CN105679916A - Light-emitting device with adjustable color temperature - Google Patents

Abstract

The invention belongs to the field of optics, and more specifically relates to a light-emitting device with adjustable color temperature, which is characterized in that it includes a set of long-wavelength chips (101), a set of short-wavelength chips (102), a photoluminescent layer (104) and a color mixing The light emitted by the long-wavelength chip (101) and the short-wavelength chip (102) is mixed by the color-mixing structure and then emitted, and the photoluminescence layer (104) is located in the outgoing light path of the color-mixing structure. The light-emitting device with adjustable color temperature provided by the present invention can use multi-wavelength blue light to excite and adjust the spectrum of photoluminescence, thereby realizing the adjustment of the ratio of cool and warm white light, completing the change of color temperature, and having a wide adjustable range.

Description

A light emitting device with adjustable color temperature

technical field

The invention belongs to the field of optics, and more specifically relates to a light emitting device with adjustable color temperature.

Background technique

The backlight/light-emitting technology with adjustable color temperature has been a hot spot in the field of lighting and display research and development in recent years. Because people's visual perception when using display devices to watch is directly related to the color temperature of backlight lighting, for example, people are viewing photos, videos, playing games, etc. For occasions, we tend to use cool white light with high color temperature to enhance contrast and image details; while when reading text, we hope to use warm white light with low color temperature for lighting to make eyes feel comfortable and reduce visual fatigue. Therefore, the study of adjustable color temperature technology has important practical value.

For this reason, scientists from all over the world have conducted extensive research. For example, Taiwan Platinum Technology has proposed a technology based on LED mixing of multiple wavelengths to achieve light color change. Although this technology can realize the adjustment of the color coordinates and color temperature of the illumination light, However, there are problems of complex control and uniformity of light mixing, and its large size makes it difficult to integrate with the backlight manufacturing process in flat panel displays. Philips provides a color-tunable lighting assembly whose lighting layer absorbs and converts light of a first color into light of a second color. By actively controlling the temperature of the lighting layer with a temperature control device, the light emission of the lighting assembly can be adjusted, thereby changing the color. This design can effectively change the color of the lighting, but it requires an external temperature control device to regulate, in addition to complicated control, slow response, and difficult to achieve miniaturization. Therefore, it is of great significance to study the color temperature adjustable backlight lighting technology with good uniformity, fast response speed and simple control method to improve the performance of flat-panel display devices or modules and enhance visual comfort.

Contents of the invention

In order to overcome at least one defect (deficiency) of the above-mentioned prior art, the present invention provides a light emitting device with adjustable color temperature.

In order to solve the problems of the technologies described above, the technical solution of the present invention is as follows:

A light-emitting device with adjustable color temperature, characterized in that it includes a set of long-wavelength chips, a set of short-wavelength chips, a photoluminescent layer and a color-mixing structure, and the light emitted by the long-wavelength chips and short-wavelength chips is mixed by the color-mixing structure The photoluminescent layer is located in the outgoing light path of the color mixing structure.

Further, as a preferred technical solution, the long-wavelength chip is a long-wavelength blue LED or OLED chip, and the short-wavelength chip is a short-wavelength blue LED or OLED chip.

Further, as a preferred technical solution, the color mixing structure is a reflective cup, and the photoluminescent layer is coated on the reflective cup.

Further, as a preferred technical solution, the color mixing structure is a reflective cup, and the photoluminescent layer is encapsulated in the reflective cup.

Further, as a preferred technical solution, a scattering sheet is also included, and the scattering sheet is located in the outgoing light path of the color mixing structure and behind the photoluminescent layer.

Further, as a preferred technical solution, the color mixing structure is a transmissive light guide structure, the transmissive light guide structure includes a light guide structure and a reflective layer, the reflective layer is located at the bottom of the light guide structure, and the photoluminescent layer is located at the bottom of the light guide structure. top of the structure.

Further, as a preferred technical solution, the set of long-wavelength chips and the set of short-wavelength chips are respectively side-entry long-wavelength blue LED or OLED chip arrays and side-entry short-wavelength blue LED or OLED chip arrays.

Further, as a preferred technical solution, a scattering sheet is also included, and the scattering sheet is located in the outgoing light path of the color mixing structure and behind the photoluminescent layer.

Further, as a preferred technical solution, a brightness enhancement film and a bidirectional brightness enhancement film are also included, and the brightness enhancement film and the bidirectional brightness enhancement film are located in the outgoing light path of the color mixing structure and behind the photoluminescent layer.

Further, as a preferred technical solution, the main component of the photoluminescent layer is phosphor, quantum dot material or nanocrystal material.

Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

The color temperature adjustable light-emitting device provided by the present invention can be excited by multi-wavelength blue light to generate photoluminescence with adjustable color temperature. The characteristics of the obvious difference in excitation efficiency allow blue light of different wavelengths to mix uniformly in the light guide plate or mixing cavity, and then allow the film layer coated with photoluminescent material to be luminescent and excited by the blue light at the same time. Due to the difference in luminous efficiency of photoluminescent materials for blue light of different wavelengths, it can produce white light of cool and warm colors with different color temperatures. When the light intensity ratio of these blue lights is changed, the color light intensity emitted by the photoluminescent material, and the relative intensity ratio of these color lights and blue light also change accordingly, thereby realizing the adjustment of the ratio of cold and warm white light, that is, completing the adjustment of the color temperature. The utility model has the advantages of wide adjustable range, simple control and fast response, which is conducive to realizing miniaturization.

Description of drawings

Fig. 1 is a schematic structural diagram of Embodiment 1 of the present invention.

Fig. 2 is a schematic structural diagram of Embodiment 2 of the present invention.

Fig. 3 is a schematic structural diagram of Embodiment 3 of the present invention.

Fig. 4 is a schematic structural diagram of Embodiment 4 of the present invention.

Fig. 5 is a schematic structural diagram of Embodiment 5 of the present invention.

Fig. 6 shows the present invention Fig. 7 is a spectrum diagram taking red and green quantum dots as an example.

The accompanying drawings are for illustrative purposes only, and should not be construed as limitations on this patent; in order to better illustrate this embodiment, certain components in the accompanying drawings will be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art For personnel, it is understandable that some known structures and descriptions thereof may be omitted in the drawings; the same or similar symbols correspond to the same or similar components; as a limitation of this patent.

detailed description

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example 1

A light-emitting device with adjustable color temperature, as shown in FIG. The light emitted by the short-wavelength blue LED chip 102 is mixed with the color-mixing structure and then emitted; the photoluminescent layer 104 is located in the outgoing light path of the color-mixing structure; the color-mixing structure is a reflective cup 103, and the photoluminescent layer 104 encapsulates In the reflection cup 103 ; the main component of the photoluminescent layer is photoluminescent material, including but not limited to fluorescent powder, quantum dot material, nano crystal material and the like.

When in use, the blue light emitted by the blue LED chips 101 and 102 is reflected by the reflective cup 103 and then mixed and emitted to the photoluminescent layer 104. Because the photoluminescent material is excited by the blue light, it will emit color light with a certain intensity and spectral distribution. The blue light of the long and short wavelengths mixes to form the outgoing white light. Photoluminescent materials have different absorption and excitation efficiencies for different wavelengths of blue light. Taking photoluminescent materials as red and green quantum dots (nanocrystals) as an example, shorter wavelength blue light is absorbed and excited more efficiently, so the excitation The red and green light intensity of the long-wavelength blue light is also higher, and the white light obtained after mixing has a lower color temperature and a warmer color; on the contrary, the red and green light intensity excited by long-wavelength blue light is lower, the color temperature is higher, and the color is cooler. Therefore, by adjusting the relative intensity of the two kinds of blue light, the intensity of red and green light excited by the photoluminescent material can be changed, the synthesis ratio of cold and warm white light can be adjusted, and finally the adjustable function of the color temperature of white light can be realized. The luminous intensity of the two blue lights can be adjusted individually by the light source control circuit.

Example 2

This embodiment is similar to Embodiment 2, further, the light emitting device with adjustable color temperature further includes a scattering sheet 105 , and the scattering sheet 105 is located in the outgoing light path of the color mixing structure and behind the photoluminescent layer 104 .

When in use, the photoluminescent material is excited by the blue light and emits a certain intensity and wave color light, which is mixed with the blue light to form white light, which is emitted after being softened by the scattering sheet 105 .

Example 3

A light-emitting device with adjustable color temperature, as shown in FIG. 3 , includes a group of long-wavelength blue LED chips 101, a group of short-wavelength blue LED chips 102, a photoluminescent layer 104 and a color mixing structure. The long-wavelength blue LED chips 101 The light emitted by the short-wavelength blue LED chip 102 is mixed with the color mixing structure and then emitted. The photoluminescent layer 104 is located in the outgoing light path of the color mixing structure; the color mixing structure is a reflective cup 103, and the photoluminescent layer 104 is coated with cloth on the reflection cup 103.

The usage method of this embodiment is similar to embodiment 1.

Example 4

A light-emitting device with adjustable color temperature, as shown in FIG. 4 , includes a set of side-entry long-wavelength blue LED chip arrays 201, a set of side-entry short-wavelength blue LED chip arrays 202, a photoluminescent layer 104 and a color mixing structure, The color mixing structure is a transmissive light guide structure, the transmissive light guide structure includes a light guide structure 203 and a light reflective layer 204, the light reflective layer 204 is located at the bottom of the light guide structure 203 (such as a light guide plate), and the photoluminescent layer 104 is located On the top of the light guide structure 203, the side-entry long-wavelength blue LED chip array 201 and the short-wavelength blue LED chip array 202 are located on the side of the light guide structure 203, and the two arrays may be located on the same side or not on the same side; The light emitted by the long-wavelength blue LED chip 201) and the short-wavelength blue LED long chip 202 are mixed by the color mixing structure and then emitted, and the photoluminescent layer 104 is located in the outgoing light path of the color mixing structure; it also includes a scattering sheet 105, the The scattering sheet 105 is located in the outgoing light path of the color mixing structure and behind the photoluminescent layer 104 .

In the method of use, the white light emitted by the side-entry LED is reflected by the transmissive light guide structure and then emerges from the upper surface to the photoluminescent layer 104. The main component of the photoluminescent layer 104 is photoluminescent materials, including but not limited to phosphors, quantum dots materials, nanocrystalline materials, etc. Because the photoluminescent material is excited by the blue light, it will emit a certain intensity and wave color light, which is mixed with the blue light to form white light. The photoluminescent material has different absorption and excitation efficiencies for different wavelengths of blue light. Taking red and green quantum dots (nanocrystals) as an example, shorter-wavelength blue light is more efficiently absorbed and excited, so the intensity of the excited red and green light is also higher, and the white light obtained after mixing has a lower color temperature and a warmer color ; On the contrary, the intensity of red and green light excited by long-wavelength blue light is lower, the color temperature is higher, and the color is cooler. Therefore, by adjusting the relative intensity of the two kinds of blue light, the intensity of red and green light excited by the photoluminescent material can be changed, the synthesis ratio of cold and warm white light can be adjusted, and finally the adjustable function of the color temperature of white light can be realized. The luminous intensity of the two blue lights can be adjusted individually by the light source control circuit.

Example 5

This embodiment is similar to Embodiment 4. Further, the color temperature adjustable light emitting device further includes a brightness enhancement film 303 and a bidirectional brightness enhancement film 304, and the brightness enhancement film 303 and the bidirectional brightness enhancement film 304 are located at the exit light of the color mixing structure. In the middle of the road and behind the photoluminescent layer 104 .

The usage method of this embodiment is similar to that of Embodiment 4. Furthermore, during use, the emitted white light becomes the LCD backlight surface light source after passing through the Brightness Enhancement Film (BEF) 303 and the Bidirectional Brightness Enhancement Film (DBEF) 304 .

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (10)

1. A light-emitting device with adjustable color temperature, characterized in that it includes a set of long-wavelength chips (101), a set of short-wavelength chips (102), a photoluminescent layer (104) and a color mixing structure, and the long-wavelength chips ( 101) and the light emitted by the short-wavelength chip (102) are mixed by the color-mixing structure and then emitted, and the photoluminescence layer (104) is located in the outgoing light path of the color-mixing structure. 2. The light-emitting device with adjustable color temperature according to claim 1, characterized in that, the long-wavelength chip (101) is a long-wavelength blue LED or OLED chip, and the short-wavelength chip (102) is a short-wavelength blue LED or OLED chips. 3. The light-emitting device with adjustable color temperature according to any one of claims 1-2, characterized in that, the color mixing structure is a reflective cup (103), and the photoluminescent layer (104) is coated on the reflective cup ( 103) on. 4. The light emitting device with adjustable color temperature according to any one of claims 1-2, characterized in that, the color mixing structure is a reflective cup (103), and the photoluminescent layer (104) is encapsulated in the reflective cup (103) )Inside. 5. The light-emitting device with adjustable color temperature according to claim 4, characterized in that it further comprises a scattering sheet (105), the scattering sheet (105) is located in the outgoing light path of the color mixing structure, and is located in the photoluminescent layer ( 104) after. 6. The light-emitting device with adjustable color temperature according to any one of claims 1-2, characterized in that, the color mixing structure is a transmission light guide structure, and the transmission light guide structure includes a light guide structure (203) and a light reflection layer (204 ), the reflective layer (204) is located at the bottom of the light guiding structure (203), and the photoluminescence layer (104) is located at the top of the light guiding structure (203). 7. The light-emitting device with adjustable color temperature according to claim 6, characterized in that, the set of long-wavelength chips and the set of short-wavelength chips are respectively side-entry long-wavelength blue LED or OLED chip arrays (201) and side An embedded short-wavelength blue LED or OLED chip array (202). 8. The light-emitting device with adjustable color temperature according to claim 7, characterized in that it further comprises a scattering sheet (105), the scattering sheet (105) is located in the outgoing light path of the color mixing structure, and is located in the photoluminescent layer ( 104) after. 9. The light emitting device with adjustable color temperature according to claim 7, characterized in that it further comprises a brightness enhancement film (303) and a two-way brightness enhancement film (304), the brightness enhancement film (303) and the two-way brightness enhancement film ( 304) is located in the exit light path of the color mixing structure and behind the photoluminescent layer (104). 10. The light-emitting device with adjustable color temperature according to any one of claims 1-9, characterized in that the main components of the photoluminescent layer include fluorescent powder, quantum dot material or nano-crystal material.