TWI864286B - Laser light source depolarizer and projection device having the same - Google Patents

Abstract

A laser light source depolarizer includes a laser light source, a light angle adjusting element, a birefringent crystal, and an integration rod. The laser light source is configured to emit a laser light. The light angle adjusting element is configured to change the diffusion angle of the laser light. The light angle adjusting element is disposed between the laser light source and the birefringent crystal. The birefringent crystal is disposed between the light angle adjusting element and the integration rod, and the birefringent crystal is configured to break the polarity of the laser light.

Description

Laser light source depolarizer and projector device having the same

The present disclosure relates to a laser light source depolarizer and a projector device having the laser light source depolarizer.

Most current laser light source projectors use independent optical systems for optical coupling, combining laser light sources of different colors into a single optical axis.

Since laser light is polarized light, if it is used in a rear projection structure, it is easy for the internal stress of the screen of the rear projection structure to cause color blocks when the laser light passes through. If the laser light source is used in polarized 3D glasses, it is easy for the viewer to perceive the uneven polarization of the light, resulting in color blocks in vision.

In view of this, how to provide a laser light source for a projector system that can solve the above problems is still one of the goals that the industry urgently needs to study.

One technical aspect of the present disclosure is a laser light source depolarizer.

In one embodiment of the present disclosure, a laser light source depolarizer includes a laser light source, a beam angle adjustment element, a birefringent crystal, and an integrator. The laser light source is configured to emit laser light. The beam angle adjustment element is configured to change the divergence angle of the laser light. The beam angle adjustment element is located between the laser light source and the birefringent crystal. The birefringent crystal is located between the beam angle adjustment element and the integrator, and the birefringent crystal is configured to destroy the polarity of the laser light.

In an embodiment of the present disclosure, a surface of the birefringent crystal facing the beam angle adjustment element and a surface of the birefringent crystal facing the integrator are parallel to each other.

In one embodiment of the present disclosure, the birefringent crystal is formed in one piece.

In an embodiment of the present disclosure, the beam angle adjustment element is a diffuser or a lens.

In one embodiment of the present disclosure, the laser light source depolarizer further includes an optical glue layer located between the beam angle adjustment element and the birefringent crystal.

In one embodiment of the present disclosure, an optical adhesive layer contacts a birefringent crystal.

In one embodiment of the present disclosure, the laser light source depolarizer further includes an optical glue layer located between the birefringent crystal and the integrator.

In one embodiment of the present disclosure, the birefringent crystal has an anti-reflection film.

In an embodiment of the present disclosure, a surface of the birefringent crystal facing the beam angle adjustment element and a surface of the birefringent crystal facing the integrator have an angle.

Another technical aspect of the present disclosure is a projector device.

In an embodiment of the present disclosure, a projector device includes a laser depolarizer, a screen, and a projection module. The screen has a projection surface and a viewing surface located on opposite sides. The projection module receives light from the integrator and converts the light into an image and projects it onto the screen. The projection module is located on the projection surface of the screen.

In the above embodiment, the laser light source depolarizer reduces the light collimation of the laser light through the beam angle adjustment element to increase the diffusion angle of the laser light, and destroys the light polarization of the laser light through the birefringent crystal. Then, the laser light is uniformed through the integrator. In this way, the laser light after passing through the integrator can be suitable for application in projector equipment, such as rear projection architecture or polarized 3D glasses. Because the laser light source depolarizer destroys the light collimation and light polarization of the laser light, the uniformity of the display image can be improved, color blocks can be reduced, and the quality of the projected image can be improved.

The following will disclose multiple embodiments of the present invention with drawings. For the purpose of clarity, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is to say, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings, some commonly used structures and components will be depicted in the drawings in a simple schematic manner. And for the sake of clarity, the thickness of the layers and regions in the drawings may be exaggerated, and the same element symbols represent the same elements in the description of the drawings.

FIG. 1 is a schematic diagram of a laser light source depolarizer 100 according to an embodiment of the present disclosure. The laser light source depolarizer 100 includes a laser light source 110, a beam angle adjustment element 120, a birefringent crystal 130, and an integrator 140. The laser light source 110 is configured to emit laser light L1. The beam angle adjustment element 120 is configured to change the divergence angle θ of the laser light L1. The beam angle adjustment element 120 is located between the laser light source 110 and the birefringent crystal 130. The birefringent crystal 130 is located between the beam angle adjustment element 120 and the integrator 140.

The beam angle adjustment element 120 is configured to change the traveling direction of the laser light L1. In other words, the beam angle adjustment element 120 can increase the diffusion angle θ of the laser light L1 to destroy the collimation of the laser light L1. The beam angle adjustment element 120, the birefringent crystal 130 and the integrator 140 are arranged in the traveling direction of the laser light L1, that is, the first direction D1 in the figure. The birefringent crystal 130 is configured to destroy the polarity of the laser light L2 after passing through the beam angle adjustment element 120. The integrator 140 is configured to uniformly transmit the laser light L3 after passing through the birefringent crystal 130 to the projection module of the projector device.

In one embodiment, the beam angle adjustment element 120 may be a diffuser. In other embodiments, the beam angle adjustment element 120 may be a lens. For example, the beam angle adjustment element 120 may be a Fresnel lens or lenses with different refractive powers, as long as it is an optical element that can increase the diffusion angle θ of the laser light L1 to destroy the collimation of the laser light L1.

In the present embodiment, the laser light L2 after passing through the beam angle adjustment element 120 has different traveling directions, so that the laser light L2 has different optical path differences when entering the birefringent crystal 130. Therefore, in the present embodiment, the surface 132 of the birefringent crystal 130 facing the beam angle adjustment element 120 and the surface 134 of the birefringent crystal 130 facing the integrator 140 may be parallel to each other. In other words, the birefringent crystal 130 in the present embodiment does not need to have an oblique angle. In addition, the birefringent crystal 130 in the present embodiment is formed in one piece. In some embodiments, the surface 132 of the birefringent crystal 130 facing the beam angle adjustment element 120 may have a coating, such as an anti-reflection coating (AR coating), to reduce the probability of the laser light L2 being reflected and improve the transmittance of the laser light L2. In some embodiments, the laser light source depolarizer 100 further includes a lens (not shown) for converging light, which is disposed between the birefringent crystal 130 and the integrator 140, but the present disclosure is not limited thereto.

According to the above, the laser light source depolarizer 100 disclosed in the present invention reduces the light collimation of the laser light L1 through the beam angle adjustment element 120 to increase the diffusion angle θ of the laser light L1, and destroys the light polarization of the laser light L2 through the birefringent crystal 130. Then, the laser light L3 is uniformed through the integrator 140. In this way, the laser light L4 after passing through the integrator 140 can be suitable for application in the projector device. Specifically, the projector device using multi-color laser light can first allow each color laser light source to pass through the laser light source depolarizer 100 before performing the optical coupling operation.

FIG. 2 is a schematic diagram of the laser light source depolarizer 100 of FIG. 1 being applied to the projector device 10. The projector device 10 includes the laser light source depolarizer 100 and the projection system 200. As described in FIG. 1, the laser light L4 passes through the beam angle adjustment element 120, the birefringent crystal 130 and the integrator 140 in sequence and travels to the projection system 200. In this embodiment, the projector device 10 is applied in a rear projection architecture. The projection system 200 receives the laser light L4 from the integrator 140, and converts the laser light L4 into a projection image and projects it onto the thin screen 300, and the viewer 400 and the projector device 10 are located on opposite sides of the thin screen 300, such as the projection surface 304 and the viewing surface 302.

During the manufacturing process of the thin screen 300, internal stress may be generated due to heating and other processes. When the laser light with high collimation and single polarization passes through, it will produce uneven absorption effect and cause color blocks to appear on the display screen. Therefore, by destroying the light collimation and polarization of the laser light by the laser light source depolarizer 100, the uniformity of the display screen can be improved, the color blocks can be reduced, and the quality of the projected screen can be improved.

In some other embodiments, the laser light source depolarizer 100 can also be applied to a projection device that is used with polarized 3D glasses. Since laser light has high polarization, viewers can easily perceive uneven light polarization through polarized 3D glasses. Therefore, by destroying the light collimation and light polarization of the laser light through the laser light source depolarizer 100, the uniformity of the displayed image can be improved, color blocks can be reduced, and the quality of the projected image can be improved.

FIG. 3 is a schematic diagram of a laser light source depolarizer 100a according to another embodiment of the present disclosure. The laser light source depolarizer 100a is substantially the same as the laser light source depolarizer 100 shown in FIG. 1, except that the laser light source depolarizer 100a further includes an optical adhesive layer 150 located between the beam angle adjustment element 120 and the birefringent crystal 130. In this embodiment, the optical adhesive layer 150 bonds the beam angle adjustment element 120 and the birefringent crystal 130. In other words, the optical adhesive layer 150 contacts the surface 132a of the birefringent crystal 130. The optical adhesive layer 150 can reduce the interface reflection of the laser light L2, so the surface 132a of the birefringent crystal 130a does not need to have the aforementioned anti-reflection film. In addition, since the optical adhesive layer 150 can have a thinner thickness, the effect of light loss can be avoided.

In this embodiment, the laser light source depolarizer 100a further includes an optical adhesive layer 160 between the birefringent crystal 130 and the integrator 140. The optical adhesive layer 160 bonds the birefringent crystal 130 and the integrator 140. In some embodiments, the laser light source depolarizer 100a may also only have the optical adhesive layer 160 without the optical adhesive layer 150. The laser light source depolarizer 100a has the same technical effects as the laser light source depolarizer 100 shown in FIG. 1, and will not be described in detail here.

FIG. 4 is a schematic diagram of a laser light source depolarizer 100b according to another embodiment of the present disclosure. The laser light source depolarizer 100b is substantially the same as the laser light source depolarizer 100 shown in FIG. 1, except that the birefringent crystal 130b of the laser light source depolarizer 100b is wedge-shaped. The surface 132a and the surface 134a of the birefringent crystal 130b have an angle. In other words, the birefringent crystal 130b can cause the laser light L2 to further form an optical path difference to destroy the optical polarization of the laser light L2. The laser light source depolarizer 100b may also have a lens (not shown) for converging light, which is disposed between the birefringent crystal 130b and the integrator 140, but the present disclosure is not limited thereto.

FIG. 5 is a schematic diagram of a laser light source depolarizer 100c according to another embodiment of the present disclosure. The laser light source depolarizer 100c is substantially the same as the laser light source depolarizer 100b shown in FIG. 4, except that the birefringent crystal 130c of the laser light source depolarizer 100c is composed of two wedge-shaped birefringent materials 136 and 138. The birefringent materials 136 and 138 cooperate with each other to further form an optical path difference for the laser light L2, and to keep the diffusion angle θ of the laser light L2 unchanged after passing through the birefringent crystal 130c, so as to destroy the optical polarization of the laser light L2. The laser light source depolarizer 100c may also have a lens (not shown) for converging light, which is disposed between the birefringent crystal 130c and the integrator 140, but the present disclosure is not limited thereto.

In summary, the laser light source depolarizer disclosed in the present invention reduces the light collimation of the laser light through the beam angle adjustment element to increase the diffusion angle of the laser light, and destroys the light polarization of the laser light through the birefringent crystal. Then, the laser light is uniformed through the integrator. In this way, the laser light after passing through the integrator can be suitable for application in projector equipment, such as rear projection structure or polarized 3D glasses. Because the laser light source depolarizer destroys the light collimation and light polarization of the laser light, the uniformity of the display image can be improved, color blocks can be reduced, and the quality of the projected image can be improved.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined in the attached patent application.

100,100a,100b,100c: laser light source depolarizer 110: laser light source 120: beam angle adjustment element 130: birefringent crystal 140: integrator 150,160: optical glue layer 132,134,132a,134a,132b,134b: surface 136,138: birefringent material 200: projection system 300: thin screen 302: viewing surface 304: projection surface 400: viewer L1,L2,L3,L4: laser light D1: first direction θ: diffusion angle

FIG. 1 is a schematic diagram of a laser light source depolarizer according to an embodiment of the present disclosure. FIG. 2 is a schematic diagram of the laser light source depolarizer of FIG. 1 applied to a projector device. FIG. 3 is a schematic diagram of a laser light source depolarizer according to another embodiment of the present disclosure. FIG. 4 is a schematic diagram of a laser light source depolarizer according to another embodiment of the present disclosure. FIG. 5 is a schematic diagram of a laser light source coaxial device according to another embodiment of the present disclosure.

100: Laser light source depolarizer

110:Laser light source

120: Beam angle adjustment element

130: Birefringent crystal

140: Integrator

132,134:Surface

L1, L2, L3, L4: Laser light

D1: First direction

θ: Diffusion angle

Claims (10)

A laser light source depolarizer comprises: a laser light source configured to emit a first laser light; a beam angle adjustment element configured to change a diffusion angle of the first laser light to generate a second laser light; a birefringent crystal, wherein the beam angle adjustment element is located between the laser light source and the birefringent crystal, wherein the second laser light with different traveling directions passes through the birefringent crystal, and the birefringent crystal is configured to destroy the polarity of the second laser light; and an integrator, wherein the birefringent crystal is located between the beam angle adjustment element and the integrator. The laser light source depolarizer as described in claim 1, wherein the surface of the birefringent crystal facing the beam angle adjustment element and the surface of the birefringent crystal facing the integrator are parallel to each other. A laser light source depolarizer as described in claim 1, wherein the birefringent crystal is formed in one piece. A laser light source depolarizer as described in claim 1, wherein the beam angle adjustment element is a diffuser or a lens. The laser light source depolarizer as described in claim 1 further comprises an optical glue layer located between the beam angle adjustment element and the birefringent crystal. A laser light source depolarizer as described in claim 5, wherein the optical glue layer contacts the birefringent crystal. The laser light source depolarizer as described in claim 1 further comprises an optical glue layer located between the birefringent crystal and the integrator. A laser light source depolarizer as described in claim 1, wherein the birefringent crystal has an anti-reflection film. The laser light source depolarizer as described in claim 1, wherein the surface of the birefringent crystal facing the beam angle adjustment element and the surface of the birefringent crystal facing the integrator have an angle. A projector device, comprising: a laser light source depolarizer as described in claim 1; a screen having a projection surface and a viewing surface located on opposite sides; and a projection module, receiving light from the integrator and converting the light into an image to be projected onto the screen; wherein the projection module is located on the projection surface of the screen.

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