CN1652018A - Oblique gradient spectroscopic film, its detection method, and liquid crystal projection display device - Google Patents

Abstract

An oblique gradual change type light splitting film, a detection method thereof and a liquid crystal projection display device are provided, wherein the oblique gradual change type light splitting film comprises a light splitting film, and the film layer property of the light splitting film has a gradual change direction. The gradual change direction of the light splitting film is related to an incident angle of incident light. Therefore, by adjusting the gradient direction of the thickness of the film layer or the property of the film layer coated on the beam splitter and the distribution of the thickness of the film layer or the property of the film layer in the gradient direction, a beam splitter with a relatively uniform distribution, such as the energy, the color, the reflectivity or the transmissivity, and the beam splitter with the light beam of different colors can be obtained. Therefore, the brightness, uniformity and contrast definition of the output image of the reflective liquid crystal projection display device can be improved to a considerable extent.

Description

Oblique gradient spectroscopic film, its detection method, and liquid crystal projection display device

technical field

The invention relates to a gradient light splitting film and a reflective liquid crystal projection display device. And in particular, it relates to an oblique gradient light-splitting film, inspection method, and reflective liquid crystal projection display device that can be applied to off-axis projection light-mechanical systems and improve its uniformity, brightness, and contrast clarity.

Background technique

In recent years, liquid crystal displays (Liquid Crystal Display, LCD) have gradually replaced traditional cathode ray tubes (Cathode Ray Tube, CRT) due to their advantages of thin, light weight, low operating voltage, power saving, and no radiation. ), and become the mainstream of display devices. However, due to limitations in liquid crystal display (LCD) technology, most of them can only be limited to products with a display screen of 30 or less. As for the displays from 30:00 to 60:00, the development of PDP (Plasma Display Panel, PDP) was originally the most promising. However, because its cost is too high, it cannot become a product acceptable to ordinary consumers.

Therefore, for the development direction of the large-size display device, the display device adopting the projection technology is currently being developed, such as a reflective projection display device (reflective projection display device) and a rear projection display device (rear projection display device). Among them, reflective projection display devices include liquid crystal projectors (Liquid Crystal Projector, LCP), digital light source projectors (Digital Light Projector, DLP) and reflective liquid crystal (Liquid Crystal On Silicon, LCOS) projection display devices, etc. Reflective liquid crystal (LCOS) projection technology is also used in rear projection display devices. Although the products currently on the market are mainly liquid crystal projectors (LCP) and digital light source deployment projectors (DLP), because reflective liquid crystal (LCOS) projection technology has low cost, high aperture ratio (up to 90%), high Resolution (pixel pitch can reach 12μm or less), and many manufacturers have begun to develop this technology.

Therefore, reflective liquid crystal (LCOS) projection technology can be said to be the key technology of reflective projection display devices and rear projection display devices. Its biggest advantage is that it can greatly reduce panel production costs and has high resolution.

FIG. 1 is a schematic diagram showing a known reflective liquid crystal (LCOS) projection device. Referring to FIG. 1 , the reflective liquid crystal (LCOS) projection device and its working principle are basically white light 104 emitted by a light source 102 , and red light 112 , green light 122 and blue light 142 are separated through a filter 106 and a dichroic lens 108 . Wherein, through a dichroic mirror 110 , the red light 112 is reflected by a mirror 114 and reaches a polarization beam splitter (Polarization Beam Splitter, PBS) 116 .

2A and 2B are schematic diagrams showing the working principle of a known polarizing beam splitter (PBS). Here, the incident light is red light as an example. When the red light 112 passes through the polarizing beam splitter (PBS) 116 in front of the reflective liquid crystal panel (LCOSpanel) 118, the polarizing beam splitter (PBS) 116 will only convert the light in one of the polarization directions The polarized light is reflected into the LCOS panel, such as the polarizing beam splitter (PBS) 116 , which means that the S-polarized light (S-polarization light) of the red light 112 enters the reflective liquid crystal panel 118 . Referring to FIG. 2A, when the image to be displayed on the reflective liquid crystal panel 118 is in a dark state (dark), the S polarized light incident on the reflective liquid crystal panel 118 will be reflected back, and cannot enter the light-combining prism (X-Cube )152. Next, referring to FIG. 2B, when the image to be displayed on the reflective liquid crystal panel 118 is in a bright state, the S polarized light incident on the LCOS panel 118 will be changed into P polarized light (P-polarization light) 120 by the LCOS panel, Therefore, it can pass through the polarization beam splitter 116 and reach the light combining prism 152 .

Therefore, the red light 112, the green light 122 and the blue light 142 are respectively reflected on the reflective liquid crystal panels 118, 132 and 146 through their polarization beam splitters (PBS) 116, 130 and 144, and the reflective liquid crystal panels will have images After part of the red light, green light and blue light are partially polarized, the partially polarized red light 120 , green light 134 and blue light 148 are combined through the light-combining prism 152 to obtain an image signal, and finally pass through the zoom lens 154 to convert the The image signal is projected onto the monitor.

From the above, it can be seen that in the existing known reflective liquid crystal projection design, the light splitting and light combining components are important components, because if the ratio of the three primary colors of light splitting or light combining is not uniform, it will cause unevenness of the combined image. There is color deviation, which directly affects the uniformity and brightness of the image. In addition, if the focus of the combined three primary colors of light is not correct, the combined image will be blurred, which will directly affect the resolution of the image.

At present, in the known reflective liquid crystal projection design, most of the light splitting components use a dichroic prism (X-cube) or a dichroic mirror (dichroic mirror) or a dichroic filter (dichroic filter). For example, the light-combining prism (X-cube) 110 shown in FIG. 1 can be used as a beam-splitting prism when the direction of light traveling is opposite. A dichroic mirror or a dichroic filter is used in the dichroic mirror (dichroic mirror) 110 shown in FIG. 1 . Secondly, in the currently known reflective liquid crystal projection design, the light path (light path) of its light travel is mostly parallel to the normal direction (normal) of the reflective surface of the light splitting component. This kind of design is generally called coaxial (on -axis) design. For example, in FIG. 1 , the traveling direction of the red light 112 is perpendicular to the reflective surface 162 of the polarization beam splitter 116 and the reflective surface 164 of the light combining prism 152 .

FIG. 3A is a top view showing a conventional coaxial optical design of a beam splitter. FIG. 3B is a cross-sectional view showing a schematic view taken from direction A in FIG. 3A . FIG. 3C is a cross-sectional view showing a schematic diagram of a light spot (light spot) obtained on the B-B cross-section in FIG. 3A. From FIG. 3B , it can be known that the light ray 302 is vertically incident on the reflective surface 306 of the beam splitter 304 . From FIG. 3C , it can be seen that the shape of the light spot (light spot) 312 obtained by the light 302 on the reflective surface 306 is an ellipse. Generally speaking, such a coaxial optical design can obtain a light spot 312 with good color uniformity.

When better color uniformity is required, optical coating technology can be used to coat dichroic mirrors or dichroic filters with dielectric or metal films of different properties to change the characteristics of light wave transmission by means of light interference. For example, a special optical film coating can be coated on the dichroic mirror or dichroic filter to form a horizontal gradient coating dichroic mirror or a horizontal gradient coating dichroic filter. , to filter out the required uniform and high-transmittance three-primary-color light from the incident light, so as to facilitate the final synthesis of an image with better color uniformity, so as to improve the color uniformity in the coaxial optical design.

FIG. 4 is a schematic diagram showing an off-axis reflective liquid crystal (LCOS) projection device. Referring to FIG. 4 , the off-axis reflective liquid crystal (LCOS) projection device basically works by emitting white light from a light source 402 through a dichroic mirror 404 to separate red light 406, green light 408 and blue light 410. . After the three primary colors are polarized by a polarizer 412, they are incident on a reflective liquid crystal panel 414, and the red light, green light, and blue light having an image portion are partially polarized by the reflective liquid crystal panel 414, and then pass through an analyzer ( The analyzer 416 and the dichroic mirror 418 combine the partially polarized red light, green light and blue light to obtain an image signal, and finally project the image signal onto the display screen.

In the off-axis reflective liquid crystal projection device, there is a problem that the color distribution of the three primary colors of light is not uniform after light splitting. Generally speaking, even in an off-axis reflective liquid crystal projection device using a horizontal gradient dichroic mirror or a horizontal gradient dichroic filter, the distribution of the colors of the three primary colors after light separation is still not uniform enough. Therefore, how to improve the uniformity and contrast definition of each color distribution of the three primary colors after splitting in the off-axis reflective liquid crystal projection device is a very important issue.

Contents of the invention

An object of the present invention is to provide an oblique gradient light-splitting film to effectively improve the uniformity, brightness and contrast definition of the light beams obtained through the oblique gradient light-splitting film.

Another object of the present invention is to provide a reflective liquid crystal projection display device, which has the gradient gradient light-splitting film of the present invention, so as to effectively improve the uniformity, brightness and contrast sharpness.

Another object of the present invention is to provide a method for detecting oblique gradient spectroscopic film to effectively detect the uniformity, brightness and contrast definition of the spectroscopic beam obtained through the oblique gradient spectroscopic film.

In order to achieve an object of the present invention, the present invention proposes a kind of oblique gradient type light-splitting film, which can be applied to an off-axis reflective liquid crystal projection display device, which includes a light-splitting film, wherein the property of a layer of the light-splitting film is Has a gradient direction. Wherein the gradient direction of the light-splitting film is related to an incident angle of an incident light, so that a light characteristic of the incident light on a light spot on the light-splitting film can be uniformly distributed.

In an embodiment of the present invention, the material of the above-mentioned oblique gradient light-splitting film may include dielectric or metal.

In an embodiment of the present invention, in the above-mentioned obliquely graded spectroscopic film, the graded film properties may include film thickness or dielectric properties.

In an embodiment of the present invention, in the above-mentioned obliquely gradient light-splitting film, the characteristics of the obtained light spot may include uniform energy distribution, uniform reflectance distribution, or the spectral ratio of different colors of light is for uniform.

In order to achieve another object of the present invention, the present invention proposes a reflective liquid crystal projection device, which includes a light source, a color separation mirror, a polarizer, a reflective liquid crystal panel, a detector A polarizer (analyzer) and a light combining mirror (color recombination mirror). Wherein, the light source is used to emit white light, which is separated into three primary colors through a color separation mirror. After the three primary colors are polarized by the polarizer, they are incident on the reflective liquid crystal panel, and the three primary colors with the image part are partially polarized by the reflective liquid crystal panel, and then pass through the analyzer and the light combining mirror (color) Recombination mirror) combines the partially polarized three primary colors of light to obtain an image signal, and finally projects the image signal onto the display. Wherein at least one of the dichroic mirror or the light combining mirror is formed with the gradient gradient light-splitting film of the present invention. The detailed description of the gradient gradient light-splitting film can be found in the above description and will not be repeated here.

In order to achieve yet another objective of the present invention, the present invention proposes a detection method for oblique gradient light-splitting films. The method includes providing an incident light, which has a plurality of different incident angles for an oblique gradient light splitting film; and detecting a light characteristic of a split light beam obtained by detecting the incident light at different incident angles Is it evenly distributed.

In an embodiment of the present invention, in the detection method of the oblique graded spectroscopic film as described above, the light characteristics of the spectroscopic beam include energy distribution, reflectivity, or spectrophotometry of different colors of light.

To sum up, with the help of the oblique gradient spectroscopic film and its detection method provided by the present invention, as well as its reflective liquid crystal projection display device, because the gradient direction of the thickness or property of the film layer coated on the spectroscopic mirror is different from that of the incident light related to the angle of incidence. Therefore, by adjusting the direction of the thickness of the film coated on the beam splitter or the properties of the film, and the distribution of the thickness of the film or the properties of the film in the direction of the change, for example, energy, color, reflectivity or penetration can be obtained. Efficiency, and the spectrophotometry of different colors of light, etc., are fairly uniformly distributed split beams. Therefore, the uniformity of the split beams, the uniformity between the split beams of different colors, and the available energy of the split beams of the reflective liquid crystal projection display device can be improved to a considerable extent, that is, the brightness, uniformity and contrast clarity of the output image can be improved.

In order to make the above and other objects, features, and advantages of the present invention more clearly understood, a preferred embodiment is specifically cited below, and in conjunction with the accompanying drawings, the detailed description is as follows:

Description of drawings

Fig. 1 is a schematic diagram showing a known reflective liquid crystal (LCOS) projection device;

2A and FIG. 2B are schematic diagrams showing the working principle of a known polarizing beam splitter (PBS);

Fig. 3 A is a top view, represents the coaxial optical design of known spectroscope;

Fig. 3B is a cross-sectional view, showing a schematic diagram obtained from direction A in Fig. 3A;

Fig. 3 C is a sectional view, represents among Fig. 3 A, the light spot (light spot) schematic diagram obtained on B-B section;

4 is a schematic diagram showing an off-axis (off-axis) reflective liquid crystal (LCOS) projection device;

Figure 5A is a top view showing the off-axis optical design of the beam splitter;

Fig. 5B is a cross-sectional view, showing a schematic diagram obtained from direction C in Fig. 5A;

Figure 5C is a cross-sectional view showing a schematic diagram of a light spot (light spot) obtained on the D-D section in Figure 5A;

6 is a cross-sectional view showing a horizontal gradient beamsplitter for a schematic diagram of an off-axis optical design; and

7 is a cross-sectional view showing an oblique gradient beam splitter for a schematic diagram of an off-axis optical design.

Explanation of reference signs:

102: light source

104: white light

106: Optical filter

108: dichroic lens

110: dichroic mirror

114, 124, 126, 128: mirrors

112: red light

116, 130, 144: polarizing beam splitter

118, 132, 146, 200: Reflective LCD panel

120: Polarized red light

122: green light

134: Polarized green light

142: Blu-ray

148: polarized blue light

152: Combined light prism

154: zoom lens

162, 164: reflective surface

302: light

304: beam splitter

306: reflective surface

312: Spot

402: light source

404: dichroic mirror

406: red light

408: green light

410: Blu-ray

412: Polarizer

414: reflective LCD panel

416: Analyzer

418: Combined light prism

502: light

504: beam splitter

506: reflective surface

512: Spot

602, 702: reflective surface

604, 704: straight line

E, F: Arrows

Detailed ways

FIG. 5A is a top view showing the off-axis optical design of the beam splitter. FIG. 5B is a cross-sectional view showing a schematic view taken from direction C in FIG. 5A . FIG. 5C is a cross-sectional view showing a schematic diagram of a light spot (light spot) obtained on the D-D cross-section in FIG. 5A. From FIG. 5B , it can be known that the light ray 502 is not perpendicularly incident on the reflective surface 506 of the beam splitter 504 , but has an angle with the normal of the reflective surface 506 . From Fig. 5C, it can be known that the shape of the light spot (light spot) 512 obtained by the light ray 502 on the reflective surface 506 is an oblique ellipse, and in this off-axis optical design, the color uniformity of the light spot 512 not good.

When it is necessary to obtain better color uniformity, one of the improvement methods is to use optical coating technology to coat the beam splitter 504 with dielectric or metal films with different properties, so as to change the transmission of light waves with the help of light interference. characteristics. However, in this off-axis optical design, instead of forming a horizontal gradient beam splitter, a bevel gradient coating dichroic mirror is formed instead.

FIG. 6 is a cross-sectional view showing a horizontal gradient beam splitter for a schematic diagram of an off-axis optical design. Referring to FIG. 6 , the coating on the reflective surface 602 of the beam splitter is gradually changed, for example, in the direction of the arrow E, the thickness of the coating changes gradually. Basically, for a horizontal graded beamsplitter, the arrow E is in the horizontal direction. As for the incident direction of the light, for example, in FIG. 6 , the light with the same incident angle is represented by a straight line 604 . Therefore, it can be known that the incident direction of the light is not related to the change direction of the film thickness, that is, the arrow E. Therefore, in the off-axis optical design, the light is obliquely incident, so the color distribution on the obtained spot is uneven.

7 is a cross-sectional view showing an oblique gradient beam splitter for a schematic diagram of an off-axis optical design. With reference to Fig. 7, wherein on the reflective surface 702 of the beam splitter, the gradient direction of the coated film thickness, or the gradient direction of the film property, for example, in the direction of the arrow F, to cause the reflective surface of the beam splitter to be plated on A gradual change in film thickness or properties. For oblique gradient beamsplitters, the arrow F is not necessarily in the horizontal direction, but is related to the incident direction of light. For example, rays with the same incident angle are represented by a straight line 704 , so the direction of the arrow F is related to the direction of the straight line 704 . By adjusting the direction of the film thickness or properties coated on the reflective surface of the beam splitter, such as the direction of the arrow F, and the distribution of the film thickness or properties in the direction of the arrow F, for example, the film thickness distribution The change of the color can get a light spot with a fairly uniform color distribution.

In an embodiment of the present invention, the above-mentioned straight line 704 may include a curve formed by the same incident angle, and is not necessarily a straight line.

In an embodiment of the present invention, the material of the above-mentioned oblique gradient light-splitting film may include dielectric or metal.

In an embodiment of the present invention, in the above-mentioned obliquely graded spectroscopic film, the graded film properties may include film thickness or dielectric properties.

In an embodiment of the present invention, in the above-mentioned obliquely gradient light-splitting film, the characteristics of the obtained light spot may include uniform energy distribution, uniform reflectance distribution, or the spectral ratio of different colors of light is for uniform.

In the present invention, a reflective liquid crystal (LCOS) projection device is provided. Here, the reflective liquid crystal projection device of the present invention can take the off-axis reflective liquid crystal projection device shown in FIG. 4 as an example, but the off-axis reflective liquid crystal projection device shown in FIG. 4 is only used as an example. not intended to limit the

the scope of the invention.

Referring to FIG. 4 , an off-axis reflective liquid crystal (LCOS) projection device includes a light source 402 for emitting white light, which is separated into three primary colors 406 , 408 and 410 through a color separation mirror 404 . The three primary color lights are polarized by a polarizer (polarizer) 412, and are incident on a reflective liquid crystal panel 414. After the three primary color lights having an image part are partially polarized by the reflective liquid crystal panel 414, they are then combined with an analyzer 416 A light mirror (color recombination mirror) 418 combines the partially polarized light of the three primary colors to obtain an image signal, and finally projects the image signal onto the display screen. Wherein at least one of the dichroic mirror 404 or the light-combining mirror 418 is formed with the obliquely graded dichroic film of the present invention, the detailed description of the obliquely graded dichroic film can be found in the above description and FIG. 7 , in This will not be repeated.

In the present invention, a detection method IQC (incoming quality control) of an oblique gradient spectroscopic film is provided. The method includes providing an incident light, which has a plurality of different incident angles for an oblique gradient light splitting film; and detecting a ray of a split light beam obtained by detecting the incident light at different incident angles Whether the feature is uniformly distributed.

In an embodiment of the present invention, in the detection method of the oblique graded spectroscopic film as described above, the light characteristics of the spectroscopic beam include energy distribution, reflectivity, or spectrophotometry of different colors of light.

To sum up, with the help of the oblique gradient spectroscopic film and its detection method provided by the present invention, as well as its reflective liquid crystal projection display device, because the gradient direction of the thickness or properties of the film coated on the spectroscope and the direction of the incident light related to the angle of incidence. Therefore, by adjusting the direction of the thickness of the film coated on the beam splitter or the properties of the film, and the distribution of the thickness of the film or the properties of the film in the direction of the change, for example, energy, color, reflectivity or transmittance can be obtained. , and a fairly uniform distribution of split beams such as the spectrophotometry of different colors of light. Therefore, the uniformity of the split beams, the uniformity between the split beams of different colors, and the available energy of the split beams of the reflective liquid crystal projection display device can be improved to a considerable extent, that is, the brightness, uniformity and contrast clarity of the output image can be improved.

Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can certainly make some changes and modifications without departing from the spirit and scope of the present invention. Modification, so the scope of protection of the present invention should be defined by the scope of claims of the patent application.

Claims (22)

1. oblique gradual change type pellicle applicable to one from shaft type reflection type liquid crystal projection display equipment, comprising:

One pellicle, wherein a membranous layer property of this pellicle has a gradual change direction;

Wherein this gradual change direction of this pellicle is relevant with an incident angle of an incident light, can obtain the light characteristic of this incident light on the hot spot on this pellicle whereby for evenly distributing.

2. oblique gradual change type pellicle as claimed in claim 1, it is characterized in that: this membranous layer property comprises a thicknesses of layers.

3. oblique gradual change type pellicle as claimed in claim 1, it is characterized in that: this membranous layer property comprises a dielectric property.

4. oblique gradual change type pellicle as claimed in claim 1, it is characterized in that: this rete comprises a dielectric.

5. oblique gradual change type pellicle as claimed in claim 1, it is characterized in that: this rete comprises a metallic film.

6. oblique gradual change type pellicle as claimed in claim 1 is characterized in that: this light characteristic of this hot spot comprises an energy distribution.

7. oblique gradual change type pellicle as claimed in claim 1 is characterized in that: this light characteristic of this hot spot comprises a reflectivity.

8. oblique gradual change type pellicle as claimed in claim 1 is characterized in that: this light characteristic of this hot spot comprises one fen luminosity to different colours light.

9. oblique gradual change type pellicle as claimed in claim 1 is characterized in that: this oblique gradual change type pellicle all can provide the even distribution of this light characteristic for this incident light of this different incident angles.

10. reflection type liquid crystal projection display equipment comprises:

One in order to send the light source of a white light;

One in order to be divided into this white light in the dichronic mirror of primaries;

One in order to the polaroid with this primaries polarization;

One reflection type liquid crystal panel, this reflection type liquid crystal panel according to a received image signal, will have the primaries partial polarization of image section in order to this primaries behind the polarization;

One checking bias slice; And

One closes light microscopic, and wherein this checking bias slice closes light microscopic in order to the primaries behind this partial polarization is combined with this, and obtains an output image signal;

Wherein, maybe this closes light microscopic on one of them to this dichronic mirror at least, is formed with an oblique gradual change type pellicle, and this oblique gradual change type pellicle comprises:

One pellicle, wherein a membranous layer property of this pellicle has a gradual change direction;

Wherein this gradual change direction of this pellicle is relevant with an incident direction of a light, can obtain the light characteristic of this incident ray on the hot spot on this film whereby for evenly distributing.

11. reflection type liquid crystal projection display equipment as claimed in claim 10 is characterized in that: this membranous layer property comprises a thicknesses of layers.

12. reflection type liquid crystal projection display equipment as claimed in claim 10 is characterized in that: this membranous layer property comprises a dielectric property.

13. reflection type liquid crystal projection display equipment as claimed in claim 10 is characterized in that: this rete comprises a dielectric.

14. reflection type liquid crystal projection display equipment as claimed in claim 10 is characterized in that: this rete comprises a metallic film.

15. reflection type liquid crystal projection display equipment as claimed in claim 10 is characterized in that: this light characteristic of this hot spot comprises an energy distribution.

16. reflection type liquid crystal projection display equipment as claimed in claim 10 is characterized in that: this light characteristic of this hot spot comprises a reflectivity.

17. reflection type liquid crystal projection display equipment as claimed in claim 10 is characterized in that: this light characteristic of this hot spot comprises one fen luminosity to different colours light.

18. reflection type liquid crystal projection display equipment as claimed in claim 10 is characterized in that: this oblique gradual change type pellicle is for this incident light of this different incident angles, and the even distribution of this light characteristic of this primaries of equal usefulness all can be provided.

19. the detection method of an oblique gradual change type pellicle comprises:

One incident light is provided, and this incident light has a plurality of different incident angles for an oblique gradual change type pellicle; And

Detect this incident light on those different incident angles, whether a light characteristic of a resulting beam split light beam is even distribution.

20. the detection method of oblique gradual change type pellicle as claimed in claim 19 is characterized in that: this light characteristic of this beam split light beam comprises an energy distribution.

21. the detection method of oblique gradual change type pellicle as claimed in claim 19 is characterized in that: this light characteristic of this beam split light beam comprises a reflectivity.

22. the detection method of oblique gradual change type pellicle as claimed in claim 19 is characterized in that: this light characteristic of this beam split light beam comprises one fen luminosity to different colours light.

Images