JP2001264727A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the reduction in contrast due to black-floating, and also, to enhance the using efficiency of light emitted from a light source without using a complicated expensive optical element such as a polarization conversion element, in a liquid crystal projector device. SOLUTION: An illumination optical system 2 is provided with a polarizer 7 for transmitting linearly polarized light in one vibration direction among the light emitted from the light source 1 and reflecting linearly polarized light in the other vibration direction, an optical element 8 for reflecting the linearly polarized light reflected by the polarizer 7 in a direction which is nearly equal to the direction of emitting the linearly polarized light transmitted through the polarizer 7, a phase shift element 9 on which the linearly polarized light reflected by the optical element 8 is made incident, a 1st lens array 10 on which the linearly polarized light transmitted through the polarizer 7 and the linearly polarized light emitted from the phase shift element 9 are made incident, and a 2nd lens array 11 which is arranged near the focal position of the lens of the lens array 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device using a liquid crystal panel as a spatial light modulator.

[0002]

2. Description of the Related Art A projection display device which realizes a large screen by magnifying and projecting an image on a screen has been widely used as a large-screen image display device for indoor and outdoor use. This projection display device is mainly classified into a device that projects light emitted from a fluorescent screen of a CRT onto a screen (CRT projector device) and a device that modulates light emitted from a light source with a spatial light modulator and projects the light onto a screen. As for the latter, the mainstream of the latter uses a liquid crystal panel as a spatial light modulator (liquid crystal projector).

FIG. 13 shows a configuration example of an optical system of a conventional liquid crystal projector. Light (non-polarized light) emitted from a light source 51 using a discharge lamp passes through an illumination optical system 52 (microlens arrays 55 and 56 and a condenser lens 57) which is an optical system for guiding the emitted light from the light source to a liquid crystal panel. , TN
(Twisted nematic) Light is incident on a transmission type liquid crystal panel 53 using liquid crystal. In the liquid crystal panel 53, only linearly polarized light in one of the vibration directions of the incident light passes through the liquid crystal layer via the polarizing plate (polarizer) on the surface. The linearly polarized light is modulated by a drive voltage applied to the liquid crystal panel 53 in accordance with the level of the video signal (the vibration direction rotates at a maximum of 90 °), and a polarizing plate (analyzer) on the surface on the opposite side of the liquid crystal panel 53. It is analyzed by. The light transmitted through the liquid crystal panel 53 in this manner is a projection optical system (an optical system for guiding the light emitted from the liquid crystal panel to the screen).
4 is shown on a screen (not shown).

[0004]

The liquid crystal projector has the advantage that a large screen can be realized with a small and light device as compared with the CRT projector, and the light source and the illumination optical system are independent of the liquid crystal panel. There is an advantage that it is easy to increase the luminance by improving them.

[0005] On the other hand, however, the conventional liquid crystal projector apparatus has a drawback that the contrast is low due to the occurrence of black floating and a drawback that the efficiency of using the light emitted from the light source is poor.

The cause of the occurrence of black floating is the pretilt angle (the angle between the alignment film and the liquid crystal molecules) provided on the alignment film on the electrode substrate of the liquid crystal panel. In the liquid crystal panel, even when the vibration direction of the incident linearly polarized light is not rotated (or rotated by 90 °) in the liquid crystal layer, the incident linearly polarized light may become elliptically polarized light due to the presence of the pretilt angle. . When this phenomenon occurs in the low brightness area,
Since the elliptically polarized light partially passes through the analyzer and enters the projection lens, black floating occurs and the contrast is reduced.

In the liquid crystal projector, the angle of incidence of light from the light source on the liquid crystal panel tends to increase by reducing the F number of the illumination optical system in order to display a brighter image. It is known that as the angle of incidence increases, the degree of decrease in contrast due to pretilt becomes more significant. FIG. 14 illustrates the relationship between the degree of reduction in contrast and the angle of incidence on the liquid crystal panel (referred to as “contrast viewing angle characteristics”). Regardless of the incident direction φ of light in the direction parallel to the panel surface of the liquid crystal panel, the contrast CR decreases as the incident angle θ increases. However, the value of the contrast CR for the same value of the incident angle θ differs depending on the incident direction φ, and a line connecting the values of the incident angle θ in which the values of the contrast CR are equal in all the incident directions φ (“equal contrast”) line"
Has a shape approximating an ellipse or rectangle having an aspect ratio of about 1: 2.

On the other hand, the use efficiency of the light emitted from the light source is low because the light emitted from the light source is incident on the liquid crystal panel while being unpolarized. Not to pass through the layers.

On the other hand, recently, by using a polarization conversion element which is an optical element for converting non-polarized light into linearly polarized light, light emitted from a light source is converted into linearly polarized light passing through a polarizer on the surface of a liquid crystal panel. To be done.

FIG. 15 shows an example in which a polarization conversion element is provided in the illumination optical system 52 when the polarizer on the surface of the liquid crystal panel 53 of the liquid crystal projector device of FIG.

The polarization conversion element 61 comprises a plurality of small prisms 62 each of which is formed by a lens 56 of a microlens array 56.
a of the light emitted from the central portion of the lens 56a.
A PBS (polarization beam splitter) surface 62a that transmits polarized light and reflects S-polarized light, and a reflective surface 62b that reflects S-polarized light reflected by the PBS surface 62a toward the condenser lens 57
Are alternately formed. Of the prism 62, the surface from which the S-polarized light reflected by the reflecting surface 62b exits has a 1/2
The wave plate 63 is stuck. A light-shielding plate 64 is attached to a surface of the prism 62 on which light emitted from a peripheral portion of the lens 56a enters.

Of the light emitted from the central portion of each lens 56a, the P-polarized light directly enters the condenser lens 57, and the S-polarized light is reflected by the PBS surface 46a and the PBS surface, and then reflected by the half-wave plate 63. The light is polarized and enters the condenser lens 57. Therefore, light (non-polarized light) emitted from the central portion of each lens 56a is converted into P-polarized light and enters the liquid crystal panel 53.

Although the light emitted from the peripheral portion of each lens 56a is blocked by the light shielding plate 64, it does not enter the liquid crystal panel 53, but the amount of light emitted from the peripheral portion is very small.

As a result, most of the non-polarized light emitted from the light source 1 is converted into P-polarized light and enters the liquid crystal panel 53, so that the efficiency of use of the light emitted from the light source 51 is increased.
A brighter image is displayed on the screen.

However, since this polarization conversion element is manufactured by forming a large number of small prisms on a PBS surface and bonding them together, the configuration is complicated and expensive. Therefore, the use of the polarization conversion element causes an increase in the complexity and cost of the optical system of the liquid crystal projector itself.

SUMMARY OF THE INVENTION In view of the above, the present invention provides a liquid crystal projector device that suppresses a decrease in contrast due to the occurrence of black floating, and that uses a light source without using a complicated and expensive optical element such as a polarization conversion element. The object of the present invention is to increase the efficiency of using the light emitted from the light source.

[0017]

In order to solve this problem, the present applicant has developed a liquid crystal panel that modulates incident light and emits the light, and an illumination optical system that causes light emitted from a light source to enter the liquid crystal panel. In a projection type display device (that is, a liquid crystal projector device) having a projection optical system for guiding the light emitted from the liquid crystal panel to a screen, the illumination optical system includes a linearly polarized light in one of the vibration directions of the light emitted from the light source. And a polarizer that reflects linearly polarized light in the other vibration direction, and converts the linearly polarized light reflected by the polarizer into a direction substantially equal to the output direction of the linearly polarized light that has passed through the polarizer from the polarizer. A reflecting optical element, a phase shifter into which linearly polarized light reflected by the optical element is incident, and a plurality of lenses into which linearly polarized light passing through the polarizer and linearly polarized light emitted from the phase shifter are incident. A first lens array having,
A second lens array having a plurality of lenses and a condensing lens for condensing light emitted from the second lens array, the second lens array being disposed at a substantially focal position of a lens of the first lens array; Suggest something.

In this liquid crystal projector, of the light emitted from the light source, linearly polarized light in one vibration direction passes through the polarizer as it is. On the other hand, of the light emitted from the light source,
The linearly polarized light in the other vibration direction is reflected by the polarizer,
After being reflected by the optical element in a direction substantially equal to the emission direction of the linearly polarized light that has passed through the polarizer, the vibration direction is rotated by the phase shifter (that is, the same vibration direction as the linearly polarized light that has passed through the polarizer). ). As a result, non-polarized light emitted from the light source is converted into light containing a large amount of linearly polarized light component in one vibration direction.

As described above, the combination of only the three optical elements of the polarizer, the optical element for reflecting light, and the phase shifter allows the light emitted from the light source to be converted into light containing a large amount of linearly polarized light component in one vibration direction. Is converted. As a result, the use efficiency of the light emitted from the light source is increased, and a brighter image is displayed on the screen, without increasing the complexity and cost of the optical system as in the case of using a polarization converter, which is a complicated and expensive optical element. Will be displayed.

Further, in this liquid crystal projector, since light is emitted from both the polarizer and the phase shifter, the first lens array is provided in one direction (the direction in which the polarizer and the phase shifter are arranged). A light beam having an expanded cross-sectional shape enters. Accordingly, a light beam having a cross-sectional shape spread in one direction is also incident on the second lens array disposed at a substantially focal position of the lens of the first lens array. A light beam having an expanded cross-sectional shape is emitted.

Here, in an optical system in which two lens arrays and a condenser lens are arranged in this order as in this illumination optical system,
The position of the second lens array is near the pupil position of the optical system (a position slightly closer to the condenser lens than the second lens array is the pupil position). Therefore, in this liquid crystal projector, the second lens array is located near the pupil position of the illumination optical system.

The cross-sectional shape of the light beam passing through the pupil position of the optical system and the angular distribution of the light at the image-forming position include the following: There is a relationship that the angular distribution of the light at the image forming position is similar to the cross-sectional shape.

Therefore, in this liquid crystal projector, a light beam having a cross-sectional shape spread in one direction is emitted from the second lens array located near the pupil position of the illumination optical system, so that the light beam enters the liquid crystal panel (images). The angular distribution of the light
The shape spread in one direction (that is, a shape closer to the equal contrast line of the liquid crystal panel as shown in FIG. 14 than the case where a light beam having a cross-sectional shape as it is from the light source is emitted from the second lens array). become.

As a result, from the contrast viewing angle characteristic of the liquid crystal panel as shown in FIG. 14, the amount of light incident to the liquid crystal panel that has a high degree of lowering the contrast is reduced, and the contrast due to the occurrence of black floating is reduced. Reduction is suppressed.

As an example, the aspect ratio of the cross section of the light beam, which is a combination of the linearly polarized light emitted from the polarizer after passing through the polarizer and the linearly polarized light emitted from the phase shifter, is determined by the equal contrast of the liquid crystal panel. The aspect ratio of the line is made substantially equal, and the aspect ratio of the shape combining all the lenses of the first lens array and the aspect ratio of the shape combining all the lenses of the second lens array are respectively equal to each other. It is preferable that the aspect ratio be substantially equal to the aspect ratio of the contrast line.

As a result, the second lens array located near the pupil position of the illumination optical system emits a light beam having a cross-sectional shape having an aspect ratio substantially equal to the equal contrast line of the liquid crystal panel, and enters the liquid crystal panel. The angular distribution of light has a shape that more closely approximates this isocontrast line. Therefore, a decrease in contrast due to the occurrence of black floating is more effectively suppressed.

It is preferable to use a half-wave plate as the retarder. As a result, of the light emitted from the light source, the linearly polarized light reflected by the polarizer and the optical element becomes linearly polarized light having the same vibration direction as the linearly polarized light that has passed through the polarizer. The light is converted into linearly polarized light having the same vibration direction. Therefore, the utilization efficiency of the light emitted from the light source is further improved, and a brighter image is displayed on the screen.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration example of a liquid crystal projector device according to the present invention. The optical system of this liquid crystal projector device includes a light source 1, an illumination optical system 2, a transmissive liquid crystal panel 3 as a spatial light modulator, and a projection optical system (only the projection lens 4 is shown in the figure). ).

The light source 1 includes a discharge lamp 5 and a discharge lamp 5
And a reflecting mirror 6 for directing the light (non-polarized light) in a certain direction.

The illumination optical system 2 includes a PBS (polarization beam splitter) 7 that transmits P-polarized light and reflects S-polarized light out of the light emitted from the light source 1 at a position closest to the light source 1, and a PB
A reflecting mirror 8 for reflecting the S-polarized light reflected by S7 in the same direction as the emission direction of the P-polarized light from the PBS 7 and a half-wave plate 9 on which the S-polarized light reflected by the reflecting mirror 8 is provided. I have.

The P-polarized light of the light emitted from the light source 1 is P
Pass through BS7 as it is. On the other hand, the S-polarized light of the light emitted from the light source 1 is reflected by the PBS 7 and
After being reflected in the same direction as the emission direction of the P-polarized light from the BS 7, it is converted into P-polarized light by the half-wave plate 9. Thereby, the non-polarized light emitted from the light source 1 is converted into P-polarized light,
Light is emitted in the same direction from S7 and the half-wave plate 9.

As shown in FIG. 2, the arrangement of the reflecting mirror 8 and the half-wave plate 9 with respect to the PBS 7 is such that the P-polarized light emitted from the PBS 7 and the P-polarized light emitted from the half-wave plate 9 are combined. The cross-sectional shape becomes an ellipse having an aspect ratio (approximately 1: 2) substantially equal to the aspect ratio of the iso-contrast line (the shape approximated to an ellipse or a rectangle as shown in FIG. 15) of the liquid crystal panel 3. Has been determined.

As shown in FIG. 1, P of the illumination optical system 2
A micro lens array 10, a micro lens array 11, an optical shutter 12, a condenser lens 13 are located at positions closer to the liquid crystal panel 3 than the BS 7, the reflecting mirror 8 and the half-wave plate 9.
Are provided in order. The P-polarized light emitted from the PBS 7 and the P-polarized light emitted from the half-wave plate 9 enter the microlens array 10.

Each of the micro lens arrays 10 and 11 has a small lens (for example, a diameter of about 1 to 5 mm).
In this figure, a plurality of lenses a and 11a are arranged in an array (in the figure, the individual lenses 10a and 11a are drawn larger than actual ones for convenience).

As shown in FIG. 2, all the lenses 10a,
11a is a rectangle having an aspect ratio of about 1: 2 (an aspect ratio substantially equal to the equal contrast line of the liquid crystal panel 3). Micro lens arrays 10, 11
The direction of the long side of this rectangle is made to coincide with the direction of the long side of the substantially elliptical shape which is a cross section of the light beam obtained by combining the P-polarized light emitted from the PBS 7 and the P-polarized light emitted from the half-wave plate 9. Each is arranged.

The lens 10a of the micro lens array 10
Has a rectangular shape similar to the panel surface of the liquid crystal panel 3 so that the light from the lens 10a is condensed on the panel surface of the liquid crystal panel 3.

The microlens array 11 is disposed at a substantially focal position of the lens 10a of the microlens array 10. The shape of the lens 11a of the microlens array 11 is one-to-one corresponding to the lens 10a, and has a shape in which light from the corresponding lens 10a can be incident as much as possible (in FIG. May be circular).

Here, in an optical system in which two micro lens arrays and a condenser lens are arranged in this order as in the illumination optical system 2, the position of the second micro lens array is near the pupil position of the optical system. (The position slightly closer to the condenser lens than the second micro lens array is the pupil position). Therefore, in this liquid crystal projector, the microlens array 11 is located near the pupil position of the illumination optical system 2.

The cross-sectional shape of the light beam passing through the pupil position of the optical system and the angular distribution of the light beam at the image forming position have an arbitrary cross-sectional shape at the pupil position of the optical system as shown in FIG. When a light beam is passed through (for example, a rectangle or a circle), the angle distribution of the light at the image forming position has a relationship similar to the cross-sectional shape.

The cross-sectional shape of the light emitted from the light source 1 is set to PBS.
7, an aspect ratio of about 1: 2 by the reflecting mirror 8 and the half-wave plate 9
(Aspect ratio approximately equal to the equal contrast line of the liquid crystal panel 3)
And the microlens arrays 10, 1
The shape of the combination of all the lenses 10a and 11a of 1 is a rectangle having an aspect ratio of about 1: 2.
By emitting a light beam having a substantially elliptical cross-sectional shape having an aspect ratio substantially equal to the iso-contrast line of the liquid crystal panel 3 from the microlens array 11 located near the pupil position of FIG. Incident on LCD panel 3 (image formation)
This is to make the angular distribution of the generated light approximate to the contour line of the liquid crystal panel 3.

As shown in FIG. 1, light emitted from each lens 11a of the micro lens array 11 is
2 is incident. The optical shutter 12 is disposed at a pupil position of the illumination optical system 2 (a position slightly closer to the condenser lens 13 than the microlens array 11). FIG. 4 shows a configuration example of the optical shutter 12. As shown in FIG. 1A, the optical shutter 12 includes a transmissive liquid crystal panel (hereinafter, referred to as a “shutter liquid crystal panel”) 21 using TN liquid crystal, and a liquid crystal drive for applying a driving voltage to the shutter liquid crystal panel 21. Circuit 22
It is composed of

The shutter liquid crystal panel 21 has a liquid crystal layer 25 interposed between a transparent fixed pattern electrode group 23 and a transparent common electrode 24. On both surfaces of the shutter liquid crystal panel 21, polarizing plates (polarizers, analyzers) (not shown) that pass only P-polarized light are provided.

As shown in FIG. 4B, the fixed pattern electrode group 23 is composed of ring-shaped fixed pattern electrodes 23b, 23c, 23d and 23e around the fixed pattern electrode 23a.
Are arranged concentrically so as to be in contact with each other.
The shape of each of the fixed pattern electrodes 23a to 23e is substantially the same as the isocontrast line of the liquid crystal panel 3 (an elliptical shape having an aspect ratio of about 1: 2 or a shape approximating a rectangle). The direction of the long side of this shape matches the direction of the long side of the rectangle of the microlens arrays 10 and 11.

The liquid crystal panel for shutter 21 is arranged so that light emitted from the microlens array 11 enters the areas of the fixed pattern electrodes 23a to 23e. The combined area of all the fixed pattern electrodes 23a to 23e is substantially equal to the cross-sectional area of the luminous flux of the incident light. The areas of the fixed pattern electrodes 23a to 23e are substantially equal to each other. A material that blocks light is used in regions around the fixed pattern electrodes 23a to 23e on the panel surface.

The liquid crystal drive circuit 22 is supplied with a control signal from the video signal processing circuit 14 (FIG. 1) based on a video signal Vin supplied from the outside to the liquid crystal projector. FIG. 5 shows a configuration example of the video signal processing circuit 14. The video signal processing circuit 14 detects the peak level.
It comprises a circuit 31, a gain level calculation circuit 32, and a video signal amplitude conversion circuit 33. The peak level detection circuit 31 detects the peak level Vp for each video signal Vin input during one frame time (for example, 1/30 second for an NTSC video signal Vin). This peak level Vp corresponds to the maximum level of the brightness of the image for each frame projected on the screen.

The gain level calculation circuit 32 compares the peak level Vp detected by the peak level detection circuit 31 with the reference level Vmax at each time of one frame. This reference level Vmax is lower than the expected maximum level of the video signal supplied from the outside to the liquid crystal projector device (for example, if the maximum level is set to 100
Is set to about 80). Then, in the gain level calculation circuit 32, when Vp ≧ Vmax, the gain level Gs = 1 is set, and when Vp <Vmax, the gain level Gs = Vp / Vmax (that is, 0 ≦
Gs <1). Therefore, the video signal Vin
Of the video signal Vin, the gain level Gs is 1 in a high-luminance portion (high-luminance frame portion), while the gain level Gs is Vp / Vmax in a low-luminance portion (low-luminance frame portion) of the video signal Vin. become.

The video signal amplitude conversion circuit 33 creates a video signal Vc obtained by converting the entire level of the video signal Vin to 1 / Gs times, which is the reciprocal of the gain level Gs set by the gain level calculation circuit 32. . Therefore, in the high luminance portion of the video signal Vin, the video signal Vc has the same level as the video signal Vin, while in the low luminance portion of the video signal Vin, the video signal Vc has the entire level of the video signal Vin. Vmax / Vp times. This video signal Vc is sent to a liquid crystal drive circuit 15 (FIG. 1) for driving the liquid crystal panel 3.

A signal indicating the gain level Gs set by the gain level calculation circuit 32 of the video signal processing circuit 14 is given to the liquid crystal drive circuit 22 of FIG. 4 as a control signal. In the liquid crystal drive circuit 22, the gain level Gs
The drive voltage is applied to the fixed pattern electrodes 23a to 23e and the common electrode 24 of the liquid crystal panel for shutter 21 in the following cases according to the value of.

(A) When Gs = 1, a drive voltage that allows light to pass through all the fixed pattern electrodes 23a to 23e (that is, a light transmittance of the optical shutter 12 becomes 100%). Is applied. (B) When 0.75 ≦ Gs <1, fixed pattern electrode 2
Light is transmitted through portions 3a to 23d and light is not transmitted through fixed pattern electrode 23e (that is, the light transmittance of optical shutter 12 is 80%).
Apply drive voltage. (C) When 0.5 ≦ Gs <0.75, light is transmitted through the portions of the fixed pattern electrodes 23a to 23c and light is not transmitted through the portions of the fixed pattern electrodes 23d and 23e (that is, the light shutter 12 does not transmit light). 60% light transmittance
Drive voltage is applied. (D) When 0.25 ≦ Gs <0.5, light is transmitted through the fixed pattern electrodes 23a and 23b and light is not transmitted through the fixed pattern electrodes 23c to 23e (that is, the optical shutter 12 does not transmit light). 40% light transmittance
Drive voltage is applied. (E) When 0 <Gs <0.25, fixed pattern electrode 2
In the portion 3a, light is transmitted, and the fixed pattern electrode 23b
No light is transmitted through the portion from 23e to 23e (that is, the light transmittance at the optical shutter 12 becomes 20%).
Apply drive voltage. (F) When Gs = 0, all fixed pattern electrodes 23a
A drive voltage that does not transmit light (that is, the light transmittance at the optical shutter 12 is 0%) is applied to the portion from 23e to 23e.

Therefore, in the optical shutter 12, in the high luminance portion of the video signal Vin, the transmittance of the incident light is 1
On the other hand, in the low luminance portion of the video signal Vin, the incident light is blocked in order from the peripheral portion as shown in FIG. 6 according to the low luminance in the video signal Vin. , 80%, 60%, 40%, 20
% And 0% ((b) to (f) above).

In the high-luminance portion, a light beam having a cross-sectional shape of the outermost fixed pattern electrode 23 e passes through the optical shutter 12. In the low-luminance part, the fixed pattern electrodes 23d, 23c,
A light beam having a cross-sectional shape of the contour shape of 23b or 23a (that is, a light beam whose area is reduced in accordance with low luminance while maintaining a shape substantially equal to the isocontrast line of the liquid crystal panel 3) passes through the optical shutter 12. I do.

As described above, the reason why the optical shutter 12 is arranged at the pupil position of the illumination optical system 2 and the cross-sectional shape of the light beam passing through the optical shutter 12 is substantially equal to the contour line of the liquid crystal panel 3 is as follows. Similarly, by utilizing the relationship between the cross-sectional shape of the light beam at the pupil position shown in FIG. This is for preventing light from being incident on the liquid crystal panel 3 at an incident angle exceeding the angle distribution thereof so as to have a shape substantially equal to the isocontrast line of the panel 3.

The reason why the light flux passing through the optical shutter 12 is reduced in area while maintaining a shape substantially equal to the isocontrast line of the liquid crystal panel 3 in accordance with the low luminance of the video signal Vin is as follows. In the order of incident angles of light having a large degree of lowering the contrast in accordance with the low luminance (for example, in FIG. 15, the order of incident angles of light corresponding to the equal contrast lines of CR = 5, 10, 20,...). This is to prevent the light from entering the liquid crystal panel 3.

As shown in FIG. 1, the light passing through the optical shutter 12 is spatially superimposed by the condenser lens 13 and enters the liquid crystal panel 3. The liquid crystal panel 3 is of an active matrix driving type using TN liquid crystal.
(However, in FIG. 15, the direction of the long side of the isocontrast line (shape approximated to an ellipse or rectangle having an aspect ratio of about 1: 2 in FIG. 15) is the liquid crystal panel. Is different from the direction of the bottom side of, but here, it is assumed that these two directions coincide.)

The liquid crystal panel 3 has a video signal processing circuit 14
A drive voltage corresponding to the level of the video signal Vc created in FIG. 5 is applied from the liquid crystal drive circuit 15. Therefore, in the high luminance portion of the video signal Vin, a drive voltage corresponding to the level of the video signal Vin as it is is applied to the liquid crystal panel 3, while in the low luminance portion of the video signal Vin, the entirety of the video signal Vin is Level of Vmax / V
A driving voltage corresponding to the level increased p times is applied to the liquid crystal panel 3.

In the liquid crystal panel 3, only the P-polarized light of the light incident on the liquid crystal panel 3 passes through the liquid crystal layer via the polarizing plate (polarizer) on the surface. This linearly polarized light is applied to the liquid crystal driving circuit 1
The light is modulated by the drive voltage applied from the liquid crystal panel 5 (the vibration direction rotates at a maximum of 90 °), and is analyzed by a polarizing plate (analyzer) on the surface on the opposite side of the liquid crystal panel 3, whereby the application shown in FIG. The liquid crystal panel 3 transmits through the voltage-transmittance characteristics.

As shown in FIG. 1, light transmitted through the liquid crystal panel 3 is incident on a projection lens 4 and is projected on a screen (not shown).
Is projected to

Next, the operation of the liquid crystal projector will be described. When light is emitted from the light source 1, the emitted light is
It is converted into P-polarized light by the PBS 7, the reflecting mirror 8, and the half-wave plate 9, and has a substantially elliptical cross-sectional shape with an aspect ratio of about 1: 2 (an aspect ratio substantially equal to the iso-contrast line of the liquid crystal panel 3). The light beam is made to enter the microlens array 10.

The light incident on the microlens array 10 is transmitted to the lens 10a of the microlens array 10 (FIG. 2).
And enters the corresponding lens 11a (FIG. 2) of the microlens array 11. Since the combined shape of all the lenses 10a and 11a of the microlens arrays 10 and 11 is a rectangle having an aspect ratio of about 1: 2, the cross-sectional shape of the light beam emitted from the microlens array 11 is also about 1: 1. 2 is almost elliptical.

The light emitted from the microlens array 11 enters the optical shutter 12. Here, the gain level Gs = 1 is set by the video signal processing circuit 14 (FIG. 5) in the high luminance portion of the video signal Vin supplied from the outside to the liquid crystal projector device. Is not interrupted at all. Therefore, the cross-sectional shape of the light beam passing through the optical shutter 12 is determined by the outermost fixed pattern electrode 23 of the shutter liquid crystal panel 21 (FIG. 4).
e.

As a result, as shown in FIG. 7A, light is applied to the liquid crystal panel 3 with an angular distribution similar to the contour shape of the fixed pattern electrode 23e (ie, an angular distribution substantially equal to the isocontrast line of the liquid crystal panel 3). Is incident.

Since the gain level Gs = 1 in the high luminance portion, the video signal processing circuit 14 generates the video signal Vc at the level of the video signal Vin as it is.
Therefore, the liquid crystal panel 3 applies a drive voltage corresponding to the level of the video signal Vin as it is (a drive voltage corresponding to a high transmittance in the applied voltage-transmittance characteristic as shown in FIG. 14).
Is applied from the liquid crystal drive circuit 15.

On the other hand, in the low luminance portion of the video signal Vin, the video signal processing circuit 14
Since s = Vp / Vmax, the optical shutter 12
The cross-sectional shape of the light beam passing through the fixed pattern electrode 2 of the shutter liquid crystal panel 21 (FIG. 4) depends on the brightness.
The contour shape of 3d, 23c, 23b or 23a (a shape in which the area is reduced while maintaining a shape substantially equal to the isocontrast line of the liquid crystal panel 3) is obtained.

As a result, as shown in FIG. 7B, the liquid crystal panel 3 has an angular distribution similar to the contour shape of the fixed pattern electrodes 23d, 23c, 23b or 23a (ie, substantially equal to the contour line of the liquid crystal panel 3). Light enters the liquid crystal panel 3 in the order of light having an angle distribution of the shape and an angle of incidence with a high degree of decreasing the contrast. As a result, in accordance with the low luminance, the light having an incident angle with a high degree of decreasing the contrast is not incident on the liquid crystal panel 3 (that is, is not projected on the screen).

In the low luminance portion, since the gain level Gs = Vp / Vmax, the video signal processing circuit 14
Thus, a video signal Vc in which the entire level of the video signal Vin is increased by a factor of Vmax / Vp is created. Therefore,
The liquid crystal panel 3 applies a drive voltage (also a drive voltage corresponding to a high transmittance in an applied voltage-transmittance characteristic as shown in FIG. 14) according to the level increased by Vmax / Vp times to the liquid crystal drive circuit 15. Is applied. as a result,
Again, the transmittance of the liquid crystal panel 3 increases.

As described above, in this liquid crystal projector, the light emitted from the light source 1 is converted into P-polarized light by a combination of only the three optical elements of the PBS 7, the reflecting mirror 8, and the half-wave plate 9. Therefore, for example, as compared with a case where the configuration such as a polarization conversion element is complicated and the light emitted from the light source 1 is converted into P-polarized light using an expensive optical element, the optical system becomes complicated and the cost is increased. Without
The use efficiency of the light emitted from the light source 1 is increased, and a brighter image is displayed on the screen.

Moreover, in this liquid crystal projector,
In the low-luminance portion of the video signal Vin, the light is blocked by the optical shutter 12 in the order of decreasing contrast, so that the light is not projected on the screen and the transmittance of the liquid crystal panel 3 is increased.

As a result, even in the low-luminance portion, the range where the change of the transmittance with respect to the change of the applied voltage in the applied voltage-transmittance characteristic of the liquid crystal panel 3 is gradual is utilized.
The luminance can be finely adjusted (that is, the gradation expression in the low luminance portion is improved).

In the low-luminance portion of the video signal Vin, the light emitted from the microlens array 11 is illuminated by the illumination optics in the order of decreasing contrast according to the viewing angle characteristics of the liquid crystal panel 3. The light is blocked by the optical shutter 12 located at the pupil position of the system 2.

As a result, in the low-brightness portion, light having a high degree of lowering the contrast is not incident on the liquid crystal panel 3 (that is, is not projected on the screen), so that a decrease in contrast due to the occurrence of black floating is suppressed. ing.

Further, since the optical shutter 12 is arranged at the pupil position of the illumination optical system 2, the light is transmitted so as to pass light having a cross section substantially equal to the isocontrast line of the liquid crystal panel 3 as shown in FIG. By configuring the shutter 12, it is easy to block the light with the optical shutter 12 in the order of decreasing contrast.

The brightness of the image projected on the screen from the liquid crystal panel 3 via the projection lens 4 is the product of the light transmittance of the optical shutter 12 and the rate of increase of the level of the video signal Vc with respect to the video signal Vin. In the low-brightness portion, an amount of light corresponding to the value of Vp / Vmax passes through the optical shutter 12, and the level of the video signal Vc becomes Vmax / Vp times the level of the video signal Vin. In addition, the brightness of the image projected on the screen is suppressed from deviating from the brightness when the light shutter 12 does not block light at all and the level of the video signal Vc is the same as that of the video signal Vin.

That is, when the values of the gain levels Gs are exactly 0.8, 0.6, 0.4, and 0.2, the light passes through the optical shutter as shown in (b) to (e) above. The rate will be 80%, 60%, 40%, 20%,
The level of the video signal Vc is 1 / 0.8, 1/0.
By increasing the ratio by 6,1 / 0.4,1 / 0.2, the ratio of the passage rate × the increase rate of the level = 1, the brightness of the image projected on the screen is reduced by the optical shutter 12. No interruption is made and the level of the video signal Vc is
It is the same as when it is the same as in. Further, even when the gain level Gs takes any other value, the rate of increase of the “passage rate × level” does not largely deviate from 1, so that the brightness of the image projected on the screen is reduced by the optical shutter 12.
, Light is not blocked at all, and deviation from the brightness when the level of the video signal Vc is the same as that of the video signal Vin is suppressed.

Further, as shown in FIG. 4, since the optical shutter 12 is configured to block light with the liquid crystal panel,
The high-speed operation of the optical shutter 12 is possible as compared with a case where light is blocked by a mechanically operated component. Therefore, in response to a change in the level of the video signal Vin, it is possible to switch between whether or not to block light and the amount of light to be blocked.

Further, as the shutter liquid crystal panel,
Since a liquid crystal panel having a plurality of concentric fixed pattern electrodes is used, the structure and control of the optical shutter 12 are simplified.

In this liquid crystal projector, P
The cross-sectional shape of the light beam obtained by combining the P-polarized light emitted from the BS 7 and the P-polarized light emitted from the half-wave plate 9 has an aspect ratio of 1: 2.
(Aspect ratio approximately equal to the equal contrast line of the liquid crystal panel 3)
And the microlens arrays 10, 1
By combining the shape of all the lenses 10a and 11a into a rectangle having an aspect ratio of 1: 2, the microlens array 11 located near the pupil position of the illumination optical system 2 can be used.
A light beam having a substantially elliptical cross-sectional shape with an aspect ratio of about 1: 2 (that is, a shape approximating the isocontrast line of the liquid crystal panel 3) is emitted.

As described above, the cross-sectional shape of the light emitted from the microlens array 11 is close to the contour line of the liquid crystal panel 3, and the cross-sectional shape of the light passing through the optical shutter 12 is substantially the same as the contour line. Since all of the fixed pattern electrodes 2 of the optical shutter 12 are equal,
When light is transmitted through the portions 3a to 23e (in the case of (a) described above), almost all of the light emitted from the microlens array 11 passes through the optical shutter 12. Therefore, from this point as well, the light use efficiency is increased, and a bright image is displayed on the screen.

In the above example, the description has been made on the assumption that the direction of the long side of the isocontrast line of the liquid crystal panel 3 coincides with the direction of the bottom side of the liquid crystal panel 3. On the other hand, when the two directions are different, it is necessary to change the shape of the microlens arrays 10 and 11 and change the arrangement of the liquid crystal panel 3.

FIG. 8 shows the shapes of the micro lens arrays 10 and 11 in this case. This micro lens array 1
At 0 and 11, the lenses 10a and 11a are arranged obliquely with respect to the bases 10b and 11b of the microlens arrays 10 and 11, respectively.
The shape obtained by adding 1a is a substantially rectangular shape having an aspect ratio of about 1: 2 (an aspect ratio substantially equal to the equal contrast line of the liquid crystal panel 3). The angle in the arrangement direction of the lenses 10a and 11a with respect to the directions of the bases 10b and 11b is equal to the angle in the direction of the long side of the equal contrast line of the liquid crystal panel 3 with respect to the direction of the base of the liquid crystal panel 3.
(Even though the individual lenses 10a and 11a are drawn large for convenience in the drawing, since the individual lenses 10a and 11a are actually considerably smaller than this, all the lenses 10a and 11a
It is easy to make the shape obtained by combining them into a substantially rectangular shape. Also in this case, the shape of the lens 11a may be circular as well. )

FIG. 9 shows an arrangement example of the liquid crystal panel 3 in this case. The liquid crystal panel 3 is arranged with the base 3a inclined on a plane parallel to the panel surface such that the direction of the long side of the isocontrast line coincides with the direction of the long side of the cross-sectional shape of the light beam passing through the optical shutter 12. Have been.

The microlens arrays 10 and 11 are formed as shown in FIG. 8 and the liquid crystal panel 3 is arranged as shown in FIG. Even when the direction is different from the direction of the bottom side, the angle distribution of the incident light on the liquid crystal panel 3 becomes substantially equal to the isocontrast line of the liquid crystal panel 3 and the light from the lens 10a of the microlens array 10 is The light is condensed at 3.

Further, in the above example, the light emitted from the microlens array 11 is controlled by the liquid crystal drive circuit 15 in the low luminance portion of the video signal Vin, and the light emitted from the microlens array 11 in the order of light having a large degree of lowering the contrast. In addition to blocking at 12, the transmittance of the liquid crystal panel 3 is increased. However, as another example, the optical shutter 12 and the liquid crystal drive circuit 15 may not be provided.

FIG. 10 shows an example of the configuration of a liquid crystal projector in which the optical shutter 12 and the liquid crystal drive circuit 15 are not provided. The same reference numerals are given to the parts common to FIG. ing.

In this liquid crystal projector, a video signal Vin supplied from the outside is directly sent to the liquid crystal drive circuit 15, and a drive voltage corresponding to the level of the video signal Vin is applied from the liquid crystal drive circuit 15 to the liquid crystal panel 3. Is done.

In the illumination optical system 16 of the liquid crystal projector, a light beam having a substantially elliptical cross-sectional shape and having an aspect ratio of about 1: 2 emitted from the microlens array 11 directly enters the condenser lens 13. As a result, as shown in FIG. 7C, the angular distribution of the light incident on the liquid crystal panel 3 becomes a substantially elliptical shape having an aspect ratio substantially equal to the isocontrast line of the liquid crystal panel 3. Therefore, even in this liquid crystal projector, FIG.
Since the amount of light incident on the liquid crystal panel, which also greatly reduces the contrast, is reduced from the contrast viewing angle characteristics of the liquid crystal panel as shown in (1), the decrease in contrast due to the occurrence of black floating is suppressed.

In the above example, the cross-sectional shape of the light emitted from the light source 1 is approximately 1: 2 (approximately equal to the iso-contrast line of the liquid crystal panel 3) by the PBS 7, the reflecting mirror 8 and the half-wave plate 9. By making the shape of the microlens array 11 into a substantially elliptical shape and by combining all the lenses 10a and 11a of the microlens arrays 10 and 11 into a rectangle having an aspect ratio of about 1: 2, A light beam having a substantially elliptical cross-sectional shape with an aspect ratio substantially equal to the isocontrast line of the panel 3 is emitted. However, the present invention is not limited to this.
The BS 7, the reflecting mirror 8 and the half-wave plate 9 do not need to be formed into an almost elliptical shape having an aspect ratio substantially equal to the equal contrast line of the liquid crystal panel 3, and the combined shape of the lenses 10 a and 11 a is not so strict. It is not necessary to form a rectangle having an aspect ratio substantially equal to the isocontrast line.

Also in this case, since light is emitted from both the PBS 7 and the half-wave plate 9, the micro-lens array 10 has one direction (the direction in which the PBS 7 and the half-wave plate 9 are arranged). A light beam having an expanded cross-sectional shape enters. Therefore, since the light beam having the cross-sectional shape expanded in one direction is incident from the microlens array 10 to the microlens array 11, the light beam having the cross-sectional shape expanded in one direction is also emitted from the microlens array 11. As a result, the angle distribution of the light incident on the liquid crystal panel 3 also has a shape spread in one direction (that is, a light beam having a cross-sectional shape of the light emitted from the light source 1 as it is from the microlens array 11), as shown in FIG. (A shape close to the equi-contrast line of the liquid crystal panel 3).

Thus, from the contrast viewing angle characteristic of the liquid crystal panel as shown in FIG. 14, the amount of incident light to the liquid crystal panel, which also greatly reduces the contrast, is reduced. Is suppressed.

In the above example, the light emitted from the light source 1 is separated into P-polarized light and S-polarized light by using the PBS 7, but the PB that transmits the P-polarized light and reflects the S-polarized light is used.
The light emitted from the light source 1 may be separated into P-polarized light and S-polarized light using a polarizer other than S (for example, a polarizing plate).

In the above example, the PBS 7 and the reflecting mirror 8 are used.
Is incident on the half-wave plate 9, but the S-polarized light is rotated by an angle other than 90 degrees in the phase shifter other than the half-wave plate (that is, the oscillation direction of the linearly polarized light is rotated by an angle other than 90 degrees). ). Also in this case, the s-polarized light is rotated in the oscillation direction by the phase shifter (that is, the s-polarized light includes the p-polarized component). Is converted. Therefore, the utilization efficiency of the light emitted from the light source is also increased, and a brighter image is displayed on the screen.

In the above example, the video signal processing circuit 1
4, the peak level of the video signal Vin supplied from the outside to the liquid crystal projector is detected, and when this peak level is smaller than the reference level, the optical shutter 12
And the liquid crystal panel 3 is driven by increasing the level Vin of the video signal. However, as another example, as shown in FIG. 11, based on the operation of lowering the luminance with the luminance adjustment button 41 of the liquid crystal projector device, the gain level Gs (0
.Ltoreq.Gs.ltoreq.1), and a gain level calculating circuit 42 is provided according to the value of the gain level Gs.
Light may be blocked by the optical shutter 12 as shown in FIG.

Thus, when the brightness adjustment button 41 is operated to lower the brightness, the liquid crystal panel
Voltage (liquid crystal driving circuit 15) so that the transmittance of
Instead of changing the driving voltage applied to the liquid crystal panel 3), the light is not projected on the screen in the order of light having a high degree of decreasing the contrast in accordance with the operation amount. Therefore, it is possible to finely adjust the luminance by using the range of the change of the transmittance with respect to the change of the applied voltage in the applied voltage-transmittance characteristic characteristic of FIG. Has been improved), and
A decrease in contrast due to the occurrence of black floating is suppressed.

In the above example, the number of fixed pattern electrodes of the shutter liquid crystal panel 21 is five. However, the number of fixed pattern electrodes may be three or four, or six or more. It may be. When the number of the fixed pattern electrodes is set to six or more, the brightness of the image projected on the screen does not block light at all by the optical shutter 12 and the level of the video signal Vc is changed to the video signal Vin.
Deviation from the brightness in the case of the same as described above is further suppressed.

In the above example, the optical shutter 12 is configured to block light with a liquid crystal panel using a TN liquid crystal. As another example, a polymer dispersed liquid crystal (PDLC) is used.
Shutter 1 so as to block light with a liquid crystal panel using
2 may be configured.

The polymer-dispersed liquid crystal is opaque when no driving voltage is applied, and changes to transparent when a driving voltage is applied. When the drive voltage is not applied, as shown in FIG. 12, the light incident on the polymer dispersed liquid crystal 43 is diffused from the polymer dispersed liquid crystal 43 and emitted. Therefore, the condensing lens 1 shown in FIG.
Since the ratio of the light incident on the liquid crystal panel 3 decreases, the liquid crystal panel 3
The amount of light incident on the optical shutter 12 decreases (that is, the light transmittance of the optical shutter 12 decreases). On the other hand, when driving voltage is applied,
Since the light emitted from the polymer dispersed liquid crystal 43 is not diffused, the amount of light incident on the liquid crystal panel 3 does not decrease.

The liquid crystal panel using the polymer dispersed liquid crystal does not require a polarizer or an analyzer, unlike the liquid crystal panel using a TN liquid crystal. Therefore, if the optical shutter 12 is constituted by a liquid crystal panel using a polymer dispersed liquid crystal, light is not absorbed by the polarizer or the analyzer, and a brighter image is displayed on the screen.

Alternatively, the optical shutter 12 may be configured so as to block light other than the liquid crystal panel. In particular, when light is blocked by the optical shutter 12 in response to the operation of the brightness adjustment button 41 as in the example of FIG. 11, the optical shutter 12 does not require much high-speed operation. The optical shutter 12 may be configured to block light.

Further, in the above example, the optical shutter 12 is arranged at the pupil position of the illumination optical system 2, but instead of the pupil position of the illumination optical system 2, the optical shutter is moved toward the pupil position of the projection optical system. 12 may be arranged. Even in such a case, of the light incident on the liquid crystal panel 3, the light having an incident angle exceeding the angular distribution substantially similar to the cross-sectional shape of the light passing through the optical shutter 12 is not affected by the light emitted from the liquid crystal panel 3. Since the light does not pass through the shutter 12 (therefore, the light is not projected on the screen), similarly to the case where the optical shutter 12 is arranged at the pupil position of the illumination optical system 2, a decrease in contrast due to the occurrence of black floating is suppressed. However, arranging the optical shutter 12 at the pupil position of the illumination optical system 2 reduces the amount of light incident on the liquid crystal panel 3, so that the liquid crystal panel 3 can be prevented from being heated by light.

Alternatively, an optical shutter that blocks light in order of decreasing degree of contrast according to the contrast viewing angle characteristic of the liquid crystal panel 3 at a position other than the pupil position in the illumination optical system 2 or the projection optical system. May be provided.

Further, in the above example, the optical shutter that blocks light in order of decreasing contrast is provided according to the contrast viewing angle characteristic of the liquid crystal panel 3, but the incident angle to the liquid crystal panel is large. An optical shutter that blocks light in order may be provided. For example, in order to block light in order of increasing incident angle in an optical shutter that blocks light in a liquid crystal panel in which a plurality of fixed pattern electrodes are concentrically arranged like the optical shutter 12, the shape of the fixed pattern electrode may be circular. Good. Even in such a case, when the light is blocked by the optical shutter, light having a large degree of decreasing the contrast is blocked more than light having a small degree of decreasing the contrast from the contrast viewing angle characteristic as shown in FIG. Become so. Therefore, the amount of light projected on the screen with a large degree of lowering the contrast is reduced more than the amount of light projected on the screen with a small degree of lowering the contrast. Is suppressed.

In the above example, the video signal processing circuit 14 detects the peak level Vp of the video signal Vin and compares it with the reference level Vp every time for one frame.
The video signal processing circuit 14 is provided at predetermined time intervals other than for one frame.
The detection and the comparison may be performed by using.

In the above example, the present invention is applied to a single-panel transmissive liquid crystal projector, but a three-panel transmissive liquid crystal projector, a single-panel reflective liquid crystal projector, and a three-panel reflective liquid crystal projector are used. The present invention may be applied to a projector device.

Further, the present invention is not limited to the above-described example, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0104]

As described above, according to the projection type display apparatus of the present invention, the light emitted from the light source is obtained by combining only three optical elements, ie, a polarizer, an optical element for reflecting light, and a phase shifter. The linearly polarized light in one of the vibration directions increases, so that the light emitted from the light source does not become complicated and costly as in the case of using a polarization conversion element which is a complicated and expensive optical element. The effect is that the use efficiency of the image can be enhanced and a brighter image can be displayed on the screen.

Then, the luminous flux having a cross-sectional shape spread in one direction is emitted from the second lens array located near the pupil position of the illumination optical system, and the angular distribution of the light entering the liquid crystal panel is reduced. Since the shape is close to the isocontrast line, the effect of suppressing a decrease in contrast due to the occurrence of black floating can be obtained.

Note that the aspect ratio of the cross section of the light beam obtained by combining the linearly polarized light emitted from the polarizer after passing through the polarizer and the linearly polarized light emitted from the phase shifter is substantially equal to the aspect ratio of the isocontrast line of the liquid crystal panel. Equal, the aspect ratio of the shape combining all the lenses of the first lens array, and the aspect ratio of the shape combining all the lenses of the second lens array,
If the aspect ratio of each of the isocontrast lines is substantially equal to each other, the angular distribution of light incident on the liquid crystal panel becomes a shape that more closely approximates the isocontrast lines, so that the lowering of the contrast due to the occurrence of black floating is better. The effect of being able to suppress is obtained.

If a half-wave plate is used as the phase shifter, all the light emitted from the light source is converted into linearly polarized light having the same vibration direction, so that the efficiency of use of the light emitted from the light source is further improved. Thus, an effect that a brighter image can be displayed on the screen can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a liquid crystal projector device of the present invention.

FIG. 2 is a diagram showing transmitted light of a PBS in FIG. 1, emitted light of a half-wave plate 9, and the shape and arrangement of a microlens array in FIG.

FIG. 3 is a diagram illustrating a relationship between a cross-sectional shape of a light beam passing through a pupil position of an optical system and an angular distribution of the light beam at an image forming position.

FIG. 4 is a diagram illustrating a configuration example of an optical shutter in FIG. 1;

FIG. 5 is a diagram illustrating a configuration example of a video signal processing circuit in FIG. 1;

FIG. 6 is a diagram showing how incident light is blocked by the optical shutter shown in FIG. 1;

FIG. 7 is a diagram showing an angle distribution of light incident on the liquid crystal panel of FIG. 1;

FIG. 8 is a diagram showing a modification of the microlens array of FIG. 1;

FIG. 9 is a diagram showing a modified example of the arrangement of the liquid crystal panel of FIG. 1;

FIG. 10 is a diagram showing another configuration example of the liquid crystal projector device of the present invention.

FIG. 11 is a diagram showing another configuration example of the liquid crystal projector device of the present invention.

FIG. 12 is a diagram showing light emitted from a polymer-dispersed liquid crystal when no voltage is applied.

FIG. 13 is an example showing a configuration example of an optical system of a conventional liquid crystal projector device.

FIG. 14 is a diagram illustrating contrast viewing angle characteristics of a liquid crystal panel.

FIG. 15 is a diagram illustrating a configuration example of a conventional polarization conversion element.

[Explanation of symbols]

1 light source, 2 illumination optical system, 3 liquid crystal panel, 3
a bottom of liquid crystal panel, 4 projection lens, 5 discharge lamp, 6,8 reflector, 7 PBS (polarizing beam splitter), 9 1/2 wavelength plate, 10,11 micro lens array, 10a, 11a micro lens array lens , 12 optical shutter, 13 condenser lens, 14 video signal processing circuit, 15, 22 liquid crystal drive circuit, 21 liquid crystal panel for shutter, 23
Fixed pattern electrode group, 23a to 23e fixed pattern electrode, 24 common electrode, 25 liquid crystal layer, 31
Peak level detection circuit, 32, 42 gain level calculation circuit, 33 video signal amplitude conversion circuit, 41 brightness adjustment button, 43 polymer dispersed liquid crystal

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) G09F 9/00 360 G02F 1/1335 530 F term (Reference) 2H088 EA16 HA14 HA15 HA18 HA21 HA23 HA24 HA28 MA02 MA06 2H091 FA08X FA10X FA11X FA14Z FA21X FA26X FA29X FA34X FA41X LA15 LA17 LA18 MA07 5G435 AA00 AA03 BB12 BB15 BB17 CC09 DD04 EE25 FF03 FF05 FF07 FF12 FF15 GG02 GG23 GG28 GG46 LL15

Claims (3)

[Claims] 1. A liquid crystal panel that modulates and emits incident light, an illumination optical system that causes light emitted from a light source to enter the liquid crystal panel, and a projection optical system that guides light emitted from the liquid crystal panel to a screen. A projection type display device, comprising: a polarizer that allows the illumination optical system to pass linear polarized light in one vibration direction of reflected light from the light source and reflects linear polarized light in the other vibration direction; and the polarizer. An optical element that reflects the linearly polarized light reflected by the polarizer in a direction substantially equal to the emission direction of the linearly polarized light that has passed through the polarizer from the polarizer; and a phase shift in which the linearly polarized light reflected by the optical element is incident. A first lens having a plurality of lenses into which linearly polarized light passing through the polarizer and linearly polarized light emitted from the phase shifter are incident;
A second lens array having a plurality of lenses disposed substantially at a focal position of a lens of the first lens array; and a condenser for condensing light emitted from the second lens array. A projection display device comprising a lens. 2. The projection display device according to claim 1, wherein a cross section of a light beam obtained by combining linearly polarized light emitted from the polarizer through the polarizer and linearly polarized light emitted from the phase shifter is formed. An aspect ratio is substantially equal to an aspect ratio of an iso-contrast line of the liquid crystal panel. An aspect ratio of a shape obtained by combining all the lenses of the first lens array, and all the lenses of the second lens array Wherein the aspect ratio of the combined shape is substantially equal to the aspect ratio of the equal contrast line of the liquid crystal panel. 3. The projection display device according to claim 1, wherein the retarder is a half-wave plate.