JP2002082386A - Projection-type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection-type display device, with which the color mixture of an image caused in the case that the light emitting part of a light source is increased during use, is prevented and the image of colors which are bright and are originally desired to be displayed is displayed in the projection type display device of a color sequence system. SOLUTION: In the projection type display device, provided with a discharge lamp 10, an elliptic surface mirror 11 to condense white light radiated from the discharge lamp 100 on a color wheel 103, a color wheel 15 obtained by combining the color filters of red, green and blue in a disk-like shape and to selectively transmit the light beams of red, green and blue bands from the incident light by making a condensing lens 18 to rotate efficiently condense the transmitted light of the color wheel 15 and to irradiate to a liquid crystal panel 20, the liquid crystal panel 20 to form an optical image, in accordance with a video signal received and a projection lens 22 to enlarge and project the optical image formed on the liquid crystal panel 20 on a screen (not shown), a light-shielding diaphragm 13 to partially shield the transmitted light of the color wheel 15 is provided, and the size of a condensing spot 14 formed on the color wheel 15 is limited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial light modulator and a projection lens, which are illuminated by light radiated from a light source and are simultaneously supplied with a video signal from the outside to form an optical image. The present invention relates to a projection display device that performs enlarged projection on a screen.

[0002]

2. Description of the Related Art Hitherto, as a video device for a large screen, there has been known a projection display device using various spatial light modulators. These include, for example, using a transmissive or reflective liquid crystal panel as a spatial light modulator, illuminating the liquid crystal panel with a light source, and forming an optical image on the liquid crystal panel in accordance with a video signal supplied from the outside. The optical image formed thereon is enlarged and projected on a screen by a projection lens.

[0003] In recent years, as the need for higher luminance has increased, a three-panel projection display device using three spatial light modulators such as a liquid crystal panel has become mainstream. However, there is a problem that the cost of the entire apparatus increases.

On the other hand, there is known a single-panel projection display device disclosed in, for example, JP-A-59-230383, in which the cost is reduced by using only one liquid crystal panel. However, such a projection display device has a problem in that the resolution is substantially reduced because it is necessary to provide three primary color filters for each pixel on the liquid crystal panel. In addition, there is a problem that the luminance of the screen is reduced because about 2/3 of the illumination light is lost in the color filter.

On the other hand, there is known a color-sequential projection display apparatus using a disk-shaped color wheel. In this method, one spatial light modulation element is sequentially irradiated with red, green, and blue primary color lights to perform full color display.

FIG. 13 is a diagram showing a configuration example of a conventional projection display device. The ellipsoidal mirror 101 focuses white light emitted from the discharge lamp 100 on the color wheel 103. The UV-IR cut filter 102 is the discharge lamp 1
Remove ultraviolet and infrared light from 00 radiation. The color wheel 103 is a combination of fan-shaped color filters of red, green, and blue in a disk shape, and selectively rotates light in the red, green, and blue bands from light incident from the discharge lamp 100 by rotating. Can be transmitted. The condenser lens 104 efficiently condenses the light transmitted through the color wheel 103 and irradiates the liquid crystal panel 106. Field lens 1
Reference numeral 05 denotes a projection lens 1 for transmitting light transmitted through the liquid crystal panel 106.
07.

Light emitted from the discharge lamp 100 is applied to the liquid crystal panel 106 via the color wheel 103, the condenser lens 104, and the field lens 105, and the color wheel 103 is rotated in synchronization with the image display on the liquid crystal panel 106. On the liquid crystal panel 106, optical images corresponding to red, green, and blue video signals are formed in a time-division manner. By enlarging and projecting the optical image on the liquid crystal panel 106 onto a screen (not shown) by the projection lens 107, a large screen image of full color display can be obtained.

According to this method, one liquid crystal panel requires three liquid crystal panels.
A high-resolution color image equivalent to the plate type is obtained. Also,
Since it is not necessary to provide a fine color filter for each pixel on the liquid crystal panel, the yield of the liquid crystal panel is improved,
The cost of the apparatus can be reduced.

[0009]

The projection type display device shown in FIG. 13 realizes a resolution equivalent to that of the three-panel system with one spatial light modulation element, and enables a reduction in cost and size of the device. However, there are the following problems. FIG.
, The discharge lamp 10 is placed on the color wheel 103.
A condensed spot 108 is formed by the zero emitted light. The size of the converging spot 108 depends on the size of the light emitting portion 100a of the discharge lamp 100, and the larger the light emitting portion 100a, the larger the condensing spot 108.

FIG. 14 is a diagram for explaining the relationship between the color wheel 103 and the converging spot 108. The color wheel 103 is configured by combining, for example, red, green, and blue fan-shaped color filters 103R, 103G, and 103B in a disk shape, and rotates in synchronization with the display of the liquid crystal panel 106 to perform full-color display. Will be possible. However, when the condensed spot 108 extends between two adjacent color filters, light transmitted through the two color filters is simultaneously incident on the liquid crystal panel, causing color mixing, and a color different from the color originally desired to be displayed. There is a problem that an image is displayed on a screen.

In practice, each of the color filters 103R, 1R,
03G, 103B boundaries 103RG, 103GB, 10
During the period when the 3BR passes through the condensing spot 108, the above-described color mixing problem is solved by setting the liquid crystal panel 106 to a black display, that is, in an OFF state (hereinafter, the liquid crystal panel 10 is referred to as a liquid crystal panel 10).
6 is referred to as a black display period).

However, it is known that the size of the light emitting portion 100a (hereinafter, referred to as arc length) of a light source used in a projection display device such as the discharge lamp 100 changes during use. The arc length tends to be longer according to the lighting time of the discharge lamp 100. Accordingly, during the life of the discharge lamp 100, the converging spot 108 on the color wheel 103 gradually increases, and the converging spot 108
May extend over the black display period of the liquid crystal panel 106 over the two adjacent color filters. In this case, it is not possible to prevent a mixed color optical image from being formed on the liquid crystal panel 106 during the initially set black display period, and an image of a color different from the color originally desired to be displayed is displayed on the screen.

As the arc length of the discharge lamp 100 changes, the condensed spot 10 formed on the color wheel 103
8 may gradually increase, and the black display period of the liquid crystal panel 106 may be set longer. However, as the black display period becomes longer, light that irradiates the liquid crystal panel 106 and contributes to the original image display is obtained. The proportion decreases. Therefore, the discharge lamp 1
In the early stage of use, where the arc length of 00 is relatively short, an unnecessary black display period is set, the light use efficiency is reduced, and the brightness of the image projected on the screen is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and prevents color mixture without setting the black display period of the liquid crystal panel unnecessarily long even when the light emitting portion of the light source becomes large during use. It is another object of the present invention to provide a projection display device capable of displaying a bright, high-quality image.

[0015]

According to a first aspect of the present invention, there is provided a projection display apparatus comprising: a white light source; a light condensing means for condensing light emitted from the light source; and a light condensed by the light condensing means. Of which
Red, green, color selection means for selectively transmitting or reflecting light in the blue band in a predetermined order, and condensing the light transmitted or reflected by the color selection means, a spatial light modulation element described later Illuminating means for illuminating, a spatial light modulating element for modulating light incident from the illuminating means, and a projecting means for projecting the light modulated by the spatial light modulating element onto an external screen,
The incident light of the color selection means, or a part of the light transmitted or reflected by the color selection means is shielded, and light of a band of a color different from a color to be displayed on a screen is subjected to the spatial light modulation. Light shielding means for preventing light from entering the element.

According to a second aspect of the present invention, in the projection type display device according to the first aspect, the light shielding means comprises a member for blocking light, and has a predetermined size through which light passes. It has a light transmitting portion.

According to a third aspect of the present invention, there is provided the projection type display apparatus according to the second aspect, wherein the color selection means transmits or reflects the light according to the wavelength of the light.
The size of the light transmitting portion of the light shielding means changes.

According to a fourth aspect of the present invention, in the projection type display device according to the second aspect, light of a specific wavelength band is partially converted from light incident on the light transmitting portion of the light shielding means. It is characterized by comprising light removing means for removing.

According to a fifth aspect of the present invention, in the projection type display device according to the first aspect, the light shielding means is arranged on an emission side of the color selection means. Things.

According to a sixth aspect of the present invention, in the projection type display device according to the first aspect, the light shielding means is arranged so that an air distance from the color selecting means is 5 mm or less. It is characterized by the following.

According to a seventh aspect of the present invention, in the projection type display device according to the first aspect, the light source is an ultra-high pressure mercury lamp.

According to an eighth aspect of the present invention, in the projection type display device according to the first aspect, the condensing means is an ellipsoidal mirror.

According to a ninth aspect of the present invention, in the projection type display device according to the eighth aspect, the color selection means is arranged such that a light transmitting surface or a reflecting surface is in the vicinity of a long focal point of the elliptical mirror. Is characterized by being arranged in a.

According to a tenth aspect of the present invention, in the projection type display unit according to the first aspect, the color selecting means arranges fan-shaped red, green, and blue color filters in a disk shape. This is characterized in that light of each color band is sequentially transmitted by rotating the color wheel.

In a projection type display device according to an eleventh aspect of the present invention, in the projection type display device according to the tenth aspect, the light shielding means partially shields the incident light in the rotation direction of the color wheel. It is characterized in that light is not shielded in the radial direction of the color wheel.

In a projection type display apparatus according to a twelfth aspect of the present invention, in the projection type display apparatus according to the eleventh aspect, the light shielding means is a stop having an opening having a predetermined size through which incident light passes. The aperture width of the stop in the direction of rotation of the color foil is set to be equal to or smaller than the diameter of the converging spot formed on the color foil at the initial use of the light source, and is set in the radial direction of the color foil. The aperture width of the stop is set to be equal to or larger than the diameter of the focused spot.

According to a thirteenth aspect of the present invention, in the projection type display according to the first aspect, the light shielding means has a substantially circular cross section in a plane orthogonal to the optical axis. Things.

According to a fourteenth aspect of the present invention, in the projection type display device according to the thirteenth aspect, the light shielding means is substantially cylindrical.

According to a fifteenth aspect of the present invention, in the projection type display according to the thirteenth aspect, the light shielding means has a substantially conical shape.

[0030]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a projection type display device according to the present invention. (Embodiment 1) FIG. 1 is a diagram showing a configuration of a projection display apparatus according to Embodiment 1 of the present invention. In the figure, 10
Is a discharge lamp, 11 is an ellipsoidal mirror, 12 is a UV-IR cut filter, 13 is a light blocking aperture, 15 is a color foil, 1
6 is a rotation motor, 17 is a rotation control unit, 18 is a condenser lens, 19 is a field lens, 20 is a transmissive liquid crystal panel, 21 is a liquid crystal driving unit, and 22 is a projection lens.

The discharge lamp 10 is an ultra-high pressure mercury lamp. This type of lamp has a high luminance of a light emitting unit, can efficiently collect radiated light, has good color rendering properties, and is suitable for full-color display. The center of gravity of the light emitting portion 10a formed between the electrodes of the discharge lamp 10 is the first elliptical mirror.
It is arranged so as to approximately coincide with the focal point F1 (short focal point).

The ellipsoidal mirror 11 efficiently condenses the light emitted from the discharge lamp 10 and forms a converging spot 14 at the second focal point F2 (long focal point). The condensed spot 14 is a secondary light source equivalent to a real image of the light emitting unit 10a. The UV-IR cut filter 12 removes ultraviolet light and infrared light from the light emitted from the discharge lamp 10.

The light-blocking diaphragm 13 is a conical diaphragm arranged on the light exit side of the color wheel 15 and is formed by the elliptical mirror 11.
And shields part of the light transmitted through the color wheel 15. The material of the light-blocking diaphragm 13 is, for example, PPS.
By using a thermoplastic such as (polyphenylene sulfide, heat-resistant temperature of 260 ° C.), the light-blocking aperture 13 can be obtained at low cost by molding.

As shown in FIG. 2, for example, fan-shaped red, green, and blue color filters 15R,
5G and 15B are combined in a disk shape and fixed by a donut-shaped holder 15a, and are arranged so that the surface of the color wheel 15 overlaps the position of the second focal point F2 of the elliptical mirror 11. The color wheel 15 is provided with a rotation motor 16 such as a flat motor or a stepping motor.

The rotation control unit 17 receives video signals of each color of red, green, and blue, and according to a synchronization signal included in the video signals,
The rotation motor 16 is driven so that light having a band of each color passes through the color wheel 15 in synchronization with the display of each color of red, blue, and green on the liquid crystal panel 20. In addition, color foil 1
Position control is required to control the rotation of 5,
For example, the holder 15a of the color wheel 15 is black,
If a light reflection surface is provided on a part of the light reflection surface and the position is detected by a photo sensor or the like, the position can be detected.

The condenser lens 18 is a plano-convex lens of positive power, and efficiently condenses the light transmitted through the color wheel 15 onto the liquid crystal panel 20. The field lens 19 condenses the illumination light to the liquid crystal panel 20 by the condensing lens 18,
It is used for guiding to the projection lens 22.

The liquid crystal panel 20 is a ferroelectric liquid crystal panel including a liquid crystal layer and a bistable element for applying a voltage to the liquid crystal layer and switching between two ON / OFF states. In the liquid crystal panel 20, for example, by controlling the gradation expression by PWM (pulse width modulation), the ON time of the bistable element can be changed, and the orientation direction of the liquid crystal molecules can be changed. Further, the liquid crystal panel 20 is provided with a polarizing plate (not shown) on the incident side and the outgoing side, and the polarization axis is set according to the light distribution direction of the liquid crystal molecules. Since the response time of the bistable element is relatively short, it is suitable for performing color sequential display on the liquid crystal panel 20 as in the present invention.

The liquid crystal driver 21 controls the PW of the liquid crystal panel 20 according to the red, green, and blue video signals received from the external device.
M (pulse width modulation) control is performed. The projection lens 22 receives the transmitted light of the liquid crystal panel 20, magnifies the image on the liquid crystal panel 20, that is, an optical image, and enlarges the screen (not shown).
Enlarge and project upward.

The operation of the projection display device according to the first embodiment of the present invention will be described below. The light emitted from the discharge lamp 10 is collected by the ellipsoidal mirror 11 and
Incident on the color wheel 15
Is formed. Each of the color filters 15R, 15G, and 15B is focused on the condensed spot
, Light in the red, green, and blue bands sequentially passes through the color filters 15R, 15G, and 15B.

Then, for example, a period in which the liquid crystal panel 20 is controlled by the liquid crystal drive unit 21 based on a video signal for red display and a period in which the red filter 15R of the color wheel 15 passes through the condensing spot 14 are synchronized. Thus, the rotation control unit 17 controls the rotation of the color wheel 15. The rotation control unit 17 also controls the rotation of the color wheel 15 when receiving other green and blue video signals.

Thus, the color wheel 15 is rotated,
By switching the red, green, and blue monochrome gradation display in a time series in a short time and displaying on the liquid crystal panel 20, as a result, the image displayed on the screen is visually synthesized, and the observer can view the full color image. Recognize the image.

However, the color filters 15R, 15G,
For a certain period of time when the boundary of 15B passes through the condensed spot 14, the condensed spot 14 straddles two adjacent color filters in the color wheel 15, so that the liquid crystal panel 20 is driven to display black to prevent occurrence of color mixing. I do.

FIG. 3 is a diagram for supplementarily explaining the relationship between the color wheel 15 and the condensing spot 14 as viewed from the incident side of the color wheel 15, and the black display period of the liquid crystal panel 20 will be described with reference to FIG. . FIG. 3 shows an initial state of use of the discharge lamp 10.

When the color wheel 15 is rotating in the direction of the arrow in the figure, for example, the period during which the boundary 15RG between the red color filter and the green color filter passes through the condensing spot 14 is set to the black color of the liquid crystal panel 20. Display period. Similarly, with respect to the other boundaries 15GB and 15BR, a period during which the light passes through the converging spot 14 is defined as a black display period. Thus, during the black display period of the liquid crystal panel 20, the color wheel 1
5 is set three times per one rotation. During this black display period, the color wheel 1 is set at the beginning of use of the discharge lamp 10.
5 is set according to the size of the condensed spot 14 formed.

In a relatively early stage using the discharge lamp 10, the light condensed by the ellipsoidal mirror 11 reaches the color wheel 15, and the condensed spot 1 having the size shown in FIG.
4 is formed on the color wheel 15 surface. At this stage,
Since the period in which the condensed spot 14 extends over the adjacent two color filters is shorter than the black display period of the liquid crystal panel 20, a mixed color optical image is not formed on the liquid crystal panel 20.

On the other hand, as the discharge lamp 10 is used for a long time, the arc length increases, and as shown in FIG.
The diameter of the focused spot 14 increases in proportion to the arc length.
Accordingly, the period in which the condensed spot 14 straddles the adjacent two color filters is longer than the black display period of the liquid crystal panel 20, so that a mixed-color optical image is formed on the liquid crystal panel 20.

The above problem will be specifically described with reference to FIG. 3 and FIG.
, The liquid crystal panel 20 is driving for red display. And the boundary 15 of the color wheel 15
Immediately before the RG reaches the start point 31a of the black display period, that is, immediately before the liquid crystal panel 20 performs black display, since a part of the condensed spot 14 also exists in the green filter 15G area, Will display an image in which green is mixed with red.

Next, when the boundary 15RG reaches the end point 31b of the black display period 31, the liquid crystal panel 20 ends the black display, and immediately after that, starts driving for green display. However, at this time, since a part of the condensed spot 14 also exists in the red filter 15R region, an image in which green is mixed with red is displayed on the liquid crystal panel 20.

The boundaries 15 GB and 15 BR are focused light spots 1
Similarly, the liquid crystal panel 20 displays an image in which blue and green are mixed with each other and an image in which blue and red are mixed with colors that are different from the originally displayed colors when the light passes through No. 4.

For this reason, a longer black display period may be set in advance, assuming that the arc length of the light source becomes longer. However, when the black display period of the liquid crystal panel 20 becomes longer, the brightness of the displayed image becomes longer. Is undesirably reduced.

Therefore, in the present invention, in order to solve the above problem, the light is condensed by the ellipsoidal mirror 11 by the light-shielding aperture 13 and
A part of the light transmitted through the color wheel 15 is shielded to prevent the size of the condensed spot 14 from becoming larger than a desired size.

Hereinafter, referring to FIG. 5 and FIG.
The specific configuration and operation of the above will be described. FIG. 5 is a diagram for explaining the relationship between the color wheel 15, the condensing spot 14, and the light-blocking diaphragm 13 as viewed from the emission side of the color wheel 15, and shows an initial state of use of the discharge lamp 10.

In FIG. 5, it is necessary for the light-blocking aperture 13 to limit the size of the condensed spot 14 along the rotation direction of the color wheel 15. Accordingly, the opening width of the light-blocking aperture 13 in the rotation direction of the color wheel 15 is
0 is set to be approximately equal to the diameter of the converging spot 14 at the start of use. On the other hand, in the radial direction of the color wheel 15, it is not particularly necessary to limit the opening width of the light-blocking aperture 13, and it is sufficient to provide a sufficient opening width so as not to shield the condensing spot 14.

At a relatively early stage just after using the discharge lamp 10, the condensing spot 14 is small as shown in FIG. Never stop, light blocking aperture 1
3, the light use efficiency does not greatly decrease.

As shown in FIG. 6, when the size of the condensed spot 14 increases, immediately before and immediately after the black display period of the liquid crystal panel 20, light simultaneously enters the adjacent two color filters. The light-blocking aperture 13 blocks light contributing to the occurrence of color mixture, thereby preventing the occurrence of color mixture in an image. Moreover, by using the light-blocking aperture 13, the black display period of the liquid crystal panel 20 can be minimized, and a high-quality image can be obtained without deteriorating the brightness of the image.

The effect of the present invention can be obtained even if the opening width of the light-shielding stop 13 in the rotation direction of the color wheel 15 is set smaller than the diameter of the converging spot 14 when the discharge lamp 10 starts to be used. However, in this case, the light use efficiency is reduced according to the brightness distribution of the condensing spot 14.

Since the intensity of the transmitted light of the color wheel 15 is about ３ of the intensity of the incident light, the amount of light shielded by the light-shielding aperture 13 disposed on the emission side of the color wheel 15 is also small.
It is about 1/3 of the incident light. Thereby, heat generation of the light-blocking diaphragm 13 due to light is suppressed, and the reliability of the device is improved.

Further, since the light-blocking diaphragm 13 has a conical shape, the air resistance when the color wheel 15 rotates can be reduced, and the noise can be suppressed. The light-blocking diaphragm 13 is not limited to a conical one, and may be any shape as long as the surface perpendicular to the optical axis has a substantially circular cross section.

According to the projection display apparatus of the first embodiment of the present invention configured as described above, the black display period of the liquid crystal panel 20 can be set unnecessarily long by providing the light-blocking aperture 13. In addition, it is possible to prevent the occurrence of color mixture in an image, and to realize a projection display device capable of displaying a bright, high-quality image. Also, the light-blocking aperture 13
Is arranged on the exit side of the color wheel 15,
The temperature rise of the light-blocking diaphragm 13 can be suppressed, and the reliability of the device can be improved. Further, by making the shape of the light-blocking diaphragm 13 conical, it is possible to suppress noise when the color wheel 15 rotates.

(Embodiment 2)

FIG. 7 is a diagram showing a configuration example of a projection display apparatus according to Embodiment 2 of the present invention. In the figure, FIG.
The same reference numerals are the same or corresponding parts. FIG. 8 is a front view of the light-shielding stop shown in FIG. The second embodiment is different from the first embodiment in that the size of the opening of the light-blocking diaphragm 51 can be changed in synchronization with the display on the liquid crystal panel 20. Specifically, as shown in FIG.
It is composed of a main aperture 51a, a movable section 51b, and an aperture control motor 51c for driving the movable section 51b.

The opening shape of the main diaphragm 51a is the same as that shown in FIG. 5, and the opening width in the rotation direction of the color wheel 15 is different from the condensing spot 1 at the start of use of the discharge lamp 10.
4 is set to be approximately equal to the diameter. By driving the aperture control motor 51c, the movable part 51b moves from the position indicated by the solid line 51b 'to the position indicated by the wavy line 51b "or in the opposite direction to adjust the size of the opening of the light-shielding stop 51. Can be.

The drive of the aperture control motor 51c is performed by an aperture control unit 52 shown in FIG. Aperture control unit 52
Receives video signals of each color of red, blue and green from an external device,
The aperture control motor 51c is driven according to a synchronization signal included in the video signal, and control is performed so that the image display of the liquid crystal panel 20 and the opening and closing of the movable portion 51b of the light-shielding aperture 51 are synchronized.

For example, during the image display period when the liquid crystal panel 20 corresponds to red and blue, the movable part 51b of the light-shielding diaphragm 51 is moved to the position of the dashed line 51b 'by driving the control motor 51c. During the image display period in which 20 corresponds to green, the movable portion 51b is moved to the position of practice 51b ″. As a result, the amount of green light reaching the liquid crystal panel 20 decreases, and the white balance in white display changes. In this way, when light of a specific color passes through the light-blocking diaphragm 51, the white balance of the image can be arbitrarily adjusted by adjusting the size of the opening of the light-blocking diaphragm 51.

According to the projection type display apparatus of the second embodiment of the present invention configured as described above, the size of the aperture of the light-blocking diaphragm 51 can be adjusted in synchronization with the video signal. To prevent the display of mixed colors
It is possible to arbitrarily adjust the white balance of a display image, and to realize a projection display device capable of displaying a bright, high-quality image.

(Embodiment 3) FIG. 9 is a diagram showing a configuration example of a projection display apparatus according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG.
Reference numeral 61 denotes a color wheel unit. FIG. 10 is an exploded perspective view of the color wheel unit of FIG. The color wheel unit 61 includes a color wheel 71, a motor 7
3. Color wheel cases 74 and 75 are provided.

The color wheel 71 is formed by combining fan-shaped red, green, and blue color filters 71 R, 71 G, and 71 B in a disk shape and fixing them with a holder 72.
To rotate.

The motor 73 includes a rotating part 73a and a base plate 73.
The rotating portion 73a of the motor 73 is connected to the holder 72 of the color wheel 71, and the base plate 73b of the motor 73 is fixed to the color wheel case 74.

The color wheel case 74 includes an entrance window 77 having a sufficient size in an optical path covered with translucent glass, and a light-shielding stop 76. The color wheel case 75 has a sufficiently large exit window 78 in the optical path covered with the translucent glass.
It has. Further, instead of installing the UV-IR cut filter 12, at least one of the transparent glass provided in the entrance window 77 and the exit window 78 of the color foil cases 74 and 75 is used as a filter for removing ultraviolet rays and infrared rays. Is also good.

The light-shielding stop 76 has a stop opening protruding inside the color wheel case 74 so that the stop opening is disposed close to the color wheel 71. The protruding portion of the light-shielding stop 76 is formed in a columnar shape. The light-shielding stop 76 has an opening width in the rotation direction of the color wheel 15 that is smaller than the condensed spot 14 when the discharge lamp 10 is used.
Is set to be approximately equal to the diameter of The light-blocking aperture 76 may be separate from or integral with the color wheel case 74.

When the color wheel case 75 is fixed to the color wheel case 74, the color wheel 71 can be held in the closed space, and the safety when the color wheel 71 is damaged can be improved.

The light condensed by the ellipsoidal mirror 11 enters through the entrance window 77 of the color wheel case 74,
The light selectively transmitted through 1 exits from the exit window 78 of the color wheel case 75. The light-blocking aperture 76 has the same function as that of the first embodiment, partially blocks light incident on the color wheel cases 74 and 75, and prevents a mixed-color display of an image which becomes a problem after a long use of the discharge lamp 10. be able to.

Here, the color wheel 71, the motor 73,
When the color wheel cases 74 and 75 are fixed to each other, the air gap between the color wheel 71 and the light blocking aperture 76 is, for example, 2
mm. Thus, the color wheel 71
It is preferable that the air gap between the light shielding aperture 76 and
If it is set to be equal to or less than mm, a light shielding effect can be obtained efficiently.

As described above, even if the light-shielding stop 76 is arranged close to the color wheel 71, the projection of the light-shielding stop 76 is formed in a columnar shape.
The air resistance of the light-blocking aperture 76 during rotation is small, and noise can be reduced. Further, the projecting portion of the light-blocking diaphragm 76 may have a shape other than a columnar shape. For example, a similar effect can be obtained as long as the shape is such that the side surface of the projecting portion is inclined to have a conical shape and the air resistance is reduced. Can be.

According to the projection type display apparatus of the third embodiment of the present invention having the above-described configuration, the color wheel 7 is provided in the color wheel cases 74 and 75 provided with the light-blocking diaphragm 76.
By keeping the hermetically sealed 1, it is possible to prevent the color mixture display of the image by the liquid crystal panel 20 and to improve the safety performance. Furthermore, color wheel cases 74 and 75
The noise can be reduced by making the protruding portion of the light-blocking aperture 76 inside the shape having a relatively small air resistance. In addition, by setting the air gap between the color wheel 71 and the light-shielding diaphragm 76 within 5 mm, a light-shielding effect can be obtained efficiently.

(Embodiment 4) FIG. 11 is a diagram showing a configuration example of a projection display apparatus according to Embodiment 4 of the present invention.
In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and 81 denotes a light-shielding stop. FIG. 12 is a front view of the light-shielding stop shown in FIG. The light-blocking diaphragm 81 includes a main diaphragm 82 and an auxiliary diaphragm 83.

The opening width of the main stop 82 in the direction of rotation of the color wheel 15 is set to be substantially equal to the diameter of the condensed spot 14 at the start of use of the discharge lamp 10, as in FIG.

The auxiliary diaphragm 83 is formed by coating a multi-layer film 83b in a shaded area of the translucent glass 83a. The multilayer film 83b reflects only light of a specific wavelength with respect to incident light. The multilayer film 83b is vapor-deposited on the auxiliary diaphragm 83 so that the size of the non-deposition portion of the multilayer film 83b is smaller than the opening of the main diaphragm 82.

Thus, after the incident light of the light-shielding stop 83 passes through the opening of the main stop 82, the multilayer film 8 of the auxiliary stop 83
By 3b, light of a specific wavelength is partially reflected, and the amount of light passing through the specific wavelength is reduced. For example, if the multilayer film 83b reflects only the green band light, the incident light of the light blocking diaphragm 81 is reduced in the green band light and exits the light blocking diaphragm 81. Therefore, if the characteristics of the multilayer film 83b are set according to the spectrum of the light source, the white balance of the image displayed on the liquid crystal panel 20 can be set arbitrarily.

Further, instead of using the main stop 82 shown in FIG.
On the plane a, for example, silver, aluminum, or the like that efficiently reflects visible light may be deposited to form a deposited film having an operation equivalent to that of the main stop 82. In this case, the main stop vapor deposition film and the auxiliary stop multi-layer film 83b are formed by the transparent glass 8.
3a may be formed on the same plane, or may be formed on the front and back of the translucent glass 83a.

According to the projection type display device of the fourth embodiment of the present invention configured as described above, since the light shielding diaphragm 81 is provided with the multilayer film for reflecting light of a specific wavelength, the liquid crystal panel 20 It is possible to realize a projection-type display device that can display a bright and high-quality image while preventing color mixture display of images and arbitrarily adjusting the white balance of a display image.

The present invention is not limited to the embodiments described above, and various modifications and changes can be made without departing from the spirit of the present invention. For example, in the embodiment of the present invention,
Although an example in which an ultra-high pressure mercury lamp is used as the discharge lamp 10 has been described, a metal halide lamp, a xenon lamp, or the like may be used. In addition, a light source other than a discharge lamp such as a halogen lamp and an LED may be used.

Instead of the elliptical mirror 11, a configuration in which a parabolic mirror and a lens having a positive power are combined to collect the radiated light of the light source may be adopted. Further, the configuration may be such that the parallel light reflected by the parabolic mirror is used as it is as a condensing spot.

The arrangement of the light-blocking aperture 13 is not particularly limited.
The closer to the position where is formed, the more efficiently the color mixture display of the image can be prevented. Specifically, it is more preferable to dispose the light-blocking aperture 13 at a distance within 5 mm from the condensing spot 14 in the air.

It is preferable that the light-shielding diaphragm has a shape that reduces the air resistance when the color wheel 15 rotates, for example, a surface perpendicular to the optical axis has a substantially circular cross section. The light-blocking diaphragm may be arranged on either the incident side or the emission side of the color wheel 15, but it is more preferable to arrange the light-blocking diaphragm on the emission side because heat generation of the light-blocking diaphragm is suppressed.

The color wheel 15 may use a reflection type dichroic mirror instead of an absorption type filter, and select light in the red, green, and blue bands based on the reflected light.

The color wheel 15 is not limited to the one divided into three by red, blue and green filters, but may be divided into three or more. In addition, the shape of the color wheel 15 is not limited to a disk shape, and any shape can be used in which light of a specific wavelength band can be sequentially selected in time series with respect to incident light.
It can be used as a color selection means for implementing the present invention.

In the embodiment of the present invention, the example in which the ferroelectric liquid crystal panel 20 is used as the spatial light modulator is shown. However, any device having a response time capable of performing color sequential display can be used as the spatial light modulator. For example, a twisted nematic liquid crystal panel, a liquid crystal panel using light scattering, a DMD that forms an optical image corresponding to a video signal as a change in light diffraction, reflection, or the like may be used.

In the embodiment of the present invention, the condenser lens 18 is used as illumination means for illuminating the spatial light modulator, but two lens arrays or rod lenses may be used instead.

In the embodiment of the present invention, a projection type display device for performing front projection on a screen is described. However, a projection type display device for performing rear projection using a transmission type screen may be used. .

[0091]

As described above, according to the projection type display device of the first aspect of the present invention, the white light source, the light condensing means for condensing the light emitted from the light source, and the light condensing means. Of the emitted light, red, green, and color selection means for selectively transmitting or reflecting light in the blue band in a predetermined order, and condensing light transmitted or reflected by the color selection means, to be described later. Illuminating means for illuminating the spatial light modulation element to be illuminated, a spatial light modulation element for modulating light incident from the illuminating means, and projection means for projecting the light modulated by the spatial light modulation element onto an external screen, The incident light of the color selection means, or a part of the light transmitted or reflected by the color selection means is shielded, and light of a band of a color different from a color to be displayed on a screen is subjected to the spatial light modulation. Light shielding means for preventing light from entering the element Because it is formed, the black display period of the spatial light modulator to prevent color mixing without setting unnecessarily long, bright, can realize a projection type display device capable of high-quality image display.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a projection display device according to a first embodiment of the present invention.

FIG. 2 is a front view of the color wheel of FIG. 1;

FIG. 3 is a diagram illustrating a relationship between a color wheel and a converging spot as viewed from a light incident side in the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a relationship between a color wheel and a converging spot as viewed from a light incident side in the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a relationship between a color wheel, a light-converged spot, and a light-blocking aperture as viewed from a light emitting side in the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a relationship among a color wheel, a condensing spot, and a light-blocking aperture as viewed from a light emitting side according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a configuration example of a projection display device according to a second embodiment of the present invention.

FIG. 8 is a front view of the light-blocking stop shown in FIG. 7;

FIG. 9 is a diagram showing a configuration example of a projection display device according to a third embodiment of the present invention.

FIG. 10 is an exploded perspective view of the color wheel unit of FIG. 9;

FIG. 11 is a diagram showing a configuration example of a projection display according to a fourth embodiment of the present invention.

FIG. 12 is a front view of the light-shielding stop shown in FIG. 11;

FIG. 13 is a diagram showing a configuration example of a conventional projection display device.

FIG. 14 is a diagram illustrating a relationship between a color wheel and a converging spot in a conventional projection display device.

[Explanation of symbols]

 10, 100 Discharge lamp 10a, 100a Light emitting unit 11, 101 Ellipsoidal mirror 12, 102 UV-IR cut filter 13, 51, 76, 81 Light-blocking aperture 14, 108 Focusing spot 15, 71, 103 Color wheel 16, 73 Motor 17 Rotation control unit 18, 104 Condensing lens 19, 105 Field lens 20, 106 Liquid crystal panel 21 Liquid crystal driving unit 22, 107 Projection lens 52 Aperture control unit 74, 75 Color wheel case

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Sakaguchi 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) 2H088 EA13 HA12 HA14 HA23 HA24 HA28 MA06 2H091 FA01Z FA26X FA26Z FA34Z FA41Z LA15 LA17

Claims (15)

[Claims] 1. A white light source, a light condensing means for condensing light emitted from the light source, and a light in a red, green, and blue band selected from light condensed by the light condensing means in a predetermined order. A color selecting unit that transmits or reflects light, an illuminating unit that collects light transmitted or reflected by the color selecting unit, and illuminates a spatial light modulator, which will be described later, and modulates light incident from the illuminating unit. A light modulating element, a light projecting means for projecting light modulated by the spatial light modulating element onto an external screen, an incident light of the color selecting means, or a light transmitted or reflected by the color selecting means. And a light-shielding unit that shields a part of the light from the band and prevents light in a band of a color different from the color to be displayed on the screen from entering the spatial light modulation element. Type display device. 2. The projection type display device according to claim 1, wherein said light shielding means is made of a member for blocking light, and has a light transmitting portion of a predetermined size through which light passes. Display device. 3. The projection display device according to claim 2, wherein a size of a light transmitting portion of the light shielding unit changes according to a wavelength of light transmitted or reflected by the color selection unit. Projection display device. 4. The projection display device according to claim 2, further comprising a light removing unit that partially removes light of a specific wavelength band from light incident on the light transmitting part of the light shielding unit. Projection display device. 5. The projection display device according to claim 1, wherein the light shielding unit is arranged on an emission side of the color selection unit. 6. The projection display device according to claim 1, wherein the light-shielding unit has an air gap with the color selection unit of 5 mm.
A projection display device, which is arranged as follows. 7. The projection display according to claim 1, wherein the light source is an ultra-high pressure mercury lamp. 8. The projection type display device according to claim 1, wherein said condensing means is an ellipsoidal mirror. 9. The projection type display device according to claim 8, wherein said color selection means is arranged such that a light transmitting surface or a light reflecting surface is disposed near a long focal point of said elliptical mirror. Display device. 10. The projection display device according to claim 1, wherein the color selection means is a color wheel configured by arranging fan-shaped red, green, and blue color filters in a disk shape. A projection-type display device characterized in that light of each color band is sequentially transmitted by rotating. 11. The projection display device according to claim 10, wherein the light shielding unit partially shields the incident light in the rotation direction of the color wheel and does not shield the light in the radial direction of the color wheel. Projection type display device. 12. The projection display device according to claim 11, wherein the light blocking means is a stop having an opening of a predetermined size through which incident light passes, and the opening width of the stop in the rotation direction of the color wheel. Is set to be equal to or smaller than the diameter of the condensed spot formed on the color foil at the beginning of use of the light source, and the aperture width of the aperture in the radial direction of the color foil is set to the condensed spot. A projection type display device, wherein the projection type display device is set to be equal to or larger than the diameter of the projection display device. 13. The projection type display device according to claim 1, wherein said light shielding means has a substantially circular cross section on a surface orthogonal to an optical axis. 14. The projection display device according to claim 13, wherein said light shielding means is substantially cylindrical. 15. The projection display device according to claim 13, wherein said light shielding means has a substantially conical shape.