CN113823725B - Solving the spherical light source packaging method of headlights with short-range hollow beams - Google Patents

Abstract

The invention discloses a method for encapsulating a spherical light source of a headlamp that solves short-range hollow light beams. The headlamp includes a reflector, an LED light source, a circuit board, a power supply, and a lamp housing; the reflector is a rotating parabolic reflector, the light source is placed at the bottom, and the light directly emitted by the light source and the light reflected by the rotating paraboloid are emitted from the top opening; the light source at the bottom of the headlight reflector is arranged as a raised spherical light source. The solution proposed by the present invention is simple to operate, and the original light source can be directly replaced. The packaging process of the light source is easy to control, and the cost is low. It does not need to change the original reflector or add a lens. It can avoid the cost increase, absorption loss and color ring caused by secondary optical design and production, and has considerable application value.

Description

Solving the spherical light source packaging method of headlights with short-range hollow beams

This application is a divisional application with application number: 201910077837.9, application date: 2019.1.28, and title "Short-range hollow beam headlamp and its spherical light source packaging method".

technical field

The invention relates to a headlight and a spherical light source packaging method thereof.

Background technique

Headlights are widely used in lighting scenes such as coal mines and outdoor activities at night due to their small size and easy portability, and their main components are rotating paraboloids. The rotating paraboloid is a curved surface obtained by rotating a parabola around the axis of symmetry. Its characteristic is that the light emitted by the focal point will be emitted parallel to the axis of the paraboloid after being reflected by the paraboloid. If a large-angle light source is placed at the focal point of the paraboloid, the reflected light will form a circular spot with uniform illumination on the receiving surface. The boundary of the spot is relatively clear and the irradiation distance is long. However, the rotating parabolic reflector is not a complete paraboloid, and the part from the focal plane to the apex of the paraboloid is cut off. Therefore, the LED light source placed at the focal point still has a certain distance from the bottom of the reflector, and the reflected parallel light cannot reach the center of the short-distance light screen, as shown in Figure 1. At the same time, the spatial solid angle β of the light that is not reflected by the reflector directly irradiates the center of the light screen is very small, which cannot provide sufficient illumination on the 25 cm target surface, so a dark spot appears at the center of the light screen at a short distance, making the light spot a bright ring.

This kind of problem makes it difficult to distinguish the details of objects when observing at close range, resulting in large operational errors and low precision. For example, operations such as tapping rubber at night are difficult to complete accurately. Chinese patent document CN101886783A Zhou Mingjie and others disclose a spotlight reflector, the inner surface of which is a paraboloid, and a uniform light spot is obtained by adjusting the parameters of the paraboloid, but the diameter of the open end of the reflector is 34-38 mm, resulting in a small light spot. At the same time, because the narrow end is only 4-6 mm, the length of the reflector is equivalent to the open diameter, which is not conducive to installation. Chinese patent document CN104834762A Chen Liang et al. disclose a COB-type LED reflector design method. The initial curved surface is generated by calculating the free-form surface data of the reflector, and the curved surface is dynamically divided. According to the simulation results, it is adjusted and optimized several times to finally obtain a uniform irradiated surface. However, the design process of the free-form surface lens is cumbersome, requires high processing accuracy, and is expensive. In addition, the method of adding a lens has absorption loss of light energy, and is prone to dispersion, resulting in a color ring in the light spot and affecting the lighting quality. This just urgently needs those skilled in the art to find the method that simply and effectively solves the short-range hollow beam problem of the headlamp.

Contents of the invention

The purpose of the present invention is to provide a headlamp and a spherical light source packaging method that can solve the problems of short-range hollow beams, which can avoid the problems of cost increase, absorption loss and color ring caused by secondary optical design and production.

Technical solution of the present invention is:

A headlight for short-range hollow light beams. The headlight includes a reflector, an LED light source, a circuit board, a power supply and a lamp housing; the reflector is a rotating parabolic reflector, a light source is placed at the bottom, and the light directly emitted by the light source and the light reflected by the rotating paraboloid are emitted from the top opening; the feature is that the light source at the bottom of the headlight reflector is set as a raised spherical light source.

The focal length of the rotating parabolic reflector is 6.5-7.5mm, the bottom opening radius is 12-18mm, and the top exit diameter is 70-75mm.

A method for encapsulating a spherical light source of a headlamp that solves short-range hollow beams is characterized in that it includes the following steps:

Step 1: Bond the LED chip to the center of a circular reflective concave platform with a diameter d of 2-4mm, and the inner height h of the concave platform is 0.1-0.3mm;

Step 2: Finally, use silica gel with a mixed viscosity range of 3500-7000 mPa·s to prepare a phosphor silica gel mixture in a ratio of 1:1:x, where 1:1 is the ratio of silica gel AB components, x is the mass of phosphor powder, 0.1 ≤ x ≤ 0.4, and pour the mixture on the chip surface until the mixture bulges;

Step 3: Put the lamp beads into the oven and bake at a temperature range of 148-153°C for 58-63 minutes, measure the height H from the upper surface of the chip to the apex of the phosphor bumps, the range of H: 0.8-1.2 mm,

Step 4: Cover the lens and inject potting glue inside, put the lamp beads in an oven with a temperature range of 78-83°C and bake for 30-33 minutes, then bake at a temperature range of 118-123°C for 30-35 minutes.

The solution proposed by the present invention is simple to operate, and can directly replace the original light source. The packaging process of the light source is easy to control, and the cost is low. It does not need to change the original reflector or add a lens. It can avoid the problems of cost increase, absorption loss and color ring caused by the secondary optical design and production, and has considerable application value.

Description of drawings

Figure 1 Schematic diagram of a dark spot appearing at the center of the light screen at a close distance from a point light source;

Fig. 2 is a schematic cross-sectional view of an existing headlight of Embodiment 1;

Fig. 3 is a schematic cross-sectional view of a headlamp with a raised spherical light source in Embodiment 1;

Figure 4 is a comparison diagram of short-distance and long-distance light spots before and after the replacement of the light source;

FIG. 5 is a schematic diagram of the light source package structure and the definitions of H and h in Embodiment 2. FIG.

1 raised spherical light source; 2 rotating parabolic reflector; 3 lamp housing; 4 circuit board; 5 LED light source; 11 lens; 12 potting glue; 13 powder mixing glue; 14 gold wire; 15 plastic outer frame;

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention, and the operating principles of the embodiments can be explained in conjunction with the relevant description of the content of the invention. With reference to these contents, those skilled in the art should be able to understand other possible implementations and features of the present invention. Components in the figures are not drawn to scale.

Embodiment: 1:

This embodiment proposes a solution for replacing the light source with the short-range hollow beam of the headlight. The existing headlight includes a rotating parabolic reflector 2, an LED light source 5, a circuit board 4 and a lamp housing 3, as shown in FIG. 2 . The light source 5 shown in FIG. 2 is a chip-type LED light source, but it is not limited thereto, and may also be other forms of light sources, such as COB light sources, high-power packaged planar light sources, and the like. The axis of the above-mentioned light source 5 coincides with the axis of the reflector 2, and the light-emitting surface of the LED chip is located in the focal plane of the rotating parabolic reflector 2, and the center coincides with the focus. This type of light source causes the light emitted by the headlamp to be a hollow beam at a short distance, which is manifested as a ring-shaped light spot on the short-distance receiving plane, with weak light intensity in the center and strong light intensity around it.

The headlight reflector is a rotating parabolic reflector with a small opening at the bottom to place the light source and a large opening at the top. The light directly emitted by the light source and the reflected light exit from the top. At the same time, the focal length of the rotating parabolic reflector is 7mm, the radius of the bottom opening is 15mm, the outlet diameter is 72.5mm, and the mirror reflection layer is coated inside.

The present invention replaces the light source 5 at the bottom of the existing headlight reflector with a raised spherical light source 1, as shown in FIG. 3 . The light source in Figure 3 is a raised spherical light source, and the light emitting surface is no longer a point or a plane, but a raised spherical surface. The divergence angle of the light source 1 is larger than that of the original light source 5, and it has a rich dispersion angle. After the large-angle diffuse light is reflected by the reflector 2, the outgoing light shifts to the center of the beam, which compensates for the central light intensity to a certain extent. The height H from the upper surface of the chip of the spherical light source 1 to the apex of the phosphor bumps is H. When the value of the height H is between 0.8-1.2 mm, the near-distance central light intensity is significantly improved; when H is 1.01 mm, the uniformity of the short-distance spot is increased from the previous 9.6% to the optimum value of 93.2%. Figure 4 is the comparison diagram of short-distance and long-distance light spots before and after the replacement of the light source, in which (a) and (b) are the light spot test pictures of the original light source at 25 cm and 3 m, respectively, and (c) and (d) are the test pictures of the spherical light source with H=1.01 mm convex at 25 cm and 3 m respectively. The test results show that the three-dimensional spherical convex light source can significantly improve the quality of short-distance spot, which meets the needs of close-distance observation. At the same time, it has no effect on the quality of the light spot at a distance of 3 meters.

Example 2:

The packaging method of the replacement light source 1 in the present invention has the following steps:

Step 1: As shown in FIG. 5 , bond the LED blue light chip 18 to the center of the supporting platform 17 of the bracket. The surface of the carrying platform 17 is concave, with a diameter of d=3mm and an inner height of h=0.2mm, which can be used as a metal heat sink at the same time. The positive and negative poles of the chip 18 are connected to the lead frame 16 with gold wires 14, and the chip 18 is an LED blue chip;

Step 2: Use silica gel with a mixed viscosity of 5000mPa·s to prepare a phosphor silica gel mixture at a mass ratio of 1:1:0.158 (where 1:1 is the ratio of the silica gel to AB components, and 0.158 is the mass of the phosphor powder), and pour the mixture on the surface of the chip until the mixture is raised, as shown in Figure 5. Filling glue 13;

Step 3: Put the lamp beads into the oven and bake at a temperature range of 150°C for 60 minutes, measure the height H from the upper surface of the chip to the apex of the phosphor bumps, the selection range is H=1.00-1.02 mm, and the definition of H is shown in Figure 5;

Step 4: Cover the lens 11 inside the plastic frame 15 and inject the potting glue 12 inside, put the lamp beads into an oven with a temperature range of 80°C and bake for 30 minutes, then bake at a temperature range of 120°C for 30 minutes, aging and testing, to make a raised spherical light source.

Although the present invention has been specifically shown and described in detail in conjunction with specific embodiments, those skilled in the art should understand that various changes can be made to the present invention in form and details without departing from the spirit and scope of the present invention defined by the appended claims, all of which are within the protection scope of the present invention.

Claims (1)

1. A spherical light source packaging method for solving the problem of a head lamp with a short-range hollow light beam is characterized in that: the headlight reflector for solving the short-range hollow light beam is a rotating parabolic reflector, a light source is placed, light directly emitted by the light source and reflected light are emitted from the top, meanwhile, the focal length of the rotating parabolic reflector is 7mm, the radius of an opening at the bottom is 15mm, the diameter of an outlet at the top is 72.5mm, and a specular reflection layer is internally plated;

the height H from the upper surface of the chip of the spherical light source to the top point of the fluorescent powder bulge is 1.01mm;

the packaging method comprises the following steps:

step 1: bonding an LED chip at the center of a circular reflecting concave table support with the diameter d of 2-4mm, wherein the height h of the inside of the concave table is 0.1-0.3mm;

step 2: after wire bonding, preparing a fluorescent powder silica gel mixture by adopting silica gel with the mixed viscosity range of 3500-7000 mPas according to the proportion of 1:1:x, wherein 1:1 is the proportion of the components AB of the silica gel, x is the mass of fluorescent powder, x is more than or equal to 0.1 and less than or equal to 0.4, and dispensing the mixture on the surface of a chip until the mixture protrudes;

step 3: the lamp beads are put into an oven to be baked for 58-63 minutes at the temperature ranging from 148-153 ℃, the height H from the upper surface of the chip to the top point of the fluorescent powder bulge is measured, the H is 1.01 and mm,

step 4: covering the lens, injecting pouring sealant into the lens, placing the lamp beads into a baking oven with the temperature range of 78-83 ℃ for baking for 30-33 minutes, and then baking for 30-35 minutes with the temperature range of 118-123 ℃.