TWI671915B - Light modulator and laser radar using the same - Google Patents

Abstract

The present invention provides a light modulator, including: a first light modulation section, the first light modulation section including a first substrate and a first transparent conductive layer and a first thermally conductive layer disposed on the first substrate; a second A light modulation section is disposed opposite to the first light modulation section, and the second light modulation section includes a second substrate and a second transparent conductive layer and a second thermally conductive layer provided on the second substrate. The two heat-conducting layers and the first heat-conducting layer are used for extracting heat generated when incident light passes through the light modulator; and a liquid crystal layer, the liquid crystal layer is disposed on the first light modulation section and the second Between the light modulation sections, the incident light is modulated by the deflection of liquid crystal molecules. The light modulator provided by the invention avoids the influence of the heat on the liquid crystal layer, destroys the liquid crystal properties, and is beneficial to improving the performance stability of the light modulator.

Description

Optical modulator and laser radar using the same

The present invention relates to an optical modulator and a laser radar using the same.

Laser radar has become an indispensable key sensor for unmanned driving. At present, the vehicle-mounted laser radars on the market are mainly mechanical laser radars and solid-state laser radars, but they all have the disadvantages of difficult optical path debugging, complicated assembly, long production cycle and high cost.

Therefore, based on the above-mentioned problems, the current novel solid-state laser radars mostly use a liquid crystal light modulator to modulate the laser emitted by the laser light source in the laser radar. However, since the light incident on the liquid crystal light modulator is a laser, and in the liquid crystal light modulator, an indium tin oxide (ITO) layer is generally arranged on both sides of the liquid crystal layer. Due to the absorption of laser light by ITO and poor heat dissipation of the glass, the local area of the liquid crystal layer has excessively high heat, which damages the original characteristics of the liquid crystal molecules in the liquid crystal layer, thereby affecting the function of the light modulator.

An aspect of the present invention provides a light modulator, including: a first light modulation section, the first light modulation section including a first substrate and a first transparent conductive layer and a first thermally conductive layer disposed on the first substrate; A second light modulation section is disposed opposite to the first light modulation section. The second light modulation section includes a second substrate and a second transparent conductive layer and a second thermally conductive layer provided on the second substrate. The second thermally conductive layer and the first thermally conductive layer are used to extract heat generated when incident light passes through the light modulator; and a liquid crystal layer, the liquid crystal layer is disposed on the first light modulation section and the Between the second light modulators, the incident light is modulated by the deflection of liquid crystal molecules.

Another aspect of the present invention provides a laser radar, comprising: a laser light source for emitting laser light; and An optical modulator is disposed on an emission path of the laser emitted from the laser light source, and the optical modulator is the optical modulator according to any one of claims 1-8.

The optical modulator provided in this embodiment uses the first transparent conductive layer and the second transparent conductive layer to radiate the heat of the laser absorbed by the first transparent conductive layer and the second transparent conductive layer, thereby avoiding the heat The liquid crystal layer affects and destroys the properties of liquid crystal molecules in the liquid crystal layer, which is beneficial to improving the performance stability of the light modulator.

100‧‧‧ light modulator

110‧‧‧First light modulation section

111‧‧‧first substrate

112‧‧‧The first transparent conductive layer

113‧‧‧first thermally conductive layer

1131‧‧‧First Hole

1132‧‧‧First metal layer

1133‧‧‧The first anodic oxide layer

114‧‧‧first orientation film

120‧‧‧Second light modulation section

121‧‧‧ second substrate

122‧‧‧Second transparent conductive layer

123‧‧‧second thermally conductive layer

1231‧‧‧Second Hole

1232‧‧‧Second metal layer

1233‧‧‧Second anodic oxide layer

124‧‧‧Second orientation film

130‧‧‧LCD layer

200‧‧‧laser radar

210‧‧‧laser light source

FIG. 1 is a schematic perspective view of a light modulator according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a light modulator provided in Embodiment 1 of the present invention.

FIG. 3 is a schematic structural diagram of states of a first hole and a second hole under different oxidation voltages according to an embodiment of the present invention.

FIG. 4 is a schematic structural diagram of states of a first hole and a second hole under different electrolyte concentrations provided by an embodiment of the present invention.

FIG. 5 is a schematic diagram of a change in current density with a reaction temperature according to an embodiment of the present invention.

FIG. 6 is a schematic cross-sectional structure diagram of an optical modulator provided in Embodiment 2 of the present invention.

FIG. 7 is a schematic diagram of a laser radar module according to an embodiment of the present invention.

Example one

Please refer to FIG. 1, a light modulator 100 provided in this embodiment includes a first light modulation section 110, a second light modulation section 120, and a liquid crystal layer 130. The first light modulation section 110 and the second light modulation section 120 are oppositely disposed, and the liquid crystal layer 130 is disposed between the first light modulation section 110 and the second light modulation section 120.

As shown in FIG. 2, the first light modulation section 110 includes a first substrate 111, a first transparent conductive layer 112 and a first thermally conductive layer 113 disposed on the first substrate 111.

The first transparent conductive layer 112 is formed of a transparent conductive material. In one embodiment, the first transparent conductive layer 112 is indium tin oxide (ITO).

As shown in FIG. 2, the first thermally conductive layer 113 includes a first metal layer 1132 and a first anodic oxide layer 1133 formed on the first metal layer 1132. The first anodic oxide layer 1133 is formed by anodizing a metal. A plurality of first holes 1131 are formed in the first anodic oxide layer 1133. The first hole 1131 is formed by the metal during anodization, and its specific shape and pore size are related to the process parameters (such as oxidation voltage, electrolyte concentration, etc.) of the anodization. The first hole 1131 enables the first anodic oxide layer 1133 to have a larger specific surface area, so that the first transparent conductive layer 112 has good heat dissipation performance. The metal may be aluminum, or an aluminum, magnesium aluminum, or stainless steel may be anodized. In this embodiment, the metal is aluminum, and the first anodic oxide layer 1133 is formed by anodizing aluminum.

The first thermally conductive layer 113 is formed on the surface of the first substrate 111 facing the second light modulation part 120, and the first transparent conductive layer 112 is directly formed on the surface of the first thermally conductive layer 113 away from the first substrate 111. The first thermally conductive layer The first anodic oxide layer 1133 of 113 is in direct contact with the first transparent conductive layer 112 to discharge the heat on the first transparent conductive layer 112.

Please continue to refer to FIG. 2, the second light modulation unit 120 includes a second substrate 121, and a second transparent conductive layer 122 and a second thermally conductive layer 123 disposed on the second substrate 121.

The second transparent conductive layer 122 is formed of a transparent conductive material. In one embodiment, the second transparent conductive layer 122 is indium tin oxide (ITO).

As shown in FIG. 2, the second thermally conductive layer 123 includes a second metal layer 1232 and a second anodic oxide layer 1233 formed on the second metal layer 1232. The second anodic oxide layer 1233 is formed by anodizing a metal. A plurality of second holes 1231 are formed in the second anodic oxide layer 1233. The second holes 1231 are formed by the metal during anodization. The specific shape and pore diameter of the second anodic oxide layer 1231 and the anodic oxidation process parameters (such as oxidation voltage, electrolyte concentration, etc. ) Related. The second hole 1231 makes the second anodic oxide layer 1233 have a large specific surface area, so that the second transparent conductive layer 122 has good heat dissipation performance. The metal may be aluminum, or an aluminum, magnesium aluminum, or stainless steel may be anodized. In this embodiment, the metal is aluminum, and the second anodic oxide layer 1233 is formed by anodizing aluminum.

The second thermally conductive layer 123 is formed on the surface of the second substrate 121 facing the first light modulation part 110, and the second transparent conductive layer 122 is directly formed on the surface of the second thermally conductive layer 123 away from the second substrate 121. The second thermally conductive layer The second anodic oxide layer 1233 of 123 is in direct contact with the second transparent conductive layer 122 to discharge the heat on the second transparent conductive layer 122.

In other embodiments, the metal forming the first thermally conductive layer 113 is completely oxidized during the anodizing process. At this time, the first thermally conductive layer 113 does not include the first metal layer 1132 and only includes the first anodic oxide layer 1133. Similarly, when the metal forming the second thermally conductive layer 123 is completely anodized, Partial oxidation. At this time, the second thermally conductive layer 123 does not include the second metal layer 1232, and only includes the second anodic oxide layer 1233.

Please refer to FIG. 2. In an embodiment, the light modulator 100 further includes a first alignment film 114 disposed between the first transparent conductive layer 112 and the liquid crystal layer 130, and a second transparent conductive layer 122 and the liquid crystal layer. The second alignment film 124, the first alignment film 114 and the second alignment film 124 are positioned between 130 to position an initial direction for the liquid crystal molecules in the liquid crystal layer 130.

The first alignment film 114 and the second alignment film 124 are doped with thermally conductive particles. In one embodiment, the thermally conductive particles are AlN (aluminum nitride), Graphene, BN, etc. The first alignment film 114 and the second alignment film 124 further improve the heat dissipation performance of the light modulator 100.

Referring to FIG. 3 to FIG. 5, in one embodiment, the depth and diameter of the first hole 1131 and the second hole 1231 can be adjusted by adjusting conditions such as the oxidation voltage of metal aluminum, the electrolyte concentration, and the reaction temperature. The reaction temperature mainly affects the current density in the oxidation process.

Fig. 3 shows the shapes of the first holes 1131 and the second holes 1231 formed under different oxidation voltages. Among them, the first holes formed when the voltages are 20V, 30V, 40V, and 50V are shown in Figs. A, b, c, and d, respectively. 1131 and the state of the second hole 1231.

Fig. 4 shows the shapes of the first holes 1131 and the second holes 1231 formed at different electrolyte concentrations. Among them, the figures shown in Figs. A, b, and c are 0.3 mol per liter, 0.5 mol per liter, and 1 The state of the first pores 1131 and the second pores 1231 formed when the oxalic acid concentration of Moore rises.

Figure 5 shows the change in current density with reaction temperature. The abscissa is the reaction temperature and the ordinate is the current density. It can be seen that when the reaction temperature is between 15 and 50 ° C, the current density increases with the reaction temperature. And get bigger.

The optical modulator 100 in this embodiment is configured to modulate incident light. The incident light is incident from the first light modulation part 110 and emitted from the second light modulation part 120. When no voltage is applied to the first conductive layer 112 and the second conductive layer 122, the liquid crystal molecules in the liquid crystal layer 130 are located in an initial direction, and the initial direction is determined by the arrangement of the first alignment film 114 and the second alignment film 124. . When a voltage is applied to the first conductive layer 112 and the second conductive layer 122, the liquid crystal molecules in the liquid crystal layer 130 are deflected. When the incident light passes through the liquid crystal layer 130 and exits from the second light modulation section 120, its phase changes. The above process completes the modulation of the incident light.

The optical modulator 100 provided in this embodiment emits the heat of the laser absorbed by the first transparent conductive layer 112 and the second transparent conductive layer 122 through the first transparent conductive layer 112 and the second transparent conductive layer 122. The influence of the heat on the liquid crystal layer 130 is avoided, the properties of the liquid crystal molecules in the liquid crystal layer 130 are destroyed, and the performance stability of the light modulator 100 is improved.

Example two

As shown in FIG. 6, the optical modulator 100 provided in this embodiment is described in this embodiment. Only the differences from the first embodiment will be described in detail, and the others will not be repeated.

In the optical modulator 100 in this embodiment, a first transparent conductive layer 112 is formed on a surface of the first substrate 111 facing the second light modulation part 120, and a first thermal conductive layer 113 is formed directly on the first transparent conductive layer 112 away from the first substrate. On the surface of 111, the first metal layer 1132 is in direct contact with the first transparent conductive 112 layer.

The second transparent conductive layer 122 is formed on the surface of the second substrate 121 facing the first light modulation part 110. The second thermal conductive layer 123 is directly formed on the surface of the second transparent conductive layer 122 away from the second substrate 121. The second metal layer 1232 and The second transparent conductive layer 122 is in direct contact.

The first alignment film 114 is disposed between the first transparent conductive layer 112 and the liquid crystal layer 130, the second alignment film 124 is disposed between the second transparent conductive layer 122 and the liquid crystal layer 130, and the first alignment film 114 and the second The alignment film 124 is used to position an initial direction for the liquid crystal molecules in the liquid crystal layer 130.

The working principle of the optical modulator 100 is similar to the description of the corresponding principle in the first embodiment, and is not repeated here.

It should be understood that the optical modulator 100 in this embodiment can achieve all the beneficial effects as described in the first embodiment.

Please refer to FIG. 7, this embodiment also provides a laser radar 200. The laser radar includes a laser light source 210 and a light modulator 100. The laser emitted by the laser light source 210 is modulated by the light modulator 100. The laser is emitted to the target object and reflected back to the laser radar 200, so that the target object can be measured. The optical modulator in this embodiment is as described above. The laser radar 200 provided in this embodiment can achieve all the beneficial effects of the optical modulator 100 described above.

The above is only an embodiment of the present invention, and does not limit the scope of the patent of the present invention. Any equivalent structure or equivalent process transformation made by using the description and drawings of the present invention, or directly or indirectly applied to other related technologies The fields are equally included in the patent protection scope of the present invention.

Claims (8)

An optical modulator is improved, comprising: a first light modulation section, the first light modulation section includes a first substrate, and a first transparent conductive layer and a first thermally conductive layer disposed on the first substrate; Two light modulation sections are disposed opposite to the first light modulation section. The second light modulation section includes a second substrate, and a second transparent conductive layer and a second thermally conductive layer provided on the second substrate. The second thermally conductive layer and the first thermally conductive layer are used to extract heat generated when incident light passes through the light modulator; and a liquid crystal layer, the liquid crystal layer is disposed on the first light modulation section and the first The two light modulation sections are configured to modulate the incident light by the deflection of liquid crystal molecules; the first thermally conductive layer includes a first metal layer and a first anodic oxide layer formed on a surface of the first metal layer. The second thermally conductive layer includes a second metal layer and a second anodic oxide layer formed on a surface of the second metal layer; a plurality of first holes are formed on the first anodic oxide layer, and the second anodic oxidation A plurality of second holes are formed in the material layer. The light modulator according to claim 1, wherein the first heat conductive layer is formed on a surface of the first substrate facing the second light modulation part, and the first transparent conductive layer is formed on the first The thermally conductive layer is far from the surface of the first substrate, and the first anodic oxide layer is in direct contact with the first transparent conductive layer; the second thermally conductive layer is formed on the second substrate toward the first light modulation The second transparent conductive layer is directly formed on the surface of the second thermally conductive layer away from the second substrate, and the second anodic oxide layer is in contact with the second transparent conductive layer. The light modulator according to claim 2, wherein each of the first holes and each of the second holes has an inner wall; the first transparent conductive layer further covers the first anodic oxide The inner walls of all the first holes in the layer, and the second transparent conductive layer also covers the inner walls of all the second holes in the second anodic oxide layer. The light modulator according to claim 1, wherein the first transparent conductive layer is formed on a surface of the first substrate facing the second light modulation section, and the first heat conductive layer is directly formed on the first A transparent conductive layer away from the surface of the first substrate, the first metal layer is in direct contact with the first transparent conductive layer; the second transparent conductive layer is formed on the second substrate toward the first light On the surface of the modulation part, the second thermally conductive layer is directly formed on a surface of the second transparent conductive layer away from the second substrate, and the second metal layer is in direct contact with the second transparent conductive layer. The light modulator according to claim 2, wherein the light modulator further comprises: a first alignment film, the first alignment film is disposed between the first transparent conductive layer and the liquid crystal layer And a second alignment film, which is disposed between the second transparent conductive layer and the liquid crystal layer; the first alignment film and the second alignment film are used for the liquid crystal The molecules are positioned in an initial direction. The light modulator according to claim 4, wherein the light modulator further comprises: a first alignment film, the first alignment film being disposed between the first thermally conductive layer and the liquid crystal layer; And a second alignment film, the second alignment film is disposed between the second thermally conductive layer and the liquid crystal layer; the first alignment film and the second alignment film are used for positioning the liquid crystal molecules An initial direction. The light modulator according to claim 5 or 6, wherein both the first alignment film and the second alignment film are doped with thermally conductive particles. A laser radar is improved, comprising: a laser light source for emitting laser light; and a light modulator provided on an emission path of the laser light emitted by the laser light source, the light modulator being as requested The light modulator according to any one of items 1-7.