Illuminated knob device

An object of the present invention is to improve the manipulating property of a rotary knob device. According to the present invention, a variable resistor and switch has an inner unrotatable shaft, and an outer rotatable shaft. A first manipulation member having a light guide portion, a light bending portion and a luminous portion is coupled to the inner shaft. A sign indicative of the method of manipulation of the resistor and switch, and a sign indicative of the function thereof are provided on the luminous portion. The luminous portion is illuminated to make the signs clearly visible. The signs provided on the first manipulation member fitted on the inner unrotatable shaft are illuminated with the luminous portion of the member so that the signs are shown at a high luminance to improve the manipulating property of the knob device.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an illuminated knob device for audio 
equipment of a motor vehicle or for the like. 
2. Description of the Background Art 
FIG. 2 is a sectional view of a conventional illuminated knob device 
disclosed in Unexamined Japan Utility Model Application No. 24232/91. The 
device includes an illuminated knob 11, the rotary shaft 12a of a variable 
resistor and switch 12, and a light emission diode 13. The knob 11 has a 
light guide portion 11a, a light bending portion 11b, and an outer 
luminous portion 11c, and is fitted on the rotary shaft 12a. The diode 13 
is attached to the resistor and switch 12 mounted on a printed circuit 
board 14. Rays of light are emitted from the diode 13, transmitted through 
the light guide portion 11a, reflected by the light bending portion 11b, 
and irradiated upon the outer luminous portion 11c to illuminate it. 
Since the illuminated knob 11 is rotated synchronously with the rotary 
shaft 12a, only one point can be illuminated in the outer luminous portion 
11c. This is a problem. Since the light emission diode 13 is located in a 
fixed position, the luminance of the luminous portion 11c varies from 
rotation angle to rotation angle. This is also a problem. 
SUMMARY OF THE INVENTION 
The present invention was made in order to solve the above-mentioned 
problems. Accordingly, it is an object of the invention to provide an 
illuminated knob device with is improved manipulating properties and on 
the luminous portion of which the function of a variable resistor and 
switch and the method of manipulation thereof can be clearly shown by 
illuminating the portion. 
The device includes an inner unrotatable shaft and an outer rotatable shaft 
of the variable resistor and switch, a first manipulation member fitted on 
the inner unrotatable shaft and having the luminous portion provided with 
signs for showing the function of the resistor and switch and the method 
of manipulation thereof, and a second manipulation member fitted on the 
outer rotatable shaft. 
In the illuminated knob device provided in accordance with the present 
invention, the manipulation method indicating sign and the function 
indicating sign are shown on the design surface of the luminous portion of 
the first manipulation member fitted on the inner unrotatable shaft of the 
variable resistor and switch. The resistor and switch can be manipulated 
with the second manipulation member fitted on the outer rotatable shaft of 
the resistor and switch. 
Further scope of applicability of the present invention will become 
apparent from the detailed description given hereinafter. However, it 
should be understood that the detailed description and specific examples, 
while indicating preferred embodiments of the invention, are given by way 
of illustration only, since various changes and modifications within the 
spirit and scope of the invention will become apparent to those skilled in 
the art from this detailed description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
An embodiment of the present invention is hereafter described with 
reference to the drawings attached hereto. 
FIG. 1(A) shows an illuminated knob device. The device includes a first 
manipulation member 1, the inner unrotatable shaft 2a and outer rotatable 
shaft 2b of a variable resistor and switch 2, a second manipulation member 
3, light sources 4, and a light guide 6. The first manipulation member 1 
has a light guide portion 1a, a light bending portion 1b and a luminous 
portion 1c integrally formed together, and is fitted on the inner 
unrotatable shaft 2a of the resistor and switch 2. The second manipulation 
member 3 surrounds the first manipulation member 1, and is fitted on the 
outer rotatable shaft 2b of the resistor and switch 2. The light sources 4 
are attached to a printed circuit board 5, and put in the light guide 6. 
The second manipulation member 3 has a transparent portion 3a formed 
integrally with the other portion of the member. The reference numerals 7 
and 8 designate operation characters and function characters which are 
provided on the outer surface of the first manipulation member 1. 
Rays of light are emitted from the light sources 4 into the light guide 6 
so that the rays of light pass through the light guide 6 to reach the 
second manipulation member 3. Succeedingly, the rays of light are 
reflected by the light bending portion 1b of the first manipulation member 
1 so that the rays of light travel through the light guide portion 1a and 
reach the luminous portion 1c to illuminate it to make the characters 7 
and 8 clearly visible, To whatever angle the outer rotatable shaft 2b 
coupled to the second manipulation member 3 is rotated therewith, the rays 
of light are transmitted through the transparent portion 3a of the member 
so that the luminous portion 1c of the first manipulation member 1 is 
illuminated by the rays of light. 
Since the device includes only one light bending portion 1b, the quantity 
of rays of light which are damped to not reach the luminous portion 1c is 
reduced to heighten the luminance thereof. Besides, some rays of light can 
be taken out from the light guide 6 to illuminate the second manipulation 
member 3 to make the presence thereof clearly visible. 
An illuminated knob device provided in accordance with the present 
invention includes the mutually different shafts of a variable resistor 
and switch, a first manipulation member having a light guide portion, and 
a second manipulation member having a transparent portion, so that the 
method of manipulation of the resistor and switch and the function thereof 
can be clearly shown. It is thus attained to much improve the manipulating 
property of the device and make the design thereof novel. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the invention, and all such modifications as 
would be obvious to one skilled in the art are intended to be included 
within the scope of the following claims.