CN117872668A - Optical system and projection device - Google Patents

Abstract

An embodiment of the present application provides an optical system and a projection apparatus, the optical system including: the light source group can emit light rays of a first color, light rays of a second color and light rays of a third color; a black-and-white liquid crystal panel for modulating and transmitting the first color light, the second color light and the third color light; the light combining piece is used for analyzing polarized light modulated by the black-and-white liquid crystal panel, and reflecting light rays of the first color, light rays of the second color and light rays of the third color to the projection lens after combining the light rays; the light recycling component is arranged between the light combining piece and the light source group, so that partial polarized light transmitted by the light combining piece is recycled to the black-white liquid crystal panel and finally sent into the projection lens. The three-color light source is used, the light combining piece is used for replacing the lower polarizer in the prior art, and the light combining piece is matched with the light recycling component to recycle part of polarized light, so that the loss of the polarized light can be reduced, the power consumption of the light source is dynamically reduced, and the light efficiency utilization rate of the projection device is improved.

Description

Optical system and projection device

Technical Field

The application belongs to the technical field of projection devices, and particularly relates to an optical system and a projection device.

Background

The existing projection device mainly has technical routes such as LCD (Liquid-Crystal Display) and DLP (digital light processing) (Digital Light Processing), wherein LCD projection has the characteristics of low cost, simple implementation scheme and the like, and has higher market share. In the technical index of projection, brightness is critical. However, the light efficiency utilization rate of the LCD is always weak compared with other modes due to the limitation of the dimming mode.

The common LCD projection scheme adopts a white light source and an RGB LCD to realize dimming, RGB color resistance exists in the LCD, and other wavelengths are absorbed by transmitting specific wavelengths, so that color display is realized. The light efficiency loss caused by the absorption of light energy by the color resist itself is caused, so that a scheme of respectively modulating RGB pictures by using 2 or 3 black-and-white LCDs and then synthesizing is presented to reduce the light efficiency loss caused by the absorption of the color LCD light resistance. However, in either a single color LCD or a multi-LCD scheme, polarized light when the LCD performs gray scale modulation is absorbed by the polarizer due to the LCD modulation angle, still resulting in a loss of light efficiency.

Disclosure of Invention

The embodiment of the application provides an optical system and a projection device, which can reduce the loss of polarized light and improve the light efficiency utilization rate of the projection device.

In a first aspect, embodiments of the present application provide an optical system applied to a projection apparatus, where the projection apparatus includes a projection lens, the optical system includes:

the light source group comprises a first light source, a second light source and a third light source, and the first light source, the second light source and the third light source can respectively emit first color light rays, second color light rays and third color light rays;

the black-and-white liquid crystal panel is arranged on the light emitting side of the light source group and is used for modulating and transmitting the first color light rays, the second color light rays and the third color light rays;

the light combining piece is arranged on one side, away from the light source group, of the black-and-white liquid crystal panel, and is used for analyzing polarized light modulated by the black-and-white liquid crystal panel, combining the first color light, the second color light and the third color light and then reflecting the combined light to the projection lens;

the light recycling component is arranged between the light combining piece and the light source group, so that partial polarized light transmitted by the light combining piece is recycled to the black-white liquid crystal panel and finally sent to the projection lens.

Optionally, the light combining element is a reflective polarizer or a polarizing beam splitter.

Optionally, the black-and-white liquid crystal panel is disposed perpendicular to the projection lens, and the light combining element is inclined relative to the black-and-white liquid crystal panel and the projection lens, so as to reflect the light transmitted by the black-and-white liquid crystal panel to the projection lens.

Optionally, the optical system further includes a first polarizer, where the first polarizer is disposed between the light source group and the black-and-white liquid crystal panel, and is used to adjust light of the light source group to a polarization state, and the first polarizer is disposed perpendicular to the black-and-white liquid crystal panel;

the optical system further comprises a first reflecting mirror, wherein the first reflecting mirror is arranged between the first polaroid and the black-and-white liquid crystal panel and is inclined relative to the first polaroid and the black-and-white liquid crystal panel respectively so as to reflect polarized light generated by the first polaroid to the black-and-white liquid crystal panel.

Optionally, the light recycling assembly includes:

the reflecting prism is arranged between the first polaroid and the first reflecting mirror, so that partial polarized light transmitted by the light combining piece is reflected to the first reflecting mirror and the black-and-white liquid crystal panel.

Optionally, the light recycling assembly further comprises:

and the light homogenizing lens is arranged between the reflecting prism and the light combining piece so as to homogenize partial polarized light transmitted by the light combining piece.

Optionally, the light recycling assembly further comprises:

the second reflector is arranged between the light combining piece and the light homogenizing lens and is inclined relative to the light combining piece and the light homogenizing lens respectively so as to reflect part of polarized light transmitted through the light combining piece to the light homogenizing lens;

and the third reflector is arranged between the light homogenizing lens and the second reflector and is opposite to the second reflector so as to reflect partial polarized light reflected by the second reflector to the light homogenizing lens.

Optionally, the light recycling assembly further comprises:

the first wave plate is arranged between the second reflecting mirror and the third reflecting mirror to adjust the polarization state of partial polarized light transmitted by the light combining piece.

Optionally, the optical system further includes:

the second wave plate and the polarization spectroscope are arranged between the light source group and the black-and-white liquid crystal panel to adjust the light of the light source group to a polarization state, and the second wave plate is arranged on one side of the polarization spectroscope, which is close to the light source group; and/or

The reflecting light cone is covered on the light source group to converge the light rays of the light source group to collimated light.

In a second aspect, embodiments of the present application further provide a projection apparatus, including:

an optical system as claimed in any one of the preceding claims;

and the projection lens is used for receiving the light rays emitted by the optical system.

In the optical system and the projection device of the embodiment of the application, through using the three-color light source, and using the light combining piece to replace the setting of the lower polarizer in the prior art, the recycling of partial polarized light can be realized by matching with the light recycling component, the loss of polarized light can be reduced, the power consumption of the light source is dynamically reduced, and the light efficiency utilization rate of the projection device is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained from these drawings without inventive effort to a person skilled in the art.

For a more complete understanding of the present application and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings. Wherein like reference numerals refer to like parts throughout the following description.

Fig. 1 is a schematic structural diagram of a projection apparatus according to an embodiment of the present application.

Fig. 2 is a schematic diagram of a first structure of an optical system according to an embodiment of the present application.

Fig. 3 is a schematic diagram of a second structure of an optical system according to an embodiment of the present application.

Fig. 4 is a schematic diagram of a third structure of an optical system according to an embodiment of the present application.

Fig. 5 is a schematic diagram of a fourth structure of an optical system according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a projection apparatus according to an embodiment of the present application. The embodiment of the application provides a projection device 1, where the projection device 1 may be a projector, or called a projector, and is a device that can project an image or video onto a curtain. The projection device 1 may also be a Head Up Display (HUD) system in an automobile, or referred to as a Head Up Display system, which means a blind operation, multifunctional dashboard centered on the vehicle driver. The head-up display system is used for projecting important driving information such as speed per hour and navigation onto a windshield in front of a driver, so that the driver can see the important driving information such as speed per hour and navigation without lowering the head and turning the head as much as possible.

The existing projection device mainly has technical routes such as LCD, DLP and the like, wherein the LCD projection has the characteristics of low cost, simple implementation scheme and the like, and the market share is higher. In the technical index of projection, brightness is critical. However, the light efficiency utilization rate of the LCD is always weak compared with other modes due to the limitation of the dimming mode.

The common LCD projection scheme adopts a white light source and an RGB LCD to realize dimming, RGB color resistance exists in the LCD, and other wavelengths are absorbed by transmitting specific wavelengths, so that color display is realized. The light efficiency loss caused by the absorption of light energy by the color resist itself is caused, so that a scheme of respectively modulating RGB pictures by using 2 or 3 black-and-white LCDs and then synthesizing is presented to reduce the light efficiency loss caused by the absorption of the color LCD light resistance. However, in either a single color LCD or a multi-LCD scheme, in gray-scale modulation, it is often necessary to absorb polarized light after the LCD modulation angle by using a lower polarizer close to the projection lens, so that gray-scale display of each pixel is achieved, and in most of projection scenes, the gray scale of the picture is not in the maximum state, so that in most of the time, the lower polarizer absorbs polarized light according to the requirement of the gray scale of the picture, that is, the polarized light is absorbed by the polarizer due to the LCD modulation angle during the gray-scale modulation of the LCD, which still results in light efficiency loss.

In order to reduce the above-described problems, the present embodiment improves the optical system in the projection apparatus 1, and will be described below with reference to the accompanying drawings.

The optical system 100 may be applied to the projection apparatus 1, but the optical system 100 is not limited to be applied to the projection apparatus 1, for example, may also be applied to an illumination device or other display device, and the embodiment of the present application is described by taking the application of the optical system 100 to the projection apparatus 1 as an example, and should not be construed as limiting the projection apparatus 1.

The projection device 1 comprises, for example, an optical system 100 and a projection lens 200, the optical system 100 being adapted to provide a modulated light source and to input it into the projection lens 200. The projection lens 200 is the last link of the whole light path, and determines the core parameters of the projection device 1, such as the color, brightness, focusing definition, etc., that is, the device for projecting the picture onto the curtain.

It should be noted that, the projection lens 200 may also be an integral part of the optical system 100, where the projection lens 200 is distinguished from the optical system 100 for convenience of description, and should not be construed as limiting the projection lens 200 and the optical system 100.

For example, please refer to fig. 1 in combination with fig. 2, fig. 2 is a schematic diagram of a first structure of an optical system according to an embodiment of the present application. The optical system 100 includes a light source group 110, a black-and-white liquid crystal panel 120, a light combining member 130, and a light recycling assembly 140.

The light source group 110 is used for providing a projection light source for the optical system 100, and can be matched with the black-and-white liquid crystal panel 120 to realize the display of pictures. Illustratively, the light source group 110 includes a first light source 112, a second light source 114, and a third light source 116, where the first light source 112, the second light source 114, and the third light source 116 are capable of emitting a first color light, a second color light, and a third color light, respectively. The first, second and third color lights are three primary colors, i.e., red, green, blue, or RGB, which form a picture. The first color light, the second color light and the third color light can be mixed to generate different gray scales, so that different display effects are displayed.

The black-and-white liquid crystal panel 120 is disposed on the light emitting side of the light source set 110, and the black-and-white liquid crystal panel 120 is used for modulating and transmitting the first color light, the second color light and the third color light.

The black-and-white liquid crystal panel generally uses TN (Twist Nematic) twisted nematic liquid crystal, and the working principle of the black-and-white liquid crystal panel is as follows: the nematic liquid crystal is sandwiched between two glass sheets, the surface of which is coated with a transparent conductive film ITO (indium tin oxide) for electrodes, and then an alignment layer PI (polyimide) is coated on the glass with the film electrodes so that the liquid crystal is aligned in a specific direction parallel to the glass surface. The natural state of the liquid crystal has a twist of 90 degrees, the liquid crystal molecules can be rotated by an electric field, the birefringence of the liquid crystal changes with the direction of the liquid crystal, and the polarization direction of the polarized light is rotated after passing through the TN type liquid crystal as a result. As long as the appropriate thickness is chosen to change the polarization direction of the polarized light by just 90 degrees, two parallel polarizers can be used to make the light completely non-passing. The liquid crystal direction is parallel to the electric field direction by a voltage large enough so that the polarization direction of the light is not changed and the light can pass through the second polarizer. Thus, the brightness of the light can be controlled.

In addition, the black-and-white liquid crystal panel 120 according to the embodiment of the present application is different from the common color liquid crystal panel in that the black-and-white liquid crystal panel 120 eliminates the setting of the color filter, so that the problem of light efficiency reduction caused by the absorption of light by the color filter can be reduced. Also, it is necessary to implement a projection light path in cooperation with the light source group 110 capable of emitting light rays of the first color, light rays of the second color, and light rays of the third color.

The light combining element 130 is disposed at a side of the black-and-white liquid crystal panel 120 facing away from the light source set 110, and the light combining element 130 is configured to analyze the polarized light modulated by the black-and-white liquid crystal panel 120, and combine the first color light, the second color light, and the third color light, and reflect the combined light to the projection lens 200.

It should be noted that, the light combining element 130 not only acts as a lower polarizer in the prior art, but also analyzes the polarized light modulated by the black-white liquid crystal panel 120; the light combining member 130 is used as a device for combining the light of the first color, the light of the second color and the light of the third color, so that the device arrangement can be saved, and the cost can be reduced.

In order to reduce the occurrence of such problems, the embodiment of the present application uses the light combining element 130 to replace the lower polarizer in the prior art, and the light combining element 130 can also transmit part of the polarized light, so as to facilitate recycling.

The light recycling component 140 is disposed between the light combining member 130 and the light source group 110, so as to recycle part of the polarized light transmitted by the light combining member 130 to the black-white liquid crystal panel 120, and finally send the polarized light into the projection lens 200, thereby recycling the polarized light and improving the light efficiency utilization rate.

In the optical system 100 provided in this embodiment of the present application, by using the three-color light source and using the light combining member 130 to replace the lower polarizer in the prior art, the light recycling component 140 is matched with the light recycling component to recycle part of polarized light, so that the loss of polarized light can be reduced, the power consumption of the light source can be dynamically reduced, and the light efficiency utilization rate of the projection device 1 can be improved.

The light combining member 130 is a reflective polarizer or a polarizing beam splitter, for example. Reflective polarizers, alternatively referred to as reflective polarizers, transmit the desired polarization and reflect the remaining polarization, e.g., p-polarized light is not reflected, but is transmitted, while s-polarized light is reflected. The polarization spectroscope can divide the incident unpolarized light into two perpendicular linearly polarized light beams, wherein p polarized light completely passes through, s light is reflected at an angle of 45 degrees, the emergent direction forms an angle of 90 degrees with the p light, the p polarized light and the s polarized light are both linearly polarized light, and the polarization directions are mutually perpendicular. By utilizing this characteristic, the first color polarized light, the second color polarized light and the third color polarized light required by the combined light can be reflected to the projection lens 200, while the other part of polarized light is transmitted through the light combining member 130 and recycled by the light recycling component 140, so that the polarized light of the transmitted part can not be wasted.

For example, the black-and-white liquid crystal panel 120 is disposed perpendicular to the projection lens 200, and the light combining element 130 is inclined with respect to the black-and-white liquid crystal panel 120 and the projection lens 200, for example, an inclination angle may be 45 ° to match with the transmitted polarized light and the reflected polarized light of the light combining element 130, so that the light transmitted by the black-and-white liquid crystal panel 120 can be reflected to the projection lens 200, and the transmitted polarized light can be recycled.

The optical system 100 further includes a first polarizer 150, where the first polarizer 150 is disposed between the light source group 110 and the black-and-white liquid crystal panel 120, and the first polarizer 150 is used for adjusting the light of the light source group 110 to a polarization state. The first polarizer 150, that is, the upper polarizer in the prior art, is used for converting the light beam generated by the backlight source into polarized light, and the lower polarizer in the prior art is used for analyzing the polarized light after being electrically modulated by the liquid crystal to generate a contrast, thereby generating a display picture. The first polarizer 150 is disposed perpendicular to the black-and-white liquid crystal panel 120, so as to reduce the space occupied by the optical system 100.

Since the light source group 110 is disposed vertically with respect to the black-and-white liquid crystal panel 120, it is necessary to provide a mirror to change the optical path in order to achieve that the light of the light source group 110 is incident on the black-and-white liquid crystal panel 120.

The optical system 100 further includes a first reflecting mirror 160, where the first reflecting mirror 160 is disposed between the first polarizer 150 and the black-and-white liquid crystal panel 120 and is inclined with respect to the first polarizer 150 and the black-and-white liquid crystal panel 120, respectively, so as to reflect the polarized light generated by the first polarizer 150 to the black-and-white liquid crystal panel 120. It will be appreciated that the light emitted by the light source group 110 is in a horizontal direction, and the black-and-white liquid crystal panel 120 is also disposed along the horizontal direction, so that the first reflecting mirror 160 may be disposed at an angle of 45 ° with respect to the light source group 110 and the black-and-white liquid crystal panel 120, respectively, so that the light of the first color, the light of the second color, and the light of the third color in the horizontal direction may be converted into the light of the vertical direction by the first reflecting mirror 160 to enter the black-and-white liquid crystal panel 120.

The structural composition of the light recovery assembly 140 will be described below.

For example, please refer to fig. 3 in conjunction with fig. 1 and fig. 2, fig. 3 is a schematic diagram of a second structure of an optical system according to an embodiment of the present application. The light recycling assembly 140 includes a reflecting prism 141, a light homogenizing lens 142, a second reflecting mirror 143, and a third reflecting mirror 144.

The reflective prism 141 is disposed between the first polarizer 150 and the first mirror 160 to reflect the partially polarized light transmitted by the light combining member 130 to the first mirror 160 and the black-and-white liquid crystal panel 120. Illustratively, the reflecting prism 141 is a triangle such as an isosceles right triangle, and the hypotenuse of the reflecting prism 141 is disposed toward the light source group 110 so that a portion of the vertically polarized light transmitted by the light combining member 130 may be reflected to the first reflecting mirror 160.

The integrator 142 is disposed between the reflecting prism 141 and the light combining member 130 to uniformly combine the partially polarized light transmitted by the light combining member 130. Since the RGB gray scales of the screen are not uniformly distributed, the intensity distribution of the polarized light transmitted from the light combining member 130 is not uniform, and therefore, before entering the reflecting prism 141, the light source is uniformly distributed by adding the light homogenizing lens 142, so as to reduce the influence on the screen caused by the non-uniformity phenomenon of the recovered light. Illustratively, the integrator lens 142 may also be referred to as a fly-eye lens, which is formed by a series of small lens combinations, and the application of a double-row fly-eye lens array to the illumination system can achieve high light energy utilization and uniform illumination over a large area. The fly-eye lens has wide application prospect in the field of micro-displays and projection displays.

It should be noted that, the light transmitted from the light combining member 130 is vertically downward, and the light entering the light homogenizing lens 142 and the reflecting prism 141 is vertically upward, and thus, an optical device is also required to change the light path.

The second mirror 143 and the third mirror 144 are also used to change the light path. The second reflecting mirror 143 is disposed between the light combining member 130 and the light homogenizing lens 142, and is inclined with respect to the light combining member 130 and the light homogenizing lens 142, respectively, and may be inclined at an angle of 45 ° to reflect a portion of the polarized light transmitted through the light combining member 130 to the light homogenizing lens 142. After that, the third mirror 144 is disposed between the light homogenizing mirror 142 and the second mirror 143, and is disposed opposite to the second mirror 143 to reflect the partially polarized light reflected by the second mirror 143 to the light homogenizing mirror 142. Thus, the second mirror 143 and the third mirror 144 cooperate to effect a change in the optical path.

In the optical system 100 provided in this embodiment of the present application, by using the three-color light source and using the light combining member 130 to replace the lower polarizer in the prior art, the light recycling component 140 is matched with the light recycling component to recycle part of polarized light, so that the loss of polarized light can be reduced, the power consumption of the light source can be dynamically reduced, and the light efficiency utilization rate of the projection device 1 can be improved.

For conventional LCD systems, the scheme of the optical system 100 described above may be used, while for some non-conventional LCD systems, such as black and white liquid crystal panel 120, two polarizers on either side may be parallel, and a half wave plate may be added to the light path to adjust the polarization state of the light.

For example, please refer to fig. 1 to 3 in combination with fig. 4, fig. 4 is a schematic diagram of a third structure of an optical system according to an embodiment of the present application. The light recycling assembly 140 further includes a first wave plate 145, where the first wave plate 145 is disposed between the second reflector 143 and the third reflector 144 to adjust the polarization state of the partial polarized light transmitted by the light combining member 130, so as to meet the use requirement.

The wave plate, also called phase retarder, is made of birefringent material, and it produces a phase shift of two mutually orthogonal polarization components passing through the wave plate, and can be used to adjust the polarization state of the light beam. The quarter wave plate is a wafer with a crystal thickness which can ensure that the optical path difference of o light and e light is lambda/4. The wave plate is rotated to enable the included angle between the polarization direction of the incident light and two axes of the wave plate to be 45 degrees, and the elliptical/circularly polarized light is changed into linearly polarized light after passing through the quarter wave plate. Similarly, if the included angle between the polarization direction of the incident light and the two axes of the wave plate is 45 degrees, the linearly polarized light is changed into circularly polarized light after passing through the quarter wave plate. The half wave plate is a wafer with a crystal thickness such that the optical path difference between o-light and e-light is exactly lambda/2. The linearly polarized light passes through the lambda/2 wave plate and then is linearly polarized light, but the vibration direction is rotated by 2 theta angle with the original direction. The circularly polarized light passes through the lambda/2 wave plate and then is circularly polarized light, but the rotation direction is opposite to the original rotation direction.

The first wave plate 145 in the embodiment of the present application is a half wave plate, and the vibration direction or the rotation direction can be changed so that it meets the use requirement.

It should be noted that, in the above-mentioned scheme, when the light emitted from the first polarizer 150 passes through the surface of the reflecting prism 141, reflection is easily caused, which may affect the original light source efficiency. Embodiments of the present application also improve upon this in order to reduce the impact on the efficiency of the original light source.

For example, please refer to fig. 1 to 4 in combination with fig. 5, fig. 5 is a schematic diagram of a fourth structure of an optical system according to an embodiment of the present application. The optical system 100 further includes a second wave plate 170 and a polarizing beamsplitter 180. The second wave plate 170 and the polarizing beam splitter 180 are disposed between the light source set 110 and the black-and-white liquid crystal panel 120 to adjust the light of the light source set 110 to the polarization state. The second wave plate 170 is disposed on a side of the polarization beam splitter 180 near the light source unit 110. The second wave plate 170 in the embodiment of the present application is a quarter wave plate, and may change the polarization state of the light source group 110. The polarizing beamsplitter 180 is capable of separating incident unpolarized light into perpendicular linearly polarized light. The p polarized light completely passes through, the s polarized light is reflected at an angle of 45 degrees, the emergent direction forms an angle of 90 degrees with the p light, the p polarized light and the s polarized light are linearly polarized light, and the polarization directions are mutually perpendicular. If the polarization direction of the incident light is parallel to the incident plane, the combined beam splitter 180 and the second wave plate 170 can transmit all the light through the beam splitter, and the reflection component is 0. The light enters the measured surface through the second wave plate 170, and passes through the second wave plate 170 again when returning, and the polarization direction of the light can be rotated by pi/2 through twice passing through the second wave plate 170, namely, the light beam is perpendicular to the incident surface, and is totally reflected after passing through the light splitting device, the transmission component is 0, and no energy loss exists. According to the above characteristics, the embodiment combines the polarizing beam splitter 180 with the second wave plate 170, that is, the quarter wave plate, and the polarizing beam splitter 180 is parallel to the first reflecting mirror 160 and inclined at 45 ° with respect to the second wave plate 170, so that the light of the light source group 110 can completely penetrate through the second wave plate 170 and the polarizing beam splitter 180, and the loss of the initial light source is reduced.

Illustratively, in order to reduce the loss of diffuse light from the light source set 110, the optical system 100 of the embodiment of the present application further includes a reflective light cone 190, where the reflective light cone 190 covers the light source set 110 to converge the light of the light source set 110 into collimated light. It will be appreciated that the light emitted by the light source 110 is typically divergent light, and if the light is directly emitted, most of the divergent light is easily lost, so the reflective light cone 190 is provided in the embodiment of the present application to improve this situation. Of course, the collimation of the light is not limited to the reflection cone, and a collimation lens may be used to make the light incident in parallel.

In the above case, the optical path principle or optical path procedure of the optical system 100 is: the light emitted by the light source group 110 is in a natural polarization state, the light is collimated by adopting the reflection light cone 190, the collimated natural light is still in the natural polarization state after passing through the second wave plate 170, linear polarized light is formed after passing through the polarization spectroscope 180, the polarized light emitted by the polarization spectroscope 180 enters the first reflecting mirror 160, and is emitted to the light combining piece 130 after being modulated by the black-and-white liquid crystal panel 120, the light reflected by the light combining piece 130 enters the projection lens 200, the transmitted light has the same polarization state as the polarization spectroscope 180, the partial light is rotated by 90 degrees after passing through the first wave plate 145, reflected by the second reflecting mirror 143 and the third reflecting mirror 144, and is incident into the polarization spectroscope 180 after being homogenized by the light homogenizing mirror 142, reflected by the polarization spectroscope 180 and enters the reflection light cone 190, and is reflected by the reflection light cone 190 back to the polarization spectroscope 180, and the polarized light passes through the second wave plate 170 twice in the process of reflecting the reflection light cone 190 after entering the reflection light cone 190, the polarization angle of which is rotated by 90 degrees, and the emergent light can directly enter the black-and-white liquid crystal panel 120 to be utilized.

It should be noted that, in the above design of the optical system 100 in the projection apparatus 1, the whole system needs to cooperate with a picture recognition algorithm and a brightness adjustment mechanism, so that the color effect is not affected while the light effect is improved.

For example, the image recognition algorithm needs to calculate the transmitted light distribution and the available light efficiency of the light combining element 130 according to the RGB gray scale and the light path characteristics of each area of the image. In general, the light recycling efficiency of an RGB image is different in different gray scales, and the distribution of the gray scales may also affect the distribution of the recycling light sources: if the recovery rate of the picture center is higher, the recovery efficiency of the picture edge is lower. The algorithm obtains the proportion of recoverable light energy of each region according to the characteristics of an optical-mechanical system, theoretical calculation and actual collection, and adds the proportion into the algorithm for operation; the image recognition algorithm can be directly operated on the processor platform of the projection device 1, or a separate module such as an FPGA chip can be added at the display interface, the image is recognized by using the separate module, and the specific gravity of the recyclable light source is similarly calculated by operating the algorithm, so that the light source is dynamically modulated. In addition, the light source adopting the scheme needs to adopt RGB light sources, and the respective brightness of the RGB light sources is adjusted according to the respective gray scales of RGB.

In the optical system 100 and the projection device 1 provided in this embodiment of the present application, by using the three-color light source, and using the light combining member 130 to replace the setting of the lower polarizer in the prior art, the light recycling component 140 is matched with the light recycling component to recycle part of polarized light, so that the loss of polarized light can be reduced, the power consumption of the light source can be dynamically reduced, and the light efficiency utilization rate of the projection device 1 can be improved. In addition, the second wave plate 170 and the polarization beam splitter 180 are matched at the position of the light source group 110, so that reflection loss of an original light source can be reduced, and the light source utilization rate can be further improved.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

In the description of the present application, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more features.

The foregoing has described in detail the optical system and the projection device provided by the embodiments of the present application, and specific examples have been applied herein to illustrate the principles and embodiments of the present application, where the foregoing examples are provided to assist in understanding the methods and core ideas of the present application; meanwhile, as those skilled in the art will vary in the specific embodiments and application scope according to the ideas of the present application, the contents of the present specification should not be construed as limiting the present application in summary.

Claims (10)

1. An optical system for use in a projection device, the projection device including a projection lens, the optical system comprising:

the light source group comprises a first light source, a second light source and a third light source, and the first light source, the second light source and the third light source can respectively emit first color light rays, second color light rays and third color light rays;

the black-and-white liquid crystal panel is arranged on the light emitting side of the light source group and is used for modulating and transmitting the first color light rays, the second color light rays and the third color light rays;

the light combining piece is arranged on one side, away from the light source group, of the black-and-white liquid crystal panel, and is used for analyzing polarized light modulated by the black-and-white liquid crystal panel, combining the first color light, the second color light and the third color light and then reflecting the combined light to the projection lens;

the light recycling component is arranged between the light combining piece and the light source group, so that partial polarized light transmitted by the light combining piece is recycled to the black-white liquid crystal panel and finally sent to the projection lens.

2. The optical system of claim 1, wherein the light combining element is a reflective polarizer or a polarizing beamsplitter.

3. The optical system of claim 2, wherein the black-and-white liquid crystal panel is disposed perpendicular to the projection lens, and the light combining member is inclined with respect to the black-and-white liquid crystal panel and the projection lens, respectively, so as to reflect the light transmitted by the black-and-white liquid crystal panel to the projection lens.

4. The optical system of claim 2, further comprising a first polarizer disposed between the light source group and the black-and-white liquid crystal panel for adjusting light of the light source group to a polarization state, the first polarizer being disposed perpendicular to the black-and-white liquid crystal panel;

the optical system further comprises a first reflecting mirror, wherein the first reflecting mirror is arranged between the first polaroid and the black-and-white liquid crystal panel and is inclined relative to the first polaroid and the black-and-white liquid crystal panel respectively so as to reflect polarized light generated by the first polaroid to the black-and-white liquid crystal panel.

5. The optical system of claim 4, wherein the light recycling assembly comprises:

the reflecting prism is arranged between the first polaroid and the first reflecting mirror, so that partial polarized light transmitted by the light combining piece is reflected to the first reflecting mirror and the black-and-white liquid crystal panel.

6. The optical system of claim 5, wherein the light recycling assembly further comprises:

and the light homogenizing lens is arranged between the reflecting prism and the light combining piece so as to homogenize partial polarized light transmitted by the light combining piece.

7. The optical system of claim 6, wherein the light recycling assembly further comprises:

the second reflector is arranged between the light combining piece and the light homogenizing lens and is inclined relative to the light combining piece and the light homogenizing lens respectively so as to reflect part of polarized light transmitted through the light combining piece to the light homogenizing lens;

and the third reflector is arranged between the light homogenizing lens and the second reflector and is opposite to the second reflector so as to reflect partial polarized light reflected by the second reflector to the light homogenizing lens.

8. The optical system of claim 7, wherein the light recycling assembly further comprises:

the first wave plate is arranged between the second reflecting mirror and the third reflecting mirror to adjust the polarization state of partial polarized light transmitted by the light combining piece.

9. The optical system of claim 2, wherein the optical system further comprises:

the second wave plate and the polarization spectroscope are arranged between the light source group and the black-and-white liquid crystal panel to adjust the light of the light source group to a polarization state, and the second wave plate is arranged on one side of the polarization spectroscope, which is close to the light source group; and/or

The reflecting light cone is covered on the light source group to converge the light rays of the light source group to collimated light.

10. A projection apparatus, comprising:

the optical system of any one of claims 1-9;

and the projection lens is used for receiving the light rays emitted by the optical system.