TWI676856B - Projection system - Google Patents

Abstract

A projection system includes a light source, a projection lens, and a dimming light barrier element. The light source is used for emitting a first light, and the first light has a first dominant wavelength range and a second dominant wavelength range. The projection lens is disposed on a path of the first light. The dimming light barrier element is disposed between the light source and the projection lens. The dimming light barrier element has an opening and a light blocking area located outside the opening. A filter is arranged in the opening, and part of the first light is blocked by the light blocking area. Of the remaining first rays that pass through the opening, the band corresponding to the first main wavelength range passes through the opening, and the band of the second main wavelength range is blocked by the filter to become a second light, so that the second light has a narrow width relative to the first light. Wavelength range.

Description

Projection system

The invention relates to a projection system, and in particular to a projection system with a wide color gamut image output.

In response to the current trend of light, thin, short, and small electronic products in the market, traditional projectors have also begun to develop toward miniaturization and high color performance. Mini projectors are easy to carry around, not only can be made into portable mini projectors, but also applied to various existing electronic products, such as built-in mobile phones, multimedia players, notebook computers, etc., to expand the functions of electronic products Diversity.

In the projection system, optical elements such as light valves and lenses used to adjust the light of the light-emitting elements can be digital micro-mirror devices (DMDs) and liquid crystal switching elements. For optically high-brightness performance, micro projectors currently use light-emitting diodes of three primary colors of red, green, and blue as the light source, and directly project the three-color light onto a digital micromirror element (DMD) for imaging.

However, in terms of color performance, too high yellow light energy will affect the position of the color coordinates of the green light output, making the color gamut of the image output by the projection system smaller, and the color of the green light output being yellowish, resulting in chromatic aberration, so it cannot meet the DCI. -Wide color gamut requirements for the P3 color gamut standard.

The invention relates to a projection system, which can purify image light to improve the color performance of the image light.

According to an aspect of the present invention, a projection system is provided, which includes a light source, a projection lens, and a dimming light barrier element. The light source is used for emitting a first light, and the first light has a first dominant wavelength range and a second dominant wavelength range. The projection lens is disposed on a path of the first light. The dimming light barrier element is disposed between the light source and the projection lens. The dimming light barrier element has an opening and a light blocking area located outside the opening. A filter is arranged in the opening, and part of the first light is blocked by the light blocking area. Of the remaining first rays of light passing through the opening, the band corresponding to the first main wavelength range passes through the opening, and the band of the second main wavelength range is blocked by the filter to become the second light, so that the second light has a narrow width relative to the first light. Wavelength range.

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

The following is a detailed description of an embodiment. The embodiments are only used as examples and are not intended to limit the scope of the present invention. The following uses the same / similar symbols to indicate the same / similar components for explanation.

This embodiment provides a projection system for projecting an image light on a screen. As shown in FIG. 2A, the projection system 100 includes a light source 110, such as a light emitting diode, a laser diode, a metal halide bulb, a UHE bulb, or a UHP bulb, which are suitable for lighting or optical projection, and are collectively referred to as light emitting. element. In addition, the light emitted by the light-emitting element can also be adjusted through an optical element. The optical element may include a collimating lens, a light-equalizing element (such as a lens matrix, an integrating column), a projection lens, and the like. In addition, the light emitted by the light emitting element can be adjusted by other optical elements, such as a filter device (such as a color wheel, a color filter), a beam splitter, a TIR PRISM, and a lens having a refractive power (such as Field lens) or other optical elements that can adjust the light of the light emitting element (such as a light valve or a light barrier, which can also be called an aperture).

The light valve can be a digital micromirror element (DMD), a liquid crystal switching element, or other elements or devices that can convert light emitted from the light emitting element into image light and is driven by electrical energy. It is commonly used in digital projection systems.

The light barrier is arranged behind the lens to limit the diameter of the light beam passing through the lens. In general, the light bar has a reducing effect on the edge energy of the incident light, and avoids the edge energy of the incident light being too high to affect the contrast. Please refer to FIGS. 2A and 2B. The projection system 100 of the present invention can provide a dimming light barrier element 140 in an appropriate optical path, so that a band of a specific main wavelength range passes through the opening 142 and blocks (for example, a filter 143). Filtering out) another wavelength band of the main wavelength range to purify the image light, thereby improving the color performance of the image light.

As shown in FIGS. 4 and 5, the dimming light barrier element 140 is composed of, for example, a whole piece of filter element 141, and a light-shielding region 144 is formed on the filter element in a shielding manner, leaving only the opening 142 to transmit light. For example, the light-shielding region 144 is formed by applying, vapor-depositing, or pasting an opaque material. The opaque material is, for example, a black matte paint. Alternatively, in another embodiment, the dimming light barrier element 140 is, for example, an opaque metal element, and the opening 142 is punched out from the metal element, and the filter 143 is embedded in the opening 142 in a mosaic manner. As shown in FIGS. 4 and 5, the dimming light barrier element 140 has an opening 142 and a light-shielding region 144 located outside the opening 142. A filter 143 is provided in the opening 142. The light-shielding region 144 can block part of the incident light (dotted line). The area represents the cross-sectional profile AC of the incident light) and a part of the incident light passes through the opening 142. The filter 143 may be a part of the entire filter element 141 or only an element embedded in the opening 142. In this embodiment, the cross-sectional diameter of the incident light is larger than the diameter of the opening 142.

Please refer to FIG. 1A and FIG. 1B, which respectively show schematic diagrams of transmittance of light wavelengths of different colors. The first light L1 emitted from the light emitting element includes a first main wavelength range W1 and a second main wavelength range W2. In an embodiment, the filter 143 of the dimming light barrier element 140 passes the band corresponding to the first main wavelength range W1 in the first light L1 emitted by the light-emitting element through the opening 142 and blocks the corresponding light in the first light L1. The two main wavelength ranges W2 become the second light L2, so that the second light L2 has a narrow wavelength range relative to the first light L1.

In an embodiment, the first main wavelength range W1 is, for example, a 550nm wavelength range representing a green light wavelength, and the second main wavelength range W2 is, for example, a 570nm wavelength range representing a yellow light wavelength. The green light energy band corresponding to the first main wavelength range W1 can pass through the opening 142 of the dimming light barrier element 140, while the yellow light energy band corresponding to the second main wavelength range W2 is blocked by the filter 143 and reduced. Therefore, the projection system 100 can accurately output the purified green light energy band to approximate the true color performance, and then meet the wide color gamut requirements of the DCI-P3 color gamut standard. Of course, the projection system 100 of the present invention is not limited to purifying the incident light in the green light energy band, but may also purify the incident light in the blue light energy band Wb or the red light energy band Wr.

Please refer to FIGS. 2A and 2B, which are schematic diagrams of a projection system 100 according to two embodiments of the present invention, respectively. 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 light barrier element 140. As shown in FIG. 4, the dimming light barrier element 140 has an opening 142 and a light shielding region 144 located outside the opening 142. The shape of the opening 142 is, for example, circular, and the edge of the opening 142 has, for example, a concave contour 141 b (see FIG. 4) or a ring-shaped contour 141 c (see FIG. 5) to block part of the first light L1. The dimming light barrier element 140 is disposed between the light source 110 and the projection lens 130. The position of the dimming light barrier element 140 is, for example, a point A position in FIG. 2A or a point B position in FIG. 2B.

The light source 110 is configured to emit a visible light L (for example, white light or monochromatic light). The projection lens 130 is disposed on the path of the first light L1. The visible light L can be filtered by the filtering device 112 (such as a color wheel or a filter) to become a first light L1 (the first color light). The first light L1 (the first color light) passes through the light pipe 114 and is adjusted by the condenser lens 116, the mirror 118, and the digital micromirror element 120 to reach the projection lens 130 to form the image light required for projection. . Of course, the light source 110 can also directly emit the first light L1 (the first color light) without going through the light pipe 114 or the filtering process.

As shown in FIGS. 1A and 1B, the first light ray L1 has a first dominant wavelength range W1 and a second dominant wavelength range W2. The band corresponding to the first main wavelength range W1 in the first light L1 can pass through the opening 142 of the dimming barrier element 140 and block the band corresponding to the second main wavelength range W2 in the first light L1 to become a second light L2. The second light L2 has a narrow wavelength range relative to the first light L1.

In one embodiment, the light pipe 114 is disposed between the light source 110 and the projection lens 130. The light pipe 114 is used to limit the first light L1 to the light path leading to the projection lens 130. The condenser lens 116 is disposed between the light pipe 114 and the digital micromirror element 120. The reflecting mirror 118 is disposed between the condenser lens 116 and the digital micromirror element 120 to reflect the first light L1 or the second light L2 to the digital micromirror element 120.

The digital micromirror element 120 is disposed on a light path from the first light L1 or the second light L2 to the projection lens 130. The digital micromirror element 120 includes a plurality of micro-reflective mirror surfaces (not shown), and the angle thereof can be adjusted. The surface of the micro-mirror 118 is used to reflect the first light L1 or the second light L2 to the projection lens 130 to become image light, or the angle of the mirror surface is adjusted so that the first light L1 or the second light L2 is reflected to the dark light path, so No image light is output.

The dimming light barrier element 140 is located at the light barrier position behind the light pipe 114, that is, at the light barrier position between the light pipe 114 and the projection lens 130. For example, in FIG. 2A, the dimming light barrier element 140 is located at the light barrier position between the light pipe 114 and the reflector 118 or the light barrier position between the two condenser lenses 116. At least one condenser lens 116 is located between the light pipe 114 and the digital micromirror element 120. Alternatively, in FIG. 2B, the dimming light barrier element 140 is located at the light barrier position between the digital micromirror element 120 and the projection lens 130.

Please refer to FIG. 3, which is a schematic diagram illustrating a position of a dimming light barrier element 140 according to another embodiment of the present invention. In this embodiment, the projection system 100 may further include an imaging lens group 132, which is disposed between the projection lens 130 and the reflector 118. The dimming light barrier element 140 is, for example, located at the position of the light barrier between the projection lens 130 and the imaging lens group 132, and can purify the first light L1 and block part of the first light L1, so that The second light L2 of the opening 142 has a narrow wavelength range.

The above-mentioned projection lens 130 may be composed of at least one optical lens for adjusting the image light output from the digital micromirror element 120 and projected on the screen. In addition, the projection system 100 of the present invention covers the aforementioned light source 110, filter device 112, condenser lens 116, dimming light barrier element 140, reflector 118, digital micromirror element 120, and projection with a casing or a cover. Elements such as the lens 130 only expose the light-emitting surface of the projection lens 130 to the casing, so that the image light is projected outside the casing.

Referring to FIG. 4, the opening 142 of the dimming light barrier element 140 is not limited to a circle, and may be other geometric patterns, such as a square opening, a rectangular opening, a drop shape, an oval shape, a diamond shape, a fan shape, or other shapes. In addition, the opening 142 of the dimming light barrier element 140 has an outwardly convex profile 141a and an inwardly concave profile 141b, like a non-circular opening with a notch. In FIG. 4, parts other than the opening 142 are opaque.

Referring to FIG. 5, in another embodiment, the light-shielding region 144 surrounds the periphery of the opening 142, for example, so that the middle portion becomes a circular, elliptical or other shape light-transmitting region. In FIG. 5, parts other than the opening 142 are opaque. The outline of the opening 142 is not limited to a circle, and may be an ellipse or other shapes.

The function of the dimming light barrier element 140 is like a combination of a light barrier and a filter. The first light L1 emitted by the light emitting element corresponding to the first main wavelength range W1 (for example, the green wavelength 550nm wavelength range) can be dimmed The opening 142 of the light barrier element 140 filters a wavelength band of a wavelength range of 570 nm, for example, a wavelength of yellow light. Therefore, the projection system 100 disclosed in the above embodiments of the present invention can accurately output the purified green light energy band to approximate the true color performance, thereby meeting the wide color gamut requirements of the DCI-P3 color gamut standard.

In addition, the projection system 100 disclosed in the above embodiments of the present invention can reduce the edge energy of part of the incident light to form a dark field, thereby improving the contrast of colors.

In summary, although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains 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 determined by the scope of the attached patent application.

100‧‧‧ projection system

110‧‧‧light source

112‧‧‧ Filter Device

114‧‧‧light tube

116‧‧‧ condenser lens

118‧‧‧Reflector

120‧‧‧digital micromirror element

130‧‧‧ projection lens

132‧‧‧imaging lens group

140‧‧‧ Dimmable Light Bar Element

141‧‧‧ Filter element

141a‧‧‧ convex contour

141b‧‧‧ concave contour

141c‧‧‧Circle contour

142‧‧‧ opening

143‧‧‧ Filter

144‧‧‧ shaded area

L‧‧‧visible light

L1‧‧‧First Light

L2‧‧‧Second Light

W1‧‧‧first dominant wavelength range

W2‧‧‧second dominant wavelength range

Wb‧‧‧Blue light energy band

Wr‧‧‧ red light energy band

A, B‧‧‧ Light Bar Position

AC‧‧‧ cross-section profile

Figures 1A and 1B are schematic diagrams showing the transmittances of the light wavelengths of the respective colors. 2A and 2B are schematic diagrams of a projection system according to two embodiments of the present invention, respectively. FIG. 3 is a schematic diagram illustrating a position of a dimming light barrier element according to another embodiment of the present invention. FIG. 4 is a schematic diagram of a dimming light barrier element in a projection system according to an embodiment of the present invention. FIG. 5 is a schematic diagram of a dimming light barrier element in a projection system according to another embodiment of the present invention.

Claims (10)

A projection system includes: a light source for emitting a first light, the first light having a first main wavelength range and a second main wavelength range; a projection lens disposed on a path of the first light; And a dimming light barrier element disposed between the light source and the projection lens, the dimming light barrier element has an opening and a light shielding area outside the opening, and a filter is arranged in the opening, and part of the The first light is blocked by the light-shielding region, and among the remaining first light passing through the opening, a band corresponding to the first main wavelength range passes through the opening, and the second main wavelength range is blocked by the filter to become A second light, so that the second light has a narrow wavelength range relative to the first light. The projection system according to item 1 of the patent application scope, wherein the light source is used to emit a visible light, and the projection system further comprises a filtering device for filtering the visible light so that the first light in the visible light passes through. The projection system according to item 2 of the patent application scope further includes a light pipe for limiting the first light to the light path leading to the projection lens, wherein the dimming light barrier element is located between the light pipe and the light pipe. Between the projection lenses. The projection system according to item 3 of the scope of patent application, further comprising a digital micromirror element disposed on the optical path of the first light or the second light to the projection lens. The digital micromirror element includes a plurality of micro A reflective mirror surface, wherein the dimming light barrier element is located between the light pipe and the digital micromirror element or between the digital micromirror element and the projection lens, and the projection system further includes at least a condenser lens and a reflective mirror, The condenser lens is disposed between the light pipe and the digital micromirror element, and the reflector is disposed between the condenser lens and the digital micromirror element to reflect the first light or the second light to the For these micro-mirror surfaces, the angle at which the first light or the second light enters the micro-mirror surfaces can be adjusted. The projection system according to item 1 of the scope of patent application, wherein the opening shape of the dimming light barrier element is circular. The projection system according to item 5 of the patent application, wherein the circular opening edge of the dimming light barrier element further has a concave contour. The projection system according to item 1 of the scope of patent application, wherein the light-shielding area surrounds the periphery of the opening, so that the middle part becomes a circular or elliptical light-transmitting area. The projection system according to item 6 or item 7 of the scope of patent application, wherein the dimming light barrier element is composed of a whole piece of filter element, and the light shielding area is formed on the filter element in a shielding manner, Only the opening is left transparent. The projection system according to item 8 of the scope of patent application, wherein the dimming light barrier element is shielded by coating, vapor-depositing, or pasting with an opaque material. The projection system according to item 6 or item 7 of the patent application scope, wherein the filter is embedded in the opening in a mosaic manner.