CN104180269B - Automobile headlamp optical system - Google Patents

Abstract

The invention provides an automobile headlamp optical system which comprises an LED light source, a reflection part and a lens. The reflection part comprises a first reflecting mirror, a reflecting plate, a baffle and a second reflecting mirror. The first reflecting mirror comprises a first main reflecting mirror body and a first auxiliary reflecting mirror body. The portion, on the rear of the baffle, of the reflecting plate is used for reflecting some light shielded by the baffle to the lens secondarily so that a dipped headlight light type with light and shade cut-off lines can be obtained. The first reflecting mirror is shaped like an ellipsoid. The LED light source and an optical axis are vertically arranged on a first focal point of the ellipsoid. The first reflecting mirror is the upper half portion of the ellipsoid and extends to a second focal point. The baffle is arranged on the portion, located on the second focal point of the first reflecting mirror, of the ellipsoid. The portion, on the top of the baffle, of the reflecting plate reflects some light shielded by the baffle to the lens secondarily so that a dipped headlight light type with light and shade cut-off lines can be obtained; meanwhile, most of the light shielded and filtered out is fully utilized, and the utilization rate of luminous flux is increased.

Description

A kind of vehicle front lighting lamp optical system

Technical field

The present invention relates to field of LED illumination, especially a kind of vehicle front lighting lamp optical system.

Background technology

Existing LED automobile lower beam headlamp is used mostly projector structure, such as Chinese utility model patent (CN201561349U) a kind of vehicle front lighting dipped headlights disclosed in, its luminescence unit is superimposed with radiator, and each lights Unit is made up of reflector 7, baffle plate 5, lens 2 and light source 10, and its operation principle is：The light that reflector 7 sends LED light source 10 Converged, Jing baffle plates 5 shelter from some light to form "cut-off"line, light is obtained with bright again Jing after the convergence of lens 2 The dipped headlights light type of dark dead line；The shortcoming that this lower beam headlamp is present mainly has：1. light is by the eclipsing loss of baffle plate 5, LED The utilization rate of the light that light source 10 sends is relatively low, i.e. the utilization rate of luminous flux of light source is relatively low；2. the reflecting surface institute of the distal end of reflector 7 The light of reflection, reflexes to which direction reflects emitted light angle all more than 12 ° through lens 2, and this part light Line calculates the scope that (0.75/tan12 °=3.5) recent photograph is mapped within light fixture 3.5m by light fixture away from ground level 0.75m, And this some light is do not have not in all senses in driving, therefore this some light is also belonging to what is wasted.Therefore it is this near The irradiation distance of the light of light headlamp relatively near, light narrower width, light dark.

The content of the invention

The technical problem to be solved is to provide a kind of vehicle front lighting lamp optical system, meets car headlamp phase Close on the premise of requiring, the distance that light irradiates is farther, width increases, brightness is higher.

To solve above-mentioned technical problem, the technical scheme is that：A kind of vehicle front lighting lamp optical system, including LED Light source, reflecting part and lens, the reflecting part include be located at LED light source above the first reflecting mirror, positioned at first reflection Reflecting plate below mirror, the baffle plate in front of reflecting plate and before baffle plate lower section the second reflecting mirror；Described first is anti- Penetrating mirror includes LED light source light collection to reflex to the first principal reflection mirror of lens and LED light source light collection is reflexed to Second reflecting mirror further reflexes to the first auxiliary reflecting mirror of lens；By the reflecting plate at baffle plate rear the part blocked by baffle plate Light secondary reflects to lens, to obtain the dipped headlights light type with "cut-off"line；

First reflecting mirror is in elliposoidal, and the LED light source is arranged on the first of ellipsoid in the mode vertical with optical axis Focal point, first reflecting mirror is for elliposoidal top half and by the second focal point；

In the second focal point of the reflecting mirror of elliposoidal first, the baffle plate left side is horizontal straight line to the baffle plate setting, Right side is a broken line of the oblique line at 45 ° to horizontal line away from 25cm steering horizontals upwards.

The present invention secondary reflects to lens by the reflecting plate at the top of baffle plate some light blocked by baffle plate, to obtain Dipped headlights light type with "cut-off"line, while the most of light for filtering that is blocked is fully used, the profit of luminous flux It is improved with rate, and light distribution effect is substantially improved so that the irradiation distance of light, width is significantly increased；It is auxiliary by first Reflecting mirror and the cooperation of the second reflecting mirror secondary reflect to lens bottom front the light of reflecting mirror front end, strengthen the light of light Brightness simultaneously forms the illumination in IIIth area.

As improvement, the free curve design method of the lens：

The light type of automobile dipped headlight can be divided into four regions first area, second area, the 3rd region, the 4th region, There is corresponding illumination requirement value in each region, and the 3rd region is glare area, and its maximal illumination is being designed no more than 0.7lux The light sent from the focus of ellipsoid second is divided into into three parts according to angle during free-form surface lens and projects filament shield respectively Other three regions in addition to the 3rd region on curtain, can thus form specific light distribution situation；

After region division, the energy that can be set up after the reflecting mirror of ellipsoid first according to law of conservation of energy with It is irradiated to the relational equation of the energy of photometric screen：

If given light distribution is P₀, the central light strength of light source is I₀, it is considered to direction is θ₁The light photometric screen that incides Position is r₁, with axis angle θ is less than₁The incident position coordinateses of light again smaller than r₁, by Part I light θ₁I parts are divided into, Corresponding each θ₁In radius r₁On all divide into i parts, thus obtained array θ₁(i) and r₁(i), then first area goes out The preservation of energy expression formula of the illumination penetrated on light and screen is：

Angle is θ₁~θ₂Between light incide photometric screen position be r₁~r₂, this some light is divided into into j Part, correspond to each angle and divide into j parts on a radius, then the preservation of energy expression formula of the illumination on emergent light and screen For：

In the same manner, can obtain the 3rd region energy conservation expression formula is：

By these three expression formulas, the relational expression that can be respectively obtained between each zone radius and emergent light angle is as follows：

According to the characteristic of the reflecting mirror of ellipsoid first, in first the first focus of reflecting mirror, light will be from first for light source position Second focal point of reflecting mirror is projected, thus can regard the light of the second focus outgoing as a point source outgoing, with ellipsoid the Second focus of one reflecting mirror sets up coordinate system for origin, arranges rear cut-off distance f=15mm of lens, and free-form surface lens have two Face, the first face is a cylinder, and the second face is free form surface, and in the first face the law of refraction is applied：

During light is from air incidence to free form surface medium, the refractive index of air is n=1, and free-form surface lens are used Material PC makes, refractive index n=1.591, first refractive point A point coordinates value can try to achieve for (ftan (θ), f), and refracted light The slope value of AB is cot (θ '), and the linear equation of AB is obtained using point slope form；

Light is reflected when through the second face of free-form surface lens, and the vector form of the law of refraction is represented by：

Wherein：N is free form surface medium refraction index,For incident ray unit vector,For emergent ray unit to Amount,For free form surface light incidence point unit normal vector；Calculate the second face face type when, it is first determined one calculating Initial point, if it is (x, z) that light incides the point B coordinates on free form surface after the refraction of the first face, light is rolled over through lens The point C coordinates projected after penetrating on screen are (r, H), and wherein H=25m, r are according to law of conservation of energy by formula (7), (8), (9) Determine；Then, the unit vector of incident ray AB and emergent ray BC can be tried to achieve, and recycle law of refraction formula (11) to obtain To the normal vector of B points, so that it is determined that the incisal plane of the point, the incisal plane is incided with subsequent point after the refraction of the first face Ray intersection on free form surface is so that it is determined that the subsequent point of free form surface；Incisal plane and the normal vector of subsequent point by former point The straight line intersection at place obtains subsequent point, the coordinate of each point is obtained by computer iterations, so that it is determined that free form surface On each point coordinate.

The beneficial effect brought compared with prior art of the present invention is：

The present invention secondary reflects to lens by the reflecting plate at the top of baffle plate some light blocked by baffle plate, to obtain Dipped headlights light type with "cut-off"line, while the most of light for filtering that is blocked is fully used, the profit of luminous flux It is improved with rate, and light distribution effect is substantially improved so that the irradiation distance of light, width is significantly increased；It is auxiliary by first Reflecting mirror and the cooperation of the second reflecting mirror secondary reflect to lens bottom front the light of reflecting mirror front end, strengthen the light of light Brightness simultaneously forms the illumination in IIIth area.

Description of the drawings

Fig. 1 is schematic structural view of the invention.

Fig. 2 is decomposition view of the present invention.

Fig. 3 is cross-sectional view of the present invention.

Fig. 4 is light scattergram.

Fig. 5 is free-form surface lens design diagram.

Specific embodiment

With reference to Figure of description, the invention will be further described.

As shown in Figures 1 to 3, a kind of vehicle front lighting lamp optical system, including LED light source 5, reflecting part and lens 3, it is described Reflecting part includes being located at the first reflecting mirror 1 of the top of LED light source 5, the reflecting plate 4 below the first reflecting mirror 1, is located at The baffle plate 2 in the front of reflecting plate 4 and the second reflecting mirror 6 positioned at the above lower section of baffle plate 2；First reflecting mirror 1 is included LED light The light collection of source 5 reflexes to the first principal reflection mirror 11 of lens 3 and the light collection of LED light source 5 is reflexed to the second reflecting mirror 6 Further reflex to the first auxiliary reflecting mirror 12 of lens 3；By the reflecting plate 4 at the rear of baffle plate 2 some light blocked by baffle plate 2 Lens 3 are secondary reflected to, to obtain the dipped headlights light type with "cut-off"line.

First reflecting mirror 1 is in elliposoidal, and oval equation is：

a²-b²=c² (2)

-a≤z≤c,y≥0 (3)

In formula, a and b is oval long and short semiaxis, and c is distance of the focus to zero, by the elliptic curve along bus 180 ° of rotation.Ellipsoid has two focuses, and LED light source is placed on into the first focus of ellipsoid in the mode vertical with optical axis Place, the light that light source sends is assembled after reflection in the second focal point.Because LED light source approximate Lambertian body lights, thus it is ellipse 1 need of the first reflecting mirror of ball take top half and by it by the second focal point.

Require that on 25 meters of photometric screen, dipped beam should produce obvious "cut-off"line, its level according to international standard Part be located at v-v lines left side, right side is the oblique line with 15 ° on horizontal alignment, or upwards oblique line at 45 ° to horizontal line away from The broken line of 25cm steering horizontals.In order to form clearly "cut-off"line, baffle plate 2 should be placed on the first reflecting mirror of ellipsoid 1 Second focal point.The left side of the design baffle plate 2 is horizontal straight line, right side be one upwards oblique line at 45 ° to horizontal line away from The broken line of 25cm steering horizontals, and design with base integrated.

The free curve design method of the lens 3：

The light type of automobile dipped headlight can be divided into four regions first area, second area, the 3rd region, the 4th region, There is corresponding illumination requirement value in each region, and the 3rd region is glare area, and its maximal illumination is being designed no more than 0.7lux The light sent from the focus of ellipsoid second is divided into into three parts according to angle during free-form surface lens 3 and projects filament shield respectively Other three regions in addition to the 3rd region on curtain, as shown in figure 4, specific light distribution situation can be thus formed, Wherein O points are the focus of ellipsoid second.

After region division, according to the energy that law of conservation of energy can be set up after the first reflecting mirror of ellipsoid 1 With the relational equation of the energy for being irradiated to photometric screen：

If given light distribution is P₀, the central light strength of light source is I₀, it is considered to direction is θ₁The light photometric screen that incides Position is r₁, with axis angle θ is less than₁The incident position coordinateses of light again smaller than r₁, by Part I light θ₁I parts are divided into, Corresponding each θ₁In radius r₁On all divide into i parts, thus obtained array θ₁(i) and r₁(i), then first area goes out The preservation of energy expression formula of the illumination penetrated on light and screen is：

Angle is θ₁~θ₂Between light incide photometric screen position be r₁~r₂, this some light is divided into into j Part, correspond to each angle and divide into j parts on a radius, then the preservation of energy expression formula of the illumination on emergent light and screen For：

In the same manner, can obtain the 3rd region energy conservation expression formula is：

By these three expression formulas, the relational expression that can be respectively obtained between each zone radius and emergent light angle is as follows：

According to the characteristic of the first reflecting mirror of ellipsoid 1, in the first 1 first focus of reflecting mirror, light will be from for light source position Second focal point of one reflecting mirror 1 is projected, thus can regard the light of the second focus outgoing as a point source outgoing；Such as Fig. 5 It is shown, coordinate system is set up by origin of the second focus of the first reflecting mirror of ellipsoid 1, rear cut-off distance f=15mm of lens 3 is set, from There are two faces by toroidal lenss 3, the first face is a cylinder, and the second face is free form surface, and in the first face the law of refraction is applied：

During light is from air incidence to free form surface medium, the refractive index of air is n=1, and free-form surface lens 3 are used Material PC makes, refractive index n=1.591, first refractive point A point coordinates value can try to achieve for (ftan (θ), f), and refracted light The slope value of AB is cot (θ '), and the linear equation of AB is obtained using point slope form；

Light is reflected when through 3 second face of free-form surface lens, and the vector form of the law of refraction is represented by：

Wherein：N is free form surface medium refraction index,For incident ray unit vector,For emergent ray unit to Amount,For free form surface light incidence point unit normal vector；Calculate the second face face type when, it is first determined one calculating Initial point, if the point B coordinates that light is incided on free form surface after the refraction of the first face are (x, z), light is through the folding of lens 3 The point C coordinates projected after penetrating on screen are (r, H), and wherein H=25m, r are according to law of conservation of energy by formula (7), (8), (9) Determine；Then, the unit vector of incident ray AB and emergent ray BC can be tried to achieve, and recycle law of refraction formula (11) to obtain To the normal vector of B points, so that it is determined that the incisal plane of the point, the incisal plane is incided with subsequent point after the refraction of the first face Ray intersection on free form surface is so that it is determined that the subsequent point of free form surface；Incisal plane and the normal vector of subsequent point by former point The straight line intersection at place obtains subsequent point, the coordinate of each point is obtained by computer iterations, so that it is determined that free form surface On each point coordinate.

Claims (1)

1. a kind of vehicle front lighting lamp optical system, including LED light source, reflecting part and lens, it is characterised in that：The reflecting part Point include being located at the first reflecting mirror above LED light source, the reflecting plate below the first reflecting mirror, in front of reflecting plate Baffle plate and before baffle plate lower section the second reflecting mirror；First reflecting mirror includes LED light source light collection to reflex to First principal reflection mirror of lens and LED light source light collection is reflexed to the second reflecting mirror and then the first auxiliary of lens is reflexed to Reflecting mirror；Lens are secondary reflected to some light blocked by baffle plate by the reflecting plate at baffle plate rear, to obtain with bright The dipped headlights light type of dark dead line；

First reflecting mirror is in elliposoidal, and the LED light source is arranged on the first focus of ellipsoid in the mode vertical with optical axis Place, first reflecting mirror is for elliposoidal top half and by the second focal point；

The baffle plate setting, in the second focal point of the reflecting mirror of elliposoidal first, is horizontal straight line on the left of the baffle plate, right side For a broken line of the oblique line at 45 ° to horizontal line away from 25cm steering horizontals upwards；

The free curve design method of the lens：

The light type of automobile dipped headlight can be divided into four regions, first area, second area, the 3rd region, the 4th region, each There is corresponding illumination requirement value in region, and the 3rd region is glare area, and its maximal illumination is free in design no more than 0.7lux The light sent from the focus of ellipsoid second is divided into into three parts according to angle during toroidal lenss to project respectively on photometric screen Other three regions in addition to the 3rd region, can thus form specific light distribution situation；

After region division, the energy that can be set up after the reflecting mirror of ellipsoid first according to law of conservation of energy and irradiation To the relational equation of the energy of photometric screen：

If given light distribution is P₀, the central light strength of light source is I₀, it is considered to LED light source normal orientation angle it is θ₁Light The photometric screen that the light in direction is incided is r away from LED light source normal orientation distance₁Position, with axis angle be less than θ₁Light enter The position coordinateses penetrated are again smaller than r₁, by Part I light θ₁I parts are divided into, each θ is corresponded to₁It is r in distance₁Position on I parts are all divide into, array θ has thus been obtained₁(i) and r₁(i), then the energy of the illumination on first area emergent light and screen Measuring conservation expression formula is：

$2\mathrm{\π}{\∫}_0^{{\mathrm{\θ}}_1\left(i\right)}{I}_{0}cos\mathrm{\θ}sin\mathrm{\θ}\·d\mathrm{\θ}=2\mathrm{\π}{\∫}_0^{r_1\left(i\right)}{P}_0\·r\·dr---\left(1\right)$

Angle is θ₁~θ₂Between light incide photometric screen distance be r₁~r₂Position, this some light is divided into J parts, correspond to each angle and divide into j parts on a radius, then the preservation of energy expression formula of the illumination on emergent light and screen For：

$2\mathrm{\π}{\∫}_{{\mathrm{\θ}}_1}^{{\mathrm{\θ}}_2\left(j\right)}{I}_{0}cos\mathrm{\θ}sin\mathrm{\θ}\·d\mathrm{\θ}=2\mathrm{\π}{\∫}_{r_1}^{r_2\left(j\right)}{P}_0\·r\·dr---\left(2\right)$

In the same manner, can obtain the 3rd region energy conservation expression formula is：

$2\mathrm{\π}{\∫}_{{\mathrm{\θ}}_2}^{{\mathrm{\θ}}_3\left(k\right)}{I}_{0}cos\mathrm{\θ}sin\mathrm{\θ}\·d\mathrm{\θ}=2\mathrm{\π}{\∫}_{r_2}^{r_3\left(k\right)}{P}_0\·r\·dr---\left(3\right)$

By these three expression formulas, the relational expression that can be respectively obtained between each zone radius and emergent light angle is as follows：

$r_1\left(i\right)=\sqrt{\frac{I_0}{P_0}\·{\sin }^2{\mathrm{\θ}}_1\left(i\right)}---\left(4\right)$

$r_2\left(j\right)=\sqrt{\frac{I_0}{P_0}\·\left({\sin }^2{\mathrm{\θ}}_2\right(j)-{\sin }^2{\mathrm{\θ}}_1)+r_1^2}---\left(5\right)$

$r_3\left(k\right)=\sqrt{\frac{I_0}{P_0}\·\left({\sin }^2{\mathrm{\θ}}_3\right(k)-{\sin }^2{\mathrm{\θ}}_2)+r_2^2}---\left(6\right)$

According to the characteristic of the reflecting mirror of ellipsoid first, in first the first focus of reflecting mirror, light will be from the first reflection for light source position Second focal point of mirror is projected, thus can regard the light of the second focus outgoing as a point source outgoing, anti-with ellipsoid first The second focus for penetrating mirror sets up coordinate system for origin, arranges rear cut-off distance f=15mm of lens, and free-form surface lens have two faces, First face is a cylinder, and the second face is free form surface, and in the first face the law of refraction is applied：

$\frac{sin\mathrm{\θ}}{{\mathrm{sin\θ}}^{\′}}=\frac{n^{\′}}{n}---\left(7\right)$

During light is from air incidence to free form surface medium, the refractive index of air is n=1, and free-form surface lens use material PC makes, refractive index n'=1.591, first refractive point A point coordinates value can try to achieve for (ftan (θ), f), and refracted light AB Slope value be cot (θ '), the linear equation of AB is obtained using point slope form；

Light is reflected when through the second face of free-form surface lens, and the vector form of the law of refraction is represented by：

Wherein：N is free form surface medium refraction index,For incident ray unit vector,For emergent ray unit vector, For free form surface light incidence point unit normal vector；Calculate the second face face type when, it is first determined one calculating it is initial Point, if it is (x, z) that light incides the point B coordinates on free form surface after the refraction of the first face, light is after lens refraction The point C coordinates projected on screen are (r, H), and wherein H=25m, r are determined according to law of conservation of energy by formula (4), (5), (6)； Then, the unit vector of incident ray AB and emergent ray BC can be tried to achieve, and recycle law of refraction formula (8) that B points are obtained Normal vector, so that it is determined that the incisal plane of the point, freedom is incided in the incisal plane with subsequent point after the refraction of the first face Ray intersection on curved surface is so that it is determined that the subsequent point of free form surface；It is located with the normal vector of subsequent point by the incisal plane of former point Straight line intersection obtain subsequent point, by computer iterations the coordinate of each point is obtained, so that it is determined that on free form surface The coordinate of each point；

R is distance of the light irradiation position away from LED light source normal orientation, and θ is light and the angle of LED light source normal orientation, θ₁ I () is by angle, θ₁The angle of i-th part of correspondence light and LED light source normal orientation, r after decile₁I () is and LED light source normal direction side It is θ to angle₁The light irradiation position of (i) and the distance of LED light source normal orientation, θ₂J () is by angle, θ₂Jth part after decile The angle of correspondence light and LED light source normal orientation, r₂J it with LED light source normal orientation angle is θ that () is₂The light irradiation of (j) Position and the distance of LED light source normal orientation, θ₃K () is by angle, θ₃Kth part correspondence light and LED light source normal direction side after decile To angle, r₃K it with LED light source normal orientation angle is θ that () is₃The light irradiation position of (k) and LED light source normal orientation Distance, k is represented Part III light θ₃Kth part after decile, n' represents the refractive index of lens, and θ ' represents light through lens After refraction with incidence point at normal orientation angle, H represents the distance of LED light source distance objective shadow surface.