JPH09115388A - Rotational position detecting structure for rotary selector switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify and make compact the rotational position detecting structure of a rotary selector switch. SOLUTION: A function selector dial 10 is rotatably fitted to an upper lid case 37, and an encoding board 34 is fitted to the rear surface of the dial 10 for integrated rotation therewith. In addition, an intermediate track is formed out of a resistor on the lower surface of the encoding board 34, and tracks at both sides of the intermediate track are formed out of a ring pattern of electrodes along a concentric circle. Furthermore, a brush member 35 held on a support plate 354 is kept in contact with three armatures 351 to 353 under pressure at a position under the encoding board 34. In this case, the armatures 351 to 353 are bonded in a laminar form via insulation sheets 44 and 45, and formed to have projections 351a to 353a respectively exposed from a notch 41 and square holes 42 and 43. The armatures 351 to 353 are secured to the lower surface of the support plate 354. with the projections 351a to 353a respectively kept in contact with the electrodes and the resistor under pressure for detecting partial voltage applied from the armature 352 pressed to the resistor across both electrodes, thereby detecting the rotational position of the function selector dial 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary changeover switch such as a dial switch of a camera, and more particularly to a structure for detecting a rotational position of a dial due to rotation.

[0002]

2. Description of the Related Art For example, in a camera, a dial switch is used as a switch for switching settings such as shutter speed, film sensitivity and exposure correction value, and selective settings such as a program shooting mode.

As shown in FIG. 10, a conventional dial switch is rotatable mainly on a disk-shaped encoder board 101 fixed to a camera body 200 and a tip of a rotary shaft 102 projecting from the center of the encoder board 101. And a brush 104 mounted between the dial 103 of the rotary shaft 102 and the encoder substrate 101 so as to rotate integrally with the dial 103.

On the surface of the encoder substrate 101, a plurality of electrode patterns 101a made of gold, copper or the like are formed concentrically for detecting rotational positions. On the other hand, the brush 1
Reference numeral 04 denotes an elastic member, and a plurality of strip-shaped press-contact pieces 104b press-contacted to the respective tracks of the electrode pattern 101a are provided in an obliquely downward direction at appropriate positions on the arm 104a. The pressure contact piece 104b has an electrode pattern 101a at the tip.
A protrusion 104c that serves as a contact point with the electrode pattern 101 is formed by its own bending force.
a.

The dial 103 has switching contents 103a displayed on its surface at a predetermined rotation angle, and is rotatable in both the clockwise direction and the counterclockwise direction at the predetermined angle pitch.

The brush 104 rotates integrally with the rotation of the dial 103, whereby the pressure contact piece 104a slides on the electrode pattern 101a. The electrode pattern in contact with the plurality of pressure contact pieces 104a changes depending on the rotating position of the dial 103.
The rotational position of 3 is detected. That is, if the number of tracks of the electrode pattern 101a is four, the contact / non-contact pattern of each press contact piece 104a with the electrode indicates 4-bit position information, and the dial 103 is rotated by decoding the 4-bit information. The position is detected.

[0007]

In the above-mentioned conventional dial switch, the brush 104 is pressed from its upper position above the encode substrate 101 by its own elastic force in a floating state, so that the support of the brush 104 is unstable. Therefore, it is difficult to uniformly press all the press contact pieces 104b to the encoder substrate 101. Further, since the soft and easily deformable brush 104 is directly attached to the rotary shaft 102, it is difficult to handle the brush 104 during assembly, and even if the press contact piece 104b is slightly deformed, the encoder board 101 and The contact position of is displaced, and erroneous detection is likely to occur.

Further, when the number of detection positions increases,
The electrode pattern 101a of the encoder substrate 101 becomes complicated and dense, and it becomes necessary to make the encoder substrate 101 large in order to secure a certain detection accuracy. Further, when the number of the pressure contact pieces 104b of the brush increases, each pressure contact piece 104b increases.
The number of signal lines externally connected to b is increased, the wiring process for these is complicated, and the entire dial switch 100 is enlarged.

The present invention has been made in view of the above problems, and provides a rotary position detecting structure for a rotary changeover switch, which is simple, small-sized, and capable of reliably detecting the rotary position.

[0010]

According to the present invention, a brush member slides relatively on a conductive pattern formed on a concentric circle with respect to a rotation axis of the rotary operation part by a rotation operation of the rotary operation part, In the rotary position detection structure of the rotary type changeover switch in which the rotational position of the rotary operation unit is detected from the contact position of the brush in the conductive pattern, the conductive pattern is formed on the back surface of the rotary operation unit, and the outermost and The brush member is composed of an endless electrode formed on the inner track and a C-shaped resistor formed on an intermediate track between the two tracks and having both ends connected to the inner track electrode and the outer track electrode, respectively. , A protrusion and a connecting portion to which the signal line is externally connected are formed on the tip end portion and the base end portion, respectively, and the track interval of the electrode pattern is formed on the intermediate portion. When arranged in parallel at intervals, the three band-shaped contact pieces in which the coupling portions that overlap each other project in the lateral direction with respect to the longitudinal direction are fixed by laminating the coupling portions with the insulating sheet. The protrusion of each contact piece is provided in a position below the rotation operation portion by pressing the projection of each contact piece against the electrode and the resistor, respectively (Claim 1).

According to the above construction, the brush members 1 to 3
The contact pieces are arranged in parallel at the same intervals as the rack intervals of the electrode pattern by overlapping and combining the connecting portions with an insulating sheet in a layered manner. By arranging the brush member below the electrode pattern so that the first to third contact pieces are aligned with the tangential direction of each track, the first to third contact pieces are arranged.
Each protrusion of the contact piece is pressed against the electrode on the innermost track, the resistor on the intermediate track, and the electrode on the outermost track of the electrode pattern.

When the third contact piece is grounded and a predetermined voltage V is applied to the first contact piece, the voltage V is applied from the second contact piece to the total resistance value r1 of the resistor and the first contact piece. Voltage Va = V · r2 / r divided by the resistance ratio with the resistance value r2 between the second contact pieces
1 is output.

When the rotating operation portion is rotated, the conductive pattern formed on the back surface of the operating portion is integrally rotated, whereby each contact piece of the brush member pressed against from the lower position of the rotating operation portion is relatively conductive pattern. Slide on. When the second contact piece slides on the C-shaped resistor, the resistance value R2 changes, and the second contact piece outputs the divided voltage Va corresponding to the rotational position of the rotary operation part. The rotation position of the rotation operation unit is detected from Va.

Therefore, when the rotation operating portion is stopped at a predetermined rotation position, the rotation position of the rotation operating portion is detected from the contact position of the brush member in the conductive pattern at that time.

Further, in the rotational position detecting structure of the rotary changeover switch, the brush member has an insulating support plate having three holes formed in parallel at the same spacing as the track spacing of the conductive pattern. Then, on the surface of the support plate opposite to the surface facing the conductive pattern, the contact pieces connected by the connecting portions may support the protruding portions of the contact pieces from the holes toward the conductive pattern side. (Claim 2).

According to the above structure, the three contact pieces connected to each other at the connecting portion are provided on the support plate with the projections of the contact pieces on the surface opposite to the surface of the support plate facing the conductive pattern. It is supported and fixed on the support plate by projecting from the hole to the conductive pattern side. Since each contact piece is fixed along one surface of the support plate except for the protruding portion, the mechanical and electrical strength of the brush member is increased.

Further, the connection portion of each contact piece of the brush member is arranged so that the connection portions of the adjacent contact pieces are on the opposite surfaces of the board to the signal line formed on the front and back surfaces of the board to be externally connected. , And each may be connected (claim 3).

According to the above construction, the first elements arranged in parallel are arranged.
-Each connection part of the third contact piece is connected to the corresponding signal line so that the adjacent connection parts are on the opposite surfaces of the substrate on which the signal lines are formed, so the connection space of each connection part is effective. It is utilized and contributes to miniaturization.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A rotary position detecting structure of a rotary type changeover switch according to the present invention will be described by taking a function selection dial of a camera as an example.

FIG. 1 is a front view of a camera equipped with the function selection dial, FIG. 2 is a rear view of the camera, FIG. 3 is a top view of the camera, and FIG. 4 is an internal structure of the camera. It is a schematic diagram.

The camera 1 is a small compact camera having a size substantially the same as the size of a business card, and has a retractable photographic lens unit 2 having a rectangular mirror copper in the front center of the camera body B.

The photographing lens unit 2 is completely stored in a predetermined retracted position in the camera body B when not photographing, and is extended to a photographing position protruding from the camera body B when photographing.

A finder objective window 3 and a photometric window 4 are provided above the photographing lens unit 2 on the front surface of the camera body B, and a distance measuring window 5 is adjacent to the finder objective window 3.
Is provided, and automatic focusing (AF) is provided adjacent to the photometric window 4.
Is provided for the auxiliary light emitting section 6. A finder optical system 30, a photometric element 31, and a distance measuring element 29 are provided on the back surfaces of the finder objective window 3, the photometric window 4, and the ranging window 5, respectively (see FIG. 4). Further, a flash window 7 and a light emitting window 8 for red-eye reduction / self-timer display are provided on the front side and the upper right side of the camera body B, and a flash lamp 33 and a lamp 32 are arranged on the back sides of these windows 7 and 8, respectively. It is installed (see Figure 4).

Further, as shown in FIG. 3, a release button 9 is provided at the left end of the upper surface of the camera body B when viewed from the front.
Is provided on the diagonally right upper side of the release button 9, and a function selection dial 10 for selecting various functions such as flash light emission and a self-timer is provided. A slide switch 11 for setting set values for various functions set by the function selection dial 10 at the boundary position between the upper surface and the front surface.
Is provided. The details of the rotational position detection structure of the function selection dial 10 will be described later.

Further, a display unit 19 made of an LCD (Liquid Crystal Display) is provided at the right end of the upper surface of the camera 1 as viewed from the front, and the display unit 19 is selected by the function selection dial 10. The required display regarding the function is made.

The present camera 1 has a flash lamp 33 forcibly emitting light, a red-eye reducing lamp 32 for emitting light, self-timer setting, film sensitivity (ISO sensitivity) setting, automatic focus adjustment (AF), manual focus adjustment (MF). And various functions such as exposure compensation settings can be set, and the function selection dial 1
The contents of the selection function are displayed on the peripheral portion of the surface of 0 with the symbol mark 10a at every predetermined pitch angle.

Various functions are selected and set by rotating the function selection dial 10 and aligning the symbol mark 10a with the alignment mark 18 displayed on the upper surface of the camera 1, and the contents displayed on the display unit 17 are confirmed. While operating the slide switch 11, desired functions and numerical values are set. For example, when the mark of the light emission arrow is selected, the slide switch 11 sets ON / OFF of the forced light emission of the flash lamp 33, and "+/-"
When the mark is selected, the slide switch 11 can set a plurality of exposure correction values in both positive and negative directions at a pitch of 0.5 (EV).

A button 17 provided between the function selection dial 10 and the slide switch 11 on the upper surface of the camera 1 is an AF reset button. In the camera 1, an AF mode and an MF mode can be selected by a function selection dial 10, and a plurality of preset focus positions can be set in the MF mode. The AF reset button 17 is a reset button for immediately switching from the focus position selection mode in the MF mode to the AF mode, and is a button in consideration of the operability in the "AF / M" function selection.

As shown in FIG. 2, an LCD display illumination button 12, a diopter adjustment dial 13, a viewfinder eyepiece window 14, a main switch 15 and a spot metering button 16 are provided from the left on the upper portion of the back surface of the camera 1. It is provided.

The LCD display illumination button 12 is a button for illuminating the display 19, and the diopter adjustment dial 1 is used.
Reference numeral 3 is a dial for adjusting the diopter of the finder. Further, the main switch 15 is a switch for turning on / off the main power source, and the spot metering button 16 is a button for instructing spot metering at the center of the photographing screen. In addition,
The camera 1 is capable of multi-photometry, and the spot photometry button 16 is an operation button in consideration of a case where spot photometry is intentionally required.

Further, inside the camera body B, as shown in FIG. 4, a horizontally long rectangular photographing screen frame 20 is provided at the rear position of the photographing lens unit 2.

At the left end of the camera body B, there is provided a cartridge storage chamber 21 for storing a film cartridge.
A main capacitor 22 for emitting the built-in flash is provided in the center at the right end, and a drive unit 24 including a motor 23 and a gear mechanism for transmitting the drive force of the motor 23 to each drive system is provided below the main capacitor 22. ing. In addition, a battery storage chamber 2 in which a power supply battery is stored at the bottom of the camera body B
5 are provided.

The driving force of the motor 23 is, for example, the driving shaft 2 of the sprocket 26 for winding the film.
7 and the rewinding reel 28 provided in the lower portion of the cartridge storage chamber 21, and the film is wound / rewound by driving the motor. In addition, the driving force of the motor 23 is also transmitted to the drive unit of the photographic lens unit 2 (not shown), and the motor drive drives the photographic lens unit 2 to and from the camera body B and performs AF control.

Next, the rotational position detecting structure of the function selection dial according to the present invention will be described.

FIG. 5 is a sectional view of the principal part taken along the line AA of FIG. The rotational position detection mechanism of the function selection dial 10 is composed of a disk-shaped encoder substrate 34 provided on the back surface of the function selection dial 10 and a brush member 35 that is pressed against the encoder substrate 34 from below.

The encoder board 34 is provided on the back surface of the upper lid case 37 to which the function selection dial 10 is rotatably mounted, and is attached to the lower end of the rotary shaft 36 of the function selection dial 10 which is penetratingly attached to the upper lid case 37. The function selection dial 10 and the function selection dial 10 are integrally rotatable.

As shown in FIG. 6, the encoder substrate 34 has an insulating substrate 342 and an encoding pattern 341 made of a conductive member formed on the lower surface of the insulating substrate 342. The encoding pattern 341 includes three ring-shaped patterns 341 a, 341 b, which are formed concentrically with respect to the rotation shaft 36.
The innermost and outermost track patterns 341a and 341c are endless ring electrodes made of a metal thin film such as gold or copper, and the middle track ring pattern 341b has inner rings at both ends. It is composed of a C-shaped resistor such as carbon connected to the electrode 341a and the outer ring electrode 341c.

On the other hand, the brush member 35 is mainly composed of a metal elastic member such as phosphor bronze which is pressed against the ring electrodes 341a and 341c and the C-shaped resistor 341b.
Book contact pieces 351, 353, 352 and these contact pieces 351 to
Section L made of an insulating member such as synthetic resin for supporting 353
It is composed of a character-shaped support plate 354.

FIG. 7 is an exploded perspective view showing the structure of the brush member. The support plate 354 attaches the brush member 35 to the camera 1.
Rectangular fixing portion 354a fixed to the housing 38 and the rectangular supporting portion 35 supporting the contact pieces 351 to 353.
4b, and a round hole 40 into which a fixing screw is fitted is formed at an appropriate position of the fixing portion 354a. Further, the support portion 354b is provided with a rectangular notch 41 at an appropriate position on the long side side portion 354c, and rectangular notches 41 and 43 having substantially the same size as the notch 41 are provided at a predetermined interval d. It is provided in parallel with 41. The distance d has substantially the same size as the distance d ′ between the three tracks of the encode pattern 341. Further, a square hole may be provided instead of the notch 41.

The contact piece 351 is in the form of a strip, has a protrusion 351a formed by bending in a U shape at the tip, and a connection 351b to which the signal line formed on the flexible substrate 39 is externally connected at the base. Are formed. The protrusion 351
The height of a is such that when the protrusion 351a is fitted into the notch 41 from the lower surface of the support portion 354b, the thickness t of the support portion 354b is projected from the surface of the support portion 354b.
It is set larger.

Further, at a proper position of the intermediate position, a rectangular connecting portion 35 is formed from the base end portion in the longitudinal direction to the right side with respect to the front end portion direction.
1c is projected vertically and in parallel. This joint 35
Reference numeral 1c is for arranging and connecting the contact pieces 351 to 353 in parallel with each other with the above-mentioned interval d, and a connecting hole 351d is formed at an appropriate position of the connecting portion 351c.

Similar to the contact piece 351, the contact pieces 352, 353 are formed with projections 352a, 353a at their distal ends and connection parts 352b, 353b at their base ends, and are connected to a predetermined intermediate position. Parts 352c, 353c
Are formed. The contact piece 35 in the contact piece 352
Distance from the base end of 2c and contact piece 35 in contact piece 353
The distance from the base end of 3c is the joint portion 3 of the contact piece 351.
It is the same as the distance D from the base end of 51c. Also,
The contact piece 353c of the contact piece 353 is vertically projecting from the base end portion in the longitudinal direction to the left side with respect to the tip end direction, and the contact piece 352c of the contact piece 352 extends from the base end portion in the longitudinal direction to the tip end direction. On the other hand, the connecting portions 351c, 352c, 353c are provided to project vertically in both left and right directions, and have substantially the same size.

In the contact pieces 351 to 353, the rectangular insulating sheets 44 and 45 having substantially the same size as the connecting portions 351c to 353c are connected to the connecting portions 351c and 352.
c and between the coupling portions 352c and 353c, respectively, and the coupling portions 351c to 353c are superposed and coupled in a layered manner.
The connecting portions 351b, 352b, 353b of 52, 353 are connected to the connecting electrodes 391, 392, 393 of the signal line formed on the connecting portion 390 of the flexible substrate 39 by soldering or the like.

The connecting portion 39 of the flexible substrate 39
The connection electrodes 391, 393 are formed on the front surface of 0 at the same intervals as the contact pieces 351 and 353, and the connection electrode 392 is formed on the back surface of the connection portion 390.
And the connection electrode 393.

On the other hand, the connecting portion 35 of the lowermost contact piece 353.
3b includes a connecting portion 351b of the contact piece 351 in a laminated connection state.
An upper step is provided to have the same height as
The connecting portion 352b of the intermediate contact piece 352 is provided with a downward step.

The connecting portion 39 of the flexible substrate 39 is provided between the connecting portions 351b and 353b and the connecting portion 352b.
0 is inserted, and the connection portions 351b, 352b, 353b are connected to the connection electrodes 391, 392, 393 respectively by soldering or the like.

As described above, the connecting portions 351c to 353c are provided with the connecting portions 351c to 353c, and these are connected to the insulating sheet 4.
Since they are connected in layers via 4, 45, the contact piece 351
~ 353 are arranged side by side as close as possible,
The miniaturization of In addition, the adjacent connection portion 351b
Since the connection positions of ˜353b are distributed in a staggered manner on the front and back surfaces of the flexible substrate 39, even when the contact pieces 351 to 353 are closely connected in parallel, the connection parts 351b to 353b are connected.
A connection space between the 53b and the connection electrodes 391 to 393 can be reliably ensured, and connection work such as soldering can be easily performed.

The flexible substrate 3 coupled to each other is formed.
The contact pieces 351 to 353 to which 9 is connected are
Projections 351a, 352a, 353a of 352, 353
Are fitted into the notches 41 and the square holes 42 and 43 of the support plate 354 from below, respectively, and are fixed to the back surface of the support portion 354b, whereby the brush member 35 is constituted.

As shown in FIG. 8, the brush member 35 is attached to the housing 38 of the camera 1 below the encoder board 34. The brush member 35 is aligned so that the support plate 354 is aligned with the edge portion on the rear surface side of the housing 38,
The fixing portion 354a is fixed and attached to the housing 38 with screws or the like.

As described above, the joined pieces 351 to 35 are joined.
3 is fixed to the lower surface (the surface opposite to the surface facing the encode pattern 341) of the supporting portion 354b of the supporting plate 354,
This supporting portion 354b makes it easy to deform the contact pieces 351 to 351.
Since 53 is protected, the mechanical strength of the brush member 35 is improved and the workability of assembly and the like is improved. Further, the support plate 354 also electrically protects the contact pieces 351 to 353, and thus it is possible to effectively prevent a short circuit or the like of the contact pieces 351 to 353.

FIG. 9 is a circuit block diagram of a signal processing unit for detecting the rotational position (switching position) of the function selection dial.

In the figure, the variable resistor R corresponds to a pattern 341b made of a resistor formed on the intermediate track of the encoder substrate 34, and point a corresponds to the output end of the contact piece 352 pressed against the pattern 341a. ing. Also,
The point b is the innermost ring electrode 34 of the encoder substrate 34.
1a corresponds to the connecting portion 353b of the contact piece 353, and the point c corresponds to the connecting portion 351 of the contact piece 351 pressed against the outermost ring electrode 351c of the encoder substrate 34.
It corresponds to b.

The contact piece 351 is grounded to the ground via the signal line 391 of the flexible board 39, and the contact piece 353 is connected to the power supply voltage V _CC via the signal line 393 of the flexible board 39.
Is applied, a voltage Va obtained by dividing the power supply voltage V _CC by the total resistance value r1 between b and c and the resistance value r2 between a and c is output from the contact piece 352.

When the function selection dial 10 is rotated, the encoder board 34 is rotated integrally with the function selection dial 10, and the contact position of the contact piece 352 on the C-shaped resistor 341b is changed to change the resistance value r2. Since the resistance value r2 increases or decreases in proportion to the rotation angle of the encoder board 34, the contact piece 352
Outputs a predetermined divided voltage Va according to the rotational position of the function selection dial 10.

The divided voltage Va is converted into an 8-bit digital voltage by the A / D converter 46, and then C
It is input to the PU 47. The CPU 47 is a control unit for centrally controlling the photographing operation of the camera 1, and includes a lens driving unit 48 and a shutter driving unit arranged in the camera body B based on various photographing modes, control values and correction values set by the function selection dial 10. Each drive unit such as the unit 49 and the flash drive unit 50 is controlled to take a picture.

Further, the CPU 47 uses the input digital voltage value Va to determine the rotational position of the function selection dial 10, that is, the symbol mark 1 set in the alignment mark 18.
0a is discriminated, a function selection mode is set in accordance with the discrimination result, and the drive of the display drive section 51 is controlled to display the required information on the display section 19.

The above determination is performed using, for example, a conversion table showing the relationship between the digital voltage value Va and the selected function shown in Table 1 below.

[0058]

[Table 1]

For example, the digital voltage value Va input from the A / D converter 46 is $ 20 to $ 3F (0.14 · V _{CC to} 0.28).
If it is within the range of (V _CC ), the rotation position of the function selection dial 10 is determined to be the position of the mark of the light emission arrow, and the flash lamp light emission setting mode is set. If the digital voltage value Va is in the range of $ C0 to $ DF (0.86 · V _{CC to} V _CC ), the rotation position of the function selection dial 10 is “+”.
The position of the mark "/-" is determined, and the mode for setting the exposure correction value is set.

As described above, the divided voltage V _CC of the power supply voltage V _CC
Since the rotation position of the function selection dial 10 is detected by detecting a, it is possible to reliably detect the switching with relatively high accuracy even if the switching positions increase.

Further, the detected voltage may vary for each camera 1 due to an assembly error or a variation in the characteristics of each material. In this case, the divided voltage Va in each function selection mode after the assembly of each camera 1 is performed. Is measured, and the conversion table is set based on the measurement result.

In the above embodiment, the encoder substrate 34 is attached to the lower end of the rotary shaft of the function selection dial 10 so as to be integrally rotatable.
0 is attached to the upper cover case 37, the function selection dial 10 and the encoder board 34 are separated, and when the function selection dial 10 is attached to the rotary shaft 36 protruding from the housing 38, the function selection dial 10
The encode pattern may be formed directly on the lower surface of the.

Although the dial switch of the camera has been described in the present embodiment, the present invention is not limited to the switch of the camera as long as it is a rotary changeover switch, and various electric devices such as video, television and the like. The present invention can be applied to changeover switches of measuring instruments and the like, and is not limited to dial switches. For example, the present invention can also be applied to an operation unit having a shape in which an operation lever is provided so as to project from a disk-shaped main body.

Further, in the present embodiment, the symbol mark (selected contents) displayed on the surface of the function selection dial 10.
Although the switch of the type that aligns with the alignment mark 18 on the main body side has been described, the present invention provides the alignment mark on the rotary changeover switch, and rotates the rotary changeover switch to provide the alignment mark on the main body side. It can also be applied to rotary switches of the type adapted to the selected contents.

[0065]

As described above, according to the present invention,
On the back surface of the rotation operation portion, two endless electrodes are formed concentrically with respect to the rotation axis, and a C-shaped resistor whose both ends are respectively connected to the inner track electrode and the outer track electrode is formed. On the other hand, in the middle part, when the electrodes are arranged in parallel at the same interval as the track intervals of the electrode pattern, three strip-shaped contact pieces provided with projecting coupling parts that overlap with each other are provided, and each coupling part is provided with an insulating sheet. Since the brush member is fixed in a laminated state via the brush member, and the brush member is arranged at a position below the rotation operation unit so that the projections of the contact pieces are brought into pressure contact with the electrode and the resistor, respectively. The structure of the rotary type changeover switch is simple and small, and the pressure contact of the brush member to the conductive pattern is stable, so that the rotational position can be reliably detected.

Since the shape of the conductive pattern is simple,
The accuracy of the contact position of each contact piece with the conductive pattern is increased.
In particular, since the rotational position is detected by the divided voltage, the rotational position of the rotary operation portion can be reliably detected with higher accuracy than the accuracy of the contact position between the brush member and the conductive pattern.

Further, in the brush member in which a plurality of contact pieces are arrayed and connected in parallel to each other at a predetermined interval, each contact piece is provided with a connecting portion which overlaps with each other, and each connecting portion is laminated with an insulating sheet interposed therebetween. Since the respective contact pieces are fixed by being joined with each other, the brush member becomes small in size, and the brush member can be easily assembled.

Further, since the contact piece connected by the connecting portion is fixed to the surface of the support plate opposite to the surface facing the conductive pattern, the weak contact piece is protected by the support plate and can be easily formed. There is no deformation. As a result, contact defects can be reduced. Further, since the supporting plate protects the parts other than the protruding part of the contact piece, electrical defects such as a short circuit can be reduced. Furthermore, handling of the brush member is facilitated, and assemblability is improved.

Further, when connecting the substrates on which the signal lines are formed to the respective connecting portions of the contact pieces joined by the above-mentioned joining portions, the respective connecting portions are arranged so that the adjacent connecting portions are opposite to each other on the substrate. Are connected to the corresponding signal lines, a sufficient connection space is secured for each connection portion, and connection work such as soldering can be performed relatively easily. Further, since the connection space is effectively used, the board connecting portion can be downsized.

[Brief description of the drawings]

FIG. 1 is a front view of a camera provided with a function selection dial having a rotational position detection structure according to the present invention.

FIG. 2 is a rear view of a camera provided with a function selection dial having a rotational position detection structure according to the present invention.

FIG. 3 is a top view of a camera provided with a function selection dial having a rotational position detection structure according to the present invention.

FIG. 4 is a schematic diagram showing an internal configuration of a camera provided with a function selection dial having a rotational position detection structure according to the present invention.

5 is a cross-sectional view of main parts taken along the line AA in FIG.

FIG. 6 is a diagram showing an encode pattern formed on an encoder substrate.

FIG. 7 is an exploded perspective view showing a structure of a brush member.

FIG. 8 is a perspective view of an essential part showing a mounting state of a brush member to a camera housing.

FIG. 9 is a circuit block diagram of a signal processing unit for detecting a rotational position of a function selection dial.

FIG. 10 is a schematic view showing a conventional rotary position detection structure of a dial switch.

[Explanation of symbols]

 1 camera 2 shooting lens unit 3 viewfinder objective window 4 metering window 5 ranging window 6 auxiliary light emitting section 7 flash window 8 red-eye reduction / self-timer display emitting window 9 release button 10 function selection dial (rotation operation section) 11 slide switch 12 LCD display illumination button 13 Diopter adjustment dial 14 Viewfinder eyepiece window 15 Main switch 16 Spot metering button 17 AF reset button 18 Alignment mark 19 Display (LCD) 20 Shooting screen frame 21 Patrone storage room 22 Main condenser 23 Motor 24 Drive unit 25 Battery storage chamber 26 Stopcket 27 Drive shaft 28 Rewinding reel 29 Distance measuring element 30 Funder optical system 31 Photometric element 32 Lamp 33 Flash lamp 34 Encoder board 341 Encoding pattern (conductive pattern) ) 341a, 341c Electrode 341b Resistor 342 Insulating substrate 35 Brush members 351 to 353 Contact piece (conductive contact piece) 351a to 353a Projection portion 351b to 353b Connection portion 351c to 353b Coupling portion 354 Support plate 354a Fixed portion 354b Support portion 354c Side part 36 Rotating shaft 37 Upper case 38 Housing 39 Flexible substrate 390 Connection part 391-393 Connection electrode 40 Round hole 41 Notch (hole) 42,43 Square hole (hole) 44,45 Insulation sheet 46 A / D converter 47 CPU 48 Lens drive unit 49 Shutter drive unit 50 Flash drive unit 51 Display drive unit B Camera body

Claims (3)

[Claims] 1. A brush member slides relatively on a conductive pattern formed on a concentric circle with respect to a rotation axis of the rotary operation part by a rotation operation of the rotary operation part, and a contact position of the brush in the conductive pattern. In the rotational position detection structure of the rotary type changeover switch for detecting the rotational position of the rotary operation part, the conductive pattern is formed on the back surface of the rotary operation part and formed on the outermost and innermost tracks. Electrode and a C-shaped resistor formed on an intermediate track between the two tracks and having both ends respectively connected to the inner track electrode and the outer track electrode. The brush member has a tip end portion and a base end portion. On each of which is formed a protrusion and a connecting portion to which the signal line is externally connected,
When arranged in parallel at the same interval as the track interval of the electrode pattern in the middle part, three strip-shaped contact pieces having mutually overlapping connecting portions protruding in the lateral direction with respect to the longitudinal direction are provided. A rotation characterized by being fixed in a laminated state via an insulating sheet, and the projections of each contact piece being pressed against the electrode and the resistor respectively, and being provided below the rotation operation section. Rotational position detection structure of type changeover switch. 2. The rotary position detecting structure for a rotary changeover switch according to claim 1, wherein the brush member has three holes formed in parallel at the same intervals as the track intervals of the conductive pattern. Of the supporting plate, the contact piece connected by the connecting portion projects to the conductive pattern side from the hole on the surface opposite to the surface facing the conductive pattern of the supporting plate. A rotary position detection structure for a rotary changeover switch, which is supported by being made to rotate. 3. The connecting portion of each contact piece of the brush member is such that the connecting portions of the adjacent contact pieces are on opposite surfaces of the board to the signal line formed on the front and back surfaces of the board to be externally connected. ,
The rotary position detecting structure for the rotary changeover switch according to claim 2, wherein the rotary position detecting structures are connected to each other.