JP2009288387A - Projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type display device capable of simultaneously intercepting luminous fluxes from a main light source and an auxiliary light source by using the conventional light shielding type light control means even when the display device is equipped with the main light source and the auxiliary light source, and keeping white balance constant even when light control is performed. <P>SOLUTION: The projection type display device includes the main light source, the auxiliary light source, a splitting reflection means, a first integrator, a second integrator, a light control device, a condenser lens, an optical modulation element and a projection lens. In the display device, the splitting reflection means is arranged between the main light source and the first integrator, is composed of a plurality of reflection films arranged discretely on the optical axis of the auxiliary light source, and reflects the light from the auxiliary light source to the first integrator side after splitting it to one or more arrays of small lenses of the first integrator, whereby light from the auxiliary light source is combined with light from the main light source. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a projection display device, and more particularly to an illumination optical system of a projection display device using a liquid crystal display element.

In a conventional projection display device, a method has been proposed in which the light intensity in the wavelength region where the main light source is insufficient is supplemented from the integrator optical system using an auxiliary light source (see, for example, Patent Document 1).
On the other hand, a method of providing a light control device that reduces the amount of light in the optical path in order to improve contrast has been proposed (see, for example, Patent Document 2).
JP 2004-133195 A JP 2004-69966 A

  However, when the auxiliary light source is synthesized from the integrator optical system in the conventional configuration, if the light is blocked by the light control device, the light beam of the main light source is blocked, but the light beam of the auxiliary light source is not blocked. There was a problem that a difference in the amount of light of the light source occurred and the white balance was lost.

  The present invention solves the conventional problem, and enables the light from the main light source and the auxiliary light source to be simultaneously shielded even if a conventional light control device using light shielding is used, and the white balance is constant even if light control is performed. An object of the present invention is to provide a projection display device that can be maintained.

  In order to solve the conventional problem, the projection display device of the present invention has a main light source that emits main illumination light by a predetermined emission spectrum that is white, and an emission spectrum that is different from the main illumination light. , An auxiliary light source that emits sub illumination light to compensate for a wavelength region that is insufficient in light quantity in the emission spectrum of the main illumination light, and split reflection for combining the light of the auxiliary light source with the main light source Means, a first integrator for illuminating light emitted from the two light sources substantially uniformly, a second integrator, and a condenser lens for stacking the substantially uniform illumination light on the optical modulation element; A light control device that mechanically reduces the amount of light, an optical modulation element that modulates based on a video signal, and a projection lens that enlarges and projects the light modulated by the optical modulation element.

  Further, the first integrator includes a plurality of reflective films disposed between the main light source and the first integrator and discretely disposed on the optical axis of the auxiliary light source. The auxiliary light source and the divided reflection means for combining the light of the main light source are provided by dividing and reflecting in one or more rows of lenses.

  Further, in the projection display device according to claim 2 of the present invention, the light control device is arranged between the first integrator and the second integrator.

  In the projection display device according to claim 3 of the present invention, the light control device is disposed in the vicinity of a pupil position of the projection lens.

  Further, in the projection type display device according to claim 4 of the present invention, the split reflection means is composed of a prism array in which parallelogram prisms are joined in a strip shape, and a predetermined reflectance is provided on the joint surface of the parallelogram prisms. In this case, the reflected light width of the reflective film coincides with the small lens width of the first integrator section.

  Further, in the projection type display device according to claim 5 of the present invention, the reflective film of the split reflection means reflects only the wavelength range of the auxiliary light source and transmits the wavelength of the main light source other than the auxiliary light source. It is characterized by having.

Further, the reflectance Rn of the reflective film according to claim 6 of the present invention satisfies the following formula 1.
N: Total number of reflecting surfaces n: Number of reflecting surfaces (1, 2, 3,... From the side closer to the light source)
Rn = 1 / (N- (n-1)) * 100 (%) Formula 1
Further, the light intensity distribution of the auxiliary light source emitted from the split reflection means according to claim 7 of the present invention is emitted with the same light intensity distribution as that of the main light source.

  According to the projection type display device of the present invention, it is possible to simultaneously block the light of the main light source and the auxiliary light source even if a conventional light control device is used, and the white balance can be kept constant.

  Embodiments of a projection display device according to the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
The main configuration of the projector will be described.

  FIG. 1 is a plan view of a projection display device according to Embodiment 1 of the present invention. The projection display device includes a main light source unit including an electrodeless lamp 1 and a collimator lens 2, a laser 3, and a collimator lens 4. An auxiliary light source unit (see FIG. 2), a split reflection means 5 that combines the light of the main light source and the auxiliary light source, an illumination optical system 100 that forms illumination light for illuminating the liquid crystal display element 15, and illumination Color separation optical system 200 that separates light into red, green, and blue, liquid crystal display elements 15R, 15G, and 15B that modulate in accordance with video signals, color composition system 30 that synthesizes the separated light, and liquid crystal display element The projection display device includes a projection lens 31 that magnifies and projects light modulated by 15R, 15G, and 15B.

  Next, the main configuration of the illumination optical system will be described.

  FIG. 2 shows a side view of the illumination optical system of the projection display apparatus according to Embodiment 1 of the present invention.

  FIG. 3 is a front view of the first integrator 6 of the illumination optical system according to Embodiment 1 of the present invention.

  The illumination optical system includes a first integrator 6, a light control device 7, a second integrator 8, a polarization conversion element 9, and a condenser lens 10. The first integrator 6 has a function as a light beam splitting optical element that splits the light from the main light source 1 into a plurality of partial light beams, and is composed of a plurality of small lenses arranged in a matrix. The second integrator 8 has a function of forming the image of the small lens of the first integrator 6 together with the condenser lens 10 in the vicinity of the image forming area of the liquid crystal display device, and is arranged in a matrix like the first integrator. Consists of small lenses.

  The light control device 7 is a device that performs light control by shutter blades that partially shield the secondary light source formed on the second integrator. By adjusting the amount of light according to the input image signal, the image can be brightened by not reducing the amount of light in a bright image scene, and the image can be made darker by reducing the amount of light in a dark image scene. it can.

  The polarization conversion element 9 is an element that emits the polarization direction of each partial light beam divided by the first integrator 6 as approximately one type of linearly polarized light having the same polarization direction.

  The condenser lens 10 collects a plurality of partial light beams that have passed through the first integrator 6, the second integrator 8, and the polarization conversion element 9 and superimposes them in the vicinity of the image forming regions of the liquid crystal display devices 15R, 15G, and 15B. It is.

  Next, the main configuration of the color separation optical system will be described.

  In FIG. 1, the color separation optical system 200 includes dichroic mirrors 11 and 17, reflection mirrors 12, 23 and 25, a first relay lens 22, and a second relay lens 24.

  The color separation optical system 200 separates the illumination light beam emitted from the condenser lens 10 into three color lights of red light, green light, and blue light, and each of the three color liquid crystal display devices 15R to be illuminated is provided. It has the function of leading to 15G and 15B.

  The dichroic mirrors 11 and 17 are optical elements on which a wavelength selection film that reflects a light beam in a predetermined wavelength region and transmits a light beam in another wavelength region is formed on a substrate. The dichroic mirror 11 disposed in the front stage of the optical path is a mirror that reflects a blue light component and transmits other color light components. The dichroic mirror 17 disposed in the latter stage of the optical path is a mirror that reflects the green light component and transmits the red light component. The blue light component reflected by the dichroic mirror 11 is bent by the reflection mirror 12, and enters the image forming area of the liquid crystal display device 15B for blue light via the condenser lens 13B. The condenser lens 13B is provided to convert each partial light beam from the condenser lens 10 into a light beam substantially parallel to each principal ray. The condensing lenses 13G and 13B arranged in the preceding stage of the optical paths of the other liquid crystal display devices 15R and 15G are configured in the same manner as the condensing lens 13B.

  Of the green light component and red light component transmitted through the dichroic mirror 11, the green light component is reflected by the dichroic mirror 17, passes through the condenser lens 13G, and enters the image forming area of the green light liquid crystal display device 15G. . On the other hand, the red light component passes through the dichroic mirror 17 and passes through the first relay lens 22, the incident-side reflection mirror 23, the second relay lens 24, the emission-side reflection mirror 25, and the condenser lens 13R, and thus red light. Is incident on the image forming area of the liquid crystal display device 15R. The first relay lens 22, the second relay lens 24, and the reflection mirrors 23 and 25 have a function of guiding the red light component transmitted through the dichroic mirror 17 to the liquid crystal display device 15R.

  Next, a liquid crystal display device will be described.

  In FIG. 1, liquid crystal display devices 15R, 15G, and 15B modulate an illumination light beam according to image information, and are illumination targets of the illumination optical system 100. The liquid crystal display devices 15R, 15G, and 15B are obtained by sealing and enclosing a liquid crystal that is an electro-optical material in a pair of transparent glass substrates. For example, a polysilicon TFT is used as a switching element according to given image information. The polarization direction of one type of linearly polarized light emitted from the polarizing plates 14R, 14G, and 14B is modulated.

  In addition, incident-side polarizing plates 14R, 14G, and 14B are interposed between the condenser lenses 13R, 13G, and 13B and the liquid crystal display devices 15R, 15G, and 15B, respectively, and the liquid crystal display devices 15R, 15G, and Between the side 15B and the cross dichroic prism 30, exit-side polarizing plates 16R, 16G, and 16B are respectively disposed. The incident-side polarizing plates 14R, 14G, and 14B, the liquid crystal display devices 15R, 15G, and 15B and the emission-side polarizing plates 16R, 16G, and 16B perform light modulation of the incident color lights.

  Next, the color composition system will be described.

  In FIG. 1, the color synthesis system includes a cross dichroic prism 30. The cross dichroic prism 30 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from the exit-side polarizing plates 16R, 16G, and 16B. The cross dichroic prism 30 has a substantially square shape in plan view in which four right angle prisms are bonded together, and a dielectric multilayer film is formed on the substantially X-shaped interface in which the right angle prisms are bonded together.

  The dielectric multilayer film formed at one of the substantially X-shaped interfaces reflects red light, and the dielectric multilayer film formed at the other interface reflects blue light. By these dielectric multilayer films, the red light and the blue light are bent and aligned with the traveling direction of the green light, so that the three color lights are synthesized. The color image emitted from the cross dichroic prism 30 is enlarged and projected by the projection lens 31 to form a large screen image on the screen.

  Next, the reflection division means will be described.

  First, the reflection division means will be described in detail.

  FIG. 4 shows a side view and an optical path diagram of the reflection division means in Embodiment 1 of the present invention.

  In FIG. 4, the split reflecting means is a split reflecting prism 5 composed of a prism array in which parallelogram prisms are joined in a strip shape, and the joining surface 32 is provided with a reflecting film.

  The split reflection prism 5 is disposed between the collimating lens 2 and the first integrator 6 as shown in FIG. The light from the main light source is collimated by the collimating lens 2 and irradiated to the entire area of the first integrator 6. Therefore, the light from the main light source is also applied to the split reflection prism 5, passes through the reflection split prism, and enters the first integrator 6.

  The light from the auxiliary light source 3 is collimated by the collimating lens 4 and enters the split reflection prism 5. Then, the first integrator 6 side is sequentially provided by the reflecting film provided for each small lens of the first integrator 6 so that light is incident on all the rows of small lenses at the center of the first integrator 6 indicated by hatching in FIG. Is reflected. The emitted light is combined with the light from the main light source and passes through the same optical path as the main light source. Therefore, the size and the number of prisms of the parallelogram prism of the split reflection prism are determined by the size of the small lens of the first integrator 6 and the number of small lenses arranged.

  The reflective film on the bonding surface 32 reflects only the wavelength component of the auxiliary light source 3 and transmits the wavelength components of the main light source other than the wavelength component of the auxiliary light source 3. The reflectivity of each reflective film differs depending on the reflective surface, and the reflectivity Rn of each reflective film is N: the total number of reflective surfaces n: the reflective film number so that the light intensity emitted from the divided reflective prism 5 is uniform. In the case of (1, 2, 3... From the side closer to the light source), Rn = 1 / (N− (n−1)) * 100 (%) is satisfied.

  As described above, in the first embodiment, the split reflecting means is arranged between the main light source 1 and the first integrator 6 and includes a plurality of reflecting films discretely arranged on the optical axis of the auxiliary light source. The light of the auxiliary light source 3 and the main light source 1 is synthesized by dividing the first integrator 6 into one or more rows of small lenses of the first integrator 6 and reflecting them, and both the main light source 1 and the auxiliary light source 3 are the first. The width of the light emitted from the integrator 6 becomes the same by the split reflection means, and the light control device 7 can simultaneously block the light of the main light source 1 and the auxiliary light source 3, and the light control of the auxiliary light source 3 is performed. Even if not, the white balance can be kept constant.

  In the first embodiment, the light control device 7 is disposed between the first integrator 6 and the second integrator 8 so that the light control device 7 of the illumination optical system 100 can block light, and the white balance is constant. Can be kept in.

  Further, in the first embodiment, the divisional reflecting means includes a prism array in which parallelogram prisms are joined in a strip shape, and a reflective film having a predetermined reflectance is applied to the joint surface of the parallelogram prisms. Since the reflected light width of the first integrator 6 matches the small lens width of the first integrator 6, the arrangement of the reflective film is facilitated, and the light of the auxiliary light source 3 is incident on each small lens, so that the liquid crystal display element 15R, The uniformity of the light incident on 15G and 15B can be increased.

  In the first embodiment, the reflectance Rn of the reflective film satisfies the above formula 1 so that the light emitted from the divided reflection means of the auxiliary light source 3 is made uniform, so that the light shielding blade of the light control device 7 is provided. The vertical and horizontal symmetry can be achieved, and unevenness of light intensity in the liquid crystal display elements 15R, 15G, and 15B can be reduced.

  In the first embodiment, the light shielding blade of the light control device 7 can also be formed by applying a reflection film that emits the light intensity distribution of the auxiliary light source 3 emitted from the divided reflection means with the same light intensity distribution as that of the main light source 1. Can be made symmetrical in the vertical and horizontal directions, and unevenness in light intensity in the liquid crystal display elements 15R, 15G, and 15B can be reduced.

(Embodiment 2)
FIG. 5 shows a plan view of a projection display apparatus according to Embodiment 2 of the present invention. The difference from the configuration of the first embodiment is that the light control device 38 is disposed in the vicinity of the pupil position of the projection lens 31.

  Since an image of the surface of the second integrator 8 is formed in the vicinity of the pupil position of the projection lens 31, the light control device is provided between the first integrator 6 and the second integrator 8 even by shielding the vicinity of the pupil position of the projection lens. The same effect as arranging 7 is obtained.

  Other aspects are the same as those described in the first embodiment.

  As described above, in the second embodiment, by arranging the light control device in the vicinity of the pupil position of the projection lens, light can be shielded in the light control device of the projection lens, and white balance can be kept constant. .

  In the present embodiment, only one central row of the first integrator 6 is incident. However, the present invention is not limited to this, and for example, the first integrator 6 shown in FIG. The split reflection prism 5 may be incident on a plurality of lens rows so as to be incident on the three rows shown.

  In the present embodiment, a reflective film is provided for each small lens. However, as a second modification, for example, as shown in FIG.

  In this embodiment, the main light source 1 is an electrodeless lamp and the auxiliary light source 3 is a laser. However, the present invention is not limited to this, and the main light source includes a reflector 40 as shown in FIG. The auxiliary light source 3 may be a light source having a narrow wavelength region such as a light emitting diode (LED).

  FIG. 9 shows a rear projection display using the projection display device according to the embodiment of the present invention.

  The light emitted from the rear projection display device 33 is reflected by the rear mirror 34 and applied to the transmission screen 35.

  FIG. 10 shows a front projector using the projection display device according to the embodiment of the present invention.

  The light emitted from the projection display device 36 is applied to the reflective screen 37.

  The projection display device according to the present invention is capable of simultaneously blocking the dimming of the main light source and the auxiliary light source even when using a conventional dimming device using light shielding, and can maintain a constant white balance. And is useful as a projection display device such as a front projector or a rear projection television.

The top view of the projection type display apparatus in Embodiment 1 of this invention 1 is a side view of an illumination optical system of a projection display apparatus according to Embodiment 1 of the present invention. The front view of the 1st integrator in Embodiment 1 of this invention Side view and optical path diagram of reflection division means in embodiment 1 of the present invention The top view of the projection type display apparatus of Embodiment 2 of this invention The figure of the modification 1 in embodiment of this invention The figure of the modification 2 in embodiment of this invention The figure of the modification 3 in embodiment of this invention The figure of the rear projection display using the projection type display apparatus in embodiment of this invention The figure of the front projector using the projection type display apparatus in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrodeless lamp 2 Collimator lens 3 Laser 4 Collimator lens 5 Division | segmentation reflective prism 6 1st integrator 7 Light control device 8 2nd integrator 9 Polarization conversion element 10 Condenser lens 11, 17 Dichroic mirror 12, 23, 25 Reflection mirror 13R, 13G , 13B Condensing lens 14R, 14G, 14B Incident side polarizing plate 15R, 15G, 15B Optical modulation element 16R, 16G, 16B Outgoing side polarizing plate 22 First relay lens 24 Second relay lens 30 Cross dichroic prism 31 Projection lens 32 Joint Surface 33 Rear projection type image projection device 34 Rear mirror 35 Transmission type screen 36 Projection type display device 37 Reflection type screen 38 Light control device 39 Super high pressure mercury lamp 40 Reflector 100 Illumination optical system 200 Color separation optical system

Claims (7)

A wavelength that is insufficient in light quantity in the emission spectrum of the main illumination light due to a main light source that emits the main illumination light with a predetermined emission spectrum that is white, and an emission spectrum that is different from the main illumination light An auxiliary light source that emits auxiliary illumination light to supplement the area, a first integrator and a second integrator for substantially uniformly illuminating the light emitted from the two light sources, and substantially uniform illumination light A condenser lens for stacking on the optical modulation element, a light control device that mechanically reduces the amount of light, an optical modulation element that modulates based on a video signal, and a projection that enlarges and projects the light modulated by the optical modulation element A lens,
A plurality of reflective films disposed between the main light source and the first integrator and discretely disposed on the optical axis of the auxiliary light source, the light from the auxiliary light source toward the first integrator. A projection-type display device comprising: the auxiliary light source and divided reflection means for combining the light of the main light source by dividing and reflecting in one or more rows of small lenses of the integrator.   2. The projection display device according to claim 1, wherein the light control device is disposed between the first integrator and the second integrator.   2. The projection display device according to claim 1, wherein the light control device is disposed in the vicinity of a pupil position of the projection lens.   The divisional reflecting means comprises a prism array in which parallelogram prisms are joined in a strip shape, and a reflective film having a predetermined reflectance is applied to the joint surface of the parallelogram prism, and the reflected light width of the reflective film is The projection display device according to claim 1, wherein the projection type display device matches a small lens width of the first integrator unit.   2. The projection type according to claim 1, wherein the reflective film of the divided reflection unit reflects only the wavelength range of the auxiliary light source and transmits the wavelength of the main light source other than the auxiliary light source. Display device. The projection display device according to claim 5, wherein the reflectance Rn of the reflective film satisfies the following expression.
N: Total number of reflecting surfaces n: Number of reflecting surfaces (1, 2, 3,... From the closest to the auxiliary light source)

Rn = 1 / (N- (n-1)) * 100 (%)   6. The projection display device according to claim 5, wherein the light intensity distribution of the auxiliary light source emitted from the split reflection means is emitted with a light intensity distribution similar to that of the main light source.

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