JP2006235642A - Projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type display device excellent in illuminance uniformity and color uniformity on a screen and using one image forming means. <P>SOLUTION: The projection type display device includes: a plurality of light sources 30 and 31 for radiating light in nearly the same light emitting cycle and in light emitting timing different from each other; a color separation means 42 for separating the light from the light source by every specified wavelength band at every time interval; one image forming means 39 for forming an optical image in accordance with a video signal; an illumination means 43 for condensing the light from the color separation means so as to illuminate the image forming means; and a projection lens 40 for projecting the optical image on the image forming means onto a screen. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projection display apparatus that irradiates an image formed on an image forming unit with illumination light and enlarges and projects it onto a screen by a projection lens.

  Projection type that illuminates light from a light source on a small image forming means that forms an optical image according to a video signal, and projects and enlarges the optical image on a screen by a projection lens in order to obtain a large screen image A display device is used.

  As an image forming means, an active matrix type liquid crystal panel having a configuration in which polarizing plates are arranged in crossed Nicols on both sides of a twisted nematic type liquid crystal cell and modulating light using polarized light is widely practical. It is used for.

  As an illumination device that illuminates light from a light source on a liquid crystal panel, two lens array plates composed of a plurality of lenses are used (for example, JP-A-3-111806). The two lens array plates divide a light beam incident on one of the lens array plates arranged on the light source side into a large number, and superimpose the divided light beams on the liquid crystal panel to illuminate efficiently and uniformly.

  In addition, as an illumination device for a projection display device using a liquid crystal panel using polarized light, a polarization separation prism as a polarization separation means and a half-wave plate as a polarization rotation means are used, so that the polarization direction of natural light is uniform. An illumination device is disclosed that constitutes a polarization conversion optical member that converts light into a direction, improves the light use efficiency of the projection display device, and increases the brightness of the projection display device (see, for example, Patent Document 1). .

  Furthermore, an illumination device using a plurality of light sources is disclosed in order to increase the brightness of the projection display device (see, for example, Patent Document 2).

  FIG. 21 shows a schematic configuration of a projection display device in which an illumination device 900 using a plurality of conventional light sources is introduced.

  Radiated light from the two discharge lamps 901 and 902 which are light sources is condensed by respective concave mirrors (parabolic mirrors) 903 and 904 and converted into light beams of substantially parallel light. Each parallel light beam is converged by the positive lens 905 and enters the color separation device.

  In the color separation device, green, red, and blue dichroic mirrors are attached to a rotating plate 906 that is rotated by a motor 907, and light emitted from the positive lens 905 passes through the color separation device, so that the green color is time-divisionally divided. , Red, and blue.

  The light beam emitted from the color separation device enters the condenser lens 908 and is converted into a substantially parallel light beam. Each of the parallel light beams enters the first lens array plate 909. The first lens array plate 909 is composed of a plurality of rectangular lenses, and the incident light beam is divided into a large number by each rectangular lens and converges on each of the plurality of lenses of the second lens array plate 910. A large number of minute light source images are formed on each lens of the second lens array plate 910. The second lens array plate 910 superimposes the light flux from each lens of the first lens array plate 909 on the liquid crystal panel 911. In this way, a large number of divided light beams are superimposed on the liquid crystal panel 911 to perform uniform illumination.

  The field lens 912 collects illumination light for the liquid crystal panel 911 on the pupil plane 914 of the projection lens 913. Light emitted from the liquid crystal panel 911 enters the projection lens 913. The projection lens 913 enlarges and projects an image of the liquid crystal panel 911 on a screen (not shown).

  According to the above configuration, since a plurality of light sources are used, a projection display device having a bright image can be configured.

FIG. 22 shows an outline of the appearance of the light source image formed on the pupil plane 914 of the projection lens 913. Light from the two light sources 901 and 902 is divided into a plurality of minute light source images 924 by the lens array plates 909 and 910, and these light source images 924 form two light source image groups 922 and 923.
JP-A-8-304739 JP-A-6-265887

  Generally, in order to improve the image brightness of a projection display device, it is sufficient to increase the power consumption of the discharge lamp of the light source. However, if the power consumption is increased while ensuring the life of the discharge lamp, the light emission There is a problem that the portion becomes large and the light utilization efficiency is lowered. For this reason, the brightness of the projection display device can be improved more efficiently by using a plurality of light sources with relatively low power consumption.

  In the configuration of the conventional illumination device using a plurality of light sources as shown in FIG. 21, the two light sources 901 and 902 are symmetrical with respect to the optical axis of the projection lens 913 (hereinafter sometimes referred to as the system optical axis). Is arranged. In such a case, the images from the light source formed on the pupil plane 914 of the projection lens are formed as two groups across the optical axis, as shown in FIG.

  In general, the projection lens has vignetting, and the illuminance around the screen is reduced with respect to the center illuminance on the screen. This is because vignetting occurs in the light source image on the pupil plane of the projection lens due to vignetting. Therefore, when the light emission characteristics of the two light sources arranged with the optical axis in between are different, the light source images contributing to the brightness of the periphery of the screen are different, resulting in uneven color of the projected image on the screen. Further, when one light source is not lit, there is a problem that the illuminance distribution on the screen becomes non-uniform. Therefore, when a lighting device and a projection display device are configured using a plurality of light sources, the light source image on the pupil plane of the projection lens formed by each light source needs to be as symmetric as possible with respect to the optical axis. Met.

  In addition, when light rays from multiple light sources are incident on a single color separation device, the spectral transmission characteristics of the dichroic mirror that performs color separation have an incident angle dependency. When the incident angle increases, the transmission band becomes the reference. The wavelength purity of the transmitted light is significantly lowered. As a result, the color reproducibility of the projected image is significantly reduced instead of being brightened. On the other hand, when a plurality of color separation devices are used, the set is remarkably increased in size and lacks practicality.

  Further, the first and second lens array plates are required for the two concave mirrors, respectively, which causes a problem that the cost is increased.

  In addition, when a plurality of light sources are used, particularly when the light source is AC lighting, the light emission intensity varies from time to time for each light source, so that a phenomenon occurs in which the brightness of the screen fluctuates as superimposed illumination.

  The present invention solves the above-described conventional problems, and in a lighting device using a plurality of light sources, the light source image is uniformly arranged with respect to the system optical axis, the light use efficiency is high, and the size is small. An object is to provide a low-cost light source device.

  It is another object of the present invention to provide a projection display device that is excellent in illuminance uniformity and color uniformity on a screen, has high luminance, has good color reproducibility, is small, and is low in cost.

  In order to achieve the above object, the present invention is configured as follows.

  That is, the illumination device according to the first configuration of the present invention is an illumination device that illuminates an image forming unit that collects light from a light source to form an image, and includes a plurality of light sources and the plurality of light sources. Each of the radiated light is collected and reflected in a predetermined direction, and is composed of a plurality of prisms. The prism array plate for depolarizing and synthesizing the light from the reflection means, and the prism array plate A color separation unit that separates light into specific wavelength bands every time; a light collecting unit that receives light from the color separation unit and controls the light flux density of the incident light to emit substantially parallel light; A first lens array plate that divides the light from the condensing means into a plurality of light beams, and a second lens on which light from the first lens array plate is incident. With a lens array plate To.

  An illumination device according to a second configuration of the present invention is an illumination device that illuminates an image forming unit that collects light from a light source and forms an image, and includes a plurality of light sources and the plurality of light sources. Each of the radiated light is collected and reflected in a predetermined direction, and is composed of a plurality of prisms. The prism array plate for depolarizing and synthesizing the light from the reflection means, and the prism array plate A color separation unit that separates light into specific wavelength bands every time; a light collecting unit that receives light from the color separation unit and controls the light flux density of the incident light to emit substantially parallel light; A first lens array plate that divides the light from the condensing means into a plurality of light beams, and a second lens on which light from the first lens array plate is incident. Lens array plate and the second lens A polarization separation unit that separates light from the ray plate into two polarized light beams having orthogonal polarization directions, and a polarization rotation unit that aligns the polarization directions of the two polarized light beams emitted from the polarization separation unit. And

  An illumination device according to a third configuration of the present invention is an illumination device that illuminates an image forming unit that collects light from a light source and forms an image, and includes a plurality of light sources and the plurality of light sources. Consists of a reflecting means for condensing radiated light and reflecting it in a predetermined direction, and a plurality of prisms, a first prism array plate for deflecting the light from the reflecting means, and a plurality of prisms. The second prism array plate that deviates and synthesizes the light from the first prism array plate, and the color that separates the light from the second prism array plate for each specific wavelength band every time A light separating unit; a light collecting unit that receives light from the color separating unit; controls light flux density of incident light to emit substantially parallel light; and a plurality of lenses. The first lens assembly that divides the light into a number of light beams Lee and plate is composed of a plurality of lenses, the light from the first lens array plate is characterized in that a second lens array plate incident.

  An illumination device according to a fourth configuration of the present invention is an illumination device that illuminates an image forming unit that collects light from a light source to form an image, and includes a plurality of light sources and the plurality of light sources. Consists of a reflecting means for condensing radiated light and reflecting it in a predetermined direction, and a plurality of prisms, a first prism array plate for deflecting the light from the reflecting means, and a plurality of prisms. The second prism array plate that deviates and synthesizes the light from the first prism array plate, and the color that separates the light from the second prism array plate for each specific wavelength band every time A light separating unit; a light collecting unit that receives light from the color separating unit; controls light flux density of incident light to emit substantially parallel light; and a plurality of lenses. The first lens assembly that divides the light into a number of light beams The second lens array plate, which is composed of a plate and a plurality of lenses, and the light from the first lens array plate is incident thereon, and the light from the second lens array plate are orthogonally polarized 2 A polarization separation unit that separates into two polarized lights and a polarization rotation unit that aligns the polarization directions of the two polarized lights emitted from the polarization separation unit are provided.

  According to the above illumination device, the illumination device can illuminate the liquid crystal panel uniformly and efficiently with the light from the plurality of light sources by providing the prism array plate that deflects and combines the light from the plurality of light sources. Can be realized.

  The projection display apparatus according to the present invention includes an image forming unit that forms an optical image according to a video signal, an illumination unit that collects light from a light source and illuminates the image forming unit, and the image A projection display device comprising a projection lens that projects an optical image on the forming means onto a screen, wherein the illumination means is any one of the first to fourth illumination devices.

  According to the above projection display device, a bright projection display device with good uniformity and high light utilization efficiency can be configured.

  According to the illuminating device of the present invention, by providing a prism array plate that deflects and synthesizes light from a plurality of light sources, the light from the plurality of light sources can illuminate a liquid crystal panel very efficiently and uniformly. A device can be realized.

  Further, according to the projection display device of the present invention, a bright projection display device with good uniformity and high light utilization efficiency can be configured.

  Hereinafter, an illumination device and a projection display device of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a schematic configuration of an illumination device and a projection display device according to a first embodiment of the present invention. The projection display apparatus according to the present embodiment uses a liquid crystal panel that modulates light using polarized light or scattering as an image forming unit.

  In FIG. 1, 30 and 31 are discharge lamps, 32 and 33 are parabolic mirrors, 34 is a prism array plate composed of a plurality of prisms, 44 is a positive lens, and 42 is a color wheel composed of a plurality of dichroic mirrors. , 43 is a condenser lens, 35 is a first lens array plate, 36 is a second lens array plate, 37 is an illumination device of the present embodiment, 38 is a field lens, 39 is a liquid crystal panel, 40 is a projection lens, and 41 is A pupil plane 58 of the projection lens is an optical axis of the projection lens 40.

  Light emitted from the lamps 30 and 31 such as a metal halide lamp, an ultra-high pressure mercury lamp, and a xenon lamp is collected by the corresponding parabolic mirrors 32 and 33, respectively, and forms an angle of 120 degrees with respect to the optical axis 58. It is converted into substantially parallel light. Each light beam enters a prism array plate 34 composed of a plurality of prism elements. The prism elements of the prism array plate 34 are triangular prisms having an apex angle of 60 degrees. Each prism element of the prism array plate 34 totally reflects the light incident from the parabolic mirrors 32 and 33 and deviates each optical axis by 60 degrees. The light beams from the parabolic mirrors 32 and 33 are divided into a plurality of parts by the prism array plate 34, and the divided light beam from the parabolic mirror 32 and the divided light beam from the parabolic mirror 33 are alternated. Is synthesized. The light beams synthesized alternately are converged by the positive lens 44 and then incident on the color wheel 42 which is composed of a plurality of dichroic mirrors and is rotated at high speed by the motor 45.

  FIG. 2 shows a schematic configuration of the color wheel 42. Reference numerals 50, 51, and 52 denote dichroic filters that transmit red, green, and blue, respectively, and are configured by dividing a circle into three and combining three color filters. The motor 45 rotates once while an image for one frame is displayed on the liquid crystal panel 39.

  The light incident on the color wheel 42 is separated into red, green, and blue color lights in time series by the red transmissive dichroic filter 50, the green transmissive dichroic filter 51, and the blue transmissive dichroic filter 52.

  Light converged by the positive lens 44 and incident on the color wheel 42 diverges and is separated into red, green, and blue color light and enters the condenser lens 43.

  FIG. 3 is a conceptual diagram of the light flux density control of the incident light flux at the condenser lens 43. The operation of the condenser lens 43 will be described with reference to FIG. For example, an aspheric double-sided convex lens is used as the condenser lens.

  The condenser lens 43 converts incident light into substantially parallel light. At this time, as shown in FIG. 3, the incident light flux is divided into four from the side near the optical axis 58, and the respective light flux densities are S1, S2, S3, and S4, and the light flux in each region of the outgoing light flux corresponding to each incident light flux. When the density is SS1, SS2, SS3, SS4, the condenser lens 43 controls the incident light flux so that S1 <SS1, S2 <SS2, S3 = SS3, S4> SS4 and SS1> SS2> SS3> SS4. Then exit. As a result, the condensing lens 43 emits a parallel light beam having a smaller light beam density as the distance from the optical axis 58 increases.

  The light flux from the condenser lens 43 is incident on the first lens array plate 35 composed of a plurality of lenses. The prism element pitch of the prism array plate 34 is twice the lens element pitch of the first lens array plate 35 (pitch in the arrangement direction of the prism elements). This is because the boundary of the light beam reflected by one side of the prism of the prism array plate 34 does not coincide with the opening of the lens element of the first lens array plate 35.

  In this way, the light beam divided by the prism array plate 34 is uniformly incident on the light beam incident on the lens elements of the first lens array plate 35 so that the liquid crystal panel 39 can be illuminated uniformly.

  FIG. 4 shows a configuration example of the first lens array plate 35. (A) is a front view, (B) is a side view, and (C) is a bottom view. As shown in the figure, the first lens array plate 35 is configured by two-dimensionally arranging a plurality of rectangular lenses, and the shape of each rectangular lens is similar to each pixel of the liquid crystal panel 39 that is an illuminated area. To do.

  The light beam incident on the first lens array plate 35 is divided into a number of light beams. A large number of minute light beams divided by the first lens array plate 35 converge on the corresponding lenses of the second lens array plate 36 composed of a plurality of lenses. A large number of light emitter images (secondary light source images) corresponding to the light emitters of the light sources 30 and 31 are formed on the second lens array plate 36. As the second lens array plate 36, for example, the same one as the first lens array plate can be used.

  The focal length of the lens elements of the first lens array plate 35 is equal to the distance between the first lens array plate 35 and the second lens array plate 36. Further, the focal length of the lens elements of the second lens array plate 36 is determined so that the first lens array plate 35 surface and the liquid crystal panel surface 39 have a substantially conjugate relationship. In order to illuminate the liquid crystal panel 39 with the light emitted from each lens element of the second lens array plate 36, each lens element of the second lens array plate 36 and each lens element of the first lens array plate 35 are appropriately set. Eccentric.

  A large number of light beams emitted from the second lens array plate 36 are superimposed on the liquid crystal panel 39 to illuminate the liquid crystal panel 39 uniformly.

  The field lens 38 is for condensing the light that illuminates the liquid crystal panel 39 on the pupil plane 41 of the projection lens 40. The focal length of the field lens 38 is set so that the pupil plane 41 of the projection lens 40 and the second lens array plate 36 have a substantially conjugate relationship.

  FIG. 5 schematically shows a state in which the light emitter image of the pupil surface 41 of the projection lens 40 is viewed from the exit surface side. At the same time, the second lens array plate 36 is shown by dotted lines so that the correspondence between the second lens array plate 36 and each rectangular lens can be understood. Corresponding to each rectangular lens, two light emitter images 54 and 55 corresponding to the light sources 30 and 31 are formed. The density of the light beam incident on the first lens array 35 decreases as the distance from the optical axis 58 decreases due to the action of the condensing lens 43, so that the size of the light emitter images 54 and 55 decreases as the distance from the optical axis 58 increases.

  In FIG. 5, in order to use all the light rays emitted from the second lens array plate 36, the projection lens 40 having a pupil plane having a size equal to the circumscribed circle 56 of the effective area of the second lens array plate 36 is necessary. become. However, in order to reduce the size and cost of the projection lens, the pupil plane should be as small as possible. In the present embodiment, the illuminator images 54 and 55 become smaller the further away from the optical axis 58 due to the action of the condensing lens 43, so that even if the peripheral illuminant image is not captured, there is no significant loss. Therefore, if the pupil plane is the virtual circle 57, the projection lens 40 can be reduced in size and cost can be reduced while suppressing light loss.

  Light source images of the light sources 30 and 31 similar to those shown in FIG. 5 are formed on the pupil plane 41 of the projection lens 40. That is, minute light source images of the light sources 30 and 31 are alternately formed in the arrangement direction of the prism elements of the prism array plate 34, respectively.

  This pupil plane 41 is projected on a screen (not shown) as a light source. In the present embodiment, two light source images are formed symmetrically with respect to the optical axis as compared with the light source image on the pupil plane of the projection lens of the conventional illumination device shown in FIG. In addition, a light source image is formed on the entire pupil plane of the projection lens. Therefore, an image with excellent illuminance uniformity can be obtained.

  The prism array plate 34 may be manufactured by molding. By using a molded product, a low-cost prism array plate can be configured. In this case, the accuracy of the apex angle of the prism and the accuracy of the flat surface portion are lowered, but the loss is only slightly increased. The prism array plate 34 may be made of a resin having high heat resistance. If the prism array plate is made of resin, the cost can be further reduced.

  Even if the dichroic filter constituting the color wheel 42 has an incident angle dependency, the incident angle can be changed by adjusting the power of the positive lens 44. In addition, by configuring the positive lens 44 from two lens groups, the distance between the prism array plate 34 and the color wheel 42 can be varied. As a result, color reproducibility can be optimized.

  As described above, according to the present embodiment, the light from the plurality of light sources 30 and 31 is deflected by the prism array plate 34 and synthesized, so that the light source image formed on the pupil plane 41 of the projection lens 40 is obtained. An illuminating device which is arranged almost symmetrically with respect to the optical axis 58, has good illuminance uniformity and color uniformity on the screen, and has high light utilization efficiency can be configured. In addition, since a plurality of light sources can be combined without reducing the F-number of the projection lens 40, a compact and low-cost projection display device can be configured.

(Embodiment 2)
FIG. 6 shows a schematic configuration of the illumination device and the projection display device according to the second embodiment of the present invention. Members having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The projection display apparatus according to the present embodiment uses a liquid crystal panel that modulates light using polarized light as an image forming unit.

  The configuration from the lamps 30 and 31 to the condenser lens 43 is the same as that of the first embodiment shown in FIG. The present embodiment differs from the first embodiment (FIG. 1) in that the illumination device 60 of the present embodiment includes a polarization separation prism array 61 as polarization separation means and a half-wave plate as polarization rotation means. 65 and an auxiliary lens 66.

  FIG. 7 shows a configuration example of the polarization separation prism array 61 and the half-wave plate 65. (A) is a front view, (B) is a side view, and (C) is a bottom view. The polarization separation prism array 61 is configured by arranging a plurality of polarization separation prisms 62 in a direction perpendicular to the arrangement direction of the lamps 30 and 31.

  The polarization separation prisms 62 are arranged at a pitch that is approximately ½ of the arrangement pitch of the lens elements of the second lens array 36 in the minor axis direction. A polarization separation film 63 is disposed on the joint surface of the polarization separation prism 62. Further, a half-wave plate 65 is arranged on the output side of the polarization separation prism array 61 at an arrangement pitch twice that of the polarization separation prism.

  The operation of the polarization separation prism array 61 and the half-wave plate 65 will be described with reference to FIG.

  A large number of light beams emitted from the second lens array plate 36 enter a polarization separation prism array 61 in which a plurality of minute polarization separation prisms 62 are arranged in one direction perpendicular to the prism arrangement direction of the prism array plate. The minute polarization splitting prisms 62 are arranged at a pitch of about ½ of the arrangement pitch of the lens elements of the second lens array plate 36. The light incident on one polarization splitting prism 62a is transmitted through the polarization splitting film 63a as P-polarized light and reflected as S-polarized light. The reflected S-polarized light is incident on the adjacent reflection film 63 b and reflected again, and is incident on the half-wave plate 65. The half-wave plate 65 is disposed so as to rotate the polarization direction of incident light by 90 °, and converts incident S-polarized light into P-polarized light and transmits it.

  Light obtained by converting natural light into light of one polarization direction by the polarization separation prism array 61 and the half-wave plate 65 enters the auxiliary lens 66. A number of light beams refracted by the auxiliary lens 66 are superimposed on the liquid crystal panel 38 to illuminate the liquid crystal panel 38 uniformly.

  As described above, by arranging the polarization separation prism array 61 and the half-wave plate 65, it is possible to use the lost light in one polarization direction while aligning the polarization direction in one direction. The effective polarized light flux to illuminate is increased.

  The field lens 38 is for condensing the light illuminated on the liquid crystal panel 39 on the pupil plane 41 of the projection lens 40. The focal length of the field lens 38 is set so that the pupil plane 41 of the projection lens 40 and the second lens array plate 36 have a substantially conjugate relationship.

  The auxiliary lens 66 is a lens for illuminating the light beam emitted from the periphery of the second lens array plate 36 on the liquid crystal panel 39, and the focal length is the distance between the auxiliary lens 66 surface and the liquid crystal panel 39 surface. .

  FIG. 9 schematically shows a state in which the illuminant image of the pupil plane 41 of the projection lens 40 is viewed from the exit surface side. At the same time, the second lens array plate 36 is shown by dotted lines so that the correspondence between the second lens array plate 36 and each rectangular lens can be understood. As the light source images of the light sources 30 and 31, P-polarized light and S-polarized light emitter images are alternately formed on the pupil plane 41 in the prism arrangement direction (vertical direction in FIG. 9) of the polarization separation prism array 61. In order to obtain a pupil plane with no loss, the size of the circumscribed circle 56 of the effective area of the second lens array plate 36 is required as in the case of FIG. 5, but the size of the pupil 41 is set to a virtual circle. By setting it to 57, the projection lens 40 can be reduced in size and cost while minimizing light loss.

  As described above, according to the present embodiment, the light from the plurality of light sources 30 and 31 is deflected by the prism array plate 34 and synthesized, so that the light source image formed on the pupil plane 41 of the projection lens 40 is obtained. An illuminating device which is arranged almost symmetrically with respect to the optical axis 58, has good illuminance uniformity and color uniformity on the screen, and has high light utilization efficiency can be configured. In addition, since a plurality of light sources can be combined without reducing the F-number of the projection lens 40, a compact and low-cost projection display device can be configured. Furthermore, since a polarization conversion optical member that converts natural light into unidirectionally polarized light is disposed, an illumination device with very high light utilization efficiency can be configured.

(Embodiment 3)
FIG. 10 shows a schematic configuration of the illumination device and the projection display device according to the third embodiment of the present invention. Members having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The projection display apparatus according to the present embodiment uses a liquid crystal panel that modulates light using polarized light or scattering as an image forming unit.

  The configuration from the lamps 30 and 31 to the positive lens 44 and the configuration from the first lens array plate 35 to the liquid crystal panel 39 are the same as those in the first embodiment shown in FIG. This embodiment is different from the first embodiment (FIG. 1) in that an incident side lens 71 and an emission side lens 72 are arranged as a condensing means in place of the condensing lens 43 of the first embodiment. The configuration of the color wheel as the color separation means is different. In FIG. 10, reference numeral 70 denotes a lighting device of the present embodiment.

  Similarly to the first embodiment, the light converged by the positive lens 44 is made up of a plurality of dichroic mirrors and enters a color wheel 73 that is rotated at high speed by a motor 74.

  FIG. 11 shows the configuration of the color wheel 73 of the present embodiment. Reference numerals 50, 51, and 52 denote red transmissive, green transmissive, and blue transmissive dichroic filters, respectively. Reference numeral 53 denotes a visible light transmissive filter. Unlike the first embodiment, the color wheel 73 of the present embodiment combines a three-color filter by dividing a circle into six parts, and further combines white that is used where the brightness of the screen is high. Further, the motor 74 rotates twice while displaying one frame of red, green, blue, and white images on the liquid crystal panel 39. Thereby, even when an image moving at a high speed is displayed, deterioration in image quality can be reduced.

  The light emitted from the prism array plate 34 is converged by the positive lens 44 and enters the color wheel 73. The light incident on the color wheel 73 is red, green, blue, and white in time series by the red transmitting dichroic filter 50, the green transmitting dichroic filter 51, the blue transmitting dichroic filter 52, and the visible light transmitting filter 53. Separated into colored light. The red, green, blue, and white color lights are collected by the incident side lens 71 and the emission side lens 72, converted into substantially parallel light, and then incident on the first lens array plate 35 including a plurality of lenses.

  FIG. 12 is a conceptual diagram for explaining the control of the incident light beam by the entrance side lens 71 and the exit side lens 72.

  The incident side lens 71 has, for example, a flat incident surface, a strong positive power at the periphery on the exit side, and a gradual power near the optical axis 58 as compared to the periphery. Therefore, incident light travels straight in the vicinity of the optical axis 58 with almost no change in traveling direction, but is largely refracted and converted into substantially parallel light in the peripheral part.

  Further, for example, the exit side lens 72 has a flat entrance surface, and the exit surface has a strong positive power near the optical axis 58, and has a gentle power at the periphery compared to the vicinity of the optical axis. Accordingly, the incident light is not subjected to the refraction action at the peripheral portion, and the light beam travels straight, and is converted into substantially parallel light by the refraction action in the vicinity of the optical axis 58. Accordingly, substantially parallel light is emitted from both the vicinity and the periphery of the optical axis.

  At this time, as shown in FIG. 12, the incident light flux is divided into four from the side near the optical axis 58, and the respective light flux densities are S1, S2, S3, and S4. Assuming that the light flux density is SS1, SS2, SS3, SS4, the condenser lens composed of the incident side lens 71 and the emission side lens 72 is S1> SS1, S2> SS2, S3 = SS3, S4 <SS4, and The incident light flux is controlled and emitted so that SS1 = SS2 = SS3 = SS4. As a result, the exit side lens 72 emits a parallel light flux having a substantially uniform light flux density regardless of the distance from the optical axis 58.

  This has the following advantages. In general, when a light beam having a non-uniform density is incident on the first lens array plate 35, the size of the illuminant image formed on each lens element of the second lens array plate 36 becomes non-uniform, and a region where the light beam density is high. As the size of the illuminant image increases. When the illuminant becomes large due to high output of the lamp or the like, the illuminant image also increases proportionally, and an illuminant image larger than the aperture of each lens may be formed, resulting in light loss.

  On the other hand, in the present embodiment, since the light flux density of the incident light to the first lens array plate 35 can be made uniform, the size of the illuminant image can be made almost uniform, and the above-described light loss is reduced. it can.

  FIG. 13 schematically shows a state in which the illuminant image of the pupil plane 41 of the projection lens 40 is viewed from the exit side. At the same time, the second lens array plate 36 is shown by dotted lines so that the correspondence between the second lens array plate 36 and each rectangular lens can be understood. In FIG. 13, the horizontal direction on the paper indicates the long axis direction, and the vertical direction on the paper indicates the short axis direction. In the present embodiment, due to the action of the entrance side lens 71 and the exit side lens 72, the two illuminant images 77 and 78 corresponding to the light sources 30 and 31 correspond to the respective rectangular lenses and have substantially the same size over the entire region. Formed with. The pupil plane 41 is a circle 75 having the same size as the circumscribed circle of the effective area of the second lens array plate 36, and captures light from all the light emitter images, thereby preventing light loss.

  As described above, according to the present embodiment, the light from the plurality of light sources 30 and 31 is deflected by the prism array plate 34 and synthesized, so that the light source image formed on the pupil plane 41 of the projection lens 40 is obtained. An illuminating device which is arranged almost symmetrically with respect to the optical axis 58, has good illuminance uniformity and color uniformity on the screen, and has high light utilization efficiency can be configured. Further, by arranging the lenses 71 and 72 for controlling the luminous flux density of the illumination light, the size of the illuminant image on the pupil plane 41 can be made substantially uniform, and even when a lamp having a relatively large illuminant is used, the second is used. Light loss generated on the lens array 36 can be reduced, and an illumination device with high light utilization efficiency can be configured.

(Embodiment 4)
FIG. 14 shows a schematic configuration of the illumination device and the projection display device according to the fourth embodiment of the present invention. Members having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The projection display apparatus according to the present embodiment uses a liquid crystal panel that modulates light using polarized light or scattering as an image forming unit.

  The configuration from the positive lens 44 to the liquid crystal panel 40 is the same as that of the first embodiment shown in FIG. The present embodiment differs from the first embodiment (FIG. 1) in that the illumination device 80 of the present embodiment replaces the first prism array plate 81 and the second prism array plate 82 with the parabolic mirror 32, 33 and the positive lens 44.

  In the illuminating device of the first embodiment (FIG. 1), the ratio of the size of the prism array plate 34 in the prism array direction and the size of the apertures of the parabolic mirrors 32 and 33 deviates the luminous flux by 60 degrees. : 1. In this case, if the openings of the prism array plate 34 and the first and second lens array plates 35 and 36 are to be made small, it is necessary to make the openings of the parabolic mirrors 32 and 33 small, and the paraboloidal surface. The light collection rate from the mirror lamp is reduced.

  Therefore, in the present embodiment, in order to improve the light collection rate, the openings of the parabolic mirrors 32 and 33 and the openings of the prism array plates arranged close to the lens array plates 35 and 36 are equal. The first prism array plate 81 is provided to deflect the light beams from the parabolic mirrors 32 and 33 by 30 degrees and to enter the second prism array plate 82.

  Light emitted from the lamps 30 and 31 is collected by the corresponding parabolic mirrors 32 and 33 and converted into substantially parallel light. Each light beam enters a first prism array plate 81 composed of a plurality of prisms. The prism elements of the first prism array plate 81 are triangular prisms having an apex angle of 90 degrees. The prism elements of the first prism array plate 81 refract the light incident from the parabolic mirrors 32 and 33 without losing it, and deflect the light from each light source by 30 degrees. In order to deviate by 30 degrees, a medium having a refractive index of approximately 1.73 is used. The first prism array plate 81 is arranged so as to be symmetric with respect to the optical axis 58 of the projection lens. In the present embodiment, the first prism array plate 81 on which the light beams from the two paraboloidal mirrors 32 and 33 enter is composed of one, but the two parabolic mirrors 32 and 33 respectively A plurality of first prism array plates corresponding to the luminous flux may be configured.

  The light deflected by the prism elements of the first prism array plate 81 enters the second prism array plate 82. The prism elements of the second prism array plate 82 are triangular prisms having an apex angle of 60 degrees, and the number thereof is ½ of the number of prism elements of the first prism array plate 81. The arrangement pitch of the prism elements of the second prism array plate 82 is approximately twice the arrangement pitch of the prism elements of the first prism array plate 81. The ratio of the size of the opening in the prism arrangement direction of the second prism array plate 82 and the size of the opening of the parabolic mirrors 32 and 33 is 1.15: 1, which is substantially equal. Therefore, even if the second prism array plate 82 and the first and second lens array plates 35 and 36 are made compact, the light collection rate of the light from the lamp of the parabolic mirror can be increased.

  Each prism element of the second prism array plate 82 refracts the first prism array plate 81 from the parabolic mirrors 32 and 33 to totally reflect the incident light and deviates each optical axis by 60 degrees. . The incident light flux is divided into a plurality of parts by the second prism array plate 82, and the split light flux from the parabolic mirror 32 and the split light flux from the parabolic mirror 33 are alternately synthesized. . The alternately synthesized light beams are converged by the positive lens 44 and are made up of a plurality of dichroic mirrors and enter a color wheel 83 that is rotated at high speed by a motor 84.

  The configuration of the color wheel 83 is shown in FIG. Reference numerals 50, 51, and 52 denote red, green, and blue dichroic filters, respectively. The motor 84 is rotated twice while the red, green and blue images for one frame are displayed on the liquid crystal panel 39. Thereby, even when an image moving at a high speed is displayed, deterioration in image quality can be reduced.

  The light incident on the color wheel 117 is separated into red, green, and blue color lights in time series by the red transmissive dichroic filter 50, the green transmissive dichroic filter 51, and the blue transmissive dichroic filter 52. The red, green, and blue color lights are collected by the condenser lens 43, converted into substantially parallel light, and then incident on the first lens array plate 35 including a plurality of lenses. The light beam incident on the first lens array plate 35 is divided into a large number of light beams and converges on a second lens array plate 36 composed of a plurality of lenses.

  The condensing lens 43 has the same configuration as that of the first embodiment, although the size is different, and the operation thereof is also the same. For this reason, the light beam density of the light beam incident on the first lens array plate 35 decreases as the distance from the optical axis vicinity portion increases (see FIG. 3). Thus, as in the first embodiment, when a light beam having a non-uniform density is incident on the first lens array plate 35, the size of the illuminant image formed on each lens element of the second lens array plate 36 is reduced. It becomes non-uniform, and the size of the illuminant image increases as the luminous flux density increases. Therefore, the pupil plane 41 of the projection lens 40 can be reduced in size without increasing the light loss (see FIG. 5).

  The first and second prism array plates 81 and 82 may be manufactured by molding. By using a molded product, a low-cost prism array plate can be configured. In this case, the accuracy of the apex angle of the prism and the accuracy of the flat surface portion are lowered, but the loss is only slightly increased. The second prism array plate 82 may be made of a resin having high heat resistance. If the first and second prism array plates 81 and 82 are made of resin, the cost can be further reduced.

  As described above, according to the present embodiment, the light from the plurality of light sources 30 and 31 is deflected by the second prism array plate 82 and synthesized, so that it is formed on the pupil plane 41 of the projection lens 40. The light source image is arranged almost symmetrically with respect to the optical axis 58, the illumination intensity uniformity and color uniformity on the screen are good, and an illumination device with high light utilization efficiency can be configured. Further, since the first prism array plate 81 for deflecting the light from the parabolic mirrors 32 and 33 by 30 degrees is provided, the openings of the parabolic mirrors 32 and 33 and the second prism array plate 82, the first and The size of the apertures of the second lens array plates 35 and 36 can be made equal, and a small illuminating device with very high light utilization efficiency can be configured.

(Embodiment 5)
FIG. 16 shows a schematic configuration of an illumination device and a projection display device according to a fifth embodiment of the present invention. Members having the same functions as those in the first to fourth embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. The projection display apparatus according to the present embodiment uses a liquid crystal panel that modulates light using polarized light as an image forming unit.

  The configuration from the discharge lamps 30 and 31 to the color wheel 83 is the same as that of the fourth embodiment shown in FIG. The illuminating device 90 of the present embodiment includes an incident side lens 71 and an output side lens 72 similar to those of the third embodiment between the color wheel 83 and the first lens array plate 35, and a second prism array. Between the plate 36 and the field lens 38, a polarization separation prism array 61 as polarization separation means, a half-wave plate 65 as polarization rotation means, and an auxiliary lens 66 are provided as in the second embodiment. ing.

  Light radiated from the lamps 30 and 31 is refracted by the first prism array plate 81, synthesized by the second prism array plate 82, and separated into a single color by the color wheel 83, and then the incident side lens 71 and the emission side. The lens 72 is converted into substantially parallel light having a uniform light flux density (see FIG. 12), and enters the first lens array plate 35. The light incident on the first lens array plate 35 is subjected to the action described in the second embodiment, and after being aligned with polarized light in a specific direction, the liquid crystal panel 39 is uniformly illuminated.

  FIG. 17 schematically shows a state in which the illuminant image of the pupil plane 41 of the projection lens 40 is viewed from the exit side. At the same time, the second lens array plate 36 is shown by dotted lines so that the correspondence between the second lens array plate 36 and each rectangular lens can be understood. On the pupil plane 41, P-polarized light and S-polarized light emitter images are alternately formed as light source images in the arrangement direction of the prism elements of the polarization separation prism array 61 (vertical direction in FIG. 9). Further, the illuminant image is formed with substantially the same size over the entire area of the pupil plane 41. The pupil plane 41 is a circle 75 having the same size as the circumscribed circle of the effective area of the second lens array plate 36, and captures light from all the light emitter images, thereby preventing light loss.

  As described above, according to the present embodiment, the light from the plurality of light sources 30 and 31 is deflected by the second prism array plate 82 and synthesized, so that it is formed on the pupil plane 41 of the projection lens 40. A light source image is arranged substantially symmetrically with respect to the optical axis 58, and an illumination optical device with high illuminance uniformity and color uniformity and high light utilization efficiency can be configured. Further, by arranging the lenses 71 and 72 for controlling the luminous flux density of the illumination light, the size of the illuminant image on the pupil plane 41 can be made substantially uniform, and even when a lamp having a relatively large illuminant is used, the second is used. Light loss generated on the lens array 36 can be reduced, and an illumination device with high light utilization efficiency can be configured. In addition, since the first prism array plate 81 that deviates the light from the parabolic mirrors 32 and 33 by 30 degrees is provided, the openings of the parabolic mirrors 32 and 33, the second prism array plate 82, the first and second The size of the apertures of the second lens array plates 35 and 36 can be made equal, and a compact and very high light utilization efficiency illumination optical device can be constructed. Furthermore, since a polarization conversion optical member that converts natural light into unidirectionally polarized light is disposed, an illumination optical device with very high light utilization efficiency can be configured.

(Embodiment 6)
FIG. 18 shows a schematic configuration of a projection display apparatus according to Embodiment 6 of the present invention. The projection display apparatus according to the present embodiment uses a reflective liquid crystal panel that reflects and modulates light as an image forming unit.

  Reference numeral 37 denotes the illumination device according to the first embodiment, and reference numeral 100 denotes a reflection type light valve (reflection type liquid crystal panel). Members having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  From the condensing lens 43, as in the first embodiment, a light beam having a higher light beam density is emitted closer to the optical axis 58. The first lens array plate 35 is configured by two-dimensionally arranging rectangular lenses similar to the liquid crystal panel 100.

  The liquid crystal panel 100 is an active matrix type liquid crystal panel, and modulates light by controlling a voltage applied to a pixel in accordance with a video signal to form an optical image. While the color wheel 42 makes one rotation, the liquid crystal panel 100 displays red, blue and green images once each.

  The color light reflected from the liquid crystal panel 100 is enlarged and projected on a screen (not shown) by the projection lens 40. The image projected on the screen appears as a full-color image due to the integral effect of the human eye.

  As described above, according to the present embodiment, the illuminating device according to the first embodiment, in which the light from the light sources 30 and 31 is deflected by the prism array plate 34 and combined as an illuminating device using two light sources. Since it is used, the light from the two light sources can be illuminated to the liquid crystal panel very efficiently and uniformly. Therefore, it is possible to construct a projection display device with good illuminance and color uniformity and high light utilization efficiency.

  It can replace with the illuminating device 37 and can also use the illuminating device of Embodiment 2-5.

  In the above-described embodiment, an example in which a liquid crystal panel using polarized light or scattering is used as an image forming unit is shown. However, an optical according to a video signal as a change in diffraction, reflection, or the like such as a digital micromirror device (DMD). Image forming means for forming an image may be used. Further, a rear projection display device may be configured using a transmission screen.

(Embodiment 7)
FIG. 19 shows a schematic configuration of a projection display apparatus according to Embodiment 7 of the present invention. The projection display apparatus according to the present embodiment uses a reflective liquid crystal panel that modulates light using polarized light as an image forming unit.

  90 is a lighting device according to the fifth embodiment, 100 is a reflection type light valve (reflection type liquid crystal panel), 110 is a lamp power source of the lamp 30, 111 is a lamp power source of the lamp 31, and 112 is a lamp based on a clock signal of the liquid crystal panel. A controller 120 for controlling the driving waveforms of the power supplies 110 and 111, 120 is a polarization separation prism. Members having the same functions as those of the fifth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As described in the fifth embodiment, a light beam having a substantially uniform light beam density is emitted from the emission side lens 72 regardless of the distance from the optical axis. The first lens array plate 35 is configured by two-dimensionally arranging rectangular lenses similar to the liquid crystal panel 100.

  Light from the field lens 38 enters the polarization separation prism 120. The polarization separation prism 120 is a prism having a polarization separation film composed of a dielectric multilayer film. The incident angle of the polarization separation film is 45 °, and the P polarization with respect to the polarization separation film surface is transmitted and the S polarization is reflected.

  The reflected S-polarized light enters the reflective liquid crystal panel 100. The reflective liquid crystal panel 100 is an active matrix system, and includes a liquid crystal layer and a reflective film. As the liquid crystal, ferroelectric liquid crystal, homeotropic liquid crystal, HAN mode liquid crystal, or 45 degree twisted nematic liquid crystal is used. In the reflective liquid crystal panel, the birefringence of the liquid crystal changes when a voltage is applied according to the video signal. Incident light to the reflective liquid crystal panel is transmitted through the liquid crystal, reflected by the reflective film, and transmitted through the liquid crystal again, and the polarization state of the light changes from S-polarized light to P-polarized light due to birefringence and is emitted. The P-polarized color light emitted from the reflective liquid crystal panel 100 is transmitted through the polarization separation prism 120 and then enlarged and projected onto a screen (not shown) by the projection lens 40.

  On the other hand, the S-polarized light whose polarization state is not changed by the reflective liquid crystal panel 100 enters the polarization separation prism 120, is reflected by the polarization separation film surface, and returns to the illumination device 90 side. In this manner, an optical image formed as a change in the polarization state of light in the reflective liquid crystal panel 100 is enlarged and projected on a screen (not shown) to form a full-color projection image.

  While the color wheel 83 makes one rotation, the liquid crystal panel 100 displays red, blue and green images once each. The image projected on the screen appears as a full-color image due to the integral effect of the human eye.

  At this time, when an AC lighting lamp is used as the light sources 30 and 31, the lamp is lit with a square wave generated from the lamp power supply, but this drive current always has overshoot and undershoot different from the steady values. When two lamps are used, if the lighting frequencies of the two lamps are different, an unsteady component that is asynchronous with the clock of the image is generated, and it looks as if it is flicker. If the lighting frequencies of both lamps are the same, these non-stationary components are generated at a fixed cycle, and if the lamp lighting cycle is synchronized with the clock of the image, it appears as constant noise. Furthermore, as shown in FIG. 20, by shifting the driving timing of the lamp 30 and the driving timing of the lamp 31 by a quarter cycle, the unsteady component becomes relatively smaller than the steady component, and is less noticeable on the image. In FIG. 20, (A) shows the driving current waveform of the lamp 30, (B) shows the driving current waveform of the lamp 31, and the horizontal axis is the time axis.

  As described above, according to the present embodiment, the illumination device 90 according to the fifth embodiment is used as an illumination device using two light sources, and thus the light from the two light sources is very efficiently and uniformly distributed. The LCD panel can be illuminated. Therefore, it is possible to construct a projection display device with good illuminance and color uniformity and high light utilization efficiency. Furthermore, controlling the lighting cycle and driving timing of the light source leads to an improvement in image quality.

  In addition, it can replace with the illuminating device 90 and can also use the illuminating device of Embodiment 1-4.

  In the above embodiment, an example in which a liquid crystal panel using polarized light is used as the image forming unit has been described. However, a liquid crystal panel using a ferroelectric liquid crystal having a high speed response is particularly preferable. Further, an image forming unit that forms an optical image corresponding to a video signal as a change in diffraction, reflection, or the like such as a digital micromirror device (DMD) may be used. Further, a rear projection display device may be configured using a transmission screen. A transmissive liquid crystal panel may be used.

  The field of application of the present invention is not particularly limited, and can be widely used as a projection display device that projects an optical image on a screen in an enlarged manner.

It is a schematic block diagram of the illuminating device and projection type display apparatus in Embodiment 1 of this invention. It is a block diagram of the color wheel of the illuminating device of FIG. It is a conceptual diagram for demonstrating the light beam control by the condensing lens of the illuminating device of FIG. It is a block diagram of the 1st lens array board of the illuminating device of FIG. It is the schematic diagram which showed the light source image formed in the pupil plane of the projection lens of the projection type display apparatus of FIG. It is a schematic block diagram of the illuminating device and projection type display apparatus in Embodiment 2 of this invention. It is a block diagram of the polarization splitting prism array and the half-wave plate of the illuminating device of FIG. 6, (A) is a front view, (B) is a side view, (C) is a bottom view. It is explanatory drawing for demonstrating the effect | action of the polarization splitting prism array and the half-wave plate of the illuminating device of FIG. It is the schematic diagram which showed the light source image formed in the pupil plane of the projection lens of the projection type display apparatus of FIG. It is a schematic block diagram of the illuminating device and projection type display apparatus in Embodiment 3 of this invention. It is a block diagram of the color wheel of the illuminating device of FIG. It is a conceptual diagram for demonstrating the light beam control by the entrance side lens and exit side lens of the illuminating device of FIG. It is the schematic diagram which showed the light source image formed in the pupil plane of the projection lens of the projection type display apparatus of FIG. It is a schematic block diagram of the illuminating device and projection type display apparatus in Embodiment 4 of this invention. It is a block diagram of the color wheel of the illuminating device of FIG. It is a schematic block diagram of the illuminating device and projection type display apparatus in Embodiment 5 of this invention. It is the schematic diagram which showed the light source image formed in the pupil plane of the projection lens of the projection type display apparatus of FIG. It is a schematic block diagram of the projection type display apparatus in Embodiment 6 of this invention. It is a schematic block diagram of the projection type display apparatus in Embodiment 7 of this invention. It is a drive waveform figure of the lamp | ramp of the illuminating device of the projection type display apparatus of FIG. It is a schematic block diagram of the conventional illuminating device and projection type display apparatus. It is the schematic diagram which showed the light source image formed in the pupil plane of the projection lens of the conventional projection display apparatus.

Explanation of symbols

30, 31 Discharge lamps 32, 33 Parabolic mirror 34 Prism array plate 35 First lens array plate 36 Second lens array plate 37 Illuminator 38 Field lens 39 Liquid crystal panel 40 Projection lens 41 Pupil plane 42 of projection lens Color wheel 43 Condensing lens 44 Positive lens 50 Red transmissive dichroic filter 51 Green transmissive dichroic filter 52 Blue transmissive dichroic filter 53 Visible light transmissive filter 54, 55 Light-emitting body image 56 The circumscribed circle 57 of the effective area of the second lens array plate Virtual circle 58 Optical axis 60 Illumination device 61 Polarization separation prism array 62 Polarization separation prism 63 Polarization separation film 65 Half-wave plate 66 Auxiliary lens 70 Illumination device 71 Incident side lens 72 Emission side lens 73 Color wheel 74 Motor 75 Effective area of second lens array plate Circumscribed circle and Circles 77 and 78 of the same size Light emitter image 80 Illumination device 81 First prism array plate 82 Second prism array plate 83 Color wheel 84 Motor 90 Illumination device 100 Liquid crystal panel 110, 111 Lamp power supply 112 Controller 120 Polarization separation prism 900 Illuminating devices 901, 902 Discharge lamps 903, 904 Parabolic mirror 905 Positive lens 906 Rotating plate 907 Motor 908 Condensing lens 909 First lens array plate 910 Second lens array plate 911 Liquid crystal panel 912 Field lens 913 Projection lens 914 Projection Lens pupil plane 922, 923 Light source image group 924 Light source image

Claims (4)

A plurality of light sources that emit light at substantially the same light emission period and at different light emission timings;
Color separation means for separating light from the light source for each specific wavelength band every time;
One image forming means for forming an optical image in response to a video signal;
Illumination means for condensing light from the color separation means and illuminating the image forming means;
A projection display device comprising: a projection lens that projects an optical image on the image forming unit onto a screen.   The projection display device according to claim 1, wherein the light emission periods of the plurality of light sources are different from each other by approximately ¼ period.   The projection display device according to claim 1, wherein the image forming unit is a transmissive display device.   The projection display device according to claim 1, wherein the image forming unit is a reflective display device.

Images