JPH07218238A - Knob operating amount detector of dimmer for vehicle and dimming circuit thereof - Google Patents

Abstract

PURPOSE:To easily alter dimming characteristics, to prevent flicker of illumination and to improve durability. CONSTITUTION:A knob 4 is rotatably and operably supported to a rheostat 1. A disk 7 formed with a slit altered in width along its circumferential direction is rotatably supported to the rheostat 1, and rotated by the knob 4. A photointerrupter 15 is mounted on a printed board 13 of the rheostat 1. The photointerrupter 15 has a light emitting diode 15a and a photoreceiver 15b and is so formed that the diode 15a is opposed to the photoreceiver 15b via the slit of the disk 7. When the disk 7 is rotated by the knob 4, a light irradiated from the diode 15a is received by the photoreceiver 15b in quantity responsive to the width of the slit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knob operation amount detector and a dimming circuit of a vehicle light control device, and more specifically, to a dimmer for adjusting the brightness of an illumination provided in an instrument such as an automobile speedometer. It relates to an optical device (rheostat).

[0002]

2. Description of the Related Art Generally, an instrument such as a speedometer of an automobile is provided with a lighting so that the instrument can be easily seen at night. However, since the illumination is too bright depending on the brightness of the outside of the automobile, a vehicle light control device (rheostat) for adjusting the brightness of the illumination is provided.

As shown in FIG. 7, the rheostat 50 is provided with a knob 51 for adjusting the brightness of illumination. A volume 52 is attached to the knob 51, and the volume 52 is mounted on a printed circuit board 53. The volume 52 is set such that its resistance value is based on the operation amount of the knob 51, as shown in FIG. 8, for example. Further, the rheostat 50 has an output connector 54.
Although not shown, a printed circuit board 55 on which elements forming an oscillation circuit and an amplification circuit are mounted is provided, and is connected to the printed circuit board 53 by a jumper wire 56. Driving power is supplied to the output connector 54 from a battery (not shown). An illumination lamp (not shown) is connected to the output connector 54. The oscillator circuit oscillates a rectangular wave having a preset frequency. Then, the knob 51 is operated to change the resistance value of the volume 52, and the ratio (duty) of the time when the oscillation circuit is turned on and off is changed, thereby changing the amount of current flowing through the lamp of the illumination and adjusting the brightness. It is supposed to do.

[0004]

By the way, as shown in FIG. 8, the resistance of the potentiometer 52 is set to the operating range 5 of the knob 51.
The resistance value does not change at 7, 59 and the operating range 58
Is set to change linearly. This change in resistance value is set by connecting a conductor whose resistance value does not change and a printing resistor having a predetermined resistance value. for that reason,
In order to change the dimming characteristic of the lamp, the resistance value needs to be replaced with the volume 52 that matches the dimming characteristic, and there is a problem that the dimming characteristic cannot be easily changed. Further, since noise may occur at the connection point between the conductor and the printing resistor, the noise causes the illumination of the instruments to flicker, making it difficult to see.

Further, a brush made of copper or the like is brought into contact with the conductor and the printing resistor to obtain a resistance value according to the operation amount of the knob 51. Therefore, the durability of the volume 52 is influenced by the durability of the conductor and the printing resistor, and the durability of the rheostat 50 is determined. Therefore, there is a problem that the durability of the volume 52 must be taken into consideration when designing the rheostat 50.

Further, in order to prevent the terminal portion 52a of the volume 52 from being stressed by the eccentricity of the knob 51 and the volume 52, it is composed of two printed circuit boards 53 and 55, and the printed circuit board 53 can move by an amount corresponding to the eccentricity. I am trying. In addition, the printed circuit boards 53 and 55 are jumper wires 59.
The signal lines are connected to each other by. Therefore, there is a problem that the assembly is time-consuming and the manufacturing cost is high.

The present invention has been made to solve the above-mentioned problems, and its purpose is to easily change the dimming characteristics, to prevent flicker of illumination, and to improve durability. It is an object of the present invention to provide a knob operation amount detector of a vehicle light control device and a light control circuit.

[0008]

In order to solve the above problems, the invention according to claim 1 adjusts the current flowing through the lamp based on the operation amount of a knob rotatably supported by the case. A knob operation amount detector of a vehicle light control device adapted to adjust the brightness of the lamp, wherein the case supports a disk in which the amount of light transmitted or reflected by the rotation changes, and the disk is mounted on the case. The gist of the present invention is that it can be rotated by operating the knob, and that a photo interrupter composed of a pair of a light emitting diode and a light receiving element is arranged on the peripheral portion of the disk.

According to a second aspect of the present invention, a disc is formed with slits having different widths in the circumferential direction, and a pair of a light emitting diode and a light receiving element which face each other with the slit sandwiched therebetween. The gist of the present invention is to dispose a photointerrupter composed of the above, and to allow the light receiving element to receive a change in the amount of light emitted from the light emitting diode and transmitted through the slit due to the rotation of the disk.

Further, the invention according to claim 3 is the same as claim 2
The triangular wave of a predetermined frequency generated by the oscillation circuit unit based on the voltage corresponding to the light amount detected by the knob operation amount detector of the vehicle light control device described in (3) is shaped into a pulse wave having a duty corresponding to the voltage. And a load drive circuit section for flowing a current according to the pulse wave shaped by the waveform shaping circuit section to the lamp.

[0011]

Therefore, according to the first aspect of the invention, the disk is rotatably supported by the case and is rotated by the operation of the knob.
The rotation changes the amount of light transmitted or reflected. The photo interrupter is composed of a pair of light emitting diode and light receiving element, and is arranged at the peripheral portion of the disc.

According to the second aspect of the present invention, the disk is formed with slits having different widths along the circumferential direction thereof, and a pair of the light emitting diode and the light receiving element facing each other with the slit sandwiched therebetween. A photointerrupter is provided, and a light receiving element receives a change in the amount of light emitted from the light emitting diode and transmitted through the slit due to the rotation of the disc.

According to a third aspect of the present invention, the waveform shaping circuit section oscillates based on the voltage corresponding to the light amount detected by the knob operation amount detector of the vehicle light control device according to the second aspect. The triangular wave having a predetermined frequency generated by the section is shaped into a pulse wave having a duty corresponding to the voltage. Then, the load drive circuit section causes a voltage corresponding to the shaped pulse wave to flow through the lamp.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention will now be described with reference to FIGS.
It will be described with reference to FIG. As shown in FIGS. 1 and 2, the rheostat 1 is provided with a case 2 and a connector portion 3. The case 2 is formed in a substantially rectangular parallelepiped shape, and the connector portion 3 is fitted into one side surface (right side in the drawing) of the case 2. The case 2 is provided with a disc-shaped knob 4. The knob 4 is rotatable integrally with a shaft 5 rotatably supported by the case 2. Further, a part of the knob 4 projects to the other side surface (left side in the drawing) of the case 2 so that the knob 4 can be rotated. A gear 6 is provided on the upper surface 4 a of the knob 4 so as to rotate integrally with the knob 4.

A disk 7 is provided on the case 2. The disk 7 is made of acrylic resin colored black and is designed to rotate integrally with a shaft 8 rotatably supported by the case 2. A gear 9 is formed on the outer peripheral edge of the disk 7 and meshes with the gear 6. Therefore, the disk 7 is rotated by rotating the knob 4.

As shown in FIG. 3A, the disk 7 is formed with a slit 10 corresponding to a preset dimming characteristic. That is, the slit 10 is provided so that light can be transmitted in the vertical direction of the disk 7. The width of the slit 10 is gradually narrowed along the circumferential direction of the disk 7, and the slit 10 is formed so that most light is transmitted at point A and almost no light is transmitted at point B. Also,
At point C of the disk 7, no light is transmitted.

A stopper 11 is formed on the ceiling surface 2a of the case 2 so as to project downward. A locking portion 12 is formed on the shaft 8 so as to project in the vertical direction (lateral direction). The locking portion 12 is formed at a position where it can come into contact with the stopper 11, and limits the rotation of the disk 7 in the abutting state.

A printed circuit board 13 is provided on the case 2. A plurality of circuit elements shown in FIG. 4 are mounted on the printed circuit board 13, and are fixed by the locking portions 14 a and 14 b provided on the bottom surface 2 b of the case 2 and the connector portion 3. A photo interrupter 15 as a detection means is mounted on the upper surface (mounting surface) 13a of the printed board 13.

The photo interrupter 15 is a transmissive type having a U-shape and is a light emitting diode 1 as a light emitting portion.
5a and a light receiving element 15b as a light receiving portion are provided so as to face each other, and a change in the light amount on the light receiving side due to an object between the light emitting diode 15a and the light receiving element 15b is detected in a non-contact manner. In the photo interrupter 15, the light from the light emitting diode 15a passes through the slit 10 and the light receiving element 1
It is provided at a position where light is received by 5b. When the disk 7 is rotated by operating the knob 4, the width of the slit 10 between the light emitting diode 15a and the light receiving element 15b changes, and the amount of light received changes according to the change. Then, the stopper 11 gradually changes the amount of light in the light receiving element 15b, that is, C from the point A to the point B of the disk.
It is formed so as to restrict rotation from the point A to the point C directly.

An output connector 16 is mounted on the printed board 13. As shown in FIG. 2, the output connector 16 is formed with a plurality of terminals (three terminals in this embodiment, terminals T, L, E) projecting into the housing 3 a of the connector portion 3. .

Next, the electrical construction of the rheostat 1 will be described. As shown in FIG. 4, the rheostat 1 is provided with an oscillation circuit unit 21, a duty changing circuit unit 22, a waveform shaping circuit unit 23, and a load drive circuit unit 24. Further, the rheostat 1 is provided with terminals T, L, E of the output connector 16 shown in FIG. A battery (not shown) mounted on the vehicle is connected to the terminal T so that the battery power + B is supplied. A lighting lamp 30 is connected between the terminals T and L, and the terminal E is grounded.

A resistor R15, a capacitor C6 and a Zener diode ZD are connected to the terminal T via a diode D2.
And a smoothing circuit consisting of 1 and a driving power source V0 from the battery power source + B to each circuit section 21 to 24 through the smoothing circuit.
Is being stably supplied.

Explaining each of the circuit parts 21 to 24,
The oscillator circuit unit 21 includes resistors R1 to R5 and capacitors C1 and C1.
It has a C2 and an operational amplifier M1. Operational amplifier M1
The drive power source V0 is supplied to its plus power source terminal, and the minus power source terminal is grounded via the terminal E.
The operational amplifier M1 oscillates with the resistor R5 and the capacitor C2, and outputs a triangular wave Vb from its output terminal. As shown in FIG. 5, the triangular wave Vb has a resistance R5.
And a frequency corresponding to the time constant determined by the capacitor C2 and an amplitude corresponding to the voltage determined by the resistors R1 to R4 and input to the non-inverting input terminal. The triangular wave Vb is output to the waveform shaping circuit unit 23.

The duty change circuit section 22 includes the photo interrupter 15 and the resistors R6 to R10 described above. The light emitting diode 15a of the photo interrupter 15 has its anode supplied with the drive power source V0 and its cathode connected to the terminal E via the resistor R6, that is, grounded, and always emits infrared light. The light receiving element 15b is an NPN type phototransistor, the drive power source is supplied to the collector via the resistor R7, and the emitter is grounded via the resistor R8. The waveform shaping circuit section 23 is connected between the resistor R7 and the light receiving element 15b via the resistor R10.

The light receiving element 15b receives a light amount corresponding to the width of the slit 10 due to the rotation of the disk 7, and has an on-resistance corresponding to the light amount. This on resistance and resistance R7, R
A voltage Vc obtained by dividing the drive power source V0 by 8 is output to the waveform shaping circuit section 23. Therefore, the voltage Vc output from the duty changing circuit unit 22 has a value corresponding to the rotation of the disk 7, that is, the operation amount of the knob 4.

The waveform shaping circuit section 23 includes an operational amplifier M2, resistors R11 to R14, capacitors C3 and C4, a diode D1, and a zener diode ZD2. The operational amplifier M2 inputs into its non-inverting input terminal a voltage Vc generated by the duty changing circuit section 22 in proportion to the operating angle of the knob 4, and inputs into its inverting input terminal the triangular wave Vb generated by the oscillation circuit section 21. . Then, the operational amplifier M2 outputs an L level when the voltage of the triangular wave Vb is higher than the voltage Vc, and conversely H when it is lower than the voltage Vc.
It is designed to output the level. That is, the operational amplifier M2 corresponds to the input triangular wave Vb and the voltage Vc in FIG.
It is converted (shaped) into a pulse wave Vd having a ratio (duty) of the time of ON and the time of OFF shown in FIG. Then, the generated pulse wave Vd is output to the load drive circuit unit 24.

Although not shown in the figure for the operational amplifier M2, the drive power source V0 is supplied to its plus power source terminal,
The negative power supply terminal is grounded via the terminal E. The load drive circuit section 24 includes an output transistor Q1.
And a capacitor C5. Output transistor Q
1 is a power MOS FET (Metal Oxide Semiconducto)
r Field Effect Transistor), and the pulse wave Vd shaped by the waveform shaping circuit unit 23 is input to its gate terminal. The source terminal of the output transistor Q1 is grounded via the terminal E, and the drain terminal is connected to the lamp 30 via the terminal L. The output transistor Q1 is on / off controlled by the pulse wave Vd input to its gate terminal,
When 1 is turned on, a current flows from the battery through the lamp 30 and the output transistor Q1.

Next, the operation of the rheostat of this embodiment constructed as described above will be explained. When the battery voltage + B of the battery is applied to the rheostat 1 via the terminal T, the drive voltage V0 is stably supplied to each of the circuit parts 21 to 24 in accordance with the battery voltage + B. Then, the oscillating circuit section 21 generates a triangular wave Vb having a predetermined frequency and outputs it to the waveform shaping circuit section 23.

The waveform shaping circuit section 23 generates (shapes) a pulse wave Vd having a duty based on the triangular wave Vb input from the oscillation circuit section 21 and the voltage Vc input from the duty changing circuit section 22, and the load drive circuit section 24. Output to. In the load drive circuit section 24, the output transistor Q1 is on / off controlled based on the input pulse wave Vd. As a result, the lamp 30 becomes bright according to the duty of the pulse wave Vd.

When the knob 4 is operated, the disk 7 is rotated by the operation and the amount of light transmitted by the slit 10 is changed. Then, the on-resistance value of the light receiving element 15b of the photo interrupter 15 changes based on the change of the light amount.
Then, the voltage Vc obtained by dividing the drive power source V0 by the ON resistance value and the resistors R7 and R8 is output to the waveform shaping circuit section 23.

The waveform shaping circuit section 23 generates (shapes) a pulse wave Vd whose duty is changed based on the triangular wave Vb input from the oscillation circuit section 21 and the voltage Vc input from the duty changing circuit section 22. The output transistor Q1 is turned on by the pulse wave Vd whose duty is changed.
Since it is turned off, the brightness of the lamp 30 changes.

As described above, according to this embodiment, the disk 7
A slit 10 having a changed width is formed along the circumference thereof, and the disk 7 is rotated by a gear 6 provided on the knob 4. The amount of light received by the light receiving element 15b of the photo interrupter 15 is adjusted by the width of the slit 10 formed in the disk 7. And
The brightness of the lamp 30 is adjusted by changing the duty of the pulse wave Vd for controlling the on / off of the output transistor Q1 according to the amount of the received light. As a result, the dimming characteristic of the lamp 30 can be easily changed only by exchanging the disc 7 with the slit 10 having a different shape. Further, since the disk 7 and the photo interrupter 15 are coupled by light and are not in contact with each other, the conventional volume 5
As in No. 2, noise due to contact is eliminated, and the flicker of the lamp 30 can be eliminated. Further, since the disk 7 rotated by the knob 4 and the photo interrupter 15 are not in contact with each other, no force for operating the knob 4 is applied to the printed board 11. As a result, it is not necessary to use two printed circuit boards 13, the cost can be suppressed, and the assembly process can be reduced.

The present invention may be carried out in the following modes other than the above embodiment. (1) The disk 7 of the above embodiment may be replaced with a disk 31 having a different thickness as shown in FIG.
The thicker the disc 31, the smaller the amount of light that passes through. Therefore, the change in the thickness of the disk 31 becomes the dimming characteristic of the lamp 30.

Further, as shown in FIG. 3C, the disc 3
The ratio of black dots formed by printing or the like on the surface of No. 2 is changed to adjust the amount of transmitted light. That is, the amount of light transmitted at point D is the smallest, the amount of light transmitted increases as the lens rotates to point E, and the amount of light transmitted at point F is the largest. Thereby, the ratio of the current flowing through the phototransistor 15 to the operation amount of the knob 4 can be arbitrarily changed, that is, the change in the brightness of the lamp 30 can be arbitrarily set.

(2) Photointerrupter 1 of the above embodiment
5 is a reflection type photo interrupter 33 as shown in FIG.
To the light emitting diode 3 using the disk 7 as a reflector.
The light emitted from 3a is reflected by the disk 7 and received by the light receiving element 33b. At that time, in the disk 7 of FIG. 3A, a reflecting portion having the same shape is formed instead of the slit 10 so as to reflect light. Also,
In the disk 32 of FIG. 3C, the light amount reflected at the point D is small and the light amount reflected at the point F is large. As a result, the dimming characteristic of the lamp 30 can be easily changed as in the above embodiment. Further, since it is non-contact, it is possible to prevent the generation of noise and improve the durability.

(3) The circuit configuration of the rheostat 1 of the above embodiment is appropriately changed to a configuration using a transistor or the like. (4) Instead of the gears 5 and 9 of the above embodiment, the disk 7 is rotated based on the operation of the knob 4 with the pulley and the belt.

(5) ABS the disk 7 of the above embodiment
Conduct using other materials such as (acrylonitrile, butadiene, styrene) resin. The technical ideas other than the claims that can be understood from the above embodiments will be described below along with their effects.

(1) In the first aspect, the detecting means 15 is a reflection type photo interrupter, and the brightness of the lamp 30 is adjusted based on the amount of light reflected from the disk 7. Thereby, the adjustment characteristic of the lamp 30 can be easily changed.

(2) In the first or second aspect, the disk 7 is formed so that its thickness changes along the circumferential direction, and the amount of transmitted light changes depending on the thickness. The dimming characteristic of the lamp 30 can be easily changed by arbitrarily changing the thickness.

[0040]

As described above in detail, according to the present invention, it is possible to easily change the dimming characteristic, prevent flicker of illumination, and improve durability. .

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a vehicle light control device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the vehicle light control device of the embodiment.

FIG. 3A is a plan view of a disc according to an embodiment,
(B) is sectional drawing of the disc of another example, (c) is a top view of the disc of another example.

FIG. 4 is a circuit diagram of a light control circuit of a vehicle light control device according to an embodiment.

FIG. 5 is a waveform diagram showing the voltage at each point of the vehicle light control device.

FIG. 6 is a vertical cross-sectional view showing another vehicle light control device.

FIG. 7 is a vertical cross-sectional view showing a conventional vehicle light control device.

FIG. 8 is a resistance change characteristic diagram of a volume used in a conventional vehicle light control device.

[Explanation of Codes] 4 ... Knob, 7 ... Disc, 15 ... Photointerrupter,
15a ... Light emitting diode, 15b ... Light receiving element, 30 ... Lamp.

Claims (3)

[Claims] 1. The brightness of the lamp (30) is adjusted by adjusting the current flowing through the lamp (30) based on the operation amount of a knob (4) rotatably supported by the case (2). A knob operation amount detector for a vehicle light control device according to claim 1, wherein the case (2) supports a disk (7) whose amount of light transmitted or reflected by the rotation thereof changes, and the disk (7) is The disc is made rotatable by operating a knob (4), and a photo interrupter (15) including a pair of light emitting diodes (15a) and a light receiving element (15b) is arranged on the peripheral edge of the disc (7). (7)
A knob operation amount detector for a vehicle light control device, which detects a change in light amount by rotating the. 2. The knob operation amount detector for a vehicle light control device according to claim 1, wherein the disk (7) is formed with slits (10) of which widths are varied along the circumferential direction thereof. A pair of light emitting diodes (1) facing each other across the slit (10)
5a) and a light receiving element (15b) are arranged in the photo interrupter (15), and the light emitting diode (15a) is provided.
Knob operation of a vehicle light control device for detecting a change in the amount of light emitted from the device through the slit (10) by the rotation of the disk (7) and receiving the light amount by the light receiving element (15b) Quantity detector. 3. A voltage (V) corresponding to the amount of light detected by the knob operation amount detector of the vehicle light control device according to claim 2.
a waveform shaping circuit section (23) for shaping a triangular wave (Vb) of a predetermined frequency generated by the oscillation circuit section (21) based on c) into a pulse wave (Vd) having a duty corresponding to the voltage (Vc). A dimmer circuit for a vehicle dimmer including a load drive circuit section (24) for flowing a current corresponding to a pulse wave (Vd) shaped by the waveform shaping circuit section (23) to the lamp (30) .