JP2003228129A - Optical engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical engine which can be decreased in parts and can be reduced in a manufacturing cost and size. <P>SOLUTION: The optical engine has projection illuminating means for converting the light of the three primary colors emitted from a light source to linearly polarized light and projecting this light, a video display element for modulating and reflecting the light projected by the projection illuminating means and projecting means for projecting the light reflected by the video display element, in which the optical engine is provided with two sheets of the video display elements. Accordingly, the number of components can be reduced as compared with the optical engine composed of three sheets of the video display elements (liquid crystal elements or DMDs) known from heretofore and the lowering of the manufacturing cost and downsizing of the optical engine are made possible. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical engine used for a projector or the like.

[0002]

2. Description of the Related Art Conventionally, in an optical engine used for a liquid crystal projector or the like, two types of systems, that is, a three-plate type and a single-plate type are known as a color moving image display system.

As shown in FIG. 4, a three-plate optical engine 200 converts light from a light source 201 such as an ultra-high pressure mercury lamp into a uniform light flux by an integrator 202, and then linearly polarizes it by a polarization conversion element 209. For example, a color separation filter 20 such as a dichroic mirror
The three primary colors are R (red), G (green), and B (blue). Then, the spatial intensity distribution is modulated by transmitting the light of each color through the transmissive image display element 204 (liquid crystal panel) provided exclusively for each of RGB, and then, for example,
Color image combining prism 205 such as dichroic prism
Combined with the screen through the projection lens 206
(Not shown) is projected. Note that reference numeral 2
Reference numeral 07 denotes a field lens that superimposes and collects illumination light on the image display element 204, and reference numeral 208 denotes a mirror that reflects light.

As shown in FIG. 5A, a single plate type optical engine 300 has three color filters of RGB.
A liquid crystal panel with a color filter 301 (FIG. 5) which is provided with a plurality of color display pixels, each of which is a set of three RGB pixels, is arranged on the corresponding liquid crystal pixel.
(See (B)), and the light modulated by the color display pixels is projected on the screen via the projection lens 206.

[0005]

However, in the above-described three-plate type, since three image display elements 204 are required, the manufacturing cost of the optical engine 200 becomes relatively high, and the optical engine 200 becomes large in size. There was a problem. In addition, there is a problem in that when the light is combined by the color image combining prism 205, adjustment work for matching the angle of view of the three image display elements 204 must be performed.

Further, in the above-mentioned single plate type, since one color display pixel is formed by three pixels of RGB, there is a problem that a liquid crystal panel having three times higher definition than that of the three plate type is required. . There is also a problem that light is absorbed when it passes through the color filter, resulting in low light utilization efficiency.

In view of the above problems, the object of the present invention is to
An object of the present invention is to provide an optical engine which can reduce the size and cost of parts and manufacturing.

[0008]

In order to solve the above-mentioned problems, an optical engine (10, 70) according to claim 1 converts light of three primary colors emitted from a light source (20) into linearly polarized light and projects it. Projection illumination means (30, red / blue light projection illumination means 80, green light projection illumination means 90), an image display element (42) for modulating and reflecting the light projected by the projection illumination means, and An optical engine comprising a projection means (projection lens 50) for projecting light reflected by an image display element, characterized in that it comprises two image display elements.

According to the first aspect of the invention, the optical engine is composed of two image display elements. Therefore, for example, the number of components can be reduced, and the manufacturing cost of the optical engine can be suppressed, as compared with the conventionally known optical engine composed of three image display elements (liquid crystal element or DMD). The optical engine can be downsized.

The optical engine according to claim 2 is the optical engine according to claim 1.
The optical engine according to claim 1, wherein one of the two image display elements (the image display element for green light 42).
b, 101) is dedicated to green light.

According to the second aspect of the present invention, the same effect as that of the first aspect can be obtained, and one of the two image display elements is dedicated to green light. Therefore, for example, when an LED is used as a light source, if the light source size is the same, the relative luminous intensity of green light required for white display is smaller than that of blue light.
If one of the image display elements is dedicated to green light and the green light is constantly lit, the green light emission time can be made longer than the blue light emission time, resulting in a more natural state. It is possible to obtain white light close to.

The optical engine according to claim 3 is the optical engine according to claim 1.
Or the optical engine according to 2, wherein one of the two image display elements (red / blue light image display element 42a) is alternately used for red light and blue light by time division. It is characterized by being used.

According to the third aspect of the present invention, the same effect as that of the first or second aspect can be obtained, and if, for example, an image display element capable of high-speed switching is used, the image sensed by the viewer is displayed. Flicker can be suppressed.

The optical engine according to claim 4 is the optical engine according to claim 1.
The optical engine according to any one of items 1 to 3, wherein the image display element is a liquid crystal element.

According to the invention of claim 4, claim 1
In addition to obtaining the same effect as any one of 3), since the liquid crystal element is used as the image display element, the manufacturing cost of the optical engine can be suppressed and the power consumption of the optical engine can be suppressed.

The optical engine according to claim 5 is the optical engine according to claim 4.
The optical engine as described above, wherein the liquid crystal element is an LCO.
It is characterized by being S (Liquid Crystal on Silicon).

According to the invention of claim 5, the same effect as that of claim 4 can be obtained, and at the same time, the LC as an image display device can be obtained.
Since the OS element is used, high-speed switching of the image display element is possible, and flicker of the projected image can be suppressed.

The optical engine according to claim 6 is the optical engine according to claim 1.
The optical engine according to any one of claims 1 to 5, wherein the light source is a light emitting diode (LED 21, 22, 23).
Is characterized in that.

According to the invention of claim 6,
In addition to obtaining the same effect as in item 5, since light emitting diodes of three primary colors are used as a light source, a large number of various color separation filters and relay lenses are provided like a conventional optical engine using a super high pressure mercury lamp as a light source. There is no need, and the component structure of the optical engine can be simplified.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. [First Embodiment] As shown in FIG. 1, an optical engine 10 according to the first embodiment includes a light source 20, projection illumination means 30, image display means 40, projection lens 50 (projection means), and synchronization. It is roughly configured by a circuit (not shown) and the like.
The reference numeral 60 indicates the light from the light source 20 to the image display element 42.
Is an optical system for converting into a pseudo-parallel light flux.

The light source 20 includes R (red), G (green), and B.
A light emitting diode 21 that emits light beams of three primary colors of (blue),
22 and 23 (hereinafter, referred to as "LEDs 21 to 23"). Each of the LEDs 21 to 23 is connected to a synchronization circuit (not shown), and emits R, G, and B according to a synchronization signal supplied from the synchronization circuit.

The projection illumination means 30 is provided to convert the light of the three primary colors emitted from the LEDs 21 to 23 into linearly polarized light and illuminate the image display means 40.
1a to 31c, color combining prism 32, integrator 3
3 and so on. The polarization conversion elements 31a to 31c are well-known elements that convert incident light into linearly polarized light in a predetermined direction, and the three polarization conversion elements 31a to 31c for red light, green light, and blue light are each LED 21. 23 to 23 and the color synthesizing prism 32. The polarization conversion element 31a for red light and the polarization conversion element 31c for blue light are LEDs.
The polarization conversion element 31b for green light converts the red light and the blue light emitted from the light sources 21 and 23 into S-polarized light.
It is set so as to convert the green light emitted from the device into P-polarized light.

The color combining prism 32 is a polarization conversion element 31.
It is provided to combine the linearly polarized lights of the three primary colors that have passed through a to 31c and guide them to the integrator 33. The linearly polarized light that has passed through the color combining prism 32 is converted into a uniform illumination light flux by the integrator 33, and the image display means It is emitted toward 40.

The image display means 40 is provided for giving image information to the light from the projection illumination means 30 and emitting it to the projection lens 50, and comprises a polarization beam splitter 41, an image display element 42 and the like. The polarization beam splitter 41 has an S-polarized reflection surface 41a that reflects S-polarized light and transmits P-polarized light,
It is a well-known optical component that splits incident light into S-polarized light and P-polarized light.

The image display element 42 spatially modulates the incident light in accordance with the image signal, converts the incident light into a polarization plane component orthogonal to the polarization plane of the incident light, and reflects the polarization plane component. In the present embodiment, LCOS capable of high-speed switching
(Liquid Crystal On Silicon) element is used. As the image display elements 42, there are red / blue light image display elements 42a used for red light and blue light, and green light image display elements 42b used for green light. The display element 42a has an optical axis L of the incident light from the projection illumination means 30 to the polarization beam splitter 41.
Is arranged vertically to the green light image display element 42b.
Are arranged perpendicular to an optical axis L ′ that is orthogonal to the optical axis L of the incident light.

Further, as will be described later in detail, these red
A synchronizing circuit is connected to the image display element for blue light 42a and the image display element for green light 42b, and the R, G, and B image signals are red / red according to the synchronizing signal from the synchronizing circuit.
It is supplied to the image display element 42a for blue light and the image display element 42b for green light. The red / blue light image display element 42a and the green light image display element 42b spatially modulate the incident light and convert the incident light into a polarization plane component orthogonal to the polarization plane of the incident light to be reflected. There is. The projection lens 50 is provided for enlarging and projecting the light emitted from the image display means 40 onto a screen (not shown).

The synchronizing circuit is provided to drive and control the LEDs 21 to 23 and the image display element 42 (red / blue light image display element 42a and green light image display element 42b) in synchronization with each other. Specifically, the synchronization circuit
The R, G, and B lights are displayed at a predetermined timing on the image display element 42.
The drive of each of the LEDs 21 to 23 is controlled so that the light is emitted to. In addition, the synchronization circuit controls the video signals of R, G, and B to be supplied to the video display element 42 in synchronization with the drive control of the LEDs 21 to 23, and modulates the lights of R, G, and B. The drive of the image display element 42 is controlled so as to do so.

Next, how the light travels in the optical engine 10 will be described. The light of the three primary colors emitted from the LEDs 21 to 23 respectively corresponds to the polarization conversion elements 31a to 31c.
Incident on the polarization conversion element 31 for red light and blue light.
The light is converted into S-polarized light by a and 31c, and the green light is converted into P-polarized light by the polarization conversion element 31b.

The linearly polarized light of these three primary colors passes through the color combining prism 32 and enters the integrator 33, is converted into a uniform light beam by the integrator 33, passes through the field lens system 60, and enters the polarization beam splitter 41. To do. Of the linearly polarized light of the three primary colors incident on the polarization beam splitter 41, the red light and blue light converted into P-polarized light are transmitted through the S-polarized reflection surface 41a and are
The light is vertically incident on the blue light image display element 42a. here,
As described above, the synchronizing circuit supplies the video signals of R, G, and B to the video display element 42 in synchronization with the driving of the LEDs 21 to 23, so that the red light and the blue light are the video display elements for red / blue light. The signal 42a is modulated based on the R and B video signals, converted into S-polarized light, reflected and returned. Then, the red light and the blue light that have returned to the polarization beam splitter 41 again are reflected in the direction of the projection lens 50 of the optical axis L ′ orthogonal to the optical axis L on the S-polarized reflection surface 41a, and enter the projection lens 50.

The green light converted into S-polarized light is reflected on the S-polarized reflection surface 41a in the direction opposite to the projection lens 50 of the optical axis L'which is orthogonal to the optical axis L, and the green light image display element 42b. Vertically incident on. Then, the green light is modulated by the green light image display element 42b based on the G image signal, converted into P polarized light, reflected and returned. Then, the green light returning to the polarization beam splitter 41 again passes through the S-polarized reflection surface 41 a and enters the projection lens 50. In this way, the light given the video information
The image is enlarged and projected on the screen via the projection lens 50.

Next, drive control of the LEDs 21 to 23 and the image display element 42 by the synchronous circuit will be described. Figure 2
, The n-th video (n-th Scene
e), (n + 1) th video ((n + 1) th Sce
ne), (n + 2) th video ((n + 2) th Sc
When the images are sequentially projected on the screen in the order of "ene) ...", the synchronizing circuit controls the driving of the LEDs 21 to 23 so that the green light is constantly turned on, and the red light is emitted at a time interval of, for example, 10 ms. Light and blue light are turned on alternately.

Further, the synchronizing circuit synchronizes with the drive control of the LEDs 21 to 23, and R, G, B to the image display element 42 (the image display element 42a for red / blue light and the image display element 42b for green light). Each video signal is supplied.

Specifically, the synchronizing circuit supplies the n-th video signal for green to the video display element 42b for green light, and then supplies the n-th video signal for red and blue for 10 ms in this order. The image is supplied to the red / blue light image display element 42a at intervals. Next, in the same way as the nth video, (n + 1)
With respect to the th video, the (n + 1) th video signal for green is supplied to the video display element for green light 42b,
The (n + 1) th red and blue video signals are supplied in this order to the red / blue light video display element 42a at 10 ms intervals. In this way, the synchronization circuit supplies a predetermined video signal to the video display element 42 corresponding to the light being lit, and causes the video display element 42 to sequentially perform the light modulation processing.

The repetition frequency of the light modulation process by the red / blue light image display element 42a is 50 to 60H.
It is preferable that the duty ratio is about 50% at z, more preferably 60 Hz or more.

The LEDs 21 through the synchronous circuit as described above
By controlling the driving of the LED 23 and the image display element 42, the LED 2
The lights emitted by the projectors 1 to 23 are sequentially modulated by the image display element 42, and a full-color image in which R, G, and B lights are mixed is projected on the screen through the projection lens 50. Become.

As described above, according to the optical engine 10 shown in the first embodiment, as the image display element 42,
Two liquid crystal elements, a red / blue light image display element 42a and a green light image display element 42b, are used. So, for example,
Three conventionally known image display elements (liquid crystal elements)
The number of components can be reduced, the manufacturing cost of the optical engine 10 can be suppressed, and the optical engine 10 can be downsized as compared with the optical engine configured by.

Further, two LCs are used as the image display element 42.
Since the OS element is used, the color image combining unit can be configured with one polarization beam splitter 41 without using an expensive color image combining prism such as a dichroic prism. Therefore, the manufacturing cost of the optical engine 10 can be suppressed, and the labor required for the adjustment work for matching the angle of view can be reduced to half by using the color image combining prism. The dichroic color synthesizing element 32 used in the light source 20 may be a combination of filters or a prism, but since the image synthesizing function is not necessary, there is no problem with low shape accuracy, and compared with the color image synthesizing prism 205 of the conventional example. It is quite cheap. In addition, LCOS used as a video display element is DMD (Digita
Since it is cheaper than a micromirror device), the manufacturing cost of the optical engine shown in the present embodiment can be compared with, for example, a conventionally known single-plate optical engine using DMD. Can be suppressed.

In general, in the LEDs 21 to 23, the luminous intensity of green light is larger than the luminous intensity of blue light by a difference in luminous efficiency, but in order to obtain a natural white, the luminous intensity of green light is further increased. There is a need. In the optical engine 10 shown in the first embodiment, one of the two image display elements 42 is dedicated to green light, and the green light is constantly turned on,
The emission time of green light is set longer than that of blue light. Therefore, it is possible to obtain white light that is closer to the natural state as compared with the case of blinking green light in a predetermined cycle.

Further, since the light modulation processing is performed using the reflection type liquid crystal display element as the image display element 42, for example, as compared with the case of using the transmission type liquid crystal display element which transmits and modulates the light, The loss of light at the time of modulating light can be suppressed by the large aperture ratio of the pixel. Therefore, the projected image can be made brighter and the image quality can be improved.

Since the image display element 42 uses LCOS capable of high-speed switching to modulate light,
The flicker of the projected image can be suppressed. In particular,
When the repetition frequency of the light modulation processing by the red / blue light image display element 42a is set to 50 to 60 Hz, the flicker of the image felt by the viewer can be further suppressed, and when it is set to 60 Hz or more. In addition, the viewer can see the image with almost no flicker of the image.

The LED 2 used as the light source 20
Due to their characteristics, 1 to 23 are light emitting elements that emit a monochromatic light beam having a relatively narrow band width centered on the peak wavelength, and have high responsiveness when turned on and off. So, for example,
Unlike the conventional optical engine 200 using the ultra-high pressure mercury lamp, it is not necessary to provide various dichroic filters and color wheels, and the manufacturing cost of the optical engine 10 can be suppressed. Further, unlike the bubble lamp such as the ultra-high pressure mercury lamp, the LEDs 21 to 23 do not emit ultraviolet rays or strong infrared rays, so that a cutoff filter for ultraviolet rays or infrared rays is not necessary, and the configuration of the optical engine 10 can be simplified. it can.

The present invention is not limited to the above-mentioned embodiment, but the specific shape and structure can be changed as appropriate. For example, as the image display element 42, an LCO
Although S is used, the present invention is not limited to this, and for example, a DMD (Digital Micromirror Decoder) capable of high-speed switching is used.
vice) or other types of reflective image display elements may be used, or other image display elements such as transmissive liquid crystal display elements may be used.

[Second Embodiment] Next, the second embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. The optical engine 70 of the second embodiment is different from the optical engine 10 of the first embodiment in that the projection illumination means 80 for red / blue light and the projection illumination means 90 for green light are separated. In addition, a transmissive liquid crystal display element is used as the green light image display element 101. In addition, about the structure similar to the optical engine 10 of 1st Embodiment, the same code | symbol is attached | subjected in FIG. 3, and the detailed description is abbreviate | omitted. The drive control of the LEDs 21 to 23 and the image display elements (red / blue light image display element 42a, green light image display element 101) by the synchronization circuit is the same as that in the first embodiment.

The projection / illumination means 80 for red / blue light includes a color combining prism 81, an integrator 82, and a polarization conversion element 8.
3 and the like, and one polarization conversion element 83 is installed by installing the polarization conversion element 83 behind the integrator 82.
Is shared by red light and blue light.

The red light and the blue light emitted from the LEDs 21 and 23 pass through the color synthesizing prism 81, enter the integrator 82, are converted into a uniform light flux by the integrator 82, and are then S-polarized by the polarization conversion element 83. Is converted into the image and emitted to the image display means 100. The way in which the red light and the blue light travel in the image display means 100 is the same as in the first embodiment.

The projection illumination means 90 for green light is provided with a polarization conversion element 91, an integrator 92, etc.
The green light emitted from 22 is converted into S-polarized light by the polarization conversion element 91, converted into a uniform light flux by the integrator 92, and incident on the image display means 100.
As described above, the transmissive liquid crystal display element is used as the green light image display element 101 of the image display means 100.
When passing through the green light image display element 101, the green light is modulated based on the green image signal and is converted into P-polarized light.

Then, the green light passes through the S-polarized reflection surface 41a and enters the projection lens 50. Then, the light to which the image information for each color is given is enlarged and projected on the screen through the projection lens 50. Here, as in the first embodiment, since the green light is constantly turned on, for example,
Even if a transmissive liquid crystal display element having a slower response speed than that of a reflective image display element such as LCOS is used as an image display element for green light, no problem occurs in the image.

As described above, according to the optical engine 70 shown in the second embodiment, the single polarization conversion element 83 is shared by the red light and the blue light. In comparison with the one using the three polarization conversion elements 31 like the optical engine 10 shown in the embodiment,
The manufacturing cost of the optical engine 70 can be suppressed, and the optical engine 70 can be downsized.

[0049]

According to the first aspect of the invention, the image display means is composed of two image display elements. Therefore, for example, the number of components can be reduced, and the manufacturing cost of the optical engine can be suppressed, as compared with the conventionally known optical engine composed of three image display elements (liquid crystal element or DMD). The optical engine can be downsized.

According to the second aspect of the invention, the same effect as that of the first aspect can be obtained, and one of the two image display elements is dedicated to green light. Therefore, for example, when an LED is used as a light source, the luminous intensity of green light needs to be higher than that of blue light. If the green light is exclusively used and the green light is always turned on, the light emission time of the green light can be made longer than that of the blue light, and white light close to a natural state can be obtained.

According to the third aspect of the present invention, the same effect as that of the first or second aspect can be obtained, and if, for example, an image display element capable of high-speed switching is used, the image sensed by the viewer is displayed. Flicker can be suppressed.

According to the invention described in claim 4,
In addition to obtaining the same effect as any one of 3 above, since the liquid crystal element is used as the image display element, the manufacturing cost of the optical engine can be suppressed and the power consumption of the optical engine can be suppressed.

According to the invention of claim 5, the same effect as that of claim 4 can be obtained, and at the same time, the LC as an image display element can be obtained.
Since the OS element is used, the image display element becomes brighter and high-speed switching of the image display element is possible, and the flicker of the projected image can be suppressed.

According to the invention described in claim 6,
In addition to the effect similar to that of 5, the light source uses a light emitting diode which has high responsiveness when turned on and off. Therefore, for example, various dichroic filters and color wheels such as a conventional optical engine using an ultra-high pressure mercury lamp as a light source. Therefore, the manufacturing cost of the optical engine can be suppressed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an optical engine according to a first embodiment.

FIG. 2 is a diagram for explaining an example of synchronous drive control of an optical engine by a synchronous circuit.

FIG. 3 is a schematic configuration diagram showing an optical engine according to a second embodiment.

FIG. 4 is a schematic configuration diagram showing a conventional three-plate optical engine.

FIG. 5 is a schematic configuration diagram (A) and (B) showing a conventional single-plate optical engine.

[Explanation of symbols]

10 Optical engine 20 light sources 21-23 Light emitting diode (LED) 30 Projection illumination means 40 video display means 42 Image display device 42a Image display device for red / blue light 42b Image display device for green light 70 Optical engine 80 Red / blue light projection illumination means 90 Projection illumination means for green light 100 video display means 101 Image display device for green light

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 21/14 G03B 21/14 A H04N 9/31 H04N 9/31 C F term (reference) 2H052 BA01 BA02 BA06 BA09 BA14 2H088 EA14 HA13 HA20 HA24 HA28 MA20 2H091 FA10Z FA14Z FA26X FA26Z FA42Z FA45Z LA12 LA16 5C060 GB02 HA18 HC01 HC14 HC19 HC22 JB06

Claims (6)

[Claims] 1. A projection illumination means for converting light of three primary colors emitted from a light source into linearly polarized light and projecting the light, an image display element for modulating and reflecting the light projected by the projection illumination means, and the image display element. An optical engine comprising: a projection unit configured to project light reflected by the image display element; and two image display elements. 2. The optical engine according to claim 1, wherein one of the two image display elements is dedicated to green light. 3. The optical engine according to claim 1, wherein one of the two image display elements has one image display element,
An optical engine which is alternately used for red light and blue light by time division. 4. The optical engine according to claim 1, wherein the image display element is a liquid crystal element. 5. The optical engine according to claim 4, wherein the liquid crystal element is an LCOS (Liquid Crystal on Silico).
Optical engine characterized by being n). 6. The optical engine according to claim 1, wherein the light source is a light emitting diode.