Patent Application
20220297603
The present disclosure relates to the field of light reflection devices, and particularly relates to dimmable light reflection devices, such as an automotive interior rearview mirror device. In some embodiments, the device implements automatic adjustment of reflectivity according to a detected intensity of light, e.g., from the rear of a vehicle, and can effectively protect a driver of the vehicle from the interference of strong light from the rear of the vehicle.
Traditional dimmable automotive interior rearview mirror uses mat paper color change technology. When the interior rearview mirror light-sensitive components receive a certain intensity of light from the rear of the car, a driver module outputs a driving current to induce an electrochemical reaction in an electrochromic medium layer, which undergoes a color change from a transparent state to a dark state, thus adjusting the reflectivity of the rearview mirror. However, such electrochromic technology is generally complicated and associated with high cost. Also, low reflectivity is typically not low enough, and the response speed is slow, usually up to 6 seconds. Furthermore, strong light from the rear of the vehicle generally cannot be well blocked quickly, which can pose a safety hazard.
The present disclosure provides a dimmable reflective device generally. In some embodiments, the present disclosure provides a dimmable mirror configured to be used in conjunction with a display device for display. For instance, the dimmable mirror may be used as an automotive interior rearview mirror device. The display may present streaming media such as a live video comprising images captured from a camera from an exterior of a vehicle. In some embodiments, such an automotive interior rearview mirror device or automotive sideview mirror device may include a dimming device, a streaming display, a light-sensitive driving system, etc. In some embodiments, the streaming display is replaced with a mirror. The dimming device may include one or more layers of liquid crystal layer and semi-translucent and semi-reflective film. When the light-sensitive element senses strong light from the rear of the vehicle, such as the strong light from another vehicle's high beam at night, the corresponding signal can be fed back to the driving system, and the driving system outputs the corresponding intensity of an electric field to drive the liquid crystal layer to realize the reflectivity adjustment of the rearview mirror. Such an arrangement may effectively protect the driver from the interference of the strong light from the rear of the vehicle and effectively improve the night driving safety.
When the content of the rearview mirror streaming display needs to be displayed, the dimming device can exhibit a high transmittance, effectively passing the light emitted from the display, making the image of the display highly transparent and clear display.
An example apparatus having a layered structure comprises a transreflective layer configured to transmit light in a transmissive polarization orientation and reflect light in a reflective polarization orientation. The apparatus further may comprise at least one guest host (GH) liquid crystal layer comprising non-cholesteric liquid crystal molecules having a non-helical structure and dichroic dye molecules, each of the at least one GH liquid crystal layer controllable to operate in at least two possible states including (1) a vertical state in which the liquid crystal molecules are oriented in a direction perpendicular to a plane corresponding to the at least one GH liquid crystal layer and (2) a planar state in which the liquid crystal molecules are oriented in a direction parallel to the plane corresponding to the at least one GH liquid crystal layer. The apparatus further may comprise a switchable quarter-wave layer positioned between the transreflective layer and the at least one GH liquid crystal layer, the switchable quarter-wave layer comprising an electronically controlled birefringence (ECB) retarder comprising liquid crystal molecules, wherein in a transmission mode, the layered structure is configured to transmit linearly polarized light originating from a first side of the layered structure through the layered structure to a second side of the layered structure, corresponding to a transmittance rate, wherein in a first reflection mode, the layered structure is configured to reflect light originating from the second side of the layered structure back toward the second side of the layered structure, corresponding to a first reflectivity rate, and wherein in a second reflection mode, the layered structure is configured to reflect light originating from the second side of the layered structure back toward the second side of the layered structure, corresponding to a second reflectivity rate less than the first reflectivity rate.
An example apparatus having a layered structure comprises a transreflective layer configured to transmit light in a transmissive polarization orientation and reflect light in a reflective polarization orientation. The apparatus further may comprise at least one guest host (GH) liquid crystal layer comprising liquid crystal molecules and dichroic dye molecules, each of the at least one GH liquid crystal layer controllable to operate in at least two possible states including (1) a vertical state in which the liquid crystal molecules are oriented in a direction perpendicular to a plane corresponding to the at least one GH liquid crystal layer and (2) a planar state in which the liquid crystal molecules are oriented in a direction parallel to the plane corresponding to the at least one GH liquid crystal layer, wherein in a transmission mode, the layered structure is configured to transmit linearly polarized light originating from a first side of the layered structure through the layered structure to a second side of the layered structure, corresponding to a transmittance rate, wherein in a first reflection mode, the layered structure is configured to reflect light originating from the second side of the layered structure back toward the second side of the layered structure, corresponding to a first reflectivity rate, and wherein in a second reflection mode, the layered structure is configured to reflect light originating from the second side of the layered structure back toward the second side of the layered structure, corresponding to a second reflectivity rate less than the first reflectivity rate.
An example apparatus having a layered structure comprises a reflective layer. The apparatus further may comprise at least one guest host (GH) liquid crystal layer comprising liquid crystal molecules and dichroic dye molecules, each of the at least one GH liquid crystal layer controllable to operate in at least two possible states including (1) a vertical state in which the liquid crystal molecules are oriented in a direction perpendicular to a plane corresponding to the at least one GH liquid crystal layer and (2) a planar state in which the liquid crystal molecules are oriented in a direction parallel to the plane corresponding to the at least one GH liquid crystal layer. The apparatus further may comprise a quarter-wave layer positioned between the reflective layer and the at least one GH liquid crystal layer, wherein in a first reflection mode, the layered structure is configured to reflect light originating from a first side of the layered structure back toward the first side of the layered structure, corresponding to a first reflectivity rate, and wherein in a second reflection mode, the layered structure is configured to reflect light originating from the first side of the layered structure back toward the first side of the layered structure, corresponding to a second reflectivity rate less than the first reflectivity rate.
An example apparatus having a layered structure comprises a reflective layer. The apparatus further may comprise a first guest host (GH) liquid crystal layer comprising liquid crystal molecules and dichroic dye molecules. The apparatus further may comprise a second GH liquid crystal layer positioned between the reflective layer and the first GH liquid crystal layer, the second GH liquid crystal layer comprising liquid crystal molecules and dichroic dye molecules, wherein each of the first and second GH liquid crystal layers is controllable to operate in at least two possible states including (1) a vertical state in which the liquid crystal molecules are oriented in a direction perpendicular to a plane corresponding to the at least one GH liquid crystal layer and (2) a planar state in which the liquid crystal molecules are oriented in a direction parallel to the plane corresponding to the at least one GH liquid crystal layer, and wherein in a first reflection mode, the layered structure is configured to reflect light originating from a first side of the layered structure back toward the first side of the layered structure, corresponding to a first reflectivity rate, and wherein in a second reflection mode, the layered structure is configured to reflect light originating from the first side of the layered structure back toward the first side of the layered structure, corresponding to a second reflectivity rate less than the first reflectivity rate.
Embodiments of the present disclosure provide a dimmable mirror device (e.g., interior rearview mirror device), which can realize automatic adjustment of reflectivity according to the intensity of light (e.g., from the rear of the vehicle). Embodiments of the disclosure can, for example, effectively protect the driver from the interference of strong light from the rear of the vehicle. At the same time, the device can optionally be combined with display of content, such as media streaming achieved through high transmission and high-definition display of images, to enrich human-computer interaction.
According to various embodiments, an apparatus having a layered structure is disclosed. A transreflective layer is configured to transmit light in a transmissive polarization orientation and reflect light in a reflective polarization orientation. At least one guest host (GH) liquid crystal layer comprising liquid crystal molecules and dichroic dye molecules. Each of the at least one GH liquid crystal layer is controllable to operate in at least two possible states, including (1) a vertical state in which the liquid crystal molecules are oriented in a direction perpendicular to a plane corresponding to the at least one GH liquid crystal layer and (2) a planar state in which the liquid crystal molecules are oriented in a direction parallel to the plane corresponding to the at least one GH liquid crystal layer. In a transmission mode, the layered structure is configured to transmit linearly polarized light originating from a first side of the layered structure through the layered structure to a second side of the layered structure, corresponding to a transmittance rate. In a first reflection mode, the layered structure is configured to reflect light originating from the second side of the layered structure back toward the second side of the layered structure, corresponding to a first reflectivity rate. In a second reflection mode, the layered structure is configured to reflect light originating from the second side of the layered structure back toward the second side of the layered structure, corresponding to a second reflectivity rate less than the first reflectivity rate.
The present disclosure proposes mirror device comprising a plurality of solutions as follows. The mirror device may include a display in some embodiments and may include no display in other embodiments. The mirror device may be used in a vehicular application and may be implemented in an interior and/or exterior region of a vehicle. For example, embodiments of the mirror device may be implemented as an interior rearview mirror and/or an exterior side mirror for a vehicle.
I. Single Layer Cholesteric LC
The first directional layer 206 and the second directional layer 210 are arranged on opposite sides of and sandwich the liquid crystal (LC) layer 208. Each of the directional layers 206 and 210 is characterized by a surface having grooves along a certain direction. Such grooves (e.g., ridges and troughs) may be formed by rubbing a base material, such as a polyimide, with another material, such as a cotton ball or cloth, along a certain direction. Liquid crystal molecules coming into contact with the directional layers 206 and 210 tend to align, or anchor, themselves with their longitudinal axes in parallel to the grooves. The strength of such alignment is associate with a characteristic anchoring energy, which may be as high as 10−3 Joules/meter2, for example. The first conductive layer 204 and the second conductive layer 212 are arranged on opposing sides of and sandwich the liquid crystal layer 208, the first directional layer 206, and the second directional layer 210. A voltage applied across the first conductive layer 204 and the second conductive layer 212 generates an electrical field that impacts the orientation of the liquid crystal molecules within the liquid crystal layer 208. Different liquid crystal orientations may be achieved by operation of the applied voltage. In one embodiment, when no voltage is applied, the liquid crystal molecules are naturally in a cholesteric phase and exhibit a chiral/helical orientation. That is, the liquid crystal molecules twist, for example, with a particular chiral pitch, p. When a voltage (e.g., beyond a certain threshold) is applied the liquid crystals may become orientated based on the electrical field generated by the first conductive layer 204 and the second conductive layer 212. For example, the electric field may cause the liquid crystal molecules to align such that their long axes are perpendicular to the plane of the liquid crystal layer 208.
The first base (substrate) material layer 202 and the second base (substrate) material layer 214 are arranged on opposite sides of and sandwich the liquid crystal (LC) layer 208, the first directional layer 206, the second directional layer 210, the first conductive layer 204, and the second conductive layer 212. In some embodiments, the first base (substrate) material layer 202 and the second base (substrate) material layer 214 provide mechanical stability to the various layers mentioned above. A stacked structure comprising these layers—e.g., the liquid crystal (LC) layer 208, the first directional layer 206, the second directional layer 210, the first conductive layer 204, the second conductive layer 212, the first base (substrate) material layer 202, and the second base (substrate) material layer 214—may be manufactured as a flexible, multi-layered liquid crystal “film” which may be attached to the semi-transmissive and semi-reflective (“transreflective”) film 216. An example of the transreflective film 216 a 3M dBEF semi-transparent, semi-transmissive film. The transreflective film 216 may be attached to the display device 220. Attachment of the various layers mentioned above to each other and/or other layers may be achieved by using one or more adhesive layer(s), such as the OCA adhesive layer 218.
While multiple layers of materials are described herein, the overall dimmable mirror apparatus 200 is nevertheless described as having as a “single-layer” cholesteric liquid crystal. This is because only a single LC layer is present in this particular embodiment of the disclosure. In other embodiments, described in subsequent sections of the disclosure, liquid crystal molecules may reside in two or more LC layers, which may work in conjunction with one another to effectuate the dimming and/or display transmission operations of the overall apparatus. Also, note that
A. Transmission Mode (e.g.,
During the display transmission mode, the display 242 (e.g., streaming media display) may emit display light in the form of linearly polarized light. The polarization direction of the linearly polarized light may be parallel to the transmission direction/axis 250 of the transreflective film 244. As an example, the transmission direction/axis 250 of the transreflective film 244 may be in a vertical direction. By contrast, the reflection direction/axis 252 of the transreflective film 244 may be in a horizontal direction. Because the polarization direction of the linearly polarized light is in the vertical direction, the linearly polarized light mostly transmits through the transreflective film 244. For example, the light transmission rate of the linearly polarized light through the transreflective film 244 may be ≥90%.
The linearly polarized light may transmit through both the transreflective film 244 and the liquid crystal layer 246. Here, the liquid crystal layer 246 is in the open state. The long axis of the dichroic dye liquid crystal molecules within the liquid crystal layer 246 is perpendicular to the plane of the substrate. This may be achieved, for example, by applying an appropriate voltage across conductor layers (not shown) that sandwich the liquid crystal layer 246. At this time, the light transmitted through the liquid crystal layer experiences weak absorption. For example, the liquid crystal layer transmittance rate may be ≥85%. The light emitted by the streaming media display 242 may experience, through the entire layered structure, a total transmittance rate of ≥76.5%. This may correspond to a relatively high brightness of the display. Such transmittance achieves high transmission and high definition of the display.
In some embodiments, if a strong light is directed toward the device from the user side during streaming media mode, the LC layer is kept in the “open” state (state in which the liquid crystal molecules are oriented in a direction perpendicular to the plane of the LC layer), to allow display light to continue to project toward the user. Here, a light-sensitive element such as a light sensor (not shown) may be incorporated to sense light (e.g., ambient light) originating from user side (i.e., right side of
B. Reflection Modes (e.g.,
During one or more reflection modes, the streaming display 242 is turned off, forming a black background, according to various embodiments of the disclosure. There may also exist more than one reflection mode, such as a high reflection mode and a low reflection mode, described in more detail below.
II. Double Layer LC
In many respects, operation of a first portion of the structure comprising the first base (substrate) material layer 302, first conductive layer 304, first directional layer 306, first liquid crystal (LC) layer 308, second directional layer 310, second conductive layer 312, and second base (substrate) material layer 314 may be similar to that of certain layers shown in
Similarly, operation of a second portion of the structure comprising the third base (substrate) material layer 322, third conductive layer 324, third directional layer 326, second liquid crystal (LC) layer 328, fourth directional layer 330, fourth conductive layer 332, and fourth base (substrate) material layer 334 may be akin in many respects to that of certain layers shown in
Furthermore, operation of a third portion of the structure comprising the transreflective film layer 340, OCA adhesive layer 342, and display layer 344 may be similar in many respects to that of certain layers shown in
Under some conditions (e.g., when a voltage is applied), the liquid crystals may be placed in an open state and become orientated such that their long axes are perpendicular to the plane of the first liquid crystal layer 308, as shown in
A. Transmission Mode (e.g.,
During the display transmission mode, the display 362 (e.g., streaming media display) may emit display light in the form of linearly polarized light. The polarization direction of the linearly polarized light may be parallel to the transmission direction/axis 370 of the transreflective film 364. As an example, the transmission direction/axis 370 of the transreflective film 364 may be in a vertical direction. By contrast, the reflection direction/axis 372 of the transreflective film 364 may be in a horizontal direction. Because the polarization direction of the linearly polarized light is in the vertical direction, the linearly polarized light mostly transmits through the transreflective film 364. For example, the light transmission rate of the linearly polarized light through the transreflective film 364 may be ≥90%.
The linearly polarized light may transmit through both the transreflective film 364, the first liquid crystal layer 366, and the second liquid crystal layer 368. Here, the first liquid crystal layer 366 and the second liquid crystal layer 368 are both in the open state. The long axis of the dichroic dye liquid crystal molecules within the first liquid crystal layer 366 and second liquid crystal layer 368 is perpendicular to the plane of the substrate. This may be achieved, for example, by applying an appropriate voltage across conductor layers (not shown) that sandwich each of the first liquid crystal layer 366 and the second liquid crystal layer 368. At this time, the light transmitted through the liquid crystal layers experiences weak absorption. For example, the combined liquid crystal layer transmittance rate for both LC layers may be ≥80%, which is slightly lower than that of the single-layer LC structure shown in
In some embodiments, if a strong light is directed toward the device from the user side during streaming media mode, the first and second LC layers are kept in the “open” state (state in which the liquid crystal molecules are oriented in a direction perpendicular to the plane of the LC layer), to allow display light to continue to project toward the user. Here, a light sensor (not shown) may be incorporated to sense light (e.g., ambient light) originating from user side (i.e., right side of
B. Reflection Modes (e.g.,
During one or more reflection modes, the streaming display 362 is turned off, forming a black background, according to various embodiments of the disclosure. There may also exist more than one reflection mode, such as a high reflection mode and a low reflection mode, described in more detail below.
For example, light traveling from the rear of the vehicle (e.g., from the right side of
III. Single Layer Non-Cholesteric LC
The GH liquid crystal layer 402 may comprise at least one guest host (GH) liquid crystal layer, which may include liquid crystal molecules and dichroic dye molecules. The at least one GH liquid crystal layer is controllable to operate in at least two possible states including (1) a vertical state in which the liquid crystal molecules are oriented in a direction perpendicular to a plane corresponding to the at least one GH liquid crystal layer and (2) a planar state in which the liquid crystal molecules are oriented in an x-y direction that is (a) parallel to the plane corresponding to the at least one GH liquid crystal layer and (b) configured to substantially absorb a component of light that is linearly polarized along the same x-y direction. The switchable quarter-wave layer 404 is positioned between the transreflective film 406 and the single GH liquid crystal layer 402. In some embodiments, the switchable quarter-wave plate 404 comprises an electronically controlled birefringence (EBC) retarder comprising liquid crystal molecules. As shown, the transreflective film 406 is configured to transmit light in a transmissive polarization orientation and reflect light in a reflective polarization orientation.
A. Transmission Mode
In a transmission mode (410), the display 408 is on and emits linearly polarized light, shown here in the “--” polarization. The linearly polarized light reaches the transreflective film 406. The transreflective film 406 is positioned such that its transmission axis is shown as “-” and is parallel to the polarization orientation of the linearly polarized light emitted from the display 408. Thus, the linearly polarized light from the display 408 passes through the transreflective film 406. Next, the linearly polarized light reaches the switchable quarter-wave plate 404, which is turned ON in the current mode. Here, when the switchable quarter-wave plate 404 is turned on (electric field applied), its liquid crystal molecules are in the open state and oriented in a vertical orientation that is perpendicular to the plane of the liquid crystal layer. As a result, the linearly polarized light passes through the switchable quarter-wave plate 404. The linearly polarized light next reaches the GH liquid crystal layer 402, which is in the OFF state. When the GH liquid crystal layer 402 is in the off state (no electric field is applied), its liquid crystal molecules are in the closed state and oriented in an orientation that is (a) parallel to the plane of the liquid crystal and (2) indicated by the “●●●” symbol (into the page). In such an orientation, the liquid crystal molecules of the GH liquid crystal layer 402 substantially absorb linearly polarized light oriented along the same “●●●” orientation. The rate of absorption may be adjustable. In some embodiments, the rate of absorption is greater than 50%. In a specific embodiment shown in
According to some embodiments, low reflection during media transmission (412) is also exhibited. Here, unpolarized light originating from the external environment (e.g., from behind the vehicle) may first reach the GH liquid crystal layer 402. In the current mode, as discussed, the GH liquid crystal layer 402 is in the OFF state (no electric field applied). The liquid crystal molecules of the GH liquid crystal layer 402, positioned in the “●●●” orientation, substantially absorb linearly polarized light oriented along the same “●●●” orientation. In the current example, the absorption rate is 92%. Thus, the GH liquid crystal layer 402 absorbs 92% of the component of the unpolarized light in the “●●●” orientation and allows 8% of the component of the unpolarized light in the “●●●” orientation to pass through. The GH liquid crystal layer 402 leaves the component of the unpolarized light in the “--” orientation mostly unaffected. The result light that leaves the GH liquid crystal layer 402 is mostly linearly polarized along the “--” orientation but also contains 8% of the component of the unpolarized light in the “●●●” orientation. This light reaches the switchable quarter-wave plate 404. The switchable quarter-wave plate 404 is in the ON state, with liquid crystal molecules in the open position, which allows light to pass through regardless of polarization. The resulting light reaches transreflective film 406, which allows linearly polarized light in the “--” orientation to pass through, while reflecting linearly polarized light in the “●●●” orientation. Thus, the transreflective film 406 reflects the 8% of the component of the unpolarized light in the “●●●” orientation. This light then reaches the quarter-wave plate 404 on the return path. The quarter-wave plate 404 is still in the ON state, and it allows light to pass through, regardless of polarization. Thus, the 8% of the component of the unpolarized light in the orientation passes through and reaches the GH liquid crystal layer 402. As discussed, the GH liquid crystal layer 402 is in the OFF state (no electric field applied), with liquid crystal molecules in the “●●●” orientation. The liquid crystal molecules in such an orientation absorb linearly polarized light in the “●●●” orientation according to an absorption rate of 92%, in this example (transmission rate of 8%). Thus, only 8% of the 8% of the component of the original unpolarized light in the “●●●” orientation is allowed to pass through. The resulting reflected light that exits the device 400 is only 8%*8%=0.64% of the component of the original unpolarized light in the “●●●” orientation. In this manner, very low reflection is achieved while the display 408 is on.
B. Reflection Modes
a. High Reflection Mode (414)
A high reflection mode 414 is shown with the display is off. Unpolarized light from the external environment (e.g., from behind the vehicle) may first reach the GH liquid crystal layer 402, which is turned ON. In this state, the liquid crystal molecules of the GH liquid crystal layer 402 are in the open position, which allows light to pass through regardless of polarization. The unpolarized light thus passes through the GH liquid crystal layer 402 and reaches the switchable quarter-wave plate 404. In the current mode, the switchable quarter-wave plate 404 is in the OFF state (electric field not applied) with liquid crystal molecules arranged so as to operate as a quarter-wave plate. The switchable quarter-wave plate 404 converts linearly polarized light in a first x-y orientation (e.g., “--” orientation) into right-handed circularly polarized (RHC) light. The switchable quarter-wave plate 404 converts linearly polarized light in a second x-y orientation (e.g., “●●●” orientation) into left-handed circularly polarized (LHC) light. The RHC light reaches the transreflective film 406, which converts the RHC light to reflected LHC light at a reduced intensity (e.g., 50%). The LHC light reaches the transreflective film 406, which converts the LHC light to reflected RHC light at a reduced intensity (e.g., 50%). Both components of light travel along the return path toward the switchable quarter-wave plate 404. The switchable quarter-wave plate 404 converts the reflected LHC light to linearly polarized light in the “●●●” orientation. The switchable quarter-wave plate 404 converts the reflected RHC light to linearly polarized light in the “--” orientation. The resulting unpolarized light is at a reduced intensity (e.g., 50%), and it passes through the GH liquid crystal layer 402, which is in the open state. Thus, the device 400 operates to provide high reflection in the current mode.
b. Low Reflection Mode (416)
A low reflection mode 416 is also shown with the display is off. Unpolarized light from the external environment (e.g., from behind the vehicle) may first reach the GH liquid crystal layer 402. In the current mode, the GH liquid crystal layer 402 is in the OFF state (no electric field applied). The liquid crystal molecules of the GH liquid crystal layer 402, positioned in the “●●●” orientation, substantially absorb linearly polarized light oriented along the same “●●●” orientation. In the current example, the absorption rate is 92%. Thus, the GH liquid crystal layer 402 absorbs 92% of the component of the unpolarized light in the “●●●” orientation and allows 8% of the component of the unpolarized light in the “●●●” orientation to pass through. The GH liquid crystal layer 402 leaves the component of the unpolarized light in the “--” orientation mostly unaffected. The result light that leaves the GH liquid crystal layer 402 is mostly linearly polarized along the “--” orientation.
In the current mode, the switchable quarter-wave plate 404 is in the OFF state (electric field not applied) with liquid crystal molecules arranged so as to operate as a quarter-wave plate. The switchable quarter-wave plate 404 converts linearly polarized light in a first x-y orientation (e.g., “--” orientation) into right-handed circularly polarized (RHC) light. Thus, the light that is mostly linearly polarized along the “--” orientation is converted to mostly RHC light. The mostly RHC light is reflected by the transreflective film and converted to reflected LHC light at a reduced intensity (e.g., 50%). The reflected LHC light reaches the switchable quarter-wave plate 404 on the return path. The switchable quarter-wave plate 404 converts the reflected LHC light to mostly linearly polarized light along the “●●●” orientation.
The mostly linearly polarized light along the “●●●” orientation reaches the GH liquid crystal layer 402. In the current mode, the switchable quarter-wave plate 404 is in the OFF state (electric field not applied) with liquid crystal molecules arranged so as to operate as a quarter-wave plate. The switchable quarter-wave plate 404 converts linearly polarized light in a first x-y orientation (e.g., “--” orientation) into right-handed circularly polarized (RHC) light. The switchable quarter-wave plate 404 converts linearly polarized light in a second x-y orientation (e.g., “●●●” orientation) into left-handed circularly polarized (LHC) light. The RHC light reaches the transreflective film 406, which converts the RHC light to reflected LHC light at a reduced intensity (e.g., 50%). The LHC light reaches the transreflective film 406, which converts the LHC light to reflected RHC light at a reduced intensity (e.g., 50%). Both components of light travel along the return path toward the switchable quarter-wave plate 404. The switchable quarter-wave plate 404 converts the reflected LHC light to linearly polarized light in the “●●●” orientation. The switchable quarter-wave plate 404 converts the reflected RHC light to linearly polarized light in the “--” orientation. The resulting unpolarized light is at a reduced intensity (e.g., 50%), and it passes through the GH liquid crystal layer 402. The GH liquid crystal layer 402 is in the OFF state (no electric field applied), with liquid crystal molecules in the “●●●” orientation. The liquid crystal molecules in such an orientation absorb linearly polarized light in the “●●●” orientation according to an absorption rate of 92%, in this example (transmission rate of 8%). Thus, the residual light that exits the GH liquid crystal layer 402 is substantially attenuated.
Note that in
IV. LC Layer and Quarter-Wave Plate, Without Display
A. High Reflection Mode (510)
A high reflection mode 510 is shown. Unpolarized light from the external environment (e.g., from behind the vehicle) may first reach the GH liquid crystal layer 502, which is turned ON. In this state, the liquid crystal molecules of the GH liquid crystal layer 502 are in the open position, which allows light to pass through regardless of polarization. The passage of light through liquid crystal molecules in the open position may occur with some degree of attenuation (which was not mentioned previously in the context of
B. Low Reflection Mode (512)
A low reflection mode 512 is also shown. Unpolarized light from the external environment (e.g., from behind the vehicle) may first reach the GH liquid crystal layer 502. In the current mode, the GH liquid crystal layer 402 is in the OFF state (no electric field applied). The liquid crystal molecules of the GH liquid crystal layer 502, positioned in the “●●●” orientation, substantially absorb linearly polarized light oriented along the same “●●●” orientation. In the current example, the absorption rate is 92%. Thus, the GH liquid crystal layer 402 absorbs 92% of the component of the unpolarized light in the “●●●” orientation and allows 8% of the component of the unpolarized light in the “●●●” orientation to pass through. The GH liquid crystal layer 502 leaves the component of the unpolarized light in the “--” orientation mostly unaffected. However, some absorption can still occur. Just as an example, the GH liquid crystal layer 502 may absorb 20% of the component of the unpolarized light in the “--” orientation and allow 80% of the component of the unpolarized light in the “--” orientation to pass through. The resulting light that leaves the GH liquid crystal layer 402 has a polarized component along the “●●●” orientation with a reduced intensity of 50%*8%=4%. The resulting light that leaves the GH liquid crystal layer 402 has a polarized component along the “--” orientation with a reduced intensity of 50%*80%=40%. This resulting light then reaches the non-switchable quarter-wave plate 504. The switchable quarter-wave plate 504 converts linearly polarized light in a first x-y orientation (e.g., “--” orientation) into right-handed circularly polarized (RHC) light. Thus, the light that is mostly linearly polarized along the “--” orientation is converted to mostly RHC light. The mostly RHC light is reflected by the mirror 506 and converted to reflected LHC light. The reflected LHC light reaches the non-switchable quarter-wave plate 504 on the return path. The non-switchable quarter-wave plate 504 converts the reflected LHC light to mostly linearly polarized light along the “●●●” orientation. In the present example, this reflected, mostly linearly polarized light has a polarized component along the “●●●” orientation with a reduced intensity of 50%*80%=40%, as well as a polarized component along the “--” orientation with a reduced intensity of 50%*8%=4%. The light reaches the GH liquid crystal layer 502. Again, the liquid crystal molecules of the GH liquid crystal layer 502, positioned in the “●●●” orientation, substantially absorb linearly polarized light oriented along the same orientation. The polarized light along the “●●●” orientation is thus further attenuated according to an attenuation rate of 8%. The polarized light along the “--” orientation is thus further attenuated according to an attenuation rate of 80%. Thus, the reflected light that exits the GH liquid crystal layer 502 has a polarized component along the “●●●” orientation with a reduced intensity of 50%*80%*8%=3.2%, as well as a polarized component along the “--” orientation with a reduced intensity of 4%*80%=3.2%. The total intensity of the resulting combined unpolarized light is thus 3.2%+3.2%=6.4% of the intensity of the unpolarized light that originally entered the device 500 from the external environment.
V. Double Layer Non-Cholesteric LC, without Display
A. High Reflection Mode (e.g.,
As shown in
B. Low Reflection Mode (e.g.,
For example, light traveling from the rear of the vehicle (e.g., from the right side of
VI. Drive Circuitry
Just as an example, the dimmable mirror apparatus 200 previously described with respect to
In one embodiment, the light-sensitive elements comprise a first light-sensitive element and a second light-sensitive element. The first light-sensitive element may be positioned toward the front of the car, to sense whether the environment outside the vehicle is day or night. When the sensed environment is day, the dimming device may be placed in a non-triggered, or non-working state. When the sensed environment for night, the dimming device can be triggered and placed in a working state and operated according to more specific measurements obtained by the second light-sensitive element. The second light-sensitive element may be positioned towards the rear of the vehicle, to detect the existence of glare from the rear side of the vehicle. When the light-sensitive element detects glare from the rear of the vehicle, the dimming device drive system 700 may provide corresponding signal feedback to effectuate a corresponding intensity of an electric field (e.g., providing a corresponding voltage to the conductive layers 204 and 212) to drive the liquid crystal layer (e.g., liquid crystal layer 208) to achieve the transmission rate and reflectivity adjustment.
In one embodiment, the dimming device drive system 700 is electrically coupled to the interior and/or exterior rearview dimmable mirror, to control a level of dimming in response to sensed light intensity. In one embodiment, the dimming device drive system 700 is electrically coupled to the interior and/or exterior rearview dimmable mirror, to drive the streaming media display. While the dimmable mirror apparatus 200 is shown here, the drive circuitry system 700 may provide signals to other embodiments of dimmable mirror devices, such as those including a display, not including a display, those utilizing linearly polarized light, circularly polarized light, and other variations.
It will be apparent to those skilled in the art that substantial variations may be made in accordance with specific requirements. For example, customized hardware might also be used, and/or particular elements might be implemented in hardware, software (including portable software, such as applets, etc.), or both. Further, connection to other computing devices such as network input/output devices may be employed.
With reference to the appended figures, components that can include memory can include non-transitory machine-readable media. The term “machine-readable medium” and “computer-readable medium” as used herein, refer to any storage medium that participates in providing data that causes a machine to operate in a specific fashion. In embodiments provided hereinabove, various machine-readable media might be involved in providing instructions/code to processing units and/or other device(s) for execution. Additionally or alternatively, the machine-readable media might be used to store and/or carry such instructions/code. In many implementations, a computer-readable medium is a physical and/or tangible storage medium. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Common forms of computer-readable media include, for example, magnetic and/or optical media, any other physical medium with patterns of holes, a RAM, a programmable ROM (PROM), erasable PROM (EPROM), a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read instructions and/or code.
The methods, systems, and devices discussed herein are examples. Various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. The various components of the figures provided herein can be embodied in hardware and/or software. Also, technology evolves and, thus, many of the elements are examples that do not limit the scope of the disclosure to those specific examples.
It has proven convenient at times, principally for reasons of common usage, to refer to such signals as bits, information, values, elements, symbols, characters, variables, terms, numbers, numerals, or the like. It should be understood, however, that all of these or similar terms are to be associated with appropriate physical quantities and are merely convenient labels. Unless specifically stated otherwise, as is apparent from the discussion above, it is appreciated that throughout this Specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” “ascertaining,” “identifying,” “associating,” “measuring,” “performing,” or the like refer to actions or processes of a specific apparatus, such as a special purpose computer or a similar special purpose electronic computing device. In the context of this Specification, therefore, a special purpose computer or a similar special purpose electronic computing device or system is capable of manipulating or transforming signals, typically represented as physical electronic, electrical, or magnetic quantities within memories, registers, or other information storage devices, transmission devices, or display devices of the special purpose computer or similar special purpose electronic computing device or system.
Terms, “and” and “or” as used herein, may include a variety of meanings that also is expected to depend at least in part upon the context in which such terms are used. Typically, “or” if used to associate a list, such as A, B, or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B, or C, here used in the exclusive sense. In addition, the term “one or more” as used herein may be used to describe any feature, structure, or characteristic in the singular or may be used to describe some combination of features, structures, or characteristics. However, it should be noted that this is merely an illustrative example and claimed subject matter is not limited to this example. Furthermore, the term “at least one of” if used to associate a list, such as A, B, or C, can be interpreted to mean any combination of A, B, and/or C, such as A, AB, AA, AAB, AABBCCC, etc.
Having described several embodiments, various modifications, alternative constructions, and equivalents may be used without departing from the scope of the disclosure as defined by the appended claims. For example, the above elements may merely be a component of a larger system, wherein other rules may take precedence over or otherwise modify the application of the various embodiments. Also, a number of steps may be undertaken before, during, or after the above elements are considered. Accordingly, the above description does not limit the scope of the disclosure.
| Number | Date | Country | |
|---|---|---|---|
| 63162325 | Mar 2021 | US |
