CN114253056A - Projection system - Google Patents

Abstract

The application discloses projection system belongs to the projection display field. Because the light valve driving board and the lens component in the projection system are arranged along the direction parallel to the projection screen, the board surface of the first circuit board in the light valve driving board is vertical to the projection screen, and the board surface of the display board is parallel to the projection screen. Therefore, the arrangement mode can effectively shorten the number of the optical lenses arranged on the lens component in the direction perpendicular to the projection screen, further shorten the distance between the light emitting side of the lens component and the projection screen, reduce the projection ratio of the projection system, and be applicable to the ultra-short-focus projection system.

Description

Projection system

The embodiments of the present application claim priority from the chinese patent application, entitled "projection system," filed on 25/9/2020, application number 202011025334.6, the entire contents of which are incorporated by reference herein.

Technical Field

The present disclosure relates to the field of projection display, and more particularly, to a projection system.

Background

At present, a projection system may include a lens assembly, a light valve driving board, and a display board, where a plurality of optical lenses included in the lens assembly are arranged in a direction perpendicular to a projection screen, a light emitting side of the lens assembly is located on a side of the display board away from the projection screen, and a board surface of the light valve driving board and a board surface of the display board are both parallel to the projection screen.

However, the arrangement of the lens assembly, the light valve driving board and the display panel makes the distance between the light emitting side of the lens assembly and the projection screen larger, which results in larger projection of the projection system.

Disclosure of Invention

The embodiment of the disclosure provides a projection system, which can solve the problem that the arrangement mode of a lens assembly, a light valve driving board and a display board in the related art cannot be applied to an ultra-short-focus projection system. The technical scheme is as follows:

in one aspect, a projection system is provided, the projection system comprising: lens assembly, display panel and light valve driver board; the light valve driving board comprises a circuit board and a light valve positioned on the circuit board;

the display panel is positioned on one side of the lens assembly close to the projection screen, and is electrically connected with the light valve driving board and used for providing a light valve control signal for the light valve;

the light valve driving board and the lens assembly are arranged along a first direction, the first direction is parallel to the projection screen, and the light valve is used for turning over under the driving of the light valve control signal and transmitting a light beam to the lens assembly;

the panel surface of the circuit board is perpendicular to the projection screen, and the panel surface of the display panel is parallel to the projection screen.

Optionally, the projection system further includes: differential signal lines and a backplane; the display panel, the light valve driving board and the lens assembly are all positioned on the bottom plate, and the differential signal line is in contact with the bottom plate;

the display panel and the light valve driving board are electrically connected through the differential signal line.

Optionally, the projection system further includes: a shielding layer;

the shielding layer wraps the outer side of the differential signal line and is grounded.

Optionally, the projection system further includes: the magnetic ring is sleeved on the outer side of the shielding layer, and the length of the magnetic ring is smaller than that of the shielding layer.

Optionally, the projection system further includes: a common mode inductor;

the common mode inductor is connected in series between the display panel and the light valve driving board through the differential signal line.

Optionally, the distance between the display panel and the light valve driving board is determined according to a communication rate between a light valve driving assembly in the display panel and the light valve.

Optionally, the communication rate between the light valve driving assembly and the light valve is less than or equal to 1.6 gbits per second, and the distance between the display panel and the light valve driving board is less than or equal to 254 mm.

Optionally, the projection system further includes: a light source assembly and a light transmitting assembly; the lens assembly comprises a first lens subassembly, a reflective subassembly and a second lens subassembly, and an optical axis of the first lens subassembly intersects an optical axis of the second lens subassembly;

the light transmission assembly is positioned between the light source assembly and the light valve driving board and is used for transmitting the light beams emitted by the light source assembly to the light valve driving board;

the light valve driving board is located on the light incident side of the first lens subassembly and is used for transmitting the light beam transmitted by the light transmission assembly to the first lens subassembly under the driving of the light valve control signal;

the reflection subassembly is located between the first lens subassembly and the second lens subassembly, the first lens subassembly is used for transmitting the light beam to the reflection subassembly, the reflection subassembly is used for reflecting the light beam to the second lens subassembly, and the second lens subassembly is used for projecting the light beam to a projection screen.

Optionally, an optical axis of the first lens subassembly is perpendicular to an optical axis of the second lens subassembly, and the optical axis of the second lens subassembly is perpendicular to the projection screen.

Optionally, the light transmission assembly is configured to adjust a transmission direction of the light beam emitted by the light source assembly from a second direction to a third direction, and transmit the light beam to the light valve driving board after being adjusted from the third direction to the first direction;

wherein the second direction intersects the third direction, the second direction and the first direction are both parallel to an optical axis of the first lens subassembly, and the first direction and the second direction are opposite.

The beneficial effects brought by the technical scheme provided by the embodiment of the disclosure at least comprise:

the embodiment of the disclosure provides a projection system, because a light valve driving board and a lens assembly in the projection system are arranged along a direction parallel to a projection screen, and a board surface of a first circuit board in the light valve driving board is perpendicular to the projection screen, and a board surface of a display board is parallel to the projection screen. Therefore, the arrangement mode can effectively shorten the number of the optical lenses arranged on the lens component in the direction perpendicular to the projection screen, further shorten the distance between the light-emitting side of the lens component and the projection screen, reduce the projection ratio of the projection system, and be applicable to the ultra-short-focus projection system.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a projection system provided in an embodiment of the present disclosure;

fig. 2 is a schematic diagram of a display panel connected to a light valve driving board according to an embodiment of the present disclosure;

fig. 3 is a schematic diagram of a differential signal line provided by the present disclosure, in which a shielding layer is wrapped and a magnetic ring is sleeved on the shielding layer;

fig. 4 is a schematic diagram of a first circuit board provided with a common mode inductor according to an embodiment of the disclosure;

fig. 5 is a schematic diagram of a second circuit board provided with a common mode inductor according to an embodiment of the disclosure;

FIG. 6 is a schematic diagram of another projection system provided by embodiments of the present disclosure;

FIG. 7 is a schematic diagram of a projection system according to an embodiment of the disclosure;

FIG. 8 is a schematic diagram of a projection system according to another embodiment of the disclosure;

fig. 9 is a schematic diagram illustrating a distance between a light-emitting side of a second lens subassembly and a projection screen according to an embodiment of the disclosure;

FIG. 10 is a schematic diagram of a projection system according to another embodiment of the disclosure;

fig. 11 is a schematic structural diagram of an illumination system provided by the embodiment of the present disclosure;

fig. 12 is a partial schematic view of a second circuit board according to an embodiment of the disclosure;

fig. 13 is a partial schematic view of a second circuit board according to an embodiment of the disclosure;

FIG. 14 is a diagram illustrating results obtained by testing the low-frequency radiation disturbance field strength of the projection system according to an embodiment of the disclosure;

fig. 15 is an eye diagram of a light valve provided by an embodiment of the present disclosure receiving a differential signal transmitted by a light valve driving component;

FIG. 16 is a schematic diagram of a projection system according to an embodiment of the disclosure;

fig. 17 is a schematic structural diagram of a projection system provided in the related art.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a projection system provided in an embodiment of the present disclosure. As shown in fig. 1, the projection system may include a lens assembly 10, a display panel 20, and a light valve driving board 30. Wherein, referring to fig. 2, the light valve driving board 30 may include a first circuit board 301 and a light valve 302 on the first circuit board 301. Alternatively, the first circuit board 301 may be a Printed Circuit Board (PCB).

The display panel 20 is located on a side of the lens assembly 10 adjacent to the projection screen 40, and the display panel 20 is electrically connected to the light valve driving board 30 for providing the light valve control signal to the light valve 302.

The light valve driving board 30 and the lens assembly 10 are arranged in a first direction V, which is parallel to the projection screen 40. The light valve 302 is driven by the light valve control signal to flip and transmit the light beam to the lens assembly 10. The lens assembly 10 is used for projecting the light beam to the projection screen 40 to realize the display of the image.

The first circuit board 301 has a surface perpendicular to the projection screen 40, and the display panel 20 has a surface parallel to the projection screen 40.

In the disclosed embodiment, the projection system may include a housing 00, the housing 00 having an accommodating space, and the lens assembly 10, the display panel 20, and the light valve driving board 30 are all located within the housing 00.

In summary, the embodiments of the present disclosure provide a projection system, in which a light valve driving board and a lens assembly are arranged in a direction parallel to a projection screen, and a board surface of a first circuit board in the light valve driving board is perpendicular to the projection screen, and a board surface of a display board is parallel to the projection screen. Therefore, the arrangement mode can effectively shorten the number of the optical lenses arranged on the lens component in the direction perpendicular to the projection screen, further shorten the distance between the light emitting side of the lens component and the projection screen, reduce the projection ratio of the projection system, and be applicable to the ultra-short-focus projection system.

Referring to fig. 2 and 3, the projection system may further include a differential signal line 50 and a backplane 60. The display panel 20, the light valve driving board 30 and the lens assembly 10 are all located on the base plate 60, the differential signal line 50 is in contact with the base plate 60, and the base plate 60 is grounded. The material of the bottom plate 60 may be a metallic material, for example, iron.

The display panel 20 and the light valve driving board 30 are electrically connected by a differential signal line 50. The display panel 20 may provide an optical valve control signal to the light valves 302 in the light valve driving board 30 through the differential signal line 50.

Alternatively, the differential signal line 50 may be a low-voltage differential signaling (LVDS) line. The display panel 20 may transmit control signals to the light valve 302 in an LVDS format. The control signals may include a differential mode signal, which is the light valve control signal, and a common mode signal, which is used to control the light valve 302 to flip. This common mode signal is not used to control the light valve 302 flipping. Since the bottom board 60 is grounded and the differential signal lines 50 are in contact with the bottom board 60, the common mode signal transmitted through the differential signal lines 50 can be guided to the ground, and the common mode signal is prevented from radiating to the outside of the housing and affecting users.

Referring to fig. 3, the projection system may further include a shielding layer 70, the shielding layer 70 is wrapped around the differential signal line 50, and the shielding layer 70 is grounded.

Alternatively, both ends of the shielding layer 70 may be grounded, or one end may be grounded. The material of the shielding layer 70 may be a metal material, for example, the metal material may be red copper or tin-plated copper. The shielding layer 70 may be a mesh braid.

Because the shielding layer 70 wraps the differential signal line 50, and the shielding layer 70 is grounded, the common-mode signal transmitted by the differential signal line 50 can be conducted to the ground through the shielding layer 70, so that the common-mode signal is shielded inside the projection system, the situation that the common-mode signal transmitted by the differential signal line is radiated to the outer side of the shell 00 to influence a user is avoided, and the influence on the user is reduced. Meanwhile, the common-mode interference of the projection system is ensured to meet the requirement of the electromagnetic compatibility limit value, and the projection system can pass the electromagnetic interference (EMI) test, so that the projection system is ensured to be qualified.

Referring to fig. 3, the shield layer 70 is connected to the chassis base 60. Since the materials of the shielding layer 70 and the bottom plate 60 are both metal materials, and the bottom plate 60 is grounded. Therefore, the shield layer 70 is connected to the base plate 60, and the ground of the shield layer 70 can be realized.

Alternatively, both ends of the shielding layer 70 may be directly connected to the chassis base 60. Alternatively, both ends of the shielding layer 70 may be connected to the chassis 60 by metal wires. Alternatively, one end of the shielding layer 70 may be directly connected to the chassis 60, and the other end of the shielding layer 70 may be connected to the chassis 60 through a metal wire.

In an alternative implementation manner of the embodiment of the present disclosure, referring to fig. 3, the projection system may further include a magnetic ring 80, the magnetic ring 80 is sleeved outside the shielding layer 70, and the length of the magnetic ring 80 is smaller than the length of the shielding layer 70, that is, the magnetic ring 80 only covers a part of the shielding layer 70. By sleeving the magnetic ring 80 on the outer side of the shielding layer 70, the impedance on the common mode current transmission path, that is, the impedance of the differential signal line 50 can be increased, so that the common mode signal can be effectively suppressed, the common mode current on the differential signal line can be reduced, and the common mode signal radiated to the outside of the housing can be reduced.

In another alternative implementation of the disclosed embodiment, the projection system may further include a common mode inductor connected in series between the display panel 20 and the light valve driving board 30 via a differential signal line 50. By connecting a common mode inductor in series between the display panel 20 and the light valve driving board 30, the impedance of the common mode current transmission path, that is, the impedance of the differential signal line 50 can be increased, so that the common mode signal generated by the display panel 20 can be effectively suppressed, and the common mode current on the differential signal line can be reduced, thereby reducing the common mode signal radiated to the outside of the housing.

Optionally, referring to fig. 4, the first circuit board 301 included in the light valve driving board 30 is further provided with a first common mode inductor 303, and the first common mode inductor 303 is connected in series between the display panel 20 and the light valve driving board 30 through the differential signal line 50. Alternatively, referring to fig. 5, the display panel 20 may include a second circuit board 201, and the second circuit board 201 may be provided with a light valve driving assembly 202 and a second common mode inductor 203, and the second common mode inductor 203 may be connected in series between the display panel 20 and the light valve driving board 30 through the differential signal line 50. Alternatively, the first circuit board 301 may have a first common mode inductor 303 disposed thereon, and the second circuit board 201 may have a second common mode inductor 203 disposed thereon.

Referring to fig. 6 and 7, the distance d1 between display panel 20 and light valve driving board 30 may be determined according to the communication rate between light valve driving assembly 202 and light valve 302. Alternatively, the distance d1 between the display panel 20 and the light valve driving board 30 is the distance between the first circuit board 301 and the second circuit board 201.

Optionally, the communication rate between the light valve driving assembly 202 and the light valve 302 is less than or equal to 1.6 gigabits per second (Gbts), and the distance between the display panel 20 and the light valve driving board 30 is less than or equal to 254 millimeters (mm), i.e., the distance between the first circuit board 301 and the second circuit board 201 is less than or equal to 254 mm. Thereby ensuring that the differential signal (i.e., the light valve control signal described above) received by the light valve 302 is of good quality.

Referring to fig. 8, the projection system can further include a light source assembly 90 and a light delivery assembly 91. The lens assembly 10 may include a first lens subassembly 101, a reflective subassembly 102 and a second lens subassembly 103, wherein an optical axis X1 of the first lens subassembly 101 intersects an optical axis X2 of the second lens subassembly 103, that is, an arrangement direction of optical lenses included in the first lens subassembly 101 is not parallel to an arrangement direction of optical lenses included in the second lens subassembly 103. Optionally, the light source assembly 90 is used for emitting a laser beam. The reflective sub-assembly 102 may be a mirror or a prism.

The light transmission assembly 91 is positioned between the light source assembly 90 and the light valve driving board 30, and transmits the light beam emitted from the light source assembly 90 to the light valve driving board 30.

The light valve driving board 30 is located on the light incident side of the first lens subassembly 101, and is used for transmitting the light beam transmitted by the light transmission assembly 91 to the first lens subassembly 101 under the driving of the light valve control signal.

The reflection sub-assembly 102 is located between the first lens sub-assembly 101 and the second lens sub-assembly 103, and the first lens sub-assembly 101 is used for transmitting the light beam to the reflection sub-assembly 102. The reflection sub-assembly 102 is used for reflecting the light beam to the second lens sub-assembly 103, and the second lens sub-assembly 103 is used for projecting the light beam to the projection screen 40 so as to display the image on the projection screen 40. Namely, the light-emitting side of the lens assembly 10 is the light-emitting side of the second lens subassembly 103.

In the embodiment of the present disclosure, the reflection sub-assembly 102 may be located between any two adjacent optical lenses of the plurality of optical lenses included in the lens assembly 10, and the embodiment of the present disclosure does not limit the specific location of the reflection sub-assembly 102.

In the embodiment of the present disclosure, the projection system may be an ultra-short focus projection system, and referring to fig. 9, since the light-emitting side of the lens assembly 10 is the light-emitting side of the second lens subassembly 103, the distance D between the second lens subassembly 103 and the projection screen 40 is the distance between the light-emitting side of the lens assembly 10 and the projection screen 40. Compared with the related art, the lens assembly includes optical lenses arranged in a direction perpendicular to the projection screen. In the embodiment of the present disclosure, only the optical lenses (i.e., the second lens subassembly 103) in the lens assembly 10 are arranged along the X2 direction, and the other optical lenses (i.e., the first lens subassembly 101) are arranged along the X1 direction, so that the number of the optical lenses arranged along the X2 direction is effectively reduced, and the distance D between the light emitting side of the second lens subassembly 103 and the projection screen 40 can be effectively shortened. Based on the above analysis, compared with the related art, the arrangement manner of the plurality of components in the projection system provided by the embodiment of the disclosure effectively shortens the distance between the light-emitting side of the lens component and the projection screen, and reduces the throw ratio of the projection system, and the arrangement manner can be applied to an ultra-short-focus projection system.

Referring to fig. 10, the position of the first reflector 1030 in the plurality of optical lenses that the second lens subassembly 103 may include is the light exit side of the second lens subassembly 103. The first mirror 1030 is used to reflect the light beam to the projection screen 40.

Referring to fig. 10, the optical axis X1 of the first lens subassembly 101 is perpendicular to the optical axis X2 of the second lens subassembly 103, and the optical axis X2 of the second lens subassembly 103 is perpendicular to the projection screen 40.

Referring to fig. 10, the light transmission assembly 91 is configured to adjust the transmission direction of the light beam emitted by the light source assembly 90 from the second direction to a third direction, and to transmit the light beam adjusted from the third direction to the first direction V to the light valve driving board 30. Therefore, the distance between the light source assembly 90 and the lens assembly 10 in the first direction is short, the length of the optical engine in the direction of the optical axis X1 is shortened, and the volume of the projection system is reduced. The optical engine may include the above-described light source assembly 90, the light transmission assembly 91, the lens assembly 10, and the light valve driving board 30.

Wherein the second direction intersects with the third direction, the second direction and the first direction V are both parallel to the optical axis X1 of the first lens subassembly 101, and the first direction V and the second direction are opposite.

Referring to fig. 10, the optical transmission assembly 91 may include a first optical transmission subassembly 910 and a second optical transmission subassembly 911. The first light transmitting subassembly 910 is located at the light emitting side of the light source assembly 90, and the second light transmitting subassembly 911 is located between the first light transmitting subassembly 910 and the light valve driving board 30.

Referring to fig. 10, the first light transmission sub-assembly 910 may include a plurality of optical lenses sequentially arranged in a transmission direction of a light beam. Alternatively, the plurality of optical lenses may include a mirror, a focusing lens, a collimating lens, and the like. The plurality of optical lenses are used for sequentially transmitting the light beams emitted by the light source assembly 90 to the second light-transmitting subassembly 911.

Referring to fig. 11, the second light transmitting subassembly 911 may include a light pipe 9111, a first mirror 9112, a second mirror 9113, a second mirror 9114, a third mirror 9115, and a third mirror 9116 arranged in that order along the optical axis X1. The light guide 9111 is configured to homogenize the light beam transmitted by the first light transmission subassembly 910, and transmit the homogenized light beam to the first lens 9112 and the second lens 9113 in sequence. The second mirror 9113 is configured to transmit the light beam to the second mirror 9114, the second mirror 9114 is configured to reflect the light beam to the third mirror 9115, and the third mirror 9115 then transmits the light beam to the third mirror 9116. The third mirror 9226 reflects the beam to the light valve 302 on the light valve driving board 30.

Alternatively, the first lens 9112 and the third lens 9115 can be spherical lenses and the second lens 9113 can be aspheric lenses.

In the embodiment of the present disclosure, the panel surface of the display panel 20 does not intersect with the optical axis X1 of the first lens subassembly 101 and the optical axis X2 of the second lens subassembly 103, so that the problem that the display panel 20 blocks light beams can be avoided, and the display effect of images can be ensured.

The position of the display panel is not limited by the embodiment of the disclosure as long as the display panel can be ensured to be not intersected with the optical axis X1 of the first lens subassembly 101 and the optical axis X2 of the second lens subassembly 103, and the length of the differential signal line 50 is less than or equal to 254 mm.

In the embodiment of the present disclosure, referring to fig. 10, the distance D0 between the light valve driving board 30 and the display panel 20 in the direction along the optical axis X2 is less than a distance threshold equal to a first difference between the first distance and the second distance D1.

Wherein, the first distance is a distance D between the light emitting side of the first lens subassembly 101 and the projection screen 40, referring to fig. 10, the second distance D1 is a distance between the first lens subassembly 101 and the first circuit board 301 in the light valve driving board 30 in the direction of the optical axis X2. I.e., D0< D-D1.

For example, if D is 215mm, D1 is 197.5mm, and since 215-197.5 is 17.5, D0 is <17.5 mm.

Alternatively, the distance threshold is equal to the difference between the first difference and a second difference between the thickness w of the housing of the projection system and the safety spacing s, i.e. D0< D-D1-w-s. The safety spacing s is the safety distance that needs to be maintained between the display panel and the housing.

For example, if D215 mm, D1 197.5mm, w 3mm, s 2mm, D0<12.5mm since 215-197.5-3-2 is 12.5.

In the embodiment of the present disclosure, referring to fig. 12, the display panel 20 may further include a plurality of pairs of first traces 204 and a first socket 205 on the second circuit board 201, each pair of first traces 204 includes two first traces 204, one end of the plurality of pairs of first traces 204 is connected to the light valve driving assembly 202, and the other end is connected to the first socket 205. The two first traces 204 included in each pair of first traces 204 have the same pitch, the same length, and the same width, and the two adjacent pairs of first traces 204 have the same pitch, the same length, and the same width. The distance between any first trace 204 and the other traces except the first trace is at least 3 times of the line width of the first trace 204.

The light valve driving board 30 may further include a plurality of pairs of second traces 304, a second socket 305 and a third socket 306 on the first circuit board 301, each pair of second traces 304 includes two second traces 304, one end of the plurality of pairs of second traces 304 is connected to the second socket 305, the other end of the plurality of pairs of second traces 304 is connected to the third socket 306, and the third socket 306 is connected to the light valve 302. The two second traces 304 included in each pair of second traces 304 have the same pitch, the same length, and the same width, and the two adjacent pairs of second traces 304 have the same pitch, the same length, and the same width. The distance between any one of the second traces 304 and the other traces except the second trace 304 is at least 3 times the line width of one of the second traces 304. In the embodiment of the present disclosure, the first trace and the second trace are both LDVS traces.

The differential trace 50 may also include a plurality of pairs of differential signal lines 50, where each pair of differential signal lines 50 includes two differential signal lines 50. The pairs of differential signal lines 50 are connected at one end to the first socket 205 and at the other end to the second socket 305, thereby realizing the connection of the display panel 20 and the light valve driving board 30. The lengths and the widths of the cross-sectional areas of two adjacent pairs of differential signal lines 50 are the same, the two differential signal lines 50 included in each pair of differential signal lines 50 have the same length and the same width, and the distance between the two differential signal lines 50 is less than half of the distance between the pair of differential signal lines 50 and the shielding layer 70. The differential mode impedance of the two differential signal lines 50 lies within an impedance range of [99.9, 100.1 ].

Referring to fig. 12, the common mode current transmitted by the light valve driving component 202 flows through the first trace 204, the differential signal line 50 and the second trace 304, and therefore the common mode signal corresponding to the common mode current is transmitted through the first trace 204, the differential signal line 50 and the second trace 304. The mode of arranging the first wiring, the differential signal line and the second wiring can effectively reduce common-mode current, thereby reducing common-mode signals and further reducing the common-mode signals radiated to the outer side of the shell. And the shielding layer is wrapped on the differential signal wire, so that the common-mode signal can be conducted to the bottom plate 60 and conducted to the ground 01 through the bottom plate 60, and the common-mode signal radiated to the outer side of the shell is further reduced.

In the disclosed embodiment, the differential mode impedance of each pair of first traces 204 and each pair of second traces 304 is within an impedance range, which is [99.9, 100.1 ]. The pair of first traces and the pair of second traces may be referred to as microstrip differential lines. Taking the first trace 204 as an example, referring to fig. 13, the second circuit board 201 may include an insulating layer 206 and a conductive layer 207, the first trace 204 is located between the insulating layer 206 and the conductive layer 207, and the conductive layer 207 may be green oil. The differential mode impedance Z1 of each pair of first tracks satisfies: z1 is 2 × Z2 × (1-k), where Z2 is the characteristic impedance of a single microstrip line, i.e., the characteristic impedance of one first trace 204, and k is the coupling coefficient of each pair of first traces.

Wherein the content of the first and second substances,

the

Referring to fig. 13, the S1 is a space between two first traces 204 included in each pair of first traces 204, and the W1 is a width of the conductive layer 207 covering one first trace 204 on a side close to the insulating layer 206. Er1 is the dielectric constant of the material of insulating layer 206, and H1 is the thickness of insulating layer 206. W2 is the width of the conductive layer 207 covering one first trace 204 at the side far from the insulating layer 206, and T1 is the thickness of one first trace 204.

Assuming S1 ≈ 7.5, K ≈ 0.097, H1 ═ 4.5, Er1 ═ 4.5, W1 ═ 5.5, and W2 ═ 4.5, this example shows that

Then Z1 ≈ 99.19 ohms (Ω) ≈ 100 Ω.

The common mode impedance of each pair of first traces 204 is a parallel approximation of the characteristic impedance of the two first traces. If the common mode impedance Z3 satisfies:

the N is a coupling degree between the shielding layer and the first trace 204.

Assuming N1.14 and Z2 54.92, the result is that

If the differential signal line 50 is approximated to a monopole antenna, the radiation electric field intensity E of the common mode current flowing through the differential signal line 50 satisfies:

where I is a common mode current flowing through the differential signal line 50, and has a unit of ampere (a). f represents the sinusoidal frequency of the common mode current component in hertz (Hz). L is the length of the differential signal line 50 in meters (m). R denotes the distance of the test equipment from the differential signal line 50 in m.

For example, if the common mode current is 5 × 10^-3A, L1 m, R3 m, and f 100MHz, then

This 2000 μ V/m is greater than the quasi-peak threshold of 40 μ V/m, and therefore the electromagnetic interference test of the projection system is not acceptable.

In the embodiment of the present disclosure, the radiation electric field intensity E of the common mode current can be reduced by reducing the length of the differential signal line 50, thereby ensuring that the electromagnetic interference test of the projection system is qualified.

The distance between the display panel 20 and the light valve driving board 30 is less than or equal to 254mm, the shielding layer 70 is wound on the differential signal line 50, the shielding layer 70 is sleeved with the magnetic ring 80 or the projection system comprises a common mode inductor, and the differential mode impedances of the differential signal line, the first routing line and the second routing line are all in the impedance range, and the projection system is subjected to far-field low-frequency radiation disturbance field strength test through test equipment. Fig. 14 is a schematic diagram illustrating a result obtained by performing a low-frequency radiation disturbance field strength test on a projection system according to an embodiment of the disclosure. As shown in fig. 14, the abscissa in the result diagram represents the test frequency of the test equipment, i.e., the operating frequency of the antenna in the test equipment, which is expressed in megahertz (MHz). The test frequency range is 30 MHz-1000 MHz. The ordinate in the resulting diagram represents the quasi-peak value of the electromagnetic signal, which has the unit μ V/m.

The first curve Y1 in the diagram is a quasi-peak graph of the electromagnetic signal radiated by the projection system in the range of the test frequency from 30MHz to 1000MHz, and a larger quasi-peak value of the electromagnetic signal of the projection system indicates that the electromagnetic signal radiated by the projection system is stronger, and the electromagnetic signal includes the common-mode signal. A second curve Y2 in the result schematic diagram is a quasi-peak threshold curve graph of the electromagnetic signal meeting the civil-grade CISPR22Class B low-frequency radiation disturbance field strength test within the test frequency range of 30 MHz-1000 MHz.

If any quasi-peak value in the first curve Y1 is located above the second curve Y2, it can be determined that the projection system radiates more electromagnetic signals and cannot meet the use requirement. If the first curve Y1 is located below the second curve Y2, it can be determined that the projection system radiates less electromagnetic signals, which satisfies the usage requirement.

As can be seen from fig. 14, in the range of the test frequency from 30MHz to 1000MHz, the first curve Y1 is located below the second curve Y2, i.e., at any test frequency, the quasi-peak value of the electromagnetic signal radiated by the projection system is smaller than the corresponding quasi-peak threshold value. Therefore, the projection system passes the low-frequency radiation field intensity disturbance test of civil-grade CISPR22Class B, and meets the use requirement.

Table 1 shows debugging parameters of the test equipment, a quasi-peak value of an electromagnetic signal radiated by the projection system, a quasi-peak threshold value of the electromagnetic signal, and a difference value between the quasi-peak threshold value and the quasi-peak value in a process of testing the projection system by the test equipment. The debugging parameters may include a test frequency of the test equipment, a test duration, a height of the test equipment from the bottom surface, a polarity, and an angle of an antenna in the test equipment. Wherein, the polarity is H, which indicates that the antenna of the testing device is not perpendicular to the projection system. The duration of the test is in ms and the bandwidth is in kilohertz (kHz), which is in centimeters (cm).

As can be seen from table 1, if the test frequency of the test apparatus is 152.1790MHz, the quasi-peak value of the electromagnetic signal radiated by the projection system is 32.81, and the quasi-peak threshold value is 40, and since the quasi-peak value 32.81 is smaller than the quasi-peak threshold value 40, it can be determined that the electromagnetic signal radiated by the projection system is smaller when the test frequency of the test apparatus is 152.1790 MHz.

TABLE 1

Under the above-mentioned scenario, fig. 15 is an eye diagram of a light valve provided by the present disclosure, which receives a differential signal transmitted by a light valve driving component. As shown in fig. 15, the abscissa of the eye diagram is time in picoseconds (ps), and the ordinate is the voltage of the differential signal received by the light valve 302 in millivolts (mV).

As can be seen from fig. 15, the voltage of the differential signal received by the light valve 302 is between the first threshold and the second threshold, and the difference between the maximum voltage of the differential signal and the first threshold is larger, and the difference between the minimum voltage of the differential signal and the second threshold is also larger. Wherein the first threshold value is 400mV, and the second threshold value is-400 mV. Meanwhile, the voltages of the cross point P1 and the cross point P2 in the differential signal are both small, which indicates that the jitter of the differential signal is small, i.e., the quality of the differential signal is good, and the probability of error occurrence of the differential signal is low. In summary, it can be seen that when the distance between the display panel 20 and the light valve driving board 30 is less than or equal to 254mm, the quality of the differential signal received by the light valve is better.

In the disclosed embodiment, referring to fig. 16, the projection system may further include a heat sink 92 and a duct 93, one end of the duct 93 being connected to the heat sink 92, and the other end being connected to the support plate where the light source assembly is located. The heat sink 92 dissipates heat from the light source assembly through the conduit 93.

Referring to fig. 16, the projection system may further include a power board 94, the power board 94 being located at one side of the second lens subassembly 103.

Fig. 17 is a schematic structural diagram of a projection system provided in the related art. As shown in fig. 17, the projection system may include a lens assembly 001, a light valve driving board 002 and a display board 003, wherein a plurality of optical lenses included in the lens assembly 001 are arranged in a direction perpendicular to the projection screen 004, a light emitting side of the lens assembly 001 is located on a side of the display board 20 away from the projection screen 004, and a board surface of the light valve driving board 002 and a board surface of the display 3 are both parallel to the projection screen 004.

However, the lens assembly 001, the light valve driving board 002 and the display panel 003 are arranged in such a way that the distance between the light emitting side of the lens assembly 001 and the projection screen 004 is large, which results in a large projection ratio of the projection system.

In the related art, if the throw ratio of the projection system is decreased, the total length of the lens assembly needs to be increased in order to ensure the image display effect, and the increase of the total length of the lens assembly causes the throw ratio of the projection system to increase, so that the throw ratio and the lens assembly cannot be balanced.

In the embodiment of the disclosure, because the optical axis of the first lens subassembly and the optical axis of the second lens subassembly that the lens subassembly in this projection system includes do not intersect, make the optical lens of middle part of the lens subassembly arrange along the optical axis direction of the second lens subassembly, all the other optical lens arrange along the optical axis direction of the first lens subassembly, therefore, the number of the optical lens of arranging along the optical axis direction of the second lens subassembly has effectively been reduced, and then the distance between the light-emitting side of the second lens subassembly and the projection screen has been shortened, the throw ratio of projection system has been reduced, this kind of arrangement mode can be applicable to in the ultra-short focus projection system. And the arrangement mode can reduce the projection ratio without increasing the total length of the lens assembly, thereby ensuring the balance of the two.

In summary, the embodiments of the present disclosure provide a projection system, in which a light valve driving board and a lens assembly are arranged in a direction parallel to a projection screen, and a board surface of a first circuit board in the light valve driving board is perpendicular to the projection screen, and a board surface of a display board is parallel to the projection screen. Therefore, the arrangement mode can effectively shorten the number of the optical lenses arranged on the lens component in the direction perpendicular to the projection screen, further shorten the distance between the light-emitting side of the lens component and the projection screen, reduce the projection ratio of the projection system, and be applicable to the ultra-short-focus projection system.

The above description is intended to be exemplary only and not to limit the present disclosure, and any modification, equivalent replacement, or improvement made without departing from the spirit and scope of the present disclosure is to be considered as the same as the present disclosure.

Claims (10)

1. A projection system, characterized in that the projection system comprises: lens assembly, display panel and light valve driver board; the light valve driving board comprises a circuit board and a light valve positioned on the circuit board;

the display panel is positioned on one side of the lens assembly close to the projection screen, and is electrically connected with the light valve driving board and used for providing a light valve control signal for the light valve;

the light valve driving board and the lens assembly are arranged along a first direction, the first direction is parallel to the projection screen, and the light valve is used for turning over under the driving of the light valve control signal and transmitting a light beam to the lens assembly;

the panel surface of the circuit board is perpendicular to the projection screen, and the panel surface of the display panel is parallel to the projection screen.

2. The projection system of claim 1, further comprising: differential signal lines and a backplane; the display panel, the light valve driving board and the lens assembly are all positioned on the bottom plate, and the differential signal line is in contact with the bottom plate;

the display panel and the light valve driving board are electrically connected through the differential signal line.

3. The projection system of claim 2, further comprising: a shielding layer;

the shielding layer wraps the outer side of the differential signal line and is grounded.

4. The projection system of claim 3, further comprising: the magnetic ring is sleeved on the outer side of the shielding layer, and the length of the magnetic ring is smaller than that of the shielding layer.

5. The projection system of claim 2, further comprising: a common mode inductor;

the common mode inductor is connected in series between the display panel and the light valve driving board through the differential signal line.

6. The projection system of any of claims 1 to 5, wherein the distance between said display panel and said light valve driving board is determined based on the rate of communication between a light valve driving assembly in said display panel and said light valve.

7. The projection system of claim 6, wherein a communication rate between the light valve driving assembly and the light valve is less than or equal to 1.6 gigabits per second, and wherein a distance between the display panel and the light valve driving panel is less than or equal to 254 millimeters.

8. The projection system of any of claims 1 to 5, further comprising: a light source assembly and a light transmitting assembly; the lens assembly comprises a first lens subassembly, a reflective subassembly and a second lens subassembly, and an optical axis of the first lens subassembly intersects an optical axis of the second lens subassembly;

the light transmission assembly is positioned between the light source assembly and the light valve driving board and is used for transmitting the light beams emitted by the light source assembly to the light valve driving board;

the light valve driving board is located on the light incident side of the first lens subassembly and is used for transmitting the light beam transmitted by the light transmission assembly to the first lens subassembly under the driving of the light valve control signal;

the reflection subassembly is located between the first lens subassembly and the second lens subassembly, the first lens subassembly is used for transmitting the light beam to the reflection subassembly, the reflection subassembly is used for reflecting the light beam to the second lens subassembly, and the second lens subassembly is used for projecting the light beam to a projection screen.

9. The projection system of claim 8, wherein an optical axis of the first lens subassembly is perpendicular to an optical axis of the second lens subassembly, and wherein an optical axis of the second lens subassembly is perpendicular to the projection screen.

10. The projection system of claim 8, wherein the light transmission assembly is configured to transmit the light beam emitted by the light source assembly to the light valve driving board after adjusting the transmission direction of the light beam from the second direction to a third direction and from the third direction to the first direction;

wherein the second direction intersects the third direction, the second direction and the first direction are both parallel to an optical axis of the first lens subassembly, and the first direction and the second direction are opposite.

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