JP2005121735A - Illuminator and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator small in size and light in weight and also radiating a large quantity of light, and a projector using the same. <P>SOLUTION: The illuminator is equipped with a plurality of light sources emitting colored light beams having different wavelengths, and a wavelength composing means 12 having a plurality of colored light beam selecting films 14r, 14g and 14b selectively transmitting and reflecting two incident color light beams having the different wavelengths and emitting the transmitted color light beam and the reflected color light beam in the same direction. In the illuminator, at least four or more light incident surfaces 13r, 13g1, 13g2 and 13b on which the color light beams are made incident are formed in the wavelength composing means 12, and the light sources are arranged so that the color light beams respectively having the different wavelengths may be made incident on the light incident surfaces 13r, 13g1, 13g2 and 13b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  In conventional projectors (projection display devices), a halogen lamp has been used as a light source in the past, and a high-pressure mercury lamp (UHP) having high luminance and high efficiency has been used in recent years. A light source using UHP, which is a discharge lamp, requires a high-voltage power circuit, is large and heavy, and hinders the reduction in size and weight of the projector. Further, although it has a longer life than a halogen lamp, it still has a short life, and it is almost impossible to control the light source (fast lighting, extinguishing, modulation), and it takes a long time to start up.

Therefore, recently, an LED illuminant has attracted attention as a new light source. LEDs are ultra-compact, ultra-light, and have a long life. In addition, by controlling the drive current, it is possible to freely turn on / off and adjust the amount of emitted light. In this respect, it is also promising as a light source for projectors, and application development has already started for small and portable small screen projectors.
However, LEDs are about 1/2 to 1/3 of UHP in efficiency, and it is difficult to irradiate a sufficient amount of light as a light source for a projector. In particular, an LED that emits green (G) color light has a small amount of light that can be emitted, and various techniques have been proposed to compensate for the insufficient light amount of G color light (see, for example, Patent Documents 1 and 2).
JP-A-11-32278 JP 63-118717 A

  In the said patent document 1, the shortage of G color light is compensated by increasing the number of LED which radiate | emits G color light. However, when the number of LEDs is increased, the light emitting point increases (the etendue increases), so that the illumination efficiency as an optical system is lowered, and it is difficult to obtain a large effect and it is difficult to irradiate a large amount of light. In addition, there is a problem that the efficiency seen from the input power is further reduced.

  Further, when a dichroic film having wavelength selectivity is used, even if the number of LEDs is increased, the light emitting point does not increase, and etendue does not increase. Patent Document 2 discloses an example in which the cross dichroic prism having the dichroic film is used for a projector. In the cross dichroic prism, colored light of different wavelengths is incident on three surfaces of the four surfaces other than the light emitting surface, so that the number of LEDs arranged on one surface can be increased. It was the upper limit of the number. Therefore, the amount of light that can be irradiated is affected by the size of the cross dichroic prism, and there is a problem that it is difficult to irradiate a large amount of light with a small size and light weight.

  The present invention has been made in order to solve the above-described problems, and an object thereof is to provide a lighting device that is compact and lightweight and can emit a large amount of light, and a projector using the same. .

  In order to achieve the above object, the illumination device of the present invention includes a plurality of light sources that emit color lights having different wavelengths and a plurality of color light selection films that selectively transmit and reflect the incident color lights having two different wavelengths. A wavelength synthesizing unit that emits the transmitted color light and the reflected color light in the same direction, and the wavelength synthesizing unit has at least four light incident surfaces on which the color light is incident. The light source is formed and arranged so that colored lights having different wavelengths are incident on the light incident surface.

That is, the illumination device of the present invention has at least four or more light incident surfaces, and includes wavelength synthesizing means for emitting incident color light in the same direction, so that at least four or more different color lights are emitted in a superimposed manner. Can be made. Therefore, the amount of light that can be emitted without increasing the etendue can be increased. For example, two G color lights having different wavelengths (G1 color light having a wavelength of 560 nm and G2 color light having a wavelength of 502 nm) are incident on the wavelength combining unit from different light incident surfaces, so that the etendue is not increased. Double G light can be emitted.
In addition, since the constituent elements are only the light source and the wavelength synthesizing unit that emit colored light having different wavelengths, it is suitable for reducing the size and weight of the lighting device.

More specifically, in order to realize the above configuration, the wavelength synthesizing unit is formed in a substantially cubic shape having a light emitting surface from which the transmitted color light and the reflected color light are emitted in the same direction, and the wavelength. A color light selection film is formed in the synthesizing unit so as to be substantially orthogonal to a surface adjacent to the light emitting surface and an intersection line with the adjacent surface is a substantially diagonal line of the adjacent surface. It is desirable that the color light selective film is formed so that the surface substantially orthogonal to both surfaces is substantially orthogonal to the surface, and the line of intersection with the orthogonal surface is a substantially diagonal line of the orthogonal surface.
According to this configuration, by forming the color light selection film in the wavelength synthesizing unit as described above, a surface other than the light emitting surface of the wavelength synthesizing unit can be used as the light incident surface. Therefore, at least four different color lights, and at most five different color lights can be superimposed and emitted, and the amount of light that can be emitted can be increased.

  A first projector of the present invention is a projector including an illumination device, a light modulation unit that modulates light from the illumination device, and a projection unit that projects light modulated by the light modulation unit. Is the lighting device of the present invention.

  That is, the first projector of the present invention includes the illumination device of the present invention, and the light modulation means is only the light modulation means for modulating the light emitted from the illumination device, so that the projector can be reduced in size and weight. It is suitable for aiming. In addition, since the lighting device of the present invention is provided, a bright image can be projected.

In order to realize the above configuration, more specifically, even when the light source of the illumination device alternately emits light for each light source that emits different color light, the light modulation unit performs modulation corresponding to the emitted color light. Good.
According to this configuration, for example, color light conversion means such as a color filter is not used, so that the components of the projector can be reduced, the projector can be reduced in size and weight, and a bright color image can be projected. be able to.

In order to realize the above-described configuration, more specifically, all the light sources of the lighting device may continuously emit light, and a color filter may be disposed in the light modulation unit.
According to this configuration, for example, the light modulation unit does not need to modulate each color light at a cycle faster than the image switching frequency in response to each color light that alternately emits light, and the display of the image becomes easy. Further, since there are few components of the lighting device, the projector can be reduced in size and weight, and a bright color image can be projected.

  A second projector according to the present invention includes the illumination device according to the present invention, a light modulation unit that modulates the color light emitted from the light source of the illumination device, a projection unit that projects the color light modulated by the light modulation unit, It is provided with.

  That is, the second projector according to the present invention includes the illumination device according to the present invention and modulates and combines the color lights emitted from the light sources, thereby improving the brightness of the projected image. it can. In addition, since the lighting device of the present invention is provided, the projector can be reduced in size and weight.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic plan view showing the overall configuration of the projector according to the present embodiment. In all the drawings below, the film thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.
The projector 1 of the present embodiment is a single-plate liquid crystal projector, and as shown in FIG. 1, a lighting device 10 and a color that converts white light emitted from the lighting device 10 into R, G, and B color lights. The filter 20 includes a transmissive liquid crystal light valve (light modulation means) 30 that modulates each converted color light, and a projection lens (projection means) 35 that projects each modulated color light.

  As shown in FIG. 1, the illumination device 10 includes light sources 11R and 11G1 that can continuously emit R (red), G1 (green: wavelength 502 nm), G2 (green: wavelength 560 nm), and B (blue) color lights simultaneously. , 11G2 and 11B, and a cross dichroic prism (wavelength synthesizing unit) 12 that emits white light by superimposing each color light.

FIG. 2 is a perspective view of the cross dichroic prism.
The cross dichroic prism 12 is formed in a substantially rectangular parallelepiped shape as shown in FIG. Each surface of the cross dichroic prism 12 includes a light emitting surface 13 that emits white light, a light incident surface 13g1 of colored light G1 that faces the light emitting surface 13, and a color light G2 that is adjacent to the light emitting surface 13 and the light incident surface 13g1. The light incident surface 13g2, the light exit surface 13 and the light incident surface 13r of the colored light R adjacent to the light incident surface 13g1, and the light incident surface 13b of the colored light B facing the light incident surface 13r are formed.

FIG. 3 is a diagram illustrating the reflection characteristics of each dichroic film.
Inside the cross dichroic prism 12, as shown in FIG. 3A, an R reflecting dichroic film (color light selection film) that reflects color light having a wavelength longer than the color light G1 and transmits color light having a wavelength shorter than the color light G1. ) 14r, and a B reflection dichroic film (color light selection film) 14b that reflects color light having a shorter wavelength than the color light G2 and transmits color light having a wavelength longer than the color light G2, as shown in FIG. 3B, As shown in FIG. 3C, a G reflective dichroic film (color light) that transmits color light having a wavelength equal to or greater than that of color light G1 and color light having a wavelength equal to or less than color light B and reflects color light having a wavelength substantially equal to that of color light G2. Selective film) 14g.

The R reflecting dichroic film 14r and the B reflecting dichroic film 14b are arranged so as to be orthogonal to the light incident surface 13g2 and the intersecting line thereof is a diagonal line of the light incident surface 13g2. The R reflecting dichroic film 14r is disposed away from the light incident surface 13r toward the light emitting surface 13, and the B reflecting dichroic film 14b is disposed away from the light incident surface 13b toward the light emitting surface 13. Yes.
The G-reflecting dichroic film 14g is arranged so as to be orthogonal to the light incident surface 13b and the intersection line is a diagonal line of the light incident surface 13b and is a diagonal line away from the light incident surface 13g2 toward the light emitting surface 13. ing.

  The light sources 11R, 11G1, 11G2, and 11B are configured by arranging LED chips that emit the respective color lights R, G1, G2, and B in an array, and are respectively positioned at positions facing the light incident surfaces 13r, 13g1, 13g2, and 13b. Has been placed. In addition, LED chips are disposed in the light sources 11R, 11G1, 11G2, and 11B in substantially the same shape as the light incident surfaces 13r, 13g1, 13g2, and 13b.

The color filter 20 is formed with a region for converting transmitted white light into any one of R, G, and B color light, and each region corresponds to a pixel that modulates each color light of the liquid crystal light valve 30 described later. Are arranged as follows.
The liquid crystal light valve 30 uses a TN (Twisted Nematic) mode active matrix type transmissive liquid crystal cell using a thin film transistor (hereinafter abbreviated as TFT) as a pixel switching element. The pixels of the liquid crystal light valve 30 are each composed of a set of pixels corresponding to R, G, and B color lights, and a predetermined intermediate color can be expressed by modulating each color light.

Next, the operation of the projector 1 having the above configuration will be described.
FIG. 4 is a schematic plan view showing superposition of each color light. FIG. 5 is a schematic side view showing the superposition of each color light.
The respective color lights R, G1, G2, B emitted continuously from the light sources 11R, 11G1, 11G2, 11B are respectively light incident surfaces 13r, 13g1, 13g2 of the cross dichroic prism 12, as shown in FIGS. , 13b.
The colored light R incident on the cross dichroic prism 12 is reflected by the R reflecting dichroic film 14r, and the other reflecting dichroic films 14g and 14b are transmitted and emitted from the light emitting surface 13. The colored light G1 passes through all the reflective dichroic films 14r, 14g, and 14b and is emitted from the light emitting surface 13. The colored light G2 is reflected by the G reflecting dichroic film 14g, and the other reflecting dichroic films 14r and 14b are transmitted and emitted from the light emitting surface 13. The colored light B incident on the light incident surface 13b is reflected by the B reflecting dichroic film 14b, passes through the R reflecting dichroic film 14r, and is emitted from the light emitting surface 13.

  The color lights R, G1, G2, and B simultaneously incident on the cross dichroic prism 12 from the light sources 11R, 11G1, 11G2, and 11B are superimposed in the cross dichroic prism 12 and emitted from the light exit surface 13 as white light. Is done. White light emitted from the cross dichroic prism 12 enters the color filter 20 and is converted into R, G, and B color light corresponding to each pixel of the liquid crystal light valve 30. Each converted color light is incident on a corresponding pixel of the liquid crystal light valve 30 and is modulated to be a color image. The color image is projected onto the screen 40 by the projection lens 35.

According to the above configuration, two G-color lights having different wavelengths (G1 color light having a wavelength of 560 nm and G2 color light having a wavelength of 502 nm) are incident from the light incident surface 13g1 and the light incident surface 13g2, and overlapped to form a light emitting surface. 13 can be emitted.
Therefore, approximately twice the amount of light can be emitted without increasing the etendue of the color light G.

Moreover, since the elements constituting the illumination device 10 are only the light sources 11R, 11G1, 11G2, and 11B and the cross dichroic prism 12, the illumination device 10 is suitable for reducing the size and weight.
Furthermore, by using the illumination device 10 for the single-plate projector 1, the projector 1 can be reduced in size and weight.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the projector of the present embodiment is the same as that of the first embodiment, but differs from the first embodiment in the driving method of the illumination device and the liquid crystal light valve, and the presence or absence of a color filter. . Therefore, in the present embodiment, only the periphery of the illumination device and the liquid crystal light valve will be described with reference to FIG. 6, and the description of the projection lens and the like will be omitted.
FIG. 6 is a schematic plan view showing the overall configuration of the projector according to the present embodiment.
The projector 2 according to the present embodiment is a single-plate type liquid crystal projector, and as shown in FIG. 6, an illumination device 10 ′ that alternately emits the respective color lights R, G 1, G 2, and B, and the emitted respective color lights. It is schematically composed of a transmissive liquid crystal light valve (light modulating means) 30 ′ that modulates color light, and a projection lens 35 that projects each modulated color light.

As shown in FIG. 6, the illumination device 10 ′ includes light sources 11 R ′ that can alternately emit R (red), G 1 (green: wavelength 502 nm), G 2 (green: wavelength 560 nm), and B (blue) color light, 11G1 ′, 11G2 ′, 11B ′, and a cross dichroic prism 12 that emits white light by superimposing each color light.
The liquid crystal light valve 30 ′ uses a TN (Twisted Nematic) mode transmissive liquid crystal cell using a thin film transistor (hereinafter abbreviated as TFT) as a pixel switching element. . The pixels of the liquid crystal light valve 30 can be modulated corresponding to each color light emitted alternately from the illumination device 10 '.

Next, the operation of the projector 2 having the above configuration will be described.
The light sources 11R ′, 11G1 ′, 11G2 ′, and 11B ′ of the illumination device 10 ′ emit light alternately, and the respective color lights R, G1, G2, and B are emitted and incident on the light incident surfaces 13r, 13g1, 13g2, and 13b. Is done. At this time, the light sources 11G1 ′ and 11G2 ′ emit light at the same time, and the color lights G1 and G2 are emitted simultaneously.
The color lights R, G1, G2, and B incident on the cross dichroic prism 12 are reflected and transmitted through the reflection dichroic films 14r, 14g, and 14b and alternately emitted from the light emitting surface 13.
The colored lights G 1 and G 2 are simultaneously incident on the cross dichroic prism 12, overlapped from the light emitting surface 13, and emitted as colored light G.
The colored lights R, G, B that are alternated from the cross dichroic prism 12 enter the liquid crystal light valve 30 ′. The liquid crystal light valve 30 ′ modulates each color light according to the color lights R, G, and B incident alternately, and each modulated color light is projected onto the screen 40 by the projection lens 35.

  According to the above configuration, since it is not necessary to arrange other components such as a color filter between the cross dichroic prism 12 and the liquid crystal light valve 30 ′, the projector 2 can be reduced in size and weight. .

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
The basic configuration of the projector in the present embodiment is the same as that of the first embodiment, but the number and arrangement positions of the liquid crystal light valves are different from those of the first embodiment. Therefore, in the present embodiment, only the periphery of the liquid crystal light valve will be described with reference to FIG. 7, and the description of the projection lens and the like will be omitted.
FIG. 7 is a schematic plan view showing the overall configuration of the projector according to the present embodiment.
The projector 3 of the present embodiment is a three-plate type liquid crystal projector, and as shown in FIG. 7, a transmissive type that modulates the respective color lights R, G1, G2, and B emitted from the light sources 11R, 11G1, 11G2, and 11B. Liquid crystal light valves (light modulation means) 31R, 31G1, 31G2, and 31B.

The liquid crystal light valves 31R, 31G1, 31G2, and 31B are disposed between the corresponding light sources 11R, 11G1, 11G2, and 11B and the light incident surfaces 13r, 13g1, 13g2, and 13b of the cross dichroic prism 12, respectively.
In addition, the liquid crystal light valves 31R, 31G1, 31G2, and 31B are TN (twisted nematic) mode active matrix transmission type using a thin film transistor (hereinafter abbreviated as TFT) as a pixel switching element. A liquid crystal cell is used.

Next, the operation of the projector 3 having the above configuration will be described.
FIG. 8 is a schematic plan view showing superposition of each color light. FIG. 9 is a schematic side view showing the superposition of each color light.
The respective color lights R, G1, G2, B emitted continuously from the light sources 11R, 11G1, 11G2, 11B enter the liquid crystal light valves 31R, 31G1, 31G2, 31B, respectively, as shown in FIGS. . Each color light incident on the liquid crystal light valves 31R, 31G1, 31G2, and 31B is modulated based on the image signal and is incident on the light incident surfaces 13r, 13g1, 13g2, and 13b of the cross dichroic prism 12.
The color light R incident on the cross dichroic prism 12 is reflected by the R reflecting dichroic film 14r and emitted from the light emitting surface 13. The colored light G1 passes through all the reflective dichroic films 14r, 14g, and 14b and is emitted from the light emitting surface 13. The colored light G2 is reflected by the G reflecting dichroic film 14g and emitted from the light emitting surface 13. The colored light B incident on the light incident surface 13 b is reflected by the B reflecting dichroic film 14 b and emitted from the light emitting surface 13.

  The color lights R, G1, G2, and B incident on the cross dichroic prism 12 are superimposed in the cross dichroic prism 12 and emitted from the light exit surface 13 as a color image. The color image emitted from the light exit surface 13 enters the projection lens 35 and is projected onto the screen 40.

  According to the above configuration, the color lights R, G1, G2, and B emitted from the light sources 11R, 11G1, 11G2, and 11B are modulated by the liquid crystal light valves 31R, 31G1, 31G2, and 31B, respectively, and then combined. The brightness of the projected image can be further improved.

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 above embodiment, the description has been made by adapting to the configuration in which the LED chips are arranged in the array shape as the light source. However, the configuration is not limited to the configuration in which the LED chips are arranged in the array shape, and uses one LED. The present invention can be applied to various other configurations.

1 is a schematic plan view showing an overall configuration of a projector according to an embodiment. It is a perspective view of a cross dichroic prism. It is a figure explaining the reflective characteristic of each dichroic film. It is a schematic plan view which shows the superimposition of each color light. It is a schematic side view which shows the superimposition of each color light. 1 is a schematic plan view showing an overall configuration of a projector according to an embodiment. 1 is a schematic plan view showing an overall configuration of a projector according to an embodiment. It is a schematic plan view which shows the superimposition of each color light. It is a schematic side view which shows the superimposition of each color light.

Explanation of symbols

1, 2, 3 ... projector, 10, 10 '... lighting device, 11R, 11G1, 11G2, 11B, 11R', 11G1 ', 11G2', 11B '... light source, 12 ... cross dichroic Prism (wavelength synthesizing means), 13 ... light emitting surface, 13r, 13g1, 13g2, 13r ... light incident surface, 14r ... R reflective dichroic film (color light selective film), 14g ... G reflective dichroic Film (color light selection film), 14b ... B reflective dichroic film (color light selection film), 20 ... color filter, 30, 30 ', 31R, 31G1, 31G2, 31B ... liquid crystal light valve (light modulation means) 35) Projection lens (projection means)

Claims (6)

A plurality of light sources that emit colored light of different wavelengths;
A wavelength synthesizing unit that includes a plurality of color light selection films that selectively transmit and reflect two incident color lights of different wavelengths, and the transmitted color light and the reflected color light are emitted in the same direction;
A lighting device comprising:
The wavelength synthesizing unit has at least four light incident surfaces on which colored light is incident,
The illuminating device, wherein the light source is arranged so that colored lights having different wavelengths are incident on the light incident surface. The wavelength synthesizing means is formed in a substantially cubic shape having a light emitting surface from which the transmitted color light and the reflected color light are emitted in the same direction,
In the wavelength synthesizing means, the color light selection film is formed so as to be substantially orthogonal to a surface adjacent to the light emitting surface and an intersection line with the adjacent surface is a substantially diagonal line of the adjacent surface,
Further, the color light selection film is formed so that the surface substantially orthogonal to both the light emitting surface and the adjacent surface is substantially orthogonal, and the line of intersection with the orthogonal surface is a substantially diagonal line of the orthogonal surface. The lighting device according to claim 1, wherein A projector comprising: an illuminating device; a light modulating unit that modulates light from the illuminating device; and a projecting unit that projects light modulated by the light modulating unit,
3. The projector according to claim 1, wherein the lighting device is the lighting device according to claim 1. The light source of the illuminating device alternately emits light for each light source emitting different color light,
4. The projector according to claim 3, wherein the light modulation means performs modulation corresponding to the emitted color light. All the light sources of the lighting device emit light continuously,
The projector according to claim 3, wherein a color filter is disposed in the light modulation unit.   An illumination device according to claim 1, a light modulation unit that modulates the color light emitted from the light source of the illumination device, and a projection unit that projects the color light modulated by the light modulation unit. A projector characterized by that.

Images