CN117826475A - Electronic rearview mirror with display function - Google Patents
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- CN117826475A CN117826475A CN202410240100.5A CN202410240100A CN117826475A CN 117826475 A CN117826475 A CN 117826475A CN 202410240100 A CN202410240100 A CN 202410240100A CN 117826475 A CN117826475 A CN 117826475A
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Abstract
The invention relates to an electronic rearview mirror with a display function, which comprises a display and an electronic control reflecting mirror arranged at the front side of the display; the electric control reflector comprises a mirror surface layer and a liquid crystal light control piece arranged on the front side of the mirror surface layer; the mirror layer is a semi-transparent reflecting film and is a multilayer optical film formed by overlapping a plurality of layers of optical medium films with high and low refractive indexes; the liquid crystal light control piece comprises a liquid crystal box and a first polaroid arranged on the front side of the liquid crystal box, and the first polaroid is provided with a first polarizing axis; the liquid crystal box adopts a vertical alignment liquid crystal box, the optical path difference of the liquid crystal layer is at least lambda/4, and the liquid crystal layer has an alignment axis which is at a first half right angle with the first polarizing axis; the liquid crystal box is provided with the first optical film, and the first optical film is a compensation film with a vertical fast axis, so that the electronic rearview mirror has consistent and high reflectivity and transmittance at all parts of the electronic rearview mirror, uneven brightness of a display picture can be avoided, the visual angle characteristic of the electronic rearview mirror can be effectively improved, the manufacturing cost is lower, and the electronic rearview mirror is easy to popularize and apply.
Description
Technical Field
The invention relates to the field of automobile rearview mirrors, in particular to an electronic rearview mirror with a display function.
Background
The electronic rearview mirror with the display function generally has the functions of preventing high beam and displaying images, and has become the first choice of intelligent automobiles. The electronic rearview mirror generally comprises an electronic control reflecting mirror and a display, wherein the electronic control reflecting mirror generally comprises a mirror surface layer, the far-reaching light prevention function of the electronic control reflecting mirror can be realized through a liquid crystal light control part (such as a liquid crystal light valve) arranged on the front side of the mirror surface layer, and when an automobile senses that a far-reaching light irradiates behind the automobile, the liquid crystal light control part can quickly reduce the reflectivity of the electronic control reflecting mirror so as to reduce the visual interference of lamplight to a driver and improve the driving safety.
The mirror surface layer of the electric control reflector needs to have double-layer functions of mirror surface reflection and picture transmission, a polarized light reflecting film is generally adopted at present, the polarized light reflecting film is a reflecting film with vertical polarization of reflected light and transmitted light, and only 3M company can provide the polarized light at present globally, the polarized light reflecting film is high in price and cannot be produced autonomously in China, so that popularization and application of the electronic rearview mirror are limited.
Disclosure of Invention
The invention aims to solve the technical problem of providing the electronic rearview mirror with the display function, which not only can ensure that the electronic rearview mirror has consistent and higher reflectivity and transmittance at all parts, can avoid uneven brightness of a display picture, but also can effectively improve the visual angle characteristic of the electronic rearview mirror, has lower manufacturing cost and is easy to popularize and apply. The technical scheme adopted is as follows:
an electronic rearview mirror with a display function comprises a display and an electronic control reflecting mirror arranged on the front side of the display; the electronic control reflector comprises a mirror layer and a liquid crystal light control piece, wherein the liquid crystal light control piece is arranged on the front side of the mirror layer and is used for controlling the reflection state of the electronic control reflector; the method is characterized in that: the mirror layer is a semi-transparent reflecting film and is a multilayer optical film formed by overlapping a plurality of layers of optical medium films with high and low refractive indexes; the liquid crystal light control piece comprises a liquid crystal box and a first polaroid arranged on the front side of the liquid crystal box, and the first polaroid is provided with a first polarizing axis; the liquid crystal box adopts a vertical alignment liquid crystal box, the optical path difference of the liquid crystal layer is at least lambda/4, and the liquid crystal layer has an orientation axis which is at a first half right angle with the first polarization axis; the liquid crystal box is provided with a first optical film which is a compensation film with a vertical fast axis.
The display may be a liquid crystal display, an organic light emitting display, an LED display, or the like. The display may be a monochrome display or a color display. The display may be a pen segment display for displaying simple patterns, or may be a dot matrix display, especially a high definition dot matrix display (e.g., a high definition TFT display). The display can be combined with the electric control reflector in a mode of structural fixation, frame pasting or full pasting and the like.
The mirror layer is a semi-transparent reflective film, which is a multilayer optical film formed by overlapping a plurality of optical medium films with high and low refractive indexes, for example: the refractive index of the high refractive index dielectric film is 1.8-2.7, and the specific film material can be TiO 2 、Ti 3 O 5 、Nb 2 O 5 、Ta 2 O 5 A thin film; folding of low refractive index dielectric filmThe emissivity is 1.3-1.6, and the specific film material can be MgF 2 、SiO 2 The thin films, the multilayer optical film, have more uniform reflectivity and transmittance throughout than the metal film, thereby avoiding uneven brightness of the display screen. The mirror layer can be arranged on an independent transparent plate (such as a glass plate) and then combined with the liquid crystal light control piece; the mirror layer can also be combined with the liquid crystal light control member by means of structural fixation, frame attachment or full attachment (preferred) and the like. In one embodiment, the mirror layer is disposed on a rear side of the liquid crystal light control member.
The vertical alignment liquid crystal box is a liquid crystal box in a vertical alignment mode, specifically, the vertical alignment liquid crystal box comprises a first transparent plate, a second transparent plate (such as a glass substrate) and a liquid crystal layer, wherein the liquid crystal layer is sandwiched between the first transparent plate and the second transparent plate and is composed of negative liquid crystal (nematic liquid crystal, the liquid crystal molecules tend to be vertical to an electric field when being acted by the electric field), a first transparent electrode (such as an ITO electrode) and a first alignment layer are arranged on the side surface of the first transparent plate, which is close to the liquid crystal layer, and a second transparent electrode (such as an ITO electrode) and a second alignment layer are arranged on the side surface of the second transparent plate, which is close to the liquid crystal layer, and the first alignment layer and the second alignment layer are vertical alignment layers, so that the liquid crystal molecules in the liquid crystal layer are in a natural state to be vertical alignment. The optical path difference of the liquid crystal layer is the product Deltan×d of the thickness d of the liquid crystal layer and the birefringence Deltan of the liquid crystal, which can be set to be 1.2-3 times of lambda/4 or 140-400 nm. The alignment axis is obtained by applying alignment friction to the alignment layers at an axial angle, and specifically, it may apply alignment friction to the first alignment layer or the second alignment layer, or simultaneously apply alignment friction coaxially opposite to the first alignment layer and the second alignment layer, so that the liquid crystal molecules have a slight pretilt angle (pretilt angle is not more than 5 °, and may still be considered as vertical alignment) in the axial direction.
In particular, the first optical film may be attached to the front side (the first optical film is between the first polarizer and the liquid crystal cell) or the back side (the first optical film is between the liquid crystal cell and the mirror layer) of the liquid crystal cell, and the compensation film having a vertical fast axis is generally referred to as C - -plate compensation film, compensation amount thereofCan be designed to be close to or equal to the optical path difference of the liquid crystal layer, for example, 0.6 to 1.4 times of the optical path difference of the liquid crystal layer. By arranging the first optical film, the retardation of the light at the oblique viewing angle is reduced or eliminated in the high reflection state by the compensation of the compensation film, so that the polarization state of the reflected light at the oblique viewing angle is less or even unchanged, and the reflectivity is maintained, thereby improving the viewing angle characteristics of the electronic rearview mirror.
The liquid crystal light control piece is used for controlling the reflection state of the electric control reflecting mirror, and the electric control reflecting mirror can be controlled to be in a high reflection state or a low reflection state through driving voltage. When no voltage is applied to the first transparent electrode and the second transparent electrode of the liquid crystal box (or the voltage is smaller than the threshold voltage), the optical retardation of the liquid crystal layer is almost zero (at least in the vertical viewing angle), external light is converted into a linear polarizer by the first polarizer after entering the liquid crystal light control piece through the first polarizer, the polarization state of the liquid crystal light is not changed in the whole process of passing through the liquid crystal layer, being reflected by the mirror surface layer and passing through the liquid crystal layer again, and finally the liquid crystal light is not absorbed when exiting through the first polarizer, so that the electronically controlled reflector is in a high reflection state; when a voltage exceeding a threshold value is applied to the first transparent electrode and the second transparent electrode of the liquid crystal box, liquid crystal molecules of the liquid crystal layer are further deflected and inclined along the axial direction to enable the liquid crystal layer to display optical delay, the delay amount can reach lambda/4 through voltage control, external light is firstly converted into linear polarization by the first polarizer after entering the liquid crystal light control piece through the first polarizer, then is converted into circular polarization by the liquid crystal layer of the liquid crystal box, the circular polarization is converted into circular polarization with the other rotation direction (such as left rotation is changed into right rotation and right rotation is changed into left rotation) after being reflected by the mirror surface layer, and is converted into another linear polarization perpendicular to the polarization angle of the original linear polarization when passing through the liquid crystal layer again, and finally is absorbed by the first polarizer and cannot be emitted, so that the electric control reflector is in a low reflection state. The electronic rearview mirror adopts the liquid crystal light control piece to control light, and the liquid crystal layer is switched between a high reflection state and a low reflection state by applying voltage or not, because the liquid crystal light control piece is only provided with the first polaroid, the loss of light is less, the liquid crystal light control piece has higher reflectivity in the high reflection state, the reflectivity loss of the mirror surface layer can be compensated, and in the low reflection state, external incident light cannot be transmitted out of the light output of the interference display, so that the overall transmittance of the electronic rearview mirror is improved, an expensive polarized light reflecting film is not needed, the manufacturing cost is lower, and the popularization and the application are easy.
As a preferred embodiment of the invention, the reflectivity of the mirror layer is at least 80%. The reflectivity of the electronically controlled mirror can be improved, and the display screen of the display has only about 20% transmittance, but can be ensured by improving the backlight brightness.
As a preferable scheme of the invention, the electronic rearview mirror further comprises a controller capable of controlling the electronic rearview mirror to be in a low reflection state or a high reflection state, and the controller is in linkage with the display; when the display displays a picture, the controller controls the electronically controlled mirror to be in a low reflection state. When the liquid crystal light control piece is in a low reflection state, the liquid crystal light control piece still has higher transmittance for the light emitted by the rear display passing through the lens surface layer, and when the display displays a picture, the controller controls the electric control reflector to be in the low reflection state, so that the situation that a reflected scene is overlapped with the display picture to reduce the watching experience can be avoided.
As a preferred embodiment of the present invention, the electronic rear view mirror further includes a second polarizer disposed on a front side of the display, the second polarizer having a second polarizing axis, and a second optical film; the second optical film is arranged between the second polaroid and the mirror surface layer, the second optical film is a retardation film with a horizontal optical axis and a retardation of lambda/4 or-lambda/4, and the horizontal optical axis of the second optical film and the second polarizing axis form a second half right angle. Typically, the display is a liquid crystal display and the second polarizer is its front polarizer. Therefore, the light emitted from the display can be converted into circular polarized light by the second optical film, when the second half right angle is set to be a proper positive angle or negative angle (in a specific scheme, the second half right angle can be set to be +45° or-45 ° according to the positive and negative of the first half right angle, so as to achieve the required optical effect), and when the electronically controlled reflector is controlled to be in a low reflection state, the circular polarized light of the light emitted from the display is opposite to the reflection light of the mirror surface layer, the reflection light of the mirror surface layer cannot be emitted, and the transmittance of the light emitted from the display is higher, so that the display brightness can be further improved. In addition, when the mirror layer is formed by overlapping multiple layers of optical medium films with high and low refractive indexes, the light emitted by the display is converted into circular polarized light by the second optical film, the P light component and the S light component of the circular polarized light are consistent in each inclined view angle for each optical film interface in the mirror layer, and the transmittance of the circular polarized light is consistent in each view angle, so that the problem of view angle caused by polarized light (namely, the transmittance of different view angles is inconsistent) can be avoided, and the display of the rearview mirror has better view angle characteristics.
As a preferable scheme of the invention, the first polarizer is a high-transmittance polarizer with a transmittance of more than 55%. High-transmittance polarizers, i.e., polarizers with less absorption (< 45%) and higher transmission (> 55%). Because the electronically controlled reflector is only provided with the first polaroid, the first polaroid adopts the high-transmittance polaroid, so that the absorption of light rays can be further reduced, and the reflectivity of the high-reflectivity state is higher (at the cost of higher reflectivity of low reflectivity).
In the present specification, the "horizontal plane" refers to a plane parallel to the mirror surface of the mirror, and each angle and axis refer to an angle and axis projected into the horizontal plane, and "vertical" refers to a direction perpendicular to the mirror surface of the mirror, and "vertical viewing angle" refers to a viewing angle of the mirror from the front surface of the mirror, unless otherwise specified. The front side of the mirror and its constituent parts refers to its side relatively close to the user and the rear side refers to its other side relatively far from the user. The upper, lower, left, and right sides refer to the rear view mirror installed in the vehicle and being swung, respectively, the upper, lower, left, and right sides thereof, the upper, lower, left, and right viewing angles refer to the respective viewing angles of the rear view mirror, respectively, from the front of the upper, lower, left, and right sides thereof, which are also collectively referred to as tilting viewing angles, and when the user views the view or display image of the rear view mirror, and the optimal viewing angle thereof is not the vertical viewing angle, the "normal viewing angle" refers to the tilting viewing angle having the optimal viewing effect, and the "reverse viewing angle" refers to the tilting viewing angle having the worst viewing effect.
In the present description, the first half right angle, the second half right angle, in strict or preferred cases, refer to an angle having an absolute value of 45 °, whereas in non-strict cases, the first half right angle, the second half right angle may also refer to an angle having an absolute value close to 45 °, such as in the range of 40 to 50 °.
In this specification, lambda/4 refers to a quarter of the central wavelength of visible light, such as 137nm.
Compared with the prior art, the invention has the following advantages:
(1) The electronic rearview mirror adopts the liquid crystal light control piece to control light, and the liquid crystal layer is switched between a high reflection state and a low reflection state by applying voltage or not, because the liquid crystal light control piece is only provided with the first polaroid, the loss of light is less, the liquid crystal light control piece has higher reflectivity in the high reflection state, the reflectivity loss of a mirror surface layer can be compensated, and in the low reflection state, external incident light cannot be transmitted out of the light outlet of the interference display, so that the overall transmittance of the electronic rearview mirror is improved, a polarized light reflection film is not needed, the manufacturing cost is lower, and the electronic rearview mirror is easy to popularize and apply;
(2) The electronic rearview mirror adopts the semi-transparent reflecting film as a mirror surface layer, and is a multilayer optical film formed by overlapping a plurality of layers of optical medium films with high and low refractive indexes, wherein the multilayer optical film has more uniform reflectivity and transmittance everywhere compared with a metal film, so that uneven brightness of a display picture can be avoided;
(3) By arranging the first optical film and compensating the first optical film, the retardation of light rays at the inclined view angle is reduced or eliminated in a high reflection state, so that the polarization state of reflected light at the inclined view angle is less changed or even unchanged, the reflectivity is maintained, and the view angle characteristic of the rearview mirror can be improved.
Drawings
Fig. 1 is a schematic view of an electronic rear view mirror according to a first preferred embodiment of the present invention.
Fig. 2 is a schematic view of the exterior of the electronic rear view mirror shown in fig. 1.
Fig. 3 is a schematic diagram of the operation of the lcd according to the first preferred embodiment of the present invention.
Fig. 4 is a schematic view of the optical principle of the electrically controlled mirror according to the first preferred embodiment of the present invention when the electrically controlled mirror is in a high reflection state.
Fig. 5 is a schematic diagram of the compensation principle of the first optical film for the oblique viewing angle light in the high reflection state according to the first preferred embodiment of the present invention.
Fig. 6 is a schematic view of the optical principle of the electronic rear view mirror according to the first preferred embodiment of the present invention when the electronically controlled mirror is in a low reflection state.
Fig. 7 is a schematic view of the optical principle of the electronic rear view mirror according to the second preferred embodiment of the present invention when the electronically controlled mirror is in a low reflection state without the second optical film.
Detailed Description
Example 1
As shown in fig. 1 to 6, the electronic rearview mirror with the display function comprises a display 1 and an electronically controlled reflecting mirror 2 arranged on the front side of the display 1; the electronically controlled reflector 2 comprises a mirror layer 21 and a liquid crystal light control piece 22, wherein the liquid crystal light control piece 22 is arranged on the front side of the mirror layer 21, and the liquid crystal light control piece 22 is used for controlling the reflection state of the electronically controlled reflector 2; the mirror layer 21 is a semi-transparent reflective film; the liquid crystal light controlling member 22 includes a liquid crystal cell 221 and a first polarizer 222 disposed at a front side of the liquid crystal cell 221, the first polarizer 222 having a first polarizing axis 2221; the liquid crystal cell 221 employs a vertically aligned liquid crystal cell (i.e., a vertically aligned mode liquid crystal cell), whose optical path difference of the liquid crystal layer 2213 is at least λ/4, and whose liquid crystal layer 2213 has an orientation axis 22131 at a first half right angle to the first polarization axis 2221.
In this embodiment, the liquid crystal cell 221 includes a first transparent plate 2211, a second transparent plate 2212 (e.g. a glass substrate), and a liquid crystal layer 2213, the liquid crystal layer 2213 is sandwiched between the first transparent plate 2211 and the second transparent plate 2212, and is composed of negative liquid crystal (nematic liquid crystal whose liquid crystal molecules tend to be perpendicular to the electric field when the liquid crystal molecules are acted on by the electric field), a first transparent electrode 2214 (e.g. an ITO electrode) and a first alignment layer 2215 are disposed on a side surface of the first transparent plate 2211 near the liquid crystal layer 2213, a second transparent electrode 2216 (e.g. an ITO electrode) and a second alignment layer 2217 are disposed on a side surface of the second transparent plate 2212 near the liquid crystal layer 2213, and the first alignment layer 2215 and the second alignment layer 2217 are vertical alignment layers, so that the liquid crystal molecules in the liquid crystal layer 2213 are in a natural state. The optical path difference of the liquid crystal layer 2213 is the product Δn×d of the thickness d of the liquid crystal layer 2213 and the birefringence Δn of the liquid crystal, which can be generally set to 1.2-3 times of λ/4 or 140-400 nm. The alignment axis 22131 is obtained by applying alignment friction to the alignment layers at an axial angle, and specifically, it may apply alignment friction to the first alignment layer 2215 or the second alignment layer 2217, or simultaneously apply alignment friction coaxially opposite to the first alignment layer 2215 and the second alignment layer 2217, so that the liquid crystal molecules have a slight pretilt angle (pretilt angle is not more than 5 °, and may be regarded as vertical alignment) in the axial direction.
In this embodiment, the mirror layer 21 is disposed on the rear side of the lcd 22, and the mirror layer 21 is a transflective film, which may be a thin metal film (such as an aluminum film or a silver film) with a certain transmittance, or a multilayer optical film formed by overlapping multiple layers of optical dielectric films with high and low refractive indexes, for example: the refractive index of the high refractive index dielectric film is 1.8-2.7, and the specific film material can be TiO 2 、Ti 3 O 5 、Nb 2 O 5 、Ta 2 O 5 A thin film; the refractive index of the low refractive index dielectric film is 1.3-1.6, and the specific film material can be MgF 2 、SiO 2 And the like. The mirror layer 21 may be disposed on a separate transparent plate (e.g., a glass plate) and then combined with the lc light management element 22; the mirror layer 21 may also be combined with the lc light management element 22 by means of structural fastening, frame attachment or full attachment (preferred).
In this embodiment, the display 1 may be combined with the electronically controlled mirror 2 by means of structural fixing, frame attaching or full attaching.
In this embodiment, the reflectivity of the mirror layer 21 is at least 80%. The reflectivity of the galvanometer mirror 2 can be increased, and the display screen of the display 1 has only about 20% transmittance, but can be ensured by increasing the backlight brightness.
In the present embodiment, the liquid crystal cell 221 is provided with a first optical film 223, and the first optical film 223 is a compensation film having a vertical fast axis 2231. Compensation film with vertical fast axis 2231 is generally referred to as C - -a plate compensation film, the compensation amount of which can be designed asThe optical path difference is close to or equal to that of the liquid crystal layer 2213, for example, 0.6 to 1.4 times the optical path difference of the liquid crystal layer 2213. By providing the first optical film 223, the retardation of the light at the oblique viewing angle is reduced or eliminated in the high reflection state by the compensation of the compensation film, so that the polarization state of the reflected light at the oblique viewing angle is less changed or even unchanged, and thus the reflectivity is maintained, whereby the viewing angle characteristics of the rear view mirror can be improved.
In this embodiment, the electronic rearview mirror further includes a controller 3 capable of controlling the electronically controlled mirror 2 to be in a low reflection state or a high reflection state, and the controller 3 is in linkage with the display 1; when the display 1 displays a picture, the controller 3 controls the electronically controlled mirror 2 to a low reflection state. When the liquid crystal light control member 22 is in a low reflection state, the liquid crystal light control member has higher transmittance for the light emitted by the rear display 1 passing through the lens surface layer 21, and when the display 1 displays a picture, the controller 3 controls the electric control reflector 2 to be in a low reflection state, so that the situation that a reflected scene overlaps the display picture and the viewing experience is reduced can be avoided.
In this embodiment, the electronic rear view mirror further comprises a second polarizer 4 and a second optical film 5, the second polarizer 4 being disposed on the front side of the display 1, the second polarizer 4 having a second polarizing axis 41; the second optical film 5 is disposed between the second polarizer 4 and the mirror layer 21, the second optical film 5 being a retardation film having a horizontal optical axis 51 and a retardation of λ/4 or- λ/4, the horizontal optical axis 51 of the second optical film 5 being at a second half right angle to the second polarizing axis 41. The display 1 is a liquid crystal display and the second polarizer 4 is its front polarizer. Thus, the light emitted from the display 1 can be converted into circular polarized light by the second optical film 5, when the second half right angle is set to a suitable positive angle or negative angle (in a specific scheme, the optical axis of the second optical film 5 can be a fast axis or a slow axis, and the positive and negative of the first half right angle, the second half right angle is set to +45° or-45 ° to achieve the required optical effect, and when the electronically controlled mirror 2 is controlled to be in a low reflection state, the rotation direction of the circular polarized light emitted from the display 1 is opposite to the reflection light of the mirror layer 21, and the reflection light of the mirror layer 21 cannot be emitted, but the transmittance of the light emitted from the display 1 is higher, so that the display brightness can be further improved. In addition, when the mirror layer 21 is formed by overlapping multiple layers of optical medium films with high and low refractive indexes, the light emitted from the display 1 is converted into circular polarized light by the second optical film 5, and for each optical film interface inside the mirror layer 21, P light and S light components of the circular polarized light are consistent at each oblique viewing angle, and the transmittance of the circular polarized light is consistent at each viewing angle, so that the problem of viewing angle caused by polarized light (that is, the transmittance of different viewing angles is inconsistent) can be avoided, and the display of the rearview mirror has better viewing angle characteristics.
The working principle of the electronic rearview mirror is briefly described below:
the lc light controlling element 22 is configured to control the reflection state of the electronically controlled mirror 2, and can control the electronically controlled mirror 2 to be in a high reflection state or a low reflection state by a driving voltage.
When no voltage is applied to the first transparent electrode 2214 and the second transparent electrode 2216 of the liquid crystal cell 221 (or the voltage is smaller than the threshold voltage), the optical retardation of the liquid crystal layer 2213 is almost zero (at least in the vertical viewing angle), after the external light enters the liquid crystal light control member 22 through the first polarizer 222, the external light is converted into a linear polarizer by the first polarizer 222, the polarization state of the external light is not changed in the whole process of passing through the liquid crystal layer 2213, reflecting through the mirror layer 21 and passing through the liquid crystal layer 2213 again, and finally the external light is not absorbed when exiting through the first polarizer 222, so that the electronically controlled mirror 2 presents a high reflection state; when a voltage exceeding a threshold value is applied to the first transparent electrode 2214 and the second transparent electrode 2216 of the liquid crystal cell 221, the liquid crystal molecules of the liquid crystal layer 2213 deflect and tilt further along the axial direction to make the liquid crystal layer 2213 show an optical retardation, the retardation can reach λ/4 through voltage control, external light is firstly converted into linear polarization by the first polarizer 222 after entering the liquid crystal light control member 22 through the first polarizer 222, then is converted into circular polarization by the liquid crystal layer 2213 of the liquid crystal cell 221, and is converted into circular polarization with another rotation direction (such as that the left rotation is changed into the right rotation and the right rotation is changed into the left rotation) after being reflected by the mirror layer 21, and is converted into another linear polarization perpendicular to the polarization angle of the original linear polarization when passing through the liquid crystal layer 2213 again, and finally is absorbed by the first polarizer 222 without being emitted, thereby making the electronically controlled mirror 2 show a low reflection state.
Example 2
Referring to fig. 7, in the case where the other portions are the same as in the first embodiment, the difference is that: in the present embodiment, the first polarizer 222 is a high-transmittance polarizer having a transmittance of 55% or more, and the second optical film 5 is not disposed between the second polarizer 4 and the mirror layer 21. High-transmittance polarizers, i.e., polarizers with less absorption (< 45%) and higher transmission (> 55%). Since the electronically controlled reflector 2 is only provided with the first polarizer 222, the first polarizer 222 is a high-transmittance polarizer, which can further reduce light absorption, so that the reflectivity of the high-reflectivity state is higher (at the cost of low-reflectivity). After the second optical film 5 is removed, the display screen still has a certain transmittance.
In addition, it should be noted that, in the specific embodiments described in the present specification, names of various parts and the like may be different, and all equivalent or simple changes of the structures, features and principles described in the conception of the present invention are included in the protection scope of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions in a similar manner without departing from the scope of the invention as defined in the accompanying claims.
Claims (6)
1. An electronic rearview mirror with a display function comprises a display and an electronic control reflecting mirror arranged on the front side of the display; the electronic control reflector comprises a mirror layer and a liquid crystal light control piece, wherein the liquid crystal light control piece is arranged on the front side of the mirror layer and is used for controlling the reflection state of the electronic control reflector; the method is characterized in that: the mirror layer is a semi-transparent reflecting film and is a multilayer optical film formed by overlapping a plurality of layers of optical medium films with high and low refractive indexes; the liquid crystal light control piece comprises a liquid crystal box and a first polaroid arranged on the front side of the liquid crystal box, and the first polaroid is provided with a first polarizing axis; the liquid crystal box adopts a vertical alignment liquid crystal box, the optical path difference of the liquid crystal layer is at least lambda/4, and the liquid crystal layer has an orientation axis which is at a first half right angle with the first polarization axis; the liquid crystal box is provided with a first optical film which is a compensation film with a vertical fast axis.
2. An electronic rearview mirror with a display function according to claim 1, characterized in that: the mirror layer is arranged on the rear side face of the liquid crystal light control piece.
3. An electronic rearview mirror with a display function according to claim 1, characterized in that: the mirror layer has a reflectivity of at least 80%.
4. An electronic rearview mirror with a display function according to claim 1, characterized in that: the first polaroid is a high-transmittance polaroid with transmittance of more than 55%.
5. An electronic rear view mirror with display function according to any of claims 1-4, characterized in that: the electronic rearview mirror further comprises a controller capable of controlling the electronic control reflecting mirror to be in a low reflection state or a high reflection state, and the controller is in linkage with the display; when the display displays a picture, the controller controls the electronically controlled mirror to be in a low reflection state.
6. An electronic rear view mirror with display function according to any of claims 1-4, characterized in that: the electronic rearview mirror further comprises a second polaroid and a second optical film, the second polaroid is arranged on the front side surface of the display, and the second polaroid is provided with a second polarizing axis; the second optical film is arranged between the second polaroid and the mirror surface layer, the second optical film is a retardation film with a horizontal optical axis and a retardation of lambda/4 or-lambda/4, and the horizontal optical axis of the second optical film and the second polarizing axis form a second half right angle.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410240100.5A CN117826475A (en) | 2024-03-04 | 2024-03-04 | Electronic rearview mirror with display function |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410240100.5A CN117826475A (en) | 2024-03-04 | 2024-03-04 | Electronic rearview mirror with display function |
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| CN117826475A true CN117826475A (en) | 2024-04-05 |
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| CN202410240100.5A Pending CN117826475A (en) | 2024-03-04 | 2024-03-04 | Electronic rearview mirror with display function |
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| CN117471749A (en) * | 2022-07-28 | 2024-01-30 | 中强光电股份有限公司 | Electric control optical screen |
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| JP2000321426A (en) * | 1999-05-12 | 2000-11-24 | Nitto Denko Corp | Wide visual field angle polarizing plate and liquid crystal display device |
| CN1608218A (en) * | 2001-11-19 | 2005-04-20 | 新日本石油株式会社 | Circular polarizing plate and liquid crystal display device |
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