CN110764354A

CN110764354A - Optical structure of LCD projector, projector and P light and S light conversion method

Info

Publication number: CN110764354A
Application number: CN201911055061.7A
Authority: CN
Inventors: 徐逸
Original assignee: Hing Spectrum Technology Chengdu Co Ltd
Current assignee: Hing Spectrum Technology Chengdu Co Ltd
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2020-02-07

Abstract

The invention discloses an optical structure of an LCD projector, the projector and a P light and S light conversion method, wherein the structure comprises an LED array, a primary lens array and a lamp cup type collimation and light equalization lens array which are in one-to-one correspondence with the LED array, an 1/4 wave plate, a reflective polarizer, a liquid crystal screen, a Fresnel lens, a reflector and a lens, and the components are arranged in sequence. The invention solves the problems of low uniformity, low lighting effect and disordered light of the traditional single LCD projector in illumination.

Description

Optical structure of LCD projector, projector and P light and S light conversion method

Technical Field

The invention belongs to the technical field of projector application, and particularly relates to an optical structure of an LCD projector.

Background

The existing single LCD projector uses an integrated LED light source, and after a single condenser lens or a reflecting funnel is used for simply condensing light, the light irradiates a Fresnel lens and then illuminates a liquid crystal screen. The liquid crystal screen displays images, the images are gathered through the Fresnel lens, and the images are projected on the screen through the lens after being reflected by the reflecting mirror.

The existing single LCD projector has simple structure of the illuminating part and low light collimation degree. The LED projection lamp has no conversion function of P light and S light, so that the lighting effect is low, and the single LCD projector has the characteristics of low brightness and poor uniformity.

In recent years, 1/4 wave plates and reflective polarizers are added between a fresnel lens and a liquid crystal screen, although the reflective polarizers can transmit P light and reflect S light, the reflected S light can also be subjected to polarization conversion after passing through 1/4 wave plates, but the part of light returns to an LED as original light and cannot be reflected back again. Can only reflect for many times in the form of diffuse reflection, form stray light and finally be lost. This method is therefore very inefficient.

Meanwhile, the lens can only adopt small light waves in order to shield stray light, so that the brightness of the projector is further reduced.

Therefore, the existing single LCD projector has the defect of low brightness, which seriously affects the application of the single LCD projector.

Disclosure of Invention

In order to overcome the defects, the inventor of the invention continuously reforms and innovates through long-term exploration and trial and multiple experiments and endeavors, provides an optical structure of an LCD projector, and solves the problems of low uniformity, low light efficiency and disordered light in the illumination of the conventional single LCD projector.

In order to achieve the purpose, the invention adopts the technical scheme that: an optical structure of an LCD projector comprises an LED array, a primary lens and a secondary lens array corresponding to the LED array, wherein 1/4 wave plates, a reflective polarizer, a liquid crystal screen, a Fresnel lens, a reflector and a lens are sequentially arranged behind the secondary lens.

According to the optical structure of the LCD projector provided by the invention, the reflective polarizer is not parallel to the liquid crystal screen and the 1/4 wave plate.

According to the optical structure of the LCD projector provided by the present invention, a further preferable technical solution is that the polarized light reflected by the reflective polarizer passes through 1/4 wave plate, then is reflected by the secondary lens, and then passes through 1/4 wave plate again, so as to complete the conversion between the P light and the S light.

According to the optical structure of the LCD projector provided by the present invention, it is further preferable that the reflection of the light by the secondary lens array is based on the total reflection principle of the angle greater than brewss angle rather than the reflection medium principle.

According to the optical structure of the LCD projector provided by the present invention, it is further preferable that the LED chip in the LED array is one or more.

According to the optical structure of the LCD projector provided by the present invention, a preferable technical solution is that the primary lens is a convex lens, and the secondary lens is a cup-shaped collimating and light-equalizing lens.

According to the optical structure of the LCD projector provided by the present invention, it is further preferable that the primary lens and the secondary lens collimate the LED light, and the smaller the angle of the collimated light, the better.

According to the optical structure of the LCD projector provided by the invention, the further preferable technical scheme is that the illumination intensity of the collimated light through the single secondary lens is high in the middle, and the edge part is gradually weakened without obvious boundaries.

According to the optical structure of the LCD projector provided by the invention, a further preferable technical scheme is that 1/4 wave plates and reflective polarizers are sequentially arranged between the secondary lens array and the liquid crystal screen.

According to the optical structure of the LCD projector provided by the present invention, a preferable technical solution is that after being collimated and equalized by the secondary lens, a collimated light with an incident angle smaller than 7.5 degrees is formed.

The invention also provides an LCD projector on the basis of the optical structure, and a projection lens of the projector comprises the optical structure.

The invention also provides a method for converting P light and S light of an LCD projector on the basis of the optical structure, which comprises the following steps: the light emitted by the LED array is collimated and equalized by the primary lens and the secondary lens, passes through the 1/4 wave plate and then irradiates the reflective polarizer, wherein the P light penetrates through the liquid crystal screen and is reflected by the S light, the reflected S light enters the secondary lens after passing through the 1/4 wave plate, and passes through the 1/4 wave plate again after being reflected by the secondary lens and irradiates the reflective polarizer again, and the light passes through the 1/4 wave plate twice and is converted into the P light, so that the light can penetrate through the reflective polarizer and irradiate the liquid crystal screen, and similarly, the S light on the reflective polarizer can be transmitted through the S light and reflected by the P light, and the conversion between the P light and the S light can be also finished, so that the mutual conversion between the S light and the P light is realized.

Compared with the prior art, the technical scheme of the invention has the following advantages:

the invention solves the problems of low uniformity, low lighting effect and disordered light of the traditional single LCD projector in illumination: after the light emitted by the LED light source is collimated and equalized by the lamp cup type collimation and equalization lens, collimated light with an incident angle smaller than 7.5 degrees can be formed, see figure 2, the intensity difference of the collimated light is smaller than 10%, and figures 5 and 6. Thereby solving the disadvantages of the illumination part of the traditional single LCD projector.

The traditional single LCD has no P light and S light conversion function, which causes 50% of polarized light waste, in the invention, the light emitted by the LED light source is collimated and equalized by the primary lens and the lamp cup type collimation and equalization lens, and then irradiates onto the reflection type polarizer after passing through the 1/4 wave plate, wherein the P light penetrates and irradiates onto the liquid crystal screen, the S light reflects, the reflected S light enters the lamp cup type collimation and equalization lens after passing through the 1/4 wave plate, passes through the 1/4 wave plate again after reflecting by the lens, and irradiates onto the reflection type polarizer again, because the light passes through the 1/4 wave plate twice, the S light is converted into the P light, so that the P light can be transmitted through the reflection type polarizer and irradiates onto the liquid crystal screen. Similarly, the conversion between the P light and the S light can be completed by the S light transmission and the P light reflection on the reflective polarizer, which is shown in fig. 7, thereby greatly improving the light efficiency of the single LCD projector.

In the invention, because the illumination part is collimated light and has less stray light, larger light can be used in the design of the lens without reducing the contrast of the image, thereby further improving the brightness of the projector.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram of the present invention.

Fig. 2 is a light intensity distribution diagram.

Fig. 3 is a graph of the amount of incident light, and fig. 4 is a graph of fig. 3.

Fig. 5 is a graph of the amount of incident light, and fig. 6 is a line graph of fig. 5.

Fig. 7 is a reflection optical path diagram.

The reference numbers in the figures are: 1-LED array 2-primary lens 3-secondary lens 4-1/4 wave plate 5-reflective polarizer 6-liquid crystal screen 7-fresnel lens 8-reflector 9-lens.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, not all of the embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention.

Examples

As shown in fig. 1: the technical problem to be solved by the invention is to provide a novel LCD projector optical structure, which comprises an LED array 1, a primary lens 2 array and a secondary lens 3 array which are in one-to-one correspondence with the LED array, an 1/4 wave plate 4, a reflective polarizer 5, a liquid crystal screen 6, a Fresnel lens 7, a reflector 8 and a lens 9, wherein the LED array 1, the primary lens 2 array and the secondary lens 3 array are sequentially arranged. The primary lens adopts a convex lens, and the secondary lens adopts a lamp cup type collimation and light-equalizing lens. The included angle between the Fresnel lens 7 and the reflector 8 is 45 degrees. The array of secondary lenses 3, the 1/4 wave plate 4, the liquid crystal screen 6 and the Fresnel lens 7 are parallel, and the lens 9 and the liquid crystal screen 6 are vertical.

The reflective polarizer 5 in this embodiment is not parallel to the liquid crystal panel 6 and the 1/4 wave plate 4, but has a small included angle, as shown in fig. 1.

The part of the polarized light reflected by the reflective polarizer 5 in this embodiment passes through the 1/4 wave plate 4, and then passes through the 1/4 wave plate 4 again after being reflected by the secondary lens 3, i.e., the lamp cup type collimating lens, so as to complete the conversion between the P light and the S light.

The reflection of the secondary lens 3, i.e. the lamp cup type collimation and light equalization lens array, on light rays in the embodiment is based on the total reflection principle of more than a Brewss angle rather than the reflection medium principle. And the secondary lens 3 array, the primary lens 2 array and the LED array 1 light source are in one-to-one correspondence.

The LED chip in the LED array 1 light source referred to in this embodiment may be one LED chip or a plurality of LED chips according to actual use. And the LED light is collimated by the primary lens 2 and the secondary lens 3 in the present embodiment, the smaller the angle of the collimated light is, the better.

As shown in fig. 3-6, the illumination intensity of the collimated light by the single lamp cup type collimating and light equalizing lens is high in the middle, the edge part is gradually weakened, no obvious boundary exists, after the two collimated light edges are overlapped, the light intensity of the overlapped area is basically consistent in the middle area, and no obvious bright and dark area exists.

In this embodiment, 1/4 wave plate 4 and reflective polarizer 5 are sequentially arranged between the array of secondary lenses 3 and the liquid crystal panel 6, and no fresnel lens is arranged between the array of secondary lenses 3 and the liquid crystal panel 6 according to practical situations.

The liquid crystal screen 6 in the embodiment has good backlight collimation and less stray light, and a large and smooth lens 9 can be used to further improve the brightness of the projector.

In this embodiment, light emitted from the LED light source 1 is collimated by the primary lens 2 and the lamp cup type collimating and light equalizing lens 3 to form collimated light with an incident angle smaller than 7.5 degrees, and as shown in fig. 2, the light intensity is distributed to be high in the middle and gradually changed to be low at the edge.

Referring to fig. 4 and 5, the light intensity is uniform after the array is formed, and as shown in fig. 5 and 6, the light rays collimated and uniform by the lens array pass through 1/4 wave plate 4 and then irradiate onto the reflective polarizer 5, wherein the P light passes through and irradiates onto the liquid crystal screen 6, and the S light is reflected, because the reflective polarizer 5 is not parallel to 1/4 wave plate 4 and the liquid crystal screen 6, the reflected S light does not return as it is, but passes through 1/4 wave plate 4 and then enters into the lamp cup type collimating and light equalizing lens 3 at another angle, the lamp cup type collimating and light equalizing lens 3 is designed reasonably, so that the light rays can be reflected for multiple times in the lamp cup type collimating and light equalizing lens 3 and then irradiate onto 1/4 wave plate again, the light rays pass through 1/4 wave plate 4 again and then irradiate onto the reflective polarizer 5, because the light rays pass through 1/4 twice, the S light is already converted into the, so that it can be irradiated onto the liquid crystal panel 6 through the reflective polarizer 5, see fig. 7. Similarly, the conversion between the P light and the S light can be accomplished by the S light transmission and the P light reflection on the reflective polarizer. The polarized light irradiated on the liquid crystal screen 6 is converged by the Fresnel lens 7, reflected by the reflective mirror 8, and projected to the curtain through the lens 9 to form an image.

The invention solves the problems of low uniformity, low lighting effect and disordered light of the traditional single LCD projector in illumination: the light emitted by the LED light source is collimated and equalized by the lamp cup type collimation and equalization lens to form collimated light with an incident angle smaller than 7.5 degrees, and the intensity difference of the collimated light is smaller than 10 percent, so that the defect of the illumination part of the traditional single LCD projector is overcome.

The traditional single LCD has no P light and S light conversion function, which causes 50% of polarized light waste, in the invention, the light emitted by the LED light source is collimated and equalized by the primary lens and the lamp cup type collimation and equalization lens, and then irradiates onto the reflection type polarizer after passing through the 1/4 wave plate, wherein the P light penetrates and irradiates onto the liquid crystal screen, the S light reflects, the reflected S light enters the lamp cup type collimation and equalization lens after passing through the 1/4 wave plate, passes through the 1/4 wave plate again after reflecting by the lens, and irradiates onto the reflection type polarizer again, because the light passes through the 1/4 wave plate twice, the S light is converted into the P light, so that the P light can be transmitted through the reflection type polarizer and irradiates onto the liquid crystal screen. Similarly, the conversion between the P light and the S light can be accomplished by the S light transmission and the P light reflection on the reflective polarizer. The light efficiency of the single LCD projector is greatly improved.

For the above devices or parts, those skilled in the art can replace or adjust the angle according to the corresponding use condition, so that the product effect is more suitable for different projectors.

The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and these modifications and adaptations should be considered within the scope of the invention.

Claims

1. An optical structure of an LCD projector is characterized by comprising an LED array, a primary lens and a secondary lens array corresponding to the LED array, wherein 1/4 wave plates, a reflective polarizer, a liquid crystal screen, a Fresnel lens, a reflector and a lens are sequentially arranged behind the secondary lens.

2. An optical structure of an LCD projector as claimed in claim 1, wherein the reflective polarizer is not parallel to the liquid crystal panel and the 1/4 wave plate.

3. The optical structure of an LCD projector as claimed in claim 1, wherein the polarized light reflected by the reflective polarizer passes through 1/4 wave plate, is reflected by the secondary lens, and passes through 1/4 wave plate again to complete the conversion between P light and S light.

4. An optical structure of an LCD projector as claimed in claim 1, wherein the reflection of the light by the secondary lens array is based on the principle of total reflection greater than the brewss angle rather than the principle of a reflective medium.

5. An optical structure as claimed in claim 1, wherein the LED chips in the LED array are one or more.

6. An optical structure as claimed in claim 1, wherein the primary lens is a convex lens and the secondary lens is a lamp cup type collimating and light-equalizing lens.

7. An optical structure of an LCD projector as claimed in claim 1, wherein the LED light is collimated by the primary and secondary lenses, and the angle of the collimated light is as small as possible.

8. An optical structure for an LCD projector as claimed in claim 1, wherein the illumination intensity of the collimated light by the single secondary lens is high in the middle, and the edge portion is gradually weakened without a distinct boundary.

9. An optical structure of an LCD projector as claimed in claim 1, wherein 1/4 wave plate and a reflective polarizer are sequentially disposed between the secondary lens array and the liquid crystal panel.

10. An optical structure as claimed in claim 1, wherein the collimated light with an incident angle of less than 7.5 degrees is formed after being collimated and homogenized by the secondary lens.

11. An LCD projector, wherein the projection lens of the projector comprises the optical structure of any one of claims 1-10.

12. A P light and S light conversion method of LCD projector is characterized in that the conversion process is as follows: the light emitted by the LED array is collimated and equalized by the primary lens and the secondary lens, passes through the 1/4 wave plate and then irradiates the reflective polarizer, wherein the P light penetrates through the liquid crystal screen and is reflected by the S light, the reflected S light enters the secondary lens after passing through the 1/4 wave plate, and passes through the 1/4 wave plate again after being reflected by the secondary lens and irradiates the reflective polarizer again, and the light passes through the 1/4 wave plate twice and is converted into the P light, so that the light can penetrate through the reflective polarizer and irradiate the liquid crystal screen, and similarly, the S light on the reflective polarizer can be transmitted through the S light and reflected by the P light, and the conversion between the P light and the S light can be also finished, so that the mutual conversion between the S light and the P light is realized.