JP3961655B2 - Light amount adjusting device and image input device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light amount adjustment device provided in an image input device such as a video camera or a digital still camera, and more particularly to a light amount adjustment device having an ND (neutral density) filter for light amount adjustment.
[0002]
[Prior art]
As shown in FIG. 6, the conventional light amount adjusting device is used in a state where a ND filter 67 is attached to the diaphragm blade 63 with an adhesive 68 and a portion 67a used as a filter from the diaphragm blade 63 protrudes a certain amount. . In this case, since the thickness of the diaphragm increases, it is necessary to increase the distance between the lenses 72A and 72B when the light amount adjusting device 71 is attached to the camera shown in FIG. It was.
[0003]
In the light quantity adjusting device 71 shown in FIG. 7, 71A is an ND filter (67), and 71B and 71C are diaphragm blades (63) that move oppositely. The ND filter is bonded to one of the diaphragm blades. Reference numeral 71D denotes a diaphragm blade support plate. Reference numerals 72A, 72B, 72C, and 72D denote component lenses constituting the photographing optical system 72, reference numeral 73 denotes a low-pass filter, and reference numeral 74 denotes a solid-state image sensor.
[0004]
Here, if the plate thickness of the aperture blade and the ND filter is reduced, the distance between the lenses 72A and 72B can be reduced.
[0005]
[Problems to be solved by the invention]
However, when the diaphragm blade and the ND filter are thinned, there is a problem that these warpages increase.
[0006]
Also, it is difficult to manage the amount of adhesive, such as when the amount of adhesive is large, the adhesive protrudes, and when the amount of adhesive is small, the ND filter peels off from the aperture blade.
[0007]
Moreover, since the ND filter is positioned by adhesion to the aperture blade, it is difficult to accurately position the ND filter. In addition, the ND filter may be warped due to curing shrinkage stress during bonding.
[0008]
Therefore, an object of the present invention is to provide a light amount adjusting device that is thin, can adjust the light amount with high accuracy, and can be easily assembled.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention , in the light amount adjusting device having the aperture changing member that changes the size of the aperture opening, the aperture changing member is arranged in the same plane on the base material of the aperture changing member . A light shielding region formed by coating a light shielding material on a base material and a plurality of ND filter regions on which a vapor deposition layer for reducing light transmittance is formed are provided on the base material, and light in the plurality of ND filter regions is provided. The number of vapor deposition layers for decreasing the transmittance is different from each other .
[0010]
That is, unlike the conventional structure in which the ND filter is bonded to the aperture changing member, the region that functions as the aperture blade and the region that functions as the ND filter are integrally formed in the same base material, thereby causing problems such as warpage and positioning. Therefore, a light amount adjusting device that is thinner than the conventional one is realized.
[0011]
In the above invention, it is desirable to form a vapor deposition layer for preventing reflection between the base material and the vapor deposition layer for decreasing the light transmittance. In addition, by forming a plurality of vapor deposition layers for reducing the light transmittance in the ND filter region and forming a vapor deposition layer for preventing reflection therebetween, the light transmittance as an ND filter while preventing reflection. May be set freely.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIG. 1 shows an exploded view of the light amount adjusting device according to the first embodiment of the present invention. This light amount adjusting device is used in place of the light amount adjusting device 71 in the camera (image input device) shown in FIG.
[0017]
In this figure, 1 is a stationary structure of a light quantity adjusting device, and a diaphragm base plate having an optical path opening 1a, 3 and 4 are first diaphragm blades that move relatively in the longitudinal direction of the diaphragm base plate 1, and 2 is for an ND filter. The region 2 a and the light shielding region are integrally formed, and are second diaphragm blades (a diaphragm changing member referred to in the claims) that move in the longitudinal direction of the diaphragm base plate 1.
[0018]
The first aperture blades 3 and 4 are formed with driving elongate holes 3b and 4b. These driving elongate holes are connected to an output shaft 5a of a motor (stepping motor or the like) 5 and are driven to swing. The drive pin 6a of the drive member 6 is fitted.
[0019]
The first diaphragm blades 3 and 4 are formed with openings 3f and 4f for defining an optical path, and are formed with guide long holes 3c, 3d, 4c and 4d. Guide pins 8, 9, 10, 11 formed on the throttle base plate 1 are fitted in the long holes.
[0020]
On the other hand, a driving slot 2b is formed in the second diaphragm blade 2, and a driving member connected to and driven by an output shaft of a motor (not shown) (stepping motor or the like) in the driving slot. Twelve drive pins are fitted.
[0021]
The second aperture blade 2 has guide slots 2c and 2d formed therein, and guide pins 10 and 11 formed on the aperture base plate 1 are fitted in the guide slots.
[0022]
Here, the structure of the 2nd aperture blade 2 is demonstrated in detail using FIG. 2 and FIG. As shown in FIG. 3, the second diaphragm blade 2 is provided with a light-shielding region in which a light-shielding coating 21 is applied on a vapor deposition substrate (base material in the claims) 20 and a reflection on the vapor deposition substrate 20. ND filter regions 2a in which Al ₂ O ₃ vapor deposition layers (first, _third, and fifth layers) and TiOx vapor deposition layers (second, fourth, and sixth layers) for reducing light transmittance are alternately formed are provided.
[0023]
As the substrate 20, PET or PEN having high rigidity, high transparency, and high heat resistance is used. In order to make the second diaphragm blade 2, first, in order to process only the light shielding area, the portion to be the ND filter area is masked with a stainless steel tool, and electroless nickel plating is used to give rigidity. After that, in order to provide light shielding properties, spray coating of a polyamideid resin solution (light shielding material) is performed.
[0024]
Next, the masking is removed from the portion that becomes the ND filter region, and the portion other than the portion that becomes the ND filter region is shadowed with an Al plate having a high heat dissipation property to form the vapor deposition layer.
[0025]
The light transmittance in the ND filter region varies depending on the total thickness of the TiOx vapor deposition layer, and the light transmittance decreases as the thickness increases. For this reason, what is necessary is just to set the number of TiOx vapor deposition layers according to the required light transmittance.
[0026]
Further, since the neutrality of the light transmittance in the wavelength range of 400 nm to 700 nm varies depending on x of the TiOx film composition, the transmittance distribution can be made neutral by appropriately selecting x. Preferably, the numerical value of x is in the range of 0.5 or more and 2 or less, and when x = 1.2, a phenomenon occurs in which the transmittance at a low wavelength is lowered with a wavelength of about 550 nm as a boundary. On the other hand, when x = 1.2 or more, it is inclined to increase the transmittance of the low wavelength. For this reason, it is important to make the transmittance neutral by monitoring the transmittance during vapor deposition.
[0027]
In addition, during the deposition of the Al ₂ O ₃ deposition layer, the reflectance can be reduced by monitoring the reflectance and controlling the film thickness.
[0028]
(Second Embodiment)
FIG. 4 shows a diaphragm blade used in a light amount adjusting device according to the second embodiment of the present invention. The diaphragm blade 42 is used in place of the second diaphragm blade 2 of the light amount adjusting device described in the first embodiment.
[0029]
This diaphragm blade 42 is also formed by integrally forming the ND filter region and the light shielding region in the same manner as the second diaphragm blade of the first embodiment, but the first is that two ND filter regions are formed. Different from the embodiment.
[0030]
That is, the number of TiOx vapor deposition layers for reducing the light transmittance is changed between the first ND filter region 42a and the second ND filter region 42b. When making this diaphragm blade 42, first, after performing TiOx vapor deposition on the entire surface of the first and second ND filter regions 42a and 42b by the number of layers necessary for the first ND filter region 42a having high light transmittance, Only the first ND filter region 42a is shadowed with an Al plate, and TiOx vapor deposition is performed on the second ND filter region 42b where the light transmittance is lowered. Then, light shielding coating is performed on portions other than these ND filter regions 42a and 42b.
[0031]
(Third embodiment)
FIG. 5 shows a diaphragm blade used in a light amount adjusting device according to the third embodiment of the present invention. The diaphragm blade 52 is used in place of the second diaphragm blade 2 of the light amount adjusting device described in the first embodiment.
[0032]
This diaphragm blade 52 is also formed by integrally forming the ND filter region and the light shielding region in the same manner as the second diaphragm blade of the first embodiment, but the first is that four ND filter regions are formed. Different from the embodiment.
[0033]
That is, the number of TiOx vapor deposition layers for decreasing the light transmittance is changed between the first to fourth ND filter regions 52a to 52d. The diaphragm blades 52 are made in the same manner as the diaphragm blades of the second embodiment. First, the number of layers required for the first ND filter region 52a having the highest light transmittance in all the filter regions 52a to 52d. After the TiOx deposition, (1) the first to third ND filter regions 52a to 52c, (2) the first and second ND filter regions 52a and 52b, and (3) the first ND filter region 52a are made of an Al plate. The process of performing TiOx vapor deposition with shadowing is repeated. Then, light shielding coating is performed on portions other than the ND filter regions 52a to 52d.
[0034]
(Fourth embodiment)
In each of the above embodiments, the case where a transparent substrate (colorless or colored not suitable for an ND filter) is used as a substrate for performing light-shielding coating and vapor deposition for reducing light transmittance has been described. A diaphragm blade having a light shielding region and an ND filter region may be integrally formed using a substrate having a light transmittance suitable for an ND filter.
[0035]
In this case, since the substrate itself has a function as an ND filter, it is not necessary to perform vapor deposition in the ND filter region. As with the first embodiment, the light shielding region is masked with a stainless steel tool for the ND filter region, electroless nickel plating is applied to provide rigidity, and then light shielding properties are provided. In order to achieve this, a polyamideimide resin solution is spray-coated.
[0036]
When a plurality of ND filter regions having different light transmittances are formed as in the second and third embodiments, a TiOx vapor deposition layer (if necessary) is formed on the ND filter region other than the region where the substrate is used as it is as an ND filter. For example, an Al ₂ O ₃ vapor deposition layer may be formed.
[0037]
【The invention's effect】
As described above, according to the present invention , the region functioning as the light shielding member and the region functioning as the ND filter are formed on the same base material by painting or vapor deposition, and the aperture changing member with the ND filter is integrally formed. The light quantity adjusting device can be reduced in thickness without reducing the aperture changing member itself. For this reason, the distance between the lenses arranged with the light quantity adjusting device interposed therebetween can be reduced, and the magnification can be improved. In addition, the ND filter portion can be arranged at an accurate position with respect to the aperture.
[0038]
Furthermore, since it is not necessary to bond the ND filter as in the prior art, problems such as sticking out of the adhesive and peeling of the ND filter can be eliminated, and assembly can be easily performed.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a light amount adjusting apparatus according to a first embodiment of the present invention.
FIG. 2 is an enlarged perspective view of a diaphragm blade of the light amount adjusting device.
FIG. 3 is a partial cross-sectional view of the diaphragm blade.
FIG. 4 is an enlarged perspective view of a diaphragm blade in a light amount adjusting device according to a second embodiment of the present invention.
FIG. 5 is an image view of diaphragm blades in a light amount adjusting apparatus according to a third embodiment of the present invention.
FIG. 6 is an enlarged perspective view of a conventional diaphragm blade.
FIG. 7 is a configuration diagram of a camera including a conventional light amount adjusting device.
[Explanation of symbols]
1 Diaphragm base plate 2, 42, 52, 63 (with ND filter) Diaphragm blades 2a, 42a, 42b, 52a to 52d ND filter region 20 Deposition substrate 21 Light-shielding coating 3, 4 Diaphragm blade 5 Motor

Claims (3)

In the light amount adjusting device having an aperture changing member that changes the size of the aperture opening,
The diaphragm changing member is in the same plane on the substrate of the diaphragm changing member, and a light shielding region formed by coating a light-shielding material on the substrate, deposition for lowering the light transmittance on the substrate A plurality of ND filter regions in which a layer is formed ,
The light quantity adjusting device, wherein the number of vapor deposition layers for decreasing the light transmittance in the plurality of ND filter regions is different from each other .   The light quantity adjusting device according to claim 1, wherein a vapor deposition layer for preventing reflection is formed between the base material and a vapor deposition layer for reducing light transmittance. An image input device comprising the light amount adjusting device according to claim 1 .

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