Half mirror reflector having LED road sign

Disclosed is a half mirror reflector having an LED road sign, which can be used as a reflector in the daytime and as both a reflector and a road sign in the nighttime. The half mirror reflector comprises: a support plate attached to a support rod; a half mirror fixed to the support plate; an LED road sign mounted on the support plate under the half mirror and having a plurality of LEDs; a PCB substrate mounted on the support plate under the half mirror to control the operation of the LED road sign; and a solar battery module provided at the upper part of the support rod to generate a voltage for operating the LED road sign and supply the voltage to the PCB substrate.

RELATED APPLICATION

This application is related to and claims the benefit of priority to Korean Patent Application No. 2003-0029444, filed May 9, 2003, the entirety of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a half mirror reflector having an LED road sign, and more particularly to a half mirror reflector having an LED road sign, which can be used as a reflector in the daytime and as both a reflector and a road sign in the nighttime.

2. Description of the Prior Art

Cars have become a complex necessity of modern life. As the number of cars on the roads is rapidly increasing, most countries try to expand infrastructures and build more roads to solve road traffic problems. However, countries having small land areas and relatively high population densities, such as Korea, have poor road conditions compared to the growing number of cars. Such countries have difficulties in securing enough money and available land area to build more roads, including highways, to keep up with the growing number of cars.

The increase in cars causes problems on roads and causes traffic accidents. In poor road conditions and particularly on winding or curved roads, it is critical for drivers to rapidly perceive the condition of the road invisible beyond sharp curves.

Therefore, circular half mirror reflectors are generally installed at the corners of curved roads to enable drivers to see the condition of forthcoming road beforehand. The circular half mirror reflectors help drivers not only to check ahead the road condition of the direction to which they will turn, but also to show their presence to the vehicles approaching in the opposite direction, thereby preventing possible traffic accidents.

FIG. 1is a perspective view of a conventional stainless road reflector.

Referring toFIG. 1, a conventional stainless road reflector comprises a convex mirror3fixed to a support plate2, a hood4attached to the upper part of the support plate2, a fixing bracket5for fixing the support plate2to a support rod1by a bolt/nut assembly6, and a cap7for covering the top of the support rod1.

The mirror3is formed from a metal having high reflectivity (for example, stainless steel). The mirror3is machined precisely to have a convex surface that bulges outward at the center thereof.

Since the mirror3is made of stainless steel, the conventional stainless road reflector is very weak against stones or other external shocks. Also, the stainless mirror3is easily scratched or discolored due to its inferior durability and therefore has a short life.

The conventional stainless road reflector may fail to perform its required function because it is easily crushed or scratched by external shocks and gets discolored with time.

In addition, the conventional stainless road reflector cannot ensure sufficient reflection of an object to enable drivers to check the condition of road ahead in the dark or at night.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and one object of the present invention is to provide a half mirror reflector having an LED road sign, which can be used as a reflector in the daytime and as both a reflector and a road sign in the nighttime.

Another object of the present invention is to provide a half mirror reflector having an LED road sign, which can be used as both a reflector and a road sign in a place which is dark even during daytime (for example, in an underground parking lot) by turning on a switch provided on the reflector to supply a DC power to the LED road sign.

Still another object of the present invention is to provide a half mirror reflector having an LED road sign, which is made of polycarbonate (PC) or acryl to improve object reflectivity and endurance to withstand external shocks and to prevent its surface from easily being discolored.

Still another object of the present invention is to provide a half mirror reflector having an LED road sign and operating by means of a solar battery.

Still another object of the present invention is to provide a half mirror reflector having an LED road sign, which converts a current generated by a solar battery to a constant current using a current transformer and supplies the constant current to the LEDs in the LED road sign, thereby ensuring semipermanent use of the LEDs.

In order to accomplish the above objects, there is provided a half mirror reflector comprising: a support plate attached to a support rod; a half mirror fixed to the support plate; an LED road sign mounted on the support plate under the half mirror and having a plurality of LEDS; a PCB substrate mounted on the support plate under the half mirror to control the operation of the LED road sign; and a solar battery module provided at the upper part of the support rod to generate a voltage for operating the LED road sign and supply the voltage to the PCB substrate.

The half mirror reflector further comprises a storage battery mounted on the support plate under the half mirror to store a voltage supplied from the solar battery module and transfer the stored voltage to the PCB substrate.

The half mirror has a convex circular or quadrangular shape.

After forming an aluminum thin film on one side of the half mirror, a transparent coating is applied on both sides of the half mirror.

The half mirror contains a UV protector.

The half mirror is formed from polycarbonate (PC) or acryl.

The half mirror reflector having an LED road sign further comprises: a support bracket fixed to the rear of the support plate; a first bracket fixed to the support bracket; and a second bracket having one end fixed to the first bracket and the other end fixed to the support rod.

The half mirror reflector having an LED road sign further comprises a third bracket for fixing the solar battery module to the upper part of the support rod.

The PCB substrate includes: a first diode for rectifying a direct current generated from the solar battery module and outputting the rectified direct current to a first node; a storage battery for storing a voltage of the first node; a photosensor coupled between the first node and a ground voltage to sense ambient light; a switch box for receiving power from the first node, generating a control signal for operating LEDs in the LED road sign using the photosensor or a switch and outputting the control signal to a third node; a first transistor for switching the voltage of the first node by a voltage of the third node; a current transformer for converting a first current supplied from the first node through first and second inductors by the switched voltage from the first transistor and generating a second current to be outputted to a third inductor; a second transistor for switching a current to flow through the first and second inductors by the switched voltage from the first transistor; and a second diode for rectifying a current outputted from the current transformer and supplying the rectified current to a plurality of LEDs in the LED road sign.

The PCB substrate further includes: a first resistor coupled between the photosensor and a ground voltage; a second resistor coupled between an output terminal of the switch box and the third node; a third resistor coupled between the third node and a ground voltage; a fourth resistor coupled between one end terminal of the first transistor and a ground voltage; and a fifth resistor coupled between one end terminal of the first transistor and one end terminal of the second inductor.

The first transistor is a PNP bipolar transistor, while the second transistor is an NPN bipolar transistor.

The PCB substrate includes: a bridge diode for converting an AC power into a DC power and outputting the DC power; a plurality of LEDs and a FET switching element connected in series between an output terminal of the bridge diode and a ground voltage; a switching pulse generating IC for receiving the DC power outputted from the bridge diode and generating a switching pulse signal; and an eleventh transistor for driving the FET switching element according to the switching pulse signal.

The PCB substrate further includes: a protective resistor coupled between an output terminal of the bridge diode and an input terminal of the switching pulse generating IC; and a zener diode for maintaining a constant DC voltage to be inputted to the switching pulse generating IC.

The switching pulse generating IC includes a frequency generator for generating a frequency according to an RC time constant and a pulse width controller for controlling a pulse width of a switching pulse.

The eleventh transistor is an NPN bipolar transistor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2is a perspective view of a half mirror reflector having an LED road sign according to the present invention.FIG. 3is a rear perspective view of the half mirror reflector ofFIG. 2.

Referring toFIGS. 2 and 3, the half mirror reflector100comprises: a convex half mirror23fixed to a support plate22and made of polycarbonate (PC); a hood24attached to the upper part of the support plate22; first and second brackets43and44for fixing the support plate22to a support rod21by bolt/nut assemblies45and46; a cap27for covering the top of the support rod21; and a solar heat solite (hereinafter referred to as “solar battery module”) fixed to the upper part of the support rod21by a third bracket28.

As shown inFIG. 3, the half mirror reflector100provides a support bracket41at the rear of the support plate22onto which the half mirror23is fixed. The first bracket43is fixed to the support bracket41. Also, one end of the second bracket44is fixed to the first bracket43, while the other end is fixed to the support rod21, thereby connecting the support plate22to the support rod21. The second bracket44has a circular fixing tube44afor embracing and fixing the support rod21. The second bracket44is fixed to the first bracket43by the bolt/nut assembly45through a first assembling hole (not shown) formed at one side of the circular fixing tube44a. Also, the second bracket44is fixed to the support rod21by the bolt/nut assembly46through a second assembling hole (not shown) formed at the other side of the circular fixing tube44a.

The solar battery module30has a photosensor (not shown) which converts light energy into electric energy.

Also, another photosensor PS and a switch SW are provided at the rear of the support plate22. The photosensor PS senses ambient light and turns on LEDs51in the LED road sign50(FIG. 4) at night. If the half mirror reflector100is installed in a place which is dark even during daytime (for example, in an underground parking lot), the switch SW can control the half mirror reflector100to input a DC power to the LEDs51in the LED road sign50(FIG. 4) for DC operation.

More specifically, when the switch SW is on, the half mirror reflector100supplies an AC power (220V) to the LEDs51in the LED road sign50. When the switch SW is off, the half mirror reflector100supplies a DC power generated from the solar battery module30to the LEDs51in the LED road sign50.

The half mirror23is made of transparent polycarbonate (PC) or acryl. The half mirror23is about 250 times stronger than general window glass and about 50 times stronger than acryl. Since the half mirror23contains a UV protector, it has excellent durability and endurance to withstand external shocks. Also, the half mirror23is as light as half of a conventional stainless reflector mirror. The half mirror23can be semipermanently used because its surface does not become discolored with time.

Hereinafter, a method for manufacturing the half mirror reflector according to the present invention will be briefly explained.

A half mirror23is formed by cutting a polycarbonate plate in predetermined shape (circular or quadrangular) and size and machining the cut plate to have a convex surface that bulges outward at the center thereof. After forming an aluminum thin film on one side of the half mirror23, a transparent coating is applied on both sides of the half mirror23.

Accordingly, the half mirror23has improved object reflectivity and can prevent any distortion or scratch marks caused by external shocks. Also, the half mirror23can have a longer life.

FIG. 4is an exploded perspective view of the half mirror reflector100ofFIG. 2.

As shown inFIG. 4, the half mirror reflector100includes: a support plate22having a hood24formed at the upper part thereof; an LED road sign50mounted on the support plate22and having a plurality of LEDs51to indicate a road condition; a PCB substrate53mounted on the support plate22to operate the LED road sign50; and a storage battery54mounted on the support plate22to store electric energy supplied from the solar battery module30and supply power to the LED road sign50through the PCB substrate53. A half mirror23is tightly fixed to the support plate22on which the LED road sign50, PCB substrate53and storage battery54are mounted, using a half mirror assembly band55.

The LED road sign50is fastened to the center of the support plate22by means of a rivet52. The hood24provided at the upper part of the support plate22serves as a rain-screen when it rains.

InFIG. 4, the PCB substrate53and the storage battery54are illustrated as being positioned respectively at the lower and upper parts of the LED road sign50for explanatory convenience. Actually, however, the PCB substrate53and the storage battery54are placed and sealed at the rear of the LED road sign50so that they can be protected from moisture, rainwater or other contaminants.

The solar battery module30is a device that converts light energy into electric energy. The energy conversion efficiency of the solar battery module30is above 18% for a Si semiconductor and over 28% for a GaAs semiconductor according to the concentration rate (solar collector aperture area/light harvesting surface area). The storage battery54supplies constant voltage and current to the LED road sign50on cloudy days (days having less amount of light) or at night. The storage battery54can be used at a high temperature (for example, 70° C.) or at a low temperature (for example, −40° C.). The storage battery54has a sufficiently large capacity (for example, 2,800 mah) to operate the LED road sign50for a predetermined period of time (for example, 15 days to 30 days), even without being supplied with power from the solar battery module30.

FIG. 5shows examples of the LED road sign50according to the present invention.

The LED road sign50indicates a roadway condition as illustrated inFIG. 5(a)–(e), using a plurality of LEDs51. Sign (a) warns drivers of a sharp curve at the right side. Sign (b) warns drivers of a sharp curve at the left side. Sign (c) alerts drivers to move/merge left (a1) or right (b1). Sign (d) warns drivers of a left sharp curve (a1, a2) or a right sharp curve (b1, b2). Sign (e) alerts drivers to move/merge left (a1) or right (b1).

The half mirror reflector100having the LED road sign50enables drivers to see vehicles approaching in the opposite direction through the half mirror23in a curved road. Also, the half mirror reflector100turns on the LED road sign50placed under the half mirror23at night so that drivers can see the LED road sign50from a distance and check any curve ahead for safe driving.

FIG. 6is a circuit diagram showing a DC voltage related circuit of the LED road sign50according to the present invention.

Referring toFIG. 6, the DC voltage circuit of the LED road sign50includes: a solar battery module30for converting light energy into electric energy (DC voltage); a first diode D1for rectifying the DC voltage outputted from the solar battery module30and outputting the rectified DC voltage to a first node Nd1; a storage battery54for storing a current transferred to the first node Nd1; a capacitor C coupled between the first node Nd1and a ground voltage Vss; a photosensor PS and a first resistor R1connected in series between the first node Nd1and a ground voltage Vss; a switch box101for receiving power from the first node Nd1, generating a control signal for operating LEDs in the LED road sign50using the photosensor or a switch and outputting the control signal to a third node Nd3; a second resistor R2coupled between an output terminal of the switch box101and the third node Nd3; a third resistor R3coupled between the third node Nd3and a ground voltage; a PNP bipolar transistor TR1for switching a voltage of the first node Nd1to a fourth node Nd4by a voltage of the third node Nd3; a fourth resistor R4coupled between the fourth node Nd4and a ground voltage Vss; a fifth resistor R5coupled between the fourth node Nd4and a fifth node Nd5; a first inductor L1coupled between the first node Nd1and a sixth node Nd6; a second inductor L2coupled between the fifth node Nd5and a seventh node Nd7; an NPN bipolar transistor TR2for flowing a voltage of the sixth node Nd6to a ground voltage Vss by a voltage of the seventh node Nd7; a current transformer CT coupled between the fifth node Nd5and an eighth node Nd8to convert a first current induced to the first and second inductors L1and L2by the NPN bipolar transistor TR2and generating a second current to be outputted to the eighth node Nd8; a second diode D2for rectifying the current of the eighth node Nd8and transferring the rectified current to a ninth node Nd9; and a plurality of LEDs LED1to LEDn connected in series between the ninth node Nd9and a ground voltage Vss.

In the DC voltage related circuit of the LED road sign50, the switch box101is operated by the switch SW or the photosensor PS. The switch box101applies a voltage to the third node Nd3, whereby the PNP bipolar transistor TR1operates to apply the voltage of the first node Nd1to the seventh node Nd7through the fifth resistor R5, fifth node Nd5and second inductor L2. Accordingly, the NPN bipolar transistor TR2operates to flow a current through the first inductor L1. The current transformer CT consisting of the first to third inductors L1to L3generates the second current according to the first current induced to the first and second inductors L1and L2. The second current generated from the current transformer has a constant current and voltage, and is supplied to the plurality of LEDs LED1to LEDn in the LED road sign50through the second diode D2. If at least one of the LEDs LED1to LEDn does not properly operate, the problematic LED will be shorted and the other LEDs will normally operate.

FIG. 7is a circuit diagram showing an AC voltage related circuit of the LED road sign according to the present invention.

Referring toFIG. 7, the AC voltage related circuit of the LED road sign includes: an eleventh capacitor C11for limiting the current of a first AC power AC1and transferring the limited current to an eleventh node Nd11; bridge diodes D11to D14for receiving the first AC power AC1and a second AC power AC2, converting a DC power and outputting the converted DC power to a thirteenth node Nd13; a plurality of LEDs LED1to LEDn connected in series between the thirteenth node Nd13and a twentieth node Nd20; an eleventh resistor R11coupled between the thirteenth node Nd13and a fourteenth node Nd14; a twelfth capacitor C12coupled between the thirteenth node Nd13and a ground voltage Vss; a zener diode D15coupled between the ground voltage Vss and the fourteenth node Nd14; a thirteenth capacitor C13coupled between the ground voltage Vss and the fourteenth node Nd14; a switching pulse generating IC110for inputting a DC power transferred to the fourteenth node Nd14; a twelfth resistor R12and a fourteenth capacitor C14coupled between an input terminal of the switching pulse generating IC110and a ground voltage Vss to generate a frequency according to an RC time constant; a thirteenth resistor R13, a sixteenth diode D16and a fifteenth capacitor C15coupled between the input terminal of the switching pulse generating IC110and a ground voltage Vss to regulate the switching pulse width; a fifteenth resistor R15coupled between a switching pulse output terminal of the switching pulse generating IC110and a nineteenth node Nd19; a fourteenth resistor R14coupled between the output terminal of the switching pulse generating IC110and an eighteenth node Nd18; an NPN bipolar transistor TR11for switching a voltage of the eighteenth node Nd18to a ground voltage Vss by the voltage of the nineteenth node Nd19; and an FET switching element for switching a voltage of a twentieth node Nd20to a ground voltage Vss by the voltage of the eighteenth node Nd18.

In the AC voltage related circuit of the LED road sign50, when an AC power is applied by the switch SW, the switching pulse generating IC110generates a switching pulse signal and outputs the signal to the nineteenth node Nd19and thereby turns on the NPN bipolar transistor TR11. Accordingly, the FET switching element is turned on to operate the plurality of LEDs LED1to LEDn.

The half mirror reflector100having the LED road sign50can be installed in a place which is dark even during daytime (for example, in an underground parking lot). If the switch SW provided at the rear of the support plate22is turned on, a DC power will be inputted to operate the LEDs51in the LED road sign50(FIG. 4). In other words, if the half mirror reflector100having the LED road sign50is installed in a place where the photosensor PS does not operate, it is possible to operate the LED road sign50all day long by turning on the switch SW. The half mirror reflector100will then serve as both a road reflector and a LED road sign.

If the half mirror reflector100having the LED road sign50is installed in a place which is bright during daytime (for example, on a road), the switch SW should be turned off. When it gets dark (on a cloudy day or at night), the half mirror reflector110supplies the DC power stored in the storage battery54to the LEDs in the LED road sign50to turn on and operate the LEDs. The LEDs in the LED road sign50are turned off during daytime. The half mirror reflector100is used as both a reflector and an LED road sign at night or in the dark, while it is used solely as a reflector in the daytime.

As described above, the half mirror reflector having an LED road sign according to the present invention can be used as a reflector in the daytime and as both a reflector and a road sign in the nighttime. If the half mirror reflector is installed in a place which is dark even during daytime (for example, in an underground parking lot), it can input a DC power by turning on a switch SW and operate the LED road sign for 24 hours a day.

The half mirror reflector is made of polycarbonate to improve object reflectivity and endurance against external shocks and prevent its surface from easily being discolored.

The LED road sign provided within the half mirror reflector is driven by a solar battery. Also, the half mirror reflector having the LED road sign converts a current generated by a solar battery to a constant current using a current transformer and supplies the constant current to the LEDs in the LED road sign, thereby ensuring semipermanent use of the LEDs.