Projection optical module and projection equipment

Abstract

The invention relates to a projection optical module and projection equipment. The projection optical module comprises a light source; the light source is arranged on the light inlet face, the light cone comprises a light inlet face, a light outlet face opposite to the light inlet face and a side face connecting the light inlet face and the light outlet face, and the light source is arranged on the light inlet face and comprises a plurality of light-emitting chips arranged on the light inlet face in an array mode; the orthographic projection of the light cone on a first virtual plane is an isosceles trapezoid, the first virtual plane is perpendicular to the light incident surface, the isosceles trapezoid comprises a first edge, a second edge and a bevel edge which are arranged in parallel, the first edge is parallel to the second edge, on the first edge, a normalized spectrum of secondary reflection of the light source meets a preset condition, and on the second edge, a normalized spectrum of secondary reflection of the light source meets a preset condition. Therefore, the color uniformity of the projection optical module is improved, and the display effect of the projection equipment is improved.

Description

Technical Field

[0001] The present invention relates to the field of projection technology, and in particular to a projection optical module and a projection device. Background Art

[0002] A single-chip LCD projection device is a projection product that uses a transmissive LCD panel to modulate the light emitted by an optical module to form an image, and then uses a projection lens to magnify the image and project it onto the projection area. Compared to projection devices based on other principles, such as DLP (Digital Light Processing) or LCoS (Liquid Crystal On Silion), single-chip LCD projection devices are inexpensive and easy to make.

[0003] An optical module in the related art uses a light cone to diffuse the light emitted by a light source. However, as the position of the light point and the light angle are different, the optical path of the light in the light cone is also different. The absorption coefficient of the medium for different wavelengths is different. Therefore, the color coordinates of the same spectrum will be different after passing through different optical paths, that is, the color is uneven. This is not conducive to improving the color uniformity of the optical module, and further not conducive to improving the display effect of the projection device. Summary of the invention

[0004] Based on this, the present application proposes a projection optical module and a projection device, so as to improve the color uniformity of the projection optical module, and further improve the display effect of the projection device.

[0005] An embodiment of the first aspect of the present application proposes a projection optical module, including: a light source; and a light cone, the light cone including a light incident surface, a light exit surface opposite to the light incident surface, and a side surface connecting the light incident surface and the light exit surface, the light source is arranged on the light incident surface, and the light source includes a plurality of light-emitting chips arranged in an array on the light incident surface; the orthographic projection of the light cone on a first virtual plane is a polygon, the first virtual plane is perpendicular to the light incident surface, the polygon includes a first side and a second side arranged in parallel, the first side is the orthographic projection of the light incident surface on the first virtual plane, and the second side is the orthographic projection of the light exit surface on the first virtual plane; on the first side, the normalized spectrum of the secondary reflection of the light emitted by the light source Satisfies the following formula:

[0006] ;

[0007] Where λ is the wavelength of visible light from the light source, d is the length of the second side, h is the distance between any point on the first side and the lower edge of the first side, is the function of the spectrum of the light emitted by the light source after secondary reflection with respect to λ and h, is the normalized spectrum of visible light at the midpoint of the second side as a function of λ.

[0008] In some embodiments, the polygon is an isosceles trapezoid, and the orthographic projection of the side surface on the first virtual plane is the hypotenuse of the isosceles trapezoid;

[0009] Satisfies the following formula:

[0010] ;

[0011] Wherein, A is the length of the first side, α is the angle between the extension lines of the two hypotenuses, θ is the angle between the incident light after secondary reflection in the light cone and the light incident surface, X1 is the incident angle of the incident light after secondary reflection in the light cone when it is reflected on the side for the first time, and X2 is the incident angle of the incident light after secondary reflection in the light cone when it is reflected on the side for the second time. is the reflectivity of the light cone reflection surface as a function of λ and the incident angle X, is the spectrum of the incident light on the light entrance surface as a function of λ and h.

[0012] In some embodiments, X1, X2 and θ satisfy the following formula:

[0013] ;

[0014] ;

[0015] ;

[0016] Wherein, c is the length of the hypotenuse.

[0017] In some embodiments, the light source includes a middle region and a peripheral region surrounding the middle region, wherein the spectral intensity of the middle region is and the spectral intensity of the surrounding area satisfy:

[0018] ;

[0019] ;

[0020] Spectrum in the center of the picture Approximately meets:

[0021] ;

[0022] in, is the normalized spectrum at the center of the light source, is the reflectivity of the side surface of the light cone, is the visible light spectrum at the edge of the second side as a function of λ.

[0023] In some embodiments, the deviation of the blue peak wavelength, the green peak wavelength, and the red peak wavelength of the spectrum of the peripheral region from the spectrum of the middle region is within 10 nm.

[0024] In some embodiments, the light incident surface includes a central area and an edge area surrounding the central area, the projection of the middle area on the light incident surface coincides with the central area, and the projection of the peripheral area on the light incident surface coincides with the edge area; the first edge includes a first segment and two second segments symmetrical about the first segment, the first segment is an orthographic projection of the central area on the first virtual plane, the second segment is an orthographic projection of the edge area on the first virtual plane, and the total length P of the two second segments and the length Y of the first segment satisfy: 1 / 3Y≤P≤2Y.

[0025] In some embodiments, the central area has a first center, the orthographic projection of the first center on the first virtual plane is the midpoint of the first segment, and the blue light peak intensity of the light source located in the edge area is 101.2% to 109.3% of the blue light peak intensity of the light source located in the first center;

[0026] And / or, the peak intensity of green light of the light source located in the edge region is 89.3% to 99.7% of the peak intensity of green light of the light source located in the first center.

[0027] In some embodiments, the shape of the light emitting surface and the light incident surface is one of a square and a rectangle.

[0028] In some embodiments, the projection optical module further includes an LCD panel disposed on a side of the light cone away from the light source, and a collimating lens disposed between the LCD panel and the light cone.

[0029] An embodiment of a second aspect of the present application provides a projection device, comprising the projection optical module of the first aspect.

[0030] Since the edge of the picture is the spectrum formed by the secondary reflection of the light emitted from the light incident surface of the light cone, the secondary reflection spectrum is the main reason for the uneven display of the picture. Therefore, the present application defines the spectrum of the secondary reflected light at the edge of the light exiting surface of the light cone through a formula, and keeps it the same as the spectrum of the light at the center of the light exiting surface of the light cone, thereby improving the problem of uneven color of the picture and improving the display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic structural diagram of a light cone optical module in the related art;

[0032] FIG2 is a schematic diagram of a light path of light propagating in a light cone in the related art;

[0033] Figure 3 This is a schematic diagram of the structure of a projection optical module according to an embodiment of the present application;

[0034] Figure 4 for Figure 3 A schematic structural diagram of the projection of a light cone of the projection optical module onto a first virtual plane;

[0035] Figure 5 for Figure 3 Another structural schematic diagram of the projection of the light cone of the projection optical module on the first virtual plane is shown.

[0036] The reference numerals are as follows:

[0037] 1-light cone optical module; 2-light source; 3-light cone; 31-light incident surface; 32-upper surface; 33-lower surface; 34-optical axis; 4-collimating lens; 5-LCD panel; G-light emitting point;

[0038] 100-projection optical module; 110-light source; 120-light cone; 121-light incident surface; 1211-first side; 1211a-first section; 1211b-second section; 122-light exit surface; 1221-second side; 123-side; 1231-hypotenuse;

[0039] 130 - LCD panel; 140 - collimating lens; S1 - first virtual plane. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0043] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0045] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0046] FIG1 is a schematic diagram of the structure of a light cone optical module in the related art, and FIG2 is a schematic diagram of the optical path of light propagating in the light cone. As shown in FIG1, the light cone optical module 1 includes a light source 2 and a light cone 3, a collimating lens 4 and an LCD panel 5 sequentially arranged on the light output side of the light source 2. The light source 2 is arranged on the light incident surface 31 of the light cone 3. It is assumed that the light incident surface of the light cone 3 has a light-emitting point G. As shown in FIG2, the positive projection figure of the light cone 3 on a certain plane is an isosceles trapezoid. Combining FIG1 and FIG2, it can be seen that the reflection of the light emitted from point A on the upper surface 32 and the lower surface 33 in the light cone 3 can be simplified as the reflection of the light emitted from point A on the two waist lines of the isosceles trapezoid. Considering the light energy loss caused by multiple reflections, in the general light cone scheme, the light is reflected at most twice. Then, the light emitted from point A can be divided into three angle intervals according to the number of reflections. As shown in FIG2, the first angle interval is, and the angle range with the optical axis 34 is 0 to θ1. The light in this angle interval does not pass through the reflection surface of the light cone 3 and is directly emitted. The second angle interval is that the angle range with the optical axis 31 is θ1 to θ2, and the light in this angle interval is emitted after a single reflection of the light cone 3. The third angle interval is that the angle range with the optical axis 34 is θ2 to 90°, and the light in this angle interval is emitted after a double reflection of the light cone 3. As can be seen from FIG. 2, according to the symmetry relationship, the light received on the LCD panel 5 is composed of the light emitted in 2 first angle intervals, 2 second angle intervals, and 2 third angle intervals. Among them, the light emitted in the first angle interval and the second angle interval fills the entire LCD panel 5, while the light emitted in the third angle interval is only distributed at the edge of the screen.

[0047] In this way, due to the secondary reflected light emitted in the third angle range, the colors of the center and edge of the final picture are uneven, affecting the image effect.

[0048] Based on the above problems, the present application proposes a projection optical module and a projection device, so as to improve the color uniformity of the projection optical module and further improve the display effect of the projection device.

[0049] The embodiment of the first aspect of the present application provides a projection optical module 100. Figure 3 and Figure 4As shown, the projection optical module 100 includes a light source 110 and a light cone 120. The light cone 120 includes a light incident surface 121, a light emitting surface 122 opposite to the light incident surface 121, and a side surface 123 connecting the light incident surface 121 and the light emitting surface 122. The light source 110 is disposed on the light incident surface 121. The light source 110 includes a plurality of light-emitting chips arranged in an array on the light incident surface 121. The orthographic projection of the light cone 120 on the first virtual plane S1 is a polygon, and the first virtual plane S1 is perpendicular to the light incident surface 121. The polygon includes a first side 1211 and a second side 1221 that are arranged in parallel. The first side 1211 is the orthographic projection of the light incident surface 121 on the first virtual plane S1, and the second side 1221 is the orthographic projection of the light emitting surface 122 on the first virtual plane S1. On the first side 1211, the normalized spectrum of the light emitted by the light source 110 after secondary reflection is Satisfies the following formula:

[0050] ;

[0051] Wherein, λ is the wavelength of visible light of the light source 110, d is the length of the second side 1221, h is the distance between any point E of the first side 1211 and the lower edge of the first side 1211, is the function of the spectrum of the light emitted by the light source 110 after secondary reflection with respect to λ and h, is a function of the normalized spectrum of visible light at the midpoint of the second side 1221 with respect to λ.

[0052] In the present application, the projection optical module 100 includes a light source 110 and a light cone 120. The light source 110 is used to provide the projection device with light required to form a projection image. The light source 110 emits white illumination light, wherein the light source 110 can be a white light source that excites fluorescence by laser or LED. Alternatively, the light source 110 can be a monochromatic light source or a combination of light sources of different colors, and the monochromatic light source can use any monochromatic light source of red, green and blue, and the combination of light sources of different colors can use a combination of any monochromatic light sources of red, green and blue. This application does not limit this.

[0053] The light cone 120 refers to an optical device for homogenizing light. In addition, due to the high light collection efficiency of the light cone 120, the brightness of the projection optical module 100 can be improved and its power consumption can be reduced. Optionally, the light cone 120 can be a solid light cone, such as a solid glass cone rod made of glass; or, the light cone 120 can also be a hollow light cone, which is formed by connecting and enclosing a plurality of reflective surfaces in sequence. The light cone 120 has a light incident surface 121 and a light emitting surface 122 that are arranged opposite to each other. The cross-sectional area of ​​the light cone 120 gradually increases along the direction from the light incident surface 121 to the light emitting surface 122, so that the area of ​​the light emitting surface 122 of the light cone 120 is larger than the area of ​​the light incident surface 121. The light source 110 is arranged on the light incident surface 121. In this way, the light emitted by the light source 110 is homogenized by using the light cone 120, thereby forming a divergent surface light. In this way, it is beneficial to improve the uniformity and luminous area of ​​the light. Furthermore, since the light cone 120 has a high light collection efficiency, it is also beneficial to improve the brightness of the projection optical module 100 and thus reduce its power consumption.

[0054] The present application restricts the spectrum of the light source 110. As described in the background art, as shown in FIG. 1 and FIG. 2, the light received on the LCD panel 5 is composed of light emitted in two first angle intervals, two second angle intervals, and two third angle intervals. Among them, the light emitted in the first angle interval and the second angle interval fills the entire LCD panel 5, the light emitted in the third angle interval is only distributed at the edge of the picture, and the light emitted in the third angle interval is secondary reflected in the light cone. The secondary reflected light is the direct cause of the uneven color of the picture. Therefore, as long as the spectrum of the secondary reflected light at the edge of the light emitting surface of the light cone 120 is controlled to be the same as the spectrum of the light at the center of the light emitting surface of the light cone 120, the problem of uneven color of the picture can be greatly improved and the display effect can be improved.

[0055] Specifically, a virtual plane, namely the first virtual plane S1, is first set. Among them, the first virtual plane S1 is perpendicular to the light incident surface 121. Then the orthographic projection figure of the light cone 120 on the first virtual plane S1 is a quadrilateral ABCD. The light source 110 includes a plurality of light-emitting chips arranged in an array on the light incident surface 121, for example, they may be LED chips. The LED chip can be approximately regarded as a Lambertian light source, and it is assumed that the spectrum of the LED chip is I(λ), that is, the light intensity I is a function of the wavelength λ of visible light. Since the orthographic projection shape of the light incident surface 121 is the first edge 1211, there are several rows of LED chips on the first edge 1211. Select any point E on the first edge 1211, and the distance between the point E and the lower edge of the first edge 1211 is h. Then the spectrum of the light emitted from the LED chip at the point E is I(λ, h). Furthermore, after the light from the LED chip at point E is emitted, a portion of it will be reflected twice in the light cone 120. Then, the normalized spectrum of the light emitted from the first edge 1211 after the second reflection is: It can be seen that the normalized spectrum of the secondary reflection is related to the position of point E and the wavelength of the light. Further, after the light of the LED chip at point E is emitted, the normalized spectrum of the light emitted from the center of the light cone 120 without reflection is Then, when When , it indicates that the normalized spectrum of the light emitted from the edge of the light emitting surface 122 is the same as the normalized spectrum emitted from the center. This is helpful to improve the problem of uneven color of the picture and improve the display effect.

[0056] It should be noted that in the above formula, the normalized spectrum of the light emitted from the center of the light exit surface 122 of the light cone 120 is It can be obtained through a spectrum tester. Then, according to the known The spectral curve and the above equation are used to obtain the normalized spectrum of secondary reflection. The normalized spectrum of secondary reflection is related to the position of point E and the wavelength of light, so the spectrum I (λ, h) of the LED chip at any point on the first side 1211 of the light incident surface 121 can be reversely adjusted according to the normalized spectrum of secondary reflection, thereby obtaining the spectrum of the LED chip at different positions of the light source 110. That is, the present application actually makes differentiated adjustments to the spectrum of light-emitting chips, such as LED chips, at different positions of the light source 110, rather than setting the entire light source 110 to a single spectrum as in the related art, so that the secondary reflection spectrum at the edge of the light exit surface 122 of the light cone 120 is consistent with the central spectrum, thereby achieving the effect of adjusting the uniformity of the picture.

[0057] In some embodiments, the polygon is an isosceles trapezoid, and the orthographic projection of the side surface 123 on the first virtual plane S1 is the hypotenuse 1231 of the isosceles trapezoid. Satisfies the following formula:

[0058] ;

[0059] Wherein, A is the length of the first side 1211, c is the length of the hypotenuse 1231, α is the angle between the extension lines of the two hypotenuses 1231, θ is the critical angle between the incident light that undergoes secondary reflection in the light cone 120 and the light incident surface 121, X1 is the incident angle of the incident light that undergoes secondary reflection in the light cone 120 when it is reflected for the first time at the side surface 123, X2 is the incident angle of the incident light that undergoes secondary reflection in the light cone 120 when it is reflected for the second time at the side surface 123, is the reflectivity of the reflecting surface of the light cone 120 as a function of λ and the incident angle X, is a function of the spectrum of the incident light on the light entrance surface 121 of the light cone 120 with respect to λ and h.

[0060] This embodiment further defines the functional relationship between the secondary reflection spectrum of the incident light on the light incident surface 121 of the light cone 120 and the spectrum of the incident light. Specifically, select any point E on the first side 1211, and the distance between the point E and the lower edge of the first side 1211 is h. Then the spectrum of the light from the LED chip at the point E after emission is . Then the spectrum of the light after the first reflection is The spectrum of the light after the second reflection is By integrating the above, we can get the spectrum of all secondary reflected light emitted from point E: At this time, h is integrated again on AB to obtain the spectrum of the light emitted from all points on the first side 1211 after secondary reflection: The spectral function is related to λ and h. At this time, the uniformity of the image can be improved by simply normalizing the above spectrum to be the same as the normalized spectrum at the center of the light exit surface 122 of the light cone 120, that is, the midpoint of the second side 1221. The secondary reflection spectrum is related to the spectrum at any point on the first side 1211, so it can be calculated based on The spectrum of the LED chip at any point on the first side 1211 can be inverted by using a function; or the spectrum of the LED chip at any line segment can be inverted by dividing the first side 1211 into multiple line segments. In this way, the peak of one or more rows of LED chips on the first side 1211 can be adjusted so that its spectrum meets the spectrum of the LED chip calculated by inverting. In this way, the spectrum adjustment at different positions of the entire light source 110 is completed.

[0061] It should be noted that in the above process, the spectrum can be obtained by measuring with a spectrum tester. as well as The reflectivity function can be obtained by testing the reflectivity of light of different wavelengths at different angles on the light cone using a reflectivity meter.

[0062] In some embodiments, X1, X2 and θ satisfy the following formula:

[0063] ;

[0064] .

[0065] This embodiment defines the relationship between the incident angle X1 at the first reflection, the incident angle X2 at the second reflection, and the angle θ between the incident light that has undergone secondary reflection in the light cone 120 and the light incident surface 121. Specifically, as shown in the figure, α is the angle between the extension lines of the two hypotenuses 1231, and θ is the critical angle between the incident light that has undergone secondary reflection in the light cone 120 and the light incident surface 121. The critical angle means that when the angle between the light emitted from the light incident surface 121 and the light incident surface 121 is greater than or equal to θ, the light will undergo secondary reflection. Based on the geometric relationship of the triangle and the relationship between the incident angle and the perpendicularity of the normal, the incident angle at the first reflection can be obtained. , the incident angle at the second reflection .

[0066] In some embodiments, θ also satisfies the following formula:

[0067] .

[0068] In this embodiment, the value of θ can be obtained by the above formula. Thus, when the angle between the light emitted from the light incident surface 121 and the light incident surface 121 is greater than or equal to θ, the light will inevitably be reflected twice in the light cone 120. The above formula can be derived from the sine theorem. Figure 4 As shown, the intersection point of the second reflected light ray with the hypotenuse 1231 during the first reflection in the light cone is F. In triangle BEF, the sine theorem yields:

[0069] ;

[0070] In the DCF triangle, the law of sines gives:

[0071] ;

[0072] and That is to say, when A, α, c, and h are known, the critical angle θ at which the light emitted by the LED chip at any point on the light incident surface 121 undergoes secondary reflection can be obtained.

[0073] In some embodiments, Figure 3 and Figure 5 As shown, the light incident surface 121 includes a central area (not shown in the figure) and an edge area surrounding the central area (not shown in the figure), the first edge 1211 includes a first segment 1211a and two second segments 1211b symmetrical about the first segment 1211a, the first segment 1211a is the orthographic projection of the central area on the first virtual plane S1, the second segment 1211b is the orthographic projection of the edge area on the first virtual plane S1, and the total length P of the two second segments 1211b and the length Y of the first segment 1211a satisfy: 1 / 3Y≤P≤2Y.

[0074] In some embodiments, the light incident surface 121 is divided into a central area and an edge area surrounding the central area. In some embodiments, two second sections 1211b symmetrical about the first section 1211a can be set as the positive projection of the edge area on the first virtual plane S1, that is, the edge area is annular with equal width.

[0075] In some embodiments, the width of the orthographic projection of a single edge region on the first virtual plane S1 is one-fourth of the width of the central region, and the total length of the orthographic projections of the two edge regions on the first virtual plane S1, that is, the total length of the two second sections 1211b, is one-half of the length of the first section 1211a. In this way, the first side 1211 can be divided into three parts, and when setting the spectrum of the LED chip, the spectrum of the two second sections 1211b can be set to be the same, and the spectrum of the first section 1211a is different from the spectrum of the second section 1211b, so that the convenience of arranging the light source 110 can be improved while adjusting the uniformity of the picture.

[0076] In some embodiments, the central area has a first center, the orthographic projection of the first center on the first virtual plane S1 is the midpoint M of the first segment 1211a, the blue light peak intensity of the light source 110 located in the edge area is 101.2% to 109.3% of the blue light peak intensity of the light source 110 located in the first center, and the green light peak intensity of the light source 110 located in the edge area is 89.3% to 99.7% of the green light peak intensity of the light source 110 located in the first center.

[0077] In this embodiment, according to the above formula, the spectrum of the LED chip at the center area, i.e., the midpoint M of the first section 1211a, and the spectrum of the LED chip at the edge area, i.e., the second section 1211b, can be obtained. In this way, the blue light peak intensity of the light source 110 located in the edge area is adjusted to 101.2% to 109.3% of the blue light peak intensity of the light source 110 at the first center, and the green light peak intensity of the light source 110 located in the edge area is adjusted to 89.3% to 99.7% of the green light peak intensity of the light source 110 at the first center, thereby effectively improving the problem of uneven display of the projection optical module 100, and thus helping to improve the display effect.

[0078] In some embodiments, the light source 110 is composed of a plurality of LED chips arranged in an array, such as "10 series and 8 parallels" means that the light source 110 includes 8 groups of LED strings connected in parallel, each group of LED strings is composed of 10 LED chips connected in series, and there are 80 LED chips in this light source 110. If a light source 110 is "m series and n parallel", and the m / 3 area and the n / 3 area around the light source 110 are peripheral areas, and the remaining areas are middle areas, in other words, the light source 110 includes a middle area and a peripheral area surrounding the central area, and it can be understood that when the light cone 120 is set on the light-emitting side of the light source 110, the projection of the middle area on the light incident surface 121 coincides with the central area, and the projection of the peripheral area on the light incident surface 121 coincides with the edge area.

[0079] Then the spectral intensity of the peripheral area and the middle area of ​​the light source 110 satisfies:

[0080] ;

[0081] The visible light spectrum at the edge of the second side 1221 is a function of λ , or the visible light spectrum at the edge of the picture as a function of λ for:

[0082] ;

[0083] The visible light spectrum at the center of the second side 1221, or the center spectrum of the picture Approximately meets:

[0084] ;

[0085] in, is the spectrum of the light source 110, is the reflectivity of the side surface 123 of the light cone 120 .

[0086] The spectral intensity of the light source 110 including the middle area and the peripheral area satisfies the above formula, and the light output of the light source 110 as a whole is relatively uniform and has better light output quality.

[0087] It can be understood that, referring to FIG. 2 , the light in the first angle interval does not pass through the reflection surface of the light cone 3 but is directly emitted. Assuming that the light spectrum is , the light in the second angle interval is emitted after being reflected once by light cone 3. Assuming that the reflectivity of the side surface 123 of the light cone is , then we can conclude that the light spectrum in this interval is , the light in the third angle interval is emitted after secondary reflection of light cone 3, and the spectrum of the light in this interval can be obtained as .

[0088] In this way, the visible light spectrum at the edge of the picture can be obtained as a function of λ satisfy:

[0089] ;

[0090] Spectrum in the center of the picture Approximately meets:

[0091] ;

[0092] Further, according to the peak intensity difference of different wavelengths of light in the peripheral area and the middle area of ​​the light source 110 obtained above, the types of phosphors or LED blue light chips in the peripheral area and the middle area of ​​the light source 110 can be adjusted to make the spectrum around and in the center of the image finally formed by the light in the peripheral area and the middle area of ​​the light source 110 more uniform, so as to avoid excessive color difference between the periphery and the center of the image, and the periphery being redder relative to the center. For example, for the normalized spectrum, the peak intensity of blue light in the peripheral area of ​​the light source 110 is 1.2%-9.3% higher than that in the middle area, and the peak intensity of green light in the peripheral area is 0.3%-10.7% lower than that in the middle area, so that an image with more uniform color can be obtained.

[0093] In some embodiments, when the spectrum of the peripheral area of ​​the light source 110 is inconsistent with the spectrum distribution of the middle area, that is, the peak position of the spectrum of the peripheral area is inconsistent with the spectrum distribution of the middle area, in order to compensate for the reddish color phenomenon caused by metal absorption at the edge of the display screen, the spectrum of the light source 110 can also be adjusted. The m / 3 area and the n / 3 area around the light source 110 are peripheral areas, and the deviation of the blue peak wavelength, green peak wavelength, and red peak wavelength of the spectrum of the peripheral area from the spectrum of the middle area is within 10nm, so as to further improve the overall light uniformity of the light source 110. In some embodiments, the peak position of the blue light spectrum of the peripheral area of ​​the light source 110 is 446-448nm.

[0094] In some embodiments, the shape of the light-emitting surface 122 and the light-entering surface 121 is one of a square or a rectangle. This embodiment defines the shape of the light-emitting surface 122 and the light-entering surface 121 of the light cone 120. The shape of the light-emitting surface 122 and the light-entering surface 121 is set to be a square or a rectangle. On the one hand, the spot shape of the outgoing light diverging through the light cone 120 matches the shape of the display screen, which is conducive to improving the adaptability and versatility of the projection optical module 100. On the other hand, it is also conducive to improving the convenience of arranging the light source 110 on the light-entering surface 121.

[0095] In some embodiments, Figure 3As shown, the projection optical module 100 also includes an LCD panel 130 disposed on the side of the light cone 120 away from the light source. The LCD panel 130 is a "liquid crystal display" and is used to convert the received illumination light into image light. It is usually composed of a polarizer, an array substrate, an opposing substrate, and a liquid crystal material sandwiched between the two. The technology of the LCD panel 130 is mature and the cost is low, which is conducive to reducing the production cost of the projection optical module 100.

[0096] In some embodiments, Figure 3 As shown, the projection optical module 100 also includes a collimating lens 140 disposed between the LCD panel 130 and the light cone 120. The collimating lens 140 refers to a lens structure that collimates the light emitted by the light cone 120. By providing the collimating lens 140, on the one hand, the emitted light can be incident on the LCD panel 130 in parallel, reducing the probability of light being reflected on the LCD panel 130, thereby facilitating improving the utilization rate of light. On the other hand, the light cone 120 is combined with the collimating lens 140, so that the output light of the collimating lens 140 presents a uniform light spot, which is also beneficial to further improve the uniformity of color on the LCD panel 130. Optionally, the collimating lens 140 can be, for example, a Fresnel lens.

[0097] A second embodiment of the present application provides a projection device, comprising the projection optical module 100 of the first embodiment.

[0098] The projection device of the present application uses the projection optical module 100 of the first aspect. In this way, the spectrum of the secondary reflected light at the edge of the light exit surface of the light cone 120 is defined by a formula to be the same as the spectrum of the light at the center of the light exit surface of the light cone 120, which is conducive to improving the problem of uneven color of the picture, and further helps to improve the display effect of the projection device.

[0099] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A projection optical module, characterized in that: include: light source; as well as A light cone, the light cone comprising a light incident surface, a light emitting surface opposite to the light incident surface, and a side surface connecting the light incident surface and the light emitting surface, the light source being disposed on the light incident surface, the light source comprising a plurality of light emitting chips arranged in an array on the light incident surface; The orthographic projection of the light cone on the first virtual plane is a polygon, the first virtual plane is perpendicular to the light incident surface, the polygon includes a first side and a second side that are arranged in parallel, the first side is the orthographic projection of the light incident surface on the first virtual plane, and the second side is the orthographic projection of the light emitting surface on the first virtual plane; On the first side, the normalized spectrum of the secondary reflection of the light emitted by the light source Satisfies the following formula: ； Wherein, λ is the wavelength of visible light of the light source, d is the length of the second side, h is the distance between any point of the first side and the endpoint of the first side, is the function of the spectrum of the light emitted by the light source after secondary reflection with respect to λ and h, is the normalized spectrum of visible light at the midpoint of the second side as a function of λ.

2. The projection optical module according to claim 1, characterized in that: The polygon is an isosceles trapezoid, and the orthographic projection of the side surface on the first virtual plane is the hypotenuse of the isosceles trapezoid; Said Satisfies the following formula: ； Wherein, A is the length of the first side, α is the angle between the extension lines of the two hypotenuses, θ is the critical angle between the incident light that is twice reflected in the light cone and the light incident surface, X1 is the incident angle of the incident light that is twice reflected in the light cone when it is first reflected on the side surface, and X2 is the incident angle of the incident light that is twice reflected in the light cone when it is secondly reflected on the side surface, is the reflectivity of the light cone reflection surface as a function of λ and the incident angle X, is a function of the spectrum of the incident light on the light incident surface with respect to λ and h.

3. The projection optical module according to claim 2, characterized in that: The X1, the X2 and the θ satisfy the following formula: ； ； ； Wherein, c is the length of the hypotenuse.

4. The projection optical module according to claim 2, characterized in that: The light source includes a middle area and a peripheral area surrounding the middle area, and the spectral intensity of the middle area and the spectral intensity of the surrounding area satisfy: ； ； Spectrum in the center of the picture Approximately meets: ； in, is the normalized spectrum at the center of the light source, is the reflectivity of the side surface of the light cone, is the visible light spectrum at the edge of the second side as a function of λ.

5. The projection optical module according to claim 4, characterized in that: The deviations of the blue peak wavelength, the green peak wavelength and the red peak wavelength of the spectrum in the peripheral region from the spectrum in the middle region are all within 10 nm.

6. The projection optical module according to claim 4, characterized in that: The light incident surface includes a central area and an edge area surrounding the central area, the projection of the middle area on the light incident surface coincides with the central area, and the projection of the peripheral area on the light incident surface coincides with the edge area; The first side includes a first segment and two second segments symmetrical about the first segment, the first segment is the orthographic projection of the central area on the first virtual plane, the second segment is the orthographic projection of the edge area on the first virtual plane, and the total length P of the two second segments and the length Y of the first segment satisfy: 1 / 3Y≤P≤2Y.

7. The projection optical module according to claim 6, characterized in that: The central area has a first center, the orthographic projection of the first center on the first virtual plane is the midpoint of the first section, and the blue light peak intensity of the light source located in the edge area is 101.2% to 109.3% of the blue light peak intensity of the light source located in the first center; And / or, the peak intensity of green light of the light source located in the edge area is 89.3% to 99.7% of the peak intensity of green light of the light source located in the first center.

8. The projection optical module according to claim 1, characterized in that: The light emitting surface and the light incident surface are in a shape of a square or a rectangle.

9. The projection optical module according to claim 1, characterized in that: The projection optical module further comprises an LCD panel arranged on a side of the light cone away from the light source, and a collimating lens arranged between the LCD panel and the light cone.

10. A projection device, characterized in that: Comprising the projection optical module as described in any one of claims 1-9.

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