JP2001296603A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector which can easily attain low cost by dispensing with the use of an expensive projection lens. SOLUTION: In the projector provided having a light source and an optoelectronic device 60 which modulates light fluxes R, G, B emitted from the light source corresponding to image information, a plurality of converging elements 631A for converging incident light fluxes R, G, B are provided on an optical incident side surface of a substrate 611 of an optical incident side constituting the optoelectronic device 60. Furthermore, a plurality of optical path changing elements 651 for changing optical paths of the incident light fluxes R, B are provided on a surface of an opposite side thereof. Optical centers of respective optical path changing elements correspond to boundary parts of a plurality of the converging elements 631A. Since the direction of the main beams of the incident light fluxes R, B converged by the converging elements 631A is bent by the optical path changing elements 651, the angles of the beams R, B emitted from the optoelectronic device 60 can be made small to dispense with the use of the projection lens of a larger diameter, having a small F value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projector provided with a light source and an electro-optical device for modulating a light beam emitted from the light source in accordance with image information. The present invention can be used for a so-called single-plate type projector that separates the light into color lights and makes each color light incident on a single electro-optical device at a different angle to perform light modulation for each color light.

[0002]

2. Description of the Related Art As a projector capable of projecting and displaying a color image, besides a three-plate type projector having three independent electro-optical devices for each color light, a single-plate type projector that forms a color image with one electro-optical device Has been put to practical use. The single-panel type projector has an advantage that the size and cost of the device can be easily reduced.

There are various types of single-plate type projectors. One liquid crystal display device (electro-optical device) having a microlens array, such as a color liquid crystal display device disclosed in Japanese Patent No. 2622185, is used. Special arrangement 3
2. Description of the Related Art A single-plate type projector having a form of illuminating with color light separated by a dichroic mirror is known (hereinafter, an electro-optical device of such a form is referred to as a spatial color separation type electro-optical device, and a projector using the same). Is referred to as a spatial color separation type projector). This type of projector has high light use efficiency despite being a single-panel type,
Attention has been paid to the fact that bright projection images can be easily realized.

FIG. 8 shows a main part of such a spatial color separation type projector. As shown in FIG. 8, the spatial color separation type projector 110 includes three dichroic mirrors 131R that reflect red (R), green (G), and blue (B) color lights, respectively.
131G and 131B are arranged at different angles with respect to the incident direction of the light beam, and the respective color lights separated by the three dichroic mirrors 131R, 131G and 131B enter the electro-optical device 150 from different directions. It is configured as follows. For example, the electro-optical device 150
The green light G has an incident angle of 0 degree and the red light R has an incident angle β
At 0, the blue light B is incident at an incident angle -β0. In the electro-optical device 150, as shown in FIG.
Three rectangular pixel electrodes 1 corresponding to each color light of RGB
51R, 151G, and 151B are juxtaposed and these 3
1 for one pixel electrode 151R, 151G, and 151B.
One micro lens 153 is formed. Each color light incident on the micro lens 153 from a different direction is condensed by the micro lens 153, is incident on the corresponding pixel electrode 151R, 151G, 151B, is modulated for each color light, and then passes through the projection lens 190. To project and display a color projection image.

Therefore, in such a spatial color separation type electro-optical device 150, generally, three types of pixel electrodes 151R and 151G corresponding to red (R), blue (B), and green (G) color lights, respectively. , 151B are arranged side by side,
The size of each pixel is reduced to approximately one third as compared with the pixel of the electro-optical device used in the three-plate type projector, and the shape thereof is an elongated rectangular shape.

[0006]

When the light beam is narrowed down by the light condensing function of the lens, the higher the parallelism of the light beam incident on the lens and the shorter the focal length of the lens, the smaller the sectional size of the light beam. (Light beam diameter) can be reduced. Conversely, if the focal length of the lens increases, the cross-sectional dimension of the light beam necessarily increases. Therefore, in the spatial color separation type projector 110, the electro-optical device 15
0, the pixel electrodes 151R, 151G, 151 of the electro-optical device 150 can be used without reducing the light use efficiency.
In the case of miniaturizing B, the focal length of the microlens 153 is made shorter or the electro-optical device 15 is made smaller.
It is necessary to narrow the light beam more narrowly so that the light beam incident on 0 can be made more parallel and can pass through a pixel of a small size. However, as shown in FIG. 9, when such a short-focus microlens 153 is used, the divergence angle α0 of the light flux after condensing becomes extremely large. Furthermore, in the spatial color separation type projector 110, each of the RGB color lights separated by the color separation optical system enters the electro-optical device from a different direction with a certain angle (incident angle β0). The light beam from the device 150 becomes divergent light emitted at a maximum angle of α0 + β0 at the maximum. In order to collect the color light emitted at such a large angle (α0 + β0) with a projection lens without leakage and form a projection image, the F value of the lens can be small and the luminous flux diameter of each color light when it diverges can be included. It is necessary to use a large diameter projection lens, but such a lens is very expensive and
There is a problem that it is large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a projector which does not require an expensive projection lens and can be easily reduced in cost.

[0008]

To achieve the above object, a projector according to the present invention comprises a light source and an electro-optical device for modulating a light beam emitted from the light source in accordance with image information. The electro-optical device includes a light incident side substrate and a light exit side substrate, and an electro-optical element sandwiched between these substrates. The light incident side surface of the light incident side substrate includes A plurality of light-condensing elements for condensing a light beam to each pixel of the optical device and making the light beam incident on the surface of the light exit side are provided with a plurality of light path changing elements for bending the light path of the light beam incident on the electro-optical element, An optical center of each of the plurality of light path changing elements corresponds to a boundary between the plurality of light collecting elements. Here, as the light condensing element and the optical path changing element, an optical element such as a lens or a prism capable of refracting an incident light beam to bend its optical path can be adopted. Specifically, for example, a light exit side Can employ a negative lens or a prism having a flat end surface.

According to the present invention, since the light path changing element is provided, the light beam introduced into each pixel at a predetermined converging angle by the light condensing element is directed by the light path changing element in the direction of the principal ray. Are bent in a predetermined direction. Therefore, since the exit angle of the light beam emitted from the electro-optical device can be reduced, it is not necessary to use a large-diameter projection lens having a small F value, and the cost can be easily reduced. In particular, since the optical center of the light path changing element corresponds to the boundary of the light collecting element, it is easy to change the light path of the light beam incident from the light collecting element in a specific positional relationship with the light path changing element in substantially only one direction. In addition, the emission angle of light emitted from the electro-optical device can be made smaller.

[0010] In the above, it is preferable that an optical path unchanged area that does not change the optical path of the incident light beam is interposed between the adjacent optical path changing elements of the plurality of optical path changing elements.
Specifically, when the projector is provided with a color separation optical system that separates a light beam emitted from a light source into three types of color lights and makes each of the color lights enter the electro-optical device at a different angle, the light path unchanged area Is preferably formed so as to correspond to a position where only the color light that is incident on the light incident side substrate at right angles out of the three types of color light separated by the color separation optical system passes.

That is, in such a configuration of the projector, the color light that is substantially perpendicularly incident on the light incident side substrate of the electro-optical device is emitted from the electro-optical device at a substantially vertical angle. Therefore, since the light is emitted from the electro-optical device at a smaller angle (strictly, the absolute value of the angle is smaller) than the other two types of color light, it is not necessary to bend the direction of the principal ray by the optical path changing element. Therefore, by forming an optical path unchanged region corresponding to such vertically incident color light, light loss of the color light can be prevented, and the brightness of the projected image can be improved.

The above-described optical path changing element only needs to have a refractive index interface for refracting incident light in at least one direction along the surface of the light-incident side substrate. The separation direction of each color light by the color separation optical system, that is,
This is an arrangement direction of pixels according to each color light of the electro-optical device.
That is, in such an electro-optical device, three types of pixels assigned to each color light are arranged side by side to form a substantially square area, and a predetermined color display is performed using this area. The pixel to be modulated has a rectangular shape obtained by dividing the side of the substantially square area along the color separation direction by the color separation optical system into three. And the light condensing by the light condensing element
Since the purpose is to focus light at least in the arrangement direction of the pixels, the direction in which the principal ray of the light beam is bent by the optical path changing element may be only that direction. Therefore, the light flux changing element only needs to form a refractive index interface that refracts incident light only in this direction. For example, a lens is a cylindrical lens, and a prism is a triangular prism. The optical path changing element can be easily manufactured as an element.

Further, as the above-mentioned optical path changing element,
It is conceivable to change the optical path of the light beam condensed by a plurality of light condensing elements. Specifically, one light path is applied to a plurality of light beams from a plurality of light condensing elements arranged adjacent to each other. An optical path changing element arranged so as to correspond to a changing element (a lens, a prism, or the like) is conceivable. As described above, by sharing one optical path changing element with a plurality of light-collecting elements, the number of optical path changing elements provided on the incident side substrate can be reduced, so that the fabrication of the optical path changing element can be facilitated. it can.

On the other hand, the configuration of another optical path changing element is as follows.
An optical path changing element configured by a plurality of optical elements (lenses, prisms, and the like) and arranged so that one optical element corresponds to a light beam from one light-collecting element can be considered. As described above, since the optical element is arranged according to the light flux condensed by the light condensing element, a negative lens can be formed according to the optical characteristics of the condensed color light, so that light loss at the negative lens is reduced. As a result, the light use efficiency of the electro-optical device can be improved.

Preferably, the surface of the light incident side substrate on the light exit side is flattened. Here, as a method of flattening, a method of forming a flattening layer having a flat surface on the substrate surface, a method of forming an optical path changing element on the surface of the light incident side substrate, and then a method of CMP (Chemical Mechanical Polishing).
(shinging). The flattening layer can be constituted by a transparent dielectric layer made of SiO, SiO ₂ or the like.

That is, the light exit side surface of the light incident side substrate on which the light path changing element is provided is a surface that comes into contact with an electro-optical element such as a liquid crystal element sealed between the light incident side substrate and the light exit side substrate. In some cases, by flattening such a contact surface, the orientation of the electro-optical element on the contact surface is improved, and the characteristics of the electro-optical device can be improved.

When the optical path changing element comprises a negative lens, the negative lens can be configured so that the refractive index changes continuously in the thickness direction of the light incident side substrate. With this configuration of the negative lens, the light path of the light beam incident on the negative lens can be smoothly bent, so that the occurrence of light loss due to the interposition of the negative lens can be reduced, and the light utilization efficiency can be reduced. High projector.

Such a negative lens can be manufactured by an ion exchange method. For example, 1) a soda glass substrate serving as a substrate of an electro-optical device is sufficiently washed, and 2) an ion-impermeable material is transmitted to the surface of the glass substrate. A film having an effect, for example, a Ti film is formed, and 3) an opening having an appropriate pattern is formed in the Ti film by photolithography or the like. 4) The glass substrate is subjected to a molten salt for ion exchange treatment (for example, Tl, K,
By immersing in a nitrate containing a monovalent alkali metal such as Na), a negative lens can be formed at a position on the glass substrate corresponding to the opening. By forming the negative lens by such an ion exchange method, the size of the opening can be freely set by photolithography or the like, and a negative lens of a desired size can be formed on the glass substrate. This facilitates the manufacture of the substrate.

Further, as a negative lens other than the negative lens described above, a concave portion having an arc-shaped cross section is formed on the light exit side surface of the light incident side substrate. It is also conceivable that the material is filled with a material having a low refractive index. Here, as the low refractive index material to be filled in the concave portion, glass having a lower melting point than the glass substrate constituting the electro-optical device or a resin having high heat resistance can be adopted, and these electro-optical devices are manufactured. In this case, it is sufficient that no harmful damage is caused by the temperature conditions in each step.
Specifically, in the case of a liquid crystal panel, formation of a transparent conductive film,
Temperature in each step such as alignment film formation, 150 to 200 ° C.
If it can withstand the above, it can be adopted as a low refractive index material. Since the negative lens is made of a low-refractive-index material that fills a concave portion formed on the substrate, the contact surface of the substrate with the electro-optical element can be flattened, and the characteristics of the electro-optical device are improved as described above. can do. If the contact surface cannot be flattened only by filling with a low-refractive-index material, the flattening of the contact surface is ensured by the above-described flattening by CMP or by forming a flattening layer made of a dielectric layer. it can.

Further, as the above-mentioned negative lens,
An arc-shaped convex portion is formed on the light emitting side surface of the light incident side substrate, and the surface on which the convex portion of the light incident side substrate is formed is flattened with a material having a higher refractive index than the light incident side substrate. It is also conceivable to adopt a simplified version. And even with such a configuration, it is possible to enjoy the same operation and effect as when the low refractive index material is filled in the concave portion.

When the optical path changing element is constituted by a flat prism, the same operation and effect as those of the above-described negative lens can be obtained. In this case, the prism is provided on the light exit side surface of the light incident side substrate. The cross-sectional shape forms a triangular recess,
The concave portion may be filled with a material having a lower refractive index than that of the light incident side substrate, or a convex portion having a triangular cross section may be formed, and the convex portion may be formed of a material having a higher refractive index than the light incident side substrate. Can be configured to be flattened.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 is a schematic diagram illustrating a structure of a projector according to an embodiment. This projector includes a light source 10, a color separation optical system 50, and a liquid crystal device 6 as a spatial color separation type electro-optical device.
0, and a projection lens 70 serving as a projection optical system, and these are arranged along a virtual illumination optical axis L bent in an L-shape.

A light beam emitted from the light source 10 is separated into a plurality of color lights of red light R, green light G, and blue light B by a color separation optical system 50, and a liquid crystal device 60 responds to image information for each color light. The optical image formed by the light modulation process is formed by the projection lens 70 on the screen 100.
Enlarged projection above. In this embodiment and the following embodiments, the Z-axis direction is the direction of travel of the light beam, the X-axis direction is the direction of 3 o'clock in the direction of travel of the light beam, and the Y-axis direction is the direction of travel of the light beam. A direction at 12:00 (a direction orthogonal to the plane of the paper of FIG. 1) is shown. Here, the illumination optical axis L is substantially parallel to the Z axis.

The light source 10 includes a light source lamp 11 that radiates light rays radially, and a parabolic reflector 12 that reflects light emitted from the light source lamp 11 and emits the light in substantially one direction. The resulting light flux is incident on the color separation optical system 50 as a substantially parallel light flux. Note that an elliptical reflector or a spherical reflector may be used instead of the parabolic reflector 12.

The color separation optical system 50 is, as shown in FIG.
Three dichroic mirrors 50R, 50G, 50 on which different wavelength selection films are formed to selectively reflect or transmit the red light R, the green light G, and the blue light B
B is provided. That is, the dichroic mirror 50
R is a mirror that reflects red light R and transmits green light G and blue light B. The dichroic mirror 50G is a mirror that separates the green light G and the blue light B transmitted through the dichroic mirror 50R, and reflects the green light G and transmits the blue light B. Further, the dichroic mirror 50B is a mirror that reflects the blue light B transmitted through the dichroic mirror 50G. Since only the blue light B reaches the dichroic mirror 50B by the dichroic mirrors 50R and 50G at the preceding stage, a normal total reflection mirror may be used instead of the dichroic mirror 50B.

The three dichroic mirrors 50
R, 50G, and 50B are arranged such that light beams from the light source 10 are incident at different angles on the ZX plane.
Specifically, the angle between the illumination optical axis L of the incident light beam and the normal line of each dichroic mirror 50R, 50G, 50B on the ZX plane is approximately 45 in the dichroic mirror 50G.
Each dichroic mirror 50R, 50G, 50B is arranged so that the dichroic mirror 50R is at 45 + β degrees slightly larger than 45 degrees, and the dichroic mirror 50B is at 45-β degrees slightly smaller than 45 degrees.

The light beam incident along the illumination optical axis L is separated into three color lights R, G, and B by dichroic mirrors 50R, 50G, and 50B. The separated green light G is reflected by the dichroic mirror 50G, bent at right angles to the illumination optical axis L and emitted, and the red light R is reflected by the dichroic mirror 50R and emitted 90+ to the illumination optical axis L.
The blue light B is emitted after being bent at an angle of 2β degrees, reflected by the dichroic mirror 50B and bent at an angle of 90-2β degrees. Accordingly, the red light R has an incident angle of 2β degrees, the green light G has an incident angle of 0 degrees, and the blue light B has an incident angle of −2β degrees with respect to the display surface of the liquid crystal device 60. Becomes

The liquid crystal device 60 is a transmissive liquid crystal device that modulates an incident light beam and emits the modulated light beam from the side opposite to the incident side. The liquid crystal device 60 includes two transparent substrates 611 and 612 such as glass, as shown in FIGS.
Between them, a twisted nematic (TN) liquid crystal 613 serving as an electro-optical element is sealed. A common electrode 614 and a black matrix 615 for shielding unnecessary light are provided on the light incident side substrate 611 disposed on the light incident side.
Etc. are formed and the light emitting side substrate 61 disposed on the light emitting side
2, a pixel electrode 616, a thin film transistor (TFT) 617 as a switching element, and the like are formed.
When a voltage is applied to the pixel electrode 616 via the liquid crystal 17, the liquid crystal 613 sandwiched between the pixel electrode 616 and the common electrode 614 is driven. Note that a plurality of scanning lines 618 and a plurality of data lines 619 are arranged on the light emission side substrate 612 so as to intersect with each other.
In the vicinity of the intersection, the TFT 617 sets the gate to the scanning line 61.
8, the source is the data line 619, and the drain is the pixel electrode 61.
6 and arranged.

Then, a selection voltage is sequentially applied to the scanning lines 618, and the TFs of the horizontal pixels turned on in response to the selection voltages are applied.
The driving voltage of each pixel is written to the pixel electrode 616 via T617. The TFT 617 is turned off by the application of the non-selection voltage, and holds the applied drive voltage in a storage capacitor (not shown). A pixel electrode 616 is provided in a region corresponding to the opening of the liquid crystal device 60 (the opening of the black matrix 615).
Are arranged, and each pixel is composed of a TFT 617 and a pixel electrode 616 (a storage capacitor connected to the pixel electrode as necessary). Note that the liquid crystal 613 can use not only TN but also various types such as a ferroelectric type, an antiferroelectric type, a horizontal alignment type, and a vertical alignment type. Further, in FIG. 3, the pixel electrodes 616 are collectively handled without distinction, but in actuality, as will be described later with reference to FIG. 4, the pixel electrodes 616 include three types of pixel electrodes corresponding to each color light. It is composed of

Further, as shown in FIG.
On the light incident side of No. 11, a microlens array 631 for condensing the respective color lights R, G, B separated by the color separation optical system 50 on the corresponding pixel electrodes 616R, 616G, 616B of the liquid crystal device 60. Is provided. The microlens array 631 includes a plurality of unit microlenses 631A configured in a matrix, a mosaic, or the like. The microlens array 631 is formed on a glass plate by etching or the like, and has a low refractive index resin layer (adhesive) 632 interposed therebetween. Light incident side substrate 61
1 is adhered. The unit microlens 631A (convex portion of the lens) is positioned in the horizontal direction (X-axis direction,
One unit microlens is provided for three pixel electrodes 616R, 616G, and 616B having a pitch corresponding to three times the pixel pitch of the scanning line 618) and corresponding to each color light in the X-axis direction. 631A are formed to correspond. Therefore, the pixel electrode 616G corresponding to the green light G
Of the pixel electrode 616R corresponding to the red light R and the blue light B
The pixel electrode 616B corresponding to the above has an arrangement relationship in which the pixel electrode 616B is located closer to the center from the end by 1/6 of the pitch of the unit microlens 631A in the X-axis direction. Then, as shown in FIG. 3, the light emission side of the light emission side substrate 612 and the microlens array 631
Are provided with polarizing plates 641 and 642, respectively.

Further, a plurality of negative lenses 651 serving as optical path changing elements are provided on the light emitting side surface of the light incident side substrate 611, that is, the surface facing the liquid crystal 613. The negative lens 651 includes a pixel electrode 616R and a pixel electrode 616B.
At the boundary between the pixel electrode 616R and the pixel electrode 616G and between the pixel electrode 616B and the pixel electrode 616G.
The two negative lenses 6 are not arranged at the boundary with 16G.
The portion between 51 is an optical path unchanged area 653. In addition, the relationship with the microlens array 631 is as follows.
The negative lens 651 is arranged such that the boundary between the unit microlenses 631A adjacent to each other in the X-axis direction becomes the optical center of the negative lens 651.

Such a negative lens 651 is a gradient index lens constructed so that the refractive index changes continuously, and is on the light incident side (the side of the micro lens array 631).
For example, the refractive index of the outermost peripheral portion of the negative lens 651 is 1.6, and the refractive index of the intermediate portion is 1.1, so that the refractive index gradually decreases from the side toward the light emission side (the liquid crystal 613 side).
5. The refractive index near the exit surface is set to be 1.4. In the refractive index distribution type lens, the surface on which light is incident and the surface on which light is emitted can be formed in a flat plate shape, so that it is convenient when incorporated in a liquid crystal device as in this embodiment.

The gradient index lens can be manufactured by an ion exchange method or an ion diffusion method. Here, an example of the manufacturing procedure is shown. 1) Light incident side substrate 611 made of soda lime glass material
Wash both sides thoroughly. 2) A Ti film is formed on both surfaces of the light incident side substrate 611 by a sputtering method or the like. 3) Negative lens 651 on Ti film by photolithography
An opening is formed in accordance with the arrangement of. 4) The light incident side substrate 611 is immersed in a molten salt for ion exchange treatment (for example, nitrate containing a monovalent alkali metal such as Tl, K, and Na) to form an ion diffusion region having a lens effect. I do. 5) The Ti film formed on the surface of the light incident side substrate 611 is removed.

Each color light R, which is separated by the color separation optical system 50 and enters the liquid crystal device 60 at a different angle.
G and B are guided by the unit micro lens 631A and the negative lens 651 as follows. The green light G incident on the light incident side substrate 611 at an incident angle of 0 degree is condensed by the unit microlens 631A at a predetermined converging angle ± α degrees near the pixel electrode 616G and subjected to light modulation. Thereafter, the light is emitted from the pixel electrode 616G with a divergence angle of -α to + α degrees.

On the other hand, the red light R incident on the light incident side substrate 611 at an incident angle of + 2β degrees
Since the incident angle of 2β degrees is added to the converging angle of ± α degrees by 31A, the light is condensed near the pixel electrode 616R at a converging angle of −α + 2β degrees to + α + 2β degrees. Similarly, blue light B
Also, the pixel electrode 6 has a converging angle of -α-2β degrees to + α-2β degrees.
Light is collected near 16R. Here, the red light R and the blue light B emitted from the unit microlens 631A are changed in direction of each principal ray by a negative lens 651 disposed in front of the corresponding pixel electrodes 616R and 616B, and the green light G In a state substantially similar to that of the corresponding pixel electrodes 616R, 6
16B. Therefore, by passing through the negative lens 651, the divergence angle (condensing angle) of the red light R becomes −α + 2.
The angle from β degrees to + α + 2β degrees is changed to −α to + α degrees, and the divergence angle (collection angle) of the blue light B is also −α−2β degrees to + α.
The angle from -2 [beta] is-[alpha] to + [alpha], so that the divergence angle of the green light G can be suppressed to the same small angle. The projection lens 70 collects all of the divergent light emitted from the liquid crystal device 60 to form a color projection image, and
Enlarge and project on 00.

According to the present embodiment, the following effects can be obtained. That is, since the negative lens 651 serving as an optical path changing element is provided, the red light R incident on the liquid crystal device 60 in a state where the principal ray is inclined (an angle of ± 2β degrees).
For the blue light B, the inclination of the principal ray thereof is converted to substantially 0 degree by the negative lens 651, and the liquid crystal device is formed at a relatively small angle (strictly, the absolute value of the angle is small) substantially similar to the green light G. Injected from 60. Therefore, it is not necessary to employ a large-diameter lens having a small F value as the projection lens 70, and the cost of the projector can be easily reduced. In particular, the unit micro lens 63 adjacent to the optical center of the negative lens 651
1A, it is possible to bend the light path of the light beam incident from the light condensing element having a specific positional relationship with the light path changing element in substantially only one direction.
The spread angle of the light beam emitted from the pixel including 6R and 616B can be made smaller.

The negative lens 651 is formed only at the position corresponding to the boundary between the adjacent unit microlenses 631A, and the area corresponding to the light path of the green light G becomes the light path unchanged area 653 where no lens is disposed. Therefore, the green light G incident substantially perpendicularly to the liquid crystal device 60 is not affected by the negative lens 651. Therefore, a bright projected image can be realized without using a low-cost projection lens having a large F-number without causing a light loss of the green light G that greatly affects the brightness. In addition, since a small projection lens can be employed, the size of the projector itself can be reduced. Furthermore, since the configuration in which the optical path of the two color lights R and B from different unit microlenses 631A is changed by one negative lens 651 is used, the number of negative lenses 651 provided on the light incident side substrate 611 can be reduced. Accordingly, the production of the negative lens 651 can be facilitated.

The negative lens 6 of the light incident side substrate 611
Since the surface provided with 51 is flattened, the orientation of the liquid crystal 613 in contact with this surface can be improved,
The characteristics of the liquid crystal device 60 can be improved. Further, since the refractive index of the negative lens 651 is configured to change continuously in the thickness direction of the light incident side substrate 611, the direction of the light beam incident on the negative lens 651 is smoothly changed,
The occurrence of light loss due to the interposition of the negative lens 651 can be reduced, and a projector with high light use efficiency can be provided.

The negative lens 651 of this embodiment is a lens having an axially symmetric refractive index distribution.
It is sufficient that the lens has a refractive index distribution in the −Z cross section, and a lens having a cylindrical refractive index distribution having no refractive index distribution in the depth direction of the paper (Y-axis direction) may be used.

Further, since the divergence angle of the red light R and the blue light B emitted from the liquid crystal device 60 can be reduced, if the unit microlenses 631A of the microlens array 631 are short-focused, the color light can be narrowed more narrowly. Since the light is guided to the corresponding pixel, it is possible to further improve the light use efficiency of the liquid crystal device 60 and to prevent color mixing caused by mixing unnecessary color light into the adjacent pixel, thereby providing bright and excellent color reproducibility. Projected image can be realized.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In the following description, the same reference numerals are given to the same parts as the parts or members already described, and the description thereof will be omitted or simplified. In the first embodiment, the negative lens 651 is a lens having a circular shape on the XY plane, and the negative lens 651 is attached to the light incident side substrate 611.
Was made by the ion exchange method.

On the other hand, in this embodiment, as shown in FIG. 5, the light incident side substrate 811 constituting the liquid crystal device 80 is provided.
On the surface facing the liquid crystal 613, there is provided a cylindrical negative lens 851 having an arc-shaped refractive index distribution in the XZ section and not having a refractive index distribution in the depth direction of the paper (Y-axis direction). The points are different.

In the first embodiment, the negative lens 6
51 is configured to bend the optical path of the two types of color light R and B emitted from the two unit microlenses 631A. In contrast, in the present embodiment, two negative lenses 851 are provided at the boundary between the unit microlenses 631A, and the boundary between the two negative lenses 851 is formed in a state corresponding to the boundary between the unit microlenses 631A. I have.

In such a negative lens 851, an arc-shaped concave portion 811A corresponding to the shape of the negative lens 851 is formed on the light incident side substrate 811 so as to extend in the depth direction of FIG. It can be configured by filling a low refractive index material having a lower refractive index than the side substrate 811. Examples of the low refractive index material constituting the negative lens 851 include a heat-resistant resin that can withstand 150 to 200 ° C.
Alternatively, a glass material having a melting point lower than that of the light incident side substrate 811 can be employed, and after filling the light incident side substrate 811 with a low refractive index material, the formation and orientation of the transparent conductive film in the manufacturing process of the liquid crystal device 80 are performed. Detrimental deformation of the low refractive index material due to temperature conditions in each process such as film formation and encapsulation of liquid crystal 613,
The structure is such that no damage occurs. After filling the low refractive index material and before forming the alignment film, the light incident side substrate 81
1 faces the liquid crystal 613 by CMP (Chemical Mechanical).
It is desirable to make the surface flat by cal polishing.

According to the second embodiment, the same effects as those of the first embodiment can be obtained, and the following effects can be obtained. That is, the negative lens 851 serving as an optical path changing element can be provided on the light incident side substrate 811 only by filling the concave portion 811A with a low refractive index material. This eliminates the need for special equipment for performing the exchange method, thereby simplifying the manufacture of the optical path changing element.

Further, since the negative lens 851 is formed in accordance with the color light condensed by each unit microlens 631A, it is not necessary to balance a plurality of color lights when the negative lens 851 is formed. Can be facilitated. In addition, since the negative lens 851 can be formed according to the optical characteristics of the color light, light loss in the negative lens 851 can be reduced, and light use efficiency in the liquid crystal device 80 can be improved. Further, since the negative lens 851 is composed of a cylindrical lens, FIG.
In any part in the depth direction of the drawing, the directions of the principal rays of the color lights R and B can be bent, and uniform optical characteristics can be easily obtained.

The present invention is not limited to the above embodiments, but includes the following modifications. In each of the above embodiments, the negative lens 6 is used as an optical path changing element.
Although 51 and 851 were adopted, the invention is not limited to this.
That is, as shown in FIG. 6, a concave portion 911A having a triangular XZ cross section is formed in the light incident side substrate 911 constituting the liquid crystal device 90, and the concave portion 911A is filled with a low refractive index material. The prism 951 may be employed as an optical path changing element. With such a configuration, the same effects as those described in the above embodiments can be obtained. Note that such a prism 951 can be formed on the light incident side substrate 911 by the same method as that described in the second embodiment.

In the second embodiment, the light path changing element is formed by forming the concave portion 811A in the light incident side substrate 811 and filling the concave portion 811A with a low refractive material. However, the present invention is not limited to this. That is, as in the liquid crystal device 100 shown in FIG. 7, a convex portion 1011A having an arc-shaped cross section is formed on a surface of the light incident side substrate 1011 facing the liquid crystal 613, and this convex portion 1011A is separated from the light incident side substrate 1011. Alternatively, the optical path changing element may be formed by flattening with a material 1051 having a high refractive index. Also, with such an optical path changing element, the same operation and effect as those of the above embodiments can be obtained. The shape of the convex portion is not limited to an arc-shaped cross-section, and the same effect can be obtained by the prism effect even if the cross-sectional shape is triangular.

Further, in the second embodiment, the surface of the light incident side substrate 811 facing the liquid crystal 613 is flattened by CMP, but is not limited to this, and is made of a transparent dielectric material such as SiO or SiO _2. The flattening layer may be formed on a surface of the light incident side substrate facing the liquid crystal element. In each of the embodiments, the plurality of color lights R, G, and B are applied to one liquid crystal device 6.
Although the so-called single-plate type projector modulates at 0, 80, and 90, it is not limited to this. In other words, if the size of the pixel is small and the projector needs to condense the incident light beam with a microlens array or the like and introduce it into the pixel, the projector is configured using a spatial color separation type electro-optical device that handles two color lights. The present invention can be applied to a two-panel projector or a three-panel projector configured using a monochrome electro-optical device. In addition, specific structures, shapes, and the like at the time of carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.

[0051]

According to the present invention, since the light incident side substrate constituting the electro-optical device is provided with the optical path changing element, the light flux introduced into the pixel of the electro-optical device at a predetermined converging angle. The direction of the principal ray is bent by the optical path changing element, and is emitted from the electro-optical device at a substantially vertical angle. Therefore, by reducing the angle of light emitted from the electro-optical device, a bright projection image can be displayed even when a projection optical system having a lens having a relatively large aperture and a large F value is used, and the cost of the projector is reduced. It is easy to reduce the size and size.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a structure of a projector according to a first embodiment of the invention.

FIG. 2 is a schematic diagram illustrating a structure of a color separation optical system according to the embodiment.

FIG. 3 is an exploded perspective view illustrating a structure of the electro-optical device according to the embodiment.

FIG. 4 is a horizontal sectional view of the liquid crystal device according to the embodiment.

FIG. 5 is a horizontal sectional view illustrating a structure of a liquid crystal device included in a projector according to a second embodiment of the invention.

FIG. 6 is a horizontal cross-sectional view illustrating a structure of a liquid crystal device according to a modification of the embodiment.

FIG. 7 is a horizontal sectional view illustrating a structure of a liquid crystal device according to another modification of the embodiment.

FIG. 8 is a schematic diagram of a main part showing a structure of a conventional projector.

FIG. 9 is a cross-sectional view illustrating a structure of an electro-optical device used in a conventional projector.

[Explanation of symbols]

 Reference Signs List 10 light source 50 color separation optical system 60 liquid crystal device (electro-optical device) 612 light emission side substrate 611, 811, 911, 1011 light incidence side substrate 613 liquid crystal (electro-optical element) 631A unit microlens (light-collecting element) 651, 851 Negative lens (light path changing element) 653 Light path unchanged area 811A, 911A Concave part 951 Prism (light path changing element) 1011A Convex part 1051 Light path changing element R, G, B Three types of color light

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/74 H04N 5/74 A 9/31 C 9/31 G02F 1/1335 530 F-term (Reference) 2H088 EA13 EA15 HA03 HA13 HA23 HA24 JA05 JA17 JA20 MA20 2H091 FA05Z FA17Z FA26X FA26Y FA29Z FA35Y FA41Z FD01 HA07 MA07 5C058 EA12 EA13 EA26 EA51 5C060 BA04 BC01 BC05 DA05 GA02 GB06 5G435 AA03 BB03 BB02 DD03 GG08 GG23 GG28 HH02 KK07 LL15

Claims (14)

[Claims] 1. A projector comprising: a light source; and an electro-optical device that modulates a light beam emitted from the light source in accordance with image information, wherein the electro-optical device includes a light incident side substrate and a light emission side substrate. An electro-optical element sandwiched between these substrates; and a plurality of light-condensing elements for condensing a light flux to each pixel of the electro-optical device and causing the light to enter a pixel on the light incident side of the light incident side substrate. However, a plurality of optical path changing elements that bend the optical path of the light beam incident on the electro-optical element are provided on the light exit side surface, and the optical center of each of the plurality of optical path changing elements is the plurality of light condensing elements. Characterized in that the projector corresponds to a boundary portion of the projector. 2. The projector according to claim 1, wherein a light path unchanged area that does not change the light path of the light beam is interposed between the light path changing elements adjacent to each other of the plurality of light path changing elements. Projector. 3. The projector according to claim 2, further comprising a color separation optical system that separates a light beam emitted from the light source into three types of color lights and causes each of the color lights to enter the electro-optical device at different angles. The unaltered optical path region is formed corresponding to a position where only the color light that is incident on the light incident side substrate at a right angle out of the three types of color light separated by the color separation optical system passes. A projector characterized in that: 4. The projector according to claim 1, wherein the optical path changing element has a refractive index interface for refracting a light beam in at least one direction along a surface of the light incident side substrate. A projector characterized in that: 5. The projector according to claim 1, wherein the light path changing element is configured to control one light beam from a plurality of light condensing elements disposed adjacent to one another. A projector, wherein an optical path changing element is arranged so as to correspond thereto. 6. The projector according to claim 1, wherein the light path changing element is constituted by a plurality of optical elements, and one optical path changing element is provided for one light beam from the light collecting element. A projector, wherein the elements are arranged so as to correspond to each other. 7. The projector according to claim 1, wherein a light exit side surface of the light incident side substrate on which the light path changing element is provided is flattened. Projector. 8. The projector according to claim 1, wherein said optical path changing element is constituted by using a negative lens. 9. The projector according to claim 8, wherein the negative lens is configured to continuously change a refractive index in a thickness direction of the light incident side substrate. 10. The projector according to claim 8, wherein the negative lens is provided on a light exit side surface of the light incident side substrate,
A projector comprising: a concave portion having an arc-shaped cross section; and filling the concave portion with a material having a lower refractive index than that of the light incident side substrate. 11. The projector according to claim 8, wherein the negative lens has a convex portion having an arc-shaped cross section on a surface on the light exit side of the light incident side substrate, and A projector characterized in that the surface on which the convex portions are formed is flattened with a material having a higher refractive index than the light incident side substrate. 12. The projector according to claim 1, wherein said optical path changing element is constituted by using a prism. 13. The projector according to claim 12, wherein the prism is provided on a light exit side surface of the light incident side substrate.
A projector characterized in that a concave portion having a triangular cross section is formed, and the concave portion is filled with a material having a lower refractive index than that of the light incident side substrate. 14. The projector according to claim 12, wherein the prism has a projection having a triangular cross section on a light exit side surface of the light incidence side substrate, and the prism has a convex shape. A projector characterized in that the surface on which the portion is formed is flattened with a material having a higher refractive index than the light incident side substrate.