Light-emitting component, light-emitting device, and image forming apparatus
A light-emitting component includes a substrate, a light-emitting element, a thyristor, and a light-transmission reduction layer. The light-emitting element is disposed on the substrate. The thyristor causes the light-emitting element to emit light or causes an amount of light emitted by the light-emitting element to increase, upon entering an on-state. The light-transmission reduction layer is disposed between the light-emitting element and the thyristor such that the light-emitting element and the thyristor are stacked, and suppresses light emitted by the thyristor from passing therethrough.
1. A light-emitting component comprising:
a substrate;
a light-emitting element disposed on the substrate;
a thyristor that causes the light-emitting element to emit light or causes an amount of light emitted by the light-emitting element to increase, upon entering an on-state; and
a light-transmission reduction layer that is disposed between the light-emitting element and the thyristor such that the light-emitting element and the thyristor are stacked, the light-transmission reduction layer being at least one semiconductor layer and being configured to suppress light from the thyristor to the light-emitting element, wherein the light-transmission reduction layer is disposed on the light-emitting element and the thyristor is disposed on the light-transmission reduction layer.
2. The light-emitting component according to claim 1 , wherein the light emitted by the light-emitting element and the light emitted by the thyristor have different wavelengths.
3. The light-emitting component according to claim 1 , wherein the light-transmission reduction layer includes a semiconductor layer having a bandgap energy smaller than a bandgap energy equivalent to the light emitted by the thyristor.
4. The light-emitting component according to claim 2 , wherein the light-transmission reduction layer includes a semiconductor layer having a bandgap energy smaller than a bandgap energy equivalent to the light emitted by the thyristor.
5. The light-emitting component according to claim 2 , wherein
each of the light-emitting element and the thyristor includes a plurality of semiconductor layers that are stacked, and
the light-transmission reduction layer includes a semiconductor layer having a conductivity type identical to a conductivity type of one of a light-emitting-element-side semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the light-emitting element and a thyristor-side semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the thyristor, and having an impurity concentration higher than an impurity concentration of the one of the light-emitting-element-side semiconductor layer and the thyristor-side semiconductor layer.
6. The light-emitting component according to claim 2 , wherein
each of the light-emitting element and the thyristor includes a plurality of semiconductor layers that are stacked, and
the light-transmission reduction layer is configured to maintain a direction in which a current easily flows in a case where a light-emitting-element-side semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the light-emitting element and a thyristor-side semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the thyristor are directly joined.
7. The light-emitting component claim 2 , wherein
each of the light-emitting element, the thyristor, and the light-transmission reduction layer includes a plurality of semiconductor layers that are stacked,
a semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the thyristor and a semiconductor layer that is in contact with the thyristor among the plurality of semiconductor layers of the light-transmission reduction layer have an identical conductivity type,
a semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the light-emitting element and a semiconductor layer that in is in contact with the light-emitting element among the plurality of semiconductor layers of the light-transmission reduction layer have an identical conductivity type,
the semiconductor layer that is in contact with the thyristor among the plurality of semiconductor layers of the light-transmission reduction layer has an impurity concentration higher than an impurity concentration of the semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the thyristor, and
the semiconductor layer that in is in contact with the light-emitting element among the plurality of semiconductor layers of the light-transmission reduction layer has an impurity concentration higher than an impurity concentration of the semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the light-emitting element.
8. The light-emitting component claim 1 , wherein the thyristor further includes a voltage reduction layer that reduces a rising voltage of the thyristor.
9. The light-emitting component according to claim 8 , wherein the voltage reduction layer has a bandgap energy that is smaller than bandgap energies of other semiconductor layers of the thyristor.
10. A light-emitting device comprising:
a plurality of light-emitting components that are caused to sequentially emit light, each of the plurality of light-emitting components being the light-emitting component claim 1 ; and
an optical system that emits light emitted from the light-emitting components two-dimensionally.
11. An image forming apparatus comprising:
an image bearing member;
a charging member that charges the image bearing member;
the light-emitting device according to claim 10 that exposes the image bearing member that has been charged to light;
a developing member that develops an electrostatic latent image formed on the image bearing member that has been exposed to light by the light-emitting device; and
a transfer member that transfers an image developed on the image bearing member onto a transferred-image-receiving medium.
12. The light-emitting component according to claim 1 , wherein the light-transmission reduction layer includes a plurality of semiconductor layers.
13. The light-emitting component according to claim 1 , wherein the light-emitting element is a laser element.
14. The light-emitting component according to claim 1 , wherein the lighting element is a VCSEL element.
15. A light-emitting component comprising:
a substrate;
a light-emitting element disposed on the substrate;
a thyristor that causes the light-emitting element to emit light or causes an amount of light emitted by the light-emitting element to increase, upon entering an on-state; and
a light-transmission reduction layer that is disposed between the light-emitting element and the thyristor such that the light-emitting element and the thyristor are stacked and that suppresses light emitted by the thyristor from passing therethrough, wherein
each of the light-emitting element and the thyristor includes a plurality of semiconductor layers that are stacked, and
the light-transmission reduction layer includes a semiconductor layer having a conductivity type identical to a conductivity type of one of a light-emitting-element-side semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the light-emitting element and a thyristor-side semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the thyristor, and having an impurity concentration higher than an impurity concentration of the one of the light-emitting-element-side semiconductor layer and the thyristor-side semiconductor layer.
16. A light-emitting component comprising:
a substrate;
a light-emitting element disposed on the substrate;
a thyristor that causes the light-emitting element to emit light or causes an amount of light emitted by the light-emitting element to increase, upon entering an on-state; and
a light-transmission reduction layer that is disposed between the light-emitting element and the thyristor such that the light-emitting element and the thyristor are stacked and that suppresses light emitted by the thyristor from passing therethrough, wherein
each of the light-emitting element and the thyristor includes a plurality of semiconductor layers that are stacked, and
the light-transmission reduction layer is configured to maintain a direction in which a current easily flows in a case where a light-emitting-element-side semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the light-emitting element and a thyristor-side semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the thyristor are directly joined.
17. A light-emitting component comprising:
a substrate;
a light-emitting element disposed on the substrate;
a thyristor that causes the light-emitting element to emit light or causes an amount of light emitted by the light-emitting element to increase, upon entering an on-state; and
a light-transmission reduction layer that is disposed between the light-emitting element and the thyristor such that the light-emitting element and the thyristor are stacked and that suppresses light emitted by the thyristor from passing therethrough, wherein
each of the light-emitting element, the thyristor, and the light-transmission reduction layer includes a plurality of semiconductor layers that are stacked,
a semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the thyristor and a semiconductor layer that is in contact with the thyristor among the plurality of semiconductor layers of the light-transmission reduction layer have an identical conductivity type,
a semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the light-emitting element and a semiconductor layer that in is in contact with the light-emitting element among the plurality of semiconductor layers of the light-transmission reduction layer have an identical conductivity type,
the semiconductor layer that is in contact with the thyristor among the plurality of semiconductor layers of the light-transmission reduction layer has an impurity concentration higher than an impurity concentration of the semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the thyristor, and
the semiconductor layer that in is in contact with the light-emitting element among the plurality of semiconductor layers of the light-transmission reduction layer has an impurity concentration higher than an impurity concentration of the semiconductor layer that is in contact with the light-transmission reduction layer among the plurality of semiconductor layers of the light-emitting element.
18. A light-emitting component comprising:
a substrate;
a plurality of light-emitting elements disposed on the substrate;
a plurality of thyristors that are stacked on the plurality of light-emitting elements with a light-transmission reduction layer interposed therebetween, each of the plurality of thyristors being configured to cause a corresponding one of the plurality of light-emitting elements to emit light or cause an amount of light emitted by the corresponding one of the plurality of light-emitting elements to increase, upon entering an on-state;
a plurality of transfer elements that are stacked on respective lower elements with a light-transmission reduction layer interposed therebetween, each of the plurality of transfer elements being configured to set, upon entering the on-state, a corresponding one of the thyristors to be ready to enter the on-state, the lower elements having a layered structure identical to a layered structure of the plurality of light-emitting elements; and
a connection wire that causes the lower elements not to operate as the light-emitting elements.
19. The light-emitting component claim 18 , wherein the light-transmission reduction layer is a semiconductor layer disposed on the plurality of light-emitting elements and the plurality of light-emitting elements are laser elements.
20. A light-emitting component comprising:
a light-emitting element that is disposed on a substrate;
a driving element that is disposed on the light-emitting element and that drives the light-emitting element; and
a light-transmission reduction layer that is disposed between the light-emitting element and the driving element, the light-transmission reduction layer being a semiconductor layer and being configured to suppress light from the driving element to the light-emitting element, wherein the light-transmission reduction layer is disposed on the light-emitting element and the driving element is disposed on the light-transmission reduction layer.