JP2010185940A - Diaphragm plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm plate capable of preventing separation thereof from a lens barrel when air is sprayed to a lens. <P>SOLUTION: First, a convergent lens 13 is fixed in a lens barrel 11 when a projection lens 10 is assembled. Then, a caulking rivet 11b protruding from a gap 11a of a diaphragm plate 14 is inserted into a caulking aperture 14b to perform heat caulking, fixing the diaphragm plate 14 to the lens barrel 11. After fixing the diaphragm plate 14, air is sprayed towards the convergent lens 13 through a diaphragm aperture 14a from a front surface 14e side of the diaphragm plate 14 to remove foreign substances. The air sprayed to the convergent lens 13 is escaped from a notch 14d for air escape to the front surface 14e side of the diaphragm plate 14. Thus, damage of the caulking rivet 11b, which occurs when pressure is concentrated on the heat caulking portion of the diaphragm plate 14, is prevented. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a diaphragm plate fixed in a lens barrel such as a projection lens of a projector.

  The projector causes the image light from the image display unit to enter the projection lens and projects an image on the screen. In the lens barrel of the projection lens, a converging lens on which image light from the image display unit enters, a diaphragm plate having a diaphragm aperture through which image light incident on the converging lens passes, and light that has passed through the diaphragm aperture are imaged The imaging lens to be stored is housed. In recent years, as a device for reducing the manufacturing cost of a projector, each lens is made of plastic, and the diaphragm plate is made of a thin resin (film) having a thickness of about 0.5 mm.

  In assembling the projection lens, first, a converging lens is inserted, and then a diaphragm plate is attached. On the inner surface of the lens barrel of the projection lens, a step is formed that protrudes toward the central axis. The aperture plate presses one surface against the step of the lens barrel, and inserts the caulking hole into a caulking pin extending parallel to the axial direction of the central axis of the lens barrel from the step to heat the lens barrel. Fixed to. Here, when the converging lens is made of plastic, when heat caulking is performed, foreign matters such as dust and dirt easily adhere to the surface of the converging lens due to static electricity. For this reason, after fixing the diaphragm plate to the lens barrel, it is common to remove foreign matter adhering to the surface of the converging lens by blowing air to the converging lens through the aperture opening.

JP 2007-219049 A

  However, when air is blown onto the converging lens, the flow of the blown air changes and air is blown toward the aperture plate. As described above, since the diaphragm plate is formed of a thin resin, the pressure when air is blown onto the diaphragm plate is concentrated on the heat caulking portion, and the caulking pin is damaged by this pressure. was there. If the caulking pin is damaged, the aperture plate is detached from the lens barrel, and the aperture plate must be fixed again by thermal caulking, so that the production efficiency of the projection lens is lowered.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a diaphragm plate that can prevent the lens from being detached from the lens barrel when air is blown onto the lens.

In achieving the above object, the present invention provides an aperture plate that has an aperture opening formed substantially at the center and is attached to the lens barrel so as to face the lens in the lens barrel.
At least one of an air escaping opening for escaping air blown to the lens through the aperture opening and an air escaping notch with its edge cut away is formed around the aperture opening.

  The lens barrel includes a step protruding from the inner surface thereof and a crimping pin extending from the step in parallel to the axial direction of the central axis, and the crimping pin is inserted into a crimping hole formed around the aperture opening. Then, it is preferably fixed to the lens barrel by performing heat caulking.

  In addition, it is preferable that the preliminary caulking pin is formed at the step and the preliminary caulking pin protrudes from the air escape opening or the air escape notch in a state where the preliminary caulking pin is fixed to the step.

  According to the first aspect of the present invention, air blown onto the lens can be released, so that it is possible to prevent the diaphragm plate from being detached from the lens barrel when air is blown onto the lens. In addition, since the weight of a diaphragm plate becomes light, it also becomes possible to reduce the product weight which uses a diaphragm plate.

  According to the second aspect of the present invention, it is possible to prevent pressure from concentrating on the heat caulking portion and damaging the caulking pin and the diaphragm plate. It can prevent coming off from the cylinder.

  According to the third aspect of the invention, even if the caulking pin is damaged by air, it can be reused without replacing the lens barrel, so that it is possible to prevent an increase in manufacturing cost caused by replacing the lens barrel. .

It is a schematic longitudinal cross-sectional view of the lens barrel using this invention. It is explanatory drawing which shows the structure of an aperture plate. It is explanatory drawing which shows the structure of the aperture_diaphragm | restriction board which formed the opening for rectangular air escape. It is explanatory drawing which shows the structure of the aperture_diaphragm | restriction board which formed the opening for circular air escape. It is explanatory drawing which shows the structure of the aperture_diaphragm | restriction board which formed the opening for air escape which has arrange | positioned the rectangular opening in matrix form.

  As shown in FIG. 1, a projection lens 10 for a projector includes a lens barrel 11. The lens barrel 11 is screwed to the front surface of the projector housing 12. A converging lens 13, an aperture plate 14, an imaging lens 15, and a focus lens 16 are held inside the lens barrel 11. Each of these members is arranged side by side along the optical axis P (center axis). The diaphragm plate 14 is formed in a sheet shape having elasticity with a resin having a thickness of 0.5 mm. The converging lens 13, the imaging lens 15, and the focus lens 16 are made of plastic. Each lens is shown as one block, but may be either a single lens or a plurality of lenses.

  Although simply shown, an image display unit 17 is incorporated inside the projector housing 12 so that full-color image light is incident on a projection optical system incorporated in the lens barrel 11. The image display unit 17 combines, for example, three liquid crystal panels illuminated with basic color lights of R, G, and B obtained by dividing white light from a light source with a dichroic mirror, and images from these liquid crystal panels. It consists of a cross dichroic prism.

  Image light (light) from the image display unit 17 is incident on a converging lens (lens) 13 and passes through a diaphragm aperture 14 a formed at a substantially central portion of the diaphragm plate 14. The image light that has passed through the aperture opening 14 a is imaged by the imaging lens 15, and an image is projected onto a screen (not shown) via the focus lens 16. By causing image light to enter the imaging lens 15 through the aperture 14a, flare and ghost of the image projected on the screen are prevented.

  On the inner surface of the lens barrel 11, a step 11a protruding toward the optical axis P is formed over the entire circumference. A cylindrical caulking pin 11b extending in parallel with the axial direction of the optical axis P is protruded from the step 11a. The caulking pin 11b protrudes toward the rear surface 14c which is one surface of the diaphragm plate 14 and faces the converging lens 13. Further, three caulking pins 11b arranged at 120 degree intervals in the circumferential direction of the lens barrel 11 form a set, and two sets of six are formed by changing the positions of the lens barrel 11 in the circumferential direction. Has been. In the periphery of the aperture opening 14a of the aperture plate 14, crimping holes 14b for inserting the crimping pins 11b are formed in three places at intervals of 120 degrees in the circumferential direction. The diaphragm plate 14 inserts one set of caulking pins 11b into the three caulking holes 14b, presses the rear surface 14c that faces one side of the converging lens 13 and heats the caulking pins 11b. The lens barrel 11 is fixed. On the other hand, a set of caulking pins 11b that are not used for fixing the diaphragm plate 14 is reserved. In the figure, the caulking pin 11b that has been caulked by heat shows a state in which the tip thereof is crushed and welded to the diaphragm plate 14, and the caulking pin 11b for reserve shows a columnar state prior to caulking. Note that the number of caulking pins 11b and the number of sets thereof may be appropriately set.

  As shown in FIG. 2, the diaphragm plate 14 is formed with three notches 14 d for releasing air with its edge cut out. The air escape notches 14d are arranged at intervals of 120 degrees in the circumferential direction of the diaphragm plate 14 similarly to the caulking holes 14b, and each is arranged between the caulking holes 14b. The air escape notch 14d is notched to a depth that prevents the entire region from being blocked by the step 11a. For this reason, the rear surface 14c side of the diaphragm plate 14 and the front surface 14e side, which is the other surface, communicate with each other via the air escape notch 14d. In a state where the diaphragm plate 14 is fixed to the lens barrel 11, the spare caulking pin 11b protrudes from the air escape notch 14d to the front surface 14e side of the diaphragm plate and escapes through the air relief notch 14d.

  Next, the effect | action by the said structure is demonstrated.

  When the projection lens 10 is assembled, first, the converging lens 13 is inserted into the lens barrel 11 from the rear surface 14c side (the image display unit 17 side in FIG. 1) and fixed. After the converging lens 13 is fixed, the diaphragm plate 14 is inserted into the lens barrel 11 from the opposite side, and the caulking hole 14b of the diaphragm plate 14 is formed in one of the two sets of caulking pins 11b protruding from the step 11a. It is inserted. Thereafter, heat caulking is performed and the diaphragm plate 14 is fixed to the lens barrel 11. Since the converging lens 13 is formed of plastic, foreign matters such as dust and dirt are likely to adhere to the surface due to static electricity when heat caulking is performed. For this reason, after the diaphragm plate 14 is fixed, air is blown from the front surface 14e side toward the converging lens 13 through the diaphragm opening 14a, and foreign matter adhering to the surface of the converging lens 13 is removed. The air blown to the converging lens 13 changes its flow on the surface of the converging lens 13 and is blown toward the rear surface 14 c of the diaphragm plate 14. The air blown to the rear surface 14c of the aperture plate 14 escapes from the air escape notch 14d to the front surface 14e side. For this reason, it can prevent that a pressure concentrates on the heat caulking part of the aperture plate 14, and the caulking pin 11b is damaged. If a set of caulking pins 11b used for fixing the diaphragm plate 14 is damaged, a spare set of caulking pins 11b can be used for fixing the diaphragm plate 14, so that the lens barrel 11 is not replaced. Can be used.

  As described above, it is possible to prevent the caulking pin 11b from being damaged by releasing the air blown to the converging lens 13 from the air escape notch 14d, and the lens barrel 11 can be used without modification. Therefore, it is possible to suppress an increase in manufacturing cost as compared with the case where this is modified. Further, since the weight of the diaphragm plate 14 can be reduced by forming the air escape notch 14d, the weight of the projection lens 10 can be reduced.

  In the above embodiment, the air escape notch 14d is formed. Alternatively, an air relief opening may be formed, or both the air relief notch and the air relief opening may be formed. Further, the number of air relief notches or air relief openings may be appropriately set.

  Specifically, as shown in FIG. 3, for example, three rectangular air relief openings 20 b extending in the circumferential direction of the diaphragm plate 20 are formed around the diaphragm opening 20 a of the diaphragm plate 20. The air release openings 20b are arranged inside the step 11a of the lens barrel 11, and are arranged at intervals of 120 degrees in the circumferential direction of the aperture plate 20. The air blown to the converging lens 13 can be released also in the air escape opening 20b.

  As shown in FIG. 4, for example, circular air relief openings 30 b are formed in three places around the diaphragm opening 30 a of the diaphragm plate 30. The air escape openings 30 b are arranged inside the step 11 a of the lens barrel 11, and are arranged at intervals of 120 degrees in the circumferential direction of the aperture plate 30. The air blown to the converging lens 13 can be released also in the air escape opening 30b.

  Further, as shown in FIG. 5, for example, a rectangular opening extending in the circumferential direction of the diaphragm plate 40 is arranged in a matrix around the diaphragm opening 40 a of the diaphragm plate 40, and the air relief opening 40 b is formed in a mesh shape. Are formed in three places. The air escape openings 40b are arranged inside the step 11a of the lens barrel 11, and are arranged at intervals of 120 degrees in the circumferential direction of the aperture plate 40. The air blown to the converging lens 13 can be released also in the air escape opening 40b.

  In the above embodiment, the diaphragm plate is fixed to the lens barrel by heat caulking. For example, the lens mirror is fixed by screwing a metal plate in which a cut is made in a part of the peripheral surface and the cut part is bent to one side. The method of fixing the aperture plate to the lens barrel, such as attaching to the tube and inserting the caulking opening of the aperture plate into the bent part of the metal plate, or fixing the aperture plate to the lens barrel by bonding, is appropriate. The method is good.

  In the above embodiment, the present invention is applied to a lens barrel of a projection lens used in a projector. However, the present invention may be applied to a lens barrel other than a projector such as a camera. Furthermore, the lens that blows air is not limited to the converging lens 13, but may be another lens such as an imaging lens or an autofocus lens.

11 Lens barrel 11a Step 11b Caulking pin 13 Converging lens (lens)
14, 20, 30, 40 Diaphragm plate 14a, 20a, 30a, 40a Diaphragm opening 14c Rear surface 14d Air relief notch 14e Front surface 20b, 30b, 40b Air relief opening

Claims (3)

In the diaphragm plate that has a diaphragm opening formed in a substantially central portion and is attached to the lens barrel so as to face the lens in the lens barrel.
At least one of an air escaping opening for escaping air blown to the lens through the aperture opening or an air escaping notch with its edge cut away is formed around the aperture opening. A diaphragm plate to be used. The lens barrel includes a step protruding from an inner surface thereof, and a caulking pin extending from the step in parallel to the axial direction of the central axis,
The aperture plate according to claim 1, wherein the aperture plate is fixed to the lens barrel by inserting the caulking pin into a caulking hole formed around the aperture opening and performing thermal caulking. Forming the preliminary caulking pin on the step,
3. The diaphragm plate according to claim 2, wherein in the state fixed to the step, the spare caulking pin protrudes from the air escape opening or the air escape notch.

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