light beam, wherein the image light beam is emitted to either a left or right eye of a viewer to form an autostereoscopic image perceivable to the viewer after the image light beam passes through the image light modulating device.

One embodiment of the disclosure provides a stereoscopic display module adapted to be applied to a reflective display apparatus, comprising: the described light modulating module; and a stereoscopic glasses comprising a right eye glass capable of transmitting the image light beam having a first polarization state and a left eye glass capable of transmitting the image light beam having a second polarization state, wherein the first polarization state is different from the second polarization state, wherein the image light beam is emitted to either a left or right eye of a viewer to form an auto stereoscopic image perceivable to the viewer after the image light beam is emitted out from the image light modulating device and passes through the stereoscopic glasses.

One embodiment of the disclosure provides an image display comprising: a reflective display apparatus, comprising a display panel having a plurality of pixels; and a light modulating module, disposed on the reflective display apparatus, comprising: a light source portion capable of providing an illumination light beam, wherein the illumination light beam is capable of being transmitted to the reflective display apparatus, and the reflective display apparatus is adapted to reflect the illumination light beam to generate an image light beam; and an image light modulating device disposed above the reflective display apparatus and disposed in a light path of the image light beam, wherein the image light modulating device is capable of modulating a direction and/or a polarization state of the image light beam, wherein the image light beam is emitted to either a left or right eye of a viewer to form an auto stereoscopic image perceivable to the viewer after the image light beam passes through the image light modulating device.

One embodiment of the disclosure provides an image display system, comprising: a reflective display apparatus, comprising a display panel having a plurality of pixels; and a light modulating module, disposed on the reflective display apparatus, comprising a light source portion capable of providing an illumination light beam, wherein the illumination light beam is capable of being transmitted to the reflective display apparatus, and the reflective display apparatus is adapted to reflect the illumination light beam to generate an image light beam; an image light modulating device disposed above the reflective display apparatus and disposed in a light path of the image light beam, wherein the image light modulating device is capable of modulating at least one of the direction and the polarity of the image light beam; and a stereoscopic glasses comprising a right eye glass capable of transmitting the image light beam having a first polarization state and a left eye glass capable of transmitting the image light beam having a second polarization state, wherein the first polarization state is different from the second polarization state, wherein the image light beam is emitted to either a left or right eye of a viewer to form an auto stereoscopic image perceivable to the viewer after the image light beam is emitted out from the image light modulating device and passes through the stereoscopic glasses.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows an image display of one embodiment in the disclosure. A light modulating module B is attached on a reflective display apparatus A including a display panel having a plurality of pixels. The reflective display can be an electrophoretic electronic ink display, a chlorestic liquid crystal display, or the likes. The light modulating module B includes a light source portion I and an image light modulating device such as a reflective polarizer3. The light source portion I emits an illumination light beam100to be transmitted to the reflective display apparatus A and then reflected to generate an image light beam. A polarization state of the image light beam is then modulated by the reflective polarizer3in a light path of the image light beam, such that the image light beam is then emitted to either a left or right eye of a viewer to form an auto stereoscopic image for the viewer after the image light beam passes through the reflective polarizer3.

In one embodiment, the light source portion includes a plane light source200disposed between the image light modulating device B and the reflective display apparatus A. The plane light source200may include a light emitting device1and a light guide device2. The light emitting device1can be a light emitting diode (LED), a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), an exterior electrode fluorescent lamp (EEFL), or the likes. The light guide device2includes an image light emitting surface2A, an image light incident surface2B opposite to the image light emitting surface2A, and an illumination light incident surface2C perpendicular to the image light incident surface2B and the image light emitting surface2A. As shown inFIG. 1, the light emitting device1is disposed adjacent to the illumination light incident surface2C of the light guide device2. As such, an illumination light beam100emitted by the light emitting device1travels through the illumination light incident surface2C and the image light incident surface2B, and then enters the reflective display apparatus A. The illumination light beam100is then reflected to generate an image light beam. The image light beam, traveling through the image light incident surface2B and the image light emitting surface2A, is then modulated by the reflective polarizer3to be emitted to either a left or right eye of a viewer to form an auto stereoscopic image for the viewer. In one embodiment, the light guide device2further includes a plurality of microstructures2D disposed on the image light incident surface2B. Furthermore, the microstructures2D include a plurality of quantum dots having a distribution density increasing along a direction away from the illumination light incident surface. In other words, the quantum dots distribution near the top of the microstructures2D is denser than that near the bottom of the microstructures2D. The microstructures2D and the quantum dots thereof may further enhance a uniformity of the image light beam distribution.

The reflective polarizer3can be a linear reflective polarizer or a circular reflective polarizer. In one embodiment, the reflective polarizer3includes a first portion and a second portion. The first portion substantially reflects the image light beam having a first polarization state and substantially transmits the image light beam having a second polarization state. The second portion substantially reflects the image light beam having the second polarization state and substantially transmits the image light beam having the first polarization state. The first polarization state is different from the second polarization state. In one embodiment, the reflective polarizer3can be a wire grid polarizer including a wire grid disposed on a substrate. As shown inFIG. 2, the wire grid includes a plurality of wires201A aligned in parallel corresponding to a first direction in the first portion203A, and a plurality of wires201B aligned in parallel corresponding to a second direction in the second portion203B, respectively. The wires201A and201B can be composed of an electrically conductive material, e.g. metal such as aluminum, silver, and gold. The wires201A and201B can be nano-sized wires separated by nano-scaled spaces205. For example, the spaces205may have a width of 10 nm to 250 nm, and the ratio of the wires201A and201B to the spaces205is 25% to 75%. In another embodiment, the reflective polarizer3includes first and second portions of the multi-layered stack of alternating layers comprising a first material and a second material with different refractive indexes. The first portion of the multi-layered stack of alternating layers substantially reflects the image light beam having a first polarization state and substantially transmits the image light beam having a second polarization state. The second portion of the multi-layered stack of alternating layers substantially reflects the image light beam having a second polarization state and substantially transmits the image light beam having a first polarization state. The first polarization state is different from the second polarization state. For an example of the reflective polarizer3, reference may be made to U.S. Pat. No. 5,122,905. When the reflective polarizer3is selected as the image light modulating device, a viewer should wear stereoscopic glasses including a right eye glass and a left eye glass. The right eye glass transmits the image light beam having the first polarization state, and the left eye glass transmits the image light beam having the second polarization state.

In one embodiment, the reflective polarizer3substantially reflects an image light beam having a first polarization state and substantially transmits an image light beam having a second polarization state. The first polarization state is different from the second polarization state. Still in this embodiment, the image light modulating device further includes a fractional wave plate4disposed on the reflective polarizer3, as shown inFIG. 3. The fractional wave plate4includes a quarter wave plate or a half wave plate, such that half of the image light beam having the first polarization state is transferred to an image light beam having the second polarization state. In one embodiment, the reflective polarizer3can be a wire grid polarizer including a wire grid disposed on a substrate. As shown inFIG. 4, the wire grid includes a plurality of wires201A aligned in parallel corresponding to a first direction in all portions. In another embodiment, the reflective polarizer3is a multi-layered stack of alternating layers comprising a first material and a second material with different refractive indexes. For an example of the reflective polarizer3, reference may be made to U.S. Pat. No. 5,122,905. When the reflective polarizer3and the functional wave plate4are selected as the image light modulating device, a viewer should wear stereoscopic glasses including a right eye glass and a left eye glass. The right eye glass transmits the image light beam having the first polarization state, and the left eye glass transmits the image light beam having the second polarization state.

FIG. 5shows an image display of one embodiment in the disclosure. A light modulating module B is attached on a reflective display apparatus A including a display panel having a plurality of pixels. The reflective display can be an electrophoretic electronic ink display, a chlorestic liquid crystal display, or the likes. The light modulating module B includes a light source portion I and an image light modulating device such as a light directing device5. The light source portion I emits an illumination light beam100to be transmitted to the reflective display apparatus A and then reflected to generate an image light beam. A direction of the image light beam is then modulated by the light directing device5in a light path of the image light beam, such that the image light beam is then refracted to either a left or right eye of a viewer to form an auto stereoscopic image for the viewer after the image light beam passes through the light directing device5. The light source portion is similar to the previously described embodiment and omitted here. The light directing device5can be a lenticular film having a plurality of microlenses, a plurality of prisms, or a plurality of cylinders, as shown inFIG. 5. In another embodiment, the light directing device5includes an adjusting unit61, a first electrode63, a second electrode65, and a plurality of variable lenses67formed by a birefringence polar fluid, as shown inFIG. 6. The adjusting unit61adjusts a driver voltage from a driver source to the first electrode63and the second electrode65, thereby modulating an arrangement of the birefringence polar fluid of the plurality of the variable lenses67. As such, the direction of the image light beam is refracted to either a left or right eye of the viewer without wearing stereoscopic glasses. The birefringence polar fluid can be a liquid crystal element. In addition, the light directing device may further include an alignment layer (not shown) on the second electrode65to align the birefringence polar fluid of the variable lenses67.

FIG. 7shows an image display of one embodiment of the disclosure. A light modulating module B is attached on a reflective display apparatus A including a display panel having a plurality of pixels. The reflective display can be an electrophoretic electronic ink display, a chlorestic liquid crystal display, or the likes. The light modulating module B includes a light source portion I and an image light modulating device such as a 3D barrier layer7. The light source portion I emits an illumination light beam100to be transmitted to the reflective display apparatus A and then reflected to generate an image light beam. A direction of the image light beam is then modulated by the 3D barrier layer7in a light path of the image light beam, such that the image light beam is then emitted to either a left or right eye of a viewer to form an auto stereoscopic image for the viewer after the image light beam passes through the 3D barrier layer7. The 3D barrier layer7has light shielding portions7A and light transmitting slits7B, as shown inFIG. 7. The positions of the light shielding portions7A and the light transmitting slits7B are fixed inFIG. 7. In another embodiment, the positions of the light shielding portions8A and the light transmitting slits8B of the 3D barrier layer8are variable, as shown inFIG. 8. The 3D barrier layer8includes a bottom electrode81, a top electrode85, and a liquid crystal layer83disposed therebetween. While a voltage is applied to the liquid crystal layer83, the light shielding portions8A and the light transmitting slits8B are formed. If the liquid crystal layer83is a bistable liquid crystal, the voltage can be re-zeroed to save energy after forming the light shielding portions8A and the light transmitting slits8B. In one embodiment, an additional polarizer layer87can be formed under the bottom electrode81and/or on the top electrode85. Note that the viewer watching the image display including the 3D barrier layer may watch auto stereoscopic images without wearing stereoscopic glasses.

In one embodiment, a light source portion is disposed on the image light modulating device (such as an angular adjustable reflective polarizing device6on a reflective polarizer3), as shown inFIG. 9. The image light modulating device is disposed between the light source portion and the reflective display apparatus A. The reflective polarizer3is similar to that in embodiments ofFIGS. 1 and 2, having a first portion and second portion of wires arranged in different directions or of different reflective polarizers. The angular adjustable reflective polarizing device6has a plurality of the switchable light modulating cells60. Each of the switchable light modulating cells60comprises a polarizer67, a first electrode61A, a second electrode61B, a compartment63, and a first and second light modulating media65A and65B filled in the compartment63. The first light and second light modulating media65A and65B are substantially immiscible and are of different refractive indices. The polarizer67is on a boundary between the first light and second light modulating media65A and65B and is capable of being adjusted with a variation of the boundary between the first light and second light modulating media65A and65B driven by voltage difference among the first and second electrodes61A and61B. Reference may be made to U.S. application Ser. Nos. 13/221,321 and 13/016,384 for the positions of the first and second electrode, the cross-sectional shape of the compartment63, and compositions of the first and second light modulating media65A and65B ofFIG. 9, and are not limited thereto. The polarizer67can be a multilayer stack of alternating layers comprising a first material and a second material of different refractive indexes. The polarizer67reflects an image light beam (or an ambient light) having a first polarization state and substantially transmits an image light beam (or an ambient light) having a second polarization state. The first polarization state is different from the second polarization state. The reflected image light beam (having the first polarization state) will incident into another switchable light modulating cell60. The compartment63of the switchable light modulating cell60includes a partition wall69disposed between two adjacent switchable light modulating cell60. The light source portion68is disposed on the partition wall69. The light source portion68includes a light transparent window, wherein the light transparent window comprises a light transparent portion66and a frame64. The frame64includes an absorber64A and a reflection portion64B disposed between the absorber64A and the partition wall69. An ambient light900is capable of entering the switchable light modulating cell60by passing the light transparent portion68of the light transparent window. For a first set of switchable light modulating cell60(e.g. the rightmost one and the likes), the ambient light900having a second polarization state will travel through the polarizer67in the switchable light modulating cell60and the reflective polarizer3(the second portion) to enter and reflected by the reflective display apparatus A, thereby generating an image light beam. The image light beam having a second polarization state then travels through the reflective polarizer3(the second portion) and the polarizer67in the switchable light modulating cell60to enter either a left eye (or right eye) of a viewer wearing stereoscopic glasses. For the first set of switchable light modulating cells60(e.g. the leftmost one and the likes), the ambient light900having a first polarization state will be reflected by a polarizer67in the first set of the switchable light modulating cells60, and then travels through the partition wall69to a second set of switchable light modulating cells60. The reflected ambient light will travel through the reflective polarizer3(the first portion), and then enters and be reflected by the reflective display apparatus A corresponding to the second set of switchable light modulating cells60, thereby generating an image light beam having the first polarization state. The image light beam having the first polarization state is then travel through the reflective polarizer3(the first portion) and the polarizer67in the second set of switchable light modulating cells60to enter either a left eye (or right eye) of a viewer wearing stereoscopic glasses. For the second set of switchable light modulating cells60(e.g. the leftmost one and the likes), the ambient light900having a first polarization state will travel through the polarizer67in the switchable light modulating cell60and the reflective polarizer3(the first portion) to enter and be reflected by the reflective display apparatus A, thereby generating an image light beam. The image light beam having the first polarization state then travels through the reflective polarizer3(the first portion) and the polarizer67in the switchable light modulating cell60to enter either a left eye (or right eye) of a viewer wearing stereoscopic glasses. For the second set of switchable light modulating cells60(e.g. the leftmost one and the likes), the ambient light900having a second polarization state will be reflected by a polarizer67in the second set of switchable light modulating cells60, and then absorbed by the absorber64A (or reflected by the reflection portion64B to the first set of switchable light modulating cells60). In this embodiment, no additional plane light source (such as a light emitting device and a light guide device) is disposed between the reflective display apparatus A and the image light modulating device. In other words, the ambient light900replaces the illumination light beam100in previously described embodiments.

In one embodiment, a light source portion is disposed on the image light modulating device (such as a micro electro mechanical system (MEMS) device10on a transparent substrate101on the reflective polarizer3), as shown inFIG. 10. The micro electro mechanical system device10includes a moveable optical element10A and an actuator (not shown) to actuate the optical element10A. The moveable optical element10A is capable of being held at any one of a plurality of positions on the transparent substrate101. For example, the moveable optical element10A is a polarizer capable of substantially reflecting an image light beam (and an ambient light) having a first polarization state and substantially transmitting an image light beam (and an ambient light) having a second polarization state, wherein the first polarization state is different from the second polarization state. The motion (e.g. the polarizer position, the polarizer tilt angle, and the likes) of the polarizer is controlled by the actuator. The ambient light having a second polarization state will travel through the moveable optical element10A and the reflective polarizer3to enter and be reflected by the reflective display apparatus A, thereby generating an image light beam. The image light beam having a second polarization state then travels through the reflective polarizer3and the moveable optical element10A to enter either a left eye and right eye of a viewer wearing stereoscopic glasses. In this embodiment, no more plane light source (such as a light emitting device and a light guide device) is disposed between the reflective display apparatus A and the image light modulating device. In other words, the ambient light replaces the illumination light beam100in previously described embodiments.

Whether the light modulating module B includes, e.g. the light source portion I and the image light modulating device (such as a reflective polarizer3) inFIG. 1, the light source portion I and the image light modulating device (such as a reflective polarizer3and a fractional wave plate4thereon) inFIG. 3, a light source portion I and an image light modulating device (such as a light directing device5) inFIGS. 5 and 6, a light source portion I and an image light modulating device (such as a 3D barrier layer7or8) inFIGS. 7 and 8, the light source portion on the image light modulating device (such as an angular adjustable reflective polarizing device6on a reflective polarizer3) inFIG. 9, or the light source portion on the image light modulating device (such as the micro electro mechanical system (MEMS) device10on the transparent substrate101on the reflective polarizer3) inFIG. 10, the light modulating module B is not fixed on the reflective display apparatus A. Note that the light modulating module B and the reflective display apparatus A can be separately made at different factories or even different countries, and then combined by a user to perform stereoscopic images. In addition, the reflective display apparatus A is input 3D image signals to display 3D images. The reflective display apparatus A cannot display 3D images by the input of 2D image signals, even if the light modulating module B is attached on the reflective display apparatus A.