JP2006018105A - Light quantity controller and camera equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light quantity controller contributing to the improvement of yield and the reduction of a product cost, and to provide a camera equipped with the light controller. <P>SOLUTION: The pressure plate 34 of a shutter apparatus 21 is provided with an optical aperture 39, and movably holds a light shielding curtain 35 between a substrate 37 and the plate 34. A spacer 36 is prepared for keeping a distance between the substrate 37 and the pressure plate 34. Electric polarization (electret) is previously applied on the light shielding curtain 35 at desired pitches. The substrate 37 is provided with four belt-like electrodes 38 as many as the number of phases (4 phases) of a driving signal as the absolute minimum number to drive the light shielding curtain 35 on the side of a retreat part 23 adjacent to the optical aperture part 22. The light shielding curtain 35 is constituted so as to always face the four belt-like electrodes 38 arranged on the substrate 37 until the curtain 35 is moved from the retreat part 23 so as to close the optical aperture part 22 after the curtain 35 is retreated from the optical aperture part 22 to the retreat part 23. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light amount adjusting device that contributes to yield improvement and product cost reduction.

2. Description of the Related Art Conventionally, camera shutters and diaphragm devices have been proposed in which a dielectric charge actuator is applied to a light amount adjusting device such as a camera shutter mechanism. As the mechanism, there are one and two sliders (movers) for one stator (stator), and both of them function as shutter blades or diaphragm blades. (For example, refer to Patent Document 1.)
Japanese Patent Laid-Open No. 08-220592 ([Summary], FIG. 1, [0011], FIG. 2)

  By the way, the substrate (stator) of the light amount adjusting device disclosed in Patent Document 1 is provided with a strip-like electrode over the entire moving range of the light shielding curtain (moving element). And the width | variety of the strip | belt-shaped electrode provided in the board | substrate is several tens micrometer, the arrangement | positioning pitch is as fine as about 100 micrometers, and when this is arrange | positioned over the range of at least 10 mm or more, it will exceed 100 strip | belt-shaped electrodes. Must be formed on the substrate.

  However, if even one of the strip electrodes provided on the substrate is defective, the light shielding curtain cannot be driven, and the substrate itself must be discarded as a defective substrate. As such, even if only one of the strip electrodes is defective, the substrate must be discarded. This reduces the yield of substrate production, and if the yield decreases, the substrate is very expensive. A problem arises that the unit price of

  In view of the above-described conventional situation, an object of the present invention is to provide a light amount adjusting device that contributes to yield improvement and cost reduction of a product, and a camera including the same.

The configuration of the light amount adjusting device according to the present invention and the camera including the same will be described below.
First, the light amount adjusting device of the first invention includes at least a light shielding curtain previously polarized at a desired interval, a strip electrode for driving the light shielding curtain, and a substrate having an optical opening. In the light amount adjusting device, the belt-like electrode is configured to be provided in a range narrower than a moving range of the light shielding curtain in a moving direction of the light shielding curtain.

  The strip electrode is provided in the same number as the number of phases of the driving signal for driving the light shielding curtain, and is configured so that the same number as the phase number always faces the light shielding curtain in the movement range of the light shielding curtain. The

  In this light amount adjusting device, the strip electrode may be configured to be further provided in a range where the light shielding curtain is retracted from the optical opening, for example, and the light shielding curtain overlaps with the optical opening, for example. You may comprise so that it may further be provided in a range.

In addition, it is preferable that the light quantity adjusting device further includes, for example, a pressing plate that holds the light-shielding curtain movably between the substrate and the substrate.
Next, a camera according to a second aspect of the invention comprises any one of the light amount adjusting devices described above provided at the shutter position or aperture position of the optical system.

  According to the present invention, since the strip electrode is provided in a range narrower than the moving range of the light shielding curtain in the moving direction of the light shielding curtain, it is possible to reduce the possibility of the occurrence of a defect of the belt shaped electrode per substrate. Therefore, it is possible to provide a light amount adjusting device that can contribute to the improvement of the yield and the reduction of the product cost, and a camera equipped therewith.

Embodiments of the present invention will be described below with reference to the drawings.
1A and 1B are diagrams showing a schematic configuration of a digital camera as a camera provided with a light amount adjusting device of the present invention. FIG. 1A is a perspective view showing an external appearance of the digital camera, and FIG. 1B is a digital camera. It is a perspective view which shows the arrangement | positioning state of an internal principal part.

  As shown in FIG. 1A, the digital camera 1 includes a photographic lens window 2 in the upper right corner of the front surface and a strobe irradiation window 3 on the left side thereof. A release button 4 is provided at the left end of the upper surface.

  As shown in FIG. 1B, the interior of the digital camera 1 occupies about 2/3 of the entire left side, and a control device including a circuit board 5 on which various electronic components are mounted, a detachable / replaceable battery 6 and the like are arranged. Has been. A unitized lens device 7 is disposed in a portion occupying approximately 1/3 of the entire right side.

  The lens device 7 reflects the light beam from the subject incident along the photographing optical axis O1 shown in FIG. 1B from the photographing lens window 2 in FIG. 1A so that the optical axis O1 bends substantially perpendicularly downward. Along the second optical axis O2 (described later) bent downward, the incident light flux is guided to an imaging element such as a CCD disposed at the lower end of the lens device 7 to generate a captured image. .

  Note that the XYZ arrows shown in FIG. 1B indicate the width, depth, and height directions of the camera. The thinner the camera in the Y direction, the thinner the entire camera. This is a configuration suitable for miniaturization and thinning.

  2 is a cross-sectional view taken along the line AA ′ of the lens device 7 shown in FIG. 1B as viewed from the left side of FIG. Inside the lens device 7 shown in FIG. 1B, as shown in FIG. 2, a lens group is held in the first fixed lens frame portion 8 along the second optical axis O2 bent downward. In addition, the first fixed lens section 9, the first moving lens unit 12 in which the lens group is held in the first moving lens frame 11, and the second lens group in which the lens group is held in the second moving lens frame 13 The moving lens unit 14, the third moving lens unit 16 with the lens held by the third moving lens frame 15, the second fixed lens unit 18 with the lens held by the second fixed lens frame unit 17, and these lenses And an image pickup device 19 disposed at the end of the unit.

  The first moving lens unit 12 and the second moving lens unit 14 change the focal length of the luminous flux of the subject incident along the second optical axis O2 of the optical system of the lens device 7, that is, the zoom ratio. The third moving lens unit 16 is provided for adjustment, and is provided for focus adjustment in which the light beam forms an image on the image sensor 19. A shutter position (also an aperture position) 20 is provided between the first moving lens unit 12 and the second moving lens unit 14.

  3 shows an enlarged perspective view of the lens device 7 shown in FIG. 1B as viewed from the back side of FIG. 1B of the digital camera 1 on the left, and shows the shutter device (or the diaphragm device) alone on the right. Yes. As shown in FIG. 3, the lens device 7 incorporates a shutter device (or an aperture device, hereinafter the same) 21 at the shutter position (aperture position) 20 shown in FIG. As shown on the right side of FIG. 3, the shutter device 21 is a device that forms a rectangular flat plate-like body, and includes an optical opening 22 that serves as a transmission path of the second optical axis O <b> 2, and the optical opening. 22 has a retreating portion 23 adjacent to 22.

2 is disposed at the end of the second optical axis O2 that passes through the optical opening 22 of the shutter device 21, that is, at the lower end of the lens device 7.
Here, the driving principle of the shutter mechanism for driving the light-shielding curtain in the shutter device 21 in this example will be described. For ease of explanation, an example in which a plurality of strip-shaped electrodes are disposed on the entire surface excluding the optical opening and the peripheral edge of the substrate will be described.

  4A and 4B are diagrams illustrating the driving principle of the shutter mechanism in the shutter device of the present invention. In the following description of the driving principle, it will be referred to as a stator instead of a substrate, and a mover instead of a light-shielding curtain.

  The shutter mechanism basically includes a stator 24 and a mover 25 inside, and the mover 25 is configured to be movable in the left-right direction with respect to the stator 24 as shown in FIGS. 4A and 4B. Yes. The stator 24 is provided with an opening (optical opening 26) for guiding a light image from the subject to the image pickup device (see the image pickup device 19 in FIGS. 2 and 3). The strip-shaped electrodes 27 are formed side by side at a predetermined interval. The other mover 25 is a light-shielding member and has a permanently polarized dielectric part. Such a configuration of the mover 25 is called an electret.

  In general, electrets are made by heating and melting polymer materials such as Teflon (registered trademark), polypropylene, and mylar that are difficult to conduct electricity, and solidifying between the electrodes while applying a high DC voltage to the electrodes. When it is removed, it is a term that refers to a surface that is in contact with the electrode being positively or negatively charged, and that these polarizations (a state divided into positive and negative electricity) are maintained semipermanently.

  In the above shutter mechanism, when positive and negative voltages are periodically applied to the belt-like electrode 27, an attractive force or a repulsive force is generated between the belt-like electrode 27 and the electret of the slider 25. As a result, the slider 25 is It moves relative to the stator 24.

  Therefore, the shutter mechanism can be configured by allowing the moving element 25 to move so as to open or shield the opening (optical opening 26) of the stator 24. 4A shows a state where the shutter is open, and FIG. 4B shows a state where the shutter is closed. Hereinafter, the shutter mechanism according to this configuration will be referred to as an “electret shutter”.

  The opening (optical opening 26) of the stator 24 does not necessarily have to be a physical opening such as a through hole. The stator 24 is a transmission member, and a band-like shape is formed at a position corresponding to the opening. A transmission region where the electrode 27 is not provided may be formed.

  FIG. 5 is a diagram schematically showing the electret shutter and its drive circuit. In the figure, a cross section of the electret shutter is schematically shown on the right, and a drive circuit is shown in a block diagram on the left. As shown in the figure, a voltage signal line from a drive (voltage application) circuit 28 is connected to each strip electrode 27 arranged on the stator 24. A four-phase voltage signal is applied to the voltage signal line. Therefore, the same voltage signal is applied to the strip electrode 27 every four lines. In FIG. 5, the voltage signals are distinguished by attaching the symbols A, B, C, and D to the strip electrode 27.

  A moving element 25 is disposed so as to face the surface of the stator 24 on which the strip electrode 27 is disposed. The mover 25 includes a plurality of the above-described dielectrics (electrets) 29 that are permanently polarized on the surface facing the stator 24.

  In the drive circuit 28 shown on the left side of the figure, the pulse generation circuit 31 generates a rectangular wave train (drive pulse signal), and this drive pulse signal is supplied to the booster circuit 32 and the phase shifter 33. The booster circuit 32 boosts the input drive pulse signal to about 100 V, branches it into voltage signals having two polarities, and supplies them to the strip electrodes A and C.

  On the other hand, the drive pulse signal input to the phase shifter 33 has a waveform delayed by 90 °, and is then input to the booster circuit 32 and branched into voltage signals having the same two polarities as described above, and the strip electrode B And D.

  FIG. 6 is a diagram showing a voltage signal sequence generated by the drive circuit 28 and applied to the strip electrode 27. As for the voltage state of the strip electrode 27, four state changes from t1 to t4 in the period T are repeated corresponding to the progress of each period T in the time t.

  7A to 7D are diagrams for further explaining the operation of the electret shutter. 7A shows the correspondence relationship between the electret and the strip electrode immediately after the voltage state of each strip electrode 27 (A, B, C, D) in FIG. 6 is switched to the state of the applied voltage t1 shown in FIG. Show.

  The electret 29 a receives a repulsive force from the strip electrode A and receives a suction force from the strip electrode B. The electret 29 b receives a repulsive force from the strip electrode C and receives a suction force from the strip electrode D. Therefore, the mover 25 receives a force in the right direction in the figure and moves by one band electrode pitch d.

  FIG. 7B shows the correspondence between the electret and the strip electrode immediately after switching to the state of the applied voltage t2 shown in FIG. 6 following the above. The electret 29 a receives a repulsive force from the strip electrode B and receives a suction force from the strip electrode C. The electret 29 b receives a repulsive force from the strip electrode D and receives a suction force from the strip electrode A. For this reason, the moving element 25 receives a force in the right direction in the figure and moves again by one band-shaped electrode pitch d.

  FIG. 7C shows the correspondence relationship between the electret and the strip electrode immediately after switching to the state of the applied voltage t3 shown in FIG. 6 following the above, and FIG. 7D shows FIG. 6 after FIG. 7C. The correspondence relationship between the electret and the strip electrode immediately after switching to the state of the applied voltage at t4 is shown. Similar to the operation described in FIG. 7A and FIG. 7B, the mover 25 sequentially moves by one band-like electrode pitch d.

  Then, by repeating this operation, the mover 25 moves to the right in the figure. In order to move the mover 25 in the left direction in the figure, the polarity of the voltage applied to the strip electrode 27 may be switched in reverse.

  As described above, the movable element 25 of this example itself has a semi-permanent polarization charging unit. Therefore, as in an inductive charge type actuator, for example, the number of steps and time for repeating voltage application, charge storage, and electrostatic induction are repeated. Therefore, the moving element can be driven quickly by simply applying the driving voltage.

  FIG. 8A is an exploded perspective view of the first embodiment of the shutter device 21 shown in FIG. 3, and FIGS. 8B and 8C are diagrams showing the operating state of the shutter device 21. The shutter device 21 shown in FIG. 8A includes a pressing plate 34, a light shielding curtain 35, a spacer 36, and a substrate 37 shown from the lower left to the upper right of the drawing.

  The pressing plate 34 has an optical opening 39 and is provided to hold the light shielding curtain 35 movably between the substrate 37. The spacer 36 is provided to maintain the distance between the substrate 37 and the pressing plate 34. Although the light-shielding curtain 35 does not appear clearly in the drawing, electrical polarization (electret) is applied in advance at a desired pitch. On the substrate 37, four strip electrodes 38 are formed on the side of the retracting portion 23 (see FIG. 3) in the vicinity of the optical opening 22. The belt-like electrode 38 is connected to the drive circuit 28 shown in FIG. 5, and the drive circuit 28 drives and controls the light-shielding curtain 35 as described with reference to FIG.

  In this example, as shown in the drive circuit 28 of FIG. 5, a four-phase voltage signal is applied to the strip electrode 38 to drive the light-shielding curtain 35. In this example, the number of strip electrodes 38 is the minimum number required to drive the light-shielding curtain 35, that is, the number of phases of the drive signal (four).

  The optical openings 22 and 39 do not necessarily need to be physical openings such as through-holes, and may be sufficient if the substrate 37 and the pressing plate 34 are made of transparent members.

  8B shows a state in which the light-shielding curtain 35 is retracted from the optical opening 22 (and 39, hereinafter the same) to the retracting part 23 in the shutter device 21 having the above-described configuration, and FIG. It shows a state in which the optical opening 22 is closed by moving from the above. As can be seen from FIG. 8B and FIG. 8C, the light shielding curtain 35 is moved from the state where it is retracted from the optical opening 22 to the retracting portion 23 to the state where it moves from the retracting portion 23 and closes the optical opening 22. It always faces the four strip electrodes 38 provided on 37.

  Therefore, by supplying a four-phase voltage signal from the driving circuit 28 to the four strip electrodes 38, the light shielding curtain 35 is optically moved from the retracting portion 23 from the position where the light shielding curtain 35 is retracted from the optical opening portion 22 to the retracting portion 23. It can be driven until the opening 22 is closed. Of course, the light shielding curtain 35 can be driven in the opposite direction.

  FIG. 9A is an exploded perspective view of the second embodiment of the shutter device 21 shown in FIG. 3, and FIGS. 9B and 9C are diagrams showing the operating state of the shutter device 21 as the second embodiment. is there. In FIGS. 9A, 9B, and 9C, the same components as those in FIGS. 8A, 8B, and 8C are denoted by the same reference numerals as those in FIGS. 8A, 8B, and 8C.

  The shutter device 21 as the second embodiment shown in FIG. 9A is the same as that of the first embodiment in that the shutter device 21 includes a pressing plate 34, a light shielding curtain 35, a spacer 36, and a substrate 37 shown from the lower left to the upper right of the drawing. Same as the case. However, in this example, the substrate 37 is further retracted from the four strip electrodes 38 ′ in addition to the four strip electrodes 38 ′ provided on the retracting portion 23 side in the vicinity of the optical opening 22. A belt-like electrode 38 is also provided on the side of the portion 23, that is, in a range where the light shielding curtain 35 is retracted from the optical opening 22.

  9B and 9C, only the strip-shaped electrodes 38 'corresponding to the number of phases of the drive signal (four in the body example) provided adjacent to the optical opening 22 are provided on the light-shielding curtain 35. The size of the light shielding curtain 35 is set so as to always face the light shielding curtain 35 in the moving range.

  In this manner, in addition to the four strip electrodes 38 ′, the strip electrode 38 is disposed on the side of the retracting portion 23 from the four strip electrodes 38 ′, so that the light shielding curtain 35 is optically separated from the retracting portion 23. When moving in the direction of closing the opening 22, a larger driving force can be obtained.

  FIG. 10A is an exploded perspective view of a third embodiment of the shutter device 21 shown in FIG. 3 (a diaphragm device in this example), and FIGS. 10B and 10C illustrate a diaphragm as the third embodiment. FIG. 6 is a diagram showing an operation state of the device 21. In FIGS. 10A, 10B, and 10C, the same components as those in FIGS. 8A, 8B, and 8C are denoted by the same reference numerals as those in FIGS. 8A, 8B, and 8C.

  A diaphragm device 21 as a third embodiment shown in FIG. 10A includes a holding plate 34, a light shielding curtain 42 having a diaphragm hole 41, a spacer 36, and a substrate 37, which are shown from the lower left to the upper right of the drawing. In this example, a light shielding curtain 42 is further provided on the substrate 37 in addition to the four strip electrodes 38 ′ provided at the position 43 on the retracting portion 23 side in the vicinity of the optical opening 22. A belt-like electrode 38 is also provided at a position 44 that overlaps with the electrode.

  Also in this example, as shown in FIGS. 10B and 10C, only the strip-shaped electrode 38 ′ corresponding to the number of phases of the drive signal (four in the body example) provided adjacent to the optical opening 22 is shielded. The size of the light-shielding curtain 35 is set so as to always face the light-shielding curtain 35 in the movement range of the curtain 35.

  In this manner, in addition to the four strip electrodes 38 ′, the strip electrode 38 is also disposed at the position 44 where the light shielding curtain 42 overlaps the optical opening 22 from the four strip electrodes 38 ′. When the light shielding curtain 35 moves from the optical aperture 22 toward the retracting portion 23 from the stop position where the light shielding curtain 35 overlaps the optical aperture 22, a larger driving force can be obtained.

  In the first to third embodiments described above, the number of the strip-shaped electrodes always facing the light shielding curtain in the movement range of the light shielding curtain is the number of phases (4) of the drive signal. If so, the number is not limited.

  As described above, according to the present invention, at least the same number of phases as the number of phases of the drive signal for driving the light shielding curtain is provided at the position where the strip electrode provided on the substrate is always opposed to the light shielding curtain in at least the movement range of the light shielding curtain. Thus, the number of strip electrodes can be reduced while maintaining the driving force to the light-shielding curtain, thereby reducing the incidence of defective strip electrodes and improving the yield and the product. It is possible to provide a light amount adjusting device that contributes to cost reduction and a camera including the same.

It is an external appearance perspective view from the front which shows schematic structure of the digital camera as a camera provided with the light quantity adjustment apparatus of this invention. FIG. 1B is a perspective view showing an arrangement state of main parts inside the camera to show a schematic configuration of the digital camera of FIG. 1A. It is a figure which shows schematic structure of each part of the lens unit which looked at the AA 'arrow cross section of the lens apparatus shown to FIG. 1B from the left of FIG. 1B of a digital camera. An enlarged perspective view of the lens device shown in FIG. 1B as viewed from the back side of FIG. 1B of the digital camera is shown on the left side, and a shutter device (or an aperture device) is shown on the right side. It is FIG. (1) explaining the drive principle of the shutter mechanism of the shutter apparatus of this invention. It is FIG. (2) explaining the drive principle of the shutter mechanism of the shutter apparatus of this invention. It is a figure which shows typically the electret shutter and its drive circuit concerning the shutter apparatus of this invention. It is a figure which shows the voltage signal row | line | column produced | generated by the drive circuit of an electret shutter and applied to a strip | belt-shaped electrode. It is FIG. (1) which further demonstrates operation | movement of an electret shutter. FIG. 6 is a second diagram for further explaining the operation of the electret shutter. It is FIG. (3) which further demonstrates operation | movement of an electret shutter. It is FIG. (4) which further demonstrates operation | movement of an electret shutter. It is a disassembled perspective view of 1st Example of the shutter apparatus shown in FIG. FIG. 6 is a diagram (part 1) illustrating an operation state of the shutter device according to the first embodiment. FIG. 6 is a second diagram illustrating an operation state of the shutter device according to the first embodiment. It is a disassembled perspective view of 2nd Example of the shutter apparatus shown to FIG. 3B. It is FIG. (1) which shows the operation state of the shutter apparatus as a 2nd Example. It is FIG. (2) which shows the operation state of the shutter apparatus as a 2nd Example. It is a disassembled perspective view of 3rd Example of the shutter apparatus (diaphragm | squeeze apparatus) shown to FIG. 3B. It is FIG. (The 1) which shows the operation state of the aperture_diaphragm | restriction apparatus as a 3rd Example. It is FIG. (2) which shows the operation state of the aperture_diaphragm | restriction apparatus as a 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Shooting lens window 3 Strobe irradiation window 4 Release button 5 Circuit board 7 Lens apparatus O1 Optical axis O2 2nd optical axis 8 1st fixed lens frame part 9 1st fixed lens part 11 1st Moving lens frame 12 First moving lens unit 13 Second moving lens frame 14 Second moving lens unit 15 Third moving lens frame 16 Third moving lens unit 17 Second fixed lens frame unit 18 Second Fixed lens unit 19 Image sensor 20 Shutter position (aperture position)
21 Shutter device (aperture device)
DESCRIPTION OF SYMBOLS 22 Optical opening part 23 Retraction | saving part 24 Stator 25 Mover 26 Optical opening part 27 Band-shaped electrode 28 Drive circuit 29 Dielectric (electret)
Reference Signs List 31 Pulse Generator 32 Booster 33 Phaser 34 Presser Plate 35 Light-shielding Screen 36 Spacer 37 Substrate 38, 38 'Strip Electrode 39 Optical Opening 41 Diaphragm Hole 42 Light-shielding Screen 43 Position on Retracting Part 44 Light-shielding Screen Optical Opening Position that overlaps the part

Claims (6)

A light quantity adjusting device comprising at least a light shielding curtain previously polarized at a desired interval, a strip electrode for driving the light shielding curtain, and a substrate having an optical opening,
The light amount adjusting device according to claim 1, wherein the strip electrode is provided in a range narrower than a moving range of the light shielding curtain in a moving direction of the light shielding curtain.   The strip electrode is provided with the same number as the number of phases of the drive signal for driving the light shielding curtain, and the same number as the phase number is always opposed to the light shielding curtain in the movement range of the light shielding curtain. The light quantity adjusting device according to claim 1.   3. The light quantity adjusting device according to claim 2, wherein the strip electrode is further provided in a range where the light shielding curtain is retracted from the optical opening.   3. The light quantity adjusting device according to claim 2, wherein the belt-like electrode is further provided in a range where the light shielding curtain overlaps with the optical opening.   2. The light quantity adjusting device according to claim 1, further comprising a pressing plate that movably holds the light shielding curtain between the substrate and the substrate. A camera comprising the light amount adjusting device according to claim 1 at a shutter position or an aperture position of an optical system.

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