JP2005055801A - Projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the blur of a projected picture caused by the temperature change of the back focus of a projection lens. <P>SOLUTION: In the projection type display device making light emitted from a light valve 105 incident on the projection lens 106 and projecting it, an attaching part 106-A attached to the end of the projection lens 106 and a mount member are connected through a back focus correction member 121. When ambient temperature rises, the back focus correction member 121 is expanded according to a thermal expansion coefficient and its length becomes large. When the ambient temperature rises, the attaching part 106-A is pressed by the expansion of the back focus correction member 121, and the lens 106 is displaced to an opposite side to the light valve 105 with respect to the mount member 111, then optical path length between the projection lens 106 and the light valve 105 becomes large, so that the change of the back focus of the projection lens 106 caused by the temperature change is corrected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projection display device.

  An example of a projection display device having a configuration in which light incident on a light valve and emitted from the light valve is incident on a projection lens via an optical member such as a prism and projected will be described with reference to FIG.

  FIG. 9 is a conceptual diagram showing a cross section of a conventional projection display device.

In this projection type display device, the light source light passes through the polarizing beam splitter 102 which is a prism member, is incident on the reflective light valve 101 integrally attached to the polarizing beam splitter 102, and is modulated by the reflective light valve 101. The light enters the polarizing beam splitter 102, and the modulated light is detected and transmitted as transmitted light by the polarizing beam splitter 102, enters the projection lens 105, and is projected onto a screen (not shown). As shown in FIG. 9, the projection lens 105 is attached to a mount member 107 attached to the floor member 106. Further, the lower surface portion of the polarization beam splitter 102 which is a prism member to which the light valve 101 is attached is fixed to the integrated attachment member 103 with an adhesive. The end portion of the integrated attachment member 103 is bent, and the bent portion is fixed to the mount member 107.
JP 2001-249403 A

  The light valve 101 and an image on a screen (not shown) are optically conjugate with respect to the projection lens 105 that projects the light emitted from the light valve 101, and the light valve 101 and the projection lens 105 are between them. The projection lens 105 is designed and manufactured so that the conjugate relationship is established between the back focus, which is the optical path length, and the optical path length between the projection lens 105 and the screen.

  By the way, the value of the back focus changes depending on the environmental temperature. Normally, the back focus value increases as the ambient temperature rises.

  However, as shown in FIG. 9, since the projection lens 105 is fixed to the mount member 107, the distance between the light valve 101 and the projection lens 105 cannot be changed, and the conjugate relationship is not maintained, There is a problem that the projected image is blurred.

  The present invention has been made in view of such circumstances, and the problem is to eliminate the blur of the projected image caused by the change in the back focus temperature of the projection lens.

  The projection display device according to claim 1, wherein in the projection display device that projects the light emitted from the light valve by being incident on the projection lens, a change in the rear focal position of the projection lens due to a temperature change is performed. It has a correction member which correct | amends by changing the distance of a projection lens and the said light valve.

  The projection display device according to claim 2, further comprising a mount member that fixes the projection lens via the correction member in the projection display device according to claim 1, and the correction member expands due to a temperature rise. Thus, the rear focal position is moved and corrected in a direction approaching the projection lens.

  The projection display device according to claim 3, further comprising a mount member for fixing the projection lens via the correction member, wherein the correction member expands due to a temperature rise. Thus, the rear focus position is corrected by moving in the direction away from the projection lens.

  A projection display device according to a fourth aspect is characterized in that the projection display device according to the second aspect is connected to the projection lens side of the mount member.

  The projection display device according to claim 5 is the projection display device according to claim 3, wherein the correction member is connected to the light valve side of the mount member.

  The projection display device according to claim 6 is the projection display device according to any one of claims 1 to 5, wherein the rear focal position changes in a direction away from the projection lens due to a temperature rise. Features.

  The projection display device according to claim 7 is the projection display device according to claim 1, 3 or 5, wherein the rear focal position changes in a direction approaching the projection lens due to a temperature rise. .

  The projection display device according to claim 8 is the projection display device according to any one of claims 1 to 7, wherein the light valve is provided for each color light obtained by color-separating light from a light source into a plurality of wavelengths. A reflection-type light valve arranged, and further comprising a polarization beam splitter for detecting modulated light emitted from the reflection-type light valve, and a color combining optical system for color-combining each of the detected color lights. It is characterized by.

  As described above, according to the present invention, it is possible to eliminate the blur of the projected image caused by the temperature change of the back focus of the projection lens.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view for explaining the basic structure of a projection display device according to the first embodiment of the present invention.

  A parallel light source light emitted from a light source 101 composed of a lamp and a parabolic concave mirror is converted into polarized light having a vibration direction in a direction perpendicular to the paper surface through a polarization conversion illumination device 102, and time-series color separation is performed. The optical system 103 performs color separation into R (red) light, G (green) light, and B (blue) light in time series. The color separation optical system 103 has a disk shape that rotates about a central axis O, and the disk shape is divided into three equal parts in the circumferential direction to transmit R light, G light, and B light, respectively. Is formed. Each color light separated by the color separation optical system 103 enters the polarization beam splitter 104 in time series along the same optical axis, is reflected in the time series by the polarization separation unit, and is a reflection type light arranged on the exit surface side. The light enters the valve 105. Each color light incident on the light valve 105 is modulated and reflected and emitted by a color signal, enters the polarization beam splitter 104, detects only the modulated light as transmitted light, takes it out, enters the projection lens 106, and is not shown. Enlarge and project on the screen.

  The light valve 105 and the projected image on the screen are optically conjugate with respect to the projection lens 106, and the light beam emitted from one point on the light valve 105 with a predetermined numerical aperture (NA) is projected to the projection lens 106. And imaged at a conjugate point on the screen. The optical path length between the projection lens 106 and the light valve 105 at the rear focal position of the projection lens 106 is called back focus (rear focal length).

  FIG. 2 is a perspective view of the projection display device according to the first embodiment.

  FIG. 2 shows an optical member constituting an optical path from the light valve 105 to the projection lens 106. The lower surface of the polarization beam splitter 104 to which the light valve 105 is attached to a predetermined side surface is fixed on the attachment member 112. The attachment member 112 is fixed to the mount member 111 to which the projection lens 106 is attached. An attachment portion 106 -A for attaching to the mount member 111 using a plurality of back focus correction members 121 is provided on the side surface portion of the lens barrel portion of the projection lens 106. As shown in FIG. 2, the attachment portion 106 -A and the mount member 111 are connected via four back focus correction members 121. Both ends of the back focus correction member 121 are fixed to the attachment portion 106-A and the mount member 111 using screws.

  The mount member 111 to which the projection lens 106 and the polarization beam splitter 104 are attached by the above method is attached to the floor portion 113 (see FIG. 3) of the projection display device. Although not shown, the light source 101, the polarization conversion illumination device 102, and the color separation optical system 103 are arranged on the floor 113.

  FIG. 3 is a conceptual diagram showing a cross section of the projection display device according to the first embodiment.

  The back focus correction member 121 has a predetermined thermal expansion coefficient with respect to the temperature. When the environmental temperature rises, the back focus correction member 121 expands according to the thermal expansion coefficient, and its length increases. Due to the expansion of the back focus correction member 121, the attachment portion 106-A of the projection lens 106 attached to the end thereof is pushed, and the projection lens 106 is displaced to the opposite side of the light valve 105 with respect to the mount member 111 to project. The optical path length between the lens 106 and the light valve 105 is increased. When the projection lens 106 has a characteristic that the value of the back focus increases with increasing temperature, the material of the back focus correction member 121 so that the light valve 105 is arranged near the changed back focus position. And the length is determined.

  According to the first embodiment, even if the environmental temperature changes and the back focus value of the projection lens 106 changes, the light valve 105 is arranged near the back focus position of the projection lens 106 according to the change. Therefore, it is possible to eliminate the blur of the projected image due to the back focus temperature change.

  FIG. 4 is a plan view for explaining the basic configuration of a projection display apparatus according to the second embodiment of the present invention.

  The light source light emitted from the light source 201 enters the polarization conversion illumination device 202, is converted into polarized light having a vibration direction perpendicular to the paper surface, travels, reflects the B light, and the R light and G light. The reflected dichroic mirror 203RG that reflects the mixed light and the light is incident on the cross dichroic mirror 203 arranged so as to be orthogonal to each other, and the B light traveling in the opposite direction to the mixed light of the R light and the G light. Color separation is performed. The color-separated B light travels while changing the traveling direction by the deflecting mirror 204, enters the polarization beam splitter 207B, is reflected by the polarization separation unit, and enters the reflective light valve 208B.

  The mixed light of the color-separated R light and G light travels while changing the traveling direction by the deflecting mirror 205, enters the G light reflecting dichroic mirror 206, and travels through the reflected G light and the transmitted R light. And are incident on the polarization beam splitters 207G and 207R arranged for each color light, reflected by the polarization separation units, and incident on the reflection type light valves 208G and 208R, respectively.

  Each color light incident on each color light valve 208R, 208G, 208B is modulated and reflected / emitted by a color signal, and the modulated light is detected and transmitted as transmitted light by polarization beam splitters 207R, 207G, 207B. The analyzing light of each color light enters the cross dichroic prism 209 constituting the color synthesis optical system from different incident surfaces, the R light is reflected by the R light reflecting dichroic film 209R, and the B light is reflected by the B light reflecting dichroic film 209B. The reflected G light passes through both films, is color-combined, and exits from the exit surface. The combined light enters the projection lens 210, and a full-color image is projected on a screen (not shown).

  FIG. 5 is a perspective view of a projection display device according to the second embodiment.

  FIG. 5 shows an optical member constituting an optical path from the reflection light valves 208R, 208G, 208B for the respective color lights to the projection lens. The polarizing beam splitters 207R, 207G, and 207B, each having the reflection type light valves 208R, 208G, and 208B attached to predetermined side surfaces, are respectively disposed on predetermined side surfaces of the cross dichroic prism 209 across the auxiliary optical plate-shaped members 211R, 211G, and 211B. It is fixed with an adhesive and integrated with the cross dichroic prism 209.

  An auxiliary plate member 231 is fixed to the lower surface of the cross dichroic prism 209 with an adhesive. The lower surface of the supported plate member 231 is fixed to the upper surface of the attachment member 212 attached to the mount member 213 to which the projection lens 210 is attached.

  The method of attaching the projection lens 210 to the mount member 213 is the same as in the first embodiment. An attachment portion 210 -A that is attached to the mount member 213 using the back focus correction member 221 is formed on the side surface of the lens barrel portion of the projection lens 210. Unlike the first embodiment, the attachment portion 210-A has a quadrangular shape. One end of the back focus correction member 221 is fixed to the four corners of the attachment portion 210-A with screws, and the other end is fixed to the mount member 213 with screws.

  The mount member 213 is fixed to the floor (not shown) of the projection display device with screws.

  As in the first embodiment, when the environmental temperature changes and the temperature rises, the back focus value of the projection lens 210 increases. However, the material of the back focus correction member 221 has a positive thermal expansion coefficient with respect to temperature. Therefore, the length of the back focus correction member 221 increases, and the optical path length from the projection lens 210 to the light valves 208R, 208G, and 207B increases. Accordingly, a plurality of light valves 208R, 208G, and 208B can be disposed near the changed back focus position.

  According to this 2nd Embodiment, there exists an effect similar to 1st Embodiment.

  FIG. 6 is a perspective view of a projection type display apparatus according to the third embodiment of the present invention. The parts common to the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  This embodiment is different from the second embodiment in that it can be applied when the temperature characteristic of the back focus is a characteristic in which the back focus value decreases as the temperature rises.

  In this embodiment, the attachment portion 210 -B is formed on the side surface of the lens barrel portion of the projection lens 210, and the attachment portion 210 -B and the mount member 213 to which the projection lens 210 is attached are fixed using the focus correction member 222. The attachment part 210-B is attached to a part of the barrel close to the incident surface of the projection lens 210. Further, the attachment portion 210-B is disposed on the light valve 208R, 208G, 208B side with respect to the mount member 213, which is the incident surface side to the projection lens 210 on the cross dichroic prism 209 side from the mount member 213. The projection lens 210 is fixed to the mount member 213 by fixing the attachment portion 210 -B to the mount member 213 using the back focus correction member 222.

  As described above, the back focus value of the projection lens decreases with increasing temperature. When the environmental temperature rises, the back focus correction member 222 expands and becomes longer in accordance with its own positive expansion coefficient due to the temperature rise, and the projection lens 210 is made optical such as the light valves 208R, 208G, and 208B according to the amount of displacement. It moves to the side where the member is placed and changes its position. Accordingly, a plurality of light valves 208R, 208G, and 208B can be disposed near the changed back focus position. The material and length of the back focus correction member 222 are determined so that the light valves 208R, 208G, and 208B are disposed near the back focus position of the projection lens 210.

  The attachment member 212 to which the modules of the light valve 208G, the polarization beam splitter 207G, and the cross dichroic prism 209 are attached has a long length from the mount member 213. Since the mounting member 212 expands according to a positive temperature coefficient with respect to the normal temperature, its influence cannot be ignored. Therefore, in this embodiment, the material and length of the back focus correction member 222 are determined in consideration of the expansion coefficient of the attachment member 212.

  This third embodiment also has the same effect as the first embodiment.

  FIG. 7 is a plan view for explaining the basic structure of a projection display apparatus according to the fourth embodiment of the present invention.

  The light source light emitted from the light source 301 is converted into polarized light having a vibration direction in a direction parallel to the paper surface and perpendicular to the optical axis by the polarization conversion illumination device 302, enters the polarization rotation element 303, and changes the vibration direction of only G light. The light is converted into a direction perpendicular to the paper surface, enters the polarization beam splitter 304, and is color-separated into G light reflected by the polarization separation unit and mixed light of R light and B light transmitted through the polarization separation unit. The color-separated B light enters the polarization beam splitter 305, is reflected by the polarization separation unit, and enters the reflective light valve 308G.

  The mixed light of R light and B light transmitted through the polarization beam splitter 304 enters the polarization rotation element 306, converts only the R light into polarized light having a vibration direction in a direction perpendicular to the paper surface, and enters the polarization beam splitter 307. Then, it is color-separated into R light reflected by the polarization separation unit and B light transmitted therethrough, and enters the reflection type light valves 308R and 308B, respectively.

  Each color light incident on the light valves 308R, 308G, and 308B for each color light is modulated by a color signal and reflected and emitted. The G light emitted from the light valve for G light 308G enters the polarization beam splitter 305, and enters the polarization beam splitter 310 that detects the modulated light as transmitted light and extracts and synthesizes the color.

  The R light emitted from the R light valve 308R enters the polarization beam splitter 307, and the modulated light is detected and transmitted as transmitted light. The B light emitted from the B light valve 308B enters the polarization beam splitter 307, and the modulated light is detected and reflected as reflected light. The polarization beam splitter 307 combines the R light detection light and the B light detection light. The combined light enters the polarization conversion element 309, changes the vibration direction of the R light to a direction perpendicular to the paper surface, becomes the same as the vibration direction of the B light, enters the polarization beam splitter 310, and is reflected by the polarization separation unit. Then, it is color-combined with the G light that passes through the polarization separation unit, and exits from the exit surface. The combined light enters the projection lens 311 and a full color image is projected on a screen (not shown).

  FIG. 8 is a perspective view of a projection display device according to the fourth embodiment.

  The projection lens 311 is attached to the mount member 313, and other constituent members are formed integrally with the mount member 313 and are respectively disposed on the floor member 314 orthogonal to the mount member 313. Although not shown, the light source 301 and the polarization conversion illumination device 302 are disposed on the extended surface of the floor member 314.

  When the optical member constituting the projection display device is arranged on the floor member 314 as in this embodiment, there is a problem that the position of the optical member is greatly shifted due to the thermal expansion coefficient of the floor member 314. . In this embodiment, when the back focus value of the projection lens 311 increases as the temperature rises, the back focus position becomes closer to the projection lens 311 side in front of the positions of the light valves 308G, 308R, and 308B. Can respond.

  The method for attaching the projection lens 311 to the mount member 313 in which the back focus value increases as the temperature rises is the same as in the previous embodiment. The mounting portion 311 -A formed on the lens barrel on the incident surface side of the combined light and the mount member 313 are fixed by using the back focus correction member 312, and the length is increased by the thermal expansion coefficient of the back focus correction member 312 when the temperature rises. By increasing the height, the projection lens 311 is moved in the direction in which optical members such as the light valves 308G, 308R, and 308B are arranged with respect to the mount member 313 on the incident surface side. Although the positions of the light valves 308G, 308R, and 308B for each color light are displaced by the temperature rise, the distance away from the projection lens 311 is larger than the back focus value, so that the projection lens 311 is adjusted to correct the difference. The position of the light valves 308G, 308R, and 308B is corrected to the back focus position of the projection lens 311 by moving to the side.

  According to this 4th Embodiment, there exists an effect similar to 1st Embodiment.

FIG. 1 is a plan view for explaining the basic structure of a projection display device according to the first embodiment of the present invention. FIG. 2 is a perspective view of the projection display device according to the first embodiment. FIG. 3 is a conceptual diagram showing a cross section of the projection display device according to the first embodiment. FIG. 4 is a plan view for explaining the basic configuration of a projection display apparatus according to the second embodiment of the present invention. FIG. 5 is a perspective view of a projection display device according to the second embodiment. FIG. 6 is a perspective view of a projection display device according to a third embodiment of the present invention. FIG. 7 is a plan view for explaining the basic structure of a projection display apparatus according to the fourth embodiment of the present invention. FIG. 8 is a perspective view of a projection display device according to the fourth embodiment. FIG. 9 is a conceptual diagram showing a cross section of a conventional projection display device.

Explanation of symbols

101, 201, 301 Light source 102, 202, 302 Polarization conversion illumination device 103 Color separation optical system 104, 207R, 207G, 207B, 304, 305, 307, 310 Polarization beam splitter (optical member)
105, 208R, 208G, 208B, 308R, 308G, 308B Reflective light valve (light valve)
106, 210, 311 Projection lens 106-A, 210-A, 210-B, 311-A Mounting portion 111, 213, 313 Mounting member 112, 212 Mounting member 113, 214, 314 Floor member 121, 221, 312 Back focus Correction member 203 Cross dichroic mirror 204, 205 Deflection mirror 206 Dichroic mirror 209 Cross dichroic prism 303, 306, 309 Polarization rotating element

Claims (8)

In the projection type display device that projects the light emitted from the light valve by entering the projection lens,
A projection display device comprising a correction member that corrects a change in a rear focal position of the projection lens due to a temperature change by changing a distance between the projection lens and the light valve.   It further includes a mount member for fixing the projection lens via the correction member, and the correction member expands as the temperature rises, whereby the rear focal position is moved and corrected in a direction approaching the projection lens. The projection display device according to claim 1.   It further includes a mount member for fixing the projection lens via the correction member, and the correction member expands due to a temperature rise, thereby moving and correcting the rear focal position in a direction away from the projection lens. The projection display device according to claim 1.   The projection display device according to claim 2, wherein the correction member is connected to the projection lens side of the mount member.   4. The projection display device according to claim 3, wherein the correction member is connected to the light valve side of the mount member.   6. The projection display device according to claim 1, wherein the rear focal position changes in a direction away from the projection lens due to a temperature rise.   6. The projection display device according to claim 1, wherein the rear focal position changes in a direction approaching the projection lens due to a temperature rise.   The light valve is a reflective light valve disposed for each color light obtained by color-separating light from a light source into a plurality of wavelengths, and a polarizing beam splitter for analyzing modulated light emitted from the reflective light valve; The projection display device according to claim 1, further comprising: a color synthesis optical system that performs color synthesis of the detected color lights.

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