JP2006227362A - Illuminating apparatus and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminating apparatus and a projector capable of enhancing light utilization with a simple constitution. <P>SOLUTION: The illuminating apparatus comprises; a light source 31R for emitting light; a reflection type polarizing element 34 for transmitting polarized light in a specified vibrating direction among the light emitted from the light source 31R, and reflecting polarized light in other vibrating directions different from the specified vibrating direction; a 1st reflecting part 15 arranged in a position away from the light source 31R, and on which the light reflected by the reflection type polarizing element 34 is made incident so as to reflect the incident light toward the reflection polarizing element 34; and a 2nd reflecting part 16 arranged in the light source 31R, for reflecting the light advancing to the light source 31R after being reflected by the element 34 toward the element 34. And the reflection polarizing element 34 is arranged so that the center light beam O of the light emitted from the light source 31R may form a prescribed angle with the normal line of the reflection polarizing element 34. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lighting device and a projector.

  In recent years, it has been proposed to use a solid state light emitting device as a light source of a projector. In particular, a light-emitting diode (hereinafter referred to as “LED”) that is a solid-state light-emitting element is characterized by being ultra-compact, ultra-light, and long-life. Further, LEDs have been improved in brightness and efficiency by development and improvement for use for illumination purposes. For this reason, in order to reduce the size and power consumption of the projector, it is expected to use an LED for the projector illumination device.

  As a projector using an LED, a projector is proposed in which a reflecting surface is provided on the incident end face of the rod integrator and a polarization conversion element is provided on the exit side of the rod integrator (see, for example, Patent Document 1). On the incident end face of the rod integrator provided in the projector described in Patent Document 1, an opening for allowing light to enter from a light source is provided. As a result, the light incident from the opening is reflected by the reflective polarizing element, guided again through the rod integrator, reflected by the reflective surface, and returned to the reflective polarizing element.

Also, a method using a PBS prism has been proposed as a method for aligning light emitted from the illumination device. In this method, light emitted from an LED is collimated by a collimator lens and then incident on a PBS prism. Of the light incident on the PBS prism, only polarized light in a specific vibration direction is transmitted, and other light rays are reflected, and the optical path is bent 90 degrees. Here, since the phase plate (λ / 2 plate) is provided on the optical path of the transmitted light first, the polarization direction changes, and as a result, the light having the same polarization direction can be obtained.
JP 2003-57445 A

However, in the technique described in Patent Document 1, an opening for allowing light from the light source to enter is provided on the incident end surface of the rod integrator, so that the light reflected by the reflective polarizing plate is opened. In some cases, the light recycling efficiency is reduced by the rod integrator. Furthermore, even if the light reflected by the reflective polarizing plate passes through the opening and sufficiently returns to the light source, the electrode serving as the reflective portion provided in the light source does not have a high light reflectance. For this reason, there is a problem that light loss occurs and the recycling efficiency decreases. In addition, in order to make the light from the arrayed LED efficiently enter the rod integrator, the rod integrator should be made large corresponding to the region where the LED is arranged, and a plurality of openings corresponding to the LED are made into the rod integrator. It is necessary to take measures such as installing in
Further, in the method of aligning the light emitted from the lighting device, the light emitted from the light source is reflected using the reflecting surface, so that the entire lighting device becomes large and the cost increases.

  SUMMARY An advantage of some aspects of the invention is that it provides a lighting device and a projector that can improve light use efficiency with a simple configuration.

In order to achieve the above object, the present invention provides the following means.
The illumination device of the present invention transmits a light source that emits light and polarized light having a specific vibration direction among the light emitted from the light source, and transmits polarized light having another vibration direction that is different from the specific vibration direction. A reflective polarizing element that reflects, and a first reflecting unit that is provided at a position spaced from the light source and that receives light reflected by the reflective polarizing element and reflects the light toward the reflective polarizing element And a second reflecting portion that is provided in the light source and reflects light that is reflected by the reflective polarizing element and travels in the direction of the light source, in the direction of the reflective polarizing element, and the reflective polarizer The reflective polarizing element is arranged such that a central ray of light from the incident light source forms a predetermined angle with respect to a normal line of the reflective polarizing element.

  In the illumination device according to the present invention, the light emitted from the light source is incident on the reflective polarizing element. Of the light incident on the reflective polarizing element, polarized light having a specific vibration direction is transmitted, whereas light having a vibration direction other than the specific vibration direction is reflected by the reflective polarizing element. Head in the direction. The light traveling from the reflective polarizing element toward the light source side is reflected by the first reflecting portion provided at a position separated from the light source, and travels again toward the reflective polarizing element. Then, light having a vibration direction other than a specific vibration direction out of the light incident on the reflective polarizing element is reflected by the reflective polarizing element, travels toward the light source, and is reflected by the second reflecting portion provided in the light source. Then, it proceeds again toward the reflective polarizing element. Here, the reflectance of the second reflecting portion cannot be made so high due to various restrictions, for example, the reflecting portion also serves as an electrode. On the other hand, in the present invention, since the first reflecting portion is provided independently at a position separated from the light source, a reflective polarizing element can be obtained by selecting a material having high reflectance as the first reflecting portion. It is possible to efficiently reflect the light reflected by the reflection type polarizing element again. Therefore, in the process in which the polarized light circulates (recycles) in the optical path between the first and second reflecting portions and the reflective polarizing element, the reflective polarizing element can efficiently extract polarized light in a specific vibration direction. Become.

Moreover, it is preferable that the illuminating device of this invention is equipped with the parallelizing optical system which makes the light inject | emitted from the said light source substantially parallel.
In the illuminating device according to the present invention, the light emitted from the light source is approximately collimated by the parallel light optical system, so that the light emitted from the light source is incident from a direction substantially perpendicular to the reflective polarizing plate. . That is, the light emitted from the light source can be efficiently separated by making the light incident from a direction substantially perpendicular to the reflective polarizing plate.

  In the illumination device of the present invention, the first reflecting portion is disposed adjacent to the light source, and the central ray of the light from the light source that has passed through the collimating optical system and the collimating optical system are provided. The light source and the first reflecting portion are arranged so that the angle formed between the central ray of the light reflected by the first reflecting portion that has passed and the optical axis of the collimating optical system is substantially equal. It is preferable.

  In the illuminating device according to the present invention, since the first reflecting portion is disposed adjacent to the light source, the light source and the first reflecting portion can be easily disposed, and the entire illuminating device can be made compact. It becomes. Further, by arranging the light source and the first reflecting portion so that the angles formed by the collimating optical system are substantially equal, the light reflected by the reflective polarizing element can be efficiently guided to the first reflecting portion. .

In the illumination device of the present invention, it is preferable that at least one of the light source and the first reflecting portion is inclined toward the optical axis of the collimating optical system.
In the illuminating device according to the present invention, at least one of the light source and the first reflecting unit is inclined toward the optical axis of the collimating optical system, and therefore there are few restrictions on the arrangement of the light source and the first reflecting unit. Therefore, productivity can be improved. In addition, the light source is tilted so that the light emitted from the light source is efficiently reflected by the first reflecting portion, and the light reflected by the reflective polarizing element is efficiently reflected by the first reflecting portion. As described above, the light use efficiency can be improved by inclining the first reflecting portion.

In the illumination device of the present invention, the light source is arranged so that a central ray of the light and an optical axis of the collimating optical system coincide with each other, and the reflective polarizing element is emitted from the light source. It is preferable to incline so that light may be reflected toward the first reflecting portion.
In the illuminating device according to the present invention, since the central ray of the light emitted from the light source coincides with the optical axis of the collimating optical system, the light emitted from the light source is efficiently reflected by the collimating optical system. Further, since the reflective polarizing element is inclined, more light can be reflected to the first reflecting portion.

A projector of the present invention includes the above-described illumination device, a spatial light modulation device that modulates light emitted from the illumination device in accordance with an image signal, and a projection device that projects light modulated by the spatial light modulation device. It is characterized by providing.
In the projector according to the present invention, the light emitted from the illumination device enters the spatial light modulation device. Then, the image modulated by the spatial light modulation device is projected by the projection device. At this time, the light emitted from the lighting device is aligned with the light that vibrates in a specific direction with high utilization efficiency as described above, so that the amount of light does not drop when passing through the spatial light modulation device. Therefore, it is possible to project an image having a uniform brightness while maintaining a high extinction ratio.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

Next, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the projector 1 of the present embodiment is a so-called front type projector that projects light according to an image signal onto a screen 60 and observes a projected image from the same side as the projector 1 with respect to the screen 60. is there.

  The projector 1 includes an R light illumination device (illumination device) 10R that emits red light (hereinafter referred to as “R light”) and a G light illumination that emits green light (hereinafter referred to as “G light”). A device (illumination device) 10G, a B light illumination device (illumination device) 10B for emitting blue light (hereinafter referred to as “B light”), and R emitted from each of the illumination devices 10R, 10G, and 10B. Transmission type liquid crystal light valves (spatial light modulators) 20R, 20G, and 20B that modulate the luminance of G and B according to an image signal, a dichroic prism 40 that combines the modulated color lights into a color image, and a dichroic A projection lens (projection device) 50 that projects a color image emitted from the prism 40 onto a screen 60 is provided.

  The R light illumination device 10R includes four light source units 11R, 12R, 13R, and 14R, rod integrators 21R, 22R, 23R, and 24R provided corresponding to the light source units 11R to 14R, and the rod integrators 21R to 21R, respectively. And a hollow rod integrator 25R disposed on the injection end face of 24R. Similarly, the G light illumination device 10G includes four light source units 11G, 12G, 13G, and 14G, and the B light illumination device 10B includes one light source unit 11B.

The rod integrators 21R to 24R are made of a transparent member such as solid glass or resin, and guide the light emitted from the light source units 11R to 14R to the hollow rod integrator 25R and totally reflect the light internally. By repeating, the illuminance distribution of the light emitted from the light source units 11R to 14R is made substantially uniform.
Moreover, the hollow rod integrator 25R is a hollow rod, and repeats total reflection on the inner surface of the aluminum-deposited rod, thereby making the illuminance distribution of the light emitted from the light source units 11R to 14R substantially uniform and transmitting liquid crystal light. The bulb 20R is irradiated with uniform illumination.

Next, the structure of each light source part 11R-14R is demonstrated using a simplified diagram as shown in FIG. Details of each of the light source units 11R to 14R will be described later with reference to FIG.
As shown in FIG. 2, each of the light source units 11R to 14R substantially parallelizes the light emitted from the R light LED (light source) 31R and the light emitted from the R light LED 31R. The collimator lens (collimating optical system) 32, the λ / 4 phase plate 33 disposed on the exit side of the collimator lens 32, and the λ / 4 phase plate 33 are in direct contact with and transmitted through the λ / 4 phase plate 33. Reflected polarizing plate (reflective polarizing element) 34 that transmits polarized light of a specific vibration direction out of the light and reflects polarized light of another vibration direction different from the specific vibration direction, and emitted from the R light LED 31R And a condensing lens 35 that collects the incident light and enters the rod integrator 21R. In FIG. 2, the λ / 4 phase plate 33 and the reflective polarizing plate 34 are arranged with an interval therebetween in order to easily understand the optical path of the light emitted from the R light LED 31 </ b> R.
The size of the light emitting portion of the R light LED 31R is about 4 mm × 2 mm.

The R light LED 31R is provided with a reflection mirror (first reflection portion) 15 adjacent to the light reflected from the reflective polarizing plate 34 and traveling toward the R light LED 31R toward the collimator lens 32. Yes. Further, the central ray O of the light emitted from the LED 31R for R light is bent by passing through the collimator lens 32, and is normal to the reflective polarizing plate 34 (in this embodiment, the central axis L of the light source unit 11R, ie, The reflective polarizing plate 34 is arranged so as to form a predetermined angle with respect to the optical axis L) of the collimator lens 32. At this time, in the present embodiment, the reflection mirror 15 is disposed adjacent to the R light LED 31R, and is reflected by the central ray O of the light emitted from the R light LED 31R and bent by the collimator lens 32 and the reflection mirror 15. The LED 31R for R light and the reflection mirror so that the angles (angle α and angle β shown in the figure) formed by the central ray M of the light bent by the collimator lens 32 and the optical axis L of the collimator lens 32 are substantially equal. It is preferable to arrange 15.
The central light beam O and the central light beam M are light beams emitted in parallel with the normal line L of the reflective polarizing plate 34 and light beams emitted from substantially the centers of the R light LED 31R and the reflection mirror 15. is there.

Further, the R light LED 31R is provided with a reflecting portion 16 (second reflecting portion) that reflects light reflected by the reflective polarizing plate 34 and traveling in the direction of the R light LED 31R toward the collimator lens 32. ing.
The reflection mirror 15 and the reflection part 16 are comprised by members with high light reflectivity, for example, metal members, such as aluminum and silver. By configuring the reflection mirror 15 and the reflection portion 16 with a metal member, the structure is excellent in heat resistance. Thereby, the light returned to the R light LED 31 </ b> R is reflected by the reflection mirror 15 or the reflection part 16 and travels again toward the collimator lens 32. Of the light that passes through the collimator lens 32 and enters the λ / 4 phase plate 33 again, circularly polarized light is converted into, for example, p-polarized light that is linearly polarized light. The p-polarized light that is polarized light in a specific vibration direction can pass through the reflective polarizing plate 34. On the other hand, the linearly polarized light that has been converted to another vibration direction different from the specific vibration direction by transmitting again through the λ / 4 phase plate 33 is reflected by the reflective polarizing plate 34 and passes through the circulation described above. It is supposed to repeat.

Next, details of the light source unit 11R will be described.
As shown in FIG. 3, the light source unit 11 </ b> R includes an R light LED 31 </ b> R, a collimator lens 32, a λ / 4 phase plate 33, a reflective polarizing plate 34, and a condenser lens 35 integrated by a support substrate 36. Light source unit.
The LED 31R for R light is in the form of a package on which a chip 31a is mounted. Further, the LED 31R for R light is provided with an LED fixing plate 37 that is fixed to the support substrate 36. The LED fixing plate 37 has a function of a circuit board for conducting. Further, the LED fixing plate 37 is movable in the X and Y directions (the optical axis L is the Z direction), and the position of the R light LED 31R can be adjusted. Further, the back surface 37 a of the LED fixing plate 37 is provided with a heat radiating plate 38 that is thermally connected and radiates heat generated when the R light LED 31 R emits light through the LED fixing plate 37.

The collimator lens 32 and the condensing lens 35 are composed of two pieces, and these are housed in the lens barrels 39a and 39b. These lens barrels 39a and 39b can be moved and adjusted in the Z direction.
The collimator lens 32 and the condensing lens 35 are configured as a two-sheet set, but may be one or three or more.

  Each of the light source units 11G to 14G has a G light LED 31G instead of the R light LED (light source) 31R, and the light source unit 11B has a B light LED 31B instead of the R light LED 31R. Other than the points, the light source units 11R to 14R have the same configuration.

  As shown in FIG. 1, the R light emitted from the hollow rod integrator 25R enters the transmissive liquid crystal light valve 20R. The cross section of the portion of the hollow rod integrator 25R through which light propagates has substantially the same shape as the modulation region of the transmissive liquid crystal light valve 20R. The hollow rod integrator 25R and the transmissive liquid crystal light valve 20R are joined to each other so that the R light emitted from the hollow rod integrator 25R is directly incident on the transmissive liquid crystal light valve 20R. The transmissive liquid crystal light valve 20R is a transmissive liquid crystal display device that modulates R light according to an image signal, and the light modulated by the transmissive liquid crystal light valve 20R is a cross dichroic that is a color synthesis optical system. The light enters the prism 40.

  The G light illumination device 10G is configured to emit G light in the plus Z direction shown in FIG. Light from the light source units 11G to 14G is guided to the hollow rod integrator 25G by the rod integrators 21G, 22G, 23G, and 24G. The G light from the hollow rod integrator 25G enters the transmissive liquid crystal light valve 20G. The hollow rod integrator 25G and the transmissive liquid crystal light valve 20G are joined to each other. The transmissive liquid crystal light valve 20G is a transmissive liquid crystal display device that modulates G light according to an image signal, and the light modulated by the G light spatial light modulator 20G is a color synthesis optical system. The light enters the cross dichroic prism 40.

  The B light illumination device 10B is configured to emit B light in the minus X direction shown in FIG. The light source unit 11B is provided in the minus Z direction substantially perpendicular to the emission direction of the B light from the B light illumination device 10B. A tapered rod 26 is provided on the emission side of the light source unit 11B. The taper rod 26 is a structure having an exit surface larger than the entrance surface, and is made of a transparent member. The B light from the light source unit 11 </ b> B is spread to the hollow rod integrator 27 by the taper rod 26. The taper rod 27 also functions to align light in the optical axis direction by total reflection at the interface. The light incident on the hollow rod integrator 27 is converted into an angle of 90 degrees by the triangular prism 28 and guided to the hollow rod integrator 25B. The intensity distribution of the B light illumination device 10B is made uniform by the configuration from the taper rod 26 to the hollow rod integrator 25B.

  The B light from the hollow rod integrator 25B enters the transmissive liquid crystal light valve 20B. The hollow rod integrator 25B and the transmissive liquid crystal light valve 20B are joined to each other. The transmissive liquid crystal light valve 20B is a transmissive liquid crystal display device that modulates B light according to an image signal. The light modulated by the transmissive liquid crystal light valve 20B enters the cross dichroic prism 40 which is a color synthesis optical system.

  In the cross dichroic prism 40, a dichroic film that reflects B light and transmits R light and G light and a dichroic film that reflects R light and transmits B light and G light are arranged orthogonally in an X shape. Configured. The cross dichroic prism 40 combines the R light, the G light, and the B light that are respectively modulated by the spatial light modulators 20R, 20G, and 20B. The light synthesized by the cross dichroic prism 40 is projected onto the screen 60 by the projection lens 50.

Next, a method of projecting an image on the screen 60 using the projector 1 of the present embodiment having the above configuration will be described.
Since the operation for each color light emitted from the R light LED 31R, the G light LED 31G, and the B light LED 31B is the same, the operation for the red light emitted from the R light LED 31R will be described. The description of the action of green light and blue light is omitted.

First, when a current is supplied to the R light LED 31R of the R light illumination device 10R, red light is emitted from the R light LED 31R toward the collimator lens 32 as shown in FIG.
The red light incident on the collimator lens 32 is collimated and incident on the reflective polarizing plate 34 to transmit only p-polarized light. At this time, as shown in FIG. 4, the optical path of the light emitted from the point A of the R light LED 31 </ b> R passes through the point B of the collimator lens 32, and C of the λ / 4 phase plate 33 and the reflective polarizing plate 34. Reach the point. Thereafter, the p-polarized light of the red light transmitted through the reflective polarizing plate 34 is collected by the condenser lens 35 and is incident on each of the rod integrators 21R to 24R. The optical path of the p-polarized light transmitted through the reflective polarizing plate 34 at this time passes through the point D of the condenser lens 35 and reaches the point E of the chip image.

  On the other hand, the s-polarized light of the red light reflected by the reflective polarizing plate 34 passes through the λ / 4 phase plate 33 and the collimator lens 32 and enters the reflection mirror 15. At this time, the optical path of the s-polarized light reflected by the reflective polarizing plate 34 passes through the B1 point of the collimator lens 32 and forms an image at the A1 point of the reflecting mirror 15. Thereafter, the red light incident on the reflection mirror 15 is reflected and travels toward the collimator lens 32 again.

As described above, the s-polarized light that does not pass through the reflective polarizing plate 34 travels between the reflective polarizing plate 34 and the reflecting portion 16, but passes through the λ / 4 phase plate 33 twice so that the phase is λ. / 2 will change. For this reason, a part of the linearly polarized light reflected by the reflective polarizing plate 34 is rotated by 90 degrees before being again incident on the reflective polarizing plate 34 and converted into p-polarized light. . The light thus converted into p-polarized light is transmitted through the reflective polarizing plate 34.
At this time, the optical path of the s-polarized light reflected by the reflecting mirror 15 passes through the point B2 of the collimator lens 32 and passes through the point C1 of the λ / 4 phase plate 33 and the reflective polarizing plate 34. Then, the light converted into p-polarized light passes through the reflective polarizing plate 34, passes through the point D of the condenser lens 35, and reaches the point E1 of the chip image.

  And the illuminance distribution of the light which guided the inside of the rod integrators 21R-24R and entered from each rod integrator 21R-24R is equalized by the hollow rod integrator 25R. Thereafter, the light emitted from the hollow rod integrator 25R enters the transmissive liquid crystal light valve 20R, is modulated based on the video signal input to the projector 1, and is emitted toward the dichroic prism 40.

  Similarly, p-polarized light of green light and p-polarized light of blue light modulated based on the video signal are also incident on the dichroic prism 40. These color lights are combined by a blue light reflecting dichroic film that reflects blue light and a red light reflecting dichroic film that reflects red light to form light representing a color image and emitted toward the projection lens 50. The projection lens 50 enlarges and projects light representing a color image toward the screen 60 and displays a color image.

  Here, as a comparison with the present embodiment, as shown in FIG. 5, the central ray O of the light emitted from the R light LED 31 </ b> R and the optical axis L of the collimator lens 32 are arranged so as not to coincide with each other without using the reflection mirror 15. The light source unit 65 will be described. In the case of this configuration, as in the case of the light source unit 11R described above, the optical path emitted from the point A of the R light LED 31R passes through the point B of the collimator lens 32, and the λ / 4 phase plate 33 and the reflective polarization The point C of the plate 34 is reached. Then, the optical path of the p-polarized light transmitted through the reflective polarizing plate 34 passes through the point D of the condenser lens 35 and reaches the point E of the chip image.

On the other hand, the optical path of the s-polarized light reflected by the reflective polarizing plate 34 passes through the B1 point of the collimator lens 32 and forms an image at the A1 point of the reflecting unit 16. Next, the optical path of the s-polarized light reflected from the reflecting portion 16 passes through the point B2 of the collimator lens 32 and passes through the point C1 of the λ / 4 phase plate 33 and the reflective polarizing plate 34. Then, the light converted into p-polarized light passes through the reflective polarizing plate 34, passes through the point D of the condenser lens 35, and reaches the point E1 of the chip image.
According to the light source unit 65 of the comparative example, when the reflectance of the reflecting unit 16 is low, for example, when the reflectance is 50%, the light returning to the reflective polarizing plate 34 has a light amount emitted from the R light LED 31R. The light usage efficiency is reduced by half.

According to the illuminating devices 10R, 10G, and 10B according to the present embodiment, since the reflection mirror 15 is provided independently at a position separated from the light source, a material having high reflectance is selected as the reflection mirror 15. Thus, the light reflected by the reflective polarizing plate 34 can be efficiently reflected by the reflective polarizing plate 34 again. Even if a material having high reflectivity is not selected as the reflecting mirror 15, the reflecting mirror 15 is provided independently at a position separated from the light source. It is possible to reflect without intervening, and it is possible to reduce a decrease in light use efficiency due to light absorption of the LED itself.
Therefore, in the process in which the polarized light circulates (recycles) in the optical path between the reflection mirror 15 and the reflection part 16 and the reflective polarizing plate 34, the reflective polarizing plate 34 can efficiently extract polarized light in a specific vibration direction. It becomes. Further, by using the illuminating devices 10R, 10G, and 10B, the light that is oscillated in a specific direction with high utilization efficiency is arranged, so that the amount of light is reduced when passing through the transmissive liquid crystal light valves 20R, 20G, and 20B. Therefore, an image with uniform brightness can be projected while maintaining a high extinction ratio.

In the present embodiment, the same effect as described above can be obtained without using the collimator lens 32. However, by providing the collimator lens 32, the light emitted from the R light LED 31R is substantially parallel by the collimator lens 32. Therefore, the light emitted from the R light LED 31R enters the reflective polarizing plate 34 from a substantially vertical direction. In this way, by allowing the light emitted from the R light LED 31R to enter the reflective polarizing plate 34 from a substantially perpendicular direction, the light emitted from the R light LED 31R can be efficiently separated.
Although the collimating lens 32 is used as the collimating optical system, the collimating lens 32 is not limited to this, and may be any one of a reflector and a combination of a collimator lens and a reflector. By providing any one of a collimator lens, a reflector, and a combination of a collimator lens and a reflector as the collimating optical system, the light emitted from the R light LED 31R can be converted into substantially parallel light.
Moreover, it is good also as a structure which excluded the rod integrator from illuminating device 10R, 10G, 10B.

(Second embodiment of projector)
Next, a second embodiment according to the present invention will be described with reference to FIG. In each embodiment described below, portions having the same configuration as those of the projector 1 according to the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
In the projector according to the present embodiment, the difference from the first embodiment is that in the second embodiment, in the light source unit 70, the R light LED 71R, the G light LED 71G, the B light LED 71B, and the reflection mirror 72 are collimators. This is a point inclined toward the optical axis L of the lens 32.
In this configuration, the light emitted from the R light LED 71R, the G light LED 71G, and the B light LED 71B is collimated by the collimator lens 32, passes through the λ / 4 phase plate 33, and travels toward the reflective polarizing plate 34. Then, the light reflected by the reflective polarizing plate 34 is reflected again toward the reflective polarizing plate 34 by the light reflected by the reflective mirror 72. Thus, since there are few restrictions on arrangement | positioning of LED71R for R light, LED71G for G light, LED71B for B light, and the reflective mirror 72, it becomes possible to improve productivity.

  Note that at least one of the LED 71R for R light, the LED 71G for G light, the LED 71B for B light, and the reflection mirror 72 only needs to be inclined toward the optical axis L of the collimator lens 32, as shown in FIG. The light source section 75 in which the LED 71R for R light, the LED 71G for G light, the LED 71B for B light, and the reflective polarizing plate 34 are inclined may be used. The reflection mirror 76 is disposed on the optical axis L of the collimator 32. According to these light source units 70 and 75, since at least one of the R light LED 71R, the G light LED 71G, the B light LED 71B, and the reflection mirrors 72 and 76 is inclined, the R light LED 71R and the G light LED 71G. The LEDs 71R, 71G, 71B are tilted so that the light emitted from the B light LED 71B is efficiently reflected by the reflection mirrors 72, 76, and the light reflected by the reflective polarizing plate 34 is reflected by the reflection mirror 72. , 76 so that the reflection mirrors 72 and 76 are tilted so that the light is efficiently reflected.

(Third embodiment of projector)
In the projector according to this embodiment, the difference from the first embodiment is that, in the third embodiment, as shown in FIG. 8, in the light source unit 80, the R light LED 81 R, the G light LED 81 G, and the B light LED 81 B are provided. The LED 81R, 81G, and 81B are arranged so that the central ray O of the light emitted from the LEDs 81R, 81G, and 81B coincides with the optical axis L of the collimator lens 32, and the reflective polarizing plate 34 includes the R light LED 81R and the G light LED 81G. , The light emitted from the B light LED 81B is inclined so as to be reflected toward the reflection mirror 82. In the present embodiment, the reflection mirror 82 is also tilted with respect to the central ray O.

  In this configuration, the light emitted from each of the LEDs 81R, 81G, and 81B and reflected by the reflective polarizing plate 34 is efficiently reflected by the reflective mirror 82 because the reflective polarizing plate 34 is inclined. Become. Further, by tilting the reflection mirror 82, the light reflected by the reflection mirror 82 can be guided to the reflection type polarizing plate 34 more efficiently.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the first embodiment, the reflection mirror 15 is disposed adjacent to the G light LED 31G, but a structure in which the G light LED 31G and the reflection mirror 15 are packaged side by side is preferable.
In addition, the R light illumination device 10R and the G light illumination device 10G include four light source units, and the B light illumination device 10B includes one light source unit. It is not restricted to this, It can change suitably according to a use.
Moreover, although the projection lens 50 was used as a projection apparatus, it is also possible to use a mirror projection system combining several mirrors.

It is a principal part perspective view which shows the projector which concerns on 1st Embodiment of this invention. It is explanatory drawing which shows the optical path of the light irradiated from the light source part of FIG. It is a principal part block diagram which shows the light source part of FIG. It is explanatory drawing which shows the optical path of the light irradiated from the light source part of FIG. It is explanatory drawing which shows the optical path of the light irradiated from the light source part as a comparative example. It is explanatory drawing which shows the optical path of the light irradiated from the light source part of the projector which concerns on 2nd Embodiment of this invention. It is a light source part of the modification of the projector which concerns on 2nd Embodiment of this invention, and is explanatory drawing which shows the optical path of the light irradiated from the light source part. It is explanatory drawing which shows the optical path of the light irradiated from the light source part of the projector which concerns on 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 10R ... R light illumination device (illumination device), 10G ... G light illumination device (illumination device), 10B ... B light illumination device (illumination device), 15, 72, 76, 82 ... Reflection mirror (First reflecting part), 16 ... reflecting part (second reflecting part), 20R, 20G, 20B ... transmissive liquid crystal light valve (spatial light modulator), 31R, 71R, 81R ... LED for R light (light source) ), 31G, 71G, 81B ... LED for G light (light source), 31B, 71B, 81B ... LED for B light (light source), 32 ... Collimator lens (parallelizing optical system), 34 ... Reflective polarizing plate (reflective type) Polarizing element), 50 ... Projection lens (projection device)

Claims (6)

A light source that emits light;
A reflective polarizing element that transmits polarized light in a specific vibration direction out of the light emitted from the light source and reflects polarized light in another vibration direction different from the specific vibration direction;
A first reflection unit provided at a position separated from the light source, and the light reflected by the reflective polarizing element is incident thereon, and reflects the light toward the reflective polarizing element;
A second reflection unit provided in the light source and configured to reflect the light reflected by the reflective polarizing element and traveling in the direction of the light source toward the reflective polarizing element;
The reflective polarizing element is arranged such that a central ray of light from the light source incident on the reflective polarizer makes a predetermined angle with respect to a normal line of the reflective polarizing element. Lighting device.   The illumination device according to claim 1, further comprising a collimating optical system that substantially collimates light emitted from the light source.   The first reflection unit is disposed adjacent to the light source, and is formed by a central ray of light from the light source that has passed through the parallelizing optical system and the first reflection unit that has passed through the parallelizing optical system. The light source and the first reflecting portion are arranged so that angles formed by a central ray of reflected light and an optical axis of the collimating optical system are substantially equal. The lighting device described.   The lighting device according to claim 2, wherein at least one of the light source and the first reflecting portion is inclined toward an optical axis of the collimating optical system.   The light source is arranged so that a central ray of the light and an optical axis of the collimating optical system coincide with each other, and light reflected from the light source by the reflective polarizing element is sent to the first reflecting portion. The lighting device according to claim 2, wherein the lighting device is inclined so as to be reflected. The lighting device according to any one of claims 1 to 5,
A spatial light modulation device that modulates light emitted from the illumination device in accordance with an image signal;
A projector comprising: a projection device that projects light modulated by the spatial light modulation device.

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