JP4909703B2 - projector - Google Patents

Description

  The present invention relates to a projector, and more particularly to a projector using an illumination optical system of a single plate type liquid crystal projector.

  Conventionally, as a projector that is a projection display device, a light source is disposed at the incident end of a prismatic light guide member, and a liquid crystal panel that is an image forming element is disposed at the exit end side of the light guide member. A projector having an illumination optical system that directly enters light emitted from an optical member into a liquid crystal panel is known.

  In a projector using a liquid crystal panel as a display element, regardless of whether the light source is a discharge lamp or a light emitting diode, as long as a non-polarized light source is used, either one of the linearly polarized light is used to increase the light use efficiency. The polarization conversion for unifying is performed. In addition, since it is very important to ensure the uniformity of the brightness of the projected image simultaneously with the polarization conversion, it is necessary to achieve both the polarization conversion and the brightness uniformity.

  As a configuration that can achieve both, a configuration using a discharge lamp (white non-polarized light), a fly-eye lens, and a flat PBS (polarized beam splitter) has been established by Seiko Epson, Is recognized as the most advanced technology in LCD projectors.

  The advantage of this configuration is that polarized light with a phase difference plate integrated in the gap by skillfully using the spatial gap created by the light splitting by the fly-eye lens and the collection of the split luminous flux. By arranging the beam splitter array, polarization conversion is performed while suppressing an increase in the beam diameter of the beam supplied from the lamp reflector.

  However, this configuration is not optimal when it is intended to be applied to a micro projector using a light source as a light source. This is based on the premise that a light source discharge lamp having a light emission length of about 1 mm to 1.2 mm is combined with a reflector having a parabolic surface to produce substantially parallel light. This is because, when aiming for a projector that can also be driven by a battery, the optical system becomes large and it is difficult to apply.

  The size of the light emitting part of the light emitting diode, which is a small light source, is usually about 2 mm square or more. If the reflector is combined in the same manner as the discharge lamp, the size of the light source portion reaches several tens of mm, and a small projector cannot be realized. If combined with a reflector having a small aperture, the lamp reflector (light source part) becomes small, but it is very difficult to collimate the light from the light emitting part that is more than twice that of the discharge lamp. Usage efficiency cannot be achieved.

  The use of a rod integrator is a very effective means in terms of improving the uniformity of projection screen brightness. This has long been known in the illumination system of exposure apparatuses. As an application example of a rod integrator to a projector illumination system, it has been put into practical use in a DLP (Digital Light Processing) projector optical system using a white discharge lamp, and is a standard. Furthermore, unlike liquid crystals, unpolarized light is not required at all, so there is no need to perform polarization conversion.

  Several years ago, a reflective polarizing plate was put to practical use by Moxtek. If the reflection type was used and it could be used as an alternative to PBS (polarization beam splitter) instead of just a polarizing plate, a new configuration of polarization conversion could be expected.

  In fact, in the past, a rod mirror was installed in the entrance aperture of the rod integrator, and a quarter wavelength plate and a reflective polarizing plate were provided on the exit side. (Unified) functions are integrated. Foreign manufacturers have also made presentations at international academic conferences related to microdisplays.

  However, a projector that embodies this configuration has not been released by any manufacturer so far. There are two main reasons. One is the presence of a perforated mirror placed on the entrance end face of the rod integrator. This hole restricts the opening of incident light and causes a loss of reflected light from the polarizing plate.

  That is, the convergent light beam from the light source is incident on the perforated mirror, but it is preferable that the hole is as large as possible to allow more light to enter. However, the light reflected by the reflective polarizing plate on the exit end face once returns to the direction of the perforated mirror on the entrance end face. Therefore, when the hole is large, there is a problem that the returned light is not reflected by the mirror part of the perforated mirror and passes through the hole to the light source side and is not used.

  On the other hand, if the hole is made smaller, another problem occurs. Although the reflected light from the reflective polarizing plate that escapes to the light source side is reduced due to the smaller hole, this is also a problem because less light should be incident on the rod integrator first.

  It seems to be necessary to relatively increase the outer shape of the rod integrator, but this must be avoided. In such a case, the light use efficiency is reduced as a result. Since the emitted light in the shape of the exit end face of the rod integrator is expanded to correspond to the display panel, the smaller the exit end face of the rod integrator, the better if the light utilization efficiency is desired.

  More specifically, the size of the exit end face of the rod integrator is usually smaller than the size of the display panel of the DMD (digital micromirror device). The fact that the size of the exit surface of the rod integrator is smaller than that of the DMD requires that an illumination system for enlarging an image corresponding to the DMD display area to form an image.

  During this expansion process, the beam spreading angle when exiting the rod integrator decreases and reaches the DMD. If the divergence angle is reduced, the DMD can be efficiently illuminated and the subsequent lens system can easily pass through, so that high light utilization efficiency can be achieved as a whole.

  Another reason that has not been put into practical use is the polarization conversion process, that is, the polarization disturbance during propagation in the rod integrator. This disturbance occurs particularly in the process in which the polarizing plate reflected light undergoes polarization conversion. Even if it is efficiently separated into linearly polarized light in the reflective polarizing plate, the polarization is disturbed while being reflected many times in the rod integrator. Disturbed polarized light cannot finally pass through the reflective polarizing plate, resulting in light loss.

  Due to the nature of the rod integrator, the greater the internal reflection, the higher the brightness uniformity. However, on the other hand, it is inevitable that the polarization disturbance increases. It is difficult to achieve both uniformity and suppression of polarization disturbance.

  For the above two main reasons, it is considered that a method of using a reflective polarizing plate as an alternative to PBS (polarizing beam splitter) has not been put into practical use. As a matter of course, just because the light source is changed to a light emitting diode (LED), it cannot be improved.

  In recent years, projectors using LEDs as light sources have been disclosed. By using an LED as a light source, a cost reduction can be expected as compared with a projector using a conventional white discharge lamp, and features such as a small size, low power consumption, and a wide color reproduction range can be realized.

  Japanese Unexamined Patent Application Publication No. 2006-106683 discloses a conventional projector using a single DMD element for a display panel and a light emitting diode as a light source. -106682) also discloses a conventional projector using a single DMD element as a display panel and a light emitting diode as a light source.

Non-Patent Document 1 discloses a projector of a conventional example using a light-emitting diode light source and an LCoS element (reflective liquid crystal device) which is a single reflective liquid crystal device as a display element. 2 and Non-Patent Document 3 disclose a portable mini projector using a light-emitting diode light source and three liquid crystal panels.
JP 2006-106683 A JP 2006-106682 A "Single-Panel LCoS Color Projector with LED Light Source" SID 05 DIGEST pp 1698-1701 "A Handheld Mini-Projector Using LED Light Sources" SID 05 DIGEST pp1706-1709 “Compact Panel LED Project Engine Engine for Portable Applications” SID 06 DIGEEST pp2011-2014

  In order to reduce the cost of the projector, it is desirable that the number of parts of the optical engine is small. Therefore, it can be said that a projector using a single display element is more advantageous than a projector using three display elements disclosed in Non-Patent Documents 2 and 3. Further, the small number of parts of the optical system contributes to the miniaturization of the entire projector.

  Therefore, it is preferable to use a single liquid crystal panel rather than using the DMD element disclosed in Patent Documents 1 and 2, which require a configuration of a reflective optical system.

  Further, in order to improve the color reproducibility of the projector and increase the luminance, it is preferable to separately prepare light emitting diodes of light sources of red, blue and green color lights. However, in order to irradiate the light from the light emitting diodes individually provided on a single display panel, the light from each light source is temporarily merged with each other by using a dichroic mirror or a dichroic prism. In addition, it is necessary to irradiate the display panel with light, and a space for arranging these optical components is required.

  Also, when an optical system of a projector is realized using an LED light source for a single liquid crystal panel, the liquid crystal panel must be irradiated with polarized light. Since the light from the LED is non-polarized light, it is necessary to perform polarization conversion.

  Generally, when the display panel is a TN liquid crystal panel, it is necessary to irradiate linearly polarized light. That is, it is necessary to convert and irradiate one of the orthogonally polarized light components of the non-polarized light from the light source so as to be the same as the other polarized light components.

  If this polarization conversion is not performed efficiently, the light utilization efficiency will be reduced. If no polarization conversion is performed, about half of the light will be thrown away. As a countermeasure, for example, in Non-Patent Document 1, a light guide member having a composite parabolic shape called a CPC reflector is disposed immediately after an LED element that is a light source.

  The light from the light source is converted into substantially parallel light using total reflection at the CPC reflector and emitted to illuminate the display panel. For polarization conversion, a quarter-wave plate and a reflective polarizing plate are arranged at the exit of the CPC reflector.

  The linearly polarized light (for example, S-polarized light) reflected by the reflective polarizing plate is returned to the LED as the light source, reflected again on the LED surface, and taken out from the CPC reflector to pass twice through the quarter wavelength plate. Is converted into linearly polarized light (for example, P-polarized light) that can be transmitted through a polarizing plate.

  However, this method cannot achieve high polarization conversion efficiency. The component light reflected by the reflective polarizing plate efficiently returns to the surface of the LED light source. However, since the reflectance of the surface of the LED element which is a semiconductor is only about 17% to 20% at most, the reflection here cannot be expected so much. Since the light loss on the LED surface is large, the efficiency (gain) of polarization conversion is only about 1.2 compared to the case where no reflective polarizing plate is provided.

  Further, when a single-plate projector using a single display panel is used, it is necessary to supply the display panel with a repetition of color light of red → blue → green → red → blue → green →. . If the light source is limited to light-emitting diodes, the optical system is configured by arranging three types of light-emitting diodes of red, blue, and green in order to improve color reproducibility as a projector and achieve high brightness. Good.

  Since it is necessary to irradiate the liquid crystal panel with light from the light emitting diodes of different colors, the illumination lens is made to correspond to each of the light emitting diodes and the light from each rod integrator is irradiated to the liquid crystal panel. It is most desirable to control so that each light emitting diode is turned on in turn. Since it is a single plate type, light emitting diodes of different colors and a plurality of rod integrators are indispensable components in order to improve color reproducibility and achieve high brightness. The next issue is how to change the means of polarization conversion, but we do not want the structure to become large or complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a projector with high light utilization efficiency, in which polarization conversion is performed with high efficiency, while using a rod integrator in the illumination optical system of a single-plate liquid crystal projector.

The projector of the present invention
A projector that projects the formed image by causing the first color light, the second color light, and the third color light from the light source to enter the single image forming element via the light guide member and the illumination lens. A first light guide member provided with a selective reflection light-transmitting film that transmits the first color light and reflects the second color light and the third color light; and an optical axis of the first light guide member. A first light source unit comprising a first light source arranged and emitting a first color light, and an optical axis of the illumination lens as a symmetry axis, the first light guide member and the first light source at a symmetrical position A second light guide member provided with a selective reflection light-transmitting film that is provided and transmits the second color light and the third color light and reflects the first color light; and an optical axis of the second light guide member A second light source that is disposed on the second light source and emits light by selecting the second color light and the third color light, and forms a light source together with the first light source. A reflection type polarizing plate that is provided between the light source unit 2, the illumination lens, and the image forming element, transmits the first polarized light and reflects the second polarized light, and reflects the reflected light from the reflective polarizing plate. A phase difference plate that converts circularly polarized light and converts reflected light from the selective reflection translucent film into first polarized light, and emits light and reflected light from the first light source unit to the reflective polarizing plate, The reflected light from the reflective polarizing plate is emitted to the selective reflection light-transmitting film of the second light source unit, and the outgoing light and reflected light from the second light source unit are emitted to the reflective polarizing plate, And an illumination lens group that emits the reflected light from the light to the selective reflection light-transmitting film of the first light source unit.

  One or more combinations of the first light source unit and the second light source unit combined with the first light source unit are provided, and the optical axis of the first light guide member of the first light source unit forming the set The optical axis of the second light guide member of the second light source unit is arranged on the target with the optical axis of the illumination lens as the symmetry axis, and the optical axes of the plurality of first light guide members, The optical axes of the second light guide members may be arranged on the same plane.

  There are two or more combinations of the first light source unit and the second light source unit, and the second light source is a third light source that emits second color light and a fourth light source that emits third color light. The third light source and the fourth light source may be divided and arranged in the second light source unit so as to have a predetermined number. Further, the first color light may be green, the second color light may be red, and the third color light may be blue. Further, the selective reflection light-transmitting film may be formed on a glass substrate, and the glass substrate may be disposed on either the incident side or the emission side of the light guide member.

  The illumination lens group includes an auxiliary lens for a light source provided on each emission side of the first light guide member and the second light guide member, and light emitted from the auxiliary lens on the first light guide member side. The light is emitted to the reflective polarizing plate, the reflected light from the reflective polarizing plate is emitted to the selective reflection light-transmitting film of the second light guide member via the auxiliary lens on the second light guide member side, and the second The light emitted from the auxiliary lens on the light guide member side is emitted to the reflective polarizing plate, and the reflected light from the reflective polarizing plate is selected via the auxiliary lens of the first light guide member. You may be comprised from the 1st illumination lens and 2nd illumination lens which radiate | emit to a reflective light transmission film.

  The single plate type image forming element may be a single liquid crystal panel, and the first to fourth light sources may be light emitting diodes.

  A reflection mirror that converts the optical axis of the second light guide member in a direction orthogonal to the optical axis of the illumination lens; a second light source on the optical axis of the second light guide member converted by the reflection mirror; A second rod integrator and an auxiliary lens may be provided, and includes a reflection mirror that converts the optical axis of the first light guide member in a direction perpendicular to the optical axis of the illumination lens, and is converted by the reflection mirror. The first light source, the first rod integrator, and the auxiliary lens may be provided on the optical axis of the first light guide member.

  A single plate that makes light from the light source incident on the rod integrator, illuminates the light emitted from the rod integrator at a predetermined magnification by the illumination lens and irradiates a single liquid crystal panel, and enlarges and projects the image on the liquid crystal panel by the projection lens The type liquid crystal projector includes a reflective polarizing plate in the vicinity of the incident side of the liquid crystal panel.

  In addition, at least two rod integrators are provided, and each rod integrator is arranged such that its central axis is parallel to the optical axis of the illumination lens and separated by a predetermined distance. Here, the predetermined distance is that the central axes of the two rod integrators are equidistant from the optical axis of the illumination lens. That is, the two rod integrators are arranged symmetrically with respect to the optical axis of the illumination lens. The optical axis of the illumination lens and the center axis of the display panel may or may not substantially coincide with each other.

  Light sources are respectively arranged in the vicinity of the incident surfaces of the two rod integrators that form a pair. For example, a light source of green color light is disposed on the first rod integrator, and a light source that selects and emits blue and red color light is disposed on the second rod integrator, for example. The two rod integrators are preferably provided with light sources of different colored lights.

  A selective reflection type translucent film having a characteristic of transmitting the color light of the light source arranged on each of the rod integrators and reflecting the light of the color light of the light sources arranged on the other rod integrators is provided on the incident end face or the exit end face of each rod integrator Is provided. That is, if a green light source is arranged in the first rod integrator and red and blue light sources are arranged in the second rod integrator, the incident end face or the emitting end face of the first rod integrator A selective reflection type translucent film that transmits colored light and reflects blue and red colored light is deposited. The incident end face or outgoing end face of the second rod integrator transmits blue and red colored light and reflects green colored light. A selective reflection type translucent film is deposited.

  An auxiliary lens is provided on the exit end face side of each lot integrator. The central axis of this auxiliary lens preferably coincides with the central axis of the rod integrator. A plurality of auxiliary lenses may be provided.

  The green color light (unpolarized light) incident on the first rod integrator is reflected from the inner surface of the rod integrator, and even if there is luminance unevenness in the light source, the luminance is uniformed and emitted from the emission end face. . The emitted light is prevented from spreading by the auxiliary lens and is incident on the illumination lens. The illumination lens enlarges the light to a size corresponding to the display area of the liquid crystal panel and forms an image near the liquid crystal panel.

  This is because the specifications (focal length, material, etc.) of the illumination lens are determined so that the exit end face of the rod integrator and the liquid crystal panel surface are conjugate.

  Of the light (unpolarized light) traveling toward the liquid crystal panel, one linearly polarized light (for example, P-polarized light) is transmitted through a reflective polarizing plate disposed immediately before the liquid crystal panel, and finally illuminates the liquid crystal panel. The light reaches the screen after passing through the projection lens. The reflective polarizing plate is preferably perpendicular to the optical axis of the illumination lens.

  Most of the linearly polarized light reflected by the reflective polarizing plate (for example, S-polarized light) returns in the opposite direction to the path along the illumination lens, but cannot reach the exit surface of the first rod integrator. Instead, the light is condensed and reaches the exit surface of the second rod integrator having a symmetrical relationship.

  A selective reflection light-transmitting film reflecting green color light is deposited on the emission surface, so that most of the light is reflected by the film and passes again through the auxiliary lens and illumination lens toward the liquid crystal panel. To reach the reflective polarizing plate.

  Here, if a phase difference plate, for example, a quarter-wave plate, is disposed between the selective reflection light-transmitting film and the reflective polarizing plate, this light is polarized light that can pass through the reflective polarizing plate, that is, P Most of the polarized light is converted to polarized light.

  In addition, since the light passes through the same illumination lens as the illumination light from the rod integrator, the light that first transmitted through the reflective polarizing plate and the reflected light illuminate the liquid crystal panel with the same imaging magnification. That is, most of the non-polarized light from the light source is polarized and converted to P-polarized light to become illumination light for the liquid crystal panel.

  The second rod integrator is provided with a light source in which, for example, red and blue light sources are packaged. The light (non-polarized light) incident on the second rod integrator from the light source is made uniform by the internal reflection in the rod integrator, and is emitted from the emission end face.

  The operation and traveling path of light after emission are the same as those of the first rod integrator. The difference is that a selective reflection light-transmitting film having a characteristic of reflecting red and blue color light is deposited on the emission end face of the first rod integrator.

  Of the non-polarized light emitted from the light source in this way, the light reflected from the reflective polarizing plate is also used for illumination as light that can be polarized again and transmitted through the reflective polarizing plate. By combining the light directly transmitted through the reflective polarizing plate, both high polarization conversion efficiency and light utilization efficiency can be achieved.

  Further, this configuration eliminates the need for an optical element for synthesizing the optical paths of the different color lights, so that reduction in size and cost can be promoted, and a small and bright projector with high light utilization efficiency can be realized.

  If each light source is turned on sequentially, that is, the green light emitting diode arranged in the first rod integrator is turned on first, and after turning it off, the red light emitting diode arranged in the second rod integrator is turned on, By repeating the process of turning on the blue light emitting diode arranged in the second rod integrator after turning it off, the green, red, and blue illumination lights can be sequentially supplied to the liquid crystal panel in a time-sharing manner. In addition, color display can be easily performed by driving the liquid crystal panel in synchronization with the change of the color light.

  As described above, in the projector of the present invention, out of the non-polarized light from the light source, first, P-polarized light that has passed through the reflective polarizing plate is used as illumination light for the liquid crystal panel, and reflected by the reflective polarizing plate. The component light is once condensed at a position different from that of the original light source, and converted into polarized light that can pass through the reflective polarizing plate as a secondary light source, that is, P Polarized light is converted into polarized light and used as illumination light for a liquid crystal panel. In particular, the component light reflected from the reflective polarizing plate is reflected without returning to the light source, so that light loss during the polarization conversion process hardly occurs and very high polarization conversion efficiency can be achieved. As an effect, the light utilization efficiency is increased.

  Furthermore, in the configuration of the present invention, the light path where another light source is provided is skillfully used in the process of reusing light reflected from the reflective polarizing plate, and between the light source and the display panel. In addition, there is an effect that miniaturization can be promoted by not requiring an optical component for merging light paths of different colors.

  Furthermore, since the number of light sources can be easily increased and high polarization conversion efficiency can be maintained, there is an effect that it is possible to provide a high-brightness projector with high light use efficiency and good color reproducibility.

  The projector according to the present invention has a configuration using a rod integrator that is a light guide member in an illumination optical system of a single-plate liquid crystal projector. A high projector can be provided.

  Next, the configuration and function of an embodiment of the projector of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a projector including the optical system according to the first embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of the optical system according to the first embodiment of the present invention.

  The projector 1 of the present invention includes an optical system 2 having an illumination optical system 10, an image forming element including a liquid crystal panel 53, and a projection lens 55.

  The illumination optical system 10 includes a first light source 11 that emits first color light, a second light source 12 that selectively emits second color light and third color light, and a first rod integrator 21. The second rod integrator 22 includes a plurality of auxiliary lenses 31 to 34 and two illumination lenses 41 and 42. Further, selective reflection light-transmitting films 23 and 24 that are the characteristics of the present invention are provided on the exit surface or the incident surface of the first rod integrator 21 and the second rod integrator 22. Here, the description will be made assuming that the light exit surface is provided.

  On the optical axis 71 of the first light guide member, the first light source 11 is arranged to be on the incident surface side of the first rod integrator 21, and on the optical axis 72 of the second light guide member, The two light sources 12 are arranged on the incident surface side of the second rod integrator 22.

  The optical axis 71 of the first light guide member and the optical axis 72 of the second light guide member are provided symmetrically with the illumination lens optical axis 73 as the axis of symmetry, and the first light source 11 and the first rod. The integrator 21, the second light source 12, and the second rod integrator 22 are also arranged at symmetrical positions.

  Here, in order to reduce the size of the illumination optical system 10, the light sources 11 and 12 will be described as using light emitting diodes. However, the light source is not limited to a light emitting diode, and the illumination optical system of the present application can be applied to a light source that can be used for image formation, for example, a solid light source such as an organic EL.

  The light emitting diode is a light source that emits a single color light, and if red, blue, and green light emitting diodes are used, there is an advantage that a wide color reproduction can be realized as a projector.

  Here, a light emitting diode of green color light is used for the first light source 11. In the embodiment, four 1 mm square light emitting elements are used as the size of the light emitting elements, and these are arranged on the same plane at a minute interval, and as a whole, have a light emitting area of about 2 mm square. A light source is formed.

  For the second light source 12, light emitting diodes of blue and red color lights are used. In the embodiment, two red light-emitting elements each having a size of about 1 mm square, two blue light-emitting elements are provided, and a total of four light-emitting elements are arranged on the same plane at minute intervals. A solid light source having a light emitting area of 2 mm square is formed. The red light emitting element and the blue light emitting element can be driven independently.

  The size of the light emitting portion of the light emitting diode as a light source is not limited to about 2 mm square as in the embodiment. As the size of the light emitting element increases, the amount of emitted light increases accordingly, but it also increases the power consumption necessary for lighting, and therefore needs to be determined in consideration of product planning such as the target performance of the product.

  The color light of the first light source and the color light of the second light source are not limited to green, and blue and red, respectively, but the two rod integrators 21 and 22 are provided with light sources of different color lights. It is desirable.

  The rod integrators 21 and 22 may be made of optical glass or resin. In the embodiment, the size of the light source 11 or 12 was used with a size of 2 mm × 2.7 mm in length × width and 15 mm in length corresponding to the size of the light sources 11 and 12 described above.

  In the present embodiment, the light guide member is described as a rod integrator, but the present invention is not limited to this, and for example, a light tunnel may be used. Further, the entrance end face and the exit end face may have different sizes. However, the size of the incident end face is preferably larger than that of the light emitting element.

  Further, the shape of the emission end face is preferably similar to the aspect ratio of the display panel 53. Furthermore, the longer the length of the rod integrator, the higher the luminance unevenness reduction effect of the light source, but the length is not limited to 15 mm.

  The distance between the light source and the rod integrator is preferably as close as possible. Because light emitted from the light emitting diode of the light source is emitted in all directions, the light incident on the rod integrator decreases as the distance between the rod integrator and the light source increases, and eventually reaches the screen. This is because the amount of light is reduced.

  Selective reflection light-transmitting films 23 and 24 having characteristics of transmitting color light of their own light source and reflecting other color light are deposited on the incident end face or exit end face of each rod integrator 21 and 22.

  FIG. 3 is a graph showing the reflection characteristics of the selective reflection light-transmitting film. (A) shows the characteristics of the first selective reflection light-transmitting film that reflects red and blue, and (b) shows the first characteristic that reflects green. FIG. 4 is a perspective view showing a rod integrator and a glass substrate on which the selective reflection light-transmitting film is formed.

  Here, the green first light source 11 is arranged on the first rod integrator 21, and the red and blue second light sources 12 are arranged on the second rod integrator 22.

  Therefore, the incident end face or the exit end face of the first rod integrator 21 reflects the blue and red color lights of the second light source 12 as shown in FIG. A first selective reflection transparent film 23 having a characteristic of transmitting green color light is deposited. Further, the incident end face or the exit end face of the second rod integrator 22 reflects the green color light of the first light source 11 as shown in FIG. A second selective reflection light-transmitting film 24 having a characteristic of transmitting red color light is deposited.

  A thin film having such characteristics can be obtained by vacuum deposition of a dielectric multilayer film and can be formed by a known technique. The selective reflection light-transmitting film is not necessarily limited to the formation of a thin film on the incident or exit end face of the rod integrator. For example, as shown in FIG. 4, a selective reflection light-transmitting film 83 may be formed on a glass substrate 82 or the like and disposed adjacent to the incident or exit end face of the rod integrator 81.

  Here, the selective reflection light-transmitting films 23 and 24 are formed on the exit end faces of the rod integrators 21 and 22, but may be formed on the entrance end face.

  A first auxiliary lens 31 and a second auxiliary lens 32 are provided on the emission end face side of the first lot integrator 21, and a third auxiliary lens 33 and a second auxiliary lens 32 are provided on the emission end face side of the second lot integrator 22. A fourth auxiliary lens 34 is provided.

  The central axes of these auxiliary lenses 31 and 32 coincide with the central axis of the first rod integrator 21, and the central axes of the auxiliary lenses 33 and 34 coincide with the central axis of the second rod integrator 22. Is preferred. The central axis of the rod integrator means a straight line connecting the center of the incident end face and the center of the exit end face.

  A lens having a positive refractive power is used as the auxiliary lens. These auxiliary lenses are not necessarily required, but it is preferable to reduce the size of the optical system. This is because the light beam emitted from the rod integrator is a light beam that has spread considerably, and the size of the illumination lens can be suppressed by suppressing the spread by the auxiliary lens.

  The auxiliary lens is not limited to a two-lens configuration. Further, the outer shape of the auxiliary lens is not limited to a circle. This is because light emitted from a rod integrator having a rectangular emission surface is not circular immediately after that. It may be determined in consideration of the miniaturization of the lens and the manufacturing cost. For example, it is possible to obtain them by integral molding using rectangular auxiliary lenses.

  Here, the first rod integrator 21 and the second rod integrator 22, the first auxiliary lens 31 and the third auxiliary lens 33, and the second auxiliary lens 32 and the fourth auxiliary lens 34 are optically identical. Specifications are used.

  The same specification means that the focal length, the refractive index, and the physical shape are the same. By using parts with the same specifications, parts can be shared, and the cost merit of mass production can be derived.

  Between the second auxiliary lens 32, the fourth auxiliary lens 34, and the liquid crystal panel 53, a first illumination lens 41 and a second illumination lens 42 are arranged.

  The light of green color light (unpolarized light) incident on the first rod integrator 21 is made uniform by the internal reflection in the first rod integrator 21 even if the light source has uneven luminance. The light is emitted from the emission end face.

  The light emitted from the first rod integrator 21 is prevented from spreading by the first auxiliary lens 31 and the second auxiliary lens 32, enters the first illumination lens 41, and the first illumination lens 41. The second illumination lens 42 enlarges the image to a size corresponding to the display area of the liquid crystal panel 53 and forms an image near the liquid crystal panel 53.

  In addition, the light emitted from the second light source 12 is also prevented from spreading by the third auxiliary lens 33 and the fourth auxiliary lens 34, enters the first illumination lens 41, and the first illumination lens 41 and the second illumination lens 42 are enlarged to a size corresponding to the display area of the liquid crystal panel 53 and imaged in the vicinity of the liquid crystal panel 53.

  This is because the specifications (focal length, shape material, etc.) of the illumination lens are determined so that the exit surface of the rod integrator and the liquid crystal panel surface are conjugate. Although it is desirable that the illumination lens and the central axis of the display panel substantially coincide with each other, they do not have to coincide with each other.

  The first illumination lens 41 and the second illumination lens 42 image the illumination information of the exit surfaces of the first rod integrator 21 and the second rod integrator 22 on the entrance surface of the liquid crystal panel 53. The arrangement position and focal length are determined. Although the two-sheet configuration is used here, it is not necessarily limited to the two-sheet configuration.

  Blue and red light (non-polarized light) incident on the second rod integrator 22 also forms an image in the vicinity of the liquid crystal panel 53 through a similar path.

  The image forming element includes a liquid crystal panel 53, a reflective polarizing plate 51, a quarter wavelength plate 52, and a polarizing plate 54.

  A reflective polarizing plate 51 is disposed immediately before the liquid crystal panel 53. The reflective polarizing plate 51 is a polarizer. The reflective polarizing plate 51 has a characteristic of transmitting one linearly polarized light component of the linearly polarized light components orthogonal to the non-polarized light incident from the second illumination lens 42 and reflecting the other. Is used.

  Such a reflective polarizing plate 51 can be manufactured by a well-known technique and can be obtained by a commercial route. FIG. 5 is a schematic side view of a reflective polarizing plate. The reflective polarizing plate 51 has a structure in which a quarter-wave plate 52 is bonded and integrated on the incident side of the reflective polarizing plate 51.

  The incident non-polarized light 91 is separated into transmitted light 92 (P-polarized light, abbreviated as first polarization here) and reflected light 93 (abbreviated as second polarization here). The second polarized light is S-polarized light when reflected by the reflective polarizing plate 51, but is circularly polarized light because it has passed through the quarter-wave plate 52. On the emission side of the liquid crystal panel 53, a polarizing plate 54 is provided as an analyzer.

  In the embodiment, as the liquid crystal panel 53, a transmissive diagonal size having a size of 0.5 type was used. Since the liquid crystal panel 53 is composed of a single-plate projector, it is preferable that the liquid crystal response speed be as fast as possible.

  LCoS, DMD, or the like can be used as the display panel, but in this case, an optical element for making the optical path a reflection optical path is added. In order to reduce the size of the entire apparatus, it is preferable to use a single transmission type liquid crystal.

  Of the light (unpolarized light) emitted from the first rod integrator 21 and directed to the liquid crystal panel 53, one of the first polarized light, linearly polarized light (for example, P-polarized light) is disposed immediately before the liquid crystal panel 53. Then, the light passes through the reflective polarizing plate 51 and passes through the projection lens 55 as illumination light of the liquid crystal panel 53 and finally reaches a projection surface (not shown). Here, the reflective polarizing plate 51 is preferably perpendicular to the optical axis 73 of the illumination lens.

  Most of the linearly polarized light (for example, S-polarized light) that is the second polarized light reflected by the reflective polarizing plate 51 passes through the quarter-wave plate 52 and becomes circularly polarized light. Through the illumination lens 41 and return in the opposite direction to the route that has been taken.

  However, the light beam emitted from the first rod integrator 21 does not reach the emission surface of the first rod integrator 21, and passes through the fourth auxiliary lens 34 and the third auxiliary lens 33 and passes through the illumination lens. The light is condensed and reaches the exit surface of the second rod integrator 22 having a symmetrical relationship with the optical axis 73 as the symmetry axis.

  Here, since the second selective reflection transparent film 24 having the characteristic of reflecting the green color light is deposited on the emission end face of the second rod integrator 22, most of the incident light is second selective reflection transparent. The light is reflected by the optical film 24, passes again through the auxiliary lenses 33 and 34, and the illumination lenses 41 and 42 toward the liquid crystal panel 53, and reaches the reflective polarizing plate 51.

  Since a retardation plate, for example, a quarter-wave plate 52 is disposed between the optical path between the second selective reflection light-transmitting film 24 and the reflective polarizing plate 51, the circularly polarized light passes through the reflective polarizing plate 51. Most of the light is converted into polarized light that can be transmitted, that is, P-polarized light.

  In addition, since it passes through the illumination lenses 41 and 42 common to the illumination light from the second rod integrator 22, both the light initially transmitted through the reflective polarizing plate 51 and the reflected light are liquid crystal with the same imaging magnification. The panel 53 will be illuminated.

  That is, most of the non-polarized light emitted from the first light source 11 is finally converted into P-polarized light and becomes illumination light for the liquid crystal panel 53.

  On the other hand, for example, red or blue light (unpolarized light) incident on the second rod integrator 22 from the second light source 12 in which red and blue light emitting diodes are packaged in one package is generated in the second rod integrator 22. The brightness is made uniform by the internal reflection of the light and emitted from the emission end face. Since the behavior and traveling path of the light after emission are almost the same as those in the case of the first rod integrator 21, detailed description thereof is omitted.

  The difference is that a first selective reflection transparent film 23 having a characteristic of transmitting green light and reflecting red and blue color lights is deposited on the emission end face of the first rod integrator 21.

  In this way, most of the component light reflected from the reflective polarizing plate out of the non-polarized light emitted from the light source is converted into linearly polarized light that can be transmitted through the polarizing plate and can be used as illumination light. It is possible to illuminate the liquid crystal panel while achieving both light utilization efficiency.

  Furthermore, since an optical element for synthesizing optical paths of different color lights is not required, the illumination optical system can be reduced in size and cost. Therefore, a small and bright projector with high light utilization efficiency can be realized.

  If the light-emitting diodes of the respective light sources are sequentially turned on, that is, the green light-emitting diodes arranged in the first rod integrator 21 are first turned on, then turned off, and then the red arranged in the second rod integrator 22 The light emitting diode is turned on, and the blue light emitting diode arranged in the same second rod integrator 22 is turned on after the light emitting diode is turned off. Since green, red, and blue illumination lights can be sequentially supplied, color display can be easily performed by driving the liquid crystal panel 53 in synchronism with changes in the color lights.

  The projection lens 55 is composed of a plurality of lenses for projecting an image formed on the liquid crystal panel 22 onto the projection surface. In this embodiment, since a single liquid crystal display panel is used, the back focus of the projection lens can be shortened, and the entire optical system of the projector can be easily downsized.

  Next, the operation of the optical system of the projector according to the present embodiment will be described with reference to the drawings. FIG. 6 is a schematic configuration diagram for explaining the operation of the optical system of the projector according to the first embodiment of the present invention, and FIG. 7 is the reflection of the optical system of the projector according to the first embodiment of the present invention. It is a typical block diagram for demonstrating operation | movement of the light beam reflected by the type | mold polarizing plate. In FIG. 7, the display of the light flux after the reflective polarizing plate is omitted.

  Referring to FIG. 6, unpolarized light from the first light source 11 that emits green color light first enters the incident end face of the first rod integrator 21. Since the light source is a light emitting diode, the light emitted from it is unpolarized light.

  The non-polarized light that has entered the first rod integrator 21 reaches the emission end face after the luminance unevenness of the light source is uniformly converted by numerous total reflections on the wall surface of the first rod integrator 21.

  Since the first selective reflection light-transmitting film 23 having characteristics of transmitting green color light and reflecting blue and red color light is formed on the emission end face, most of the green color light reaching the emission end face is formed. The light is emitted from the emission end face without loss.

  The first auxiliary lens 31 and the second auxiliary lens 32 having a positive refractive power are disposed immediately after the emission end face, and the light emitted from the first lot integrator 21 is supplemented by the auxiliary lens 31. Diffusion is suppressed by the lenses 31 and 32 and enters the first illumination lens 41.

  Thereafter, the image display area of the liquid crystal panel 53 is illuminated via the first illumination lens 41 and the second illumination lens 42.

  Since the exit end face of the rod integrator 21 is rectangular and has a similar shape to the image display area of the liquid crystal panel 53, the illumination lenses 41 and 42 are arranged so that the exit end face and the image display area of the liquid crystal display panel are substantially conjugated. (The mutual positional relationship and the focal length of the lens, etc.) are determined.

  An incident light beam 61 in FIG. 6 indicates a conjugate relationship between the exit end face of the rod integrator 21 and the liquid crystal panel 53.

  A reflective polarizing plate 51 is provided immediately before the liquid crystal display panel 53, and P-polarized light, which is the first polarized light, for example, out of non-polarized, linearly polarized light components reaching the liquid crystal panel 53 is reflected. 51 is transmitted and reaches the liquid crystal panel 53. This light becomes illumination light for the liquid crystal panel.

  In addition, although the quarter wavelength plate 52 is bonded to the light source side of the reflective polarizing plate 51, the non-polarized light remains unpolarized even if it passes through the quarter wavelength plate 52. Most of the other polarized light component, for example, S-polarized light as the second polarized light is reflected. The distance between the reflective polarizing plate 51 and the liquid crystal panel 53 is preferably as close as possible.

  The light that has contributed to the illumination of the liquid crystal panel 53 passes through the liquid crystal panel 53 and then enlarges and projects the image of the liquid crystal panel 53 on a projection surface (not shown) via the polarizing plate 54 and the projection lens 55 that are analyzers.

  The operation of S-polarized light that is the second polarized light reflected by the reflective polarizing plate 51 will be described with reference to FIG. Of the unpolarized incident light beam 61 that is emitted from the first rod integrator 21 and reaches the reflective polarizing plate 51, the reflected S-polarized light is bonded to the light source side of the reflective polarizing plate 1 1 The light is immediately converted into circularly polarized light by the / 4 wavelength plate 52 and travels in the reverse direction through the second illumination lens 42 and the first illumination lens 41. That is, the first reflected light beam 63 and the second reflected light beam 64.

  These lights now pass through the second illumination lens 42, the first illumination lens 41, the fourth auxiliary lens 34, and the third auxiliary lens 33 to the emission end face of the second rod integrator 22. Condensate.

  As shown in FIG. 2, the optical axis 71 of the first light guide member and the optical axis 72 of the second light guide member are T = T ′ with respect to the optical axis 73 (center axis) of the illumination lens. Thus, the specifications of the illumination lenses 41 and 42 are arranged so as to be symmetric with respect to the optical axis 73 of the illumination lens as the symmetry axis, and the emission end face and the image display area of the liquid crystal display panel are substantially in a conjugate relationship. This is because it is set.

  On the emission end face of the second rod integrator 22, a second selective reflection light-transmitting film 24 having the characteristics of reflecting green color light and transmitting red and blue color light is formed. Therefore, most of the green color light (circularly polarized light) condensed on the exit surface of the second rod integrator 22 is reflected by the second selective reflection light-transmitting film 24 on the exit surface, and the direction of the liquid crystal panel 53 again. Into a first reflected light beam 63 and a second reflected light beam 64 that travel toward. This can be regarded as equivalent to the appearance of the secondary light source of green color light on the exit end face of the second rod integrator 22.

  The first reflected light beam 63 and the second reflected light beam 64 are given a predetermined magnification by the third auxiliary lens 33, the fourth auxiliary lens 34, the first illumination lens 41, and the second illumination lens 42, that is, It is enlarged to a size corresponding to the display area of the liquid crystal display panel 53 and reaches the reflective polarizing plate 51 immediately before the liquid crystal panel.

  This is also because the optical axis 71 of the first light guide member and the optical axis 72 of the second light guide member are T = T ′ with respect to the optical axis 73 (center axis) of the illumination lens. This is because the optical axes 73 are arranged symmetrically with respect to the symmetry axis, and the specifications of the auxiliary lenses corresponding to the first rod integrator 21 and the second rod integrator 22 are the same.

  Here, as described above, the quarter-wave plate 52 is bonded to the reflective polarizing plate 51, and the light beam that has passed through the quarter-wave plate 52 immediately changes from circularly polarized light to P-polarized light. Polarized light is converted. In other words, this polarization conversion changes the light into a polarized light component that can be transmitted through the reflective polarizing plate 51.

  This light is used as illumination light for the liquid crystal panel 53 to enlarge and project an image of the liquid crystal panel 53 on a projection surface (not shown) via the polarizing plate 54 and the projection lens 55.

  In this way, most of the non-polarized light from the green light-emitting diode is illuminated by the liquid crystal panel 53 through the process of polarization separation at the reflective polarizing plate 51 and polarization conversion at the quarter-wave plate 52. Therefore, very high light utilization efficiency can be obtained. In addition, the light after polarization separation is once condensed, and most of the light is converted again into a polarized light component that can be transmitted through the reflective polarizing plate 51, so that very high polarization conversion efficiency can be achieved.

  Next, the operation of the light from the red and blue light emitting diodes of the second light source 12 disposed on the incident end face of the second rod integrator 22 will be described.

  The operation is almost the same as the operation of green light from the first light source disposed in the first rod integrator 21. The difference is that when the light is reflected by the reflective polarizing plate 51 and returns to the exit end face of the first rod integrator 21, the exit end face has a characteristic of reflecting red and blue color light. That is, the optical film 23 is formed.

  That is, red or blue light (unpolarized light) emitted from the second rod integrator 22 is firstly converted into the third auxiliary lens 33, the fourth auxiliary lens 34, the first illumination lens 41, and the second light. The illumination lens 42 is magnified by a predetermined magnification and reaches the reflective polarizing plate 51 immediately before the liquid crystal panel 53. Here, the P-polarized light that is the first polarized light passes through the reflective polarizing plate 51 and reaches the liquid crystal panel 53, and the S-polarized light component reflected by the reflective polarizing plate 51 is reflected by the reflective polarizing plate 51. The light passes through the quarter-wave plate 52 bonded to the polarizing plate 51, becomes circularly polarized light, and travels in the opposite direction, that is, toward the light source.

  The light travels through the second illumination lens 42, the first illumination lens 41, the second auxiliary lens 32, and the first auxiliary lens 31, and then is collected on the emission end face of the first rod integrator 21.

  Then, the incident red and blue color lights (circularly polarized light) are reflected by the second selective reflection light-transmitting film 24 having the characteristics of reflecting the red and blue color lights formed on the emission end face and transmitting the green color lights. Most of the light is reflected on the light exit surface, and the reflected light beam travels in the direction of the liquid crystal panel 53 again. This can be regarded as equivalent to a secondary light source of red or blue color light appearing on the exit end face of the first rod integrator 21.

  After the red or blue color light whose path has been changed to the liquid crystal panel again proceeds in the order of the first auxiliary lens 31, the second auxiliary lens 32, the first illumination lens 41, and the second illumination lens 42. The light reaches the quarter-wave plate 52 bonded to the reflective polarizing plate 51, where the polarization conversion from the circularly polarized light to the P-polarized light is performed, and the light that can be transmitted through the reflective polarizing plate 51. This contributes to the illumination of the liquid crystal panel 53. As in the case of green color light, high polarization conversion efficiency and high light utilization efficiency can be obtained.

  FIG. 8 shows the light transmitted through the reflection type polarizing plate among the light beams emitted from the first rod integrator and the second rod integrator, and reflected by the reflection type polarizing plate, and the second rod integrator and the first rod. FIG. 5 is an optical path diagram depicting both light that has been reflected back to the integrator, reflected again, reached the reflective polarizing plate, and then polarized and reached the liquid crystal panel.

  In addition, although the example in which the selective reflection light-transmitting film is formed on each of the emission end faces of the first and second rod integrators has been described, the formation location of the selective reflection light-transmitting film is limited to the emission end face of the rod integrator. In addition, the same operation and effect can be realized even if it is formed on the incident end face. That is, a selective reflection light-transmitting film having a characteristic of transmitting green light to the incident end face of the first rod integrator and reflecting red and blue light is formed, and red and blue are formed on the incident end face of the second rod integrator. A selective reflection light-transmitting film having a characteristic of transmitting light and reflecting green light may be formed.

  This is because the light returning from the reflection type polarizing plate and condensed on the exit end face of each rod integrator enters the rod integrator from there and reaches the entrance end face of the rod integrator while being reflected. In addition, while traveling through the rod integrator, the reflection on the wall of the rod integrator is totally reflected, so that almost no light loss occurs. Therefore, the same effect can be obtained regardless of whether the selective reflection light-transmitting film is on the entrance end face or the exit end face of the rod integrator.

  Next, a second embodiment of the projector of the present invention will be described with reference to the drawings. FIG. 9 is a schematic perspective view of the optical system of the projector according to the second embodiment, FIG. 10 is a schematic top view of the optical system of the projector according to the second embodiment, and FIG. FIG. 12 is a schematic side view of the optical system of the projector according to the embodiment, and FIG. 12 is a perspective view showing a light source, a rod integrator, and an auxiliary lens according to the second embodiment.

  It is easy to increase the number of light sources to increase the brightness of the projector. If the number of light sources is increased, higher brightness can be expected.

  In the first embodiment, as the light source, one light emitting element in which a light emitting diode of green color light and a light emitting diode of red and blue color light are packaged is used. However, for example, as shown in the perspective view of FIG. 9, a configuration including six light sources may be employed. If the number of light sources is increased, higher brightness can be expected.

  As shown in FIG. 12, in the vicinity of the light source, among the six light sources, three first light sources 111 having green light emitting diodes are provided, and a light emitting element in which red and blue light emitting diodes are packaged is provided. In addition, three second light sources 112 are provided.

Here, a plurality of combinations of a first light source unit made up of the first light source 111 and the first rod integrator 121 and a second light source unit made up of the second light source 112 and the second rod integrator 122 are provided. The optical axis of the first light guide member of each pair of the first light source units and the optical axis of the second light guide member of the second light source unit are symmetrical with respect to the illumination lens optical axis 73. And the optical axes of the plurality of first light guide members and the optical axes of the plurality of second light guide members are respectively disposed on the same plane.
That is, in FIG. 12, the first light source 111a and the second light source 112c make one set, the first light source 111b and the second light source 112b make one set, and the first light source 111c and the second light source 112a. One set.

  For example, the reflected light from the reflective polarizing plate 51 of the light emitted from the first light source 111a is incident on the light output end of the second rod integrator 122c of the second light source 112c, and the light emitted from the second light source 112c is reflected. The reflected light from the mold polarizing plate 51 enters the emission end of the first rod integrator 121a of the first light source 111a.

  As shown in the top view showing the YZ plane in FIG. 10, the three second light sources 112a, 112b, and 112c are light sources each including a light emitting diode in which red and blue light emitting elements are packaged. The light emitting surfaces of the three second light sources 112 are provided close to the incident surfaces of the three second rod integrators 122a, 122b, and 122c. Third auxiliary lenses 133a, 133b, and 133c are provided in the vicinity of the exit surfaces of the three second rod integrators 122, respectively.

  At the emission ends of the three second rod integrators 122, a second selective reflection transmission characteristic of reflecting the green color light of the first light source 111 and transmitting the blue and red color lights of the second light source 112. An optical film 124 is deposited.

  On the lower side of each of the second light source, the second rod integrator, and the third auxiliary lens in FIG. 10, as shown in part in FIG. 11, first light sources 111 a, 111 b, not shown, 111c, first rod integrators 121a, 121b, and 121c, and first auxiliary lenses 131a, 131b, and 131c are provided.

  The first end surface of the three first rod integrators 121 reflects the blue and red color light of the second light source 112 and transmits the green color light of the first light source 111. An optical film 123 is deposited.

  The second auxiliary lenses 132a, 132b, 132c and the fourth auxiliary lenses 134a, 134b, 134c are provided on the emission side of the three first auxiliary lenses 131 and the three third auxiliary lenses 133, respectively. An integrated second auxiliary lens group 135 is provided.

  The light emitted from the second auxiliary lens group 135 enters the first illumination lens 41. Since the configuration and operation after the first illumination lens 41 are the same as those in the first embodiment, the same reference numerals are given and description thereof is omitted.

  Even if the number of light sources increases, the operation of the light emitted from each light source is made the same as in the first embodiment by making the design specifications of the first illumination lens 41 and the second illumination lens 42 correspond. High polarization conversion efficiency is maintained, and extremely high luminance can be achieved in response to the increase in the number of light sources. Here, three light sources are used, but the number of light sources is not limited to three.

  Next, a third embodiment of the projector of the present invention will be described with reference to the drawings. FIG. 13 is a perspective view showing a light source, a rod integrator, and an auxiliary lens according to the third embodiment.

  The third embodiment is an application example of the second embodiment. Since the number of light sources is increased, a monochromatic light emitting diode is used as the light source. In the first and second embodiments, a light source in which blue and red light emitting diodes are packaged is used. In the third embodiment, only a red light emitting diode and a blue light emitting diode are packaged in one package. A light source unit was configured using the converted light source.

  In the arrangement shown in FIG. 13, a first light source 211 made of a green light emitting diode, a third light source 213 made of a red light emitting diode, and a fourth light source 214 made of a blue light emitting diode are used. You can also.

  In the example of FIG. 13, three first light sources 211 made of green light emitting diodes are arranged in the lower stage, two third light sources 213 made of red light emitting diodes, and a fourth light source made of blue light emitting diodes. A total of three light sources 214 and one light source 214 are arranged in the upper stage. What kind of combination should be determined may be appropriately determined according to the light output of the light emitting diode to be used.

  In the case of this combination, the selective reflection light-transmitting film provided in the rod integrator may be the same as that in the first embodiment.

  Next, a fourth embodiment of the projector of the invention will be described with reference to the drawings. FIG. 14 is a schematic configuration diagram of the optical system of the fourth embodiment, and FIG. 15 shows the operation of the light beam reflected by the reflective polarizing plate of the projector optical system of the fourth embodiment of the invention. It is a typical block diagram for demonstrating.

  In the fourth embodiment, as shown in FIG. 14, the first light guide member of the first light source 311, the first rod integrator 321, the first auxiliary lens 331, and the second auxiliary lens 332 is provided. The optical axis 371 and the second light source 312, the second rod integrator 322, the third auxiliary lens 333, and the optical axis 72 of the second light guide member of the fourth auxiliary lens 334 are arranged so as to be orthogonal to each other. Has been.

  Therefore, a reflection mirror 341 for bending the optical axis 72 of the second light guide member at a right angle is provided. The illumination lens optical axis 73, the optical axis 371 of the first light guide member, and the optical axis 372a of the second light guide member are consequently parallel, and the illumination lens optical axis 73 and the distance T, and T ′. Just away. It is preferable that T = T ′.

  The description of the operation is omitted. This is because it is obvious that the effects described in the first embodiment can be obtained even with such an arrangement. FIG. 15 shows an optical path diagram according to this configuration. In the optical path diagram, light rays from the rod integrator to the reflective polarizing plate are drawn, and drawing of light rays after the polarizing plate is omitted.

  According to this arrangement, the first light source 311, the first rod integrator 321, the first auxiliary lens 331, and the second auxiliary lens 332, the second light source 312, the second rod integrator 322, the third The auxiliary lens 333 and the fourth auxiliary lens 334 need not be arranged in parallel. Therefore, when the entire optical system is housed in the exterior case of the projector, it is possible to design with a high degree of spatial freedom in arrangement including the electric circuit board that is a projector component other than the optical system. That is, it contributes to an external design with a rich design.

  Next, a fifth embodiment of the projector of the invention will be described with reference to the drawings. FIG. 16 is a schematic configuration diagram of the optical system of the fifth embodiment, and FIG. 17 shows the operation of the light beam reflected by the reflective polarizing plate of the optical system of the projector of the fifth embodiment of the invention. It is a typical block diagram for demonstrating.

  The difference between the fourth embodiment shown in FIGS. 14 and 15 and the fifth embodiment shown in FIGS. 16 and 17 is that the optical axis 471 of the first light guide member in the fifth embodiment. And the optical axis 472 of the second light guide member is that the optical axis is bent at a right angle in the middle using the first reflection mirror 441 and the second reflection mirror 442.

  Naturally, even with such a configuration, high polarization conversion efficiency and high light utilization efficiency are achieved. In this arrangement, the distance L in the optical axis direction of the illumination lens can be particularly shortened, so that the optical system can be made compact. As in the fourth embodiment, a part of the sectional optical path diagram is shown in FIG. Here, the drawing of light rays after the polarizing plate is omitted.

1 is a schematic configuration diagram of a projector including an optical system according to a first embodiment of the present invention. It is a typical block diagram of the optical system of the 1st Embodiment of this invention. It is a graph which shows the reflective characteristic of a selective reflection translucent film, (a) is the characteristic of the 1st selective reflection translucent film which reflects red and blue, (b) is the 2nd selection which reflects green It is the characteristic of a reflective translucent film. It is a perspective view which shows a rod integrator and the glass substrate in which the selective reflection translucent film was formed. It is a typical side view of a reflective polarizing plate. It is a typical block diagram for demonstrating operation | movement of the optical system of the projector of the 1st Embodiment of this invention. It is a typical block diagram for demonstrating operation | movement of the light beam reflected by the reflective polarizing plate of the optical system of the projector of the 1st Embodiment of this invention. Of the light beams emitted from the first rod integrator and the second rod integrator, the light transmitted through the reflective polarizing plate and reflected by the reflective polarizing plate are returned to the second rod integrator and the first rod integrator. FIG. 6 is an optical path diagram depicting both light that has been reflected and has reached the reflective polarizing plate again, and has undergone polarization conversion to reach the liquid crystal panel. It is a typical perspective view of the optical system of the projector of the 2nd Embodiment of this invention. It is a typical top view of the optical system of the projector of the 2nd Embodiment of this invention. It is a typical side view of the optical system of the projector of the 2nd Embodiment of this invention. It is a perspective view which shows the light source of the 2nd Embodiment of this invention, a rod integrator, and an auxiliary lens. It is a perspective view which shows the light source of the 3rd Embodiment of this invention, a rod integrator, and an auxiliary lens. It is a typical block diagram of the optical system of the 4th Embodiment of this invention. It is a typical block diagram for demonstrating operation | movement of the light beam reflected by the reflective polarizing plate of the optical system of the projector of the 4th Embodiment of this invention. It is a typical block diagram of the optical system of the 5th Embodiment of this invention. It is a typical block diagram for demonstrating operation | movement of the light beam reflected by the reflective polarizing plate of the optical system of the projector of the 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 2 Optical system 10 Illumination optical system 11, 111a, 111b, 111c, 211a, 211b, 211c, 311, 411 First light source 12, 112a, 112b, 112c, 212, 312, 412 Second light source 21, 121 221a, 221b, 221c, 321, 421 First rod integrator 22, 122, 222a, 222b, 222c, 322, 422 Second rod integrator 23, 123a, 123b, 123c, 223, 323, 423 First selection Reflective translucent film 24, 124a, 124b, 124c, 224, 324, 424 Second selective reflective translucent film 31, 131, 231, 331, 431 First auxiliary lens 32, 132, 232, 332, 432 Second Auxiliary lenses 33, 133a, 133b, 13 3c, 233, 333, 433 Third auxiliary lens 34, 134, 234, 334, 434 Fourth auxiliary lens 41 First illumination lens 42 Second illumination lens 51 Reflective polarizing plate 52 1/4 wavelength plate 53 Liquid crystal panel 54 Polarizing plate 55 Projection lens 61 Incident light beam 63 First reflected light beam 64 Second reflected light beam 71, 371, 471a, 471b Optical axes of first light guide member 72, 372a, 372b, 472a, 472b Second Optical axis of the light guide member 73 Illuminating lens optical axis 81 Rod integrator 82 Glass substrate 83 Selective reflective transparent film 91 Non-polarized light 92 Transmitted light (P-polarized light)
93 Reflected light (circularly polarized light)
135 Second auxiliary lens group 213a, 213b Third light source 214 Fourth light source 341 Reflecting mirror 441 First reflecting mirror 442 Second reflecting mirror

Claims (10)

A projector that projects the formed image by causing the first color light, the second color light, and the third color light from the light source to enter the single image forming element via the light guide member and the illumination lens. There,
A first light guide member provided with a selective reflection light-transmitting film that transmits the first color light and reflects the second color light and the third color light; and an optical axis of the first light guide member A first light source unit comprising a first light source that is arranged to emit the first color light;
The optical axis of the illumination lens is provided at a position symmetrical to the first light guide member and the first light source, and the second color light and the third color light are transmitted through the first light guide member and the first light source. A second light guide member provided with a selective reflection light-transmitting film that reflects one color light; and the second color light and the third color light arranged on an optical axis of the second light guide member. A second light source unit comprising a second light source that selectively emits light and forms the light source together with the first light source;
A reflective polarizing plate that is provided between the illumination lens and the image forming element and transmits the first polarized light and reflects the second polarized light;
A retardation plate that converts reflected light from the reflective polarizing plate into circularly polarized light, and converts reflected light from the selective reflection light-transmitting film into the first polarized light;
Outgoing light and reflected light from the first light source unit are emitted to the reflective polarizing plate, and reflected light from the reflective polarizing plate is emitted to the selective reflection light-transmitting film of the second light source unit. The emitted light and the reflected light from the second light source unit are emitted to the reflective polarizing plate, and the reflected light from the reflective polarizing plate is emitted to the selective reflection transparent film of the first light source unit. And an optical system having an illumination lens group. The projector according to claim 1, wherein
The first light guide member of the first light source unit is provided with one or more combinations of the first light source unit and the second light source unit combined with the first light source unit. And the optical axis of the second light guide member of the second light source unit are arranged on the object with the optical axis of the illumination lens as an axis of symmetry, and a plurality of the first light guides. The projector, wherein the optical axis of the member and the optical axes of the plurality of second light guide members are arranged on the same plane. The projector according to claim 2,
There are two or more combinations of the first light source unit and the second light source unit,
The second light source is divided into a third light source that emits the second color light and a fourth light source that emits the third color light, and the third light source and the fourth light source are respectively A projector disposed in the second light source unit so as to have a predetermined number. The projector according to any one of claims 1 to 3,
The projector, wherein the first color light is green, the second color light is red, and the third color light is blue. The projector according to any one of claims 1 to 4, wherein:
The projector, wherein the selective reflection light-transmitting film is formed on a glass substrate, and the glass substrate is disposed on either the incident side or the emission side of the light guide member. The projector according to claim 1, wherein
The illumination lens group includes:
An auxiliary lens for a light source provided on each emission side of the first light guide member and the second light guide member, and
Light emitted from the auxiliary lens on the first light guide member side is emitted to the reflective polarizing plate, and reflected light from the reflective polarizing plate passes through the auxiliary lens on the second light guide member side. Then, the light is emitted to the selective reflection light-transmitting film of the second light guide member, the light emitted from the auxiliary lens on the second light guide member side is emitted to the reflective polarizing plate, and the reflective polarized light is emitted. Reflected light from the plate is emitted from the first illumination lens and the second illumination lens that are emitted to the selective reflection light-transmitting film of the first light guide member via the auxiliary lens of the first light guide member. Constructed projector. The projector according to any one of claims 1 to 6,
A projector, wherein the single-plate image forming element is a single liquid crystal panel. The projector according to any one of claims 1 to 7,
The projector, wherein the first to fourth light sources are light emitting diodes. The projector according to any one of claims 6 to 8,
A reflection mirror that converts the optical axis of the second light guide member into a direction perpendicular to the optical axis of the illumination lens;
The projector, wherein the second light source, the second rod integrator, and the auxiliary lens are provided on the optical axis of the second light guide member converted by the reflection mirror. The projector according to claim 9, wherein
A reflection mirror that converts the optical axis of the first light guide member into a direction perpendicular to the optical axis of the illumination lens;
A projector, wherein the first light source, the first rod integrator, and the auxiliary lens are provided on an optical axis of the first light guide member converted by the reflection mirror.

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