TWI730451B - Projection system - Google Patents

Abstract

A projection system includes at least a light source, at least a dichroic filter element, and a light-adjusting diaphragm element. The light source is configured to emit a first color light having a spectrum of a first wavelength range and a second color light having a spectrum of a second wavelength range. One of the first color light and the second color light passes through the dichroic filter element or reflected by the dichroic filter element. The light-adjusting diaphragm element is disposed on the path after the first color light and the second color light are split, and the light-adjusting diaphragm element has a filter, wherein the first color light passes through the filter, and at least a part of energy of the second color light is blocked by the filter such that a transmittance of the spectrum of the first wavelength range is greater than a transmittance of the spectrum of the second wavelength range.

Description

Projection system

The present invention relates to a projection system, and more particularly to a projection system with a dimming diaphragm element.

In response to the current market trend towards lighter, thinner, shorter, and smaller electronic products, traditional projectors have also begun to develop towards miniaturization and high color performance. The mini projector is easy to carry around. It can not only be made into a portable mini projector, but also used in various existing electronic products, such as built-in mobile phones, multimedia players, notebook computers, etc., to expand the functions of electronic products. Sex.

In the projection system, the optical elements used to adjust the light of the light-emitting elements, such as light valves, lenses, etc., can be digital micro-mirror devices (DMD) or liquid crystal switch elements. In order to obtain optical high-brightness performance, current micro-projectors mostly use light-emitting diodes of the three primary colors of red, green, and blue as the light source, and directly project the three-color light to the digital micromirror device (DMD) for imaging.

In contrast detection, the human eye has the highest sensitivity to green light, which makes the green pattern look brighter and the contrast effect is more obvious. However, when detecting contrast, the high brightness of stray light will affect the overall contrast of the output image, making the image quality output by the projection system unable to be improved. At the same time, the color gamut of the image becomes smaller, so it cannot meet the DCI-P3 color gamut standard. Wide color gamut requirements.

The present invention relates to a projection system, which can reduce the dark field brightness of the image without affecting the color performance of the image, so as to improve the contrast of the image.

According to one aspect of the present invention, a projection system is provided, which includes at least one light source, at least one dichroic filter element, and a dimming shutter element. The light source is used for emitting a first color light and a second color light, the first color light has a spectrum in a first wavelength range, and the second color light has a spectrum in a second wavelength range. The dichroic filter element is used to transmit or reflect the first color light and the second color light. The dimming light barrier element is arranged on the path before or after combining the first color light and the second color light. The dimming light barrier element has a filter, wherein the first color light passes through the filter, and the second color light passes through the filter. At least part of the light energy of is blocked by the filter, so that the transmittance of the spectrum in the first wavelength range is greater than the transmittance of the spectrum in the second wavelength range.

According to one aspect of the present invention, a projection system is provided, which includes a first light source, a second light source, a light combining element, and a dimming shutter element. The first light source is used for emitting a first color light, and the first color light has a spectrum in a first wavelength range. The second light source is used for emitting a second color light, and the second color light has a spectrum in a second wavelength range. The combined light element is located on the light path of the first light source and the second light source, and is used for synthesizing the first color light and the second color light. The dimming diaphragm element is disposed between the second light source and the light-converging element. The dimming diaphragm element has a filter, wherein at least a part of the light of the second color light can be blocked by the filter to make the second wavelength The transmittance of the spectrum of the range is less than a set value.

In order to have a better understanding of the above and other aspects of the present invention, the following specific examples are given in conjunction with the accompanying drawings to describe in detail as follows:

The following examples are provided for detailed description. The examples are only used as examples for description, and are not intended to limit the scope of the present invention to be protected. In the following description, the same/similar symbols represent the same/similar elements. The directional terms mentioned in the following embodiments, for example: up, down, left, right, front or back, etc., are only the directions with reference to the accompanying drawings. Therefore, the directional terms used are used to illustrate but not to limit the present invention.

According to an embodiment of the present invention, a projection system is provided for projecting an image light on a screen. Generally speaking, the contrast ratio refers to the ratio of the brightness of the projector when projecting a completely white screen to the brightness of a completely black screen, or the ratio of the brightness of white to black areas when projecting a black/white screen. In order to improve the contrast, a dimming barrier element 140 (see Figures 2A and 2B) can be installed on the light path after combining or splitting light to reduce the amount of light entering the projection system 100 and make the dark field of the projection screen darker, thereby increasing The contrast and layering of the picture.

Please refer to Figures 1A and 1B, which respectively illustrate the transmittance diagrams of each color light wavelength, where the light source is used to emit a first color light and a second color light, and the first color light has a spectrum Wr in a first wavelength range , Wb, the second color light has a spectrum Wg in a second wavelength range. In an embodiment, the spectrum Wr, Wb of the first color light can pass through the filter material f1, and at least a part of the light of the second color light can be blocked by the filter material f1, so that the spectrum Wr, Wb of the first wavelength range The transmittance is greater than the transmittance of the spectrum Wg in the second wavelength range.

In one embodiment, the spectra Wr and Wb in the first wavelength range, for example, represent the wavelength range of blue and red light, and the second wavelength range Wg, for example, represents the wavelength range of the green or yellow light spectrum (495~570nm or 570nm). ~590nm). The blue and red light spectra corresponding to the first wavelength range can pass through the filter 143 of the dimming diaphragm element 140, and the energy of the yellow light spectrum or the green light spectrum corresponding to the second wavelength range can be blocked by the filter 143 and reduced . Since the blue light and red light spectrum will not be blocked by the filter 143, the light output energy of the blue light and red light spectrum will not be reduced. Of course, the projection system 100 of the present invention does not limit the reduction of the energy of the green or yellow light spectrum, and can also reduce the spectrum of other wavelength ranges.

Please refer to FIG. 2A. In one embodiment, the projection system 100 includes a plurality of light sources 110, a light combining element 101, and a dimming shutter element 140. The light source 110 is, for example, a light emitting diode, a laser diode, a metal halide bulb, a UHE bulb, or a UHP bulb, etc., which are suitable for lighting or optical projection, and are collectively referred to as a light emitting device, which emits color lights of different wavelength ranges. The co-optical component 101 has a semi-reflective/semi-transmissive coating film for reflecting or penetrating colored lights in different wavelength ranges. For example, the blue light Lb and the red light Lr corresponding to the first wavelength range can be reflected by the light combining element 101 to reach the dimming shutter element 140, and the green light Lg or yellow light corresponding to the second wavelength range can penetrate the light combining element. The dimming element 101 reaches the dimming diaphragm element 140. In addition, the dimming shutter element 140 is located on the path of the combined light of the blue light, red light and green light (that is, the first color light and the second color light), and is used to adjust the light energy of the green light or the yellow light (in terms of Lg' Said). In another embodiment, the dimming shutter element 140 can also be arranged between the light source 110 emitting green light and the light combining element 101 to adjust the light energy of the green light so that the green light spectrum Wg ( The transmittance of the spectrum corresponding to the second wavelength range is less than a set value.

Please refer to FIG. 2B. In one embodiment, the projection system 100 includes a light source 110, at least one dichroic filter element 102, and a dimming shutter element 140. The light source 110 is used to emit white light, and the dichroic filter element 102 is used to divide the white light into a plurality of color lights Lr, Lb, and Lg. The dichroic filter element 102 has a multi-color coating film for reflecting or penetrating colored lights of different wavelength ranges. For example, the blue light Lb and the red light Lr corresponding to the first wavelength range can respectively pass through the two dichroic filter elements 102, and the green light Lg or yellow light corresponding to the second wavelength range passes through the two dichroic filter elements in sequence 102 reflects and reaches the dimming shutter element 140. The dimming light barrier element 140 is located on the path of blue light, red light and green light (that is, the first color light and the second color light) after the light is split, and is used to adjust the light energy of the green light or the yellow light (Lg' represents the difference between Lg and Lg). Adjustment).

In addition, the color light emitted by the above-mentioned light source 110 can be adjusted via optical elements, such as a color wheel, a light pipe, a lens group, a total internal reflection lens (TIR PRISM), a lens with diopter (such as a field lens), a light valve, etc., please Refer to Figures 3A and 3B, which will not be repeated here.

The light valve can be a digital micro-mirror device (DMD), a liquid crystal switch device, or other devices or devices that can convert light emitted by a light-emitting device into image light and be driven by electrical energy, and are commonly used in digital projection systems.

The dimming diaphragm element can be arranged behind the lens to limit the diameter of the light beam passing through the lens. Generally speaking, the light barrier has a subtractive effect on the edge energy of the incident light, so as to prevent the edge energy of the incident light from being too high and affecting the contrast. Referring to FIGS. 3A and 3B, the projection system 100 of the present invention can purify the image light by arranging the dimming shutter element 141 in the appropriate light path, thereby improving the color performance of the image light.

The projection system 100 includes, for example, a light source 110, a filter device 112, a light pipe 114, at least one condenser lens 116, a reflector 118, a digital micromirror element 120, a projection lens 130, and a dimming shutter element. 141. The dimming shutter element 141 is disposed between the light source 110 and the projection lens 130. The position of the dimming shutter element 141 is, for example, at the position of point A in Figure 3A or the position of point B in Figure 3B. In one embodiment, the light pipe 114 is disposed between the light source 110 and the projection lens 130, and the light pipe 114 is used to limit the color light L to the light path leading to the projection lens 130. The condenser lens 116 is disposed between the light pipe 114 and the digital micro-mirror element 120. The reflecting mirror 118 is disposed between the condenser lens 116 and the digital micro-mirror element 120 to reflect the colored light L to the digital micro-mirror element 120.

The digital micro-mirror element 120 is located on the path after all the color lights L are combined, and includes a plurality of micro-mirrors (not shown in the figure), the angle of which can be adjusted. The micro reflector is used to reflect the colored light L to the projection lens 130 to become image light, or adjust the angle of the reflector surface to reflect the colored light L to the dark light path, so that the image light is not output. The dimming shutter element 141 is located at the position of the shutter behind the light pipe 114, that is, at the position of the shutter between the light pipe 114 and the projection lens 130. For example, in FIG. 3A, the dimming diaphragm element 141 is located at the diaphragm position between the light pipe 114 and the reflector 118 or the diaphragm position between the two condenser lenses 116. Alternatively, in FIG. 3B, the dimming diaphragm element 141 is located at the diaphragm position between the digital micromirror element 120 and the projection lens 130.

Please refer to FIG. 4A, the dimming shutter element 140 has a filter 143, and the filter 143 has a light shielding area 144 on the periphery of the filter 143. The shading area is an opaque area. The dimming light barrier element 140 is, for example, composed of a whole piece of filter element, and the light shielding area 144 is formed in a shielding manner. For example, the light-shielding area 144 is formed by coating, vapor-depositing, or pasting an opaque material. The opaque material is, for example, black matt paint.

In one embodiment, the filter 143 is composed of filter materials having different transmittances to green light or yellow light, for example. Please refer to Figure 1B, the first filter material f1 has a first transmittance to green or yellow light, and the second filter material f2 has a second transmittance to the spectrum of green or yellow light, and a third The filter material f3 has a third transmittance to green light or yellow light. The first penetration rate is less than the second penetration rate, and the second penetration rate is less than the third penetration rate. In this embodiment, filter materials f1, f2, and f3 with different transmittances can be respectively disposed on the filter 140, so that the transmittance of the spectrum Wg of green light or yellow light is outward from the center of the filter 140 Decrease or increase. For example, the penetration rate is reduced from 100% to 70%, and then from 70% to 50%, 20%, or 0%.

Referring to FIG. 4B, the center of the dimming shutter element 140 has an opening 142, for example. The shape of the opening 142 is, for example, a circle or other shapes, so as to completely penetrate all the colored lights, so as to increase the light output energy of the central area of the light barrier. In an embodiment, the dimming shutter element 140 is, for example, an opaque metal element, and a hole is punched out of the metal element, and then the filter 143 is embedded in the hole in an inlaid manner. An opening 142 is formed in the center of the filter 143 to allow the colored light to pass through completely. The filter 143 forms the opening 142 in a hollowed-out manner or a transparent material, for example.

Please refer to FIG. 4C, the filter 143 is located at the center of the dimming shutter element 140, for example, and the edge of the filter 143 has an opening 142. The opening 142 is formed of, for example, a light-transmitting material. The shape of the opening 142 is, for example, a circle, an ellipse, or other shapes, so as to completely penetrate the colored light around the filter 143 to increase the light output energy at the edge area of the light barrier. The opening 142 may also be formed in a hollowed manner, for example, and connect the filter 143 and the opaque area 144 by radial radiation, for example.

The function of the dimming shutter element 140 is like a combination of a diaphragm and a filter, and the first color light (corresponding to the blue and red light spectra Wr, Wb of the first wavelength range) can pass through the filter of the dimming shutter element 140 143 or opening 142, and at least part of the light energy of the second color light (corresponding to the yellow light spectrum or green light spectrum Wg of the second wavelength range) is blocked by the filter 143 or at least part of the light energy passes through the opening 142, so that the first wavelength The transmittance of the spectrum of the range is greater than the transmittance of the spectrum of the second wavelength range. Therefore, the projection system 100 disclosed in the above embodiment of the present invention can reduce the dark field brightness of the image without affecting the color performance of the image, so as to improve the contrast of the image.

At the same time, when detecting contrast, due to the decrease in the brightness of stray light, the overall contrast of the output image is relatively improved, so that the image quality output by the projection system is relatively improved. At the same time, the color gamut of the image is purified by the dimming diaphragm element to meet the DCI- The wide color gamut requirements of the P3 color gamut standard.

In summary, although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to those defined by the attached patent application scope.

100: Projection system 101: Heguang 稜鏡 element 102: Dichroic filter element 110: light source 112: Filtering device 114: Light pipe 116: Condenser lens 118: Mirror 120: Digital micromirror components 130: Projection lens 140, 141: Dimming diaphragm element 142: Opening 143: Filter 144: shading area L: all shades Lr: red light Lb: Blu-ray Lg, Lg’: green light Wr, Wb: the spectrum of the first wavelength range Wg: spectrum of the second wavelength range A, B: Barrier position f1: the first filter material f2: second filter material f3: third filter material

Figures 1A and 1B respectively show the transmittance diagrams of the wavelengths of each color light. FIG. 2A is a schematic diagram of a projection system with a composite light element according to an embodiment of the present invention. FIG. 2B is a schematic diagram of a projection system with dichroic filter elements according to an embodiment of the present invention. 3A and 3B respectively show schematic diagrams of the projection system according to the second embodiment of the present invention. FIG. 4A is a schematic diagram of a dimming diaphragm element of a projection system according to an embodiment of the invention. 4B and 4C are respectively schematic diagrams of the dimming diaphragm element of the projection system according to another embodiment of the present invention.

100: Projection system 101: Heguang 稜鏡 element 110: light source 140: Dimming diaphragm element Lr: red light Lb: Blu-ray Lg, Lg’: green light

Claims (18)

A projection system includes: At least one light source for emitting a first color light and a second color light, the first color light having a spectrum in a first wavelength range, and the second color light having a spectrum in a second wavelength range; At least one dichroic filter element for transmitting or reflecting the first color light and the second color light; and A dimming light barrier element is arranged on the path after the first color light and the second color light are split, the dimming light barrier element has a filter, wherein the first color light passes through the filter, the At least part of the light energy of the second color light is blocked by the filter, so that the transmittance of the spectrum in the first wavelength range is greater than the transmittance of the spectrum in the second wavelength range. In the projection system described in item 1 of the scope of patent application, the dimming diaphragm element has an opening in the center, and the filter is located at the outer edge of the opening. According to the projection system described in claim 1, wherein the filter is located at the center of the dimming barrier element, the dimming barrier element has an opening, and the opening is located at the outer edge of the filter. For the projection system described in item 2 or 3 of the scope of the patent application, the filter is hollowed out or a light-transmitting material is used to form the opening. In the projection system described in item 1 of the scope of patent application, the dimming shutter element is composed of a whole piece of filter element, and a shading area in the peripheral area of the filter is formed in a shading manner. According to the projection system described in item 1 of the scope of patent application, the transmittance of the spectrum of the second wavelength range decreases from the center of the filter to the outside. The projection system described in item 6 of the scope of patent application, wherein the filter is composed of filter materials having different transmittances for the second color light. For example, the projection system described in item 1 of the scope of patent application further includes a digital micro-mirror element arranged on the path after the first color light and the second color light are combined. As described in item 8 of the scope of patent application, the projection system further includes at least one condenser lens and a reflector. The reflector is arranged between the condenser lens and the digital micromirror element to reflect the first color The light and the second color light reach a plurality of micro-reflecting mirror surfaces of the digital micro-mirror element. A projection system includes: A first light source for emitting a first color light, the first color light having a spectrum in a first wavelength range; A second light source for emitting a second color light, the second color light having a spectrum in a second wavelength range; A combined light source element located on the light path of the first light source and the second light source for synthesizing the first color light and the second color light; and A dimming light barrier element is arranged on the light path after the first color light and the second color light are combined, or between the second light source and the light combining element, the dimming light barrier element has a filter Wherein at least a part of the light energy of the second color light is blocked by the filter, so that the transmittance of the spectrum of the second wavelength range is less than a set value. According to the projection system described in item 10 of the scope of patent application, wherein the center of the dimming shutter element has an opening, and the filter is located at the outer edge of the opening. According to the projection system described in claim 10, the filter is located at the center of the dimming shutter element, the dimming shutter element has an opening, and the opening is located at the outer edge of the filter. For the projection system described in item 11 or 12 of the scope of the patent application, the filter is hollowed out or a transparent material is used to form the opening. In the projection system described in item 10 of the scope of patent application, the dimming shutter element is composed of a whole piece of filter element, and a shading area in the peripheral area of the filter is formed in a shading manner. According to the projection system described in item 10 of the scope of patent application, the transmittance of the spectrum of the second wavelength range decreases from the center of the filter to the outside. The projection system described in item 15 of the scope of patent application, wherein the filter is composed of filter materials having different transmittances for the second color light. For example, the projection system described in item 10 of the scope of patent application further includes a digital micro-mirror element, which is arranged on the path where the first color light and the second color light are combined. The projection system described in item 17 of the scope of patent application further includes at least one condensing lens and a reflecting mirror. The reflecting mirror is disposed between the condensing lens and the digital micro-mirror element to reflect the first color. The light and the second color light reach a plurality of micro-reflecting mirror surfaces of the digital micro-mirror element.

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