JP3930981B2 - Optical unit and projection display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention uses a light valve element such as a liquid crystal panel or a reflective video display element to project an image on a screen, for example, a liquid crystal projector apparatus, a reflective video display projector apparatus, a liquid crystal television, The present invention relates to a video display technology such as a projection display device.
[0002]
[Prior art]
2. Description of the Related Art There is known a projection display apparatus such as a liquid crystal projector that projects light on a liquid crystal panel by applying light from a light source such as a light bulb to a light valve element such as a liquid crystal panel.
This type of video display device adjusts light from a light source by changing it to light and dark for each pixel with a light valve element, and projects it onto a screen or the like. For example, a twisted nematic (TN) type liquid crystal display element, which is a typical example of a liquid crystal display element, has a polarization direction before and after a liquid crystal cell formed by injecting liquid crystal between a pair of transparent substrates having a transparent electrode film. The two polarizing plates are arranged so that they are different from each other by 90 °. By combining the action of rotating the polarization plane by the electro-optic effect of the liquid crystal and the selection of the polarizing component of the polarizing plate, Image information is displayed by controlling the amount of transmitted light. In recent years, in such a transmissive or reflective video display element, the element itself has been miniaturized and the performance such as resolution has been rapidly improved.
[0003]
For this reason, a display device using the image display element has been improved in size and performance, and not only simply performing image display by a video signal or the like as in the prior art, but also a projection image display device as an image output device of a personal computer. Has also been proposed. This type of projection-type image display device is particularly required to be small in size and to obtain bright images at every corner of the screen. However, the conventional projection-type video display device has a problem that it is large-sized or has insufficient performance such as brightness and image quality of the finally obtained image.
For example, to reduce the size of the entire liquid crystal display device, it is effective to reduce the size of the light valve, that is, the liquid crystal display element itself. If the liquid crystal display element is reduced in size with respect to the amount of luminous flux, the area irradiated by the illumination means is reduced, so the ratio of the luminous flux on the liquid crystal display element to the total luminous flux emitted by the light source (hereinafter referred to as light utilization efficiency) This causes problems such as lowering and darkness in the periphery of the screen. Furthermore, since the liquid crystal display element can use only polarized light in one direction, about half of the light from the light source that emits randomly polarized light is not used.
As a means for obtaining a bright image at the periphery of the screen, for example, there is an integrator optical system using two array lenses as described in JP-A-3-111806. The integrator optical system divides the light from the light source by a plurality of condensing lenses having a rectangular aperture shape constituting the first array lens, and the emitted light having each rectangular aperture shape is collected to each condensing lens having a rectangular aperture shape. Are superimposed on the irradiation surface (liquid crystal display element) by a second array lens constituted by a condenser lens group corresponding to the above. In this optical system, the intensity distribution of light irradiating the liquid crystal display element can be made substantially uniform.
[0004]
On the other hand, as an optical system for irradiating a liquid crystal display element with randomly polarized light from a light source aligned in one direction of polarization, a polarizing beam splitter as disclosed in JP-A-4-63318 is used. In some cases, random polarized light emitted from a light source is separated into P-polarized light and S-polarized light and synthesized using a prism.
However, in the conventional integrator optical system, since the rectangular diagonal size of one lens cell of the array lens is 0.25 ″ (inch) or more, brightness and image quality using a liquid crystal display element with a microlens or the like is used. In order to improve the uniformity of the illumination system, the F-number of the illumination system has to be set to approximately 2 to 3 and becomes longer with a distance of 31 mm or more between the first array lens and the second array lens. Therefore, it has been difficult to reduce the size of the optical system to the A4 file size in the conventional projection type liquid crystal display device, and also in the optical system using the polarization beam splitter, It was difficult to achieve precision matching with the array lens, and it was difficult to reduce the size of the lens, resulting in downsizing of the entire device and improved performance such as brightness. Furthermore, in the case of a projection-type liquid crystal display device, various factors such as the optical characteristics of the projection lens and the optical characteristics of the liquid crystal display element affect the image quality performance in addition to the illumination means. For this reason, it is difficult to obtain a display device with a small size and good image quality performance even if only the illumination means is improved. Light incident on the polarization optical path can be shielded, and unnecessary light that has conventionally caused a temperature rise of the polarizing plate in the vicinity of the image display element can be suppressed.
As described above, it is necessary to cope with the two aspects of improvement in brightness and image quality of the liquid crystal display device and miniaturization.
[0005]
[Problems to be solved by the invention]
Summarizing the above-mentioned issues in the prior art, there is a problem of how to ensure the brightness and image quality performance and miniaturization of the video display device. Issues related to brightness and image quality improvement and the size of the optical unit Matters related to the corresponding technology for downsizing the structure are problems. Furthermore, in order to ensure brightness, there is a problem of improving the bonding accuracy between optical components in order to reduce the boundary surface.
Another problem is to block the light incident on the S-polarized light path adjacent to the main optical path of the polarization beam combining means to suppress unnecessary light that has caused the temperature rise of the polarizing plate in the vicinity of the image display element.
An object of the present invention is to provide a projection-type image display technology that can ensure the brightness and the image quality and can be miniaturized with high precision and miniaturization with respect to the above-described problems in the conventional technology.
[0006]
[Means for Solving the Problems]
In the present invention, in an array lens composed of a plurality of condensing lens cells, the diagonal dimension of one lens cell is set to approximately 0.18 ″ or less.
As a result, it is possible to suppress an increase in the thickness of the array lens, the weight of the array lens can be reduced, and the amount of glass material is reduced, so that the manufacturing cost is also reduced.
[0007]
In addition, an image display element of a light valve means that forms an optical image corresponding to a video signal from light emitted from the light source unit, an illumination optical system that irradiates light on the image display element, and a projection that projects the emitted light An optical unit having means,
The illumination optical system includes:
A light source unit having a reflecting surface mirror and a plurality of condensing lenses provided in a size substantially equal to the exit aperture of the reflecting surface mirror, and condensing light emitted from the light source unit A first array lens for forming a secondary light source image and a plurality of condensing lenses are arranged in the vicinity of the secondary light source images to be formed. A second array lens that forms a lens image, and the diagonal dimension of the image display portion of the image display element is 0.7 ″ (inch), 0.9 ″, or 1.3 ″, At least the diagonal dimension of one lens cell of the first array lens is set to approximately 0.18 ″ or less.
With this configuration, the overall length of the optical unit can be shortened, and the size and weight can be reduced.
[0008]
In the present invention, the light emitted from the light source having a reflecting mirror having an exit aperture and having an electrode wire having a diameter of approximately 0.6 mm or less installed on one side of the lamp electrode in the reflecting mirror is provided. In a projection-type optical unit or image display device having an illumination optical system for irradiating the surface to be irradiated and a projection means for projecting light emitted from the image display element onto a screen,
The illumination optical system is composed of at least one reflecting mirror and a plurality of condensing lenses provided in a frame having a size substantially equal to the exit aperture of the reflecting mirror, and collects the light emitted from the light source unit. The first array lens for forming a plurality of secondary light source images and a plurality of condenser lenses are arranged in the vicinity where the plurality of secondary light source images are formed, A second array lens that forms individual lens images of one array lens, and a polarized beam that separates light from the first array lens or the second array lens into P-polarized light and S-polarized light A splitter, a λ / 2 phase difference plate for rotating any one of the polarization directions of the P-polarized light and the S-polarized light that are emitted from the polarization beam splitter, and any one of the P-polarized light and the S-polarized light To reflect polarized light And a composed polarized light combining means from the reflective portion,
The polarization combining unit is configured such that the central axis of each array of the polarization beam splitters has a pitch in the longitudinal array direction or the lateral array direction of the lens optical axes of each of the first array lens and the second array lens. And a plurality of polarization combining means are arranged, and the light of the reflecting prism of S-polarized light located at the center of the pitch of the lens optical axis of each of the first array lens and / or the second array lens A second array lens in which a light blocking member is added to the axis incident surface, that is, the surface of the second array lens on the side of the polarization combining unit is interposed between the light source and the image display element.
[0009]
With this configuration, it is possible to attach the light shielding film by providing the light shielding film attachment on the array lens side, which has conventionally been difficult to provide in the polarization beam combining means in the process of film deposition temperature. As a result, the light incident on the adjacent S-polarized light path can be shielded, and unnecessary light that has conventionally caused a temperature rise of the polarizing plate in the vicinity of the image display element can be suppressed.
[0010]
Further, in the projection-type image display device, at least one of the diagonal dimension, the vertical dimension, and the horizontal dimension of one lens cell in at least the first array lens or the second array lens is the above-described dimension. The video display element has a configuration that is approximately 1 / 4.5 or more than the corresponding diagonal dimension, vertical dimension, or horizontal dimension.
Alternatively, when the diagonal dimension of the video display portion of the video display element is 0.7 ″, 0.9 ″, or 1.3 ″, either the first array lens or the second array lens or A rectangular diagonal dimension of one lens cell in both is approximately 0.18 ″ or less.
[0011]
Alternatively, the diagonal dimension of one lens cell in either one or both of the first array lens and the second array lens is approximately 0.18 ″ or less.
Alternatively, in one or both of the first array lens and the second array lens, the total number of lens cells is approximately 240 or more.
Alternatively, the lens focal length of one lens cell of the first array lens and the second array lens is within 30 mm.
With this configuration, the size of the lens cell of the array lens can be reduced, the distance between the first array lens and the second array lens can be reduced, and the entire display device can be reduced in size using a small video display element. At the same time, it is possible to realize an image display apparatus that is bright and has a more uniform image quality over the entire screen.
[0012]
In addition, with this configuration, since the rectangular diagonal size of one lens cell of the array lens is approximately 0.18 ″ (inch) or less, uniformity of brightness and image quality using a liquid crystal display element with a microlens or the like. In order to improve the illumination system, when the F value of the illumination system is set to approximately 2 to 3, the distance between the first array lens and the second array lens can be shortened to a distance of 30 mm or less, and the optical system can be downsized. Can be achieved.
Therefore, the projection type liquid crystal display device can be downsized to A4 file size. Further, even in an optical system using a polarizing beam splitter, it is possible to align with an array lens with accuracy by pasting, and it is possible to simultaneously realize downsizing of the entire device and improvement in performance such as brightness.
[0013]
Furthermore, when the cell size is about 0.18 ″ or less, it is possible to make 7 to 8 cells uniform on the liquid crystal display element when the shadow of the electrode wire crosses, and in this case, the right and left of the center of the optical axis Since the electrode wire is present on one side, the array lens must have a horizontal array or a vertical array of at least 12 to 14. Therefore, since the number of cells is approximately 240 cells or more, the shadow of the electrode wire within approximately 0.6 mm is required. Can be prevented from being reflected on the liquid crystal display element, uniform image quality can be obtained, and the above problem can be easily solved.
Further, by setting the video display device to be approximately A4 file size or less, it can be housed in an attache case or the like, and can be a small, high-quality and high-brightness video display device suitable for carrying.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a first projection type liquid crystal display device according to the present invention.
In FIG. 1, the projection type liquid crystal display device has a light source 1, and the light source 1 is a white lamp such as an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, a mercury xenon lamp, or a halogen lamp. The light source 1 includes at least one reflecting mirror 5 having a circular or polygonal exit aperture, and an electrode wire 28 having a diameter of 0.6 mm or less installed on one side of the lamp electrode in the reflecting mirror. The light emitted from 1 passes through the liquid crystal display element 2 which is a light valve element, travels toward the projection lens 3 and is projected onto the screen 4.
[0015]
The light emitted from the light bulb of the light source 1 is collected by an elliptical, parabolic or aspherical reflector 5 and enters the first array lens 6. After passing through the first array lens 6, the light passes through the second array lens 7 and enters the polarization beam splitter 8. This incident light is separated by the polarization beam splitter 8, the transmitted light is separated into P-polarized light, and the reflected light is separated into S-polarized light. The P-polarized light is separated by a λ / 2 phase difference plate 9 disposed on the exit side surface of the polarization beam splitter 8. The polarization direction is rotated by 90 ° and becomes S-polarized light, which is incident on the condenser lens 10. The S-polarized light is repeatedly reflected, emitted from the exit surface of the adjacent polarized beam splitter 8, and enters the condenser lens 10. The condenser lens 10 has at least one structure, has a positive refractive power, has a function of further condensing the S-polarized light, and the light passing through the condenser lens 10 irradiates the liquid crystal display element 2. To do. An incident polarizing plate 11 that transmits S-polarized light is disposed on the incident side of the liquid crystal display element 2.
[0016]
In the conventional projection type liquid crystal display device, the incident light polarizing plate 11, the liquid crystal display element 2 and the output side polarizing plate 12 are combined so that only one direction of polarized light is transmitted, so that the amount of transmitted light is halved. However, since the polarizing beam splitter 8 is used in this embodiment, the polarization direction of random polarized light emitted from the light source 1 is aligned and incident on the liquid crystal display element 2, so that ideally, the conventional projection type liquid crystal display device is used. Double brightness is obtained.
[0017]
In the present embodiment, the first array lens 6 and the second array lens 7 of the present invention have the same shape, and the horizontal dimension of one lens cell is the horizontal dimension of the liquid crystal display element 2. For example, when the rectangular diagonal dimension of the image display unit of the liquid crystal display element 2 is 0.9 ″, the rectangular diagonal dimension of one lens cell is approximately 0.17 ″. Further, the total number of lens cells constituting the first array lens 6 and the second array lens 7 is approximately 240 cells or more, and the lens focal length of this one lens cell is within 30 mm. Therefore, the downsizing of the optical system can be achieved. In addition, individual images of approximately 240 cells or more overlap the liquid crystal display element 2, and a uniform image quality can be obtained as compared with the conventional apparatus. Furthermore, since the cell size is 0.17 ″, even when the shadow of the electrode wire 28 crosses the cell, it is approximately 240 cells (approximately 16 × 15 cells) or more, so that the image quality can be made uniform. Therefore, in the projection type liquid crystal display device, it is possible to simultaneously realize downsizing of the entire device and performance improvement such as brightness.
[0018]
Further, the polarization beam splitter 8 of the present invention is thinner in the optical axis direction than the second array lens 7, shortens the optical total length, reduces the weight of the optical unit, and increases the F value of the illumination system. There is an effect to. Thereby, since the F value of the projection lens 3 can be increased by linking to the illumination system, the projection lens 3 can be made small and light.
The light that has passed through the liquid crystal display element 2 passes through the projection means 3 such as a zoom lens and reaches the screen 4. The image formed on the liquid crystal display element 2 by the projection means 3 is enlarged and projected on a screen to function as a display device.
[0019]
Next, specific examples of the present invention will be described.
FIG. 2 is a configuration diagram of an embodiment of a projection type liquid crystal display device according to the present invention. The embodiment of FIG. 2 uses a total of three transmissive liquid crystal display elements 2 as liquid crystal light valves corresponding to the three primary colors R (red), G (green), and B (blue). A three-plate projection display device is shown. In this embodiment, light emitted from a lamp 13 such as an ultra-high pressure mercury lamp, which is a light source, is reflected by the parabolic reflecting mirror reflector 5 and then substantially the same as the emission opening of the parabolic reflecting mirror reflector 5. Consists of a plurality of condensing lenses provided in a rectangular frame of the same size, condenses the light emitted from the lamp unit 14, and enters the first array lens 6 for forming a plurality of secondary light source images Furthermore, it is composed of a plurality of condensing lenses, is arranged in the vicinity of the above-described plurality of secondary light source images, and forms individual lens images of the first array lens 6 on the liquid crystal display element 2. Passes through the second array lens 7. The emitted light is incident on a row of rhomboid prisms of approximately ½ size of each lens width arranged so as to match the pitch in the horizontal direction of each lens optical axis of the second array lens 7. The prism surface is provided with a polarizing beam splitter 8. The incident light is separated into P-polarized light and S-polarized light by the polarizing beam splitter 8. The P-polarized light passes through the polarization beam splitter 8 as it is, and the polarization direction is rotated by 90 ° by the λ / 2 phase difference plate 9 provided on the exit surface of this prism, and is converted into S-polarized light and emitted. The On the other hand, the S-polarized light is reflected by the polarization beam splitter 8, reflected once again in the original optical axis direction in the adjacent rhomboid prism, and then emitted as S-polarized light. Thereafter, the light is condensed on the liquid crystal display element 2 by the condenser lens 10. On the way, the light emitted from the polarization beam splitter 8 is bent at 90 ° by the total reflection mirror 15 and is disposed at an angle of 45 ° with respect to the optical axis. B (blue) and G (green) reflection dichroic mirrors 16, R (red) light is transmitted and B and G light is reflected. The transmitted R light beam is bent by 90 ° by the R total reflection mirror 17, passes through the condenser lens 18 in front of the liquid crystal display element and the incident polarizing plate 11, and is composed of a counter electrode, liquid crystal, and the like. 2, and passes through an output polarizing plate 12 provided on the light output side of the liquid crystal display element 2.
[0020]
The liquid crystal display element 2 is provided with a number of liquid crystal display units corresponding to the pixels to be displayed (for example, three colors each having 800 horizontal pixels and 600 vertical pixels). Then, the polarization angle of each pixel of the liquid crystal display element 2 changes according to a signal driven from the outside, and finally the light having a direction that coincides with the polarization direction of the output polarizing plate 12 is emitted and becomes an orthogonal direction. Light is absorbed by the output polarizing plate 12. The amount of light passing through the polarizing plate and the amount absorbed by the polarizing plate are determined by the relationship between the polarization angle of the output polarizing plate 12 and the light having the polarized light at this halfway angle. In this way, an image according to a signal input from the outside is projected.
The R light beam emitted from the output polarizing plate 12 is reflected by the dichroic prism 19 having the function of reflecting the R light beam, enters the projection means 3 such as a zoom lens, and is projected on the screen.
[0021]
On the other hand, the B light and G light transmitted through the B and G transmissive dichroic prism 19 enter the G reflecting dichroic mirror 20, and the G light is reflected by this mirror, and the liquid crystal display element front condenser lens 18 and the incident polarizing plate 11 are reflected. It passes through, enters the liquid crystal display element 2, and passes through an output polarizing plate 12 provided on the light output side of the liquid crystal display element 2. The G light beam emitted from the output polarizing plate 12 is transmitted through the dichroic prism 19 having the function of transmitting the G light beam, is incident on the projection lens 3, and is projected on the screen.
The B light beam that has passed through the G reflecting dichroic mirror 20 passes through the relay lens 21, its optical path is bent by 90 ° by the total reflecting mirror 22, passes through the relay lens 21, and then passes through the relay lens 21. It is bent and passes through the condenser lens 18 in front of the liquid crystal display element and the incident polarizing plate 11, enters the liquid crystal display element 2, and passes through the output polarizing plate 12 provided on the light emission side of the liquid crystal display element 2. The B light emitted from the output polarizing plate 12 is reflected by the dichroic prism 19 having a function of reflecting the B light, then enters the projection lens 3 and is projected on the screen.
[0022]
As described above, the light beams corresponding to R, G, and B are separated and synthesized by the color separation unit and the color synthesis unit, and the image on the liquid crystal display element 2 corresponding to each of R, G, and B is enlarged by the projection lens 3. Then, an image of each color is synthesized on the screen and an enlarged real image is obtained. In the figure, they are arranged like a power supply circuit 24 and a video signal circuit 25 and have the effect of guiding heat generated by the light source 1 to the outside by the blower fan 26. Further, in this embodiment, since the light emitted from the random light source is aligned in one direction by the polarization combining means, the incident polarizing plate generates less heat.
[0023]
Further, the light source and the projection unit are arranged so that their optical axes are orthogonal to each other, and further, through a color separation / synthesis unit comprising the color separation unit, the liquid crystal display element, and the color synthesis unit. By arranging the power supply circuit 24 and the video signal circuit 25 as shown in the figure, the entire apparatus can be reduced in size.
In the present embodiment, the first array lens 6 and the second array lens 7 of the present invention have the same shape, and the horizontal dimension of one lens cell is the horizontal dimension of the liquid crystal display element 2. For example, when the rectangular diagonal dimension of the image display portion of the liquid crystal display element 2 is 0.9 ″, the ratio of the first array lens 6 and the second array lens 7 is approximately 1 / 5.3. The rectangular diagonal dimension of one lens cell is approximately 0.17 ″, the total number of lens cells constituting the first array lens 6 and the second array lens 7 is approximately 240 cells or more, The lens focal length of one lens cell of the one array lens 6 and the second array lens 7 is 30 mm or less, and the optical system can be downsized. In addition, individual images of approximately 240 cells or more overlap the liquid crystal display element 2, and a uniform image quality can be obtained as compared with the conventional apparatus. Further, since the cell size is 0.17 ″, even when the shadow of the electrode wire 28 crosses the cell, the image quality can be made uniform if it is approximately 240 cells (approximately 16 × 15 cells) or more. In the projection type liquid crystal display device, it is possible to simultaneously realize downsizing of the entire device and performance improvement such as brightness.
[0024]
Further, when trying to improve the uniformity of brightness and image quality using a liquid crystal display element with a microlens, etc., the F value of the illumination system has to be set to approximately 2 to 3; The distance between the first array lens and the second array lens of the invention can be shortened to a distance of 30 mm or less, and the optical system can be miniaturized.
[0025]
Furthermore, in the present invention, the polarization combining means is combined, and the thickness of the polarization beam splitter 8 as the polarization combining means is made thinner than that of the second array lens 7 (that is, the second array lens 7 is 2). In the case of about 0.5 ± 0.5 mm, the polarization beam splitter 8 should be 2 mm or less), so that the optical path length can be shortened, and the total reflection mirror 15 can be placed close to each other, and the set can be downsized. Become.
[0026]
In the embodiment of the present invention shown in FIG. 2, the illumination optical system includes a lamp unit 14, a first array lens 6, a second array lens 7, a polarization beam splitter 8, a λ / 2 phase difference plate 9, and a condenser lens 10. Means a light path before the light from the lamp 13 is separated into R, G, and B light. Further, the optical unit includes an illumination optical system, and further, the light from the illumination optical system is R, G, B using a B (blue), G (green) reflective dichroic mirror 16, a G reflective dichroic mirror 20, and the like. And the separated R, G, and B light incident on the respective liquid crystal display elements 2, reflect the R and B light, and transmit the G light. In some cases, the optical path to the projection means 3 through the prism 19 is indicated.
[0027]
FIG. 3 is a diagram showing a partial effect of the first embodiment according to the present invention.
FIG. 3 shows an illumination optical system of a projection-type liquid crystal display device. The light source 1 has a circular reflecting mirror 5 and the diameter installed on one side of the lamp electrode in the reflecting mirror 5 is substantially the same. The electrode wire 28 is within 0.6 mm.
The light emitted from the light bulb of the light source 1 is collected by an elliptical, parabolic or aspherical reflector 5 and enters the first array lens 6. After passing through the first array lens 6, the light passes through the second array lens 7 and enters the polarization beam splitter 8. The incident light is separated by the polarizing beam splitter 8 into the transmitted light is P-polarized light, and the reflected light is separated into S-polarized light. The P-polarized light is separated by the λ / 2 phase difference plate 9 disposed on the exit side surface of the polarizing beam splitter 8. The polarization direction is rotated by 90 ° and becomes S-polarized light, which is incident on the condenser lens 10. The S-polarized light is repeatedly reflected, emitted from the exit surface of the adjacent polarized beam splitter 8, and enters the condenser lens 10. The condenser lens 10 has at least one structure, has a positive refractive power, has a function of further condensing the S-polarized light, and the light passing through the condenser lens 10 irradiates the liquid crystal display element 2. To do.
[0028]
In FIG. 3, in this embodiment, the first array lens 6 and the second array lens 7 of the present invention have the same shape, and the lateral dimension of one lens cell is the liquid crystal display element 2. For example, when the rectangular diagonal dimension of the image display portion of the liquid crystal display element 2 is 0.9 ″, the first array lens 6 and the second array The rectangular diagonal dimension of one lens cell of the lens 7 is approximately 0.17 ″, and the total number of lens cells constituting the first array lens 6 and the second array lens 7 is 240 cells or more. (FIG. 3 is a schematic diagram) Since the lens focal length of one lens cell of the first array lens 6 and the second array lens 7 is within 30 mm, the optical system can be miniaturized. . Further, as shown by the dotted lines in FIG. 3, individual images of 240 cells or more are superimposed on the liquid crystal display element 2, and uniform image quality can be obtained as compared with the conventional apparatus. In addition, since the cell size is 0.17 ″, even if the shadow of the electrode wire 28 crosses the cell, if it is approximately 240 cells (approximately 16 × 15 cells) or more, there will be 8 rows from 7 on one side, 0.17 ″ cell size. Then, if six strip-shaped shadows having a width of approximately 0.6 mm are arranged, one cell size is obtained. Therefore, if there are at least six rows of cells on one side, the brightness caused by the shadow of the electrode wire 28 on the liquid crystal display element. Therefore, it is possible to make the image quality uniform by eliminating the unevenness of color. In this case, since the electrode wires exist on the left and right sides of the center of the optical axis, if the horizontal or vertical array of the array lens has a margin of 1 to 2 or more, at least 14 to 16 or more columns are required. Therefore, if the number of cells is approximately 240 cells or more, the shadow of the electrode wire within approximately 0.6 mm is reflected on the liquid crystal display element to be uniform as shown by the oblique lines in the figure, and the image quality is uniform in brightness and darkness. Is obtained.
Therefore, in the projection type liquid crystal display device, it is possible to simultaneously realize downsizing of the entire device and performance improvement such as brightness. Furthermore, since the first array lens 6 and the second array lens 7 have the same shape, only one type of mold can be used, and costs can be reduced.
[0029]
FIG. 4 is a diagram showing a second embodiment according to the present invention.
The polarizing beam splitter 8 in FIG. 4 has a configuration in which a polarizing beam splitter film that separates light P-polarized light and S-polarized light is attached to a glass plate material, which is bonded to a laminate and then sliced at 45 °. . For this reason, as shown in FIG. 4, it has a plate-like configuration in which several longitudinal rhombus prisms are arranged. This film deposition may be performed by mirror deposition of aluminum or silver every other surface. However, since this mirror portion has a role of reflecting S-polarized light, it is necessary to devise a method for preventing light from entering the prism optical path.
[0030]
For this reason, the polarizing beam splitter 8 of the present invention has an optical axis incident surface of the reflecting prism of the S-polarized light located at the center of the optical axis pitch of each lens of the second array lens 7, that is, the second array lens 7. The light shielding member 27 is added to the side surface, and when the unnecessary light is cut and absorbed and cut by the incident polarizing plate 11, there is an effect of preventing heat generated by energy conversion from light to heat. This light shielding member 27 is composed of a slit-like reflective film formed by deposition of silver or aluminum vapor deposited film, a frosted glass-like divergent film, a light-shielding metal seal, a heat-resistant seal, a metal plate with slits, or It consists of metal plating.
[0031]
In the plate-like configuration in which several polarization beam splitters 8 are arranged as described above, λ / 2 phase difference plates 9 are bonded every other row, and the separated P-polarized light is converted into S-polarized light. The light emitted from the polarization beam splitter 8 is aligned with the S-polarized light, or is reflected and emitted from the prism adjacent to the prism on which the separated S-polarized light is incident. It is also possible to align the light emitted from the polarization beam splitter 8 with P-polarized light.
[0032]
A plurality of rhombus prisms of the flat polarizing beam splitter 8 as described above are arranged in conformity with the pitch in the lateral arrangement direction of the optical axes of the lenses of the second array lens 7, and the second array is arranged. The lens 7 is divided into left and right or upper and lower halves of the second array lens 7 with a gap, for example, a gap h having a width of ½ of the optical axis pitch, at the center of the lens 7, and symmetric with respect to the center. Then, if the polarizing beam splitter 8 and another one of the same polarizing beam splitter 8 are bonded together with the optical axis as the center and inverted by 180 °, the light blocking member 27 provided on the second array lens 7 and the polarized light are polarized. The second array lens 7, the light shielding member 27, and the polarization beam splitter 8, which are difficult to manufacture, can be applied to the pitch in the horizontal arrangement direction of the beam splitter 8 with high accuracy. Fast-growing can be achieved.
[0033]
Conventionally, as shown in FIG. 4B, a symmetric flat plate-shaped polarizing beam splitter 8 is manufactured by a manufacturer, and the interface between the optical components of the polarizing beam splitter 8 and the second array lens 7 is an air layer. In this case, even if an antireflection film is applied to the interface, the light transmission efficiency is lowered. Therefore, the polarizing beam splitter 8 and the second array lens 7 are connected to the optical axis of each lens and the side of the polarizing beam splitter 8. It was the structure which matched and matched the pitch of the arrangement direction. At this time, a slit-shaped light shielding plate for cutting unnecessary light is arranged in front of the second array lens 7, that is, on the light source side, and unnecessary light components before being incident on the polarization beam splitter 8, the hatched portion in the figure. It was the structure which shields light. However, in this case, the light shielding member 27 is a structural member such as a metal plate provided with a slit, and the light shielding member has to be supported independently of the optical axis.
For this reason, due to the component accuracy error and the assembly accuracy error of the light shielding member 27, the necessary light may be shielded, and the number of components increases at the time of assembly.
[0034]
However, in the present invention, the polarizing beam splitter 8 is bonded to the second array lens 7 provided with the light shielding member 27 in a bilaterally symmetrical manner with the center as a boundary, and the light shielding member is formed by a vapor deposition film or the like. The incident surface of the prism can be shielded with almost no error, and the number of parts is small, and the assemblability is improved.
Further, according to the present invention, a symmetric flat plate-shaped polarizing beam splitter 8 as in the prior art is manufactured by a manufacturer, and then the two-stage processing step of bonding to the second array lens 7 is not performed. Since the polarizing beam splitter 8 is bonded to the second array lens 7 in a single step, the processing cost can be reduced.
[0035]
Further, since the conventional polarizing beam splitter 8 is integrated on the left and right, the bonding accuracy is stacked from the left end to the right end, and when it is bonded to the second array lens 7, it is divided into the center, and the right and left bonding accuracy errors, for example, ± 0.25 appears on both the left and right sides.
However, according to the present invention, since the polarization beam splitter 8 is bonded to the second array lens 7 provided with the left and right separate light blocking members 27, the accuracy error from the center is not accumulated, and the left polarization beam splitter is not accumulated. Since the center of the left side or the lens optical axis in the left half of the second array lens 7 having a large amount of light can be used as the center of the accuracy distribution, the number 8 is a combination of ± 0.125. It can be suppressed to accuracy error. Similarly, when the right polarization beam splitter 8 is bonded to the second array lens 7, there is also an effect that the bonding accuracy error can be halved in the same manner as the above left side. As a result, the positional deviation of the optical axis due to the bonding error of the polarization beam splitter 8 having a width of ½ the lens optical axis pitch of the second lens array 7 is reduced, and the incident light from the second array lens 7 is converted into the polarized beam. The amount of vignetting is reduced by the splitter 8. As a result, the light transmission efficiency is improved, and the brightness performance can be improved.
[0036]
【The invention's effect】
As described above, the projection-type image display apparatus of the present invention can achieve a downsized optical system, and has an effect that the entire apparatus can be downsized to an A4 file size or less. In addition, in an optical system using a polarizing beam splitter, it is possible to perform alignment with an array lens with high accuracy, and performance improvement such as brightness can be realized simultaneously with downsizing of the entire apparatus.
Furthermore, when the cell size is about 0.18 ″ or less and the number of cells is about 240 cells or more, the shadow of the electrode wire can be prevented from being reflected on the liquid crystal display element, and uniform image quality can be obtained.
Moreover, in the structure which provides a light-shielding member, unnecessary light is cut by this and heat generation can be prevented.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a projection type liquid crystal display device showing a first embodiment of the present invention.
FIG. 3 is a diagram showing the effect of the first embodiment of the present invention.
FIG. 4 is a diagram showing a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Image display element, 3 ... Projection lens, 5 ... Reflector, 6 ... 1st array lens, 7 ... 2nd array lens, 8 ... Polarizing beam splitter, 9 ... (lambda) / 2 phase difference plate, DESCRIPTION OF SYMBOLS 10 ... Condenser lens, 11 ... Incident polarizing plate, 12 ... Output polarizing plate, 27 ... Light-shielding member, 28 ... Electrode wire.

Claims (10)

An optical unit comprising a light source for emitting light, and the image display device in which an optical image is formed the light from the light source according to a video signal, and a projection means for projecting light from said image display element,
At least one reflecting mirror having a rectangular, circular or polygonal exit aperture;
A said reflecting plane mirror, a light source having an electrode wire located in the lamp electrodes,
A plurality of cells having a rectangular shape, the shadow of the electrode wire traverses at least one of the cells, and the plurality of cells each collect light from the light source to form a plurality of secondary light source images; A first array lens that is approximately the same size as the exit aperture ;
A second array lens having a plurality of cells having a rectangular shape and disposed in the vicinity of the plurality of secondary light source images to form the plurality of secondary light source images on the video display element ; Have
The horizontal width value of one cell of the first array lens is smaller than the value obtained by multiplying the value of the band-like shadow width of the electrode wire by the number of arrays in the vertical direction of the first array lens. Or the vertical width value of one cell of the first array lens is multiplied by the band-like shadow width value of the electrode wire and the arrangement number of the half in the horizontal direction of the first array lens. An optical unit characterized by being smaller than the value .   At least a diagonal dimension, a vertical dimension, or a horizontal dimension of one lens cell of the first array lens is ¼ of a diagonal dimension, a vertical dimension, or a horizontal dimension of the image display element. The optical unit according to claim 1, wherein the ratio is equal to or greater than .5. The diagonal dimension of the video display portion of the video display element is 0.7 inches, 0.9 inches, or 1.3 inches, and at least the diagonal dimension of one cell of the first array lens is 0.18 inches or less. The optical unit according to claim 1. The optical unit according to claim 1, wherein a diagonal dimension of one cell of the first array lens and / or the second array lens is 0.18 inches or less. The optical unit according to claim 1, wherein the total number of cells constituting at least one of the first array lens and the second array lens is 240 cells or more. A light source that emits light, a video display element that is a light valve means for forming an optical image according to a video signal from the light emitted from the light source, a projection means that projects light emitted from the video display element, A projection type display device comprising display means for displaying the projection light from the projection means,
At least one reflecting mirror having a rectangular, circular or polygonal exit aperture;
A said reflecting plane mirror, a light source having an electrode wire located in the lamp electrodes,
A plurality of cells having a rectangular shape, the shadow of the electrode wire traverses at least one of the cells, and the plurality of cells each collect light from the light source to form a plurality of secondary light source images; A first array lens that is approximately the same size as the exit aperture ;
A second array lens having a plurality of cells having a rectangular shape and disposed in the vicinity of the plurality of secondary light source images to form the plurality of secondary light source images on the video display element ; Have
The width of one cell of the first array lens is smaller than the value obtained by multiplying the value of the band-like shadow width of the electrode wire by the number of arrays in the longitudinal direction of the first array lens. Or the vertical width value of one cell of the first array lens is multiplied by the band-like shadow width value of the electrode wire and the arrangement number of the half in the horizontal direction of the first array lens. A projection type display device characterized by being smaller than the value .   At least a diagonal dimension, a vertical dimension, or a horizontal dimension of one lens cell of the first array lens is ¼ of a diagonal dimension, a vertical dimension, or a horizontal dimension of the image display element. The projection display device according to claim 6, wherein the ratio is 0.5 or more. The diagonal dimension of the video display portion of the video display element is 0.7 inches, 0.9 inches, or 1.3 inches, and at least the diagonal dimension of one cell of the first array lens is 0.18 inches or less. The projection display device according to claim 6. The projection type display device according to claim 6, wherein a diagonal dimension of one cell of the first array lens and / or the second array lens is 0.18 inches or less. The projection display device according to claim 6, wherein the total number of cells constituting at least one of the first array lens and the second array lens is 240 cells or more.

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