CN201681249U - Stereoscopic projection device with double liquid crystal light valve and single projector - Google Patents

Abstract

The utility model relates to a stereoscopic projection device with double liquid crystal light valves and a single projector. The stereoscopic projection device comprises a projector, a linear polarizer, two liquid crystal light valves, a synchronous circuit, a screen and circular polarizing glasses. The linear polarizer is arranged at the front of the lens of the projector. A first optical self-compensating bending mode liquid crystal light valve is arranged on the external side of the linear polarizer. One side of the lens of the projector is an internal side. A second optical self-compensating bending mode liquid crystal light valve is arranged on the external side of the first optical self-compensating bending mode liquid crystal light valve. Video input signals are divided into left eye image signals and right eye image signals which are sequentially and alternately transmitted to the screen. Light rays emitted by the projector sequentially pass through the linear polarizer, the first liquid crystal light valve and the second liquid crystal light valve and are projected onto the screen. Audience can wear the polarizing glasses to watch the screen. The utility model has the advantages of simple structure, simple circuit and low cost and overcomes the trouble in the alignment of images projected by two projectors. By using one projector which collaborates with the two liquid crystal light valves and the supporting circuit, the audience can watch stereoscopic projections after the audience wear the polarizing glasses.

Description

Stereoscopic projection device with double liquid crystal light valve and single projector

technical field

The utility model relates to a stereoscopic projection device, in particular to a stereoscopic projection device with double liquid crystal light valves and a single projector, which uses one projector to match two liquid crystal light valves and circular polarized glasses to realize the stereoscopic projection effect.

Background technique

The existing stereoscopic projection technology generally utilizes two projectors, and a fixed left-handed circular polarizer and a right-handed circular polarizer are respectively installed in front of the two lenses to convert the light into left-handed circularly polarized light and right-handed circularly polarized light. Projected on a screen, the audience can watch stereoscopic images after wearing circular polarizer glasses. This method requires precise alignment of two projectors to ensure the accuracy of the projection position, and the use of two projectors at the same time is costly.

Contents of the invention

The purpose of the utility model is to provide a stereoscopic projection device with double liquid crystal light valves and single projector. The polarization state of light is controlled by the liquid crystal light valve to realize the way of projecting stereoscopic images by a single projector. The method of projecting stereoscopic images by a single projector is realized. Compared with the stereoscopic projection device of two projectors, the utility model has simple structure, simple circuit and low cost, and does not need to consider the alignment problem of the projected images of the two projectors. Using a projector with two liquid crystal light valves and supporting circuits, the audience can watch the stereoscopic projection effect by wearing circular polarized glasses.

The stereoscopic projection device with double light valve and single projector provided by the utility model includes a projector, a polarizer, a synchronous circuit, two optical self-compensating bending mode liquid crystal light valves, a screen and circularly polarized glasses:

The projector is used to support video playback with a frame frequency of 100HZ or higher; it adopts DLP technology, LCOS technology, LCD technology, etc.

A linear polarizer is used to generate linearly polarized light; a polarizer with a polarization degree higher than 99% or other linear polarizing devices with equivalent functions are used.

Two optically self-compensating bend-mode liquid crystal light valves for converting linearly polarized light to left-handed circularly polarized light or right-handed circularly polarized light;

Synchronization circuit: used to collect the frame frequency signals of the left and right eye images from the video signal input port, and the two signals are alternately input to the projector for projection to the screen. Simultaneously generate a synchronous waveform signal for driving the liquid crystal light valve;

Polarized glasses: linear polarized glasses, the directions of the transmission axes of the polarizers of the left and right eyes of the linear polarized glasses are perpendicular to each other;

The linear polarizer is located in front of the projector lens, the first optically self-compensating bend-mode liquid crystal light valve is located outside the linear polarizer (the projector lens side is the inner side), and the second optically self-compensating bend-mode liquid crystal light valve is located on the first Optically self-compensating bend mode LCD light valve outside (projector lens side is inside).

The video input signal is divided into left and right eye image signals, which are alternately transmitted to the projector in turn. The light emitted by the projector passes through the linear polarizer, the first liquid crystal light valve, and the second liquid crystal light valve in turn, and is projected onto the screen. Wear circular polarization glasses to watch the screen .

Screen: normal screen or metal screen.

Circular polarizer glasses: The left and right eyes of circular polarizer glasses are left-handed circular polarizers and right-handed circular polarizers respectively.

The linear polarizer, liquid crystal light valve, and synchronous circuit can be used as external additional parts of ordinary projectors, and can also be built in the projector.

The thickness of the liquid crystal layer in the first liquid crystal light valve and the second liquid crystal light valve in the optical self-compensating bending mode (that is, OCB mode, also known as π cell) is less than or equal to 5 microns, which has the characteristics of fast response, and the general rise time is 0.8 milliseconds or less. Fall time 1.5 ms or less.

The projection direction of the long axis of the liquid crystal molecules in the first liquid crystal light valve is 45 degrees or minus 45 degrees to the polarization direction of the linear polarizer 2 . The projection direction of the long axis of the liquid crystal molecules in the second liquid crystal light valve 5 and the first liquid crystal light valve is perpendicular to each other, and the specific positional relationship is shown in FIG. 2 and FIG. 3 .

The synchronous circuit 3 can generate two voltage signals A and B, and A and B are respectively applied to the first liquid crystal light valve and the second liquid crystal light valve at the same time, that is, when the voltage applied to the first liquid crystal light valve is A , the voltage applied to the second liquid crystal light valve is B; when the voltage applied to the first liquid crystal light valve is B, the voltage applied to the second liquid crystal light valve is A.

In the voltage signal generated by the synchronous circuit 3, A is a high voltage, generally higher than 10V; B is an appropriate voltage lower than 10V, the voltage value is generally between 3V and 10V, and the typical high voltage value is 6V to 7V, which is used to maintain the first The retardation of one liquid crystal light valve or the second liquid crystal light valve is about 1/4 wavelength, and the specific voltage depends on factors such as parameters of the liquid crystal material itself.

The synchronization circuit can detect the frame rate signals of the left and right eye images at the video input end. When the left and right eye images are changed, the voltage signals A and B generated by the synchronization circuit alternate synchronously.

The left and right eyes in the circularly polarized glasses are left-handed circular polarizers and right-handed circular polarizers respectively, and the left and right eye polarizers on the glasses are interchangeable.

The utility model provides a stereoscopic projection device with double liquid crystal light valves and a single projector. The polarization state of light is controlled by the liquid crystal light valve, and the way of projecting a stereoscopic image by a single projector is realized. Compared with the stereoscopic projection device with two projectors , The utility model has the advantages of simple structure, simple circuit and low cost, and there is no need to consider the alignment problem of the projected images of the two projectors. Using a projector with two liquid crystal light valves and supporting circuits, the audience can watch the stereoscopic projection effect by wearing circular polarized glasses.

Description of drawings:

Figure 1: The composition and optical path of a stereoscopic projection device with dual liquid crystal light valves and single projector.

FIG. 2 : Relative position relationship 1 of the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 .

FIG. 3 : the second relative positional relationship between the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 .

FIG. 4 : The relative positional relationship among the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 is obtained when right-handed circularly polarized light is obtained.

FIG. 5 : The relative positional relationship of the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 1. Obtaining left-handed circularly polarized light.

FIG. 6 : Obtaining left-handed circularly polarized light when the relative positional relationship between the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 is second.

FIG. 7 : Obtaining right-handed circularly polarized light when the relative positional relationship between the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 is two.

Detailed ways

The utility model is described in detail as follows with reference to accompanying drawing:

Figure 1: The structure and optical path of the stereoscopic projection device with dual liquid crystal light valves and single projector, and the arrows in solid lines indicate the direction of light propagation.

FIG. 2 : Relative position relationship 1 of the linear polarizer 2 , the liquid crystal light valve 4 (the first liquid crystal light valve) and the liquid crystal light valve 5 (the second liquid crystal light valve). The polarization direction of the linear polarizer 2 is 8, the projection direction of the long axis of the liquid crystal molecules of the liquid crystal light valve 4 is 9, and the projection direction of the long axis of the liquid crystal molecules of the liquid crystal light valve 5 is 10. The angle between direction 9 and direction 8 is 45 degrees, and direction 9 and direction 10 are perpendicular.

FIG. 3 : the second relative positional relationship between the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 . The polarization direction of the linear polarizer 2 is 8, the projection direction of the long axis of the liquid crystal molecules of the liquid crystal light valve 4 is 10, the projection direction of the long axis of the liquid crystal molecules of the liquid crystal light valve 5 is 9, the angle between the direction 9 and the direction 8 is 45 degrees, and the direction 9 and the direction 10 vertical.

FIG. 4 : The relative positional relationship among the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 is obtained when right-handed circularly polarized light is obtained. The voltage applied to the liquid crystal light valve 4 is A, and the voltage applied to the liquid crystal light valve 5 is B.

FIG. 5 : The relative positional relationship of the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 1. Obtaining left-handed circularly polarized light. The voltage applied to the liquid crystal light valve 4 is B, and the voltage applied to the liquid crystal light valve 5 is A.

FIG. 6 : Obtaining left-handed circularly polarized light when the relative positional relationship between the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 is second. The voltage applied to the liquid crystal light valve 4 is A, and the voltage applied to the liquid crystal light valve 5 is B.

FIG. 7 : Obtaining right-handed circularly polarized light when the relative positional relationship between the linear polarizer 2 , the liquid crystal light valve 4 and the liquid crystal light valve 5 is two. The voltage applied to the liquid crystal light valve 4 is B, and the voltage applied to the liquid crystal light valve 5 is A.

Operating principle and process:

This double liquid crystal light valve single projector stereoscopic projection device uses two superimposed liquid crystal light valves to control the optical polarization state of the output light of the projector. Separation, so as to achieve stereoscopic effect.

The video input signal 1A required by the dual-liquid crystal light valve single-projector stereoscopic projection device is divided into a left-eye image and a right-eye image, and the left-eye image and the right-eye image are cyclically and alternately transmitted to the projector 1 .

The light emitted from the projector 1 becomes linearly polarized light 11 after passing through the linear polarizer 2 , and its polarization direction is consistent with that of the linear polarization 2 .

Both liquid crystal light valves 4 and 5 adopt OCB mode liquid crystal light valves (OCB is an optical self-compensating bending mode, also called π cell), and the thickness of the cell is less than or equal to 5 microns, which has the characteristics of fast response, and the general rise time is 0.8 milliseconds or less. Fall time 1.5 ms or less. The characteristics of fast response of the OCB mode liquid crystal light valve can ensure that the optical polarization state of the output light of the projection device is changed correspondingly when the image is switched at a high speed.

The angle between the projected direction of the long axis of the liquid crystal molecules in the liquid crystal light valve 4 and the polarization direction of the polarizer 2 is 45 degrees or minus 45 degrees. The projection direction of the long axis of the liquid crystal molecules in the liquid crystal light valve 5 is perpendicular to the projection direction of the long axis of the liquid crystal molecules in the liquid crystal light valve 4 . That is, there are two combinations of the polarization direction of the polarizer 2, the projection direction of the long axis of the liquid crystal molecules in the liquid crystal light valve 4, and the projection direction of the long axis of the liquid crystal molecules in the liquid crystal light valve 5, as shown in Figures 2 and 3. Either way.

The relative positions of the linear polarizer 2, the liquid crystal light valve 4 and the liquid crystal light valve 5 are momentary, as shown in Fig. 2. The working mode of the projection system is as follows:

State 1: see Fig. 4, when a high voltage A is applied to the liquid crystal light valve 4, the residual retardation of the liquid crystal light valve 4 is close to zero, and has no modulation effect on polarized light. The linearly polarized light 11 passes through the liquid crystal light valve 4 without changing the optical polarization state. At this time, the voltage applied to the liquid crystal light valve 5 is B, and the retardation of the liquid crystal light valve 5 is about 1/4 wavelength. At this time, the liquid crystal light valve 5 functions as a 1/4 wave plate. The linearly polarized light 11 becomes right-handed circularly polarized light 12 after passing through the liquid crystal light valve 5 .

State 2: see Fig. 5, when the voltage applied to the liquid crystal light valve 4 is B, the retardation of the liquid crystal light valve 4 is about 1/4 wavelength, and at this moment, the function of the liquid crystal light valve 4 is equivalent to a 1/4 wave plate, and the line The polarized light 11 becomes left-handed circularly polarized light 13 after passing through the liquid crystal light valve 4 . At this time, the voltage applied to the liquid crystal light valve 5 is A, the residual retardation of the liquid crystal light valve 5 is close to zero, and has no modulation effect on polarized light.

When the video input signal image is converted from the left-eye image to the right-eye image or from the right-eye image to the left-eye image, the synchronous circuit 3 controls the output voltage signals A and B, and switches state one and state two accordingly to ensure that the left The eye image is separated from the right eye image and kept in sync with the frame rate of the video input signal 1A.

The relative positional relationship between the linear polarizer 2, the liquid crystal light valve 4 and the liquid crystal light valve 5 is shown in Fig. 3. The working mode of the projection system is as follows:

State 1: see Fig. 6, when a high voltage A is applied to the liquid crystal light valve 4, the residual retardation of the liquid crystal light valve 4 is close to zero, and has no modulation effect on polarized light. The linearly polarized light 11 passes through the liquid crystal light valve 4 without changing the optical polarization state. At this time, the voltage applied to the liquid crystal light valve 5 is B, and the retardation of the liquid crystal light valve 5 is about 1/4 wavelength. At this time, the liquid crystal light valve 5 functions as a 1/4 wave plate. The linearly polarized light 11 becomes left-handed circularly polarized light 13 after passing through the liquid crystal light valve 5 . see picture

State 2: As shown in Figure 7, when the voltage applied to the liquid crystal light valve 4 is B, the retardation of the liquid crystal light valve 4 is about 1/4 wavelength. The polarized light 11 becomes right-handed circularly polarized light 12 after passing through the liquid crystal light valve 4 . At this time, the voltage applied to the liquid crystal light valve 5 is A, the residual retardation of the liquid crystal light valve 5 is close to zero, and has no modulation effect on polarized light, and the right-handed circularly polarized light 12 is still right-handed circularly polarized light after passing through the liquid crystal light valve 5 12.

When the image of the video input signal is converted from the left-eye image to the right-eye image or from the right-eye image to the left-eye image, the synchronous circuit 3 controls the output voltage signals A and B, and switches state one and state two accordingly to ensure that the left The eye image is separated from the right eye image and kept in sync with the frame rate of the video input signal 1A.

Through synchronous conversion with the input video signals separated from the left and right eyes, the images of the left and right eyes are projected onto the screen sequentially according to the left-handed circularly polarized light or the right-handed circularly polarized light in time division. The audience is located in front of the screen 6 and wears circular polarizing glasses 7 . The left and right eyes are left-handed circular polarizers and right-handed circular polarizers respectively, and the left and right eyes can only distinguish one of left-handed circularly polarized light and right-handed circularly polarized light images. In this way, the separation of the left-eye image and the right-eye image is realized, and a stereoscopic display effect is realized.

Claims (8)

1. A kind of double liquid crystal light valve single projector three-dimensional projection device, it is characterized in that comprising: Projectors to support video playback with a frame frequency of 100HZ or higher; a linear polarizer for generating linearly polarized light; Two optically self-compensating bend-mode liquid crystal light valves for converting linearly polarized light to left-handed circularly polarized light or right-handed circularly polarized light; Synchronization circuit: used to collect the frame frequency signals of the left and right eye images from the video signal input port, and simultaneously generate a synchronous voltage signal for driving the liquid crystal light valve; Polarized glasses: linear polarized glasses, the directions of the transmission axes of the polarizers of the left and right eyes of the linear polarized glasses are perpendicular to each other; The linear polarizer is located in front of the projector lens, the first optically self-compensating bend-mode liquid crystal light valve is located outside the linear polarizer, the projector lens side is on the inside, and the second optically self-compensating bend-mode liquid crystal light valve is located on the first optical The self-compensating bend mode LCD light valve is on the outside and the projector lens side is on the inside. 2. The stereoscopic projection device according to claim 1, characterized in that: said linear polarizer, liquid crystal light valve, and synchronous circuit can be used as external additional parts of a common projector, or can be built inside the projector. 3. The stereoscopic projection device according to claim 1, characterized in that: the thickness of the liquid crystal layer in the first liquid crystal light valve and the second liquid crystal light valve is less than or equal to 5 microns; response time: rise time 0.8 milliseconds or less, fall time 1.5 milliseconds or less. 4. stereoscopic projection device according to claim 1, is characterized in that: in the first liquid crystal light valve, liquid crystal molecule long-axis projection direction and linear polarizer (2) polarizing direction become 45 degree or negative 45 degree; The projection direction of the long axis of the liquid crystal molecules in the valve and the first liquid crystal light valve is perpendicular to each other. 5. The stereoscopic projection device according to claim 1, characterized in that: the synchronous circuit can generate two voltage signals, high voltage A and low voltage B, and A and B are respectively added to the first liquid crystal light valve and the second liquid crystal light valve at the same time. On the second liquid crystal light valve, that is, when the voltage applied to the first liquid crystal light valve is A, the voltage applied to the second liquid crystal light valve is B; when the voltage applied to the first liquid crystal light valve is B, the second liquid crystal light valve The voltage applied to the valve is A. 6. The stereoscopic projection device according to claim 5, characterized in that: the high voltage is higher than 10V; the low voltage is 3V to 10V. 7. The stereoscopic projection device according to claim 5, characterized in that: the synchronization circuit detects the frame rate signals of the left and right eye images at the video input end, and when the left and right eye images are replaced, the voltage signal A and B generated by the synchronization circuit are synchronized alternately. 8. The stereoscopic projection device according to claim 1, wherein the left eye and the right eye in the polarized glasses are left-handed circular polarizers and right-handed circular polarizers respectively, and the left and right eye polarizers on the glasses are interchangeable. the

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