CN105388603A - TIR Prism System for DLP Projector - Google Patents

Abstract

The invention discloses a TIR prism system for a DLP projector, which comprises a first TIR prism and a second TIR prism, wherein the first TIR prism is arranged close to a DMD chip, the second TIR prism is attached to the first TIR prism, the second TIR prism comprises a CD surface, a DE surface and a CE surface, the CE surface is attached to the first TIR prism, and the DE surface is an emergent surface. The invention greatly reduces the size of the prism, and does not influence the imaging of the projector because non-imaging light rays enter the projection lens.

Description

TIR Prism System for DLP Projector

technical field

The invention relates to the field of projectors, in particular to a TIR prism system for a DLP projector.

Background technique

The working principle of the optical system of the projector is shown in Figure 1. The white light generated by the light source bulb 1 is divided into three primary colors of red, green and blue light by the color wheel 2, and the light of the light source whose energy distribution form is normal distribution is homogenized by the light collecting rod 3 , and then through the relay optical system 4, mirror 5 and TIR prism system 6, the homogenized light is irradiated onto the display component DMD chip 7, and the imaging light is reflected into the projection lens 8 through the modulation of the DMD chip 7, and then through the projection The lens 8 is projected onto the screen, and the non-imaging light is modulated by the DMD and reflected out of the projection lens 8 .

The TIR prism system 6 includes two first TIR prisms 60 and a second TIR prism 61 that are attached to each other, wherein the second TIR prism 61 includes a CD face, a DE face and a CE face, wherein the CE face and the first TIR prism 60 Fitting, the DE surface is the outgoing surface, and the angle between the CD surface and the CE surface is α.

According to the principle of light reflection, if the non-imaging light is irradiated on the CD surface, it will be totally reflected. After the non-imaging light is totally reflected by the CD surface, part or all of the non-imaging light will enter the projection lens, as shown in Figure 2. In the optical design, the non-imaging light cannot enter the lens, otherwise it will become stray light, which will affect the imaging quality of the projection lens. Therefore, when designing the TIR prism, the α angle will be enlarged according to the area of the non-imaging light. At the same time, the DE surface Increase the height so that the non-imaging light does not irradiate the CD surface, so that the light will not enter the projection lens when it propagates out of the second TIR prism. However, if the non-imaging light is not irradiated on the CD surface by increasing the α angle, the height of the second TIR prism will become higher, as shown by the dotted line in Figure 2, which will result in the overall height of the projector Becomes high.

Contents of the invention

The present invention is aimed at the above problems, and researches and designs a TIR prism system for DLP projectors that has a simple structure, does not allow non-imaging rays to enter the projection lens and reduces the size of the TIR prism,

Technical means of the present invention is as follows:

A TIR prism system for a DLP projector, the prism system includes a first TIR prism arranged near a DMD chip and a second TIR prism bonded to the first TIR prism, the second TIR prism includes a CD surface, A DE surface and a CE surface, wherein the CE surface is attached to the first TIR prism, and the DE surface is an outgoing surface, wherein the prism system also includes a light-absorbing plate for absorbing non-imaging light reflected from the CD surface, The light absorbing plate is arranged between the DE surface and the projection lens, and between the CD surface and the projection lens.

Further, the CD plane is perpendicular to the DE plane.

Further, the light-absorbing plate is parallel to the DE plane.

Further, the distance between the light-absorbing plate and the DE surface is .

Further, the first TIR prism and the second TIR prism use BK7 glass.

Further, the reflection angle of the DMD chip is 17°.

Furthermore, the width d of the light absorbing plate is not less than the length s of the short side of the DMD chip.

Compared with the prior art, the TIR prism system for the DLP projector of the present invention has the following beneficial effects: the size of the prism is greatly reduced, and non-imaging light rays are not allowed to enter the projection lens to affect the imaging of the projector.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments described in this application. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic diagram of the principle of a projector in the prior art;

2 is a schematic diagram of light propagation after the second TIR prism in the prior art is shortened;

Fig. 3 is a schematic diagram of an embodiment of the present invention.

In the figure: 1. bulb, 2. color wheel, 3. light collecting rod, 4. relay optical system, 5. reflector, 6. TIR prism system, 60. first TIR prism, 62. second TIR prism, 7. DMD chip, 8. Projection lens, 9. Light-absorbing plate.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The directional terms mentioned in the present invention, such as "upper", "lower", "front", "rear", "left", "right", etc., are only referring to the directions of the attached drawings. Accordingly, the directional terms are used to illustrate, not to limit, the invention.

The DLP projector as shown in Figure 3 uses TIR prism system, comprises the first TIR prism 60 that is arranged near DMD chip 7 and the second TIR prism 61 that is bonded with the first TIR prism 60, and the second TIR prism 61 comprises CD surface , DE surface and CE surface, wherein the CE surface is bonded with the first TIR prism 60, the DE surface is the outgoing surface, and the prism system also includes a light-absorbing plate 9 for absorbing non-imaging light reflected from the CD surface, and the light-absorbing plate 9 is arranged on Between the DE plane and the projection lens 8 , and between the CD plane and the projection lens 8 .

To further miniaturize the prism system, the CD plane can be made perpendicular to the DE plane.

As a preferred embodiment of the present invention, the light-absorbing plate is parallel to the DE plane.

As another preferred embodiment of the present invention, the distance between the light absorbing plate 9 and the DE surface is 1 mm.

Specifically, the working principle of the embodiment of the present invention is as follows:

As shown in Figure 2, reduce the α angle to make the CD plane of the second TIR prism 61 perpendicular to the exit surface DE plane, the non-imaging light will be totally reflected on the CD plane, and after the non-imaging light leaves the second TIR prism 61, it will be All or most of the light enters the projection lens as stray light, resulting in serious attenuation of the projection picture quality. It can be seen that the non-imaging light (stray light) has a certain distance from the imaging light when it just propagates out of the second TIR prism 61 , so a light-absorbing plate 9 can be added when the non-imaging light through total reflection propagates out of the second TIR prism 61, as shown in FIG. It does not enter into the projection mirror 8 and does not affect the imaging quality of the projection lens 8, and the light-absorbing plate 9 does not have any influence on the imaging light.

The principles for placing the light-absorbing plate 9 are: 1) try to cover (absorb) all non-imaging light (stray light) generated by total reflection on the CD surface. 2) The imaging light cannot be blocked.

The first TIR prism 60 and the second TIR prism 61 can use BK7, SF8, SK7 and other glasses. As a preferred embodiment of the present invention, the first TIR prism 60 and the second TIR prism 61 use BK7 glass.

As another preferred embodiment of the present invention, the reflection angle of the DMD chip 7 is 17°.

As yet another preferred embodiment of the present invention, the width d of the light absorbing plate is not less than the length s of the short side of the DMD chip 7 .

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (7)

1. a DLP projector TIR prism system, described prism system comprises the TIR prism arranged near dmd chip and the 2nd TIR prism of fitting with a described TIR prism, described 2nd TIR prism comprises CD face, DE face and CE face, wherein CE face and a described TIR prism are fitted, DE face is exit facet, it is characterized in that, described prism system also comprises the extinction plate for absorbing the non-imaged light from the reflection of CD face, described extinction plate is arranged between DE face and projection lens, and between CD face and projection lens.

2. TIR prism system according to claim 1, is characterized in that, described CD face is vertical with DE face.

3. TIR prism system according to claim 1, is characterized in that, described extinction plate is parallel with DE face.

4. TIR prism system according to claim 3, is characterized in that, the distance in described extinction plate and DE face is 1mm.

5. TIR prism system according to claim 1, is characterized in that, a described TIR prism and the 2nd TIR prism adopt BK7 glass.

6. TIR prism system according to claim 1, is characterized in that, the reflection angle of described dmd chip is 17 °.

7. the TIR prism system according to any one of claim 1-6, is characterized in that, the width d of described extinction plate is not less than the length s of dmd chip minor face.