KR101189323B1 - LCD mirror apparatus - Google Patents

Abstract

An LCD mirror device is provided that protects the driver's eyesight and prevents glare from the strong headlights emitted by the rear vehicle when driving at night. The LCD mirror device is an LCD mirror device for preventing glare of the driver of the vehicle by the light incident from the rear, and is installed in the vehicle, and the light transmittance is changed according to the magnitude of the LCD driving voltage applied to the mirror to reflect the reflection mirror. An LCD mirror to adjust the amount of light reaching the driver; An optical sensor including a rear optical sensor that detects light incident on the LCD mirror at the rear of the vehicle and outputs an analog signal, and a front optical sensor which detects light incident from the driver's vicinity and outputs an analog signal; Receives analog signals output from the front and rear light sensors, and changes the sensitivity of the light quantity detected by the front and rear light sensors respectively, and compares the sensitivity of the variable light quantity to compare the front and rear light sensors. An LCD mirror driver configured to determine an LCD driving voltage corresponding to a brightness difference value between the rear incident light and the ambient incident light detected by and to apply the determined LCD driving voltage to the LCD panel of the LCD mirror; And a power supply unit applying direct current and alternating current power to the LCD mirror, the optical sensor, and the LCD mirror driving unit, respectively.

LCD Mirror, Automotive, Light Sensor, Room Mirror, Reflective, ECM, LCD, TN

Description

LCD mirror apparatus {LCD mirror apparatus}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LCD mirror, and more particularly, to protects a driver's eyesight and prevents glare from a strong headlight light emitted from a rear vehicle at night, such as a room mirror or a rear view mirror. The present invention relates to an LCD mirror device using an LCD panel that adjusts the reflectance of a side mirror.

In general, when driving a car, it is very important to secure a view because the driver is driving at a high speed in a closed space.

FIG. 1 is a perspective view illustrating an exterior of a general vehicle. As shown in FIG. 1, a wind shield glass 11 is provided on a front surface of a vehicle 10 to secure a front view, and inside and left and right sides of a vehicle. The rear view is ensured by providing a room mirror 14 and an outside mirror 15 on the outer surfaces of the front pillars 12 and 13, respectively.

Recently, a technology applied to the exterior mirror 15 of the exterior structure of the vehicle is a smart mirror, which is a safety feature by suppressing a glare phenomenon that a driver can feel due to light reflection by a headlight of a rear vehicle. It is for driving. The smart mirror for the vehicle mainly uses ECM (Electro-chromic Material) technology, and related materials are US Patents US4,902,108, US5,204,778, US5,278,693, US5,280,380, US5,282,077, US5,336,448, Known as US5,448,397, US5,451,822, US6,512,624, etc., it is currently commercialized and installed in millions of vehicles each year.

In addition, the US patent US Pat. No. 4,676,601 applies LCDs to automotive electronic mirrors, the main contents of which are limited to the technology of light sensing and operation of the LCD.

Until recently, the production of electronic mirrors for cars is mainly made of products using ECM. ECM room mirrors, which are currently in mass production, have a relatively slow reaction speed of 3 to 6 seconds even at room temperature, and have a relatively large power consumption of several hundreds of megawatts. The ECM used in the electronic mirror induces oxidation reaction and reduction reaction by DC voltage so that it has a colored state and a colorless state, respectively. However, this oxidation and reduction reaction has hysteresis, which makes it very difficult to control the intermediate brightness or gray scale from an optical point of view.

In order to improve the reaction speed of the ECM, a method of accelerating oxidation and reduction reactions by applying a momentary high voltage is used, and sheet resistance of a transparent electrode made of indium thin oxide (ITO) thin film to smooth current flow between both electrodes. In addition, the contact area of the metal electrode connected to the ITO thin film electrode is made as wide as possible.

However, in order to display the intermediate brightness, the response of ECM is slow and the circuit is complicated. Therefore, in the existing ECM mirror, it is difficult to precisely adjust in real time by connecting the degree of glare of the driver detected by the optical sensor with the reflectance change of the ECM mirror.

As described above, the conventional ECM is operated by an electrochemical reaction, so the reaction rate is relatively slow (3 to 6 seconds), which is insufficient to protect the driver's vision. Research on LCD mirrors with LCDs) continues.

On the other hand, as a prior art related to such an LCD mirror, Korean Patent Application No. 2003-80226 (Application Date: November 13, 2003) discloses an invention named "LCD mirror with adjustable reflectivity", It is applied to a room mirror or side mirror, and its light reflectance is adjusted according to the amount of incident light, which reduces the glare of the driver and protects the driver's vision from the strong light from the rear during night driving. It is about. Referring to Figure 2 will be described with respect to the LCD mirror adjustable reflectivity.

2 is a configuration diagram for explaining a method for adjusting the amount of reflected light using the LCD according to the related art.

Referring to FIG. 2, in the reflection light amount adjusting method using the LCD according to the related art, light incident on the mirror is detected by at least one semiconductor light sensor by the incident light detector 21, Detect the light coming separately.

The operation analysis unit 22 analyzes the brightness of the light detected by the optical sensor to determine whether to apply a voltage required for the mirror. In other words, when the light from the rear of the vehicle is strong enough to give a glare to the driver, it is possible to apply enough voltage to the mirror to reduce the light reflectance of the mirror.

When it is determined whether the voltage is applied to the LCD mirror 24 in the operation analysis unit 22, the power supply and the driving unit 23 supply the electrical energy supplied from the battery power to the LCD portion of the mirror to operate the LCD. .

The conventional technique operating as described above is to turn on or off the LCD based on a predetermined threshold value according to the amount of incident light detected through the light sensor, There was a technical limitation that it could not improve the fatigue of the driver's eyes because fine adjustment is not made according to the amount of incident light.

Furthermore, in the case of applying the above-described conventional technology, since the liquid crystal of the LCD provided in the mirror that the driver looks at is generally dark, the mirror located at the rear of the liquid crystal of the LCD does not normally function as a mirror, so the headlamp at night When the vehicle is turned on or only the fog light is approaching from the rear left and right, there was a problem that the driver does not easily recognize the approaching vehicle.

In order to solve the problem of the reflected light amount control method using the LCD, Korean Patent Application No. 2005-98905 (filed date: October 20, 2005) discloses the invention named "LCD mirror light amount fine control device" In order to protect the driver's vision from the strong light from the rear when driving at night, it is possible to finely adjust the reflectance of the vehicle's Room Mirror or Rear View Mirror or Side Mirror in real time. will be. A detailed description with reference to FIG. 3 is as follows.

3 is a block diagram of the LCD mirror fine-tuning device according to the prior art.

Referring to FIG. 3, in the LCD mirror reflected light amount fine adjustment device according to the related art, reference numeral 30 denotes an LCD panel having a dot structure, and the light transmission amount varies according to the magnitude of voltage introduced thereto. In addition, the mirror 31 serves to reflect the light transmitted through the LCD panel 30 to the driver's field of view, and the refraction reflector 32 has the light transmitted through the LCD panel 30 to the mirror 31. When reflecting through a certain amount of light to reflect in a direction different from the driver's field of view.

A lens 33 for collecting light reflected by a refractive reflector 32 in a direction different from the driver's field of view, and a CCD module 34 for recognizing light collected by the lens 33. The light sensing unit is configured.

In addition, the control unit, denoted by reference numerals 35 to 38, includes a light amount detecting unit for generating differential or integrated data of electric signals generated by the CCD modules 34 of the light sensing units 33 and 34 for each period of a predetermined time range ( 35), the database storing reference data for adjusting the amount of reflected light (DB) 36, and comparing the data of the current point detected by the light amount detector 35 based on the data of the DB 36 to adjust the amount of reflected light LCD for adjusting the voltage applied to the LCD panel 30 according to the voltage of the adjustment voltage calculation unit 37 for calculating and outputting the magnitude of the voltage for the output, and the voltage output from the adjustment voltage calculation unit 37 The drive part 38 is comprised.

However, the LCD mirror reflected light amount fine control device according to the prior art, when the vehicle is turned on at night or only the fog light is approaching from the left and right side, to solve the problem that the driver does not easily recognize the approaching vehicle Since only finely adjusts the LCD mirror reflection light amount based on the amount of light detected by the rear light sensor, there is a problem in that it cannot easily cope with environmental changes. That is, the LCD mirror is mainly affected by the amount of light detected by the rear light sensor, but is also affected by the amount of light reflected from the driver's surroundings. Since it does not consider the amount of light, there is a problem that can not respond to environmental changes, such as day or night.

The technical problem to be solved by the present invention to solve the above problems, the degree of glare of the vehicle driver automatically adjusts the reflectance using the LCD panel, and recognizes the two front and rear silicon photo sensor (Si Photo-diode) An object of the present invention is to provide an LCD mirror device capable of driving in a continuous gray scale method by reflecting one brightness difference on an LCD panel.

In addition, another technical problem to be achieved by the present invention is to provide an LCD mirror device that can distinguish between day and night sensitivity by varying the sensitivity of the front light sensor using a switching element based on a constant brightness.

In addition, another technical problem to be achieved by the present invention is to provide an LCD mirror device that can be optimized by adapting to environmental changes by varying the rate of change of the current generated from the front and rear light sensor.

As a means for achieving the above technical problem, the LCD mirror device according to the present invention, in the LCD (Liquid Crystal Display) mirror device for preventing the glare of the vehicle driver by the light incident from the rear, is installed in the vehicle An LCD mirror that adjusts the amount of light that is transmitted from the reflective mirror to the driver by varying light transmittance according to the magnitude of the LCD driving voltage applied; An optical sensor including a rear optical sensor that detects light incident on the LCD mirror from the rear of the vehicle and outputs an analog signal, and a front optical sensor which detects light incident from the driver's vicinity and outputs an analog signal; Receives an analog signal output from the front optical sensor and the rear optical sensor, and varies the sensitivity of the light amount respectively detected by the front and rear light sensor, and compares the sensitivity of the variable light amount and the front light sensor An LCD mirror driver configured to determine an LCD driving voltage corresponding to a brightness difference value between the rear incident light and the ambient incident light detected by the rear light sensor, and apply the determined LCD driving voltage to the LCD panel of the LCD mirror; And a power supply unit applying direct current and alternating current power to the LCD mirror, the optical sensor, and the LCD mirror driving unit, respectively.

Here, the optical sensor may include a front optical sensor for recognizing the front or surrounding brightness of the vehicle driver and at least one rear optical sensor for recognizing the brightness incident on the LCD mirror from the headlight of the rear vehicle, the optical sensor May be a silicon semiconductor diode.

Here, the LCD mirror driving unit, a front sensitivity control unit for adjusting the sensitivity of the front optical sensor in response to the analog signal output from the front optical sensor; A rear sensitivity control unit for adjusting the sensitivity of the rear optical sensor in response to an analog signal output from the rear optical sensor; A front / rear sensitivity comparison unit configured to determine a predetermined LCD driving voltage by comparing the front sensitivity and the rear sensitivity of each of which the sensitivity is adjusted; And an AC voltage controller configured to apply the LCD driving voltage determined by the front / rear sensitivity comparing unit to the LCD panel of the LCD mirror.

Here, the front sensitivity control unit and the rear sensitivity control unit is characterized in that for controlling the flow of current generated by the front optical sensor and the rear optical sensor, respectively.

Here, the front sensitivity control unit and the rear sensitivity control unit controls the amount of current and discharge amount to adjust the flow of the generated current, respectively, characterized in that the discharge amount is adjusted to the size of the resistance connected to the ground.

Here, the front sensitivity adjuster and the rear sensitivity adjuster respectively adjust the rate of change of the current flow to adjust the flow of the generated current, the front sensitivity adjuster and the rear sensitivity adjuster and the resistor to adjust the rate of change of the current flow. It is characterized by adjusting the time constant of the RC circuit consisting of a battery.

The front / rear sensitivity comparison unit may set the voltage difference to be less than or equal to the threshold voltage of the LCD panel when the intensity of light incident on the front optical sensor is large enough to be recognized as low.

Here, the front / rear sensitivity comparison unit is characterized by recognizing the difference between the current or voltage generated in the front sensitivity control unit and the rear sensitivity control unit.

Here, when the current or voltage of the front sensitivity control unit has a value larger than the current or voltage of the rear sensitivity control unit, the front / rear sensitivity comparison unit sets the difference value to zero.

Here, the AC voltage adjusting unit converts the current or DC voltage difference determined by the front / rear sensitivity comparing unit into an AC voltage level, and supplies the same to the LCD panel of the LCD mirror.

Here, the LCD panel of the LCD mirror may be configured as an LCD of the TN mode, ECB mode, or VA mode.

Here, the power supply unit may include a DC power source and an AC power source, and the DC power source may be a power source of a vehicle, a primary battery, a secondary battery, or a solar cell.

According to the present invention, the degree of glare of the driver detected by the semiconductor optical sensor can be reflected in the light reflectance of the electronic LCD mirror in real time.

According to the present invention, when driving the electronic mirror with the difference in brightness recognition between the front sensor and the rear sensor, the malfunction of the electronic LCD mirror can be minimized by varying the sensitivity and response speed of each optical sensor. .

According to the present invention, the light reflectance and the response speed of the electronic LCD mirror can be arbitrarily selected according to the change in the brightness of the surroundings by using the fast response speed and the halftone of the LCD, thereby minimizing the glare of the driver.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

As an embodiment of the present invention, by using the LCD panel with fast response speed and easy display of gray scales, the reflectance can be automatically reduced to reduce the glare of the vehicle driver, and the brightness difference recognized by the front and rear light sensors. There is provided an LCD mirror device that can reflect the reflection on the LCD panel.

4 is a block diagram of an LCD mirror device according to an embodiment of the present invention.

Referring to FIG. 4, the LCD mirror apparatus 100 according to the embodiment of the present invention includes an optical sensor 110, an LCD mirror driver 120, an LCD mirror 130, and a power supply 140.

LCD mirror apparatus 100 according to an embodiment of the present invention, the brightness of the front and rear of the vehicle respectively sensed by the front light sensor 111 and the rear light sensor 112 is converted into a current magnitude, respectively, the light sensitivity control unit After the reaction time and the sensitivity is adjusted at (121, 122) is converted into current or voltage, and the front and rear sensitivity comparison unit 123, the brightness difference between the front and rear is converted into a relative DC voltage difference after the AC voltage control unit At 124, the voltage is converted into the magnitude of the alternating voltage and finally applied to the LCD panel of the LCD mirror 130. In this case, the power supply unit 140 applies DC and AC power to the LCD mirror 130, the optical sensor 110, and the LCD mirror driver 120, respectively.

In detail, the optical sensor 110 is a silicon photo sensor, and includes a front photo sensor 111 and a rear photo sensor 112, wherein the front photo sensor 111 is located at the front of the vehicle. It is mounted to detect the amount of light in front of the vehicle, the rear light sensor 112 is mounted on the rear of the vehicle to detect the amount of light behind the vehicle. Typically, the LCD mirror causes the driver to feel glare according to the amount of light behind the vehicle, but is also affected by the amount of light around the driver in front of the vehicle due to changes in the environment during the day or night.

The LCD mirror driver 120 receives analog signals output from the front optical sensor 111 and the rear optical sensor 112, respectively, and the amount of light detected by the front optical sensor 111 and the rear optical sensor 112, respectively. The sensitivity of the light source is compared to generate the LCD driving voltage by comparing the sensitivity of the variable light amount, and outputs the LCD mirror driving signal of the continuous gray scale type according to the LCD driving voltage. Here, the reason for adjusting the sensitivity of the light amount of the front light sensor 111 and the rear light sensor 112 is mainly due to the LCD mirror affected by the rear light sensor 112 by the front light sensor 111. To reflect the impact.

In addition, the LCD mirror driver 120 may distinguish day / night sensitivity by providing a difference in sensitivity of the front optical sensor 111 using a switching element based on a constant brightness. That is, the LCD mirror is mainly affected by the amount of light detected by the rear light sensor 112, but is also affected by the amount of light detected by the front light sensor 111, so the difference in the sensitivity of the front light sensor 111 is different. By providing, it is possible to cope with environmental changes such as day or night.

The LCD mirror 130 is driven in a continuous gradation manner according to the LCD mirror driving signal. As a result, the LCD mirror 130 displays the brightness difference recognized by the front light sensor 111 and the rear light sensor 112, respectively. Reflectance is automatically adjusted by reflecting on the panel. In addition, the LCD mirror 130 drives the LCD by using an AC voltage having a square waveform. Since the response speed is 0.1 seconds or less, the LCD mirror 130 can react quickly without flicker, and the response characteristics are analog controlled in the circuit itself, so that hysteresis is achieved. There is no need for a digital controller.

Therefore, the LCD mirror apparatus 100 according to the embodiment of the present invention may reduce the glare of the vehicle driver by automatically adjusting the reflectance using the LCD panel having a fast response speed and easy display of halftones, The difference in brightness recognized by the rear light sensor is reflected on the LCD panel, and thus it can be driven in a continuous gray scale method.

5 is a detailed view of the LCD mirror apparatus according to the embodiment of the present invention.

Referring to FIG. 5, in the LCD mirror apparatus according to the exemplary embodiment of the present invention, the LCD mirror driving unit 120 includes a front sensitivity adjusting unit 121, a rear sensitivity adjusting unit 122, and a front / rear sensitivity comparing unit 123. And an AC voltage controller 124.

Since the input DC power source 141 of the LCD mirror apparatus 100 according to the embodiment of the present invention has a low DC voltage of 3 to 24 volts or less, a car battery or a portable battery can be used as a power source. For example, a portable battery may use only a primary battery such as an alkaline battery, a solar cell and a rechargeable secondary battery, or a secondary battery.

The light sensors 111 and 112 are formed of one or more semiconductor light sensors, the front light sensor 111 detects the brightness around the driver including the front of the vehicle, and the rear light sensor 112 is the electronic LCD mirror 130. ) Detects light incident on the LCD mirror 130 from the headlight of the vehicle at the rear of the vehicle. In this case, a silicon photodiode is mainly used as the semiconductor optical sensor. The silicon optical sensor generates a current according to the amount of visible light incident to the incident light. For example, as the amount of incident light increases, the amount of current generated by the optical sensor increases, and the amount of current generated by the semiconductor optical sensor is increased. It can be converted into the amount of light coming from the direction, thereby recognizing the difference in brightness between the front and rear of the vehicle from the difference in the amount of current of each semiconductor light sensor.

The front and rear sensitivity adjusters 121 and 122 select and adjust only the entire amount or a predetermined amount of the current generated by the silicon optical sensors of the optical sensors 111 and 112 to adjust the flow to the front / rear sensitivity comparator 123. At this time, the remaining current that does not flow to the front / rear sensitivity comparison unit 123 among the current generated by the photosensors 111 and 112 is discharged through the resistance. In addition, the sensitivity of each of the photosensors 111 and 112 is different depending on the rate at which the current generated by the photosensors 111 and 112 is discharged. In general, the front optical sensor 111 discharges a larger amount of current than the rear optical sensor 112 so that the rear optical sensor 112 reacts to the change in the amount of light more sensitively than the front optical sensor 111. In addition, an amplifier may be used to further increase the sensitivity of the front or rear optical sensors 111 and 112, and the amplification factor of the amplifier may be changed to vary the sensitivity of each optical sensor 111 or 112. have.

In addition, the malfunction of the LCD mirror 130 is minimized by varying the sensitivity of the optical sensor by varying the amount of discharge current or varying the amplification factor of the amplifier according to the brightness of night and day. For example, when the brightness is greater than a certain level during the day, increasing the sensitivity of the front optical sensor 111 or lowering the sensitivity of the rear optical sensor 112 results in a difference in brightness between the front optical sensor 111 and the rear optical sensor 112. As it is relatively reduced, malfunction can be minimized when passing through a tunnel or through a relatively dark area such as an underground parking lot. Alternatively, when the brightness of the front light sensor 111 is higher than a certain degree, the operation of the LCD mirror 130 is converted to a standby state so that the electronic LCD mirror 130 does not operate during a bright day.

In general, since the silicon optical sensor operates very fast with a response speed of 1 ms or less, when the amount of light incident on the optical sensors 111 and 112 changes, the amount of generated current also changes in a very short time. At this time, since the reaction speed of the general LCD panel is several tens of ms or less, the quick reaction of the LCD mirror 130 by the reaction of the optical sensors 111 and 112 may make the driver's eyes tired.

Therefore, by applying an RC circuit having a time constant of about 0.1 to 30 seconds, the current generated by the optical sensors 111 and 112 is controlled to reduce the response speed of the LCD mirror 130 by controlling the change in current. give. The time constant of the front light sensor 111 minimizes the malfunction of the LCD mirror 130 by delaying the change of the operation standard of the electronic LCD mirror when the environmental change around the driver is suddenly changed. For example, when a relatively strong light is incident on the front optical sensor 111 for a short time, the amount of instantaneous current is increased, and the increased current increases the voltage of the battery and the amount of charge is increased. Therefore, there is a delay of a certain time until the instantaneous increase in current generated by the front light sensor 111 is applied to the operating standard of the LCD mirror 130.

On the contrary, when the amount of light incident on the front optical sensor 111 is momentarily reduced, the amount of generated current is reduced within a short time, the charge accumulated in the battery is discharged, and the voltage of the battery is lowered. There is a time delay before the change is reflected in the operating criteria of the LCD mirror 130. For example, when the street lamps are installed at regular intervals during night driving, when the headlamp light of the vehicle facing the front is incident on the front light sensor 111, the roadside lights or enter the tunnel during the daytime driving. It is possible to prevent the instantaneous operation of the mirror by the instantaneous current change of the optical sensor when or when exiting. In addition, the time constants of the front optical sensor 111 and the rear optical sensor 112 may be slightly different from each other. For example, the time constant of the front optical sensor 111 may be about 3 to 50 seconds, and The time constant of the optical sensor 122 is appropriately about 0.3 to 5 seconds.

The front / rear sensitivity comparing unit 123 converts the currents flowing from the front sensitivity adjusting unit 121 and the rear sensitivity adjusting unit 122 into respective voltages while passing through the resistances. The voltages converted as described above are changed according to the amount of light incident on the light sensor from the light sensors 111 and 112, respectively, and the voltage difference generated between the sensitivity controllers 121 and 122 corresponds to the corresponding light sensor 111. , 112 is related to the relative difference in brightness detected. The relative voltage difference is recognized when the current or voltage of the front sensitivity control unit 121 has a value greater than the current or voltage of the rear sensitivity control unit 122, and the difference value is recognized as zero (0), The value is generally about 5 volts depending on the characteristics of the semiconductor chip used.

The AC voltage controller 124 converts the relative voltage difference generated by the front / rear sensitivity comparator 123 into the voltage level of the AC power supplied from the AC power supply 142 and then supplies it to the LCD mirror 130. At this time, the frequency of the AC voltage is suitable 30 ~ 150Hz, if the frequency is too high, the power consumption increases, the driving voltage of the LCD panel is increased, if the frequency is too low, the brightness of the LCD mirror 130 flickers or The driving voltage characteristics of the LCD panel may change. Here, the waveform of the AC voltage may be a triangular waveform or a sinusoidal waveform, but a square wave is best to prevent the flicker of the LCD mirror 130 if possible.

The LCD mirror 130 is stacked with the LCD panel and the reflection mirror, and the light reflectance is changed according to the voltage applied to the LCD panel. In this case, the LCD panel to be used may be formed in a twisted nematic (TN) mode, an electrically controllable birefringence (ECB) mode, or a vertically aligned (VA) mode. If the voltage applied to the LCD panel is lower than or equal to a certain value or the power is cut off to the LCD mirror 130, the state of brightness is maintained, and if a predetermined voltage or more is applied, the light transmittance of the LCD panel is lowered, so that the reflectance of the LCD mirror 130 is low. You lose.

6 is a diagram illustrating a change in current generation amount (mA) of the silicon optical sensor according to the amount of incident light lux according to an embodiment of the present invention. The degree of change is shown.

FIG. 6 shows a change in current generated according to the amount of light incident by the light sensors of the front and rear light sensors 111 and 112. The amount of current generated according to the intensity of the incident light shows a very good proportional relationship in logarithmic coordinates. That is, as the intensity of light incident on the optical sensor increases, the amount of generated current also increases in proportion. The brightness range of the light sensor on which the LCD mirror 130 operates is approximately 10 to 400 Lux. When the intensity of the light incident on the front optical sensor 111 is 400Lux or more, it is recognized as a day, and the voltage applied to the LCD panel of the LCD mirror 130 becomes below a threshold voltage, and the LCD mirror 130 is in a bright state. The voltage applied to the LCD panel of the LCD mirror 130 is also below the threshold voltage and the LCD mirror 130 remains bright even when the intensity of the light incident on the rear light sensor 112 is 10Lux or less. do.

FIG. 7 is a graph showing light reflectance variation of an LCD mirror according to an applied voltage according to an embodiment of the present invention, and showing a change in reflectance of an LCD mirror by applying an electric field to a liquid crystal layer of the LCD panel.

As shown in FIG. 7, when the AC voltage of 60 Hz is gradually applied to the LCD panel of the LCD mirror 130 from 0 volts to 3 volts, a graph showing a change in reflectance with time of the LCD mirror 130 is shown. As a result, similar results can be obtained when the applied voltage is gradually decreased from 3 volts to 0 volts. The typical twisted nematic (TN) LCD operating time for these LCD panels is several tens of ms. At zero volts in the initial state, the reflectance is about 41%, the reflectance at V1, the voltage between 0 volts and 3 volts, is 30%, the reflectance at V2 is 10%, and the reflectance at 3 volts is 4%. That is, if the voltage applied to the LCD panel of the LCD mirror 130 is arbitrarily selected between 0 and 3 volts, the reflectance of the LCD mirror 130 can be obtained.

In addition, when the voltage applied to the LCD panel of the LCD mirror 130 is changed from the initial voltage to the final voltage, the reflectance of the LCD mirror 130 changes within the reaction rate of the liquid crystal. That is, when the voltage applied to the LCD panel of the LCD mirror 130 is less than the threshold voltage, the LCD mirror 130 maintains a bright state, and when the voltage gradually increases and becomes higher than the threshold voltage, the reflectance of the LCD mirror becomes Gradually decreasing, when the saturation voltage is higher than the reflectivity of the LCD mirror reaches a minimum.

The brightness of the rear incident light and the ambient incident light detected by the front and rear light sensors 111 and 112 are respectively adjusted by the light sensitivity adjusting units 121 and 122, and then, by the front / rear sensitivity comparing unit 123. According to the difference in brightness that the light of the rear incident light gives a glare to the driver, an appropriate voltage is applied to the LCD panel of the LCD mirror 130. That is, when the brightness of the rear incident light of the rear vehicle headlights is strong enough to give a glare to the driver during night driving, a sufficient driving voltage is applied to the LCD panel to reduce the light reflectance of the LCD mirror 130.

For example, if the light from the rear of the vehicle is strong enough to give a glare to the driver, sufficient voltage is applied to the LCD panel to reduce the light reflectance of the LCD mirror 130. On the other hand, when the light around the vehicle is brighter than the light from the rear, since the light reflection of the LCD mirror 130 does not give the driver a glare, a voltage below the threshold voltage is applied to the LCD panel of the LCD mirror 130. . That is, during a bright day, even if the rear vehicle turns on the upper headlight and approaches the vehicle, it is determined that the driver does not cause glare to maintain the high reflectance of the LCD mirror 130.

As shown in FIG. 7, the light reflectance of the LCD mirror 130 may have an intermediate gray scale depending on a voltage applied thereto, and according to the degree and speed of change of the brightness of the surroundings or the brightness of the rear recognized by the plurality of light sensors Within a short time of less than 0.1 second, the LCD mirror 130 may correspond to have an appropriate light transmittance. When the headlights are suddenly turned on at night at the rear of the vehicle to give a severe glare to the driver, the light reflectance of the LCD mirror 130 is rapidly lowered, and when the vehicle at the rear slowly approaches, the LCD mirror (depending on the degree of glare of the driver) The light reflectance of 130 is gradually lowered to several levels of halftone.

In addition, when the vehicle behind the car turns on and off suddenly, or the road surface is not good, the vehicle shakes up and down with the headlights turned on, or suddenly disappears from view, the LCD mirror 130 due to the fast response speed of the LCD mirror 130 The light reflectivity of the) is suddenly changed from a low state to a high state, rather it may cause glare to the driver, so that the LCD mirror 130 gradually brightens over 0.3 seconds to several seconds.

As a result, the LCD mirror device according to the embodiment of the present invention can reduce the glare of the vehicle driver by automatically adjusting the reflectance using an LCD panel having a fast response speed and easy display of halftones, The brightness difference recognized by the rear Si photodiode can be reflected on the LCD panel and driven in a continuous gray scale. In addition, it is possible to easily distinguish between day and night sensitivity by varying the sensitivity of the front optical sensor using a switching element on the basis of a constant brightness. In addition, according to the present invention, by changing the rate of change of the current generated by the front and rear light sensors different from each other it can be optimized to adapt to environmental changes.

The description of the present invention is for the purpose of illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

1 is a perspective view showing the appearance of a general vehicle.

2 is a configuration diagram for explaining a method for adjusting the amount of reflected light using the LCD according to the related art.

3 is a block diagram of the LCD mirror fine-tuning device according to the prior art.

4 is a block diagram of an LCD mirror device according to an embodiment of the present invention.

5 is a detailed view of the LCD mirror apparatus according to the embodiment of the present invention.

6 is a diagram illustrating a change in current generation amount (mA) of a silicon optical sensor according to an incident light amount lux according to an exemplary embodiment of the present invention.

7 is a view illustrating a change in light reflectance of an LCD mirror according to an applied voltage according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

100: LCD mirror device 110: Light sensor

120: LCD mirror drive unit 130: LCD mirror

140: power supply 111: front light sensor

112: rear light sensor 121: front sensitivity control unit

122: rear sensitivity adjustment unit 123: front / rear sensitivity comparison unit

124: AC voltage control unit 141: DC power

142: AC power

Claims (15)

In the LCD (Liquid Crystal Display) mirror device for preventing the glare of the vehicle driver by the light incident from the rear, An LCD mirror installed in the vehicle and configured to adjust the amount of light that is transmitted from the reflective mirror to the driver by varying light transmittance according to an applied LCD driving voltage; An optical sensor including a rear optical sensor that detects light incident on the LCD mirror from the rear of the vehicle and outputs an analog signal, and a front optical sensor which detects light incident from the driver's vicinity and outputs an analog signal; Receives an analog signal output from the front optical sensor and the rear optical sensor, and varies the sensitivity of the light amount respectively detected by the front and rear light sensor, and compares the sensitivity of the variable light amount and the front light sensor An LCD mirror driver configured to determine an LCD driving voltage corresponding to a brightness difference value between the rear incident light and the ambient incident light detected by the rear light sensor, and apply the determined LCD driving voltage to the LCD panel of the LCD mirror; And A power supply unit for applying direct current and alternating current power to the LCD mirror, the optical sensor, and the LCD mirror driving unit, respectively; The LCD mirror driving unit, A front sensitivity control unit for adjusting the sensitivity of the front optical sensor in response to an analog signal output from the front optical sensor; A rear sensitivity control unit for adjusting the sensitivity of the rear optical sensor in response to an analog signal output from the rear optical sensor; A front / rear sensitivity comparison unit configured to determine a predetermined LCD driving voltage by comparing the front sensitivity and the rear sensitivity of each of which the sensitivity is adjusted; And AC voltage adjusting unit for applying the LCD driving voltage determined by the front / rear sensitivity comparison unit to the LCD panel of the LCD mirror LCD mirror device comprising a. The method of claim 1, The optical sensor includes a front optical sensor for recognizing the brightness of the front or surroundings of the vehicle driver and at least one rear optical sensor for recognizing the brightness incident on the LCD mirror from the headlight of the rear vehicle. The method of claim 1, And said optical sensor is a silicon semiconductor diode. delete The method of claim 1, The front sensitivity control unit and the rear sensitivity control unit LCD mirror device, characterized in that for controlling the flow of current generated by the front and rear light sensor, respectively. The method of claim 5, And the front sensitivity adjuster and the rear sensitivity adjuster respectively adjust the amount of use and discharge amount of the current to adjust the flow of the generated current. The method of claim 6, The discharge amount of the LCD mirror, characterized in that for adjusting the amount of resistance connected to the ground. The method of claim 5, And the front sensitivity adjuster and the rear sensitivity adjuster respectively adjust the rate of change of the current flow to adjust the flow of the generated current. 9. The method of claim 8, And the front sensitivity adjuster and the rear sensitivity adjuster adjust a time constant of an RC circuit composed of a resistor and a storage battery to adjust a rate of change of the current flow. The method of claim 1, The front / rear sensitivity comparison unit may set the voltage difference to less than or equal to the threshold voltage of the LCD panel when the intensity of the light incident on the front optical sensor is large enough to recognize it as low. The method of claim 1, And the front / rear sensitivity comparing unit recognizes a difference between a current and a voltage generated from the front sensitivity adjusting unit and the rear sensitivity adjusting unit. 12. The method of claim 11, And the front / rear sensitivity comparator sets the difference value to zero when the current or voltage of the front sensitivity adjuster is greater than the current or voltage of the rear sensitivity adjuster. The method of claim 1, And the AC voltage adjusting unit converts the current or DC voltage difference determined by the front / rear sensitivity comparing unit into an AC voltage level and supplies the AC voltage to the LCD panel of the LCD mirror. The method of claim 1, LCD panel of the LCD mirror, characterized in that consisting of the LCD of the TN mode, ECB mode, or VA mode. The method of claim 1, The power supply unit includes a direct current power source and an alternating current power source, wherein the direct current power source is an automotive mirror, a primary battery, a secondary battery, or a solar cell LCD mirror.

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