CN1352404A - Dual-lens projection display device - Google Patents

Abstract

A double-lens projection display device is prepared as separating white light out of the first and second color lights to be sent to the first light polarization selector and the third color light to be sent to a reflector by a spectroscope, changing polarity of the first color light by the first light polarization selector, projecting the first and second color lights to two light valves for modulation by the first polarized light splitting prism, sending it to the second light polarization selector again to change polarity of the first color light and projecting it out by the first lens. The third color light is reflected by the reflector, projected to another light valve through a second polarized light splitting prism for modulation, and emitted by a second lens, so as to be overlapped with the first and second color lights sent by the first lens.

Description

Dual-lens projection display device

The invention relates to a projection display device, in particular to a dual-lens projection display device.

Common reflective liquid crystal light valve projection display devices include single-lens and three-lens types. The single-lens type has the characteristics of light, thin, small, and easy to carry, but it is difficult to design a large projection in a short distance due to the back focus The area of the lens, and the quality and precision of the used lens and beam splitter and other related components must be very high, resulting in an increase in cost. For example, in the past single-lens projection display devices, due to the use of a light-combining prism made of four right-angle prisms, it has the following disadvantages:

1. It is difficult to manufacture light-combining prisms. The reason is that the precision requirements of the four right-angle prisms must be very high during manufacture, otherwise the magnification of the light-combining prisms used to synthesize three-color light (such as red, blue, and green light) will be lower. Different, resulting in pixels can not overlap.

2. Since there is a glue line between the four right-angle prisms, the current pixel size must be below 5 micron (1 micron is 10-6 meters) to avoid stripes on the projected screen. When the resolution of the liquid crystal light valve increases , the existence of the glue line between the four right-angle prisms will have a negative impact on the imaging quality.

3. Since the light-combining prism cannot provide complete reflection or penetration of various colors of light, it will cause the problem of cross talk of red, blue, and green lights. For example, the colored lights sent by any red, blue, and green liquid crystal light valves When passing through the light-combining prism, it will irradiate on the other two liquid crystal light valves due to partial reflection or penetration of the light-combining prism, resulting in color impurity.

4. The back focus is too long. This is because the lens and the liquid crystal light valve are separated by a light-combining prism, causing the distance of the back focus to become longer.

There is also a single-lens type projection display device that does not use the above-mentioned light-combining prism, such as the single-lens type projection display device 1 shown in Figure 1, the single-lens type projection display device 1 includes a first light polarization selector 111, a The second light polarization selector 112, a polarized beam splitting prism 12, a two-color light separating prism 13, a first and a third light valve 141-143, a polarizing plate 15, a lens 16, etc., can make a white light 10 Separate the first, second, and third color lights 101, 102, and 103 (such as red, blue, and green) that can be synthesized into the white light, so that the first, third color lights 101-103 are respectively subjected to the first and third color lights that are set correspondingly. - Modulation of the third light valve 141-143.

The first and second light polarization selectors 111, 112 can adopt the ColorSelect Filters product manufactured by ColorLink Company, which is used to convert the polarity of the polarized predetermined color light (such as green light), for example, the original S(P ) polarized green light into P(S) polarized green light, and the first and second light polarization selectors 111 and 112 in the design of FIG. 1 are used for polarity conversion for the third color light 103 .

The polarized light splitting prism 12 can vertically reflect the S-polarized colored light and directly transmit the P-polarized colored light.

The two-color light separation prism 13 is used to separate predetermined two kinds of color light. In the design of FIG. And the second color light 102 is vertically reflected to achieve the effect of separating two different color lights.

The above-mentioned first-third color lights 101-103 are respectively projected on these first-third light valves 141-143, and when these first-third light valves 141-143 are biased and turned on, they can be modulated And change the polarity of its polarization to reflect and send the colored light of different polarities in the opposite direction. The following descriptions are all described under the condition that the first-third light valves 141-143 are turned on.

The polarizing plate 15 is used to purify the passing colored lights with predetermined polarities, and the design in FIG. 1 is used to purify the passing colored lights with P polarization.

Therefore, when a polarized (for example, S-polarized) white light 10 is projected through the first light polarization selector 111, the first and second color lights 101, 102 maintain the original S polarization, while the third color light 103 is converted to P polarization. Then when each color light is sent to the polarized light splitting prism 12, the first and second colored light 101, 102 (such as red and blue light) of S polarization are vertically reflected and sent to the two-color light by the polarized light splitting prism 12 A split prism 13 (Dichroic splitter prism), and make the P-polarized third color light 103 (such as green light) directly pass through the polarized light splitter prism 12.

When the S-polarized first and second color lights 101 and 102 reach the two-color light separation prism 13, the first color light 101 directly passes through the two-color light separation prism 13 and is projected on the first light valve 141, and is received by the first light valve 141. The light valve 141 modulates to change the polarity, and then reflects and sends out the P-polarized first color light 101 in the opposite direction, and then successively passes through the two-color light separation prism 13 and the polarized light separation prism 12, and continues to pass through the second light polarization selector 112 and the second light polarization selector 112. The polarizer 15 is used to obtain more purified P-polarized first color light 101 by passing through the polarizer 15 .

When the S-polarized second color light 102 reaches the two-color light separation prism 13, it is vertically reflected and projected on the second light valve 142, and after being modulated by the second light valve 142, the P-polarized second color light in the opposite direction is reflected 102, then vertically reflected by the two-color light splitting prism 13 and passing through the polarized light splitting prism 12, and then passing through the aforementioned second light polarization selector 112 and polarizer 15 successively to obtain more purified P-polarized second color light 102.

The third color light 103 that is transformed into P polarization by the first light polarization selector 111 and directly passes through the polarized light splitting prism 12 is projected on the third light valve 143, and is reflected and sent out in the opposite direction after being modulated by the third light valve 143. The S-polarized third color light 103 is then vertically reflected by the polarizing light splitter prism 12, and then successively passes through the aforementioned second light polarization selector 112 and polarizing plate 15, and the second light polarization selector 112 converts it into P Polarization, and then by passing through the polarizer 15 to obtain more purified P-polarized third color light 103 .

The first, second, and third color lights 101, 102, and 103 of the above-mentioned P polarization are sent out from the polarizer 15, and then pass through a lens 16 for projecting each color light to synthesize an image, so that each color light can be projected through the lens 16 Composite images on the preset projection screen.

The light combining prism composed of four prisms is not used in the components of the single-lens projection display device 1 in the past, but the first and second color lights 101, 102 can be combined by a polarized beam splitting prism 12 and a The separated two-color light separation prism 13 is matched with two first and second light polarization selectors 111 and 112 that can change the polarity of the predetermined color light (third color light 103 ), so as to separate the white light into the three color light through each After the light valve is modulated, the effect of combining light can be obtained, but it also has a too long back focus in design. In addition, the used two-color light separation prism 13 has a different effect on the spectrum of the first color light 101 (red light). Shift (shift) phenomenon, thereby affects its imaging quality, and the tertiary color light that is converted into P polarized when passing polarizing beam splitting prism 12, as known in the prior art, owing to the limitation of the manufacturing technology of polarizing beam splitting prism 12, The polarized beam splitting prism 12 may not have high penetration efficiency, and a considerable amount of P-polarized third color light will be reflected into the first light valve 141 and the second light valve 142 , which reduces the image contrast.

In addition, regarding the design of the three-lens projection display device, although the volume is large, the back focus is short, and it is easier to design a projection lens that can project a larger area within a shorter distance. However, the three lenses used Compared with the alignment of three liquid crystal light valves, it is more difficult to configure the offset. At least two sets of light valves and lenses need to be adjusted for alignment. Of course, there are also designs that require alignment adjustments for three light valves and three lenses. , so that the images of the three lenses are overlapped and projected at the same position.

The aforementioned common single-lens projection display device either has the disadvantage of using a light-combining prism composed of four prisms, or has the disadvantage of shifting the frequency spectrum of the predetermined color light due to the use of a two-color light separation prism. However, the design of the three-lens projection display device has relatively difficult offset configurations in the alignment of the three lenses with respect to the three liquid crystal light valves.

The object of the present invention is to provide a dual-lens type projection display device, which only needs to adjust the alignment of a single light valve and a single lens, and avoids the use of a light-combining prism and a two-color light-separating prism composed of four prisms. The manufacturing difficulty is reduced and the shift of the frequency spectrum of the predetermined color light is avoided.

In the dual-lens projection display device of the present invention, a spectroscopic mirror is used to separate the predetermined polarized white light into a first and second color light that travels in a predetermined direction and then arrives at a first light polarization selector, and then goes to a first light polarization selector. The third color light that travels in a different direction and arrives at a reflecting mirror, after changing the polarity of the first color light by the first light polarization selector, continues to pass through a first polarizing light splitting prism to separate the first and second color light respectively. The two-color light is projected to a first and second light valve for modulation, and then sent to a second light polarization selector, and the polarity of the first color light is changed again, and then sent to a first lens to be projected. The third color light is reflected by the reflector and passes through a second polarized light splitting prism, and is projected to a third light valve for modulation, and then sent to a second lens to project, which is the same as the first lens projected by the aforementioned first lens. , The second color light is superimposed to synthesize the image.

The dual-lens projection display device of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments, in the figures:

FIG. 1 is a schematic top view of an existing single-lens projection display device;

FIG. 2 is a schematic perspective view of a dual-lens projection display device according to an embodiment of the present invention;

Fig. 3 is a schematic side view of the first and second color light transmission process in the embodiment of the present invention;

Fig. 4 is a schematic side view of the third color light transmission process in the embodiment of the present invention.

As shown in Figure 2, it is a dual-lens type projection display device according to an embodiment of the present invention. The dual-lens type projection display device 2 includes a beam splitter 21, a first light polarization selector 221, a second light polarization selector 222, a The first polarizing beam splitting prism 231, a second polarizing beam splitting prism 232, a first-third light valve 241-243, a reflection mirror 25, and a first lens 26 and a second lens that are arranged parallel to the same plane 27, etc., and a white light 3 can be separated into the first, second, and third color lights 31, 32, and 33 (such as red, blue, and green) that can be synthesized into the white light, so that the first-third color light 31 -33 are respectively modulated by the corresponding first-third light valves 241-243. The case where the first-third light valves 241-243 are in the conduction state will be described below.

The beam splitter 21 is used to vertically reflect the first and second color light 31 , 32 (such as red and blue light), and directly pass the third color light 33 (such as green light).

The first and second light polarization selectors 221, 222 can use the ColorSelect Filters product manufactured by ColorLink Company, which can convert the polarity of the polarized predetermined color light. In this embodiment, the original S The (P) polarized first color light 31 (eg red light) is converted to P(S) polarized.

The first and second polarized light splitting prisms 231 and 232 can vertically reflect S-polarized colored light, and allow P-polarized colored light to directly pass through.

The first-third light valves 241-243 are reflective light valves, which can be modulated and changed to reflect the polarity of the first-third color light 31-33 when they are respectively projected on them. Different polarity shades in opposite directions.

The reflector 25 can be used to reflect light of various colors.

For the convenience of description below, in Fig. 3 and Fig. 4, the first, second, and third color lights that are polarized by S are marked as 311, 321, and 331 respectively, and the first, second, and third colors that are polarized by P The three colored lights are marked as 312, 322, 332 respectively.

In Fig. 2, 3, 4, take the position that the first, second camera lens 26,27 faces as the front and the first, second camera lens 26, 27 points left and right side, illustrate as the direction reference of relative position, That is to say, in terms of configuration, in this embodiment, the S-polarized, rightward white light 3 is projected on the beam splitter 21 arranged obliquely from bottom to upper right, and the S-polarized light reflected vertically upward is separated. The first and second color light 311, 32I, and the third color light 331 which penetrates to the right.

After the S-polarized first color light 311 is reflected upwards by the aforementioned beam splitter 21, as shown in FIG. 221 converts the first color light 311 into P-polarized first color light 312, while the second color light 321 maintains the original S polarization, and then reaches the first polarized beam splitter prism 231 upwards, the first color light 312 It can directly pass through the first polarized light splitter prism 231 and reach the first light valve 241, and after being modulated by the first light valve 241, the downward S-polarized first color light 311 is sent out in the opposite direction, so it can be detected by the first The polarized beam splitting prism 231 reflects vertically and reaches the second polarization selector 222 forward.

After the S-polarized second color light 321 is reflected upward by the beam splitter 21, it continues to pass through the aforementioned first light polarization selector 221. Since the first light polarization selector 221 can only change the polarity of the first color light 31, Therefore, after the second color light 321 passes through the first light polarization selector 221 upwards, it still maintains the original S polarization, and then when the second color light 321 reaches the first polarization beam splitter 231, it is reflected back and reaches the second light valve 242, and after being modulated by the second light valve 242, the forward P-polarized second color light 322 is sent out in the reverse direction, so it can directly pass through the first polarized beam splitting prism 231 forward and arrive at the second light polarization selector 222.

When the aforementioned S-polarized first color light 311 and P-polarized second color light 322 reach the second light polarization selector 222, when the first color light 311 passes through the second light polarization selector 222, its polarity will be changed And become the first color light 312 of P polarization, and the second color light 322 will still maintain its original polarity when passing through the second light polarization selector 222, so it is all P polarization when passing through the first lens 26 at last The first color light 312 and the second color light 322 .

In addition, when the S-polarized third color light 331 passes through the beam splitter 21 shown in FIG. It is reflected upwards to the second polarized light splitter prism 232, and then reflected backwards to the third light valve 243. After being modulated by the third light valve 243, the forward P-polarized second color light 332 is sent out in the opposite direction. , and arrive at the corresponding second lens 27 , so the P-polarized third color light 332 finally passes through the second lens 27 .

In another embodiment of the present invention, the whole double-lens type projection display device 2, since the device 2 is projected forward by the modulated first and second colored light 31, 32 respectively by the first lens 26, and the second colored light is projected forward by the second The lens 27 is for the third color light 33 to project forward, so as long as the single lens (the second lens 27) and the single light valve (the third light valve 243) are adjusted for offset alignment, the image projected forward can be It only needs to overlap with the image projected by the aforementioned first lens 26 , so the alignment is indeed simpler than the three-lens design.

Moreover, the dual-lens projection display device 2 of the present embodiment does not use the light-combining prism and the two-color light-separating prism consisting of four prisms in the components used, so it can reduce the manufacturing difficulty and avoid shifting the frequency spectrum of the predetermined color light. bit.

In addition, in this embodiment, between the above-mentioned second polarizing light splitting prism 232 and the third light valve 243 and between the above-mentioned first polarizing light splitting prism 231 and the first and second light valves 241 and 242, a 1 /4 wave plate (in the present embodiment no longer represented by figure), and can be between the first lens 26 and the second light polarization selector 222 and between the second lens 27 and the second polarization beam splitter prism 232 , each additionally install a polarizer to increase the contrast of each color light. Components such as 1/4 wave plate and polarizing plate that are added here are all general standardized products, so I won’t explain them here.

In view of the above, the present invention can indeed provide a dual-lens projection display device, so that it only needs to adjust the alignment of the single light valve and the single lens, which is simpler than the alignment of the previous three-lens design, and the present embodiment The components used no longer use the light-combining prism and the two-color light-separating prism composed of four prisms in the previous single-lens design, thereby reducing the difficulty of manufacturing and avoiding the shift of the spectrum of the predetermined color light.

Claims (3)

1, a kind of double lens type projection display device, comprise a spectroscope, one first light polarization selector switch, one second light polarization selector switch, one first polar biased light Amici prism, one second polar biased light Amici prism, reflective one the first-the three light valve, a catoptron and be one first camera lens and one second camera lens of isoplanar configured in parallel, and a white light can be isolated first, second, third coloured light that can synthesize described white light, make described the one one three coloured light be subjected to described the first-the three light valve modulation respectively;

It is characterized in that:

Described spectroscope, be used for to be subjected to the white light of predetermined polarization to isolate one and advance and deliver to described first coloured light and described second coloured light of the described first light polarization selector switch, and past another different directions is advanced and delivered to described the 3rd coloured light of described catoptron toward predetermined direction;

The described first light polarization selector switch is used for making aforementioned first, second coloured light to pass through, and changes the polarity of first coloured light;

The described first polar biased light Amici prism, be arranged at the described first light polarization selector switch and export on the direction of first, second coloured light, carry out being sent to the described second light polarization selector switch behind the modulation and respectively first, second coloured light is projected to described first light valve and described second light valve;

The described second light polarization selector switch, for first, second coloured light by the time project in order to the polarity that changes first coloured light and via described first camera lens;

Described catoptron is in order to reflex to the 3rd coloured light the described second polar biased light Amici prism;

The described second polar biased light Amici prism is used for that the 3rd coloured light is projected to described the 3rd light valve and carries out modulation after projected by this second camera lens.

2, double lens type projection display device as claimed in claim 1 is characterized in that: between described second polar biased light Amici prism and the 3rd light valve and between the described first polar biased light Amici prism and first, second light valve, each installs one 1/4 ripple plates.

3, double lens type projection display device as claimed in claim 1 is characterized in that: between described first camera lens and the second light polarization selector switch and between second camera lens and the second polar biased light Amici prism, respectively be equiped with a Polarizer.

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