TWI829447B - Projection device - Google Patents

Abstract

A projection device includes a light source, a light homogenization element, an LCD panel and a projection lens. The light homogenization element is disposed downstream. The light homogenization element has a light-emitting surface and a light incident surface at two ends. A cross-section of the light homogenization element crosses an edge of the light incident surface to form a first point and crosses an edge of the light-emitting surface to form a second point. At least a part of a track between the first point and the second point through a reflective surface of the light homogenization element is an arc line.

Description

projection device

The invention relates to a projection device.

Due to space and cost constraints, current LCD projectors often use a single light-emitting diode as the projector's light source. Therefore, it is easy to have poor uniformity problems in which the center area of the screen is too bright and the corners are dark.

According to one aspect of the present invention, a projection device is provided, which includes a light source, a light uniformity element, a liquid crystal panel and a projection lens. The light uniformity element is located downstream of the light path of the light source and has a light incident surface and a light exit surface at both ends. The intersection point of a section of the light uniformity element and the edge of the light incident surface is the first intersection point, and the intersection point of the cross section and the edge of the light exit surface is a second intersection point, and at least part of the trajectory from the first intersection point along the reflective surface of the light uniform element to the second intersection point is an arc. The liquid crystal panel is disposed downstream of the optical path of the light uniformity element, and the projection lens is disposed downstream of the optical path of the liquid crystal panel.

According to the above-mentioned viewpoint of the present invention, the light uniformity element with a curved reflective surface can disperse the light more evenly to various areas of the liquid crystal panel, so it can improve the problem that the brightness of the center area of the screen is higher than that of the corners. Furthermore, by adjusting the curvature of different sections of the arc-shaped reflective surface, the light emission angle can be flexibly changed. Therefore, the curvature of different sections of the arc-shaped reflective surface can be adjusted according to different needs, such as according to the light emission characteristics of the light source matched with the light uniformity component. To further improve the brightness uniformity of the projected image.

In order to make the present invention more obvious and understandable, the following examples are used to describe the invention in detail with reference to the accompanying drawings.

1, 2, 3: Projection device

10, 40: light source

10a: White light emitting diode module

101:Light-emitting diode chip

102:Fluorescent layer

12: Light uniformity component

12a, 42: Integrating column

12b: Lens

14: Semi-penetrating half-reflecting mirror

14a: Spectral coating

16, 46: Polarizing plate

18, 48: LCD panel

22: Steering mirror

24:Projection lens

32, 34: Fresnel lens

42a: light incident surface

42b: light-emitting surface

42c: Section

AS, AS1, AS2, AS3: arc reflective surface

I, I1, I2: light

IB: Blu-ray

IM: image light

IW: white light

PS: Plane reflective surface

P, Q: intersection point

S: arc

FIG. 1 is a schematic diagram of a projection device according to an embodiment of the present invention.

FIG. 2 shows a light transmittance curve of a transflective element and a light source according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a projection device according to another embodiment of the present invention.

FIG. 4 is a schematic diagram of a projection device according to another embodiment of the present invention.

FIG. 5 is a schematic diagram of a projection device according to another embodiment of the present invention.

Figure 6A and Figure 6B respectively show the brightness uniformity performance of the integrating column with a curved reflective surface and a flat reflective surface.

FIG. 7 is a schematic diagram of a projection device according to another embodiment of the present invention.

FIG. 8 is a schematic diagram of a projection device according to another embodiment of the present invention.

The foregoing and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of multiple embodiments with reference to the drawings. In addition, the terms "first" and "second" used in the following embodiments are used to identify the same or similar components, and directional terms such as "front" and "rear" are only for reference to the attached drawings. Directions are not intended to limit the elements described.

FIG. 1 is a schematic diagram of a projection device according to an embodiment of the present invention. In the projection device 1 of this embodiment, the light source 10 emits light I, and the traveling path of the light I may include a light uniform element 12, a transflective element 14, a polarizing plate 16, a liquid crystal panel 18, and a turning mirror in order. 22 (folding mirror) and projection lens 24. The light source 10 and the light uniformity element 12 can be two separate elements separated by a distance from each other, and the light uniformity element 12 can be, for example, an integrating rod, a fly's eye lens array, a diffuser, etc. without limitation. The light source 10 can be a traditional thermoelectric light source, a fluorescent lamp, a light-emitting diode, a laser light-emitting diode light-emitting element, or other devices or elements that can provide illumination light. Furthermore, a Fresnel lens 32 can be disposed in the optical path between the liquid crystal panel 18 and the turning mirror 22 , and another Fresnel lens 34 can be disposed in the optical path between the transflective element 14 and the polarizing plate 16 .

In this embodiment, the light source 10 can be a packaged white light-emitting diode module 10a having a light-emitting diode chip 101 and a phosphor layer 102. The phosphor layer 102 is located in the optical path of the light-emitting diode chip 101. Downstream, the transflective element 14 is located downstream of the optical path of the phosphor layer 102 . The transflective element 14 can partially reflect and partially transmit light within a specific wavelength range, for example, it can reflect part of the blue light and allow part of the blue light to pass through, and the liquid crystal panel 18 is located downstream of the penetrating light path of the transflective element 14 . As shown in Figure 1, when the white light IW emitted by the white light emitting diode module 10a is uniformized by the light uniform element 12 and incident on the semi-transparent and semi-reflective element 14, part of the blue light IB in the white light IW can be semi-transmitted. The semi-reflective element 14 reflects back onto the phosphor layer 102, thereby re-exciting the phosphor material in the phosphor layer 102, thereby increasing the brightness of the white light emitting diode module 10a. The white light IW with enhanced brightness can continue to be converted into image light IM through the polarizing plate 16 and the liquid crystal panel 18 , and the image light IM is deflected by the turning mirror 22 and then enters the projection lens 24 . Furthermore, the Fresnel lenses 32 and 34 can be used to focus and collimate the light ray I and the image light IM respectively. In another embodiment, other optical elements with light concentrating and collimating light effects can also be used to replace the Fresnel lenses. The ear lenses 32 and 34 are not limited.

In this embodiment, the transflective element 14 can be a see through mirror, or can also be a blue light splitter that only reflects part of the blue light. For example, as shown in FIG. 2 , the transflective element 14 can have a blue light transmittance of about 50%, so that part of the blue light can be transmitted and part of the blue light can be reflected back to the phosphor layer 102 to excite the phosphor material again. , thereby increasing the brightness of the white light emitting diode module 10a. The following table shows a comparison of the optical performance of this embodiment using a transflective element with a blue light transmittance of about 50% and a conventional design without a transflective element. It can be seen from the table below that this embodiment can provide the effects of increasing brightness (the central illumination is increased to 189.6 lux) and improving color temperature (the color coordinate values Wx and Wy are higher than conventional designs). The central illuminance here is measured as the average illuminance within a 35mm diameter range with the center of the circle as the center, and a higher central illuminance value can represent an increase in the overall brightness of the screen.

According to the design of the above embodiment, by partially transmitting and partially reflecting light within the wavelength range that can excite the fluorescent material, the light reflected back to the light source can excite the fluorescent material of the light source again, thereby achieving the effect of increasing the brightness of the light source. Furthermore, by adjusting the light transmission ratio of the transflective and semi-reflective elements, the color temperature can be adjusted, thereby improving the color uniformity of the projected image.

FIG. 3 is a schematic diagram of a projection device according to another embodiment of the present invention. In the projection device 2 of this embodiment, an integrating rod 12a and a lens 12b can be used as the light uniformity element 12 at the same time. The lens 12b can also provide light collection or beam shaping effects, and can be directly plated on the surface of the lens 12b. A layer of blue light splitting coating 14a can also provide the effect of reflecting part of the blue light band back to the light source 10. It should be noted that the above-mentioned wavelength-selective dichroic coating 14a is not limited to being provided on the lens 12b, but can also be provided on other components between the light source 10 and the liquid crystal panel 18, as long as it does not affect the original function of the component. Furthermore, in another embodiment, the integrating rod 12 a can also be omitted and only at least one lens 12 b is used as the light uniformity element 12 .

It should be noted that the above-mentioned blue light band light that is partially reflected back to the light source is only an example. The semi-transmitting and semi-reflective element 14 can be a spectroscopic element used to reflect light in other wavelength ranges (such as ultraviolet light) that has energy to excite fluorescent materials. Furthermore, the arrangement position and area of the transflective element 14 relative to the light source 10 in space are not limited, and the transmittance of the transflective element 14 in different areas can also be changed to further improve the brightness of the screen. Uniformity.

Furthermore, an embodiment of the present invention can provide a method for manufacturing a projection device, which includes the following steps. First, a housing is provided and a light-emitting diode chip and a phosphor layer are installed in the housing. The semi-transmitting half-reflecting mirror is disposed downstream of the light path of the light-emitting diode chip, and the fluorescent layer is disposed in the light path between the light-emitting diode chip and the semi-transmitting half-reflecting mirror. Furthermore, a liquid crystal panel and a projection lens are installed in the housing, and the liquid crystal panel is located in the light path between the semi-transparent mirror and the projection lens.

FIG. 4 is a schematic diagram of a projection device according to another embodiment of the present invention. In this embodiment, the light uniformity element of the projection device 3 is an integrating rod 42, and the integrating rod 42 and the integrating rod 42 in FIG. 3 The main difference between the pillars 12a is that the integrating pillar 42 has an arcuate reflective surface. As shown in FIG. 4 , the integrating post 42 and the light source 40 are two separate components separated by a distance and located downstream of the light path of the light source 40 , and a liquid crystal panel 48 is located downstream of the light path of the integrating post 42 . The two ends of the integrating rod 42 are a light-incident surface 42a and a light-emitting surface 42b. The intersection point of a cross-section 42c of the integrating rod 42 and the edge of the light-incident surface 42a is the first intersection point P. The intersection point of the same cross-section 42c and the edge of the light-emitting surface 42b is is the second intersection point Q, and at least part of the trajectory of the first intersection point P along the reflection surface of the integrating rod 42 to the second intersection point Q is an arc S. Furthermore, as shown in FIG. 4 , the reflective surface S of the integrating rod 42 is arranged along the optical axis of the projection device 3 and presents a quasi-hemispherical shape with an outward protruding curve. Please refer to FIG. 5 . FIG. 5 illustrates the arc-shaped reflective surface AS of the integrating post 42 compared with the planar reflective surface PS of the integrating post 12 a. For example, when the light ray I is reflected by the arc-shaped reflective surface AS, a light ray I1 will be formed and directed toward the liquid crystal. It travels in the direction of the panel 48, and if the light ray I is reflected by the flat reflective surface PS, it will form a light ray I2 and travel in the direction of the liquid crystal panel 48. Comparing the traveling directions of the light ray I1 and the light ray I2, it can be seen that the arc-shaped reflective surface AS can provide the direction of the incident light to the opposite direction. The effect of deflection in a direction away from the center of the liquid crystal panel 18 can avoid the problem of over-brightness in the center of the screen and dark brightness in the corners, thereby improving the brightness uniformity of the screen. Furthermore, please refer to Figure 5 again. In one embodiment, each point of the arc-shaped reflective surface AS preferably falls within the 80-degree angle range of the line connecting the two intersection points P and Q, in order to obtain better light. deflection effect. Furthermore, in one embodiment, the shortest straight line length of the two intersection points P and Q may be more than 5 mm. It should be noted that the reflective surface or reflective surface of this light uniform element can be an outer surface or an inner surface without limitation. For example, if the light uniform element is a hollow integrating cylinder, the term "reflective surface (reflective surface)" can mean light uniformity. The inner surface of the element, and if the light uniformity element is a solid integrating column with a reflective film on the outer layer, the term "reflective surface (reflective surface)" can also refer to the outer surface of the light uniformity element.

Figure 6A and Figure 6B respectively show the brightness uniformity performance of the integrating column with a curved reflective surface and a flat reflective surface. In FIGS. 6A and 6B , the graph on the bottom side shows the brightness distribution of the liquid crystal panel 48 measured along the line A-A', and the graph on the right side shows the brightness distribution of the liquid crystal panel 48 measured along the line B-B'. Comparing Figure 6A and Figure 6B, it can be seen that the image brightness of the integrating column with arc-shaped reflective surface AS (Figure 6A) is compared with the image brightness of the integrating column with flat reflective surface PS (Figure 6B). The brightness distribution of the integrating column of AS is relatively uniform and does not cause over-brightness in the central area and corners. The problem of the landing area being dark.

Furthermore, the structure and arrangement of the above-mentioned integrating pillar with a curved reflecting surface are not limited at all. For example, as shown in FIG. 7 , the light source 40 can be disposed in the optical path between the integrating column 42 and the liquid crystal panel 48 , and each arc-shaped reflective surface AS1 - AS3 of the integrating column 42 can substantially surround the light source 40 , and the light source 40 emits The light I can be first reflected from the arc-shaped reflective surface AS1 on the opposite side to the arc-shaped reflective surfaces AS2 and AS3 above and below, and then reflected to the liquid crystal panel 48 by the arc-shaped reflective surfaces AS2 and AS3. Since the light emitting direction of the light source 40 is facing away from the liquid crystal panel 48 and the light ray I can first be reflected by the arc-shaped reflective surface AS1 to provide a light diffusion effect, good picture brightness uniformity can be provided. Furthermore, as shown in FIG. 8 , a lens 46 can also be disposed between the light source 40 and the integrating rod 42 . The light emitted by the light source 40 can first be expanded or shaped by the lens 46 and then incident on the arc-shaped reflective surface AS to obtain Improve the overall picture uniformity.

An embodiment of the present invention provides a method for manufacturing a projection device, which includes the following steps. Firstly, a casing is provided and a light source and a light uniformity element are installed in the casing, and the light uniformity element is arranged downstream of the light path of the light source. The two ends of the light uniform element are a light incident surface and a light exit surface. The intersection point of a section of the light uniform element and the edge of the light incident surface is the first intersection point, the intersection point of the section and the edge of the light exit surface is the second intersection point, and the first intersection point At least part of the trajectory of the intersection point along the reflective surface of the light uniform element to the second intersection point is an arc. Furthermore, a liquid crystal panel and a projection lens are installed in the housing. The liquid crystal panel is located downstream of the optical path of the light uniform component, and the projection lens is located downstream of the optical path of the liquid crystal panel.

Through the design of each of the above embodiments, the light uniformity element with a curved reflective surface can disperse light more evenly to various areas of the liquid crystal panel, thereby improving the problem that the brightness of the central area of the screen is higher than that of the corners. Furthermore, by adjusting the curvature of different sections of the arc-shaped reflective surface, the light emission angle can be flexibly changed. Therefore, the curvature of different sections of the arc-shaped reflective surface can be adjusted according to different needs, such as according to the light emission characteristics of the light source matched with the light uniformity component. To further improve the brightness uniformity of the projected image.

It should be noted that the integrating rod in the above embodiment is only an example. It only needs to provide a reflective curved surface to produce the effect of dispersing light to various image areas. The structure or composition of the light uniformity element is not limited at all. Furthermore, the arrangement of the arc-shaped reflective surface of the light uniformity element relative to the light source in space, The curvature or area can be changed according to actual needs without limitation.

Although the present invention has been disclosed above in terms of preferred embodiments, they are not intended to limit the present invention. Anyone skilled in the art may make some modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be subject to the scope of the patent application attached.

3: Projection device

40:Light source

42: Integrating column

42a: light incident surface

42b: light-emitting surface

42c: Section

48:LCD panel

P, Q: intersection point

S: arc

Claims (10)

A projection device, including: a monochromatic light-emitting diode light source; a single light-uniform element capable of condensing and collimating light, located downstream of the light path of the monochromatic light-emitting diode light source, wherein both ends of the single light-uniform element It is a light incident surface and a light exit surface, the intersection point of a cross section of the single light uniform element and the edge of the light entrance surface is the first intersection point, the intersection point of the cross section and the edge of the light exit surface is the second intersection point, and the third intersection point At least part of the trajectory of an intersection point from the reflective surface of the single light uniform element to the second intersection point is an arc, wherein the reflective surface of the single light uniform element is arranged along the optical axis of the projection device to present a quasi-hemisphere with an outward protruding curve. shape; a liquid crystal panel, located downstream of the optical path of the single light uniform element; and a projection lens, located downstream of the optical path of the liquid crystal panel. For the projection device described in item 1 of the patent application, the single light uniformity element is a single integrating rod. For the projection device described in item 1 of the patent application, the monochromatic light-emitting diode light source is a white-light light-emitting diode module. For the projection device described in item 1 of the patent application, the light emitting direction of the monochromatic light-emitting diode light source is facing away from the liquid crystal panel. The projection device as described in item 1 of the patent application further includes: a lens disposed in the optical path between the monochromatic light-emitting diode light source and the single light uniform element. A projection device, including: a monochromatic light-emitting diode module; a single integrating column that can condense and collimate light, including at least one arc-shaped reflective surface. The shortest length of the arc-shaped reflective surface is more than 5 mm. The single integrating column The arc-shaped reflective surface of the integrating pillar is arranged along the optical axis of the projection device to present a quasi-hemispheric shape with an outward protruding curve, and the single integrating pillar is located downstream of the optical path of the light-emitting diode module; a liquid crystal panel is located on downstream of the single integrating column; and A projection lens is located downstream of the optical path of the liquid crystal panel. For the projection device described in Item 6 of the patent application, the single integrating column includes a plurality of arc-shaped reflective surfaces, and the arc-shaped reflective surfaces substantially surround the monochromatic light-emitting diode module. The projection device described in Item 6 of the patent application further includes: a lens disposed in the optical path between the monochromatic light-emitting diode module and the single integrating column. As for the projection device described in item 6 of the patent application, different sections of the arc-shaped reflective surface have different curvatures. For the projection device described in item 6 of the patent application, the single-color light-emitting diode module is a white-light light-emitting diode module.

Images