CN108594433A - A high-efficiency head-up display lighting system using a polarized light converter - Google Patents

Abstract

The invention relates to the technical field of display illumination, and particularly discloses a high-efficiency head-up display illumination system using a polarized light converter, which comprises a light-emitting unit, wherein a collimating lens is arranged in front of the light-emitting unit; a polarized light birefringent plate for receiving light rays incident from the light emitting unit and the collimating lens; the micro lens array is used for receiving incident P polarized light and S polarized light; and the polarized light conversion sheet is arranged on the light emergent side of the lens array. The invention divides the non-polarized light into P polarized light and S polarized light through the polarized light double refraction sheet and emits the light at different angles, the light is condensed and refracted by the micro lens array and then emits the light in the same direction and in a side-by-side symmetrical mode, and then the polarized light conversion sheet forms polarized light with the same property and guides the polarized light into the display, thereby reducing the light loss, improving the brightness of the display and reducing the power consumption.

Description

A high-efficiency head-up display lighting system using a polarized light converter

technical field

The invention relates to the technical field of display lighting, and specifically discloses a high-efficiency head-up display lighting system using a polarized light converter.

Background technique

A head up display (Head Up Display, hereinafter referred to as HUD) is composed of a box of a virtual image projection system and a light combiner (Combiner). In the early days, it was applied to fighter jets. Pilots can watch the scene ahead through the optical synthesizer, and at the same time, the device projects a virtual image to obtain information without looking down at the instrument panel. Due to the continuous advancement of technology, the more advanced automobile industry has gradually adopted the HUD system. In the HUD system, how to reduce the waste of light sources, provide sufficient brightness, reduce power consumption, and reduce heat dissipation requirements are critical to the HUD system. Reliability is particularly important under the harsh environmental conditions of automotive systems. Therefore, the design of the lighting system of the HUD needs to be carefully developed to take it to the next level.

The traditional head-up display lighting system, as shown in Figure 7 and Figure 8, includes: a plurality of light sources 60, each light source 60 is formed by a light-emitting diode 602 covered with a light-emitting cup 601, and After the light-emitting diode 602 emits the light source, the light is emitted outward through the light-emitting cup 601; since the light-emitting diode 602 is a small-area Lambertian light source, its luminous intensity and luminous angle have a cosine function ( cosine), and the function of the condenser cup 601 is to condense the diffused light source of the light-emitting diode 602, thereby forming a directional small angle to be closer to a large area of parallel light (the exit size of the condenser cup) direct light source.

A light guide column 61 is used to accommodate the above-mentioned light emitting source 60. The light guide column is a hollow cylinder with high reflectivity mirrors on all four sides. Taking the direction in the figure as the reference direction, the lower part is the light incident surface, and the upper part is the light output surface. , the light from the light source 60 can be mixed through the light-emitting cups 601 to achieve a uniform mixing effect, and the light can be emitted from the direction of the light-emitting surface of the light-guiding rod 61 .

A diffuser 62 is located at the other end of the light guide column 61 (i.e., the light-emitting surface). The effect of adding the diffuser 62 is to diffuse the light emitted from the light-exit surface of the light guide column 61 at an appropriate angle to form a uniform surface light source. As a backlight for the rear LCD panel 63, a conventional lighting system is formed.

In the traditional technology, the light emitting source 60 covers a light-emitting cup 601 with a light-emitting diode 602, and the light is reflected forward. When the light is reflected forward, the energy consumption has been lost, and when the light passes through the diffuser 62, the energy is lost. After depletion, although the illumination light becomes uniform and soft; but the angle of the light will also be diffused accordingly, and it is difficult to concentrate on a specific angle (the field of view of the HUD) and within the visual range (Eye-box) of the HUD. The use causes a waste of luminosity, and the white light source of the traditional lighting system absorbs more than half of the light energy through the polarizer in the rear liquid crystal display, which further weakens the intensity of the light source, and the light is easy to diffuse and difficult to concentrate. This is the traditional technology. Therefore, the HUD needs a better lighting system to make the HUD more quality and more competitive.

Contents of the invention

In order to overcome the disadvantages and deficiencies in the prior art, the object of the present invention is to provide a high-efficiency head-up display lighting system using a polarized light converter.

In order to achieve the above object, the present invention adopts the following solutions.

A high-efficiency head-up display lighting system using a polarized light converter comprising:

At least one light-emitting unit can emit powerful light forward; and a collimating lens is arranged in front of the light-emitting unit;

A polarized birefringent sheet is used to receive the incident light from the light-emitting unit and the collimating lens, and divide the incident non-polarized collimated light into P polarized light and S polarized light, and the two light rays are respectively emitted at different angles ;

A group of microlens arrays are used to receive the incident P polarized light and S polarized light; the microlens array is a transparent block structure, the light incident surface and the light exit surface of the microlens array are parallel to each other, and the light incident surface and the light exit surface are parallel to each other. A lens array surface opposite to the position is provided on the light-emitting surface; the lens array surface is provided with a plurality of continuous and closely arranged lens units, so that the light rays of P polarized light and S polarized light are collected and collected by the first lens unit. Refraction enters the corresponding lens units in the second lens array surface in a left-right cross-symmetrical manner, and the lens units on the second lens array surface change the direction of the light beam so that the P polarized light and the S polarized light are in the same direction and side-by-side injection;

A polarizing replacement film, which is arranged on the light-emitting side of the lens array; the polarizing replacement film is provided with coatings arranged at equal intervals to form a polarized light conversion area with phase delay characteristics and a light transmission area without phase delay characteristics ; The polarization conversion area and the light transmission area are all aligned with the lens unit in the microlens array, and a set of polarization conversion area and light transmission area each account for half of the area of a lens unit;

After the light passes through the polarizing conversion sheet, it forms polarized light of the same nature, which is used for liquid crystal display.

Further, the lens unit is an elongated cylindrical lens, and is opposite to the polarization conversion area and the light transmission area of the polarization conversion sheet.

Further, the microlens array is integrally formed.

Further, the microlens array is composed of two half-blocks with lens units; the two half-blocks are symmetrical block lenses, and the outsides of the two half-blocks protrude to form a plurality of continuous and Lens units that are closely packed and aligned with each other.

Further, the light emitting unit is a single light source, and the collimating lens is only one set.

Further, the collimator lens is an array composed of a plurality of optical elements.

Further, there are at least two light emitting units.

Further, the light emitting unit is a light emitting diode.

Further, the polarization conversion region on the polarization conversion sheet has a half-wave phase delay characteristic, and the phase delay axis of the polarization conversion sheet is 45 degrees to the electric field polarization direction of the polarized light.

The beneficial effects of the present invention: provide a high-efficiency head-up display lighting system using a polarized light converter, which divides non-polarized light into P polarized light and S polarized light through a polarized light birefringent sheet and emits it at different angles. The lens array condenses and refracts the light into the polarizing conversion sheet to form polarized light of the same nature that is introduced into the display, thereby reducing light loss, improving the brightness of the display, and reducing power consumption.

Description of drawings

Fig. 1 is a schematic plan view of an embodiment of the present invention.

Fig. 2 is a schematic perspective view of the three-dimensional structure of the embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a polarization conversion sheet according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a structure of a microlens array according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a structure of a second microlens array according to an embodiment of the present invention.

Fig. 6 is a schematic diagram of parallel use of light sources for illumination according to an embodiment of the present invention.

FIG. 7 is an exploded view of a light source system of a conventional head-up display.

FIG. 8 is a combined sectional view of a light source system of a conventional head-up display.

60 light sources

601 Spotlight Cup

602 light emitting diode

61 light guide column

62 diffusers

63 panels

10 light units

11 Collimating lens

20 Polarizing birefringent film

30 microlens array

30’ microlens array

31 Lens Array Surface

31A half block

31’ Lens Array Facet

310 lens unit

32 Lens Array Surfaces

32A half block

32' Lens Array Facet

320 lens unit

40 Polarization conversion film

41 Polarization conversion area

42 Translucent area

50 LCD monitors

L light

Ls light

Lp light.

Detailed ways

The main purpose of the present invention is to abandon the setting of the traditional diffuser, avoid the waste of energy, reduce the shortcomings of brightness, and adopt a new design of the lighting system, its structure is mainly provided with a polarized birefringent sheet in front of the light emitting unit, first The non-polarized collimated light incident by the light-emitting unit is divided into P-polarized light and S-polarized light, and they are emitted at different angles; then through a set of microlens arrays, the P-polarized light and S-polarized light are converged Light and refraction are emitted in the same direction and side by side in a symmetrical manner; after a polarized light conversion unit is used to convert the light into polarized light of the same nature, it is then introduced into the liquid crystal display for display, and excellent and high efficiency can be obtained. light source.

In order to achieve the above object, the preferred embodiment of the present invention can be achieved in the following ways:

A light-emitting unit is provided, which can emit strong light to the front; and a collimating lens is arranged in front of the light-emitting unit; a polarizing birefringent sheet is provided to receive the incident light from the light-emitting unit and the collimating lens, And the incident non-polarized collimated light is divided into P-polarized light and S-polarized light, and they are emitted at different angles; a set of microlens arrays is used to receive the incoming P-polarized light and S-polarized light, The microlens array includes two oppositely arranged lens array surfaces, and the opposite lens array surfaces are arranged symmetrically to each other, and respectively form a plurality of continuous and closely arranged lens units, so that the light rays of P polarized light and S polarized light Through the condensing and refraction of the lens unit, it enters the lens unit on the second lens array surface symmetrically from left to right, and each corresponding lens unit on the second lens array surface can change the direction of each light beam, so that P The polarized light and the S polarized light are emitted in the same direction and side by side; a polarized light conversion sheet is arranged on the light output side of the microlens array, and the polarized light conversion sheet is provided with coatings arranged at equal intervals to form a polarized light conversion area with phase delay characteristics. and the unactivated light-transmitting area, wherein the polarization conversion area and the light-transmitting area are respectively aligned with the lens units in the microlens array, and a group of polarization conversion areas and light-transmitting areas each occupy half of the area of a lens unit; when light After passing through the polarizing conversion sheet, all polarized light of the same nature is formed for the display of the liquid crystal display; since there is no diffuser, it can increase the transmittance of the liquid crystal display (the general specification is 5%) by 1.3-2 times, Get stronger effective light.

The present invention has the following advantages:

1. Since the present invention does not use the traditional diffuser design, the light source is not consumed in large quantities, so the brightness can be improved and energy can be saved.

2. Since the present invention first projects light with a white light source group, and uses a polarized birefringent sheet to divide the incident non-polarized collimated light into P polarized light and S polarized light, and emits them from different angles; and after The microlens array and polarizing conversion film split and correspond to the liquid crystal display. It is measured that the transmittance of the liquid crystal display (general specification 5%) can be increased by 1.3-2 times, and stronger effective light can be obtained.

3. The present invention can be implemented by placing a powerful white LED light source on the optical axis, which is simpler and more practical than the prior art, and saves costs.

In order to facilitate the understanding of those skilled in the art, the present invention will be further described below in conjunction with the embodiments and accompanying drawings, and the contents mentioned in the implementation modes are not intended to limit the present invention.

A high-efficiency head-up display lighting system using a polarized light converter, as shown in Figure 1 and Figure 2, includes:

A light-emitting unit 10 is a white light diode (LED) that emits strong light, and can emit strong light L to the front; as shown in Figures 1 and 2, the light-emitting unit 10 is a single light source. As shown in Figure 6, the light-emitting unit 10 can also be a plurality of light-emitting diodes; in order to make the light rays parallel to the front, one or more collimating lenses 11 can be arranged in front of the light-emitting unit 10. 11 The number of optical components can be increased according to actual needs. In order to take into account the requirements of performance and space-saving, one or two are commonly used in design, but only one is shown in the drawings of this embodiment.

A polarizing birefringent sheet 20, used to receive the incident light L from the light emitting unit 10 and the collimating lens 11, and divide the incident non-polarized collimated light L into P polarized light and S polarized light Lp, Ls , and shoot at different angles respectively.

A group of microlens arrays 30 are used to receive the incoming P polarized light and S polarized light. The provided lens array surfaces 31, 32 are respectively formed with several continuous and closely arranged lens units 310, 320 on the lens array surfaces 31, 32; as shown in Figure 2, the lens units 310, 320 are a plurality of closely arranged square units; The two lens array surfaces 31, 32 of the microlens array 30 are provided with a light-transmitting material, so that the light Lp, Ls can directly pass through; and the microlens array 30 can be integrally formed by a transparent material, which will be more convenient in manufacture and assembly. ; As shown in Fig. 1 and Fig. 2, two lens array surfaces 31,32 of the microlens array 30 are based on the lens unit 310,320, and are in the state of facing each other, and the lens unit 310 can gather light Lp, Ls, and project On the lens unit 320 corresponding to the lens array surface 32, the direction of each light beam is changed by the lens unit 320, so that the P polarized light and the S polarized light are emitted in the same direction and side by side in a symmetrical manner

As shown in Figures 1-3, a polarization conversion sheet 40 is arranged on the light-emitting side of the microlens array 30, and the polarization conversion sheet 40 is provided with coatings arranged at equal intervals, thereby forming a polarization conversion region 41 and a phase delay characteristic. The light-transmitting region 42 without phase retardation. The polarization conversion area 41 and the light transmission area 42 are aligned with the lens units 310, 320 in the microlens array 30, and a group of polarization conversion areas 41 and the light transmission area 42 are respectively aligned with half of the area of each lens unit 310, 320 in the microlens array 30 ; and the coating of the polarization conversion region 41 has half-wave phase retardation (half-wave plate) characteristics, and the phase delay axis of the coating and the electric field polarization direction of the polarized light form an angle of 45 degrees or 135 degrees.

As shown in Fig. 1 and Fig. 2, in the present invention, the powerful light L emitted by the light-emitting unit 10 is radiated forward, and the collimating lens 11 enables the light to be emitted parallel to the front. , the incident non-polarized collimated light L is divided into P polarized light and S polarized light Lp, Ls. When the two polarized light Lp, Ls enter the microlens array 30, they first enter the first lens array The lens unit 310 on the surface 31, the light rays Lp and Ls of the P polarized light and the S polarized light are collected and refracted by the lens unit 310, and enter the lens unit 320 of the second lens array surface 32 in a left-right cross-symmetrical manner. The unit 320 can change the direction of each light beam, so that the P polarized light and the S polarized light are emitted in the same direction and side by side in a symmetrical manner; Region 42 corresponds, so when the first kind of polarized light Ls enters the lens unit 320, it enters the light-transmitting region 42 of the polarization conversion sheet 40, and then enters the liquid crystal display 50; while the second kind of polarized light Lp enters the lens unit After 320, it enters the polarization conversion region 41 of the polarization conversion sheet 40, converts the original polarized light Lp into another kind of polarized light Ls, and then enters the liquid crystal display 50; then all emitted light can become The S polarized light Ls of the same nature is used for displaying by the liquid crystal display 50 .

A collimator lens 20 is provided in front of the light emitting unit 10, and the collimator lens 20 can be a single lens group (comprising one or a plurality of optical elements), or a lens array composed of a plurality of collimator lenses, so that they are closely arranged side by side to form a A wide lighting surface. However, this is well known to those skilled in the art and is easy to implement, so it will not be repeated with the drawings; as shown in Figures 1 and 2, when considering space or material factors, the microlens array 30 can be implemented as shown in Figure 4 As an example, the microlens array 30 is equivalently replaced by a microlens array 30' composed of two half-blocks 31A, 32A with a lens unit 310, 320, and the two half-blocks 31A, 32A are pairwise symmetrical. The lens arrays protrude from the outside respectively to form several continuous and closely arranged lens units 310, 320; the lens units 310, 320 are aligned to achieve the same effect.

As shown in Figure 2, the lens units 310, 320 on the front lens array surface 31 and the rear lens array surface 32 of the microlens array 30 are a plurality of rectangular lenses, which can collect an appropriate amount of light and project it on the polarization conversion region 41 or the polarization conversion area 40 of the polarization conversion sheet 40. On the position of the light-transmitting region 42; under the premise that the light-emitting unit 10, the collimating lens 11, the polarized light birefringent sheet 20, and the polarized light conversion sheet 40 are all unchanged, the microlens array 30 can be designed as shown in Figure 5 The microlens array 30', the lens units 310', 320' on the front lens array surface 31' and the rear lens array surface 32' of the microlens array 30' are elongated cylindrical lenses, corresponding to the polarized light of the polarized light conversion sheet 40 The position of the conversion area 41 or the light transmission area 42 can achieve the desired effect.

As shown in Figure 6, the present invention can arrange light sources side by side to form densely distributed light sources for projection, and cooperate with one or more collimating lenses 11 to reduce the thickness of the lighting system, thereby improving the transmittance of the liquid crystal display (general specification 5 %) 1.3-2 times, to get a stronger effective light lighting system.

The traditional polarized light converter used in the projector system requires a plane mirror and a reflective polarized beam splitter to polarize the incident non-polarized light. Therefore, it is necessary to set and adjust the reflection angle, which is cumbersome to operate and is not conducive to production and application. . Moreover, due to the existence of the reflection angle, the device is bulky and takes up space resources, which is not conducive to use. However, the present invention uses a polarized birefringent sheet instead of a diffuser, and the light can penetrate the polarized birefringent sheet and be divided into P polarized light and S polarized light, which are emitted at different angles and pass through a group of microlenses. The role of the array and the polarizing conversion film is to form all the light into polarized light of the same nature, and then guide it into the liquid crystal display for display, which can reduce the loss of light, obtain an excellent and high-efficiency light source, and greatly reduce the space volume of the device . The polarization conversion area of the present invention is arranged on the outside of the polarization conversion sheet, and the entire polarization conversion sheet is treated with light transmission, which is convenient for production and processing.

The above content is only a preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. limits.

Claims (9)

1. a kind of high efficiency head up display lighting system using polar biased photoconverter, which is characterized in that including：

An at least luminescence unit, the strength light directive front that can will be sent out；And the front of luminescence unit is equipped with collimation lens；

One polar biased light birefringent plate, for receiving light by luminescence unit and collimation lens incidence, and by the non-polarization of incidence Collimated ray is divided into the light of P polar biased light and S polar biased light, and two light are projected with different angle respectively；

One group of microlens array, for receiving incident P polar biased light and S polar biased light；The microlens array is transparent cake knot Structure body, the incidence surface of microlens array and light-emitting surface are in being mutually parallel, and incidence surface and light-emitting surface are equipped with opposite saturating in position Lens array face；The lens array face is equipped with multiple continuous and compact arranged lens unit, so that P polar biased light and S polar biased light Optically focused and refraction of the light through first lens unit, symmetrically enter each phase in second lens array face in cross Corresponding lens unit, and the lens unit in second lens array face changes the direction of light beam, so that P polar biased light and S polar biased Light is projected with equidirectional and side-by-side configuration；

One polarisation dress changes piece, is set to the light emission side of lens array；The polarisation dress changes piece and is equipped with coating arranged at equal interval, with structure At with phase-delay characteristic polarisation transition zone and without the transparent area of phase-delay characteristic；The polarisation transition zone and thoroughly Light area is aligned with the lens unit in microlens array, and one group of polarisation transition zone and transparent area respectively account for a lens unit face Long-pending half；

Light is respectively formed the polar biased light of same nature after polarisation conversion sheet, is imaged with liquid crystal display.

2. a kind of high efficiency head up display lighting system using polar biased photoconverter according to claim 1, special Sign is, the lens unit is long cylindroid lens, and with the position phase of the polarisation transition zone of polarisation conversion sheet and transparent area It is right.

3. a kind of high efficiency head up display lighting system using polar biased photoconverter according to claim 1, special Sign is that the microlens array is an integral molding structure.

4. a kind of high efficiency head up display lighting system using polar biased photoconverter according to claim 1, special Sign is that the microlens array is made of two pieces of half blocks with lens unit；Two and half block is symmetrical block Shape lens, and the lens unit to form multiple continuous and close-packed arrays and be mutually aligned is protruded in the outside of two halves block.

5. a kind of high efficiency head up display lighting system using polar biased photoconverter according to claim 1, special Sign is that the luminescence unit is single light source, and the collimation lens is only one group.

6. a kind of high efficiency head up display lighting system using polar biased photoconverter according to claim 1, special Sign is that the collimation lens is the array of a plurality of optical elements composition.

7. a kind of high efficiency head up display lighting system using polar biased photoconverter according to claim 1, special Sign is, the luminescence unit at least two.

8. a kind of high efficiency head up display lighting system using polar biased photoconverter according to claim 1, special Sign is that the luminescence unit is light-emitting diode.

9. a kind of high efficiency head up display lighting system using polar biased photoconverter according to claim 1, special Sign is that the polarisation transition zone in the polarisation conversion sheet has half-wave phase lag characteristic, and the phase of polarisation conversion sheet is prolonged The electric field polarization direction of slow axis and polar biased light is in 45 degree.