DIAL OPERATING APPARATUS

Abstract: When a knob dial 18 is turned on, a predetermined LED 15c to 15e corresponding to a rotational position of the knob dial 18 is turned on. Then, a beam of light is supplied to a predetermined indicator lens 29a to 29f via a predetermined light path 30, and the indicator lens 29a to 29f can be illuminated. In this structure, the optical path 30 is formed into a sector-shape. Therefore, even if the knob dial 18 is set at an intermediate position, the beam of light emitted from LED 15c to 15e is supplied to the indicator lens 29a to 29f via the optical path 30. Accordingly, the indicator lens 29a to 29f can be illuminated to the utmost.

Description: The present invention relates to a dial operation device having a structure of informing an operator of a rotational position of a knob dial when a plurality of display sections provided in the knob dial are selectively illuminated. 2. Technical Background Fig. 7 is a view showing a conventional structure of the above dial operation device. In this structure, a knob base 2 is fixed onto a printed circuit board 1. A knob dial 3 is attached onto an outer circumferential surface of this knob base 2. This knob dial 3 is provided with a plurality of linear light paths 3a. In the knob dial 3, there are provided a plurality of display sections 4 arranged at one end portion of each light path 3a, and these display sections 4 transmit light. On the printed wiring board 1, there are provided a plurality of light sources 5 which are located on a rotational locus of the display section 4. When the knob dial 3 is rotated for operation along an outer circumferential surface of the knob base 2, electricity is supplied to a predetermined light source 5 according to a rotational position of the knob dial 3, so that light can be supplied to a predetermined display section 4 via a predetermined light path 3a. Then, the predetermined display section 4 is illuminated. When a plurality of marks 2a on the knob base 2 are selectively indicated, a -rotational condition of the knob dial 3 is informed to an operator. However, the following problems may be encountered in the above conventional structure. When the knob dial 3 is set at an intermediate position at which the display section 4 and the light source 5 are not opposed to each other, a beam of projection light sent from the light source 5 is intercepted by the knob dial 3. Therefore, no light is supplied to the display section 4. Therefore, light can not be supplied to the display sections 4 in the middle of rotation of the knob dial 3. SUMMARY OF THE INVENTION The present invention has been accomplished in view of the above circumstances. It is an object of the present invention to provide a dial operation device capable of illuminating a display section to the utmost even in the middle of rotation of the knob dial. A dial operation device described in claim 1 comprises: a knob dial to be rotated for operation; a plurality of display sections capable of transmitting light, arranged in the knob dial; a plurality of light sources arranged on rotational loci of the plurality of display sections; a control unit for selectively turning on a light source in the plurality of light sources according to a rotational position of the knob dial; and a plurality of light paths for supplying light, which has been projected by the light sources, to the display sections, arranged in the knob dial, wherein these light paths are formed into a substantial sector-shape, the width of which is extended from the light exit to the light entrance. According to the above means, the light path is formed into a substantial sector-shape, and width of the light path is extended from the light exit to the light entrance. Due to the above structure, even if the knob dial is set at an intermediate position, a beam of projection light sent from the light source is projected into the light entrance except for an instant at which a wall section located between the light paths is opposed to the light source. Therefore, the beam of light can be supplied to the display section via the light path, so that the display section can be illuminated to the utmost. In the dial operation device described in claim 1, the control unit operates in such a manner that when the knob dial starts being rotated, a light source corresponding to the next rotational position is turned on while a light source corresponding to the rotational position of the dial knob is kept to be turned on. According to the above means, when the knob dial starts being rotated, a light source corresponding to the rotational position of the knob dial is turned on, and a light source corresponding to the next rotational position of the knob dial is turned on. Therefore, a beam of projection light sent from the light source corresponding to the next rotational position is supplied to the display section via the light path. Accordingly, the display section corresponding to the next rotational position of the knob dial is illuminated, and a rotational direction of the knob dial is informed. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a first embodiment of the present invention, that is, Fig. 1 is a perspective view showing a knob dial; Fig. 2 is a front surface view showing a heater controller; Fig. 3 is a transversely cross-sectional view showing the heater controller; Fig. 4 is a front view showing a printed wiring board; Fig. 5 is an exploded perspective view showing the heater controller; Fig. 6 is a view corresponding to Fig. 5 in which a second embodiment of the present invention is shown; and Fig. 7 is a view corresponding to Fig. 1 in which a conventional example is shown. THE MOST PREFERRED EMBODIMENT Referring to Figs. 1 to 5, the first embodiment of the present invention will be explained as follows. In this connection, this embodiment is a case in which the present invention is applied to a heater controller of an automobile, and this heater controller is attached onto an instrument panel of the automobile. As shown in Fig. 3, there is provided a bezel 32 made of synthetic resin. This bezel 32 is formed into a rectangular box-shape, the rear surface of which is open. A printed wiring board 12 is attached to the bezel 32 with screws, and a rear opening of the bezel 32 is covered with a printed wiring board 12 and a cover 11. As shown in Fig. 5, holders 13, 13 made of synthetic resin are attached onto the front surface of the printed wiring board 12. As shown in Fig. 1, each holder 13 has six partition walls 13a which are integrated with the holder 13. Only four partition walls 13a are shown in Fig. 5. Between the partition walls 13a, there is formed an LED accommodating section 13b. As shown in Fig. 4, two common circuit patterns 14, which are formed into an arc-shape, are formed on the front surface of the printed wiring board 12. As shown in Figs. 2 and 5, LEDs 15a to 15e corresponding to light sources are accommodated in five LED accommodating sections 13b of each holder 13. One of the terminals of each LED is connected to the common circuit pattern 14. As shown in Fig. 4, on the front surface of the printed wiring board 12, there are provided five power source circuit patterns 16 which are located in an outer circumferential section of each common circuit pattern 14. The other terminal of each LED is connected to the power source pattern 16. Electricity is supplied to LEDs 15a to 15e via the common circuit pattern 14 and the power source circuit pattern 16. Knob bases 17, 17 shown in Fig. 5 are made of synthetic resin. A cylindrical section 17a is integrally formed in each knob base 17. Each cylindrical section 17a corresponds to a moderation member and has a hexagonal cross-section as shown in Fig. 2. As shown in Fig. 3, there is formed a hole 12a at the center of the holder 13 on each printed wiring board 12. A screw is inserted into the hole 12a from the rear side. This screw 17b is screwed into the cylindrical section 17a. Due to the foregoing, the knob bases 17, 17 are fixed onto the printed wiring board 12. As shown in Fig. 5, a substantially-cylindrical knob dial 18 made of synthetic resin is pivotally engaged on an outer circumferential surface of each knob base 17. On an inner circumferential surface of the knob dial 18, there are formed three grooves not shown in the drawing. In the knob dial 18, there is accommodated a cylindrical knob body 19 made of synthetic resin. On an outer circumferential surface of the knob body 19, three protrusions 19a are integrally formed as shown in Fig. 5. The three protrusions 19a of the knob body 19 are engaged with the grooves of the knob dial 18. Therefore, when the knob dial 18 is rotated for operation, torque is transmitted to the knob body 19 via the three protrusions 19a, and the knob body 19 is integrally rotated. In this connection, as shown in Fig. 3, a plurality of spherical sections 21a are formed on a lower surface of each knob dial 18 and on a lower surface of each knob body 19. Due to the above structure, when each knob dial 18 is rotated for operation, the plurality of spherical sections 21a slide on the printed wiring board 12. As shown in Fig. 2, a leaf spring 22 corresponding to the spring member is accommodated in each knob body 19. Each leaf spring 22 is bent and formed into a triangle. In each leaf spring 22, there are formed three engaging sections 22a. As shown in Fig. 5, there are formed three grooves 19b on an inner circumferential surface of each knob body 19. The engaging sections 22a of the leaf spring 22 are inserted into the three grooves 19b of each knob body 19. Due to the above structure, when each knob dial 18 is rotated for operation, the leaf spring 22 is rotated integrally with the knob body 19. As shown in Fig. 2, three surfaces of each leaf spring 22 come into surface-contact with predetermined three surfaces of the cylindrical section 17a. Therefore, when each knob dial 18 is rotated and the leaf spring 22 is operated according to the rotation of the knob dial 18, the leaf spring 22 is pushed and deflected by three corners of the cylindrical section 17a. After that, the three corners of each cylindrical section 17a get over the leaf spring 22 and engage with three new surfaces, so that the rotation of each knob dial 18 can be regulated again. Accordingly, each knob dial 18 can be positioned at the interval of 60°. Further, each time the corners of the cylindrical section 17a get over the leaf spring 22 at the interval of 60°, it is possible to provide a feeling of moderation. As shown in Fig. 3, a contact 23 located on the outer circumference is screwed onto a rear surface of each knob dial 18. As shown in Fig. 5, each contact 23 has contact points 23a to 23d. The contact points 23a, 23b on the outer circumferential side come into contact with the common circuit pattern 14, the shape of which is an arc as shown in Fig. 4. On the front surface of the printed wiring board 12, there are provided first detection circuit patterns 24a to 24e which are located on the inner circumferential section of each common circuit pattern 14. When each knob dial 18 is rotated for operation, the contact point 23c of each contact 23 comes into the detection circuit pattern 24a to 24e according to the rotational position of the knob dial 18. Due to the foregoing, the predetermined detection circuit pattern 24a to 24e can be selectively continued to the common circuit pattern 14, and a continuation signal is outputted from the predetermined detection circuit pattern 24a to 24e. In this connection, the contact point 23b of each contact 23 is a dummy contact point which is provided for adjusting the mechanical balance. ECU (not shown) corresponding to a control unit is mounted on an automobile. This ECU is mainly composed of a microcomputer and operated as follows. A rotational position of each knob dial 18 is detected according to the detection circuit pattern 24a to 24e from which a continuation signal is outputted. A hot air or cold air blowing position of air control is changed over according to a rotational position of the knob dial located on the left, and a quantity of blowing control air is changed over according to a rotational position of the knob dial 18 located on the right. At the same time, electricity is supplied to a predetermined LED 15a to 15e via the common circuit pattern 14 and the power supply circuit pattern 16, so that light can be emitted from the predetermined LED 15a to 15e. As shown in Fig. 2, there are provided a plurality of marks 25 indicating a blowing position of hot air on the front surface of the knob base 17 located on the left, and there are provided a plurality of marks 26 indicating a quantity of blowing hot air on the front surface of the knob base 17 located on the right. These marks 25, 26 are formed on the knob base 17 by means of laser beam machining and have a property of light transmission. As shown in Fig. 3, there is provided a light guide 27 at the rear of the printed wiring board 12 in the cover 11. As shown in Fig. 4, there are provided openings for illumination at the rear of the marks 25, 26 on the printed wiring board 12. In the light guide 27, there are provided protrusions 27a at the rear of the openings 12b for illumination. As shown in Fig. 3, there are provided a plurality of lamps 28 on the rear surface of the printed wiring board 12. These lamps 28 are positioned in the light guide 27. When the plurality of lamps 28 are supplied with electricity by the controlling operation of ECU, light is emitted from the protrusions 27a so that the marks 25, 26 can be illuminated via the openings 12b for illumination. As shown in Fig. 1, an indicator lens 29a to 29f is embedded at a front end portion on a circumferential wall of each knob dial 18. These indicator lenses 29a to 29f correspond to- the display sections. LEDs 15a to 15e are positioned at the rear of the indicator lenses 29a to 29f, that is, LEDs 15a to 15e are positioned on the locus of rotation. Therefore, as shown in Fig. 2, under the condition that the knob dials 18 are positioned, five predetermined indicator lenses in the indicator lenses 29a to 29f are opposed to LEDs 15a to 15e. In this connection, the indicator lenses 29a to 29f are formed on the knob dials 18 by means of two color formation. As shown in Fig. 1, there are provided six light paths 30 on the circumferential wall of each knob dial 18. Each light path 30 connects a light entrance 30a, which is open via a rear surface of the knob dial 18, with a light exit 30b which is communicated with the indicator lens 29a to 29f. Each light path 30 is formed into a sector-shape in which width is gradually extended from the light exit 30b to the light entrance 30a. In this connection, reference numeral 30c is a light shielding wall section located between the light paths 30. Under the condition that a position of each knob dial 18 is regulated, each light shielding wall section 30c is opposed to a partition wall 13a of the holder 13. Accordingly, a beam of light projected from a predetermined LED 15a to 15e passes through the light exit 30a and the light entrance 30b and is supplied to a predetermined indicator lens 29a to 29f. Due to the foregoing, the predetermined indicator lens 29a to 29f emits light. Therefore, a plurality of marks 25, 26 are selectively indicated. In accordance with that, a hot air blowing position and a quantity of hot air to be blown out by the knob dial are informed to a driver. As shown in Fig. 4, on the front surface of the printed wiring board 12, there are provided second detection circuit patterns 31 a1 , 31 a2 to 31 e1 , 31 e2 which are located on an inner circumference of the first detection circuit patterns 24a to 24e. Under the condition that a position of each knob dial 18 is regulated, the contact point 23d of the contact 23 is located in a gap between the detection circuit patterns 31 a1 , 31 a2 to 31 e1 31 e2 as shown by two-dotted chain lines. Accordingly, when each knob dial 18 is rotated for operation, the contact point 23d of the contact 23 comes into contact with the detection circuit pattern 31 a1 , 31 a2 to 31 e1 , 31 e2 according to the rotational direction of the knob dial 18. Therefore, the detection circuit pattern 31 a1 , 31 a2 to 31 e1 , 31 e2 can be selectively continued to the common circuit pattern 14. Then, as described later, ECU judges a rotational direction of each knob dial 18 according to the detection circuit pattern 31 a1 , 31 a2 to 31 e1 , 31 e2 from which a continuity signal has been outputted. The bezel 32 shown in Fig. 5 is made of synthetic resin. As shown in Fig. 3, a plurality of engaging holes 32a are formed on a side plate of the bezel 32. In this case, only one engaging hole 32a is illustrated in the drawing. A plurality of claws 11a are integrally formed on a side plate of the cover 11. In this case, only one claw 11a is illustrated in the drawing. When the bezel 32 is pushed onto the outside of the cover 11, each engaging holes 32a are engaged with the claw 11a, so that the bezel 32 can be attached to the cover 11, and the front surface of the printed wiring board 12 is covered with the bezel 32. In this connection, as shown in Fig. 5, there are formed two circular openings 32b in the bezel 32. As shown in Fig. 3, each knob dial 18 protrudes from the opening 32b onto the front surface side. As shown in Fig. 5, on the front surface of the printed wiring board 12, there is provided a base 33 which is arranged between holders 13. In the uppermost portion of this base 33, there are provided rubber contact points 34a, 34b to turn on and off the defrosting mode in which controlled air is blown out onto a windshield. In the middle portion of this base 33, there are provided rubber contact points 34a, 34b to turn on and off the REC mode in which air is circulated in a chamber. In the lowermost portion of this base 33, there are provided rubber contact points 34a, 34b to turn on and off an air conditioner. In the bezel 32, there is formed a rectangular opening 32c. Into this rectangular opening 32c, three operation knobs 35 are attached as shown in Fig. 2. When each knob 35 is pushed for operation, ON-signal is outputted from the rubber contact points 34a and 34b. Each operation knob 35 is provided with an indicator lens 35a. As shown in Fig. 3, on the printed wiring board 12, there is provided an LED 35b which is arranged in each operation knob 35. According to the operating condition of the operation knob 35, ECU turns on and off LED 35b, so that each indicator lens 35a can be turned on and off. Therefore, a driver is informed of the operating condition (defrosting mode, REC mode and setting condition of the air conditioner) of each operation knob 35. As shown in Fig. 2, on the right of the bezel 32, there is provided a knob dial 36 which is pivotally attached. According to a rotational position of the knob dial 36, ECU adjusts a temperature of controlled air. In the bezel 32, there is provided an operation key 36a which is arranged inside the knob dial 36. When ECU detects an operation in which the operation key 36a is pushed, the automatic control mode is turned on and off. In the automatic control mode, a blowing position of controlled air and a quantity of controlled air can be automatically changed over. At the same time, when electricity is selectively supplied to LED 15a to 15e irrespective of the rotational position of each knob dial 18, light is emitted from a predetermined indicator lens 29a to 29f via the light entrance 30a and light exit 30b. Due to the foregoing, a changeover condition in which a position of blowing air and a quantity of blowing air are changed over can be informed to a driver. In the bezel 32, there are provided panels 37a and 37b. On the panels 37a and 37b, there are respectively provided indicator lenses 38a and 38b. When LED (not shown) is turned on and off by ECU, the indicator lenses 38a, 38b are turned on and off. Therefore, the operating condition (setting condition of the automatic control mode) of the operation key 36a can be informed to the driver. Next, the action of the above arrangement will be explained below. After the automatic control mode of an air blowing position and the automatic control mode of a quantity of controlled air have been turned off, each knob dial 18 is rotated for operation. Due to the above operation, ECU conducts controlling so that electricity can be supplied to LED 15a to 15e according to the rotational position of each knob dial 18 and a predetermined indicator 29a to 29f can be turned on. In accordance with that, a plurality of marks 25, 26 are selectively indicated. Due to the foregoing, the driver is informed of a rotational condition (hot air blowing position and quantity of hot air) of each knob dial 18. At the same time, while electricity is being supplied to LED 15a to 15e according to the rotational position of the knob dial 18, electricity is supplied to an adjacent LED 15a to 15e in the rotational direction of the knob dial 18. Due to the foregoing, the rotational direction of the knob dial 18 is informed to the driver. For example, as shown by two-dotted chain lines in Fig. 4, before the operation of each knob dial 18, the contact point 23c of each contact 23 comes into contact with the first detection circuit pattern 24c. Under the above condition, the detecting circuit pattern 24c and the common circuit pattern 14 are electrically continued to each other. Therefore, a continuation signal is outputted from the detecting circuit pattern 24c. Accordingly, when ECU conducts controlling so that electricity can be supplied to LED 15c in Fig. 2, a beam of light is supplied to the indicator lens 29c via the light entrance 30 and the light exit 30b, and light is emitted from the indicator lens 29c. When the knob dial 18 is rotated for operation in the direction of arrow A under the above condition, the contact point 23d of the contact 23 comes into contact with the second detecting circuit pattern 31 c2 in Fig. 4, and a continuity signal is outputted from the second detecting circuit pattern 31 c2 . Then, ECU judges that a rotational operation in which the knob dial 18 is rotated in the direction of arrow A has been started. Therefore, in Fig. 2, electricity is supplied to LED 15d which is adjacent to LED 15c in the direction of arrow A, and LED 15c and LED 15d are simultaneously turned on. When LED 15c and LED 15d are turned on, a beam of projection light sent from LED 15c is supplied to the indicator lens 29c via the light entrance 30a and the light exit 30b. Therefore, the light emitting condition of the indicator lens 29c can be kept. At the same time, a beam of projection light sent from LED 15d is supplied to the indicator lens 29d via the light entrance 30a and the light exit 30b. Therefore, light is emitted from the indicator lens 29d. After that, the contact point 23c of the contact 23 comes into contact with the first detecting circuit pattern 24d in Fig. 4, and a continuity signal is outputted from the first detecting circuit pattern 24d. Then, ECU turns off LED 15c in Fig. 2. Then, a beam of projection light sent from LED 15d is supplied to the indicator lens 29c via the light entrance 30a and the light exit 30b. Therefore, only the indicator lens 29c emits light. In the above embodiment, when the leaf spring 22 is engaged with three surfaces of the cylindrical section 17a, the rotation of the knob dial 18 is regulated. Therefore, when the knob dial 18 is operated and the leaf spring 22 is rotated, the leaf spring 22 is pushed by three corners of the cylindrical section 17a and bent in the same direction as that of pushing. For the above reasons, the rotational resistance of the knob dial 18 is reduced, and an operation feeling of the knob dial 18 becomes light. It is possible to prevent the operation feeling from growing heavy especially at an intermediate position. In this embodiment, the light path 30 is formed into a sector-shape in which width of the light path 30 is extended from the light exit 30b to the light entrance 30a. Therefore, even when the knob dial 18 is set at an intermediate position, that is, even when the position of the knob dial 18 is not regulated, a beam of projection light sent from LED 15a to 15e is projected into the light entrance 30a except for an instant at which the light shielding wall section 30c is opposed to LED 15a to 15e. Then, the beam of projection light is supplied to the indicator lens 29a to 29f via the light path 30. Therefore, the indicator lens 29a to 29f can be illuminated to the utmost. When the rotational operation of the knob dial 18 is started, while electricity is being supplied to LED 15a to 15e according to the rotational position of the knob dial 18, LED 15a to 15e adjacent to it in the rotational direction of the knob dial 18 is supplied with electricity. Therefore, the rotational direction of the knob dial 18 is informed to a driver, and the dial operation device becomes more handy. When the leaf spring 22 is engaged on three surfaces of the cylindrical section 17a, rotation of the knob dial 18 is regulated. Therefore, when the leaf spring 22 is rotated according to the operation of the knob dial 18, the leaf spring 22 is pushed by three corners of the cylindrical section 17a and deflected in the direction. Due to the foregoing, rotational resistance of the knob dial 18 is reduced, and a feeling of operation of the knob dial 18 becomes light. It is possible to prevent a feeling of operation from growing heavy especially at an intermediate position. Next, referring to Fig. 6, the second embodiment of the present invention will be explained below. In this connection, like reference characters are used to indicate like parts in the first and the second embodiment, and the explanations are omitted here. Only parts of the second embodiment different from the first embodiment will be explained as follows. In the knob body 19 arranged on the left, there are provided two wire springs 39 which correspond to spring members. In the knob body 19 arranged on the right, there is provided one wire spring 39 which corresponds to a spring member. Each wire spring 39 described above is bent into a triangle. In each wire spring 39, there are formed three engaging sections 39a. Each engaging section 39a is inserted into a groove 19b of the knob body 19. Rotation of the knob dial 18 arranged on the left is regulated when two wire springs 39 are engaged with three surfaces of the cylindrical section 17a. Rotation of the knob dial 18 arranged on the right is regulated when one wire spring 39 is engaged with three surfaces of the cylindrical section 17a. In the above embodiment, when the knob dial 18 arranged on the left is rotated for operation, two wire springs 39 are rotated. Then, the wire springs 39 are pushed against three corners of the cylindrical section 17a and deflected in the direction. After that, when three corners of the cylindrical section 17a get over the wire springs 39 and new three surfaces are engaged with two wire springs 39, rotation of the knob dial 18 is regulated. Due to the foregoing, rotational resistance of the knob dial 18 is reduced. Accordingly, a feeling of operation of the knob dial 18 becomes light, and rotation of the knob dial 18 is prevented from stopping in the middle of operation. Further, different from the first embodiment in which the leaf spring 22 is used as a spring member, the wire spring 39 is used in the second embodiment. Therefore, height of the knob dial 18 can be decreased. When the knob dial 18 arranged on the right is rotated, one wire spring 39 is rotated. Then, the wire spring 39 is pushed against three corners of the cylindrical section 17a and bent in the direction. After that, when three corners of the cylindrical section 17a get over the wire springs 39 and new three surfaces are engaged with the wire springs 39, rotation of the knob dial 18 is regulated. Due to the foregoing, rotational resistance of the knob dial 18 is reduced. Accordingly, a feeling of operation of the knob dial 18 becomes light, and rotation of the knob dial 18 is prevented from stopping in the middle of operation. Further, since the wire spring 39 is used as a spring member, height of the knob dial 18 can be decreased. Two wire springs 39 are used for the knob dial 18 arranged on the left, and one wire spring 39 is used for knob dial 18 arranged on the right. Therefore, an intensity of the knob dial 18 arranged on the left is different from an intensity of the knob dial 18 arranged on the right. Accordingly, it is possible for a driver to distinguish between the two knob dials 18 by a feeling of operation. Therefore, the operation property of the knob dial 18 can be enhanced. In this connection, in order to make an intensity of the knob dial 18 arranged on the left to be different from an intensity of the knob dial 18 arranged on the right in the first embodiment described before, it is necessary to adjust a spring force by changing heights of both leaf springs 22. Therefore, it is necessary to carefully distinguish between both leaf springs 22 so as to attach them to the knob dials 18, which takes labor and time. In order to improve the above circumstances, the wire springs 39, the numbers of which are different from each other, are used for both knob dials 18. Therefore, it is unnecessary to carefully distinguish between both leaf springs 22 when they are attached to the knob dials 18. Accordingly, the assembling property can be enhanced. Unlike a case in which the leaf springs 22 of different types are manufactured, only one type wire spring 39 is used in this embodiment. Therefore, this embodiment is advantageous in that the number of parts can be reduced. In the above second embodiment, two wire springs 39 are accommodated in the knob body 19 arranged on the left, and one wire spring 39 is accommodated in the knob body 19 arranged on the right. However, it should be noted that the present invention is not limited to the above specific embodiment. The number of the wire springs 39 may be adjusted if necessary. In the above second embodiment, wire springs 39 are accommodated in both knob bodies 19. However, it should be noted that the present invention is not limited to the above specific embodiment. For example, when both the leaf spring 22 and the wire spring 39 are accommodated, intensities of forces to operate both knob dials 18 may be adjusted. In the above first and the second embodiment, the second detection circuit patterns 31 a1 , 31 a2 to 31 e1 , 31 e2 for detecting the rotational directions of the knob dials 18 are formed on the printed wiring board 12. However, it should be noted that the present invention is not limited to the above specific embodiment. For example, the second detection circuit patterns 31 a1 , 31 a2 to 31 e1 , 31 e2 may be abolished. In this structure, the contact point of each contact 23 may be also abolished. In the above first and the second embodiment, the cylindrical section 17a is fixed to the holder 13, and the leaf spring 22 and the wire spring 39 are rotated integrally with the knob dial 18. However, it should be noted that the present invention is not limited to the above specific embodiment. For example, the leaf spring 22 or the wire spring 39 may be fixed to the holder 13, and the cylindrical section 17a may be rotated integrally with the knob dial 18. In the above first and the second embodiment, the cylindrical section 17a, the cross-section of which is hexagonal, the triangular leaf spring 22 and the wire spring 39 are used and three surfaces of the cylindrical section 17a are engaged with the leaf spring 22 and the wire spring 39. However, it should be noted that the present invention is not limited to the above specific embodiment. For example, a linear leaf spring and wire spring may be used, and one surface of the cylindrical section 17a may be engaged with the leaf spring and the wire spring. In the above first and the second embodiment, a rotational position of the knob dial 18 is regulated at the regular interval of 60°. However, it should be noted that the present invention is not limited to the above specific embodiment. For example, a rotational position of the knob dial 18 may be regulated at the regular interval of 30°. In this structure, a cross-section of the cylindrical section 17a may be formed into a dodecagon, and the leaf spring 22 and the wire spring 39 may be formed into hexagons. In the above first and the second embodiment, the present invention is applied to a heater controller of an automobile. However, it should be noted that the present invention is not limited to the above specific embodiment. The essential point is that the present invention can be applied to all dial operation devices having rotational knob dials. As can be understood from the above explanations, the dial operation device of the present invention can provide the following effects. According to the means described in claim 1, the light path is formed into a sector-shape in which width of the light path is extended from the light exit to the light entrance. Due to the above structure, even if the knob dial is set at an intermediate position, a beam of projection light can be supplied to the display section from the light source via the light path. Accordingly, the display section can be illuminated to the utmost. According to the means described in claim 2, while the light source corresponding to the rotational position of the knob dial is being turned on, the light source of the next rotational position is turned on. Therefore, the display section corresponding to the next rotational position of the knob dial is illuminated. Accordingly, it is possible to inform a rotational direction of the knob dial to an operator.

Claims: A dial operation device comprising: a knob dial (18) to be rotated for operation; a plurality of display sections (25) capable of transmitting light, arranged in the knob dial; a plurality of light sources (15) arranged on rotational loci of the plurality of display sections; a control unit for selectively turning on a light source in the plurality of light sources according to a rotational position of the knob dial; and a plurality of light paths (30) for supplying light, which has been projected by the light sources, to the display sections, arranged in the knob dial, wherein these light paths are formed into a substantial sector-shape, the width of which is extended from a light exit to a light entrance. The dial operation device described in claim 1, wherein the control unit operates in such a manner that when the knob dial (18) starts being rotated, a light source corresponding to the next rotational position is turned on while a light source corresponding to the rotational position of the dial knob is kept to be turned on.

Inventors: ISHIGURO KAZUYOSHI, ISHIGURO, KAZUYOSHI, ISHIGURO, Kazuyoshi, KK Tokai-Rika-DenkiSeisakusho
Applicants: TOKAI RIKA CO LTD, KABUSHIKI KAISHA TOKAI-RIKA-DENKI-SEISAKUSHO
Application year: 1997
Main classification: H01H19
IPC codes: H01H19, H01H9