JP2011221358A - Light quantity adjusting device, lens barrel, and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the amount of movement of diaphragm blades to be increased and improve contrast.SOLUTION: The device includes: a diaphragm base 111 in which an aperture part 111a for passing light from a light source is formed; multiple diaphragm blades, such as diaphragm blades 112 and 113, which are provided movably in a direction perpendicular to an optical axis 101 of the light passing through an aperture 111a to form a diaphragm aperture 116 that is smaller than the aperture 111a; a diaphragm blade driving motor 114 for moving the multiple diaphragm blades to increase/decrease an opening amount of the diaphragm aperture 116; and a diaphragm cover 115 for forming a blade chamber 118 that houses the diaphragm blades 112 and 113 between the diaphragm cover 115 and diaphragm base 111. The blade chamber 118 is provided with a ventilation hole 119 for externally exhausting heat inside the blade chamber 118.

Description

  The present invention relates to a light amount adjustment device, a lens barrel, and a projection device that move an aperture blade to increase or decrease the aperture amount of the aperture opening.

  Conventionally, a light source unit configured by a lamp or the like supported by a reflector, an image forming unit for forming an image, and a projection unit (lens barrel) configured by a lens or the like for projecting the image are provided. A liquid crystal projector (projection device) is known. Such a liquid crystal projector can increase the contrast by narrowing the image light with a diaphragm blade (light quantity adjusting device) provided in the projection unit.

FIG. 12 is a sectional view in the direction of the optical axis 401 showing a lens barrel 400 for a conventional liquid crystal projector.
As shown in FIG. 12, the lens barrel 400 includes a light amount adjusting device 410, a lens 420 disposed on the light source side, a lens 430 disposed on the projection side, and the light amount adjusting device 410 and the lenses 420 and 430 on the inner surface. And a lens barrel 440 to be held.

  Here, the light amount adjusting device 410 includes a pair of upper and lower diaphragm blades 412 and 413. The diaphragm blades 412 and 413 are accommodated in a blade chamber 418 formed by the diaphragm base 411 and the diaphragm cover 415. The aperture amount of the aperture 416 can be increased or decreased by moving the aperture blades 412 and 413 with each other by the aperture blade drive motor 414.

  In such a light quantity adjustment device 410, when the diaphragm blades 412 and 413 are squeezed to increase the contrast, the amount of light received by the incident side surfaces 412a and 413a increases, and the diaphragm blades 412 and 413 become high temperature. The heat of the diaphragm blades 412 and 413 having reached a high temperature is dissipated into the blade chamber 418 and is released to the internal space of the lens barrel 440 from the emission side surfaces 412 b and 413 b that are outside the blade chamber 418.

  However, since heat radiation from the exit side surfaces 412b and 413b is not sufficient, the inside of the blade chamber 418 gradually becomes higher in accordance with the amount of light received by the entrance side surfaces 412a and 413a. When the inside of the blade chamber 418 becomes high temperature, heat cannot be radiated from the diaphragm blades 412 and 413 into the blade chamber 418, and the temperature of the diaphragm blades 412 and 413 increases.

  Since the diaphragm blades 412 and 413 are generally made of synthetic resin, when the temperature of the diaphragm blades 412 and 413 exceeds the heat resistance limit of the synthetic resin, the diaphragm blades 412 and 413 are deformed. Therefore, the diaphragm amounts of the diaphragm blades 412 and 413 are limited so that the amount of light received by the incident side surfaces 412a and 413a is within a predetermined range. As a result, there is a certain limit to improving the contrast by focusing the image light.

  Therefore, a technique is known in which a metal heat-resistant plate is attached to the incident side surfaces 412a and 413a of the diaphragm blades 412 and 413 made of synthetic resin. According to this technique, the diaphragm blades 412 and 413 are made of synthetic resin to ensure smoothness of operation, quietness, durability, and the like, and the heat resistance can be improved by the metal heat-resistant plate.

JP 2009-237295 A

  However, since the weight of the diaphragm blade is increased by the metal heat-resistant plate in the technique disclosed in Patent Document 1, a large driving force is required to smoothly operate the diaphragm blade. In addition, since a process for newly attaching a heat-resistant plate is required, the manufacturing process becomes complicated and costs increase.

  Therefore, the problem to be solved by the present invention is to increase the aperture amount of the aperture blade without attaching a heat-resistant plate and to improve the contrast.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 is provided with a stop base formed with an opening for allowing light from a light source to pass therethrough, movably provided in a direction perpendicular to the optical axis of the light passing through the opening, The aperture blade is accommodated between the aperture base for forming an aperture aperture smaller than the aperture, aperture aperture driving means for moving the aperture aperture to increase or decrease the aperture amount of the aperture aperture, and the aperture base And a diaphragm cover that forms a blade chamber, and the blade chamber is a light amount adjusting device having a vent hole for releasing the heat in the blade chamber to the outside.

According to a fourth aspect of the present invention, the same diaphragm base, diaphragm blades, diaphragm blade driving means, and diaphragm cover as those of the invention of the first aspect, a lens disposed in parallel with the diaphragm blades, An aperture blade and a lens barrel that holds the lens on the inner surface, and the blade chamber is a lens barrel having a vent hole for releasing heat in the blade chamber to the internal space of the lens barrel.
Furthermore, the invention described in claim 6 includes the same diaphragm base, diaphragm blades, diaphragm blade driving means, diaphragm cover, lens, and lens barrel as those of the invention described in claim 4, A projection device having a vent hole similar to the invention.

(Function)
The invention according to the first, fourth, and sixth aspects has a vent hole for releasing the heat in the blade chamber accommodating the diaphragm blades to the outside (inner space of the lens barrel). Therefore, the heat of the diaphragm blades escapes from the blade chamber through the ventilation hole to the outside, and the temperature rise of the diaphragm blades is suppressed.

  According to the present invention, since the temperature increase of the diaphragm blades is suppressed by the heat radiation from the vent hole, it is possible to increase the diaphragm amount of the diaphragm blades. As a result, the contrast of the projection device can be improved.

It is a side view which shows the optical unit in the liquid crystal projector as one Embodiment of the projection apparatus of this invention. It is a side view which shows the peripheral part of the image formation part of the optical unit shown in FIG. It is a conceptual diagram which shows the structure of the liquid crystal projector as one Embodiment of the projection apparatus of this invention. 1 is a perspective view showing a half of an optical axis direction of a lens barrel for a liquid crystal projector (first embodiment) as an embodiment of a lens barrel of the present invention. FIG. It is a disassembled perspective view which shows the structure of the light quantity adjustment apparatus of the lens barrel shown in FIG. FIG. 6 is a front view showing a state in which the diaphragm blades are opened in the light amount adjusting device shown in FIG. 5. FIG. 6 is a front view showing a state in which the aperture blades are stopped in the light amount adjustment device shown in FIG. 5. It is sectional drawing of the optical axis direction which shows the lens barrel for liquid crystal projectors (1st Embodiment) as one Embodiment of the lens barrel of this invention. It is sectional drawing of the optical axis direction which shows the lens-barrel (2nd Embodiment) for liquid crystal projectors as one Embodiment of the lens-barrel of this invention. It is a perspective view which shows the half of the optical axis direction of the lens barrel (3rd Embodiment) for liquid crystal projectors as one Embodiment of the lens barrel of this invention. It is sectional drawing of the optical axis direction which shows the lens barrel (3rd Embodiment) for liquid crystal projectors as one Embodiment of the lens barrel of this invention. It is sectional drawing of the optical axis direction which shows the lens barrel for conventional liquid crystal projectors.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
Here, it is assumed that the projector according to the present invention is the liquid crystal projector 10 in the following embodiment. Further, the lens barrel in the present invention is assumed to be the lens barrel 100, 200, 300 for the liquid crystal projector 10 in the following embodiment. Furthermore, the light amount adjusting device according to the present invention is assumed to be the light amount adjusting devices 110, 210, and 310 provided in the lens barrels 100, 200, and 300 in the following embodiments.
The description will be given in the following order:

1. First embodiment (lens barrel: configuration example of vent hole)
2. Second embodiment (lens barrel: configuration example provided with forced cooling means)
3. Third embodiment (lens barrel: configuration example in which a barrel is provided with a distribution port)

[Example of configuration of projection apparatus]

FIG. 1 is a side view showing an optical unit 20 in a liquid crystal projector 10 as an embodiment of the projection apparatus of the present invention.
FIG. 2 is a side view showing the periphery of the image forming unit 40 of the optical unit 20 shown in FIG.
FIG. 3 is a conceptual diagram showing the configuration of the liquid crystal projector 10 as an embodiment of the projection apparatus of the present invention.
As shown in FIGS. 1 to 3, the optical unit 20 in the liquid crystal projector 10 according to the present embodiment includes a light source unit 30, an image forming unit 40, and a projection unit 50.

Here, the light source unit 30 includes a lamp 31, a reflector 32, and a protective glass 33.
The lamp 31 is a metal halide lamp, a xenon lamp, a halogen lamp, or the like that emits unpolarized white light including red light (R light), green light (G light), and blue light (B light), and is conventionally known. Various lamps can be used. The white light emitted from the lamp 31 is reflected by the reflector 32 to become parallel light and is emitted from the protective glass 33.

The image forming unit 40 includes fly-eye lenses 34a and 34b, a PS conversion element 35, and a condenser lens 36.
The fly-eye lenses 34 a and 34 b are arranged in a pair at positions spaced from the protective glass 33, and make the luminance distribution of light emitted from the protective glass 33 uniform. The PS conversion element 35 includes a polarization beam splitter arranged in a strip shape and a phase difference plate provided intermittently corresponding to the polarization beam splitter, and converts the polarization direction. Therefore, the light emitted from the condenser lens 36 enters the image forming unit 40 as parallel light aligned with predetermined polarized light (for example, p-polarized light).

Furthermore, the image forming unit 40 includes a cross dichroic mirror 41, reflection mirrors 42 a and 42 b, and a dichroic mirror 43.
The white light emitted from the condenser lens 36 is transmitted by the cross dichroic mirror 41 to light in the blue wavelength region on the short wavelength side (B light) and light in the red and green wavelength regions on the long wavelength side (R light + G light). ) And are separated. The B light is reflected by the reflection mirror 42a, and the R light + G light is reflected by the reflection mirror 42b. Further, the short wavelength G light in the R light + G light is reflected by the dichroic mirror 43, and the long wavelength R light is transmitted through the dichroic mirror 43. Therefore, the G light and the R light are separated by the dichroic mirror 43.

  Further, the image forming unit 40 includes polarizing elements 44R, 44G, and 44B, reflective liquid crystal panels 45R, 45G, and 45B, a spacer plate 46, and a cross dichroic prism 47. The polarizing elements 44R, 44G, 44B and the reflective liquid crystal panels 45R, 45G, 45B are fixed to the side surfaces of the spacer plate 46, and the spacer plates 46 are fixed to the upper and lower surfaces of the cross dichroic prism 47.

  The polarizing element 44R transmits the p-polarized R light that has passed through the dichroic mirror 43 and enters the liquid crystal panel 45R. The liquid crystal panel 45R that displays red image information applies a video signal corresponding to the R light, and rotates and modulates the polarization direction of the R light. The R light spatially modulated by the liquid crystal panel 45R and converted into s-polarized light is reflected by the polarizing element 44R and enters the cross dichroic prism 47.

  Similarly, the polarizing element 44G transmits the G light which is p-polarized light reflected by the dichroic mirror 43 and makes it incident on the liquid crystal panel 45G. The liquid crystal panel 45G displaying the green image information applies a video signal corresponding to the G light, rotates the polarization direction of the G light, and outputs the modulated signal. The G light spatially modulated by the liquid crystal panel 45G and converted into s-polarized light is reflected by the polarizing element 44G and enters the cross dichroic prism 47.

  Similarly, the polarization element 44B transmits the B light, which is p-polarized light separated by the cross dichroic mirror 41 and reflected by the reflection mirror 42a, and enters the liquid crystal panel 45B. The liquid crystal panel 45B displaying the blue image information applies a video signal corresponding to the B light, and rotates and modulates the polarization direction of the B light. The B light spatially modulated by the liquid crystal panel 45B and converted to s-polarized light is reflected by the polarizing element 44B and enters the cross dichroic prism 47.

The cross dichroic prism 47 combines the incident R light, G light, and B light as one image light, and guides it to the projection unit 50. The image light guided to the projection unit 50 is enlarged and projected onto the screen via the lens barrel 100.
Such a liquid crystal projector 10 can be applied not only for business use with a relatively small enlargement rate but also for halls and theaters with a large enlargement rate.

<1. First Embodiment>
[Configuration example of lens barrel]

FIG. 4 is a perspective view showing a half in the direction of the optical axis 101 of the lens barrel 100 (first embodiment) for the liquid crystal projector 10 (see FIG. 3) as an embodiment of the lens barrel of the present invention. It is.
As shown in FIG. 4, the lens barrel 100 includes a light amount adjusting device 110, a lens 120 disposed on the light source side, a lens 130 disposed on the projection side, and a lens barrel 140.

Here, the light amount adjusting device 110 of the first embodiment includes a diaphragm base 111, a pair of upper and lower diaphragm blades 112 and 113 (made of synthetic resin in the first embodiment), and a diaphragm blade drive motor 114 ( Equivalent to the diaphragm blade driving means of the present invention) and a diaphragm cover 115. A blade chamber 118 that accommodates the diaphragm blades 112 and 113 is formed between the diaphragm base 111 and the diaphragm cover 115, and a ventilation hole 119 is provided in the blade chamber 118. The light amount adjusting device 110 and the lenses 120 and 130 are held on the inner surface of the lens barrel 140, and the diaphragm blades 112 and 113 and the lenses 120 and 130 are arranged in parallel.
In the first embodiment, two diaphragm blades 112 and 113 are used, but the number of diaphragm blades may be one or three or more.

  Here, the aperture base 111 is formed with an opening 111a for allowing the image light from the cross dichroic prism 47 (see FIG. 3) to pass therethrough. The diaphragm blades 112 and 113 are provided so as to be able to reciprocate up and down in a direction perpendicular to the optical axis 101 of the light passing through the opening 111a, and are moved in opposite directions by the diaphragm blade driving motor 114. Therefore, the aperture amount of the aperture opening 116 between the aperture blade 112 and the aperture blade 113 can be increased or decreased. In the state shown in FIG. 4, an aperture aperture 116 smaller than the aperture 111a is formed.

FIG. 5 is an exploded perspective view showing the configuration of the light amount adjusting device 110 of the lens barrel 100 shown in FIG.
As shown in FIG. 5, the light amount adjusting device 110 includes diaphragm blades 112 and 113, a diaphragm blade drive motor 114, a diaphragm cover 115, and a diaphragm blade drive arm 117.
The light amount adjusting device 110 also includes an aperture base 111 (see FIG. 4), but is not shown in FIG.

  Here, the diaphragm cover 115 is arranged in a direction perpendicular to the optical axis 101, and a circular opening 115a corresponding to the opening 111a of the diaphragm base 111 shown in FIG. 4 is formed. Therefore, the image light from the cross dichroic prism 47 (see FIG. 3) reaches the diaphragm blades 112 and 113 after passing through the opening 115a. Further, four guide pins 115b are integrally formed on the aperture cover 115. Furthermore, convex rails 115c are provided in two rows.

  The diaphragm blade 112 has a guide hole 112a for inserting the guide pin 115b, and the diaphragm blade 113 has a similar guide hole 113a. Therefore, the aperture blades 112 and 113 are independently attached to the aperture cover 115 by inserting the guide pins 115b into the guide holes 112a and 113a. Further, the aperture blades 112 and 113 can reciprocate in a direction perpendicular to the optical axis 101 while reducing frictional force on the rail 115c by the guide holes 112a and 113a formed in the long holes.

  Furthermore, the aperture blade drive motor 114 is fixed to the aperture cover 115 by screw fastening or adhesion. A diaphragm blade drive arm 117 is attached to the rotary shaft of the diaphragm blade drive motor 114, and drive pins 117a and 117b are integrally formed at both ends of the diaphragm blade drive arm 117. The drive pin 117a fits into the cam hole 112b of the diaphragm blade 112, and the drive pin 117b fits into the cam hole 113b of the diaphragm blade 113.

  The cam holes 112b and 113b convert the forward / reverse rotation of the diaphragm blade drive arm 117 into the reciprocating movement of the diaphragm blades 112 and 113. Therefore, if the diaphragm blade driving arm 117 is rotated forward and backward by the diaphragm blade driving motor 114, the driving force of the diaphragm blade driving motor 114 is transmitted to the cam holes 112b and 113b, and the diaphragm blades 112 and 113 reciprocate in the opposite directions. To move. The diaphragm blades 112 and 113 enter and exit the opening 115a while being guided by the guide pins 115b.

FIG. 6 is a front view showing a state in which the aperture blades 112 and 113 are opened in the light amount adjusting device 110 shown in FIG.
FIG. 7 is a front view showing a state in which the diaphragm blades 112 and 113 are stopped in the light amount adjusting device 110 shown in FIG.

  When the lamp 31 (see FIG. 3) is not lit, the diaphragm blades 112 and 113 are completely accommodated in the blade chamber 118 (see FIG. 4), and the opening 115a is fully opened as shown in FIG. Specifically, the diaphragm blade drive arm 117 is rotated counterclockwise by the diaphragm blade drive motor 114, and the diaphragm blade 112 is moved above the diaphragm cover 115 and the diaphragm blade 113 is moved below the diaphragm cover 115. . Therefore, the aperture blades 112 and 113 are opened, and the opening 115a is fully opened.

Next, in order to bring the diaphragm blades 112 and 113 into the narrowed state as shown in FIG. 7, the diaphragm blade drive arm 117 is rotated clockwise by the diaphragm blade drive motor 114. As a result, the aperture blade 112 moves below the aperture cover 115 and the aperture blade 113 moves above the aperture cover 115. As a result, a diaphragm aperture 116 smaller than the aperture 115a (see FIG. 6) of the diaphragm cover 115 is formed, and the image light is narrowed by the diaphragm aperture 116, so that the contrast can be improved.
It should be noted that such an aperture 116 can be automatically formed during projection. In the first embodiment, the two diaphragm blades 112 and 113 realize the two-stage diaphragm. However, the diaphragm can be adjusted steplessly by the three diaphragm blades.

FIG. 8 is a cross-sectional view in the optical axis 101 direction showing a lens barrel 100 (first embodiment) for a liquid crystal projector 10 (see FIG. 3) as an embodiment of the lens barrel of the present invention. .
The state shown in FIG. 8 is a state in which the diaphragm blades 112 and 113 are narrowed, and the diaphragm blades 112 and 113 form a diaphragm opening 116 that is smaller than the opening 115 a (see FIG. 6) of the diaphragm cover 115. Therefore, the diaphragm blades 112 and 113 receive image light at the incident side surfaces 112a and 113a.

As described above, when the incident side surfaces 112a and 113a are exposed to strong image light for a long time, the diaphragm blades 112 and 113 are heated by the image light. The heat of the diaphragm blades 112 and 113 that has reached a high temperature is dissipated into the blade chamber 118 that accommodates the diaphragm blades 112 and 113, and also from the exit side surfaces 112 b and 113 b that are outside the blade chamber 118. Escaped to the internal space.
However, since heat radiation from the emission side surfaces 112b and 113b is not sufficient, the temperature in the blade chamber 118 rises according to the amount of light received by the incidence side surfaces 112a and 113a.

  Here, vent holes 119 (119a, 119b) are provided in a direction perpendicular to the optical axis 101 between the diaphragm base 111 and the diaphragm cover 115 forming the blade chamber 118 (118a, 118b). . Therefore, relatively low-temperature air existing in the inner space of the lens barrel 140 enters the lower blade chamber 118b from the vent hole 119b and takes the heat of the diaphragm blade 113. Further, the air in the blade chamber 118 b is discharged into the inner space of the lens barrel 140 from the aperture base 111 and the gap between the aperture cover 115 and the aperture blade 113.

Similarly, relatively cold air existing in the inner space of the lens barrel 140 enters the upper blade chamber 118a from the gap between the diaphragm base 111 and the diaphragm cover 115 and the diaphragm blade 112, and the heat of the diaphragm blade 112 is dissipated. Take away. Further, the air in the blade chamber 118a is discharged from the vent hole 119a to the internal space of the lens barrel 140.
In the first embodiment, the vent holes 119 (119a, 119b) are provided in a direction perpendicular to the optical axis 101, but may be provided in a direction parallel to the optical axis 101. In that case, for example, the vent hole is provided on a plane parallel to the diaphragm blades 112 and 113 of the diaphragm base 111.

Thus, the lens barrel 100 of the first embodiment can release the heat in the blade chambers 118a and 118b to the outside from the vent holes 119a and 119b. Therefore, by restricting the diaphragm blades 112 and 113 made of synthetic resin, the diaphragm blades 112 and 113 are efficiently cooled even if the amount of light received by the incident side surfaces 112a and 113a is increased. Never exceed. As a result, the diaphragm amount can be increased as compared with the conventional one while ensuring smooth responsiveness and quietness by the synthetic resin diaphragm blades 112 and 113, and thus the contrast can be improved.
Although the diaphragm blades 112 and 113 are made of synthetic resin, the diaphragm blades 112 and 113 are excellent in terms of silence and the like, but the diaphragm blades may be made of metal.

<2. Second Embodiment>
[Configuration example of lens barrel]

FIG. 9 is a cross-sectional view in the optical axis 201 direction showing a lens barrel 200 (second embodiment) for the liquid crystal projector 10 (see FIG. 3) as an embodiment of the lens barrel of the present invention. .
The lens barrel 200 of the second embodiment shown in FIG. 9 is similar to the lens barrel 100 of the first embodiment shown in FIG. 8, and the light amount adjusting device 210 and the lens 220 arranged on the light source side. A lens 230 disposed on the projection side, and a lens barrel 240.

  The light amount adjusting device 210 includes a diaphragm base 211, a pair of upper and lower diaphragm blades 212 and 213, a diaphragm blade drive motor 214 (corresponding to the diaphragm blade drive means of the present invention), and a diaphragm cover 215. The diaphragm base 211 and the diaphragm cover 215 form a blade chamber 218, and the blade chamber 218 is provided with a vent hole 219 in a direction perpendicular to the optical axis 201.

Furthermore, in the lens barrel 200 of the second embodiment, a forced cooling fan 250 (corresponding to the forced cooling means of the present invention) is attached to the light amount adjusting device 210. The forced cooling fan 250 can forcibly release the heat in the blade chamber 218 to the outside. Therefore, even if the diaphragm blades 212 and 213 are throttled and the amount of light received by the incident side surfaces 212a and 213a increases, the heat of the diaphragm blades 212 and 213 is forcibly released from the blade chamber 218 to the internal space of the lens barrel 240. Is done. As a result, the diaphragm blades 212 and 213 can be cooled more efficiently.
In the second embodiment, the forced cooling fan 250 is installed inside the lens barrel 240 to avoid an increase in the size of the lens barrel 200, but may be installed outside the lens barrel 240.

<3. Third Embodiment>
[Configuration example of lens barrel]

FIG. 10 is a perspective view showing a half in the direction of the optical axis 301 of a lens barrel 300 (third embodiment) for a liquid crystal projector 10 (see FIG. 3) as an embodiment of the lens barrel of the present invention. It is.
FIG. 11 is a cross-sectional view in the direction of the optical axis 301 showing a lens barrel 300 (third embodiment) for the liquid crystal projector 10 as an embodiment of the lens barrel of the present invention.

  The lens barrel 300 according to the third embodiment shown in FIGS. 10 and 11 is arranged on the light source side with the light amount adjusting device 310 similarly to the lens barrel 100 according to the first embodiment shown in FIG. A lens 320, a lens 330 disposed on the projection side, and a lens barrel 340. The light amount adjusting device 310 and the lenses 320 and 330 are held on the inner surface of the lens barrel 340, respectively.

  The light amount adjusting device 310 includes an aperture base 311, a pair of upper and lower aperture blades 312 and 313, an aperture blade drive motor 314 (corresponding to the aperture blade drive means of the present invention), and an aperture cover 315. The diaphragm base 311 and the diaphragm cover 315 form a blade chamber 318, and the blade chamber 318 is provided with a vent hole 319 in a direction perpendicular to the optical axis 301.

  Here, in the lens barrel 300 of the third embodiment, the circulation ports 341 and 342 are formed in the barrel 340 at a position facing the vent hole 319. Therefore, low-temperature outside air flows from the circulation ports 341 and 342 into the blade chamber 318 and takes heat of the throttle blades 312 and 313. Furthermore, the air that has reached a high temperature in the blade chamber 318 is discharged into the atmosphere from the circulation ports 341 and 342. As a result, the diaphragm blades 312 and 313 can be cooled more efficiently.

Further, since the circulation ports 341 and 342 use the zoom guide holes originally provided in the lens barrel 340, it is not necessary to provide new holes. In other words, the light amount adjusting device 310 is attached at a position where the zoom guide hole and the ventilation hole 319 face each other so that the zoom guide hole functions as the circulation ports 341 and 342. Therefore, the cooling capacity can be improved without increasing the manufacturing cost of the lens barrel 300.
A forced cooling fan (forced cooling means) that opens a hole in the lens barrel 340 and forcibly releases the heat in the blade chamber 318 to the outside may be installed under the lens barrel 340. If a forced cooling fan is inserted into the lens barrel 340, the image may be shaken. However, the occurrence of such a problem can be avoided by using the lens barrel 340 outside.

As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, The following various deformation | transformation are possible. For example,
(1) In the embodiment, the vent hole 119 is provided in a direction perpendicular to the optical axis 101. However, the present invention is not limited to this, and any position, shape, or the like that allows heat in the blade chamber 118 to escape to the outside. .

(2) Although the two diaphragm blades 112 and 113 are provided in the embodiment, the number of diaphragm blades may be one or three or more.
In the embodiment, the aperture amount is increased or decreased by the aperture blades 112 and 113 in two stages, that is, the fully opened state of the aperture 115a and the formed state of the aperture aperture 116. However, the present invention is not limited to this, and the opening amount may be increased or decreased continuously according to the intensity of the image light.

10 Liquid crystal projector (projection device)
DESCRIPTION OF SYMBOLS 100 Lens barrel 110 Light quantity adjusting device 111 Aperture base 111a Opening 112,113 Aperture blade 114 Aperture blade drive motor (aperture blade drive means)
115 Diaphragm cover 116 Diaphragm opening 118 Blade chamber 119 Vent hole 200 Lens barrel 210 Light quantity adjusting device 211 Aperture base 212, 213 Diaphragm blade 214 Diaphragm blade drive motor (diaphragm blade drive means)
215 Aperture cover 218 Vane chamber 219 Vent hole 250 Forced cooling fan (forced cooling means)
DESCRIPTION OF SYMBOLS 300 Lens barrel 310 Light quantity adjusting device 311 Aperture base 312,313 313 Diaphragm blade 314 Diaphragm blade drive motor (diaphragm blade drive means)
315 Aperture cover 318 Blade chamber 319 Vent hole 341,342 Flow outlet

Claims (6)

A diaphragm base having an opening for allowing light from the light source to pass through;
A diaphragm blade provided to be movable in a direction perpendicular to the optical axis of the light passing through the opening, and forming a diaphragm aperture smaller than the opening;
A diaphragm blade driving means for moving the diaphragm blade to increase or decrease the opening amount of the diaphragm opening;
A diaphragm cover that forms a blade chamber that houses the diaphragm blades between the diaphragm base and
The vane chamber has a vent hole for releasing heat in the vane chamber to the outside. The light amount adjusting device according to claim 1,
The air vent is provided in a direction perpendicular or parallel to an optical axis of light passing through the opening. The light amount adjusting device according to claim 1,
A light quantity adjusting device comprising forced cooling means for forcibly releasing the heat in the blade chamber to the outside and cooling the diaphragm blade. A diaphragm base having an opening for allowing light from the light source to pass through;
A diaphragm blade provided to be movable in a direction perpendicular to the optical axis of the light passing through the opening, and forming a diaphragm aperture smaller than the opening;
A diaphragm blade driving means for moving the diaphragm blade to increase or decrease the opening amount of the diaphragm opening;
A diaphragm cover that forms a blade chamber that houses the diaphragm blades between the diaphragm base,
A lens disposed parallel to the diaphragm blades;
A lens barrel that holds the aperture blade and the lens on the inner surface;
The blade chamber has a vent hole for releasing heat in the blade chamber to an internal space of the lens barrel. The lens barrel according to claim 4,
The vent hole is provided in a direction perpendicular to the optical axis of light passing through the opening,
The lens barrel has a flow port through which air inside and outside the lens barrel is circulated at least at a position facing the vent hole. A diaphragm base having an opening for allowing light from the light source to pass through;
A diaphragm blade provided to be movable in a direction perpendicular to the optical axis of the light passing through the opening, and forming a diaphragm aperture smaller than the opening;
A diaphragm blade driving means for moving the diaphragm blade to increase or decrease the opening amount of the diaphragm opening;
A diaphragm cover that forms a blade chamber that houses the diaphragm blades between the diaphragm base,
A lens disposed parallel to the diaphragm blades;
A lens barrel that holds the aperture blade and the lens on the inner surface;
The blade chamber has a vent hole for releasing the heat in the blade chamber to the internal space of the lens barrel.

Images