Projector optical system

Abstract

The application discloses a projector optical system, which comprises a light source, a first compensation element, a second compensation element and a screen, wherein the first compensation element is arranged on the light exit side of the light source and is used for compensating the phase difference of the light emitted by the light source in a first direction, the first direction being the direction of the light emitted by the light source passing through the first compensation element; the second compensation element is arranged on the light exit side of the first compensation element and is used for compensating the phase difference of the light emitted by the first compensation element in a second direction, the second direction being the direction perpendicular to the first direction; and the light emitted by the second compensation element is projected onto the screen.

Description

Technical Field

[0001] This application relates to the field of projection display technology, and in particular to a projector optical system. Background Technology

[0002] With changing entertainment needs, projectors, as large-screen projection devices, are increasingly used in daily life. In related technologies, projector optical systems compensate for light by using quarter-wave plates (QWPs). However, since QWPs can only partially compensate for light, these optical systems suffer from light leakage over wide viewing angles. Summary of the Invention

[0003] This application discloses a projector optical system that can solve the problem of light leakage at a large viewing angle in projector optical systems.

[0004] To solve the above problems, this application adopts the following technical solution:

[0005] This application discloses a projector optical system, including: a light source, a first compensation element, a second compensation element, and a screen, wherein: the first compensation element is disposed on the light-emitting side of the light source and is used to compensate for the phase difference of the emitted light from the light source in a first direction, wherein the first direction is the direction in which the emitted light from the light source passes through the first compensation element; the second compensation element is disposed on the light-emitting side of the first compensation element and is used to compensate for the phase difference of the emitted light from the first compensation element in a second direction, wherein the second direction is a direction perpendicular to the first direction; the emitted light from the second compensation element is projected onto the screen.

[0006] This application provides a projector optical system. By providing a first compensation element on the light-emitting side of the light source to compensate for the phase difference of the emitted light in a first direction as it passes through the first compensation element, and a second compensation element on the light-emitting side of the first compensation element to compensate for the phase difference in a second direction perpendicular to the first direction, the light emitted from the light source passes through the first compensation element and the second compensation element in sequence and is projected onto the screen, thus avoiding light leakage at a large viewing angle in the projector optical system. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the structure of a projector optical system disclosed in an embodiment of this application;

[0008] Figure 2 This is a schematic diagram of the structure of a projector optical system disclosed in an embodiment of this application. Detailed Implementation

[0009] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0010] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0011] Figure 1 This is a schematic diagram of the structure of a projector optical system disclosed in an embodiment of this application. Figure 2 This is a schematic diagram of the structure of a projector optical system disclosed in an embodiment of this application.

[0012] like Figure 1 and Figure 2 As shown, the projector optical system disclosed in this application includes: a light source 110, a first compensation element 120, a second compensation element 130, and a screen 140, wherein: the first compensation element 120 is disposed on the light-emitting side of the light source 110 and is used to compensate for the phase difference of the emitted light from the light source 110 in a first direction, wherein the first direction is the direction in which the emitted light from the light source 110 passes through the first compensation element 120; the second compensation element 130 is disposed on the light-emitting side of the first compensation element 120 and is used to compensate for the phase difference of the emitted light from the first compensation element 120 in a second direction, wherein the second direction is a direction perpendicular to the first direction; the emitted light from the second compensation element 130 is projected onto the screen 140.

[0013] In this application, the first direction is the direction in which the emitted light from the light source 110 passes through the first compensation element 120, that is, the first direction is the thickness direction of the first compensation element 120, and the second direction is the direction perpendicular to the thickness direction of the first compensation element 120.

[0014] In this application, the light emitted by the light source 110 passes sequentially through a first compensation element 120 for compensating the phase difference of the emitted light from the light source 110 in a first direction, and a second compensation element 130 for compensating the phase difference of the emitted light from the first compensation element 120 in a second direction perpendicular to the first direction, and is then projected onto the screen 140, which can solve the problem of light leakage at a large viewing angle in the projector optical system.

[0015] This application provides a projector optical system. By providing a first compensation element 120 on the light-emitting side of the light source 110 to compensate for the phase difference of the emitted light from the light source 110 in a first direction as it passes through the first compensation element 120, and a second compensation element 130 on the light-emitting side of the first compensation element 120 to compensate for the phase difference in a second direction perpendicular to the first direction, the light emitted from the light source 110 passes through the first compensation element 120 and the second compensation element 130 in sequence and is projected onto the screen 140, thus avoiding light leakage from the projector optical system at large viewing angles.

[0016] In one implementation, such as Figure 1 and Figure 2 As shown, the above-mentioned projector optical system may further include a reflector cup 150, a first lens 160, a reflective polarizer 170, a polarizer 180, and a display 190, wherein: the reflector cup 150 is disposed on the light-emitting side of the light source 110, the first lens 160 is disposed on the light-emitting side of the reflector cup 150, the first compensation element 120 is disposed on the light-emitting side of the first lens 160, the reflective polarizer 170 is disposed on the light-emitting side of the second compensation element 130, the polarizer 180 is disposed on the light-emitting side of the reflective polarizer 170, and the display 190 is disposed on the light-emitting side of the polarizer 180, and the emitted light from the display 190 is projected onto the screen 140.

[0017] The emitted light from the light source 110 is dispersed by the reflector cup 150 to the first lens 160. The first lens 160 collimates the emitted light from the light source 110 into multiple parallel beams. These multiple parallel beams pass sequentially through the first compensation element 120, the second compensation element 130, and the reflective polarizer 170 to reach the polarizer 180. The polarizer 180 decomposes the multiple parallel beams into P-beams and S-beams. The P-beams pass through the display 190 and are projected onto the screen 140. The S-beams are reflected back to the second compensation element 130 by the reflective polarizer 170. Since the second compensation element 130 also rotates the transmission axis of the S-beams by 90°, converting the S-beams into right-hand circularly polarized light, the S-beams are converted into right-hand circularly polarized light after passing through the second compensation element 130. The circularly polarized light is first passed through the first compensation element 120 and the first lens 160 to the reflector cup 150, and then reflected by the reflector cup 150 to be converted into left-hand circularly polarized light. The left-hand circularly polarized light then passes through the first lens 160 and the first compensation element 120 to the second compensation element 130. Since the second compensation element 130 is also used to convert the left-hand circularly polarized light into P-light, the left-hand circularly polarized light passes through the second compensation element 130 and is converted into P-light. Since the transmission axis of the converted P-light is consistent with the transmission axis of the reflective polarizer 170, the converted P-light can pass through the reflective polarizer 170 and then continue to pass through the display 190 and be projected onto the screen 140, which can effectively improve the utilization rate of the light source 110.

[0018] In another possible implementation, the reflector 150 is disposed on the light-emitting side of the light source 110, the first compensation element 120 is disposed on the light-emitting side of the reflector 150, the reflective polarizer 170 is disposed on the light-emitting side of the second compensation element 130, the polarizer 180 is disposed on the light-emitting side of the reflective polarizer 170, the first lens 160 is disposed on the light-emitting side of the polarizer 180, and the display 190 is disposed on the light-emitting side of the first lens 160. The light emitted from the display 190 is projected onto the screen 140. In this case, the light processing by the polarizer 180, the reflective polarizer 170, the second compensation element 130, and the reflector 150 is consistent with that described above, and will not be repeated here.

[0019] In the embodiments of this application, such as Figure 2As shown, the projector optical system described above may further include a second lens 1110, a reflector 1120, and a lens 1130. The second lens 1110 is disposed on the light-emitting side of the display 190. The light emitted from the second lens 1110 is reflected by the reflector 1120 to the lens 1130, and finally projected onto the screen 140, where an image is formed. It should be noted that both the first lens 160 and the second lens 1110 are used to convert divergent light into a collimated beam, resulting in uniformly emitted light.

[0020] In one implementation, the reflector cup 150 can be a frustum-shaped or frustum-shaped reflector cup.

[0021] In one implementation, both the first lens 160 and the second lens 1110 can be Fresnel lenses to reduce costs. The surface of the first lens 160 away from the reflector cup 150 is flat, and the surface of the second lens 1110 near the display 190 is flat. Furthermore, a first anti-reflective coating can be provided on the flat surface of the Fresnel lens. For example, the first anti-reflective coating can be an anti-reflective film, meaning that an anti-reflective film is added to the flat surface of the Fresnel lens, i.e., AR surface treatment is applied to the flat surface of the Fresnel lens to improve the light efficiency of the projector's optical system. In addition, the first lens 160 and the second lens 1110 can also be other lenses capable of achieving the corresponding functions; this application does not specifically limit their applications.

[0022] In one implementation, the reflective polarizer 170 can be a reflective polarizer (RP) or a dual brightness enhancement film (DBEF). The reflective polarizer 170 described herein can also be other reflective polarization structures, which are not specifically limited in this application.

[0023] In one implementation, the polarizer 180 can be a polarizer (POL).

[0024] In one implementation, the display 190 can be a liquid crystal display (LCD).

[0025] In this embodiment, the projector optical system described above may further include a heat-insulating glass 1100, which is disposed between the light source 110 and the first compensation element 120. By disposing the heat-insulating glass 1100 on the light-emitting side of the light source 110, the heat generated by the light source 110 can be prevented from affecting the entire projector optical system.

[0026] In one implementation, the above-described projector optical system may further include a second anti-reflection and anti-glare member disposed on the surface of the heat-insulating glass 1100. Exemplarily, the second anti-reflection and anti-glare member may be an anti-reflection and anti-glare film. That is, an anti-reflection and anti-glare film is added to the surface of the heat-insulating glass 1100, that is, the surface of the heat-insulating glass 1100 is subjected to AR surface treatment to improve the light efficiency of the projector optical system.

[0027] In a possible implementation, the first compensating element 120 is a C plate, and the second compensating element 130 is a quarter-wave plate.

[0028] Exemplarily, the quarter-wave plate (QWP) may be a reverse wavelength dispersion (RWD) QWP. This QWP is a retardation film coated with liquid crystal, the pretilt angle of the liquid crystal is 0°, and the refractive index of the film is nx < ny = nz. It should be noted that the QWP is a retardation film with the optical axis parallel to the film surface, that is, an A plate.

[0029] Exemplarily, the C plate may be an RWD C plate. This C plate is a retardation film coated with liquid crystal, the pretilt angle of the liquid crystal is 90°, and the refractive index of the film is nx = ny > nz. Since the C plate can compensate for oblique leakage light in the dark state to expand the viewing angle, therefore, by using the C plate as the compensation film for the quarter-wave plate, the problem of large viewing angle leakage light of the projector optical system can be solved. It should be noted that the optical axis of the C plate is perpendicular to the film surface.

[0030] In one implementation, the quarter-wave plate may be a wide-waveband quarter-wave plate, which can allow more light to pass through and improve the light efficiency of the projector optical system. Of course, the QWP may also be a narrow-waveband QWP, and the present application does not make specific limitations on this.

[0031] In the embodiments of the present application, the light source 110 may be a light-emitting diode (LED) light source. The LED light source includes a heat-conducting substrate provided with a light-emitting area, and a plurality of light-emitting wafers are installed in the light-emitting area. In one implementation, a plurality of reflectors may be disposed in the gaps between the plurality of light-emitting wafers, and the light in the gaps between the plurality of light-emitting wafers is reflected by the reflectors to the reflecting light cup 150, so as to improve the illumination efficiency of the light source 110 and save power consumption. Exemplarily, the reflector may be a reflective film.

[0032] The above embodiments of this application focus on describing the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be described in detail here.

[0033] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A projector optical system, characterized in that, include: The light source, the first compensation element, the second compensation element, and the screen, wherein: The first compensation element is disposed on the light-emitting side of the light source and is used to compensate for the phase difference of the emitted light of the light source in a first direction, wherein the first direction is the direction in which the emitted light of the light source passes through the first compensation element. The second compensation element is disposed on the light-emitting side of the first compensation element and is used to compensate for the phase difference of the emitted light of the first compensation element in a second direction, wherein the second direction is a direction perpendicular to the first direction. The emitted light from the second compensation element is projected onto the screen; It also includes a reflector cup, a first lens, a reflective polarizer, a polarizer, and a display, wherein: The emitted light from the light source is dispersed through the reflector cup to the first lens. The first lens collimates the emitted light from the light source into multiple parallel beams. The multiple parallel beams pass sequentially through the first compensation element, the second compensation element, and the reflective polarizer to reach the polarizer. The polarizer decomposes the multiple parallel beams into P-beams and S-beams. The P-beams pass through the display and are projected onto the screen. The S-beams are reflected back to the second compensation element by the reflective polarizer. The S-beams pass through the second compensation element and are converted into right-hand circularly polarized light. The right-hand circularly polarized light passes sequentially through the first compensation element and the first lens to reach the reflector cup, and is reflected by the reflector cup to be converted into left-hand circularly polarized light. The left-hand circularly polarized light passes sequentially through the first lens and the first compensation element to reach the second compensation element, and is converted into P-beams by the second compensation element.

2. The projector optical system according to claim 1, characterized in that, The first lens is a Fresnel lens.

3. The projector optical system according to claim 2, characterized in that, It also includes a first anti-reflective anti-reflective element, which is disposed on the flat surface of the Fresnel lens.

4. The projector optical system according to claim 1, characterized in that, It also includes heat-insulating glass, which is disposed between the light source and the first compensation element.

5. The projector optical system according to claim 4, characterized in that, It also includes a second anti-reflective anti-reflective element, which is disposed on the surface of the heat-insulating glass.

6. The projector optical system according to claim 1, characterized in that, The first compensation element is a C plate.

7. The projector optical system according to claim 1, characterized in that, The second compensation element is a quarter-wave plate.

8. The projector optical system according to claim 7, characterized in that, The quarter-wave plate is a wide-band quarter-wave plate.

9. The projector optical system according to claim 1, characterized in that, It also includes a reflector disposed in the gap of the light-emitting wafer of the light source.

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