JP2011022498A - Projection lens device and projector device - Google Patents

Abstract

Displacement of a focus position of an anomalous dispersion lens caused by a temperature change is corrected with high accuracy.
A projection lens device 10 includes a projection lens system 13 including first to third lens groups 16 to 18, a lens barrel 14 including first to third lens barrel portions 19 to 21, and a connecting member 15. With. The third lens group 18 includes an anomalous dispersion lens 22 and is held by the third lens barrel portion 21. The connecting member 15 is made of an invar material having a low coefficient of thermal expansion, extends from the end surface 12a of the mount portion 12 of the housing 11 along the optical axis L1, and is screwed to the rear end of the third lens barrel portion 21, thereby an anomalous dispersion lens. The axial dimension A is set so that the shift amount of the focus position caused by the temperature change of 22 is offset by the movement amount of the anomalous dispersion lens 22 caused by the temperature change of the third lens barrel portion 21.
[Selection] Figure 1

Description

  The present invention relates to a projection lens device and a projector device using the same.

  In recent years, a projector apparatus that enlarges and projects an image displayed on a light valve such as a liquid crystal panel is often used for presentations. In this projector device, the pixel pitch of the light valve is becoming finer as the resolution of an image supplied from a personal computer or the like is increased. Due to the progress of high-definition light valves, pixel shift due to chromatic aberration in projection lens devices for projector devices, which has not been a problem until now, has become prominent. To prevent this pixel shift, chromatic aberration in projection lens devices There is a need for improved performance.

  In a projection lens apparatus for a projector apparatus, it is effective to use a positive lens having anomalous dispersion as a technique for improving chromatic aberration. However, a lens having anomalous dispersion has a sign of a temperature coefficient of refractive index opposite to that of a lens using a normal glass material, and thus it is difficult to correct a shift amount of a focus position caused by a temperature rise. Therefore, in the lens device described in Patent Document 1, a negative lens having an anomalous dispersion is cemented for the purpose of canceling out a fluctuation in focus position of a positive lens having an anomalous dispersion.

  On the other hand, as another method for correcting the shift of the focus position, the amount of movement of the focus position is offset by the amount of expansion / contraction caused by the temperature change of the correction member interposed between the lens barrel and the lens holding member. The structure which does is known (for example, patent document 2, 3).

JP 2008-46259 A JP-A-2005-308779 JP 2006-48013 A

  The projection zoom lens described in Patent Document 1 includes a negative lens using an anomalous dispersion glass material for correcting the focus position, but a positive lens using an anomalous dispersion glass material is used to improve chromatic aberration. A lens is sufficient, and using an anomalous dispersion glass material as a negative lens as in Patent Document 1 causes an increase in cost.

  In Patent Document 2, a lens barrel for holding a lens and a structure for correcting a focus position caused by thermal expansion of a holding frame are considered. However, no consideration is given to the correction of the focus position deviation caused by the temperature change of the lens group including the anomalous dispersion lens.

  Further, in Patent Document 3, in addition to each lens of the lens group including the anomalous dispersion lens, a light valve for displaying an image is also held in the lens barrel, so that the lens barrel and the lens holding frame can be expanded and contracted. The relative position of the lens group with respect to the light valve also fluctuates, and the back focus of the lens group, that is, the distance from the light source side end surface of the lens group to the light exit surface of the light valve may expand and contract, and the focus may not be achieved.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a projection lens device capable of correcting a shift of a focus position of an anomalous dispersion lens due to a temperature change with high accuracy and a projector device using the same.

  In the projection lens device of the present invention, a projection lens system that enlarges and projects an image formed on a light valve onto a screen by light projected from the light source, and the light source located closest to the light source in the projection lens system A projection lens system including an anomalous dispersion lens having positive refractive power in the side lens group, and holding the projection lens system, and passing through a mount portion provided in a housing of the projector device, at least the light source side lens group A lens barrel that is inserted to a position where a part of the lenses is disposed inside the housing, and the mount portion and the lens barrel are connected, and the light source side of the light source side lens group is connected from the mount portion. While restricting the dimension to the end face, the amount of deviation of the focus position caused by the temperature change of the anomalous dispersion lens is changed to the anomalous dispersion level caused by the temperature change of the lens barrel. Characterized in that a connecting member made of Invar material axial dimension is set from the mounting portion so as to cancel in the amount of movement of the figure.

  The axial dimension of the connecting member is an expansion / contraction that expands / contracts due to a temperature change of the connecting member from an expansion / contraction amount in which the shift amount of the focus position due to the temperature change of the anomalous dispersion lens expands / contracts due to the temperature change of the lens barrel. It is preferably set to be equal to a value obtained by subtracting the amount.

  The lens barrel includes first and second cylindrical body members having different linear expansion coefficients, and the first and second cylindrical body members are stacked concentrically with the optical axis of the light source side lens group. The second cylindrical member has a larger linear expansion coefficient than the first cylindrical member, and the axial dimension of the second cylindrical member is the first cylindrical member. The second cylindrical body member is set to expand and contract to regulate the position of the light source side end surface so as to cancel out the amount of displacement of the light source side end surface due to expansion and contraction of the member. The axial dimension is such that the shift amount of the focus position caused by the temperature change of the anomalous dispersion lens is the expansion / contraction amount by which the second cylindrical body member expands / contracts to the screen side due to the temperature change, and the first cylindrical body. From the difference between the amount of expansion and contraction of the member to the light source due to temperature change, the temperature of the connecting member is further increased. It is preferably set to be equal to the value deformation amount minus the stretch by reduction.

  A projector device according to the present invention includes a light source, a light valve, a housing in which these are housed and provided with a mount, and the projection lens device.

  According to the present invention, the connecting member that connects the mount unit and the lens barrel regulates the dimension from the mount unit to the light source side end surface of the light source side lens group, and focuses due to the temperature change of the anomalous dispersion lens. Since the axial dimension from the mount is set so as to offset the amount of positional deviation with the amount of movement of the anomalous dispersion lens caused by the temperature change of the lens barrel, the focus of the anomalous dispersion lens caused by the temperature change is set. The positional deviation can be corrected with high accuracy, and the cost can be reduced.

It is principal part sectional drawing which shows the structure of a projection lens apparatus. It is a block diagram which shows an example of a projector apparatus. It is principal part sectional drawing which shows the structure of the projection lens apparatus of 2nd Embodiment.

  FIG. 1 is a cross-sectional view of an essential part showing a state in which a projection lens apparatus to which the first embodiment of the present invention is applied is attached to a projector apparatus main body. The projection lens device 10 is attached to a mount portion 12 provided on the front surface of the housing 11 of the projector device body. The mount portion 12 is fixed to the housing 11 by, for example, screwing, and an opening into which the projection lens device 10 is inserted is formed. A screen (not shown) is disposed in front of the projection lens device 10.

  The projection lens device 10 includes a projection lens system 13, a lens barrel 14, and a connecting member 15. Further, inside the housing 11, a dichroic prism 47 and a light valve 46 are disposed behind the projection lens device 10, and a light source (not shown) is disposed behind the light valve 46. Here, L1 in the figure represents the optical axis. As the light valve 46, for example, a liquid crystal panel is used.

  The projection lens system 13 includes a first lens group 16 having a negative refractive power, a second lens group 17 having a positive refractive power, and a third lens group 18 (each having a positive refractive power) in order from the front to the rear, that is, from the screen side to the light source side. The image formed on the light valve 46 is enlarged and projected on the screen by the light projected from the light source.

  The lens barrel 14 includes first to third lens barrel portions 19 to 21 that respectively hold the first to third lens groups 16 to 18. A front end portion of the third lens barrel portion 21 is coupled to the second lens barrel portion 20. The lens barrel 14 is inserted to a position where the second lens barrel portion 20 penetrates the mount portion 12 and the third lens barrel portion 21 and thus the third lens group 18 are accommodated inside the housing 11.

  The first lens barrel portion 19 is attached to the second and third lens barrel portions 20 and 21 so as to be movable in the optical axis direction. The second lens barrel portion 20 includes a fixed barrel 20a coupled to the third barrel portion 21 and a movable barrel 20b attached to the fixed barrel 20a so as to be movable in the optical axis direction. 20 b holds the second lens group 17. In the present embodiment, the projection lens device 10 has a zooming adjustment function for changing the zoom magnification by moving the first lens barrel 19 and thus the first lens group 16 in the optical axis direction. In addition, the projection lens device 10 can perform focus adjustment by moving the movable barrel 20b, and thus the second lens group 17, in the optical axis direction. Note that these zoom adjustment and focus adjustment functions use well-known mechanisms and will not be described.

  The projection lens device 10 of the present embodiment has an anomalous dispersion lens 22 having a positive refractive index in the third lens group 18 positioned closest to the light source in the projection lens system 13 in order to improve chromatic aberration performance. Is included. The anomalous dispersion lens 22 is made of a glass material having an anomalous dispersibility having an Abbe number of 70 or more. The lenses of the third lens group 18 excluding the anomalous dispersion lens 22 and the lenses of the first and second lens groups 16 and 17 are made of a glass material having normal dispersibility. The anomalous dispersion lens 22 is located on the screen side in the third lens group 18, but the position of the anomalous dispersion lens 22 is not limited to this, and any position in the third lens group 18 may be used. Good.

  The connecting member 15 is slightly larger than the third lens barrel portion 21 and extends from the rear end surface of the mount portion 12, that is, the light source side end surface 12a, to the rear end of the third lens barrel portion 21 along the optical axis L1 of the third lens group 18. The tube portion 15a extends and the rear end regulating portion 15b is bent from the tube portion 15a so as to be orthogonal to the optical axis L1 and wraps around the rear end surface of the third lens barrel portion 21. The connecting member 15 is a state in which the rear end regulating portion 15b is screwed to the rear end of the third lens barrel portion 21 by the screw 23, and the front end of the cylindrical portion 15a is in contact with the end surface 12a of the mount portion 12 by the screw 24. It is screwed with. Thereby, since the 3rd lens-barrel part 21 is fixed to the housing | casing 11 via the connection member 15, the position of a rear end is controlled.

The connecting member 15 is made of an invar material having a small coefficient of thermal expansion. As the invar material, for example, an alloy made of 36% nickel and 64% iron is used, and its linear expansion coefficient is 0.14 × 10 ⁻⁵ (/ ° C.). The third lens barrel 21 is made of inexpensive metal or plastic. In this embodiment, the 3rd lens-barrel part 21 consists of one member made from aluminum. The third lens barrel portion 21 made of aluminum has a linear expansion coefficient of 2.3 × 10 ⁻⁵ .

  By fixing the third lens barrel portion 21 to the mount portion 12 of the housing 11 via the connecting member 15, the rear end of the third lens barrel portion 21 from the end surface 12 a of the mount portion 12, and consequently the third lens group 18. The dimension (FB-BF) up to the end face 18a closest to the light source is regulated. Furthermore, when the flange back dimension FB from the mount portion 12 to the light exit surface 46a of the light valve 46 is accurately positioned and fixed, from the end surface 18a of the third lens group 18 to the light exit surface 46a of the light valve 46. The back focus dimension BF is not substantially changed, and is in a regulated state.

  The connecting member 15 is configured so that the shift amount of the focus position caused by the temperature change of the anomalous dispersion lens 22 is offset by the movement amount of the anomalous dispersion lens 22 caused by the temperature change of the third lens barrel portion 21. The dimension in the axial direction from the end face 12a is set.

In the anomalous dispersion lens 22 used in the present embodiment, the focus position of the anomalous dispersion lens 22 with respect to the light exit surface 46a of the light valve 46 moves backward by 70 μm with a temperature rise of 20 ° C. Therefore, the dimension of the connecting member 15 is determined so that the anomalous dispersion lens 22 moves forward by 70 μm with a temperature increase of 20 °. In the present embodiment, as described above, the dimension (FB-BF) from the end surface 12a of the mount portion 12 to the end surface 18a of the third lens group 18 is regulated by the connecting member 15, and the third lens barrel portion 21 is Since it is made of a single member made of aluminum, the amount of movement of the anomalous dispersion lens 22 is equal to the value obtained by subtracting the amount of expansion / contraction of the connecting member 15 from the amount of expansion / contraction of the third lens barrel 21. Therefore, Expression (1) for obtaining the dimension of the connecting member 15 is expressed as follows. A indicates the axial dimension of the connecting member 15.
((2.3 × 10 ⁻⁵ ) − (0.14 × 10 ⁻⁵ )) × 20 × A = 0.070 (1)
From the above equation (1), the axial dimension of the connecting member 15 is A = 162 mm.

  Next, an embodiment of a projector apparatus according to the present invention will be described. The projector device 25 shown in FIG. 2 includes a light source unit 26, an information light generation unit 27 that generates information light from light incident from the light source unit 26, and the projection lens device 10.

  The light source unit 26 includes a lamp 31, a reflecting mirror 32, a UV cut filter 33, an integrator 34, a relay lens 37, a collimating lens 38, a polarizer 39, and the like.

  The lamp 31 is a high-intensity light source such as a xenon lamp, and emits natural white light having no specific polarization direction. The white light emitted from the lamp 31 is removed from the ultraviolet light by the UV cut filter 33 and guided to the integrator 34. The reflecting mirror 32 is, for example, an elliptically curved mirror, and efficiently guides white light emitted from the lamp 31 to the integrator 34.

  The integrator 34 is composed of, for example, a glass rod and a microlens array provided on the end surface of the glass rod, and collects white light emitted from the lamp 31 and guides it to the collimating lens 38 via the relay lens 37. . Further, the integrator 34 adjusts the light having a non-uniform light amount distribution incident from the lamp 31 so that the light amount distribution is substantially uniform within a necessary range around the light source optical axis L2. As a result, the projected image becomes an image with substantially uniform brightness over the entire surface of the screen 40. The collimator lens 38 adjusts the light incident from the integrator 34 into light parallel to the light source optical axis L <b> 2 and makes the light enter the polarizer 39. The polarizer 39 adjusts the light incident from the collimator lens 38 to linearly polarized light, and guides it to the dichroic mirror 42 of the information light generator 27 via the reflecting mirror 41 and the like.

  The information light generator 27 includes dichroic mirrors 42 and 43, transmissive liquid crystal panels 46R, 46G, and 46B as light valves, a dichroic prism 47, and the like.

  The dichroic mirror 42 is provided such that an angle formed between the normal direction of the surface thereof and the optical axis of incident light is 45 degrees. The dichroic mirror 42 transmits the red light component from the linearly polarized white light incident from the light source unit 26 and guides it to the reflecting mirror 49. The reflecting mirror 49 causes the red light incident from the dichroic mirror 42 to enter the liquid crystal panel 46R.

  On the other hand, the dichroic mirror 42 reflects the green light component and the blue light component in the white light incident from the light source unit 26, and guides it to the dichroic mirror 43. The dichroic mirror 43 is arranged such that an angle formed between the normal direction of the surface and the optical axis of incident light is 45 degrees. Further, the dichroic mirror 43 reflects the green light component of the light incident from the dichroic mirror 42 and causes it to enter the liquid crystal panel 46G.

  Further, the dichroic mirror 43 transmits the blue light component of the light incident from the dichroic mirror 42 and guides it to the reflecting mirror 44. The blue light is reflected by the reflecting mirror 44 and the reflecting mirror 45 and enters the liquid crystal panel 46B.

  The liquid crystal panel 46R displays, in gray scale, a component to be displayed in red among projected video data such as an image received from a computer or the like. Therefore, the red light incident from the reflecting mirror 49 becomes red information light having information on the red component of the projected image when transmitted through the liquid crystal panel 46R.

  Similarly, the liquid crystal panel 46G displays the component to be displayed in green in the projection video data in gray scale. Therefore, the light incident from the dichroic mirror 43 becomes green information light having the information of the green component of the projected image when passing through the liquid crystal panel 46G, and enters the cross dichroic prism 47.

  Similarly, the liquid crystal panel 46B displays the component to be displayed in blue in the projected video data in gray scale. Therefore, when the light incident from the reflecting mirror 45 passes through the liquid crystal panel 46B, it becomes blue information light having the information of the blue component of the projected image and enters the cross dichroic prism 47.

  The dichroic prism 47 is formed in a substantially cubic shape using a transparent material such as glass, and includes a dichroic surface 47a and a dichroic surface 47b that intersect with each other. The dichroic surface 47a reflects red light and transmits green light. On the other hand, the dichroic surface 47b reflects blue light and transmits green light. Therefore, the dichroic prism 47 combines the red, green, and blue information lights incident from the liquid crystal panels 46R, 46G, and 46B, respectively, to generate projection light, and guides the projection light to the projection lens device 10 to thereby apply the projection light to the screen 40. Display the projected image in full color.

  The projector device shown in FIG. 2 shows an embodiment of the present invention, and various modifications can be made. For example, in place of the transmissive liquid crystal, other light valves such as LCOS (reflection liquid crystal) or DMD can be used, and the color sequential operation is performed using a single plate light valve. It is also possible.

  The operation of the above configuration will be described. When the projector device 25 is used, a computer or the like is connected to supply projection image data to the liquid crystal panels 46R, 46G, and 46B, and the light source unit 26 is turned on to emit illumination light. As a result, the respective color lights separated by the dichroic mirrors 42 and 43 are transmitted through the liquid crystal panels 46R, 46G and 46B, and a full color image synthesized by the dichroic prism 47 is projected onto the screen 40 by the projection lens device 10.

  While the projector device 25 is continuously used, the temperature of the projection lens device 10 rises due to heat generated by the light source unit 26 and the like, the thickness of the anomalous dispersion lens 22 expands, and the refractive index changes. At this time, the dimension (FB-BF) from the end surface 12 a of the mount portion 12 to the end surface 18 a of the third lens group 18 is regulated by the connecting member 15, and the focus position shift due to the temperature change of the anomalous dispersion lens 22. Since the axial dimension A of the connecting member 15 is set so that the amount is offset by the amount of movement of the anomalous dispersion lens 22 caused by the temperature change of the third lens barrel 21, the anomalous dispersion caused by the temperature change The shift of the focus position of the lens 22 can be corrected. In addition, since only one anomalous dispersion lens 22 is used for the projection lens device 10, the cost of the projection lens device 10 can be reduced.

  In the first embodiment, the third lens barrel portion is formed from one member, and the third lens barrel portion holds the third lens group (light source side lens group) including the anomalous dispersion lens, and the connecting member is However, the present invention is not limited to this, and in the second embodiment of the present invention to be described below, the third lens barrel portion has first linear expansion coefficients different from each other. And a second cylindrical body member.

  A projection lens apparatus to which the second embodiment is applied will be described with reference to FIG. In addition, about the thing using the components similar to the said 1st Embodiment, a same sign is attached | subjected and description is abbreviate | omitted. A projection lens device 60 shown in FIG. 3 includes a projection lens system 13 including first to third lens groups 16 to 18, and a first lens barrel portion 19 in which the first to third lens groups 16 to 18 are respectively incorporated. A lens barrel 61 including a second barrel portion 20 and a third barrel portion 62, and a connecting member 63 are provided.

  The third barrel portion 62 includes a coupling member 64 connected to the coupling member 63, a lens holding member 65 that holds the third lens group 18, and an intermediate member 66 that couples the coupling member 64 and the lens holding member 65. It consists of. The third lens barrel 62 is composed of first and second cylindrical members that are located concentrically with the optical axis L1 and have different linear expansion coefficients, but the coupling member 64 and the lens holding member described above. 65 is a 1st cylindrical body member, and the intermediate member 66 is a 2nd cylindrical body member. Further, the front end of the coupling member 64 is coupled to the rear end of the second lens barrel portion 20.

In the present embodiment, the coupling member 64 and the lens holding member 65 as the first cylindrical body member are made of the same aluminum and have a linearity coefficient of 2.3 × 10 ⁻⁵ (/ ° C.), and the first cylindrical body. The intermediate member 66 as the second cylindrical body member having a larger linear expansion coefficient than the member is made of plastic and has a linear expansion coefficient of 7.0 ⁻⁵ (/ ° C.). The connecting member 63 is the same as that of the first embodiment. The same invar material is used, and the linear expansion coefficient is 0.14 × 10 ⁻⁵ (/ ° C.).

  The intermediate member 66 has a front end portion fixed to the front end of the lens holding member 65 by, for example, adhesion, and a rear end portion connected to the rear end of the coupling member 64 by, for example, screwing. The rear end of the coupling member 64 is disposed in alignment with the rear end of the lens holding member 65 and the end surface 18 a on the light source side of the third lens group 18.

  The connecting member 63 is fixed in a state where the front end is in contact with the light source side end surface 12 a of the mount portion 12, has a cylindrical shape extending from the mount portion 12 along the optical axis L <b> 1, and the rear end is coupled to the coupling member 64. . The coupling member 64 is formed with a protruding portion 64 a that protrudes perpendicular to the optical axis L <b> 1 at a position between the end surface 12 a of the mount portion 12 and the end surface 18 a of the third lens group 18. The coupling member 64 is fixed to the connecting member 63 by, for example, screwing the protruding portion 64a. When the temperature of the third lens barrel portion 62 rises, the coupling member 64 expands forward (screen side) with respect to the connecting member 63 and expands backward (light source side) with respect to the rear end side. The intermediate member 66 expands forward (screen side) with respect to the coupling member 64, and the lens holding member 65 expands backward (light source side) with respect to the intermediate member 66.

  In the third lens group 18, the focus position of the anomalous dispersion lens 22 is shifted backward by 70 μm with a temperature increase of 20 ° C. as in the first embodiment. In the second embodiment, since the third lens barrel 62 is composed of first and second cylindrical members having different linear expansion coefficients, the amount of movement of the anomalous dispersion lens 22 is the intermediate member 66 (second The connecting member 63 is further calculated from the difference between the amount of expansion / contraction of the cylindrical body member) to the screen side and the amount of expansion / contraction of the coupling member 64 and the lens holding member 65 (first cylindrical body member) to the light source side. It is equal to the value obtained by subtracting the expansion / contraction amount.

When determining the amount of movement of the anomalous dispersion lens 22, first, the axial dimension of the intermediate member 66 (second cylindrical member) must be considered. In the second embodiment, first, the coupling member 64 and the lens holding member 65 (first cylindrical body member) are expanded and contracted toward the light source, and the end surface 18a of the third lens group 18 is displaced to the intermediate member. 66 (second cylindrical body member) cancels out by expanding and contracting toward the screen, thereby regulating the position of the end surface 18a of the third lens group 18, and canceling out the above-described deviation amount of the focus position of the anomalous dispersion lens 22. Thus, the intermediate member 66 must be expanded and contracted so that the anomalous dispersion lens 22 moves forward by 70 μm when the temperature rises by 20 °. For this reason, the intermediate member 66 is made into the dimension calculated | required by the following formula | equation. B represents the axial dimension of the intermediate member 66.
((7.0 × 10 ⁻⁵ ) − (2.3 × 10 ⁻⁵ )) × 20 × B = 0.070 (2)
From the above equation (2), the axial dimension of the intermediate member 66 is B = 74.5 mm. By setting the axial dimension of the intermediate member 66 in this way, the intermediate member 66 expands and contracts to the screen side to offset the amount of expansion and contraction of the lens holding member 65 and the coupling member 64 to the light source side. The dimensions up to the rear end of the lens holding member 65, that is, the image-side end surface 18a of the third lens group 18 are regulated.

The difference between the amount of expansion / contraction that the intermediate member 66 (second cylindrical body member) expands / contracts to the screen side and the amount of expansion / contraction that the lens holding member 65 (first cylindrical body member) expands / contracts to the light source side is as follows: It is determined based on the difference in linear expansion coefficient (7.0 × 10 ⁻⁵ ) − (2.3 × 10 ⁻⁵ ) = 4.7 × 10 ⁻⁵ (/ ° C.). Further, the amount of movement of the anomalous dispersion lens 22 in the entire third lens barrel 62 is a value obtained by subtracting the amount of expansion / contraction of the coupling member 64 and the connecting member 63 from the amount of movement due to expansion / contraction of the intermediate member 66 and the lens holding member 65 ( That is, the expansion / contraction amount by which the intermediate member 66 (second cylindrical body member) expands and contracts to the screen side, and the expansion / contraction amount by which the coupling member 64 and the lens holding member 65 (first cylindrical body member) expand and contract to the light source side. From the difference, a value obtained by further subtracting the expansion / contraction amount of the connecting member 63). Therefore, Expression (3) for obtaining the dimension of the connecting member 63 is expressed as follows. C indicates the axial dimension of the connecting member 63.
((4.7 × 10 ⁻⁵ ) − (2.3 × 10 ⁻⁵ ) − (0.14 × 10 ⁻⁵ )) × 20 × C = 0.070 (3)
From the above equation (3), the axial dimension of the connecting member 63 is C = 155 mm.

  With the above configuration, as in the first embodiment, it is possible to correct a shift in the focus position of the anomalous dispersion lens 22 caused by a temperature change. Moreover, since the shape of the connecting member 63 made of an expensive invar material can be formed with a simpler shape than the first embodiment, further cost reduction can be achieved.

DESCRIPTION OF SYMBOLS 10,60 Projection lens apparatus 11 Housing | casing 12 Mount part 13 Projection lens system 14 Lens barrel 15,63 Connection member 18 3rd lens group (light source side lens group)
21, 62 Third lens barrel 22 Anomalous dispersion lens 25 Projector device 40 Screen 46 Light valve 64 Connecting member 65 Lens holding member 66 Intermediate member

Claims (4)

A projection lens system that enlarges and projects an image formed on a light valve onto a screen by light projected from a light source, and positive refraction is applied to a light source side lens group located closest to the light source in the projection lens system. A projection lens system including an anomalous dispersion lens having power;
A lens barrel that holds the projection lens system and is inserted to a position where at least a part of the lenses of the light source side lens group is arranged inside the housing through a mount provided in the housing of the projector device When,
The mount portion and the lens barrel are connected to regulate the size from the mount portion to the light source side end surface of the light source side lens group, and the amount of deviation of the focus position due to the temperature change of the anomalous dispersion lens And a connecting member made of an invar material in which an axial dimension from the mount portion is set so as to be offset by a movement amount of the anomalous dispersion lens caused by a temperature change of the lens barrel. Projection lens device.   The axial dimension of the connecting member is an expansion / contraction that expands / contracts due to a temperature change of the connecting member from an expansion / contraction amount in which the shift amount of the focus position due to the temperature change of the anomalous dispersion lens expands / contracts due to the temperature change of the lens barrel. 2. The projection lens apparatus according to claim 1, wherein the projection lens apparatus is set to be equal to a value obtained by subtracting the amount. The lens barrel includes first and second cylindrical body members having different linear expansion coefficients, and the first and second cylindrical body members are stacked concentrically with the optical axis of the light source side lens group. And the second cylindrical body member has a larger coefficient of linear expansion than the first cylindrical body member,
The axial dimension of the second cylindrical body member is such that the second cylindrical body member expands and contracts so as to offset the amount of displacement of the light source side end surface due to expansion and contraction of the first cylindrical body member. Is set to regulate the position of the light source side end face,
The axial dimension of the connecting member is such that the shift amount of the focus position due to the temperature change of the anomalous dispersion lens is the expansion / contraction amount by which the second cylindrical body member expands / contracts to the screen side due to the temperature change. The cylindrical body member is set to be equal to a value obtained by subtracting the expansion / contraction amount that expands and contracts due to the temperature change of the connecting member from the difference between the expansion and contraction amount that expands and contracts to the light source side due to temperature change. The projection lens device according to claim 1.   A projector apparatus comprising: a light source; a light valve; a housing in which these are housed; a housing provided with a mount; and the projection lens apparatus according to claim 1.

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