CN109884843B

CN109884843B - Projector with a light source

Info

Publication number: CN109884843B
Application number: CN201810148522.4A
Authority: CN
Inventors: 胡雅文; 林祐震; 云麒锥
Original assignee: Young Optics Inc
Current assignee: Young Optics Inc
Priority date: 2017-12-06
Filing date: 2018-02-13
Publication date: 2021-12-24
Anticipated expiration: 2038-02-13
Also published as: CN109884843A; TW201925899A; TWI670558B

Abstract

A projector includes a light source, a light-equalizing element, a light valve and a light-transmissive optical element. The light source can output an illumination beam, and the light equalizing element, the light valve and the optical element are arranged on a transmission path of the illumination beam. The optical element is arranged between the light valve and the light equalizing element and is positioned on the transmission path of the illumination light beam, the surface of the optical element is provided with a filter film, and the filter film is completely covered by the illumination light beam.

Description

Projector with a light source

Technical Field

The present invention relates to a projector, and more particularly, to a projector having a preferred image uniformity.

Background

The image projected by the projector is affected by various factors such as material absorption or lens coating, which may cause the intensity distribution of the three RGB colors to be inconsistent, resulting in poor uniformity of the chromaticity of the image, for example, a certain color in the central area has a strong light intensity and the surrounding colors are relatively weak. Therefore, the requirement of color uniformity specification, for example, the difference value of white color coordinates of the whole image needs to be less than 0.005, cannot be met. When the spliced television wall images are spliced by a plurality of projectors, the problem of poor color uniformity of the images is more prominent at the joints, and the overall quality and visual effect of the spliced images are reduced.

Disclosure of Invention

The invention provides a projector, which comprises a light source, a light-equalizing element, a light valve and a light-permeable optical element. The light source can output an illumination beam, and the light equalizing element, the light valve and the optical element are arranged on a transmission path of the illumination beam. The optical element is arranged between the light valve and the light equalizing element and is positioned on the transmission path of the illumination light beam, the surface of the optical element is provided with a filter film, and the filter film is completely covered by the illumination light beam.

The invention provides a projector, which comprises an integrator, a light valve, an optical element and a filter, wherein the integrator, the light valve, the optical element and the filter are arranged on a transmission path of an illumination light beam. The optical element and the optical filter are arranged between the light valve and the integrator, and the effective filtering range of the optical filter is smaller than the illumination light beam range of the position of the optical filter.

The invention provides a projector, which can solve the problems that the brightness of a certain color in a partial area of an image is too high and the distribution of the intensity of other color lights is uneven by arranging a filter structure which can filter or weaken the color light with relatively strong intensity in a specific area on the surface of an optical element or between different optical elements, and meets the requirement of color uniformity specification. Moreover, when the plurality of projectors are used for splicing the television spliced wall images, the color of the spliced whole image is smooth and has better visual effect because each projected image has good color uniformity.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are specifically described below with reference to the accompanying drawings.

Drawings

Fig. 1 is a schematic view of a projector according to an embodiment of the present invention.

Fig. 2 is a schematic view of another embodiment of the projector according to the present invention.

Fig. 3 is a schematic view of another embodiment of the projector according to the present invention.

Fig. 4 is a schematic view of another embodiment of the projector according to the present invention.

Fig. 5 is a schematic view of another embodiment of the projector according to the present invention.

Fig. 6A and 6B show the distribution of the intensity regions of the respective colors with and without filtering with a red filter, respectively.

Detailed Description

Referring to fig. 1, fig. 1 is a schematic diagram illustrating a projector according to an embodiment of the invention. The projector 1 includes, in order along the transmission path of the illumination beam, a light source 10, a light equalizing element 12, a turning mirror 14, an optical element 16, a filter 20, an optical element 22, and a light valve 30, which are disposed on the transmission path of the illumination beam. The light source 10 provides an illumination beam I. The optical element 22 is disposed between the light valve 30 and the light equalizing element 12.

In this embodiment, the light source 10 can be a conventional thermoelectric light source, a fluorescent lamp, a light emitting diode, a laser light emitting diode or other device or element that can provide illumination light. In this embodiment, the light source 10 is a white light emitting diode module with fluorescent powder.

In the present invention, the term "light-homogenizing element" 12 refers to various elements or modules that can be used for homogenizing and homogenizing light, such as a lens array (LENS ARRAY), an integrator rod (INTEGRATE ROD), a rotatable prism, etc. In this example, the light equalizing element 12 is a solid integrating column.

In this example, the turning mirror 18 can be a flat, concave, or convex mirror; the reflecting surface can be an aspheric surface or a free-form surface. In this example, the turning mirror is a plane mirror, which can reflect the illumination light.

The term "optical element" as used herein means an element made of a material that is partially or completely reflective or transmissive, and typically comprises glass or plastic. For example, the optical element may be a lens, a total reflection Prism (TIR Prism), a total reverse reflection Prism set (RTIR Prism), various integrators, various filters, and the like. In the present embodiment, the optical element 16 is a biconvex lens with positive diopter and at least a portion of light passing therethrough.

In the present embodiment, the type of the filter 20 is not limited to a film shape, and may be an adhesive filter, a coating film, a filter or a doped optical surface, an optical surface or a device capable of filtering a specific wavelength, and the like. In this embodiment, the filter 20 is an optical film capable of filtering at least a portion of the wavelength in the red range, but the light that the filter 20 can filter is not limited to red, and can be, for example, blue light, green light, UV, IR or light with specific polarity.

In this embodiment, the optical element 22 may be a field lens, a total internal reflection PRISM (TIR PRISM) composed of a plurality of PRISMs, or a reverse total internal reflection PRISM set (RTIR PRISM) including a single PRISM. In the embodiment, the optical element 22 is a total internal reflection prism set formed by two full prisms, and each of the light incident surface and the light emitting surface of the optical element 22 is a plane.

The term Light valve 30 is widely used in the projection industry, and most of the industry refers to individual optical elements in a Spatial Light Modulator (SLM). A so-called spatial light modulator comprises a number of individual elements (individual optical elements) which are spatially arranged in a one-dimensional or two-dimensional array. Each unit can be independently controlled by optical signals or electric signals, and various physical effects (such as Pockels effect, Kerr effect, acousto-optic effect, magneto-optic effect, electro-optic effect of semiconductor, photorefractive effect, etc.) are utilized to change the optical characteristics of the unit, so that the illumination light beams illuminating on the independent units are modulated, and image light beams are output. The independent unit can be an optical element such as a micro-mirror or a liquid crystal unit. The light valve may be a Digital Micro-mirror Device (DMD), a Liquid Crystal On Silicon (LCOS) Panel, or a transmissive liquid crystal Panel.

In the Projector industry, projectors are generally classified into Cathode Ray Tube (Cathode Ray Tube) projectors, Liquid Crystal Display (LCD) projectors, Digital Light Projectors (DLP) and Liquid Crystal On Silicon (LCOS) projectors according to the difference of Light valves 30 used therein. The projector uses LCOS, DLP and other light valves to display images based on the principle of light reflection, so it is called a reflective projector. In the present embodiment, the projector is a digital light projector, and the light valve 30 is a Digital Micromirror Device (DMD).

In the present embodiment, the illumination beam I is converted into an image beam by the light valve 30 and then outputted through the optical element 22, and the filter 20 is disposed outside the transmission path of the image beam, which is a preferable design, and does not affect the image formation of the image beam. The filter 20 may be disposed at the light entrance surface of the optical element 22 (total reflection prism). As shown in fig. 1, an illumination beam I emitted from a light source 10 is homogenized by a light homogenizing element 12, passes through a lens L, enters a tir prism 22 via a filter 20, and is projected onto a light valve 30. The filter 20 can provide an effect of filtering or weakening specific color light, and if there is a problem that the color light intensity in a certain region of the image is too high and the periphery is weak, the filter 20 disposed on the surface of the tir prism 22 can weaken the intensity of the color light in the region, so as to improve the problem of uneven distribution of the color light intensity of the projected image.

For example, if the central RED light and the peripheral RED light of the image projected by the projector 10 are stronger, a RED light filter (dichroic mirror-RED) can be used to filter or attenuate the RED light passing through the tir prism 22 from the central portion and entering the light valve 30, so as to improve the color uniformity of the image.

Fig. 2 is a schematic diagram of a projector according to another embodiment of the invention. In this embodiment, the filter 20 of the projector 2 may be disposed on the light-facing surface LS of the lens 16 and located on the transmission path of the illumination light beam I. Although only a single lens 16 is schematically illustrated in fig. 2, it should be understood by those skilled in the art that a plurality of lenses may be disposed between the light equalizing element 14 and the light valve 30, and the optical element 22 having the filter 20 may be the lens 16 closest to the light valve 30 or the tir prism 22. The filter 20 disposed on the light-facing surface LS of the lens 16 can also reflect, absorb, or convert wavelength to filter or attenuate the color light with relatively strong intensity in a specific area, so that the color of the light entering different areas of the light valve is uniform. It should be noted that the forming position of the filter 20 on the lens 16 is not limited, and in another embodiment, the filter 20 may also be formed on the light emitting surface LS 'of the lens 16, or formed on different regions of the light facing surface LS and the light emitting surface LS' at the same time.

In the above embodiments, the filter 20 disposed on the surface of the optical element 22 can be completely covered by the illumination beam I. For example, as shown in fig. 1 and fig. 2, the filter 20 disposed on the surface of the optical device 22 completely falls within the region defined by the outermost edge MR of the light beam emitted by the light equalizing device 14. That is, if the illumination beam I forms a projection region on the extension plane of the filter 20 along the direction perpendicular to the optical axis, the edge MR of the projection region is as shown in fig. 1 and 2. The filter 20 falls completely within the projection area, and the total area of the filter 20 is smaller than the area of the projection area of the illumination beam I at the position of the filter 20.

Fig. 3 is a schematic diagram of a projector according to another embodiment of the invention. In the present embodiment, the projector 3 includes a light source 10, an integrator 12 ', a lens 16, a filter 20', a tir prism 22, and a light valve 30.

The term integrator 12' of the present invention, or light integrator, can be used for light homogenization. The integrator can be divided into two types, i.e., a lens array (LENS ARRAY) or an integrator column (INTEGRATE ROD). The integrating column type light integrator can be a rod or a column integrator with a hollow or non-hollow structure. And the lens array integrator may be a fly-eye lens. In this example, integrator 12' is a solid integrating column.

In the present embodiment, the light source 10 is an encapsulated white light emitting diode light emitting module with fluorescent powder, which provides an illumination beam I. The integrator 12', the light valve 30, the lens 16 and the tir prism 22 are arranged in the transmission path of the illumination beam I. A filter 20 'is disposed between the integrator 12' and the light valve 30 and is located on the transmission path of the illumination beam I. In this embodiment, the filter 20 ' may be located between the lens 16 and the tir prism 22, and the effective filtering range of the filter 20 ' is smaller than the illumination beam range at the position of the filter 20 '. The "effective filter range" refers to the entire region of the filter having a color filtering ability, and if the filter has a filtering ability at the periphery, the effective filter range is a part of the effective filter range even if no light passes through the filter. Furthermore, the illumination beam I can form a projection area on the extension plane of the optical filter 20 'along the direction perpendicular to the optical axis, and the projection area is the illumination beam range where the optical filter 20' is located. The filter 20' may also provide the effect of filtering or reducing the color light with relatively strong intensity in a specific area, so as to improve the color uniformity of the projected image. The position of the filter 20 'between the integrator 12' and the light valve 30 is not limited, and as shown in fig. 4, the filter 20 'may be disposed between the integrator 12' (or the turning mirror 14) and the lens 16 of the projector 4.

In the above embodiments, the type of the filter 20' is not limited to a sheet, and may be a film, a coating, a filter, etc., such as an attenuator, a color filter, a high-pass/low-pass filter, a band-pass filter, a dichroic mirror, etc., as examples. In this embodiment, the filter 20' is an attenuator that can proportionally filter the red light. Furthermore, the filter 20 'can be independently disposed and supported by a support 28 to be disposed in the optical path between the integrator 12' and the tir prism 22. The support 28 around the filter 20 'may be, for example, a transparent flat glass or a single support rod, and the support 28 may be integrally FORMED with at least a portion of the filter 20' (ONE PIECE electronic FORMED).

In one embodiment, the length of the filter 20 (or the filter 20') in the direction perpendicular to the optical axis is smaller than the clear aperture of the optical element (e.g., the lens 16) in front of the optical path, or the clear aperture of the optical element (e.g., the tir prism 22) in back of the optical path, or both. The term "clear aperture" as used herein refers to the diameter of a portion of the area where a lens or prism surface is formed to aid in the creation of optical performance. For example, the lens or prism may be formed with a flange (flange) or other structure in the peripheral region for positioning and assembly purposes, the positioning and assembly structure being located outside the optically effective diameter of the lens or prism. In addition, the light exit surfaces of the filter 20 and the filter 20' may be disposed on the optical path upstream of the optical device 16 or the optical device 22, or disposed before the light enters each of the

optical devices

16 and 22.

Moreover, the type of the color light to be filtered by the filter 20 (or the filter 20 ') and the filter area are not limited at all, and those skilled in the art can configure the filter 20 (or the filter 20') at a selected position in the light path according to actual requirements and apply the selected position to a desired environment to reduce the specific color light so as to achieve the effect of uniform image color. For example, as shown in FIG. 5, the filter 20 (or the filter 20 ') can be disposed on different optical elements on the optical path at the same time and can filter out different colors of light respectively, for example, the TIR prism 22 of the projector 5 can be glued with a red filter 20' on its surface to reduce red light, and a partial area of the surface of the lens 16 can be coated with a green filter 20 to reduce green light.

Fig. 6A and 6B show distribution diagrams of light intensity regions of respective colors with or without filtering by a RED light filter (dichroic mirror-RED), respectively, where the abscissa is different measurement position points from the center (0) to the outermost edge (18) of the image, the abscissa values 10 to 18 are measurement points at the outermost periphery of the image, and the ordinate is normalized intensity percentages of RED light (R), green light (G), blue light (B), and white light (W). The values in fig. 6A and 6B are normalized by taking the luminance at the center point of the image as the maximum value of 100%. It can be seen from fig. 6A that the red light in the corner regions of the image is weaker, so that a larger difference is generated with respect to the intensity of the green light/blue light, and the intensity distribution of the three color lights (RGB) on the image is more uniform as shown in fig. 6B due to the reduction of the maximum value of the red light in the central region of the image after filtering, thereby achieving the effect of uniform image color.

Through the design of the above embodiments, by arranging the filtering structure capable of filtering or weakening the color light with relatively strong intensity in the specific area on the surface of the optical element or between different optical elements, the problem that the brightness of a certain color in the image part area is too high and the distribution of the intensity of the color light is not uniform with that of other color light can be improved, and the requirements of color uniformity specifications are met. Moreover, when a television wall-piecing image is spliced by a plurality of projectors, because each projected image has good color uniformity, the color change of the spliced whole image is smooth and has better visual effect.

The invention may be practiced without these particulars. For example, in the above example, a smaller-scale filter is used to filter the red light in the middle of the illumination light to achieve uniform color intensity at the center and edge of the image. However, besides the red filter, a filter or a filter film for filtering other color lights can be used to achieve the corresponding effect. In addition, the filter or the filter film is not limited to be disposed at the center of the optical surface, and the position of the filter or the filter film can be adjusted as needed.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A projector, comprising:

a light source capable of outputting an illumination beam;

the light equalizing element is arranged on a transmission path of the illumination light beam;

the light valve is arranged on the transmission path of the illumination light beam; and

the light-permeable optical element is arranged between the light valve and the light equalizing element and is positioned on a transmission path of the illumination light beam, a filter film is arranged on the surface of the optical element and can filter or weaken color light with relatively strong intensity in a specific area, the effective filtering range of the filter film is in the illumination range of the illumination light beam at the position of the optical element, and the effective filtering range of the optical element is smaller than the illumination range.

2. The projector as claimed in claim 1, wherein the light transmissive optical element is a tir prism, and the filter film is disposed on a light incident surface of the tir prism.

3. The projector as claimed in claim 2, wherein the optical element is a lens, and the filter film is disposed on a surface of the lens.

4. A projector, comprising:

a light source capable of outputting an illumination beam;

the integrator is arranged on a transmission path of the illumination light beam;

the light valve is arranged on the transmission path of the illumination light beam;

the light-permeable optical element is arranged between the light valve and the integrator and is positioned on the transmission path of the illumination light beam; and

the optical filter is arranged between the light valve and the integrator and is positioned on the transmission path of the illumination light beam; the filter can filter out or weaken color light with relatively strong intensity in a specific area, and the effective filtering range of the filter is smaller than the range of the illumination light beam at the position of the filter.

5. The projector as claimed in claim 4, wherein the filter is glued to the optical element.

6. The projector as claimed in claim 4, wherein the light exit surface of the filter is disposed upstream in the optical path of the optical element.

7. The projector as claimed in claim 1 or 4, wherein the optical element is a prism.

8. The projector as claimed in claim 1 or 4, wherein a plurality of lenses are disposed between the light valve and the light source and in a transmission path of the illumination beam, and the optical element is a lens closest to the light valve among the plurality of lenses.

9. The projector as claimed in claim 4, wherein the filter is a red filter for filtering red light.

10. The projector according to claim 4, wherein the light source, the integrator, the filter, the optical element, and the light valve are included in this order along a transmission path of the illumination beam, and the integrator is an integration rod; the optical filter is a red light optical filter which can filter red light, and the optical element is a total reflection prism group and comprises two prisms; the light valve is a digital micromirror device.